Tritium-caused background currents in electron multipliers

International Nuclear Information System (INIS)

Malinowski, M.E.

1979-05-01

One channel electron multiplier (Galileo No. 4501) and one 14 stage Be/Cu multiplier (Dumont No. SPM3) were exposed to tritium pressures between approx. 10 -7 Torr to 10 -3 Torr in amounts from approx. 10 -5 Torr-s to 60 Torr-s and the β-decay caused currents in the multipliers measured. The background currents in both multipliers consisted of two components: (1) a high, reversible current which was proportional to the tritium exposure pressure; and (2) a lower, irreversible background current which increased with increasing cumulative tritium exposure. The β-decay caused currents in each multiplier increased the same way with exposure, suggesting the detected electrons arose from decaying tritium adsorbed on surfaced external to the multipliers

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)

Calculated characteristics of multichannel photoelectron multipliers

International Nuclear Information System (INIS)

Vasil'chenko, V.G.; Dajkovskij, A.G.; Milova, N.V.; Rakhmatov, V.E.; Rykalin, V.I.

1990-01-01

Structural features and main calculated characteristics of some modifications of position-sensitive two-coordinate multichannel photoelectron multipliers (PEM) with plate-type multiplying systems are described. The presented PEM structures are free from direct optical and ion feedbacks, provide coordinate resolution ≅ 1 mm with efficiency of photoelectron detection ≅ 90%. Capabilities for using silicon field-effect photocathodes, providing electron extraction into vacuum, as well as prospects of using multichannel multiplying systems for readout of the data from solid detectors are considered

Design of two easily-testable VLSI array multipliers

Energy Technology Data Exchange (ETDEWEB)

Ferguson, J.; Shen, J.P.

1983-01-01

Array multipliers are well-suited to VLSI implementation because of the regularity in their iterative structure. However, most VLSI circuits are very difficult to test. This paper shows that, with appropriate cell design, array multipliers can be designed to be very easily testable. An array multiplier is called c-testable if all its adder cells can be exhaustively tested while requiring only a constant number of test patterns. The testability of two well-known array multiplier structures are studied. The conventional design of the carry-save array multipler is shown to be not c-testable. However, a modified design, using a modified adder cell, is generated and shown to be c-testable and requires only 16 test patterns. Similar results are obtained for the baugh-wooley two's complement array multiplier. A modified design of the baugh-wooley array multiplier is shown to be c-testable and requires 55 test patterns. The implementation of a practical c-testable 16*16 array multiplier is also presented. 10 references.

A high-order perturbation of surfaces method for scattering of linear waves by periodic multiply layered gratings in two and three dimensions

Science.gov (United States)

Hong, Youngjoon; Nicholls, David P.

2017-09-01

The capability to rapidly and robustly simulate the scattering of linear waves by periodic, multiply layered media in two and three dimensions is crucial in many engineering applications. In this regard, we present a High-Order Perturbation of Surfaces method for linear wave scattering in a multiply layered periodic medium to find an accurate numerical solution of the governing Helmholtz equations. For this we truncate the bi-infinite computational domain to a finite one with artificial boundaries, above and below the structure, and enforce transparent boundary conditions there via Dirichlet-Neumann Operators. This is followed by a Transformed Field Expansion resulting in a Fourier collocation, Legendre-Galerkin, Taylor series method for solving the problem in a transformed set of coordinates. Assorted numerical simulations display the spectral convergence of the proposed algorithm.

Faster Double-Size Bipartite Multiplication out of Montgomery Multipliers

Science.gov (United States)

Yoshino, Masayuki; Okeya, Katsuyuki; Vuillaume, Camille

This paper proposes novel algorithms for computing double-size modular multiplications with few modulus-dependent precomputations. Low-end devices such as smartcards are usually equipped with hardware Montgomery multipliers. However, due to progresses of mathematical attacks, security institutions such as NIST have steadily demanded longer bit-lengths for public-key cryptography, making the multipliers quickly obsolete. In an attempt to extend the lifespan of such multipliers, double-size techniques compute modular multiplications with twice the bit-length of the multipliers. Techniques are known for extending the bit-length of classical Euclidean multipliers, of Montgomery multipliers and the combination thereof, namely bipartite multipliers. However, unlike classical and bipartite multiplications, Montgomery multiplications involve modulus-dependent precomputations, which amount to a large part of an RSA encryption or signature verification. The proposed double-size technique simulates double-size multiplications based on single-size Montgomery multipliers, and yet precomputations are essentially free: in an 2048-bit RSA encryption or signature verification with public exponent e=216+1, the proposal with a 1024-bit Montgomery multiplier is at least 1.5 times faster than previous double-size Montgomery multiplications.

Effective switching frequency multiplier inverter

Science.gov (United States)

Su, Gui-Jia [Oak Ridge, TN; Peng, Fang Z [Okemos, MI

2007-08-07

A switching frequency multiplier inverter for low inductance machines that uses parallel connection of switches and each switch is independently controlled according to a pulse width modulation scheme. The effective switching frequency is multiplied by the number of switches connected in parallel while each individual switch operates within its limit of switching frequency. This technique can also be used for other power converters such as DC/DC, AC/DC converters.

Multipliers for continuous frames in Hilbert spaces

International Nuclear Information System (INIS)

Balazs, P; Bayer, D; Rahimi, A

2012-01-01

In this paper, we examine the general theory of continuous frame multipliers in Hilbert space. These operators are a generalization of the widely used notion of (discrete) frame multipliers. Well-known examples include anti-Wick operators, STFT multipliers or Calderón–Toeplitz operators. Due to the possible peculiarities of the underlying measure spaces, continuous frames do not behave quite as their discrete counterparts. Nonetheless, many results similar to the discrete case are proven for continuous frame multipliers as well, for instance compactness and Schatten-class properties. Furthermore, the concepts of controlled and weighted frames are transferred to the continuous setting. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical devoted to ‘Coherent states: mathematical and physical aspects’. (paper)

Lagrange multipliers and gravitational theory

International Nuclear Information System (INIS)

Elston, F.D.

1977-01-01

The Lagrange multiplier variational method is extended to nonlinear Lagrangians in a Riemann space, where it is shown explicitly for the quadratic Lagrangians that, as expected, this approach is equivalent to the Hilbert variational method. It is not, in general, equivalent to the Palatini variational method. The nonvanishing Lagrange multipliers for the quadratic Lagrangians are explicitly obtained in covariant form. A similiar analysis is then carried out in a Riemann--Cartan torsional metric space for the specific Lagrangians g/sup 1/2/R tilde and g/sup 1/2/R/sub uv/tilde R/sup uv/tilde. The possible relevance of the R/sub uv/R/sup u anti v/ invariant to an action-principle formulation of the Rainich--Misner--Wheeler (RMW) already-unified theory is also discussed. It is then pointed out how a different use of the Lagrange multiplier technique in the language of the 3 + 1 canonical formalism developed by Arnowitt, Deser, and Misner (ADM) permits the recasting of the equations of motion for quadratic and general higher-order invariants into the ADM canonical formalism. In general, without this Lagrange multiplier approach, the higher-order ADM problem could not be solved. This is done explicitly for the simplest quadratic Langrangian g/sup 1/2/R 2 as an example

Keynesian multiplier versus velocity of money

Science.gov (United States)

Wang, Yougui; Xu, Yan; Liu, Li

2010-08-01

In this paper we present the relation between Keynesian multiplier and the velocity of money circulation in a money exchange model. For this purpose we modify the original exchange model by constructing the interrelation between income and expenditure. The random exchange yields an agent's income, which along with the amount of money he processed determines his expenditure. In this interactive process, both the circulation of money and Keynesian multiplier effect can be formulated. The equilibrium values of Keynesian multiplier are demonstrated to be closely related to the velocity of money. Thus the impacts of macroeconomic policies on aggregate income can be understood by concentrating solely on the variations of money circulation.

Study of heterogeneous multiplying and non-multiplying media by the neutron pulsed source technique

International Nuclear Information System (INIS)

Deniz, V.

1969-01-01

The pulsed neutron technique consists essentially in sending in the medium to be studied a short neutron pulse and in determining the asymptotic decay constant of the generated population. The variation of the decay constant as a function of the size of the medium allows the medium characteristics to be defined. This technique has been largely developed these last years and has been applied as well to moderator as to multiplying media, in most cases homogeneous ones. We considered of interest of apply this technique to lattices, to see if useful informations could be collected for lattice calculations. We present here a general theoretical study of the problem, and results and interpretation of a series of experiments made on graphite lattices. There is a good agreement for non-multiplying media. In the case of multiplying media, it is shown that the age value used until now in graphite lattices calculations is over-estimated by about 10 per cent [fr

On compact multipliers of topological algebras

International Nuclear Information System (INIS)

Mohammad, N.

1994-08-01

It is shown that if the maximal ideal space Δ(A) of a semisimple commutative complete metrizable locally convex algebra contains no isolated points, then every compact multiplier is trivial. Particularly, compact multipliers on semisimple commutative Frechet algebras whose maximal ideal space has no isolated points are identically zero. (author). 5 refs

Convergence analysis of the rebalance methods in multiplying finite slab having periodic boundary conditions

International Nuclear Information System (INIS)

Hong, Ser Gi; Lee, Young Ouk; Song, Jae Seung

2009-01-01

This paper analyzes the convergence of the rebalance iteration methods for the discrete ordinates transport equation in the multiplying finite slab problem. The finite slab is assumed to be homogeneous and it has the periodic boundary conditions. A general formulation is used to include three well-known rebalance methods of the linearized form in a unified way. The rebalance iteration methods considered in this paper are the CMR (Coarse-Mesh Rebalance), the CMFD (Coarse-Mesh Finite Difference), and p-CMFD (Partial Current-Based Coarse Mesh Finite Difference) methods which have been popularly used in the reactor physics. The convergence analysis is performed with the well-known Fourier analysis through a linearization. The analyses are applied for one-group problems. The theoretical analysis shows that there are one fundamental mode and N-1 Eigen-modes which determine the convergence if the finite slab is divided into N uniform meshes. The numerical tests show that the Fourier convergence analysis provides the reasonable estimate of the numerical spectral radii for the model problems and the spectral radius for the finite slab approaches the one for the infinite slab as the thickness of the slab increases. (author)

Optical studies of multiply excited states

International Nuclear Information System (INIS)

Mannervik, S.

1989-01-01

Optical studies of multiply-excited states are reviewed with emphasis on emission spectroscopy. From optical measurements, properties such as excitation energies, lifetimes and autoionization widths can be determined with high accuracy, which constitutes a challenge for modern computational methods. This article mainly covers work on two-, three- and four-electron systems, but also sodium-like quartet systems. Furthermore, some comments are given on bound multiply-excited states in negative ions. Fine structure effects on transition wavelengths and lifetimes (autoionization) are discussed. In particular, the most recent experimental and theoretical studies of multiply-excited states are covered. Some remaining problems, which require further attention, are discussed in more detail. (orig.) With 228 refs

Fourier-muunnoksesta

OpenAIRE

NIEMELÄ, EERO

2008-01-01

Tutkielman aiheena on Fourier-muunnoksen esittely. Tarkoituksena on erityisesti johdatella lukija Fourier-sarjan ja -muunnoksen käsitteisiin. Fourier-muunnosten teoria kuuluu yleisempään Fourier-analyysin aihepiiriin. Fourier-analyysin keskiössä on tulos, jonka mukaan tietyt ehdot täyttävää funktiota voidaan approksimoida mielivaltaisen tarkasti niin sanotun Fourier-sarjan avulla. Osoitamme, että 2\\pi-jaksollisen funktion Lebesgue-neliöintegroituvuus takaa suppenevan Fourier-sarjakehitelm...

Otanps synapse linear relation multiplier circuit

International Nuclear Information System (INIS)

Chible, H.

2008-01-01

In this paper, a four quadrant VLSI analog multiplier will be proposed, in order to be used in the implementation of the neurons and synapses modules of the artificial neural networks. The main characteristics of this multiplier are the small silicon area and the low power consumption and the high value of the weight input voltage. (author)

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

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…

Reference: 282 [Arabidopsis Phenome Database[Archive

Lifescience Database Archive (English)

Full Text Available 282 http://metadb.riken.jp/db/SciNetS_ria224i/cria224u4ria224u16214903i Kasahara Ryushiro...abidopsis. 11 2981-92 16214903 2005 Nov The Plant cell Drews Gary N|Kasahara Ryushiro D|Portereiko Michael F|Rabiger David S|Sandaklie-Nikolova Linda

The Multiplier Effect.

Science.gov (United States)

Flowers, William L., Jr.; Harris, John B.

1981-01-01

The multiplier effect is discussed as it applies to the field of continuing education. The authors' main point is that one grant or contract can, and should, be used as the basis for building organizational competencies and capabilities that will secure other funds. (Author/CT)

Hadamard Multipliers and Abel Dual of Hardy Spaces

Directory of Open Access Journals (Sweden)

Paweł Mleczko

2016-01-01

Full Text Available The paper is devoted to the study of Hadamard multipliers of functions from the abstract Hardy classes generated by rearrangement invariant spaces. In particular the relation between the existence of such multiplier and the boundedness of the appropriate convolution operator on spaces of measurable functions is presented. As an application, the description of Hadamard multipliers into H∞ is given and the Abel type theorem for mentioned Hardy spaces is proved.

Efek Multiplier Zakat terhadap Pendapatan di Provinsi DKI Jakarta

OpenAIRE

Al Arif, M. Nur Rianto

2012-01-01

The aim of this research is to analyse the multiplier effect of zakâh revenue in DKI Jakarta. A study case at Badan Amil Zakat, Infak, and Sadaqah (BAZIS) DKI Jakarta. Least square method is used to analyze the data. The coefficients will be used to calculate the multiplier effect of zakâh-revenue and it will be compared with the economy without zakah revenue. The results showed 2,522 multiplier effects of zakâh-revenue and 3.561 multiplier effect ofeconomic income without zakâh-revenue. Thi...

φ-Multipliers on Banach Algebras and Topological Modules

OpenAIRE

Adib, Marjan

2015-01-01

We prove some results concerning Arens regularity and amenability of the Banach algebra ${M}_{\\phi }(A)$ of all $\\phi $ -multipliers on a given Banach algebra $A$ . We also consider $\\phi $ -multipliers in the general topological module setting and investigate some of their properties. We discuss the $\\phi $ -strict and $\\phi $ -uniform topologies on ${M}_{\\phi }(A)$ . A characterization of $\\phi $ -multipliers on ${L}_{1}(G)$ -module ${L}_{p}(G)$ , where $G$ is a compact group, is given.

Single electron based binary multipliers with overflow detection ...

African Journals Online (AJOL)

electron based device. Multipliers with overflow detection based on serial and parallel prefix computation algorithm are elaborately discussed analytically and designed. The overflow detection circuits works in parallel with a simplified multiplier to ...

Isometric multipliers of a vector valued Beurling algebra on a ...

Indian Academy of Sciences (India)

Home; Journals; Proceedings – Mathematical Sciences; Volume 127; Issue 1. Isometric multipliers of a vector valued Beurling algebra on a discrete semigroup. Research Article Volume 127 Issue 1 February 2017 pp 109- ... Keywords. Weighted semigroup; multipliers of a semigroup; Beurling algebra; isometric multipliers.

Economic Multipliers and Mega-Event Analysis

OpenAIRE

Victor Matheson

2004-01-01

Critics of economic impact studies that purport to show that mega-events such as the Olympics bring large benefits to the communities “lucky” enough to host them frequently cite the use of inappropriate multipliers as a primary reason why these impact studies overstate the true economic gains to the hosts of these events. This brief paper shows in a numerical example how mega-events may lead to inflated multipliers and exaggerated claims of economic benefits.

Spin sensitivity of a channel electron multiplier

International Nuclear Information System (INIS)

Scholten, R.E.; McClelland, J.J.; Kelley, M.H.; Celotta, R.J.

1988-01-01

We report direct measurements of the sensitivity of a channel electron multiplier to electrons with different spin orientations. Four regions of the multiplier cone were examined using polarized electrons at 100-eV incident energy. Pulse counting and analog modes of operation were both investigated and in each case the observed spin effects were less than 0.5%

Sociophysics of sexism: normal and anomalous petrie multipliers

Science.gov (United States)

Eliazar, Iddo

2015-07-01

A recent mathematical model by Karen Petrie explains how sexism towards women can arise in organizations where male and female are equally sexist. Indeed, the Petrie model predicts that such sexism will emerge whenever there is a male majority, and quantifies this majority bias by the ‘Petrie multiplier’: the square of the male/female ratio. In this paper—emulating the shift from ‘normal’ to ‘anomalous’ diffusion—we generalize the Petrie model to a stochastic Poisson model that accommodates heterogeneously sexist men and woman, and that extends the ‘normal’ quadratic Petrie multiplier to ‘anomalous’ non-quadratic multipliers. The Petrie multipliers span a full spectrum of behaviors which we classify into four universal types. A variation of the stochastic Poisson model and its Petrie multipliers is further applied to the context of cyber warfare.

Fourier series

CERN Document Server

Tolstov, Georgi P

1962-01-01

Richard A. Silverman's series of translations of outstanding Russian textbooks and monographs is well-known to people in the fields of mathematics, physics, and engineering. The present book is another excellent text from this series, a valuable addition to the English-language literature on Fourier series.This edition is organized into nine well-defined chapters: Trigonometric Fourier Series, Orthogonal Systems, Convergence of Trigonometric Fourier Series, Trigonometric Series with Decreasing Coefficients, Operations on Fourier Series, Summation of Trigonometric Fourier Series, Double Fourie

Implementation gap between the theory and practice of biodiversity offset multipliers

DEFF Research Database (Denmark)

Bull, Joseph William; Lloyd, Samuel P.; Strange, Niels

2017-01-01

literature on multipliers. Then, we collate data on multipliers implemented in practice, rep- resenting the most complete such assessment to date. Finally, we explore remaining design gaps relating to social, ethical, and governance considerations. Multiplier values should theoretically be tens or hundreds...... when considering, for example, ecological uncertainties. We propose even larger multipliers required to satisfy previously ignored considerations – including prospect theory, taboo trades, and power relationships. Conversely, our data analyses show that multipliers are smaller in practice, regularly...... for the implementation gap we have identified. At the same time, there is a need to explore when and where the social, ethical, and governance requirements for NNL reviewed here can be met through approaches other than multipliers....

Tables of compound-discount interest rate multipliers for evaluating forestry investments.

Science.gov (United States)

Allen L. Lundgren

1971-01-01

Tables, prepared by computer, are presented for 10 selected compound-discount interest rate multipliers commonly used in financial analyses of forestry investments. Two set of tables are given for each of the 10 multipliers. The first set gives multipliers for each year from 1 to 40 years; the second set gives multipliers at 5-year intervals from 5 to 160 years....

Efek Multiplier Zakat Terhadap Pendapatan di Propinsi DKI Jakarta

Directory of Open Access Journals (Sweden)

M. Nur Rianto Al Arif

2015-10-01

Full Text Available The aim of this research is to analyze the multiplier effect of zakah revenue in DKI Jakarta, a study case at Badan Amil Zakat, Infak, and Shadaqah (BAZIS DKI Jakarta. Least square methods is used to analyze the data. The coefficient will be used to calculate the multiplier effect of zakah revenue and it will be compared with the economy without zakah revenue. The result showed 2,522 multiplier effects of zakah revenue and 3,561 multiplier effect of economic income without zakah revenue. This suggest that the management of zakah in BAZIS DKI Jakarta still can have a significant influence on the economyDOI: 10.15408/aiq.v4i1.2079

Microchannel electron multiplier

International Nuclear Information System (INIS)

Beranek, I.; Janousek, L.; Vitovsky, O.

1981-01-01

A microchannel electron multiplier is described for detecting low levels of alpha, beta, soft X-ray and UV radiations. It consists of a glass tube or a system of tubes of various shapes made of common technological glass. The inner tube surface is provided with an active coat with photoemitter and secondary emitter properties. (B.S.)

EFEK MULTIPLIER ZAKAT TERHADAP PENDAPATAN DI PROVINSI DKI JAKARTA

Directory of Open Access Journals (Sweden)

M. Nur Rianto Al Arif

2016-02-01

Full Text Available The aim of this research is to analyse the multiplier effect of zakâh revenue in DKI Jakarta. A study case at Badan Amil Zakat, Infak, and Sadaqah (BAZIS DKI Jakarta. Least square method is used to analyze the data. The coefficients will be used to calculate the multiplier effect of zakâh-revenue and it will  be compared with the economy without zakah revenue. The results showed 2,522 multiplier effects of zakâh-revenue and 3.561 multiplier effect ofeconomic income without zakâh-revenue. This suggests that the management of zakat in BAZIS Jakarta still can have a significant influence on the economy.DOI: 10.15408/aiq.v4i1.2533

Multiplier convergent series and uniform convergence of mapping ...

Indian Academy of Sciences (India)

MS received 14 April 2011; revised 17 November 2012. Abstract. In this paper, we introduce the frame property of complex sequence sets and study the uniform convergence of nonlinear mapping series in β-dual of spaces consisting of multiplier convergent series. Keywords. Multiplier convergent series; mapping series. 1.

Temperature Insensitive Current-Mode Four Quadrant Multiplier Using Single CFCTA

Directory of Open Access Journals (Sweden)

Tuntrakool Sunti

2017-01-01

Full Text Available A four quadrant multiplier of two current input signals using active building block, namely current follower cascaded transconductance amplifier (CFCTA is presented in this paper. The proposed multiplier consists of only single CFCTA without the use of any passive element. The presented circuit has low impedance at current input node and high impedance at current output node which is convenient for cascading in current mode circuit without the need of current buffer circuits. The output current can multiply two input currents with temperature insensitivity. Moreover, the magnitude of output current can be controlled electronically via DC bias current. With only single active building block, the presented multiplier is suitable for integrated circuit implementation for analog signal processing. Simulation results from a PSpice program are presented in order to demonstrate the multiplier proposed here.

Cavallo's multiplier for in situ generation of high voltage

Science.gov (United States)

Clayton, S. M.; Ito, T. M.; Ramsey, J. C.; Wei, W.; Blatnik, M. A.; Filippone, B. W.; Seidel, G. M.

2018-05-01

A classic electrostatic induction machine, Cavallo's multiplier, is suggested for in situ production of very high voltage in cryogenic environments. The device is suitable for generating a large electrostatic field under conditions of very small load current. Operation of the Cavallo multiplier is analyzed, with quantitative description in terms of mutual capacitances between electrodes in the system. A demonstration apparatus was constructed, and measured voltages are compared to predictions based on measured capacitances in the system. The simplicity of the Cavallo multiplier makes it amenable to electrostatic analysis using finite element software, and electrode shapes can be optimized to take advantage of a high dielectric strength medium such as liquid helium. A design study is presented for a Cavallo multiplier in a large-scale, cryogenic experiment to measure the neutron electric dipole moment.

A cascaded three-phase symmetrical multistage voltage multiplier

International Nuclear Information System (INIS)

Iqbal, Shahid; Singh, G K; Besar, R; Muhammad, G

2006-01-01

A cascaded three-phase symmetrical multistage Cockcroft-Walton voltage multiplier (CW-VM) is proposed in this report. It consists of three single-phase symmetrical voltage multipliers, which are connected in series at their smoothing columns like string of batteries and are driven by three-phase ac power source. The smoothing column of each voltage multiplier is charged twice every cycle independently by respective oscillating columns and discharged in series through load. The charging discharging process completes six times a cycle and therefore the output voltage ripple's frequency is of sixth order of the drive signal frequency. Thus the proposed approach eliminates the first five harmonic components of load generated voltage ripples and sixth harmonic is the major ripple component. The proposed cascaded three-phase symmetrical voltage multiplier has less than half the voltage ripple, and three times larger output voltage and output power than the conventional single-phase symmetrical CW-VM. Experimental and simulation results of the laboratory prototype are given to show the feasibility of proposed cascaded three-phase symmetrical CW-VM

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.

Multiplier Accounting of Indian Mining Industry: The Application

Science.gov (United States)

Hussain, Azhar; Karmakar, Netai Chandra

2017-10-01

In the previous paper (Hussain and Karmakar in Inst Eng India Ser, 2014. doi: 10.1007/s40033-014-0058-0), the concepts of input-output transaction matrix and multiplier were explained in detail. Input-output multipliers are indicators used for predicting the total impact on an economy due to changes in its industrial demand and output which is calculated using transaction matrix. The aim of this paper is to present an application of the concepts with respect to the mining industry, showing progress in different sectors of mining with time and explaining different outcomes from the results obtained. The analysis shows that a few mineral industries saw a significant growth in their multiplier values over the years.

Production processes of multiply charged ions by electron impact

International Nuclear Information System (INIS)

Oda, Nobuo

1980-02-01

First, are compared the foil or gas stripper and the ion sources utilizing electron-atom ionizing collisions, which are practically used or are under development to produce multiply charged ions. A review is made of the fundamental physical parameters such as successive ionization potentials and various ionization cross sections by electron impact, as well as the primary processes in multiply charged ion production. Multiply charged ion production processes are described for the different existing ion sources such as high temperature plasma type, ion-trapping type and discharge type. (author)

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.

The Multiply Handicapped Child.

Science.gov (United States)

Wolf, James M., Ed.; Anderson, Robert M., Ed.

Articles presented in the area of the medical and educational challenge of the multiply handicapped child are an overview of the problem, the increasing challenge, congenital malformations, children whose mothers had rubella, prematurity and deafness, the epidemiology of reproductive casualty, and new education for old problems. Discussions of…

Fourier phase in Fourier-domain optical coherence tomography

Science.gov (United States)

Uttam, Shikhar; Liu, Yang

2015-01-01

Phase of an electromagnetic wave propagating through a sample-of-interest is well understood in the context of quantitative phase imaging in transmission-mode microscopy. In the past decade, Fourier-domain optical coherence tomography has been used to extend quantitative phase imaging to the reflection-mode. Unlike transmission-mode electromagnetic phase, however, the origin and characteristics of reflection-mode Fourier phase are poorly understood, especially in samples with a slowly varying refractive index. In this paper, the general theory of Fourier phase from first principles is presented, and it is shown that Fourier phase is a joint estimate of subresolution offset and mean spatial frequency of the coherence-gated sample refractive index. It is also shown that both spectral-domain phase microscopy and depth-resolved spatial-domain low-coherence quantitative phase microscopy are special cases of this general theory. Analytical expressions are provided for both, and simulations are presented to explain and support the theoretical results. These results are further used to show how Fourier phase allows the estimation of an axial mean spatial frequency profile of the sample, along with depth-resolved characterization of localized optical density change and sample heterogeneity. Finally, a Fourier phase-based explanation of Doppler optical coherence tomography is also provided. PMID:26831383

Fourier phase in Fourier-domain optical coherence tomography.

Science.gov (United States)

Uttam, Shikhar; Liu, Yang

2015-12-01

Phase of an electromagnetic wave propagating through a sample-of-interest is well understood in the context of quantitative phase imaging in transmission-mode microscopy. In the past decade, Fourier-domain optical coherence tomography has been used to extend quantitative phase imaging to the reflection-mode. Unlike transmission-mode electromagnetic phase, however, the origin and characteristics of reflection-mode Fourier phase are poorly understood, especially in samples with a slowly varying refractive index. In this paper, the general theory of Fourier phase from first principles is presented, and it is shown that Fourier phase is a joint estimate of subresolution offset and mean spatial frequency of the coherence-gated sample refractive index. It is also shown that both spectral-domain phase microscopy and depth-resolved spatial-domain low-coherence quantitative phase microscopy are special cases of this general theory. Analytical expressions are provided for both, and simulations are presented to explain and support the theoretical results. These results are further used to show how Fourier phase allows the estimation of an axial mean spatial frequency profile of the sample, along with depth-resolved characterization of localized optical density change and sample heterogeneity. Finally, a Fourier phase-based explanation of Doppler optical coherence tomography is also provided.

Integrated optic vector-matrix multiplier

Science.gov (United States)

Watts, Michael R [Albuquerque, NM

2011-09-27

A vector-matrix multiplier is disclosed which uses N different wavelengths of light that are modulated with amplitudes representing elements of an N.times.1 vector and combined to form an input wavelength-division multiplexed (WDM) light stream. The input WDM light stream is split into N streamlets from which each wavelength of the light is individually coupled out and modulated for a second time using an input signal representing elements of an M.times.N matrix, and is then coupled into an output waveguide for each streamlet to form an output WDM light stream which is detected to generate a product of the vector and matrix. The vector-matrix multiplier can be formed as an integrated optical circuit using either waveguide amplitude modulators or ring resonator amplitude modulators.

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.

Multiplier less high-speed squaring circuit for binary numbers

Science.gov (United States)

Sethi, Kabiraj; Panda, Rutuparna

2015-03-01

The squaring operation is important in many applications in signal processing, cryptography etc. In general, squaring circuits reported in the literature use fast multipliers. A novel idea of a squaring circuit without using multipliers is proposed in this paper. Ancient Indian method used for squaring decimal numbers is extended here for binary numbers. The key to our success is that no multiplier is used. Instead, one squaring circuit is used. The hardware architecture of the proposed squaring circuit is presented. The design is coded in VHDL and synthesised and simulated in Xilinx ISE Design Suite 10.1 (Xilinx Inc., San Jose, CA, USA). It is implemented in Xilinx Vertex 4vls15sf363-12 device (Xilinx Inc.). The results in terms of time delay and area is compared with both modified Booth's algorithm and squaring circuit using Vedic multipliers. Our proposed squaring circuit seems to have better performance in terms of both speed and area.

Fourier-Hermite communications; where Fourier meets Hermite

NARCIS (Netherlands)

Korevaar, C.W.; Kokkeler, Andre B.J.; de Boer, Pieter-Tjerk; Smit, Gerardus Johannes Maria

A new signal set, based on the Fourier and Hermite signal bases, is introduced. It combines properties of the Fourier basis signals with the perfect time-frequency localization of the Hermite functions. The signal set is characterized by both a high spectral efficiency and good time-frequency

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

An image hiding method based on cascaded iterative Fourier transform and public-key encryption algorithm

Science.gov (United States)

Zhang, B.; Sang, Jun; Alam, Mohammad S.

2013-03-01

An image hiding method based on cascaded iterative Fourier transform and public-key encryption algorithm was proposed. Firstly, the original secret image was encrypted into two phase-only masks M1 and M2 via cascaded iterative Fourier transform (CIFT) algorithm. Then, the public-key encryption algorithm RSA was adopted to encrypt M2 into M2' . Finally, a host image was enlarged by extending one pixel into 2×2 pixels and each element in M1 and M2' was multiplied with a superimposition coefficient and added to or subtracted from two different elements in the 2×2 pixels of the enlarged host image. To recover the secret image from the stego-image, the two masks were extracted from the stego-image without the original host image. By applying public-key encryption algorithm, the key distribution was facilitated, and also compared with the image hiding method based on optical interference, the proposed method may reach higher robustness by employing the characteristics of the CIFT algorithm. Computer simulations show that this method has good robustness against image processing.

Electronic de-multipliers II (ring-shape systems)

International Nuclear Information System (INIS)

Raievski, V.

1948-09-01

This report describes a new type of ring-shape fast electronic counter (de-multiplier) with a resolution capacity equivalent to the one made by Regener (Rev. of Scientific Instruments USA 1946, 17, 180-89) but requiring two-times less electronic valves. This report follows the general description of electronic de-multipliers made by J. Ailloud (CEA--001). The ring comprises 5 flip-flop circuits with two valves each. The different elements of the ring are calculated with enough details to allow the transfer of this calculation to different valve types. (J.S.)

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

Suppressing carrier removal error in the Fourier transform method for interferogram analysis

International Nuclear Information System (INIS)

Fan, Qi; Yang, Hongru; Li, Gaoping; Zhao, Jianlin

2010-01-01

A new carrier removal method for interferogram analysis using the Fourier transform is presented. The proposed method can be used to suppress the carrier removal error as well as the spectral leakage error. First, the carrier frequencies are estimated with the spectral centroid of the up sidelobe of the apodized interferogram, and then the up sidelobe can be shifted to the origin in the frequency domain by multiplying the original interferogram by a constructed plane reference wave. The influence of the carrier frequencies without an integer multiple of the frequency interval and the window function for apodization of the interferogram can be avoided in our work. The simulation and experimental results show that this method is effective for phase measurement with a high accuracy from a single interferogram

Dark energy from modified gravity with Lagrange multipliers

International Nuclear Information System (INIS)

Capozziello, Salvatore; Matsumoto, Jiro; Nojiri, Shin'ichi; Odintsov, Sergei D.

2010-01-01

We study scalar-tensor theory, k-essence and modified gravity with Lagrange multiplier constraint which role is to reduce the number of degrees of freedom. Dark Energy cosmology of different types (ΛCDM, unified inflation with DE, smooth non-phantom/phantom transition epoch) is reconstructed in such models. It is demonstrated that presence of Lagrange multiplier simplifies the reconstruction scenario. It is shown that mathematical equivalence between scalar theory and F(R) gravity is broken due to presence of constraint. The cosmological evolution is defined by the second F 2 (R) function dictated by the constraint. The convenient F(R) gravity sector is relevant for local tests. This opens the possibility to make originally non-realistic theory to be viable by adding the corresponding constraint. A general discussion on the role of Lagrange multipliers to make higher-derivative gravity canonical is developed.

Principal parameters of classical multiply charged ion sources

International Nuclear Information System (INIS)

Winter, H.; Wolf, B.H.

1974-01-01

A review is given of the operational principles of classical multiply charged ion sources (operating sources for intense beams of multiply charged ions using discharge plasmas; MCIS). The fractional rates of creation of multiply charged ions in MCIS plasmas cannot be deduced from the discharge parameters in a simple manner; they depend essentially on three principal parameters, the density and energy distribution of the ionizing electrons, and the confinement time of ions in the ionization space. Simple discharge models were used to find relations between principal parameters, and results of model calculations are compared to actually measured charge state density distributions of extracted ions. Details of processes which determine the energy distribution of ionizing electrons (heating effects), confinement times of ions (instabilities), and some technical aspects of classical MCIS (cathodes, surface processes, conditioning, life time) are discussed

Dimension of the c-nilpotent multiplier of Lie algebras

Indian Academy of Sciences (India)

Abstract. The purpose of this paper is to derive some inequalities for dimension of the c-nilpotent multiplier of finite dimensional Lie algebras and their factor Lie algebras. We further obtain an inequality between dimensions of c-nilpotent multiplier of Lie algebra L and tensor product of a central ideal by its abelianized factor ...

Tourism multipliers in the Mexican economy

Directory of Open Access Journals (Sweden)

Antonio Kido-Cruz

2016-12-01

Full Text Available This paper presents an analysis of the multiplier impact generated by the tourism sector in Mexico in the year 2013. The importance of studying this sector, in particular, lies in its contribution to the National GDP of over 8% and in its promising development based on services’ quality and the preferred destination of the developed countries. In addition, it is proposed to simulate the multiplier impact that will generate two current events, as they are, the construction of the new International Airport of Mexico and the increase of the investment in Fibers. The results were very punctual, a better distribution of the investment is generated, it is invested in the tourism sector, mainly in variables such as value added and remuneration.

Effect of the equity multiplier indicator in companies according the sectors

Directory of Open Access Journals (Sweden)

Lenka Lízalová

2013-01-01

Full Text Available Managers carry out the demand of the owners to maximise the rentability of invested capital with regards to the taken risk. The tool that evaluates the suitability to indebt in order to reach a higher rentability is the equity multiplier indicator. An analysis of the multiplier was carried out on 10 years of data from 456 Czech companies. Based on the data from these companies the influence of two components of the multiplier, which characterise the influence of indebtedness on the return on equity, was analysed. These components are “financial leverage” and “interest burden”, these having an antagonistic effect. The low variability of the equity multiplier is apparent in the companies of the administrative and support service sector and it is also relatively low in the companies of the agriculture, forestry and fishing sector; on the contrary, in for example the professional, scientific and technical activities and the sector of water, sewage and waste there are companies with higher variability of the equity multiplier. The paper identifies companies (in view of their sector specialization inclining to a larger utility of debts to increase the return on equity. The largest equity is reached in companies of the construction sector; the lowest effect of the multiplier is to be found in companies of the agriculture sector. The resulting value of the multiplier is to a large extent determined by the financial leverage indicator, to a lower extent and at the same time negatively by the interest burden indicator.

Physics of subcritical multiplying regions and experimental validation

International Nuclear Information System (INIS)

Salvatores, M.

1996-01-01

The coupling of a particle accelerator with a spallation target and with a subcritical multiplying region has been proposed in the fifties and is called here a hybrid system. This article gives some ideas about the energetic balance of such a system. The possibilities of experimental validation of some properties of a subcritical multiplying region by using MASURCA facility at CEA-Cadarache are examined. The results of a preliminary experiment called MUSE are presented. (A.C.)

Multiply charged ions from solid substances with the mVINIS Ion Source

International Nuclear Information System (INIS)

Dragani, I; Nedeljkovi, T; Jovovi, J; Siljegovic, M; Dobrosavljevic, A

2007-01-01

We have used the well known metal-ions-from-volatile-compounds (MIVOC) method at the mVINIS Ion Source to produce the multiply charged ion beams form solid substances. Based on this method the very intense and stable multiply charged ion beams of several solid substances having the high melting points were extracted. The ion yields and the spectra of multiply charged ion beams obtained from solid materials like Fe and Hf will be presented. We have utilized the multiply charged ion beams from solid substances to irradiate the polymers, fullerenes and glassy carbon at the low energy channel for modification of materials

Why Multiply by "g"?

Science.gov (United States)

Nelson, Jane Bray

2012-01-01

As a new physics teacher, I was explaining how to find the weight of an object sitting on a table near the surface of the Earth. It bothered me when a student asked, "The object is not accelerating so why do you multiply the mass of the object by the acceleration due to gravity?" I answered something like, "That's true, but if the table were not…

Lagrangian relaxation technique in power systems operation planning: Multipliers updating problem

Energy Technology Data Exchange (ETDEWEB)

Ruzic, S. [Electric Power Utility of Serbia, Belgrade (Yugoslavia)

1995-11-01

All Lagrangian relaxation based approaches to the power systems operation planning have an important common part: the Lagrangian multipliers correction procedure. It is the subject of this paper. Different approaches presented in the literature are discussed and an original method for the Lagrangian multipliers updating is proposed. The basic idea of this new method is to update Lagrangian multipliers trying to satisfy Khun-Tucker optimality conditions. Instead of the dual function maximization the `distance of optimality function` is defined and minimized. If Khun-Tucker optimality conditions are satisfied the value of this function is in range (-1,0); otherwise the function has a big positive value. This method called `the distance of optimality method` takes into account future changes in planning generations due to the Lagrangian multipliers updating. The influence of changes in a multiplier associated to one system constraint to the satisfaction of some other system requirements is also considered. The numerical efficiency of the proposed method is analyzed and compared with results obtained using the sub-gradient technique. 20 refs, 2 tabs

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.

Deflation Expectation Financial System and Decline in Money Multiplier(in Japanese)

OpenAIRE

IIDA Yasuyuki

2005-01-01

The money multiplier is in a continuous downward trend now since the bubble burst, and, in addition, the trend has accelerated after 2000. It is said that the monetary policy is difficult because the money multiplier has declined. To think about the monetary policy for the future, we should think about the cause of the decline of the money multiplier. I want to verify two typical hypotheses "Deflation Expectation Hypothesis" and "Financial System Hypothesis" for the decision of the money mult...

Semigroups of Herz-Schur multipliers

DEFF Research Database (Denmark)

Knudby, Søren

2014-01-01

function (see Theorem 1.2). It is then shown that a (not necessarily proper) generator of a semigroup of Herz–Schur multipliers splits into a positive definite kernel and a conditionally negative definite kernel. We also show that the generator has a particularly pleasant form if and only if the group...

Multiplied Environmental Literacy. Final Report.

Science.gov (United States)

Buethe, Chris

This booklet presents a pupil-oriented program designed to increase the environmental literacy of teachers and students in Indiana schools through a programmed multiplier effect. Junior and senior high school science teachers were prepared to teach students the meanings of 44 selected environmental terms and related concepts. Those teachers then…

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 ...

Neutron density decay constant in a non-multiplying lattice of finite size

International Nuclear Information System (INIS)

Deniz, V.C.

1965-01-01

This report presents a general theory, using the integral transport method, for obtaining the neutron density decay constant in a finite non-multiplying lattice. The theory is applied to obtain the expression for the diffusion coefficient. The case of a homogeneous medium with 1/v absorption and of finite size in all directions is treated in detail, assuming an isotropic scattering law. The decay constant is obtained up to the B 6 term. The expressions for the diffusion coefficient and for the diffusion cooling coefficient are the same as those obtained for a slab geometry by Nelkin, using the expansion in spherical harmonics of the Fourier transform in the spatial variable. Furthermore, explicit forms are obtained for the flux and the current. It is shown that the deviation of the actual flux from a Maxwellian is the flux generated in the medium, extended to infinity and deprived of its absorbing power, by various sources, each of which has a zero integral over all velocities. The study of the current permits the generalization of Fick's law. An independent integral method, valid for homogeneous media, is also presented. (author) [fr

Effect of the channel electron multiplier connection diagram on its parameters

International Nuclear Information System (INIS)

Ajnbund, M.R.

1976-01-01

Basic alternatives of connection of a channel electron multiplier are described. A dependence of a gain factor and amplitude resolution of the channel electron multiplier upon its connection diagram is studied. The studies have shown that the maximum gain factor is typical of an open-output circuit where the signal is recorded from the anode of the channel electron multiplier at a potential with respect to the channel outlet. The highest amplitude resolution is inherent in a separate-anode circuit where the loading resistance is connected directly to the channel outlet

Fiscal Multipliers in Ukraine

OpenAIRE

Pritha Mitra; Tigran Poghosyan

2015-01-01

Amid renewed crisis, falling tax revenues, and rising debt, Ukraine faces serious fiscal consolidation needs. Durable fiscal adjustment can support economic confidence and rebuild buffers but what is its overall impact on growth? How effective are revenue versus spending instruments? Does current or capital spending have a larger impact? Applying a structural vector autoregressive model, this paper finds that Ukraine’s near-term revenue and spending multipliers are well below one. In the medi...

Karatsuba-Ofman Multiplier with Integrated Modular Reduction for GF(2m

Directory of Open Access Journals (Sweden)

CUEVAS-FARFAN, E.

2013-05-01

Full Text Available In this paper a novel GF(2m multiplier based on Karatsuba-Ofman Algorithm is presented. A binary field multiplication in polynomial basis is typically viewed as a two steps process, a polynomial multiplication followed by a modular reduction step. This research proposes a modification to the original Karatsuba-Ofman Algorithm in order to integrate the modular reduction inside the polynomial multiplication step. Modular reduction is achieved by using parallel linear feedback registers. The new algorithm is described in detail and results from a hardware implementation on FPGA technology are discussed. The hardware architecture is described in VHDL and synthesized for a Virtex-6 device. Although the proposed field multiplier can be implemented for arbitrary finite fields, the targeted finite fields are recommended for Elliptic Curve Cryptography. Comparing other KOA multipliers, our proposed multiplier uses 36% less area resources and improves the maximum delay in 10%.

Techniques for computing the discrete Fourier transform using the quadratic residue Fermat number systems

Science.gov (United States)

Truong, T. K.; Chang, J. J.; Hsu, I. S.; Pei, D. Y.; Reed, I. S.

1986-01-01

The complex integer multiplier and adder over the direct sum of two copies of finite field developed by Cozzens and Finkelstein (1985) is specialized to the direct sum of the rings of integers modulo Fermat numbers. Such multiplication over the rings of integers modulo Fermat numbers can be performed by means of two integer multiplications, whereas the complex integer multiplication requires three integer multiplications. Such multiplications and additions can be used in the implementation of a discrete Fourier transform (DFT) of a sequence of complex numbers. The advantage of the present approach is that the number of multiplications needed to compute a systolic array of the DFT can be reduced substantially. The architectural designs using this approach are regular, simple, expandable and, therefore, naturally suitable for VLSI implementation.

Development of a positive column pulsed capillary discharge source for use with high resolution Fourier transform spectrometer

International Nuclear Information System (INIS)

Syed, W A A

2002-01-01

We report the designing and application of a positive column pulsed capillary discharge with the Fourier transform spectrometer (FTS). The pulsed light source has been used for the first time with the ultraviolet FTS. The experiment has been carried out with the high energy pulsed discharge with energy of 2-3 J lasting about 300 ns. A system has been developed to trigger the discharge at about 600 Hz with the pulses directly taken from the FTS sampling system. The spectrum of Ar III has been recorded in the 19 000-50 000 cm -1 region with good signal to noise ratio. The results have opened a wide range of applications in spectroscopy of multiply ionized species

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.

The evolution of unconditional strategies via the 'multiplier effect'.

Science.gov (United States)

McNamara, John M; Dall, Sasha R X

2011-03-01

Ostensibly, it makes sense in a changeable world to condition behaviour and development on information when it is available. Nevertheless, unconditional behavioural and life history strategies are widespread. Here, we show how intergenerational effects can limit the evolutionary value of responding to reliable environmental cues, and thus favour the evolutionary persistence of otherwise paradoxical unconditional strategies. While cue-ignoring genotypes do poorly in the wrong environments, in the right environment they will leave many copies of themselves, which will themselves leave many copies, and so on, leading genotypes to accumulate in habitats in which they do well. We call this 'The Multiplier Effect'. We explore the consequences of the multiplier effect by focussing on the ecologically important phenomenon of natal philopatry. We model the environment as a large number of temporally varying breeding sites connected by natal dispersal between sites. Our aim is to identify which aspects of an environment promote the multiplier effect. We show, if sites remain connected through some background level of 'accidental' dispersal, unconditional natal philopatry can evolve even when there is density dependence (with its accompanying kin competition effects), and cues that are only mildly erroneous. Thus, the multiplier effect may underpin the evolution and maintenance of unconditional strategies such as natal philopatry in many biological systems. © 2011 Blackwell Publishing Ltd/CNRS.

The long-run relationship between the Japanese credit and money multipliers

OpenAIRE

Mototsugu Fukushige

2013-01-01

The standard argument is that while money creation and credit creation have different channels, they provide the same theoretical size of multipliers. However, there is usually some difference in practice. Consequently, in this paper we investigate the long-run relationship between the credit and money multipliers in Japan.

The generalization of the Schur multipliers of Bieberbach groups

Science.gov (United States)

Masri, Rohaidah; Hassim, Hazzirah Izzati Mat; Sarmin, Nor Haniza; Ali, Nor Muhainiah Mohd; Idrus, Nor'ashiqin Mohd

2014-12-01

The Schur multiplier is the second homology group of a group. It has been found to be isomorphic to the kernel of a homomorphism which maps the elements in the exterior square of the group to the elements in its derived subgroup. Meanwhile, a Bieberbach group is a space group which is a discrete cocompact group of isometries of oriented Euclidean space. In this research, the Schur multipliers of Bieberbach groups with cyclic point group of order two of finite dimension are computed.

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.

An Application of Multiplier Analysis in Analyzing the Role of Mining Sectors on Indonesian National Economy

Science.gov (United States)

Subanti, S.; Hakim, A. R.; Hakim, I. M.

2018-03-01

This purpose of the current study aims is to analyze the multiplier analysis on mining sector in Indonesia. The mining sectors defined by coal and metal; crude oil, natural gas, and geothermal; and other mining and quarrying. The multiplier analysis based from input output analysis, this divided by income multiplier and output multiplier. This results show that (1) Indonesian mining sectors ranked 6th with contribute amount of 6.81% on national total output; (2) Based on total gross value added, this sector contribute amount of 12.13% or ranked 4th; (3) The value from income multiplier is 0.7062 and the value from output multiplier is 1.2426.

New design of an RSFQ parallel multiply-accumulate unit

International Nuclear Information System (INIS)

Kataeva, Irina; Engseth, Henrik; Kidiyarova-Shevchenko, Anna

2006-01-01

The multiply-accumulate unit (MAC) is a central component of a successive interference canceller, an advanced receiver for W-CDMA base stations. A 4 x 4 two's complement fixed point RSFQ MAC with rounding to 5 bits has been simulated using VHDL, and maximum performance is equal to 24 GMACS (giga-multiply-accumulates per second). The clock distribution network has been re-designed from a linear ripple to a binary tree network in order to eliminate the data dependence of the clock propagation speed and reduce the number of Josephson junctions in clock lines. The 4 x 4 bit MAC has been designed for the HYPRES 4.5 kA cm -2 process and its components have been experimentally tested at low frequency: the 5-bit combiner, using an exhaustive test pattern, had margins on DC bias voltage of ± 18%, and the 4 x 4 parallel multiplier had margins equal to ± 2%

Multiplying Money

Directory of Open Access Journals (Sweden)

Garry Jacobs

2013-05-01

Full Text Available This article is not a comprehensive factual history of money as an economic instrument. It aims rather to present an essential psychological history of the power of money as a social organization or social technology. It explores the catalytic role of money in the development of society and its ever-increasing capacity for accomplishment in both economic and non-economic fields. This perspective focuses attention on the unutilized potential for harnessing the social power of money for promoting full employment, global development and human welfare. The title ‘multiplying money’ is intended to convey the idea that this untapped potential is exponential in nature. In order to recognize it, some fundamental misconceptions about the nature of money, how it is created and on what it is based need to be examined. This is the second article in a series.

Equations for the stochastic cumulative multiplying chain

Energy Technology Data Exchange (ETDEWEB)

Lewins, J D [Cambridge Univ. (UK). Dept. of Engineering

1980-01-01

The forward and backward equations for the conditional probability of the neutron multiplying chain are derived in a new generalization accounting for the chain length and admitting time dependent properties. These Kolmogorov equations form the basis of a variational and hence complete description of the 'lumped' multiplying system. The equations reduce to the marginal distribution, summed over all chain lengths, and to the simpler equations previously derived for that problem. The method of derivation, direct and in the probability space with the minimum of mathematical manipulations, is perhaps the chief attraction: the equations are also displayed in conventional generating function form. As such, they appear to apply to number of problems in areas of social anthropology, polymer chemistry, genetics and cell biology as well as neutron reactor theory and radiation damage.

Equations for the stochastic cumulative multiplying chain

International Nuclear Information System (INIS)

Lewins, J.D.

1980-01-01

The forward and backward equations for the conditional probability of the neutron multiplying chain are derived in a new generalization accounting for the chain length and admitting time dependent properties. These Kolmogorov equations form the basis of a variational and hence complete description of the 'lumped' multiplying system. The equations reduce to the marginal distribution, summed over all chain lengths, and to the simpler equations previously derived for that problem. The method of derivation, direct and in the probability space with the minimum of mathematical manipulations, is perhaps the chief attraction: the equations are also displayed in conventional generating function form. As such, they appear to apply to number of problems in areas of social anthropology, polymer chemistry, genetics and cell biology as well as neutron reactor theory and radiation damage. (author)

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.

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...

Enhancing shelf life of minimally processed multiplier onion using silicone membrane.

Science.gov (United States)

Naik, Ravindra; Ambrose, Dawn C P; Raghavan, G S Vijaya; Annamalai, S J K

2014-12-01

The aim of storage of minimal processed product is to increase the shelf life and thereby extend the period of availability of minimally processed produce. The silicone membrane makes use of the ability of polymer to permit selective passage of gases at different rates according to their physical and chemical properties. Here, the product stored maintains its own atmosphere by the combined effects of respiration process of the commodity and the diffusion rate through the membrane. A study was undertaken to enhance the shelf life of minimally processed multiplier onion with silicone membrane. The respiration activity was recorded at a temperature of 30 ± 2 °C (RH = 60 %) and 5 ± 1 °C (RH = 90 %). The respiration was found to be 23.4, 15.6, 10 mg CO2kg(-1)h(-1) at 5 ± 1 °C and 140, 110, 60 mg CO2kg(-1) h(-1) at 30 ± 2° for the peeled, sliced and diced multiplier onion, respectively. The respiration rate for the fresh multiplier onion was recorded to be 5, 10 mg CO2kg(-1) h(-1) at 5 ± 1 °C and 30 ± 1 ° C, respectively. Based on the shelf life studies and on the sensory evaluation, it was found that only the peeled multiplier onion could be stored. The sliced and diced multiplier onion did not have the required shelf life. The shelf life of the multiplier onion in the peel form could be increased from 4-5 days to 14 days by using the combined effect of silicone membrane (6 cm(2)/kg) and low temperature (5 ± 1 °C).

Private Debt Overhang and the Government Spending Multiplier: Evidence for the United States

OpenAIRE

Bernardini, Marco; Peersman, Gert

2015-01-01

Using state-dependent local projection methods and historical U.S. data, we find that government spending multipliers are considerably larger in periods of private debt overhang. In particular, we find significant crowding-out of personal consumption and investment in low-debt states, resulting in multipliers that are significantly below one. Conversely, in periods of private debt overhang, there is a strong crowding-in effect, while multipliers are much larger than one. In high-debt states, ...

On centralized power pool auction: a novel multipliers stabilization procedure

International Nuclear Information System (INIS)

Jimenez-Redondo, Noemi

2005-01-01

This paper addresses the Short-Term Hydro-Thermal Coordination (STHTC) problem. It is a large-scale, combinatorial and nonlinear optimization problem. It is usually solved using a Lagrangian Relaxation (LR) approach. LR procedure is based on the solution of the dual problem of the original one. The dual problem variables are the Lagrange multipliers. These multipliers have an economic meaning: electric energy hourly prices. This paper focuses on an efficient solution of the dual problem of the STHTC problem. A novel multiplier stabilization technique, which significantly improves the quality of the solution, is presented. The provided method could be the optimization tool used by the Independent System Operator of a centralized Power Pool. The solution procedure diminishes the conflict of interest in determining energy prices. A realistic large-scale case study illustrates the behavior of the presented approach. (Author)

Study on neutron irradiation behavior of beryllium as neutron multiplier

Energy Technology Data Exchange (ETDEWEB)

Ishitsuka, Etsuo [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment

1998-03-01

More than 300 tons beryllium is expected to be used as a neutron multiplier in ITER, and study on the neutron irradiation behavior of beryllium as the neutron multiplier with Japan Materials Testing Reactor (JMTR) were performed to get the engineering data for fusion blanket design. This study started as the study on the tritium behavior in beryllium neutron reflector in order to make clear the generation mechanism on tritium of JMTR primary coolant since 1985. These experiences were handed over to beryllium studies for fusion study, and overall studies such as production technology of beryllium pebbles, irradiation behavior evaluation and reprocessing technology have been started since 1990. In this presentation, study on the neutron irradiation behavior of beryllium as the neutron multiplier with JMTR was reviewed from the point of tritium release, thermal properties, mechanical properties and reprocessing technology. (author)

KAJIAN EFEK MULTIPLIER PRODUK UNGGULAN BERBASIS KLUSTER UKM PENGOLAHAN IKAN ASAP

Directory of Open Access Journals (Sweden)

Yusmar Ardhi Hidayat

2015-05-01

Full Text Available The purpose of this research are to analyze scale of production of leading commodities and multiplier effect of cultivation and smoked fish in Wonosari, Bonang Demak. This research applies census method in collecting data from all business unit which identified as leading commodities in Wirosari Village, Bonang, Demak Regency. Regarding survey conducted, there are 18 catfish breeders and 49 smoked fish small business used as respondent. Primary data used in this research are rate of production in basis goods, land area, capital, raw materials, manpower, and income multiplier. To support empirical discussion, tools of analysis used in this research are descriptive statistics and income multiplier. Results of this research are primary commodities in Wonosari Village are smoked fish and fresh cat fish. Total production of smoked fish reaches 6.4 Ton each day for with type of smoked fish such as river cat fish, tongkol, sting-ray, cat fish, and other river fish. Meanwhile total production of catfish breeding reaches 105 Ton in first harvest after 2-3 months. Based on that number, smoked fish business promise higher profit than profits catfish breeding. Tujuan penelitian ini adalah menganalisis tingkat produksi dan efek multiplier produk unggulan budidaya dan pengasapan ikan di Desa Wonosari, Bonang Kabupaten Demak. Penelitian mengunakan metode sensus dengan mencari data dari semua unit usaha yang merupakan produk unggulan di Desa Wirosari, Bonang Kecamatan Demak. Responden yang diperoleh sejumlah 18 pembudidaya ikan dan 49 usaha pengasapan ikan. Data primer yang akan digunakan yaitu data jumlah produksi komoditas unggulan, luas lahan, jumlah modal, bahan baku, tenaga kerja, dan multiplier pendapatan. Alat analisis yang digunakan dalam penelitian ini adalah statistik deskriptif, dan indeks multiplier pendapatan. Hasil penelitian menunjukkan bahwa komoditas unggulan Desa Wonosari Kecamatan Bonang Kabupaten Demak adalah Ikan Asap dan Budidaya Ikan Lele

Multiply excited molecules produced by photon and electron interactions

International Nuclear Information System (INIS)

Odagiri, T.; Kouchi, N.

2006-01-01

The photon and electron interactions with molecules resulting in the formation of multiply excited molecules and the subsequent decay are subjects of great interest because the independent electron model and Born-Oppenheimer approximation are much less reliable for the multiply excited states of molecules than for the ground and lower excited electronic states. We have three methods to observe and investigate multiply excited molecules: 1) Measurements of the cross sections for the emission of fluorescence emitted by neutral fragments in the photoexcitation of molecules as a function of incident photon energy [1-3], 2) Measurements of the electron energy-loss spectra tagged with the fluorescence photons emitted by neutral fragments [4], 3) Measurements of the cross sections for generating a pair of photons in absorption of a single photon by a molecule as a function of incident photon energy [5-7]. Multiply excited states degenerate with ionization continua, which make a large contribution in the cross section curve involving ionization processes. The key point of our methods is hence that we measure cross sections free from ionization. The feature of multiply excited states is noticeable in such a cross section curve. Recently we have measured: i) the cross sections for the emission of the Lyman- fluorescence in the photoexcitation of CH 4 as a function of incident photon energy in the range 18-51 eV, ii) the electron energy-loss spectrum of CH 4 tagged with the Lyman-photons at 80 eV incident electron energy and 10 electron scattering angle in the range of the energy loss 20-45 eV, in order to understand the formation and decay of the doubly excited methane in photon and electron interactions. [8] The results are summarized in this paper and the simultaneous excitation of two electrons by electron interaction is compared with that by photon interaction in terms of the oscillator strength. (authors)

Isometric multipliers of a vector valued Beurling algebra on a ...

Indian Academy of Sciences (India)

Throughout, let S be a nonunital faith- ful abelian semigroup, and let A be a commutative Banach algebra. A map σ : S → S is a multiplier [1, 4] if σ(xy) = xσ(y) = σ(x)y, x,y ∈ S. Let M(S) be the set of all multipliers of S. Then M(S) is a unital abelian semigroup under composition. Since S is faithful, S can be imbedded as an ...

Low‐Power and Low‐Hardware Bit‐Parallel Polynomial Basis Systolic Multiplier over GF(2m for Irreducible Polynomials

Directory of Open Access Journals (Sweden)

Sudha Ellison Mathe

2017-08-01

Full Text Available Multiplication in finite fields is used in many applications, especially in cryptography. It is a basic and the most computationally intensive operation from among all such operations. Several systolic multipliers are proposed in the literature that offer low hardware complexity or high speed. In this paper, a bit‐parallel polynomial basis systolic multiplier for generic irreducible polynomials is proposed based on a modified interleaved multiplication method. The hardware complexity and delay of the proposed multiplier are estimated, and a comparison with the corresponding multipliers available in the literature is presented. Of the corresponding multipliers, the proposed multiplier achieves a reduction in the hardware complexity of up to 20% when compared to the best multiplier for m = 163. The synthesis results of application‐specific integrated circuit and field‐programmable gate array implementations of the proposed multiplier are also presented. From the synthesis results, it is inferred that the proposed multiplier achieves low power consumption and low area complexitywhen compared to the best of the corresponding multipliers.

Californium Multiplier. Part I. Design for neutron radiography

International Nuclear Information System (INIS)

Crosbie, K.L.; Preskitt, C.A.; John, J.; Hastings, J.D.

1982-01-01

The Californium Multiplier (CFX) is a subcritical assembly of enriched uranium surrounding a californium-252 neutron source. The function of the CFX is to multiply the neutrons emitted by the source to a number sufficient for neutron radiography. The CFX is designed to provide a collimated beam of thermal neutrons from which the gamma radiation is filtered, and the scattered neutrons are reduced to make it suitable for high resolution radiography. The entire system has inherent safety features, which provide for system and personnel safety, and it operates at moderate cost. In Part I, the CFX and the theory of its operation are described in detail. Part II covers the performance of the Mound Facility CFX

Time efficient signed Vedic multiplier using redundant binary representation

Directory of Open Access Journals (Sweden)

Ranjan Kumar Barik

2017-03-01

Full Text Available This study presents a high-speed signed Vedic multiplier (SVM architecture using redundant binary (RB representation in Urdhva Tiryagbhyam (UT sutra. This is the first ever effort towards extension of Vedic algorithms to the signed numbers. The proposed multiplier architecture solves the carry propagation issue in UT sutra, as carry free addition is possible in RB representation. The proposed design is coded in VHDL and synthesised in Xilinx ISE 14.4 of various FPGA devices. The proposed SVM architecture has better speed performances as compared with various state-of-the-art conventional as well as Vedic architectures.

Radial multipliers on amalgamated free products of II-factors

DEFF Research Database (Denmark)

Möller, Sören

2014-01-01

Let ℳi be a family of II1-factors, containing a common II1-subfactor 풩, such that [ℳi : 풩] ∈ ℕ0 for all i. Furthermore, let ϕ: ℕ0 → ℂ. We show that if a Hankel matrix related to ϕ is trace-class, then there exists a unique completely bounded map Mϕ on the amalgamated free product of the ℳi...... with amalgamation over 풩, which acts as a radial multiplier. Hereby, we extend a result of Haagerup and the author for radial multipliers on reduced free products of unital C*- and von Neumann algebras....

Determination of stress multipliers for thin perforated plates with square array of holes

International Nuclear Information System (INIS)

Bhattacharya, A.; Murli, B.; Kushwaha, H.S.

1991-01-01

The peak stress multipliers are required to determine the maximum stresses in perforated plates for the realistic evaluation of their fatigue life. The Section III of ASME Boiler and Pressure Vessels Code does not provide any information about such multipliers to be used in thin perforated plates with square penetration pattern. Although such multipliers for membrane loadings are available in literature, they were obtained either by classical analysis or by photoelastic experiments and there is no significant finite element analysis in this area. Also it has been a common practice among designers to apply the same multipliers for loads producing bending type of stress. The stress multipliers in bending are lower than those in membrane. Therefore a reduction of resultant peak stress occurs if proper stress multipliers are used for bending. The present paper is aimed at developing a finite element technique which can be used for determining the peak stress multipliers in thin plates for membrane as well as bending loads. A quarter symmetric part of a 3 x 3 square array was chosen for the analysis. The results were obtained by computer programs PAFEC and COSMOS/M using 2-D plane stress elements for the membrane and degenerated 3-D shell element for the bending part. The results for the membrane are compared with Bailey, Hicks and Hulbert and with Meijers' finite element results for the bending part. A study was made at the initial stage by analysing a 6 x 6 square array to see the effect of holes beyond one pitch, which were left out by the 3 x 3 array and the effect of additional holes was found to be negligible. Therefore it was decided to carry out further analysis with 3 x 3 square array. Photoelastic experiments were also performed to validate the results obtained by theoretical analysis. (author)

Investigation of the Decelerating Field of an Electron Multiplier under Negative Ion Impact

DEFF Research Database (Denmark)

Larsen, Elfinn; Kjeldgaard, K.

1973-01-01

The effect of the decelerating field of an electron multiplier towards negative ions was investigated under standard mass spectrometric conditions. Diminishing of this decelerating field by changing of the potential of the electron multiplier increased the overall sensitivity to negative ions...

A quantum architecture for multiplying signed integers

International Nuclear Information System (INIS)

Alvarez-Sanchez, J J; Alvarez-Bravo, J V; Nieto, L M

2008-01-01

A new quantum architecture for multiplying signed integers is presented based on Booth's algorithm, which is well known in classical computation. It is shown how a quantum binary chain might be encoded by its flank changes, giving the final product in 2's-complement representation.

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)

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.

Profile inversion of principal diffusivities through the use of a spatially modulated heating and a Fourier analysis; Inversion des profils des diffusivites principales par l'application d'un chauffage spatialement module et une analyse dans le domaine de Fourier

Energy Technology Data Exchange (ETDEWEB)

Krapez, J.C.; Spagnolo, L. [Politechnique di Bari (Italy); Friess, M. [Deutsches Luft- und Raumfahrtzentrum eV (DLR), Stuttgart (Germany); Maier, H.P. [Stuttgart Univ., MPA (Germany); Neuer, G. [Institut fur Kernenergetik und Energiesysteme, Universitat Stuttgart (Germany)

2003-07-01

The through-thickness thermal diffusivity can be evaluated by the classical flash method. If an homogeneous and extended source is used to irradiate the surface and a thermographic camera is used to monitor the temperature evolution of the opposite side, a map of the through-thickness thermal diffusivity can be obtained in a single experiment and without any contact with the sample under inspection. In order to measure the in-plane thermal diffusivity of a plate-like sample or in one of the principal directions of its plane, a thermal gradient across the plane of the material has to be settled. The ratio of the Fourier transform of temperature at two different spatial frequencies is an exponential function of time multiplied by the diffusivity in the considered principal direction. This can be used to evaluate the diffusivity in an homogenous material. In order to maximize the signal-to-noise ratio, it is better if heat is absorbed over a series of periodic parallel strips (grid flash method). When the material presents a transverse gradient of conductivity, we propose, as a first approach, to perform the Fourier analysis over a sliding window corresponding to one period of the grid pattern. This method allowed us to quantify in situ the diffusivity decrease in a tensile composite sample due to the stress-induced density increase of transverse microcracks. We finally analysed a more rigorous method for transverse conductivity profile inversion. It is based on a perturbation method. The analytical expression of the 'transfer function' between the Fourier transform of the temperature contrast and the Fourier transform of conductivity was established. We validated the proposed inverse technique on simulated and noise-corrupted thermograms. The approach is robust and the simulated profiles are very well resolved. (authors)

A microchannel plate X-ray multiplier with rising-time less than 170 ps

International Nuclear Information System (INIS)

Zhao Shicheng; Ouyang Bin

1987-01-01

The time reponse of a microchannel plate X-ray multiplier has been improved considerably by using a coupling construction of coaxial tapers. The experimental calibration results with laser plasma X-ray source show that the rising-time of the multiplier is less than 170 ps

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)

On the Fourier integral theorem

NARCIS (Netherlands)

Koekoek, J.

1987-01-01

Introduction. In traditional proofs of convergence of Fourier series and of the Fourier integraI theorem basic tools are the theory of Dirichlet integraIs and the Riemann-Lebesgue lemma. Recently CHERNOFF [I) and REoIlEFFER (2) gave new proofs of convergenceof Fourier series which make no use of the

A CMOS four-quadrant analog current multiplier

NARCIS (Netherlands)

Wiegerink, Remco J.

1991-01-01

A CMOS four-quadrant analog current multiplier is described. The circuit is based on the square-law characteristic of an MOS transistor and is insensitive to temperature and process variations. The circuit is insensitive to the body effect so it is not necessary to place transistors in individual

Metasurface Enabled Wide-Angle Fourier Lens.

Science.gov (United States)

Liu, Wenwei; Li, Zhancheng; Cheng, Hua; Tang, Chengchun; Li, Junjie; Zhang, Shuang; Chen, Shuqi; Tian, Jianguo

2018-06-01

Fourier optics, the principle of using Fourier transformation to understand the functionalities of optical elements, lies at the heart of modern optics, and it has been widely applied to optical information processing, imaging, holography, etc. While a simple thin lens is capable of resolving Fourier components of an arbitrary optical wavefront, its operation is limited to near normal light incidence, i.e., the paraxial approximation, which puts a severe constraint on the resolvable Fourier domain. As a result, high-order Fourier components are lost, resulting in extinction of high-resolution information of an image. Other high numerical aperture Fourier lenses usually suffer from the bulky size and costly designs. Here, a dielectric metasurface consisting of high-aspect-ratio silicon waveguide array is demonstrated experimentally, which is capable of performing 1D Fourier transform for a large incident angle range and a broad operating bandwidth. Thus, the device significantly expands the operational Fourier space, benefitting from the large numerical aperture and negligible angular dispersion at large incident angles. The Fourier metasurface will not only facilitate efficient manipulation of spatial spectrum of free-space optical wavefront, but also be readily integrated into micro-optical platforms due to its compact size. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Neutron fluctuations in a multiplying medium randomly varying in time

Energy Technology Data Exchange (ETDEWEB)

Pal, L. [KFKI Atomic Energy Research Inst., Budapest (Hungary); Pazsit, I. [Chalmers Univ. of Technology, Goeteborg (Sweden). Dept. of Nuclear Engineering

2006-07-15

The master equation approach, which has traditionally been used for the calculation of neutron fluctuations in multiplying systems with constant parameters, is extended to a case when the parameters of the system change randomly in time. A forward type master equation is considered for the case of a multiplying system whose properties jump randomly between two discrete states, both with and without a stationary external source. The first two factorial moments are calculated, including the covariance. This model can be considered as the unification of stochastic methods that were used either in a constant multiplying medium via the master equation technique, or in a fluctuating medium via the Langevin technique. The results obtained show a much richer characteristic of the zero power noise than that in constant systems. The results are relevant in medium power subcritical nuclear systems where the zero power noise is still significant, but they also have a bearing on all types of branching processes, such as evolution of biological systems, spreading of epidemics etc, which are set in a time-varying environment.

Neutron fluctuations in a multiplying medium randomly varying in time

International Nuclear Information System (INIS)

Pal, L.; Pazsit, I.

2006-01-01

The master equation approach, which has traditionally been used for the calculation of neutron fluctuations in multiplying systems with constant parameters, is extended to a case when the parameters of the system change randomly in time. A forward type master equation is considered for the case of a multiplying system whose properties jump randomly between two discrete states, both with and without a stationary external source. The first two factorial moments are calculated, including the covariance. This model can be considered as the unification of stochastic methods that were used either in a constant multiplying medium via the master equation technique, or in a fluctuating medium via the Langevin technique. The results obtained show a much richer characteristic of the zero power noise than that in constant systems. The results are relevant in medium power subcritical nuclear systems where the zero power noise is still significant, but they also have a bearing on all types of branching processes, such as evolution of biological systems, spreading of epidemics etc, which are set in a time-varying environment

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)

Atlantic Richfield Hanford Company californium multiplier/delayed neutron counter safety analysis

International Nuclear Information System (INIS)

Zimmer, W.H.

1976-08-01

The Californium Multiplier (CFX) is a subcritical assembly of uranium surrounding 252 Cf spontaneously fissioning neutron sources; its function is to multiply the neutron flux to a level useful for activation analysis. This document summarizes the safety analysis aspects of the CFX, DNC, pneumatic transfer system, and instrumentation and to detail all the aspects of the total facility as a starting point for the ARHCO Safety Analysis Review. Recognized hazards and steps already taken to neutralize them are itemized

Economic Multipliers and Sectoral Linkages: Ghana and the New Oil Sector

Directory of Open Access Journals (Sweden)

Dennis Nchor

2016-01-01

Full Text Available The study seeks to assess the structure of the economy of Ghana in terms of changes in the economic structure before and after the production of oil in commercial quantities. This is viewed with regards to economic multipliers, sectoral interdependence and trade concentration. The results show that changes occurred with regards to multipliers and sectoral interdependence. The output multipliers of most sectors have declined. The results also show that the agricultural sector experienced an initial decline in its growth while industry experienced an increase. The performance of the services sector was relatively stable for the period covered by the study. There is a decline in the level of trade concentration though on a whole the concentration index is still high. The study employed input-output modeling techniques and the data was obtained from the Ghana statistical service and the World Development Indicators.

Fourier analysis an introduction

CERN Document Server

Stein, Elias M

2003-01-01

This first volume, a three-part introduction to the subject, is intended for students with a beginning knowledge of mathematical analysis who are motivated to discover the ideas that shape Fourier analysis. It begins with the simple conviction that Fourier arrived at in the early nineteenth century when studying problems in the physical sciences--that an arbitrary function can be written as an infinite sum of the most basic trigonometric functions.The first part implements this idea in terms of notions of convergence and summability of Fourier series, while highlighting applications such as th

Human reliability under sleep deprivation: Derivation of performance shaping factor multipliers from empirical data

International Nuclear Information System (INIS)

Griffith, Candice D.; Mahadevan, Sankaran

2015-01-01

This paper develops a probabilistic approach that could use empirical data to derive values of performance shaping factor (PSF) multipliers for use in quantitative human reliability analysis (HRA). The proposed approach is illustrated with data on sleep deprivation effects on performance. A review of existing HRA methods reveals that sleep deprivation is not explicitly included at present, and expert opinion is frequently used to inform HRA model multipliers. In this paper, quantitative data from empirical studies regarding the effect of continuous hours of wakefulness on performance measures (reaction time, accuracy, and number of lapses) are used to develop a method to derive PSF multiplier values for sleep deprivation, in the context of the SPAR-H model. Data is extracted from the identified studies according to the meta-analysis research synthesis method and used to investigate performance trends and error probabilities. The error probabilities in test and control conditions are compared, and the resulting probability ratios are suggested for use in informing the selection of PSF multipliers in HRA methods. Although illustrated for sleep deprivation, the proposed methodology is general, and can be applied to other performance shaping factors. - Highlights: • Method proposed to derive performance shaping factor multipliers from empirical data. • Studies reporting the effect of sleep deprivation on performance are analyzed. • Test data using psychomotor vigilance tasks are analyzed. • Error probability multipliers computed for reaction time, lapses, and accuracy measures.

Multiplying dimensions

CERN Multimedia

2013-01-01

A few weeks ago, I had a vague notion of what TED was, and how it worked, but now I’m a confirmed fan. It was my privilege to host CERN’s first TEDx event last Friday, and I can honestly say that I can’t remember a time when I was exposed to so much brilliance in such a short time.   TEDxCERN was designed to give a platform to science. That’s why we called it Multiplying Dimensions – a nod towards the work we do here, while pointing to the broader importance of science in society. We had talks ranging from the most subtle pondering on the nature of consciousness to an eighteen year old researcher urging us to be patient, and to learn from our mistakes. We had musical interludes that included encounters between the choirs of local schools and will.i.am, between an Israeli pianist and an Iranian percussionist, and between Grand Opera and high humour. And although I opened the event by announcing it as a day off from physics, we had a quite brill...

Jean Baptiste Joseph Fourier

Science.gov (United States)

Sterken, C.

2003-03-01

This paper gives a short account of some key elements in the life of Jean Baptiste Joseph Fourier (1768-1830), specifically his relation to Napoleon Bonaparte. The mathematical approach to Fourier series and the original scepticism by French mathematicians are briefly illustrated.

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

Digital Fourier analysis fundamentals

CERN Document Server

Kido, Ken'iti

2015-01-01

This textbook is a thorough, accessible introduction to digital Fourier analysis for undergraduate students in the sciences. Beginning with the principles of sine/cosine decomposition, the reader walks through the principles of discrete Fourier analysis before reaching the cornerstone of signal processing: the Fast Fourier Transform. Saturated with clear, coherent illustrations, "Digital Fourier Analysis - Fundamentals" includes practice problems and thorough Appendices for the advanced reader. As a special feature, the book includes interactive applets (available online) that mirror the illustrations.  These user-friendly applets animate concepts interactively, allowing the user to experiment with the underlying mathematics. For example, a real sine signal can be treated as a sum of clockwise and counter-clockwise rotating vectors. The applet illustration included with the book animates the rotating vectors and the resulting sine signal. By changing parameters such as amplitude and frequency, the reader ca...

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)

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...

A High-Speed Design of Montgomery Multiplier

Science.gov (United States)

Fan, Yibo; Ikenaga, Takeshi; Goto, Satoshi

With the increase of key length used in public cryptographic algorithms such as RSA and ECC, the speed of Montgomery multiplication becomes a bottleneck. This paper proposes a high speed design of Montgomery multiplier. Firstly, a modified scalable high-radix Montgomery algorithm is proposed to reduce critical path. Secondly, a high-radix clock-saving dataflow is proposed to support high-radix operation and one clock cycle delay in dataflow. Finally, a hardware-reused architecture is proposed to reduce the hardware cost and a parallel radix-16 design of data path is proposed to accelerate the speed. By using HHNEC 0.25μm standard cell library, the implementation results show that the total cost of Montgomery multiplier is 130 KGates, the clock frequency is 180MHz and the throughput of 1024-bit RSA encryption is 352kbps. This design is suitable to be used in high speed RSA or ECC encryption/decryption. As a scalable design, it supports any key-length encryption/decryption up to the size of on-chip memory.

Design of a High Linearity Four-Quadrant Analog Multiplier in Wideband Frequency Range

Directory of Open Access Journals (Sweden)

Abdul kareem Mokif Obais

2017-05-01

Full Text Available In this paper, a voltage mode four quadrant analog multiplier in the wideband frequency rangeis designed using a wideband operational amplifier (OPAMP and squaring circuits. The wideband OPAMP is designed using 10 identical NMOS transistorsand operated with supply voltages of ±12V. Two NMOS transistors and two wideband OPAMP are utilized in the design of the proposed squaring circuit. All the NMOS transistors are based on 0.35µm NMOStechnology. The multiplier has input and output voltage ranges of ±10 V, high range of linearity from -10 V to +10 V, and cutoff frequency of about 5 GHz. The proposed multiplier is designed on PSpice in Orcad 16.6

Lagrange-multiplier tests for weak exogeneity: a synthesis.

NARCIS (Netherlands)

Boswijk, H.P.; Urbain, J.P.

1997-01-01

This paper unifies two seemingly separate approaches to test weak exogeneity in dynamic regression models with Lagrange-multiplier statistics. The first class of tests focuses on the orthogonality between innovations and conditioning variables, and thus is related to the Durbin-Wu-Hausman

Jacobi's last multiplier and symmetries for the Kepler problem plus a lineal story

International Nuclear Information System (INIS)

Nucci, M C; Leach, P G L

2004-01-01

We calculate the first integrals of the Kepler problem by the method of Jacobi's last multiplier using the symmetries for the equations of motion. Also we provide another example which shows that Jacobi's last multiplier together with Lie symmetries unveils many first integrals neither necessarily algebraic nor rational whereas other published methods may yield just one

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)

Safety analysis report for the Neutron Multiplier Facility, 329 Building

International Nuclear Information System (INIS)

Rieck, H.G.

1978-09-01

Neutron multiplication is a process wherein the flux of a neutron source such as 252 Cf is enhanced by fission reactions that occur in a subcritical assemblage of fissile material. The multiplication factor of the device depends upon the consequences of neutron reactions with matter and is independent of the initial number of neutrons present. Safe utilization of such a device demands that the fissile material assemblage be maintained in a subcritical state throughout all normal and credibly abnormal conditions. Examples of things that can alter the multiplication factor (and degree of subcriticality) are temperature fluctuations, changes in moderator material such as voiding or composition, addition of fissile materials, and change in assembly configuration. The Neutron Multiplier Facility (NMF) utilizes a multiplier- 252 Cf assembly to produce neutrons for activation analysis of organic and inorganic environmental samples and for on-line mass spectrometry analysis of fission products which diffuse from a stationary fissile target (less than or equal to 4 g fissile material) located in the Neutron Multiplier. The NMF annex to the 329 Building provides close proximity to related counting equipment, and delay between sample irradiation and counting is minimized

The Uncertainty Multiplier and Business Cycles

OpenAIRE

Saijo, Hikaru

2013-01-01

I study a business cycle model where agents learn about the state of the economy by accumulating capital. During recessions, agents invest less, and this generates noisier estimates of macroeconomic conditions and an increase in uncertainty. The endogenous increase in aggregate uncertainty further reduces economic activity, which in turn leads to more uncertainty, and so on. Thus, through changes in uncertainty, learning gives rise to a multiplier effect that amplifies business cycles. I use ...

A high reliability automatic multiplier for a mass spectrometer ion detector circuit

International Nuclear Information System (INIS)

Hoshino, Kiichi; Satooka, Sakae

1978-01-01

An automatic multiplier of an ion detector circuit for measurement of isotopic abundance ratio of heavy hydrogen to be used with a single collector has been constructed. This multiplier works at 1/1, 1/5, 1/20, 1/100, 1/500, 1/2000 and infinity, and the input voltage which is required to change the range from 1/1 to 1/5 is 10 mV and that from 1/2000 to infinity is 20 V. As the amplifier preceding the automatic multiplier, a vibrating reed electrometer which generates maximum output of 30 V is used. On measurement, marks which indicate the magnifications are recorded on the chart of electronic recorder. It is possible to set the minimum magnification at 1/1, 1/5, or 1/20 by a switch for setting the minimum magnification. (author)

Evaluation of multiplier effect of housing investments in the city economy

Science.gov (United States)

Ovsiannikova, T.; Rabtsevich, O.; Yugova, I.

2017-01-01

The given study presents evaluation of the role and significance of housing investments providing stable social and economic development of a city. It also justifies multiplier impact of investments in housing construction on all the sectors of urban economy. Growth of housing investments generates multiplier effect triggering the development of other different interrelated sectors. The paper suggests approach developed by the authors to evaluate the level of city development. It involves defining gross city product on the basis of integral criterion of gross value added of types of economic activities in the city economy. The algorithm of gross value added generation in urban economy is presented as a result of multiplier effect of housing investments. The evaluation of the mentioned effect was shown on the case of the city of Tomsk (Russia). The study has revealed that multiplier effect allows obtaining four rubles of added value out of one ruble of housing investments in the city economy. Methods used in the present study include the ones of the System of National Accounts, as well as methods of statistical and structural analysis. It has been proved that priority investment in housing construction is considered to be the key factor for stable social and economic development of the city. Developed approach is intended for justification of priority directions in municipal and regional investment policy. City and regional governing bodies and potential investors are the ones to apply the given approach.

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.

Fourier Series, the DFT and Shape Modelling

DEFF Research Database (Denmark)

Skoglund, Karl

2004-01-01

This report provides an introduction to Fourier series, the discrete Fourier transform, complex geometry and Fourier descriptors for shape analysis. The content is aimed at undergraduate and graduate students who wish to learn about Fourier analysis in general, as well as its application to shape...

Atomic collisions in fusion plasmas involving multiply charged ions

International Nuclear Information System (INIS)

Salzborn, E.

1980-01-01

A short survey is given on atomic collisions involving multiply charged ions. The basic features of charge transfer processes in ion-ion and ion-atom collisions relevant to fusion plasmas are discussed. (author)

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

Energy and intensity distributions of 0.279 MeV multiply Compton-scattered photons in soldering material

International Nuclear Information System (INIS)

Singh, Manpreet; Singh, Gurvinderjit; Singh, Bhajan; Sandhu, B.S.

2007-01-01

An inverse response matrix converts the observed pulse-height distribution of a NaI(Tl) scintillation detector to a photon spectrum. This also results in extraction of intensity distribution of multiply scattered events originating from interactions of 0.279 MeV photons with thick targets of soldering material. The observed pulse-height distributions are a composite of singly and multiply scattered events in addition to bremmstrahlung-and Rayleigh-scattered events. To evaluate the contribution of multiply scattered events, the spectrum of singly scattered events contributing to inelastic Compton peak is reconstructed analytically. The optimum thickness (saturation depth), at which the number of multiply scattered events saturates, has been measured. Monte Carlo calculations also support the present results

Proposal for electro-optic multiplier based on dual transverse electro-optic Kerr effect.

Science.gov (United States)

Li, Changsheng

2008-10-20

A novel electro-optic multiplier is proposed, which can perform voltage multiplication operation by use of the Kerr medium exhibiting dual transverse electro-optic Kerr effect. In this kind of Kerr medium, electro-optic phase retardation is proportional to the square of its applied electric field, and orientations of the field-induced birefringent axes are only related to the direction of the field. Based on this effect, we can design an electro-optic multiplier by selecting the crystals of 6/mmm, 432, and m3m classes and isotropic Kerr media such as glass. Simple calculation demonstrates that a kind of glass-ceramic material with a large Kerr constant can be used for the design of the proposed electro-optic multiplier.

Garbage-free reversible constant multipliers for arbitrary integers

DEFF Research Database (Denmark)

Mogensen, Torben Ægidius

2013-01-01

We present a method for constructing reversible circuitry for multiplying integers by arbitrary integer constants. The method is based on Mealy machines and gives circuits whose size are (in the worst case) linear in the size of the constant. This makes the method unsuitable for large constants...

Quadrature formulas for Fourier coefficients

KAUST Repository

Bojanov, Borislav

2009-09-01

We consider quadrature formulas of high degree of precision for the computation of the Fourier coefficients in expansions of functions with respect to a system of orthogonal polynomials. In particular, we show the uniqueness of a multiple node formula for the Fourier-Tchebycheff coefficients given by Micchelli and Sharma and construct new Gaussian formulas for the Fourier coefficients of a function, based on the values of the function and its derivatives. © 2009 Elsevier B.V. All rights reserved.

Image restorations constrained by a multiply exposed picture

International Nuclear Information System (INIS)

Breedlove, J.R. Jr.; Kruger, R.P.; Trussell, H.J.; Hunt, B.R.

1977-01-01

There are a number of possible industrial and scientific applications of nanosecond cineradiographs. While the technology exists to produce closely spaced pulses of x rays for this application, the quality of the time-resolved radiographs is severely limited. The limitations arise from the necessity of using a fluorescent screen to convert the transmitted x rays to light and then using electro-optical imaging systems to gate and to record the images with conventional high-speed cameras. It has been proposed that in addition to the time-resolved images, a conventional multiply-exposed radiograph be obtained. Simulations are used to demonstrate that the additional information supplied by the multiply-exposed radiograph can be used to improve the quality of digital image restorations of the time-resolved pictures over what could be achieved with the degraded images alone. Because of the need for image registration and rubber sheet transformations, this problem is one which can best be solved on a digital, as opposed to an optical, computer

Multiplier-free filters for wideband SAR

DEFF Research Database (Denmark)

Dall, Jørgen; Christensen, Erik Lintz

2001-01-01

This paper derives a set of parameters to be optimized when designing filters for digital demodulation and range prefiltering in SAR systems. Aiming at an implementation in field programmable gate arrays (FPGAs), an approach for the design of multiplier-free filters is outlined. Design results...... are presented in terms of filter complexity and performance. One filter has been coded in VHDL and preliminary results indicate that the filter can meet a 2 GHz input sample rate....

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.

Solution of second order linear fuzzy difference equation by Lagrange's multiplier method

Directory of Open Access Journals (Sweden)

Sankar Prasad Mondal

2016-06-01

Full Text Available In this paper we execute the solution procedure for second order linear fuzzy difference equation by Lagrange's multiplier method. In crisp sense the difference equation are easy to solve, but when we take in fuzzy sense it forms a system of difference equation which is not so easy to solve. By the help of Lagrange's multiplier we can solved it easily. The results are illustrated by two different numerical examples and followed by two applications.

Fourier Series Optimization Opportunity

Science.gov (United States)

Winkel, Brian

2008-01-01

This note discusses the introduction of Fourier series as an immediate application of optimization of a function of more than one variable. Specifically, it is shown how the study of Fourier series can be motivated to enrich a multivariable calculus class. This is done through discovery learning and use of technology wherein students build the…

Design of Low Power Multiplier with Energy Efficient Full Adder Using DPTAAL

Directory of Open Access Journals (Sweden)

A. Kishore Kumar

2013-01-01

Full Text Available Asynchronous adiabatic logic (AAL is a novel lowpower design technique which combines the energy saving benefits of asynchronous systems with adiabatic benefits. In this paper, energy efficient full adder using double pass transistor with asynchronous adiabatic logic (DPTAAL is used to design a low power multiplier. Asynchronous adiabatic circuits are very low power circuits to preserve energy for reuse, which reduces the amount of energy drawn directly from the power supply. In this work, an 8×8 multiplier using DPTAAL is designed and simulated, which exhibits low power and reliable logical operations. To improve the circuit performance at reduced voltage level, double pass transistor logic (DPL is introduced. The power results of the proposed multiplier design are compared with the conventional CMOS implementation. Simulation results show significant improvement in power for clock rates ranging from 100 MHz to 300 MHz.

DO PUBLIC AND PRIVATE DEBT LEVELS AFFECT THE SIZE OF FISCAL MULTIPLIERS?

Directory of Open Access Journals (Sweden)

Chairul Adi

2017-09-01

Full Text Available This paper investigates the effectiveness of fiscal policies – as measured by the impact and cumulative multipliers – and how they interact with public and private debt. Harnessing the moderated panel regression approach, based on the yearly data set of several economies during the period from 1996 to 2012, the analysis is focused on the impact of spending-and-revenue-based fiscal policies on economic growth and how these fiscal instruments interact with public and private indebtedness. The result of spending stimuli advocates the basic Keynesian theory. An increase in public expenditures contemporaneously generates a positive multiplier, of around 0.29 – 0.44 and around 0.45 – 0.58 during two years. Decomposing the expenditures into their elements, this paper documents a stronger impact from public investment than that from government purchases. On the other hand, the revenue stimuli seem to follow the Ricardian Equivalence Hypothesis (REH, arguing that current tax cuts are inconsequential. The impact and cumulative multipliers for this fiscal instrument have mixed results, ranging from -0.21 to 0.05 and -0.26 to 0.06, respectively. Moreover, no robust evidence is found to support the argument that government debt moderates the effectiveness of fiscal policies. The size of the multipliers for both spending and revenue policies remain constant with the level of public debt. On the other hand, private debt appears to show a statistically significant moderating effect on spending stimuli. Its impact on spending multipliers, however, is economically insignificant. The moderation effect of private debt on the revenue stimuli does not seem to exist. Finally, this paper documents that both public and private debt exhibit a negative and statistically significant estimation for economic output.

Classical Fourier analysis

CERN Document Server

Grafakos, Loukas

2014-01-01

The main goal of this text is to present the theoretical foundation of the field of Fourier analysis on Euclidean spaces. It covers classical topics such as interpolation, Fourier series, the Fourier transform, maximal functions, singular integrals, and Littlewood–Paley theory. The primary readership is intended to be graduate students in mathematics with the prerequisite including satisfactory completion of courses in real and complex variables. The coverage of topics and exposition style are designed to leave no gaps in understanding and stimulate further study. This third edition includes new Sections 3.5, 4.4, 4.5 as well as a new chapter on “Weighted Inequalities,” which has been moved from GTM 250, 2nd Edition. Appendices I and B.9 are also new to this edition.  Countless corrections and improvements have been made to the material from the second edition. Additions and improvements include: more examples and applications, new and more relevant hints for the existing exercises, new exercises, and...

The Gas Electron Multiplier Chamber Exhibition LEPFest 2000

CERN Multimedia

2000-01-01

The Gas Electron Multiplier (GEM) is a novel device introduced in 1996.Large area detectors based on this technology are in construction for high energy physics detectors.This technology can also be used for high-rate X-ray imaging in medical diagnostics and for monitoring irradiation during cancer treatment

Auditing the multiply-related concepts within the UMLS.

Science.gov (United States)

Mougin, Fleur; Grabar, Natalia

2014-10-01

This work focuses on multiply-related Unified Medical Language System (UMLS) concepts, that is, concepts associated through multiple relations. The relations involved in such situations are audited to determine whether they are provided by source vocabularies or result from the integration of these vocabularies within the UMLS. We study the compatibility of the multiple relations which associate the concepts under investigation and try to explain the reason why they co-occur. Towards this end, we analyze the relations both at the concept and term levels. In addition, we randomly select 288 concepts associated through contradictory relations and manually analyze them. At the UMLS scale, only 0.7% of combinations of relations are contradictory, while homogeneous combinations are observed in one-third of situations. At the scale of source vocabularies, one-third do not contain more than one relation between the concepts under investigation. Among the remaining source vocabularies, seven of them mainly present multiple non-homogeneous relations between terms. Analysis at the term level also shows that only in a quarter of cases are the source vocabularies responsible for the presence of multiply-related concepts in the UMLS. These results are available at: http://www.isped.u-bordeaux2.fr/ArticleJAMIA/results_multiply_related_concepts.aspx. Manual analysis was useful to explain the conceptualization difference in relations between terms across source vocabularies. The exploitation of source relations was helpful for understanding why some source vocabularies describe multiple relations between a given pair of terms. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Quantum mechanics in a multiply connected region

International Nuclear Information System (INIS)

Miyazawa, H.

1986-01-01

It is usually assumed that wave fields or wave functions are single valued functions of space-time. However, the phase of a complex field is an unobservable quantity and there is no obvious reason that it must be single valued. On this point quantum mechanics in a multiply connected regions is not well formulated. This ambiguity appears e.g., in the case of the Bohm-Aharonov effect concerning the observability of the vector potential around a magnetic flux. The author discusses the single or multiple valuedness of wave functions and attempts to see if such an effect really exists or not. The wave function of a charged particle in a multiply connected region is not necessarily single valued. The condition that the ground state energy be a minimum fixes the character of the multiple valuedness. For a charged particle around a magnetic flux a multiple valued wave function is preferable and no Bohm-Aharonov effect is observed. The minimum energy principle is proved if one also considers the interaction of a charged particle with external objects. Then theoretically the Bohm-Aharonov effect should not be observed. Experiments are not yet conclusive on this point

In-situ monitoring of blood glucose level for dialysis machine by AAA-battery-size ATR Fourier spectroscopy

Science.gov (United States)

Hosono, Satsuki; Sato, Shun; Ishida, Akane; Suzuki, Yo; Inohara, Daichi; Nogo, Kosuke; Abeygunawardhana, Pradeep K.; Suzuki, Satoru; Nishiyama, Akira; Wada, Kenji; Ishimaru, Ichiro

2015-07-01

For blood glucose level measurement of dialysis machines, we proposed AAA-battery-size ATR (Attenuated total reflection) Fourier spectroscopy in middle infrared light region. The proposed one-shot Fourier spectroscopic imaging is a near-common path and spatial phase-shift interferometer with high time resolution. Because numerous number of spectral data that is 60 (= camera frame rare e.g. 60[Hz]) multiplied by pixel number could be obtained in 1[sec.], statistical-averaging improvement realize high-accurate spectral measurement. We evaluated the quantitative accuracy of our proposed method for measuring glucose concentration in near-infrared light region with liquid cells. We confirmed that absorbance at 1600[nm] had high correlations with glucose concentrations (correlation coefficient: 0.92). But to measure whole-blood, complex light phenomenon caused from red blood cells, that is scattering and multiple reflection or so, deteriorate spectral data. Thus, we also proposed the ultrasound-assisted spectroscopic imaging that traps particles at standing-wave node. Thus, if ATR prism is oscillated mechanically, anti-node area is generated around evanescent light field on prism surface. By elimination complex light phenomenon of red blood cells, glucose concentration in whole-blood will be quantify with high accuracy. In this report, we successfully trapped red blood cells in normal saline solution with ultrasonic standing wave (frequency: 2[MHz]).

Charge amplification and transfer processes in the gas electron multiplier

International Nuclear Information System (INIS)

Bachmann, S.; Bressan, A.; Ropelewski, L.; Sauli, F.; Sharma, A.; Moermann, D.

1999-01-01

We report the results of systematic investigations on the operating properties of detectors based on the gas electron multiplier (GEM). The dependence of gain and charge collection efficiency on the external fields has been studied in a range of values for the hole diameter and pitch. The collection efficiency of ionization electrons into the multiplier, after an initial increase, reaches a plateau extending to higher values of drift field the larger the GEM voltage and its optical transparency. The effective gain, fraction of electrons collected by an electrode following the multiplier, increases almost linearly with the collection field, until entering a steeper parallel plate multiplication regime. The maximum effective gain attainable increases with the reduction in the hole diameter, stabilizing to a constant value at a diameter approximately corresponding to the foil thickness. Charge transfer properties appear to depend only on ratios of fields outside and within the channels, with no interaction between the external fields. With proper design, GEM detectors can be optimized to satisfy a wide range of experimental requirements: tracking of minimum ionizing particles, good electron collection with small distortions in high magnetic fields, improved multi-track resolution and strong ion feedback suppression in large volume and time-projection chambers

Electron cyclotron resonance multiply charged ion sources

International Nuclear Information System (INIS)

Geller, R.

1975-01-01

Three ion sources, that deliver multiply charged ion beams are described. All of them are E.C.R. ion sources and are characterized by the fact that the electrons are emitted by the plasma itself and are accelerated to the adequate energy through electron cyclotron resonance (E.C.R.). They can work without interruption during several months in a quasi-continuous regime. (Duty cycle: [fr

Design, implementation and performance comparison of multiplier topologies in power-delay space

Directory of Open Access Journals (Sweden)

Mansi Jhamb

2016-03-01

Full Text Available With the advancements in the semiconductor industry, designing a high performance processor is a prime concern. Multiplier is one of the most crucial parts in almost every digital signal processing applications. This paper addresses the implementation of an 8-bit multiplier design employing CMOS full adder, full adder using Double Pass Transistor (DPL and multioutput carry Lookahead logic (CLA. DPL adder avoids the noise margin problem and speed degradation at low value of supply voltages associated with complementary pass transistor (CPL logic circuits. Multioutput carry lookahead adder leads to significant improvement in the speed of the overall circuitry. The investigation is carried out with simulation runs on HSPICE environment using 90 nm process technology at 25 °C. Finally, the design guidelines are derived to select the most suitable topology for the desired applications. Investigation reveals that multiplier design using multioutput carry lookahead adder proves to be more speed efficient in comparison with the other two considered design strategies.

Formation of molecules in interstellar clouds from singly and multiply ionized atoms

International Nuclear Information System (INIS)

Langer, W.D.; and NASA, Institute for Space Studies, Goddard Space Flight Center, New York)

1978-01-01

Soft X-ray and cosmic rays produce multiply ionized atoms which may initiate molecule production in interstellar clouds. This molecule production can occur via ion-molecule reactions with H 2 , either directly from the multiply ionized atom (e.g.,C ++ + H 2 →CH + + H + ), or indirectly from the singly ionized atoms (e.g., N + + H 2 →NH + + H) that are formed from the recombination or charge transfer of the highly ionized atom (e.g., N ++ + e→N + + hv). We investigate the contribution of these reactions to the abundances of carbon-, nitrogen-, and oxygen-bearing molecules in isobaric models of diffuse clouds. In the presence of the average flux estimated for the diffuse soft X-ray background, multiply ionized atoms contribute only minimally (a few percent) to carbon-bearing molecules such as CH. In the neighborhood of diffuse structures or discrete sources, however, where the X-ray flux is enhanced, multiple ionization is considerably more important for molecule production

Lower-Order Compensation Chain Threshold-Reduction Technique for Multi-Stage Voltage Multipliers.

Science.gov (United States)

Dell' Anna, Francesco; Dong, Tao; Li, Ping; Wen, Yumei; Azadmehr, Mehdi; Casu, Mario; Berg, Yngvar

2018-04-17

This paper presents a novel threshold-compensation technique for multi-stage voltage multipliers employed in low power applications such as passive and autonomous wireless sensing nodes (WSNs) powered by energy harvesters. The proposed threshold-reduction technique enables a topological design methodology which, through an optimum control of the trade-off among transistor conductivity and leakage losses, is aimed at maximizing the voltage conversion efficiency (VCE) for a given ac input signal and physical chip area occupation. The conducted simulations positively assert the validity of the proposed design methodology, emphasizing the exploitable design space yielded by the transistor connection scheme in the voltage multiplier chain. An experimental validation and comparison of threshold-compensation techniques was performed, adopting 2N5247 N-channel junction field effect transistors (JFETs) for the realization of the voltage multiplier prototypes. The attained measurements clearly support the effectiveness of the proposed threshold-reduction approach, which can significantly reduce the chip area occupation for a given target output performance and ac input signal.

Teaching Fourier optics through ray matrices

International Nuclear Information System (INIS)

Moreno, I; Sanchez-Lopez, M M; Ferreira, C; Davis, J A; Mateos, F

2005-01-01

In this work we examine the use of ray-transfer matrices for teaching and for deriving some topics in a Fourier optics course, exploiting the mathematical simplicity of ray matrices compared to diffraction integrals. A simple analysis of the physical meaning of the elements of the ray matrix provides a fast derivation of the conditions to obtain the optical Fourier transform. We extend this derivation to fractional Fourier transform optical systems, and derive the order of the transform from the ray matrix. Some examples are provided to stress this point of view, both with classical and with graded index lenses. This formulation cannot replace the complete explanation of Fourier optics provided by the wave theory, but it is a complementary tool useful to simplify many aspects of Fourier optics and to relate them to geometrical optics

X-ray interferometric Fourier holography

International Nuclear Information System (INIS)

Balyan, M.K.

2016-01-01

The X-ray interferometric Fourier holography is proposed and theoretically investigated. Fourier The X-ray interferometric Young fringes and object image reconstruction are investigated. It is shown that the interference pattern of two slits formed on the exit surface of the crystal-analyzer (the third plate of the interferometer) is the X-ray interferometric Young fringes. An expression for X-ray interferometric Young fringes period is obtained. The subsequent reconstruction of the slit image as an object is performed by means of Fourier transform of the intensity distribution on the hologram. Three methods of reconstruction of the amplitude transmission complex function of the object are presented: analytical - approximate method, method of iteration and step by step method. As an example the X-ray Fourier interferometric hologram recording and the complex amplitude transmission function reconstruction for a beryllium circular wire are considered

Composite Field Multiplier based on Look-Up Table for Elliptic Curve Cryptography Implementation

Directory of Open Access Journals (Sweden)

Marisa W. Paryasto

2012-04-01

Full Text Available Implementing a secure cryptosystem requires operations involving hundreds of bits. One of the most recommended algorithm is Elliptic Curve Cryptography (ECC. The complexity of elliptic curve algorithms and parameters with hundreds of bits requires specific design and implementation strategy. The design architecture must be customized according to security requirement, available resources and parameter choices. In this work we propose the use of composite field to implement finite field multiplication for ECC implementation. We use 299-bit keylength represented in GF((21323 instead of in GF(2299. Composite field multiplier can be implemented using different multiplier for ground-field and for extension field. In this paper, LUT is used for multiplication in the ground-field and classic multiplieris used for the extension field multiplication. A generic architecture for the multiplier is presented. Implementation is done with VHDL with the target device Altera DE2. The work in this paper uses the simplest algorithm to confirm the idea that by dividing field into composite, use different multiplier for base and extension field would give better trade-off for time and area. This work will be the beginning of our more advanced further research that implements composite-field using Mastrovito Hybrid, KOA and LUT.

Testing of money multiplier model for Pakistan: does monetary base carry any information?

Directory of Open Access Journals (Sweden)

Muhammad Arshad Khan

2010-02-01

Full Text Available This paper tests the constancy and stationarity of mechanic version of the money multiplier model for Pakistan using monthly data over the period 1972M1-2009M2. We split the data into pre-liberalization (1972M1-1990M12 and post-liberalization (1991M1-2009M2 periods to examine the impact of financial sector reforms. We first examine the constancy and stationarity of the money multiplier and the results suggest the money multiplier remains non-stationary for the entire sample period and sub-periods. We then tested cointegration between money supply and monetary base and find the evidence of cointegration between two variables for the entire period and two sub-periods. The coefficient restrictions are satisfied only for the post-liberalization period. Two-way long-run causality between money supply and monetary base is found for the entire period and post-liberalization. For the post-liberalization period the evidence of short-run causality running from monetary base to money supply is also identified. On the whole, the results suggest that money multiplier model can serve as framework for conducting short-run monetary policy in Pakistan. However, the monetary authority may consider the co-movements between money supply and reserve money at the time of conducting monetary policy.

Composite Field Multiplier based on Look-Up Table for Elliptic Curve Cryptography Implementation

Directory of Open Access Journals (Sweden)

Marisa W. Paryasto

2013-09-01

Full Text Available Implementing a secure cryptosystem requires operations involving hundreds of bits. One of the most recommended algorithm is Elliptic Curve Cryptography (ECC. The complexity of elliptic curve algorithms and parameters with hundreds of bits requires specific design and implementation strategy. The design architecture must be customized according to security requirement, available resources and parameter choices. In this work we propose the use of composite field to implement finite field multiplication for ECC implementation. We use 299-bit keylength represented in GF((21323 instead of in GF(2299. Composite field multiplier can be implemented using different multiplier for ground-field and for extension field. In this paper, LUT is used for multiplication in the ground-field and classic multiplieris used for the extension field multiplication. A generic architecture for the multiplier is presented. Implementation is done with VHDL with the target device Altera DE2. The work in this paper uses the simplest algorithm to confirm the idea that by dividing field into composite, use different multiplier for base and extension field would give better trade-off for time and area. This work will be the beginning of our more advanced further research that implements composite-field using Mastrovito Hybrid, KOA and LUT.

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

Fourier analysis and stochastic processes

CERN Document Server

Brémaud, Pierre

2014-01-01

This work is unique as it provides a uniform treatment of the Fourier theories of functions (Fourier transforms and series, z-transforms), finite measures (characteristic functions, convergence in distribution), and stochastic processes (including arma series and point processes). It emphasises the links between these three themes. The chapter on the Fourier theory of point processes and signals structured by point processes is a novel addition to the literature on Fourier analysis of stochastic processes. It also connects the theory with recent lines of research such as biological spike signals and ultrawide-band communications. Although the treatment is mathematically rigorous, the convivial style makes the book accessible to a large audience. In particular, it will be interesting to anyone working in electrical engineering and communications, biology (point process signals) and econometrics (arma models). A careful review of the prerequisites (integration and probability theory in the appendix, Hilbert spa...

A simple approach to Fourier aliasing

International Nuclear Information System (INIS)

Foadi, James

2007-01-01

In the context of discrete Fourier transforms the idea of aliasing as due to approximation errors in the integral defining Fourier coefficients is introduced and explained. This has the positive pedagogical effect of getting to the heart of sampling and the discrete Fourier transform without having to delve into effective, but otherwise long and structured, introductions to the topic, commonly met in advanced, specialized books

Smooth bifurcation for variational inequalities based on Lagrange multipliers

Czech Academy of Sciences Publication Activity Database

Eisner, Jan; Kučera, Milan; Recke, L.

2006-01-01

Roč. 19, č. 9 (2006), s. 981-1000 ISSN 0893-4983 R&D Projects: GA AV ČR(CZ) IAA100190506 Institutional research plan: CEZ:AV0Z10190503 Keywords : abstract variational inequality * bifurcation * Lagrange multipliers Subject RIV: BA - General Mathematics

Instructional Computing Project Uses "Multiplier Effect" to Train Florida Teachers.

Science.gov (United States)

Roblyer, M. D.; Castine, W. H.

1987-01-01

Reviews the efforts undertaken in the Florida Model Microcomputer Trainer Project (FMMTP) and its statewide impact. Outlines its procedural strategies, trainer curriculum, networking system, and the results of its multiplier effect. (ML)

Rhinoplasty for the multiply revised nose.

Science.gov (United States)

Foda, Hossam M T

2005-01-01

To evaluate the problems encountered on revising a multiply operated nose and the methods used in correcting such problems. The study included 50 cases presenting for revision rhinoplasty after having had 2 or more previous rhinoplasties. An external rhinoplasty approach was used in all cases. Simultaneous septal surgery was done whenever indicated. All cases were followed for a mean period of 32 months (range, 1.5-8 years). Evaluation of the surgical result depended on clinical examination, comparison of pre- and postoperative photographs, and degree of patients' satisfaction with their aesthetic and functional outcome. Functionally, 68% suffered nasal obstruction that was mainly caused by septal deviations and nasal valve problems. Aesthetically, the most common deformities of the upper two thirds of the nose included pollybeak (64%), dorsal irregularities (54%), dorsal saddle (44%), and open roof deformity (42%), whereas the deformities of lower third included depressed tip (68%), tip contour irregularities (60%), and overrotated tip (42%). Nasal grafting was necessary in all cases; usually more than 1 type of graft was used in each case. Postoperatively, 79% of the patients, with preoperative nasal obstruction, reported improved breathing; 84% were satisfied with their aesthetic result; and only 8 cases (16%) requested further revision to correct minor deformities. Revision of a multiply operated nose is a complex and technically demanding task, yet, in a good percentage of cases, aesthetic as well as functional improvement are still possible.

Fission multipliers for D-D/D-T neutron generators

International Nuclear Information System (INIS)

Lou, T.P.; Vujic, J.L.; Koivunoro, H.; Reijonen, J.; Leung, K.-N.

2003-01-01

A compact D-D/D-T fusion based neutron generator is being designed at the Lawrence Berkeley National Laboratory to have a potential yield of 10 12 D-D n/s and 10 14 D-T n/s. Because of its high neutron yield and compact size (∼20 cm in diameter by 4 cm long), this neutron generator design will be suitable for many applications. However, some applications required higher flux available from nuclear reactors and spallation neutron sources operated with GeV proton beams. In this study, a subcritical fission multiplier with k eff of 0.98 is coupled with the compact neutron generators in order to increase the neutron flux output. We have chosen two applications to show the gain in flux due to the use of fission multipliers--in-core irradiation and out-of-core irradiation. For the in-core irradiation, we have shown that a gain of ∼25 can be achieved in a positron production system using D-T generator. For the out-of-core irradiation, a gain of ∼17 times is obtained in Boron Neutron Capture Therapy (BNCT) using a D-D neutron generator. The total number of fission neutrons generated by a source neutron in a fission multiplier with k eff is ∼50. For the out-of-core irradiation, the theoretical maximum net multiplication is ∼30 due to the absorption of neutrons in the fuel. A discussion of the achievable multiplication and the theoretical multiplication will be presented in this paper

Different I/O Standard and Technology Based Thermal Aware Energy Efficient Vedic Multiplier Design for Green Wireless Communication on FPGA

DEFF Research Database (Denmark)

Goswami, Kavita; Pandey, Bishwajeet; Kumar, Tanesh

2017-01-01

and that eventually decrease power dissipation of wireless communications systems. In order to study the effect of different process technology (40, 65, 90 nm) on our design, a novel design is implemented on 40, 65 and 90 nm based FPGA. In this work, we are integrating thermal aware design approach for energy......This paper deals with low power multiplier design that plays a significant role in green wireless communications systems. Over the period of time, researchers have proposed various multiplier designs in order to get high speed. Vedic multiplier is considered as one of the low power multiplier along...... with high speed as compared with traditional array and booth multipliers. Vedic Multiplier contains a total of sixteen algorithms/sutras for predominantly logical operations. This research focuses on thermal aspects and energy efficiency of wireless communications systems with the thermal aware low power...

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.

The derivative-free Fourier shell identity for photoacoustics.

Science.gov (United States)

Baddour, Natalie

2016-01-01

In X-ray tomography, the Fourier slice theorem provides a relationship between the Fourier components of the object being imaged and the measured projection data. The Fourier slice theorem is the basis for X-ray Fourier-based tomographic inversion techniques. A similar relationship, referred to as the 'Fourier shell identity' has been previously derived for photoacoustic applications. However, this identity relates the pressure wavefield data function and its normal derivative measured on an arbitrary enclosing aperture to the three-dimensional Fourier transform of the enclosed object evaluated on a sphere. Since the normal derivative of pressure is not normally measured, the applicability of the formulation is limited in this form. In this paper, alternative derivations of the Fourier shell identity in 1D, 2D polar and 3D spherical polar coordinates are presented. The presented formulations do not require the normal derivative of pressure, thereby lending the formulas directly adaptable for Fourier based absorber reconstructions.

Utilization of a channel electron multiplier for counting-measurement on condensed molecular jet

International Nuclear Information System (INIS)

Le Bihan, A.M.; Bottiglioni, F.; Coutant, J.; Fois, M.; CEA Centre d'Etudes Nucleaires de Fontenay-aux-Roses, 92

1974-01-01

A channel electron multiplier has been used for counting ionized clusters containing up to a few thousands molecules; clusters are accelerated towards a negative (approximately-220V) copper target; a larger negative bias (approximately-3000V) is applied to the multiplier entrance so as to collect positive secondary ions and/or reflected cluster fragments; in the present application this gives better signal to noise ratio than detecting clusters directly or by secondary electron emission on the target [fr

Radiation-hardened I2L 8*8 multiplier circuit

International Nuclear Information System (INIS)

Doyle, B.R.; Kreps, S.A.; Van Vonno, N.W.; Lake, G.W.

1979-01-01

Development of improved Substrate Fed I 2 L (SFL) processing has been combined with geometry and fanout constraints to design a radiation hardened LSI 8.8 Multiplier. This study describes details of the process and circuit design and gives resultant electrical and radiation test performance

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

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.

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.

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.

Lower-Order Compensation Chain Threshold-Reduction Technique for Multi-Stage Voltage Multipliers

Directory of Open Access Journals (Sweden)

Francesco Dell’ Anna

2018-04-01

Full Text Available This paper presents a novel threshold-compensation technique for multi-stage voltage multipliers employed in low power applications such as passive and autonomous wireless sensing nodes (WSNs powered by energy harvesters. The proposed threshold-reduction technique enables a topological design methodology which, through an optimum control of the trade-off among transistor conductivity and leakage losses, is aimed at maximizing the voltage conversion efficiency (VCE for a given ac input signal and physical chip area occupation. The conducted simulations positively assert the validity of the proposed design methodology, emphasizing the exploitable design space yielded by the transistor connection scheme in the voltage multiplier chain. An experimental validation and comparison of threshold-compensation techniques was performed, adopting 2N5247 N-channel junction field effect transistors (JFETs for the realization of the voltage multiplier prototypes. The attained measurements clearly support the effectiveness of the proposed threshold-reduction approach, which can significantly reduce the chip area occupation for a given target output performance and ac input signal.

Mining, regional Australia and the economic multiplier

Directory of Open Access Journals (Sweden)

Paul Cleary

2012-12-01

Full Text Available Mining in Australia has traditionally delivered a strong development multiplier for regional communities where most mines are based. This relationship has weakened in recent decades as a result of the introduction of mobile workforces - typically known as fly in, fly out. Political parties have responded with policies known as ‘royalties for regions’, though in designing them they overlooked long established Indigenous arrangements for sharing benefits with areas affected directly by mining.

Generalized fiber Fourier optics.

Science.gov (United States)

Cincotti, Gabriella

2011-06-15

A twofold generalization of the optical schemes that perform the discrete Fourier transform (DFT) is given: new passive planar architectures are presented where the 2 × 2 3 dB couplers are replaced by M × M hybrids, reducing the number of required connections and phase shifters. Furthermore, the planar implementation of the discrete fractional Fourier transform (DFrFT) is also described, with a waveguide grating router (WGR) configuration and a properly modified slab coupler.

Handbook of Fourier analysis & its applications

CERN Document Server

Marks, Robert J

2009-01-01

Fourier analysis has many scientific applications - in physics, number theory, combinatorics, signal processing, probability theory, statistics, option pricing, cryptography, acoustics, oceanography, optics and diffraction, geometry, and other areas. In signal processing and related fields, Fourier analysis is typically thought of as decomposing a signal into its component frequencies and their amplitudes. This practical, applications-based professional handbook comprehensively covers the theory and applications of Fourier Analysis, spanning topics from engineering mathematics, signal process

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...

Photoionization of multiply charged ions at the advanced light source

International Nuclear Information System (INIS)

Schlachter, A.S.; Kilcoyne, A.L.D.; Aguilar, A.; Gharaibeh, M.F.; Emmons, E.D.; Scully, S.W.J.; Phaneuf, R.A.; Muller, A.; Schippers, S.; Alvarez, I.; Cisneros, C.; Hinojosa, G.; McLaughlin, B.M.

2004-01-01

Photoionization of multiply charged ions is studied using the merged-beams technique at the Advanced Light Source. Absolute photoionization cross sections have been measured for a variety of ions along both isoelectronic and isonuclear sequences

Exponential decay and exponential recovery of modal gains in high count rate channel electron multipliers

International Nuclear Information System (INIS)

Hahn, S.F.; Burch, J.L.

1980-01-01

A series of data on high count rate channel electron multipliers revealed an initial drop and subsequent recovery of gains in exponential fashion. The FWHM of the pulse height distribution at the initial stage of testing can be used as a good criterion for the selection of operating bias voltage of the channel electron multiplier

ANALYSIS OF THE INVESTMENT ARBITRAGE STRATEGY USING FINANCIAL MULTIPLIERS

Directory of Open Access Journals (Sweden)

Dmitry S. Pashkov

2013-01-01

Full Text Available This article describes an algorithm for stock pairs trading using financial multipliers of underlying companies. This algorithm has been tested on historical data and compared with classical Bollinger bands strategy. The results of tests were presented for two financial sectors of US stock market.

Generation of fast multiply charged ions in conical targets

International Nuclear Information System (INIS)

Demchenko, V.V.; Chukbar, K.V.

1990-01-01

So-called conical targets, when the thermonuclear fuel is compressed and heated in a conical cavity in a heavy material (lead, gold, etc.) with the help of a spherical segment that is accelerated by a laser pulse or a beam of charged particles, are often employed in experimental studies of inertial-confinement fusion. In spite of the obvious advantages of such a scheme, one of which is a significant reduction of the required energy input compared with the complete spherical target, it also introduces additional effects into the process of cumulation of energy. In this paper the authors call attention to an effect observed in numerical calculations: the hydrodynamic heating of a small group of multiply charged heavy ions of the walls of the conical cavity up to high energies (T i approx-gt 100 keV). This effect ultimately occurs as a result of the high radiation losses of a multiply charged plasma

Beyond the static money multiplier: in search of a dynamic theory of money

OpenAIRE

Berardi, Michele

2007-01-01

In this paper, we analyze the process of money creation in a credit economy. We start from the consideration that the traditional money multiplier is a poor description of this process and present an alternative and dynamic approach that takes into account the heterogeneity of agents in the economy and their interactions. We show that this heterogeneity can account for the instability of the multiplier and that it can make the system path-dependent. By using concepts and techniques borrowed f...

Fourier Series

Indian Academy of Sciences (India)

The theory of Fourier series deals with periodic functions. By a periodic ..... including Dirichlet, Riemann and Cantor occupied themselves with the problem of ... to converge only on a set which is negligible in a certain sense (Le. of measure ...

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

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

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.

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.

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....

Evaporator line for special electron tubes, in particular electron multipliers

International Nuclear Information System (INIS)

Richter, M.

1984-01-01

The invention has been aimed at reducing the effort for preventing short circuits in achieving certain material-dependent effects e.g. secondary emission, by deposition through evaporation in the production of electron tubes, in particular electron multipliers

A database analysis of information on multiply charged ions

International Nuclear Information System (INIS)

Delcroix, J.L.

1989-01-01

A statistical analysis of data related to multiply charged ions, is performed in GAPHYOR data base: over-all statistics by ionization degree from q=1 to q=99, 'historical' development from 1975 to 1987, distribution (for q≥ 5) over physical processes (energy levels, charge exchange,...) and chemical elements

Familiar Sports and Activities Adapted for Multiply Impaired Persons.

Science.gov (United States)

Schilling, Mary Lou, Ed.

1984-01-01

Means of adapting some familiar and popular physical activities for multiply impaired persons are described. Games reviewed are dice baseball, one base baseball, in-house bowling, wheelchair bowling, ramp bowling, swing-ball bowling, table tennis, shuffleboard, beanbag bingo and tic-tac-toe, balloon basketball, circle football, and wheelchair…

Mapped Fourier Methods for stiff problems in toroidal geometry

OpenAIRE

Guillard , Herve

2014-01-01

Fourier spectral or pseudo-spectral methods are usually extremely efficient for periodic problems. However this efficiency is lost if the solutions have zones of rapid variations or internal layers. For these cases, a large number of Fourier modes are required and this makes the Fourier method unpractical in many cases. This work investigates the use of mapped Fourier method as a way to circumvent this problem. Mapped Fourier method uses instead of the usual Fourier interpolant the compositio...

Multiply-negatively charged aluminium clusters and fullerenes

Energy Technology Data Exchange (ETDEWEB)

Walsh, Noelle

2008-07-15

Multiply negatively charged aluminium clusters and fullerenes were generated in a Penning trap using the 'electron-bath' technique. Aluminium monoanions were generated using a laser vaporisation source. After this, two-, three- and four-times negatively charged aluminium clusters were generated for the first time. This research marks the first observation of tetra-anionic metal clusters in the gas phase. Additionally, doubly-negatively charged fullerenes were generated. The smallest fullerene dianion observed contained 70 atoms. (orig.)

Tax Multipliers: Pitfalls in Measurement and Identification

OpenAIRE

Daniel Riera-Crichton; Carlos A. Vegh; Guillermo Vuletin

2012-01-01

We contribute to the literature on tax multipliers by analyzing the pitfalls in identification and measurement of tax shocks. Our main focus is on disentangling the discussion regarding the identification of exogenous tax policy shocks (i.e., changes in tax policy that are not the result of policymakers responding to output fluctuations) from the discussion related to the measurement of tax policy (i.e., finding a tax policy variable under the direct control of the policymaker). For this purp...

New Lagrange Multipliers for the Blind Adaptive Deconvolution Problem Applicable for the Noisy Case

Directory of Open Access Journals (Sweden)

Monika Pinchas

2016-02-01

Full Text Available Recently, a new blind adaptive deconvolution algorithm was proposed based on a new closed-form approximated expression for the conditional expectation (the expectation of the source input given the equalized or deconvolutional output where the output and input probability density function (pdf of the deconvolutional process were approximated with the maximum entropy density approximation technique. The Lagrange multipliers for the output pdf were set to those used for the input pdf. Although this new blind adaptive deconvolution method has been shown to have improved equalization performance compared to the maximum entropy blind adaptive deconvolution algorithm recently proposed by the same author, it is not applicable for the very noisy case. In this paper, we derive new Lagrange multipliers for the output and input pdfs, where the Lagrange multipliers related to the output pdf are a function of the channel noise power. Simulation results indicate that the newly obtained blind adaptive deconvolution algorithm using these new Lagrange multipliers is robust to signal-to-noise ratios (SNR, unlike the previously proposed method, and is applicable for the whole range of SNR down to 7 dB. In addition, we also obtain new closed-form approximated expressions for the conditional expectation and mean square error (MSE.

Features of produced flows of multiply charged ions at interaction of laser radiation with single-component solids

International Nuclear Information System (INIS)

Bedilov, M.R.; Bedilov, R.M.; Beysembaeva, H.B.; Sabitov, M.S.; Kamalova, J.O.

2006-01-01

Full text: The results of study features of formation multiply charged ions spectra of single-component solids depending on a target element composition in an interval of laser radiation power density q = 10 7 / 10 12 W/cm 2 with using of the laser multiply charged mass spectrometer [1] are given in this work. As single-component targets are used Be, B, C, Al, Ti, Fe, Co, Ni, Cu, Ag, Ta, W, Pt, Au as tablets in diameter of 10 mm and thickness of 3-5 mm. Analysis of the obtained mass-charge and energy spectra of multiply charged ions depending on a target element composition has allowed us to find features of formation spectra and escape multiply charged ions of a single-component targets. These features consist in characteristic changes: a threshold produced of ions; formation of mass-charge and energy spectra of multiply charged ions; nonlinear dependence of maximal charge number (Z max ) of ions from power density (q) of the laser; etc. Experimentally it was found that, with target atomic weight increase, threshold power of ions occurrence, nonlinearity ionization target structure, and intensity of ions, and energy spectra of ions increase. Let's note that, in case of targets Be, B, C, Al by laser radiation it is completely ionized and multiply charged ions and nuclei Be 4+ , B 5+ , C 6+ , Al 13+ are formed. The major level of ionization is attained in case of targets from Ti (Ti 17+ ) and Co (Co 18+ ). It is peculiar that structure formation and escape of multiply charged ion flows with Z max and nuclei depending on target element composition corresponds to various maximal values q of the laser. Increase of the maximal charge number of ions (atoms) observed with increase q of the laser for all investigated targets has nonlinear dependence in various levels that is especially shown beginning from q≥ 10 11 W/cm 2 . It is found that depending on target element composition multiply charged ions have a wide energy range with a maximum of allocation. With increase

Spectral multipliers on spaces of distributions associated with non-negative self-adjoint operators

DEFF Research Database (Denmark)

Georgiadis, Athanasios; Nielsen, Morten

2018-01-01

and Triebel–Lizorkin spaces with full range of indices is established too. As an application, we obtain equivalent norm characterizations for the spaces mentioned above. Non-classical spaces as well as Lebesgue, Hardy, (generalized) Sobolev and Lipschitz spaces are also covered by our approach.......We consider spaces of homogeneous type associated with a non-negative self-adjoint operator whose heat kernel satisfies certain upper Gaussian bounds. Spectral multipliers are introduced and studied on distributions associated with this operator. The boundedness of spectral multipliers on Besov...

Identification of multiply charged proteins and amino acid clusters by liquid nitrogen assisted spray ionization mass spectrometry.

Science.gov (United States)

Kumar Kailasa, Suresh; Hasan, Nazim; Wu, Hui-Fen

2012-08-15

The development of liquid nitrogen assisted spray ionization mass spectrometry (LNASI MS) for the analysis of multiply charged proteins (insulin, ubiquitin, cytochrome c, α-lactalbumin, myoglobin and BSA), peptides (glutathione, HW6, angiotensin-II and valinomycin) and amino acid (arginine) clusters is described. The charged droplets are formed by liquid nitrogen assisted sample spray through a stainless steel nebulizer and transported into mass analyzer for the identification of multiply charged protein ions. The effects of acids and modifier volumes for the efficient ionization of the above analytes in LNASI MS were carefully investigated. Multiply charged proteins and amino acid clusters were effectively identified by LNASI MS. The present approach can effectively detect the multiply charged states of cytochrome c at 400 nM. A comparison between LNASI and ESI, CSI, SSI and V-EASI methods on instrumental conditions, applied temperature and observed charge states for the multiply charged proteins, shows that the LNASI method produces the good quality spectra of amino acid clusters at ambient conditions without applied any electric field and heat. To date, we believe that the LNASI method is the most simple, low cost and provided an alternative paradigm for production of multiply charged ions by LNASI MS, just as ESI-like ions yet no need for applying any electrical field and it could be operated at low temperature for generation of highly charged protein/peptide ions. Copyright © 2012 Elsevier B.V. All rights reserved.

Self-Fourier functions and coherent laser combination

International Nuclear Information System (INIS)

Corcoran, C J; Pasch, K A

2004-01-01

The Gaussian and Comb functions are generally quoted as being the two basic functions that are their own Fourier transforms. In 1991, Caola presented a recipe for generating functions that are their own Fourier transforms by symmetrizing any transformable function and then adding its own Fourier transform to it. In this letter, we present a new method for generating a set of functions that are exactly their own Fourier transforms, and which have direct application to laser cavity design for a wide variety of applications. The generated set includes the Gaussian and Comb functions as special cases and forms a continuous bridge of functions between them. The new generating method uses the Gaussian and Comb functions as bases and does not rely on the Fourier operator itself. This self-Fourier function promises to be particularly useful in high-power laser design through coherent laser beam combination. Although these results are presented in a single dimension as with a linear array, the results are equally valid in two dimensions. (letter to the editor)

Content adaptive illumination for Fourier ptychography.

Science.gov (United States)

Bian, Liheng; Suo, Jinli; Situ, Guohai; Zheng, Guoan; Chen, Feng; Dai, Qionghai

2014-12-01

Fourier ptychography (FP) is a recently reported technique, for large field-of-view and high-resolution imaging. Specifically, FP captures a set of low-resolution images, under angularly varying illuminations, and stitches them together in the Fourier domain. One of FP's main disadvantages is its long capturing process, due to the requisite large number of incident illumination angles. In this Letter, utilizing the sparsity of natural images in the Fourier domain, we propose a highly efficient method, termed adaptive Fourier ptychography (AFP), which applies content adaptive illumination for FP, to capture the most informative parts of the scene's spatial spectrum. We validate the effectiveness and efficiency of the reported framework, with both simulated and real experiments. Results show that the proposed AFP could shorten the acquisition time of conventional FP, by around 30%-60%.

(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

Experiment study on the thick GEM-like multiplier for X-ray photoelectrons energy deposition gaining

International Nuclear Information System (INIS)

Zhu Pengfei; Ye Yan; Long Yan; Cao Ningxiang; Jia Xing; Li Jianfeng

2009-01-01

The GEM is a novel detector with high gain,high time and location resolution. Imitating the structure of the GEM, a thick GEM-like multiplier which has the similar function with that of the GEM is designed and manufactured. The characteristics of the thick GEM-like multiplier increasing electron energy deposition in absorbing medium has been experimentally studied. The results indicate that the energy deposition gain of x-ray photoelectron in medium is apparent, and the maximum energy deposition can increase by more than 40%. Some suggestions of further increasing the energy deposition are given, and the future application of the way of increasing the x-ray photoelectron energy deposition by the thick GEM-like multiplier in hard x-ray imaging is prospected. (authors)

Input/output Buffer based Vedic Multiplier Design for Thermal Aware Energy Efficient Digital Signal Processing on 28nm FPGA

DEFF Research Database (Denmark)

Goswami, Kavita; Pandey, Bishwajeet; Hussain, Dil muhammed Akbar

2016-01-01

Multiplier is used for multiplication of a signal and a constant in digital signal processing (DSP). 28nm technology based Vedic multiplier is implemented with use of VHDL HDL, Xilinx ISE, Kintex-7 FPGA and XPower Analyzer. Vedic multiplier gain speed improvements by parallelizing the generation...... Programmable Gate Array (FPGA) in order to reduce the development cost. The development cost for Application Specific Integrated Circuits (ASICs) are high in compare to FPGA. Selection of the most energy efficient IO standards in place of signal gating is the main design methodology for design of energy...... efficient Vedic multiplier.There is 68.51%, 69.86%, 74.65%, and 78.39% contraction in total power of Vedic multiplier on 28nm Kintex-7 FPGA, when we use HSTL_II in place of HSTL_II_DCI_18 at 56.7oC, 53.5oC, 40oC and 21oC respectively....

On the design of a radix-10 online floating-point multiplier

Science.gov (United States)

McIlhenny, Robert D.; Ercegovac, Milos D.

2009-08-01

This paper describes an approach to design and implement a radix-10 online floating-point multiplier. An online approach is considered because it offers computational flexibility not available with conventional arithmetic. The design was coded in VHDL and compiled, synthesized, and mapped onto a Virtex 5 FPGA to measure cost in terms of LUTs (look-up-tables) as well as the cycle time and total latency. The routing delay which was not optimized is the major component in the cycle time. For a rough estimate of the cost/latency characteristics, our design was compared to a standard radix-2 floating-point multiplier of equivalent precision. The results demonstrate that even an unoptimized radix-10 online design is an attractive implementation alternative for FPGA floating-point multiplication.

Multiplier effects and government assistance to energy megaprojects: An application to Hibernia

International Nuclear Information System (INIS)

Feehan, J.P.; Locke, L.W.

1993-01-01

Energy megaprojects typically require several years to construct and entail substantial costs. These costs, in the forms of employment, capital equipment and material inputs, are sometimes viewed as benefits. Moreover, the expenditures on these inputs can induce further increases in employment and income. On the basis of these project-specific and induced effects, government assistance is sometimes sought. The very limiting circumstances under which such government aid is justified are described. Multiplier effects only become relevant if private expenditure would not otherwise occur in some form in the economy. There are contractionary multiplier effects associated with the imposition of taxes to finance the project, and so the two opposing forces may be largely offsetting. Government assistance can only be justified in the presence of unemployment, and where the multiplier effects are large. When these criteria are applied to the Hibernia project, it is found that the project does not generate employment and income effects that are large relative to the total expenditure, or even relative to the level of federal government assistance. The job creation argument for the justification of government assistance to the Hibernia project is very weak. 18 refs., 1 tab

Low-order-mode harmonic multiplying gyrotron traveling-wave amplifier in W band

International Nuclear Information System (INIS)

Yeh, Y. S.; Chen, C. H.; Yang, S. J.; Lai, C. H.; Lin, T. Y.; Lo, Y. C.; Hong, J. W.; Hung, C. L.; Chang, T. H.

2012-01-01

Harmonic multiplying gyrotron traveling-wave amplifiers (gyro-TWAs) allow for magnetic field reduction and frequency multiplication. To avoid absolute instabilities, this work proposes a W-band harmonic multiplying gyro-TWA operating at low-order modes. By amplifying a fundamental harmonic TE 11 drive wave, the second harmonic component of the beam current initiates a TE 21 wave to be amplified. Absolute instabilities in the gyro-TWA are suppressed by shortening the interaction circuit and increasing wall losses. Simulation results reveal that compared with Ka-band gyro-TWTs, the lower wall losses effectively suppress absolute instabilities in the W-band gyro-TWA. However, a global reflective oscillation occurs as the wall losses decrease. Increasing the length or resistivity of the lossy section can reduce the feedback of the oscillation to stabilize the amplifier. The W-band harmonic multiplying gyro-TWA is predicted to yield a peak output power of 111 kW at 98 GHz with an efficiency of 25%, a saturated gain of 26 dB, and a bandwidth of 1.6 GHz for a 60 kV, 7.5 A electron beam with an axial velocity spread of 8%.

Electronic de-multipliers II (ring-shape systems); Demultiplieurs electroniques II (systeme en anneau)

Energy Technology Data Exchange (ETDEWEB)

Raievski, V

1948-09-01

This report describes a new type of ring-shape fast electronic counter (de-multiplier) with a resolution capacity equivalent to the one made by Regener (Rev. of Scientific Instruments USA 1946, 17, 180-89) but requiring two-times less electronic valves. This report follows the general description of electronic de-multipliers made by J. Ailloud (CEA--001). The ring comprises 5 flip-flop circuits with two valves each. The different elements of the ring are calculated with enough details to allow the transfer of this calculation to different valve types. (J.S.)

Electronic de-multipliers; Demultiplicateurs electroniques

Energy Technology Data Exchange (ETDEWEB)

Ailloud, J

1948-07-01

The counting of a huge number of events, randomly or periodically distributed, requires the use of electronic counters which can work with a flow of up to 500000 events per second, while mechanical systems have a much lower resolution which leads to an important percentage of losses (non-counted events). Thus, hybrid systems are generally used which comprise an electronic part with fast counting capabilities but low recording capacities, and a mechanical part for the recording of the successive resets of the electronic part. This report describes the basic elementary circuits of these electronic counters (de-multipliers): dividers by 2 and 5 and flip-flop circuits using triode and pentode valves for the counting of events in the decimal system. (J.S.)

Fourier phasing with phase-uncertain mask

International Nuclear Information System (INIS)

Fannjiang, Albert; Liao, Wenjing

2013-01-01

Fourier phasing is the problem of retrieving Fourier phase information from Fourier intensity data. The standard Fourier phase retrieval (without a mask) is known to have many solutions which cause the standard phasing algorithms to stagnate and produce wrong or inaccurate solutions. In this paper Fourier phase retrieval is carried out with the introduction of a randomly fabricated mask in measurement and reconstruction. Highly probable uniqueness of solution, up to a global phase, was previously proved with exact knowledge of the mask. Here the uniqueness result is extended to the case where only rough information about the mask’s phases is assumed. The exponential probability bound for uniqueness is given in terms of the uncertainty-to-diversity ratio of the unknown mask. New phasing algorithms alternating between the object update and the mask update are systematically tested and demonstrated to have the capability of recovering both the object and the mask (within the object support) simultaneously, consistent with the uniqueness result. Phasing with a phase-uncertain mask is shown to be robust with respect to the correlation in the mask as well as the Gaussian and Poisson noises. (paper)

Detection of differential item functioning using Lagrange multiplier tests

NARCIS (Netherlands)

Glas, Cornelis A.W.

1998-01-01

Abstract: In the present paper it is shown that differential item functioning can be evaluated using the Lagrange multiplier test or Rao’s efficient score test. The test is presented in the framework of a number of IRT models such as the Rasch model, the OPLM, the 2-parameter logistic model, the

Detection of differential item functioning using Lagrange multiplier tests

NARCIS (Netherlands)

Glas, Cornelis A.W.

1996-01-01

In this paper it is shown that differential item functioning can be evaluated using the Lagrange multiplier test or C. R. Rao's efficient score test. The test is presented in the framework of a number of item response theory (IRT) models such as the Rasch model, the one-parameter logistic model, the

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

Determination of Ultimate Torque for Multiply Connected Cross Section Rod

Directory of Open Access Journals (Sweden)

V. L. Danilov

2015-01-01

Full Text Available The aim of this work is to determine load-carrying capability of the multiply cross-section rod. This calculation is based on the model of the ideal plasticity of the material, so that the desired ultimate torque is a torque at which the entire cross section goes into a plastic state.The article discusses the cylindrical multiply cross-section rod. To satisfy the equilibrium equation and the condition of plasticity simultaneously, two stress function Ф and φ are introduced. By mathematical transformations it has been proved that Ф is constant along the path, and a formula to find its values on the contours has been obtained. The paper also presents the rationale of the line of stress discontinuity and obtained relationships, which allow us to derive the equations break lines for simple interaction of neighboring circuits, such as two lines, straight lines and circles, circles and a different sign of the curvature.After substitution into the boundary condition at the end of the stress function Ф and mathematical transformations a formula is obtained to determine the ultimate torque for the multiply cross-section rod.Using the doubly connected cross-section and three-connected cross-section rods as an example the application of the formula of ultimate torque is studied.For doubly connected cross-section rod, the paper offers a formula of the torque versus the radius of the rod, the aperture radius and the distance between their centers. It also clearly demonstrates the torque dependence both on the ratio of the radii and on the displacement of hole. It is shown that the value of the torque is more influenced by the displacement of hole, rather than by the ratio of the radii.For the three-connected cross-section rod the paper shows the integration feature that consists in selection of a coordinate system. As an example, the ultimate torque is found by two methods: analytical one and 3D modeling. The method of 3D modeling is based on the Nadai�

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

Mixed Analog/Digital Matrix-Vector Multiplier for Neural Network Synapses

DEFF Research Database (Denmark)

Lehmann, Torsten; Bruun, Erik; Dietrich, Casper

1996-01-01

In this work we present a hardware efficient matrix-vector multiplier architecture for artificial neural networks with digitally stored synapse strengths. We present a novel technique for manipulating bipolar inputs based on an analog two's complements method and an accurate current rectifier...

Optimization of Passive Voltage Multipliers for Fast Start-up and Multi-voltage Power Supplies in Electromagnetic Energy Harvesting Systems

Science.gov (United States)

Yang, G.; Stark, B. H.; Burrow, S. G.; Hollis, S. J.

2014-11-01

This paper demonstrates the use of passive voltage multipliers for rapid start-up of sub-milliwatt electromagnetic energy harvesting systems. The work describes circuit optimization to make as short as possible the transition from completely depleted energy storage to the first powering-up of an actively controlled switched-mode converter. The dependency of the start-up time on component parameters and topologies is derived by simulation and experimentation. The resulting optimized multiplier design reduces the start-up time from several minutes to 1 second. An additional improvement uses the inherent cascade structure of the voltage multiplier to power sub-systems at different voltages. This multi-rail start-up is shown to reduce the circuit losses of the active converter by 72% with respect to the optimized single-rail system. The experimental results provide insight into the multiplier's transient behaviour, including circuit interactions, in a complete harvesting system, and offer important information to optimize voltage multipliers for rapid start-up.

Optimization of Passive Voltage Multipliers for Fast Start-up and Multi-voltage Power Supplies in Electromagnetic Energy Harvesting Systems

International Nuclear Information System (INIS)

Yang, G; Stark, B H; Burrow, S G; Hollis, S J

2014-01-01

This paper demonstrates the use of passive voltage multipliers for rapid start-up of sub-milliwatt electromagnetic energy harvesting systems. The work describes circuit optimization to make as short as possible the transition from completely depleted energy storage to the first powering-up of an actively controlled switched-mode converter. The dependency of the start-up time on component parameters and topologies is derived by simulation and experimentation. The resulting optimized multiplier design reduces the start-up time from several minutes to 1 second. An additional improvement uses the inherent cascade structure of the voltage multiplier to power sub-systems at different voltages. This multi-rail start-up is shown to reduce the circuit losses of the active converter by 72% with respect to the optimized single-rail system. The experimental results provide insight into the multiplier's transient behaviour, including circuit interactions, in a complete harvesting system, and offer important information to optimize voltage multipliers for rapid start-up

Hyperbolic Cross Truncations for Stochastic Fourier Cosine Series

Science.gov (United States)

Zhang, Zhihua

2014-01-01

Based on our decomposition of stochastic processes and our asymptotic representations of Fourier cosine coefficients, we deduce an asymptotic formula of approximation errors of hyperbolic cross truncations for bivariate stochastic Fourier cosine series. Moreover we propose a kind of Fourier cosine expansions with polynomials factors such that the corresponding Fourier cosine coefficients decay very fast. Although our research is in the setting of stochastic processes, our results are also new for deterministic functions. PMID:25147842

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…

Fiscal multipliers over the growth cycle : evidence from Malaysia

OpenAIRE

Rafiq, Sohrab; Zeufack, Albert

2012-01-01

This paper explores the stabilisation properties of fiscal policy in Malaysia using a model incorporating nonlinearities into the dynamic relationship between fiscal policy and real economic activity over the growth cycle. The paper also investigates how output multipliers for government purchases may alter for different components of government spending. The authors find that fiscal polic...

Optimized GF(2k) ONB type I multiplier architecture based on the Massey-Omura multiplication pattern

International Nuclear Information System (INIS)

Fournaris, A P; Koufopavlou, O

2005-01-01

Multiplication in GF(2 k ) finite fields is becoming rapidly a very promising solution for fast, small, efficient binary algorithms designed for hardware applications. GF(2 k ) finite fields defined over optimal normal bases (ONB) can be very advantageous in term of gates number and multiplication time delay. Many ONB multipliers works have been proposed that use the Massey-Omura multiplication pattern. In this paper, a method for designing type I optimal normal basis multipliers and an optimal normal basis (ONB) type I multiplier hardware architecture is proposed that, through parallelism and pairing categorization of the ONB multiplication table matrix, achieves very interesting results in terms of gate number and multiplication time delay

A Note on Fourier and the Greenhouse Effect

OpenAIRE

Postma, Joseph E.

2015-01-01

Joseph Fourier's discovery of the greenhouse effect is discussed and is compared to the modern conception of the greenhouse effect. It is confirmed that what Fourier discovered is analogous to the modern concept of the greenhouse effect. However, the modern concept of the greenhouse effect is found to be based on a paradoxical analogy to Fourier's greenhouse work and so either Fourier's greenhouse work, the modern conception of the greenhouse effect, or the modern definition of heat is incorr...

Three dimensional image reconstruction in the Fourier domain

International Nuclear Information System (INIS)

Stearns, C.W.; Chesler, D.A.; Brownell, G.L.

1987-01-01

Filtered backprojection reconstruction algorithms are based upon the relationship between the Fourier transform of the imaged object and the Fourier transforms of its projections. A new reconstruction algorithm has been developed which performs the image assembly operation in Fourier space, rather than in image space by backprojection. This represents a significant decrease in the number of operations required to assemble the image. The new Fourier domain algorithm has resolution comparable to the filtered backprojection algorithm, and, after correction by a pointwise multiplication, demonstrates proper recovery throughout image space. Although originally intended for three-dimensional imaging applications, the Fourier domain algorithm can also be developed for two-dimensional imaging applications such as planar positron imaging systems

Fourier techniques and applications

CERN Document Server

1985-01-01

The first systematic methods of Fourier analysis date from the early eighteenth century with the work of Joseph Fourier on the problem of the flow of heat. (A brief history is contained in the first paper.) Given the initial tempera­ ture at all points of a region, the problem was to determine the changes in the temperature distribution over time. Understanding and predicting these changes was important in such areas as the handling of metals and the determination of geological and atmospheric temperatures. Briefly, Fourier noticed that the solution of the heat diffusion problem was simple if the initial temperature dis­ tribution was sinusoidal. He then asserted that any distri­ bution can be decomposed into a sum of sinusoids, these being the harmonics of the original function. This meant that the general solution could now be obtained by summing the solu­ tions of the component sinusoidal problems. This remarkable ability of the series of sinusoids to describe all "reasonable" functions, the sine qua n...

Multi-MW K-Band Harmonic Multiplier: RF Source For High-Gradient Accelerator R & D

Science.gov (United States)

Solyak, N. A.; Yakovlev, V. P.; Kazakov, S. Yu.; Hirshfield, J. L.

2009-01-01

A preliminary design is presented for a two-cavity harmonic multiplier, intended as a high-power RF source for use in experiments aimed at developing high-gradient structures for a future collider. The harmonic multiplier is to produce power at selected frequencies in K-band (18-26.5 GHz) using as an RF driver an XK-5 S-band klystron (2.856 GHz). The device is to be built with a TE111 rotating mode input cavity and interchangeable output cavities running in the TEn11 rotating mode, with n = 7,8,9 at 19.992, 22.848, and 25.704 GHz. An example for a 7th harmonic multiplier is described, using a 250 kV, 20 A injected laminar electron beam; with 10 MW of S-band drive power, 4.7 MW of 20-GHz output power is predicted. Details are described of the magnetic circuit, cavities, and output coupler.

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

Best approximation of the Dunkl Multiplier Operators Tk,ℓ,m

Directory of Open Access Journals (Sweden)

Fethi Soltani

2015-03-01

Full Text Available We study some class of Dunkl multiplier operators Tk,ℓ,m; and we give for them an application of the theory of reproducing kernels to the Tikhonov regularization,which gives the best approximation of the operators Tk,ℓ,m on a Hilbert spaces Hskℓ.

Time-area efficient multiplier-free filter architectures for FPGA implementation

DEFF Research Database (Denmark)

Shajaan, Mohammad; Nielsen, Karsten; Sørensen, John Aasted

1995-01-01

Simultaneous design of multiplier-free filters and their hardware implementation in Xilinx field programmable gate array (XC4000) is presented. The filter synthesis method is a new approach based on cascade coupling of low order sections. The complexity of the design algorithm is 𝒪 (filter o...

Ultra-low-power, class-AB, CMOS four-quadrant current multiplier

NARCIS (Netherlands)

Sawigun, C.; Serdijn, W.A.

2009-01-01

A class-AB four-quadrant current multiplier constituted by a class-AB current amplifier and a current splitter which can handle input signals in excess of ten times the bias current is presented. The proposed circuit operation is based on the exponential characteristic of BJTs or subthreshold

Imaging moving objects from multiply scattered waves and multiple sensors

International Nuclear Information System (INIS)

Miranda, Analee; Cheney, Margaret

2013-01-01

In this paper, we develop a linearized imaging theory that combines the spatial, temporal and spectral components of multiply scattered waves as they scatter from moving objects. In particular, we consider the case of multiple fixed sensors transmitting and receiving information from multiply scattered waves. We use a priori information about the multipath background. We use a simple model for multiple scattering, namely scattering from a fixed, perfectly reflecting (mirror) plane. We base our image reconstruction and velocity estimation technique on a modification of a filtered backprojection method that produces a phase-space image. We plot examples of point-spread functions for different geometries and waveforms, and from these plots, we estimate the resolution in space and velocity. Through this analysis, we are able to identify how the imaging system depends on parameters such as bandwidth and number of sensors. We ultimately show that enhanced phase-space resolution for a distribution of moving and stationary targets in a multipath environment may be achieved using multiple sensors. (paper)

Closing of Coster-Kronig transitions in multiply ionised gold atoms

International Nuclear Information System (INIS)

Banas, D.; Braziewicz, J.; Czarnota, M.; Fijal, I.; Jaskola, M.; Korman, A.; Kretschmer, W.; Pajek, M.; Semaniak, J.

2003-01-01

The paper discusses the effect of closing of L- and M-shell Coster-Kronig (CK) transitions in multiply ionised Au atoms, for which the selected CK transitions become energetically forbidden. This effect plays an important role when the Coster-Kronig energy for single-hole configuration is relatively low, being comparable with a change of the electronic binding energies in multiply ionised atom. We show, by using a simplified model, that for gold the effect of closing of CK transitions occurs for strong L 1 -L 3 M 4,5 transition for the L 1 -subshell as well as the M 3 -M 5 N 6,7 and M 4 -M 5 O 3,4 CK transitions for the M 3 - and M 4 -subshell, respectively. We demonstrate that the discussed effect of closing CK transitions substantially changes the X-ray fluorescence and Coster-Kronig yields and thus has to be considered in interpretation of X-rays excited by heavy ion impact

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

Fourier plane imaging microscopy

Energy Technology Data Exchange (ETDEWEB)

Dominguez, Daniel, E-mail: daniel.dominguez@ttu.edu; Peralta, Luis Grave de [Department of Physics, Texas Tech University, Lubbock, Texas 79409 (United States); Nano Tech Center, Texas Tech University, Lubbock, Texas 79409 (United States); Alharbi, Nouf; Alhusain, Mdhaoui [Department of Physics, Texas Tech University, Lubbock, Texas 79409 (United States); Bernussi, Ayrton A. [Nano Tech Center, Texas Tech University, Lubbock, Texas 79409 (United States); Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, Texas 79409 (United States)

2014-09-14

We show how the image of an unresolved photonic crystal can be reconstructed using a single Fourier plane (FP) image obtained with a second camera that was added to a traditional compound microscope. We discuss how Fourier plane imaging microscopy is an application of a remarkable property of the obtained FP images: they contain more information about the photonic crystals than the images recorded by the camera commonly placed at the real plane of the microscope. We argue that the experimental results support the hypothesis that surface waves, contributing to enhanced resolution abilities, were optically excited in the studied photonic crystals.

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

Robust formation control of marine surface craft using Lagrange multipliers

DEFF Research Database (Denmark)

Ihle, Ivar-Andre F.; Jouffroy, Jerome; Fossen, Thor I.

2006-01-01

This paper presents a formation modelling scheme based on a set of inter-body constraint functions and Lagrangian multipliers. Formation control for a °eet of marine craft is achieved by stabilizing the auxiliary constraints such that the desired formation con¯guration appears. In the proposed fr...

An introduction to Fourier series and integrals

CERN Document Server

Seeley, Robert T

2006-01-01

This compact guide emphasizes the relationship between physics and mathematics, introducing Fourier series in the way that Fourier himself used them: as solutions of the heat equation in a disk. 1966 edition.

A New Approach for the Discovery of Antibiotics by Targeting Non-Multiplying Bacteria: A Novel Topical Antibiotic for Staphylococcal Infections

Science.gov (United States)

Hu, Yanmin; Shamaei-Tousi, Alireza; Liu, Yingjun; Coates, Anthony

2010-01-01

In a clinical infection, multiplying and non-multiplying bacteria co-exist. Antibiotics kill multiplying bacteria, but they are very inefficient at killing non-multipliers which leads to slow or partial death of the total target population of microbes in an infected tissue. This prolongs the duration of therapy, increases the emergence of resistance and so contributes to the short life span of antibiotics after they reach the market. Targeting non-multiplying bacteria from the onset of an antibiotic development program is a new concept. This paper describes the proof of principle for this concept, which has resulted in the development of the first antibiotic using this approach. The antibiotic, called HT61, is a small quinolone-derived compound with a molecular mass of about 400 Daltons, and is active against non-multiplying bacteria, including methicillin sensitive and resistant, as well as Panton-Valentine leukocidin-carrying Staphylococcus aureus. It also kills mupirocin resistant MRSA. The mechanism of action of the drug is depolarisation of the cell membrane and destruction of the cell wall. The speed of kill is within two hours. In comparison to the conventional antibiotics, HT61 kills non-multiplying cells more effectively, 6 logs versus less than one log for major marketed antibiotics. HT61 kills methicillin sensitive and resistant S. aureus in the murine skin bacterial colonization and infection models. No resistant phenotype was produced during 50 serial cultures over a one year period. The antibiotic caused no adverse affects after application to the skin of minipigs. Targeting non-multiplying bacteria using this method should be able to yield many new classes of antibiotic. These antibiotics may be able to reduce the rate of emergence of resistance, shorten the duration of therapy, and reduce relapse rates. PMID:20676403

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.

Enhanced fuel production in thorium/lithium hybrid blankets utilizing uranium multipliers

International Nuclear Information System (INIS)

Pitulski, R.H.

1979-10-01

A consistent neutronics analysis is performed to determine the effectiveness of uranium bearing neutron multiplier zones on increasing the production of U 233 in thorium/lithium blankets for use in a tokamak fusion-fission hybrid reactor. The nuclear performance of these blankets is evaluated as a function of zone thicknesses and exposure by using the coupled transport burnup code ANISN-CINDER-HIC. Various parameters such as U 233 , Pu 239 , and H 3 production rates, the blanket energy multiplication, isotopic composition of the fuels, and neutron leakages into the various zones are evaluated during a 5 year (6 MW.y.m -2 ) exposure period. Although the results of this study were obtained for a tokomak magnetic fusion device, the qualitative behavior associated with the use of the uranium bearing neutron multiplier should be applicable to all fusion-fission hybrids

Preconditioned alternating direction method of multipliers for inverse problems with constraints

International Nuclear Information System (INIS)

Jiao, Yuling; Jin, Qinian; Lu, Xiliang; Wang, Weijie

2017-01-01

We propose a preconditioned alternating direction method of multipliers (ADMM) to solve linear inverse problems in Hilbert spaces with constraints, where the feature of the sought solution under a linear transformation is captured by a possibly non-smooth convex function. During each iteration step, our method avoids solving large linear systems by choosing a suitable preconditioning operator. In case the data is given exactly, we prove the convergence of our preconditioned ADMM without assuming the existence of a Lagrange multiplier. In case the data is corrupted by noise, we propose a stopping rule using information on noise level and show that our preconditioned ADMM is a regularization method; we also propose a heuristic rule when the information on noise level is unavailable or unreliable and give its detailed analysis. Numerical examples are presented to test the performance of the proposed method. (paper)

Fourier Series

Indian Academy of Sciences (India)

polynomials are dense in the class of continuous functions! The body of literature dealing with Fourier series has reached epic proportions over the last two centuries. We have only given the readers an outline of the topic in this article. For the full length episode we refer the reader to the monumental treatise of. A Zygmund.

Some Applications of Fourier's Great Discovery for Beginners

Science.gov (United States)

Kraftmakher, Yaakov

2012-01-01

Nearly two centuries ago, Fourier discovered that any periodic function of period T can be presented as a sum of sine waveforms of frequencies equal to an integer times the fundamental frequency [omega] = 2[pi]/T (Fourier's series). It is impossible to overestimate the importance of Fourier's discovery, and all physics or engineering students…

Observed travel times for Multiply-reflected ScS waves from a deep-focus earthquake

Directory of Open Access Journals (Sweden)

A. F. ESPISOSA

1966-06-01

Full Text Available Tlie deep-focus Argentinean earthquake of December 8
1962, generated multiply reflected ScS phases which were recorded very
clearly at stations of the IGY and the TJSC&GS standardized worldwide
networks and at Canadian stations. The data gathered from this earthquake
for the multiply-reflected ScS and sScS were used to construct the
travel times and to extend them to shorter epicentral distances. These
new data brought to light an error in published travel times for the 2(ScS
phase.

SIMAC - A phosphoproteomic strategy for the rapid separation of mono-phosphorylated from multiply phosphorylated peptides

DEFF Research Database (Denmark)

Thingholm, Tine E; Jensen, Ole N; Robinson, Phillip J

2008-01-01

spectrometric analysis, such as immobilized metal affinity chromatography or titanium dioxide the coverage of the phosphoproteome of a given sample is limited. Here we report a simple and rapid strategy - SIMAC - for sequential separation of mono-phosphorylated peptides and multiply phosphorylated peptides from...... and an optimized titanium dioxide chromatographic method. More than double the total number of identified phosphorylation sites was obtained with SIMAC, primarily from a three-fold increase in recovery of multiply phosphorylated peptides....

Angular distribution of 662keV multiply-Compton scattered gamma rays in copper

International Nuclear Information System (INIS)

Singh, Manpreet; Singh, Gurvinderjit; Sandhu, B.S.; Singh, Bhajan

2007-01-01

The angular distribution of multiple Compton scattering of 662keV gamma photons, obtained from six Curie 137 Cs source, incident on copper scatterer of varying thickness is studied experimentally in both the forward and backward hemispheres. The scattered photons are detected by a 51mmx51mm NaI(Tl) scintillation detector. The full-energy peak corresponding to singly scattered events is reconstructed analytically. We observe that the numbers of multiply scattered events, having same energy as in the singly scattered distribution, first increases with increase in target thickness and then saturate. The optimum thickness at which the multiply scattered events saturate is determined at different scattering angles

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)

Quasiparticle trapping and the quasiparticle multiplier

International Nuclear Information System (INIS)

Booth, N.E.

1987-01-01

Superconductors and in particular superconducting tunnel junctions can be used to detect phonons, electromagnetic radiation, x rays, and nuclear particles by the mechanism of Cooper-pair breaking to produce excess quasiparticles and phonons. We show that the sensitivity can be increased by a factor of 100 or more by trapping the quasiparticles in another superconductor of lower gap in the region of the tunnel junction. Moreover, if the ratio of the gap energies is >3 a multiplication process can occur due to the interaction of the relaxation phonons. This leads to the concept of the quasiparticle multiplier, a device which could have wider applications than the Gray effect transistor or the quiteron

Multiply charged ions of the oxygen - produced at interaction of laser radiation with two-element solids

International Nuclear Information System (INIS)

Bedilov, M.R.; Bedilov, R.M.; Kamalova, J.O.; Davletov, I.Yu.; Matnazarov, A.R.

2007-01-01

Full text: The interest to study of the oxygen multiply charged ions spectra produced at interaction laser radiation with one and two-element solids, is associate with possibility of creating laser and inertial thermonuclear syntheses, effective sources of multiply charged ions and nuclei atoms elements, plasma lasers, lasers on multiply charged transition, design of radiation-resistant materials and others. The present time many works is devoted to multiply charged ions, obtained from one element targets. Experimental results of study charge and energy spectra multiply charged ions of the oxygen, formed at interaction laser radiation with one and two-element solids are given in this work. Our experiments, we used installation, which is described in [1]. Neodymium laser had following parameters: wavelength 1.06 μm; intensity q = (0.1 h 1000) GW/sm 2 ; angle of incidence = 180. Were study one element Al, and two-element Al 2 O 3 , Y 2 O 3 targets by a diameter of 10 mm and thickness of 3 mm. Analysis obtained charge and energy spectra of multiply charged ions one (Al) and two-element (Al 2 O 3 , Y 2 O 3 ) targets depending on intensity of laser radiation and targets components reveal the following: - maximal charge number one element target (Al) at q 500 GW/sm 2 is equal Z max = 6 and all peaks corresponding to charge numbers Z = 1 - 6 well resolved, but two-element targets (Al 2 O 3 ) Z max ions Al decrease before 3. Also it is necessary to note that, Z max ions of the oxygen depend on target components. In case Al 2 O 3 and Y 2 O 3 maximal charge number of oxygen ions are equal Z max = 6 and 3, accordingly; - obtained charge and energy spectra of oxygen ions being included in two-element targets, are indicative of that, general regularities of the change Z max , E max and structures charge and energy spectra depending on q laser are saved. However they hang by target components; - common features and some differences of energy spectra multiply charged oxygen ions

GEM the gas electron multiplier

CERN Document Server

Sauli, Fabio

1997-01-01

We describe the basic structure and operation of a new device, the Gas Electron Multiplier. Consisting in a polymer foil, metal-clad on both sides and perforated by a high density of holes, the GEM mesh allows to pre-amplify charges released in the gas with good uniformity and energy. Coupled to a micro-strip plate, the pre-amplification element allows to preserve high rate capability and resolution at considerably lower operating voltages, thus completely eliminating discharges and instabilities. Several GEM grids can be operated in cascade; charge gains are large enough to allow detection of signals in the ionization mode on the last element, permitting the use of a simple printed circuit as read-out electrode. Two-dimensional read-out can then be easily implemented. A new generation of simple, reliable and cheap fast position sensitive detectors seems at hand.

Projective Fourier duality and Weyl quantization

International Nuclear Information System (INIS)

Aldrovandi, R.; Saeger, L.A.

1996-08-01

The Weyl-Wigner correspondence prescription, which makes large use of Fourier duality, is reexamined from the point of view of Kac algebras, the most general background for non-commutative Fourier analysis allowing for that property. It is shown how the standard Kac structure has to be extended in order to accommodate the physical requirements. An Abelian and a symmetric projective Kac algebras are shown to provide, in close parallel to the standard case, a new dual framework and a well-defined notion of projective Fourier duality for the group of translations on the plane. The Weyl formula arises naturally as an irreducible component of the duality mapping between these projective algebras. (author). 29 refs

Multiply ionization of diethyl ether clusters by 532 nm nanosecond laser: The influence of laser intensity and the electron energy distribution

International Nuclear Information System (INIS)

Zhang Nazhen; Wang Weiguo; Zhao Wuduo; Han Fenglei; Li Haiyang

2010-01-01

Graphical abstract: The formation mechanism for multiply charged ions (C q+ and O q+ (q = 2-4)) were investigated experimentally and theoretically using a dual polarity time-of-flight mass spectrometer when diethyl ether clusters interacted with nanosecond laser pulse. - Abstract: The formation mechanism for multiply charged ions (C q+ and O q+ (q = 2-4)) were investigated using a dual polarity time-of-flight mass spectrometer when diethyl ether clusters interacted with nanosecond laser pulse. The signal intensity of multiply charged ions and electron energy was measured experimentally. It was shown that the intensity of multiply charged ions increased about 50 times when laser intensity increased from 7.6 x 10 9 to 7.0 x 10 10 W/cm 2 , then saturated as laser intensity increased further. It is interesting that the evolution of the mean value of electron energy was same to that of multiply charged ions. The theoretical calculation showed the ionization potential of atomic ions could be significantly decreased due to the effect of Coulomb screening especially at low laser intensity. It indicated that the electron ionization combined with Coulomb screening effect could explain the production of multiply charged ions in nanosecond laser field.

Generalized Fourier slice theorem for cone-beam image reconstruction.

Science.gov (United States)

Zhao, Shuang-Ren; Jiang, Dazong; Yang, Kevin; Yang, Kang

2015-01-01

The cone-beam reconstruction theory has been proposed by Kirillov in 1961, Tuy in 1983, Feldkamp in 1984, Smith in 1985, Pierre Grangeat in 1990. The Fourier slice theorem is proposed by Bracewell 1956, which leads to the Fourier image reconstruction method for parallel-beam geometry. The Fourier slice theorem is extended to fan-beam geometry by Zhao in 1993 and 1995. By combining the above mentioned cone-beam image reconstruction theory and the above mentioned Fourier slice theory of fan-beam geometry, the Fourier slice theorem in cone-beam geometry is proposed by Zhao 1995 in short conference publication. This article offers the details of the derivation and implementation of this Fourier slice theorem for cone-beam geometry. Especially the problem of the reconstruction from Fourier domain has been overcome, which is that the value of in the origin of Fourier space is 0/0. The 0/0 type of limit is proper handled. As examples, the implementation results for the single circle and two perpendicular circle source orbits are shown. In the cone-beam reconstruction if a interpolation process is considered, the number of the calculations for the generalized Fourier slice theorem algorithm is O(N^4), which is close to the filtered back-projection method, here N is the image size of 1-dimension. However the interpolation process can be avoid, in that case the number of the calculations is O(N5).

Radial multipliers on reduced free products of operator algebras

DEFF Research Database (Denmark)

Haagerup, Uffe; Møller, Søren

2012-01-01

Let AiAi be a family of unital C¿C¿-algebras, respectively, of von Neumann algebras and ¿:N0¿C¿:N0¿C. We show that if a Hankel matrix related to ¿ is trace-class, then there exists a unique completely bounded map M¿M¿ on the reduced free product of the AiAi, which acts as a radial multiplier...

Corrected Fourier series and its application to function approximation

Directory of Open Access Journals (Sweden)

Qing-Hua Zhang

2005-01-01

Full Text Available Any quasismooth function f(x in a finite interval [0,x0], which has only a finite number of finite discontinuities and has only a finite number of extremes, can be approximated by a uniformly convergent Fourier series and a correction function. The correction function consists of algebraic polynomials and Heaviside step functions and is required by the aperiodicity at the endpoints (i.e., f(0≠f(x0 and the finite discontinuities in between. The uniformly convergent Fourier series and the correction function are collectively referred to as the corrected Fourier series. We prove that in order for the mth derivative of the Fourier series to be uniformly convergent, the order of the polynomial need not exceed (m+1. In other words, including the no-more-than-(m+1 polynomial has eliminated the Gibbs phenomenon of the Fourier series until its mth derivative. The corrected Fourier series is then applied to function approximation; the procedures to determine the coefficients of the corrected Fourier series are illustrated in detail using examples.

Auger transitions in singly and multiply ionized atoms

International Nuclear Information System (INIS)

Mehlhorn, W.

1978-01-01

Some recent progress in Auger and autoionizing electron spectrometry of free metal atoms and of multiply ionized atoms is reviewed. The differences which arise between the spectra of atoms in the gaseous and the solid state are due to solid state effects. This will be shown for Cd as an example. The super Coster-Kronig transitions 3p-3d 2 (hole notation) and Coster-Kronig transitions 3p-3d 4s have been measured and compared with free-atom calculations for free Zn atoms. The experimental width GAMMA(3p)=(2.1+-0.2)eV found for the free atom agrees with the value obtained for solid Zn but is considerably smaller than the theoretical value for the free atom. Autoionizing spectra of Na following an L-shell excitation or ionization by different particles are compared and discussed. The nonisotropic angular distribution of electrons from the transition 2p 5 3s 2 2 Psub(3/2)→2p 6 +e - is compared with theoretical calculations. Two examples for Auger spectrometry of multiply ionized atoms are given: (1) excitation of neon target atoms by light and heavy ions, and (2) excitation of projectile ions Be + and B + in single gas collisions with CH 4 . A strong alignment of the excited atoms has also been found here

Hardware Design and Implementation of Fixed-Width Standard and Truncated 4×4, 6×6, 8×8 and 12×12-BIT Multipliers Using Fpga

Science.gov (United States)

Rais, Muhammad H.

2010-06-01

This paper presents Field Programmable Gate Array (FPGA) implementation of standard and truncated multipliers using Very High Speed Integrated Circuit Hardware Description Language (VHDL). Truncated multiplier is a good candidate for digital signal processing (DSP) applications such as finite impulse response (FIR) and discrete cosine transform (DCT). Remarkable reduction in FPGA resources, delay, and power can be achieved using truncated multipliers instead of standard parallel multipliers when the full precision of the standard multiplier is not required. The truncated multipliers show significant improvement as compared to standard multipliers. Results show that the anomaly in Spartan-3 AN average connection and maximum pin delay have been efficiently reduced in Virtex-4 device.

Time-area efficient multiplier-free recursive filter architectures for FPGA implementation

DEFF Research Database (Denmark)

Shajaan, Mohammad; Sørensen, John Aasted

1996-01-01

Simultaneous design of multiplier-free recursive filters (IIR filters) and their hardware implementation in Xilinx field programmable gate array (XC4000) is presented. The hardware design methodology leads to high performance recursive filters with sampling frequencies in the interval 15-21 MHz (...

Multipliers on Generalized Mixed Norm Sequence Spaces

Directory of Open Access Journals (Sweden)

Oscar Blasco

2014-01-01

Full Text Available Given 1≤p,q≤∞ and sequences of integers (nkk and (nk′k such that nk≤nk′≤nk+1, the generalized mixed norm space ℓℐ(p,q is defined as those sequences (ajj such that ((∑j∈Ik‍|aj|p1/pk∈ℓq where Ik={j∈ℕ0 s.t. nk≤jmultipliers (ℓℐ(r,s,ℓ(u,v, for different sequences ℐ and of intervals in ℕ0, are determined.

Effects of tritium on electron multiplier performance

International Nuclear Information System (INIS)

Kerst, R.A.; Malinowski, M.E.

1980-01-01

In developing diagnostic instruments for fusion reactors, it is necessary to measure the effects of tritium contamination on channel electron multipliers (CEM). A CEM was exposed to T 2 pressures of up to 1.5 x 10 -1 Pa, with exposure quantities ranging up to 8800 Pa-s. The counting rate of the CEM is shown to consist of a prompt (Type I) signal caused by gas-phase tritium and a residual (Type II) signal, probably caused by near-surface tritium. The potential for using CEMs for observing the dynamics of tritium adsorption and absorption is discussed

Enhanced fuel production in thorium/lithium hybrid blankets utilizing uranium multipliers

Energy Technology Data Exchange (ETDEWEB)

Pitulski, R.H.

1979-10-01

A consistent neutronics analysis is performed to determine the effectiveness of uranium bearing neutron multiplier zones on increasing the production of U/sup 233/ in thorium/lithium blankets for use in a tokamak fusion-fission hybrid reactor. The nuclear performance of these blankets is evaluated as a function of zone thicknesses and exposure by using the coupled transport burnup code ANISN-CINDER-HIC. Various parameters such as U/sup 233/, Pu/sup 239/, and H/sup 3/ production rates, the blanket energy multiplication, isotopic composition of the fuels, and neutron leakages into the various zones are evaluated during a 5 year (6 MW.y.m/sup -2/) exposure period. Although the results of this study were obtained for a tokomak magnetic fusion device, the qualitative behavior associated with the use of the uranium bearing neutron multiplier should be applicable to all fusion-fission hybrids.

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

Shape Analysis of Planar Multiply-Connected Objects Using Conformal Welding.

Science.gov (United States)

Lok Ming Lui; Wei Zeng; Shing-Tung Yau; Xianfeng Gu

2014-07-01

Shape analysis is a central problem in the field of computer vision. In 2D shape analysis, classification and recognition of objects from their observed silhouettes are extremely crucial but difficult. It usually involves an efficient representation of 2D shape space with a metric, so that its mathematical structure can be used for further analysis. Although the study of 2D simply-connected shapes has been subject to a corpus of literatures, the analysis of multiply-connected shapes is comparatively less studied. In this work, we propose a representation for general 2D multiply-connected domains with arbitrary topologies using conformal welding. A metric can be defined on the proposed representation space, which gives a metric to measure dissimilarities between objects. The main idea is to map the exterior and interior of the domain conformally to unit disks and circle domains (unit disk with several inner disks removed), using holomorphic 1-forms. A set of diffeomorphisms of the unit circle S(1) can be obtained, which together with the conformal modules are used to define the shape signature. A shape distance between shape signatures can be defined to measure dissimilarities between shapes. We prove theoretically that the proposed shape signature uniquely determines the multiply-connected objects under suitable normalization. We also introduce a reconstruction algorithm to obtain shapes from their signatures. This completes our framework and allows us to move back and forth between shapes and signatures. With that, a morphing algorithm between shapes can be developed through the interpolation of the Beltrami coefficients associated with the signatures. Experiments have been carried out on shapes extracted from real images. Results demonstrate the efficacy of our proposed algorithm as a stable shape representation scheme.

Fan beam image reconstruction with generalized Fourier slice theorem.

Science.gov (United States)

Zhao, Shuangren; Yang, Kang; Yang, Kevin

2014-01-01

For parallel beam geometry the Fourier reconstruction works via the Fourier slice theorem (or central slice theorem, projection slice theorem). For fan beam situation, Fourier slice can be extended to a generalized Fourier slice theorem (GFST) for fan-beam image reconstruction. We have briefly introduced this method in a conference. This paper reintroduces the GFST method for fan beam geometry in details. The GFST method can be described as following: the Fourier plane is filled by adding up the contributions from all fanbeam projections individually; thereby the values in the Fourier plane are directly calculated for Cartesian coordinates such avoiding the interpolation from polar to Cartesian coordinates in the Fourier domain; inverse fast Fourier transform is applied to the image in Fourier plane and leads to a reconstructed image in spacial domain. The reconstructed image is compared between the result of the GFST method and the result from the filtered backprojection (FBP) method. The major differences of the GFST and the FBP methods are: (1) The interpolation process are at different data sets. The interpolation of the GFST method is at projection data. The interpolation of the FBP method is at filtered projection data. (2) The filtering process are done in different places. The filtering process of the GFST is at Fourier domain. The filtering process of the FBP method is the ramp filter which is done at projections. The resolution of ramp filter is variable with different location but the filter in the Fourier domain lead to resolution invariable with location. One advantage of the GFST method over the FBP method is in short scan situation, an exact solution can be obtained with the GFST method, but it can not be obtained with the FBP method. The calculation of both the GFST and the FBP methods are at O(N^3), where N is the number of pixel in one dimension.

Fourier spectral simulations for wake fields in conducting cavities

International Nuclear Information System (INIS)

Min, M.; Chin, Y.-H.; Fischer, P.F.; Chae, Y.-Chul; Kim, K.-J.

2007-01-01

We investigate Fourier spectral time-domain simulations applied to wake field calculations in two-dimensional cylindrical structures. The scheme involves second-order explicit leap-frogging in time and Fourier spectral approximation in space, which is obtained from simply replacing the spatial differentiation operator of the YEE scheme by the Fourier differentiation operator on nonstaggered grids. This is a first step toward investigating high-order computational techniques with the Fourier spectral method, which is relatively simple to implement.

Design and implementation in VHDL code of the two-dimensional fast Fourier transform for frequency filtering, convolution and correlation operations

Science.gov (United States)

Vilardy, Juan M.; Giacometto, F.; Torres, C. O.; Mattos, L.

2011-01-01

The two-dimensional Fast Fourier Transform (FFT 2D) is an essential tool in the two-dimensional discrete signals analysis and processing, which allows developing a large number of applications. This article shows the description and synthesis in VHDL code of the FFT 2D with fixed point binary representation using the programming tool Simulink HDL Coder of Matlab; showing a quick and easy way to handle overflow, underflow and the creation registers, adders and multipliers of complex data in VHDL and as well as the generation of test bench for verification of the codes generated in the ModelSim tool. The main objective of development of the hardware architecture of the FFT 2D focuses on the subsequent completion of the following operations applied to images: frequency filtering, convolution and correlation. The description and synthesis of the hardware architecture uses the XC3S1200E family Spartan 3E FPGA from Xilinx Manufacturer.

Multiplier method may be unreliable to predict the timing of temporary hemiepiphysiodesis for coronal angular deformity.

Science.gov (United States)

Wu, Zhenkai; Ding, Jing; Zhao, Dahang; Zhao, Li; Li, Hai; Liu, Jianlin

2017-07-10

The multiplier method was introduced by Paley to calculate the timing for temporary hemiepiphysiodesis. However, this method has not been verified in terms of clinical outcome measure. We aimed to (1) predict the rate of angular correction per year (ACPY) at the various corresponding ages by means of multiplier method and verify the reliability based on the data from the published studies and (2) screen out risk factors for deviation of prediction. A comprehensive search was performed in the following electronic databases: Cochrane, PubMed, and EMBASE™. A total of 22 studies met the inclusion criteria. If the actual value of ACPY from the collected date was located out of the range of the predicted value based on the multiplier method, it was considered as the deviation of prediction (DOP). The associations of patient characteristics with DOP were assessed with the use of univariate logistic regression. Only one article was evaluated as moderate evidence; the remaining articles were evaluated as poor quality. The rate of DOP was 31.82%. In the detailed individual data of included studies, the rate of DOP was 55.44%. The multiplier method is not reliable in predicting the timing for temporary hemiepiphysiodesis, even though it is prone to be more reliable for the younger patients with idiopathic genu coronal deformity.

Fourier series and orthogonal polynomials

CERN Document Server

Jackson, Dunham

2004-01-01

This text for undergraduate and graduate students illustrates the fundamental simplicity of the properties of orthogonal functions and their developments in related series. Starting with a definition and explanation of the elements of Fourier series, the text follows with examinations of Legendre polynomials and Bessel functions. Boundary value problems consider Fourier series in conjunction with Laplace's equation in an infinite strip and in a rectangle, with a vibrating string, in three dimensions, in a sphere, and in other circumstances. An overview of Pearson frequency functions is followe

High dynamic range isotope ratio measurements using an analog electron multiplier

Czech Academy of Sciences Publication Activity Database

Williams, P.; Lorinčík, Jan; Franzreb, K.; Herwig, R.

2013-01-01

Roč. 45, č. 1 (2013), s. 549-552 ISSN 0142-2421 R&D Projects: GA MŠk ME 894 Institutional support: RVO:67985882 Keywords : Isotope ratios * electron multiplier * dynamic range Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.393, year: 2013

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.

Fast Fourier single-pixel imaging via binary illumination.

Science.gov (United States)

Zhang, Zibang; Wang, Xueying; Zheng, Guoan; Zhong, Jingang

2017-09-20

Fourier single-pixel imaging (FSI) employs Fourier basis patterns for encoding spatial information and is capable of reconstructing high-quality two-dimensional and three-dimensional images. Fourier-domain sparsity in natural scenes allows FSI to recover sharp images from undersampled data. The original FSI demonstration, however, requires grayscale Fourier basis patterns for illumination. This requirement imposes a limitation on the imaging speed as digital micro-mirror devices (DMDs) generate grayscale patterns at a low refreshing rate. In this paper, we report a new strategy to increase the speed of FSI by two orders of magnitude. In this strategy, we binarize the Fourier basis patterns based on upsampling and error diffusion dithering. We demonstrate a 20,000 Hz projection rate using a DMD and capture 256-by-256-pixel dynamic scenes at a speed of 10 frames per second. The reported technique substantially accelerates image acquisition speed of FSI. It may find broad imaging applications at wavebands that are not accessible using conventional two-dimensional image sensors.

Four-gate transistor analog multiplier circuit

Science.gov (United States)

Mojarradi, Mohammad M. (Inventor); Blalock, Benjamin (Inventor); Cristoloveanu, Sorin (Inventor); Chen, Suheng (Inventor); Akarvardar, Kerem (Inventor)

2011-01-01

A differential output analog multiplier circuit utilizing four G.sup.4-FETs, each source connected to a current source. The four G.sup.4-FETs may be grouped into two pairs of two G.sup.4-FETs each, where one pair has its drains connected to a load, and the other par has its drains connected to another load. The differential output voltage is taken at the two loads. In one embodiment, for each G.sup.4-FET, the first and second junction gates are each connected together, where a first input voltage is applied to the front gates of each pair, and a second input voltage is applied to the first junction gates of each pair. Other embodiments are described and claimed.

Multiple images of our galaxy in closed, multiply connected cosmologies

International Nuclear Information System (INIS)

Fagundes, H.V.

1985-01-01

Friedmanian cosmology with multiply connected spatial sections allows multiple images of cosmic sources, in particular of the galaxy itself. This is illustrated with a specific example of a closed hyperbolic model and a brief mention of a spherical model. Such images may eventually become observable (or recognized as such), thus providing a new test of relativistic cosmology. (Author) [pt

Double Fourier analysis for Emotion Identification in Voiced Speech

International Nuclear Information System (INIS)

Sierra-Sosa, D.; Bastidas, M.; Ortiz P, D.; Quintero, O.L.

2016-01-01

We propose a novel analysis alternative, based on two Fourier Transforms for emotion recognition from speech. Fourier analysis allows for display and synthesizes different signals, in terms of power spectral density distributions. A spectrogram of the voice signal is obtained performing a short time Fourier Transform with Gaussian windows, this spectrogram portraits frequency related features, such as vocal tract resonances and quasi-periodic excitations during voiced sounds. Emotions induce such characteristics in speech, which become apparent in spectrogram time-frequency distributions. Later, the signal time-frequency representation from spectrogram is considered an image, and processed through a 2-dimensional Fourier Transform in order to perform the spatial Fourier analysis from it. Finally features related with emotions in voiced speech are extracted and presented. (paper)

Enhanced ground bounce noise reduction in a low-leakage CMOS multiplier

Science.gov (United States)

Verma, Bipin Kumar; Akashe, Shyam; Sharma, Sanjay

2015-09-01

In this paper, various parameters are used to reduce leakage power, leakage current and noise margin of circuits to enhance their performance. A multiplier is proposed with low-leakage current and low ground bounce noise for the microprocessor, digital signal processors (DSP) and graphics engines. The ground bounce noise problem appears when a conventional power-gating circuit transits from sleep-to-active mode. This paper discusses a reduction in leakage current in the stacking power-gating technique by three modes - sleep, active and sleep-to-active. The simulation results are performed on a 4 × 4 carry-save multiplier for leakage current, active power, leakage power and ground bounce noise, and comparison made for different nanoscales. Ground bounce noise is limited to 90%. The leakage current of the circuit is decimated up to 80% and the active power is reduced to 31%. We performed simulations using cadence virtuoso 180 and 45 nm at room temperature at various supply voltages.

Features of destruction of solids by laser radiation in process of formation of multiply charged ions

International Nuclear Information System (INIS)

Bedilov, R.M.; Bedilov, M.R.; Sabitov, M.M.; Matnazarov, A.; Niyozov, B.

2004-01-01

Full text: It is known, under interaction of laser radiation with solid surface a power density q > 0.01 W/cm 2 are observed destruction of a solid and issue of electrons, ions, neutrals, neutrons, plasmas, and also radiation in a wide ranges of a spectra. Despite of a plenty of works, devoted to study of processes of interaction, the studies of feature of destruction of solids by laser beam in process of formation multiply charged ions are insufficiently investigated. The results of study feature of destruction of solids by laser radiation in process of formation multiply charged ions are given in this work. In our experiments, we used the mass spectrometer with single-channel laser radiation. The laser installation had the following parameters: a power density of laser radiation q=(0.1-50) GW/cm 2 ; the angle of incidence a=18 deg. to the target surface Al, (W). It was obtained experimentally dynamics of morphology of destruction and also mass - charge and energy spectra of multiply charged ions formed under interaction of laser radiation with Al (W) in the intensity range q=(0.1-50) GW/cm 2 . These studies showed features of destruction Al(W) by laser radiation, i.e. invariable of value evaporation mass from a surface of a solid increase as the laser intensity q. But thus temperature a pair increases in accordance with increase of flow density of a laser radiation. Increase of temperature the pair gives in formation of multiply charged plasma. It is typical that, as q of the laser increases the maximum charge number of ions in laser plasma considerably increase and their energy spectra extend toward higher energies. For example, under q=0.1 GW/cm 2 and 50 GW/cm 2 the maximum charge number of ions Al (W) are equal to Z max = 1 and 7, respectively. From the experimental data obtained, we can conclude that, the formed multiply charged plasma practically completely absorption laser radiation and 'shielding' a target surface for various metals at power densities

On bifurcations of a system of cubic differential equations with an integrating multiplier singular along a second-order curve

Directory of Open Access Journals (Sweden)

Aleksandr Alekseev

2015-07-01

Full Text Available We establish necessary and sufficient conditions for existence of an integrating multiplier of a special form for systems of two cubic differential equations of the first order. We further study bifurcations of such systems with the change of parameters of their integrating multipliers.

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

Cluster-assistant generation of multiply charged atomic ions in nanosecond laser ionization of seeded methyl iodide beam

International Nuclear Information System (INIS)

Luo Xiaolin; Niu Dongmei; Kong Xianglei; Wen Lihua; Liang Feng; Pei Kemei; Wang Bin; Li Haiyang

2005-01-01

The photoionization of methyl iodide beam seeded in argon and helium is studied by time-of-flight mass spectrometry using a 25 ns, 532 nm Nd-YAG laser with intensities in the range of 2 x 10 10 -2 x 10 11 W/cm 2 . Multiply charged ions of I q+ (q = 2-3) and C 2+ with tens of eV kinetic energies have been observed when laser interacts with the middle part of the pulsed molecular beam, whose peak profiles are independent on the laser polarization directions. Strong evidences show that these ions are coming from the Coulomb explosion of multiply charged CH 3 I clusters, and laser induced inverse bremsstrahlung absorption of caged electrons plays a key role in the formation of multiply charged ions

Modeling Photo-multiplier Gain and Regenerating Pulse Height Data for Application Development

Science.gov (United States)

Aspinall, Michael D.; Jones, Ashley R.

2018-01-01

Systems that adopt organic scintillation detector arrays often require a calibration process prior to the intended measurement campaign to correct for significant performance variances between detectors within the array. These differences exist because of low tolerances associated with photo-multiplier tube technology and environmental influences. Differences in detector response can be corrected for by adjusting the supplied photo-multiplier tube voltage to control its gain and the effect that this has on the pulse height spectra from a gamma-only calibration source with a defined photo-peak. Automated methods that analyze these spectra and adjust the photo-multiplier tube bias accordingly are emerging for hardware that integrate acquisition electronics and high voltage control. However, development of such algorithms require access to the hardware, multiple detectors and calibration source for prolonged periods, all with associated constraints and risks. In this work, we report on a software function and related models developed to rescale and regenerate pulse height data acquired from a single scintillation detector. Such a function could be used to generate significant and varied pulse height data that can be used to integration-test algorithms that are capable of automatically response matching multiple detectors using pulse height spectra analysis. Furthermore, a function of this sort removes the dependence on multiple detectors, digital analyzers and calibration source. Results show a good match between the real and regenerated pulse height data. The function has also been used successfully to develop auto-calibration algorithms.

Extending Single-Molecule Microscopy Using Optical Fourier Processing

Science.gov (United States)

2015-01-01

This article surveys the recent application of optical Fourier processing to the long-established but still expanding field of single-molecule imaging and microscopy. A variety of single-molecule studies can benefit from the additional image information that can be obtained by modulating the Fourier, or pupil, plane of a widefield microscope. After briefly reviewing several current applications, we present a comprehensive and computationally efficient theoretical model for simulating single-molecule fluorescence as it propagates through an imaging system. Furthermore, we describe how phase/amplitude-modulating optics inserted in the imaging pathway may be modeled, especially at the Fourier plane. Finally, we discuss selected recent applications of Fourier processing methods to measure the orientation, depth, and rotational mobility of single fluorescent molecules. PMID:24745862

Time-resolved PHERMEX image restorations constrained with an additional multiply-exposed image

International Nuclear Information System (INIS)

Kruger, R.P.; Breedlove, J.R. Jr.; Trussell, H.J.

1978-06-01

There are a number of possible industrial and scientific applications of nanosecond cineradiographs. Although the technology exists to produce closely spaced pulses of x rays for this application, the quality of the time-resolved radiographs is severely limited. The limitations arise from the necessity of using a fluorescent screen to convert the transmitted x rays to light and then using electro-optical imaging systems to gate and to record the images with conventional high-speed cameras. It has been proposed that, in addition to the time-resolved images, a conventional multiply exposed radiograph be obtained. This report uses both PHERMEX and conventional photographic simulations to demonstrate that the additional information supplied by the multiply exposed radiograph can be used to improve the quality of digital image restorations of the time-resolved pictures over what could be achieved with the degraded images alone

Characterization of a prototype matrix of Silicon PhotoMultipliers

Energy Technology Data Exchange (ETDEWEB)

Dinu, N. [Laboratory of Linear Accelerator (LAL), IN2P3-CNRS, 91898 Orsay (France)], E-mail: dinu@lal.in2p3.fr; Barrillon, P.; Bazin, C. [Laboratory of Linear Accelerator (LAL), IN2P3-CNRS, 91898 Orsay (France); Belcari, N.; Bisogni, M.G. [Universita di Pisa, Dipartimento di Fisica ' E. Fermi' , 56127 Pisa (Italy); INFN, Sezione di Pisa, 56127 Pisa (Italy); Bondil-Blin, S. [Laboratory of Linear Accelerator (LAL), IN2P3-CNRS, 91898 Orsay (France); Boscardin, M. [Fondazione Bruno Kessler (FBK-irst), 38050 Trento (Italy); Chaumat, V. [Laboratory of Linear Accelerator (LAL), IN2P3-CNRS, 91898 Orsay (France); Collazuol, G. [Scuola Normale Superiore (SNS), 56127 Pisa (Italy); INFN, Sezione di Pisa, 56127 Pisa (Italy); De La Taille, C. [Laboratory of Linear Accelerator (LAL), IN2P3-CNRS, 91898 Orsay (France); Del Guerra, A. [Universita di Pisa, Dipartimento di Fisica ' E. Fermi' , 56127 Pisa (Italy); INFN, Sezione di Pisa, 56127 Pisa (Italy); Llosa, G. [Universita di Pisa, Dipartimento di Fisica ' E. Fermi' , 56127 Pisa (Italy); Marcatili, S. [Universita di Pisa, Dipartimento di Fisica ' E. Fermi' , 56127 Pisa (Italy); INFN, Sezione di Pisa, 56127 Pisa (Italy); Melchiorri, M.; Piemonte, C. [Fondazione Bruno Kessler (FBK-irst), 38050 Trento (Italy); Puill, V. [Laboratory of Linear Accelerator (LAL), IN2P3-CNRS, 91898 Orsay (France); Tarolli, A. [Fondazione Bruno Kessler (FBK-irst), 38050 Trento (Italy); Vagnucci, J.F. [Laboratory of Linear Accelerator (LAL), IN2P3-CNRS, 91898 Orsay (France); Zorzi, N. [Fondazione Bruno Kessler (FBK-irst), 38050 Trento (Italy)

2009-10-21

This work reports on the electrical as well as the optical characterizations of a prototype matrix of Silicon PhotoMultipliers (SiPM). The electrical test consists of the measurement of the static (breakdown voltage, quenching resistance, post-breakdown dark current) as well as the dynamic characteristics (gain, dark count rate). The optical test consists of the estimation of the photon detection efficiency as a function of wavelength as well as operation voltage.

Characterization of a prototype matrix of Silicon PhotoMultipliers

International Nuclear Information System (INIS)

Dinu, N.; Barrillon, P.; Bazin, C.; Belcari, N.; Bisogni, M.G.; Bondil-Blin, S.; Boscardin, M.; Chaumat, V.; Collazuol, G.; De La Taille, C.; Del Guerra, A.; Llosa, G.; Marcatili, S.; Melchiorri, M.; Piemonte, C.; Puill, V.; Tarolli, A.; Vagnucci, J.F.; Zorzi, N.

2009-01-01

This work reports on the electrical as well as the optical characterizations of a prototype matrix of Silicon PhotoMultipliers (SiPM). The electrical test consists of the measurement of the static (breakdown voltage, quenching resistance, post-breakdown dark current) as well as the dynamic characteristics (gain, dark count rate). The optical test consists of the estimation of the photon detection efficiency as a function of wavelength as well as operation voltage.

The gas electron multiplier (GEM)

CERN Document Server

Bouclier, Roger; Dominik, Wojciech; Hoch, M; Labbé, J C; Million, Gilbert; Ropelewski, Leszek; Sauli, Fabio; Sharma, A

1996-01-01

We describe operating priciples and results obtained with a new detector component: the Gas Electrons Multiplier (GEM). Consisting of a thin composite sheet with two metal layers separated by a thin insulator, and pierced by a regular matrix of open channels, the GEM electrode, inserted on the path of electrons in a gas detector, allows to transfer the charge with an amplification factor approaching ten. Uniform response and high rate capability are demonstrated. Coupled to another device, multiwire or micro-strip chamber, the GEM electrode permit to obtain higher gains or less critical operation; separation of the sensitive (conversion) volume and the detection volume has other advantages, as a built-in delay (useful for triggering purposes) and the possibility of applying high fields on the photo-cathode of ring imaging detectors to improve efficiency. Multiple GEM grids in the same gas volume allow to obtain large amplification factors in a succession of steps, leading to the realization of an effective ga...

The effects of multiply ionizing gamma irradiations on the xenobiotic metabolizing system in the liver of rats

International Nuclear Information System (INIS)

Zavodnik, L.B.; Buko, V.U.

2009-01-01

The aim of the work was the studying the effect of multiply low doses of gamma-irradiation in a total doze 1 and 2 Gy on processes lipid peroxidation and xenobiotics metabolizing in rat liver. It was shown the multiply irradiation causes the expressed activation of lipid peroxidation, by increase of TBARS level and dien conjugates. The system of microsomal oxidations was broken at the same time. (authors)

Spot Pricing When Lagrange Multipliers Are Not Unique

DEFF Research Database (Denmark)

Feng, Donghan; Xu, Zhao; Zhong, Jin

2012-01-01

Classical spot pricing theory is based on multipliers of the primal problem of an optimal market dispatch, i.e., the solution of the dual problem. However, the dual problem of market dispatch may yield multiple solutions. In these circumstances, spot pricing or any standard pricing practice based...... on a strict extension of the principles of spot pricing and surplus allocation, we propose a new pricing methodology that can yield unique, impartial, and robust solution. The new method has been analyzed and compared with other pricing approaches in accordance with spot pricing theory. Case studies support...

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.

A new VLSI complex integer multiplier which uses a quadratic-polynomial residue system with Fermat numbers

Science.gov (United States)

Shyu, H. C.; Reed, I. S.; Truong, T. K.; Hsu, I. S.; Chang, J. J.

1987-01-01

A quadratic-polynomial Fermat residue number system (QFNS) has been used to compute complex integer multiplications. The advantage of such a QFNS is that a complex integer multiplication requires only two integer multiplications. In this article, a new type Fermat number multiplier is developed which eliminates the initialization condition of the previous method. It is shown that the new complex multiplier can be implemented on a single VLSI chip. Such a chip is designed and fabricated in CMOS-Pw technology.

Studies of collision mechanisms in electron capture by slow multiply charged ions

International Nuclear Information System (INIS)

Gilbody, H B; McCullough, R W

2004-01-01

We review measurements based on translational energy spectroscopy which are being used to identify and assess the relative importance of the various collision mechanisms involved in one-electron capture by slow multiply charged ions in collisions with simple atoms and molecules

Structural brain network analysis in families multiply affected with bipolar I disorder

NARCIS (Netherlands)

Forde, Natalie J.; O'Donoghue, Stefani; Scanlon, Cathy; Emsell, Louise; Chaddock, Chris; Leemans, Alexander; Jeurissen, Ben; Barker, Gareth J.; Cannon, Dara M.; Murray, Robin M.; McDonald, Colm

2015-01-01

Disrupted structural connectivity is associated with psychiatric illnesses including bipolar disorder (BP). Here we use structural brain network analysis to investigate connectivity abnormalities in multiply affected BP type I families, to assess the utility of dysconnectivity as a biomarker and its

Content Adaptive Lagrange Multiplier Selection for Rate-Distortion Optimization in 3-D Wavelet-Based Scalable Video Coding

Directory of Open Access Journals (Sweden)

Ying Chen

2018-03-01

Full Text Available Rate-distortion optimization (RDO plays an essential role in substantially enhancing the coding efficiency. Currently, rate-distortion optimized mode decision is widely used in scalable video coding (SVC. Among all the possible coding modes, it aims to select the one which has the best trade-off between bitrate and compression distortion. Specifically, this tradeoff is tuned through the choice of the Lagrange multiplier. Despite the prevalence of conventional method for Lagrange multiplier selection in hybrid video coding, the underlying formulation is not applicable to 3-D wavelet-based SVC where the explicit values of the quantization step are not available, with on consideration of the content features of input signal. In this paper, an efficient content adaptive Lagrange multiplier selection algorithm is proposed in the context of RDO for 3-D wavelet-based SVC targeting quality scalability. Our contributions are two-fold. First, we introduce a novel weighting method, which takes account of the mutual information, gradient per pixel, and texture homogeneity to measure the temporal subband characteristics after applying the motion-compensated temporal filtering (MCTF technique. Second, based on the proposed subband weighting factor model, we derive the optimal Lagrange multiplier. Experimental results demonstrate that the proposed algorithm enables more satisfactory video quality with negligible additional computational complexity.

Study of the electric field inside microchannel plate multipliers

International Nuclear Information System (INIS)

Gatti, E.; Oba, K.; Rehak, P.

1982-01-01

Electric field inside high gain microchannel plate multipliers was studied. The calculations were based directly on the solution of the Maxwell equations applied to the microchannel plate (MCP) rather than on the conventional lumped RC model. The results are important to explain the performance of MCP's, (1) under a pulsed bias tension and, (2) at high rate conditions. The results were tested experimentally and a new method of MCP operation free from the positive ion feedback was demonstrated

Polarization of X rays of multiply charged ions in dense high-temperature plasma

NARCIS (Netherlands)

Baronova, EO; Dolgov, AN; Yakubovskii, LK

2004-01-01

The development of a method for studying the features of X-ray emission by multiply charged ions in a dense hot plasma is considered. These features are determined by the radiation polarization phenomenon.

The Growth Points of Regional Economy and Regression Estimation for Branch Investment Multipliers

Directory of Open Access Journals (Sweden)

Nina Pavlovna Goridko

2018-03-01

Full Text Available The article develops the methodology of using investment multipliers to identify growth points for a regional economy. The paper discusses various options for the assessment of multiplicative effects caused by investments in certain sectors of the economy. All calculations are carried out on the example of economy of the Republic of Tatarstan for the period 2005–2015. The instrument of regression modeling using the method of least squares, permits to estimate sectoral and cross-sectoral investment multipliers in the economy of the Republic of Tatarstan. Moreover, this method allows to assess the elasticity of gross output of regional economy and its individual sectors depending on investment in various sectors of the economy. Calculations results allowed to identify three growth points of the economy of the Republic of Tatarstan. They are mining industry, manufacturing industry and construction. The success of a particular industry or sub-industry in a country or a region should be measured not only by its share in macro-system’s gross output or value added, but also by the multiplicative effect that investments in the industry have on the development of other industries, on employment and on general national or regional product. In recent years, the growth of the Russian was close to zero. Thus, it is crucial to understand the structural consequences of the increasing investments in various sectors of the Russian economy. In this regard, the problems solved in the article are relevant for a number of countries and regions with a similar economic situation. The obtained results can be applied for similar estimations of investment multipliers as well as multipliers of government spending, and other components of aggregate demand in various countries and regions to identify growth points. Investments in these growth points will induce the greatest and the most evident increment of the outcome from the macro-system’s economic activities.

Projection-based stabilization of interface Lagrange multipliers in immersogeometric fluid-thin structure interaction analysis, with application to heart valve modeling.

Science.gov (United States)

Kamensky, David; Evans, John A; Hsu, Ming-Chen; Bazilevs, Yuri

2017-11-01

This paper discusses a method of stabilizing Lagrange multiplier fields used to couple thin immersed shell structures and surrounding fluids. The method retains essential conservation properties by stabilizing only the portion of the constraint orthogonal to a coarse multiplier space. This stabilization can easily be applied within iterative methods or semi-implicit time integrators that avoid directly solving a saddle point problem for the Lagrange multiplier field. Heart valve simulations demonstrate applicability of the proposed method to 3D unsteady simulations. An appendix sketches the relation between the proposed method and a high-order-accurate approach for simpler model problems.

Charge exchange and ionization in atom-multiply-charged ion collisions

International Nuclear Information System (INIS)

Presnyakov, L.P.; Uskov, D.B.

1988-01-01

This study investigates one-electron transitions to the continuous and discrete spectra induced by a collision of atom A and multiply-charged ion B +Z with nuclear charge Z > 3. An analytical method is developed the charge-exchange reaction; this method is a generalization of the decay model and the approximation of nonadiabatic coupling of two states that are used as limiting cases in the proposed approach

Harmonic analysis from Fourier to wavelets

CERN Document Server

Pereyra, Maria Cristina

2012-01-01

In the last 200 years, harmonic analysis has been one of the most influential bodies of mathematical ideas, having been exceptionally significant both in its theoretical implications and in its enormous range of applicability throughout mathematics, science, and engineering. In this book, the authors convey the remarkable beauty and applicability of the ideas that have grown from Fourier theory. They present for an advanced undergraduate and beginning graduate student audience the basics of harmonic analysis, from Fourier's study of the heat equation, and the decomposition of functions into sums of cosines and sines (frequency analysis), to dyadic harmonic analysis, and the decomposition of functions into a Haar basis (time localization). While concentrating on the Fourier and Haar cases, the book touches on aspects of the world that lies between these two different ways of decomposing functions: time-frequency analysis (wavelets). Both finite and continuous perspectives are presented, allowing for the introd...

Fourier analysis and boundary value problems

CERN Document Server

Gonzalez-Velasco, Enrique A

1996-01-01

Fourier Analysis and Boundary Value Problems provides a thorough examination of both the theory and applications of partial differential equations and the Fourier and Laplace methods for their solutions. Boundary value problems, including the heat and wave equations, are integrated throughout the book. Written from a historical perspective with extensive biographical coverage of pioneers in the field, the book emphasizes the important role played by partial differential equations in engineering and physics. In addition, the author demonstrates how efforts to deal with these problems have lead to wonderfully significant developments in mathematics.A clear and complete text with more than 500 exercises, Fourier Analysis and Boundary Value Problems is a good introduction and a valuable resource for those in the field.Key Features* Topics are covered from a historical perspective with biographical information on key contributors to the field* The text contains more than 500 exercises* Includes practical applicati...

Mathematical principles of signal processing Fourier and wavelet analysis

CERN Document Server

Brémaud, Pierre

2002-01-01

Fourier analysis is one of the most useful tools in many applied sciences. The recent developments of wavelet analysis indicates that in spite of its long history and well-established applications, the field is still one of active research. This text bridges the gap between engineering and mathematics, providing a rigorously mathematical introduction of Fourier analysis, wavelet analysis and related mathematical methods, while emphasizing their uses in signal processing and other applications in communications engineering. The interplay between Fourier series and Fourier transforms is at the heart of signal processing, which is couched most naturally in terms of the Dirac delta function and Lebesgue integrals. The exposition is organized into four parts. The first is a discussion of one-dimensional Fourier theory, including the classical results on convergence and the Poisson sum formula. The second part is devoted to the mathematical foundations of signal processing - sampling, filtering, digital signal proc...

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.

Effect of cooling on the efficiency of Schottky varactor frequency multipliers at millimeter waves

Science.gov (United States)

Louhi, Jyrki; Raiesanen, Antti; Erickson, Neal

1992-01-01

The efficiency of the Schottky diode multiplier can be increased by cooling the diode to 77 K. The main reason for better efficiency is the increased mobility of the free carriers. Because of that the series resistance decreases and a few dB higher efficiency can be expected at low input power levels. At high output frequencies and at high power levels, the current saturation decreases the efficiency of the multiplication. When the diode is cooled the maximum current of the diode increases and much more output power can be expected. There are also slight changes in the I-V characteristic and in the diode junction capacitance, but they have a negligible effect on the efficiency of the multiplier.

Reducing Approximation Error in the Fourier Flexible Functional Form

Directory of Open Access Journals (Sweden)

Tristan D. Skolrud

2017-12-01

Full Text Available The Fourier Flexible form provides a global approximation to an unknown data generating process. In terms of limiting function specification error, this form is preferable to functional forms based on second-order Taylor series expansions. The Fourier Flexible form is a truncated Fourier series expansion appended to a second-order expansion in logarithms. By replacing the logarithmic expansion with a Box-Cox transformation, we show that the Fourier Flexible form can reduce approximation error by 25% on average in the tails of the data distribution. The new functional form allows for nested testing of a larger set of commonly implemented functional forms.

Performance of gas electron multiplier (GEM) detector

International Nuclear Information System (INIS)

Han, S. H.; Moon, B. S.; Kim, Y. K.; Chung, C. E.; Kang, H. D.; Cho, H. S.

2002-01-01

We have investigated in detail the operating properties of Gas Electron Multiplier (GEM) detectors with a double conical and a cylindrical structure in a wide range of external fields and GEM voltages. With the double conical GEM, the gain gradually increased with time by 10%; whereas this surface charging was eliminated with the cylindrical GEM. Effective gains above 1000 were easily observed over a wide range of collection field strengths in a gas mixture of Ar/CO 2 (70/30). The transparency and electron collection efficiency were found to depend on the ratio of external field and the applied GEM voltage; the mutual influence of both drift and collection fields was found to be trivial

Screening retinal transplants with Fourier-domain OCT

Science.gov (United States)

Rao, Bin

2009-02-01

Transplant technologies have been studied for the recovery of vision loss from retinitis pigmentosa (RP) and age-related macular degeneration (AMD). In several rodent retinal degeneration models and in patients, retinal progenitor cells transplanted as layers to the subretinal space have been shown to restore or preserve vision. The methods for evaluation of transplants are expensive considering the large amount of animals. Alternatively, time-domain Stratus OCT was previously shown to be able to image the morphological structure of transplants to some extent, but could not clearly identify laminated transplants. The efficacy of screening retinal transplants with Fourier-domain OCT was studied on 37 S334ter line 3 rats with retinal degeneration 6-67 days after transplant surgery. The transplants were morphologically categorized as no transplant, detachment, rosettes, small laminated area and larger laminated area with both Fourier-domain OCT and histology. The efficacy of Fourier-domain OCT in screening retinal transplants was evaluated by comparing the categorization results with OCT and histology. Additionally, 4 rats were randomly selected for multiple OCT examinations (1, 5, 9, 14 and 21days post surgery) in order to determine the earliest image time of OCT examination since the transplanted tissue may need some time to show its tendency of growing. Finally, we demonstrated the efficacy of Fourier-domain OCT in screening retinal transplants in early stages and determined the earliest imaging time for OCT. Fourier-domain OCT makes itself valuable in saving resource spent on animals with unsuccessful transplants.

An Exploration of Social Media Use among Multiply Minoritized LGBTQ Youth

Science.gov (United States)

Lucero, Alfie Leanna

2013-01-01

This study responds to a need for research in a fast-growing and significant area of study, that of exploring, understanding, and documenting the numerous ways that multiply marginalized LGBTQ youth between the ages of 14 and 17 use social media. The primary research question examined whether social media provide safe spaces for multiply…

The Multiplier Effect: A Strategy for the Continuing Education of School Psychologists

Science.gov (United States)

Lesiak, Walter; And Others

1975-01-01

Twenty-two school psychologists participated in a year long institute designed to test the use of a multiplier effect in the continuing professional development of school psychologists in Michigan. Results indicated that 550 school psychologists attended two in-service meetings with generally favorable reactions. (Author)

Treatment of Multiply Controlled Problem Behavior with Procedural Variations of Differential Reinforcement

Science.gov (United States)

Neidert, Pamela L.; Iwata, Brian A.; Dozier, Claudia L.

2005-01-01

We describe the assessment and treatment of 2 children with autism spectrum disorder whose problem behaviors (self-injury, aggression, and disruption) were multiply controlled. Results of functional analyses indicated that the children's problem behaviors were maintained by both positive reinforcement (attention) and negative reinforcement (escape…

Coupled-Multiplier Accelerator Produces High-Power Electron Beams for Industrial Applications

International Nuclear Information System (INIS)

Hatridge, M.; McIntyre, P.; Roberson, S.; Sattarov, A.; Thomas, E.; Meitzler, Charles

2003-01-01

The coupled multiplier is a new approach to efficient generation of MeV d.c. power for accelerator applications. High voltage is produced by a series of modules, each of which consists of a high-power alternator, step-up transformer, and 3-phase multiplier circuit. The alternators are connected mechanically along a rotating shaft, and connected by insulating flexible couplers. This approach differs from all previous d.c. technologies in that power is delivered to the various stages of the system mechanically, rather than through capacitive or inductive electrical coupling. For this reason the capital cost depends linearly on required voltage and power, rather than quadratically as with conventional technologies. The CM technology enables multiple electron beams to be driven within a common supply and insulating housing. MeV electron beam is extremely effective in decomposing organic contaminants in water. A 1 MeV, 100 kW industrial accelerator using the CM technology has been built and is being installed for treatment of wastewater at a petrochemical plant

Fourier analysis in several complex variables

CERN Document Server

Ehrenpreis, Leon

2006-01-01

Suitable for advanced undergraduates and graduate students, this text develops comparison theorems to establish the fundamentals of Fourier analysis and to illustrate their applications to partial differential equations.The three-part treatment begins by establishing the quotient structure theorem or fundamental principle of Fourier analysis. Topics include the geometric structure of ideals and modules, quantitative estimates, and examples in which the theory can be applied. The second part focuses on applications to partial differential equations and covers the solution of homogeneous and inh

DCXE, Time-Dependent Xe Diffusion in Non-Multiplying Slab

International Nuclear Information System (INIS)

Horikami, K.; Kawasaki, S.

1969-01-01

1 - Nature of physical problem solved: Programme DCXE was designed for the analysis of the diffusion phenomena of xenon in non-multiplying media (slab geometry) and solves the Fick's second diffusion equation with boundary conditions. Initial distribution of xenon in the media at time 0 and 0 value of distribution at both ends of media at any positive time. 2 - Method of solution: Difference approximation is used to solve Fick's second diffusion equation. Strict stability condition is chosen between time and spatial intervals

DCXE, Time-Dependent Xe Diffusion in Non-Multiplying Slab

Energy Technology Data Exchange (ETDEWEB)

Horikami, K; Kawasaki, S [Japan Atomic Energy Research Institute, Tokai, Ibaraki (Japan)

1969-01-01

1 - Nature of physical problem solved: Programme DCXE was designed for the analysis of the diffusion phenomena of xenon in non-multiplying media (slab geometry) and solves the Fick's second diffusion equation with boundary conditions. Initial distribution of xenon in the media at time 0 and 0 value of distribution at both ends of media at any positive time. 2 - Method of solution: Difference approximation is used to solve Fick's second diffusion equation. Strict stability condition is chosen between time and spatial intervals.

Applied Fourier analysis from signal processing to medical imaging

CERN Document Server

Olson, Tim

2017-01-01

The first of its kind, this focused textbook serves as a self-contained resource for teaching from scratch the fundamental mathematics of Fourier analysis and illustrating some of its most current, interesting applications, including medical imaging and radar processing. Developed by the author from extensive classroom teaching experience, it provides a breadth of theory that allows students to appreciate the utility of the subject, but at as accessible a depth as possible. With myriad applications included, this book can be adapted to a one or two semester course in Fourier Analysis or serve as the basis for independent study. Applied Fourier Analysis assumes no prior knowledge of analysis from its readers, and begins by making the transition from linear algebra to functional analysis. It goes on to cover basic Fourier series and Fourier transforms before delving into applications in sampling and interpolation theory, digital communications, radar processing, medical i maging, and heat and wave equations. Fo...

Fourier convergence analysis applied to neutron diffusion Eigenvalue problem

International Nuclear Information System (INIS)

Lee, Hyun Chul; Noh, Jae Man; Joo, Hyung Kook

2004-01-01

Fourier error analysis has been a standard technique for the stability and convergence analysis of linear and nonlinear iterative methods. Though the methods can be applied to Eigenvalue problems too, all the Fourier convergence analyses have been performed only for fixed source problems and a Fourier convergence analysis for Eigenvalue problem has never been reported. Lee et al proposed new 2-D/1-D coupling methods and they showed that the new ones are unconditionally stable while one of the two existing ones is unstable at a small mesh size and that the new ones are better than the existing ones in terms of the convergence rate. In this paper the convergence of method A in reference 4 for the diffusion Eigenvalue problem was analyzed by the Fourier analysis. The Fourier convergence analysis presented in this paper is the first one applied to a neutronics eigenvalue problem to the best of our knowledge

Charge-transfer properties in the gas electron multiplier

International Nuclear Information System (INIS)

Han, Sanghyo; Kim, Yongkyun; Cho, Hyosung

2004-01-01

The charge transfer properties of a gas electron multiplier (GEM) were systematically investigated over a broad range of electric field configurations. The electron collection efficiency and the charge sharing were found to depend on the external fields, as well as on the GEM voltage. The electron collection efficiency increased with the collection field up to 90%, but was essentially independent of the drift field strength. A double conical GEM has a 10% gain increase with time due to surface charging by avalanche ions whereas this effect was eliminated with the cylindrical GEM. The positive-ion feedback is also estimated. (author)

Fourier duality as a quantization principle

International Nuclear Information System (INIS)

Aldrovandi, R.; Saeger, L.A.

1996-08-01

The Weyl-Wigner prescription for quantization on Euclidean phase spaces makes essential use of Fourier duality. The extension of this property to more general phase spaces requires the use of Kac algebras, which provide the necessary background for the implementation of Fourier duality on general locally groups. Kac algebras - and the duality they incorporate are consequently examined as candidates for a general quantization framework extending the usual formalism. Using as a test case the simplest non-trivial phase space, the half-plane, it is shown how the structures present in the complete-plane case must be modified. Traces, for example, must be replaced by their noncommutative generalizations - weights - and the correspondence embodied in the Weyl-Wigner formalism is no more complete. Provided the underlying algebraic structure is suitably adapted to each case, Fourier duality is shown to be indeed a very powerful guide to the quantization of general physical systems. (author). 30 refs

Methods of Fourier analysis and approximation theory

CERN Document Server

Tikhonov, Sergey

2016-01-01

Different facets of interplay between harmonic analysis and approximation theory are covered in this volume. The topics included are Fourier analysis, function spaces, optimization theory, partial differential equations, and their links to modern developments in the approximation theory. The articles of this collection were originated from two events. The first event took place during the 9th ISAAC Congress in Krakow, Poland, 5th-9th August 2013, at the section “Approximation Theory and Fourier Analysis”. The second event was the conference on Fourier Analysis and Approximation Theory in the Centre de Recerca Matemàtica (CRM), Barcelona, during 4th-8th November 2013, organized by the editors of this volume. All articles selected to be part of this collection were carefully reviewed.

Fourier path-integral Monte Carlo methods: Partial averaging

International Nuclear Information System (INIS)

Doll, J.D.; Coalson, R.D.; Freeman, D.L.

1985-01-01

Monte Carlo Fourier path-integral techniques are explored. It is shown that fluctuation renormalization techniques provide an effective means for treating the effects of high-order Fourier contributions. The resulting formalism is rapidly convergent, is computationally convenient, and has potentially useful variational aspects

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",…

Counting efficiency for liquid scintillator systems with a single multiplier phototube

International Nuclear Information System (INIS)

Grau Malonda, A.; Garcia-Torano, E.

1984-01-01

In this paper counting efficiency as a function of a free parameter (the figure of merit) has been computed. The results are applicable to liquid scintillator systems with a single multiplier phototube. Tables of counting efficiency for 62 pure beta emitters are given for figures of merit in the range 0.25 to 50. (Author) 16 refs

Fourier-Accelerated Nodal Solvers (FANS) for homogenization problems

Science.gov (United States)

Leuschner, Matthias; Fritzen, Felix

2017-11-01

Fourier-based homogenization schemes are useful to analyze heterogeneous microstructures represented by 2D or 3D image data. These iterative schemes involve discrete periodic convolutions with global ansatz functions (mostly fundamental solutions). The convolutions are efficiently computed using the fast Fourier transform. FANS operates on nodal variables on regular grids and converges to finite element solutions. Compared to established Fourier-based methods, the number of convolutions is reduced by FANS. Additionally, fast iterations are possible by assembling the stiffness matrix. Due to the related memory requirement, the method is best suited for medium-sized problems. A comparative study involving established Fourier-based homogenization schemes is conducted for a thermal benchmark problem with a closed-form solution. Detailed technical and algorithmic descriptions are given for all methods considered in the comparison. Furthermore, many numerical examples focusing on convergence properties for both thermal and mechanical problems, including also plasticity, are presented.

The impact of founder events on chromosomal variability in multiply mating species

DEFF Research Database (Denmark)

Pool, John E; Nielsen, Rasmus

2008-01-01

size reductions and recent bottlenecks leading to decreased X/A diversity ratios. Here we use theory and simulation to investigate a separate demographic effect-that of founder events involving multiply mated females-and find that it leads to much stronger reductions in X/A diversity ratios than...

Inverse mass matrix via the method of localized lagrange multipliers

Czech Academy of Sciences Publication Activity Database

González, José A.; Kolman, Radek; Cho, S.S.; Felippa, C.A.; Park, K.C.

2018-01-01

Roč. 113, č. 2 (2018), s. 277-295 ISSN 0029-5981 R&D Projects: GA MŠk(CZ) EF15_003/0000493; GA ČR GA17-22615S Institutional support: RVO:61388998 Keywords : explicit time integration * inverse mass matrix * localized Lagrange multipliers * partitioned analysis Subject RIV: BI - Acoustics OBOR OECD: Applied mechanics Impact factor: 2.162, year: 2016 https://onlinelibrary.wiley.com/doi/10.1002/nme.5613

Dispersion, Topological Scattering, and Self-Interference in Multiply Connected Robertson-Walker Cosmologies

CERN Document Server

Tomaschitz, R

1994-01-01

We investigate scattering effects in open Robertson-Walker cosmologies whose spacelike slices are multiply connected hyperbolic manifolds. We work out an example in which the 3-space is infinite and has the topology of a solid torus. The world-lines in these cosmologies are unstable, and classical probability densities evolving under the horospherical geodesic flow show dispersion, as do the densities of scalar wave packets. The rate of dispersion depends crucially on the expansion factor, and we calculate the time evolution of their widths. We find that the cosmic expansion can confine dispersion: The diameter of the domain of chaoticity in the 3-manifold provides the natural, time-dependent length unit in an infinite, multiply connected universe. In a toroidal 3-space manifold this diameter is just the length of the limit cycle. On this scale we find that the densities take a finite limit width in the late stage of the expansion. In the early stage classical densities and conformally coupled fields approach...

An overview of current developments in position-sensitive hybrid photon detectors and photo-multiplier tubes

CERN Document Server

Gys, Thierry

1999-01-01

Current developments in position-sensitive hybrid photon detectors and photo-multiplier tubes have stimulated increased interest from a variety of fields such as astronomy, biomedical imaging and high- energy physics. These devices are sensitive to single photons over a photon energy spectrum defined by the transmission of the optical entrance window and the photo-cathode type. Their spatial resolution ranges from a few millimeters for pad hybrid photon detectors and multi-anode photo-multiplier tubes down to a few tens of microns for pixel hybrid photon detectors and electron-bombarded charge-coupled devices. Basic technological and design aspects are assessed in this paper. (21 refs).

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

Dynamics of chemical reactions of multiply-charged cations: Information from beam scattering experiments

Czech Academy of Sciences Publication Activity Database

Herman, Zdeněk

2015-01-01

Roč. 378, FEB 2015 (2015), s. 113-126 ISSN 1387-3806 Institutional support: RVO:61388955 Keywords : Multiply-charged ions * Dynamics of chemical reactions * Beam scattering Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.183, year: 2015

Iterative wave-front reconstruction in the Fourier domain.

Science.gov (United States)

Bond, Charlotte Z; Correia, Carlos M; Sauvage, Jean-François; Neichel, Benoit; Fusco, Thierry

2017-05-15

The use of Fourier methods in wave-front reconstruction can significantly reduce the computation time for large telescopes with a high number of degrees of freedom. However, Fourier algorithms for discrete data require a rectangular data set which conform to specific boundary requirements, whereas wave-front sensor data is typically defined over a circular domain (the telescope pupil). Here we present an iterative Gerchberg routine modified for the purposes of discrete wave-front reconstruction which adapts the measurement data (wave-front sensor slopes) for Fourier analysis, fulfilling the requirements of the fast Fourier transform (FFT) and providing accurate reconstruction. The routine is used in the adaptation step only and can be coupled to any other Wiener-like or least-squares method. We compare simulations using this method with previous Fourier methods and show an increase in performance in terms of Strehl ratio and a reduction in noise propagation for a 40×40 SPHERE-like adaptive optics system. For closed loop operation with minimal iterations the Gerchberg method provides an improvement in Strehl, from 95.4% to 96.9% in K-band. This corresponds to ~ 40 nm improvement in rms, and avoids the high spatial frequency errors present in other methods, providing an increase in contrast towards the edge of the correctable band.

Compact Microwave Fourier Spectrum Analyzer

Science.gov (United States)

Savchenkov, Anatoliy; Matsko, Andrey; Strekalov, Dmitry

2009-01-01

A compact photonic microwave Fourier spectrum analyzer [a Fourier-transform microwave spectrometer, (FTMWS)] with no moving parts has been proposed for use in remote sensing of weak, natural microwave emissions from the surfaces and atmospheres of planets to enable remote analysis and determination of chemical composition and abundances of critical molecular constituents in space. The instrument is based on a Bessel beam (light modes with non-zero angular momenta) fiber-optic elements. It features low power consumption, low mass, and high resolution, without a need for any cryogenics, beyond what is achievable by the current state-of-the-art in space instruments. The instrument can also be used in a wide-band scatterometer mode in active radar systems.

Electron and X-ray emission in collisions of multiply charged ions and atoms

International Nuclear Information System (INIS)

Woerlee, P.H.

1979-01-01

The author presents experimental results of electron and X-ray emission following slow collisions of multiply charged ions and atoms. The aim of the investigation was to study the mechanisms which are responsible for the emission. (G.T.H.)

Experimental observation of Z-dependence of saturation depth of 0.662 MeV multiply scattered gamma rays

International Nuclear Information System (INIS)

Singh, Gurvinderjit; Singh, Manpreet; Singh, Bhajan; Sandhu, B.S.

2006-01-01

The gamma photons continue to soften in energy as the number of scatterings increases in the sample having finite dimensions both in depth and lateral dimensions. The number of multiply scattered photons increases with an increase in target thickness and saturates at a particular value of the target thickness known as saturation depth. The present experiment is undertaken to study the effect of atomic number of the target on saturation depth of 0.662 MeV incident gamma photons multiply scattered from targets of various thicknesses. The scattered photons are detected by an HPGe gamma detector placed at 90 o to the incident beam direction. We observe that with an increase in target thickness, the number of multiply scattered photons also increases and saturates at a particular value of the target thickness. The saturation depth decreases with increasing atomic number. The double Compton scattered peak is also observed in the experimental spectra

Science with multiply-charged ions at Brookhaven National Laboratory

International Nuclear Information System (INIS)

Jones, K.W.; Johnson, B.M.; Meron, M.; Thieberger, P.

1987-01-01

The production of multiply-charged heavy ions at Brookhaven National Laboratory and their use in different types of experiments are discussed. The main facilities that are used are the Double MP Tandem Van de Graaff and the National Synchrotron Light Source. The capabilities of a versatile Atomic Physics Facility based on a combination of the two facilities and a possible new heavy-ion storage ring are summarized. It is emphasized that the production of heavy ions and the relevant science necessitates very flexible and diverse apparatus

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)

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)

Fourier imaging of non-linear structure formation

Energy Technology Data Exchange (ETDEWEB)

Brandbyge, Jacob; Hannestad, Steen, E-mail: jacobb@phys.au.dk, E-mail: sth@phys.au.dk [Department of Physics and Astronomy, University of Aarhus, Ny Munkegade 120, DK-8000 Aarhus C (Denmark)

2017-04-01

We perform a Fourier space decomposition of the dynamics of non-linear cosmological structure formation in ΛCDM models. From N -body simulations involving only cold dark matter we calculate 3-dimensional non-linear density, velocity divergence and vorticity Fourier realizations, and use these to calculate the fully non-linear mode coupling integrals in the corresponding fluid equations. Our approach allows for a reconstruction of the amount of mode coupling between any two wavenumbers as a function of redshift. With our Fourier decomposition method we identify the transfer of power from larger to smaller scales, the stable clustering regime, the scale where vorticity becomes important, and the suppression of the non-linear divergence power spectrum as compared to linear theory. Our results can be used to improve and calibrate semi-analytical structure formation models.

Fourier imaging of non-linear structure formation

International Nuclear Information System (INIS)

Brandbyge, Jacob; Hannestad, Steen

2017-01-01

We perform a Fourier space decomposition of the dynamics of non-linear cosmological structure formation in ΛCDM models. From N -body simulations involving only cold dark matter we calculate 3-dimensional non-linear density, velocity divergence and vorticity Fourier realizations, and use these to calculate the fully non-linear mode coupling integrals in the corresponding fluid equations. Our approach allows for a reconstruction of the amount of mode coupling between any two wavenumbers as a function of redshift. With our Fourier decomposition method we identify the transfer of power from larger to smaller scales, the stable clustering regime, the scale where vorticity becomes important, and the suppression of the non-linear divergence power spectrum as compared to linear theory. Our results can be used to improve and calibrate semi-analytical structure formation models.

Fourier optical cryptosystem using complex spatial modulation

International Nuclear Information System (INIS)

Sarkadi, T; Koppa, P

2014-01-01

Our goal is to enhance the security level of a Fourier optical encryption system. Therefore we propose a Mach–Zehnder interferometer based encryption setup. The input data is organized in a binary array, and it is encoded in the two wave fronts propagated in the arms of the interferometer. Both input wave fronts are independently encrypted by Fourier systems, hence the proposed method has two encryption keys. During decryption, the encrypted wave fronts are propagated through the interferometer setup. The interference pattern of the output shows the reconstructed data in cases where the correct decryption Fourier keys are used. We propose a novel input image modulation method with a user defined phase parameter. We show that the security level of the proposed cryptosystem can be enhanced by an optimally chosen phase parameter. (paper)

Accelerated radial Fourier-velocity encoding using compressed sensing

Energy Technology Data Exchange (ETDEWEB)

Hilbert, Fabian; Han, Dietbert [Wuerzburg Univ. (Germany). Inst. of Radiology; Wech, Tobias; Koestler, Herbert [Wuerzburg Univ. (Germany). Inst. of Radiology; Wuerzburg Univ. (Germany). Comprehensive Heart Failure Center (CHFC)

2014-10-01

Purpose:Phase Contrast Magnetic Resonance Imaging (MRI) is a tool for non-invasive determination of flow velocities inside blood vessels. Because Phase Contrast MRI only measures a single mean velocity per voxel, it is only applicable to vessels significantly larger than the voxel size. In contrast, Fourier Velocity Encoding measures the entire velocity distribution inside a voxel, but requires a much longer acquisition time. For accurate diagnosis of stenosis in vessels on the scale of spatial resolution, it is important to know the velocity distribution of a voxel. Our aim was to determine velocity distributions with accelerated Fourier Velocity Encoding in an acquisition time required for a conventional Phase Contrast image. Materials and Methods:We imaged the femoral artery of healthy volunteers with ECG - triggered, radial CINE acquisition. Data acquisition was accelerated by undersampling, while missing data were reconstructed by Compressed Sensing. Velocity spectra of the vessel were evaluated by high resolution Phase Contrast images and compared to spectra from fully sampled and undersampled Fourier Velocity Encoding. By means of undersampling, it was possible to reduce the scan time for Fourier Velocity Encoding to the duration required for a conventional Phase Contrast image. Results:Acquisition time for a fully sampled data set with 12 different Velocity Encodings was 40 min. By applying a 12.6 - fold retrospective undersampling, a data set was generated equal to 3:10 min acquisition time, which is similar to a conventional Phase Contrast measurement. Velocity spectra from fully sampled and undersampled Fourier Velocity Encoded images are in good agreement and show the same maximum velocities as compared to velocity maps from Phase Contrast measurements. Conclusion: Compressed Sensing proved to reliably reconstruct Fourier Velocity Encoded data. Our results indicate that Fourier Velocity Encoding allows an accurate determination of the velocity

Accelerated radial Fourier-velocity encoding using compressed sensing

International Nuclear Information System (INIS)

Hilbert, Fabian; Han, Dietbert

2014-01-01

Purpose:Phase Contrast Magnetic Resonance Imaging (MRI) is a tool for non-invasive determination of flow velocities inside blood vessels. Because Phase Contrast MRI only measures a single mean velocity per voxel, it is only applicable to vessels significantly larger than the voxel size. In contrast, Fourier Velocity Encoding measures the entire velocity distribution inside a voxel, but requires a much longer acquisition time. For accurate diagnosis of stenosis in vessels on the scale of spatial resolution, it is important to know the velocity distribution of a voxel. Our aim was to determine velocity distributions with accelerated Fourier Velocity Encoding in an acquisition time required for a conventional Phase Contrast image. Materials and Methods:We imaged the femoral artery of healthy volunteers with ECG - triggered, radial CINE acquisition. Data acquisition was accelerated by undersampling, while missing data were reconstructed by Compressed Sensing. Velocity spectra of the vessel were evaluated by high resolution Phase Contrast images and compared to spectra from fully sampled and undersampled Fourier Velocity Encoding. By means of undersampling, it was possible to reduce the scan time for Fourier Velocity Encoding to the duration required for a conventional Phase Contrast image. Results:Acquisition time for a fully sampled data set with 12 different Velocity Encodings was 40 min. By applying a 12.6 - fold retrospective undersampling, a data set was generated equal to 3:10 min acquisition time, which is similar to a conventional Phase Contrast measurement. Velocity spectra from fully sampled and undersampled Fourier Velocity Encoded images are in good agreement and show the same maximum velocities as compared to velocity maps from Phase Contrast measurements. Conclusion: Compressed Sensing proved to reliably reconstruct Fourier Velocity Encoded data. Our results indicate that Fourier Velocity Encoding allows an accurate determination of the velocity

Accelerated radial Fourier-velocity encoding using compressed sensing.

Science.gov (United States)

Hilbert, Fabian; Wech, Tobias; Hahn, Dietbert; Köstler, Herbert

2014-09-01

Phase Contrast Magnetic Resonance Imaging (MRI) is a tool for non-invasive determination of flow velocities inside blood vessels. Because Phase Contrast MRI only measures a single mean velocity per voxel, it is only applicable to vessels significantly larger than the voxel size. In contrast, Fourier Velocity Encoding measures the entire velocity distribution inside a voxel, but requires a much longer acquisition time. For accurate diagnosis of stenosis in vessels on the scale of spatial resolution, it is important to know the velocity distribution of a voxel. Our aim was to determine velocity distributions with accelerated Fourier Velocity Encoding in an acquisition time required for a conventional Phase Contrast image. We imaged the femoral artery of healthy volunteers with ECG-triggered, radial CINE acquisition. Data acquisition was accelerated by undersampling, while missing data were reconstructed by Compressed Sensing. Velocity spectra of the vessel were evaluated by high resolution Phase Contrast images and compared to spectra from fully sampled and undersampled Fourier Velocity Encoding. By means of undersampling, it was possible to reduce the scan time for Fourier Velocity Encoding to the duration required for a conventional Phase Contrast image. Acquisition time for a fully sampled data set with 12 different Velocity Encodings was 40 min. By applying a 12.6-fold retrospective undersampling, a data set was generated equal to 3:10 min acquisition time, which is similar to a conventional Phase Contrast measurement. Velocity spectra from fully sampled and undersampled Fourier Velocity Encoded images are in good agreement and show the same maximum velocities as compared to velocity maps from Phase Contrast measurements. Compressed Sensing proved to reliably reconstruct Fourier Velocity Encoded data. Our results indicate that Fourier Velocity Encoding allows an accurate determination of the velocity distribution in vessels in the order of the voxel size. Thus

On the Cooley-Turkey Fast Fourier algorithm for arbitrary factors ...

African Journals Online (AJOL)

Atonuje and Okonta in [1] developed the Cooley-Turkey Fast Fourier transform algorithm and its application to the Fourier transform of discretely sampled data points N, expressed in terms of a power y of 2. In this paper, we extend the formalism of [1] Cookey-Turkey Fast Fourier transform algorithm. The method is developed ...

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.

Neutron multiplier alternative for fusion reactor blankets

International Nuclear Information System (INIS)

Taczanowski, S.

1980-01-01

A proposal is given to replace neutron multiplier needed to enable low lithium and tritium inventories simultaneously assuring sufficient production of tritium, by an efficient moderator ( 7 LiH or 7 LiD). The advantageous effect of the intensified neutron energy degradation is due to the 1/v character of the main tritium producing reaction. The slowing-down medium is designed to be the source of moderated neutrons for the surrounding Li ( 6 Li enriched) region where the most of tritium is to be produced. The surplus tritium production remains stored in the moderator zone. Some preliminary calculations illustrating the above concept were carried out and the neutron flux and tritium production distributions are presented. The indications regarding further studies are also suggested. (author)

Training Pragmatic Language Skills through Alternate Strategies with a Blind Multiply Handicapped Child.

Science.gov (United States)

Evans, C. J.; Johnson, C. J.

1988-01-01

A blind multiply handicapped preschooler was taught to respond appropriately to two adjacency pair types ("where question-answer" and "comment-acknowledgement"). The two alternative language acquisition strategies available to blind children were encouraged: echolalia to maintain communicative interactions and manual searching…

On Lagrange Multipliers in Work with Quality and Reliability Assurance

DEFF Research Database (Denmark)

Vidal, Rene Victor Valqui; Becker, P.

1986-01-01

In optimizing some property of a system, reliability say, a designer usually has to accept certain constraints regarding cost, completion time, volume, weight, etc. The solution of optimization problems with boundary constraints can be helped substantially by the use of Lagrange multipliers...... in the areas of sales promotion and teaching. These maps illuminate the logic structure of solution sequences. One such map is shown, illustrating the application of LMT in one of the examples....

Controlled G-Frames and Their G-Multipliers in Hilbert spaces

OpenAIRE

Rahimi, Asghar; Fereydooni, Abolhassan

2012-01-01

Multipliers have been recently introduced by P. Balazs as operators for Bessel sequences and frames in Hilbert spaces. These are operators that combine (frame-like) analysis, a multiplication with a fixed sequence (called the symbol) and synthesis. Weighted and controlled frames have been introduced to improve the numerical efficiency of iterative algorithms for inverting the frame operator Also g-frames are the most popular generalization of frames that include almost all of the frame extens...

Digital Predistortion of 75-110GHzW-Band Frequency Multiplier for Fiber Wireless Short Range Access Systems

DEFF Research Database (Denmark)

Zhao, Ying; Pang, Xiaodan; Deng, Lei

2011-01-01

We present a digital predistortion technique to effectively compensate high nonlinearity of a sextuple multiplier operating at 99.6GHz. An 18.9dB adjacent-channel power ratio (ACPR) improvement is guaranteed and a W-band fiber-wireless system is experimentally investigated.......We present a digital predistortion technique to effectively compensate high nonlinearity of a sextuple multiplier operating at 99.6GHz. An 18.9dB adjacent-channel power ratio (ACPR) improvement is guaranteed and a W-band fiber-wireless system is experimentally investigated....

Cross-gender Social Normative Effects for Violence in Middle School: Do Girls Carry a Social Multiplier Effect for At-risk Boys?

Science.gov (United States)

Pasch, Keryn E.; Brown, H. Shelton; Perry, Cheryl L.; Komro, Kelli A.

2014-01-01

A social multiplier effect is a social interaction in which the behavior of a person in a social network varies with the normative behavior of others in the network, also known as an endogenous interaction. Policies and intervention efforts can harness social multiplier effects because, in theory, interventions on a subset of individuals will have “spillover effects” on other individuals in the network. This study investigates potential social multiplier effects for violence in middle schools, and whether there is evidence for a social multiplier effect transmitted from girls to boys. Three years of longitudinal data (2003–2005) from Project Northland Chicago (PNC) were used to investigate this question, with a sample consisting of youth in Grades 6 through 8 in 61 Chicago Public Schools (N = 4233 at Grade 6, N = 3771 at Grade 7, and N = 3793 at Grade 8). The sample was 49.3% female, and primarily African American (41.9%) and Latino/a (28.7%), with smaller proportions of whites (12.9%), Asians (5.2%) and other ethnicities. Results from two sets of regression models estimating the effects of 20th (low), 50th (average), and 80th (high) percentile scores for girls and boys on levels of violence in each gender group revealed evidence for social multiplier effects. Specifically, boys and girls were both influenced by social multiplier effects within their own gender group, and boys were also affected by normative violence scores among girls, typically those of the best-behaved (20th percentile) girls. The finding that girls may have positive social influence on boys’ levels of violent behavior extends prior findings of beneficial social effects of girls on boys in the domains of education and risky driving. Further, this social normative effect presents a potential opportunity to improve school-based intervention efforts for reducing violence among youth by leveraging girls as carriers of a social multiplier effect for reduced violence in the middle school

Cross-gender social normative effects for violence in middle school: do girls carry a social multiplier effect for at-risk boys?

Science.gov (United States)

Yarnell, Lisa M; Pasch, Keryn E; Brown, H Shelton; Perry, Cheryl L; Komro, Kelli A

2014-09-01

A social multiplier effect is a social interaction in which the behavior of a person in a social network varies with the normative behavior of others in the network, also known as an endogenous interaction. Policies and intervention efforts can harness social multiplier effects because, in theory, interventions on a subset of individuals will have "spillover effects" on other individuals in the network. This study investigates potential social multiplier effects for violence in middle schools, and whether there is evidence for a social multiplier effect transmitted from girls to boys. Three years of longitudinal data (2003-2005) from Project Northland Chicago were used to investigate this question, with a sample consisting of youth in Grades 6 through 8 in 61 Chicago Public Schools (N = 4,233 at Grade 6, N = 3,771 at Grade 7, and N = 3,793 at Grade 8). The sample was 49.3% female, and primarily African American (41.9%) and Latino/a (28.7%), with smaller proportions of whites (12.9%), Asians (5.2%) and other ethnicities. Results from two sets of regression models estimating the effects of 20th (low), 50th (average), and 80th (high) percentile scores for girls and boys on levels of violence in each gender group revealed evidence for social multiplier effects. Specifically, boys and girls were both influenced by social multiplier effects within their own gender group, and boys were also affected by normative violence scores among girls, typically those of the best-behaved (20th percentile) girls. The finding that girls may have positive social influence on boys' levels of violent behavior extends prior findings of beneficial social effects of girls on boys in the domains of education and risky driving. Further, this social normative effect presents a potential opportunity to improve school-based intervention efforts for reducing violence among youth by leveraging girls as carriers of a social multiplier effect for reduced violence in the middle school environmental

Chromatographic analysis and purification of multiply tritium-labelled eicosanoids

International Nuclear Information System (INIS)

Shevchenko, V.P.; Nagaev, I.Yu.; Myasoedov, N.F.

1988-01-01

A comparative study of different chromatographic techniques (gas-liquid (GLC), thin-layer (TLC), liquid (LC), high-pressure liquid (HPLC) chromatography) is presented. They were applied to the analysis and preparative purification of tritium-labelled eicosanoids with a molar radioactivity of 1.8-8.8 TBq/mmol, obtained by selective hydrogenation and by chemical or enzymic methods. The possibility of analyzing reaction mixtures and isolating individual multiply labelled eicosanoids with a chemical and radiochemical purity of 95-98% was demonstrated. Special features of HPLC for high molar radioactivity eicosanoids are considered. (author) 9 refs.; 6 tabs

Experimental observation of energy dependence of saturation thickness of multiply scattered gamma photons

International Nuclear Information System (INIS)

Singh, Manpreet; Singh, Gurvinderjit; Singh, Bhajan; Sandhu, B.S.

2008-01-01

The gamma photons continue to soften in energy as the number of scatterings increases in the target having finite dimensions both in depth and lateral dimensions. The number of multiply scattered photons increases with an increase in target thickness, and saturates at a particular value of the target thickness known as saturation thickness (depth). The present measurements are carried out to study the energy dependence of saturation thickness of multiply scattered gamma photons from targets of various thicknesses. The scattered photons are detected by a properly shielded NaI(Tl) gamma ray detector placed at 90 deg. to the incident beam. We observe that the saturation thickness increases with increasing incident gamma photon energy. Monte Carlo calculations based upon the package developed by Bauer and Pattison [Compton scattering experiments at the HMI (1981), HMI-B 364, pp. 1-106] support the present experimental results

A unified Fourier theory for time-of-flight PET data.

Science.gov (United States)

Li, Yusheng; Matej, Samuel; Metzler, Scott D

2016-01-21

Fully 3D time-of-flight (TOF) PET scanners offer the potential of previously unachievable image quality in clinical PET imaging. TOF measurements add another degree of redundancy for cylindrical PET scanners and make photon-limited TOF-PET imaging more robust than non-TOF PET imaging. The data space for 3D TOF-PET data is five-dimensional with two degrees of redundancy. Previously, consistency equations were used to characterize the redundancy of TOF-PET data. In this paper, we first derive two Fourier consistency equations and Fourier-John equation for 3D TOF PET based on the generalized projection-slice theorem; the three partial differential equations (PDEs) are the dual of the sinogram consistency equations and John's equation. We then solve the three PDEs using the method of characteristics. The two degrees of entangled redundancy of the TOF-PET data can be explicitly elicited and exploited by the solutions of the PDEs along the characteristic curves, which gives a complete understanding of the rich structure of the 3D x-ray transform with TOF measurement. Fourier rebinning equations and other mapping equations among different types of PET data are special cases of the general solutions. We also obtain new Fourier rebinning and consistency equations (FORCEs) from other special cases of the general solutions, and thus we obtain a complete scheme to convert among different types of PET data: 3D TOF, 3D non-TOF, 2D TOF and 2D non-TOF data. The new FORCEs can be used as new Fourier-based rebinning algorithms for TOF-PET data reduction, inverse rebinnings for designing fast projectors, or consistency conditions for estimating missing data. Further, we give a geometric interpretation of the general solutions--the two families of characteristic curves can be obtained by respectively changing the azimuthal and co-polar angles of the biorthogonal coordinates in Fourier space. We conclude the unified Fourier theory by showing that the Fourier consistency equations are

Investigations of effect of target thickness and detector collimation on 662 keV multiply backscattered gamma photons

International Nuclear Information System (INIS)

Sabharwal, Arvind D.; Sandhu, B.S.; Singh, Bhajan

2009-01-01

The present studies aimed to investigate the effects of detector collimation and target thickness on multiply backscattered gamma photons. The numbers of multiply backscattered events, having energy the same as in singly scattered distribution, are found to be increasing with target thickness, and saturate for a particular thickness known as saturation thickness. The saturation thickness is not altered by the variation in the collimator opening. The number and energy albedos, characterizing the reflection probability of a material, are also evaluated. Monte Carlo calculations support the present experimental work.

Inference on the reliability of Weibull distribution with multiply Type-I censored data

International Nuclear Information System (INIS)

Jia, Xiang; Wang, Dong; Jiang, Ping; Guo, Bo

2016-01-01

In this paper, we focus on the reliability of Weibull distribution under multiply Type-I censoring, which is a general form of Type-I censoring. In multiply Type-I censoring in this study, all units in the life testing experiment are terminated at different times. Reliability estimation with the maximum likelihood estimate of Weibull parameters is conducted. With the delta method and Fisher information, we propose a confidence interval for reliability and compare it with the bias-corrected and accelerated bootstrap confidence interval. Furthermore, a scenario involving a few expert judgments of reliability is considered. A method is developed to generate extended estimations of reliability according to the original judgments and transform them to estimations of Weibull parameters. With Bayes theory and the Monte Carlo Markov Chain method, a posterior sample is obtained to compute the Bayes estimate and credible interval for reliability. Monte Carlo simulation demonstrates that the proposed confidence interval outperforms the bootstrap one. The Bayes estimate and credible interval for reliability are both satisfactory. Finally, a real example is analyzed to illustrate the application of the proposed methods. - Highlights: • We focus on reliability of Weibull distribution under multiply Type-I censoring. • The proposed confidence interval for the reliability is superior after comparison. • The Bayes estimates with a few expert judgements on reliability are satisfactory. • We specify the cases where the MLEs do not exist and present methods to remedy it. • The distribution of estimate of reliability should be used for accurate estimate.

Fourier-Based Diffraction Analysis of Live Caenorhabditis elegans.

Science.gov (United States)

Magnes, Jenny; Hastings, Harold M; Raley-Susman, Kathleen M; Alivisatos, Clara; Warner, Adam; Hulsey-Vincent, Miranda

2017-09-13

This manuscript describes how to classify nematodes using temporal far-field diffraction signatures. A single C. elegans is suspended in a water column inside an optical cuvette. A 632 nm continuous wave HeNe laser is directed through the cuvette using front surface mirrors. A significant distance of at least 20-30 cm traveled after the light passes through the cuvette ensures a useful far-field (Fraunhofer) diffraction pattern. The diffraction pattern changes in real time as the nematode swims within the laser beam. The photodiode is placed off-center in the diffraction pattern. The voltage signal from the photodiode is observed in real time and recorded using a digital oscilloscope. This process is repeated for 139 wild type and 108 "roller" C. elegans. Wild type worms exhibit a rapid oscillation pattern in solution. The "roller" worms have a mutation in a key component of the cuticle that interferes with smooth locomotion. Time intervals that are not free of saturation and inactivity are discarded. It is practical to divide each average by its maximum to compare relative intensities. The signal for each worm is Fourier transformed so that the frequency pattern for each worm emerges. The signal for each type of worm is averaged. The averaged Fourier spectra for the wild type and the "roller" C. elegans are distinctly different and reveal that the dynamic worm shapes of the two different worm strains can be distinguished using Fourier analysis. The Fourier spectra of each worm strain match an approximate model using two different binary worm shapes that correspond to locomotory moments. The envelope of the averaged frequency distribution for actual and modeled worms confirms the model matches the data. This method can serve as a baseline for Fourier analysis for many microscopic species, as every microorganism will have its unique Fourier spectrum.

Exploring Fourier Series and Gibbs Phenomenon Using Mathematica

Science.gov (United States)

Ghosh, Jonaki B.

2011-01-01

This article describes a laboratory module on Fourier series and Gibbs phenomenon which was undertaken by 32 Year 12 students. It shows how the use of CAS played the role of an "amplifier" by making higher level mathematical concepts accessible to students of year 12. Using Mathematica students were able to visualise Fourier series of…

Indirect mechanisms in electron-impact ionization of multiply charged ions

International Nuclear Information System (INIS)

Phaneuf, R.A.; Gregory, D.C.

1986-09-01

The important role of indirect-ionization mechanisms in electron-impact ionization of multiply charged ions has been emphasized by some recent experiments conducted with the ORNL-ECR multicharged ion source. Illustrative examples of investigations of the Mg-isoelectronic and Fe-isonuclear sequences are presented and compared with the results of detailed theoretical calculations. New experimental data is also presented concerning the role of resonance effects in the ionization of Li-like O 5+ and Na-like Fe 15+ ions

Timing characteristics of the VEhU-6 microchannel electron multipliers

International Nuclear Information System (INIS)

Bakhtizin, R.Z.; Yumaguzin, Yu.M.

1982-01-01

The VEhU-6 charnel electron multiplier timing characteristics are experimentally studied. Dependence of monoelectron pulse duration at the VEhU-6 output at different values of channel supply voltage is investigated. The VEhU-6 delay time is measured. Delay time increased from 10 to 30 ns with the increase of channel supply voltage from 2.8 to 3.2 kV (at approximately 10 5 pulse/s loading). Delay time increases with loading decrease

Neutralization of H-- in energetic collisions with multiply charged ions

International Nuclear Information System (INIS)

Melchert, F.; Benner, M.; Kruedener, S.; Schulze, R.; Meuser, S.; Huber, K.; Salzborn, E.; Uskov, D.B.; Presnyakov, L.P.

1995-01-01

Employing the crossed-beam technique, we have measured absolute cross sections for neutralization of H -- ions in collisions with multiply charged ions Ne q+ (q≤4) and Ar q+ , Xe q+ (q≤8) at center-of-mass energies ranging from 20 to 200 keV. . . It is found that th cross sections are independent of the target ion species. The data are in excellent agreement with quantum calculations. A universal scaling law for the neutralization cross section is given

Synthesis of highly faceted multiply twinned gold nanocrystals stabilized by polyoxometalates

International Nuclear Information System (INIS)

Yuan Junhua; Chen Yuanxian; Han Dongxue; Zhang Yuanjian; Shen Yanfei; Wang Zhijuan; Niu Li

2006-01-01

A novel and facile chemical synthesis of highly faceted multiply twinned gold nanocrystals is reported. The gold nanocrystals are hexagonal in transmission electron microscopy and icosahedral in scanning electron microscopy. Phosphotungstic acid (PTA), which was previously reduced, serves as a reductant and stabilizer for the synthesis of gold nanocrystals. The PTA-gold nanocomposites are quite stable in aqueous solutions, and electrochemically active towards the hydrogen evolution reaction

Limitations in THz Power Generation with Schottky Diode Varactor Frequency Multipliers

DEFF Research Database (Denmark)

Krozer, Viktor; Loata, G.; Grajal, J.

2002-01-01

, at increasing frequencies the power drops with f-3 instead of the f-2 predicted by theory. In this contribution we provide an overview of state-of-the-art results. A comparison with theoretically achievable multiplier performance reveals that the devices employed at higher frequencies are operating...... inefficiently and the design and fabrication capabilities have not reached the maturity encountered at lower THz frequencies....

Full inelastic cross section, effective stopping and ranges of fast multiply charged ions

International Nuclear Information System (INIS)

Alimov, R.A.; Arslanbekov, T.U.; Matveev, B.I.; Rakhmatov, A.S.

1994-01-01

Inelastic processes taking place in collision of fast multiply charged ions with atoms are considered on the base of mechanism of sudden momentum transfer. The simple estimations are proposed of full inelastic cross sections, effective stopping and ion ranges in gaseous medium. (author). 10 refs

International conference Fourier Analysis and Pseudo-Differential Operators

CERN Document Server

Turunen, Ville; Fourier Analysis : Pseudo-differential Operators, Time-Frequency Analysis and Partial Differential Equations

2014-01-01

This book is devoted to the broad field of Fourier analysis and its applications to several areas of mathematics, including problems in the theory of pseudo-differential operators, partial differential equations, and time-frequency analysis. This collection of 20 refereed articles is based on selected talks given at the international conference “Fourier Analysis and Pseudo-Differential Operators,” June 25–30, 2012, at Aalto University, Finland, and presents the latest advances in the field. The conference was a satellite meeting of the 6th European Congress of Mathematics, which took place in Krakow in July 2012; it was also the 6th meeting in the series “Fourier Analysis and Partial Differential Equations.”

An improved acoustic Fourier boundary element method formulation using fast Fourier transform integration

NARCIS (Netherlands)

Kuijpers, A.H.W.M.; Verbeek, G.; Verheij, J.W.

1997-01-01

Effective use of the Fourier series boundary element method (FBEM) for everyday applications is hindered by the significant numerical problems that have to be overcome for its implementation. In the FBEM formulation for acoustics, some integrals over the angle of revolution arise, which need to be

Colliding beam studies of electron detachement from H- by multiply-charged ions

International Nuclear Information System (INIS)

Melchert, F.; Benner, M.; Kruedener, S.; Schulze, R.; Meuser, S.; Pfaff, S.; Petri, S.; Huber, K.; Salzborn, E.; Presnyakov, L.P.; Uskov, D.B.

1993-01-01

Employing the crossed-beams technique, we have investigated electron-detachment processes from H - in collisions with multiply-charged noble gas ions A q+ . Absolute cross sections for single- and double-electron removal have been measured at center-of-mass energies from 50 keV to 200 keV and charge states q up to 8

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.

Infrared Fourier spectres of pectin obtained from pumpkin

International Nuclear Information System (INIS)

Usmanova, S.R.; Dzhonmurodov, A.S.; Nazirova, Kh.I.; Mukhidinov, Z.K.

2015-01-01

Present article is devoted to infrared Fourier spectres of pectin obtained from pumpkin. The analysis of pectin obtained from pumpkin was conducted by means of infrared spectrophotometer with Fourier transformation. The infrared spectroscopic study of pectin polysaccharide fraction of pectin matter, as well as pectin helium and micro helium obtained by means of fast extraction was conducted.

Charge transfer in gas electron multipliers

Energy Technology Data Exchange (ETDEWEB)

Ottnad, Jonathan; Ball, Markus; Ketzer, Bernhard; Ratza, Viktor; Razzaghi, Cina [HISKP, Bonn University, Nussallee 14-16, D-53115 Bonn (Germany)

2015-07-01

In order to efficiently employ a Time Projection Chamber (TPC) at interaction rates higher than ∝1 kHz, as foreseen e.g. in the ALICE experiment (CERN) and at CB-ELSA (Bonn), a continuous operation and readout mode is required. A necessary prerequisite is to minimize the space charge coming from the amplification system and to maintain an excellent spatial and energy resolution. Unfortunately these two goals can be in conflict to each other. Gas Electron Multipliers (GEM) are one candidate to fulfill these requirements. It is necessary to understand the processes within the amplification structure to find optimal operation conditions. To do so, we measure the charge transfer processes in and between GEM foils with different geometries and field configurations, and use an analytical model to describe the results. This model can then be used to predict and optimize the performance. The talk gives the present status of the measurements and describes the model.

A high linearity current mode multiplier/divider with a wide dynamic range

International Nuclear Information System (INIS)

Liao Pengfei; Luo Ping; Zhang Bo; Li Zhaoji

2012-01-01

A high linearity current mode multiplier/divider (CMM/D) with a wide dynamic range is presented. The proposed CMM/D is based on the voltage—current characteristic of the diode, thus wide dynamic range is achieved. In addition, high linearity is achieved because high accuracy current mirrors are adopted and the output current is insensitive to the temperature and device parameters of the fabrication process. Furthermore, no extra bias current for all input signals is required and thus power saving is realized. With proper selection of establishing the input terminal, the proposed circuit can perform as a multifunction circuit to be operated as a multiplier/divider, without changing its topology. The proposed circuit is implemented in a 0.25 μm BCD process and the chip area is 0.26 × 0.24 mm 2 . The simulation and measurement results show that the maximum static linearity error is ±1.8% and the total harmonic distortion is 0.4% while the input current ranges from 0 to 200 μA. (semiconductor integrated circuits)

Symplectic geometry and Fourier analysis

CERN Document Server

Wallach, Nolan R

2018-01-01

Suitable for graduate students in mathematics, this monograph covers differential and symplectic geometry, homogeneous symplectic manifolds, Fourier analysis, metaplectic representation, quantization, Kirillov theory. Includes Appendix on Quantum Mechanics by Robert Hermann. 1977 edition.

Sets of Fourier coefficients using numerical quadrature

International Nuclear Information System (INIS)

Lyness, J. N.

2001-01-01

One approach to the calculation of Fourier trigonometric coefficients f(r) of a given function f(x) is to apply the trapezoidal quadrature rule to the integral representation f(r)=(line i ntegral)(sub 0)(sup 1) f(x)e(sup -2(pi)irx)dx. Some of the difficulties in this approach are discussed. A possible way of overcoming many of these is by means of a subtraction function. Thus, one sets f(x)= h(sub p-1)(x)+ g(sub p)(x), where h(sub -1)(x) is an algebraic polynomial of degree p-1, specified in such a way that the Fourier series of g(sub p)(x) converges more rapidly than that of f(x). To obtain the Fourier coefficients of f(x), one uses an analytic expression for those of h(sub p-1)(x) and numerical quadrature to approximately those of g(sub p)(x)

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)

Effect of detector collimator and sample thickness on 0.662 MeV multiply Compton-scattered gamma rays

International Nuclear Information System (INIS)

Singh, Manpreet; Singh, Gurvinderjit; Sandhu, B.S.; Singh, Bhajan

2006-01-01

The simultaneous effect of detector collimator and sample thickness on 0.662 MeV multiply Compton-scattered gamma photons was studied experimentally. An intense collimated beam, obtained from 6-Ci 137 Cs source, is allowed to impinge on cylindrical aluminium samples of varying diameter and the scattered photons are detected by a 51 mmx51 mm NaI(Tl) scintillation detector placed at 90 o to the incident beam. The full energy peak corresponding to singly scattered events is reconstructed analytically. The thickness at which the multiply scattered events saturate is determined for different detector collimators. The parameters like signal-to-noise ratio and multiply scatter fraction (MSF) have also been deduced and support the work carried out by Shengli et al. [2000. EGS4 simulation of Compton scattering for nondestructive testing. KEK proceedings 200-20, Tsukuba, Japan, pp. 216-223] and Barnea et al. [1995. A study of multiple scattering background in Compton scatter imaging. NDT and E International 28, 155-162] based upon Monte Carlo calculations

Multiplied effect of heat and radiation in chemical stress relaxation

International Nuclear Information System (INIS)

Ito, Masayuki

1981-01-01

About the deterioration of rubber due to radiation, useful knowledge can be obtained by the measurement of chemical stress relaxation. As an example, the rubber coating of cables in a reactor containment vessel is estimated to be irradiated by weak radiation at the temperature between 60 and 90 deg C for about 40 years. In such case, it is desirable to establish the method of accelerated test of the deterioration. The author showed previously that the law of time-dose rate conversion holds in the case of radiation. In this study, the chemical stress relaxation to rubber was measured by the simultaneous application of heat and radiation, and it was found that there was the multiplied effect of heat and radiation in the stress relaxation speed. Therefore the factor of multiplication of heat and radiation was proposed to describe quantitatively the degree of the multiplied effect. The chloroprene rubber used was offered by Hitachi Cable Co., Ltd. The experimental method and the results are reported. The multiplication of heat and radiation is not caused by the direct cut of molecular chains by radiation, instead, it is based on the temperature dependence of various reaction rates at which the activated species reached the cut of molecular chains through complex reaction mechanism and the temperature dependence of the diffusion rate of oxygen in rubber. (Kako, I.)

Strength of the reversible, garbage-free 2 ^k ±1 multiplier

DEFF Research Database (Denmark)

Rotenberg, Eva; Cranch, James; Thomsen, Michael Kirkedal

2013-01-01

Recently, a reversible garbage-free 2 k ±1 constant-multiplier circuit was presented by Axelsen and Thomsen. This was the first construction of a garbage-free, reversible circuit for multiplication with non-trivial constants. At the time, the strength, that is, the range of constants obtainable...

Fourier Series Formalization in ACL2(r

Directory of Open Access Journals (Sweden)

Cuong K. Chau

2015-09-01

Full Text Available We formalize some basic properties of Fourier series in the logic of ACL2(r, which is a variant of ACL2 that supports reasoning about the real and complex numbers by way of non-standard analysis. More specifically, we extend a framework for formally evaluating definite integrals of real-valued, continuous functions using the Second Fundamental Theorem of Calculus. Our extended framework is also applied to functions containing free arguments. Using this framework, we are able to prove the orthogonality relationships between trigonometric functions, which are the essential properties in Fourier series analysis. The sum rule for definite integrals of indexed sums is also formalized by applying the extended framework along with the First Fundamental Theorem of Calculus and the sum rule for differentiation. The Fourier coefficient formulas of periodic functions are then formalized from the orthogonality relations and the sum rule for integration. Consequently, the uniqueness of Fourier sums is a straightforward corollary. We also present our formalization of the sum rule for definite integrals of infinite series in ACL2(r. Part of this task is to prove the Dini Uniform Convergence Theorem and the continuity of a limit function under certain conditions. A key technique in our proofs of these theorems is to apply the overspill principle from non-standard analysis.

Fast fourier algorithms in spectral computation and analysis of vibrating machines

International Nuclear Information System (INIS)

Farooq, U.; Hafeez, T.; Khan, M.Z.; Amir, M.

2001-01-01

In this work we have discussed Fourier and its history series, relationships among various Fourier mappings, Fourier coefficients, transforms, inverse transforms, integrals, analyses, discrete and fast algorithms for data processing and analysis of vibrating systems. The evaluation of magnitude of the source signal at transmission time, related coefficient matrix, intensity, and magnitude at the receiving end (stations). Matrix computation of Fourier transform has been explained, and applications are presented. The fast Fourier transforms, new computational scheme. have been tested with an example. The work also includes digital programs for obtaining the frequency contents of time function. It has been explained that how the fast Fourier algorithms (FFT) has decreased computational work by several order of magnitudes and split the spectrum of a signal into two (even and odd modes) at every successive step. That fast quantitative processing for discrete Fourier transforms' computations as well as signal splitting and combination provides an efficient. and reliable tool for spectral analyses. Fourier series decompose the given variable into a sum of oscillatory functions each having a specific frequency. These frequencies, with their corresponding amplitude and phase angles, constitute the frequency contents of the original time functions. These fast processing achievements, signals decomposition and combination may be carried out by the principle of superposition and convolution for, even, signals of different frequencies. Considerable information about a machine or a structure can be derived from variable speed and frequency tests. (author)

Effects of layer-multiplying and interface on the content of β-transcrystallization in PP

International Nuclear Information System (INIS)

Lei, Fan; Li, Jiang; Guo, Shaoyun

2015-01-01

The alternating multilayered polypropylene (PP layer)/β-nucleating agent filled-polypropylene (β-PP layer) were prepared through layer-multiplying extrusion combined with an assembly of layer-multiplying elements (LM Es). The content of β-crystal was firstly evaluated by differential scanning calorimetry (DSC), which indicated that the relative amount of the β-crystal increased from 38.67% to 81.22% with the increase of layer numbers from 2-layer to 128-layer. It was well consistent with the results of X-ray diffraction (XRD). The morphology observation of β-crystal by polarizing microscope (POM) revealed that the closely packed nuclei in the interface could induce numerous β-transcrystallization in pure PP layer due to the confinement effect. The non-isothermal crystallization kinetic analysis via Mozhishen’s methods manifested that the crystallization rate was greatly enhanced by the augment of the layered interface

Silicon Photo-Multiplier Radiation Hardness Tests with a White Neutron Beam

International Nuclear Information System (INIS)

Montanari, A.; Tosi, N.; Pietropaolo, A.; Andreotti, M.; Baldini, W.; Calabrese, R.; Cibinetto, G.; Luppi, E.; Cotta Ramusino, A.; Malaguti, R.; Santoro, V.; Tellarini, G.; Tomassetti, L.; De Donato, C.; Reali, E.

2013-06-01

We report radiation hardness tests performed, with a white neutron beam, at the Geel Electron Linear Accelerator in Belgium on silicon Photo-Multipliers. These are semiconductor photon detectors made of a square matrix of Geiger-Mode Avalanche photo-diodes on a silicon substrate. Several samples from different manufacturers have been irradiated integrating up to about 6.2 x 10 9 1-MeV-equivalent neutrons per cm 2 . (authors)

Enhanced fuel production in thorium fusion hybrid blankets utilizing uranium multipliers

International Nuclear Information System (INIS)

Pitulski, R.H.; Chapin, D.L.; Klevans, E.

1979-01-01

The multiplication of 14 MeV D-T fusion neutrons via (n,2n), (n,3n), and fission reactions by 238 U is well known and established. This study consistently evaluates the effectiveness of a depleted (tails) UO 2 multiplier on increasing the production of 233 U and tritium in a thorium/lithium fusion--fission hybrid blanket. Nuclear performance is evaluated as a function of exposure and zone thickness

Quantum-classical correspondence for the Fourier spectrum of a trajectory

International Nuclear Information System (INIS)

Heller, E.J.

1983-01-01

Using a displaced localized wavepacket (coherent state) as a quantum analog to a classical trajectory, we examine the Fourier spectrum of the expectation value of position Xsub(t)sup(Q), and compare it with the classical Fourier spectrum of position Xsub(t). In both the quasiperiodic and chaotic regimes, a strong classical-quantum correspondence exists in the Fourier spectrum. However, the quantum spectrum has certain interesting features not present in the classical case. (orig.)

Neutron fluctuation analysis in a subcritical multiplying system with a stochastically pulsed poisson source

International Nuclear Information System (INIS)

Kostic, Lj.

2003-01-01

The influence of the stochastically pulsed Poisson source to the statistical properties of the subcritical multiplying system is analyzed in the paper. It is shown a strong dependence on the pulse period and pulse width of the source (author)

Fourier descriptor classification of differential eddy current probe impedance plane trajectories

International Nuclear Information System (INIS)

Lord, W.; Satish, S.R.

1984-01-01

This chapter describes the use of a parametric model for representing the two-dimensional eddy current impedance plane trajectory. The main advantage of this approach is the ability to reconstruct the trajectory from the model coefficients. Fourier descriptors are used to facilitate defect classification. The Fourier descriptors are obtained by expanding the complex contour function in a Fourier series. Functions of Fourier coefficients which are invariant under transformation of the trajectory are derived and incorporated into a feature vector. Defect classification is obtained by using the K-Means algorithm to cluster the feature vectors. It is demonstrated that the Fourier descriptor approach represents a powerful tool which have several advantages over nonparametric approaches including its insensitivity to drift in the eddy current instrument as well as variations in the probe speed

Discrete Green’s function diakoptics for stable FDTD interaction between multiply-connected domains

NARCIS (Netherlands)

Hon, de B.P.; Arnold, J.M.; Graglia, R.D.

2007-01-01

We have developed FDTD boundary conditions based on discrete Green's function diakoptics for arbitrary multiply-connected 2D domains. The associated Z-domain boundary operator is symmetric, with an imaginary part that can be proved to be positive semi-definite on the upper half of the unit circle in

Statistics of electron multiplication in multiplier phototube: iterative method

International Nuclear Information System (INIS)

Grau Malonda, A.; Ortiz Sanchez, J.F.

1985-01-01

An iterative method is applied to study the variation of dynode response in the multiplier phototube. Three different situations are considered that correspond to the following ways of electronic incidence on the first dynode: incidence of exactly one electron, incidence of exactly r electrons and incidence of an average anti-r electrons. The responses are given for a number of steps between 1 and 5, and for values of the multiplication factor of 2.1, 2.5, 3 and 5. We study also the variance, the skewness and the excess of jurtosis for different multiplication factors. (author)

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

Ballooning modes or Fourier modes in a toroidal plasma?

International Nuclear Information System (INIS)

Connor, J.W.; Taylor, J.B.

1987-01-01

The relationship between two different descriptions of eigenmodes in a torus is investigated. In one the eigenmodes are similar to Fourier modes in a cylinder and are highly localized near a particular rational surface. In the other they are the so-called ballooning modes that extend over many rational surfaces. Using a model that represents both drift waves and resistive interchanges the transition from one of these structures to the other is investigated. In this simplified model the transition depends on a single parameter which embodies the competition between toroidal coupling of Fourier modes (which enhances ballooning) and variation in frequency of Fourier modes from one rational surface to another (which diminishes ballooning). As the coupling is increased each Fourier mode acquires a sideband on an adjacent rational surface and these sidebands then expand across the radius to form the extended mode described by the conventional ballooning mode approximation. This analysis shows that the ballooning approximation is appropriate for drift waves in a tokamak but not for resistive interchanges in a pinch. In the latter the conventional ballooning effect is negligible but they may nevertheless show a ballooning feature. This is localized near the same rational surface as the primary Fourier mode and so does not lead to a radially extended structure

Innovative design method of automobile profile based on Fourier descriptor

Science.gov (United States)

Gao, Shuyong; Fu, Chaoxing; Xia, Fan; Shen, Wei

2017-10-01

Aiming at the innovation of the contours of automobile side, this paper presents an innovative design method of vehicle side profile based on Fourier descriptor. The design flow of this design method is: pre-processing, coordinate extraction, standardization, discrete Fourier transform, simplified Fourier descriptor, exchange descriptor innovation, inverse Fourier transform to get the outline of innovative design. Innovative concepts of the innovative methods of gene exchange among species and the innovative methods of gene exchange among different species are presented, and the contours of the innovative design are obtained separately. A three-dimensional model of a car is obtained by referring to the profile curve which is obtained by exchanging xenogeneic genes. The feasibility of the method proposed in this paper is verified by various aspects.

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.

A unified Fourier theory for time-of-flight PET data

International Nuclear Information System (INIS)

Li, Yusheng; Matej, Samuel; Metzler, Scott D

2016-01-01

Fully 3D time-of-flight (TOF) PET scanners offer the potential of previously unachievable image quality in clinical PET imaging. TOF measurements add another degree of redundancy for cylindrical PET scanners and make photon-limited TOF-PET imaging more robust than non-TOF PET imaging. The data space for 3D TOF-PET data is five-dimensional with two degrees of redundancy. Previously, consistency equations were used to characterize the redundancy of TOF-PET data. In this paper, we first derive two Fourier consistency equations and Fourier–John equation for 3D TOF PET based on the generalized projection-slice theorem; the three partial differential equations (PDEs) are the dual of the sinogram consistency equations and John’s equation. We then solve the three PDEs using the method of characteristics. The two degrees of entangled redundancy of the TOF-PET data can be explicitly elicited and exploited by the solutions of the PDEs along the characteristic curves, which gives a complete understanding of the rich structure of the 3D x-ray transform with TOF measurement. Fourier rebinning equations and other mapping equations among different types of PET data are special cases of the general solutions. We also obtain new Fourier rebinning and consistency equations (FORCEs) from other special cases of the general solutions, and thus we obtain a complete scheme to convert among different types of PET data: 3D TOF, 3D non-TOF, 2D TOF and 2D non-TOF data. The new FORCEs can be used as new Fourier-based rebinning algorithms for TOF-PET data reduction, inverse rebinnings for designing fast projectors, or consistency conditions for estimating missing data. Further, we give a geometric interpretation of the general solutions—the two families of characteristic curves can be obtained by respectively changing the azimuthal and co-polar angles of the biorthogonal coordinates in Fourier space. We conclude the unified Fourier theory by showing that the Fourier consistency equations

Lacunary Fourier Series and a Qualitative Uncertainty Principle for ...

Indian Academy of Sciences (India)

We define lacunary Fourier series on a compact connected semisimple Lie group . If f ∈ L 1 ( G ) has lacunary Fourier series and vanishes on a non empty open subset of , then we prove that vanishes identically. This result can be viewed as a qualitative uncertainty principle.

Hybrid Fourier pseudospectral/discontinuous Galerkin time-domain method for wave propagation

Science.gov (United States)

Pagán Muñoz, Raúl; Hornikx, Maarten

2017-11-01

The Fourier Pseudospectral time-domain (Fourier PSTD) method was shown to be an efficient way of modelling acoustic propagation problems as described by the linearized Euler equations (LEE), but is limited to real-valued frequency independent boundary conditions and predominantly staircase-like boundary shapes. This paper presents a hybrid approach to solve the LEE, coupling Fourier PSTD with a nodal Discontinuous Galerkin (DG) method. DG exhibits almost no restrictions with respect to geometrical complexity or boundary conditions. The aim of this novel method is to allow the computation of complex geometries and to be a step towards the implementation of frequency dependent boundary conditions by using the benefits of DG at the boundaries, while keeping the efficient Fourier PSTD in the bulk of the domain. The hybridization approach is based on conformal meshes to avoid spatial interpolation of the DG solutions when transferring values from DG to Fourier PSTD, while the data transfer from Fourier PSTD to DG is done utilizing spectral interpolation of the Fourier PSTD solutions. The accuracy of the hybrid approach is presented for one- and two-dimensional acoustic problems and the main sources of error are investigated. It is concluded that the hybrid methodology does not introduce significant errors compared to the Fourier PSTD stand-alone solver. An example of a cylinder scattering problem is presented and accurate results have been obtained when using the proposed approach. Finally, no instabilities were found during long-time calculation using the current hybrid methodology on a two-dimensional domain.

Novel properties of the Fourier decomposition of the sinogram

International Nuclear Information System (INIS)

Edholm, P.R.; Lewitt, R.M.; Lindholm, B.

1986-01-01

The double Fourier decomposition of the sinogram is obtained by first taking the Fourier transform of each parallel-ray projection and then calculating the coefficients of a Fourier series with respect to angle for each frequency component of the transformed projections. The values of these coefficients may be plotted on a two-dimensional map whose coordinates are spatial frequency ω (continuous) and angular harmonic number n (discrete). For absolute value of ω large, the Fourier coefficients on the line n=kω of slope k through the origin of the coefficient space are found to depend strongly on the contributions to the projection data that, for each view, come from a certain distance to the detector plane, where the distance is a linear function of k. The values of these coefficients depend only weakly on contributions from other distances from the detector. The theoretical basis of this property is presented in this paper and a potential application to emission computerized tomography is discussed

Quadrature formulas for Fourier coefficients

KAUST Repository

Bojanov, Borislav; Petrova, Guergana

2009-01-01

We consider quadrature formulas of high degree of precision for the computation of the Fourier coefficients in expansions of functions with respect to a system of orthogonal polynomials. In particular, we show the uniqueness of a multiple node

Comparative analysis of imaging configurations and objectives for Fourier microscopy.

Science.gov (United States)

Kurvits, Jonathan A; Jiang, Mingming; Zia, Rashid

2015-11-01

Fourier microscopy is becoming an increasingly important tool for the analysis of optical nanostructures and quantum emitters. However, achieving quantitative Fourier space measurements requires a thorough understanding of the impact of aberrations introduced by optical microscopes that have been optimized for conventional real-space imaging. Here we present a detailed framework for analyzing the performance of microscope objectives for several common Fourier imaging configurations. To this end, we model objectives from Nikon, Olympus, and Zeiss using parameters that were inferred from patent literature and confirmed, where possible, by physical disassembly. We then examine the aberrations most relevant to Fourier microscopy, including the alignment tolerances of apodization factors for different objective classes, the effect of magnification on the modulation transfer function, and vignetting-induced reductions of the effective numerical aperture for wide-field measurements. Based on this analysis, we identify an optimal objective class and imaging configuration for Fourier microscopy. In addition, the Zemax files for the objectives and setups used in this analysis have been made publicly available as a resource for future studies.

Quantitative heart scintigraphy using Fourier analysis of unformated list mode data

International Nuclear Information System (INIS)

Knopp, R.; Schmidt, H.; Reichmann, K.; Biersack, H.J.; Winkler, C.

1981-01-01

Fourier transformation in radioventriculography is used for smoothing of the left ventricular volume curves as well as for the evaluating of regional wall motions by means of amplitude and phase imaging. Our new method is based on Fourier transformation from unformatted list mode data, pixel by pixel. Determination of the Fourier coefficients of 4 harmonic waves as a maximum is performed and frame sequences are generated by Fourier resynthesis. As main advantages of the method can be regarded a) considerable improvement of the image quality and b) substantial reduction of time needed for data acquisition. (orig.) [de

From Fourier analysis to wavelets

CERN Document Server

Gomes, Jonas

2015-01-01

This text introduces the basic concepts of function spaces and operators, both from the continuous and discrete viewpoints.  Fourier and Window Fourier Transforms are introduced and used as a guide to arrive at the concept of Wavelet transform.  The fundamental aspects of multiresolution representation, and its importance to function discretization and to the construction of wavelets is also discussed. Emphasis is given on ideas and intuition, avoiding the heavy computations which are usually involved in the study of wavelets.  Readers should have a basic knowledge of linear algebra, calculus, and some familiarity with complex analysis.  Basic knowledge of signal and image processing is desirable. This text originated from a set of notes in Portuguese that the authors wrote for a wavelet course on the Brazilian Mathematical Colloquium in 1997 at IMPA, Rio de Janeiro.

The correspondence between stochastic mechanics and quantum mechanics on multiply connected configuration spaces

International Nuclear Information System (INIS)

Carlen, E.A.; Loffredo, M.I.

1989-01-01

We show how to obtain a complete correspondence between stochastic and quantum mechanics on multiply connected spaces. We do this by introducing a stochastic mechanical analog of the hydrodynamical circulation, relating it to the topological properties of the configuration space, and using it to constrain the stochastic mechanical variational principles. (orig.)

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

Some applications of Fourier's great discovery for beginners

International Nuclear Information System (INIS)

Kraftmakher, Yaakov

2012-01-01

Nearly two centuries ago, Fourier discovered that any periodic function of period T can be presented as a sum of sine waveforms of frequencies equal to an integer times the fundamental frequency ω = 2π/T (Fourier's series). It is impossible to overestimate the importance of Fourier's discovery, and all physics or engineering students should be familiar with this subject. A suitable device for demonstrating spectra of electrical signals is a digital storage oscilloscope. Spectra of various waveforms and of AM and FM signals are demonstrated, as well as AM signals from a broadcasting station. Changes in the signals filtered by frequency-selective circuits are seen by comparing the spectra of the input and output voltages. All the experiments are suitable for undergraduate laboratories and usable as classroom demonstrations. (paper)

Novel hybrid optical correlator: theory and optical simulation.

Science.gov (United States)

Casasent, D; Herold, R L

1975-02-01

The inverse transform of the product of two Fourier transform holograms is analyzed and shown to contain the correlation of the two images from which the holograms were formed. The theory, analysis, and initial experimental demonstration of the feasibility of a novel correlation scheme using this multiplied Fourier transform hologram system are presented.

Outer-shell transitions in collisions between multiply charged ions and atoms

International Nuclear Information System (INIS)

Bloemen, E.W.P.

1980-01-01

The study of collisions between multiply charged ions and atoms (molecules) is of importance in different areas of research. Usually, the most important process is capture of an electron from the target atom into the projectile ion. In most cases the electron goes to an excited state of the projectile ion. These electron capture processes are studied. The author also studied direct excitation of the target atom and of the projectile ion. (Auth.)

Ionizing device comprising a microchannel electron multiplier with secondary electron emission

International Nuclear Information System (INIS)

Chalmeton, Vincent.

1974-01-01

The present invention relates to a ionizing device comprising a microchannel electron multiplier involving secondary electron emission as a means of ionization. A system of electrodes is used to accelerate said electrons, ionize the gas and extract the ions from thus created plasma. Said ionizer is suitable for bombarding the target in neutron sources (target of the type of nickel molybdenum coated with tritiated titanium or with a tritium deuterium mixture) [fr

Water temperature forecasting and estimation using fourier series and communication theory techniques

International Nuclear Information System (INIS)

Long, L.L.

1976-01-01

Fourier series and statistical communication theory techniques are utilized in the estimation of river water temperature increases caused by external thermal inputs. An example estimate assuming a constant thermal input is demonstrated. A regression fit of the Fourier series approximation of temperature is then used to forecast daily average water temperatures. Also, a 60-day prediction of daily average water temperature is made with the aid of the Fourier regression fit by using significant Fourier components

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

Residual Stress Studies Using the Cairo Fourier Diffractometer Facility

International Nuclear Information System (INIS)

Maayouf, R.M.A.; El-Shaer, Y.H.

2002-01-01

The present paper deals with residual stress studies using the Cairo Fourier diffractometer facility CFDF. The CFDF is a reverse - time of -flight (RTOF) diffractometer; applies a Fourier chopper. The measurements were performed for copper samples in order to study the residual stress after welding. The maximum modulation of the Fourier chopper during the measurements was 136 khz; leading to a time resolution half-width of about 7 μ s. It has been found from the present measurements that, the resulting diffraction spectra could be successfully used for studying the residual stress; in the wavelength range between 0.7-2.9 A degree at ∼ 0.45 % relative resolution

Fast Discrete Fourier Transform Computations Using the Reduced Adder Graph Technique

Directory of Open Access Journals (Sweden)

Andrew G. Dempster

2007-01-01

Full Text Available It has recently been shown that the n-dimensional reduced adder graph (RAG-n technique is beneficial for many DSP applications such as for FIR and IIR filters, where multipliers can be grouped in multiplier blocks. This paper highlights the importance of DFT and FFT as DSP objects and also explores how the RAG-n technique can be applied to these algorithms. This RAG-n DFT will be shown to be of low complexity and possess an attractively regular VLSI data flow when implemented with the Rader DFT algorithm or the Bluestein chirp-z algorithm. ASIC synthesis data are provided and demonstrate the low complexity and high speed of the design when compared to other alternatives.

Fast Discrete Fourier Transform Computations Using the Reduced Adder Graph Technique

Directory of Open Access Journals (Sweden)

Dempster Andrew G

2007-01-01

Full Text Available It has recently been shown that the -dimensional reduced adder graph (RAG- technique is beneficial for many DSP applications such as for FIR and IIR filters, where multipliers can be grouped in multiplier blocks. This paper highlights the importance of DFT and FFT as DSP objects and also explores how the RAG- technique can be applied to these algorithms. This RAG- DFT will be shown to be of low complexity and possess an attractively regular VLSI data flow when implemented with the Rader DFT algorithm or the Bluestein chirp- algorithm. ASIC synthesis data are provided and demonstrate the low complexity and high speed of the design when compared to other alternatives.

Bilaterally symmetric Fourier approximations of the skull outlines of ...

Indian Academy of Sciences (India)

Present work illustrates a scheme of quantitative description of the shape of the skull outlines of temnospondyl amphibians using bilaterally symmetric closed Fourier curves. Some special points have been identified on the Fourier fits of the skull outlines, which are the local maxima, or minima of the distances from the ...

Fourier rebinning and consistency equations for time-of-flight PET planograms.

Science.gov (United States)

Li, Yusheng; Defrise, Michel; Matej, Samuel; Metzler, Scott D

2016-01-01

Due to the unique geometry, dual-panel PET scanners have many advantages in dedicated breast imaging and on-board imaging applications since the compact scanners can be combined with other imaging and treatment modalities. The major challenges of dual-panel PET imaging are the limited-angle problem and data truncation, which can cause artifacts due to incomplete data sampling. The time-of-flight (TOF) information can be a promising solution to reduce these artifacts. The TOF planogram is the native data format for dual-panel TOF PET scanners, and the non-TOF planogram is the 3D extension of linogram. The TOF planograms is five-dimensional while the objects are three-dimensional, and there are two degrees of redundancy. In this paper, we derive consistency equations and Fourier-based rebinning algorithms to provide a complete understanding of the rich structure of the fully 3D TOF planograms. We first derive two consistency equations and John's equation for 3D TOF planograms. By taking the Fourier transforms, we obtain two Fourier consistency equations and the Fourier-John equation, which are the duals of the consistency equations and John's equation, respectively. We then solve the Fourier consistency equations and Fourier-John equation using the method of characteristics. The two degrees of entangled redundancy of the 3D TOF data can be explicitly elicited and exploited by the solutions along the characteristic curves. As the special cases of the general solutions, we obtain Fourier rebinning and consistency equations (FORCEs), and thus we obtain a complete scheme to convert among different types of PET planograms: 3D TOF, 3D non-TOF, 2D TOF and 2D non-TOF planograms. The FORCEs can be used as Fourier-based rebinning algorithms for TOF-PET data reduction, inverse rebinnings for designing fast projectors, or consistency conditions for estimating missing data. As a byproduct, we show the two consistency equations are necessary and sufficient for 3D TOF planograms

Research on nonlinearity effect of secondary electron multiplier

International Nuclear Information System (INIS)

Wei Xingjian; Liao Junsheng; Deng Dachao; Yu Chunrong; Yuan Li

2007-01-01

The nonlinearity of secondary electron multiplier (SEM) of a thermal ionization mass spectrometer has been researched by using UTB-500 uranium isotope reference material and multi-collecting technique. The results show that the nonlinearity effect of SEM exists in the whole ion counting range, and there is an extreme point of the nonlinearity when the ion counting rate is about 20000 cps. The deviation between measured value of the extreme point and the reference value of the reference sample can be up to 3%, and the nonlinearity obeys logarithm linearity law on both sides of extreme point. A kind of mathematics model of nonlinearity calibration has been put forward. Using this model, the nonlinearity of SEM of TIMS can be calibrated. (authors)

Transformada fraccional de Fourier aplicado a sistemas ópticos coherentes

OpenAIRE

Jiménez Ruiz, Carlos; Castillo Pérez, Jaime; Salinas de Romero, Susana

2010-01-01

En 1980 Namias presentó la Transformada de Fourier de orden fraccional como una generalización de la bien conocida Transformada de Fourier, estableciendo el carácter matemático de la misma junto con un conjunto de teoremas y propiedades. Inicialmente la utilizó para resolver problemas con el oscilador armónico mecánico cuántico. Recientemente en el área de la óptica de Fourier se ha extendido con nuevas contribuciones relativas a transformadas no convencionales denominadas transformadas Fracc...

Multiplier ideal sheaves and analytic methods in algebraic geometry

International Nuclear Information System (INIS)

Demailly, J.-P.

2001-01-01

Our main purpose here is to describe a few analytic tools which are useful to study questions such as linear series and vanishing theorems for algebraic vector bundles. One of the early successes of analytic methods in this context is Kodaira's use of the Bochner technique in relation with the theory of harmonic forms, during the decade 1950-60.The idea is to represent cohomology classes by harmonic forms and to prove vanishing theorems by means of suitable a priori curvature estimates. We pursue the study of L2 estimates, in relation with the Nullstellenstatz and with the extension problem. We show how subadditivity can be used to derive an approximation theorem for (almost) plurisubharmonic functions: any such function can be approximated by a sequence of (almost) plurisubharmonic functions which are smooth outside an analytic set, and which define the same multiplier ideal sheaves. From this, we derive a generalized version of the hard Lefschetz theorem for cohomology with values in a pseudo-effective line bundle; namely, the Lefschetz map is surjective when the cohomology groups are twisted by the relevant multiplier ideal sheaves. These notes are essentially written with the idea of serving as an analytic tool- box for algebraic geometers. Although efficient algebraic techniques exist, our feeling is that the analytic techniques are very flexible and offer a large variety of guidelines for more algebraic questions (including applications to number theory which are not discussed here). We made a special effort to use as little prerequisites and to be as self-contained as possible; hence the rather long preliminary sections dealing with basic facts of complex differential geometry

Multiplier ideal sheaves and analytic methods in algebraic geometry

Energy Technology Data Exchange (ETDEWEB)

Demailly, J -P [Universite de Grenoble I, Institut Fourier, Saint-Martin d' Heres (France)

2001-12-15

Our main purpose here is to describe a few analytic tools which are useful to study questions such as linear series and vanishing theorems for algebraic vector bundles. One of the early successes of analytic methods in this context is Kodaira's use of the Bochner technique in relation with the theory of harmonic forms, during the decade 1950-60.The idea is to represent cohomology classes by harmonic forms and to prove vanishing theorems by means of suitable a priori curvature estimates. We pursue the study of L2 estimates, in relation with the Nullstellenstatz and with the extension problem. We show how subadditivity can be used to derive an approximation theorem for (almost) plurisubharmonic functions: any such function can be approximated by a sequence of (almost) plurisubharmonic functions which are smooth outside an analytic set, and which define the same multiplier ideal sheaves. From this, we derive a generalized version of the hard Lefschetz theorem for cohomology with values in a pseudo-effective line bundle; namely, the Lefschetz map is surjective when the cohomology groups are twisted by the relevant multiplier ideal sheaves. These notes are essentially written with the idea of serving as an analytic tool- box for algebraic geometers. Although efficient algebraic techniques exist, our feeling is that the analytic techniques are very flexible and offer a large variety of guidelines for more algebraic questions (including applications to number theory which are not discussed here). We made a special effort to use as little prerequisites and to be as self-contained as possible; hence the rather long preliminary sections dealing with basic facts of complex differential geometry.

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

Wavelength modulation spectroscopy--digital detection of gas absorption harmonics based on Fourier analysis.

Science.gov (United States)

Mei, Liang; Svanberg, Sune

2015-03-20

This work presents a detailed study of the theoretical aspects of the Fourier analysis method, which has been utilized for gas absorption harmonic detection in wavelength modulation spectroscopy (WMS). The lock-in detection of the harmonic signal is accomplished by studying the phase term of the inverse Fourier transform of the Fourier spectrum that corresponds to the harmonic signal. The mathematics and the corresponding simulation results are given for each procedure when applying the Fourier analysis method. The present work provides a detailed view of the WMS technique when applying the Fourier analysis method.

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.

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

Practical model for the calculation of multiply scattered lidar returns

International Nuclear Information System (INIS)

Eloranta, E.W.

1998-01-01

An equation to predict the intensity of the multiply scattered lidar return is presented. Both the scattering cross section and the scattering phase function can be specified as a function of range. This equation applies when the cloud particles are larger than the lidar wavelength. This approximation considers photon trajectories with multiple small-angle forward-scattering events and one large-angle scattering that directs the photon back toward the receiver. Comparisons with Monte Carlo simulations, exact double-scatter calculations, and lidar data demonstrate that this model provides accurate results. copyright 1998 Optical Society of America

233U breeding and neutron multiplying blankets for fusion reactors

International Nuclear Information System (INIS)

Cook, A.G.; Maniscalco, J.A.

1975-01-01

In this work, along with a previous paper three possible uses of 14-MeV deuterium--tritium fusion neutrons are investigated: energy production, neutron multiplication, and fissile-fuel breeding. The results presented include neutronic studies of fissioning and nonfissioning thorium systems, tritium breeding systems, various fuel options (UO 2 , UC, UC 2 , etc.), and uranium as well as refractory metal first-wall neutron-multiplying regions. A brief energy balance and an estimate of potential revenues for fusion devices are given to help illustrate the potentials of these designs

Optimizing strassen matrix multiply on GPUs

KAUST Repository

ul Hasan Khan, Ayaz; Al-Mouhamed, Mayez; Fatayer, Allam

2015-01-01

© 2015 IEEE. Many core systems are basically designed for applications having large data parallelism. Strassen Matrix Multiply (MM) can be formulated as a depth first (DFS) traversal of a recursion tree where all cores work in parallel on computing each of the NxN sub-matrices that reduces storage at the detriment of large data motion to gather and aggregate the results. We propose Strassen and Winograd algorithms (S-MM and W-MM) based on three optimizations: a set of basic algebra functions to reduce overhead, invoking efficient library (CUBLAS 5.5), and parameter-tuning of parametric kernel to improve resource occupancy. On GPUs, W-MM and S-MM with one recursion level outperform CUBLAS 5.5 Library with up to twice as faster for large arrays satisfying N>=2048 and N>=3072, respectively. Compared to NVIDIA SDK library, S-MM and W-MM achieved a speedup between 20x to 80x for the above arrays. The proposed approach can be used to enhance the performance of CUBLAS and MKL libraries.

Optimizing strassen matrix multiply on GPUs

KAUST Repository

ul Hasan Khan, Ayaz

2015-06-01

© 2015 IEEE. Many core systems are basically designed for applications having large data parallelism. Strassen Matrix Multiply (MM) can be formulated as a depth first (DFS) traversal of a recursion tree where all cores work in parallel on computing each of the NxN sub-matrices that reduces storage at the detriment of large data motion to gather and aggregate the results. We propose Strassen and Winograd algorithms (S-MM and W-MM) based on three optimizations: a set of basic algebra functions to reduce overhead, invoking efficient library (CUBLAS 5.5), and parameter-tuning of parametric kernel to improve resource occupancy. On GPUs, W-MM and S-MM with one recursion level outperform CUBLAS 5.5 Library with up to twice as faster for large arrays satisfying N>=2048 and N>=3072, respectively. Compared to NVIDIA SDK library, S-MM and W-MM achieved a speedup between 20x to 80x for the above arrays. The proposed approach can be used to enhance the performance of CUBLAS and MKL libraries.

Analytical theory of frequency-multiplying gyro-traveling-wave-tubes

International Nuclear Information System (INIS)

Nusinovich, G.S.; Chen, W.; Granatstein, V.L.

2001-01-01

The theory is developed which describes analytically the gain and bandwidth in frequency-multiplying gyro-traveling-wave-tubes. In this theory the input waveguide is considered in the small-signal approximation. Then, in the drift region separating the input and output waveguides, the electron ballistic bunching evolves which causes the appearance in the electron current density of the harmonics of the signal frequency. The excitation of the output waveguide by one of these harmonics is considered in a specified current approximation. This makes the analytical study of a large-signal operation possible. The theory is illustrated by using it to analyze the performance of an existing experimental tube

Monte Carlo technique for local perturbations in multiplying systems

International Nuclear Information System (INIS)

Bernnat, W.

1974-01-01

The use of the Monte Carlo method for the calculation of reactivity perturbations in multiplying systems due to changes in geometry or composition requires a correlated sampling technique to make such calculations economical or in the case of very small perturbations even feasible. The technique discussed here is suitable for local perturbations. Very small perturbation regions will be treated by an adjoint mode. The perturbation of the source distribution due to the changed system and its reaction on the reactivity worth or other values of interest is taken into account by a fission matrix method. The formulation of the method and its application are discussed. 10 references. (U.S.)

Hardware matrix multiplier/accumulator for lattice gauge theory calculations

International Nuclear Information System (INIS)

Christ, N.H.; Terrano, A.E.

1984-01-01

The design and operating characteristics of a special-purpose matrix multiplier/accumulator are described. The device is connected through a standard interface to a host PDP11 computer. It provides a set of high-speed, matrix-oriented instructions which can be called from a program running on the host. The resulting operations accelerate the complex matrix arithmetic required for a class of Monte Carlo calculations currently of interest in high energy particle physics. A working version of the device is presently being used to carry out a pure SU(3) lattice gauge theory calculation using a PDP11/23 with a performance twice that obtainable on a VAX11/780. (orig.)

Charge-exchange collisions of multiply charged ions with atoms

International Nuclear Information System (INIS)

Grozdanov, T.P.; Janev, R.K.

1978-01-01

The problem of electron transfer between neutral atoms and multiply charged ions is considered at low and medium energies. It is assumed that a large number of final states are available for the electron transition so that the electron-capture process is treated as a tunnel effect caused by the strong attractive Coulomb field of the multicharged ions. The electron transition probability is obtained in a closed form using the modified-comparison-equation method to solve the Schroedinger equation. An approximately linear dependence of the one-electron transfer cross section on the charge of multicharged ion is found. Cross-section calculations of a number of charge-exchange reactions are performed

Implementation of neutron activation analysis in the neutron multiplier CS-ISCTN (first part)

International Nuclear Information System (INIS)

Contreras, R.; Ixquiac, M.; Hernandez, O.; Herrera, E.F.; Diaz, O.; Lopez, R.; Alvarez, I.; Manso, M.V.; Padron, G.; D Alessandro, K.

1997-01-01

The detection limit of 32 elements are determined after experimental evaluation of the neutron flux components in the irradiation position of the neutron multiplier CS-ISCTN. The control of the thermal flux was carry up, comparing the experimental results obtained through three convention used determination of the reaction rate, with the theoretical obtained before

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.

Almost everywhere convergence over cubes of multiple trigonometric Fourier series

International Nuclear Information System (INIS)

Antonov, N Yu

2004-01-01

Under certain conditions on a function φ:[0,+∞)→[0,+∞) we prove a theorem asserting that the convergence almost everywhere of trigonometric Fourier series for all functions of class φ(L) [-π,π) implies the convergence over cubes of the multiple Fourier series and all its conjugates for an arbitrary function f element of φ(L)(log + L) d-1 ) [-π,π) d , d element of N. It follows from this and an earlier result of the author on the convergence almost everywhere of Fourier series of functions of one variable and class L(log + L)(log + log + log + L)) [-π,π) that if f element of L(log + L) d (log + log + log + L)) [-π,π) d , d element of N, then the Fourier series of f and all its conjugates converge over cubes almost everywhere

Mountain Wave Analysis Using Fourier Methods

National Research Council Canada - National Science Library

Roadcap, John R

2007-01-01

...) their requirements for only a coarse horizontal background state. Common traits of Fourier mountain wave models include use of the Boussinesq approximation and neglect of moisture and Coriolis terms...

Edge-augmented Fourier partial sums with applications to Magnetic Resonance Imaging (MRI)

Science.gov (United States)

Larriva-Latt, Jade; Morrison, Angela; Radgowski, Alison; Tobin, Joseph; Iwen, Mark; Viswanathan, Aditya

2017-08-01

Certain applications such as Magnetic Resonance Imaging (MRI) require the reconstruction of functions from Fourier spectral data. When the underlying functions are piecewise-smooth, standard Fourier approximation methods suffer from the Gibbs phenomenon - with associated oscillatory artifacts in the vicinity of edges and an overall reduced order of convergence in the approximation. This paper proposes an edge-augmented Fourier reconstruction procedure which uses only the first few Fourier coefficients of an underlying piecewise-smooth function to accurately estimate jump information and then incorporate it into a Fourier partial sum approximation. We provide both theoretical and empirical results showing the improved accuracy of the proposed method, as well as comparisons demonstrating superior performance over existing state-of-the-art sparse optimization-based methods.

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.

New stable multiply charged negative atomic ions in linearly polarized superintense laser fields

International Nuclear Information System (INIS)

Wei Qi; Kais, Sabre; Moiseyev, Nimrod

2006-01-01

Singly charged negative atomic ions exist in the gas phase and are of fundamental importance in atomic and molecular physics. However, theoretical calculations and experimental results clearly exclude the existence of any stable doubly-negatively-charged atomic ion in the gas phase, only one electron can be added to a free atom in the gas phase. In this report, using the high-frequency Floquet theory, we predict that in a linear superintense laser field one can stabilize multiply charged negative atomic ions in the gas phase. We present self-consistent field calculations for the linear superintense laser fields needed to bind extra one and two electrons to form He - , He 2- , and Li 2- , with detachment energies dependent on the laser intensity and maximal values of 1.2, 0.12, and 0.13 eV, respectively. The fields and frequencies needed for binding extra electrons are within experimental reach. This method of stabilization is general and can be used to predict stability of larger multiply charged negative atomic ions

The resistive plate WELL detector as a single stage thick gaseous multiplier detector

Energy Technology Data Exchange (ETDEWEB)

Bressler, Shikma; Breskin, Amos; Moleri, Luca; Kumar, Ashwini; Pitt, Michael [Department of Particle Physics and Astrophysics, Weizmann Institute of Science (WIS) (Israel); Kudella, Simon [Institut fuer Experimentelle Kernphysik (IEKP), KIT (Germany)

2015-07-01

Gaseous Electron Multiplier (GEM) detector use high electric fields inside the h ole of a foil to achieve a high charge multiplication. As a thicker version of G EMs based on printed circuit board (PCB) structures, Thick Gaseous Electron Multiplier (THGEM) detectors combine the high gain of a GEM foil with the robustness, stability and low production costs of a PCB and allow a large quantity of applications that require the coverage of a large area at low cost and moderate spatial resolution. One application the Weizmann Institute of Science (WIS) develops as a member of the RD51 framework is the Resistive Plate WELL (RPWELL) detector. This single stage detector allows a very stable, discharge free operation at high gain (10{sup 5}). The single stage operation allows a low total height and make s the RPWELL a candidate for the Digital Hadronic Calorimeter (DHCAL) of the International Large Detector (ILD) at the International Linear Collider (ILC). The talk gives an insight into the way the RPWELL works and shows results from the last test beam.

Constitutive analysis to predict the hot deformation behavior of 34CrMo4 steel with an optimum solution method for stress multiplier

International Nuclear Information System (INIS)

Xu, Wujiao; Zou, Mingping; Zhang, Lei

2014-01-01

The hot deformation behaviors of steel 34CrMo4 is investigated by hot compression test with the temperature range of 1073–1373 K and the strain rate range of 0.01–10 s −1 . The flow behaviors of 34CrMo4 steel were characterized based on the true stress–true strain curves. The hyperbolic sine law in Arrhenius type is adopted in the constitutive modeling for 34CrMo4. Solving algorithm of the stress multiplier α in hyperbolic sine law is a key factor to guarantee the constitutive model accuracy. How to solve the stress multiplier α is investigated and an optimum solution method for α is proposed. Meanwhile, the influence of strain is incorporated in constitutive analysis by considering the effect of strain on material constants α, n, Q and A. With the optimum solution method for stress multiplier α proposed, the stress prediction is satisfactory with the higher correlation coefficient, R = 0.988 and the lower average absolute relative error, AARE = 3.44% for the entire strain rate-temperature domain. The optimum solution method for stress multiplier α can also be applied for other materials to predict the flow behavior more accurately. - Highlights: • Isothermal compression tests were conducted to study the flow behavior of 34CrMo4. • The influence of strain is incorporated in constitutive model. • An optimum solution method for stress multiplier α is proposed

Maximum-entropy data restoration using both real- and Fourier-space analysis

International Nuclear Information System (INIS)

Anderson, D.M.; Martin, D.C.; Thomas, E.L.

1989-01-01

An extension of the maximum-entropy (ME) data-restoration method is presented that is sensitive to periodic correlations in data. The method takes advantage of the higher signal-to-noise ratio for periodic information in Fourier space, thus enhancing statistically significant frequencies in a manner which avoids the user bias inherent in conventional Fourier filtering. This procedure incorporates concepts underlying new approaches in quantum mechanics that consider entropies in both position and momentum spaces, although the emphasis here is on data restoration rather than quantum physics. After a fast Fourier transform of the image, the phases are saved and the array of Fourier moduli are restored using the maximum-entropy criterion. A first-order continuation method is introduced that speeds convergence of the ME computation. The restored moduli together with the original phases are then Fourier inverted to yield a new image; traditional real-space ME restoration is applied to this new image completing one stage in the restoration process. In test cases improvement can be obtained from two to four stages of iteration. It is shown that in traditional Fourier filtering spurious features can be induced by selection or elimination of Fourier components without regard to their statistical significance. With the present approach there is no such freedom for the user to exert personal bias, so that features present in the final image and power spectrum are those which have survived the tests of statistical significance in both real and Fourier space. However, it is still possible for periodicities to 'bleed' across sharp boundaries. An 'uncertainty' relation is derived describing the inverse relationship between the resolution of these boundaries and the level of noise that can be eliminated. (orig./BHO)

The net multiplier is a new key sector indicator : Reply to De Mesnard's comment

NARCIS (Netherlands)

Oosterhaven, Jan

Most of the comment of de Mesnard applies to a causal interpretation of the net multiplier that is applied to economically impossible exogenous (changes in) total output. This reply shows that this interpretation is incorrect and that his further argumentation is based on a time inconsistent

The Financial Unlinkage of the Mexican Economy: A Social Accounting Matrix Multiplier Approach for a One-Sector Economy

Directory of Open Access Journals (Sweden)

Andrés Blancas

2003-11-01

Full Text Available This paper addresses the financial unlinkage in Mexico through an accounting multiplier analysis derived from a SAM for a one-sector economy. Such an analysis provides a useful tool to quantify processes of structural financial change in terms of "stylized parameters". We identify and measure the financial unlinkage with financial backward and forward linkage indices derived from the accounting multipliers. The results can also help to the quality of policy decisions by identifying key and weak financial institutions and by giving a better understanding of how an impact of an initial financial injection travels within a structure.

Effect of irradiation angle on the efficiency of formation of multiply charged ions in a laser-produced plasma

International Nuclear Information System (INIS)

Bedilov, M R; Beisembaeva, Kh B; Tsoi, T G; Satybaldiev, T B; Sabitov, M S

2000-01-01

Mass spectrometry is used to investigate the emission behaviour and the characteristics of multiply charged ions in a plasma produced at small angles of incidence of laser radiation (α∼20 0 ) and also at grazing incidence (α∼85 0 ). It is found that upon grazing incidence of the laser radiation onto a target, the efficiency of production of multiply charged ions is reduced compared to that for α∼20 0 . However, this geometry of laser irradiation of solids can be used for the elemental analysis of surface layers of a sample. (interaction of laser radiation with matter. laser plasma)

X-ray stress measurement of ferritic steel using fourier analysis of Debye-Scherrer ring

International Nuclear Information System (INIS)

Fujimoto, Yohei; Sasaki, Toshihiko; Miyazaki, Toshiyuki

2015-01-01

In this study, X-ray stress measurements of ferritic steel based on Fourier analysis are conducted. Taira et al. developed the cosα method for X-ray stress measurements using a two-dimensional X-ray detector. Miyazaki et al. reported that the cosα method can be described more concisely by developing the Fourier series (the Fourier analysis method). The Fourier analysis method is expected to yield the stress measurement with an imperfect Debye-Scherrer ring and there is a possibility that the materials evaluation is different compared with the conventional method, that is, the sin 2 ψ method. In the Fourier analysis method, the strain measured by X-rays is developed as a Fourier series, and all the plane-stress components can be calculated from the Fourier series. In this study, the normal stress calculation was confirmed. In addition, the Fourier-analysis and cosα methods were used for X-ray stress measurements during a four-point bending test on a S45C test piece, and the effectiveness of the Fourier analysis method was confirmed. It was found that the experimental results from the Fourier analysis and cosα methods were nearly identical. In addition, the measurement accuracies of both the methods were equivalent. (author)

Solid phase extraction of Am (III) by resins impregnated with multiply diglycolamide-functionalized ligands

International Nuclear Information System (INIS)

Gujar, R.B.; Ansari, S.A.; Mohapatra, P.K.; Verboom, W.

2016-01-01

Solvent extraction studies with multiply diglycolamide-functionalized extractants such as tripodal diglycolamide (T-DGA) or diglycolamide-functionalized calix(4)arene (C4DGA) ligands have shown excellent results as compared to those of normal DGA ligands such as TODGA. A very high selectivity for Am(III) has been reported with these ligands with respect to U(VI) and Pu(IV). High selectivities and large extraction efficiencies of these ligands towards trivalent f elements were ascribed to a co-operative complexation mechanism. Furthermore, the extraction efficiency of these ligands increased several folds in ionic liquid medium as compared to paraffinic solvents. It was of interest, therefore, to prepare extraction chromatographic resins by impregnation of solvent systems containing these ligands in an ionic liquid. In the present work, solid phase extraction studies were carried out using these two multiply diglycolamide-functionalized extractants, viz. T-DGA (resin I) and C4DGA (resin-II) containing the ionic liquid C 4 mim. NTf 2 impregnated on Chromosorb-W

Encoding Schemes For A Digital Optical Multiplier Using The Modified Signed-Digit Number Representation

Science.gov (United States)

Lasher, Mark E.; Henderson, Thomas B.; Drake, Barry L.; Bocker, Richard P.

1986-09-01

The modified signed-digit (MSD) number representation offers full parallel, carry-free addition. A MSD adder has been described by the authors. This paper describes how the adder can be used in a tree structure to implement an optical multiply algorithm. Three different optical schemes, involving position, polarization, and intensity encoding, are proposed for realizing the trinary logic system. When configured in the generic multiplier architecture, these schemes yield the combinatorial logic necessary to carry out the multiplication algorithm. The optical systems are essentially three dimensional arrangements composed of modular units. Of course, this modularity is important for design considerations, while the parallelism and noninterfering communication channels of optical systems are important from the standpoint of reduced complexity. The authors have also designed electronic hardware to demonstrate and model the combinatorial logic required to carry out the algorithm. The electronic and proposed optical systems will be compared in terms of complexity and speed.

Size effects in non-linear heat conduction with flux-limited behaviors

Science.gov (United States)

Li, Shu-Nan; Cao, Bing-Yang

2017-11-01

Size effects are discussed for several non-linear heat conduction models with flux-limited behaviors, including the phonon hydrodynamic, Lagrange multiplier, hierarchy moment, nonlinear phonon hydrodynamic, tempered diffusion, thermon gas and generalized nonlinear models. For the phonon hydrodynamic, Lagrange multiplier and tempered diffusion models, heat flux will not exist in problems with sufficiently small scale. The existence of heat flux needs the sizes of heat conduction larger than their corresponding critical sizes, which are determined by the physical properties and boundary temperatures. The critical sizes can be regarded as the theoretical limits of the applicable ranges for these non-linear heat conduction models with flux-limited behaviors. For sufficiently small scale heat conduction, the phonon hydrodynamic and Lagrange multiplier models can also predict the theoretical possibility of violating the second law and multiplicity. Comparisons are also made between these non-Fourier models and non-linear Fourier heat conduction in the type of fast diffusion, which can also predict flux-limited behaviors.

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.

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

Validation of the multiplier method for leg-length predictions on a large European cohort and an assessment of the effect of physiological age on predictions.

Science.gov (United States)

Aird, J J; Cheesman, C L; Schade, A T; Monsell, F P

2017-01-01

The Avon Longitudinal Study of Parents and Children (ALSPAC) prospective cohort was used to determine the accuracy of the Paley multiplier method for predicting leg length. Using menarche as a proxy, physiological age was then used to increase the accuracy of the multiplier. Chronological age was corrected in female patients over the age of eight years with documented date of first menses. Final sub-ischial leg length and predicted final leg length were predicted for all data points. Good correlation was demonstrated between the Paley and ALSPAC data. The average error in prediction depended on the time of assessment, tending to improve as the child got older. It varied from 2.2 cm at the age of seven years to 1.8 cm at the age of 14 years. When chronological age was corrected, the accuracy of multiplier increased. Age correction of 50% improved multiplier predictions by up to 28%. There appears to have been no significant change in growth trajectories of the two populations who were chronologically separated by 40 years. While the Paley data were based on extracting trends from averaged data, the ALSPAC dataset provides descriptive statistics from which it is possible to compare populations and assess the accuracy of the multiplier method. The data suggest that the accuracy improves as the patient gets close to the average skeletal maturity but that results need to be interpreted in conjunction with a radiological assessment of the growth plates. The magnitude of the errors in prediction suggest that when using the multiplier, the clinician must remain vigilant and prepared to perform a contralateral epiphyseodisis if the prediction proves to be wrong. The data suggest a relationship between the multiplier and menarche. There appears to be a factorisation and when accounting for physiological age, one needs to correct by 50% of the difference between chronological and physiological age.

Aiding the search: Examining individual differences in multiply-constrained problem solving.

Science.gov (United States)

Ellis, Derek M; Brewer, Gene A

2018-07-01

Understanding and resolving complex problems is of vital importance in daily life. Problems can be defined by the limitations they place on the problem solver. Multiply-constrained problems are traditionally examined with the compound remote associates task (CRAT). Performance on the CRAT is partially dependent on an individual's working memory capacity (WMC). These findings suggest that executive processes are critical for problem solving and that there are reliable individual differences in multiply-constrained problem solving abilities. The goals of the current study are to replicate and further elucidate the relation between WMC and CRAT performance. To achieve these goals, we manipulated preexposure to CRAT solutions and measured WMC with complex-span tasks. In Experiment 1, we report evidence that preexposure to CRAT solutions improved problem solving accuracy, WMC was correlated with problem solving accuracy, and that WMC did not moderate the effect of preexposure on problem solving accuracy. In Experiment 2, we preexposed participants to correct and incorrect solutions. We replicated Experiment 1 and found that WMC moderates the effect of exposure to CRAT solutions such that high WMC participants benefit more from preexposure to correct solutions than low WMC (although low WMC participants have preexposure benefits as well). Broadly, these results are consistent with theories of working memory and problem solving that suggest a mediating role of attention control processes. Published by Elsevier Inc.

Economic impacts from energy efficiency programs - Variations in multiplier effects by program type and region. Volume 1

International Nuclear Information System (INIS)

Gardner, John; Skumatz, Lisa

2007-01-01

Research indicates that the value of omitted program effects - specifically non-energy benefits (NEBs) - represent a significant share of overall program impacts. One of the largest components of societal benefits is the direct and indirect economic and job creation effects stimulated by the investment in conservation on behalf of the program. The literature has indicated that the valuations assigned to this category of these categories can be large, but much of the literature overstates the impact of economic NEBs. We conducted extensive research to develop reliable and defensible estimates of these benefits categories. This study used input-output analysis to update the economic multipliers for NEBs in several ways. Net: Developed 'net' estimates of the multipliers (rather than 'gross' factors)Variations by Region: Estimated multipliers for multiple states and for the entire US; Variations by Program Type: Developed estimates based on different types or categories of programs (e.g weatherization vs. new construction vs. appliance programs, etc.), Variations in Baseline Assumptions: Different assumptions about where the expenditures are transferred 'from' for the net analysis (e.g. from 'generation', from a mixed market basket, etc.); and Variations over Time: Used data from multiple time periods to examine changes in the size of multipliers over time. We examined the results by state, by program type, and over time and found dramatic differences in the economic impacts by program type and territory under consideration. The results provide estimates of the economic impacts derived from the program; however, for communities or utilities with economic development goals, the results can be used to help select between program alternatives. The results are new, and the revised figures have been used to compute more reliable and tailored estimates of economic non-energy benefits that can be applied in regulatory tests

Decay properties of linear thermoelastic plates: Cattaneo versus Fourier law

KAUST Repository

Said-Houari, Belkacem

2013-02-01

In this article, we investigate the decay properties of the linear thermoelastic plate equations in the whole space for both Fourier and Cattaneo\\'s laws of heat conduction. We point out that while the paradox of infinite propagation speed inherent in Fourier\\'s law is removed by changing to the Cattaneo law, the latter always leads to a loss of regularity of the solution. The main tool used to prove our results is the energy method in the Fourier space together with some integral estimates. We prove the decay estimates for initial data U0 ∈ Hs(ℝ) ∩ L1(ℝ). In addition, by restricting the initial data to U0 ∈ Hs(ℝ) ∩ L1,γ(ℝ) and γ ∈ [0, 1], we can derive faster decay estimates with the decay rate improvement by a factor of t-γ/2. © 2013 Copyright Taylor and Francis Group, LLC.

SU-E-QI-08: Fourier Properties of Cone Beam CT Projection

International Nuclear Information System (INIS)

Bai, T; Yan, H; Jia, X; Jiang, Steve B.; Mou, X

2014-01-01

Purpose: To explore the Fourier properties of cone beam CT (CBCT) projections and apply the property to directly estimate noise level of CBCT projections without any prior information. Methods: By utilizing the property of Bessel function, we derivate the Fourier properties of the CBCT projections for an arbitrary point object. It is found that there exists a double-wedge shaped region in the Fourier space where the intensity is approximately zero. We further derivate the Fourier properties of independent noise added to CBCT projections. The expectation of the square of the module in any point of the Fourier space is constant and the value approximately equals to noise energy. We further validate the theory in numerical simulations for both a delta function object and a NCAT phantom with different levels of noise added. Results: Our simulation confirmed the existence of the double-wedge shaped region in Fourier domain for the x-ray projection image. The boundary locations of this region agree well with theoretical predictions. In the experiments of estimating noise level, the mean relative error between the theory estimation and the ground truth values is 2.697%. Conclusion: A novel theory on the Fourier properties of CBCT projections has been discovered. Accurate noise level estimation can be achieved by applying this theory directly to the measured CBCT projections. This work was supported in part by NIH(1R01CA154747-01), NSFC((No. 61172163), Research Fund for the Doctoral Program of Higher Education of China (No. 20110201110011) and China Scholarship Council

Database for inelastic collisions of lithium atoms with electrons, protons, and multiply charged ions

NARCIS (Netherlands)

Schweinzer, J; Brandenburg, R; Bray, [No Value; Hoekstra, R; Aumayr, F; Janev, RK; Winter, HP

New experimental and theoretical cross-section data for inelastic collision processes of Li atoms in the ground state and excited states (up to n = 4) with electrons, protons, and multiply charged ions have been reported since the database assembled by Wutte et al. [ATOMIC DATA AND NUCLEAR DATA

Pointwise Multipliers on Spaces of Homogeneous Type in the Sense of Coifman and Weiss

Directory of Open Access Journals (Sweden)

Yanchang Han

2014-01-01

homogeneous type in the sense of Coifman and Weiss, pointwise multipliers of inhomogeneous Besov and Triebel-Lizorkin spaces are obtained. We make no additional assumptions on the quasi-metric or the doubling measure. Hence, the results of this paper extend earlier related results to a more general setting.

Introduction to partial differential equations from Fourier series to boundary-value problems

CERN Document Server

Broman, Arne

2010-01-01

This well-written, advanced-level text introduces students to Fourier analysis and some of its applications. The self-contained treatment covers Fourier series, orthogonal systems, Fourier and Laplace transforms, Bessel functions, and partial differential equations of the first and second orders. Over 260 exercises with solutions reinforce students' grasp of the material. 1970 edition.

Ad Hoc Microphone Array Beamforming Using the Primal-Dual Method of Multipliers

DEFF Research Database (Denmark)

Tavakoli, Vincent Mohammad; Jensen, Jesper Rindom; Heusdens, Richard

2016-01-01

In the recent years, there have been increasing amount of researches aiming at optimal beamforming with ad hoc microphone arrays, mostly with fusion-based schemes. However, huge amount of computational complexity and communication overhead impede many of these algorithms from being useful in prac...... the distributed linearly-constrained minimum variance beamformer using the the state of the art primal-dual method of multipliers. We study the proposed algorithm with an experiment....

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)

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

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)

Fourier spectral of PalmCode as descriptor for palmprint recognition

NARCIS (Netherlands)

Ruan, Qiuqi; Spreeuwers, Lieuwe Jan; Veldhuis, Raymond N.J.; Mu, Meiru

Study on automatic person recognition by palmprint is currently a hot topic. In this paper, we propose a novel palmprint recognition method by transforming the typical palmprint phase code feature into its Fourier frequency domain. The resulting real-valued Fourier spectral features are further

Fourier analysis of the parametric resonance in neutrino oscillations

International Nuclear Information System (INIS)

Koike, Masafumi; Ota, Toshihiko; Saito, Masako; Sato, Joe

2009-01-01

Parametric enhancement of the appearance probability of the neutrino oscillation under the inhomogeneous matter is studied. Fourier expansion of the matter density profile leads to a simple resonance condition and manifests that each Fourier mode modifies the energy spectrum of oscillation probability at around the corresponding energy; below the MSW resonance energy, a large-scale variation modifies the spectrum in high energies while a small-scale one does in low energies. In contrast to the simple parametric resonance, the enhancement of the oscillation probability is itself an slow oscillation as demonstrated by a numerical analysis with a single Fourier mode of the matter density. We derive an analytic solution to the evolution equation on the resonance energy, including the expression of frequency of the slow oscillation.

Combined Helmholtz Integral Equation - Fourier series formulation of acoustical radiation and scattering problems

CSIR Research Space (South Africa)

Fedotov, I

2006-07-01

Full Text Available The Combined Helmholtz Integral Equation – Fourier series Formulation (CHIEFF) is based on representation of a velocity potential in terms of Fourier series and finding the Fourier coefficients of this expansion. The solution could be substantially...

The tomography inside of a Fourier Optics course: some opto-mechanical illustrative arrays

International Nuclear Information System (INIS)

Rodriguez Z, G.; Rodriguez V, R.; Luna C, A.

1999-01-01

The introduction of tomography as an advanced topic to be included in a Fourier optics course at graduated level is proposed. It is shown a possible presentation sequence which features the use of typical Fourier optics techniques, as well as some well known opto-mechanical devices as examples. Finally, a simplified apparatus which illustrates the central Fourier theorem as an experimental project on Fourier optics is described. Corresponding experimental results are also shown. (Author)

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.

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

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

Fabrication and measurement of gas electron multiplier

International Nuclear Information System (INIS)

Zhang Minglong; Xia Yiben; Wang Linjun; Gu Beibei; Wang Lin; Yang Ying

2005-01-01

Gas electron multiplier (GEM) with special performance has been widely used in the field of radiation detectors. In this work, GEM film was fabricated using a 50 μm -thick kapton film by the therma evaporation and laser masking drilling technique. GEM film has many uniformly arrayed holes with a diameter of 100 μm and a gap of 223 μm. It was then set up to a gas-flowing detector with an effective area of 3 x 3 cm 2 , 5.9 keV X-ray generated from a 55 Fe source was used to measure the pulse height distribution of GEM operating at various high voltage and gas proportion. The effect of high potential and gas proportion on the count rate and the energy resolution was discussed in detail. The results indicate that GEM has a very high ratio of signal to noise and better energy resolution of 18.2%. (authors)

An Extension of Fourier-Wavelet Volume Rendering by View Interpolation

NARCIS (Netherlands)

Westenberg, Michel A.; Roerdink, Jos B.T.M.

2001-01-01

This paper describes an extension to Fourier-wavelet volume rendering (FWVR), which is a Fourier domain implementation of the wavelet X-ray transform. This transform combines integration along the line of sight with a simultaneous 2-D wavelet transform in the view plane perpendicular to this line.

Inference for multivariate regression model based on multiply imputed synthetic data generated via posterior predictive sampling

Science.gov (United States)

Moura, Ricardo; Sinha, Bimal; Coelho, Carlos A.

2017-06-01

The recent popularity of the use of synthetic data as a Statistical Disclosure Control technique has enabled the development of several methods of generating and analyzing such data, but almost always relying in asymptotic distributions and in consequence being not adequate for small sample datasets. Thus, a likelihood-based exact inference procedure is derived for the matrix of regression coefficients of the multivariate regression model, for multiply imputed synthetic data generated via Posterior Predictive Sampling. Since it is based in exact distributions this procedure may even be used in small sample datasets. Simulation studies compare the results obtained from the proposed exact inferential procedure with the results obtained from an adaptation of Reiters combination rule to multiply imputed synthetic datasets and an application to the 2000 Current Population Survey is discussed.

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.

Fourier diffraction theorem for diffusion-based thermal tomography

International Nuclear Information System (INIS)

Baddour, Natalie

2006-01-01

There has been much recent interest in thermal imaging as a method of non-destructive testing and for non-invasive medical imaging. The basic idea of applying heat or cold to an area and observing the resulting temperature change with an infrared camera has led to the development of rapid and relatively inexpensive inspection systems. However, the main drawback to date has been that such an approach provides mainly qualitative results. In order to advance the quantitative results that are possible via thermal imaging, there is interest in applying techniques and algorithms from conventional tomography. Many tomography algorithms are based on the Fourier diffraction theorem, which is inapplicable to thermal imaging without suitable modification to account for the attenuative nature of thermal waves. In this paper, the Fourier diffraction theorem for thermal tomography is derived and discussed. The intent is for this thermal-diffusion based Fourier diffraction theorem to form the basis of tomographic reconstruction algorithms for quantitative thermal imaging

Error Analysis for Fourier Methods for Option Pricing

KAUST Repository

Häppölä, Juho

2016-01-06

We provide a bound for the error committed when using a Fourier method to price European options when the underlying follows an exponential Levy dynamic. The price of the option is described by a partial integro-differential equation (PIDE). Applying a Fourier transformation to the PIDE yields an ordinary differential equation that can be solved analytically in terms of the characteristic exponent of the Levy process. Then, a numerical inverse Fourier transform allows us to obtain the option price. We present a novel bound for the error and use this bound to set the parameters for the numerical method. We analyze the properties of the bound for a dissipative and pure-jump example. The bound presented is independent of the asymptotic behaviour of option prices at extreme asset prices. The error bound can be decomposed into a product of terms resulting from the dynamics and the option payoff, respectively. The analysis is supplemented by numerical examples that demonstrate results comparable to and superior to the existing literature.

Statistics of electron multiplication in a multiplier phototube; Iterative method

International Nuclear Information System (INIS)

Ortiz, J. F.; Grau, A.

1985-01-01

In the present paper an iterative method is applied to study the variation of dynode response in the multiplier phototube. Three different situation are considered that correspond to the following ways of electronic incidence on the first dynode: incidence of exactly one electron, incidence of exactly r electrons and incidence of an average r electrons. The responses are given for a number of steps between 1 and 5, and for values of the multiplication factor of 2.1, 2.5, 3 and 5. We study also the variance, the skewness and the excess of jurtosis for different multiplication factors. (Author) 11 refs

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.)

Meniscal tears: comparison of half-Fourier technique and conventional MR imaging

International Nuclear Information System (INIS)

Shabana, Wael; Maeseneer, Michel de; Machiels, Freddy; Ridder, Filip de; Osteaux, Michel

2003-01-01

Purpose: To determine whether half-Fourier MR image acquisition technique can provide similar information to that of conventional MR acquisition technique for evaluation of meniscal tears. Materials and methods: We studied 101 menisci in 52 patients who were referred for evaluation of meniscal tears. Sagittal MR images of the knee were obtained for all patients by using proton density and T2-weighted SE sequences on a 1-T clinical system. The half-Fourier technique and conventional technique were used for all patients. All other imaging parameters were identical for both sequences (TR/TE=2400/20,70; 3 mm slice thickness; 200x256 matrix; field of view, 200; one signal acquired). Both sets of images were filmed with standard window and level settings. Images were randomised and interpreted independently by two radiologists for the presence of meniscal tears. Images were also subjectively assessed for image quality using a five-point grading scale. Results: On half-Fourier images, Reader 1 interpreted 23 menisci as torn, compared to 28 for Reader 2. On conventional images, Reader 1 interpreted 24 menisci as torn, compared to 26 for Reader 2. Agreement between interpretation of the conventional and that of the half-Fourier images was 99% for Reader 1, and 98% for Reader 2. Agreement between readers for the half-Fourier images was 95%, and for the conventional images 96%. No statistically significant difference was found in the subjective evaluation of image quality between the conventional and half-Fourier images. Conclusion: The half-Fourier acquisition technique compares favourably with the conventional technique for the evaluation of meniscal tears

New focus on Fourier optics techniques

NARCIS (Netherlands)

Calvo, M.L.; Alieva, T.; Bastiaans, M.J.; Rodrigo Martín-Romo, J.A.; Rodríguez Merlo, D.; Vlad, V.I.

2004-01-01

We present a short overview on the application of fractional cyclic and linear canonical transformations to optical signal processing and dedicate some of the discussions to the particular features found in the fractional Fourier transform domain.

Non-Fourier heat conduction and phase transition in laser ablation of polytetrafluoroethylene (PTFE)

Science.gov (United States)

Zhang, Yu; Zhang, Daixian; Wu, Jianjun; Li, Jian; He, Zhaofu

2017-11-01

The phase transition in heat conduction of polytetrafluoroethylene-like polymers was investigated and applied in many fields of science and engineering. Considering more details including internal absorption of laser radiation, reflectivity of material and non-Fourier effect etc., the combined heat conduction and phase transition in laser ablation of polytetrafluoroethylene were modeled and investigated numerically. The thermal and mechanic issues in laser ablation were illustrated and analyzed. Especially, the phenomenon of temperature discontinuity formed in the combined phase transition and non-Fourier heat conduction was discussed. Comparisons of target temperature profiles between Fourier and non-Fourier heat conduction in melting process were implemented. It was indicated that the effect of non-Fourier plays an important role in the temperature evolvement. The effect of laser fluence was proven to be significant and the thermal wave propagation was independent on the laser intensity for the non-Fourier heat conduction. Besides, the effect of absorption coefficients on temperature evolvements was studied. For different ranges of absorption coefficients, different temperature evolvements can be achieved. The above numerical simulation provided insight into physical processes of combined non-Fourier heat conduction and phase transition in laser ablation.

Improved 64-bit Radix-16 Booth Multiplier Based on Partial Product Array Height Reduction

DEFF Research Database (Denmark)

Antelo, Elisardo; Montuschi, Paolo; Nannarelli, Alberto

2016-01-01

, a reduction of one unit in the maximum height is achieved. This reduction may add flexibility during the design of the pipelined multiplier to meet the design goals, it may allow further optimizations of the partial product array reduction stage in terms of area/delay/power and/or may allow additional addends...

Understanding the size of the government spending multiplier: It's in the sign

OpenAIRE

Barnichon, Régis; Matthes, Christian

2016-01-01

Despite intense scrutiny, estimates of the government spending multiplier remain highly uncertain, with values ranging from 0.5 to 2. While an increase in government spending is generally assumed to have the same (mirror-image) effect as a decrease in government spending, we show that relaxing this assumption is important to understand the effects of fiscal policy. Regardless of whether we identify government spending shocks from (i) a narrative approach, or (ii) a timing restr...