Energy Technology Data Exchange (ETDEWEB)
Gavarini, St
2002-11-01
Rare earth aluminosilicate glasses are known for their interesting mechanical and optical properties. Recent studies have shown that their chemical durability was very good too, such they have the potential to be used in the nuclear industry for the specific immobilization of trivalent actinides. Initial dissolution rates of LaYSiAlO and CeYSiAlO were determined using a Soxhlet device (dynamic leaching). The differences linked to the nature of the rare earth element were studied by synthesizing analogous glasses that only differed in their rare earth element composition (%at.): Y-5%, La-5 %, Si-15%, Al-10% O-65%. The influence of pH on the dissolution mechanisms and kinetics was also studied by static leaching tests performed in dilute solutions of NaOH or HNO{sub 3}. Electronic defects and collision cascades, induced by a-disintegration of radioelements confined in storage matrix, can cause important modifications in the glass structure and, thus, influence its chemical durability. To simulate these effects, glass samples were irradiated with {beta} particles and heavy ions accelerated to 2,5 MeV and 200 keV, respectively. Monoliths were then leached in static bi-distilled water (pH{>=}{>=} 5.5) for one month in an autoclave heated to 90 degrees C. Initially, the structural changes caused by irradiation were determined using Raman, NMR and EPR spectroscopies. Ion {mu}-beams, SEM-EDS and XPS analysis were also performed to evaluate the potential modifications of the superficial composition. Finally, the leaching behavior was studied, for both irradiated and unirradiated samples, through solution and solid elementary characterization. (author)
Van Koetsem, Frederik; Verstraete, Simon; Van der Meeren, Paul; Du Laing, Gijs
2015-10-01
The stability of engineered nanoparticles (ENPs) in complex aqueous matrices is a key determinant of their fate and potential toxicity towards the aquatic environment and human health. Metal oxide nanoparticles, such as CeO2 ENPs, are increasingly being incorporated into a wide range of industrial and commercial applications, which will undoubtedly result in their (unintentional) release into the environment. Hereby, the behaviour and fate of CeO2 ENPs could potentially serve as model for other nanoparticles that possess similar characteristics. The present study examined the stability and settling of CeO2 ENPs (7.3±1.4 nm) as well as Ce(3+) ions in 10 distinct natural surface waters during 7d, under stagnant and isothermal experimental conditions. Natural water samples were collected throughout Flanders (Belgium) and were thoroughly characterized. For the majority of the surface waters, a substantial depletion (>95%) of the initially added CeO2 ENPs was observed just below the liquid surface of the water samples after 7d. In all cases, the reduction was considerably higher for CeO2 ENPs than for Ce(3+) ions (CeO2 ENPs (R(2)≥0.998) and Ce(3+) ions (R(2)≥0.812) from the water column, at least in case notable sedimentation occurred over time. Solution-pH appeared to be a prime parameter governing nanoparticle colloidal stability. Moreover, the suspended solids (TSS) content also seemed to be an important factor affecting the settling rate and residual fraction of CeO2 ENPs as well as Ce(3+) ions in natural surface waters. Correlation results also suggest potential association and co-precipitation of CeO2 ENPs with aluminium- and iron-containing natural colloidal material. The CeO2 ENPs remained stable in dispersion in surface water characterized by a low pH, ionic strength (IS), and TSS content, indicating the eventual stability and settling behaviour of the nanoparticles was likely determined by a combination of physicochemical parameters. Finally, ionic
Structural, Optical and AC Electrical Properties of Ce3+-Doped TiO2-SiO2 Matrices
Vidyadharan, Viji; Vasudevan, Prathibha; Karthika, S.; Joseph, Cyriac; Unnikrishnan, N. V.; Biju, P. R.
2015-08-01
We report the structural, photoluminescence and alternating current (AC) electrical properties of Ce3+-doped titanosilicate matrices prepared by nonhydrolytic sol-gel method, with different annealing temperatures. The structural characterization of the prepared samples was done by x-ray diffraction, energy dispersive spectrum and Fourier transform infrared spectroscopy measurements. The thermal stability of the prepared matrices was studied by the differential scanning calorimetric analysis. The photoluminescence spectrum shows two luminescence bands centered at 360 nm and 464 nm corresponding to the transitions 2D3/2 to 2F7/2 and 2F5/2, respectively. The dielectric responses of the samples were investigated for the frequency range 1 kHz-3 MHz at room temperature. The variation of AC conductivity, real part of dielectric constant ɛ' and imaginary part of dielectric constant ɛ″ with frequency were also studied. The Cole-Cole parameters were calculated and the semicircles observed in the plots indicate a single relaxation process which can be modelled by an equivalent parallel resistor-capacitor circuit.
Udpegning af potentielle sorte pletter via floating car data
DEFF Research Database (Denmark)
Splid Svendsen, Martin; Tradisauskas, Nerius; Lahrmann, Harry
2008-01-01
Formålet med dette paper er at undersøge, om det er muligt at udpege potentielle sorte pletter via floating car data. Der er i projektet udført teoretiske litteraturstudier for at skabe et grundlag for det senere analysearbejde, som danner baggrund for analysearbejdet. Dataene stammer fra Aalborg...
Natural Gas Potential of the United States Ressources potentielles en gaz naturel des États Unis
Directory of Open Access Journals (Sweden)
Kent H. C.
2006-10-01
principaux Louisiane méridionale, Alaska et ta région du Mid-Continent qui groupe l'Oklahoma, le Kansas et l'appendice du Texas ditPanhandle . A peu près 50 % des ressources potentielles se trouvent dans quatre zones : les Etats du nord et du centre des Rocheuses, la région du Mid-Continent, le plateau continental au large de l'Alaska et celui de la Louisiane. Les prévisions indiquent que ces sources potentielles, Alaska inclus, pourraient continuer à fournir une quantité annuelle de l'ordre de celle qui est actuellement produite aux États-Unis, et cela jusque vers l'an 2000. Depuis 1968, les réserves prouvées ont diminué dans les 48 premiers États. Ce déclin peut être attribué en partie au ralentissement de l'activité de forage de 1956 à 1972, mais l'emplacement et la profondeur des puits sont aussi des facteurs importants. Environ 14 % de tous les puits forés aux États-Unis en 1978 étaient des forages d'exploration nouvelle et seulement 4 % des sondages couronnés de succès comme producteurs de gaz ont été forés comme puits d'exploration nouvelle. En 1977, 80 % des puits mis en production étaient situés dans des secteurs et à des profondeurs où seulement 22 % des ressources potentielles en gaz naturel sont censées exister. En clair, il faut réorienter l'exploration et le forage vers les régions où l'on espère de grandes ressources potentielles de gaz, pour se préparer aux rendez-vous des besoins à venir.
Potentielle varmebesparelser ved løbende bygningsrenovering frem til 2050
DEFF Research Database (Denmark)
Wittchen, Kim Bjarne; Kragh, Jesper; Aggerholm, Søren
Rapporten præsenterer analyser af de potentielle nettovarmebesparelser ved løbende bygningsrenovering fremmod 2050, hvis bygningsdelene efterisoleres i henhold til krav, som kunne stilles i Bygningsreglementet på det tidspunkt, hvor bygningerne alligevel skal have foretaget almindelig renovering ...
Albrecht, S.A.; Schols, H.A.; Klarenbeek, B.; Voragen, A.G.J.; Gruppen, H.
2010-01-01
The analysis and quantification of (galacto)oligosaccharides from food matrices demands both a reproducible extraction method as well as a sensitive and accurate analytical method. Three typical matrices, namely, infant formula, fruit juice, and a maltodextrin-rich preparation, to which a commercial
Directory of Open Access Journals (Sweden)
JEGO S.
2002-04-01
Full Text Available Dans le cadre du programme de restauration de l’esturgeon européen Acipenser sturio L. 1758, nous avons recensé et caractérisé l’ensemble des frayères potentielles de cette espèce sur les fleuves Garonne et Dordogne. L’objectif de ce travail était de réaliser un premier bilan sur l’état actuel de ces zones et d’évaluer leur possible utilisation comme frayère. Avant ce travail, les seules données disponibles étaient constituées par une liste de frayères et de zones de pêche de géniteurs répertoriées en 1952 et 1980 par enquêtes auprès des pêcheurs. Une analyse des données publiées sur les autres espèces d’esturgeons a permis de cerner les principales caractéristiques physiques d’une frayère d’esturgeons. En croisant les informations issues de ces 2 sources, historique et bibliographique, nous avons retenu une liste de sites qui ont ensuite été caractérisés lors de campagnes sur le terrain. Cette caractérisation a porté sur la bathymétrie, le courant, la nature du substrat, la position dans le paysage et les impacts anthropiques immédiats. Les résultats de cette étude ont montré que la majorité des 28 sites étudiés répondait aux caractéristiques d’une frayère d’esturgeon en terme de courant, profondeur et substrat. Ils pouvaient donc être considérés comme frayères potentielles et leur capacité d’accueil était suffisante à moyen terme. Néanmoins il apparaît nécessaire de protéger réglementairement l’ensemble de ces sites afin de les soustraire aux impacts négatifs d’activité anthropiques.
Mehta, Madan Lal
1990-01-01
Since the publication of Random Matrices (Academic Press, 1967) so many new results have emerged both in theory and in applications, that this edition is almost completely revised to reflect the developments. For example, the theory of matrices with quaternion elements was developed to compute certain multiple integrals, and the inverse scattering theory was used to derive asymptotic results. The discovery of Selberg's 1944 paper on a multiple integral also gave rise to hundreds of recent publications. This book presents a coherent and detailed analytical treatment of random matrices, leading
Stephanov, M A; Wettig, T
2005-01-01
We review elementary properties of random matrices and discuss widely used mathematical methods for both hermitian and nonhermitian random matrix ensembles. Applications to a wide range of physics problems are summarized. This paper originally appeared as an article in the Wiley Encyclopedia of Electrical and Electronics Engineering.
Krylov, Piotr
2017-01-01
This monograph is a comprehensive account of formal matrices, examining homological properties of modules over formal matrix rings and summarising the interplay between Morita contexts and K theory. While various special types of formal matrix rings have been studied for a long time from several points of view and appear in various textbooks, for instance to examine equivalences of module categories and to illustrate rings with one-sided non-symmetric properties, this particular class of rings has, so far, not been treated systematically. Exploring formal matrix rings of order 2 and introducing the notion of the determinant of a formal matrix over a commutative ring, this monograph further covers the Grothendieck and Whitehead groups of rings. Graduate students and researchers interested in ring theory, module theory and operator algebras will find this book particularly valuable. Containing numerous examples, Formal Matrices is a largely self-contained and accessible introduction to the topic, assuming a sol...
Inverse m-matrices and ultrametric matrices
Dellacherie, Claude; San Martin, Jaime
2014-01-01
The study of M-matrices, their inverses and discrete potential theory is now a well-established part of linear algebra and the theory of Markov chains. The main focus of this monograph is the so-called inverse M-matrix problem, which asks for a characterization of nonnegative matrices whose inverses are M-matrices. We present an answer in terms of discrete potential theory based on the Choquet-Deny Theorem. A distinguished subclass of inverse M-matrices is ultrametric matrices, which are important in applications such as taxonomy. Ultrametricity is revealed to be a relevant concept in linear algebra and discrete potential theory because of its relation with trees in graph theory and mean expected value matrices in probability theory. Remarkable properties of Hadamard functions and products for the class of inverse M-matrices are developed and probabilistic insights are provided throughout the monograph.
Energy Technology Data Exchange (ETDEWEB)
Zyczkowski, Karol [Centrum Fizyki Teoretycznej, Polska Akademia Nauk, Al. Lotnikow 32/44, 02-668 Warsaw (Poland); Kus, Marek [Centrum Fizyki Teoretycznej, Polska Akademia Nauk, Al. Lotnikow 32/44, 02-668 Warsaw (Poland); Slomczynski, Wojciech [Instytut Matematyki, Uniwersytet Jagiellonski, ul. Reymonta 4, 30-059 Cracow (Poland); Sommers, Hans-Juergen [Fachbereich 7 Physik, Universitaet Essen, 45117 Essen (Germany)
2003-03-28
An ensemble of random unistochastic (orthostochastic) matrices is defined by taking squared moduli of elements of random unitary (orthogonal) matrices distributed according to the Haar measure on U(N) (or O(N)). An ensemble of symmetric unistochastic matrices is obtained with use of unitary symmetric matrices pertaining to the circular orthogonal ensemble. We study the distribution of complex eigenvalues of bistochastic, unistochastic and orthostochastic matrices in the complex plane. We compute averages (entropy, traces) over the ensembles of unistochastic matrices and present inequalities concerning the entropies of products of bistochastic matrices.
Zyczkowski, K.; Slomczynski, W.; Kus, M.; Sommers, H. -J.
2001-01-01
An ensemble of random unistochastic (orthostochastic) matrices is defined by taking squared moduli of elements of random unitary (orthogonal) matrices distributed according to the Haar measure on U(N) (or O(N), respectively). An ensemble of symmetric unistochastic matrices is obtained with use of unitary symmetric matrices pertaining to the circular orthogonal ensemble. We study the distribution of complex eigenvalues of bistochastic, unistochastic and ortostochastic matrices in the complex p...
Métagermanité et affinité potentielle : la relation de mariage en Inde et en Amazonie
Directory of Open Access Journals (Sweden)
Anne-Christine Taylor
2009-03-01
Full Text Available Métagermanité et affinité potentielle : la relation de mariage en Inde et en Amazonie. Cette contribution évoque le travail de théorisation du système de parenté dit dravidien mené depuis une quinzaine d’années, à partir des écrits de Louis Dumont, en Inde et en Amazonie. L’auteur met en parallèle et commente les « révisions » de l’approche dumontienne développées respectivement par Raymond Jamous dans son livre sur la relation de métagermanité et par Eduardo Viveiros de Castro, en soulignant les perspectives qu’elles ouvrent notamment pour l’étude du statut cosmologique — très contrasté — du mariage en Inde du Sud et en Amazonie.Meta-germanity and meta-affinity: an Indo-Amazonian comparison. This article considers the work of theorization of the Dravidian kinship system, based on the writings of Louis Dumont, conducted over the last fifteen years in India and Amazonia. The author compares and comments on the “revisions” of the Dumontian approach developed by Raymond Jamous in his book on the relation of meta-germanity and by Eduardo Viveiros de Castro. She highlights the perspectives opened up by these revisions, especially for the study of the very different cosmological status of marriage in southern India and in Amazonia.
GENERALIZED NEKRASOV MATRICES AND APPLICATIONS
Institute of Scientific and Technical Information of China (English)
Mingxian Pang; Zhuxiang Li
2003-01-01
In this paper, the concept of generalized Nekrasov matrices is introduced, some properties of these matrices are discussed, obtained equivalent representation of generalized diagonally dominant matrices.
Introduction into Hierarchical Matrices
Litvinenko, Alexander
2013-12-05
Hierarchical matrices allow us to reduce computational storage and cost from cubic to almost linear. This technique can be applied for solving PDEs, integral equations, matrix equations and approximation of large covariance and precision matrices.
BLOCK H-MATRICES AND SPECTRUM OF BLOCK MATRICES
Institute of Scientific and Technical Information of China (English)
黄廷祝; 黎稳
2002-01-01
The block H-matrices are studied by the concept of G-functions, several concepts of block matrices are introduced. Equivalent characters of block H-matrices are obtained. Spectrum localizations claracterized by Gfunctions for block matrices are got.
Circulant conference matrices for new complex Hadamard matrices
Dita, Petre
2011-01-01
The circulant real and complex matrices are used to find new real and complex conference matrices. With them we construct Sylvester inverse orthogonal matrices by doubling the size of inverse complex conference matrices. When the free parameters take values on the unit circle the inverse orthogonal matrices transform into complex Hadamard matrices. The method is used for $n=6$ conference matrices and in this way we find new parametrisations of Hadamard matrices for dimension $ n=12$.
Energy Technology Data Exchange (ETDEWEB)
Cappellini, Valerio [' Mark Kac' Complex Systems Research Centre, Uniwersytet Jagiellonski, ul. Reymonta 4, 30-059 Krakow (Poland); Sommers, Hans-Juergen [Fachbereich Physik, Universitaet Duisburg-Essen, Campus Duisburg, 47048 Duisburg (Germany); Bruzda, Wojciech; Zyczkowski, Karol [Instytut Fizyki im. Smoluchowskiego, Uniwersytet Jagiellonski, ul. Reymonta 4, 30-059 Krakow (Poland)], E-mail: valerio@ictp.it, E-mail: h.j.sommers@uni-due.de, E-mail: w.bruzda@uj.edu.pl, E-mail: karol@cft.edu.pl
2009-09-11
Ensembles of random stochastic and bistochastic matrices are investigated. While all columns of a random stochastic matrix can be chosen independently, the rows and columns of a bistochastic matrix have to be correlated. We evaluate the probability measure induced into the Birkhoff polytope of bistochastic matrices by applying the Sinkhorn algorithm to a given ensemble of random stochastic matrices. For matrices of order N = 2 we derive explicit formulae for the probability distributions induced by random stochastic matrices with columns distributed according to the Dirichlet distribution. For arbitrary N we construct an initial ensemble of stochastic matrices which allows one to generate random bistochastic matrices according to a distribution locally flat at the center of the Birkhoff polytope. The value of the probability density at this point enables us to obtain an estimation of the volume of the Birkhoff polytope, consistent with recent asymptotic results.
Cappellini, V; Bruzda, W; Zyczkowski, K
2009-01-01
Ensembles of random stochastic and bistochastic matrices are investigated. While all columns of a random stochastic matrix can be chosen independently, the rows and columns of a bistochastic matrix have to be correlated. We evaluate the probability measure induced into the Birkhoff polytope of bistochastic matrices by applying the Sinkhorn algorithm to a given ensemble of random stochastic matrices. For matrices of order N=2 we derive explicit formulae for the probability distributions induced by random stochastic matrices with columns distributed according to the Dirichlet distribution. For arbitrary $N$ we construct an initial ensemble of stochastic matrices which allows one to generate random bistochastic matrices according to a distribution locally flat at the center of the Birkhoff polytope. The value of the probability density at this point enables us to obtain an estimation of the volume of the Birkhoff polytope, consistent with recent asymptotic results.
Complex Hadamard matrices from Sylvester inverse orthogonal matrices
Dita, Petre
2009-01-01
A novel method to obtain parametrizations of complex inverse orthogonal matrices is provided. These matrices are natural generalizations of complex Hadamard matrices which depend on non zero complex parameters. The method we use is via doubling the size of inverse complex conference matrices. When the free parameters take values on the unit circle the inverse orthogonal matrices transform into complex Hadamard matrices, and in this way we find new parametrizations of Hadamard matrices for dim...
Matrices and linear transformations
Cullen, Charles G
1990-01-01
""Comprehensive . . . an excellent introduction to the subject."" - Electronic Engineer's Design Magazine.This introductory textbook, aimed at sophomore- and junior-level undergraduates in mathematics, engineering, and the physical sciences, offers a smooth, in-depth treatment of linear algebra and matrix theory. The major objects of study are matrices over an arbitrary field. Contents include Matrices and Linear Systems; Vector Spaces; Determinants; Linear Transformations; Similarity: Part I and Part II; Polynomials and Polynomial Matrices; Matrix Analysis; and Numerical Methods. The first
A Simple Cocyclic Jacket Matrices
Directory of Open Access Journals (Sweden)
Moon Ho Lee
2008-01-01
Full Text Available We present a new class of cocyclic Jacket matrices over complex number field with any size. We also construct cocyclic Jacket matrices over the finite field. Such kind of matrices has close relation with unitary matrices which are a first hand tool in solving many problems in mathematical and theoretical physics. Based on the analysis of the relation between cocyclic Jacket matrices and unitary matrices, the common method for factorizing these two kinds of matrices is presented.
La sensibilité potentielle du sol à l’érosion hydrique dans l’ouest de la Bekaa au Liban
Directory of Open Access Journals (Sweden)
Hussein El Hage Hassan
2013-06-01
Full Text Available Cet article étudie la sensibilité potentielle du sol à l'érosion hydrique, dans la Bekaa Ouest, à partir d'une approche qualitative qui permet de croiser, à l'aide d'un SIG, les données telles que: l'érodibilité et la battance du sol, le gradient de la pente et l'influence du couvert du sol à l'érosion. Le résultat de la cartographie identifie les secteurs menacés par l'érosion hydrique afin de les protéger. Les trois quarts du secteur étudié ont une sensibilité forte ou très forte. Il s'agit ici de montrer une méthode qui peut être appliquée à d'autres terrains.
On greedy and submodular matrices
Faigle, U.; Kern, Walter; Peis, Britta; Marchetti-Spaccamela, Alberto; Segal, Michael
2011-01-01
We characterize non-negative greedy matrices, i.e., 0-1 matrices $A$ such that max $\\{c^Tx|Ax \\le b,\\,x \\ge 0\\}$ can be solved greedily. We identify submodular matrices as a special subclass of greedy matrices. Finally, we extend the notion of greediness to $\\{-1,0,+1\\}$-matrices. We present
Gaussian Fibonacci Circulant Type Matrices
Directory of Open Access Journals (Sweden)
Zhaolin Jiang
2014-01-01
Full Text Available Circulant matrices have become important tools in solving integrable system, Hamiltonian structure, and integral equations. In this paper, we prove that Gaussian Fibonacci circulant type matrices are invertible matrices for n>2 and give the explicit determinants and the inverse matrices. Furthermore, the upper bounds for the spread on Gaussian Fibonacci circulant and left circulant matrices are presented, respectively.
Justino, Júlia
2017-06-01
Matrices with coefficients having uncertainties of type o (.) or O (.), called flexible matrices, are studied from the point of view of nonstandard analysis. The uncertainties of the afore-mentioned kind will be given in the form of the so-called neutrices, for instance the set of all infinitesimals. Since flexible matrices have uncertainties in their coefficients, it is not possible to define the identity matrix in an unique way and so the notion of spectral identity matrix arises. Not all nonsingular flexible matrices can be turned into a spectral identity matrix using Gauss-Jordan elimination method, implying that that not all nonsingular flexible matrices have the inverse matrix. Under certain conditions upon the size of the uncertainties appearing in a nonsingular flexible matrix, a general theorem concerning the boundaries of its minors is presented which guarantees the existence of the inverse matrix of a nonsingular flexible matrix.
On the tensor Permutation Matrices
Rakotonirina, Christian
2011-01-01
A property that tensor permutation matrices permutate tensor product of rectangle matrices is shown. Some examples, in the particular case of tensor commutation matrices, for studying some linear matricial equations are given.
DEFF Research Database (Denmark)
Britz, Thomas
Bipartite graphs and digraphs are used to describe algebraic operations on a free matrix, including Moore-Penrose inversion, finding Schur complements, and normalized LU factorization. A description of the structural properties of a free matrix and its Moore-Penrose inverse is proved, and necessa...... and sufficient conditions are given for the Moore-Penrose inverse of a free matrix to be free. Several of these results are generalized with respect to a family of matrices that contains both the free matrices and the nearly reducible matrices....
DEFF Research Database (Denmark)
Britz, Thomas
Bipartite graphs and digraphs are used to describe algebraic operations on a free matrix, including Moore-Penrose inversion, finding Schur complements, and normalized LU factorization. A description of the structural properties of a free matrix and its Moore-Penrose inverse is proved, and necessa...... and sufficient conditions are given for the Moore-Penrose inverse of a free matrix to be free. Several of these results are generalized with respect to a family of matrices that contains both the free matrices and the nearly reducible matrices....
Indian Academy of Sciences (India)
Narendra Singh
2003-01-01
Assuming a relation between the quark mass matrices of the two sectors a unique solution can be obtained for the CKM ﬂavor mixing matrix. A numerical example is worked out which is in excellent agreement with experimental data.
Matrices in Engineering Problems
Tobias, Marvin
2011-01-01
This book is intended as an undergraduate text introducing matrix methods as they relate to engineering problems. It begins with the fundamentals of mathematics of matrices and determinants. Matrix inversion is discussed, with an introduction of the well known reduction methods. Equation sets are viewed as vector transformations, and the conditions of their solvability are explored. Orthogonal matrices are introduced with examples showing application to many problems requiring three dimensional thinking. The angular velocity matrix is shown to emerge from the differentiation of the 3-D orthogo
Infinite matrices and sequence spaces
Cooke, Richard G
2014-01-01
This clear and correct summation of basic results from a specialized field focuses on the behavior of infinite matrices in general, rather than on properties of special matrices. Three introductory chapters guide students to the manipulation of infinite matrices, covering definitions and preliminary ideas, reciprocals of infinite matrices, and linear equations involving infinite matrices.From the fourth chapter onward, the author treats the application of infinite matrices to the summability of divergent sequences and series from various points of view. Topics include consistency, mutual consi
Introduction to matrices and vectors
Schwartz, Jacob T
2001-01-01
In this concise undergraduate text, the first three chapters present the basics of matrices - in later chapters the author shows how to use vectors and matrices to solve systems of linear equations. 1961 edition.
Paraunitary matrices and group rings
Directory of Open Access Journals (Sweden)
Barry Hurley
2014-03-01
Full Text Available Design methods for paraunitary matrices from complete orthogonal sets of idempotents and related matrix structuresare presented. These include techniques for designing non-separable multidimensional paraunitary matrices. Properties of the structures are obtained and proofs given. Paraunitary matrices play a central role in signal processing, inparticular in the areas of filterbanks and wavelets.
Domcke, Valerie
2016-01-01
We study natural lepton mass matrices, obtained assuming the stability of physical flavour observables with respect to the variations of individual matrix elements. We identify all four possible stable neutrino textures from algebraic conditions on their entries. Two of them turn out to be uniquely associated to specific neutrino mass patterns. We then concentrate on the semi-degenerate pattern, corresponding to an overall neutrino mass scale within the reach of future experiments. In this context we show that i) the neutrino and charged lepton mixings and mass matrices are largely constrained by the requirement of stability, ii) naturalness considerations give a mild preference for the Majorana phase most relevant for neutrinoless double-beta decay, $\\alpha \\sim \\pi/2$, and iii) SU(5) unification allows to extend the implications of stability to the down quark sector. The above considerations would benefit from an experimental determination of the PMNS ratio $|U_{32}/U_{31}|$, i.e. of the Dirac phase $\\delta...
Bapat, Ravindra B
2014-01-01
This new edition illustrates the power of linear algebra in the study of graphs. The emphasis on matrix techniques is greater than in other texts on algebraic graph theory. Important matrices associated with graphs (for example, incidence, adjacency and Laplacian matrices) are treated in detail. Presenting a useful overview of selected topics in algebraic graph theory, early chapters of the text focus on regular graphs, algebraic connectivity, the distance matrix of a tree, and its generalized version for arbitrary graphs, known as the resistance matrix. Coverage of later topics include Laplacian eigenvalues of threshold graphs, the positive definite completion problem and matrix games based on a graph. Such an extensive coverage of the subject area provides a welcome prompt for further exploration. The inclusion of exercises enables practical learning throughout the book. In the new edition, a new chapter is added on the line graph of a tree, while some results in Chapter 6 on Perron-Frobenius theory are reo...
Gil, José J; José, Ignacio San
2015-01-01
Singular Mueller matrices play an important role in polarization algebra and have peculiar properties that stem from the fact that either the medium exhibits maximum diattenuation and/or polarizance, or because its associated canonical depolarizer has the property of fully randomizing, the circular component (at least) of the states of polarization of light incident on it. The formal reasons for which the Mueller matrix M of a given medium is singular are systematically investigated, analyzed and interpreted in the framework of the serial decompositions and the characteristic ellipsoids of M. The analysis allows for a general classification and geometric representation of singular Mueller matrices, of potential usefulness to experimentalists dealing with such media.
Nanoceramic Matrices: Biomedical Applications
Directory of Open Access Journals (Sweden)
Willi Paul
2006-01-01
Full Text Available Natural bone consisted of calcium phosphate with nanometer-sized needle-like crystals of approximately 5-20 nm width by 60 nm length. Synthetic calcium phosphates and Bioglass are biocompatible and bioactive as they bond to bone and enhance bone tissue formation. This property is attributed to their similarity with the mineral phase of natural bone except its constituent particle size. Calcium phosphate ceramics have been used in dentistry and orthopedics for over 30 years because of these properties. Several studies indicated that incorporation of growth hormones into these ceramic matrices facilitated increased tissue regeneration. Nanophase calcium phosphates can mimic the dimensions of constituent components of natural tissues; can modulate enhanced osteoblast adhesion and resorption with long-term functionality of tissue engineered implants. This mini review discusses some of the recent developments in nanophase ceramic matrices utilized for bone tissue engineering.
On Random Correlation Matrices
1988-10-28
the spectral features of the resulting matrices are unknown. Method 2: Perturbation about a Mean This method is discussed by Marsaglia and Okin,10...complete regressor set. Finally, Marsaglia and Olkin (1984, Reference 10) give a rigorous mathematical description of Methods 2 through 4 described in the...short paper by Marsaglia 46 has a review of these early contributions, along with an improved method. More recent references are the pragmatic paper
Concentration for noncommutative polynomials in random matrices
2011-01-01
We present a concentration inequality for linear functionals of noncommutative polynomials in random matrices. Our hypotheses cover most standard ensembles, including Gaussian matrices, matrices with independent uniformly bounded entries and unitary or orthogonal matrices.
Schneider, Hans
1989-01-01
Linear algebra is one of the central disciplines in mathematics. A student of pure mathematics must know linear algebra if he is to continue with modern algebra or functional analysis. Much of the mathematics now taught to engineers and physicists requires it.This well-known and highly regarded text makes the subject accessible to undergraduates with little mathematical experience. Written mainly for students in physics, engineering, economics, and other fields outside mathematics, the book gives the theory of matrices and applications to systems of linear equations, as well as many related t
Universality of Covariance Matrices
Pillai, Natesh S
2011-01-01
We prove the universality of covariance matrices of the form $H_{N \\times N} = {1 \\over N} \\tp{X}X$ where $[X]_{M \\times N}$ is a rectangular matrix with independent real valued entries $[x_{ij}]$ satisfying $\\E \\,x_{ij} = 0$ and $\\E \\,x^2_{ij} = {1 \\over M}$, $N, M\\to \\infty$. Furthermore it is assumed that these entries have sub-exponential tails. We will study the asymptotics in the regime $N/M = d_N \\in (0,\\infty), \\lim_{N\\to \\infty}d_N \
M Wedderburn, J H
1934-01-01
It is the organization and presentation of the material, however, which make the peculiar appeal of the book. This is no mere compendium of results-the subject has been completely reworked and the proofs recast with the skill and elegance which come only from years of devotion. -Bulletin of the American Mathematical Society The very clear and simple presentation gives the reader easy access to the more difficult parts of the theory. -Jahrbuch über die Fortschritte der Mathematik In 1937, the theory of matrices was seventy-five years old. However, many results had only recently evolved from sp
Wognum, P.M.; Bondarouk, Tatiana; Weber, F; Pawar, K.S.; Thoben, K.D.
2003-01-01
The concept of Concurrent Engineering (CE) centers around the management of information so that the right information will be at the right place at the right time and in the right format. Product Data Management (PDM) aims to support a CE way of working in product development processes. In specific
Truncations of random unitary matrices
Zyczkowski, K; Zyczkowski, Karol; Sommers, Hans-Juergen
1999-01-01
We analyze properties of non-hermitian matrices of size M constructed as square submatrices of unitary (orthogonal) random matrices of size N>M, distributed according to the Haar measure. In this way we define ensembles of random matrices and study the statistical properties of the spectrum located inside the unit circle. In the limit of large matrices, this ensemble is characterized by the ratio M/N. For the truncated CUE we derive analytically the joint density of eigenvalues from which easily all correlation functions are obtained. For N-M fixed and N--> infinity the universal resonance-width distribution with N-M open channels is recovered.
Criteria of the Nonsingular H-Matrices
Institute of Scientific and Technical Information of China (English)
GAO jian; LIU Futi; HUANG Tingzhu
2004-01-01
The nonsingular H-matrices play an important role in the study of the matrix theory and the iterative method of systems of linear equations,etc.It has always been searched how to verify nonsingular H-matrices.In this paper,nonsingular H-matrices is studies by applying diagonally dominant matrices,irreducible diagonally dominant matrices and comparison matrices and several practical criteria for identifying nonsingular H-matrices are obtained.
Generalisations of Fisher Matrices
Directory of Open Access Journals (Sweden)
Alan Heavens
2016-06-01
Full Text Available Fisher matrices play an important role in experimental design and in data analysis. Their primary role is to make predictions for the inference of model parameters—both their errors and covariances. In this short review, I outline a number of extensions to the simple Fisher matrix formalism, covering a number of recent developments in the field. These are: (a situations where the data (in the form of ( x , y pairs have errors in both x and y; (b modifications to parameter inference in the presence of systematic errors, or through fixing the values of some model parameters; (c Derivative Approximation for LIkelihoods (DALI - higher-order expansions of the likelihood surface, going beyond the Gaussian shape approximation; (d extensions of the Fisher-like formalism, to treat model selection problems with Bayesian evidence.
Generalisations of Fisher Matrices
Heavens, Alan
2016-01-01
Fisher matrices play an important role in experimental design and in data analysis. Their primary role is to make predictions for the inference of model parameters - both their errors and covariances. In this short review, I outline a number of extensions to the simple Fisher matrix formalism, covering a number of recent developments in the field. These are: (a) situations where the data (in the form of (x,y) pairs) have errors in both x and y; (b) modifications to parameter inference in the presence of systematic errors, or through fixing the values of some model parameters; (c) Derivative Approximation for LIkelihoods (DALI) - higher-order expansions of the likelihood surface, going beyond the Gaussian shape approximation; (d) extensions of the Fisher-like formalism, to treat model selection problems with Bayesian evidence.
VanderLaan Circulant Type Matrices
Directory of Open Access Journals (Sweden)
Hongyan Pan
2015-01-01
Full Text Available Circulant matrices have become a satisfactory tools in control methods for modern complex systems. In the paper, VanderLaan circulant type matrices are presented, which include VanderLaan circulant, left circulant, and g-circulant matrices. The nonsingularity of these special matrices is discussed by the surprising properties of VanderLaan numbers. The exact determinants of VanderLaan circulant type matrices are given by structuring transformation matrices, determinants of well-known tridiagonal matrices, and tridiagonal-like matrices. The explicit inverse matrices of these special matrices are obtained by structuring transformation matrices, inverses of known tridiagonal matrices, and quasi-tridiagonal matrices. Three kinds of norms and lower bound for the spread of VanderLaan circulant and left circulant matrix are given separately. And we gain the spectral norm of VanderLaan g-circulant matrix.
Polynomial Fibonacci-Hessenberg matrices
Energy Technology Data Exchange (ETDEWEB)
Esmaeili, Morteza [Dept. of Mathematical Sciences, Isfahan University of Technology, 84156-83111 Isfahan (Iran, Islamic Republic of)], E-mail: emorteza@cc.iut.ac.ir; Esmaeili, Mostafa [Dept. of Electrical and Computer Engineering, Isfahan University of Technology, 84156-83111 Isfahan (Iran, Islamic Republic of)
2009-09-15
A Fibonacci-Hessenberg matrix with Fibonacci polynomial determinant is referred to as a polynomial Fibonacci-Hessenberg matrix. Several classes of polynomial Fibonacci-Hessenberg matrices are introduced. The notion of two-dimensional Fibonacci polynomial array is introduced and three classes of polynomial Fibonacci-Hessenberg matrices satisfying this property are given.
Enhancing Understanding of Transformation Matrices
Dick, Jonathan; Childrey, Maria
2012-01-01
With the Common Core State Standards' emphasis on transformations, teachers need a variety of approaches to increase student understanding. Teaching matrix transformations by focusing on row vectors gives students tools to create matrices to perform transformations. This empowerment opens many doors: Students are able to create the matrices for…
Enhancing Understanding of Transformation Matrices
Dick, Jonathan; Childrey, Maria
2012-01-01
With the Common Core State Standards' emphasis on transformations, teachers need a variety of approaches to increase student understanding. Teaching matrix transformations by focusing on row vectors gives students tools to create matrices to perform transformations. This empowerment opens many doors: Students are able to create the matrices for…
Hierarchical matrices algorithms and analysis
Hackbusch, Wolfgang
2015-01-01
This self-contained monograph presents matrix algorithms and their analysis. The new technique enables not only the solution of linear systems but also the approximation of matrix functions, e.g., the matrix exponential. Other applications include the solution of matrix equations, e.g., the Lyapunov or Riccati equation. The required mathematical background can be found in the appendix. The numerical treatment of fully populated large-scale matrices is usually rather costly. However, the technique of hierarchical matrices makes it possible to store matrices and to perform matrix operations approximately with almost linear cost and a controllable degree of approximation error. For important classes of matrices, the computational cost increases only logarithmically with the approximation error. The operations provided include the matrix inversion and LU decomposition. Since large-scale linear algebra problems are standard in scientific computing, the subject of hierarchical matrices is of interest to scientists ...
Estimating sparse precision matrices
Padmanabhan, Nikhil; White, Martin; Zhou, Harrison H.; O'Connell, Ross
2016-08-01
We apply a method recently introduced to the statistical literature to directly estimate the precision matrix from an ensemble of samples drawn from a corresponding Gaussian distribution. Motivated by the observation that cosmological precision matrices are often approximately sparse, the method allows one to exploit this sparsity of the precision matrix to more quickly converge to an asymptotic 1/sqrt{N_sim} rate while simultaneously providing an error model for all of the terms. Such an estimate can be used as the starting point for further regularization efforts which can improve upon the 1/sqrt{N_sim} limit above, and incorporating such additional steps is straightforward within this framework. We demonstrate the technique with toy models and with an example motivated by large-scale structure two-point analysis, showing significant improvements in the rate of convergence. For the large-scale structure example, we find errors on the precision matrix which are factors of 5 smaller than for the sample precision matrix for thousands of simulations or, alternatively, convergence to the same error level with more than an order of magnitude fewer simulations.
Generating random density matrices
Zyczkowski, Karol; Nechita, Ion; Collins, Benoit
2010-01-01
We study various methods to generate ensembles of quantum density matrices of a fixed size N and analyze the corresponding probability distributions P(x), where x denotes the rescaled eigenvalue, x=N\\lambda. Taking a random pure state of a two-partite system and performing the partial trace over one subsystem one obtains a mixed state represented by a Wishart--like matrix W=GG^{\\dagger}, distributed according to the induced measure and characterized asymptotically, as N -> \\infty, by the Marchenko-Pastur distribution. Superposition of k random maximally entangled states leads to another family of explicitly derived distributions, describing singular values of the sum of k independent random unitaries. Taking a larger system composed of 2s particles, constructing $s$ random bi-partite states, performing the measurement into a product of s-1 maximally entangled states and performing the partial trace over the remaining subsystem we arrive at a random state characterized by the Fuss-Catalan distribution of order...
Graph-theoretical matrices in chemistry
Janezic, Dusanka; Nikolic, Sonja; Trinajstic, Nenad
2015-01-01
Graph-Theoretical Matrices in Chemistry presents a systematic survey of graph-theoretical matrices and highlights their potential uses. This comprehensive volume is an updated, extended version of a former bestseller featuring a series of mathematical chemistry monographs. In this edition, nearly 200 graph-theoretical matrices are included.This second edition is organized like the previous one-after an introduction, graph-theoretical matrices are presented in five chapters: The Adjacency Matrix and Related Matrices, Incidence Matrices, The Distance Matrix and Related Matrices, Special Matrices
Hadamard Matrices and Their Applications
Horadam, K J
2011-01-01
In Hadamard Matrices and Their Applications, K. J. Horadam provides the first unified account of cocyclic Hadamard matrices and their applications in signal and data processing. This original work is based on the development of an algebraic link between Hadamard matrices and the cohomology of finite groups that was discovered fifteen years ago. The book translates physical applications into terms a pure mathematician will appreciate, and theoretical structures into ones an applied mathematician, computer scientist, or communications engineer can adapt and use. The first half of the book expl
Bayes linear adjustment for variance matrices
Wilkinson, Darren J
2008-01-01
We examine the problem of covariance belief revision using a geometric approach. We exhibit an inner-product space where covariance matrices live naturally --- a space of random real symmetric matrices. The inner-product on this space captures aspects of our beliefs about the relationship between covariance matrices of interest to us, providing a structure rich enough for us to adjust beliefs about unknown matrices in the light of data such as sample covariance matrices, exploiting second-order exchangeability specifications.
Verhagen, Wim J.C.; Stjepandić, Josip; Wognum, Nel
2015-01-01
Despite a long pedigree and many positive reports on its use and benefits, concurrent engineering (CE) and its associated research (sub)domains still experience significant development. In this final chapter, a socio-technical framework is applied to classify and analyze challenges identified as
DEFF Research Database (Denmark)
Mohamed, Nader; Lazarova-Molnar, Sanja; Al-Jaroodi, Jameela
2016-01-01
and costs savings in smart buildings significantly depend on the monitoring and control methods used in the installed BEMS. This paper proposes a Cloud-Enabled BEMS (CE-BEMS) for Smart Buildings. This system can utilize cloud computing to provide enhanced management mechanisms and features for energy...
Multiplicative equations over commuting matrices
Energy Technology Data Exchange (ETDEWEB)
Babai, L. [Univ. of Chicago, IL (United States)]|[Eotvos Univ., Budapest (Hungary); Beals, R. [Rutgers Univ., Piscataway, NJ (United States); Cai, Jin-Yi [SUNY, Buffalo, NY (United States)] [and others
1996-12-31
We consider the solvability of the equation and generalizations, where the A{sub i} and B are given commuting matrices over an algebraic number field F. In the semigroup membership problem, the variables x{sub i} are constrained to be nonnegative integers. While this problem is NP-complete for variable k, we give a polynomial time algorithm if k is fixed. In the group membership problem, the matrices are assumed to be invertible, and the variables x{sub i} may take on negative values. In this case we give a polynomial time algorithm for variable k and give an explicit description of the set of all solutions (as an affine lattice). The special case of 1 x 1 matrices was recently solved by Guoqiang Ge; we heavily rely on his results.
Free probability and random matrices
Mingo, James A
2017-01-01
This volume opens the world of free probability to a wide variety of readers. From its roots in the theory of operator algebras, free probability has intertwined with non-crossing partitions, random matrices, applications in wireless communications, representation theory of large groups, quantum groups, the invariant subspace problem, large deviations, subfactors, and beyond. This book puts a special emphasis on the relation of free probability to random matrices, but also touches upon the operator algebraic, combinatorial, and analytic aspects of the theory. The book serves as a combination textbook/research monograph, with self-contained chapters, exercises scattered throughout the text, and coverage of important ongoing progress of the theory. It will appeal to graduate students and all mathematicians interested in random matrices and free probability from the point of view of operator algebras, combinatorics, analytic functions, or applications in engineering and statistical physics.
Immanant Conversion on Symmetric Matrices
Directory of Open Access Journals (Sweden)
Purificação Coelho M.
2014-01-01
Full Text Available Letr Σn(C denote the space of all n χ n symmetric matrices over the complex field C. The main objective of this paper is to prove that the maps Φ : Σn(C -> Σn (C satisfying for any fixed irre- ducible characters X, X' -SC the condition dx(A +aB = dχ·(Φ(Α + αΦ(Β for all matrices A,В ε Σ„(С and all scalars a ε C are automatically linear and bijective. As a corollary of the above result we characterize all such maps Φ acting on ΣИ(С.
Iterative methods for Toeplitz-like matrices
Energy Technology Data Exchange (ETDEWEB)
Huckle, T. [Universitaet Wurzburg (Germany)
1994-12-31
In this paper the author will give a survey on iterative methods for solving linear equations with Toeplitz matrices, Block Toeplitz matrices, Toeplitz plus Hankel matrices, and matrices with low displacement rank. He will treat the following subjects: (1) optimal (w)-circulant preconditioners is a generalization of circulant preconditioners; (2) Optimal implementation of circulant-like preconditioners in the complex and real case; (3) preconditioning of near-singular matrices; what kind of preconditioners can be used in this case; (4) circulant preconditioning for more general classes of Toeplitz matrices; what can be said about matrices with coefficients that are not l{sub 1}-sequences; (5) preconditioners for Toeplitz least squares problems, for block Toeplitz matrices, and for Toeplitz plus Hankel matrices.
Sign pattern matrices that admit M-, N-, P- or inverse M-matrices
Araújo, C. Mendes; Torregrosa, Juan R.
2009-01-01
In this paper we identify the sign pattern matrices that occur among the N–matrices, the P–matrices and the M–matrices. We also address to the class of inverse M–matrices and the related admissibility of sign pattern matrices problem. Fundação para a Ciência e a Tecnologia (FCT) Spanish DGI grant number MTM2007-64477
Hamiltonian formalism and symplectic matrices; Formalisme Hamiltonien et Matrices symplectiques
Energy Technology Data Exchange (ETDEWEB)
Bertrand, P. [Project SPIRAL, Grand Accelerateur National d`Ions Lourds, BP 5027, Bd. H. Becquerel, 14076 Caen cedex 5 (France)
1997-12-31
This work consists of five sections. The first one introduces the Lagrangian formalism starting from the fundamental equation of the dynamics. The sections 2 to 4 are devoted to the Hamiltonian formalism and to symplectic matrices. Lie algebra and groups were avoided, although these notions are very useful if higher order effects have to be investigated. The paper is dealing with the properties of the transfer matrices describing different electromagnetic objects like, for instance: dipoles, quadrupoles, cyclotrons, electrostatic deflectors, spiral inflectors, etc. A remarkable property of the first order exact transfer matrices, is the symplecticity which in case of a 3-D object, described in 6-D phase space, provides 15 non-linear equations relating the matrix coefficients. The symplectic matrix ensemble forms an multiplication non-commuting group, consequently the product of n symplectic matrices is still a symplectic matrix. This permits the global description of a system of n objects. Thus, the notion symplecticity is fundamental for the selection of a given electromagnetic object, for its optimization and insertion in a line of beam transfer. The symplectic relations indicate actually that if a given beam characteristic is modified, then another characteristic will be affected and as a result the spurious effects can be limited when a line is to be adjusted. The last section is devoted to the application of the elaborated procedure to describe the drift of non-relativistic and relativistic particles, the dipole and the Muller inflector. Hopefully, this elementary Hamiltonian formalism will help in the familiarization with the symplectic matrices extensively utilized at GANIL 10 refs.
Fractal Structure of Random Matrices
Hussein, M S
2000-01-01
A multifractal analysis is performed on the universality classes of random matrices and the transition ones.Our results indicate that the eigenvector probability distribution is a linear sum of two chi-squared distribution throughout the transition between the universality ensembles of random matrix theory and Poisson .
Open string fields as matrices
Kishimoto, Isao; Masuda, Toru; Takahashi, Tomohiko; Takemoto, Shoko
2015-03-01
We show that the action expanded around Erler-Maccaferri's N D-brane solution describes the N+1 D-brane system where one D-brane disappears due to tachyon condensation. String fields on multi-branes can be regarded as block matrices of a string field on a single D-brane in the same way as matrix theories.
Open String Fields as Matrices
Kishimoto, Isao; Takahashi, Tomohiko; Takemoto, Shoko
2014-01-01
We show that the action expanded around Erler-Maccaferri's N D-branes solution describes the N+1 D-branes system where one D-brane disappears due to tachyon condensation. String fields on the multi-branes can be regarded as block matrices of a string field on a single D-brane in the same way as matrix theories.
Arnold's Projective Plane and -Matrices
Directory of Open Access Journals (Sweden)
K. Uchino
2010-01-01
Full Text Available We will explain Arnold's 2-dimensional (shortly, 2D projective geometry (Arnold, 2005 by means of lattice theory. It will be shown that the projection of the set of nontrivial triangular -matrices is the pencil of tangent lines of a quadratic curve on Arnold's projective plane.
Fibonacci Identities, Matrices, and Graphs
Huang, Danrun
2005-01-01
General strategies used to help discover, prove, and generalize identities for Fibonacci numbers are described along with some properties about the determinants of square matrices. A matrix proof for identity (2) that has received immense attention from many branches of mathematics, like linear algebra, dynamical systems, graph theory and others…
Scattering matrices with block symmetries
Życzkowski, Karol
1997-01-01
Scattering matrices with block symmetry, which corresponds to scattering process on cavities with geometrical symmetry, are analyzed. The distribution of transmission coefficient is computed for different number of channels in the case of a system with or without the time reversal invariance. An interpolating formula for the case of gradual time reversal symmetry breaking is proposed.
Making almost commuting matrices commute
Energy Technology Data Exchange (ETDEWEB)
Hastings, Matthew B [Los Alamos National Laboratory
2008-01-01
Suppose two Hermitian matrices A, B almost commute ({parallel}[A,B]{parallel} {<=} {delta}). Are they close to a commuting pair of Hermitian matrices, A', B', with {parallel}A-A'{parallel},{parallel}B-B'{parallel} {<=} {epsilon}? A theorem of H. Lin shows that this is uniformly true, in that for every {epsilon} > 0 there exists a {delta} > 0, independent of the size N of the matrices, for which almost commuting implies being close to a commuting pair. However, this theorem does not specifiy how {delta} depends on {epsilon}. We give uniform bounds relating {delta} and {epsilon}. The proof is constructive, giving an explicit algorithm to construct A' and B'. We provide tighter bounds in the case of block tridiagonal and tridiagnonal matrices. Within the context of quantum measurement, this implies an algorithm to construct a basis in which we can make a projective measurement that approximately measures two approximately commuting operators simultaneously. Finally, we comment briefly on the case of approximately measuring three or more approximately commuting operators using POVMs (positive operator-valued measures) instead of projective measurements.
Skills Underlying Coloured Progressive Matrices
Kirby, J. R.; Das, J. P.
1978-01-01
Raven's Coloured Progressive Matrices and a battery of ability tests were administered to a sample of 104 male fourth graders for purposes of investigating the relationships between 2 previously identified subscales of the Raven and the ability tests. Results indicated use of a spatial strategy and to a lesser extent, use of reasoning, indicating…
The diagonalization of cubic matrices
Cocolicchio, D.; Viggiano, M.
2000-08-01
This paper is devoted to analysing the problem of the diagonalization of cubic matrices. We extend the familiar algebraic approach which is based on the Cardano formulae. We rewrite the complex roots of the associated resolvent secular equation in terms of transcendental functions and we derive the diagonalizing matrix.
Spectral problems for operator matrices
Bátkai, A.; Binding, P.; Dijksma, A.; Hryniv, R.; Langer, H.
2005-01-01
We study spectral properties of 2 × 2 block operator matrices whose entries are unbounded operators between Banach spaces and with domains consisting of vectors satisfying certain relations between their components. We investigate closability in the product space, essential spectra and generation of
Epitaxial Cubic Ce2O3 Films via Ce-CeO2 Interfacial Reaction.
Stetsovych, Vitalii; Pagliuca, Federico; Dvořák, Filip; Duchoň, Tomáš; Vorokhta, Mykhailo; Aulická, Marie; Lachnitt, Jan; Schernich, Stefan; Matolínová, Iva; Veltruská, Kateřina; Skála, Tomáš; Mazur, Daniel; Mysliveček, Josef; Libuda, Jörg; Matolín, Vladimír
2013-03-21
Thin films of reduced ceria supported on metals are often applied as substrates in model studies of the chemical reactivity of ceria based catalysts. Of special interest are the properties of oxygen vacancies in ceria. However, thin films of ceria prepared by established methods become increasingly disordered as the concentration of vacancies increases. Here, we propose an alternative method for preparing ordered reduced ceria films based on the physical vapor deposition and interfacial reaction of Ce with CeO2 films. The method yields bulk-truncated layers of cubic c-Ce2O3. Compared to CeO2 these layers contain 25% of perfectly ordered vacancies in the surface and subsurface allowing well-defined measurements of the properties of ceria in the limit of extreme reduction. Experimentally, c-Ce2O3(111) layers are easily identified by a characteristic 4 × 4 surface reconstruction with respect to CeO2(111). In addition, c-Ce2O3 layers represent an experimental realization of a normally unstable polymorph of Ce2O3. During interfacial reaction, c-Ce2O3 nucleates on the interface between CeO2 buffer and Ce overlayer and is further stabilized most likely by the tetragonal distortion of the ceria layers on Cu. The characteristic kinetics of the metal-oxide interfacial reactions may represent a vehicle for making other metastable oxide structures experimentally available.
Institute of Scientific and Technical Information of China (English)
张晓东; 杨尚骏
2001-01-01
本文探讨矩阵的一个重要子类（F-矩阵）的性质.F-矩阵包含以下在理论及应用中都很重要的三个矩阵类：对称正半定矩阵，M-矩阵和完全非负矩阵.我们首先证明F-矩阵的一些有趣性，特别是给出n-阶F-矩阵A满足detA=an…ann的充分必要条件.接着研究逆F-矩阵的性质，特别是证明逆M-矩阵和逆完全非负矩阵都是F-矩阵，从而满足Fischer不等式.最后我们引入F-矩阵一个子类:W-矩阵并证明逆W-矩阵也是F-矩阵.%We investigate a class of P0-matrices, called F-matrices, whichcontains well known three important classes of matrices satisfying Hadamard's inequality and Fischer's inequality-positive semidefinite symmetric matrices, M-matrices and totally nonnegative matrices. Firstly we prove some interesting properties of F-matrices and give the necessary and sufficient condition for an n×n F-matrix to satisfy det A=a11…ann. Then we investigate inverse F-matrices and prove both inverse M-matrices and inverse totally nonnegative matrices are F-matrices. Finally we introduce a new class of F-matrices, i.e. W-matrices and prove both W-matrices and inverse W-matrices are also F-matrices.
STABILITY FOR SEVERAL TYPES OF INTERVAL MATRICES
Institute of Scientific and Technical Information of China (English)
NianXiaohong; GaoJintai
1999-01-01
The robust stability for some types of tlme-varying interval raatrices and nonlineartime-varying interval matrices is considered and some sufficient conditions for robust stability of such interval matrices are given, The main results of this paper are only related to the verticesset of a interval matrices, and therefore, can be easily applied to test robust stability of interval matrices. Finally, some examples are given to illustrate the results.
Eigenvalue variance bounds for covariance matrices
Dallaporta, Sandrine
2013-01-01
This work is concerned with finite range bounds on the variance of individual eigenvalues of random covariance matrices, both in the bulk and at the edge of the spectrum. In a preceding paper, the author established analogous results for Wigner matrices and stated the results for covariance matrices. They are proved in the present paper. Relying on the LUE example, which needs to be investigated first, the main bounds are extended to complex covariance matrices by means of the Tao, Vu and Wan...
The Bessel Numbers and Bessel Matrices
Institute of Scientific and Technical Information of China (English)
Sheng Liang YANG; Zhan Ke QIAO
2011-01-01
In this paper,using exponential Riordan arrays,we investigate the Bessel numbers and Bessel matrices.By exploring links between the Bessel matrices,the Stirling matrices and the degenerate Stirling matrices,we show that the Bessel numbers are special case of the degenerate Stirling numbers,and derive explicit formulas for the Bessel numbers in terms of the Stirling numbers and binomial coefficients.
Updating weighting matrices by Cross-Entropy
Directory of Open Access Journals (Sweden)
Esteban Fernández Vázquez
2011-01-01
Full Text Available El enfoque clásico para estimar modelos espaciales parte de la elección de una matriz de pesos espaciales que refleje la interacción entre las diferentes zonas. Se asume que la regla para definir esta matriz es que sea lo más parecida a la «verdadera» red de relaciones espaciales, pero para el investigador es difícil dilucidar cuándo la elección de esta matriz es correcta. Este paso clave en el proceso de estimación de modelos espaciales es una elección arbitraria, como Anselin (2002 señaló, y puede ser visto como uno de sus principales problemas metodológicos. En esta nota se propone no imponer los elementos de la matriz, sino su estimación basándose en la técnica de Entropía Cruzada (CE. Como las matrices de pesos espaciales son frecuentemente normalizadas por filas, cada una de ellas se puede entender como una distribución de probabilidad. La econometría basada en medidas de entropía es una herramienta útil para la obtención de distribuciones de probabilidad desconocidas, y su aplicación permite la estimación de los elementos de la matriz de pesos espaciales. Así, la matriz ya no depende de una elección impuesta por el investigador, sino de una estimación empírica. Este artículo compara los estimadores clásicos con los basados en medidas de entropía por medio de simulaciones de Monte Carlo en varios escenarios. Los resultados muestran que estas estimaciones superan a las obtenidas por estimadores tradicionales, especialmente cuando la especificación de la matriz no es similar a la real. Este resultado destaca la utilidad de las técnicas CE a la hora de reducir el grado de arbitrariedad impuesta en la estimación de modelos espaciales.
Quantum Hilbert matrices and orthogonal polynomials
DEFF Research Database (Denmark)
Andersen, Jørgen Ellegaard; Berg, Christian
2009-01-01
Using the notion of quantum integers associated with a complex number q≠0 , we define the quantum Hilbert matrix and various extensions. They are Hankel matrices corresponding to certain little q -Jacobi polynomials when |q|matrices...... of reciprocal Fibonacci numbers called Filbert matrices. We find a formula for the entries of the inverse quantum Hilbert matrix....
Simultaneous diagonalization of two quaternion matrices
Institute of Scientific and Technical Information of China (English)
ZhouJianhua
2003-01-01
The simultaneous diagonalization by congruence of pairs of Hermitian quatemion matrices is discussed. The problem is reduced to a parallel one on complex matrices by using the complex adjoint matrix related to each quatemion matrix. It is proved that any two semi-positive definite Hermitian quatemion matrices can be simultaneously diagonalized by congruence.
Bombardelli, Diego
2016-08-01
In these notes we review the S-matrix theory in (1+1)-dimensional integrable models, focusing mainly on the relativistic case. Once the main definitions and physical properties are introduced, we discuss the factorization of scattering processes due to integrability. We then focus on the analytic properties of the two-particle scattering amplitude and illustrate the derivation of the S-matrices for all the possible bound states using the so-called bootstrap principle. General algebraic structures underlying the S-matrix theory and its relation with the form factors axioms are briefly mentioned. Finally, we discuss the S-matrices of sine-Gordon and SU(2), SU(3) chiral Gross-Neveu models. In loving memory of Lilia Grandi.
Karger, Barry L; Guttman, András
2009-06-01
Sequencing of human and other genomes has been at the center of interest in the biomedical field over the past several decades and is now leading toward an era of personalized medicine. During this time, DNA-sequencing methods have evolved from the labor-intensive slab gel electrophoresis, through automated multiCE systems using fluorophore labeling with multispectral imaging, to the "next-generation" technologies of cyclic-array, hybridization based, nanopore and single molecule sequencing. Deciphering the genetic blueprint and follow-up confirmatory sequencing of Homo sapiens and other genomes were only possible with the advent of modern sequencing technologies that were a result of step-by-step advances with a contribution of academics, medical personnel and instrument companies. While next-generation sequencing is moving ahead at breakneck speed, the multicapillary electrophoretic systems played an essential role in the sequencing of the Human Genome, the foundation of the field of genomics. In this prospective, we wish to overview the role of CE in DNA sequencing based in part of several of our articles in this journal.
CE microchips: an opened gate to food analysis.
Escarpa, Alberto; González, María Cristina; Crevillén, Agustín González; Blasco, Antonio Javier
2007-03-01
CE microchips are the first generation of micrototal analysis systems (-TAS) emerging in the miniaturization scene of food analysis. CE microchips for food analysis are fabricated in both glass and polymer materials, such as PDMS and poly(methyl methacrylate) (PMMA), and use simple layouts of simple and double T crosses. Nowadays, the detection route preferred is electrochemical in both, amperometry and conductivity modes, using end-channel and contactless configurations, respectively. Food applications using CE microchips are now emerging since food samples present complex matrices, the selectivity being a very important challenge because the total integration of analytical steps into microchip format is very difficult. As a consequence, the first contributions that have recently appeared in the relevant literature are based primarily on fast separations of analytes of high food significance. These protocols are combined with different strategies to achieve selectivity using a suitable nonextensive sample preparation and/or strategically choosing detection routes. Polyphenolic compounds, amino acids, preservatives, and organic and inorganic ions have been studied using CE microchips. Thus, new and exciting future expectations arise in the domain of food analysis. However, several drawbacks could easily be found and assumed within the miniaturization map.
Rotationally invariant ensembles of integrable matrices.
Yuzbashyan, Emil A; Shastry, B Sriram; Scaramazza, Jasen A
2016-05-01
We construct ensembles of random integrable matrices with any prescribed number of nontrivial integrals and formulate integrable matrix theory (IMT)-a counterpart of random matrix theory (RMT) for quantum integrable models. A type-M family of integrable matrices consists of exactly N-M independent commuting N×N matrices linear in a real parameter. We first develop a rotationally invariant parametrization of such matrices, previously only constructed in a preferred basis. For example, an arbitrary choice of a vector and two commuting Hermitian matrices defines a type-1 family and vice versa. Higher types similarly involve a random vector and two matrices. The basis-independent formulation allows us to derive the joint probability density for integrable matrices, similar to the construction of Gaussian ensembles in the RMT.
Rotationally invariant ensembles of integrable matrices
Yuzbashyan, Emil A.; Shastry, B. Sriram; Scaramazza, Jasen A.
2016-05-01
We construct ensembles of random integrable matrices with any prescribed number of nontrivial integrals and formulate integrable matrix theory (IMT)—a counterpart of random matrix theory (RMT) for quantum integrable models. A type-M family of integrable matrices consists of exactly N -M independent commuting N ×N matrices linear in a real parameter. We first develop a rotationally invariant parametrization of such matrices, previously only constructed in a preferred basis. For example, an arbitrary choice of a vector and two commuting Hermitian matrices defines a type-1 family and vice versa. Higher types similarly involve a random vector and two matrices. The basis-independent formulation allows us to derive the joint probability density for integrable matrices, similar to the construction of Gaussian ensembles in the RMT.
CE and nanomaterials - Part II: Nanomaterials in CE.
Adam, Vojtech; Vaculovicova, Marketa
2017-10-01
The scope of this two-part review is to summarize publications dealing with CE and nanomaterials together. This topic can be viewed from two broad perspectives, and this article is trying to highlight these two approaches: (i) CE of nanomaterials, and (ii) nanomaterials in CE. The second part aims at summarization of publications dealing with application of nanomaterials for enhancement of CE performance either in terms of increasing the separation resolution or for improvement of the detection. To increase the resolution, nanomaterials are employed as either surface modification of the capillary wall forming open tubular column or as additives to the separation electrolyte resulting in a pseudostationary phase. Moreover, nanomaterials have proven to be very beneficial for increasing also the sensitivity of detection employed in CE or even they enable the detection (e.g., fluorescent tags of nonfluorescent molecules). © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Feyerherm, R.; Dudzik, E.; Prokeš, K.; Mydosh, J.A.; Huang, Y.K.; Pöttgen, R.
2014-01-01
CeRuSn exhibits an extraordinary room temperature structure at 300 K with the coexistence of two types of Ce ions, namely trivalent Ce3+ and intermediate-valent Ce(4−δ)+, in a metallic environment. The ordered arrangement of these two Ce types on specific crystallographic sites results in a doubling
Projection Matrices, Generalized Inverse Matrices, and Singular Value Decomposition
Yanai, Haruo; Takane, Yoshio
2011-01-01
Aside from distribution theory, projections and the singular value decomposition (SVD) are the two most important concepts for understanding the basic mechanism of multivariate analysis. The former underlies the least squares estimation in regression analysis, which is essentially a projection of one subspace onto another, and the latter underlies principal component analysis, which seeks to find a subspace that captures the largest variability in the original space. This book is about projections and SVD. A thorough discussion of generalized inverse (g-inverse) matrices is also given because
Heavy Fermion Character in Ce2Sb and Ce2Bi
Oyamada, Akira; Isobe, Atsushi; Kitazawa, Hideaki; Ochiai, Akira; Suzuki, Takashi; Kasuya, Tadao
1993-05-01
Magnetic susceptibilities, electrical resistivities and specific heats of Ce2Sb, Ce2Bi and CeLaBi were measured to clarify these physical properties. The most characteristic points of these compounds are the following. Ce site are two dimensional and the distance between Ce atoms are very small. The similarity between these compounds and CeRh3B2, in which Ce sites are one dimensional and the distance between Ce atoms are very small, are discussed.
Random matrices and Riemann hypothesis
Pierre, Christian
2011-01-01
The curious connection between the spacings of the eigenvalues of random matrices and the corresponding spacings of the non trivial zeros of the Riemann zeta function is analyzed on the basis of the geometric dynamical global program of Langlands whose fundamental structures are shifted quantized conjugacy class representatives of bilinear algebraic semigroups.The considered symmetry behind this phenomenology is the differential bilinear Galois semigroup shifting the product,right by left,of automorphism semigroups of cofunctions and functions on compact transcendental quanta.
Sparse Matrices in Frame Theory
DEFF Research Database (Denmark)
Lemvig, Jakob; Krahmer, Felix; Kutyniok, Gitta
2014-01-01
Frame theory is closely intertwined with signal processing through a canon of methodologies for the analysis of signals using (redundant) linear measurements. The canonical dual frame associated with a frame provides a means for reconstruction by a least squares approach, but other dual frames...... yield alternative reconstruction procedures. The novel paradigm of sparsity has recently entered the area of frame theory in various ways. Of those different sparsity perspectives, we will focus on the situations where frames and (not necessarily canonical) dual frames can be written as sparse matrices...
Cosmetic crossings and Seifert matrices
Balm, Cheryl; Kalfagianni, Efstratia; Powell, Mark
2011-01-01
We study cosmetic crossings in knots of genus one and obtain obstructions to such crossings in terms of knot invariants determined by Seifert matrices. In particular, we prove that for genus one knots the Alexander polynomial and the homology of the double cover branching over the knot provide obstructions to cosmetic crossings. As an application we prove the nugatory crossing conjecture for twisted Whitehead doubles of non-cable knots. We also verify the conjecture for several families of pretzel knots and all genus one knots with up to 12 crossings.
Superalgebraic representation of Dirac matrices
Monakhov, V. V.
2016-01-01
We consider a Clifford extension of the Grassmann algebra in which operators are constructed from products of Grassmann variables and derivatives with respect to them. We show that this algebra contains a subalgebra isomorphic to a matrix algebra and that it additionally contains operators of a generalized matrix algebra that mix states with different numbers of Grassmann variables. We show that these operators are extensions of spin-tensors to the case of superspace. We construct a representation of Dirac matrices in the form of operators of a generalized matrix algebra.
Orthogonal polynomials and random matrices
Deift, Percy
2000-01-01
This volume expands on a set of lectures held at the Courant Institute on Riemann-Hilbert problems, orthogonal polynomials, and random matrix theory. The goal of the course was to prove universality for a variety of statistical quantities arising in the theory of random matrix models. The central question was the following: Why do very general ensembles of random n {\\times} n matrices exhibit universal behavior as n {\\rightarrow} {\\infty}? The main ingredient in the proof is the steepest descent method for oscillatory Riemann-Hilbert problems.
Searching for partial Hadamard matrices
Álvarez, Víctor; Frau, María-Dolores; Gudiel, Félix; Güemes, María-Belén; Martín, Elena; Osuna, Amparo
2012-01-01
Three algorithms looking for pretty large partial Hadamard matrices are described. Here "large" means that hopefully about a third of a Hadamard matrix (which is the best asymptotic result known so far, [dLa00]) is achieved. The first one performs some kind of local exhaustive search, and consequently is expensive from the time consuming point of view. The second one comes from the adaptation of the best genetic algorithm known so far searching for cliques in a graph, due to Singh and Gupta [SG06]. The last one consists in another heuristic search, which prioritizes the required processing time better than the final size of the partial Hadamard matrix to be obtained. In all cases, the key idea is characterizing the adjacency properties of vertices in a particular subgraph G_t of Ito's Hadamard Graph Delta (4t) [Ito85], since cliques of order m in G_t can be seen as (m+3)*4t partial Hadamard matrices.
A concise guide to complex Hadamard matrices
Tadej, W; Tadej, Wojciech; Zyczkowski, Karol
2005-01-01
Complex Hadamard matrices, consisting of unimodular entries with arbitrary phases, play an important role in the theory of quantum information. We review basic properties of complex Hadamard matrices and present a catalogue of inequivalent cases known for dimension N=2,...,16. In particular, we explicitly write down some families of complex Hadamard matrices for N=12,14 and 16, which we could not find in the existing literature.
Lambda-matrices and vibrating systems
Lancaster, Peter; Stark, M; Kahane, J P
1966-01-01
Lambda-Matrices and Vibrating Systems presents aspects and solutions to problems concerned with linear vibrating systems with a finite degrees of freedom and the theory of matrices. The book discusses some parts of the theory of matrices that will account for the solutions of the problems. The text starts with an outline of matrix theory, and some theorems are proved. The Jordan canonical form is also applied to understand the structure of square matrices. Classical theorems are discussed further by applying the Jordan canonical form, the Rayleigh quotient, and simple matrix pencils with late
Matrices with totally positive powers and their generalizations
Kushel, Olga Y.
2013-01-01
In this paper, eventually totally positive matrices (i.e. matrices all whose powers starting with some point are totally positive) are studied. We present a new approach to eventual total positivity which is based on the theory of eventually positive matrices. We mainly focus on the spectral properties of such matrices. We also study eventually J-sign-symmetric matrices and matrices, whose powers are P-matrices.
A NOTE ON THE STOCHASTIC ROOTS OF STOCHASTIC MATRICES
Institute of Scientific and Technical Information of China (English)
Qi-Ming HE; Eldon GUNN
2003-01-01
In this paper, we study the stochastic root matrices of stochastic matrices. All stochastic roots of 2×2 stochastic matrices are found explicitly. A method based on characteristic polynomial of matrix is developed to find all real root matrices that are functions of the original 3×3 matrix, including all possible (function) stochastic root matrices. In addition, we comment on some numerical methods for computing stochastic root matrices of stochastic matrices.
Institute of Scientific and Technical Information of China (English)
YANG Lizhen; CHEN Kefei
2004-01-01
In this paper, we analyze the structure of the orders of matrices (mod n), and present the relation between the orders of matrices over finite fields and their Jordan normal forms. Then we generalize 2-dimensional Arnold transformation matrix to two types of n-dimensional Arnold transformation matrices: A-type Arnold transformation matrix and B-type transformation matrix, and analyze their orders and other properties based on our earlier results about the orders of matrices.
The lower bounds for the rank of matrices and some sufficient conditions for nonsingular matrices.
Wang, Dafei; Zhang, Xumei
2017-01-01
The paper mainly discusses the lower bounds for the rank of matrices and sufficient conditions for nonsingular matrices. We first present a new estimation for [Formula: see text] ([Formula: see text] is an eigenvalue of a matrix) by using the partitioned matrices. By using this estimation and inequality theory, the new and more accurate estimations for the lower bounds for the rank are deduced. Furthermore, based on the estimation for the rank, some sufficient conditions for nonsingular matrices are obtained.
A note on "Block H-matrices and spectrum of block matrices"
Institute of Scientific and Technical Information of China (English)
LIU Jian-zhou; HUANG Ze-jun
2008-01-01
In this paper, we make further discussions and improvements on the results presented in the previously published work "Block H-matrices and spectrum of block matrices". Furthermore, a new bound for eigenvalues of block matrices is given with examples to show advantages of the new result.
A partial classification of primes in the positive matrices and in the doubly stochastic matrices
G. Picci; J.M. van den Hof; J.H. van Schuppen (Jan)
1995-01-01
textabstractThe algebraic structure of the set of square positive matrices is that of a semi-ring. The concept of a prime in the positive matrices has been introduced. A few examples of primes in the positive matrices are known but there is no general classification. In this paper a partial
Pathological rate matrices: from primates to pathogens
Directory of Open Access Journals (Sweden)
Knight Rob
2008-12-01
Full Text Available Abstract Background Continuous-time Markov models allow flexible, parametrically succinct descriptions of sequence divergence. Non-reversible forms of these models are more biologically realistic but are challenging to develop. The instantaneous rate matrices defined for these models are typically transformed into substitution probability matrices using a matrix exponentiation algorithm that employs eigendecomposition, but this algorithm has characteristic vulnerabilities that lead to significant errors when a rate matrix possesses certain 'pathological' properties. Here we tested whether pathological rate matrices exist in nature, and consider the suitability of different algorithms to their computation. Results We used concatenated protein coding gene alignments from microbial genomes, primate genomes and independent intron alignments from primate genomes. The Taylor series expansion and eigendecomposition matrix exponentiation algorithms were compared to the less widely employed, but more robust, Padé with scaling and squaring algorithm for nucleotide, dinucleotide, codon and trinucleotide rate matrices. Pathological dinucleotide and trinucleotide matrices were evident in the microbial data set, affecting the eigendecomposition and Taylor algorithms respectively. Even using a conservative estimate of matrix error (occurrence of an invalid probability, both Taylor and eigendecomposition algorithms exhibited substantial error rates: ~100% of all exonic trinucleotide matrices were pathological to the Taylor algorithm while ~10% of codon positions 1 and 2 dinucleotide matrices and intronic trinucleotide matrices, and ~30% of codon matrices were pathological to eigendecomposition. The majority of Taylor algorithm errors derived from occurrence of multiple unobserved states. A small number of negative probabilities were detected from the Pad�� algorithm on trinucleotide matrices that were attributable to machine precision. Although the Pad
Institute of Scientific and Technical Information of China (English)
LIU Ying; WU Xiao-Guang; ZHU Li-Hua; LI Guang-Sheng; HE Chuang-Ye; LI Xue-Qin; PAN Bo; HAO Xin; LI Li-Hua; WANG Zhi-Min; LI Zhong-Yu; XU Qiang
2009-01-01
The high spin states of 129Ce have been populated via heavy-ion fusion evaporation reaction 96Mo (37C1, 1p3n) 129Ce. The γ-γ coincidence and intensity balance used to measure the B(M1; I→I-1)/B(E2; I→I-2) (the probability ratio of the dipole and quadrupole transition) in v7/2[523] rotational band of 129Ce. And the energy splitting (Δe') has been got through the experimental Routhians. The lifetimes and quadrupole moments Qt have been extracted from the lineshape analyses using DSAM. The deformation of the v7/2[523] rotational band of 129Ce was extracted from the Qt and moment of inertia JRR.
A review of inversion techniques related to the use of relationship matrices in animal breeding
Directory of Open Access Journals (Sweden)
Faux, P.
2014-01-01
Full Text Available Synthèse bibliographique des techniques d'inversion impliquées dans l'utilisation de matrices de parenté en amélioration animale. En amélioration animale, les effets génétiques sont habituellement prédits par l'utilisation de modèles mixtes. Pour n'importe quel effet génétique, les modèles mixtes nécessitent l'inversion de la matrice de covariance associée à cet effet. Cette matrice est égale à la matrice de parenté associée, multipliée par le composant de la variance génétique également associé à cet effet. Etant donné la taille de nombreux systèmes d'évaluations génétiques, établir l'inverse de ces matrices de parenté peut s'avérer couteux d'un point de vue computationnel. Dans cette synthèse bibliographique, notre objectif est de passer en revue les techniques qui facilitent l'inversion de matrices de parenté utilisée en amélioration animale pour la prédiction des types d'effets génétiques suivants : effet additif, effet gamétique, effet dû à la présence de loci marqués de caractères quantitatifs, effet de dominance et différent effet d'épistasie. Les règles de construction de la matrice et les algorithmes d'inversion sont détaillés pour chaque matrice de parenté. Dans la discussion finale, nous esquissons un cadre théorique commun à la plupart des techniques d'inversion passées en revue. Deux contraintes computationnelles ressortent de ce cadre théorique : l'établissement de la matrice de dépendances entre niveaux de l'effet et celui de certaines parties (diagonales ou bloc-diagonales de la matrice de parenté à inverser.
Dynamical invariance for random matrices
Unterberger, Jeremie
2016-01-01
We consider a general Langevin dynamics for the one-dimensional N-particle Coulomb gas with confining potential $V$ at temperature $\\beta$. These dynamics describe for $\\beta=2$ the time evolution of the eigenvalues of $N\\times N$ random Hermitian matrices. The equilibrium partition function -- equal to the normalization constant of the Laughlin wave function in fractional quantum Hall effect -- is known to satisfy an infinite number of constraints called Virasoro or loop constraints. We introduce here a dynamical generating function on the space of random trajectories which satisfies a large class of constraints of geometric origin. We focus in this article on a subclass induced by the invariance under the Schr\\"odinger-Virasoro algebra.
Tensor Products of Random Unitary Matrices
Tkocz, Tomasz; Kus, Marek; Zeitouni, Ofer; Zyczkowski, Karol
2012-01-01
Tensor products of M random unitary matrices of size N from the circular unitary ensemble are investigated. We show that the spectral statistics of the tensor product of random matrices becomes Poissonian if M=2, N become large or M become large and N=2.
Products of Generalized Stochastic Sarymsakov Matrices
Xia, Weiguo; Liu, Ji; Cao, Ming; Johansson, Karl; Basar, Tamer
2015-01-01
In the set of stochastic, indecomposable, aperiodic (SIA) matrices, the class of stochastic Sarymsakov matrices is the largest known subset (i) that is closed under matrix multiplication and (ii) the inﬁnitely long left-product of the elements from a compact subset converges to a rank-one matrix. In
Kato, T.; Kataoka, J.; Nakamori, T.; Miura, T.; Matsuda, H.; Kishimoto, A.; Sato, K.; Ishikawa, Y.; Yamamura, K.; Nakamura, S.; Kawabata, N.; Ikeda, H.; Yamamoto, S.; Kamada, K.
2013-01-01
We have developed a large-area monolithic Multi-Pixel Photon Counter (MPPC) array consisting of 4×4 channels with a three-side buttable package. Each channel has a photosensitive area of 3×3 mm2 and 3600 Geiger mode avalanche photodiodes (APDs). For typical operational gain of 7.5×105 at +20 °C, gain fluctuation over the entire MPPC device is only ±5.6%, and dark count rates (as measured at the 1 p.e. level) amount to ≤400 kcps per channel. We first fabricated a gamma-ray camera consisting of the MPPC array with one-to-one coupling to a Ce-doped (Lu, Y)2(SiO4)O (Ce:LYSO) crystal array (4×4 array of 3×3×10 mm3 crystals). Energy and time resolutions of 11.5±0.5% (FWHM at 662 keV) and 493±22 ps were obtained, respectively. When using the charge division resistor network, which compiles signals into four position-encoded analog outputs, the ultimate positional resolution is estimated as 0.19 mm in both X and Y directions, while energy resolution of 10.2±0.4% (FWHM) was obtained. Finally, we fabricated submillimeter Ce:LYSO and Ce-doped Gd3Ga3Al2O12 (Ce:GGAG) scintillator matrices each consisting of 1.0×1.0, 0.7×0.7 and 0.5×0.5 mm2 pixels, to further improve the spatial resolution. In all types of Ce:LYSO and Ce:GGAG matrices, each crystal was clearly resolved in the position histograms when irradiated by a 137Cs source. The energy resolutions for 662 keV gamma-rays for each Ce:LYSO and Ce:GGAG scintillator matrix were ≤14.3%. These results suggest excellent potential for its use as a high spatial medical imaging device, particularly in positron emission tomography (PET).
Abel-Grassmann's Groupoids of Modulo Matrices
Directory of Open Access Journals (Sweden)
Muhammad Rashad
2016-01-01
Full Text Available The binary operation of usual addition is associative in all matrices over R. However, a binary operation of addition in matrices over Z n of a nonassociative structures of AG-groupoids and AG-groups are defined and investigated here. It is shown that both these structures exist for every integer n > 3. Various properties of these structures are explored like: (i Every AG-groupoid of matrices over Z n is transitively commutative AG-groupoid and is a cancellative AG-groupoid ifn is prime. (ii Every AG-groupoid of matrices over Z n of Type-II is a T3-AG-groupoid. (iii An AG-groupoid of matrices over Z n ; G nAG(t,u, is an AG-band, ift+ u=1(mod n.
Synthesis and Luminescent Properties of Ce3+, Tb3+ Co-Doped Zn4B6O13
Institute of Scientific and Technical Information of China (English)
常树岚; 李善兰; 阚玉和; 王思宏
2002-01-01
Green-photoluminescence material Zn4B6O13: Ce3+, Tb3+ was first synthesized by spread method of high temperature and solid state reaction, which is cubic crystal system with lattice parameters: a0=0.7472 nm,V=0.4172 nm3, and structural properties are investigated by XRD. The excitation and emission band of Ce3+ ion single-doped in Zn4B6O13 transfer longer spectra 2.38～4.94 kk than in other matrices. Emission band of Ce3+ ion better overlaps with the 7F6→5G2,5D1,5H7 absorption band of Tb3+. It shows that emission of Tb3+ ion is sensitized by Ce3+. In Zn4B6O13∶Ce3+, Tb3+, it is due to the energy transfer mechanism, resonance transfer of electric multipolar interaction of the dipole-dipole between Ce3+→Ce3+ and Ce3+→Tb3+. The color coordinates of Zn4B6O13: x=0.281, y=0.619. The mean diameter of the particles is 0.23 μm.
On Decompositions of Matrices over Distributive Lattices
Directory of Open Access Journals (Sweden)
Yizhi Chen
2014-01-01
Full Text Available Let L be a distributive lattice and Mn,q (L(Mn(L, resp. the semigroup (semiring, resp. of n × q (n × n, resp. matrices over L. In this paper, we show that if there is a subdirect embedding from distributive lattice L to the direct product ∏i=1mLi of distributive lattices L1,L2, …,Lm, then there will be a corresponding subdirect embedding from the matrix semigroup Mn,q(L (semiring Mn(L, resp. to semigroup ∏i=1mMn,q(Li (semiring ∏i=1mMn(Li, resp.. Further, it is proved that a matrix over a distributive lattice can be decomposed into the sum of matrices over some of its special subchains. This generalizes and extends the decomposition theorems of matrices over finite distributive lattices, chain semirings, fuzzy semirings, and so forth. Finally, as some applications, we present a method to calculate the indices and periods of the matrices over a distributive lattice and characterize the structures of idempotent and nilpotent matrices over it. We translate the characterizations of idempotent and nilpotent matrices over a distributive lattice into the corresponding ones of the binary Boolean cases, which also generalize the corresponding structures of idempotent and nilpotent matrices over general Boolean algebras, chain semirings, fuzzy semirings, and so forth.
Compressed Adjacency Matrices: Untangling Gene Regulatory Networks.
Dinkla, K; Westenberg, M A; van Wijk, J J
2012-12-01
We present a novel technique-Compressed Adjacency Matrices-for visualizing gene regulatory networks. These directed networks have strong structural characteristics: out-degrees with a scale-free distribution, in-degrees bound by a low maximum, and few and small cycles. Standard visualization techniques, such as node-link diagrams and adjacency matrices, are impeded by these network characteristics. The scale-free distribution of out-degrees causes a high number of intersecting edges in node-link diagrams. Adjacency matrices become space-inefficient due to the low in-degrees and the resulting sparse network. Compressed adjacency matrices, however, exploit these structural characteristics. By cutting open and rearranging an adjacency matrix, we achieve a compact and neatly-arranged visualization. Compressed adjacency matrices allow for easy detection of subnetworks with a specific structure, so-called motifs, which provide important knowledge about gene regulatory networks to domain experts. We summarize motifs commonly referred to in the literature, and relate them to network analysis tasks common to the visualization domain. We show that a user can easily find the important motifs in compressed adjacency matrices, and that this is hard in standard adjacency matrix and node-link diagrams. We also demonstrate that interaction techniques for standard adjacency matrices can be used for our compressed variant. These techniques include rearrangement clustering, highlighting, and filtering.
Directory of Open Access Journals (Sweden)
Marina Arav
2009-01-01
Full Text Available Let H be an m×n real matrix and let Zi be the set of column indices of the zero entries of row i of H. Then the conditions |Zk∩(∪i=1k−1Zi|≤1 for all k (2≤k≤m are called the (row Zero Position Conditions (ZPCs. If H satisfies the ZPC, then H is said to be a (row ZPC matrix. If HT satisfies the ZPC, then H is said to be a column ZPC matrix. The real matrix H is said to have a zero cycle if H has a sequence of at least four zero entries of the form hi1j1,hi1j2,hi2j2,hi2j3,…,hikjk,hikj1 in which the consecutive entries alternatively share the same row or column index (but not both, and the last entry has one common index with the first entry. Several connections between the ZPC and the nonexistence of zero cycles are established. In particular, it is proved that a matrix H has no zero cycle if and only if there are permutation matrices P and Q such that PHQ is a row ZPC matrix and a column ZPC matrix.
Determination of Strong Acidic Drugs in Biological Matrices: A Review of Separation Methods
Directory of Open Access Journals (Sweden)
Lingli Mu
2014-01-01
Full Text Available Strong acidic drugs are a class of chemical compounds that normally have high hydrophilicity and large negative charges, such as organophosphatic compounds and organosulphonic compounds. This review focuses on sample preparation and separation methods for this group of compounds in biological matrices in recent years. A wide range of separation techniques, especially chromatographic method, are presented and critically discussed, which include liquid chromatography (e.g., ion-pair and ion-exchange chromatography, capillary electrophoresis (CE, and other types. Due to the extremely low concentration level of target analytes as well as the complexity of biological matrices, sample pretreatment methods, such as dilute and shoot methods, protein precipitation (PP, liquid-liquid extraction (LLE, solid-phase extraction (SPE, degradation, and derivatization strategy, also play important roles for the development of successful analytical methods and thus are also discussed.
Random Matrices and Lyapunov Coefficients Regularity
Gallavotti, Giovanni
2017-02-01
Analyticity and other properties of the largest or smallest Lyapunov exponent of a product of real matrices with a "cone property" are studied as functions of the matrices entries, as long as they vary without destroying the cone property. The result is applied to stability directions, Lyapunov coefficients and Lyapunov exponents of a class of products of random matrices and to dynamical systems. The results are not new and the method is the main point of this work: it is is based on the classical theory of the Mayer series in Statistical Mechanics of rarefied gases.
Statistical properties of random density matrices
Sommers, H J; Sommers, Hans-Juergen; Zyczkowski, Karol
2004-01-01
Statistical properties of ensembles of random density matrices are investigated. We compute traces and von Neumann entropies averaged over ensembles of random density matrices distributed according to the Bures measure. The eigenvalues of the random density matrices are analyzed: we derive the eigenvalue distribution for the Bures ensemble which is shown to be broader then the quarter--circle distribution characteristic of the Hilbert--Schmidt ensemble. For measures induced by partial tracing over the environment we compute exactly the two-point eigenvalue correlation function.
Statistical properties of random density matrices
Energy Technology Data Exchange (ETDEWEB)
Sommers, Hans-Juergen [Fachbereich Physik, Universitaet Duisburg-Essen, Campus Essen, 45117 Essen (Germany); Zyczkowski, Karol [Instytut Fizyki im. Smoluchowskiego, Uniwersytet Jagiellonski, ul. Reymonta 4, 30-059 Cracow (Poland)
2004-09-03
Statistical properties of ensembles of random density matrices are investigated. We compute traces and von Neumann entropies averaged over ensembles of random density matrices distributed according to the Bures measure. The eigenvalues of the random density matrices are analysed: we derive the eigenvalue distribution for the Bures ensemble which is shown to be broader then the quarter-circle distribution characteristic of the Hilbert-Schmidt ensemble. For measures induced by partial tracing over the environment we compute exactly the two-point eigenvalue correlation function.
Direct dialling of Haar random unitary matrices
Russell, Nicholas J.; Chakhmakhchyan, Levon; O’Brien, Jeremy L.; Laing, Anthony
2017-03-01
Random unitary matrices find a number of applications in quantum information science, and are central to the recently defined boson sampling algorithm for photons in linear optics. We describe an operationally simple method to directly implement Haar random unitary matrices in optical circuits, with no requirement for prior or explicit matrix calculations. Our physically motivated and compact representation directly maps independent probability density functions for parameters in Haar random unitary matrices, to optical circuit components. We go on to extend the results to the case of random unitaries for qubits.
A method for generating realistic correlation matrices
Garcia, Stephan Ramon
2011-01-01
Simulating sample correlation matrices is important in many areas of statistics. Approaches such as generating normal data and finding their sample correlation matrix or generating random uniform $[-1,1]$ deviates as pairwise correlations both have drawbacks. We develop an algorithm for adding noise, in a highly controlled manner, to general correlation matrices. In many instances, our method yields results which are superior to those obtained by simply simulating normal data. Moreover, we demonstrate how our general algorithm can be tailored to a number of different correlation models. Finally, using our results with an existing clustering algorithm, we show that simulating correlation matrices can help assess statistical methodology.
The Antitriangular Factorization of Saddle Point Matrices
Pestana, J.
2014-01-01
Mastronardi and Van Dooren [SIAM J. Matrix Anal. Appl., 34 (2013), pp. 173-196] recently introduced the block antitriangular ("Batman") decomposition for symmetric indefinite matrices. Here we show the simplification of this factorization for saddle point matrices and demonstrate how it represents the common nullspace method. We show that rank-1 updates to the saddle point matrix can be easily incorporated into the factorization and give bounds on the eigenvalues of matrices important in saddle point theory. We show the relation of this factorization to constraint preconditioning and how it transforms but preserves the structure of block diagonal and block triangular preconditioners. © 2014 Society for Industrial and Applied Mathematics.
RESONANT PHOTOEMISSION OF BULK CeO2 AND NANO—CeO2 FILMS
Institute of Scientific and Technical Information of China (English)
M.I.Abbas; K.Ibrahim; Z.Y.Wu; J.Zhang; F.Q.Liu; H.J.Qian
2001-01-01
Photoemission behaviors of nano-CeO2 films with parlicle sizes ranging from 8nm to 50nm and bulk CeO2 in Ce 4d-4f absorption region have been investigated.Resonant enhancements of Ce 4f valance band and Ce 5p bands for nano film and bulk material have been observed.The variation of electron density of Ce 4d-4f resonace.
Magnetic properties of the Ce-Rh binary phases
Energy Technology Data Exchange (ETDEWEB)
Kappler, J.P.; Lehmann, P.; Schmerber, G. (Strasbourg-1 Univ., 67 (FR). Groupe d' Etude des Materiaux Metalliques); Nieva, G.; Sereni, J.G. (Comision Nacional de Energia Atomica, San Carlos de Bariloche (AR). Centro Atomico Bariloche)
1988-12-01
Crystallographic, magnetic and resistivity studies on the Ce-Rh binary phases clearly define two Ce ground state regions: (i) CeRh{sub 3}, CeRh{sub 2} and CeRh as intermediate valence compounds and (ii) Ce{sub 5}Rh{sub 4}, Ce{sub 3}Rh{sub 2} Ce{sub 5}Rh{sub 3} and Ce{sub 7}Rh{sub 3} with magnetic transitions at low temperature.
Synchronous correlation matrices and Connes’ embedding conjecture
Energy Technology Data Exchange (ETDEWEB)
Dykema, Kenneth J., E-mail: kdykema@math.tamu.edu [Department of Mathematics, Texas A& M University, College Station, Texas 77843-3368 (United States); Paulsen, Vern, E-mail: vern@math.uh.edu [Department of Mathematics, University of Houston, Houston, Texas 77204 (United States)
2016-01-15
In the work of Paulsen et al. [J. Funct. Anal. (in press); preprint arXiv:1407.6918], the concept of synchronous quantum correlation matrices was introduced and these were shown to correspond to traces on certain C*-algebras. In particular, synchronous correlation matrices arose in their study of various versions of quantum chromatic numbers of graphs and other quantum versions of graph theoretic parameters. In this paper, we develop these ideas further, focusing on the relations between synchronous correlation matrices and microstates. We prove that Connes’ embedding conjecture is equivalent to the equality of two families of synchronous quantum correlation matrices. We prove that if Connes’ embedding conjecture has a positive answer, then the tracial rank and projective rank are equal for every graph. We then apply these results to more general non-local games.
THE EIGENVALUE PERTURBATION BOUND FOR ARBITRARY MATRICES
Institute of Scientific and Technical Information of China (English)
Wen Li; Jian-xin Chen
2006-01-01
In this paper we present some new absolute and relative perturbation bounds for the eigenvalue for arbitrary matrices, which improves some recent results. The eigenvalue inclusion region is also discussed.
Sufficient Conditions of Nonsingular H-matrices
Institute of Scientific and Technical Information of China (English)
王广彬; 洪振杰; 高中喜
2004-01-01
From the concept of a diagonally dominant matrix, two sufficient conditions of nonsingular H-matrices were obtained in this paper. An example was given to show that these results improve the known results.
Optimizing the Evaluation of Finite Element Matrices
Kirby, Robert C; Logg, Anders; Scott, L Ridgway; 10.1137/040607824
2012-01-01
Assembling stiffness matrices represents a significant cost in many finite element computations. We address the question of optimizing the evaluation of these matrices. By finding redundant computations, we are able to significantly reduce the cost of building local stiffness matrices for the Laplace operator and for the trilinear form for Navier-Stokes. For the Laplace operator in two space dimensions, we have developed a heuristic graph algorithm that searches for such redundancies and generates code for computing the local stiffness matrices. Up to cubics, we are able to build the stiffness matrix on any triangle in less than one multiply-add pair per entry. Up to sixth degree, we can do it in less than about two. Preliminary low-degree results for Poisson and Navier-Stokes operators in three dimensions are also promising.
Orthogonal Polynomials from Hermitian Matrices II
Odake, Satoru
2016-01-01
This is the second part of the project `unified theory of classical orthogonal polynomials of a discrete variable derived from the eigenvalue problems of hermitian matrices.' In a previous paper, orthogonal polynomials having Jackson integral measures were not included, since such measures cannot be obtained from single infinite dimensional hermitian matrices. Here we show that Jackson integral measures for the polynomials of the big $q$-Jacobi family are the consequence of the recovery of self-adjointness of the unbounded Jacobi matrices governing the difference equations of these polynomials. The recovery of self-adjointness is achieved in an extended $\\ell^2$ Hilbert space on which a direct sum of two unbounded Jacobi matrices acts as a Hamiltonian or a difference Schr\\"odinger operator for an infinite dimensional eigenvalue problem. The polynomial appearing in the upper/lower end of Jackson integral constitutes the eigenvector of each of the two unbounded Jacobi matrix of the direct sum. We also point out...
A Few Applications of Imprecise Matrices
Directory of Open Access Journals (Sweden)
Sahalad Borgoyary
2015-07-01
Full Text Available This article introduces generalized form of extension definition of the Fuzzy set and its complement in the sense of reference function namely in imprecise set and its complement. Discuss Partial presence of element, Membership value of an imprecise number in the normal and subnormal imprecise numbers. Further on the basis of reference function define usual matrix into imprecise form with new notation. And with the help of maximum and minimum operators, obtain some new matrices like reducing imprecise matrices, complement of reducing imprecise matrix etc. Along with discuss some of the classical matrix properties which are hold good in the imprecise matrix also. Further bring out examples of application of the addition of imprecise matrices, subtraction of imprecise matrices etc. in the field of transportation problems.
Balanced random Toeplitz and Hankel Matrices
Basak, Anirban
2010-01-01
Except the Toeplitz and Hankel matrices, the common patterned matrices for which the limiting spectral distribution (LSD) are known to exist, share a common property--the number of times each random variable appears in the matrix is (more or less) same across the variables. Thus it seems natural to ask what happens to the spectrum of the Toeplitz and Hankel matrices when each entry is scaled by the square root of the number of times that entry appears in the matrix instead of the uniform scaling by $n^{-1/2}$. We show that the LSD of these balanced matrices exist and derive integral formulae for the moments of the limit distribution. Curiously, it is not clear if these moments define a unique distribution.
Energy Technology Data Exchange (ETDEWEB)
Kato, T., E-mail: katou.frme.8180@asagi.waseda.jp [Research Institute for Science and Engineering, Waseda University, 3-4-1, Ohkubo, Shinjuku, Tokyo (Japan); Kataoka, J.; Nakamori, T.; Miura, T.; Matsuda, H.; Kishimoto, A. [Research Institute for Science and Engineering, Waseda University, 3-4-1, Ohkubo, Shinjuku, Tokyo (Japan); Sato, K.; Ishikawa, Y.; Yamamura, K.; Nakamura, S.; Kawabata, N. [Solid State Division, Hamamatsu Photonics K. K., 1126-1, Ichino-cho, Hamamatsu, Shizuoka (Japan); Ikeda, H. [ISAS/JAXA, 3-1-1, Yoshinodai, Chuo-ku, Sagamihara-shi, Kanagawa (Japan); Yamamoto, S. [Kobe City College of Technology, 8-3, Gakuenhigashimati, Nishi-ku, Kobe-shi, Hyougo 651-2194 (Japan); Kamada, K. [Materials Research Laboratory, Furukawa Co., Ltd., 1-25-13, Kannondai, Tsukuba, Ibaraki 305-0856 (Japan)
2013-01-21
We have developed a large-area monolithic Multi-Pixel Photon Counter (MPPC) array consisting of 4×4 channels with a three-side buttable package. Each channel has a photosensitive area of 3×3 mm{sup 2} and 3600 Geiger mode avalanche photodiodes (APDs). For typical operational gain of 7.5×10{sup 5} at +20 °C, gain fluctuation over the entire MPPC device is only ±5.6%, and dark count rates (as measured at the 1 p.e. level) amount to ≤400kcps per channel. We first fabricated a gamma-ray camera consisting of the MPPC array with one-to-one coupling to a Ce-doped (Lu,Y){sub 2}(SiO{sub 4})O (Ce:LYSO) crystal array (4×4 array of 3×3×10 mm{sup 3} crystals). Energy and time resolutions of 11.5±0.5% (FWHM at 662 keV) and 493±22ps were obtained, respectively. When using the charge division resistor network, which compiles signals into four position-encoded analog outputs, the ultimate positional resolution is estimated as 0.19 mm in both X and Y directions, while energy resolution of 10.2±0.4% (FWHM) was obtained. Finally, we fabricated submillimeter Ce:LYSO and Ce-doped Gd{sub 3}Ga{sub 3}Al{sub 2}O{sub 12} (Ce:GGAG) scintillator matrices each consisting of 1.0×1.0, 0.7×0.7 and 0.5×0.5 mm{sup 2} pixels, to further improve the spatial resolution. In all types of Ce:LYSO and Ce:GGAG matrices, each crystal was clearly resolved in the position histograms when irradiated by a {sup 137}Cs source. The energy resolutions for 662 keV gamma-rays for each Ce:LYSO and Ce:GGAG scintillator matrix were ≤14.3%. These results suggest excellent potential for its use as a high spatial medical imaging device, particularly in positron emission tomography (PET). -- Highlights: ► We developed a newly designed large-area monolithic MPPC array. ► We obtained fine gain uniformity, and good energy and time resolutions when coupled to the LYSO scintillator. ► We fabricated gamma-ray camera consisting of the MPPC array and submillimeter pixelized LYSO and GGAG scintillators. ► In
Energy Dependence of the Relative Light Output of YAlO3:Ce, Y2SiO5:Ce, and YPO4:Ce Scintillators
Khodyuk, I.V.; Rodnyi, P.A.; Dorenbos, P.
2012-01-01
The nonlinear dependence of the relative light output on the energy deposited in single-crystal scintillation materials YAlO3:Ce (YAP:Ce), Y2SiO5:Ce (YSO:Ce), and YPO4:Ce (YPO:Ce) has been studied. The investigations have been conducted under quasi-monochromatic X-ray excitation in the energy range
Boolean Inner product Spaces and Boolean Matrices
Gudder, Stan; Latremoliere, Frederic
2009-01-01
This article discusses the concept of Boolean spaces endowed with a Boolean valued inner product and their matrices. A natural inner product structure for the space of Boolean n-tuples is introduced. Stochastic boolean vectors and stochastic and unitary Boolean matrices are studied. A dimension theorem for orthonormal bases of a Boolean space is proven. We characterize the invariant stochastic Boolean vectors for a Boolean stochastic matrix and show that they can be used to reduce a unitary m...
Generalized Inverses of Matrices over Rings
Institute of Scientific and Technical Information of China (English)
韩瑞珠; 陈建龙
1992-01-01
Let R be a ring,*be an involutory function of the set of all finite matrices over R. In this pa-per,necessary and sufficient conditions are given for a matrix to have a (1,3)-inverse,(1,4)-inverse,or Morre-Penrose inverse,relative to *.Some results about generalized inverses of matrices over division rings are generalized and improved.
A Euclidean algorithm for integer matrices
DEFF Research Database (Denmark)
Lauritzen, Niels; Thomsen, Jesper Funch
2015-01-01
We present a Euclidean algorithm for computing a greatest common right divisor of two integer matrices. The algorithm is derived from elementary properties of finitely generated modules over the ring of integers.......We present a Euclidean algorithm for computing a greatest common right divisor of two integer matrices. The algorithm is derived from elementary properties of finitely generated modules over the ring of integers....
Infinite Products of Random Isotropically Distributed Matrices
Il'yn, A S; Zybin, K P
2016-01-01
Statistical properties of infinite products of random isotropically distributed matrices are investigated. Both for continuous processes with finite correlation time and discrete sequences of independent matrices, a formalism that allows to calculate easily the Lyapunov spectrum and generalized Lyapunov exponents is developed. This problem is of interest to probability theory, statistical characteristics of matrix T-exponentials are also needed for turbulent transport problems, dynamical chaos and other parts of statistical physics.
A Wegner estimate for Wigner matrices
Maltsev, Anna
2011-01-01
In the first part of these notes, we review some of the recent developments in the study of the spectral properties of Wigner matrices. In the second part, we present a new proof of a Wegner estimate for the eigenvalues of a large class of Wigner matrices. The Wegner estimate gives an upper bound for the probability to find an eigenvalue in an interval $I$, proportional to the size $|I|$ of the interval.
Matrices related to some Fock space operators
Directory of Open Access Journals (Sweden)
Krzysztof Rudol
2011-01-01
Full Text Available Matrices of operators with respect to frames are sometimes more natural and easier to compute than the ones related to bases. The present work investigates such operators on the Segal-Bargmann space, known also as the Fock space. We consider in particular some properties of matrices related to Toeplitz and Hankel operators. The underlying frame is provided by normalised reproducing kernel functions at some lattice points.
Linear algebra for skew-polynomial matrices
Abramov, Sergei; Bronstein, Manuel
2002-01-01
We describe an algorithm for transforming skew-polynomial matrices over an Ore domain in row-reduced form, and show that this algorithm can be used to perform the standard calculations of linear algebra on such matrices (ranks, kernels, linear dependences, inhomogeneous solving). The main application of our algorithm is to desingularize recurrences and to compute the rational solutions of a large class of linear functional systems. It also turns out to be efficient when applied to ordinary co...
Moment matrices, border bases and radical computation
Mourrain, B.; J. B. Lasserre; Laurent, Monique; Rostalski, P.; Trebuchet, Philippe
2013-01-01
In this paper, we describe new methods to compute the radical (resp. real radical) of an ideal, assuming it complex (resp. real) variety is nte. The aim is to combine approaches for solving a system of polynomial equations with dual methods which involve moment matrices and semi-denite programming. While the border basis algorithms of [17] are ecient and numerically stable for computing complex roots, algorithms based on moment matrices [12] allow the incorporation of additional polynomials, ...
Infinite Products of Random Isotropically Distributed Matrices
Il'yn, A. S.; Sirota, V. A.; Zybin, K. P.
2017-01-01
Statistical properties of infinite products of random isotropically distributed matrices are investigated. Both for continuous processes with finite correlation time and discrete sequences of independent matrices, a formalism that allows to calculate easily the Lyapunov spectrum and generalized Lyapunov exponents is developed. This problem is of interest to probability theory, statistical characteristics of matrix T-exponentials are also needed for turbulent transport problems, dynamical chaos and other parts of statistical physics.
MERSENNE AND HADAMARD MATRICES CALCULATION BY SCARPIS METHOD
Directory of Open Access Journals (Sweden)
N. A. Balonin
2014-05-01
Full Text Available Purpose. The paper deals with the problem of basic generalizations of Hadamard matrices associated with maximum determinant matrices or not optimal by determinant matrices with orthogonal columns (weighing matrices, Mersenne and Euler matrices, ets.; calculation methods for the quasi-orthogonal local maximum determinant Mersenne matrices are not studied enough sufficiently. The goal of this paper is to develop the theory of Mersenne and Hadamard matrices on the base of generalized Scarpis method research. Methods. Extreme solutions are found in general by minimization of maximum for absolute values of the elements of studied matrices followed by their subsequent classification according to the quantity of levels and their values depending on orders. Less universal but more effective methods are based on structural invariants of quasi-orthogonal matrices (Silvester, Paley, Scarpis methods, ets.. Results. Generalizations of Hadamard and Belevitch matrices as a family of quasi-orthogonal matrices of odd orders are observed; they include, in particular, two-level Mersenne matrices. Definitions of section and layer on the set of generalized matrices are proposed. Calculation algorithms for matrices of adjacent layers and sections by matrices of lower orders are described. Approximation examples of the Belevitch matrix structures up to 22-nd critical order by Mersenne matrix of the third order are given. New formulation of the modified Scarpis method to approximate Hadamard matrices of high orders by lower order Mersenne matrices is proposed. Williamson method is described by example of one modular level matrices approximation by matrices with a small number of levels. Practical relevance. The efficiency of developing direction for the band-pass filters creation is justified. Algorithms for Mersenne matrices design by Scarpis method are used in developing software of the research program complex. Mersenne filters are based on the suboptimal by
A Brief Historical Introduction to Matrices and Their Applications
Debnath, L.
2014-01-01
This paper deals with the ancient origin of matrices, and the system of linear equations. Included are algebraic properties of matrices, determinants, linear transformations, and Cramer's Rule for solving the system of algebraic equations. Special attention is given to some special matrices, including matrices in graph theory and electrical…
A Brief Historical Introduction to Matrices and Their Applications
Debnath, L.
2014-01-01
This paper deals with the ancient origin of matrices, and the system of linear equations. Included are algebraic properties of matrices, determinants, linear transformations, and Cramer's Rule for solving the system of algebraic equations. Special attention is given to some special matrices, including matrices in graph theory and electrical…
Representation-independent manipulations with Dirac matrices and spinors
2007-01-01
Dirac matrices, also known as gamma matrices, are defined only up to a similarity transformation. Usually, some explicit representation of these matrices is assumed in order to deal with them. In this article, we show how it is possible to proceed without any such assumption. Various important identities involving Dirac matrices and spinors have been derived without assuming any representation at any stage.
Potentielle energibesparelser i det eksisterende byggeri
DEFF Research Database (Denmark)
Wittchen, Kim Bjarne
Denne rapport beskriver tre scenarier for energiforbedring af fem udvalgte bygningskategorier i Danmark. Ud over de beregnede energibesparelser estimers omkostningerne forbundet med at opnå disse. Datagrundlaget bygger på registreringer i energimærkningsdatabasen, som er indhentet i perioden 2006...
Potentielle energibesparelser i det eksisterende byggeri
Wittchen, Kim Bjarne
2009-01-01
Denne rapport beskriver tre scenarier for energiforbedring af fem udvalgte bygningskategorier i Danmark. Ud over de beregnede energibesparelser estimers omkostningerne forbundet med at opnå disse. Datagrundlaget bygger på registreringer i energimærkningsdatabasen, som er indhentet i perioden 2006 til slutningen af 2008, og er ved hjælp af informationer i BBR registeret samt fra Danmarks statistik ekstrapoleret til hele Danmark.
Condition number estimation of preconditioned matrices.
Kushida, Noriyuki
2015-01-01
The present paper introduces a condition number estimation method for preconditioned matrices. The newly developed method provides reasonable results, while the conventional method which is based on the Lanczos connection gives meaningless results. The Lanczos connection based method provides the condition numbers of coefficient matrices of systems of linear equations with information obtained through the preconditioned conjugate gradient method. Estimating the condition number of preconditioned matrices is sometimes important when describing the effectiveness of new preconditionerers or selecting adequate preconditioners. Operating a preconditioner on a coefficient matrix is the simplest method of estimation. However, this is not possible for large-scale computing, especially if computation is performed on distributed memory parallel computers. This is because, the preconditioned matrices become dense, even if the original matrices are sparse. Although the Lanczos connection method can be used to calculate the condition number of preconditioned matrices, it is not considered to be applicable to large-scale problems because of its weakness with respect to numerical errors. Therefore, we have developed a robust and parallelizable method based on Hager's method. The feasibility studies are curried out for the diagonal scaling preconditioner and the SSOR preconditioner with a diagonal matrix, a tri-daigonal matrix and Pei's matrix. As a result, the Lanczos connection method contains around 10% error in the results even with a simple problem. On the other hand, the new method contains negligible errors. In addition, the newly developed method returns reasonable solutions when the Lanczos connection method fails with Pei's matrix, and matrices generated with the finite element method.
Condition number estimation of preconditioned matrices.
Directory of Open Access Journals (Sweden)
Noriyuki Kushida
Full Text Available The present paper introduces a condition number estimation method for preconditioned matrices. The newly developed method provides reasonable results, while the conventional method which is based on the Lanczos connection gives meaningless results. The Lanczos connection based method provides the condition numbers of coefficient matrices of systems of linear equations with information obtained through the preconditioned conjugate gradient method. Estimating the condition number of preconditioned matrices is sometimes important when describing the effectiveness of new preconditionerers or selecting adequate preconditioners. Operating a preconditioner on a coefficient matrix is the simplest method of estimation. However, this is not possible for large-scale computing, especially if computation is performed on distributed memory parallel computers. This is because, the preconditioned matrices become dense, even if the original matrices are sparse. Although the Lanczos connection method can be used to calculate the condition number of preconditioned matrices, it is not considered to be applicable to large-scale problems because of its weakness with respect to numerical errors. Therefore, we have developed a robust and parallelizable method based on Hager's method. The feasibility studies are curried out for the diagonal scaling preconditioner and the SSOR preconditioner with a diagonal matrix, a tri-daigonal matrix and Pei's matrix. As a result, the Lanczos connection method contains around 10% error in the results even with a simple problem. On the other hand, the new method contains negligible errors. In addition, the newly developed method returns reasonable solutions when the Lanczos connection method fails with Pei's matrix, and matrices generated with the finite element method.
RESONANT PHOTOEMISSION OF BULK CeO2 AND NANO-CeO2 FILMS
Institute of Scientific and Technical Information of China (English)
M.I. Abbas; K. Ibrahim; Z.Y. Wu; J. Zhang; F.Q. Liu; H.J. Qian
2001-01-01
Photoemission behaviors of nano-CeO2 films with particle sizes ranging from 8nm 1o50nm and bulk CeO2 in Ce 4d-4f absorption region have been investigated. Resonantenhancements of Ce 4f valance band and Ce 5p bands for nano film and bulk materialhave been observed. The variation of electron density of states in valance bands ofnano and bulk structures of CeO2 is discussed in terms of Ce 4d-4f resonance.
Bayesian Nonparametric Clustering for Positive Definite Matrices.
Cherian, Anoop; Morellas, Vassilios; Papanikolopoulos, Nikolaos
2016-05-01
Symmetric Positive Definite (SPD) matrices emerge as data descriptors in several applications of computer vision such as object tracking, texture recognition, and diffusion tensor imaging. Clustering these data matrices forms an integral part of these applications, for which soft-clustering algorithms (K-Means, expectation maximization, etc.) are generally used. As is well-known, these algorithms need the number of clusters to be specified, which is difficult when the dataset scales. To address this issue, we resort to the classical nonparametric Bayesian framework by modeling the data as a mixture model using the Dirichlet process (DP) prior. Since these matrices do not conform to the Euclidean geometry, rather belongs to a curved Riemannian manifold,existing DP models cannot be directly applied. Thus, in this paper, we propose a novel DP mixture model framework for SPD matrices. Using the log-determinant divergence as the underlying dissimilarity measure to compare these matrices, and further using the connection between this measure and the Wishart distribution, we derive a novel DPM model based on the Wishart-Inverse-Wishart conjugate pair. We apply this model to several applications in computer vision. Our experiments demonstrate that our model is scalable to the dataset size and at the same time achieves superior accuracy compared to several state-of-the-art parametric and nonparametric clustering algorithms.
Using Elimination Theory to construct Rigid Matrices
Kumar, Abhinav; Patankar, Vijay M; N, Jayalal Sarma M
2009-01-01
The rigidity of a matrix A for target rank r is the minimum number of entries of A that must be changed to ensure that the rank of the altered matrix is at most r. Since its introduction by Valiant (1977), rigidity and similar rank-robustness functions of matrices have found numerous applications in circuit complexity, communication complexity, and learning complexity. Almost all nxn matrices over an infinite field have a rigidity of (n-r)^2. It is a long-standing open question to construct infinite families of explicit matrices even with superlinear rigidity when r=Omega(n). In this paper, we construct an infinite family of complex matrices with the largest possible, i.e., (n-r)^2, rigidity. The entries of an nxn matrix in this family are distinct primitive roots of unity of orders roughly exp(n^4 log n). To the best of our knowledge, this is the first family of concrete (but not entirely explicit) matrices having maximal rigidity and a succinct algebraic description. Our construction is based on elimination...
Mirror-Symmetric Matrices and Their Application
Institute of Scientific and Technical Information of China (English)
李国林; 冯正和
2002-01-01
The well-known centrosymmetric matrices correctly reflect mirror-symmetry with no component or only one component on the mirror plane. Mirror-symmetric matrices defined in this paper can represent mirror-symmetric structures with various components on the mirror plane. Some basic properties of mirror-symmetric matrices were studied and applied to interconnection analysis. A generalized odd/even-mode decomposition scheme was developed based on the mirror reflection relationship for mirror-symmetric multiconductor transmission lines (MTLs). The per-unit-length (PUL) impedance matrix Z and admittance matrix Y can be divided into odd-mode and even-mode PUL matrices. Thus the order of the MTL system is reduced from n to k and k+p, where p(≥0)is the conductor number on the mirror plane. The analysis of mirror-symmetric matrices is related to the theory of symmetric group, which is the most effective tool for the study of symmetry.
2012-01-01
Avec l’archive, à laquelle il est souvent associé, le document occupe une place centrale dans les expositions comme dans les publications actuelles sur l’art contemporain. Les présents ouvrages n’ont pas pour objectif d’apporter un éclairage à ce vaste tournant mnémonique qui semble s’emparer des pratiques et des discours sur l’art depuis le début de ce troisième millénaire, même si les contributions de certains de leurs auteurs pointent des éléments conjoncturels (l’après 11 septembre) ou te...
Geometry of 2×2 hermitian matrices
Institute of Scientific and Technical Information of China (English)
HUANG; Liping(黄礼平); WAN; Zhexian(万哲先)
2002-01-01
Let D be a division ring which possesses an involution a→ā. Assume that F = {a∈D|a=ā} is a proper subfield of D and is contained in the center of D. It is pointed out that if D is of characteristic not two, D is either a separable quadratic extension of F or a division ring of generalized quaternions over F and that if D is of characteristic two, D is a separable quadratic extension of F. Thus the trace map Tr: D→F,hermitian matrices over D when n≥3 and now can be deleted. When D is a field, the fundamental theorem of 2×2 hermitian matrices over D has already been proved. This paper proves the fundamental theorem of 2×2 hermitian matrices over any division ring of generalized quaternions of characteristic not two.
INERTIA SETS OF SYMMETRIC SIGN PATTERN MATRICES
Institute of Scientific and Technical Information of China (English)
无
2001-01-01
A sign pattern matrix is a matrixwhose entries are from the set {+ ,- ,0}. The symmetric sign pattern matrices that require unique inertia have recently been characterized. The purpose of this paper is to more generally investigate the inertia sets of symmetric sign pattern matrices. In particular, nonnegative fri-diagonal sign patterns and the square sign pattern with all + entries are examined. An algorithm is given for generating nonnegative real symmetric Toeplitz matrices with zero diagonal of orders n≥3 which have exactly two negative eigenvalues. The inertia set of the square pattern with all + off-diagonal entries and zero diagonal entries is then analyzed. The types of inertias which can be in the inertia set of any sign pattern are also obtained in the paper. Specifically, certain compatibility and consecutiveness properties are established.
Generalized Inverse Eigenvalue Problem for Centrohermitian Matrices
Institute of Scientific and Technical Information of China (English)
刘仲云; 谭艳祥; 田兆录
2004-01-01
In this paper we first consider the existence and the general form of solution to the following generalized inverse eigenvalue problem(GIEP) : given a set of n-dimension complex vectors { xj }jm = 1 and a set of complex numbers { λj} jm = 1, find two n × n centrohermitian matrices A, B such that { xj }jm = 1 and { λj }jm= 1 are the generalized eigenvectors and generalized eigenvalues of Ax = λBx, respectively. We then discuss the optimal approximation problem for the GIEP. More concretely, given two arbitrary matrices, A-, B- ∈Cn×n , we find two matrices A* and B* such that the matrix (A* ,B* ) is closest to (A- ,B-) in the Frobenius norm, where the matrix (A*, B* ) is the solution to the GIEP. We show that the expression of the solution of the optimal approximation is unique and derive the expression for it.
PRM: A database of planetary reflection matrices
Stam, D. M.; Batista, S. F. A.
2014-04-01
We present the PRM database with reflection matrices of various types of planets. With the matrices, users can calculate the total, and the linearly and circularly polarized fluxes of incident unpolarized light that is reflected by a planet for arbitrary illumination and viewing geometries. To allow for flexibility in these geometries, the database does not contain the elements of reflection matrices, but the coefficients of their Fourier series expansion. We describe how to sum these coefficients for given illumination and viewing geometries to obtain the local reflection matrix. The coefficients in the database can also be used to calculate flux and polarization signals of exoplanets, by integrating, for a given planetary phase angle, locally reflected fluxes across the visible part of the planetary disk. Algorithms for evaluating the summation for locally reflected fluxes, as applicable to spatially resolved observations of planets, and the subsequent integration for the disk-integrated fluxes, as applicable to spatially unresolved exoplanets are also in the database
On classification of dynamical r-matrices
Schiffmann, O
1997-01-01
Using recent results of P. Etingof and A. Varchenko on the Classical Dynamical Yang-Baxter equation, we reduce the classification of dynamical r-matrices on a commutative subalgebra l of a Lie algebra g to a purely algebraic problem when l admits a g^l-invariant complement, where g^l is the centralizer of l in g. Using this, we then classify all non skew-symmetric dynamical r-matrices when g is a simple Lie algebra and l a commutative subalgebra containing a regular semisimple element. This partially answers an open problem in [EV] q-alg/9703040, and generalizes the Belavin-Drinfled classification of constant r-matrices. This classification is similar and in some sense simpler than the Belavin-Drinfled classification.
Octonion generalization of Pauli and Dirac matrices
Chanyal, B. C.
2015-10-01
Starting with octonion algebra and its 4 × 4 matrix representation, we have made an attempt to write the extension of Pauli's matrices in terms of division algebra (octonion). The octonion generalization of Pauli's matrices shows the counterpart of Pauli's spin and isospin matrices. In this paper, we also have obtained the relationship between Clifford algebras and the division algebras, i.e. a relation between octonion basis elements with Dirac (gamma), Weyl and Majorana representations. The division algebra structure leads to nice representations of the corresponding Clifford algebras. We have made an attempt to investigate the octonion formulation of Dirac wave equations, conserved current and weak isospin in simple, compact, consistent and manifestly covariant manner.
A Multipath Connection Model for Traffic Matrices
Directory of Open Access Journals (Sweden)
Mr. M. V. Prabhakaran
2015-02-01
Full Text Available Peer-to-Peer (P2P applications have witnessed an increasing popularity in recent years, which brings new challenges to network management and traffic engineering (TE. As basic input information, P2P traffic matrices are of significant importance for TE. Because of the excessively high cost of direct measurement. In this paper,A multipath connection model for traffic matrices in operational networks. Media files can share the peer to peer, the localization ratio of peer to peer traffic. This evaluates its performance using traffic traces collected from both the real peer to peer video-on-demand and file-sharing applications. The estimation of the general traffic matrices (TM then used for sending the media file without traffic. Share the media file, source to destination traffic is not occur. So it give high performance and short time process.
Block TERM factorization of block matrices
Institute of Scientific and Technical Information of China (English)
SHE Yiyuan; HAO Pengwei
2004-01-01
Reversible integer mapping (or integer transform) is a useful way to realize Iossless coding, and this technique has been used for multi-component image compression in the new international image compression standard JPEG 2000. For any nonsingular linear transform of finite dimension, its integer transform can be implemented by factorizing the transform matrix into 3 triangular elementary reversible matrices (TERMs) or a series of single-row elementary reversible matrices (SERMs). To speed up and parallelize integer transforms, we study block TERM and SERM factorizations in this paper. First, to guarantee flexible scaling manners, the classical determinant (det) is generalized to a matrix function, DET, which is shown to have many important properties analogous to those of det. Then based on DET, a generic block TERM factorization,BLUS, is presented for any nonsingular block matrix. Our conclusions can cover the early optimal point factorizations and provide an efficient way to implement integer transforms for large matrices.
Advanced incomplete factorization algorithms for Stiltijes matrices
Energy Technology Data Exchange (ETDEWEB)
Il`in, V.P. [Siberian Division RAS, Novosibirsk (Russian Federation)
1996-12-31
The modern numerical methods for solving the linear algebraic systems Au = f with high order sparse matrices A, which arise in grid approximations of multidimensional boundary value problems, are based mainly on accelerated iterative processes with easily invertible preconditioning matrices presented in the form of approximate (incomplete) factorization of the original matrix A. We consider some recent algorithmic approaches, theoretical foundations, experimental data and open questions for incomplete factorization of Stiltijes matrices which are {open_quotes}the best{close_quotes} ones in the sense that they have the most advanced results. Special attention is given to solving the elliptic differential equations with strongly variable coefficients, singular perturbated diffusion-convection and parabolic equations.
Infinite matrices and their recent applications
Shivakumar, P N; Zhang, Yang
2016-01-01
This monograph covers the theory of finite and infinite matrices over the fields of real numbers, complex numbers and over quaternions. Emphasizing topics such as sections or truncations and their relationship to the linear operator theory on certain specific separable and sequence spaces, the authors explore techniques like conformal mapping, iterations and truncations that are used to derive precise estimates in some cases and explicit lower and upper bounds for solutions in the other cases. Most of the matrices considered in this monograph have typically special structures like being diagonally dominated or tridiagonal, possess certain sign distributions and are frequently nonsingular. Such matrices arise, for instance, from solution methods for elliptic partial differential equations. The authors focus on both theoretical and computational aspects concerning infinite linear algebraic equations, differential systems and infinite linear programming, among others. Additionally, the authors cover topics such ...
Edge fluctuations of eigenvalues of Wigner matrices
Döring, Hanna
2012-01-01
We establish a moderate deviation principle (MDP) for the number of eigenvalues of a Wigner matrix in an interval close to the edge of the spectrum. Moreover we prove a MDP for the $i$th largest eigenvalue close to the edge. The proof relies on fine asymptotics of the variance of the eigenvalue counting function of GUE matrices due to Gustavsson. The extension to large families of Wigner matrices is based on the Tao and Vu Four Moment Theorem. Possible extensions to other random matrix ensembles are commented.
Forecasting Covariance Matrices: A Mixed Frequency Approach
DEFF Research Database (Denmark)
Halbleib, Roxana; Voev, Valeri
This paper proposes a new method for forecasting covariance matrices of financial returns. The model mixes volatility forecasts from a dynamic model of daily realized volatilities estimated with high-frequency data with correlation forecasts based on daily data. This new approach allows...... for flexible dependence patterns for volatilities and correlations, and can be applied to covariance matrices of large dimensions. The separate modeling of volatility and correlation forecasts considerably reduces the estimation and measurement error implied by the joint estimation and modeling of covariance...... matrix dynamics. Our empirical results show that the new mixing approach provides superior forecasts compared to multivariate volatility specifications using single sources of information....
Almost Hadamard matrices: general theory and examples
Banica, Teodor; Zyczkowski, Karol
2012-01-01
We develop a general theory of "almost Hadamard matrices". These are by definition the matrices $H\\in M_N(\\mathbb R)$ having the property that $U=H/\\sqrt{N}$ is orthogonal, and is a local maximum of the 1-norm on O(N). Our study includes a detailed discussion of the circulant case ($H_{ij}=\\gamma_{j-i}$) and of the two-entry case ($H_{ij}\\in\\{x,y\\}$), with the construction of several families of examples, and some 1-norm computations.
Extremal spacings of random unitary matrices
Smaczynski, Marek; Kus, Marek; Zyczkowski, Karol
2012-01-01
Extremal spacings between unimodular eigenvalues of random unitary matrices of size N pertaining to circular ensembles are investigated. Probability distributions for the minimal spacing for various ensembles are derived for N=4. We show that for large matrices the average minimal spacing s_min of a random unitary matrix behaves as N^(-1/(1+B)) for B equal to 0,1 and 2 for circular Poisson, orthogonal and unitary ensembles, respectively. For these ensembles also asymptotic probability distributions P(s_min) are obtained and the statistics of the largest spacing s_max are investigated.
Age differences on Raven's Coloured Progressive Matrices.
Panek, P E; Stoner, S B
1980-06-01
Raven's Coloured Progressive Matrices was administered to 150 subjects (75 males, 75 females) ranging in age from 20 to 86 yr. Subjects were placed into one of three age groups: adult (M age = 27.04 yr.), middle-age (M age = 53.36 yr.), old (M age = 73.78 yr.), with 25 males and 25 females in each age group. Significant differences between age groups on the matrices were obtained after partialing out the effects of educational level, while sex of subject was not significant.
Super Special Codes using Super Matrices
Kandasamy, W B Vasantha; Ilanthenral, K
2010-01-01
The new classes of super special codes are constructed in this book using the specially constructed super special vector spaces. These codes mainly use the super matrices. These codes can be realized as a special type of concatenated codes. This book has four chapters. In chapter one basic properties of codes and super matrices are given. A new type of super special vector space is constructed in chapter two of this book. Three new classes of super special codes namely, super special row code, super special column code and super special codes are introduced in chapter three. Applications of these codes are given in the final chapter.
Energy levels of the Ce activator relative to the YAP(Ce) scintillator host.
Yu, S-W; Carpenter, M H; Ponce, F; Friedrich, S; Lee, J-S; Olalde-Velasco, P; Yang, W L; Åberg, D
2015-05-13
The electronic structure of the cerium-activated yttrium aluminum perovskite [YAP(Ce)] scintillator has been studied by core level x-ray spectroscopy and first-principles calculations. X-ray absorption and emission spectra at the oxygen K-edge of YAP(Ce) and CeO2 have been measured and compared with the calculated partial density of states. With the known band gap of CeO2, the measured oxygen K-edge absorption and emission spectra are used to construct a fixed relation between the valence and conduction bands of YAP and CeO2. This allows us to determine the fundamental band gap of YAP to be 8.1 ± 0.3 eV. A comparison between the cerium M4,5-edges x-ray absorption spectra of the YAP(Ce) and Ce model compounds (CeO2, CeF3, and Ce foils) then shows that the Ce activator is in the desired Ce(3+), with a small fraction of Ce(4+) due to oxidization at the surface. Finally, we determine that the ground state 4f(1) energy level of the Ce(3+) activator lies 1.8 ± 0.5 eV above the top of the valence band of the host YAP.
Determinación y propiedades de H-matrices
SCOTT GUILLEARD, JOSÉ ANTONIO
2015-01-01
[EN] The essential topic of this memory is the study of H-matrices as they were introduced by Ostrowski and hereinafter extended and developed by different authors. In this study three slopes are outlined: 1) the iterative or automatic determination of H-matrices, 2) the properties inherent in the H-matrices and 3) the matrices related to H-matrices. H-matrices acquire every time major relevancy due to the fact that they arise in numerous applications so much in Mathematics,...
A Study of the Kinetics of the Electrochemical Deposition of Ce3+/Ce4+ Oxides
Valov, I.; Guergova, Desislava; Stoychev, D.
The kinetics of cathodic electrodeposition of Ce3+ and/or Ce4+ oxides from alcoholic electrolytes on gold substrates has been studied. It was found that, depending on the oxygen content in the CeCl3-based electrolyte, Ce2O3 (in oxygen atmosphere) or CeO2 (in an inert atmosphere), respectively, were obtained. XPS studies clearly separated the two valence states of Ce ions in the oxide layers. The microstructure of the coatings was analyzed by atomic force microscopy (AFM).
EPR study of concentration dependence in Ce, Ce : La and Ce:Y doped SrF2
Dankert, O.; Vainchtein, David; Datema, H.C.; den Hartog, Hendrik
1995-01-01
Experimental results of an EPR-study of the concentration dependence of the doubly integrated intensity and linewidth of the signals associated with tetragonal Ce3+-F--dipoles in Sr1-xCexF2+x, Sr-1-0.005-x Ce0.005LaxF2+0.005+x and Sr-1-0.005-x Ce0.005YxF2+0.005+x are presented. Both show a nonlinear
Universal portfolios generated by Toeplitz matrices
Tan, Choon Peng; Chu, Sin Yen; Pan, Wei Yeing
2014-06-01
Performance of universal portfolios generated by Toeplitz matrices is studied in this paper. The general structure of the companion matrix of the generating Toeplitz matrix is determined. Empirical performance of the threeband and nine-band Toeplitz universal portfolios on real stock data is presented. Pseudo Toeplitz universal portfolios are studied with promising empirical achievement of wealth demonstrated.
Parametrizations of Positive Matrices With Applications
Tseng, M C; Ramakrishna, V; Zhou, Hong
2006-01-01
This paper reviews some characterizations of positive matrices and discusses which lead to useful parametrizations. It is argued that one of them, which we dub the Schur-Constantinescu parametrization is particularly useful. Two new applications of it are given. One shows all block-Toeplitz states are PPT. The other application is to relaxation rates.
Generation Speed in Raven's Progressive Matrices Test.
Verguts, Tom; De Boeck, Paul; Maris, Eric
1999-01-01
Studied the role of response fluency on results of the Raven's Advanced Progressive Matrices (APM) Test by comparing scores on a test of generation speed (speed of generating rules that govern the items) with APM test performance for 127 Belgian undergraduates. Discusses the importance of generation speed in intelligence. (SLD)
Deconvolution and Regularization with Toeplitz Matrices
DEFF Research Database (Denmark)
Hansen, Per Christian
2002-01-01
of these discretized deconvolution problems, with emphasis on methods that take the special structure of the matrix into account. Wherever possible, analogies to classical DFT-based deconvolution problems are drawn. Among other things, we present direct methods for regularization with Toeplitz matrices, and we show...
Extremal norms of graphs and matrices
Nikiforov, Vladimir
2010-01-01
In the recent years, the trace norm of graphs has been extensively studied under the name of graph energy. In this paper some of this research is extended to more general matrix norms, like the Schatten p-norms and the Ky Fan k-norms. Whenever possible the results are given both for graphs and general matrices.
Numerical Methods for Structured Matrices and Applications
Bini, Dario A; Olshevsky, Vadim; Tyrtsyhnikov, Eugene; van Barel, Marc
2010-01-01
This cross-disciplinary volume brings together theoretical mathematicians, engineers and numerical analysts and publishes surveys and research articles related to the topics where Georg Heinig had made outstanding achievements. In particular, this includes contributions from the fields of structured matrices, fast algorithms, operator theory, and applications to system theory and signal processing.
Generation speed in Raven's Progressive Matrices Test
Verguts, T.; Boeck, P. De; Maris, E.G.G.
1999-01-01
In this paper, we investigate the role of response fluency on a well-known intelligence test, Raven's (1962) Advanced Progressive Matrices (APM) test. Critical in solving this test is finding rules that govern the items. Response fluency is conceptualized as generation speed or the speed at which a
Positivity of Matrices with Generalized Matrix Functions
Institute of Scientific and Technical Information of China (English)
Fuzhen ZHANG
2012-01-01
Using an elementary fact on matrices we show by a unified approach the positivity of a partitioned positive semidefinite matrix with each square block replaced by a compound matrix,an elementary symmetric function or a generalized matrix function.In addition,we present a refined version of the Thompson determinant compression theorem.
Robust stability of interval parameter matrices
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
This note is devoted to the problem of robust stability of interval parameter matrices. Based on some basic facts relating the H∞ norm of a transfer function to the Riccati matrix inequality and Hamilton matrix, several test conditions with parameter perturbation bounds are obtained.
Constructing random matrices to represent real ecosystems.
James, Alex; Plank, Michael J; Rossberg, Axel G; Beecham, Jonathan; Emmerson, Mark; Pitchford, Jonathan W
2015-05-01
Models of complex systems with n components typically have order n(2) parameters because each component can potentially interact with every other. When it is impractical to measure these parameters, one may choose random parameter values and study the emergent statistical properties at the system level. Many influential results in theoretical ecology have been derived from two key assumptions: that species interact with random partners at random intensities and that intraspecific competition is comparable between species. Under these assumptions, community dynamics can be described by a community matrix that is often amenable to mathematical analysis. We combine empirical data with mathematical theory to show that both of these assumptions lead to results that must be interpreted with caution. We examine 21 empirically derived community matrices constructed using three established, independent methods. The empirically derived systems are more stable by orders of magnitude than results from random matrices. This consistent disparity is not explained by existing results on predator-prey interactions. We investigate the key properties of empirical community matrices that distinguish them from random matrices. We show that network topology is less important than the relationship between a species' trophic position within the food web and its interaction strengths. We identify key features of empirical networks that must be preserved if random matrix models are to capture the features of real ecosystems.
Spectral averaging techniques for Jacobi matrices
del Rio, Rafael; Schulz-Baldes, Hermann
2008-01-01
Spectral averaging techniques for one-dimensional discrete Schroedinger operators are revisited and extended. In particular, simultaneous averaging over several parameters is discussed. Special focus is put on proving lower bounds on the density of the averaged spectral measures. These Wegner type estimates are used to analyze stability properties for the spectral types of Jacobi matrices under local perturbations.
Hierarchical matrix approximation of large covariance matrices
Litvinenko, Alexander
2015-11-30
We approximate large non-structured Matérn covariance matrices of size n×n in the H-matrix format with a log-linear computational cost and storage O(kn log n), where rank k ≪ n is a small integer. Applications are: spatial statistics, machine learning and image analysis, kriging and optimal design.
Correspondence Analysis of Archeological Abundance Matrices
de Leeuw, Jan
2007-01-01
In this chapter we discuss the Correspondence Analysis (CA) techniques used in other chapters of this book. CA is presented as a multivariate exploratory technique, as a proximity analysis technique based on Benzecri distances, as a technique to decompose the total chi-square of frequency matrices, and as a least squares method to ﬁt association or ordination models.
Moment matrices, border bases and radical computation
Mourrain, B.; Lasserre, J.B.; Laurent, M.; Rostalski, P.; Trebuchet, P.
2011-01-01
In this paper, we describe new methods to compute the radical (resp. real radical) of an ideal, assuming it complex (resp. real) variety is nte. The aim is to combine approaches for solving a system of polynomial equations with dual methods which involve moment matrices and semi-denite programming.
Moment matrices, border bases and radical computation
Mourrain, B.; Lasserre, J.B.; Laurent, M.; Rostalski, P.; Trebuchet, P.
2013-01-01
In this paper, we describe new methods to compute the radical (resp. real radical) of an ideal, assuming it complex (resp. real) variety is nte. The aim is to combine approaches for solving a system of polynomial equations with dual methods which involve moment matrices and semi-denite programming.
Spectral properties of random triangular matrices
Basu, Riddhipratim; Ganguly, Shirshendu; Hazra, Rajat Subhra
2011-01-01
We provide a relatively elementary proof of the existence of the limiting spectral distribution (LSD) of symmetric triangular patterned matrices and also show their joint convergence. We also derive the expressions for the moments of the LSD of the symmetric triangular Wigner matrix using properties of Catalan words.
Affine processes on positive semidefinite matrices
Cuchiero, Christa; Mayerhofer, Eberhard; Teichmann, Josef
2009-01-01
This paper provides the mathematical foundation for stochastically continuous affine processes on the cone of positive semidefinite symmetric matrices. These matrix-valued affine processes have arisen from a large and growing range of useful applications in finance, including multi-asset option pricing with stochastic volatility and correlation structures, and fixed-income models with stochastically correlated risk factors and default intensities.
Malware Analysis Using Visualized Image Matrices
Directory of Open Access Journals (Sweden)
KyoungSoo Han
2014-01-01
Full Text Available This paper proposes a novel malware visual analysis method that contains not only a visualization method to convert binary files into images, but also a similarity calculation method between these images. The proposed method generates RGB-colored pixels on image matrices using the opcode sequences extracted from malware samples and calculates the similarities for the image matrices. Particularly, our proposed methods are available for packed malware samples by applying them to the execution traces extracted through dynamic analysis. When the images are generated, we can reduce the overheads by extracting the opcode sequences only from the blocks that include the instructions related to staple behaviors such as functions and application programming interface (API calls. In addition, we propose a technique that generates a representative image for each malware family in order to reduce the number of comparisons for the classification of unknown samples and the colored pixel information in the image matrices is used to calculate the similarities between the images. Our experimental results show that the image matrices of malware can effectively be used to classify malware families both statically and dynamically with accuracy of 0.9896 and 0.9732, respectively.
Karoui, Noureddine El
2009-01-01
We place ourselves in the setting of high-dimensional statistical inference, where the number of variables $p$ in a data set of interest is of the same order of magnitude as the number of observations $n$. More formally, we study the asymptotic properties of correlation and covariance matrices, in the setting where $p/n\\to\\rho\\in(0,\\infty),$ for general population covariance. We show that, for a large class of models studied in random matrix theory, spectral properties of large-dimensional correlation matrices are similar to those of large-dimensional covarance matrices. We also derive a Mar\\u{c}enko--Pastur-type system of equations for the limiting spectral distribution of covariance matrices computed from data with elliptical distributions and generalizations of this family. The motivation for this study comes partly from the possible relevance of such distributional assumptions to problems in econometrics and portfolio optimization, as well as robustness questions for certain classical random matrix result...
The primitive matrices of sandwich semigroups of generalized circulant Boolean matrices
Institute of Scientific and Technical Information of China (English)
LIU Jian-ping; CHEN Jin-song
2013-01-01
Let Gn(C) be the sandwich semigroup of generalized circulant Boolean matrices with the sandwich matrix C and GC (Jn) the set of all primitive matrices in Gn(C). In this paper, some necessary and suﬃ cient conditions for A in the semigroup Gn(C) to be primitive are given. We also show that GC (Jn) is a subsemigroup of Gn(C).
Detailed assessment of homology detection using different substitution matrices
Institute of Scientific and Technical Information of China (English)
LI Jing; WANG Wei
2006-01-01
Homology detection plays a key role in bioinformatics, whereas substitution matrix is one of the most important components in homology detection. Thus, besides the improvement of alignment algorithms, another effective way to enhance the accuracy of homology detection is to use proper substitution matrices or even construct new matrices.A study on the features of various matrices and on the comparison of the performances between different matrices in homology detection enable us to choose the most proper or optimal matrix for some specific applications. In this paper, by taking BLOSUM matrices as an example, some detailed features of matrices in homology detection are studied by calculating the distributions of numbers of recognized proteins over different sequence identities and sequence lengths. Our results clearly showed that different matrices have different preferences and abilities to the recognition of remote homologous proteins. Furthermore, detailed features of the various matrices can be used to improve the accuracy of homology detection.
Electrospun human keratin matrices as templates for tissue regeneration.
Sow, Wan Ting; Lui, Yuan Siang; Ng, Kee Woei
2013-04-01
The aim of this work was to study the feasibility of fabricating human hair keratin matrices through electrospinning and to evaluate the potential of these matrices for tissue regeneration. Keratin was extracted from human hair using Na2S and blended with poly(ethylene oxide) in the weight ratio of 60:1 for electrospinning. Physical morphology and chemical properties of the matrices were characterized using scanning electron microscopy and Fourier transform infrared spectroscopy, respectively. Cell viability and morphology of murine and human fibroblasts cultured on the matrices were evaluated through the Live/Dead(®) assay and scanning electron microscopy. Electrospun keratin matrices were successfully produced without affecting the chemical conformation of keratin. Fibroblasts cultured on keratin matrices showed healthy morphology and penetration into matrices at day 7. Electrospun human hair keratin matrices provide a bioinductive and structural environment for cell growth and are thus attractive as alternative templates for tissue regeneration.
Optical response of Ce(III and Eu(II doped hybrid materials synthesised by Sol-Gel processing
Directory of Open Access Journals (Sweden)
Cordoncillo, E.
2000-02-01
Full Text Available This study deals with the preparation of two hybrid organic-inorganic matrices via sol–gel, starting from alkylalkoxisilanes Si(CH3(OCH2CH33 (MTEOS–SiH(CH3(OCH2CH32 (MDES, A system, and SiH(CH3(OCH2CH32 (MDES SiH(OCH2CH33 (TREOS, B system, together with zirconium n-propoxide. Another type-A is carried out by adding acetylacetone, A-acac system. The matrices are characterised by infrared spectroscopy, nuclear magnetic resonance (NMR-MAS, and chemical analysis. Optical characteristics of the matrices have been studied. A-acac and B matrices are doped with an Eu(III salt, and A and B matrices are doped with a Ce(IV salt. Absorption and emission studies show the presence of Eu(II and Ce(III. The transition metal alkoxide that catalysed cleavage of the Si–H bonds was used to reduce in situ at room temperature, the rare earth cations. Depending on chemical strategy, the resulting hybrid materials can be processed as transparent bulks or coatings which exhibit a good transparency in the UV–visible domain. Both the undoped and the rare earth doped matrices exhibit a strong blue emission.
En este trabajo se aborda la preparación de dos matrices híbridas orgánico-inorgánicas por vía sol-gel, a partir de mezclas de alquilalcoxisilanos Si(CH3(OCH2CH33 (MTEOS–SiH(CH3(OCH2CH32 (MDES, sistema A, y SiH(CH3(OCH2CH32 (MDES–SiH(OCH2CH33 (TREOS, sistema B, en presencia de n-propóxido de circonio. Se efectúa una variación del sistema A por adición de acetilacetona, sistema A-acac. Las matrices se caracterizan por espectroscopia infrarroja, resonancia magnética nuclear (RMN-MAS y análisis químico. Se estudian las características ópticas de los materiales obtenidos. Las matrices A-acac y B se dopan con una sal de Eu(III y las matrices A y B con una sal de Ce(IV. Los estudios de absorción y emisión indican la presencia de Eu(II y Ce(III, es decir estos estados de oxidación se han generado in situ a temperatura ambiente en los
Higher-Order Singular Systems and Polynomial Matrices
2005-01-01
There is a one-to-one correspondence between the set of quadruples of matrices defining singular linear time-invariant dynamical systems and a subset of the set of polynomial matrices. This correspondence preserves the equivalence relations introduced in both sets (feedback-similarity and strict equivalence): two quadruples of matrices are feedback-equivalent if, and only if, the polynomial matrices associated to them are also strictly equivalent. Los sistemas lineales singulares...
Decision Matrices: Tools to Enhance Middle School Engineering Instruction
Gonczi, Amanda L.; Bergman, Brenda G.; Huntoon, Jackie; Allen, Robin; McIntyre, Barb; Turner, Sheri; Davis, Jen; Handler, Rob
2017-01-01
Decision matrices are valuable engineering tools. They allow engineers to objectively examine solution options. Decision matrices can be incorporated in K-12 classrooms to support authentic engineering instruction. In this article we provide examples of how decision matrices have been incorporated into 6th and 7th grade classrooms as part of an…
19 CFR 10.90 - Master records and metal matrices.
2010-04-01
... 19 Customs Duties 1 2010-04-01 2010-04-01 false Master records and metal matrices. 10.90 Section... Master Records, and Metal Matrices § 10.90 Master records and metal matrices. (a) Consumption entries... made, of each master record or metal matrix covered thereby. (c) A bond on Customs Form 301,...
Decision Matrices: Tools to Enhance Middle School Engineering Instruction
Gonczi, Amanda L.; Bergman, Brenda G.; Huntoon, Jackie; Allen, Robin; McIntyre, Barb; Turner, Sheri; Davis, Jen; Handler, Rob
2017-01-01
Decision matrices are valuable engineering tools. They allow engineers to objectively examine solution options. Decision matrices can be incorporated in K-12 classrooms to support authentic engineering instruction. In this article we provide examples of how decision matrices have been incorporated into 6th and 7th grade classrooms as part of an…
On Skew Circulant Type Matrices Involving Any Continuous Fibonacci Numbers
Directory of Open Access Journals (Sweden)
Zhaolin Jiang
2014-01-01
inverse matrices of them by constructing the transformation matrices. Furthermore, the maximum column sum matrix norm, the spectral norm, the Euclidean (or Frobenius norm, and the maximum row sum matrix norm and bounds for the spread of these matrices are given, respectively.
Waller, Niels G
2016-01-01
For a fixed set of standardized regression coefficients and a fixed coefficient of determination (R-squared), an infinite number of predictor correlation matrices will satisfy the implied quadratic form. I call such matrices fungible correlation matrices. In this article, I describe an algorithm for generating positive definite (PD), positive semidefinite (PSD), or indefinite (ID) fungible correlation matrices that have a random or fixed smallest eigenvalue. The underlying equations of this algorithm are reviewed from both algebraic and geometric perspectives. Two simulation studies illustrate that fungible correlation matrices can be profitably used in Monte Carlo research. The first study uses PD fungible correlation matrices to compare penalized regression algorithms. The second study uses ID fungible correlation matrices to compare matrix-smoothing algorithms. R code for generating fungible correlation matrices is presented in the supplemental materials.
Local structure of the Ce3+ ion the yellow emitting phosphor YAG:Ce
Ghigna, P.; Pin, S.; Ronda, C.; Speghini, A.; Piccinelli, F.; Bettinelli, M.
2011-01-01
The local structure of the Ce3+ ion in the yellow emitting YAG:Ce phosphor has been studied by Extended X-ray Absorption Fine Structurespectroscopy in the 300−20 K temperature range. It has evidenced that the dopant Ce3+ replaces Y3+ in the garnet structure, giving rise to a significant expan
The role of Ce(III) in BZ oscillating reactions
Nogueira, Paulo A.; Varela, Hamilton; Faria, Roberto B.
2012-03-01
Herein we present results on the oscillatory dynamics in the bromate-oxalic acid-acetone-Ce(III)/Ce(IV) system in batch and also in a CSTR. We show that Ce(III) is the necessary reactant to allow the emergence of oscillations. In batch, oscillations occur with Ce(III) and also with Ce(IV), but no induction period is observed with Ce(III). In a CSTR, no oscillations were found using a freshly prepared Ce(IV), but only when the cerium-containing solution was aged, allowing partial conversion of Ce(IV) to Ce(III) by reaction with acetone.
Lectures on S-matrices and Integrability
Bombardelli, Diego
2016-01-01
In these notes we review the S-matrix theory in (1+1)-dimensional integrable models, focusing mainly on the relativistic case. Once the main definitions and physical properties are introduced, we discuss the factorization of scattering processes due to integrability. We then focus on the analytic properties of the 2-particle scattering amplitude and illustrate the derivation of the S-matrices for all the possible bound states using the so-called bootstrap principle. General algebraic structures underlying the S-matrix theory and its relation with the form factors axioms are briefly mentioned. Finally, we discuss the S-matrices of sine-Gordon and SU(2), SU(3) chiral Gross-Neveu models. This is part of a collection of lecture notes for the Young Researchers Integrability School, organised by the GATIS network at Durham University on 6-10 July 2015.
Inferring Passenger Type from Commuter Eigentravel Matrices
Legara, Erika Fille
2015-01-01
A sufficient knowledge of the demographics of a commuting public is essential in formulating and implementing more targeted transportation policies, as commuters exhibit different ways of traveling. With the advent of the Automated Fare Collection system (AFC), probing the travel patterns of commuters has become less invasive and more accessible. Consequently, numerous transport studies related to human mobility have shown that these observed patterns allow one to pair individuals with locations and/or activities at certain times of the day. However, classifying commuters using their travel signatures is yet to be thoroughly examined. Here, we contribute to the literature by demonstrating a procedure to characterize passenger types (Adult, Child/Student, and Senior Citizen) based on their three-month travel patterns taken from a smart fare card system. We first establish a method to construct distinct commuter matrices, which we refer to as eigentravel matrices, that capture the characteristic travel routines...
Astronomical Receiver Modelling Using Scattering Matrices
King, O G; Copley, C; Davis, R J; Leahy, J P; Leech, J; Muchovej, S J C; Pearson, T J; Taylor, Angela C
2014-01-01
Proper modelling of astronomical receivers is vital: it describes the systematic errors in the raw data, guides the receiver design process, and assists data calibration. In this paper we describe a method of analytically modelling the full signal and noise behaviour of arbitrarily complex radio receivers. We use electrical scattering matrices to describe the signal behaviour of individual components in the receiver, and noise correlation matrices to describe their noise behaviour. These are combined to produce the full receiver model. We apply this approach to a specified receiver architecture: a hybrid of a continous comparison radiometer and correlation polarimeter designed for the C-Band All-Sky Survey. We produce analytic descriptions of the receiver Mueller matrix and noise temperature, and discuss how imperfections in crucial components affect the raw data. Many of the conclusions drawn are generally applicable to correlation polarimeters and continuous comparison radiometers.
Approximate inverse preconditioners for general sparse matrices
Energy Technology Data Exchange (ETDEWEB)
Chow, E.; Saad, Y. [Univ. of Minnesota, Minneapolis, MN (United States)
1994-12-31
Preconditioned Krylov subspace methods are often very efficient in solving sparse linear matrices that arise from the discretization of elliptic partial differential equations. However, for general sparse indifinite matrices, the usual ILU preconditioners fail, often because of the fact that the resulting factors L and U give rise to unstable forward and backward sweeps. In such cases, alternative preconditioners based on approximate inverses may be attractive. We are currently developing a number of such preconditioners based on iterating on each column to get the approximate inverse. For this approach to be efficient, the iteration must be done in sparse mode, i.e., we must use sparse-matrix by sparse-vector type operatoins. We will discuss a few options and compare their performance on standard problems from the Harwell-Boeing collection.
Asymptotic properties of random matrices and pseudomatrices
Lenczewski, Romuald
2010-01-01
We study the asymptotics of sums of matricially free random variables called random pseudomatrices, and we compare it with that of random matrices with block-identical variances. For objects of both types we find the limit joint distributions of blocks and give their Hilbert space realizations, using operators called `matricially free Gaussian operators'. In particular, if the variance matrices are symmetric, the asymptotics of symmetric blocks of random pseudomatrices agrees with that of symmetric random blocks. We also show that blocks of random pseudomatrices are `asymptotically matricially free' whereas the corresponding symmetric random blocks are `asymptotically symmetrically matricially free', where symmetric matricial freeness is obtained from matricial freeness by an operation of symmetrization. Finally, we show that row blocks of square, lower-block-triangular and block-diagonal pseudomatrices are asymptotically free, monotone independent and boolean independent, respectively.
Non-Hermitean Wishart random matrices (I)
Kanzieper, Eugene
2010-01-01
A non-Hermitean extension of paradigmatic Wishart random matrices is introduced to set up a theoretical framework for statistical analysis of (real, complex and real quaternion) stochastic time series representing two "remote" complex systems. The first paper in a series provides a detailed spectral theory of non-Hermitean Wishart random matrices composed of complex valued entries. The great emphasis is placed on an asymptotic analysis of the mean eigenvalue density for which we derive, among other results, a complex-plane analogue of the Marchenko-Pastur law. A surprising connection with a class of matrix models previously invented in the context of quantum chromodynamics is pointed out. This provides one more evidence of the ubiquity of Random Matrix Theory.
Determinants of adjacency matrices of graphs
Directory of Open Access Journals (Sweden)
Alireza Abdollahi
2012-12-01
Full Text Available We study the set of all determinants of adjacency matrices of graphs with a given number of vertices. Using Brendan McKay's data base of small graphs, determinants of graphs with at most $9$ vertices are computed so that the number of non-isomorphic graphs with given vertices whose determinants are all equal to a number is exhibited in a table. Using an idea of M. Newman, it is proved that if $G$ is a graph with $n$ vertices and ${d_1,dots,d_n}$ is the set of vertex degrees of $G$, then $gcd(2m,d^2$ divides the determinant of the adjacency matrix of $G$, where $d=gcd(d_1,dots,d_n$. Possible determinants of adjacency matrices of graphs with exactly two cycles are obtained.
MULTIFRACTAL STRUCTURE AND PRODUCT OF MATRICES
Institute of Scientific and Technical Information of China (English)
Lau Ka-sing
2003-01-01
There is a well established multifractal theory for self-similar measures generated by non-overlapping contractive similutudes.Our report here concerns those with overlaps.In particular we restrict our attention to the important classes of self-similar measures that have matrix representations.The dimension spectra and the Lq-spectra are analyzed through the product of matrices.There are abnormal behaviors on the multifrac-tal structure and they will be discussed in detail.
Ferrers Matrices Characterized by the Rook Polynomials
Institute of Scientific and Technical Information of China (English)
MAHai-cheng; HUSheng-biao
2003-01-01
In this paper,we show that there exist precisely W(A) Ferrers matrices F(C1,C2,…,cm)such that the rook polynomials is equal to the rook polynomial of Ferrers matrix F(b1,b2,…,bm), where A={b1,b2-1,…,bm-m+1} is a repeated set,W(A) is weight of A.
Hierarchical matrix approximation of large covariance matrices
Litvinenko, Alexander
2015-01-07
We approximate large non-structured covariance matrices in the H-matrix format with a log-linear computational cost and storage O(n log n). We compute inverse, Cholesky decomposition and determinant in H-format. As an example we consider the class of Matern covariance functions, which are very popular in spatial statistics, geostatistics, machine learning and image analysis. Applications are: kriging and optimal design
Hierarchical matrix approximation of large covariance matrices
Litvinenko, Alexander
2015-01-05
We approximate large non-structured covariance matrices in the H-matrix format with a log-linear computational cost and storage O(nlogn). We compute inverse, Cholesky decomposition and determinant in H-format. As an example we consider the class of Matern covariance functions, which are very popular in spatial statistics, geostatistics, machine learning and image analysis. Applications are: kriging and op- timal design.
Connection matrices for ultradiscrete linear problems
Energy Technology Data Exchange (ETDEWEB)
Ormerod, Chris [School of Mathematics and Statistics F07, The University of Sydney, Sydney (Australia)
2007-10-19
We present theory outlining associated linear problems for ultradiscrete equations. The appropriate domain for these problems is the max-plus semiring. Our main result is that despite the restrictive nature of the max-plus semiring, it is still possible to define a theory of connection matrices analogous to that of Birkhoff and his school for systems of linear difference equations. We use such theory to provide evidence for the integrability of an ultradiscrete difference equation.
Functional CLT for sample covariance matrices
Bai, Zhidong; Zhou, Wang; 10.3150/10-BEJ250
2010-01-01
Using Bernstein polynomial approximations, we prove the central limit theorem for linear spectral statistics of sample covariance matrices, indexed by a set of functions with continuous fourth order derivatives on an open interval including $[(1-\\sqrt{y})^2,(1+\\sqrt{y})^2]$, the support of the Mar\\u{c}enko--Pastur law. We also derive the explicit expressions for asymptotic mean and covariance functions.
Index matrices towards an augmented matrix calculus
Atanassov, Krassimir T
2014-01-01
This book presents the very concept of an index matrix and its related augmented matrix calculus in a comprehensive form. It mostly illustrates the exposition with examples related to the generalized nets and intuitionistic fuzzy sets which are examples of an extremely wide array of possible application areas. The present book contains the basic results of the author over index matrices and some of its open problems with the aim to stimulating more researchers to start working in this area.
On the exponentials of some structured matrices
Energy Technology Data Exchange (ETDEWEB)
Ramakrishna, Viswanath; Costa, F [Department of Mathematical Sciences and Center for Signals, Systems and Communications, University of Texas at Dallas, PO Box 830688, Richardson, TX 75083 (United States)
2004-12-03
This paper provides explicit techniques to compute the exponentials of a variety of structured 4 x 4 matrices. The procedures are fully algorithmic and can be used to find the desired exponentials in closed form. With one exception, they require no spectral information about the matrix being exponentiated. They rely on a mixture of Lie theory and one particular Clifford algebra isomorphism. These can be extended, in some cases, to higher dimensions when combined with techniques such as Givens rotations.
The spectrum of kernel random matrices
Karoui, Noureddine El
2010-01-01
We place ourselves in the setting of high-dimensional statistical inference where the number of variables $p$ in a dataset of interest is of the same order of magnitude as the number of observations $n$. We consider the spectrum of certain kernel random matrices, in particular $n\\times n$ matrices whose $(i,j)$th entry is $f(X_i'X_j/p)$ or $f(\\Vert X_i-X_j\\Vert^2/p)$ where $p$ is the dimension of the data, and $X_i$ are independent data vectors. Here $f$ is assumed to be a locally smooth function. The study is motivated by questions arising in statistics and computer science where these matrices are used to perform, among other things, nonlinear versions of principal component analysis. Surprisingly, we show that in high-dimensions, and for the models we analyze, the problem becomes essentially linear--which is at odds with heuristics sometimes used to justify the usage of these methods. The analysis also highlights certain peculiarities of models widely studied in random matrix theory and raises some questio...
Quark flavor mixings from hierarchical mass matrices
Energy Technology Data Exchange (ETDEWEB)
Verma, Rohit [Chinese Academy of Sciences, Institute of High Energy Physics, Beijing (China); Rayat Institute of Engineering and Information Technology, Ropar (India); Zhou, Shun [Chinese Academy of Sciences, Institute of High Energy Physics, Beijing (China); Peking University, Center for High Energy Physics, Beijing (China)
2016-05-15
In this paper, we extend the Fritzsch ansatz of quark mass matrices while retaining their hierarchical structures and show that the main features of the Cabibbo-Kobayashi-Maskawa (CKM) matrix V, including vertical stroke V{sub us} vertical stroke ≅ vertical stroke V{sub cd} vertical stroke, vertical stroke V{sub cb} vertical stroke ≅ vertical stroke V{sub ts} vertical stroke and vertical stroke V{sub ub} vertical stroke / vertical stroke V{sub cb} vertical stroke < vertical stroke V{sub td} vertical stroke / vertical stroke V{sub ts} vertical stroke can be well understood. This agreement is observed especially when the mass matrices have non-vanishing (1, 3) and (3, 1) off-diagonal elements. The phenomenological consequences of these for the allowed texture content and gross structural features of 'hierarchical' quark mass matrices are addressed from a model-independent prospective under the assumption of factorizable phases in these. The approximate and analytical expressions of the CKM matrix elements are derived and a detailed analysis reveals that such structures are in good agreement with the observed quark flavor mixing angles and the CP-violating phase at the 1σ level and call upon a further investigation of the realization of these structures from a top-down prospective. (orig.)
Scattering Matrices and Conductances of Leaky Tori
Pnueli, A.
1994-04-01
Leaky tori are two-dimensional surfaces that extend to infinity but which have finite area. It is a tempting idea to regard them as models of mesoscopic systems connected to very long leads. Because of this analogy-scattering matrices on leaky tori are potentially interesting, and indeed-the scattering matrix on one such object-"the" leaky torus-was studied by M. Gutzwiller, who showed that it has chaotic behavior. M. Antoine, A. Comtet and S. Ouvry generalized Gutzwiller‧s result by calculating the scattering matrix in the presence of a constant magnetic field B perpendicular to the surface. Motivated by these results-we generalize them further. We define scattering matrices for spinless electrons on a general leaky torus in the presence of a constant magnetic field "perpendicular" to the surface. From the properties of these matrices we show the following: (a) For integer values of B, Tij (the transition probability from cusp i to cusp j), and hence also the Büttiker conductances of the surfaces, are B-independent (this cannot be interpreted as a kind of Aharonov-Bohm effect since a magnetic force is acting on the electrons). (b) The Wigner time-delay is a monotonically increasing function of B.
On Chinglish in C-E Interpretation
Institute of Scientific and Technical Information of China (English)
XIAO Gui-fang; LIU Jian-zhu; GUI Ren-na
2005-01-01
Based on the author's survey into the different interpretations of some terms from Chinese into English, the paper points out Chinglish exists universally in C-E interpretation.The author also puts forward some proposals on how to avoid and reduce Chinglish in the process of C-E interpretation after exploring its features and causes of Chinglish.
On the Construction of Jointly Superregular Lower Triangular Toeplitz Matrices
DEFF Research Database (Denmark)
Hansen, Jonas; Østergaard, Jan; Kudahl, Johnny
2016-01-01
superregular and product preserving jointly superregular matrices, and extend our explicit constructions of superregular matrices to these cases. Jointly superregular matrices are necessary to achieve optimal decoding capabilities for the case of codes with a rate lower than 1/2, and the product preserving......Superregular matrices have the property that all of their submatrices, which can be full rank are so. Lower triangular superregular matrices are useful for e.g., maximum distance separable convolutional codes as well as for (sequential) network codes. In this work, we provide an explicit design...
The modern origin of matrices and their applications
Debnath, L.
2014-05-01
This paper deals with the modern development of matrices, linear transformations, quadratic forms and their applications to geometry and mechanics, eigenvalues, eigenvectors and characteristic equations with applications. Included are the representations of real and complex numbers, and quaternions by matrices, and isomorphism in order to show that matrices form a ring in abstract algebra. Some special matrices, including Hilbert's matrix, Toeplitz's matrix, Pauli's and Dirac's matrices in quantum mechanics, and Einstein's Pythagorean formula are discussed to illustrate diverse applications of matrix algebra. Included also is a modern piece of information that puts mathematics, science and mathematics education professionals at the forefront of advanced study and research on linear algebra and its applications.
Spectroscopic analysis of LYSO:Ce crystals
Martins, A. F.; Carreira, J. F. C.; Rodrigues, J.; Sedrine, N. Ben; Castro, I. F. C.; Correia, P. M. M.; Veloso, J. F. C. A.; Rino, L.; Monteiro, T.
2017-02-01
Rare earth orthosilicates are among the most widely used scintillator materials in the last decades. Particularly, lutetium-yttrium oxyorthosilicate (LYSO) is known to exhibit great potentialities in the field of radiation detectors for medical imaging. Consequently, an in-depth knowledge of the material properties is of utmost interest for the mentioned applications. In this work the spectroscopic properties of commercial cerium doped lutetium-yttrium oxyorthosilicate crystals (LYSO:Ce) were investigated by Raman spectroscopy, steady state photoluminescence, photoluminescence excitation and time resolved photoluminescence. Site selective excitation was used under steady state (325 nm) and pulsed (266 nm) conditions to separately investigate the temperature dependence of the 5d → 4f Ce1 and Ce2 luminescence, allowing to establish the thermal quenching dependence of the Ce2 optical center. In the case of the Ce1 optical center, a luminescence quantum efficiency of 78% was obtained from 14 K to room temperature with 266 nm photon excitation.
Effects of Ce(III) and CeO₂ nanoparticles on soil-denitrification kinetics.
Dahle, Jessica T; Arai, Yuji
2014-11-01
Cerium (Ce)-based compounds, such as CeO₂ nanoparticles (NPs), have received much attention in the last several years due to their popular applications in industrial and commercial uses. Understanding the impact of CeO₂ NPs on nutrient cycles, a subchronic toxicity study of CeO₂ NPs on soil-denitrification process was performed as a function of particle size (33 and 78 nm), total Ce concentration (50-500 mg L(-1)), and speciation [Ce(IV) vs. Ce(III)]. The antimicrobial effect on the soil-denitrification process was evaluated in both steady-state and zero-order kinetic models to assess particle- and chemical-species specific toxicity. It was found that soluble Ce(III) was far more toxic than Ce(IV)O₂ NPs when an equal total concentration of Ce was evaluated. Particle size-dependent toxicity, species-dependent toxicity, and concentration-dependent toxicity were all observed in this study for both the steady-state and the kinetic evaluations. Changes in physicochemical properties of Ce(IV)O₂ NPs might be important in assessing the environmental fate and toxicity of NPs in aquatic and terrestrial environments.
Machining Characteristics of Ce-ZrO2/CePO4 Ceramics
Institute of Scientific and Technical Information of China (English)
Yu Aibing; Tan Yefa; Yang Xiaoqiang
2004-01-01
Two-phase mixtures of Ce-ZrO2 and monazite-type CePO4 were fabricated. Drilling and grinding experiments were carried out to investigate the machining characteristics of Ce-ZrO2/CePO4 ceramics. The machined surfaces of ceramics and wear surfaces of drill bits were observed with scanning electron microscope. Material removals and grinding forces were measured. The transgranular fracture of CePO4 grains, intergranular fracture between ZrO2 and CePO4 grains, and ductile deformation of ceramics were observed on Ce-ZrO2/CePO4 machined surfaces. With the increase of CePO4 proportion to composites, drilling material removal rates increases and specific normal grinding forces decreases.There existed rapid wear of conventional metal cutting tool is caused by abrasive wear. The experimental results indicate that the weak interfaces and properties of Ce-ZrO2/CePO4 ceramics have influences on material removal and machinability.
Deterministic sensing matrices in compressive sensing: a survey.
Nguyen, Thu L N; Shin, Yoan
2013-01-01
Compressive sensing is a sampling method which provides a new approach to efficient signal compression and recovery by exploiting the fact that a sparse signal can be suitably reconstructed from very few measurements. One of the most concerns in compressive sensing is the construction of the sensing matrices. While random sensing matrices have been widely studied, only a few deterministic sensing matrices have been considered. These matrices are highly desirable on structure which allows fast implementation with reduced storage requirements. In this paper, a survey of deterministic sensing matrices for compressive sensing is presented. We introduce a basic problem in compressive sensing and some disadvantage of the random sensing matrices. Some recent results on construction of the deterministic sensing matrices are discussed.
Matrices with restricted entries and q-analogues of permutations
Lewis, Joel Brewster; Morales, Alejandro H; Panova, Greta; Sam, Steven V; Zhang, Yan
2010-01-01
We study the functions that count matrices of given rank over a finite field with specified positions equal to zero. We show that these matrices are $q$-analogues of permutations with certain restricted values. We obtain a simple closed formula for the number of invertible matrices with zero diagonal, a $q$-analogue of derangements, and a curious relationship between invertible skew-symmetric matrices and invertible symmetric matrices with zero diagonal. In addition, we provide recursions to enumerate matrices and symmetric matrices with zero diagonal by rank, and we frame some of our results in the context of Lie theory. Finally, we provide a brief exposition of polynomiality results for enumeration questions related to those mentioned, and give several open questions.
Temperature dependence of the scintillation properties of Ce:GSO and Ce:GSOZ
Energy Technology Data Exchange (ETDEWEB)
Kurosawa, Shunsuke, E-mail: kurosawa@imr.tohoku.ac.jp [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Sugiyama, Makoto [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Yanagida, Takayuki [New Industry Creation Hatchery Center (NICHe), 6-6-10 Aoba Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Yokota, Yuui [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Yoshikawa, Akira [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); New Industry Creation Hatchery Center (NICHe), 6-6-10 Aoba Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan)
2012-10-21
The light output and decay times of Ce:GSO and Ce:GSOZ scintillators depend on Ce concentration and temperature. We investigated the temperature dependence of the light output and the decay time for Ce:GSO and Ce:GSOZ doped with 0.3 (only GSO), 0.5, 1.0, and 1.5 mol% Ce. These samples were measured with a ruggedized photomultiplier (PMT) (Hamamatsu R6877A) at 175 Degree-Sign C (in the thermostat chamber). Up to 100 Degree-Sign C, the relative light output of all of the samples remained within 10% after correcting the PMT gain, which depends on the temperature. The decay times of the GSO and GSOZ samples with the identical Ce concentrations were equal. Moreover, the quenching energy values for all the samples were equivalent.
Optical and scintillation properties of Ce:(Gd8AE2)(SiO4)6O2 (AE = Mg, Ca, Sr and Ba) crystals
Igashira, Takuya; Mori, Masaki; Okada, Go; Kawaguchi, Noriaki; Yanagida, Takayuki
2017-02-01
1% Ce-doped and non-doped (Gd8AE2)(SiO4)6O2 (AE = Mg, Ca, Sr and Ba) (denoted as GMS, GCS, GSrS and GBS, respectively) single crystals were grown by the Floating Zone (FZ) method to evaluate their optical and scintillation properties. The Ce:GCS and Ce:GSrS samples exhibited scintillation and photoluminescence (PL) around 400 nm due to the 5d-4f transitions of Ce3+. On the other hand, Ce:GMS and Ce:GBS showed much weaker emissions in the wavelength range of 500-650 nm, in which the origin was associated with the host matrices. The PL decay curves were approximated by a double exponential decay function for all the Ce-doped samples. The decay times ranged around 10-30 and 40-90 ns, and faster components coincided with those of the non-doped samples. The scintillation decay curves of Ce-doped samples, on the other hand, were approximated by single exponential functions with slower decay constants than those of PL decay. These constants were very similar to those of non-doped samples. In the X-ray induced afterglow measurements, Ce:GCS exhibited the lowest afterglow level. The pulse height spectrum of these samples showed a full-energy peak under 241Am 5.5 MeV α-ray irradiation. Among these samples, Ce:GSrS exhibited the highest light yield which was around 600 ph/5.5 MeV-α.
Bickel, Peter J
2010-01-01
In the first part of this paper we give an elementary proof of the fact that if an infinite matrix $A$, which is invertible as a bounded operator on $\\ell^2$, can be uniformly approximated by banded matrices then so can the inverse of $A$. We give explicit formulas for the banded approximations of $A^{-1}$ as well as bounds on their accuracy and speed of convergence in terms of their band-width. In the second part we apply these results to covariance matrices $\\Sigma$ of Gaussian processes and study mixing and beta mixing of processes in terms of properties of $\\Sigma$. Finally, we note some applications of our results to statistics.
Factor structure of Raven's Coloured Progressive Matrices
Muniz, Monalisa; Gomes, Cristiano Mauro Assis; Pasian, Sonia Regina
2016-01-01
Abstract This study's objective was to verify the factor structure of Raven's Coloured Progressive Matrices (CPM). The database used included the responses of 1,279 children, 50.2% of which were males with an average age of 8.48 years old and a standard deviation of 1.49 yrs. Confirmatory factor analyses were run to test seven models based on CPM theory and on a Brazilian study addressing the test's structure. The results did not confirm the CPM theoretical proposition concerning the scales b...
Generalized Jones matrices for anisotropic media.
Ortega-Quijano, Noé; Arce-Diego, José Luis
2013-03-25
The interaction of arbitrary three-dimensional light beams with optical elements is described by the generalized Jones calculus, which has been formally proposed recently [Azzam, J. Opt. Soc. Am. A 28, 2279 (2011)]. In this work we obtain the parametric expression of the 3×3 differential generalized Jones matrix (dGJM) for arbitrary optical media assuming transverse light waves. The dGJM is intimately connected to the Gell-Mann matrices, and we show that it provides a versatile method for obtaining the macroscopic GJM of media with either sequential or simultaneous anisotropic effects. Explicit parametric expressions of the GJM for some relevant optical elements are provided.
Jones matrices of perfectly conducting metallic polarizers
Boyer, Philippe
2014-01-01
We deduce from Monomode Modal Method the analytical expressions of transmission and reflexion Jones matrices of an infinitely conducting metallic screen periodically pierced by subwavelength holes. The study is restricted to normal incidence and to the case of neglected evanescent fields (far-field) which covers many common cases. When only one non-degenerate mode propagates in cavities, they take identical forms to those of a polarizer, with Fabry-Perot-like spectral resonant factors depending on bigrating parameters. The isotropic or birefringent properties are then obtained when holes support two orthogonal polarization modes. This basic formalism is finally applied to design compact and efficient metallic half-wave plates.
Algebraic Graph Theory Morphisms, Monoids and Matrices
Knauer, Ulrich
2011-01-01
This is a highly self-contained book about algebraic graph theory which iswritten with a view to keep the lively and unconventional atmosphere of a spoken text to communicate the enthusiasm the author feels about this subject. The focus is on homomorphisms and endomorphisms, matrices and eigenvalues. Graph models are extremely useful for almost all applications and applicators as they play an important role as structuring tools. They allow to model net structures -like roads, computers, telephones -instances of abstract data structures -likelists, stacks, trees -and functional or object orient
Perry, Nicolas
2010-01-01
Concurrent engineering taking into account product life-cycle factors seems to be one of the industrial challenges of the next years. Cost estimation and management are two main strategic tasks that imply the possibility of managing costs at the earliest stages of product development. This is why it is indispensable to let people from economics and from industrial engineering collaborates in order to find the best solution for enterprise progress for economical factors mastering. The objective of this paper is to present who we try to adapt costing methods in a PLM and CE point of view to the new industrial context and configuration in order to give pertinent decision aid for product and process choices. A very important factor is related to cost management problems when developing new products. A case study is introduced that presents how product development actors have referenced elements to product life-cycle costs and impacts, how they have an idea bout economical indicators when taking decisions during t...
Microchips for CE: breakthroughs in real-world food analysis.
Escarpa, Alberto; González, María Cristina; López Gil, Miguel Angel; Crevillén, Agustín G; Hervás, Miriam; García, Miguel
2008-12-01
The well-known complexity of food matrices is approached using CE microchips with different strategies to improve the selectivity and sensitivity of the analysis by avoiding and/or making the sample preparation as simple as possible: (i) enhancing the peak capacity in order to perform direct injection, (ii) using the microchip platform to measure one target analyte/group of analytes with or without separating other related interferences, (iii) integrating sample preparation steps on the microchip platform, and (iv) integrating new analytical tools from nanotechnology in the detection stage. New analyte separations of food significance involving DNA probes, biogenic amines, vanilla flavors, and dyes have been reported as successfully breaking new barriers in areas of high impact in the market, such as transgenic food analysis, as well as the detection of frauds and toxins. Simple microchip layouts are still the most common designs used, though sophisticated new ones are emerging. In contrast to other application areas, electrochemical detection continues to be the most common detection route, followed by LIF, though non-conventional detection routes are also emerging, such as chemiluminescence or UV. In terms of analytical performance, the integration of calibration and quality control on a microchip platform, and remarkable accuracy and precision are being obtained using creative analytical methodologies that enhance the analytical potency of microfluidic chips for their future commercialization. This review critically states the most important advances derived from work done in the field over the past 2-3 years.
Energy Technology Data Exchange (ETDEWEB)
Wagner, C.
1996-12-31
In 1992, Wittum introduced the frequency filtering decompositions (FFD), which yield a fast method for the iterative solution of large systems of linear equations. Based on this method, the tangential frequency filtering decompositions (TFFD) have been developed. The TFFD allow the robust and efficient treatment of matrices with strongly varying coefficients. The existence and the convergence of the TFFD can be shown for symmetric and positive definite matrices. For a large class of matrices, it is possible to prove that the convergence rate of the TFFD and of the FFD is independent of the number of unknowns. For both methods, schemes for the construction of frequency filtering decompositions for unsymmetric matrices have been developed. Since, in contrast to Wittums`s FFD, the TFFD needs only one test vector, an adaptive test vector can be used. The TFFD with respect to the adaptive test vector can be combined with other iterative methods, e.g. multi-grid methods, in order to improve the robustness of these methods. The frequency filtering decompositions have been successfully applied to the problem of the decontamination of a heterogeneous porous medium by flushing.
Replica Fourier Tansforms on Ultrametric Trees, and Block-Diagonalizing Multi-Replica Matrices
de Dominicis, C.; Carlucci, D. M.; Temesvári, T.
1997-01-01
The analysis of objects living on ultrametric trees, in particular the block-diagonalization of 4-replica matrices M^{α β;γ^δ}, is shown to be dramatically simplified through the introduction of properly chosen operations on those objects. These are the Replica Fourier Transforms on ultrametric trees. Those transformations are defined and used in the present work. On montre que l'analyse d'objets vivant sur un arbre ultramétrique, en particulier, la diagonalisation par blocs d'une matrice M^{α β;γ^δ} dépendant de 4-répliques, se simplifie de façon dramatique si l'on introduit les opérations appropriées sur ces objets. Ce sont les Transformées de Fourier de Répliques sur un arbre ultramétrique. Ces transformations sont définies et utilisées dans le présent travail.
APPLICATIONS OF STAIR MATRICES AND THEIR GENERALIZATIONS TO ITERATIVE METHODS
Institute of Scientific and Technical Information of China (English)
SHAO Xin-hui; SHEN Hai-long; LI Chang-jun
2006-01-01
Stair matrices and their generalizations are introduced. The definitions and some properties of the matrices were first given by Lu Hao. This class of matrices provide bases of matrix splittings for iterative methods. The remarkable feature of iterative methods based on the new class of matrices is that the methods are easily implemented for parallel computation. In particular, a generalization of the accelerated overrelaxation method (GAOR) is introduced. Some theories of the AOR method are extended to the generalized method to include a wide class of matrices. The convergence of the new method is derived for Hermitian positive definite matrices. Finally, some examples are given in order to show the superiority of the new method.
A CLASS OF DETERMINISTIC CONSTRUCTION OF BINARY COMPRESSED SENSING MATRICES
Institute of Scientific and Technical Information of China (English)
Li Dandan; Liu Xinji; Xia Shutao; Jiang Yong
2012-01-01
Compressed Sensing (CS) is an emerging technology in the field of signal processing,which can recover a sparse signal by taking very few samples and solving a linear programming problem.In this paper,we study the application of Low-Density Parity-Check (LDPC) Codes in CS.Firstly,we find a sufficient condition for a binary matrix to satisfy the Restricted Isometric Property (RIP).Then,by employing the LDPC codes based on Berlekamp-Justesen (B-J) codes,we construct two classes of binary structured matrices and show that these matrices satisfy RIP.Thus,the proposed matrices could be used as sensing matrices for CS.Finally,simulation results show that the performance of the Droposed matrices can be comparable with the widely used random sensing matrices.
Asymmetric random matrices: What do we need them for?
Drozdz, Stanislaw; Ioannides, Andreas A; 10.5506/APhysPolB.42.987
2011-01-01
Complex systems are typically represented by large ensembles of observations. Correlation matrices provide an efficient formal framework to extract information from such multivariate ensembles and identify in a quantifiable way patterns of activity that are reproducible with statistically significant frequency compared to a reference chance probability, usually provided by random matrices as fundamental reference. The character of the problem and especially the symmetries involved must guide the choice of random matrices to be used for the definition of a baseline reference. For standard correlation matrices this is the Wishart ensemble of symmetric random matrices. The real world complexity however often shows asymmetric information flows and therefore more general correlation matrices are required to adequately capture the asymmetry. Here we first summarize the relevant theoretical concepts. We then present some examples of human brain activity where asymmetric time-lagged correlations are evident and hence...
Are you interested in learning more about how to operate the BenMAP-CE program? A variety of training resources are available, including self-paced exercises, online interactive modules and instructor-led training.
Tensor Dictionary Learning for Positive Definite Matrices.
Sivalingam, Ravishankar; Boley, Daniel; Morellas, Vassilios; Papanikolopoulos, Nikolaos
2015-11-01
Sparse models have proven to be extremely successful in image processing and computer vision. However, a majority of the effort has been focused on sparse representation of vectors and low-rank models for general matrices. The success of sparse modeling, along with popularity of region covariances, has inspired the development of sparse coding approaches for these positive definite descriptors. While in earlier work, the dictionary was formed from all, or a random subset of, the training signals, it is clearly advantageous to learn a concise dictionary from the entire training set. In this paper, we propose a novel approach for dictionary learning over positive definite matrices. The dictionary is learned by alternating minimization between sparse coding and dictionary update stages, and different atom update methods are described. A discriminative version of the dictionary learning approach is also proposed, which simultaneously learns dictionaries for different classes in classification or clustering. Experimental results demonstrate the advantage of learning dictionaries from data both from reconstruction and classification viewpoints. Finally, a software library is presented comprising C++ binaries for all the positive definite sparse coding and dictionary learning approaches presented here.
Bromination of selected pharmaceuticals in water matrices.
Benitez, F Javier; Acero, Juan L; Real, Francisco J; Roldan, Gloria; Casas, Francisco
2011-11-01
The bromination of five selected pharmaceuticals (metoprolol, naproxen, amoxicillin, phenacetin, and hydrochlorothiazide) was studied with these compounds individually dissolved in ultra-pure water. The apparent rate constants for the bromination reaction were determined as a function of the pH, obtaining the sequence amoxicillin>naproxen>hydrochlorothiazide≈phenacetin≈metoprolol. A kinetic mechanism specifying the dissociation reactions and the species formed for each compound according to its pK(a) value and the pH allowed the intrinsic rate constants to be determined for each elementary reaction. There was fairly good agreement between the experimental and calculated values of the apparent rate constants, confirming the goodness of the proposed reaction mechanism. In a second stage, the bromination of the selected pharmaceuticals simultaneously dissolved in three water matrices (a groundwater, a surface water from a public reservoir, and a secondary effluent from a WWTP) was investigated. The pharmaceutical elimination trend agreed with the previously determined rate constants. The influence of the main operating conditions (pH, initial bromine dose, and characteristics of the water matrix) on the degradation of the pharmaceuticals was established. An elimination concentration profile for each pharmaceutical in the water matrices was proposed based on the use of the previously evaluated apparent rate constants, and the theoretical results agreed satisfactorily with experiment. Finally, chlorination experiments performed in the presence of bromide showed that low bromide concentrations slightly accelerate the oxidation of the selected pharmaceuticals during chlorine disinfection.
Moderate deviations for the eigenvalue counting function of Wigner matrices
Doering, Hanna
2011-01-01
We establish a moderate deviation principle (MDP) for the number of eigenvalues of a Wigner matrix in an interval. The proof relies on fine asymptotics of the variance of the eigenvalue counting function of GUE matrices due to Gustavsson. The extension to large families of Wigner matrices is based on the Tao and Vu Four Moment Theorem and applies localization results by Erd\\"os, Yau and Yin. Moreover we investigate families of covariance matrices as well.
Symmetric texture-zero mass matrices and its eigenvalues
Criollo, A
2012-01-01
Within the texture-zeros mechanism, first we provide necessary and sufficient conditions on the characteristic polynomial coefficients so that it has real, simple and positive roots, we traduce these conditions in terms to the invariants of the congruent matrices. Next all symmetric texture-zero mass matrices are counted and classified. Finally we apply in a systematic way the result from the first part to analyze the six, four and two zeros texture matrices presented in the second part.
Wick's theorem and reconstruction schemes for reduced density matrices
Institute of Scientific and Technical Information of China (English)
CHEN Feiwu
2006-01-01
We first obtained a closed form of the Wick's theorem expressed in Grassman wedge product, which is similar to a binomial expansion. With this new expansion, new reconstruction schemes for reduced density matrices are derived rigorously. The higher order reduced density matrices are systematically decomposed into a sum of the lower order reduced density matrices which could be used to solve the contracted Schr(o)dinger equation.
Structural and magnetic properties of Ce/Fe and Ce/FeCoV multilayers
Energy Technology Data Exchange (ETDEWEB)
Tixier, S.; Boeni, P. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Mannix, D.; Stirling, W.G. [Liverpool Univ. (United Kingdom); Lander, G.H.
1997-09-01
Ce/Fe and Ce/FeCoV multilayers have been grown by magnetron sputtering. The interfaces are well defined and the layers are crystalline down to an individual layer thickness of 20 A. Ce/FeCoV multilayers show sharper interfaces than Ce/Fe but some loss of crystallinity is observed. Hysteresis loops obtained by SQUID show different behaviour of the bulk magnetisation as a function of the layer thickness. Fe moments are found by Moessbauer spectroscopy to be perpendicular to the interfaces for multilayers with small periodicity. (author) 2 figs., 2 refs.
Racah matrices and hidden integrability in evolution of knots
Mironov, A.; Morozov, A.; Morozov, An.; Sleptsov, A.
2016-09-01
We construct a general procedure to extract the exclusive Racah matrices S and S bar from the inclusive 3-strand mixing matrices by the evolution method and apply it to the first simple representations R = [ 1 ], [2], [3] and [ 2 , 2 ]. The matrices S and S bar relate respectively the maps (R ⊗ R) ⊗ R bar ⟶ R with R ⊗ (R ⊗ R bar) ⟶ R and (R ⊗ R bar) ⊗ R ⟶ R with R ⊗ (R bar ⊗ R) ⟶ R. They are building blocks for the colored HOMFLY polynomials of arbitrary arborescent (double fat) knots. Remarkably, the calculation realizes an unexpected integrability property underlying the evolution matrices.
Inverse Eigenvalue Problems for Two Special Acyclic Matrices
Directory of Open Access Journals (Sweden)
Debashish Sharma
2016-03-01
Full Text Available In this paper, we study two inverse eigenvalue problems (IEPs of constructing two special acyclic matrices. The first problem involves the reconstruction of matrices whose graph is a path, from given information on one eigenvector of the required matrix and one eigenvalue of each of its leading principal submatrices. The second problem involves reconstruction of matrices whose graph is a broom, the eigen data being the maximum and minimum eigenvalues of each of the leading principal submatrices of the required matrix. In order to solve the problems, we use the recurrence relations among leading principal minors and the property of simplicity of the extremal eigenvalues of acyclic matrices.
Self-dual interval orders and row-Fishburn matrices
Yan, Sherry H F
2011-01-01
Recently, Jel\\'{i}nek derived that the number of self-dual interval orders of reduced size $n$ is twice the number of row-Fishburn matrices of size $n$ by using generating functions. In this paper, we present a bijective proof of this relation by establishing a bijection between two variations of upper-triangular matrices of nonnegative integers. Using the bijection, we provide a combinatorial proof of the refined relations between self-dual Fishburn matrices and row-Fishburn matrices in answer to a problem proposed by Jel\\'{i}nek.
Applications of combinatorial matrix theory to Laplacian matrices of graphs
Molitierno, Jason J
2012-01-01
On the surface, matrix theory and graph theory seem like very different branches of mathematics. However, adjacency, Laplacian, and incidence matrices are commonly used to represent graphs, and many properties of matrices can give us useful information about the structure of graphs. Applications of Combinatorial Matrix Theory to Laplacian Matrices of Graphs is a compilation of many of the exciting results concerning Laplacian matrices developed since the mid 1970s by well-known mathematicians such as Fallat, Fiedler, Grone, Kirkland, Merris, Mohar, Neumann, Shader, Sunder, and more. The text i
32 CFR Appendix B to Part 247 - CE Publications
2010-07-01
... 32 National Defense 2 2010-07-01 2010-07-01 false CE Publications B Appendix B to Part 247... Appendix B to Part 247—CE Publications A. Purpose. CE publications consist of DoD newspapers, magazines... publication. CE publishers sell advertising to cover costs and secure earnings, print the publications, and...
Matrices generadas por adición de díadas (matrices de rango 1): propiedades y aplicaciones
Ortigueira, Manuel D.
1996-01-01
Se estudian las matrices elementales de rango 1 (díadas). Para estas matrices se presentan fórmulas para su factorización, inversión, descomposición en valores propios y valores singulares. Estos resultados son aplicados en análisis recursivo a cualquier matriz, siempre que se descomponga en una suma de matrices de rango 1. Peer Reviewed
Matrices generadas por adición de díadas (matrices de rango 1): propiedades y aplicaciones
Ortigueira, Manuel D.
1996-01-01
Se estudian las matrices elementales de rango 1 (díadas). Para estas matrices se presentan fórmulas para su factorización, inversión, descomposición en valores propios y valores singulares. Estos resultados son aplicados en análisis recursivo a cualquier matriz, siempre que se descomponga en una suma de matrices de rango 1. Peer Reviewed
Salissou, Yacoubou
L'objectif global vise par les travaux de cette these est d'ameliorer la caracterisation des proprietes macroscopiques des materiaux poreux a structure rigide ou souple par des approches inverses et indirectes basees sur des mesures acoustiques faites en tube d'impedance. La precision des approches inverses et indirectes utilisees aujourd'hui est principalement limitee par la qualite des mesures acoustiques obtenues en tube d'impedance. En consequence, cette these se penche sur quatre problemes qui aideront a l'atteinte de l'objectif global precite. Le premier probleme porte sur une caracterisation precise de la porosite ouverte des materiaux poreux. Cette propriete en est une de passage permettant de lier la mesure des proprietes dynamiques acoustiques d'un materiau poreux aux proprietes effectives de sa phase fluide decrite par les modeles semi-phenomenologiques. Le deuxieme probleme traite de l'hypothese de symetrie des materiaux poreux selon leur epaisseur ou un index et un critere sont proposes pour quantifier l'asymetrie d'un materiau. Cette hypothese est souvent source d'imprecision des methodes de caracterisation inverses et indirectes en tube d'impedance. Le critere d'asymetrie propose permet ainsi de s'assurer de l'applicabilite et de la precision de ces methodes pour un materiau donne. Le troisieme probleme vise a mieux comprendre le probleme de transmission sonore en tube d'impedance en presentant pour la premiere fois un developpement exact du probleme par decomposition d'ondes. Ce developpement permet d'etablir clairement les limites des nombreuses methodes existantes basees sur des tubes de transmission a 2, 3 ou 4 microphones. La meilleure comprehension de ce probleme de transmission est importante puisque c'est par ce type de mesures que des methodes permettent d'extraire successivement la matrice de transfert d'un materiau poreux et ses proprietes dynamiques intrinseques comme son impedance caracteristique et son nombre d'onde complexe. Enfin, le
Investigation of degradation mechanisms in composite matrices
Giori, C.; Yamauchi, T.
1982-01-01
Degradation mechanisms were investigated for graphite/polysulfone and graphite/epoxy laminates exposed to ultraviolet and high-energy electron radiations in vacuum up to 960 equivalent sun hours and 10 to the ninth power rads respectively. Based on GC and combined GC/MS analysis of volatile by-products evolved during irradiation, several free radical mechanisms of composite degradation were identified. The radiation resistance of different matrices was compared in terms of G values and quantum yields for gas formation. All the composite materials evaluated show high electron radiation stability and relatively low ultraviolet stability as indicated by low G values and high quantum for gas formation. Mechanical property measurements of irradiated samples did not reveal significant changes, with the possible exception of UV exposed polysulfone laminates. Hydrogen and methane were identified as the main by-products of irradiation, along with unexpectedly high levels of CO and CO2.
Diameter Preserving Surjection on Alternate Matrices
Institute of Scientific and Technical Information of China (English)
Li Ping HUANG
2009-01-01
Let F be a field with |F| ≥ 3, Km be the set of all m × m (m ≥ 4) alternate matrices over F. The arithmetic distance of A, B ∈ Km is d(A, B) := rank(A- B). If d(A, B) = 2, then A and B are said to be adjacent. The diameter of Km is max{d(A, B) : A, B ∈ Km}. Assume that ψ : Km→ Km is a map. We prove the following are equivalent: (a) ψ is a diameter preserving surjection in both directions, (b) ψ is both an adjacency preserving surjection and a diameter preserving map, (c) ψ is a bijective map which preserves the arithmetic distance.
Spirooxazine Photoisomerization and Relaxation in Polymer Matrices
Directory of Open Access Journals (Sweden)
Maria Larkowska
2011-01-01
Full Text Available 9′-Hydroxy-1,3,3-trimethylspiro[indoline-2,3′[3H]naphtha[2,1-b]-1,4oxazine] (SPO-7OH was used in studies of photochromic transformations in polymer matrices. Illumination with UV lamp caused opening the spirostructure of the oxazine with formation of open merocyanine species absorbing at ca. 610 nm. The kinetic studies of thermal relaxation of the open form showed that this process can be described with a biexponential function including both photochemical reaction and rheological behaviour of the polymeric environment. Basing on Arrhenius plot of the rate constant ascribed to the photochemical reaction, the activation energy was determined, which was 66.1 and 84.7 kJ/mole for poly(methyl methacrylate-co-butyl methacrylate and poly(vinylpyrrolidone matrix, respectively.
Carbon nanomaterials in silica aerogel matrices
Energy Technology Data Exchange (ETDEWEB)
Hamilton, Christopher E [Los Alamos National Laboratory; Chavez, Manuel E [Los Alamos National Laboratory; Duque, Juan G [Los Alamos National Laboratory; Gupta, Gautam [Los Alamos National Laboratory; Doorn, Stephen K [Los Alamos National Laboratory; Dattelbaum, Andrew M [Los Alamos National Laboratory; Obrey, Kimberly A D [Los Alamos National Laboratory
2010-01-01
Silica aerogels are ultra low-density, high surface area materials that are extremely good thermal insulators and have numerous technical applications. However, their mechanical properties are not ideal, as they are brittle and prone to shattering. Conversely, single-walled carbon nanotubes (SWCNTs) and graphene-based materials, such as graphene oxide, have extremely high tensile strength and possess novel electronic properties. By introducing SWCNTs or graphene-based materials into aerogel matrices, it is possible to produce composites with the desirable properties of both constituents. We have successfully dispersed SWCNTs and graphene-based materials into silica gels. Subsequent supercritical drying results in monolithic low-density composites having improved mechanical properties. These nanocomposite aerogels have great potential for use in a wide range of applications.
Momentum representation for equilibrium reduced density matrices
Golovko, V A
2011-01-01
The hierarchy of equations for reduced density matrices that describes a thermodynamically equilibrium quantum system obtained earlier by the author is investigated in the momentum representation. In the paper it is shown that the use of the momentum representation opens up new opportunities in studies of macroscopic quantum systems both nonsuperfluid and superfluid. It is found that the distribution over momenta in a quantum fluid is not a Bose or Fermi distribution even in the limit of practically noninteracting particles. The distribution looks like a Maxwellian one although, strictly speaking, it is not Maxwellian. The momentum distribution in a quantum crystal depends upon the interaction potential and the crystalline structure. The momentum distribution in a superfluid contains a delta function. The momentum distribution for the condensate in a superfluid crystal consists of delta peaks that are arranged periodically in momentum space. The periodical structure remains if the condensate crystal is not su...
Statistical properties of random scattering matrices
Seba, P; Zakrzewski, J A; Seba, Petr; Zyczkowski, Karol; Zakrzewski, Jakub
1996-01-01
We discuss the properties of eigenphases of S--matrices in random models simulating classically chaotic scattering. The energy dependence of the eigenphases is investigated and the corresponding velocity and curvature distributions are obtained both theoretically and numerically. A simple formula describing the velocity distribution (and hence the distribution of the Wigner time delay) is derived, which is capable to explain the algebraic tail of the time delay distribution observed recently in microwave experiments. A dependence of the eigenphases on other external parameters is also discussed. We show that in the semiclassical limit (large number of channels) the curvature distribution of S--matrix eigenphases is the same as that corresponding to the curvature distribution of the underlying Hamiltonian and is given by the generalized Cauchy distribution.
Matrices over runtime systems at exascale
Agullo, Emmanuel
2012-11-01
The goal of Matrices Over Runtime Systems at Exascale (MORSE) project is to design dense and sparse linear algebra methods that achieve the fastest possible time to an accurate solution on large-scale multicore systems with GPU accelerators, using all the processing power that future high end systems can make available. In this poster, we propose a framework for describing linear algebra algorithms at a high level of abstraction and delegating the actual execution to a runtime system in order to design software whose performance is portable accross architectures. We illustrate our methodology on three classes of problems: dense linear algebra, sparse direct methods and fast multipole methods. The resulting codes have been incorporated into Magma, Pastix and ScalFMM solvers, respectively. © 2012 IEEE.
Unbiased community detection for correlation matrices
MacMahon, Mel
2013-01-01
A challenging problem in the study of large complex systems is that of resolving, without prior information, the emergent mesoscopic organization determined by groups of units whose dynamical activity is more strongly correlated internally than with the rest of the system. The existing techniques to filter correlations are not explicitly oriented at identifying such modules and suffer from an unavoidable information loss. A promising alternative is that of employing community detection techniques developed in network theory. Unfortunately, the attempts made so far have merely replaced network data with correlation matrices, a procedure that we show to be fundamentally biased due to its inconsistency with the null hypotheses underlying the existing algorithms. Here we introduce, via a consistent redefinition of null models based on Random Matrix Theory, the unbiased correlation-based counterparts of the most popular community detection techniques. After successfully benchmarking our methods, we apply them to s...
CeRh3B2: A ferromagnet with anomalously large Ce 5d spin and orbital magnetic moments
Yaouanc, A.; Dalmas de Réotier, P.; Sanchez, J.-P.; Tschentscher, Th.; Lejay, P.
1998-01-01
We report a high-energy magnetic-Compton-scattering study performed on the ferromagnet CeRh3B2. This technique solely measures the electron spin magnetic moments. In contrast to a number of Ce intermetallics with nonmagnetic elements, the Ce 5d spin moment is found to be large and parallel to the Ce 4f spin moment. Therefore the Kondo effect does not play a key role for CeRh3B2. The inferred large Ce 5d orbital magnetic moment is a signature of the strong spin-orbit interaction for the Ce 5d band.
A convergence analysis of SOR iterative methods for linear systems with weak H-matrices
Directory of Open Access Journals (Sweden)
Zhang Cheng-yi
2016-01-01
Full Text Available It is well known that SOR iterative methods are convergent for linear systems, whose coefficient matrices are strictly or irreducibly diagonally dominant matrices and strong H-matrices (whose comparison matrices are nonsingular M-matrices. However, the same can not be true in case of those iterative methods for linear systems with weak H-matrices (whose comparison matrices are singular M-matrices. This paper proposes some necessary and sufficient conditions such that SOR iterative methods are convergent for linear systems with weak H-matrices. Furthermore, some numerical examples are given to demonstrate the convergence results obtained in this paper.
Dirac matrices for Chern-Simons gravity
Izaurieta, Fernando; Ramírez, Ricardo; Rodríguez, Eduardo
2012-10-01
A genuine gauge theory for the Poincaré, de Sitter or anti-de Sitter algebras can be constructed in (2n - 1)-dimensional spacetime by means of the Chern-Simons form, yielding a gravitational theory that differs from General Relativity but shares many of its properties, such as second order field equations for the metric. The particular form of the Lagrangian is determined by a rank n, symmetric tensor invariant under the relevant algebra. In practice, the calculation of this invariant tensor can be reduced to the computation of the trace of the symmetrized product of n Dirac Gamma matrices Γab in 2n-dimensional spacetime. While straightforward in principle, this calculation can become extremely cumbersome in practice. For large enough n, existing computer algebra packages take an inordinate long time to produce the answer or plainly fail having used up all available memory. In this talk we show that the general formula for the trace of the symmetrized product of 2n Gamma matrices Γab can be written as a certain sum over the integer partitions s of n, with every term being multiplied by a numerical cofficient αs. We then give a general algorithm that computes the α-coefficients as the solution of a linear system of equations generated by evaluating the general formula for different sets of tensors Bab with random numerical entries. A recurrence relation between different coefficients is shown to hold and is used in a second, "minimal" algorithm to greatly speed up the computations. Runtime of the minimal algorithm stays below 1 min on a typical desktop computer for up to n = 25, which easily covers all foreseeable applications of the trace formula.
Dirac matrices for Chern-Simons gravity
Energy Technology Data Exchange (ETDEWEB)
Izaurieta, Fernando; Ramirez, Ricardo; Rodriguez, Eduardo [Departamento de Matematica y Fisica Aplicadas, Universidad Catolica de la Santisima Concepcion, Alonso de Ribera 2850, 4090541 Concepcion (Chile)
2012-10-06
A genuine gauge theory for the Poincare, de Sitter or anti-de Sitter algebras can be constructed in (2n- 1)-dimensional spacetime by means of the Chern-Simons form, yielding a gravitational theory that differs from General Relativity but shares many of its properties, such as second order field equations for the metric. The particular form of the Lagrangian is determined by a rank n, symmetric tensor invariant under the relevant algebra. In practice, the calculation of this invariant tensor can be reduced to the computation of the trace of the symmetrized product of n Dirac Gamma matrices {Gamma}{sub ab} in 2n-dimensional spacetime. While straightforward in principle, this calculation can become extremely cumbersome in practice. For large enough n, existing computer algebra packages take an inordinate long time to produce the answer or plainly fail having used up all available memory. In this talk we show that the general formula for the trace of the symmetrized product of 2n Gamma matrices {Gamma}{sub ab} can be written as a certain sum over the integer partitions s of n, with every term being multiplied by a numerical cofficient {alpha}{sub s}. We then give a general algorithm that computes the {alpha}-coefficients as the solution of a linear system of equations generated by evaluating the general formula for different sets of tensors B{sup ab} with random numerical entries. A recurrence relation between different coefficients is shown to hold and is used in a second, 'minimal' algorithm to greatly speed up the computations. Runtime of the minimal algorithm stays below 1 min on a typical desktop computer for up to n = 25, which easily covers all foreseeable applications of the trace formula.
Robust Generalized Low Rank Approximations of Matrices.
Directory of Open Access Journals (Sweden)
Jiarong Shi
Full Text Available In recent years, the intrinsic low rank structure of some datasets has been extensively exploited to reduce dimensionality, remove noise and complete the missing entries. As a well-known technique for dimensionality reduction and data compression, Generalized Low Rank Approximations of Matrices (GLRAM claims its superiority on computation time and compression ratio over the SVD. However, GLRAM is very sensitive to sparse large noise or outliers and its robust version does not have been explored or solved yet. To address this problem, this paper proposes a robust method for GLRAM, named Robust GLRAM (RGLRAM. We first formulate RGLRAM as an l1-norm optimization problem which minimizes the l1-norm of the approximation errors. Secondly, we apply the technique of Augmented Lagrange Multipliers (ALM to solve this l1-norm minimization problem and derive a corresponding iterative scheme. Then the weak convergence of the proposed algorithm is discussed under mild conditions. Next, we investigate a special case of RGLRAM and extend RGLRAM to a general tensor case. Finally, the extensive experiments on synthetic data show that it is possible for RGLRAM to exactly recover both the low rank and the sparse components while it may be difficult for previous state-of-the-art algorithms. We also discuss three issues on RGLRAM: the sensitivity to initialization, the generalization ability and the relationship between the running time and the size/number of matrices. Moreover, the experimental results on images of faces with large corruptions illustrate that RGLRAM obtains the best denoising and compression performance than other methods.
Robust Generalized Low Rank Approximations of Matrices.
Shi, Jiarong; Yang, Wei; Zheng, Xiuyun
2015-01-01
In recent years, the intrinsic low rank structure of some datasets has been extensively exploited to reduce dimensionality, remove noise and complete the missing entries. As a well-known technique for dimensionality reduction and data compression, Generalized Low Rank Approximations of Matrices (GLRAM) claims its superiority on computation time and compression ratio over the SVD. However, GLRAM is very sensitive to sparse large noise or outliers and its robust version does not have been explored or solved yet. To address this problem, this paper proposes a robust method for GLRAM, named Robust GLRAM (RGLRAM). We first formulate RGLRAM as an l1-norm optimization problem which minimizes the l1-norm of the approximation errors. Secondly, we apply the technique of Augmented Lagrange Multipliers (ALM) to solve this l1-norm minimization problem and derive a corresponding iterative scheme. Then the weak convergence of the proposed algorithm is discussed under mild conditions. Next, we investigate a special case of RGLRAM and extend RGLRAM to a general tensor case. Finally, the extensive experiments on synthetic data show that it is possible for RGLRAM to exactly recover both the low rank and the sparse components while it may be difficult for previous state-of-the-art algorithms. We also discuss three issues on RGLRAM: the sensitivity to initialization, the generalization ability and the relationship between the running time and the size/number of matrices. Moreover, the experimental results on images of faces with large corruptions illustrate that RGLRAM obtains the best denoising and compression performance than other methods.
The effects of Ce3+ and Ce4+ on the stability of fibroblast growth factor-2
Sun, Liwei; Feng, Hao; Jiang, Rui; Niu, Liping; Song, Yu; Feng, Kai; Qi, Chao
2010-11-01
The interaction between tri or tetravalent cerium ions and basic fibroblast growth factor (FGF-2) at 0.1-6: 1 molar ratio under physiological condition was studied by fluorescence and CD spectrum. The different spectra alterations of FGF-2 induced by Ce3+ and Ce4+ showed that Ce3+ and Ce4+ caused different conformational changes of FGF-2 respectively, though both of them destabilized the protein. The instability of FGF-2 in the presence of Ce3+ is involved in the oxidation of its free cystein of protein, but that this treatment nearly does not affect the biological activity. As to Ce4+, it not only induced the conformational changes of protein but also inhibits its activity in a dose-dependent manner, which could be relative to the electrostatic repulsion between Ce4+ and its basic amino acid residues (pI=9.6) or the specific binding of Ce4+ to deprotonated amino acid residues. The interesting results would be helpful to investigate the problem of the stability of proteins.
Measurement of local moment on Ce in CeRh3B2
Devare, S. H.; Devare, H. G.
1987-03-01
We have employed the TDPAC technique to measure the paramagnetic enhancement factor β of140Ce in CeRh3B2 in the temperature range 300 K down to 115 K. Our measurements show that above Tc=115 K, the trend for β(T) closely follows that for trivalent cerium.
Cyclic voltammetry study of Ce(IV/Ce(III redox couple and Ce(IV-F complex in sulfuric acid medium
Directory of Open Access Journals (Sweden)
J. G. He
2016-10-01
Full Text Available In this paper the electrochemical behaviors of Ce(IV/Ce(III redox couple and Ce(IV - F complex in sulfuric acid medium were studied by cyclic voltammetry using a platinum electrode. Both of the Ce(IV/Ce(III couple in Ce(IV solution and Ce(IV - F complex is a quasi-reversible process, and gives a linear correlation between the peak potentials and square root of scan rates, showing that the kinetics of the overall process is diffusion controlled. The complexation of cerium(IV and fluoride is favorable for the oxidation of Ce(III. The kinetic parameters such as diffusion coefficients, anodic transfer coefficients and rate constants were studied.
A Lex-BFS-based recognition algorithm for Robinsonian matrices
Laurent, M.; Seminaroti, M.; Paschos, V.; Widmayer, P.
2015-01-01
Robinsonian matrices arise in the classical seriation problem and play an important role in many applications where unsorted similarity (or dissimilarity) information must be re- ordered. We present a new polynomial time algorithm to recognize Robinsonian matrices based on a new characterization of
A Lex-BFS-based recognition algorithm for Robinsonian matrices
M. Laurent (Monique); M. Seminaroti (Matteo); V. Paschos; P. Widmayer
2015-01-01
htmlabstractRobinsonian matrices arise in the classical seriation problem and play an important role in many applications where unsorted similarity (or dissimilarity) information must be re- ordered. We present a new polynomial time algorithm to recognize Robinsonian matrices based on a new characte
Mutation classes of skew-symmetrizable 3x3 matrices
Seven, Ahmet
2010-01-01
In this paper, we determine representatives for the mutation classes of skew-symmetrizable 3x3 matrices and associated graphs using a natural minimality condition, generalizing and strengthening results of Beineke-Brustle-Hille and Felikson-Shapiro-Tumarkin. Furthermore, we obtain a new numerical invariant for the mutation operation on skew-symmetrizable matrices of arbitrary size.
The Exponent Set of Central Symmetric Primitive Matrices
Institute of Scientific and Technical Information of China (English)
陈佘喜; 胡亚辉
2004-01-01
This paper first establishes a distance inequality of the associated diagraph of a central symmetric primitive matrix, then characters the exponent set of central symmetric primitive matrices, and proves that the exponent set of central symmetric primitive matrices of order n is {1, 2,… ,n-1}. There is no gap in it.
The Modern Origin of Matrices and Their Applications
Debnath, L.
2014-01-01
This paper deals with the modern development of matrices, linear transformations, quadratic forms and their applications to geometry and mechanics, eigenvalues, eigenvectors and characteristic equations with applications. Included are the representations of real and complex numbers, and quaternions by matrices, and isomorphism in order to show…
A Lex-BFS-based recognition algorithm for Robinsonian matrices
M. Laurent (Monique); M. Seminaroti (Matteo); V. Paschos; P. Widmayer
2015-01-01
htmlabstractRobinsonian matrices arise in the classical seriation problem and play an important role in many applications where unsorted similarity (or dissimilarity) information must be re- ordered. We present a new polynomial time algorithm to recognize Robinsonian matrices based on a new
The determinants of some multilevel Vandermonde and Toeplitz matrices
Energy Technology Data Exchange (ETDEWEB)
Cervellino, A [Laboratory for Neutron Scattering, PSI Villigen and ETH Zuerich, CH-5232 Villigen PSI (Switzerland); Ciccariello, S [Dipartimento di Fisica ' G. Galilei' and Unita INFM, Universita di Padova, Via Marzolo 8, I-35131 Padova (Italy)
2005-11-11
The closed algebraic expressions of the determinants of some multivariate (multilevel) Vandermonde matrices and the associated Toeplitz/Karle-Hauptman matrices are worked out. The formula can usefully be applied to evaluate the determinant of the Karle-Hauptman matrix generated by a principal basic set of reflections, the knowledge of which determines the full diffraction pattern of an ideal crystal.
Fusion for AdS/CFT boundary S-matrices
Energy Technology Data Exchange (ETDEWEB)
Nepomechie, Rafael I. [Physics Department, University of Miami,P.O. Box 248046, Coral Gables, FL 33124 (United States); Pimenta, Rodrigo A. [Physics Department, University of Miami,P.O. Box 248046, Coral Gables, FL 33124 (United States); Departamento de Física, Universidade Federal de São Carlos,Caixa Postal 676, CEP 13569-905, São Carlos (Brazil)
2015-11-24
We propose a fusion formula for AdS/CFT worldsheet boundary S-matrices. We show that, starting from the fundamental Y=0 boundary S-matrix, this formula correctly reproduces the two-particle bound-state boundary S-matrices.
Revisiting amino acid substitution matrices for identifying distantly related proteins.
Yamada, Kazunori; Tomii, Kentaro
2014-02-01
Although many amino acid substitution matrices have been developed, it has not been well understood which is the best for similarity searches, especially for remote homology detection. Therefore, we collected information related to existing matrices, condensed it and derived a novel matrix that can detect more remote homology than ever. Using principal component analysis with existing matrices and benchmarks, we developed a novel matrix, which we designate as MIQS. The detection performance of MIQS is validated and compared with that of existing general purpose matrices using SSEARCH with optimized gap penalties for each matrix. Results show that MIQS is able to detect more remote homology than the existing matrices on an independent dataset. In addition, the performance of our developed matrix was superior to that of CS-BLAST, which was a novel similarity search method with no amino acid matrix. We also evaluated the alignment quality of matrices and methods, which revealed that MIQS shows higher alignment sensitivity than that with the existing matrix series and CS-BLAST. Fundamentally, these results are expected to constitute good proof of the availability and/or importance of amino acid matrices in sequence analysis. Moreover, with our developed matrix, sophisticated similarity search methods such as sequence-profile and profile-profile comparison methods can be improved further. Newly developed matrices and datasets used for this study are available at http://csas.cbrc.jp/Ssearch/.
The Modern Origin of Matrices and Their Applications
Debnath, L.
2014-01-01
This paper deals with the modern development of matrices, linear transformations, quadratic forms and their applications to geometry and mechanics, eigenvalues, eigenvectors and characteristic equations with applications. Included are the representations of real and complex numbers, and quaternions by matrices, and isomorphism in order to show…
Reprint of Testing scattering matrices: a compendium of recipes
Hovenier, J.W.; van der Mee, C.V.M.
2010-01-01
Scattering matrices describe the transformation of the Stokes parameters of a beam of radiation upon scattering of that beam. The problems of testing scattering matrices for scattering by one particle and for single scattering by an assembly of particles are addressed. The treatment concerns
Sarymsakov matrices and coordination tasks for multi-agent systems
Xia, Weiguo; Cao, Ming
2012-01-01
The convergence of products of stochastic matrices has proven to be critical in establishing the effectiveness of distributed coordination algorithms for multi-agent systems. After reviewing some classic and recent results on infinite backward products of stochastic matrices, we provide a new
Random Matrices, Combinatorics, Numerical Linear Algebra and Complex Networks
2012-02-16
Littlewood-Offord theorems and the condition number of random discrete matrices, Annals of Mathematics , to appear. [29] T. Tao and V. Vu, The condition...Wigner. On the distribution of the roots of certain symmetric matrices. Annals of Mathematics , 67(2):325327, 1958. Department of Mathematics, Yale, New Haven, CT 06520 E-mail address: van.vu@yale.edu
On Factorization of Coupled Channel Scattering S Matrices
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
We investigate the problem on how to factorize a coupled channel scattering S matrix into a product of simple S matrices. Simple S matrix solutions are found, respecting unitarity, analyticity and being real analytic. The phase shift and its physical meaning produced by these simple S matrices are discussed.
Topological algebras of rapidly decreasing matrices and generalizations
Glockner, Helge
2010-01-01
It is a folklore fact that the rapidly decreasing matrices of countable size form an associative topological algebra whose set of quasi-invertible elements is open, and such that the quasi-inversion map is continuous. We provide a direct proof, which applies more generally to a large class of algebras of weighted matrices with entries in a Banach algebra.
Microstructure of Rh-Ce particles on silica: Interactions between Ce and SiO sub 2
Energy Technology Data Exchange (ETDEWEB)
Krause, K.R.; Schmidt, L.D. (Univ. of Minnesota, Minneapolis (United States)); Schabes-Retchkiman, P. (UNAM, Mexico City (Mexico))
1992-03-01
The authors have characterized the microstructure of Rh/Ce on SiO{sub 2} after heat treatments in H{sub 2} and O{sub 2} using TEM, HREM, XPS, and EELS, focusing on the very stable structures formed after heating in H{sub 2}. After initial reduction at 600 C, Rh is present as 50- to 100-{angstrom} metal particles while the Ce forms a uniform amorphous film of Ce{sup 3+} on the SiO{sub 2}. After oxidation at 600 C, Rh is oxidized to Rh{sub 2}O{sub 3} and spreads over the SiO{sub 2} surface while Ce forms small patches and large (> 1,000 {angstrom}) particles of crystalline CeO{sub 2}. After reduction of the oxidized microstructure at 600 C, Rh metal returns with a less uniform particle size distribution, while Ce is reduced to Ce{sup 3+} and structures indicating strong interactions between Ce and Si are formed. Upon reduction in the presence of Rh, the CeO{sub 2} particles are reduced to crystalline Ce{sub 2}Si{sub 2}O{sub 7}. The Ce silicate nucleates at Rh particles and spreads over the support as large thin single-crystal patches. After reoxidation at 650 C, both Ce silicate and CeO{sub 2} were identified using EELS chemical shifts, indicating that the crystalline silicate, once formed, is stable in oxygen. Ce on SiO{sub 2}also showed interaction between Ce and Si, but no crystalline species formed after reduction and only small crystalline CeO{sub 2} particles formed after oxidation. Thus, the formation of the Ce silicate and the oxidation of Ce to CeO{sub 2} are catalyzed by Rh. This work represents the first direct evidence for the formation of a Ce silicate in this system.
The characterization of doped CeO[sub 2] electrodes in solid oxide fuel cells. [CeCoO; CeNiO; CeMnO
Energy Technology Data Exchange (ETDEWEB)
Pound, B.G. (SRI International, Menlo Park, CA (United States))
1992-05-01
Electrochemical impedance spectroscopy was used to examine doped CeO[sub 2] as a mixed-conducting electrode material for solid oxide fuel cells. Sintered oxide disks with a composition of Ce[sub 0.9]M[sub 0.1]O[sub 2] (M = Co, Ni, and Mn) were used at 1000 degC in two types of cell: Pt/Ce[sub 0.9]M[sub 0.1]O[sub 2]/Pt and Ce[sub 0.9]M[sub 0.1]O[sub 2]/9% Y[sub 2]O[sub 3]-ZrO[sub 2]/Pt. The impedance spectra for the cell containing two platinum electrodes exhibited three depressed semicircles, with the highest-frequency semicircle corresponding to the bulk oxide. Oxygen reduction on Ni- and Co-CeO[sub 2] electrodes in air was studied as a function of voltage using the Y[sub 2]O[sub 3]-ZrO[sub 2] cell. The spectra in this case exhibited two distinct semicircles, with the high-frequency relaxation being ascribed to O[sub 2] reduction at the cathode and the other to mass transport of O[sub 2] or O[sup 2-].
Mercury speciation by CE: an update.
Kubán, Petr; Pelcová, Pavlína; Margetínová, Jana; Kubán, Vlastimil
2009-01-01
This review provides an update on mercury speciation by CE. It includes a brief discussion on physicochemical properties, toxicity and transformation pathways of mercury species (i.e. methyl-, ethyl-, phenyl- and inorganic mercury) and outlines recent trends in Hg speciation by CE. CE is presented as a complementary technique to chromatographic separation techniques, especially in cases when speed, high efficiency and low sample volumes are required. The development of suitable sample preconcentration/isolation (sample stacking, ion exchange, liquid-liquid-liquid extraction, dual-cloud point extraction) to achieve low LODs for analysis of trace concentrations of mercury species in real samples is emphasized. Hyphenation of CE to element specific detectors (i.e. electrothermal atomic absorption spectrometry, atomic fluorescence spectrometry, inductively coupled plasma-optical emission spectrometry, inductively coupled plasma-mass spectrometry) is discussed as well as a potential of CE in interaction studies that may provide useful information on interaction of various Hg species with selected bio-macromolecules.
Directory of Open Access Journals (Sweden)
Pavel Etingof
2007-03-01
Full Text Available Following the works by Wiegmann-Zabrodin, Elbau-Felder, Hedenmalm-Makarov, and others, we consider the normal matrix model with an arbitrary potential function, and explain how the problem of finding the support domain for the asymptotic eigenvalue density of such matrices (when the size of the matrices goes to infinity is related to the problem of Hele-Shaw flows on curved surfaces, considered by Entov and the first author in 1990-s. In the case when the potential function is the sum of a rotationally invariant function and the real part of a polynomial of the complex coordinate, we use this relation and the conformal mapping method developed by Entov and the first author to find the shape of the support domain explicitly (up to finitely many undetermined parameters, which are to be found from a finite system of equations. In the case when the rotationally invariant function is βz^2, this is done by Wiegmann-Zabrodin and Elbau-Felder. We apply our results to the generalized normal matrix model, which deals with random block matrices that give rise to *-representations of the deformed preprojective algebra of the affine quiver of type Â_{m-1}. We show that this model is equivalent to the usual normal matrix model in the large N limit. Thus the conformal mapping method can be applied to find explicitly the support domain for the generalized normal matrix model.
Time series, correlation matrices and random matrix models
Energy Technology Data Exchange (ETDEWEB)
Vinayak [Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, C.P. 62210 Cuernavaca (Mexico); Seligman, Thomas H. [Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, C.P. 62210 Cuernavaca, México and Centro Internacional de Ciencias, C.P. 62210 Cuernavaca (Mexico)
2014-01-08
In this set of five lectures the authors have presented techniques to analyze open classical and quantum systems using correlation matrices. For diverse reasons we shall see that random matrices play an important role to describe a null hypothesis or a minimum information hypothesis for the description of a quantum system or subsystem. In the former case various forms of correlation matrices of time series associated with the classical observables of some system. The fact that such series are necessarily finite, inevitably introduces noise and this finite time influence lead to a random or stochastic component in these time series. By consequence random correlation matrices have a random component, and corresponding ensembles are used. In the latter we use random matrices to describe high temperature environment or uncontrolled perturbations, ensembles of differing chaotic systems etc. The common theme of the lectures is thus the importance of random matrix theory in a wide range of fields in and around physics.
The semi-dynamical reflection equation: solutions and structure matrices
Energy Technology Data Exchange (ETDEWEB)
Avan, J; Zambon, C [Laboratoire de Physique Theorique et Modelisation, Universite de Cergy-Pontoise (CNRS UMR 8089), Saint-Martin 2 avenue Adolphe Chauvin, 95302 Cergy-Pontoise Cedex (France)], E-mail: avan@u-cergy.fr, E-mail: cristina.zambon@u-cergy.fr
2008-05-16
Explicit solutions of the non-constant semi-dynamical reflection equation are constructed, together with suitable parametrizations of their structure matrices. Considering the semi-dynamical reflection equation with rational non-constant Arutyunov-Chekhov-Frolov structure matrices, and a specific meromorphic ansatz, it is found that only two sets of the previously found constant solutions are extendible to the non-constant case. In order to simplify future constructions of spin-chain Hamiltonians, a parametrization procedure is applied explicitly to all elements of the semi-dynamical reflection equation available. Interesting expressions for 'twists' and R-matrices entering the parametrization procedure are found. In particular, some expressions for the R-matrices seem to appear here for the first time. In addition, a new set of consistent structure matrices for the semi-dynamical reflection equation is obtained.
Okada, Tetsuo
2007-10-01
Liquid-core waveguide (LCW) brings about several advantages in CE. This review discusses some aspects of fundamental and practical importance involved in this method. Sensitivity in absorption and fluorescence detection is in general improved by more than one order of magnitude over usual crossbeam detection arrangements; the improvements come from the long light path in absorption detection and low light scattering in fluorescence detection. Versatile instrumental arrangements are another advantage of LCW in CE, leading to several detection schemes, some of which provide information that is not gained by usual capillary-end crossbeam detection, e.g. whole-capillary imaging, simultaneous monitoring of multicapillary separation, and kinetic evaluation. The high potential and perspectives of LCW in CE are discussed based on the state-of-the-art developments.
New approaches in sensitive chiral CE.
Sánchez-Hernández, Laura; Guijarro-Diez, Miguel; Marina, María Luisa; Crego, Antonio L
2014-01-01
CE has shown to have a big potential for chiral separations, with advantages such as high efficiency, high resolution, and low sample and reagents consumption. Nevertheless, when UV detection is employed, CE has some drawbacks, especially the low sensitivity obtained due to the short optical path length. Notwithstanding, sensitivity improvements can be achieved when different approaches are employed, such as sample treatment strategies (off-line or on-line), in-capillary sample preconcentration techniques, and/or alternative detection systems to UV-Vis (such as fluorescence, conductimetry, electrochemiluminiscence, MS, etc.). This article reviews the most recent methodological and instrumental advances reported from June 2011 to May 2013 for enhancing the sensitivity in chiral analysis by CE. The sensitivity achieved for the enantioseparated analytes and the applications carried out using the developed methodologies are also summarized.
H-MATRICES AND S-DOUBLY DIAGONALLY DOMINANT MATRICES%H-矩阵和S-双对角占优矩阵
Institute of Scientific and Technical Information of China (English)
杨月婷; 徐成贤
2004-01-01
In this paper, the concept of the s-doubly diagonally dominant matrices is introduced and the properties of these matrices are discussed. With the properties of the s-doubly diagonally dominant matrices and the properties of comparison matrices, some equivalent conditions for H-matrices are presented. These conditions generalize and improve existing results about the equivalent conditions for H-matrices. Applications and examples using these new equivalent conditions are also presented, and a new inclusion region of k-multiple eigenvalues of matrices is obtained.
Laser altimeter of CE-1 payloads system
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
The design and operation of the Laser Altimeter of CE-1 Payloads System are presented in this paper.The paper includes the design of the system and spacecraft-level laser,the description of the emitting-system and receiving system,and the testing of the laser altimeter.The CE-1 laser altimeter is the first Chinese deep-space probe using a laser.It has one beam and operates at 1 Hz,with a nominal accuracy of 5 m.The laser altimeter has operated successfully in lunar orbit since November 28,2007.It has obtained 9120 thousand data values about the lunar altitude.
Indian Academy of Sciences (India)
K G Suresh; S Radha; A K Nigam
2002-05-01
Effect of Al substitution on the magnetic properties of Ce(Ga1-Al)2 ( = 0, 0.1 and 0.5) system has been studied. The magnetic state of CeGa2 is found to be FM with a C of 8 K, whereas the compounds with =0.1 and 0.5 are AFM and possess N of about 9 K. These two compounds undergo metamagnetic transition and the critical ﬁelds are about 1.2 T and 0.5 T, respectively at 2 K. These variations are explained on the basis of helical spin structure in these compounds.
Energy Technology Data Exchange (ETDEWEB)
Glorieux, B.; Jorion, F.; Montel, J.M.; Matecki, M.; Deschanels, X.; Coutures, JP
2004-07-01
In response to the 1991 French radioactive waste management act, a research program was set up between the CNRS, the CEA and French universities to propose effective minor actinide disposal matrices capable of loading 10 wt% of actinide oxides and ensuring a hundred-fold better leaching performance than 'R7T7' glass. The lanthanide ortho-phosphates LaPO{sub 4} could constitute an excellent matrix for this purpose. In this type of structure, the (PO{sub 4}){sup 3-} negative entity is compensated by trivalent cations such as La, Ce, Gd, Pu, Am (monazite) or equal fractions of divalent and tetravalent cations such as Ca{sup 2+}Th{sup 4+}, Ca{sup 2+}U{sup 4+}, Ca{sup 2+}Np{sup 4+} (brabantite). Previous leach tests and geological discoveries have shown that these materials are highly resistant to leaching and conserve their crystalline state even in aqueous media. These points led us to investigate the incorporation of 10 wt% PuO{sub 2} in monazite and brabantite materials and to study the effects of self-irradiation on their structural states. Prior to plutonium conditioning tests, experiments were performed in the laboratory using cerium and thorium oxides according to the following reactions: (1-3x)LaPO{sub 4} + 2xCe{sup 4+}O{sub 2} + xLa(PO{sub 3}){sub 3} {yields} La{sub 1-2x}Ce{sub 2x}{sup 3+}PO{sub 4} + x/2O{sub 2}; (1-3x)LaPO{sub 4} + xTh{sup 4+}O{sub 2} + xCaO + xLa(PO{sub 3}){sub 3} {yields} La{sub 1-2x}Ca{sub x}Th{sub x}{sup 4+}PO{sub 4}. Cerium oxide was used to study the reduction of a tetravalent cation to a trivalent state in a phosphate structure and to prepare for Pu{sup 3+} conditioning. Thorium was used to study the conditioning of tetravalent cations such as Pu{sup 4+}. The parameters and sintering reaction of the final product were optimized. In a radioactive laboratory, PuO{sub 2} was then substituted for CeO{sub 2} and ThO{sub 2} in the first and second reactions mentioned above, respectively. The synthesis and sintering procedures were
Neutron scattering from -Ce at epithermal neutron energies
Indian Academy of Sciences (India)
A P Murani
2008-10-01
Neutron scattering data, using neutrons of incident energies as high as 2 eV, on -Ce and -Ce-like systems such as CeRh2, CeNi2, CeFe24, CeRu2, and many others that point clearly to the substantially localized 4f electronic state in these systems are reviewed. The present interpretation is contrary to the widely held view that the 4f electrons in these systems form a narrow itinerant electron 4f band.
Mechanically implementable accommodation matrices for passive force control
Energy Technology Data Exchange (ETDEWEB)
Goswami, A. [Univ. of Pennsylvania, Philadelphia, PA (United States). Center for Human Modeling and Simulation; Peshkin, M. [Northwestern Univ., Evanston, IL (United States). Dept. of Mechanical Engineering
1999-08-01
Robot force control implemented by means of passive mechanical devices has inherent advantages over active implementations with regard to stability, response rapidity, and physical robustness. The class of devices considered in this paper consists of a Stewart platform-type mechanism interconnected with a network of adjustable mechanical elements such as springs and dampers. The control law repertoire of such a device, imagined as a robot wrist, is given by the range of admittance matrices that it may be programmed to possess. This paper focuses on wrists incorporating damper networks for which the admittance matrices reduce to accommodation or inverse-damping matrices. The authors show that a hydraulic network of fully adjustable damper elements may attain any diagonally dominant accommodation matrix. They describe the technique of selecting the individual damping coefficients to design a desired matrix. They identify the set of dominant matrices as a polyhedral convex cone in the space of matrix entries, and show that each dominant matrix can be composed of a positive linear combination of a fixed set of basis matrices. The overall wrist-accommodation matrix is obtained by projecting the accommodation matrix of the damper network through the wrist kinematics. The linear combination of the dominant basis matrices projected through the wrist kinematics generates the entire space of mechanically implementable force-control laws. The authors quantify the versatility of mechanically implementable force-control laws by comparing this space to the space of all matrices.
Limits of spiked random matrices II
Bloemendal, Alex
2011-01-01
The top eigenvalues of rank r spiked real Wishart matrices and additively perturbed Gaussian orthogonal ensembles are known to exhibit a phase transition in the large size limit. We show that they have limiting distributions for near-critical perturbations, fully resolving the conjecture of Baik, Ben Arous and P\\'ech\\'e (2005). The starting point is a new (2r+1)-diagonal form that is algebraically natural to the problem; for both models it converges to a certain random Schr\\"odinger operator on the half-line with r x r matrix-valued potential. The perturbation determines the boundary condition, and the low-lying eigenvalues describe the limit jointly over all perturbations in a fixed subspace. We treat the real, complex and quaternion (beta = 1,2,4) cases simultaneously. We also characterize the limit laws in terms of a diffusion related to Dyson's Brownian motion, and further in terms of a linear parabolic PDE; here beta is simply a parameter. At beta = 2 the PDE appears to reconcile with known Painlev\\'e fo...
NOTE ON REGULAR D-OPTIMAL MATRICES
Institute of Scientific and Technical Information of China (English)
李乔良
2003-01-01
Let A be aj ×d (0,1) matrix. It is known that ifj = 2k-1is odd, then det(AAT) ≤(j+1)((j+1)d/4j)j; ifj is even, then det(AAT) ≤ (j+1)((j+2)d/4(j+1))j. A is called a regularD-optimal matrix if it satisfies the equality of the above bounds. In this note, it is proved thatifj = 2k - 1 is odd, then A is a regular D-optimal matrix if and only if A is the adjacent matrixof a (2k - 1, k, (j + 1)d/4j)-BIBD; if j ＝ 2k is even, then A is a regular D-optimal matrix ifand only if A can be obtained from the adjacent matrix B of a (2k + 1, k + 1, (j + 2)d/4(j + 1))-BIBD by deleting any one row from B. Three 21 × 42 regular D-optimal matrices, which wereunknown in [11], are also provided.
Generalized graph states based on Hadamard matrices
Energy Technology Data Exchange (ETDEWEB)
Cui, Shawn X. [Department of Mathematics, University of California, Santa Barbara, California 93106 (United States); Yu, Nengkun [Institute for Quantum Computing, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Department of Mathematics and Statistics, University of Guelph, Guelph, Ontario N1G 2W1 (Canada); UTS-AMSS Joint Research Laboratory for Quantum Computation and Quantum Information Processing, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing 100190 (China); Zeng, Bei [Institute for Quantum Computing, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); Department of Mathematics and Statistics, University of Guelph, Guelph, Ontario N1G 2W1 (Canada); Canadian Institute for Advanced Research, Toronto, Ontario M5G 1Z8 (Canada)
2015-07-15
Graph states are widely used in quantum information theory, including entanglement theory, quantum error correction, and one-way quantum computing. Graph states have a nice structure related to a certain graph, which is given by either a stabilizer group or an encoding circuit, both can be directly given by the graph. To generalize graph states, whose stabilizer groups are abelian subgroups of the Pauli group, one approach taken is to study non-abelian stabilizers. In this work, we propose to generalize graph states based on the encoding circuit, which is completely determined by the graph and a Hadamard matrix. We study the entanglement structures of these generalized graph states and show that they are all maximally mixed locally. We also explore the relationship between the equivalence of Hadamard matrices and local equivalence of the corresponding generalized graph states. This leads to a natural generalization of the Pauli (X, Z) pairs, which characterizes the local symmetries of these generalized graph states. Our approach is also naturally generalized to construct graph quantum codes which are beyond stabilizer codes.
Striations in PageRank-Ordered Matrices
Pennycuff, Corey
2016-01-01
Patterns often appear in a variety of large, real-world networks, and interesting physical phenomena are often explained by network topology as in the case of the bow-tie structure of the World Wide Web, or the small world phenomenon in social networks. The discovery and modelling of such regular patterns has a wide application from disease propagation to financial markets. In this work we describe a newly discovered regularly occurring striation pattern found in the PageRank ordering of adjacency matrices that encode real-world networks. We demonstrate that these striations are the result of well-known graph generation processes resulting in regularities that are manifest in the typical neighborhood distribution. The spectral view explored in this paper encodes a tremendous amount about the explicit and implicit topology of a given network, so we also discuss the interesting network properties, outliers and anomalies that a viewer can determine from a brief look at the re-ordered matrix.
On some Toeplitz matrices and their inversions
Directory of Open Access Journals (Sweden)
S. Dutta
2014-10-01
Full Text Available In this article, using the difference operator B(a[m], we introduce a lower triangular Toeplitz matrix T which includes several difference matrices such as Δ(1,Δ(m,B(r,s,B(r,s,t, and B(r̃,s̃,t̃,ũ in different special cases. For any x ∈ w and m∈N0={0,1,2,…}, the difference operator B(a[m] is defined by (B(a[m]xk=ak(0xk+ak-1(1xk-1+ak-2(2xk-2+⋯+ak-m(mxk-m,(k∈N0 where a[m] = {a(0, a(1, …, a(m} and a(i = (ak(i for 0 ⩽ i ⩽ m are convergent sequences of real numbers. We use the convention that any term with negative subscript is equal to zero. The main results of this article relate to the determination and applications of the inverse of the Toeplitz matrix T.
Visualizing complex (hydrological) systems with correlation matrices
Haas, J. C.
2016-12-01
When trying to understand or visualize the connections of different aspects of a complex system, this often requires deeper understanding to start with, or - in the case of geo data - complicated GIS software. To our knowledge, correlation matrices have rarely been used in hydrology (e.g. Stoll et al., 2011; van Loon and Laaha, 2015), yet they do provide an interesting option for data visualization and analysis. We present a simple, python based way - using a river catchment as an example - to visualize correlations and similarities in an easy and colorful way. We apply existing and easy to use python packages from various disciplines not necessarily linked to the Earth sciences and can thus quickly show how different aquifers work or react, and identify outliers, enabling this system to also be used for quality control of large datasets. Going beyond earlier work, we add a temporal and spatial element, enabling us to visualize how a system reacts to local phenomena such as for example a river, or changes over time, by visualizing the passing of time in an animated movie. References: van Loon, A.F., Laaha, G.: Hydrological drought severity explained by climate and catchment characteristics, Journal of Hydrology 526, 3-14, 2015, Drought processes, modeling, and mitigation Stoll, S., Hendricks Franssen, H. J., Barthel, R., Kinzelbach, W.: What can we learn from long-term groundwater data to improve climate change impact studies?, Hydrology and Earth System Sciences 15(12), 3861-3875, 2011
Random matrices as models for the statistics of quantum mechanics
Casati, Giulio; Guarneri, Italo; Mantica, Giorgio
1986-05-01
Random matrices from the Gaussian unitary ensemble generate in a natural way unitary groups of evolution in finite-dimensional spaces. The statistical properties of this time evolution can be investigated by studying the time autocorrelation functions of dynamical variables. We prove general results on the decay properties of such autocorrelation functions in the limit of infinite-dimensional matrices. We discuss the relevance of random matrices as models for the dynamics of quantum systems that are chaotic in the classical limit. Permanent address: Dipartimento di Fisica, Via Celoria 16, 20133 Milano, Italy.
On the asymptotic distribution of block-modified random matrices
Energy Technology Data Exchange (ETDEWEB)
Arizmendi, Octavio, E-mail: octavius@cimat.mx [Department of Probability and Statistics, CIMAT, Guanajuato (Mexico); Nechita, Ion, E-mail: nechita@irsamc.ups-tlse.fr [Zentrum Mathematik, M5, Technische Universität München, Boltzmannstrasse 3, 85748 Garching, Germany and CNRS, Laboratoire de Physique Théorique, IRSAMC, Université de Toulouse, UPS, F-31062 Toulouse (France); Vargas, Carlos, E-mail: obieta@math.tugraz.at [Department of Mathematical Structure Theory, Technische Universität Graz, Steyrergasse 30/III, 8010 Graz (Austria)
2016-01-15
We study random matrices acting on tensor product spaces which have been transformed by a linear block operation. Using operator-valued free probability theory, under some mild assumptions on the linear map acting on the blocks, we compute the asymptotic eigenvalue distribution of the modified matrices in terms of the initial asymptotic distribution. Moreover, using recent results on operator-valued subordination, we present an algorithm that computes, numerically but in full generality, the limiting eigenvalue distribution of the modified matrices. Our analytical results cover many cases of interest in quantum information theory: we unify some known results and we obtain new distributions and various generalizations.
Kerov's interlacing sequences and random matrices
Energy Technology Data Exchange (ETDEWEB)
Bufetov, Alexey, E-mail: alexey.bufetov@gmail.com [Institute for Information Transmission Problems, Independent University of Moscow and Higher School of Economics, Moscow (Russian Federation)
2013-11-15
To a N × N real symmetric matrix Kerov assigns a piecewise linear function whose local minima are the eigenvalues of this matrix and whose local maxima are the eigenvalues of its (N − 1) × (N − 1) submatrix. We study the scaling limit of Kerov's piecewise linear functions for Wigner and Wishart matrices. For Wigner matrices the scaling limit is given by the Verhik-Kerov-Logan-Shepp curve which is known from asymptotic representation theory. For Wishart matrices the scaling limit is also explicitly found, and we explain its relation to the Marchenko-Pastur limit spectral law.
ANOVA like analysis for structured families of stochastic matrices
Dias, Cristina; Santos, Carla; Varadinov, Maria; Mexia, João T.
2016-12-01
Symmetric stochastic matrices width a width a dominant eigenvalue λ and the corresponding eigenvector α appears in many applications. Such matrices can be written as M =λ α αt+E¯. Thus β = λ α will be the structure vector. When the matrices in such families correspond to the treatments of a base design we can carry out a ANOVA like analysis of the action of the treatments in the model on the structured vectors. This analysis can be transversal-when we worked width homologous components and - longitudinal when we consider contrast on the components of each structure vector. The analysis will be briefly considered at the end of our presentation.
Lipschitz correspondence between metric measure spaces and random distance matrices
Gadgil, Siddhartha
2011-01-01
Given a metric space with a Borel probability measure, for each integer $N$ we obtain a probability distribution on $N\\times N$ distance matrices by considering the distances between pairs of points in a sample consisting of $N$ points chosen indepenedently from the metric space with respect to the given measure. We show that this gives an asymptotically bi-Lipschitz relation between metric measure spaces and the corresponding distance matrices. This is an effective version of a result of Vershik that metric measure spaces are determined by associated distributions on infinite random matrices.
Institute of Scientific and Technical Information of China (English)
侯素梅
2002-01-01
实矩阵A称为是almostP-矩阵,如果A的行列式是正的,而所有真主子式是负的.本文给出了almostP-矩阵的一些性质以及almostP-矩阵与弱almostP-矩阵之间的关系.%An almost P-matrix A is one with real entries whose determinant is negative and all proper minors are positive. Obtain some properties for almost P-matrices, and the relationship between almost P-matrices and weak almost P-matrices.
User-Friendly Tools for Random Matrices: An Introduction
2012-12-03
The set of positive-semidefinite matrices with size d forms a closed, convex cone in the real- linear space of Hermitian matrices of dimension d...valued function h on matrices that is concave or convex. The expectation of a random matrix can be viewed as a convex combination, and the cone of...hope shatters when we subject it to interrogation. It is not hard to find the reason that (3.3.2) fails. Note that the identity (3.3.1) depends on the
Search for pressure-induced superconductivity in CeFeAsO and CeFePO iron pnictides
Energy Technology Data Exchange (ETDEWEB)
Zocco, D. A. [University of California, San Diego; Baumbach, R. E. [University of California, San Diego; Hamlin, J. J. [University of California, San Diego; Janoschek, M. [University of California, San Diego; Lum, I. K. [University of California, San Diego; McGuire, Michael A [ORNL; Safa-Sefat, Athena [ORNL; Sales, Brian C [ORNL; Jin, Rongying [ORNL; Mandrus, David [ORNL; Jeffries, J. R. [Lawrence Livermore National Laboratory (LLNL); Weir, S. T. [Lawrence Livermore National Laboratory (LLNL); Vohra, Y. K. [University of Alabama, Birmingham; Maple, M. B. [University of California, San Diego
2011-01-01
The CeFeAsO and CeFePO iron pnictide compounds were studied via electrical transport measurements under high pressure. In CeFeAsO polycrystals, the magnetic phases involving the Fe and Ce ions coexist for hydrostatically applied pressures up to 15 GPa, and with no signs of pressure-induced superconductivity up to 50 GPa for the less hydrostatic pressure techniques. For the CeFePO single crystals, pressure further stabilizes the Kondo screening of the Ce 4f-electron magnetic moments.
Automated sample preparation for CE-SDS.
Le, M Eleanor; Vizel, Alona; Hutterer, Katariina M
2013-05-01
Traditionally, CE with SDS (CE-SDS) places many restrictions on sample composition. Requirements include low salt content, known initial sample concentration, and a narrow window of final sample concentration. As these restrictions require buffer exchange for many sample types, sample preparation is often tedious and yields poor sample recoveries. To improve capacity and streamline sample preparation, an automated robotic platform was developed using the PhyNexus Micro-Extractor Automated Instrument (MEA) for both the reduced and nonreduced CE-SDS assays. This automated sample preparation normalizes sample concentration, removes salts and other contaminants, and adds the required CE-SDS reagents, essentially eliminating manual steps during sample preparation. Fc-fusion proteins and monoclonal antibodies were used in this work to demonstrate benefits of this approach when compared to the manual method. With optimized conditions, this application has demonstrated decreased analyst "hands on" time and reduced total assay time. Sample recovery greater than 90% can be achieved, regardless of initial composition and concentration of analyte.
PALACZ, M; SUJKOWSKI, Z; NYBERG, J; BACELAR, J; JONGMAN, J; HESSELINK, W; NASSER, J; PLOMPEN, A; WYSS, R
1991-01-01
Gamma ray spectra from the Sn-117(O-18, 4n)131Ce reaction have been studied with the NORDBALL array of 15 Compton-suppressed Ge detectors. States up to I = 51/2 h, E almost-equal-to 8 MeV are populated. Observed bands are interpreted in terms of quasiparticle configurations.
Flach, Joost; van der Waal, Mark B; van den Nieuwboer, Maurits; Claassen, Eric; Larsen, Olaf F A
2017-06-13
Probiotic microorganisms are increasingly incorporated into food matrices in order to confer proposed health benefits on the consumer. It is important that the health benefits, sensory properties, shelf-life and probiotic gastrointestinal tract (GIT) survival of these products are carefully balanced as they determine functionality and drive consumer acceptance. The strain-specific effects of probiotic species are imperative in this process but carrier matrices may play a pivotal role as well. This study therefore recapitulates the wealth of knowledge on carrier matrices and their interaction with probiotic strains. The most substantiated carrier matrices, factors that influence probiotic functionality and matrix effects on shelf-life, GIT survival and clinical efficacy are reviewed. Results indicate that carrier matrices have a significant impact on the quality of probiotic products. Matrix components, such as proteins, carbohydrates and flavoring agents are shown to alter probiotic efficacy and viability. In vivo studies furthermore revealed strain-dependent matrix effects on the GIT survival of probiotic bacteria. However, only a limited number of studies have specifically addressed the effects of carrier matrices on the aforementioned product-parameters; most studies seem to focus solely on the strain-specific effects of probiotic microorganisms. This hampers the innovation of probiotic products. More human studies, comparing not only different probiotic strains but different carrier matrices as well, are needed to drive the innovation cycle.
Valence state of Ce and the magnetism in CeRh3B2
Malik, S. K.; Umarji, A. M.; Shenoy, G. K.; Montano, P. A.; Reeves, M. E.
1985-04-01
The compound CeRh3B2 orders magnetically with a high Curie temperature (TC) of 115 K but with a low moment of only absorption edge measurements show a dominant absorption peak at the energy corresponding to trivalent cerium. Magnetic studies on the compounds Ce(Rhsub1-xTsubx)sub3Bsub2 with T=Ru and Os reveal that the magnetic state is very rapidly broken up with the replacement of Rh by Ru and Os. These results along with the observation of a high TsubC in CeRhsub3Bsub2 suggest that magnetism in this compound arises from a strong hybridization of nearly localized or slightly delocalized Ce 4f electrons with conduction electrons. The small moment may be due to a Kondo-type interaction coupled with crystal-field effects.
Correlated electronic structure of CeN
Energy Technology Data Exchange (ETDEWEB)
Panda, S.K., E-mail: swarup.panda@physics.uu.se [Department of Physics and Astronomy, Uppsala University, P.O. Box 516, SE-751 20 Uppsala (Sweden); Di Marco, I. [Department of Physics and Astronomy, Uppsala University, P.O. Box 516, SE-751 20 Uppsala (Sweden); Delin, A. [Department of Physics and Astronomy, Uppsala University, P.O. Box 516, SE-751 20 Uppsala (Sweden); KTH Royal Institute of Technology, School of Information and Communication Technology, Department of Materials and Nano Physics, Electrum 229, SE-164 40 Kista (Sweden); KTH Royal Institute of Technology, Swedish e-Science Research Center (SeRC), SE-100 44 Stockholm (Sweden); Eriksson, O., E-mail: olle.eriksson@physics.uu.se [Department of Physics and Astronomy, Uppsala University, P.O. Box 516, SE-751 20 Uppsala (Sweden)
2016-04-15
Highlights: • The electronic structure of CeN is studied within the GGA+DMFT approach using SPTF and Hubbard I approximation. • 4f spectral functions from SPTF and Hubbard I are coupled to explain the various spectroscopic manifestations of CeN. • The calculated XPS and BIS spectra show good agreement with the corresponding experimental spectra. • The contribution of the various l-states and the importance of cross-sections for the photoemission process are analyzed. - Abstract: We have studied in detail the electronic structure of CeN including spin orbit coupling (SOC) and electron–electron interaction, within the dynamical mean-field theory combined with density-functional theory in generalized gradient approximation (GGA+DMFT). The effective impurity problem has been solved through the spin-polarized T-matrix fluctuation-exchange (SPTF) solver and the Hubbard I approximation (HIA). The calculated l-projected atomic partial densities of states and the converged potential were used to obtain the X-ray-photoemission-spectra (XPS) and Bremstrahlung Isochromat spectra (BIS). Following the spirit of Gunnarsson–Schonhammer model, we have coupled the SPTF and HIA 4f spectral functions to explain the various spectroscopic manifestations of CeN. Our computed spectra in such a coupled scheme explain the experimental data remarkably well, establishing the validity of our theoretical model in analyzing the electronic structure of CeN. The contribution of the various l-states in the total spectra and the importance of cross sections are also analyzed in detail.
Positive hysteresis of Ce-doped GAGG scintillator
Yanagida, Takayuki; Fujimoto, Yutaka; Koshimizu, Masanori; Watanabe, Kenichi; Sato, Hiroki; Yagi, Hideki; Yanagitani, Takagimi
2014-10-01
Positive hysteresis and radiation tolerance to high-dose radiation exposure were investigated for Ce 1% and 3% doped Gd3(Al, Ga)5O12 (Ce:GAGG) crystal scintillator on comparison with other garnet scintillators such Ce:YAG, Ce:LuAG, Pr:LuAG, and ceramic Ce:GAGG. When they were irradiated by several Gy 60Co γ-rays, Ce 1% doped GAGG crystal exhibited ∼20% light yield enhancement (positive hysteresis). This is the first time to observe positive hysteresis in Ce doped GAGG. On the other hand, other garnet materials did not show the positive hysteresis and their light yields were stable after 800 Gy irradiation except Pr:LuAG. The light yield of Pr:LuAG decreased largely. When irradiated Ce:GAGG which showed positive hysteresis was evaluated in Synchrotron facility (UVSOR), new excitation band was created around 60 nm.
Corbeil Therrien, Audrey
La tomographie d'emission par positrons (TEP) est un outil precieux en recherche preclinique et pour le diagnostic medical. Cette technique permet d'obtenir une image quantitative de fonctions metaboliques specifiques par la detection de photons d'annihilation. La detection des ces photons se fait a l'aide de deux composantes. D'abord, un scintillateur convertit l'energie du photon 511 keV en photons du spectre visible. Ensuite, un photodetecteur convertit l'energie lumineuse en signal electrique. Recemment, les photodiodes avalanche monophotoniques (PAMP) disposees en matrice suscitent beaucoup d'interet pour la TEP. Ces matrices forment des detecteurs sensibles, robustes, compacts et avec une resolution en temps hors pair. Ces qualites en font un photodetecteur prometteur pour la TEP, mais il faut optimiser les parametres de la matrice et de l'electronique de lecture afin d'atteindre les performances optimales pour la TEP. L'optimisation de la matrice devient rapidement une operation difficile, car les differents parametres interagissent de maniere complexe avec les processus d'avalanche et de generation de bruit. Enfin, l'electronique de lecture pour les matrices de PAMP demeure encore rudimentaire et il serait profitable d'analyser differentes strategies de lecture. Pour repondre a cette question, la solution la plus economique est d'utiliser un simulateur pour converger vers la configuration donnant les meilleures performances. Les travaux de ce memoire presentent le developpement d'un tel simulateur. Celui-ci modelise le comportement d'une matrice de PAMP en se basant sur les equations de physique des semiconducteurs et des modeles probabilistes. Il inclut les trois principales sources de bruit, soit le bruit thermique, les declenchements intempestifs correles et la diaphonie optique. Le simulateur permet aussi de tester et de comparer de nouvelles approches pour l'electronique de lecture plus adaptees a ce type de detecteur. Au final, le simulateur vise a
Aqueous chemistry of Ce(iv): estimations using actinide analogues.
Marsac, Rémi; Réal, Florent; Banik, Nidhu Lal; Pédrot, Mathieu; Pourret, Olivier; Vallet, Valérie
2017-10-10
The prediction of cerium (Ce) aqueous speciation is relevant in many research fields. Indeed, Ce compounds are used for many industrial applications, which may require the control of Ce aqueous chemistry for their synthesis. The aquatic geochemistry of Ce is also of interest. Due to its growing industrial use and its release into the environment, Ce is now considered as an emerging contaminant. Cerium is also used as a proxy of (paleo)redox conditions due to the Ce(iv)/Ce(iii) redox transition. Finally, Ce(iv) is often presented as a relevant analogue of tetravalent actinides (An(iv)). In the present study, quantum chemical calculations were conducted to highlight the similarities between the structures of Ce(iv) and tetravalent actinide (An(iv); An = Th, Pa, U, Np, Pu) aqua-ions, especially Pu(iv). The current knowledge of An(iv) hydrolysis, solubility and colloid formation in water was briefly reviewed but important discrepancies were observed in the available data for Ce(iv). Therefore, new estimations of the hydrolysis constants of Ce(iv) and the solubility of Ce(iv)-(hydr)oxides are proposed, by analogy with Pu(iv). By plotting pH-Eh (Pourbaix) diagrams, we showed that the pH values corresponding to the onset of Ce(iv) species formation (i.e. Ce(iv)-(hydr)oxide or dissolved Ce(iv)) agreed with various experimental results. Although further experimental studies are required to obtain a more accurate thermodynamic database, the present work might yet help to predict more accurately the Ce chemical behavior in aqueous solution.
ON THE STIFFNESS OF DEMINERALIZED DENTIN MATRICES
Ryou, Heonjune; Turco, Gianluca; Breschi, Lorenzo; Tay, Franklin R.; Pashley, David H.; Arola, Dwayne
2015-01-01
Resin bonding to dentin requires the use of self-etching primers or acid etching to decalcify the surface and expose a layer of collagen fibrils of the dentin matrix. Acid-etching reduces the stiffness of demineralized dentin from approximately 19 GPa to 1 MPa, requiring that it floats in water to prevent it from collapsing during bonding procedures. Several publications show that crosslinking agents like gluteraladehyde, carbodiimide or grape seed extract can stiffen collagen and improve resin-dentin bond strength. Objective The objective was to assess a new approach for evaluating the changes in stiffness of decalcified dentin by polar solvents and a collagen cross-linker. Methods Fully demineralized dentin beams and sections of etched coronal dentin were subjected to indentation loading using a cylindrical flat indenter in water, and after treatment with ethanol or ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC). The stiffness was measured as a function of strain and as a function of loading rate from 1 to 50 µm/sec. Results At a strain of 0.25% the elastic modulus of the fully demineralized dentin was approximately 0.20 MPa. It increased to over 0.90 MPa at strains of 1%. Exposure to ethanol caused an increase in elastic modulus of up to four times. Increasing the loading rate from 1 to 50 µm/sec caused an increase in the apparent modulus of up to three times in both water and ethanol. EDC treatment caused increases in the stiffness in fully demineralized samples and in acid-etched demineralized dentin surfaces in situ. Significance Changes in the mechanical behavior of demineralized collagen matrices can be measured effectively under hydration via indentation with cylindrical flat indenters. This approach can be used for quantifying the effects of bonding treatments on the properties of decalcified dentin after acid etching, as well as to follow the loss of stiffness over time due to enzymatic degradation. PMID:26747822
Super Fuzzy Matrices and Super Fuzzy Models for Social Scientists
Kandasamy, W B Vasantha; Amal, K
2008-01-01
This book introduces the concept of fuzzy super matrices and operations on them. This book will be highly useful to social scientists who wish to work with multi-expert models. Super fuzzy models using Fuzzy Cognitive Maps, Fuzzy Relational Maps, Bidirectional Associative Memories and Fuzzy Associative Memories are defined here. The authors introduce 13 multi-expert models using the notion of fuzzy supermatrices. These models are described with illustrative examples. This book has three chapters. In the first chaper, the basic concepts about super matrices and fuzzy super matrices are recalled. Chapter two introduces the notion of fuzzy super matrices adn their properties. The final chapter introduces many super fuzzy multi expert models.
Transfer matrices of dipoles with bending radius variation
Institute of Scientific and Technical Information of China (English)
无
2011-01-01
With the increasing demand of high brightness in light source, the uniform dipole can not meet the needs of low emittance, and thus the dipole with bending radius variation is introduced in this paper. The transfer matrix of a non-uniform dipole whose bending radius is linearly changed is chosen as an example and a very simple calculation formula of non-uniform dipole transfer matrices is given. The transfer matrices of some common profile non-uniform dipoles are also listed. The comparison of these transfer matrices and the matrices calculated with slices method verifies the numerical accuracy of this formula. This method can make the non-uniform beam dynamic problem simpler, very helpful for emittance research and lattice design with non-uniform dipoles.
Systems of Differential Equations with Skew-Symmetric, Orthogonal Matrices
Glaister, P.
2008-01-01
The solution of a system of linear, inhomogeneous differential equations is discussed. The particular class considered is where the coefficient matrix is skew-symmetric and orthogonal, and where the forcing terms are sinusoidal. More general matrices are also considered.
Hopf monoids from class functions on unitriangular matrices
Aguiar, Marcelo; Thiem, Nathaniel
2012-01-01
We build, from the collection of all groups of unitriangular matrices, Hopf monoids in Joyal's category of species. Such structure is carried by the collection of class function spaces on those groups, and also by the collection of superclass function spaces, in the sense of Diaconis and Isaacs. Superclasses of unitriangular matrices admit a simple description from which we deduce a combinatorial model for the Hopf monoid of superclass functions, in terms of the Hadamard product of the Hopf monoids of linear orders and of set partitions. This implies a recent result relating the Hopf algebra of superclass functions on unitriangular matrices to symmetric functions in noncommuting variables. We determine the algebraic structure of the Hopf monoid: it is a free monoid in species, with the canonical Hopf structure. As an application, we derive certain estimates on the number of conjugacy classes of unitriangular matrices.
矩阵逆半群%Inverse Semigroups of Matrices
Institute of Scientific and Technical Information of China (English)
朱用文
2008-01-01
We discuss some fundamental properties of inverse semigroups of matrices, and prove that the idempotents of such a semigroup constitute a subsemilattice of a finite Boolean lattice,and that the inverse semigroups of some matrices with the same rank are groups. At last, we determine completely the construction of the inverse semigroups of some 2 x 2 matrices: such a semigroup is isomorphic to a linear group of dimension 2 or a null-adjoined group, or is afinite semilattice of Abelian linear groups of finite dimension, or satisfies some other properties.The necessary and sufficient conditions are given that the sets consisting of some 2 × 2 matrices become inverse semigroups.
Large deviations of the maximal eigenvalue of random matrices
Borot, Gaëtan; Majumdar, Satya; Nadal, Céline
2011-01-01
We present detailed computations of the 'at least finite' terms (three dominant orders) of the free energy in a one-cut matrix model with a hard edge a, in beta-ensembles, with any polynomial potential. beta is a positive number, so not restricted to the standard values beta = 1 (hermitian matrices), beta = 1/2 (symmetric matrices), beta = 2 (quaternionic self-dual matrices). This model allows to study the statistic of the maximum eigenvalue of random matrices. We compute the large deviation function to the left of the expected maximum. We specialize our results to the gaussian beta-ensembles and check them numerically. Our method is based on general results and procedures already developed in the literature to solve the Pastur equations (also called "loop equations"). It allows to compute the left tail of the analog of Tracy-Widom laws for any beta, including the constant term.
Systems of Differential Equations with Skew-Symmetric, Orthogonal Matrices
Glaister, P.
2008-01-01
The solution of a system of linear, inhomogeneous differential equations is discussed. The particular class considered is where the coefficient matrix is skew-symmetric and orthogonal, and where the forcing terms are sinusoidal. More general matrices are also considered.
Racah matrices and hidden integrability in evolution of knots
Mironov, A; Morozov, An; Sleptsov, A
2016-01-01
We construct a general procedure to extract the exclusive Racah matrices S and \\bar S from the inclusive 3-strand mixing matrices by the evolution method and apply it to the first simple representations R =[1], [2], [3] and [2,2]. The matrices S and \\bar S relate respectively the maps (R\\otimes R)\\otimes \\bar R\\longrightarrow R with R\\otimes (R \\otimes \\bar R) \\longrightarrow R and (R\\otimes \\bar R) \\otimes R \\longrightarrow R with R\\otimes (\\bar R \\otimes R) \\longrightarrow R. They are building blocks for the colored HOMFLY polynomials of arbitrary arborescent (double fat) knots. Remarkably, the calculation realizes an unexpected integrability property underlying the evolution matrices.
Determinant and inverse of join matrices on two sets
Mattila, Mika
2011-01-01
Let $(P,\\preceq)$ be a lattice and $f$ a complex-valued function on $P$. We define meet and join matrices on two arbitrary subsets $X$ and $Y$ of $P$ by $(X,Y)_f=(f(x_i\\wedge y_j))$ and $[X,Y]_f=(f(x_i\\vee x_j))$ respectively. Here we present expressions for the determinant and the inverse of $[X,Y]_f$. Our main goal is to cover the case when $f$ is not semimultiplicative since the formulas presented earlier for $[X,Y]_f$ cannot be applied in this situation. In cases when $f$ is semimultiplicative we obtain several new and known formulas for the determinant and inverse of $(X,Y)_f$ and the usual meet and join matrices $(S)_f$ and $[S]_f$. We also apply these formulas to LCM, MAX, GCD and MIN matrices, which are special cases of join and meet matrices.
Automorphisms of sl(2) and dynamical r-matrices
Tsiganov, A V
1996-01-01
Two outer automorphisms of infinite-dimensional representations of $sl(2)$ algebra are considered. The similar constructions for the loop algebras and yangians are presented. The corresponding linear and quadratic $R$-brackets include the dynamical $r$-matrices.
The Dirac operator and gamma matrices for quantum Minkowski spaces
1997-01-01
Gamma matrices for quantum Minkowski spaces are found. The invariance of the corresponding Dirac operator is proven. We introduce momenta for spin 1/2 particles and get (in certain cases) formal solutions of the Dirac equation.
Synbiotic matrices derived from plant oligosaccharides and polysaccharides
A porous synbiotic matrix was prepared by lyophilization of alginate and pectin or fructan oligosaccharides and polysaccharides cross-linked with calcium. These synbiotic matrices were excellent physical structures to support the growth of Lactobacillus acidophilus (1426) and Lactobacillus reuteri (...
Morphic images of binary words and Parikh matrices
Isawasan, Pradeep; Venkat, Ibrahim; Subramanian, K. G.; Sarmin, Nor Haniza
2014-07-01
A word is a finite sequence of symbols. Parikh matrix of a word, introduced by Mateescu et al (2000), has become an effective tool in the study of certain numerical properties of words based on subwords. There have been several investigations on various properties of Parikh matrices such as M-ambiguity, M-equivalence, subword equalities and inequalities, commutativity and so on. Recently, Parikh matrices of words that are images under certain morphisms have been studied for their properties. On the other hand, Parikh matrices of words involving a certain ratio property called weak-ratio property have been investigated by Subramanian et al (2009). Here we consider two special morphisms called Fibonacci and Tribonacci morphisms and obtain properties of Parikh matrices of images of binary words under these morphisms, utilizing the notion of weak-ratio property.
Van Koetsem, Frederik; Xiao, Yi; Luo, Zhuanxi; Du Laing, Gijs
2016-03-01
In this study, the potential association of (citrate-stabilized) Ag (14.1 ± 1.0 nm) and CeO2 (6.7 ± 1.2 nm) engineered nanoparticles (ENPs), or their ionic counterparts, with the submerged aquatic plant Elodea canadensis, was examined and, in particular, parameters affecting the distribution of the nanoparticles (or metal ions) between plant biomass and the water phase were assessed using five distinct aqueous matrices (i.e. tap water, 10 % Hoagland's solution and three natural surface water samples). Individual plants were exposed to varying concentrations of Ag and CeO2 ENPs or Ag(+) and Ce(3+) ions during 72-h-lasting batch experiments. A dose-dependent increase of silver or cerium in plant biomass was observed for both the nanoparticles and the ions, whereby exposure to the latter systematically resulted in significantly higher biomass concentrations. Furthermore, the apparent plant uptake of CeO2 ENPs appeared to be higher than that for Ag ENPs when comparing similar exposure concentrations. These findings suggest that association with E. canadensis might be affected by particle characteristics such as size, composition, surface charge or surface coating. Moreover, the stability of the ENPs or ions in suspension/solution may be another important aspect affecting plant exposure and uptake. The association of the nanoparticles or ions with E. canadensis was affected by the physicochemical characteristics of the water sample. The silver biomass concentration was found to correlate significantly with the electrical conductivity (EC), dry residue (DR) and Cl(-), K, Na and Mg content in the case of Ag ENPs or with the EC, inorganic carbon (IC) and Cl(-), NO3 (-), Na and Mg content in the case of Ag(+) ions, whereas significant relationships between the cerium biomass concentration and the EC, DR, IC and Ca content or the pH, EC, DR, IC and Cl(-), Ca and Mg content were obtained for CeO2 ENPs or Ce(3+) ions, respectively. Results also indicated that the Ag
cDNA library Table: ce-- [KAIKOcDNA[Archive
Lifescience Database Archive (English)
Full Text Available ce-- NA ce-- C202 x J201 compound eyes mixture of fifth instar larval stage to pupa...l stage mixed pBluescript SK- EcoR1 for 5' Xho1for 3' sequenced from T3 primer (5' -> 3') BP117205-BP118782 ce--[number] ...
A SURVEY ON SEMI-TENSOR PRODUCT OF MATRICES
Institute of Scientific and Technical Information of China (English)
Daizhan CHENG; Hongsheng QI; Ancheng XUE
2007-01-01
Semi-tensor product of matrices is a generalization of conventional matrix product for the case when the two factor matrices do not meet the dimension matching condition. It was firstly proposed about ten years ago. Since then it has been developed and applied to several different fields.In this paper we will first give a brief introduction. Then give a survey on its applications to dynamic systems, to logic, to differential geometry, to abstract algebra, respectively.
Maximum-likelihood estimation prevents unphysical Mueller matrices
Aiello, A; Voigt, D; Woerdman, J P
2005-01-01
We show that the method of maximum-likelihood estimation, recently introduced in the context of quantum process tomography, can be applied to the determination of Mueller matrices characterizing the polarization properties of classical optical systems. Contrary to linear reconstruction algorithms, the proposed method yields physically acceptable Mueller matrices even in presence of uncontrolled experimental errors. We illustrate the method on the case of an unphysical measured Mueller matrix taken from the literature.
Embedding cocyclic D-optimal designs in cocyclic Hadamard matrices
Álvarez, Víctor; Frau, María-Dolores; Gudiel, Félix
2012-01-01
In this paper a method for embedding cocyclic submatrices with ``large'' determinants of orders 2t in certain cocyclic Hadamard matrices of orders 4t is described (t an odd integer). If these determinants attain the largest possible value, we are embedding D-optimal designs. Applications to the pivot values that appear when Gaussian Elimination with complete pivoting is performed on these cocyclic Hadamard matrices are studied.
An introduction to the theory of canonical matrices
Turnbull, H W
2004-01-01
Thorough and self-contained, this penetrating study of the theory of canonical matrices presents a detailed consideration of all the theory's principal features. Topics include elementary transformations and bilinear and quadratic forms; canonical reduction of equivalent matrices; subgroups of the group of equivalent transformations; and rational and classical canonical forms. The final chapters explore several methods of canonical reduction, including those of unitary and orthogonal transformations. 1952 edition. Index. Appendix. Historical notes. Bibliographies. 275 problems.
Remarks on a one-parameter family of singular matrices
Sharma, Ramesh; Pariso, Chris; Duda, Michelle
2015-01-01
This short article will present to the reader a family of matrices that form an algebra over the reals. This presentation provides both current and former students of modern abstract algebra a better illustration of the concepts of rings, fields, and algebra itself. In addition, this article relates eigenspaces of 3×3 matrices with the arithmetic-geometric mean equality, an attribute that teachers might enjoy utilizing as a teaching tool in their classes.
Local Law of Addition of Random Matrices on Optimal Scale
Bao, Zhigang; Erdős, László; Schnelli, Kevin
2016-11-01
The eigenvalue distribution of the sum of two large Hermitian matrices, when one of them is conjugated by a Haar distributed unitary matrix, is asymptotically given by the free convolution of their spectral distributions. We prove that this convergence also holds locally in the bulk of the spectrum, down to the optimal scales larger than the eigenvalue spacing. The corresponding eigenvectors are fully delocalized. Similar results hold for the sum of two real symmetric matrices, when one is conjugated by Haar orthogonal matrix.
Boundary transfer matrices and boundary quantum KZ equations
Energy Technology Data Exchange (ETDEWEB)
Vlaar, Bart, E-mail: Bart.Vlaar@nottingham.ac.uk [School of Mathematical Sciences, University of Nottingham, Nottingham NG7 2RD (United Kingdom)
2015-07-15
A simple relation between inhomogeneous transfer matrices and boundary quantum Knizhnik-Zamolodchikov (KZ) equations is exhibited for quantum integrable systems with reflecting boundary conditions, analogous to an observation by Gaudin for periodic systems. Thus, the boundary quantum KZ equations receive a new motivation. We also derive the commutativity of Sklyanin’s boundary transfer matrices by merely imposing appropriate reflection equations, in particular without using the conditions of crossing symmetry and unitarity of the R-matrix.
A method of diagonalization for sfermion mass matrices
Aranda, Alfredo; Noriega-Papaqui, R
2009-01-01
We present a method of diagonalization for the sfermion mass matrices of the minimal supersymmetric standard model (MSSM). It provides analytical expressions for the masses and mixing angles of rather general hermitian sfermion mass matrices, and allows the study of scenarios that extend the usual constrained - MSSM. Three signature cases are presented explicitly and a general study of flavor changing neutral current processes is outlined in the discussion.
Procrustes Problems for General, Triangular, and Symmetric Toeplitz Matrices
Directory of Open Access Journals (Sweden)
Juan Yang
2013-01-01
Full Text Available The Toeplitz Procrustes problems are the least squares problems for the matrix equation AX=B over some Toeplitz matrix sets. In this paper the necessary and sufficient conditions are obtained about the existence and uniqueness for the solutions of the Toeplitz Procrustes problems when the unknown matrices are constrained to the general, the triangular, and the symmetric Toeplitz matrices, respectively. The algorithms are designed and the numerical examples show that these algorithms are feasible.
Moment Matrices, Border Bases and Real Radical Computation
Lasserre, Jean-Bernard; Laurent, Monique; Mourrain, Bernard; Rostalski, Philipp; Trébuchet, Philippe
2013-01-01
International audience; In this paper, we describe new methods to compute the radical (resp. real radical) of an ideal, assuming it complex (resp. real) variety is finite. The aim is to combine approaches for solving a system of polynomial equations with dual methods which involve moment matrices and semi-definite programming. While the border basis algorithms of [17] are efficient and numerically stable for computing complex roots, algorithms based on moment matrices [12] allow the incorpora...
Preliminary Analysis on Matric Suction for Barren Soil
Azhar, A. T. S.; Fazlina, M. I. S.; Aziman, M.; Fairus, Y. M.; Azman, K.; Hazreek, Z. A. M.
2016-11-01
Most research conducted on slope failures can broadly be attributed to the convergence of three factors, i.e. rainfall, steepness of slope, and soil geological profile. The mechanism of the failures is mainly due to the loss of matric suction of soils by rainwater. When rainwater infiltrates into the slopes, it will start to saturate the soil, i.e., reduce the matric suction. A good understanding of landslide mechanisms and the characteristics of unsaturated soil and rock in tropical areas is crucial in landslide hazard formulation. Most of the slope failures in unsaturated tropical residual soil in Malaysia are mainly due to infiltration, especially during intense and prolonged rainfall, which reduces the soil matric suction and hence decreases the stability of the slope. Therefore, the aim of this research is to determine the matric suction for barren soil and to model an unsaturated slope with natural rainfall to evaluate the effects of matric suction on rainfall intensity. A field test was carried out using the Watermark Soil Moisture Sensor to determine the matric suction. The sensor was connected to a program called SpecWare 9 Basic which also used Data Logging Rain gauge Watermark 1120 to measure the intensity and duration of rainfall. This study was conducted at the Research Centre for Soft Soil which is a new Research and Development (R & D) initiative by Universiti Tun Hussein Onn Malaysia, Parit Raja. Field observation showed that the highest daily suction was recorded during noon while the lowest suction was obtained at night and early morning. The highest matric suction for loose condition was 31.0 kPa while the highest matric suction for compacted condition was 32.4 kPa. The results implied that the field suction variation was not only governed by the rainfall, but also the cyclic evaporation process. The findings clearly indicated that the changes in soil suction distribution patterns occurred due to different weather conditions.
Effect of CeO2 on the Property of Zn-Ni/CeO2 Composite Coating%CeO2对Zn-Ni/CeO2复合镀层的影响
Institute of Scientific and Technical Information of China (English)
郑振; 李宁; 黎德育; 孟繁宇
2012-01-01
采用电沉积方法,通过向镀液中加入不同粒径的CeO2颗粒,制得Zn-Ni/微米CeO2复合镀层和Zn-Ni/纳米CeO2复合镀层,研究了CeO2粒子的大小和加入量对镀层微观形貌、相组成、CeO2在镀层中的复合量以及镀层耐蚀性的影响.结果表明:大量加入CeO2,可使镀层呈现块状的“饼干”结构,并能提高镀层的耐蚀性,此外还可以抑制Ni的沉积,加入10 g/L纳米CeO2时,镀层的合金相主要为Ni2Zn11相,其它Zn-Ni合金相则较少;相比之下,在提高镀层CeO2复合量方面,微米级CeO2效果较好,在提高镀层耐蚀性方面,纳米级CeO2的效果较好.%The Ni-Zn/micro-CeO2 composite material and Ni-Zn/nano-CeO2 composite material were produced by electrodeposition method through adding micro- and nano-CeO2 particles in the Zn-Ni plating bath. The effects of the diameter and the concentration of the CeO2 particles on the microtopography, phase component, CeO2 content and the corrosion resistance of the Ni-Zn coating were studied. The result shows that when the concentration of the CeO2 particles is high, the Ni deposition is inhibited; The composite coatings are characterized with laminate morphology with good corrosion resistance. When the concentration of the nano-CeO2 particles is 10 g/L, the major alloy phase is Ni2Zn11. Compared with the nano-composite coating, the CeO2 content is larger in the micro-CeO2 composite coating. But the corrosion resistance of the nano-CeO2 composite coating is larger than that of the micro-CeO2 ones.
Inference for High-dimensional Differential Correlation Matrices.
Cai, T Tony; Zhang, Anru
2016-01-01
Motivated by differential co-expression analysis in genomics, we consider in this paper estimation and testing of high-dimensional differential correlation matrices. An adaptive thresholding procedure is introduced and theoretical guarantees are given. Minimax rate of convergence is established and the proposed estimator is shown to be adaptively rate-optimal over collections of paired correlation matrices with approximately sparse differences. Simulation results show that the procedure significantly outperforms two other natural methods that are based on separate estimation of the individual correlation matrices. The procedure is also illustrated through an analysis of a breast cancer dataset, which provides evidence at the gene co-expression level that several genes, of which a subset has been previously verified, are associated with the breast cancer. Hypothesis testing on the differential correlation matrices is also considered. A test, which is particularly well suited for testing against sparse alternatives, is introduced. In addition, other related problems, including estimation of a single sparse correlation matrix, estimation of the differential covariance matrices, and estimation of the differential cross-correlation matrices, are also discussed.
Local character of the highest antiferromagnetic Ce-system CeTi{1-x}Sc{x} Ge
2014-01-01
The highest antiferromagnetic (AFM) temperature in Ce based compounds has been reported for CeScGe with Tn=47K, but its local or itinerant nature was not deeply investigated yet. In order to shed more light into this unusually high ordering temperature we have investigated structural, magnetic, transport and thermal properties of CeTi{1-x}Sc{x}Ge alloys within the range of stability of the CeScSi-type structure: 0.25
INCA-CE project: status and results
Strauss, Franziska; Meirold-Mautner, Ingo; Bica, Benedikt; Kann, Alexander; Wang, Yong
2013-04-01
Every year, Central Europe (CE) is affected by weather extremes challenging civil protection authorities, hydrologists and road maintenance services to timely warnings. Within the INCA-CE project (Integrated Nowcasting through Comprehensive Analysis in Central Europe; http://www.inca-ce.eu) which is supported by the European Regional Development Fund a deepened transnational cooperation between meteorological/hydrological services and three application areas is established. This guarantees for both enhancements of meteorological products in the sense of end-user friendliness, and standardized information exchange across borders. At present, INCA-CE is the only project throughout the world which connects cooperation to such an extent with respect to its transnational and multidisciplinary framework (in the meanwhile it has been chosen as World Weather Research Programme/Forecast Demonstration Project by the World Meteorological Organization). Key partners from eight countries (from national meteorological/hydrological services and the three different application areas) accept the challenge to work on standardization and harmonization tools. Therefore, the INCA nowcasting system - developed at the Austrian weather service (ZAMG) in the 1990ies - has been implemented at all CE meteorological/hydrological services and is advanced and refined to the specific user needs to (i) provide high quality nowcasting products which are standardized and harmonized across borders, (ii) improve information chains from models to warnings and protection measures in case of disaster, and (iii) make the public and stakeholders more familiar with meteorological products. However, the potential to achieve these listed improvements is only possible through the intense transnational and multidisciplinary cooperation, because for one institution and one country alone it would be impossible to cope with all the necessary tasks. In this presentation the status and results of the INCA-CE
Estimated correlation matrices and portfolio optimization
Pafka, Szilárd; Kondor, Imre
2004-11-01
Correlations of returns on various assets play a central role in financial theory and also in many practical applications. From a theoretical point of view, the main interest lies in the proper description of the structure and dynamics of correlations, whereas for the practitioner the emphasis is on the ability of the models to provide adequate inputs for the numerous portfolio and risk management procedures used in the financial industry. The theory of portfolios, initiated by Markowitz, has suffered from the “curse of dimensions” from the very outset. Over the past decades a large number of different techniques have been developed to tackle this problem and reduce the effective dimension of large bank portfolios, but the efficiency and reliability of these procedures are extremely hard to assess or compare. In this paper, we propose a model (simulation)-based approach which can be used for the systematical testing of all these dimensional reduction techniques. To illustrate the usefulness of our framework, we develop several toy models that display some of the main characteristic features of empirical correlations and generate artificial time series from them. Then, we regard these time series as empirical data and reconstruct the corresponding correlation matrices which will inevitably contain a certain amount of noise, due to the finiteness of the time series. Next, we apply several correlation matrix estimators and dimension reduction techniques introduced in the literature and/or applied in practice. As in our artificial world the only source of error is the finite length of the time series and, in addition, the “true” model, hence also the “true” correlation matrix, are precisely known, therefore in sharp contrast with empirical studies, we can precisely compare the performance of the various noise reduction techniques. One of our recurrent observations is that the recently introduced filtering technique based on random matrix theory performs
Inorganic Nanoparticle Nucleation on Polymer Matrices
Kosteleski, Adrian John
dressing applications. PAA's ability to nucleate nanoparticles in a solid matrix was displayed. Interestingly enough PAA retains its ability to nucleate nanoparticle even when its reactive functional groups are used in the crosslinking process. Silver nanoparticle composition and size on the solid polymer matrices was controlled by varying the composition of PAA. PAA and silver nanoparticles effect on the mechanical properties of the calcium alginate hydrogels were also studied. Physically crosslinking PAA with calcium alginate gels enables the development of intricate gel structures that are decorated with nucleated silver; yielding a composite biomaterial with improved and enhanced antimicrobial properties.
On the Eigenvalues and Eigenvectors of Block Triangular Preconditioned Block Matrices
Pestana, Jennifer
2014-01-01
Block lower triangular matrices and block upper triangular matrices are popular preconditioners for 2×2 block matrices. In this note we show that a block lower triangular preconditioner gives the same spectrum as a block upper triangular preconditioner and that the eigenvectors of the two preconditioned matrices are related. © 2014 Society for Industrial and Applied Mathematics.
CMV matrices in random matrix theory and integrable systems: a survey
Energy Technology Data Exchange (ETDEWEB)
Nenciu, Irina [Courant Institute, 251 Mercer St, New York, NY 10012 (United States)
2006-07-14
We present a survey of recent results concerning a remarkable class of unitary matrices, the CMV matrices. We are particularly interested in the role they play in the theory of random matrices and integrable systems. Throughout the paper we also emphasize the analogies and connections to Jacobi matrices.
Laser properties of yag: Nd, Cr, Ce
Kvapil, J.; Kvapil, Jos; Perner, B.; Kubelka, J.; Mánek, B.; Kubeček, V.
1984-06-01
Transient absorption of a long lifetime (≧ 20 s) of YAG: Nd is typical of pure material. It is the main reason of thermal deformation of the laser rods accompanied with power decreases at higher CW input. It may be prevented by an admixture of Fe, Ti or Cr. Using a small admixture (≦ 10-3 wt.%) of Ti or Cr the energy transfer among Nd ions and the gain coefficient may be increased. Cr in a higher concentration absorbs the pumping light and serves as earlier described coactivator (sensitizer) only. Fe impurity fully prevents any increase of the gain of YAG: Nd containing Ti or Cr and causes slow but irreversible degradation of the active parameters. Ce favourably modifies properties of YAG: Nd, Cr. YAG: Nd, Cr, Ce free of iron impurity is advisable active material for powerfull CW lasers.
Cerium intermetallics CeTX. Review III
Energy Technology Data Exchange (ETDEWEB)
Poettgen, Rainer; Janka, Oliver [Muenster Univ. (Germany). Inst. fuer Anorganische und Analytische Chemie; Chevalier, Bernard [Bordeaux Univ., Pessac (France). Inst. de Chimie de la Matiere Condensee de Bordeaux
2016-05-01
The structure-property relationships of CeTX intermetallics with structures other than the ZrNiAl and TiNiSi type are systematically reviewed. These CeTX phases form with electron-poor and electron-rich transition metals (T) and X = Mg, Zn, Cd, Hg, Al, Ga, In, Tl, Si, Ge, Sn, Pb, P, As, Sb, and Bi. The review focusses on the crystal chemistry, the chemical bonding peculiarities, and the magnetic and transport properties. Furthermore {sup 119}Sn Moessbauer spectroscopic data, high-pressure studies, hydrogenation reactions and the formation of solid solutions are reviewed. This paper is the third of a series of four reviews on equiatomic intermetallic cerium compound [Part I: R. Poettgen, B. Chevalier, Z. Naturforsch. 2015, 70b, 289; Part II: R. Poettgen, B. Chevalier, Z. Naturforsch. 2015, 70b, 695].
Ce qui se passe dans tes doigts
Quintans, Santiago; Lähdeoja, Otso
2010-01-01
Une question simple, c’est quoi la guitare électrique ? Claude Pavy : C’est une planche avec un manche, des cordes qui font tzing, des micros qui captent tzing, et après on fait joujou avec ça. La guitare électrique c’est d’abord le son. Je dis souvent à mes élèves : « la guitare, cela ne m’intéresse pas ». Alors évidemment, ils me regardent avec des yeux ronds, et ils me disent, « T’es guitariste ? » Oui, mais la guitare en elle-même, cela ne m’intéresse pas. Ce qui m’intéresse, c’est ce qu...
Albert-Aguilar, Alexandre; Delmotte, Pauline; André, François; Brissebrat, Guillaume; Canonici, Jean-Christophe; Piguet, Bruno
2016-04-01
SAFIRE is the French facility dedicated to airborne measurement for environmental research. The SAFIRE steering committee decided that access to its archives should be improved. If certain data, including recent campaigns, are available online, access to them is difficult for users because these data are dispersed in as many data portals as campaigns. Most of projects are not able to keep medium to long term online access to their database. Therefore, many airborne data, particularly the oldest, are not available online, stored on media whose sustainability is not guaranteed. SAFIRE also decided to identify old data stored in Meudon (France) on paper and hard media and to rescue with the help of an archivist. At the same time, the development of a centralized digital archive - containing data collected with the Fokker - 27 " ARAT " and Merlin IV aircraft - associated to a web portal was given to SEDOO. The first part of the project consisted in modelling the database. The second part, still in progess, was the development of the CeDRES (Centre de Données aéRoportées & SAFIRE) portal (http://cedres.sedoo.fr) which is responsive and bilingual (French and English) ; and metadata standardization (iso 19115). The main objectives of this project are data preservation and open data access. A first test version of CeDRES portal will be release in mid-February 2016. And operational version is planned for summer 2016. In the future, CeDRES portal will be able to receive and to distribute metadata and data of aircraft currently in service (FALCON-20, ATR-42 and PiperAztec-23). The interoperability implementation and data homogenization are planned in the medium term. The CeDRES portal is part of the French atmospheric chemistry data center AERIS (http://www.aeris-data.fr). Every scientist is invited to browse the catalog and use CEDRES data. Feel free to contact cedres-contact@sedoo.fr for any question.
Enzyme-mimetic activity of Ce-intercalated titanate nanosheets.
Kamada, Kai; Soh, Nobuaki
2015-04-23
Colloidal solutions of Ce-doped titanate nanosheets (Ce-TNS) with tiny dimensions (Ce(NO3)3, and their annihilation activity for reactive oxygen species (ROS) was investigated. The obtained Ce-TNS had an akin crystal structure to layered tetratitanate (Ti4O9(2-)) and Ce ions occupied interlayer space between the host layers with a negative charge. The Ce-TNS possessed a superoxide dismutase (SOD) mimetic activity for disproportionation of superoxide anion radicals (O2(-)) as target ROS. It was explained that the annihilation of O2(-) caused a valence fluctuation of Ce ions existing in the interlayer. Moreover, the activity of Ce-TNS exceeded that of CeO2 nanoparticles recently attracting much attention as an inorganic SOD mimic. The superior performance was explained mainly by a high dispersion stability of the Ce-TNS bringing about a huge reaction area. Moreover, the Ce-TNS protected DNA molecules from ultraviolet light induced oxidative damage, demonstrating effectiveness as one of the new inorganic protecting agents for biomolecules and tissues.
Structure and antibacterial activity of Ce~(3+) exchanged montmorillonites
Institute of Scientific and Technical Information of China (English)
OUYANG Yousheng; XIE Yushan; TAN Shaozao; SHI Qingshan; CHEN Yiben
2009-01-01
Four kinds of Ce~(3+) exchanged montmorillonites(Ce/MMTs) were prepared by an ion-exchange reaction, and characterized with energy dispersive X-ray analysis (EDX), X-ray difference (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron micros-copy (SEM). The surface properties and antibacterial activity of Ce/MMTs were also investigated. The chemical compositions of Ce/MMTs were determined, and the cerium of Ce/MMTs was confirmed to be present as trivalent cerium state. The d001 basal spacings of Ce/MMTs were enlarged with the enhancement of the cerium contents, and the particles were formed with irregular shape. On increasing the Ce con-tents of Ce/MMTs, the special surface areas were decreased, but the total pore volumes and the average pore sizes were increased. The anti-bacterial activity of Ce/MMTs is increased with increasing the cerium contents, and 1.5g/L of Ce/MMT-3 containing 11.46wt.% of curium could remove all the Staphylococcus aureus and more than 99.9% of the Escherichia coli within 24.0 h of contact. Moreover, Ce/MMTs dis-played bactericidal activity.
Preparation and characterization of CNT-CeO2 nanocomposite
Kaur, Jasmeet; Anand, Kanika; Singh, Ravi Chand
2015-06-01
This paper reports decoration of CeO2 nanoparticles on multi-walled carbon nanotubes through a reflux process in which Ce (NO3) 3.6H2O serves as precursor and hydrazine hydrate (N2H4.H2O) as reducing agent. Successful deposition of cubic fluorite CeO2 nanoparticles onto multi-walled carbon nanotubes has been confirmed by x-ray diffraction (XRD), Raman spectroscopy, field-emission scanning electron microscopy (FE-SEM) and energy dispersive x-ray spectroscopy (EDS). It was found that CeO2 nanoparticles formed in the presence of CNTs were larger as compared to pure CeO2 nanoparticles. Raman analysis showed that CeO2 induced a decrease in the size of the carbon grain in the CNTs. A red shift from 460 cm-1 to 463 cm-1 for F2g mode of CeO2 has also been observed in Raman spectra of CNT- CeO2 nanocomposite as compared to pure CeO2. The CeO2 coated multi-wall carbon nanotubes (CNT-CeO2) nanocomposite would be a promising candidate for practical applications such as catalysis, sensing and power source applications.
Durero, M.; Vivier, M.; Agostini, M.; Altenmüller, K.; Appel, S.; Bellini, G.; Benziger, J.; Berton, N.; Bick, D.; Bonfini, G.; Bravo, D.; Caccianiga, B.; Calaprice, F.; Caminata, A.; Cavalcante, P.; Chepurnov, A.; Choi, K.; Cribier, M.; D'Angelo, D.; Davini, S.; Derbin, A.; Di Noto, L.; Drachnev, I.; Etenko, A.; Farinon, S.; Fischer, V.; Fomenko, K.; Franco, D.; Gabriele, F.; Gaffiot, J.; Galbiati, C.; Ghiano, C.; Giammarchi, M.; Goeger-Neff, M.; Goretti, A.; Gromov, M.; Hagner, C.; Houdy, T.; Hungerford, E.; Ianni, Aldo; Ianni, Andrea; Jonqueres, N.; Jedrzejczak, K.; Kaiser, M.; Kobychev, V.; Korablev, D.; Korga, G.; Kornoukhov; Kryn, D.; Lachenmaier, T.; Lasserre, T.; Laubenstein, M.; Lehnert, B.; Link, J.; Litvinovich, E.; Lombardi, F.; Lombardi, P.; Ludhova, L.; Lukyanchenko, G.; Machulin, I.; Manecki, S.; Maneschg, W.; Marcocci, S.; Maricic, J.; Mention, G.; Meroni, E.; Meyer, M.; Miramonti, L.; Misiaszek, M.; Montuschi, M.; Muratova, V.; Musenich, R.; Neumair, B.; Oberauer, L.; Obolensky, M.; Ortica, F.; Pallavicini, M.; Papp, L.; Perasso, L.; Pocar, A.; Ranucci, G.; Razeto, A.; Re, A.; Romani, A.; Roncin, R.; Rossi, N.; Schönert, S.; Scola, L.; Semenov, D.; Simgen, H.; Skorokhvatov, M.; Smirnov, O.; Sotnikov, A.; Sukhotin, S.; Suvorov; Tartaglia, R.; Testera, G.; Thurn, J.; Toropova, M.; Veyssiére, C.; Unzhakov, E.; Vogelaar, R. B.; von Feilitzsch, F.; Wang, H.; Weinz, S.; Winter, J.; Wojcik, M.; Wurm, M.; Yokley, Z.; Zaimidoroga, O.; Zavatarelli, S.; Zuber, K.; Zuzel, G.
2016-02-01
The SOX (Short distance neutrino Oscillations with BoreXino) project aims at testing the light sterile neutrino hypothesis. To do so, two artificials sources of antineutrinos and neutrinos respectively will be consecutively deployed at the Laboratori Nazionali del Gran Sasso (LNGS) in close vicinity to Borexino, a large liquid scintillator detector. This document reports on the source production and transportation. The source should exhibit a long lifetime and a high decay energy, a requirement fullfilled by the 144Ce-144Pr pair at secular equilibrium. It will be produced at FSUE “Mayak” PA using spent nuclear fuel. It will then be shielded and packed according to international regulation and shipped to LNGS across Europe. Knowledge of the Cerium antineutrino generator (CeANG) parameters is crucial for SOX as it can strongly impact the experiment sensitivity. Several apparatuses are being used or designed to characterize CeANG activity, radioactive emission and content. An overview of the measurements performed so far is presented here.
Wang, Fang; Guo, Weil; Ma, Peng-kun; Pan, Liang; Zhang, Jun
2016-01-15
A greenhouse pot experiment was conducted to investigate the effects of arbuscular mycorrhizal (AM) fungi Glomus aggregatum (GA) and Funneliformis mosseae (FM) on AM colonization rate, biomass, nutrient uptake, C: N: P stoichiometric and Ce uptake and transport by maize (Zea mays L.) grown in soils with different levels of Ce-contaminated (100, 500 and 1000 mg x kg(-1)). The aim was to provide basic data and technical support for the treatment of soils contaminated by rare earth elements. The results indicated that symbiotic associations were successfully established between the two isolates and maize, and the average AM colonization rate ranged from 7. 12% to 74.47%. The increasing concentration of Ce in soils significantly decreased the mycorrhizal colonization rate, biomass, nutrition contents and transport rate of Ce from root to shoot of maize, and significantly increased C: P and N: P ratios and Ce contents in shoot and root of maize. Both AM fungi inoculations promoted the growth of maize, but the promoting role of FM was more significant than that of GA in severe Ce-contaminated soils. There were no significant differences in the growth of maize between two AM fungi in mild and moderate Ce-contaminated soils. Inoculation with AM fungi significantly improved nutritional status of maize by increasing nutrient uptake and decreasing C: N: P ratios. GA was more efficient than FM in enhancing nutrient uptake in mild and moderate Ce-contaminated soils, while FM was more efficient in severe Ce-contaminated soils. Moreover, inoculation with AM fungi significantly increased Ce contents of shoot and root in mild Ce-contaminated soils, but had no significant effect on Ce contents of maize in moderate and severe Ce-contaminated soils, and promoted the transport of Ce from root to shoot. The experiment demonstrates that AM fungi can alleviate toxic effects of Ce on plants and have a potential role in the phytoremediation of soils contaminated by rare earth elements.
Retinal pigment epithelium cell alignment on nanostructured collagen matrices.
Ulbrich, Stefan; Friedrichs, Jens; Valtink, Monika; Murovski, Simo; Franz, Clemens M; Müller, Daniel J; Funk, Richard H W; Engelmann, Katrin
2011-01-01
We investigated attachment and migration of human retinal pigment epithelial cells (primary, SV40-transfected and ARPE-19) on nanoscopically defined, two-dimensional matrices composed of parallel-aligned collagen type I fibrils. These matrices were used non-cross-linked (native) or after riboflavin/UV-A cross-linking to study cell attachment and migration by time-lapse video microscopy. Expression of collagen type I and IV, MMP-2 and of the collagen-binding integrin subunit α(2) were examined by immunofluorescence and Western blotting. SV40-RPE cells quickly attached to the nanostructured collagen matrices and aligned along the collagen fibrils. However, they disrupted both native and cross-linked collagen matrices within 5 h. Primary RPE cells aligned more slowly without destroying either native or cross-linked substrates. Compared to primary RPE cells, ARPE-19 cells showed reduced alignment but partially disrupted the matrices within 20 h after seeding. Expression of the collagen type I-binding integrin subunit α(2) was highest in SV40-RPE cells, lower in primary RPE cells and almost undetectable in ARPE-19 cells. Thus, integrin α(2) expression levels directly correlated with the degree of cell alignment in all examined RPE cell types. Specific integrin subunit α(2)-mediated matrix binding was verified by preincubation with an α(2)-function-blocking antibody, which impaired cell adhesion and alignment to varying degrees in primary and SV40-RPE cells. Since native matrices supported extended and directed primary RPE cell growth, optimizing the matrix production procedure may in the future yield nanostructured collagen matrices serving as transferable cell sheet carriers.
Water Dissociation on CeO2(100) and CeO2(111) Thin Films
Energy Technology Data Exchange (ETDEWEB)
Mullins, David R [ORNL; Albrecht, Peter M [ORNL; Chen, Tsung-Liang [ORNL; Calaza, Florencia C [ORNL; Biegalski, Micahel [Oak Ridge National Laboratory (ORNL); Christen, Hans [Oak Ridge National Laboratory (ORNL); Overbury, Steven {Steve} H [ORNL
2012-01-01
This study reports and compares the adsorption and dissociation of water on oxidized and reduced CeO{sub 2}(100) and CeO{sub 2}(111) thin films. Water adsorbs dissociatively on both surfaces. On fully oxidized CeO{sub 2}(100) the resulting surface hydroxyls are relatively stable and recombine and desorb as water over a range from 200 to 600 K. The hydroxyls are much less stable on oxidized CeO{sub 2}(111), recombining and desorbing between 200 and 300 K. Water produces 30% more hydroxyls on reduced CeO{sub 1.7}(100) than on oxidized CeO{sub 2}(100). The hydroxyl concentration increases by 160% on reduced CeO{sub 1.7}(111) compared to oxidized CeO{sub 2}(111). On reduced CeO{sub 1.7}(100) most of the hydroxyls still recombine and desorb as water between 200 and 750 K. Most of the hydroxyls on reduced CeO{sub 1.7}(111) react to produce H{sub 2} at 560 K, leaving O on the surface. A relatively small amount of H{sub 2} is produced from reduced CeO{sub 1.7}(100) between 450 and 730 K. The differences in the adsorption and reaction of water on CeO{sub X}(100) and CeO{sub X}(111) are attributed to different adsorption sites on the two surfaces. The adsorption site on CeO{sub 2}(100) is a bridging site between two Ce cations. This adsorption site does not change when the ceria is reduced. The adsorption site on CeO{sub 2}(111) is atop a single Ce cation, and the proton is transferred to a surface O in a site between three Ce cations. When the CeO{sub X}(111) is reduced, vacancy sites are produced which allows the water to adsorb and dissociate on the 3-fold Ce cation sites.
An Algebraic Relation between Consimilarity and Similarity of Quaternion Matrices and Applications
Directory of Open Access Journals (Sweden)
Tongsong Jiang
2014-01-01
Full Text Available This paper, by means of complex representation of a quaternion matrix, discusses the consimilarity of quaternion matrices, and obtains a relation between consimilarity and similarity of quaternion matrices. It sets up an algebraic bridge between consimilarity and similarity, and turns the theory of consimilarity of quaternion matrices into that of ordinary similarity of complex matrices. This paper also gives algebraic methods for finding coneigenvalues and coneigenvectors of quaternion matrices by means of complex representation of a quaternion matrix.
A comparison between Ce(III) and Ce(IV) ions in photocatalytic degradation of organic pollutants
Institute of Scientific and Technical Information of China (English)
程强; 施薇; 段炼; 孙彬哲; 李晓霞; 徐爱华
2015-01-01
Nano cerium oxides are efficient photocatalysts for pollutants degradation with highly dispersed Ce(III) ions as the sug-gested active species to promote the reaction, while Ce(IV) species do not behave as a catalyst. In this paper, to understand the mechanism of Ce-based photocatalysts, we studied the comparison of simple cerium ions, Ce(III) and Ce(IV) in aqueous solution for organic pollutants degradation under UV irradiation. Orange II (AOII), methyl orange, andp-nitrophenol were selected as the target pollutants. The formation and contribution of reactive oxygen species, the kinetics of Ce(IV) photoreduction and Ce(III) photooxida-tion, and the influence of solution pH were investigated in detail. It was found that at low pH Ce(IV) ions showed a higher activity for hydroxyl radicals production and AOII degradation than Ce(III) ions, which could be attributed to its fast reduction rate to Ce(III). However, its activity dramatically decreased when solution pH increased, and was also strongly influenced by the type of pollutants; while Ce(III) exhibited high degradation efficiency of all the tested pollutants over a wide pH range.
Randomized Algorithms for Matrices and Data
Mahoney, Michael W.
2012-03-01
This chapter reviews recent work on randomized matrix algorithms. By “randomized matrix algorithms,” we refer to a class of recently developed random sampling and random projection algorithms for ubiquitous linear algebra problems such as least-squares (LS) regression and low-rank matrix approximation. These developments have been driven by applications in large-scale data analysis—applications which place very different demands on matrices than traditional scientific computing applications. Thus, in this review, we will focus on highlighting the simplicity and generality of several core ideas that underlie the usefulness of these randomized algorithms in scientific applications such as genetics (where these algorithms have already been applied) and astronomy (where, hopefully, in part due to this review they will soon be applied). The work we will review here had its origins within theoretical computer science (TCS). An important feature in the use of randomized algorithms in TCS more generally is that one must identify and then algorithmically deal with relevant “nonuniformity structure” in the data. For the randomized matrix algorithms to be reviewed here and that have proven useful recently in numerical linear algebra (NLA) and large-scale data analysis applications, the relevant nonuniformity structure is defined by the so-called statistical leverage scores. Defined more precisely below, these leverage scores are basically the diagonal elements of the projection matrix onto the dominant part of the spectrum of the input matrix. As such, they have a long history in statistical data analysis, where they have been used for outlier detection in regression diagnostics. More generally, these scores often have a very natural interpretation in terms of the data and processes generating the data. For example, they can be interpreted in terms of the leverage or influence that a given data point has on, say, the best low-rank matrix approximation; and this
Macromolecular crowding for tailoring tissue-derived fibrillated matrices.
Magno, Valentina; Friedrichs, Jens; Weber, Heather M; Prewitz, Marina C; Tsurkan, Mikhail V; Werner, Carsten
2017-06-01
Tissue-derived fibrillated matrices can be instrumental for the in vitro reconstitution of multiphasic extracellular microenvironments. However, despite of several advantages, the obtained scaffolds so far offer a rather narrow range of materials characteristics only. In this work, we demonstrate how macromolecular crowding (MMC) - the supplementation of matrix reconstitution media with synthetic or natural macromolecules in ways to create excluded volume effects (EVE) - can be employed for tailoring important structural and biophysical characteristics of kidney-derived fibrillated matrices. Porcine kidneys were decellularized, ground and the obtained extracellular matrix (ECM) preparations were reconstituted under varied MMC conditions. We show that MMC strongly influences the fibrillogenesis kinetics and impacts the architecture and the elastic modulus of the reconstituted matrices, with diameters and relative alignment of fibrils increasing at elevated concentrations of the crowding agent Ficoll400, a nonionic synthetic polymer of sucrose. Furthermore, we demonstrate how MMC modulates the distribution of key ECM molecules within the reconstituted matrix scaffolds. As a proof of concept, we compared different variants of kidney-derived fibrillated matrices in cell culture experiments referring to specific requirements of kidney tissue engineering approaches. The results revealed that MMC-tailored matrices support the morphogenesis of human umbilical vein endothelial cells (HUVECs) into capillary networks and of murine kidney stem cells (KSCs) into highly branched aggregates. The established methodology is concluded to provide generally applicable new options for tailoring tissue-specific multiphasic matrices in vitro. Tissue-derived fibrillated matrices can be instrumental for the in vitro reconstitution of multiphasic extracellular microenvironments. However, despite of several advantages, the obtained scaffolds so far offer a rather narrow range of materials
Review of analytical methods for the quantification of iodine in complex matrices
Energy Technology Data Exchange (ETDEWEB)
Shelor, C. Phillip [Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, TX 76019-0065 (United States); Dasgupta, Purnendu K., E-mail: Dasgupta@uta.edu [Department of Chemistry and Biochemistry, University of Texas at Arlington, Arlington, TX 76019-0065 (United States)
2011-09-19
Highlights: {yields} We focus on iodine in biological samples, notably urine and milk. {yields} Sample preparation and the Sandell-Kolthoff method are extensively discussed. - Abstract: Iodine is an essential element of human nutrition. Nearly a third of the global population has insufficient iodine intake and is at risk of developing Iodine Deficiency Disorders (IDD). Most countries have iodine supplementation and monitoring programs. Urinary iodide (UI) is the biomarker used for epidemiological studies; only a few methods are currently used routinely for analysis. These methods either require expensive instrumentation with qualified personnel (inductively coupled plasma-mass spectrometry, instrumental nuclear activation analysis) or oxidative sample digestion to remove potential interferences prior to analysis by a kinetic colorimetric method originally introduced by Sandell and Kolthoff {approx}75 years ago. The Sandell-Kolthoff (S-K) method is based on the catalytic effect of iodide on the reaction between Ce{sup 4+} and As{sup 3+}. No available technique fully fits the needs of developing countries; research into inexpensive reliable methods and instrumentation are needed. There have been multiple reviews of methods used for epidemiological studies and specific techniques. However, a general review of iodine determination on a wide-ranging set of complex matrices is not available. While this review is not comprehensive, we cover the principal developments since the original development of the S-K method.
Hierarchical Matrices Method and Its Application in Electromagnetic Integral Equations
Directory of Open Access Journals (Sweden)
Han Guo
2012-01-01
Full Text Available Hierarchical (H- matrices method is a general mathematical framework providing a highly compact representation and efficient numerical arithmetic. When applied in integral-equation- (IE- based computational electromagnetics, H-matrices can be regarded as a fast algorithm; therefore, both the CPU time and memory requirement are reduced significantly. Its kernel independent feature also makes it suitable for any kind of integral equation. To solve H-matrices system, Krylov iteration methods can be employed with appropriate preconditioners, and direct solvers based on the hierarchical structure of H-matrices are also available along with high efficiency and accuracy, which is a unique advantage compared to other fast algorithms. In this paper, a novel sparse approximate inverse (SAI preconditioner in multilevel fashion is proposed to accelerate the convergence rate of Krylov iterations for solving H-matrices system in electromagnetic applications, and a group of parallel fast direct solvers are developed for dealing with multiple right-hand-side cases. Finally, numerical experiments are given to demonstrate the advantages of the proposed multilevel preconditioner compared to conventional “single level” preconditioners and the practicability of the fast direct solvers for arbitrary complex structures.
Osteocalcin/fibronectin-functionalized collagen matrices for bone tissue engineering.
Kim, S G; Lee, D S; Lee, S; Jang, J-H
2015-06-01
Collagen is the most abundant protein found in the extracellular matrix and is widely used to build scaffolds for biomedical applications which are the result of its biocompatibility and biodegradability. In the present study, we constructed a rhOCN/FNIII9-10 fusion protein and rhOCN/FNIII9-10-functionalized collagen matrices and investigated the potential value for bone tissue engineering. In vitro studies carried out with preosteoblastic MC3T3-E1 cells showed that rhOCN/FNIII9-10 fusion protein promoted cell adhesion and the mRNA levels of osteogenic markers including osteocalcin, runt-related transcription factor 2, alkaline phosphatase (ALP), and collagen type I. In addition, rhOCN/FNIII9-10-functionalized collagen matrices showed significant induction of the ALP activity more than rhFNIII9-10-functionalized collagen matrices or collagen matrices alone. These results suggested that rhOCN/FNIII9-10-functionalized collagen matrices have potential for bone tissue engineering.
Learning Discriminative Stein Kernel for SPD Matrices and Its Applications.
Zhang, Jianjia; Wang, Lei; Zhou, Luping; Li, Wanqing
2016-05-01
Stein kernel (SK) has recently shown promising performance on classifying images represented by symmetric positive definite (SPD) matrices. It evaluates the similarity between two SPD matrices through their eigenvalues. In this paper, we argue that directly using the original eigenvalues may be problematic because: 1) eigenvalue estimation becomes biased when the number of samples is inadequate, which may lead to unreliable kernel evaluation, and 2) more importantly, eigenvalues reflect only the property of an individual SPD matrix. They are not necessarily optimal for computing SK when the goal is to discriminate different classes of SPD matrices. To address the two issues, we propose a discriminative SK (DSK), in which an extra parameter vector is defined to adjust the eigenvalues of input SPD matrices. The optimal parameter values are sought by optimizing a proxy of classification performance. To show the generality of the proposed method, three kernel learning criteria that are commonly used in the literature are employed as a proxy. A comprehensive experimental study is conducted on a variety of image classification tasks to compare the proposed DSK with the original SK and other methods for evaluating the similarity between SPD matrices. The results demonstrate that the DSK can attain greater discrimination and better align with classification tasks by altering the eigenvalues. This makes it produce higher classification performance than the original SK and other commonly used methods.
The MATRICS Consensus Cognitive Battery (MCCB): performance and functional correlates.
Lystad, June Ullevoldsæter; Falkum, Erik; Mohn, Christine; Haaland, Vegard Øksendal; Bull, Helen; Evensen, Stig; Rund, Bjørn Rishovd; Ueland, Torill
2014-12-30
Neurocognitive impairment is a core feature in psychotic disorders and the MATRICS Consensus Cognitive Battery (MCCB) is now widely used to assess neurocognition in this group. The MATRICS has been translated into several languages, including Norwegian; although this version has yet to be investigated in an adult clinical population. Further, the relationship between the MATRICS and different measures of functioning needs examination. The purpose of this study was to describe neurocognition assessed with the Norwegian version of the MATRICS battery in a sample of patients with psychotic disorders compared to age and gender matched healthy controls and to examine the association with educational-, occupational- and social-functioning in the patient group. One hundred and thirty one patients and 137 healthy controls completed the battery. The Norwegian version of the MATRICS was sensitive to the magnitude of neurocognitive impairments in patients with psychotic disorders, with patients displaying significant impairments on all domains relative to healthy controls. Neurocognition was also related to both self-rated and objective functional measures such as social functioning, educational- and employment-history.
Laplacian matrices of weighted digraphs represented as quantum states
Adhikari, Bibhas; Banerjee, Subhashish; Adhikari, Satyabrata; Kumar, Atul
2017-03-01
Representing graphs as quantum states is becoming an increasingly important approach to study entanglement of mixed states, alternate to the standard linear algebraic density matrix-based approach of study. In this paper, we propose a general weighted directed graph framework for investigating properties of a large class of quantum states which are defined by three types of Laplacian matrices associated with such graphs. We generalize the standard framework of defining density matrices from simple connected graphs to density matrices using both combinatorial and signless Laplacian matrices associated with weighted directed graphs with complex edge weights and with/without self-loops. We also introduce a new notion of Laplacian matrix, which we call signed Laplacian matrix associated with such graphs. We produce necessary and/or sufficient conditions for such graphs to correspond to pure and mixed quantum states. Using these criteria, we finally determine the graphs whose corresponding density matrices represent entangled pure states which are well known and important for quantum computation applications. We observe that all these entangled pure states share a common combinatorial structure.
Hypersymmetric functions and Pochhammers of 2×2 nonautonomous matrices
Directory of Open Access Journals (Sweden)
A. F. Antippa
2004-01-01
Full Text Available We introduce the hypersymmetric functions of 2×2 nonautonomous matrices and show that they are related, by simple expressions, to the Pochhammers (factorial polynomials of these matrices. The hypersymmetric functions are generalizations of the associated elementary symmetric functions, and for a specific class of 2×2 matrices, having a high degree of symmetry, they reduce to these latter functions. This class of matrices includes rotations, Lorentz boosts, and discrete time generators for the harmonic oscillators. The hypersymmetric functions are defined over four sets of independent indeterminates using a triplet of interrelated binary partitions. We work out the algebra of this triplet of partitions and then make use of the results in order to simplify the expressions for the hypersymmetric functions for a special class of matrices. In addition to their obvious applications in matrix theory, in coupled difference equations, and in the theory of symmetric functions, the results obtained here also have useful applications in problems involving successive rotations, successive Lorentz transformations, discrete harmonic oscillators, and linear two-state systems.
Dirac Matrices and Feynman's Rest of the Universe
Kim, Young S
2012-01-01
There are two sets of four-by-four matrices introduced by Dirac. The first set consists of fifteen Majorana matrices derivable from his four $\\gamma$ matrices. These fifteen matrices can also serve as the generators of the group $SL(4,r)$. The second set consists of ten generators of the $Sp(4)$ group which he derived from two coupled harmonic oscillators. In classical mechanics, it is possible to extend the symmetry of the coupled oscillators to the SL(4,r) regime with fifteen Majorana matrices, while quantum mechanics allows only ten generators. This difference can serve as an illustrative example of Feynman's rest of the universe. The universe of the coupled oscillators consists of fifteen generators, and the ten generators are for the world where quantum mechanics is valid. The remaining five generators belong to the rest of the universe. It is noted that the groups $SL(4,r)$ and $Sp(4)$ are locally isomorphic to the Lorentz groups O(3,3) and O(3,2) respectively. This allows us to interpret Feynman's rest...
Electronic structure of LaTe and CeTe
Energy Technology Data Exchange (ETDEWEB)
Chainani, A., E-mail: chainania@gmail.com [RIKEN SPring-8 Centre, 1-1-1 Kouto, Hyogo 679-5148 (Japan); Department of Physics, Tohoku University, Aramaki, Aoba-ku, Sendai 980-8578 (Japan); Oura, M. [RIKEN SPring-8 Centre, 1-1-1 Kouto, Hyogo 679-5148 (Japan); Matsunami, M. [UVSOR Facility, Institute for Molecular Science, Okazaki 444-8585 (Japan); Ochiai, A.; Takahashi, T. [Department of Physics, Tohoku University, Aramaki, Aoba-ku, Sendai 980-8578 (Japan); Tanaka, Y. [RIKEN SPring-8 Centre, 1-1-1 Kouto, Hyogo 679-5148 (Japan); Graduate School of Material Science, University of Hyogo, 3-2-1 Kouto, Hyogo 678-1297 (Japan); Tamasaku, K.; Kohmura, Y.; Ishikawa, T. [RIKEN SPring-8 Centre, 1-1-1 Kouto, Hyogo 679-5148 (Japan)
2016-04-15
Highlights: • Hard X-ray and soft X-ray photoelectron spectroscopy of LaTe and CeTe. • Evidence for Kondo screening in antiferromagnetic(T{sub N} = 2.2 K) compound CeTe. • Suppressed Kondo resonance in CeTe compared to typical Kondo materials. - Abstract: We report a comparative study of the electronic structure of the compounds LaTe and CeTe, both of which crystallize in the rock salt structure. LaTe is a paramagnetic metal while CeTe is known to exhibit anomalous Kondo-like transport behaviour and undergoes a transition to a complex magnetically ordered state at low temperature (T{sub N} = 2.2 K). We carry out hard X-ray photoelectron spectroscopy (HAXPES) of the core-levels and valence band of LaTe and CeTe at T = 20 K, in order to characterize their intrinsic electronic structure, and to address the role of Kondo effect on the electronic structure of CeTe. The bulk sensitive core level HAXPES spectra show evidence of screened features in the La 3d and Ce 3d states mixed with plasmon features. From a careful analysis of the Te, La and Ce derived core levels, we separate out the respective origins of the satellites and show that CeTe indeed exhibits definitive but weak f{sup 0} and f{sup 2} satellites due to Kondo screening, in addition to the main f{sup 1} peak. The comparison of the valence band spectra of CeTe obtained using HAXPES and soft X-ray PES clearly identifies the Ce 4f derived features. Resonant photoelectron spectrosocopy across the Ce 3d − 4f threshold confirms the Ce 4f{sup 1} final state at the Fermi level, corresponding to the tail of the Kondo resonance feature which occurs above the Fermi level, while the Ce 4f{sup 0} final state feature is observed at a binding energy of 2.4 eV. The 4f{sup 0} and 4f{sup 1} final states show giant resonances compared to the off-resonant spectra. However, in contrast to typical Kondo systems, the tail of the Ce 4f{sup 1} Kondo resonance at the Fermi level is relatively suppressed compared to the Ce 4f
Maráková, Katarína; Piešt'anský, Juraj; Veizerová, Lucia; Galba, Jaroslav; Dokupilová, Svetlana; Havránek, Emil; Mikuš, Peter
2013-06-01
The present work illustrates potentialities of CE hyphenated with MS/MS for the simultaneous determination and identification of a mixture of simultaneously acting drugs in pharmaceutical and biological matrices. Here, the hyphenation was provided by ESI interface, while the MS/MS technique was based on the triple quadrupole configuration. Three drugs, namely pheniramine, phenylephrine, and paracetamol were determined and identified with high reliability due to their characterization in three different dimensions, i.e. electrophoresis and MS/MS, that prevented practically any interference. Appropriately selected transitions of the analytes (parent ion-quantifier product ion-qualifier product ion) provided their selective determination at maximum S/N. The proposed CE-MS/MS method was validated (LOD/LOQ, linearity, precision, recovery, accuracy) and applied for (i) the multidrug composition pharmaceuticals, namely Theraflu®, and (ii) human urine taken after per-oral administration of the same pharmaceutical preparation. The method was applied also for the investigation of potential weak associates of the drugs and monitoring of predicted (bio)degradation products of the drugs. Successful validation and application of the proposed method suggest its routine use in highly effective and reliable advanced drug control and biomedical research.
Study of Ce-modified antibacterial 316L stainless steel
Directory of Open Access Journals (Sweden)
Yuan Junping
2012-11-01
Full Text Available 316L stainless steel is widely used for fashion jewelry, but it can carry a large number of bacteria and bring the risk of infection since the steel has no antimicrobial performance. In this paper, the effects of Ce on the antibacterial property, corrosion resistance and processability of 316L were studied by microscopic observation, thin-film adhering quantitative bacteriostasis, and electrochemical and mechanical tests. The results show that a trace of Ce can distribute uniformly in the matrix of 316L and slightly improve its corrosion resistance in artificial sweat. With an increase in Ce content, the Ce is prone to form clustering, which degrades the corrosion resistance and the processability. The Ce-containing 316L exhibits Hormesis effect against S. aureus. A small Ce addition stimulates the growth of S. aureus. As the Ce content increases, the modified 316L exhibits an improved antibacterial efficacy. The more Ce is added, the better antibacterial capability is achieved. Overall, if the 316L is modified with Ce alone, it is difficult to obtain the optimal combination of corrosion resistance, antibacterial performance and processability. In spite of that, 0.15 wt.%-0.20 wt.% Ce around is inferred to be the best trade-off.
Comment on "138La-138Ce-136Ce nuclear cosmochronometer of the supernova neutrino process"
Von Neumann-Cosel, P; Byelikov, A
2009-01-01
The nuclear chosmochronometer suggested by Hayakawa et al. [Phys. Rev.C 77, 065802 (2008)] based on the 138La-138Ce-136Ce abundance ratio in presolar grains would be affected by the existence of a hitherto unknown low-energy 1+ state in 138La. Results of a recent high-resolution study of the 138Ba(3He,t) reaction under kinematics selectively populating 1+ states in 138La through Gamow-Teller transitions provides strong evidence against the existence of such a hypothetical state.
Search for double beta decay of $^{136}$Ce and $^{138}$Ce with HPGe gamma detector
Belli, P; Boiko, R S; Cappella, F; Cerulli, R; Danevich, F A; Incicchitti, A; Kropivyansky, B N; Laubenstein, M; Poda, D V; Polischuk, O G; Tretyak, V I
2014-01-01
Search for double $\\beta$ decay of $^{136}$Ce and $^{138}$Ce was realized with 732 g of deeply purified cerium oxide sample measured over 1900 h with the help of an ultra-low background HPGe $\\gamma$ detector with a volume of 465 cm$^3$ at the STELLA facility of the Gran Sasso National Laboratories of the INFN (Italy). New improved half-life limits on double beta processes in the cerium isotopes were set at the level of $\\lim T_{1/2}\\sim 10^{17}-10^{18}$~yr; many of them are even two orders of magnitude larger than the best previous results.
Oxidation of Ce(III) in Foam Decontaminant by Ozone
Energy Technology Data Exchange (ETDEWEB)
Jung, Chong Hun; Yoon, I. H.; Choi, W. K.; Moon, J. K.; Yang, H. B. [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Lee, J. S. [Gachon University, Seongnam (Korea, Republic of)
2016-10-15
A nanoparticle-based foam decontaminant is composed of a surfactant and nanoparticles for the generation and maintenance of foam, and a chemical decontamination agent made of Ce(IV) dissolved in nitric acid. Ce(IV) will be reduced to Ce(III) through the decontamination process. Oxidizing cerium(III) can be reused as a decontamination agent, Ce(IV). Oxidation treatment technology by ozone uses its strong oxidizing power. It can be regarded as an environmentally friendly process, because ozone cannot be stored and transported like other industrial gases (because it quickly decays into diatomic oxygen) and must therefore be produced on site, and used ozone can decompose immediately. The ozonation treatment of Ce(III) in foam decontaminant containing a surfactant is necessary for the effective regeneration of Ce(III). Thus, the present study was undertaken to determine the optimal conditions for ozonation treatment in the regeneration of Ce(III) into Ce(IV) in the nanoparticle-based foam decontaminant containing surfactant. This study was undertaken to determine the optimal conditions for ozonation treatment in the regeneration of Ce(III) to Ce(IV) in nanoparticle-based foam decontaminant containing a TBS surfactant. The oxidation conversion rate of Ce(III) was increased with an increase in the flow rate of the gas mixture and ozone injection amount. The oxidation time required for the 100% oxidation conversion of Ce(III) to Ce(IV) at a specific ozone injection amount can be predicted from these experimental data.
k-控制阵%k-dominating Fuzzy Matrices
Institute of Scientific and Technical Information of China (English)
孙华春
2006-01-01
The definition of k-dominating fuzzy matrices has been introduced. The relation between k-dominating fuzzy matrices and circularly k-dominating fuzzy matrices is discussed. We point out that the convergence or oscillating index of the power sequence of an n × n k-dominating matrix is bounded by (n-1)k+m from above; and if it is oscillating, then the period index is a factor of k.%给出k-控制阵的定义,讨论k-控制阵与k-圈控制阵的关系,指出k-控制阵的周期是k的一个因子,指数不大于(n-1)k+m.
Square matrices of order 2 theory, applications, and problems
Pop, Vasile
2017-01-01
This unique and innovative book presents an exciting and complete detail of all the important topics related to the theory of square matrices of order 2. The readers exploring every detailed aspect of matrix theory are gently led toward understanding advanced topics. They will follow every notion of matrix theory with ease, accumulating a thorough understanding of algebraic and geometric aspects of matrices of order 2. The prime jewel of this book is its offering of an unusual collection of problems, theoretically motivated, most of which are new, original, and seeing the light of publication for the first time in the literature. Nearly all of the exercises are presented with detailed solutions and vary in difficulty from easy to more advanced. Many problems are particularly challenging. These, and not only these, invite the reader to unleash their creativity and research capabilities and to discover their own methods of attacking a problem. Matrices have a vast practical importance to mathematics, science, a...
Microscale extraction method for HPLC carotenoid analysis in vegetable matrices
Directory of Open Access Journals (Sweden)
Sidney Pacheco
2014-10-01
Full Text Available In order to generate simple, efficient analytical methods that are also fast, clean, and economical, and are capable of producing reliable results for a large number of samples, a micro scale extraction method for analysis of carotenoids in vegetable matrices was developed. The efficiency of this adapted method was checked by comparing the results obtained from vegetable matrices, based on extraction equivalence, time required and reagents. Six matrices were used: tomato (Solanum lycopersicum L., carrot (Daucus carota L., sweet potato with orange pulp (Ipomoea batatas (L. Lam., pumpkin (Cucurbita moschata Duch., watermelon (Citrullus lanatus (Thunb. Matsum. & Nakai and sweet potato (Ipomoea batatas (L. Lam. flour. Quantification of the total carotenoids was made by spectrophotometry. Quantification and determination of carotenoid profiles were formulated by High Performance Liquid Chromatography with photodiode array detection. Microscale extraction was faster, cheaper and cleaner than the commonly used one, and advantageous for analytical laboratories.
Scattering matrices in non-uniformly lined ducts
Demir, Ahmet
2017-02-01
Sudden area expansion and sudden area contraction in an infinitely long duct with discontinuous locally reacting lining are defined by respective mixed boundary value problems. In the absence of a sudden area change, a separate problem with an infinite duct having bifid lining on its wall is described. Introducing Fourier transform along the duct axis boundary value problems is solved by the well-known Wiener-Hopf technique, and then, corresponding scattering matrices are constructed. To show the proper use of scattering matrices in the case of several discontinuities and also validation and comparison purposes, transmitted field in a duct with an inserted expansion chamber whose walls are treated by acoustically absorbent material is derived by the help of the relevant scattering matrices. A perfect agreement is observed when the transmitted fields are compared numerically with a similar work exists in the literature.
Opening the Rome-Southampton window for operator mixing matrices
Arthur, R; Garron, N; Kelly, C; Lytle, A T
2011-01-01
We show that the running of operators which mix under renormalization can be computed fully non-perturbatively as a product of continuum step scaling matrices. These step scaling matrices are obtained by taking the "ratio" of Z matrices computed at different energies in an RI-MOM type scheme for which twisted boundary conditions are an essential ingredient. Our method allows us to relax the bounds of the Rome-Southampton window. We also explain why such a method is important in view of the light quark physics program of the RBC-UKQCD collaborations. To illustrate our method, using n_f=2+1 domain-wall fermions, we compute the non-perturbative running matrix of four-quark operators needed in K->pipi decay and neutral kaon mixing. Our results are then compared to perturbation theory.
Convex Optimization methods for computing the Lyapunov Exponent of matrices
Protasov, Vladimir Yu
2012-01-01
We introduce a new approach to evaluate the largest Lyapunov exponent of a family of nonnegative matrices. The method is based on using special positive homogeneous functionals on $R^{d}_+,$ which gives iterative lower and upper bounds for the Lyapunov exponent. They improve previously known bounds and converge to the real value. The rate of convergence is estimated and the efficiency of the algorithm is demonstrated on several problems from applications (in functional analysis, combinatorics, and lan- guage theory) and on numerical examples with randomly generated matrices. The method computes the Lyapunov exponent with a prescribed accuracy in relatively high dimensions (up to 60). We generalize this approach to all matrices, not necessar- ily nonnegative, derive a new universal upper bound for the Lyapunov exponent, and show that such a lower bound, in general, does not exist.
Asymmetric correlation matrices: an analysis of financial data
Livan, G.; Rebecchi, L.
2012-06-01
We analyse the spectral properties of correlation matrices between distinct statistical systems. Such matrices are intrinsically non-symmetric, and lend themselves to extend the spectral analyses usually performed on standard Pearson correlation matrices to the realm of complex eigenvalues. We employ some recent random matrix theory results on the average eigenvalue density of this type of matrix to distinguish between noise and non-trivial correlation structures, and we focus on financial data as a case study. Namely, we employ daily prices of stocks belonging to the American and British stock exchanges, and look for the emergence of correlations between two such markets in the eigenvalue spectrum of their non-symmetric correlation matrix. We find several non trivial results when considering time-lagged correlations over short lags, and we corroborate our findings by additionally studying the asymmetric correlation matrix of the principal components of our datasets.
Inverse of invertible standard multi-companion matrices with applications
Directory of Open Access Journals (Sweden)
Hazem I. El Shekh Ahmed
2015-01-01
Full Text Available The inverse of invertible standard multi-companion matrices will be derived and introduced as a new technique for generation of periodic autoregression models to get the desired spectrum and extract the parameters of the model from it when the information of the standard multi-companion matrices is not enough for the extracting of the parameters of the model. We will find explicit expressions for the generalized eigenvectors of the inverse of invertible standard multi-companion matrices such that each generalized eigenvector depends on the corresponding eigenvalue therefore we obtain a parameterization of the inverse of invertible standard multi-companion matrix through the eigenvalues and these additional quantities. The results can be applied to statistical estimation, simulation and theoretical studies of periodically correlated and multivariate time series in both discrete and continuous-time series.
Composition of quantum operations and products of random matrices
Roga, Wojciech; Zyczkowski, Karol
2011-01-01
Spectral properties of evolution operators corresponding to random maps and quantized chaotic systems strongly interacting with an environment can be described by the ensemble of non-hermitian random matrices from the real Ginibre ensemble. We analyze evolution operators Psi=Psi_s...Psi_1 representing the composition of s random maps and demonstrate that their complex eigenvalues are asymptotically described by the law of Burda et al. obtained for a product of s independent random complex Ginibre matrices. Numerical data support the conjecture that the same results are applicable to characterize the distribution of eigenvalues of the s-th power of a random Ginibre matrix. Squared singular values of Psi are shown to be described by the Fuss-Catalan distribution of order s. Results obtained for products of random Ginibre matrices are also capable to describe the s-step evolution operator for a model deterministic dynamical system - a generalized quantum baker map subjected to strong interaction with an environm...
Induced Ginibre ensemble of random matrices and quantum operations
Fischmann, J; Khoruzhenko, B A; Sommers, H -J; Zyczkowski, K
2011-01-01
A generalisation of the Ginibre ensemble of non-Hermitian random square matrices is introduced. The corresponding probability measure is induced by the ensemble of rectangular Gaussian matrices via a quadratisation procedure. We derive the joint probability density of eigenvalues for such induced Ginibre ensemble and study various spectral correlation functions for complex and real matrices, and analyse universal behaviour in the limit of large dimensions. In this limit the eigenvalues of the induced Ginibre ensemble cover uniformly a ring in the complex plane. The real induced Ginibre ensemble is shown to be useful to describe statistical properties of evolution operators associated with random quantum operations, for which the dimensions of the input state and the output state do differ.
Formation of complex anodic films on porous alumina matrices
Indian Academy of Sciences (India)
Alexander Zahariev; Assen Girginov
2003-04-01
The kinetics of growth of complex anodic alumina films was investigated. These films were formed by filling porous oxide films (matrices) having deep pores. The porous films (matrices) were obtained voltastatically in (COOH)2 aqueous solution under various voltages. The filling was done by re-anodization in an electrolyte solution not dissolving the film. Data about the kinetics of re-anodization depending on the porosity of the matrices were obtained. On the other hand, the slopes of the kinetic curves during reanodization were calculated by two equations expressing the dependence of these slopes on the ionic current density. A discrepancy was ascertained between the values of the calculated slopes and those experimentally found. For this discrepancy a possible explanation is proposed, related to the temperature increase in the film, because of that the real current density significantly increases during re-anodization.
Nano-Fiber Reinforced Enhancements in Composite Polymer Matrices
Chamis, Christos C.
2009-01-01
Nano-fibers are used to reinforce polymer matrices to enhance the matrix dependent properties that are subsequently used in conventional structural composites. A quasi isotropic configuration is used in arranging like nano-fibers through the thickness to ascertain equiaxial enhanced matrix behavior. The nano-fiber volume ratios are used to obtain the enhanced matrix strength properties for 0.01,0.03, and 0.05 nano-fiber volume rates. These enhanced nano-fiber matrices are used with conventional fiber volume ratios of 0.3 and 0.5 to obtain the composite properties. Results show that nano-fiber enhanced matrices of higher than 0.3 nano-fiber volume ratio are degrading the composite properties.
A Workshop on Algebraic Design Theory and Hadamard Matrices
2015-01-01
This volume develops the depth and breadth of the mathematics underlying the construction and analysis of Hadamard matrices and their use in the construction of combinatorial designs. At the same time, it pursues current research in their numerous applications in security and cryptography, quantum information, and communications. Bridges among diverse mathematical threads and extensive applications make this an invaluable source for understanding both the current state of the art and future directions. The existence of Hadamard matrices remains one of the most challenging open questions in combinatorics. Substantial progress on their existence has resulted from advances in algebraic design theory using deep connections with linear algebra, abstract algebra, finite geometry, number theory, and combinatorics. Hadamard matrices arise in a very diverse set of applications. Starting with applications in experimental design theory and the theory of error-correcting codes, they have found unexpected and important ap...
The road to deterministic matrices with the restricted isometry property
Bandeira, Afonso S; Mixon, Dustin G; Wong, Percy
2012-01-01
The restricted isometry property (RIP) is a well-known matrix condition that provides state-of-the-art reconstruction guarantees for compressed sensing. While random matrices are known to satisfy this property with high probability, deterministic constructions have found less success. In this paper, we consider various techniques for demonstrating RIP deterministically, some popular and some novel, and we evaluate their performance. In evaluating some techniques, we apply random matrix theory and inadvertently find a simple alternative proof that certain random matrices are RIP. Later, we propose a particular class of matrices as candidates for being RIP, namely, equiangular tight frames (ETFs). Using the known correspondence between real ETFs and strongly regular graphs, we investigate certain combinatorial implications of a real ETF being RIP. Specifically, we give probabilistic intuition for a new bound on the clique number of Paley graphs of prime order, and we conjecture that the corresponding ETFs are R...
Asymmetric matrices in an analysis of financial correlations
Kwapien, J; Górski, A Z; Oswiecimka, P
2006-01-01
Financial markets are highly correlated systems that reveal both the inter-market dependencies and the correlations among their different components. Standard analyzing techniques include correlation coefficients for pairs of signals and correlation matrices for rich multivariate data. In the latter case one constructs a real symmetric matrix with real non-negative eigenvalues describing the correlation structure of the data. However, if one performs a correlation-function-like analysis of multivariate data, when a stress is put on investigation of delayed dependencies among different types of signals, one can calculate an asymmetric correlation matrix with complex eigenspectrum. From the Random Matrix Theory point of view this kind of matrices is closely related to Ginibre Orthogonal Ensemble (GinOE). We present an example of practical application of such matrices in correlation analyses of empirical data. By introducing the time lag, we are able to identify temporal structure of the inter-market correlation...
Limiting Spectral Distribution of Block Matrices with Toeplitz Block Structure
Basu, Riddhipratim; Ganguly, Shirshendu; Hazra, Rajat Subhra
2011-01-01
We study two specific symmetric random block Toeplitz (of dimension $k \\times k$) matrices: where the blocks (of size $n \\times n$) are (i) matrices with i.i.d. entries, and (ii) asymmetric Toeplitz matrices. Under suitable assumptions on the entries, their limiting spectral distributions (LSDs) exist (after scaling by $\\sqrt{nk}$) when (a) $k$ is fixed and $n \\to\\infty$ (b) $n$ is fixed and $k\\rightarrow \\infty$ (c) $n$ and $k$ go to $\\infty$ simultaneously. Further the LSD's obtained in (a) and (b) coincide with those in (c) when $n$ or respectively $k$ tends to infinity. This limit in (c) is the semicircle law in case (i). In Case (ii) the limit is related to the limit of the random symmetric Toepiltz matrix as obtained by Bryc et al.(2006) and Hammond and Miller(2005).
On the exponential of matrices in su(4)
Energy Technology Data Exchange (ETDEWEB)
Ramakrishna, Viswanath; Zhou, Hong [Department of Mathematical Sciences and Center for Signals, Systems and Communications, University of Texas at Dallas, PO Box 830688, Richardson, TX 75083 (United States)
2006-03-24
This paper provides explicit techniques to compute the exponentials of a variety of anti-Hermitian matrices in dimension 4. Many of these formulae can be written down directly from the entries of the matrix. Whenever any spectral calculations are required, these can be done in closed form. In many instances only 2 x 2 spectral calculations are required. These formulae cover a wide variety of applications. Conditions on the matrix which render it to admit one of three minimal polynomials are also given. Matrices with these minimal polynomials admit simple and tractable representations for their exponentials. One of these is the Euler-Rodrigues formula. The key technique is the relation between real 4 x 4 matrices and the quaternions.
Non-invasive matrices in human biomonitoring: a review.
Esteban, Marta; Castaño, Argelia
2009-02-01
Humans and other living organisms are exposed to a variety of chemical pollutants that are released into the environment as a consequence of anthropogenic activities. Environmental pollutants are incorporated into the organism by different routes and can then be stored and distributed in different tissues, which leads to an internal concentration that can induce different alterations, adverse effects and/or diseases. Control measures should be taken to avoid these effects and human biomonitoring is a very useful tool that can contribute to this aim. Human biomonitoring uses different matrices to measure the target chemicals depending on the chemical, the amount of matrix necessary for the analysis and the detection limit (LOD) of the analytical technique. Blood is the ideal matrix for most chemicals due to its contact with the whole organism and its equilibrium with organs and tissues where chemicals are stored. However, it has an important disadvantage of being an invasive matrix. The development of new methodology and modern analytical techniques has allowed the use of other matrices that are less or non-invasive, such as saliva, urine, meconium, nails, hair, and semen or breast milk. The presence of a chemical in these matrices reflects an exposure, but correlations between levels in non-invasive matrices and blood must be established to ensure that these levels are related to the total body burden. The development of new biomarkers that are measurable in these matrices will improve non-invasive biomonitoring. This paper reviews studies that measure Cd, Pb, Hg, polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDEs), organochlorine pesticides and phthalates in non-invasive matrices, the most used techniques for measurements and what alternative techniques are available.
Matric variate Pearson type II-Riesz distribution
Directory of Open Access Journals (Sweden)
José A. Díaz-García
2016-10-01
Full Text Available The Pearson type II distribution is well known and is used in the general framework of real normed division algebras and Riesz distribution theory. Also, the so called Pearson type II-Riesz distribution, based on the Kotz–Riesz distribution, is presented in a unified way valid in the context of real, complex, quaternion and octonion random matrices. Specifically, the central nonsingular matric variate generalised Pearson type II-Riesz distribution and beta-Riesz type I distributions are derived in the addressed multiple numerical field settings.
A Class of Transformation Matrices and Its Applications
Directory of Open Access Journals (Sweden)
Wenhui Liu
2014-01-01
Full Text Available This paper studies a class of transformation matrices and its applications. Firstly, we introduce a class of transformation matrices between two different vector operators and give some important properties of it. Secondly, we consider its two applications. The first one is to improve Qian Jiling's formula. And the second one is to deal with the observability of discrete-time stochastic linear systems with Markovian jump and multiplicative noises. A new necessary and sufficient condition for the weak observability will be given in the second application.
Quantum hidden Markov models based on transition operation matrices
Cholewa, Michał; Gawron, Piotr; Głomb, Przemysław; Kurzyk, Dariusz
2017-04-01
In this work, we extend the idea of quantum Markov chains (Gudder in J Math Phys 49(7):072105 [3]) in order to propose quantum hidden Markov models (QHMMs). For that, we use the notions of transition operation matrices and vector states, which are an extension of classical stochastic matrices and probability distributions. Our main result is the Mealy QHMM formulation and proofs of algorithms needed for application of this model: Forward for general case and Vitterbi for a restricted class of QHMMs. We show the relations of the proposed model to other quantum HMM propositions and present an example of application.
Recommendations on the use and design of risk matrices
DEFF Research Database (Denmark)
Duijm, Nijs Jan
2015-01-01
Risk matrices are widely used in risk management. They are a regular feature in various risk management standards and guidelines and are also used as formal corporate risk acceptance criteria. It is only recently, however, that scientific publications have appeared that discuss the weaknesses...... of the risk matrix. The objective of this paper is to explore these weaknesses, and provide recommendations for the use and design of risk matrices. The paper reviews the few relevant publications and adds some observations of its own in order to emphasize existing recommendations and add some suggestions...
UNCONDITIONAL CAUCHY SERIES AND UNIFORM CONVERGENCE ON MATRICES
Institute of Scientific and Technical Information of China (English)
A. AIZPURU; A. GUTIERREZ-DAVILA
2004-01-01
The authors obtain new characterizations of unconditional Cauchy series in terms of separation properties of subfamilies of p(N), and a generalization of the Orlicz-Pettis Theorem is also obtained. New results on the uniform convergence on matrices and a new version of the Hahn-Schur summation theorem are proved. For matrices whose rows define unconditional Cauchy series, a better sufficient condition for the basic Matrix Theorem of Antosik and Swartz, new necessary conditions and a new proof of that theorem are given.
Matrices con entradas enteras e inversa con entradas enteras
Mora, Walter
2004-01-01
Algunos artículos publicados en The American Mathematical Monthly discuten acerca de la construcción de matrices con entradas enteras, valores propios enteros y vectores propios con componentes enteras, en particular en [1] se hace una construcción que además permite construir, de manera sencilla, matrices con entradas enteras cuya inversa también tiene entradas enteras. Este artículo trata de estas últimas construcciones e incluye software en Java para generar y modificar ejemplos y para hac...
Singularity of Sparse Circulant Matrices is NP-complete
Toli, Ilia
2009-01-01
It is shown by Karp reduction that deciding the singularity of $(2^n - 1) \\times (2^n - 1)$ sparse circulant matrices (SC problem) is NP-complete. We can write them only implicitly, by indicating values of the $2 + n(n + 1)/2$ eventually nonzero entries of the first row and can make all matrix operations with them. The positions are $0, 1, 2^{i} + 2^{j}$. The complexity parameter is $n$. Mulmuley's work on the rank of matrices \\cite{Mulmuley87} makes SC stand alone in a list of 3,000 and growing NP-complete problems.
Matrices con entradas enteras e inversa con entradas enteras
Mora, Walter
2004-01-01
Algunos artículos publicados en The American Mathematical Monthly discuten acerca de la construcción de matrices con entradas enteras, valores propios enteros y vectores propios con componentes enteras, en particular en [1] se hace una construcción que además permite construir, de manera sencilla, matrices con entradas enteras cuya inversa también tiene entradas enteras. Este artículo trata de estas últimas construcciones e incluye software en Java para generar y modificar ejemplos y para hac...
Retinal Pigment Epithelium Cell Alignment on Nanostructured Collagen Matrices
Ulbrich, Stefan; Friedrichs, Jens; Valtink, Monika; Murovski, Simo; Franz, Clemens M.; Müller, Daniel J.; Richard H. W. Funk; Engelmann, Katrin
2014-01-01
We investigated attachment and migration of human retinal pigment epithelial cells (primary, SV40-transfected and ARPE-19) on nanoscopically defined, two-dimensional matrices composed of parallel-aligned collagen type I fibrils. These matrices were used non-cross-linked (native) or after riboflavin/UV-A cross-linking to study cell attachment and migration by time-lapse video microscopy. Expression of collagen type I and IV, MMP-2 and of the collagen-binding integrin subunit α2 were examined b...
[Ecotoxicological bioassays on aquatic sediments: experimental problems of exposure matrices].
Miniero, Roberto; Dellatte, Elena; Lupi, Carlo; Di Domenico, Alessandro
2005-01-01
In this review a discussion on some factors influencing the exposure matrices which, in turn, influences the reliability of ecotoxicological bioassays on aquatic sediments, has been carried out. These factors include the variability induced on sediments by the sampling, storage, handling, and preparative operations. The exposure matrices-sediments in toto, interstitial water and elutriate, can be deeply modified by these actions, which alter the chemicals bioavailability and, therefore, the bioassay meaning. In order to obtain reproducible and scientifically valid data, to be used in the ecological risk assessment, all these factors need to be considered and kept under control.
Positive projections of symmetric matrices and Jordan algebras
DEFF Research Database (Denmark)
Fuglede, Bent; Jensen, Søren Tolver
2013-01-01
An elementary proof is given that the projection from the space of all symmetric p×p matrices onto a linear subspace is positive if and only if the subspace is a Jordan algebra. This solves a problem in a statistical model.......An elementary proof is given that the projection from the space of all symmetric p×p matrices onto a linear subspace is positive if and only if the subspace is a Jordan algebra. This solves a problem in a statistical model....
Random Matrices for Information Processing – A Democratic Vision
DEFF Research Database (Denmark)
Cakmak, Burak
The thesis studies three important applications of random matrices to information processing. Our main contribution is that we consider probabilistic systems involving more general random matrix ensembles than the classical ensembles with iid entries, i.e. models that account for statistical...... dependence between the entries. Specifically, the involved matrices are invariant or fulfill a certain asymptotic freeness condition as their dimensions grow to infinity. Informally speaking, all latent variables contribute to the system model in a democratic fashion – there are no preferred latent variables...
Precise Asymptotics for Random Matrices and Random Growth Models
Institute of Scientific and Technical Information of China (English)
Zhong Gen SU
2008-01-01
The author considers the largest eigenvalues of random matrices from Gaussian unitary ensemble and Laguerre unitary ensemble, and the rightmost charge in certain random growth models.We obtain some precise asymptotics results, which are in a sense similar to the precise asymptotics for sums of independent random variables in the context of the law of large numbers and complete convergence. Our proofs depend heavily upon the upper and lower tail estimates for random matrices and random growth models. The Tracy-Widom distribution plays a central role as well.
THE ALGORITHM AND PROGRAM OF M-MATRICES SEARCH AND STUDY
Directory of Open Access Journals (Sweden)
Y. N. Balonin
2013-05-01
Full Text Available The algorithm and software for search and study of orthogonal bases matrices – minimax matrices (M-matrix are considered. The algorithm scheme is shown, comments on calculation blocks are given, and interface of the MMatrix software system developed with participation of the authors is explained. The results of the universal algorithm work are presented as Hadamard matrices, Belevitch matrices (C-matrices, conference matrices and matrices of even and odd orders complementary and closely related to those ones by their properties, in particular, the matrix of the 22-th order for which there is no C-matrix. Examples of portraits for alternative matrices of the 255-th and the 257-th orders are given corresponding to the sequences of Mersenne and Fermat numbers. A new way to get Hadamard matrices is explained, different from the previously known procedures based on iterative processes and calculations of Lagrange symbols, with theoretical and practical meaning.
Facile hydrothermal synthesis of CeO2 nanopebbles
Indian Academy of Sciences (India)
N Sabari Arul; D Mangalaraj; Jeong In Han
2015-09-01
Cerium oxide (CeO2) nanopebbles have been synthesized using a facile hydrothermal method. X-ray diffraction pattern (XRD) and transmission electron microscopy analyses confirm the presence of CeO2 nanopebbles. XRD shows the formation of cubic fluorite CeO2 and the average particle size estimated from the Scherrer formula was found to be 6.69 nm. X-ray absorption spectrum of CeO2 nanopebbles exhibits two main sharp white lines at 880 and 898 eV due to the spin orbital splitting of 4 and 5. Optical absorption for the synthesized CeO2 nanopebbles exhibited a blue shift (g = 3.35 eV) with respect to the bulk CeO2 (g = 3.19 eV), indicating the existence of quantum confinement effects.
A thermodynamic assessment of Ce-Al system
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
The optimized descriptions of the phase diagram and thermodynamic properties for Ce-Al system have been obtained from experimental thermodynamic and phase diagram data by means of the computer program THERMO-CALC based on the least squares method, using models for the Gibbs energy of individual phases. The system contains five intermetallic compounds. The calculated standard enthalpies of Ce3Al, CeAl, CeAl2, CeAl3 and Ce3Al11 are -26.7, -48.9, -48.4, -44.0 and -41.7 kJ/mol, respectively. A consistent set of thermodynamic parameters was derived. The optimized and experimental data are in good agreement.
Directory of Open Access Journals (Sweden)
Xiongfei Zou
2013-01-01
Full Text Available This paper introduces a novel neural-network-based approach for extracting some eigenpairs of real normal matrices of order n. Based on the proposed algorithm, the eigenvalues that have the largest and smallest modulus, real parts, or absolute values of imaginary parts can be extracted, respectively, as well as the corresponding eigenvectors. Although the ordinary differential equation on which our proposed algorithm is built is only n-dimensional, it can succeed to extract n-dimensional complex eigenvectors that are indeed 2n-dimensional real vectors. Moreover, we show that extracting eigen-pairs of general real matrices can be reduced to those of real normal matrices by employing the norm-reducing skill. Numerical experiments verified the computational capability of the proposed algorithm.
Dissolution of Ce from Cd Solution Containing U/Ce Elements by Electrolysis
Energy Technology Data Exchange (ETDEWEB)
Kim, Si Hyung; Kim, Gha-Young; Lee, Seung-jai; Kim, Taek-Jin; Paek, Seungwoo; Ahn, Do-Hee [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)
2015-10-15
The U-TRU metal alloy can be supplied by the Pyroprocessing, specifically UTRU recovery process using liquid cadmium cathode (LCC). In a certain case, a lot of rare earth (RE) element could be recovered on the LCC with the TRU element during the Pyroprocessing when the concentration of RE ions is higher than that of the TRU ions in the salt. In this case, most of the RE element needs to be removed from the Cd solution containing U/TRU/RE elements. RAR(Residual Actinides Recovery) technique used the mixed electrolytic-chemical process. In this study, only electrolysis technique was utilized to remove Ce element from Cd solution containing U/Ce elements. U-TRU alloy having less impurity is necessary for the fabrication of SFR fuel and these U-TRU elements can be prepared by Pyroprocessing. Electrolytic method was used to reduce the amount of Ce elements from the Cd solution containing U/Ce elements. It is judged from this study that electrolytic dissolution can be one of the methods to reduce RE elements from the Cd solution containing U-TRU-RE elements.
Windows CE自定制Shell%Customizing Windows CE Shell
Institute of Scientific and Technical Information of China (English)
覃朗; 雷跃明
2010-01-01
Shell是用户访问操作系统的接口.Shell开发在Windows CE操作系统开发中占据一定的重要性.对Windows CE Shell进行了概述,并通过建立Shell模型,讲述如何自定制Windows CE Shell和定制Shell必须注意的问题,对Windows CE Shell的定制进行深入研究.
Inverted opal luminescent Ce-doped silica glasses
Directory of Open Access Journals (Sweden)
R. Scotti
2006-01-01
Full Text Available Inverted opal Ce-doped silica glasses (Ce : Si molar ratio 1 ⋅ 10−3 were prepared by a sol-gel method using opals of latex microspheres as templates. The rare earth is homogeneously dispersed in silica host matrix, as evidenced by the absence of segregated CeO2, instead present in monolithic Ce-doped SG with the same cerium content. This suggests that the nanometric dimensions of bridges and junctions of the host matrix in the inverted opal structures favor the RE distribution avoiding the possible segregation of CeO2.
Martínez Buitrago, Diana Isabel
2010-01-01
En este trabajo, se realiza un estudio de la dimensión del álgebra generada por dos matrices conmutantes mediante dos métodos diferentes; en el primero se usan herramientas del álgebra lineal y en el segundo se usan razonamientos de la geometría algebraica. Además, se realiza un estudio de la irreducibilidad de la variedad de m-uplas de matrices conmutantes de tamaño n x n para valores de m y n particulares. / Abstract. In this work, it was made a study of the dimension of the algebra generat...
Valence Fluctuations in CeCo2 and Ti-Doped CeCo2
Öner, Yıldırhan
2016-12-01
We report on the magnetic measurements of polycrystalline samples of CeCo2 and CeCo(2-x)Ti x (x = 0.01, 0.02, 0.03, 0.04, and 0.05) which have been synthesized by an arc melting technique. All these compounds crystallize into the face-centered cubic (FCC) structure with the Fd bar{3} m space group. The lattice parameter decreases linearly with increasing Ti content from 7.15808(5) Å for x = 0 (CeCo2) to 7.15231(7) Å for x = 0.05. The magnetic behavior of these compounds has been investigated in the temperature range 5-400 K. The zero field-cooled (ZFC) and field-cooled magnetization (FC) curves show irreversibility below T = 400 K. This result indicates that an inhomogeneous, dynamic magnetic state exists over a wide temperature range. The magnetic susceptibility for both ZFC and FC cases initially decreases with Ti content and then increases with further Ti addition. This behavior is interpreted in terms of band magnetism in the presence of magnetic clusters. This result indicates that the magnetic inhomogeneity of these alloys becomes dominant over a wide temperature range. The observed temperature dependence of the magnetic susceptibility leads us to suggest that these compounds are in a mixed-valence state of the magnetic Ce3+ ions and non-magnetic Ce4+ ions. This fact allows us to successfully interpret the ZFC magnetic susceptibility data with the two-level ionic inter-configuration fluctuations model. We also observe that the magnetic susceptibility increases by the addition of Ti, as evidenced by the enhancement of the formation of magnetic Co clusters due to local disorder. Finally, the magnetic state below the Curie temperatures are discussed based on Griffiths-like behavior.
Analytical stiffness matrices with Green-Lagrange strain measure
DEFF Research Database (Denmark)
Pedersen, Pauli
2005-01-01
Separating the dependence on material and stress/strain state from the dependence on initial geometry, we obtain analytical secant and tangent stiffness matrices. For the case of a linear displacement triangle with uniform thickness and uniform constitutive behaviour closed-form results are listed...
Matrices Totally Positive Relative to a General Tree
Costas-Santos, R S
2010-01-01
In this paper we prove that for a general tree $T$, if $A$ is T-TP, all the submatrices of $A$ associated with the deletion of pendant vertices are $P$-matrices, and $\\det A>0$, then the smallest eigenvalue has an eigenvector signed according to $T$.
State dependent matrices and balanced energy functions for nonlinear systems
Scherpen, Jacquelien M.A.; Gray, W. Steven
2000-01-01
The nonlinear extension of the balancing procedure requires the case of state dependent quadratic forms for the energy functions, i.e., the nonlinear extensions of the linear Gramians are state dependent matrices. These extensions have some interesting ambiguities that do not occur in the linear cas
Reduction of asymmetry by rank-one matrices
Ten Berge, J.M.F.
1997-01-01
Gower has shown how to partition the sum of squares of an asymmetric matrix into independent parts associated with the symmetric and the skew-symmetric parts of the matrix; and has pointed out that asymmetry can be removed by subtracting certain unit-rank matrices, which improve the symmetry in equa
On the extraction of weights from pairwise comparison matrices
Dijkstra, Theo K.
2013-01-01
We study properties of weight extraction methods for pairwise comparison matrices that minimize suitable measures of inconsistency, 'average error gravity' measures, including one that leads to the geometric row means. The measures share essential global properties with the AHP inconsistency measure
Dirac Matrices and Feynman’s Rest of the Universe
Directory of Open Access Journals (Sweden)
Young S. Kim
2012-10-01
Full Text Available There are two sets of four-by-four matrices introduced by Dirac. The first set consists of fifteen Majorana matrices derivable from his four γ matrices. These fifteen matrices can also serve as the generators of the group SL(4, r. The second set consists of ten generators of the Sp(4 group which Dirac derived from two coupled harmonic oscillators. It is shown possible to extend the symmetry of Sp(4 to that of SL(4, r if the area of the phase space of one of the oscillators is allowed to become smaller without a lower limit. While there are no restrictions on the size of phase space in classical mechanics, Feynman’s rest of the universe makes this Sp(4-to-SL(4, r transition possible. The ten generators are for the world where quantum mechanics is valid. The remaining five generators belong to the rest of the universe. It is noted that the groups SL(4, r and Sp(4 are locally isomorphic to the Lorentz groups O(3, 3 and O(3, 2 respectively. This allows us to interpret Feynman’s rest of the universe in terms of space-time symmetry.
More about unphysical zeroes in quark mass matrices
Emmanuel-Costa, David; González Felipe, Ricardo
2017-01-01
We look for all weak bases that lead to texture zeroes in the quark mass matrices and contain a minimal number of parameters in the framework of the standard model. Since there are ten physical observables, namely, six nonvanishing quark masses, three mixing angles and one CP phase, the maximum number of texture zeroes in both quark sectors is altogether nine. The nine zero entries can only be distributed between the up- and down-quark sectors in matrix pairs with six and three texture zeroes or five and four texture zeroes. In the weak basis where a quark mass matrix is nonsingular and has six zeroes in one sector, we find that there are 54 matrices with three zeroes in the other sector, obtainable through right-handed weak basis transformations. It is also found that all pairs composed of a nonsingular matrix with five zeroes and a nonsingular and nondecoupled matrix with four zeroes simply correspond to a weak basis choice. Without any further assumptions, none of these pairs of up- and down-quark mass matrices has physical content. It is shown that all non-weak-basis pairs of quark mass matrices that contain nine zeroes are not compatible with current experimental data. The particular case of the so-called nearest-neighbour-interaction pattern is also discussed.
Technologies for detecting botulinum neurotoxins in biological and environmental matrices
Biomonitoring of food and environmental matrices is critical for the rapid and sensitive diagnosis, treatment, and prevention of diseases caused by toxins. The United States Centers for Disease Control and Prevention (CDC) has noted that toxins from bacteria, fungi, algae, and plants present an ongo...
Advances in detection of antipsychotics in biological matrices.
Patteet, Lisbeth; Cappelle, Delphine; Maudens, Kristof E; Crunelle, Cleo L; Sabbe, Bernard; Neels, Hugo
2015-02-20
Measuring antipsychotic concentrations in human matrices is important for both therapeutic drug monitoring and forensic toxicology. This review provides a critical overview of the analytical methods for detection and quantification of antipsychotics published in the last four years. Focus lies on advances in sample preparation, analytical techniques and alternative matrices. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is used most often for quantification of antipsychotics. This sensitive technique makes it possible to determine low concentrations not only in serum, plasma or whole blood, but also in alternative matrices like oral fluid, dried blood spots, hair, nails and other body tissues. Current literature on analytical techniques for alternative matrices is still limited and often requires a more thorough validation including a comparison between conventional and alternative results to determine their actual value. Ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) makes it possible to quantify a high amount of compounds within a shorter run time. This technique is widely used for multi-analyte methods. Only recently, high-resolution mass spectrometry has gained importance when a combination of screening of (un)known metabolites, and quantification is required.
Convergence of GAOR Iterative Method with Strictly Diagonally Dominant Matrices
Directory of Open Access Journals (Sweden)
Guangbin Wang
2011-01-01
Full Text Available We discuss the convergence of GAOR method for linear systems with strictly diagonally dominant matrices. Moreover, we show that our results are better than ones of Darvishi and Hessari (2006, Tian et al. (2008 by using three numerical examples.
Variation in Raven's Progressive Matrices Scores across Time and Place
Brouwers, Symen A.; Van de Vijver, Fons J. R.; Van Hemert, Dianne A.
2009-01-01
The paper describes a cross-cultural and historical meta-analysis of Raven's Progressive Matrices. Data were analyzed of 798 samples from 45 countries (N = 244,316), which were published between 1944 and 2003. Country-level indicators of educational permeation (which involves a broad set of interrelated educational input and output factors that…
Automorphisms of semigroups of invertible matrices with nonnegative integer elements
Energy Technology Data Exchange (ETDEWEB)
Semenov, Pavel P [M. V. Lomonosov Moscow State University, Faculty of Mechanics and Mathematics, Moscow (Russian Federation)
2012-09-30
Let G{sub n}(Z) be the subsemigroup of GL{sub n}(Z) consisting of the matrices with nonnegative integer coefficients. In the paper, the automorphisms of this semigroup are described for n{>=}2. Bibliography: 5 titles.
Elements of the Theory of Generalized Inverses for Matrices.
Cline, Randall E.
This document is designed to provide a concise introduction to the theory of generalized inverses of matrices that is accessible to undergraduate mathematics majors. The approach used is to: (1) develop the material in terms of full-rank factorizations and to relegate all discussions using eigenvalues and eigenvectors to exercises, and (2) include…
Algorithm Engineering for Optimal Alignment of Protein Structure Distance Matrices
Wohlers, I.; Andonov, R.; Klau, G.W.
2011-01-01
Protein structural alignment is an important problem in computational biology. In this paper, we present first successes on provably optimal pairwise alignment of protein inter-residue distance matrices, using the popular DALI scoring function. We introduce the structural alignment problem formally,
Average Density of States for Hermitian Wigner Matrices
Maltsev, Anna
2010-01-01
We consider ensembles of $N \\times N$ Hermitian Wigner matrices, whose entries are (up to the symmetry constraints) independent and identically distributed random variables. Assuming sufficient regularity for the probability density function of the entries, we show that the expectation of the density of states on {\\it arbitrarily} small intervals converges to the semicircle law, as $N$ tends to infinity.
Equilibrium states of the pressure function for products of matrices
Feng, De-Jun
2010-01-01
Let $\\{M_i\\}_{i=1}^\\ell$ be a non-trivial family of $d\\times d$ complex matrices, in the sense that for any $n\\in \\N$, there exists $i_1... i_n\\in \\{1,..., \\ell\\}^n$ such that $M_{i_1}... M_{i_n}\
A fast algorithm for LR-2 factorization of Toeplitz matrices
Glentis, George-Othon
1995-01-01
In this paper a new order recursive algorithm for the efficient −1 factorization of Toeplitz matrices is described. The proposed algorithm can be seen as a fast modified Gram-Schmidt method which recursively computes the orthonormal columns i, i = 1,2, …,p, of , as well as the elements of R−1, of
Quantitative mass spectrometry of unconventional human biological matrices
Dutkiewicz, Ewelina P.; Urban, Pawel L.
2016-10-01
The development of sensitive and versatile mass spectrometric methodology has fuelled interest in the analysis of metabolites and drugs in unconventional biological specimens. Here, we discuss the analysis of eight human matrices-hair, nail, breath, saliva, tears, meibum, nasal mucus and skin excretions (including sweat)-by mass spectrometry (MS). The use of such specimens brings a number of advantages, the most important being non-invasive sampling, the limited risk of adulteration and the ability to obtain information that complements blood and urine tests. The most often studied matrices are hair, breath and saliva. This review primarily focuses on endogenous (e.g. potential biomarkers, hormones) and exogenous (e.g. drugs, environmental contaminants) small molecules. The majority of analytical methods used chromatographic separation prior to MS; however, such a hyphenated methodology greatly limits analytical throughput. On the other hand, the mass spectrometric methods that exclude chromatographic separation are fast but suffer from matrix interferences. To enable development of quantitative assays for unconventional matrices, it is desirable to standardize the protocols for the analysis of each specimen and create appropriate certified reference materials. Overcoming these challenges will make analysis of unconventional human biological matrices more common in a clinical setting. This article is part of the themed issue 'Quantitative mass spectrometry'.
Wigner law for matrices with dependent entries - a perturbative approach
Krajewski, T; Vu, D L
2016-01-01
We show that Wigner semi-circle law holds for Hermitian matrices with dependent entries, provided the deviation of the cumulants from the normalised Gaussian case obeys a simple power law bound in the size of the matrix. To establish this result, we use replicas interpreted as a zero-dimensional quantum field theoretical model whose effective potential obey a renormalisation group equation.
A simple procedure for the comparison of covariance matrices.
Garcia, Carlos
2012-11-21
Comparing the covariation patterns of populations or species is a basic step in the evolutionary analysis of quantitative traits. Here I propose a new, simple method to make this comparison in two population samples that is based on comparing the variance explained in each sample by the eigenvectors of its own covariance matrix with that explained by the covariance matrix eigenvectors of the other sample. The rationale of this procedure is that the matrix eigenvectors of two similar samples would explain similar amounts of variance in the two samples. I use computer simulation and morphological covariance matrices from the two morphs in a marine snail hybrid zone to show how the proposed procedure can be used to measure the contribution of the matrices orientation and shape to the overall differentiation. I show how this procedure can detect even modest differences between matrices calculated with moderately sized samples, and how it can be used as the basis for more detailed analyses of the nature of these differences. The new procedure constitutes a useful resource for the comparison of covariance matrices. It could fill the gap between procedures resulting in a single, overall measure of differentiation, and analytical methods based on multiple model comparison not providing such a measure.
Cleaning large correlation matrices: Tools from Random Matrix Theory
Bun, Joël; Bouchaud, Jean-Philippe; Potters, Marc
2017-01-01
This review covers recent results concerning the estimation of large covariance matrices using tools from Random Matrix Theory (RMT). We introduce several RMT methods and analytical techniques, such as the Replica formalism and Free Probability, with an emphasis on the Marčenko-Pastur equation that provides information on the resolvent of multiplicatively corrupted noisy matrices. Special care is devoted to the statistics of the eigenvectors of the empirical correlation matrix, which turn out to be crucial for many applications. We show in particular how these results can be used to build consistent "Rotationally Invariant" estimators (RIE) for large correlation matrices when there is no prior on the structure of the underlying process. The last part of this review is dedicated to some real-world applications within financial markets as a case in point. We establish empirically the efficacy of the RIE framework, which is found to be superior in this case to all previously proposed methods. The case of additively (rather than multiplicatively) corrupted noisy matrices is also dealt with in a special Appendix. Several open problems and interesting technical developments are discussed throughout the paper.
Normative data for Raven's Coloured Progressive Matrices scale in Yemen.
Khaleefa, Omar; Lynn, Richard
2008-08-01
Results are reported for a standardization sample of 986 6- to 1-yr.-olds for the Coloured Progressive Matrices in Yemen. Younger children performed better than older children relative to British norms, and there was no significant sex difference in means or variability. In relation to a British IQ of 100 (SD=15), the sample obtained an average IQ of approximately 81.
Raven's Matrices Performance in Down Syndrome: Evidence of Unusual Errors
Gunn, Deborah M.; Jarrold, Christopher
2004-01-01
The aim of this study was to investigate the types of errors produced by three participant groups (individuals with Down syndrome, with moderate learning disability, and typically developing children) whilst completing the Raven's Coloured Progressive Matrices task. An analysis of error categories revealed that individuals with Down syndrome…
A Kenya Standardization of the Raven's Coloured Progressive Matrices.
Costenbader, Virginia; Ngari, Stephen Mbugua
2001-01-01
Establishes a Kenyan standardization of the Raven's Coloured Progressive Matrices (RCPM), a nonverbal instrument widely used to assess academic aptitude in young children. Data was gathered from a sample of 1,370 children between the ages of 6 and 10 years. Using the current data, the RCPM appears to be a reliable and valid instrument for use in…
A simple procedure for the comparison of covariance matrices
2012-01-01
Background Comparing the covariation patterns of populations or species is a basic step in the evolutionary analysis of quantitative traits. Here I propose a new, simple method to make this comparison in two population samples that is based on comparing the variance explained in each sample by the eigenvectors of its own covariance matrix with that explained by the covariance matrix eigenvectors of the other sample. The rationale of this procedure is that the matrix eigenvectors of two similar samples would explain similar amounts of variance in the two samples. I use computer simulation and morphological covariance matrices from the two morphs in a marine snail hybrid zone to show how the proposed procedure can be used to measure the contribution of the matrices orientation and shape to the overall differentiation. Results I show how this procedure can detect even modest differences between matrices calculated with moderately sized samples, and how it can be used as the basis for more detailed analyses of the nature of these differences. Conclusions The new procedure constitutes a useful resource for the comparison of covariance matrices. It could fill the gap between procedures resulting in a single, overall measure of differentiation, and analytical methods based on multiple model comparison not providing such a measure. PMID:23171139
Higgs-boson masses and mixing matrices in the NMSSM
DEFF Research Database (Denmark)
Drechsel, P.; Gröber, R.; Heinemeyer, S.
2017-01-01
We analyze the Higgs-boson masses and mixing matrices in the NMSSM based on an on-shell (OS) renormalization of the gauge-boson and Higgs-boson masses and the parameters of the top/scalar top sector. We compare the implementation of the OS calculations in the codes NMSSMCALC and NMSSM-FeynHiggs up...
A Hypothetical Learning Trajectory for Conceptualizing Matrices as Linear Transformations
Andrews-Larson, Christine; Wawro, Megan; Zandieh, Michelle
2017-01-01
In this paper, we present a hypothetical learning trajectory (HLT) aimed at supporting students in developing flexible ways of reasoning about matrices as linear transformations in the context of introductory linear algebra. In our HLT, we highlight the integral role of the instructor in this development. Our HLT is based on the "Italicizing…
Free Fermionic Elliptic Reflection Matrices and Quantum Group Invariance
Cuerno, R
1993-01-01
Elliptic diagonal solutions for the reflection matrices associated to the elliptic $R$ matrix of the eight vertex free fermion model are presented. They lead through the second derivative of the open chain transfer matrix to an XY hamiltonian in a magnetic field which is invariant under a quantum deformed Clifford--Hopf algebra.
A simple procedure for the comparison of covariance matrices
Directory of Open Access Journals (Sweden)
Garcia Carlos
2012-11-01
Full Text Available Abstract Background Comparing the covariation patterns of populations or species is a basic step in the evolutionary analysis of quantitative traits. Here I propose a new, simple method to make this comparison in two population samples that is based on comparing the variance explained in each sample by the eigenvectors of its own covariance matrix with that explained by the covariance matrix eigenvectors of the other sample. The rationale of this procedure is that the matrix eigenvectors of two similar samples would explain similar amounts of variance in the two samples. I use computer simulation and morphological covariance matrices from the two morphs in a marine snail hybrid zone to show how the proposed procedure can be used to measure the contribution of the matrices orientation and shape to the overall differentiation. Results I show how this procedure can detect even modest differences between matrices calculated with moderately sized samples, and how it can be used as the basis for more detailed analyses of the nature of these differences. Conclusions The new procedure constitutes a useful resource for the comparison of covariance matrices. It could fill the gap between procedures resulting in a single, overall measure of differentiation, and analytical methods based on multiple model comparison not providing such a measure.
Structure of Dirac matrices and invariants for nonlinear Dirac equations
2004-01-01
We present invariants for nonlinear Dirac equations in space-time ${\\mathbb R}^{n+1}$, by which we prove that a special choice of the Cauchy data yields free solutions. Our argument works for Klein-Gordon-Dirac equations with Yukawa coupling as well. Related problems on the structure of Dirac matrices are studied.
Schur complements of matrices with acyclic bipartite graphs
DEFF Research Database (Denmark)
Britz, Thomas Johann; Olesky, D.D.; van den Driessche, P.
2005-01-01
Bipartite graphs are used to describe the generalized Schur complements of real matrices having nos quare submatrix with two or more nonzero diagonals. For any matrix A with this property, including any nearly reducible matrix, the sign pattern of each generalized Schur complement is shown to be ...
Soft matrices on soft multisets in an optimal decision process
Coskun, Arzu Erdem; Aras, Cigdem Gunduz; Cakalli, Huseyin; Sonmez, Ayse
2016-08-01
In this paper, we introduce a concept of a soft matrix on a soft multiset, and investigate how to use soft matrices to solve decision making problems. An algorithm for a multiple choose selection problem is also provided. Finally, we demonstrate an illustrative example to show the decision making steps.
Collagenous matrices as release carriers of exogenous growth factors.
Kanematsu, Akihiro; Yamamoto, Shingo; Ozeki, Makoto; Noguchi, Tetsuya; Kanatani, Isao; Ogawa, Osamu; Tabata, Yasuhiko
2004-08-01
We have investigated the use of natural and synthetic collagenous matrices as carriers of exogenous growth factors. A bladder acellular matrix (BAM) was processed from rat bladder and compared with sponge matrix of porcine type 1 collagen. The lyophilized matrices were rehydrated by the aqueous solutions of basic fibroblast growth factor (bFGF), hepatocyte growth factor (HGF), platelet derived growth factor-BB (PDGF-BB), vascular endothelial growth factor (VEGF), insulin like growth factor-1 (IGF-1) and heparin binding epidermal growth factor-like growth factor (HB-EGF), to obtain the matrix incorporating each growth factor. The rehydration method enabled the growth factor protein to distribute into the matrix homogeneously. In vivo release test in the mouse subcutis revealed that, the property of BAM for growth factor release was similar to that of collagen sponge. Among the growth factors examined, bFGF release was the most sustained, followed by HGF and PDGF-BB. bFGF released from the two matrices showed similar in vivo angiogenic activity at the mouse subcutis in a dose-dependent manner. These findings demonstrate that the collagenous matrices function as release carriers of growth factors. This feature is promising to create a scaffold, which has a nature to control the tissue regeneration actively.
On the nonnegative inverse eigenvalue problem of traditional matrices
Directory of Open Access Journals (Sweden)
Alimohammad Nazari
2014-07-01
Full Text Available In this paper, at first for a given set of real or complex numbers $\\sigma$ with nonnegativesummation, we introduce some special conditions that with them there is no nonnegativetridiagonal matrix in which $\\sigma$ is its spectrum. In continue we present some conditions forexistence such nonnegative tridiagonal matrices.
About limit matrices of finite-state Markov chains
Nieuwenhuis, J.W.
1997-01-01
By means of the concept of group inverse of a matrix we study limiting properties of a collection of stochastic matrices {P-epsilon, epsilon is an element of [0, 1]}, where For All epsilon is an element of [0, 1], P-epsilon is an element of R(nxn) and where P-0 = lim(epsilon-->0)P(epsilon). (C) Else
Designer matrices for intestinal stem cell and organoid culture
Gjorevski, Nikolce; Sachs, Norman; Manfrin, Andrea; Giger, Sonja; Bragina, Maiia E; Ordóñez-Morán, Paloma; Clevers, Hans; Lutolf, Matthias P
2016-01-01
Epithelial organoids recapitulate multiple aspects of real organs, making them promising models of organ development, function and disease. However, the full potential of organoids in research and therapy has remained unrealized, owing to the poorly defined animal-derived matrices in which they are
Public Key Cryptography Based on Ergodic Matrices over Finite Field
Institute of Scientific and Technical Information of China (English)
PEI Shihui; ZHAO Hongwei; ZHAO Yongzhe
2006-01-01
A new public key encryption scheme is proposed in this paper, which is based on a hard problem over ergodic matrices. The security of this scheme is equal to the MQ-problem: multivariate quadratic equations over finite fields. This problem has been shown to be NP-complete and can' be solved with polynomial time algorithm.
Products of rectangular random matrices: singular values and progressive scattering.
Akemann, Gernot; Ipsen, Jesper R; Kieburg, Mario
2013-11-01
We discuss the product of M rectangular random matrices with independent Gaussian entries, which have several applications, including wireless telecommunication and econophysics. For complex matrices an explicit expression for the joint probability density function is obtained using the Harish-Chandra-Itzykson-Zuber integration formula. Explicit expressions for all correlation functions and moments for finite matrix sizes are obtained using a two-matrix model and the method of biorthogonal polynomials. This generalizes the classical result for the so-called Wishart-Laguerre Gaussian unitary ensemble (or chiral unitary ensemble) at M=1, and previous results for the product of square matrices. The correlation functions are given by a determinantal point process, where the kernel can be expressed in terms of Meijer G-functions. We compare the results with numerical simulations and known results for the macroscopic level density in the limit of large matrices. The location of the end points of support for the latter are analyzed in detail for general M. Finally, we consider the so-called ergodic mutual information, which gives an upper bound for the spectral efficiency of a MIMO communication channel with multifold scattering.
Controlled growth factor release from synthetic extracellular matrices
Lee, Kuen Yong; Peters, Martin C.; Anderson, Kenneth W.; Mooney, David J.
2000-12-01
Polymeric matrices can be used to grow new tissues and organs, and the delivery of growth factors from these matrices is one method to regenerate tissues. A problem with engineering tissues that exist in a mechanically dynamic environment, such as bone, muscle and blood vessels, is that most drug delivery systems have been designed to operate under static conditions. We thought that polymeric matrices, which release growth factors in response to mechanical signals, might provide a new approach to guide tissue formation in mechanically stressed environments. Critical design features for this type of system include the ability to undergo repeated deformation, and a reversible binding of the protein growth factors to polymeric matrices to allow for responses to repeated stimuli. Here we report a model delivery system that can respond to mechanical signalling and upregulate the release of a growth factor to promote blood vessel formation. This approach may find a number of applications, including regeneration and engineering of new tissues and more general drug-delivery applications.
Tonai, Hironori; Sasabe, Norimasa; Uozumi, Takayuki; Kawamura, Naomi; Mizumaki, Masaichiro
2017-09-01
Partial fluorescence yield (PFY) spectroscopy, which corresponds to a high-resolution version of the X-ray absorption spectroscopy (XAS), is experimentally performed at the Ce L3 edge of CeO2, and the result is theoretically analyzed using an impurity Anderson model (IAM). In order to estimate the Ce 4f-5d interaction Ufd, we employ a semi-empirical IAM framework based on the local density approximation+U method; Slater-Koster parameters describing the valence of CeO2 are estimated by band mapping within the linear combination of atomic orbitals scheme, and the resulting realistic valence structure is considered in the IAM analysis. The global structure of the PFY-XAS result, which consists of the Ce 2p3/2 → 5d dipole transition and the Ce 2p3/2 → 4f quadrupole transition, is excellently reproduced by the calculation. The Ufd value is estimated to be 3.0 eV. We emphasize that the sensitivity of PFY-XAS to Ufd makes it a good ruler for obtaining the Ufd values of Ce compounds.
MCD study on Ce-C{sub 82} and Ce{sub 2}-C{sub 80} in the soft-X-ray region
Energy Technology Data Exchange (ETDEWEB)
Ishikawa, Jun [Department of Physics, Tokyo Metropolitan University, Hachioji-shi, Tokyo (Japan); Miyahara, Tsuneaki, E-mail: miyaharat@fc.jwu.ac.jp [Department of Mathematical and Physical Sciences, Japan Women' s University, 2-8-1 Mejirodai, Bunkyo-ku, Tokyo 112-8681 (Japan); Hirato, Yasuharu; Ishii, Hiroyoshi [Department of Physics, Tokyo Metropolitan University, Hachioji-shi, Tokyo (Japan); Kodama, Takeshi; Kikuchi, Koichi [Department of Chemistry, Tokyo Metropolitan University, Hachioji-shi, Tokyo (Japan); Nakamura, Tesuya; Kodama, Kenji [Spring-8, Sayo-gun, Hyogo-ken (Japan); Asakura, Daisuke; Koide, Tsuneharu [Photon Factory, High Energy Accelerator Research Organization, KEK, Tsukuba-shi, Ibaraki-ken (Japan)
2011-04-15
Highlights: {yields} We measured the temperature dependence of MCD spectra on Ce-C{sub 82} and Ce{sub 2}-C{sub 80}. {yields} We found that Ce 4f moments are antiferromagnetic in Ce-C{sub 82}. {yields} But they are ferromagnetic in Ce{sub 2}-C{sub 80}. {yields} The 4f moments are much smaller than the Hund-ground-state value. {yields} This is caused by a strong crystal field exerted by the carbon cage. - Abstract: We have measured the temperature dependence of MCD spectra on Ce-C{sub 82} and Ce{sub 2}-C{sub 80} in the Ce 3d-4f excitation region. The results show that Ce-C{sub 82} has antiferromagnetic interaction while Ce{sub 2}-C{sub 80} has ferromagnetic interaction between Ce magnetic moments which are much smaller than the Hund-ground-state values.
Institute of Scientific and Technical Information of China (English)
Zheng Xiucheng; Han Dongzhan; Wang Shuping; Zhang Shoumin; Wang Shurong; Huang Weiping; Wu Shihua
2005-01-01
CeO2 was synthesized via sol-gel process and used as supporter to prepare CuO/CeO2, Cu/CeO2 catalysts by impregnation method. The catalytic properties and characterization of CeO2, CuO/CeO2 and Cu/CeO2 catalysts were examined by means of a microreactor-GC system, HRTEM, XRD, TPR and XPS techniques. The results show that CuO has not catalytic activity and the activity of CeO2 is quite low for CO oxidation. However, the catalytic activity of CuO/CeO2 and Cu/CeO2 catalysts increases significantly. Furthermore, the activity of CuO/CeO2 is higher than that of Cu/CeO2 catalysts.
ON SELF-INVERSE BINARY MATRICES OVER THE BINARY GALOIS FIELD
Directory of Open Access Journals (Sweden)
Ali Muhammad Ali Rushdi
2013-01-01
Full Text Available An important class of square binary matrices over the simplest finite or Galois Field GF(2 is the class of involutory or Self-Inverse (SI matrices. These matrices are of significant utility in prominent engineering applications such as the study of the Preparata Transformation or the analysis of synchronous Boolean Networks. Therefore, it is essential to devise appropriate methods, not only for understanding the properties of these matrices, but also for characterizing and constructing them. We survey square binary matrices of orders 1, 2 and 3 to identify primitive SI matrices among them. Larger SI matrices are constructed as (a the direct sum, or (b the Kronecker product, of smaller ones. Illustrative examples are given to demonstrate the construction and properties of binary SI matrices. The intersection of the sets of SI and permutation binary matrices is studied. We also study higher-order SI binary matrices and describe them via recursive relations or Kronecker products. Our work culminates in an exposition of the two most common representations of Boolean functions via two types of Boolean SI matrices. A better understanding of the properties and methods of constructing SI binary matrices over GF (2 is achieved. A clearer picture is attained about the utility of binary matrices in the representation of Boolean functions.
Ferraro, Daniela; Tredici, Ilenia G; Ghigna, Paolo; Castillio-Michel, Hiram; Falqui, Andrea; Di Benedetto, Cristiano; Alberti, Giancarla; Ricci, Vittorio; Anselmi-Tamburini, Umberto; Sommi, Patrizia
2017-01-26
CeO2 nanoparticles (CNPs) have been investigated as promising antioxidant agents with significant activity in the therapy of diseases involving free radicals or oxidative stress. However, the exact mechanism responsible for CNP activity has not been completely elucidated. In particular, in situ evidence of modification of the oxidative state of CNPs in human cells and their evolution during cell internalization and subsequent intracellular distribution has never been presented. In this study we investigated modification of the Ce(iii)/Ce(iv) ratio following internalization in human cells by X-ray absorption near edge spectroscopy (XANES). From this analysis on cell pellets, we observed that CNPs incubated for 24 h showed a significant increase in Ce(iii). By coupling on individual cells synchrotron micro-X-ray fluorescence (μXRF) with micro-XANES (μXANES) we demonstrated that the Ce(iii)/Ce(iv) ratio is also dependent on CNP intracellular localization. The regions with the highest CNP concentrations, suggested to be endolysosomes by transmission electron microscopy, were characterized by Ce atoms in the Ce(iv) oxidation state, while a higher Ce(iii) content was observed in regions surrounding these areas. These observations suggest that the interaction of CNPs with cells involves a complex mechanism in which different cellular areas play different roles.
Ferraro, Daniela
2017-01-09
CeO2 nanoparticles (CNPs) have been investigated as promising antioxidant agents with significant activity in the therapy of diseases involving free radicals or oxidative stress. However, the exact mechanism responsible for CNP activity has not been completely elucidated. In particular, in situ evidence of modification of the oxidative state of CNPs in human cells and their evolution during cell internalization and subsequent intracellular distribution has never been presented. In this study we investigated modification of the Ce(iii)/Ce(iv) ratio following internalization in human cells by X-ray absorption near edge spectroscopy (XANES). From this analysis on cell pellets, we observed that CNPs incubated for 24 h showed a significant increase in Ce(iii). By coupling on individual cells synchrotron micro-X-ray fluorescence (μXRF) with micro-XANES (μXANES) we demonstrated that the Ce(iii)/Ce(iv) ratio is also dependent on CNP intracellular localization. The regions with the highest CNP concentrations, suggested to be endolysosomes by transmission electron microscopy, were characterized by Ce atoms in the Ce(iv) oxidation state, while a higher Ce(iii) content was observed in regions surrounding these areas. These observations suggest that the interaction of CNPs with cells involves a complex mechanism in which different cellular areas play different roles.
Oxidation driven decomposition of CeNbO4 in pure oxygen
Vullum, Fride; Grande, Tor
2008-01-01
CeNbO4 possess oxygen hyper-stoichiometry at ambient and moderate temperature. At elevated temperature CeNbO4+δ is thermally reduced to near stoichiometric CeNbO4 accompanied by a structural phase transition. Above the phase transition temperature re-oxidation of the material occurred in pure oxygen atmosphere, and in-situ X-ray diffraction revealed that CeNbO4 decomposed to CeO2 and CeNb3O9. Upon further heating CeNbO4 reappeared by a solid state reaction between CeO2 and CeNb3O9. The presen...
Polymer Percolation Threshold in Multi-Component HPMC Matrices Tablets
Directory of Open Access Journals (Sweden)
Maryam Maghsoodi
2011-06-01
Full Text Available Introduction: The percolation theory studies the critical points or percolation thresholds of the system, where onecomponent of the system undergoes a geometrical phase transition, starting to connect the whole system. The application of this theory to study the release rate of hydrophilic matrices allows toexplain the changes in release kinetics of swellable matrix type system and results in a clear improvement of the design of controlled release dosage forms. Methods: In this study, the percolation theory has been applied to multi-component hydroxypropylmethylcellulose (HPMC hydrophilic matrices. Matrix tablets have been prepared using phenobarbital as drug,magnesium stearate as a lubricant employing different amount of lactose and HPMC K4M as a fillerandmatrix forming material, respectively. Ethylcelullose (EC as a polymeric excipient was also examined. Dissolution studies were carried out using the paddle method. In order to estimate the percolation threshold, the behaviour of the kinetic parameters with respect to the volumetric fraction of HPMC at time zero, was studied. Results: In both HPMC/lactose and HPMC/EC/lactose matrices, from the point of view of the percolation theory, the optimum concentration for HPMC, to obtain a hydrophilic matrix system for the controlled release of phenobarbital is higher than 18.1% (v/v HPMC. Above 18.1% (v/v HPMC, an infinite cluster of HPMC would be formed maintaining integrity of the system and controlling the drug release from the matrices. According to results, EC had no significant influence on the HPMC percolation threshold. Conclusion: This may be related to broad functionality of the swelling hydrophilic matrices.
Applicability of non-invasively collected matrices for human biomonitoring
Directory of Open Access Journals (Sweden)
Nickmilder Marc
2009-03-01
Full Text Available Abstract With its inclusion under Action 3 in the Environment and Health Action Plan 2004–2010 of the European Commission, human biomonitoring is currently receiving an increasing amount of attention from the scientific community as a tool to better quantify human exposure to, and health effects of, environmental stressors. Despite the policy support, however, there are still several issues that restrict the routine application of human biomonitoring data in environmental health impact assessment. One of the main issues is the obvious need to routinely collect human samples for large-scale surveys. Particularly the collection of invasive samples from susceptible populations may suffer from ethical and practical limitations. Children, pregnant women, elderly, or chronically-ill people are among those that would benefit the most from non-invasive, repeated or routine sampling. Therefore, the use of non-invasively collected matrices for human biomonitoring should be promoted as an ethically appropriate, cost-efficient and toxicologically relevant alternative for many biomarkers that are currently determined in invasively collected matrices. This review illustrates that several non-invasively collected matrices are widely used that can be an valuable addition to, or alternative for, invasively collected matrices such as peripheral blood sampling. Moreover, a well-informed choice of matrix can provide an added value for human biomonitoring, as different non-invasively collected matrices can offer opportunities to study additional aspects of exposure to and effects from environmental contaminants, such as repeated sampling, historical overview of exposure, mother-child transfer of substances, or monitoring of substances with short biological half-lives.
Biomimetism, biomimetic matrices and the induction of bone formation.
Ripamonti, Ugo
2009-09-01
the induction of bone formation, the emergence of the skeleton, of the vertebrates and of Homo species * Different strategies for the induction of bone formation. Biological significance of redundancy and synergistic induction of bone formation. Biomimetism and biomimetic matrices self-assembling the induction of bone formation The concavity: the shape of life and the induction of bone formation. Influence of geometry on the expression of the osteogenic phenotype. Conclusion and therapeutic perspectives on porous biomimetic matrices with intrinsic osteoinductivity Bone formation by induction initiates by invocation of osteogenic soluble molecular signals of the transforming growth factor-beta (TGF-beta) superfamily; when combined with insoluble signals or substrata, the osteogenic soluble signals trigger the ripple-like cascade of cell differentiation into osteoblastic cell lines secreting bone matrix at site of surgical implantation. A most exciting and novel strategy to initiate bone formation by induction is to carve smart self-inducing geometric concavities assembled within biomimetic constructs. The assembly of a series of repetitive concavities within the biomimetic constructs is endowed with the striking prerogative of differentiating osteoblast-like cells attached to the biomimetic matrices initiating the induction of bone formation as a secondary response. Importantly, the induction of bone formation is initiated without the exogenous application of the osteogenic soluble molecular signals of the TGF-beta superfamily. This manuscript reviews the available data on this fascinating phenomenon, i.e. biomimetic matrices that arouse and set into motion the mammalian natural ability to heal thus constructing biomimetic matrices that in their own right set into motion inductive regenerative phenomena initiating the cascade of bone differentiation by induction biomimetizing the remodelling cycle of the primate cortico-cancellous bone.
Influence of Ce-H bonding on the physical properties of the hydrides CeCoSiH(1.0) and CeCoGeH(1.0).
Chevalier, B; Matar, S F; Ménétrier, M; Marcos, J Sanchez; Fernandez, J Rodriguez
2006-07-05
The hydrides CeCoSiH(1.0) and CeCoGeH(1.0) which crystallize like the parent antiferromagnetic compounds CeCoSi and CeCoGe in the tetragonal CeFeSi-type structure, have been investigated by specific heat and thermoelectric power measurements and (1)H nuclear magnetic resonance (NMR). CeCoSiH(1.0) is an intermediate valence compound whereas CeCoGeH(1.0) can be considered as a nearly trivalent cerium compound. This behaviour is corroborated by the occurrence of a slight broadening of the (1)H NMR signal in the sequence [Formula: see text]. The band structure calculations performed on these hydrides reveal the existence of strong bonding Ce-H interaction, found to be larger in CeCoSiH(1.0) than in CeCoGeH(1.0).
Clavier, Nicolas
2004-01-01
Le phosphate-diphosphate de thorium (beta-PDTU) est actuellement considéré comme une matrice céramique potentielle en vue de l'immobilisation des actinides en formation géologique profonde. Les études réalisées au cours de ce travail reposent sur la synthèse du phosphate-hydrogénophosphate de thorium hydraté (PHPTH) en tant que précurseur du beta-PDT. La structure cristalline du PHPTH a été élucidée puis le mécanisme conduisant à sa transformation en beta-PDT a été établi.Ce dernier met en je...
Qubit representations of the braid groups from generalized Yang-Baxter matrices
Vasquez, Jennifer F.; Wang, Zhenghan; Wong, Helen M.
2016-07-01
Generalized Yang-Baxter matrices sometimes give rise to braid group representations. We identify the exact images of some qubit representations of the braid groups from generalized Yang-Baxter matrices obtained from anyons in the metaplectic modular categories.
Pieper, J.S.; Oosterhof, A.; Dijkstra, Pieter J.; Veerkamp, J.H.; van Kuppevelt, T.H.
1999-01-01
Porous collagen matrices with defined physical, chemical and biological characteristics are interesting materials for tissue engineering. Attachment of glycosaminoglycans (GAGs) may add to these characteristics and valorize collagen. In this study, porous type I collagen matrices were crosslinked
Pieper, J.S.; Oosterhof, A.; Dijkstra, P.J.; Veerkamp, J.H.; Kuppevelt, van T.H.
1999-01-01
Porous collagen matrices with defined physical, chemical and biological characteristics are interesting materials for tissue engineering. Attachment of glycosaminoglycans (GAGs) may add to these characteristics and valorize collagen. In this study, porous type I collagen matrices were crosslinked us
Efficient linear algebra routines for symmetric matrices stored in packed form.
Ahlrichs, Reinhart; Tsereteli, Kakha
2002-01-30
Quantum chemistry methods require various linear algebra routines for symmetric matrices, for example, diagonalization or Cholesky decomposition for positive matrices. We present a small set of these basic routines that are efficient and minimize memory requirements.
Scintillation in LiBaF3(Ce) crystals
Gektin, A; Shiran, N; Voloshinovski, A; Voronova, [No Value; Zimmerer, G
Core-valence, self-trapped exciton and Ce3+-luminescences in pure and doped LiBaF3 crystals were determined on the basis of analysis of the time resolved emission and excitation spectra. It is shown that excitation of Ce-luminescence is caused both by carriers capture at or near activator ions and
Superconductivity and magnetic order in La--Ce alloys
Energy Technology Data Exchange (ETDEWEB)
Wollan, J.J.; Finnemore, D.K.
1971-03-01
Superconductivity and magnetic order have been studied both above and below the Kondo temperature for the La--Ce system. Electrical resistivity measurements on La 0.2, 1.0, 2.0, 3.2, and 4.0 wt. percent Ce have been made from 0.060 to 20.0K.
Scintillation in LiBaF3(Ce) crystals
Gektin, A; Shiran, N; Voloshinovski, A; Voronova, [No Value; Zimmerer, G
1998-01-01
Core-valence, self-trapped exciton and Ce3+-luminescences in pure and doped LiBaF3 crystals were determined on the basis of analysis of the time resolved emission and excitation spectra. It is shown that excitation of Ce-luminescence is caused both by carriers capture at or near activator ions and b
ESSenCe 2011 GLORIA Measurements
Guggenmoser, T.
2012-04-01
The ESA Sounder Campaign (ESSenCe) was conducted in November and December of 2011 in Kiruna (Swedish Lapland). Its main focus has been on observation of the UT/LS region using the new Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA), an infrared remote sensing instrument developed jointly by Forschungszentrum Jülich (FZJ) and Karlsruher Institut für Technologie (KIT). Arena Arctica served as the campaign's base of operations and the Myasishchev Design Bureau's M-55 Geophysica high-altitude research aircraft as the instrument carrier. GLORIA, the successor to the MIPAS and CRISTA instruments, is a limb-sounding Fourier transform spectrometer that can capture several thousand interferograms at once on a two-dimensional detector array. The instrument is mounted on a frame that provides high-precision attitude control and stabilization. GLORIA is designed to run in either of two operation modes, emphasizing spatial (Dynamics Mode) or spectral resolution (Chemistry Mode) as desired. The chemistry mode makes the retrieval of profiles for a multitude of trace species feasible while dynamics mode data is optimized for resolving spatial structures like tropospheric intrusions and gravity (bouyancy) waves. Studies performed at FZJ have shown that, given the right conditions, dynamics mode measurements can serve as the input for 3-dimensional tomographic retrievals. GLORIA data processing is performed jointly by FZJ (IEK-7) and KIT (IMK-ASF), where the focus is on the dynamics mode and the chemistry mode, respectively. During the ESSenCe campaign, two flights were performed on December 11th and 16th. GLORIA provided measurements during both flights and the data is as of now being processed and evaluated. This presentation aims to give an overview of GLORIA campaign operations as well as the status of the ongoing data analysis, with an outlook on future activities.
Anderson's absolute objects and constant timelike vector hidden in Dirac matrices
2001-01-01
Anderson's theorem asserting, that symmetry of dynamic equations written in the relativisitically covariant form is determined by symmetry of its absolute objects, is applied to the free Dirac equation. Dirac matrices are the only absolute objects of the Dirac equation. There are two ways of the Dirac matrices transformation: (1) Dirac matrices form a 4-vector and wave function is a scalar, (2) Dirac matrices are scalars and the wave function is a spinor. In the first case the Dirac equation ...
Notes on the Norm Estimates for the Sum of Two Matrices
Institute of Scientific and Technical Information of China (English)
Man Duen CHOI
2003-01-01
This is a lecture note of my joint work with Chi-Kwong Li concerning various results on thenorm structure of n x n matrices (as Hilbert-space operators). The main result says that the triangleinequality serves as the ultimate norm estimate for the upper bounds of summation of two matrices.In the case of summation of two normal matrices, the result turns out to be a norm estimate in termsof the spectral variation for normal matrices.