Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
axes must be taken into account for accurate interpretation of XMLD data. Magnetism and X Rays The ancient Greeks and also the Chinese knew about strange and rare...
Jaenkaelae, K. [Department of Physics, P.O. Box 3000, 90014 University of Oulu, Oulu (Finland); Alagia, M. [CNR-IOM, Laboratorio TASC, IT-34149 Trieste (Italy); Feyer, V.; Richter, R. [Sincrotrone Trieste, Area Science Park, IT-34149 Trieste (Italy); Prince, K. C. [Sincrotrone Trieste, Area Science Park, IT-34149 Trieste (Italy); CNR-IOM, Laboratorio TASC, IT-34149 Trieste (Italy)
2011-11-15T23:59:59.000Z
Laser orientation in the initial state has been used to study the properties of satellite transitions in inner-shell photoionization of rubidium atoms. The linear magnetic dichroism in the angular distribution (LMDAD) has been utilized to probe the continuum waves of orbital angular momentum conserving monopole, and angular momentum changing conjugate satellites, accompanying the 4p ionization of atomic Rb. We show experimentally that LMDAD of both types of satellite transitions is nonzero and that LMDAD of monopole satellites, measured as a function of photon energy, mimics the LMDAD of direct photoionization, whereas the LMDAD of conjugate transitions deviates drastically from that trend. The results indicate that conjugate transitions cannot be described theoretically without explicit inclusion of electron-electron interaction. The present data can thus be used as a very precise test of current models for photoionization.
Goodman, K.W.; Tobin, J.G.; Schumann, F.O. [Pennsylvania State Univ., University Park, PA (United States); Willis, R.F. [Pennsylvania State Univ., University Park, PA (United States); Gammon, J.W. [Virginia Commonwealth Univ., Richmond, VA (United States); Pappas, D.P. [Virginia Commonwealth Univ., Richmond, VA (United States); Kortright, J.B. [Lawrence Berkeley National Lab., CA (United States); Denlinger, J.D. [Lawrence Berkeley National Lab., CA (United States); Rotenberg, E. [Lawrence Berkeley National Lab., CA (United States); Warwick, A. [Lawrence Berkeley National Lab., CA (United States); Smith, N.V. [Lawrence Berkeley National Lab., CA (United States)
1997-03-26T23:59:59.000Z
We have observed circular and linear magnetic dichroism in angle- resolved photoemission spectra of 50-monolayer Gd film grown on Y(0001) and 6-monolayer Fe-Ni alloy films grown on Cu(001). The 4f level of Gd and the Fe 3p level of the Fe-Ni alloy were measured. A different geometry was used for the magnetic circular dichroism than was used to measure the magnetic linear dichroism. The geometries were chosen so that the shape of the magnetic circular dichroism is predicted to be equal to the shape of the magnetic linear dichroism for four-fold symmetric Fe-Ni/Cu(001) but not for three-fold symmetric Gd/Y(0001). Experimental results are presented. In this paper we examine the effect of symmetry (experimental geometry and sample geometry) on magnetic linear and circular dichroism in angle- resolved photoemission. In particular we chose separate geometries for measuring magnetic circular and magnetic linear dichroism. The geometries were chosen such that samples with four-fold symmetry about the sample normal may have magnetic circular and magnetic linear dichroism of the same shape. But samples with three-fold symmetry should not exhibit circular and magnetic linear dichroism of the same shape. The samples studied are three-fold symmetric Gd films grown on Y(0001) and four-fold symmetric Fe-Ni alloy grown on Cu(001). After presenting the methods of the experiment, we briefly review parts of a model of magnetic dichroism developed by Venus and coworkers and our specialization and extension of it, particularly for FeNi/Cu(001). We then show the results of our measurements.
V. Socoliuc; L. B. Popescu
2014-10-09T23:59:59.000Z
An analytical theoretical model for the influence of the magnetically induced nanoparticle chaining on the linear dichroism in ferrofluids was developed. The model is based on a statistical theory for magnetic nanoparticle chaining in ferrofluids. Together with appropriate experimental approach and data processing strategy, the model grounds a magneto-optical granulometry method able to determine the magnetic field dependence of the statistics of magnetically induced particle chains in concentrated ferrofluids.
Properties of thin film europium oxide by x-ray magnetic circular dichroism Johnathon Holroyda)
Idzerda, Yves
Properties of thin film europium oxide by x-ray magnetic circular dichroism Johnathon Holroyda Institute of Physics. DOI: 10.1063/1.1688653 I. INTRODUCTION Europium oxide is optically transparent
Rehault, Julien; Helbing, Jan [Physikalisch-Chemisches Institut, Universitaet Zuerich, Winterthurerstrasse 190, 8057 Zuerich (Switzerland); Zanirato, Vinicio [Dipartimento di Scienze Farmaceutiche, Universita di Ferrara, via Fossato di Mortara 17-19, I-44100 Ferrara (Italy); Olivucci, Massimo [Dipartimento di Chimica, Universita di Siena, via Aldo Moro 2, I-53100 Siena (Italy) and Chemistry Department, Bowling Green State University, Bowling Green, Ohio 43403 (United States)
2011-03-28T23:59:59.000Z
We demonstrate strong amplification of polarization-sensitive transient IR signals using a pseudo-null crossed polarizer technique first proposed by Keston and Lospalluto [Fed. Proc. 10, 207 (1951)] and applied for nanosecond flash photolysis in the visible by Che et al. [Chem. Phys. Lett. 224, 145 (1994)]. We adapted the technique to ultrafast pulsed laser spectroscopy in the infrared using photoelastic modulators, which allow us to measure amplified linear dichroism at kilohertz repetition rates. The method was applied to a photoswitch of the N-alkylated Schiff base family in order to demonstrate its potential of strongly enhancing sensitivity and signal to noise in ultrafast transient IR experiments, to simplify spectra and to determine intramolecular transition dipole orientations.
Arbelaez, D.; Black, A.; Prestemon, S.O.; Wang, S.; Chen, J.; Arenholz, E.
2010-01-13T23:59:59.000Z
An eight-pole superconducting magnet is being developed for soft x-ray magnetic dichroism (XMD) experiments at the Advanced Light Source, Lawrence Berkley National Laboratory (LBNL). Eight conical Nb{sub 3}Sn coils with Holmium poles are arranged in octahedral symmetry to form four dipole pairs that provide magnetic fields of up to 5 T in any direction relative to the incoming x-ray beam. The dimensions of the magnet yoke as well as pole taper, diameter, and length were optimized for maximum peak field in the magnet center using the software package TOSCA. The structural analysis of the magnet is performed using ANSYS with the coil properties derived using a numerical homogenization scheme. It is found that the use of orthotropic material properties for the coil has an important influence in the design of the magnet.
Spin polarization and magnetic dichroism in core-level photoemission from ferromagnets
Menchero, J G [Univ. of California, Berkeley, CA (United States). Dept. of Physics
1997-05-01T23:59:59.000Z
In this thesis we present a theoretical investigation of angle- and spin-resolved core-level photoemission from ferromagnetic Fe and Ni. We also consider magneto-dichroic effects due to reversal of the photon helicity or reversal of the sample magnetization direction. In chapter 1, we provide a brief outline of the history of photoemission, and show how it has played an important role in the development of modern physics. We then review the basic elements of the theory of core-level photoemission, and discuss the validity of the some of the commonly-used approximations. In chapter 2, we present a one-electron theory to calculate spin- and angle-resolved photoemission spectra for an arbitrary photon polarization. The Hamiltonian includes both spin-orbit and exchange interactions. As test cases for the theory, we calculate the spin polarization and magnetic dichroism for the Fe 2p core level, and find that agreement with experiment is very good.
Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron Spin TransitionProgramUndergraduate
Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron Spin TransitionProgramUndergraduateUnexpected Angular Dependence of
Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron Spin TransitionProgramUndergraduateUnexpected Angular Dependence
Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron Spin TransitionProgramUndergraduateUnexpected Angular
Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over OurThe Iron Spin TransitionProgramUndergraduateUnexpected AngularUnexpected Angular
Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del SolStrengthening aTurbulence mayUndergraduate ProgramCenter |Solar wind
Infrared dichroism of gold nanorods controlled using a magnetically addressable mesophase
Kostyantyn Slyusarenko; Doru Constantin; Benjamin Abécassis; Patrick Davidson; Corinne Chaéac
2014-06-16T23:59:59.000Z
Gold nanorods have unique optical properties, which make them promising candidates for building nano-structured materials using a "bottom-up" strategy. We formulate stable bulk materials with anisotropic optical properties by inserting gold and iron oxide nanorods within a lamellar mesophase. Quantitative measurements of the order parameter by modelling the absorbance spectra show that the medium is macroscopically aligned in a direction defined by an external magnetic field. Under field, the system exhibits significant absorption dichroism in the infrared range, at the position of the longitudinal plasmon peak of the gold nanorods (about 1200 nm), indicating strong confinement of these particles within the water layers of the lamellar phase. This approach can yield soft and addressable optical elements.
Atomic moments in Mn2CoAl thin films analyzed by X-ray magnetic circular dichroism
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Jamer, M. [Northwestern Univ., Evanston, IL (United States). Dept. of Physics; Sterbinsky, G. [Brookhaven National Laboratory (BNL), Upton, NY (United States). Photon Sciences Directorate; Assaf, B. [Northwestern Univ., Evanston, IL (United States). Dept. of Physics; Arena, D. [Brookhaven National Laboratory (BNL), Upton, NY (United States). Photon Sciences Directorate; Heiman, D. [Northwestern Univ., Evanston, IL (United States). Dept. of Physics
2014-12-07T23:59:59.000Z
Spin gapless semiconductors are known to be strongly affected by structural disorder when grown epitaxially as thin films. The magnetic properties of Mn2CoAl thin films grown on GaAs (001) substrates are investigated here as a function of annealing. This study investigates the atomic-specific magnetic moments of Mn and Co atoms measured through X-ray magnetic circular dichroism as a function of annealing and the consequent structural ordering. The results indicate that the structural distortion mainly affects the Mn atoms as seen by the reduction of the magnetic moment from its predicted value. (auth)
Wilson, Daniel; Rudolf, Denis, E-mail: d.rudolf@fz-juelich.de; Juschkin, Larissa [RWTH Aachen University, Experimental Physics of EUV, Steinbachstraße 15, 52074 Aachen (Germany); Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI-9), JARA-FIT, 52425 Jülich (Germany); Weier, Christian; Adam, Roman; Schneider, Claus M. [Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI-6), JARA-FIT, 52425 Jülich (Germany); Winkler, Gerrit; Frömter, Robert [Institut für Angewandte Physik, Universität Hamburg, Jungiusstraße 11, 20355 Hamburg (Germany); Danylyuk, Serhiy [RWTH Aachen University, Chair for Technology of Optical Systems, JARA-FIT, Steinbachstraße 15, 52074 Aachen (Germany); Bergmann, Klaus [Fraunhofer Institute for Laser Technology, Steinbachstrasse 15, 52074 Aachen (Germany); Grützmacher, Detlev [Forschungszentrum Jülich GmbH, Peter Grünberg Institut (PGI-9), JARA-FIT, 52425 Jülich (Germany)
2014-10-15T23:59:59.000Z
Generation of circularly polarized light in the extreme ultraviolet (EUV) spectral region (about 25 eV–250 eV) is highly desirable for applications in spectroscopy and microscopy but very challenging to achieve in a small-scale laboratory. We present a compact apparatus for generation of linearly and circularly polarized EUV radiation from a gas-discharge plasma light source between 50 eV and 70 eV photon energy. In this spectral range, the 3p absorption edges of Fe (54 eV), Co (60 eV), and Ni (67 eV) offer a high magnetic contrast often employed for magneto-optical and electron spectroscopy as well as for magnetic imaging. We simulated and designed an instrument for generation of linearly and circularly polarized EUV radiation and performed polarimetric measurements of the degree of linear and circular polarization. Furthermore, we demonstrate first measurements of the X-ray magnetic circular dichroism at the Co 3p absorption edge with a plasma-based EUV light source. Our approach opens the door for laboratory-based, element-selective spectroscopy of magnetic materials and spectro-microscopy of ferromagnetic domains.
Nuclear spin circular dichroism
Vaara, Juha, E-mail: juha.vaara@iki.fi [NMR Research Group, Department of Physics, University of Oulu, P.O. Box 3000, FIN-90014 Oulu (Finland)] [NMR Research Group, Department of Physics, University of Oulu, P.O. Box 3000, FIN-90014 Oulu (Finland); Rizzo, Antonio [Istituto per i Processi Chimico-Fisici del Consiglio Nazionale delle Ricerche (IPCF-CNR), Area della Ricerca, via G. Moruzzi 1, I-56124 Pisa (Italy)] [Istituto per i Processi Chimico-Fisici del Consiglio Nazionale delle Ricerche (IPCF-CNR), Area della Ricerca, via G. Moruzzi 1, I-56124 Pisa (Italy); Kauczor, Joanna; Norman, Patrick [Department of Physics, Chemistry and Biology, Linköping University, S-58183 Linköping (Sweden)] [Department of Physics, Chemistry and Biology, Linköping University, S-58183 Linköping (Sweden); Coriani, Sonia, E-mail: coriani@units.it [Dipartimento di Scienze Chimiche e Farmaceutiche, Università degli Studi di Trieste, Via L. Giorgieri 1, I-34127 Trieste (Italy)] [Dipartimento di Scienze Chimiche e Farmaceutiche, Università degli Studi di Trieste, Via L. Giorgieri 1, I-34127 Trieste (Italy)
2014-04-07T23:59:59.000Z
Recent years have witnessed a growing interest in magneto-optic spectroscopy techniques that use nuclear magnetization as the source of the magnetic field. Here we present a formulation of magnetic circular dichroism (CD) due to magnetically polarized nuclei, nuclear spin-induced CD (NSCD), in molecules. The NSCD ellipticity and nuclear spin-induced optical rotation (NSOR) angle correspond to the real and imaginary parts, respectively, of (complex) quadratic response functions involving the dynamic second-order interaction of the electron system with the linearly polarized light beam, as well as the static magnetic hyperfine interaction. Using the complex polarization propagator framework, NSCD and NSOR signals are obtained at frequencies in the vicinity of optical excitations. Hartree-Fock and density-functional theory calculations on relatively small model systems, ethene, benzene, and 1,4-benzoquinone, demonstrate the feasibility of the method for obtaining relatively strong nuclear spin-induced ellipticity and optical rotation signals. Comparison of the proton and carbon-13 signals of ethanol reveals that these resonant phenomena facilitate chemical resolution between non-equivalent nuclei in magneto-optic spectra.
Lee, Yongbin; Kim, Jong-Woo; Goldman, Alan I.; Harmon, Bruce N. (Iowa State)
2010-07-19T23:59:59.000Z
In this study we have used first principles electronic structure methods to investigate the detailed contributions to the L{sub 3}/L{sub 2} branching ratio in the heavy rare earth elements. The calculations use the full potential, relativistic, linear augmented plane wave method with the LSDA+U approach for consideration of the local 4f electronic orbitals. With no spin orbit coupling (SOC) in the conducting bands, and with the same radial function for the 2p{sub 3/2} and 2p{sub 1/2} core states, the branching ratio (BR) is exactly 1:-1 for the x-ray magnetic circular dichroism spectra of the ferromagnetic heavy rare earth metals. However, with full SOC the BR ranges from 1.5 to 6.0 in going from Gd to Er. The energy and spin dependence of the 5d radial functions are important. The results point to problems with modified atomic models which have been proposed to explain the BR. Recent x-ray resonant magentic scattering experiments on (Gd,Tb,Dy,Ho,Er,Tm)Ni{sub 2}Ge{sub 2} are discussed.
Ito, Keita; Sanai, Tatsunori; Yasutomi, Yoko; Toko, Kaoru; Suemasu, Takashi, E-mail: suemasu@bk.tsukuba.ac.jp [Institute of Applied Physics, Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Zhu, Siyuan; Kimura, Akio [Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Takeda, Yukiharu; Saitoh, Yuji [Condensed Matter Science Division, Japan Atomic Energy Agency, 1-1-1 Kouto, Sayo-cho, Hyogo 679-5148 (Japan)
2014-05-07T23:59:59.000Z
We evaluated orbital (m{sub orb}) and spin magnetic moments (m{sub spin}) of Co{sub x}Fe{sub 4?x}N (x?=?0, 3, 4) epitaxial thin films grown by molecular beam epitaxy using x-ray magnetic circular dichroism, and discussed the dependence of these values on x. Site-averaged m{sub spin} value of Fe atoms was deduced to be 1.91??{sub B} per atom, and that of Co atoms to be 1.47??{sub B} per atom in Co{sub 3}FeN at 300?K. These values are close to 1.87??{sub B} per Fe atom in Fe{sub 4}N and 1.43??{sub B} per Co atom in Co{sub 4}N, respectively. This result implies that the Fe and Co atoms in the Co{sub 3}FeN films were located both at corner and face-centered sites in the anti-perovskite lattice. Spin magnetic moments per unit cell were decreased linearly with increasing x in Co{sub x}Fe{sub 4?x}N. This tendency is in good agreement with theory predicted by the first-principle calculation.
Atomic moments in Mn_{2}CoAl thin films analyzed by X-ray magnetic circular dichroism
Jamer, M. [Northwestern Univ., Evanston, IL (United States). Dept. of Physics; Sterbinsky, G. [Brookhaven National Laboratory (BNL), Upton, NY (United States). Photon Sciences Directorate; Assaf, B. [Northwestern Univ., Evanston, IL (United States). Dept. of Physics; Arena, D. [Brookhaven National Laboratory (BNL), Upton, NY (United States). Photon Sciences Directorate; Heiman, D. [Northwestern Univ., Evanston, IL (United States). Dept. of Physics
2014-12-07T23:59:59.000Z
Spin gapless semiconductors are known to be strongly affected by structural disorder when grown epitaxially as thin films. The magnetic properties of Mn_{2}CoAl thin films grown on GaAs (001) substrates are investigated here as a function of annealing. This study investigates the atomic-specific magnetic moments of Mn and Co atoms measured through X-ray magnetic circular dichroism as a function of annealing and the consequent structural ordering. The results indicate that the structural distortion mainly affects the Mn atoms as seen by the reduction of the magnetic moment from its predicted value. (auth)
van der Laan, G.; Edmonds, K. W.; Arenholz, E.; Farley, N. R. S.; Gallagher, B. L.
2010-03-30T23:59:59.000Z
We present a valence-state model to explain the characteristics of a recently observed pre-edge feature in Mn L{sub 3} x-ray magnetic circular dichroism (XMCD) of ferromagnetic (Ga,Mn)As and (Al,Ga,Mn)As thin films. The prepeak XMCD shows a uniaxial anisotropy, contrary to the cubic symmetry of the main structures induced by the crystalline electric field. Reversing the strain in the host lattice reverses the sign of the uniaxial anisotropy. With increasing carrier localization, the prepeak height increases, indicating an increasing 3d character of the hybridized holes. Hence, the feature is ascribed to transitions from the Mn 2p core level to unoccupied p-d hybridized valence states. The characteristics of the prepeak are readily reproduced by the model calculation taking into account the symmetry of the strain-, spin-orbit-, and exchange-split valence states around the zone center.
Mn l3,2 x-ray absorption spectroscopy and magnetic circular dichroism in ferromagnetic ga1-xmnxp
2008-01-01T23:59:59.000Z
pulsed-laser melting (II-PLM) [2]. Unlike the holes in thethe magnetic properties of II-PLM films are dominated by the
Magnetic levitation configuration incorporating levitation, guidance and linear synchronous motor
Coffey, H.T.
1993-10-19T23:59:59.000Z
A propulsion and suspension system for an inductive repulsion type magnetically levitated vehicle which is propelled and suspended by a system which includes propulsion windings which form a linear synchronous motor and conductive guideways, adjacent to the propulsion windings, where both combine to partially encircling the vehicle-borne superconducting magnets. A three phase power source is used with the linear synchronous motor to produce a traveling magnetic wave which in conjunction with the magnets propel the vehicle. The conductive guideway combines with the superconducting magnets to provide for vehicle levitation. 3 figures.
Magnetic levitation configuration incorporating levitation, guidance and linear synchronous motor
Coffey, Howard T. (Darien, IL)
1993-01-01T23:59:59.000Z
A propulsion and suspension system for an inductive repulsion type magnetically levitated vehicle which is propelled and suspended by a system which includes propulsion windings which form a linear synchronous motor and conductive guideways, adjacent to the propulsion windings, where both combine to partially encircling the vehicle-borne superconducting magnets. A three phase power source is used with the linear synchronous motor to produce a traveling magnetic wave which in conjunction with the magnets propel the vehicle. The conductive guideway combines with the superconducting magnets to provide for vehicle leviation.
Haskel, Daniel
- tention due to their potential for use in magnetic refrigeration.17 Among these materials, Gd5 SixGe1-x 4 transition,4,6 making them attractive candidates for magnetic refrigeration near room temperatureEffect of hydrostatic pressure upon the magnetic transitions in the Gd5,,SixGe1-x...4 giant
Novel Approach to Linear Accelerator Superconducting Magnet System
Kashikhin, Vladimir; /Fermilab
2011-11-28T23:59:59.000Z
Superconducting Linear Accelerators include a superconducting magnet system for particle beam transportation that provides the beam focusing and steering. This system consists of a large number of quadrupole magnets and dipole correctors mounted inside or between cryomodules with SCRF cavities. Each magnet has current leads and powered from its own power supply. The paper proposes a novel approach to magnet powering based on using superconducting persistent current switches. A group of magnets is powered from the same power supply through the common, for the group of cryomodules, electrical bus and pair of current leads. Superconducting switches direct the current to the chosen magnet and close the circuit providing the magnet operation in a persistent current mode. Two persistent current switches were fabricated and tested. In the paper also presented the results of magnetic field simulations, decay time constants analysis, and a way of improving quadrupole magnetic center stability. Such approach substantially reduces the magnet system cost and increases the reliability.
Optimization of a dual acting, magnetically driven, linear actuator
Willerton, Justin Ryan
2002-01-01T23:59:59.000Z
In this study the geometry of a dual acting, magnetically driven, linear motion actuator will be optimized. This will be accomplished by modeling the system through a set of differential equations to be solved in Matlab. ...
Cryogen free superconducting splittable quadrupole magnet for linear accelerators
Kashikhin, V.S.; Andreev, N.; Kerby, J.; Orlov, Y.; Solyak, N.; Tartaglia, M.; Velev, G.; /Fermilab
2011-09-01T23:59:59.000Z
A new superconducting quadrupole magnet for linear accelerators was fabricated at Fermilab. The magnet is designed to work inside a cryomodule in the space between SCRF cavities. SCRF cavities must be installed inside a very clean room adding issues to the magnet design, and fabrication. The designed magnet has a splittable along the vertical plane configuration and could be installed outside of the clean room around the beam pipe previously connected to neighboring cavities. For more convenient assembly and replacement a 'superferric' magnet configuration with four racetrack type coils was chosen. The magnet does not have a helium vessel and is conductively cooled from the cryomodule LHe supply pipe and a helium gas return pipe. The quadrupole generates 36 T integrated magnetic field gradient, has 600 mm effective length, and the peak gradient is 54 T/m. In this paper the quadrupole magnetic, mechanical, and thermal designs are presented, along with the magnet fabrication overview and first test results.
Zero-Field Dichroism in the Solar Chromosphere
R. Manso Sainz; J. Trujillo Bueno
2003-11-19T23:59:59.000Z
We explain the linear polarization of the Ca II infrared triplet observed close to the edge of the solar disk. In particular, we demonstrate that the physical origin of the enigmatic polarizations of the 866.2 nm and 854.2 nm lines lies in the existence of atomic polarization in their metastable lower levels, which produces differential absorption of polarization components (dichroism). To this end, we have solved the problem of the generation and transfer of polarized radiation by taking fully into account all the relevant optical pumping mechanisms in multilevel atomic models. We argue that `zero-field' dichroism may be of great diagnostic value in astrophysics.
Mn L3,2 X-ray absorption and magnetic circular dichroism in ferromagnetic Ga1-xMnxP
2006-01-01T23:59:59.000Z
and pulsed-laser melting (II-PLM) [2-4]. At 0.4 eV above thex P were synthesized by II-PLM [10]. GaP (001) wafers dopedthis material formed by II-PLM have shown that its magnetic
13th International Conference on Magnetically Levitated Systems and Linear Drives
Not Available
1993-09-01T23:59:59.000Z
This report contains short papers on research being conducted throughout the world on magnetically levitated systems, mainly consisting of trains, and magnetic linear drives. These papers have been index separately elsewhere on the data base.
Linear metric and temperature fluctuations of a charged plasma in a primordial magnetic field
Haba, Z
2015-01-01T23:59:59.000Z
We discuss tensor metric perturbations in a magnetic field around the homogeneous Juttner equilibrium of massless particles in an expanding universe. We solve the Liouville equation and derive the energy-momentum tensor up to linear terms in the metric and in the magnetic field.The term linear in the magnetic field is different from zero if the total charge of the primordial plasma is non-zero. We obtain an analytic formula for temperature fluctuations treating the tensor metric perturbations and the magnetic field as independent random variables. Assuming a cutoff on large momenta of the magnetic spectral function we show that the presence of the magnetic field can discriminate only low multipoles in the multipole expansion of temperature fluctuations. In such a case the term linear in the magnetic field can be more important than the quadratic one (corresponding to the fluctuations of the pure magnetic field).
Yao, Bin
magnet synchronous motor (PMSM) offers several advantages of high transmission efficiency and high cylinder driven by permanent magnet synchronous motor (PMSM). Though direct-drive linear motors has some to direct-drive linear motor, the solution of electrical cylinder with PMSM has larger output force
Magnetic Dichroism Spectromicroscopy at SPEAR3
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9November 6, InaprilU . SMagellan Reportray
Superconducting magnets for SCRF cryomodules at front end of linear accelerators
Kashikhin, V.S.; Andreev, N.; Orlov, Y.; Orris, D.F.; Tartaglia, M.A.; /Fermilab
2010-05-01T23:59:59.000Z
Linear accelerators based on a superconducting technology need various superconducting magnets mounted inside SCRF Cryomodules. Relatively weak iron-dominated magnets are installed at the front end of linear accelerators. The focusing quadrupoles have integrated gradients in the range of 1-4 T, and apertures in the range 35-90 mm. Superconducting dipole correctors and quadrupoles were designed at Fermilab for various projects. In this paper these magnet designs, and test results of a fabricated dipole corrector, are presented. Also briefly discussed are magnetic and mechanical designs, quench protection, cooling, fabrication, and assembly into cryomodule.
ACTIVE SUSPENSION CONTROL WITH DIRECT-DRIVE TUBULAR LINEAR BRUSHLESS PERMANENT-MAGNET MOTOR
Lee, Seungho
2010-01-16T23:59:59.000Z
Recently, active suspension has been applied to many commercial automobiles. To develop the control algorithm for active suspension, a quarter-car test bed was built by using a direct-drive tubular linear brushless permanent-magnet motor (LBPMM...
5-loop Konishi from linearized TBA and the XXX magnet
Janos Balog; Arpad Hegedus
2010-06-08T23:59:59.000Z
Using the linearized TBA equations recently obtained in [arXiv:1002.1711] we show analytically that the 5-loop anomalous dimension of the Konishi operator agrees with the result obtained previously from the generalized Luscher formulae. The proof is based on the relation between this linear system and the XXX model TBA equations.
Improvement of the magnetic core for eddy current losses decreasing in cylindrical linear actuators.
Boyer, Edmond
Improvement of the magnetic core for eddy current losses decreasing in cylindrical linear actuators the power) increases, the iron losses become high [1]. One classical method for reducing the eddy current the eddy current losses in a longitudinal flux multi-rod actuator and to compute improvement. 2 The linear
A linear helicon plasma device with controllable magnetic field gradient
Barada, Kshitish K.; Chattopadhyay, P. K.; Ghosh, J.; Kumar, Sunil; Saxena, Y. C. [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat 382428 (India)
2012-06-15T23:59:59.000Z
Current free double layers (CFDLs) are localized potential structures having spatial dimensions - Debye lengths and potential drops of more than local electron temperature across them. CFDLs do not need a current for them to be sustained and hence they differ from the current driven double layers. Helicon antenna produced plasmas in an expanded chamber along with an expanding magnetic field have shown the existence of CFDL near the expansion region. A helicon plasma device has been designed, fabricated, and installed in the Institute for Plasma Research, India to study the role of maximum magnetic field gradient as well as its location with respect to the geometrical expansion region of the chamber in CFDL formation. The special feature of this machine consisting of two chambers of different radii is its capability of producing different magnetic field gradients near the physical boundary between the two chambers either by changing current in one particular coil in the direction opposite to that in other coils and/or by varying the position of this particular coil. Although, the machine is primarily designed for CFDL experiments, it is also capable of carrying out many basic plasma physics experiments such as wave propagation, wave coupling, and plasma instabilities in a varying magnetic field topology. In this paper, we will present the details of the machine construction, its specialties, and some preliminary results about the production and characterization of helicon plasma in this machine.
Oldest Known Magnet's Secrets Revealed Under High Pressures ...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
dichroism technique is readily applied to most magnetic materials without the need for isotope enrichment, and provides a true measure of long-range magnetic order." Other...
Calculation of cogging force in a novel slotted linear tubular brushless permanent magnet motor
Zhu, Z.Q.; Hor, P.J.; Howe, D. [Univ. of Sheffield (United Kingdom). Dept. of Electronic and Electrical Engineering] [Univ. of Sheffield (United Kingdom). Dept. of Electronic and Electrical Engineering; Rees-Jones, J. [Unilever Research Port Sunlight Lab., Bebington (United Kingdom)] [Unilever Research Port Sunlight Lab., Bebington (United Kingdom)
1997-09-01T23:59:59.000Z
There is an increasing requirement for controlled linear motion over short and long strokes, in the factory automation and packaging industries, for example. Linear brushless PM motors could offer significant advantages over conventional actuation technologies, such as motor driven cams and linkages and pneumatic rams--in terms of efficiency, operating bandwidth, speed and thrust control, stroke and positional accuracy, and indeed over other linear motor technologies, such as induction motors. Here, a finite element/analytical based technique for the prediction of cogging force in a novel topology of slotted linear brushless permanent magnet motor has been developed and validated. The various force components, which influence cogging are pre-calculated by the finite element analysis of some basic magnetic structures, facilitate the analytical synthesis of the resultant cogging force. The technique can be used to aid design for the minimization of cogging.
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
for magnetic circular dichroism (XMCD) and magnetic scattering experiments. Sunset Yellow 6-ID-B: Resonant and In-Field Scattering Beamline 6-ID-B,C is the primary beamline on...
Linear theory for fast collisionless magnetic reconnection in the lower-hybrid frequency range
Jovanovic, D.; Shukla, P.K. [Institute of Physics, P.O. Box 57, 11001 Belgrade (Serbia and Montenegro); Institut fuer Theoretische Physik IV and Centre for Plasma Science and Astrophysik, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)
2005-05-15T23:59:59.000Z
A linear theory is presented for the interplay between the fast collisionless magnetic reconnection and the lower-hybrid waves that has been observed in recent computer simulations [J. F. Drake, M. Swisdak, C. Cattell et al., Science 299, 873 (2003)]. In plasma configurations with a strong guide field and anisotropic electron temperature, the electron dynamics is described within the framework of standard electron magnetohydrodynamic equations, accounting also for the effects of the electron polarization and ion motions in the presence of perpendicular electric fields. In the linear phase, we find two types of instabilities of a thin current sheet with steep edges, corresponding to its filamentation (or tearing) and bending. Using a surface-wave formalism for the perturbations whose wavelength is larger than the thickness of the current sheet, the corresponding growth rates are calculated as the contributions of singularities in the plasma dispersion function. These are governed by the electron inertia and the linear coupling of the reconnecting magnetic field with local plasma modes propagating in the perpendicular direction that are subject to the Buneman instability. The linear surface wave instability may be particularly important as a secondary instability, dissipating the thin current sheets that develop in the course of the fast reconnection in the shear-Alfven and kinetic-Alfven regimes, and providing the anomalous resistivity for the growth of magnetic islands beyond the shear-Alfven and kinetic-Alfven scales.
Linear beam raster magnet driver based on H-bridge technique
Sinkine, Nikolai I.; Yan, Chen; Apeldoorn, Cornelis; Dail, Jeffrey Glenn; Wojcik, Randolph Frank; Gunning, William
2006-06-06T23:59:59.000Z
An improved raster magnet driver for a linear particle beam is based on an H-bridge technique. Four branches of power HEXFETs form a two-by-two switch. Switching the HEXFETs in a predetermined order and at the right frequency produces a triangular current waveform. An H-bridge controller controls switching sequence and timing. The magnetic field of the coil follows the shape of the waveform and thus steers the beam using a triangular rather than a sinusoidal waveform. The system produces a raster pattern having a highly uniform raster density distribution, eliminates target heating from non-uniform raster density distributions, and produces higher levels of beam current.
Sunandan Gangopadhyay; Anirban Saha
2012-04-02T23:59:59.000Z
We consider the dynamics of a charged particle interacting with background electromagnetic field under the influence of linearized gravitational waves in the long wave-length and low-velocity limit. Following the prescription in \\cite{speli}, the system is quantized and the Hamiltonian is then solved by using standard algebraic iterative methods. The solution is in conformity with the classical analysis and shows the possibility of tuning the frequency by changing the magnetic field to set up resonance.
Study of plasma dynamics affected by a global magnetic field in linear wire array Z pinches
Hu Min; Kusse, Bruce R. [Laboratory of Plasma Studies, Cornell University, Ithaca, New York 14853 (United States)
2005-10-01T23:59:59.000Z
In the experiments described in this paper a linear wire array composed of several wires (e.g., four wires) was viewed as a small portion of a large cylindrical array. Comparing to cylindrical arrays, linear wire arrays have relatively simple geometry and therefore are much easier to diagnose. To simulate the global magnetic field present in a cylindrical array, a return current conductor was positioned near the linear wire array. A global magnetic field in the tens of Tesla was produced by the return current in the vicinity of the linear array. The plasma dynamics affected by the global magnetic field was studied using shearing interferometry and x-ray backlighting techniques. Experimental results on tungsten wire arrays (four wires, 1.4 cm long, 12.7 {mu}m diameter, 1 mm interwire gaps) are discussed. Current transfer from wire cores to the surrounding corona plasmas appeared to happen at around 10 ns relative to the start of the current pulse. After that, some of the wire plasma was swept away from the wire cores by the JxB force and formed a localized, high-density peak (precursor plasma). The motion of the precursor plasma was observed to accelerate for about 20 ns, indicating that current was present inside the precursor plasma during this time range. Using an x-ray backlighter and a laser interferometer, the resumption of wire core expansion, major mass ablation, and the termination of precursor plasma acceleration were observed to occur at 32-34 ns. These effects can be interpreted as evidence of the transfer of the current back to the wire cores from the precursor plasma.
El-Taibany, W. F., E-mail: eltaibany@du.edu.eg, E-mail: eltaibany@hotmail.com; Selim, M. M.; Al-Abbasy, O. M. [Department of Physics, Faculty of Science, Damietta University, New Damietta P. O. 34517 (Egypt); El-Bedwehy, N. A., E-mail: nab-elbedwehy@yahoo.com [Department of Mathematics, Faculty of Science, Damietta University, New Damietta P. O. 34517 (Egypt)
2014-07-15T23:59:59.000Z
The propagation of both linear and nonlinear dust acoustic waves (DAWs) in an inhomogeneous magnetized collisional and warm dusty plasma (DP) consisting of Boltzmann ions, nonextensive electrons, and inertial dust particles is investigated. The number density gradients of all DP components besides the inhomogeneities of electrostatic potential and the initial dust fluid velocity are taken into account. The linear dispersion relation and a nonlinear modified Zakharov-Kusnetsov (MZK) equation governing the propagation of the three-dimensional DAWs are derived. The analytical solution of the MZK reveals the creation of both compressive and rarefactive DAW solitons in the proposed model. It is found that the inhomogeneity dimension parameter and the electron nonextensive parameter affect significantly the nonlinear DAW's amplitude, width, and Mach number. The relations of our findings with some astrophysical situations have been given.
Non-Linear Magnetic Ringing of Spin-Ordered Solid He-3
Hu, Chia-Ren; HAM, TE.
1981-01-01T23:59:59.000Z
PHYSICAL REVIE%' B VOLUME 24, NUMBER 5 1 SEPTEMBER 1981 Nonlinear magnetic ringing of spin-ordered solid He Chia-Ren Hu and Thomas E. Ham Departn~ent of'Physics, Texas 3 c6 M University, College Station, Texas 77843 (Received 24 October 1980... derivative of d. If Eqs; (2) and (3) are first linearized around the equilibrium solution for / H =cosH (where H ?= H/H), viz. , yS =yaH, d l = d S =0, and l S =cosH, the resulting equa- tions then describe the undamped resonance modes of frequencies...
Beam-turning magnet design and test for the Recirculating Linear Accelerator
Crow, J.T. (Sandia National Labs., Albuquerque, NM (United States)); Platt, R.C. (Science Applications International Corp., San Diego, CA (United States))
1991-01-01T23:59:59.000Z
We have designed and tested a system for applying a ramped vertical magnetic field for turning the electron beam in the IFR Recirculating Linear Accelerator. The field is highly uniform over two Gaussian beam radii, and can be adjusted for a large radial gradient for increased energy bandwidth. The system includes shielding of the current-carrying rods to protect the pulser from REB induced fields and to reduce the effect of REB images on the beam transport to negligible levels. The system has been tested on the IBEX accelerator with > 95% peak current transport and > 90% charge transport through a 90{degree} turn. 2 refs., 6 figs.
Mix, C.; Finizio, S.; Jakob, G.; Kläui, M. [Institut für Physik, Johannes Gutenberg Universität Mainz, Staudingerweg 7, D-55128 Mainz (Germany); Buzzi, M.; Nolting, F. [Swiss Light Source, Paul Scherrer Institut, CH-5232 Villigen PSI (Switzerland); Kronast, F. [Helmholtz-Zentrum-Berlin für Materialien und Energie GmbH, Albert-Einstein Straße 15, D-12489 Berlin (Germany)
2014-05-21T23:59:59.000Z
Low-thickness La{sub 0.66}Sr{sub 0.34}MnO{sub 3} (LSMO)/BiFeO{sub 3} (BFO) thin film samples deposited on SrTiO{sub 3} were imaged by high resolution x-ray microscopy at different temperatures. The ultra-thin thickness of the top layer allows to image both the ferromagnetic domain structure of LSMO and the multiferroic domain structure of the buried BFO layer, opening a path to a direct observation of coupling at the interface on a microscopic level. By comparing the domain size and structure of the BFO and LSMO, we observed that, in contrast to LSMO single layers, LSMO/BFO multilayers show a strong temperature dependence of the ferromagnetic domain structure of the LSMO. Particularly, at 40?K, a similar domain size for BFO and LSMO is observed. This indicates a persistence of exchange coupling on the microscopic scale at a temperature, where the exchange bias as determined by magnetometer measurements is vanishing.
SIMULTANEOUS MEASUREMENT OF CIRCULAR DICHROISM AND FLUORESCENCE POLARIZATION ANISOTROPY.
SUTHERLAND,J.C.
2002-01-19T23:59:59.000Z
Circular dichroism and fluorescence polarization anisotropy are important tools for characterizing biomolecular systems. Both are used extensively in kinetic experiments involving stopped- or continuous flow systems as well as titrations and steady-state spectroscopy. This paper presents the theory for determining circular dichroism and fluorescence polarization anisotropy simultaneously, thus insuring the two parameters are recorded under exactly the same conditions and at exactly the same time in kinetic experiments. The approach to measuring circular dichroism is that used in almost all conventional dichrographs. Two arrangements for measuring fluorescence polarization anisotropy are described. One uses a single fluorescence detector and signal processing with a lock-in amplifier that is similar to the measurement of circular dichroism. The second approach uses classic ''T'' format detection optics, and thus can be used with conventional photon-counting detection electronics. Simple extensions permit the simultaneous measurement of the absorption and excitation intensity corrected fluorescence intensity.
Three-dimensional linear peeling-ballooning theory in magnetic fusion devices
Weyens, T., E-mail: tweyens@fis.uc3m.es; Sánchez, R.; García, L. [Departamento de Física, Universidad Carlos III de Madrid, Madrid 28911 (Spain)] [Departamento de Física, Universidad Carlos III de Madrid, Madrid 28911 (Spain); Loarte, A.; Huijsmans, G. [ITER Organization, Route de Vinon sur Verdon, 13067 Saint Paul Lez Durance (France)] [ITER Organization, Route de Vinon sur Verdon, 13067 Saint Paul Lez Durance (France)
2014-04-15T23:59:59.000Z
Ideal magnetohydrodynamics theory is extended to fully 3D magnetic configurations to investigate the linear stability of intermediate to high n peeling-ballooning modes, with n the toroidal mode number. These are thought to be important for the behavior of edge localized modes and for the limit of the size of the pedestal that governs the high confinement H-mode. The end point of the derivation is a set of coupled second order ordinary differential equations with appropriate boundary conditions that minimize the perturbed energy and that can be solved to find the growth rate of the perturbations. This theory allows of the evaluation of 3D effects on edge plasma stability in tokamaks such as those associated with the toroidal ripple due to the finite number of toroidal field coils, the application of external 3D fields for elm control, local modification of the magnetic field in the vicinity of ferromagnetic components such as the test blanket modules in ITER, etc.
M. K. Georgoulis; Barry J. LaBonte
2007-06-27T23:59:59.000Z
We self-consistently derive the magnetic energy and relative magnetic helicity budgets of a three-dimensional linear force-free magnetic structure rooted in a lower boundary plane. For the potential magnetic energy we derive a general expression that gives results practically equivalent to those of the magnetic Virial theorem. All magnetic energy and helicity budgets are formulated in terms of surface integrals applied to the lower boundary, thus avoiding computationally intensive three-dimensional magnetic field extrapolations. We analytically and numerically connect our derivations with classical expressions for the magnetic energy and helicity, thus presenting a so-far lacking unified treatment of the energy/helicity budgets in the constant-alpha approximation. Applying our derivations to photospheric vector magnetograms of an eruptive and a noneruptive solar active regions, we find that the most profound quantitative difference between these regions lies in the estimated free magnetic energy and relative magnetic helicity budgets. If this result is verified with a large number of active regions, it will advance our understanding of solar eruptive phenomena. We also find that the constant-alpha approximation gives rise to large uncertainties in the calculation of the free magnetic energy and the relative magnetic helicity. Therefore, care must be exercised when this approximation is applied to photospheric magnetic field observations. Despite its shortcomings, the constant-alpha approximation is adopted here because this study will form the basis of a comprehensive nonlinear force-free description of the energetics and helicity in the active-region solar corona, which is our ultimate objective.
Thomas Wiegelmann; Bernd Inhester; Bernhard Kliem; Gherardo Valori; Thomas Neukirch
2006-12-21T23:59:59.000Z
CONTEXT: As the coronal magnetic field can usually not be measured directly, it has to be extrapolated from photospheric measurements into the corona. AIMS: We test the quality of a non-linear force-free coronal magnetic field extrapolation code with the help of a known analytical solution. METHODS: The non-linear force-free equations are numerically solved with the help of an optimization principle. The method minimizes an integral over the force-free and solenoidal condition. As boundary condition we use either the magnetic field components on all six sides of the computational box in Case I or only on the bottom boundary in Case II. We check the quality of the reconstruction by computing how well force-freeness and divergence-freeness are fulfilled and by comparing the numerical solution with the analytical solution. The comparison is done with magnetic field line plots and several quantitative measures, like the vector correlation, Cauchy Schwarz, normalized vector error, mean vector error and magnetic energy. RESULTS: For Case I the reconstructed magnetic field shows good agreement with the original magnetic field topology, whereas in Case II there are considerable deviations from the exact solution. This is corroborated by the quantitative measures, which are significantly better for Case I. CONCLUSIONS: Despite the strong nonlinearity of the considered force-free equilibrium, the optimization method of extrapolation is able to reconstruct it; however, the quality of reconstruction depends significantly on the consistency of the input data, which is given only if the known solution is provided also at the lateral and top boundaries, and on the presence or absence of flux concentrations near the boundaries of the magnetogram.
The First International Workshop on Synchrotron Radiation Circular Dichroism
Wallace, Bonnie Ann
The First International Workshop on Synchrotron Radiation Circular Dichroism (SRCD) Spectroscopy Sauerborn (BESSY2, Germany), Professor Alberto Spisni (LNLS, Brazil) and Dr. Zhang Guobin (NSRL, China REPORTS SYNCHROTRON RADIATION NEWS, Vol. 15, No. 1, 2002 33 1st International Workshop on SRCD
Dichroism and birefringence of natural violet diamond crystals
Konstantinova, A. F. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)], E-mail: afkonst@ns.crys.ras.ru; Titkov, S. V. [Russian Academy of Sciences, Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry (Russian Federation); Imangazieva, K. B. [Issyk Kul State University (Kyrgyzstan); Evdishchenko, E. A. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation); Sergeev, A. M. [Karpov Institute of Physical Chemistry, State Scientific Center of the Russian Federation (Russian Federation); Zudin, N. G. [OOO Roni Kerob (Russian Federation); Orekhova, V. P. [Russian Academy of Sciences, Shubnikov Institute of Crystallography (Russian Federation)
2006-05-15T23:59:59.000Z
Investigation of the optical properties of natural violet diamonds from the Yakutian kimberlites is performed. A red shift of the absorption edge is revealed in the absorption spectra of these crystals. This shift is indicative of the presence of a high concentration of nitrogen in the diamonds studied. Along with the strong band at 0.550 {mu}m, weaker bands at 0.390, 0.456 and 0.496 {mu}m are revealed. It is shown that violet diamond crystals have birefringence and dichroism of about 10{sup -5} and 10{sup -6}, respectively. When a light beam propagates perpendicularly to colored lamellas, the dichroism is much larger and the birefringence is smaller than in the case where the beam direction is parallel to lamellas.
Glenn E. Ciolek; Shantanu Basu
2006-07-27T23:59:59.000Z
We formulate the problem of the formation and collapse of nonaxisymmetric protostellar cores in weakly ionized, self-gravitating, magnetic molecular clouds. In our formulation, molecular clouds are approximated as isothermal, thin (but with finite thickness) sheets. We present the governing dynamical equations for the multifluid system of neutral gas and ions, including ambipolar diffusion, and also a self-consistent treatment of thermal pressure, gravitational, and magnetic (pressure and tension) forces. The dimensionless free parameters characterizing model clouds are discussed. The response of cloud models to linear perturbations is also examined, with particular emphasis on length and time scales for the growth of gravitational instability in magnetically subcritical and supercritical clouds. We investigate their dependence on a cloud's initial mass-to-magnetic-flux ratio (normalized to the critical value for collapse), the dimensionless initial neutral-ion collision time, and also the relative external pressure exerted on a model cloud. Among our results, we find that nearly-critical model clouds have significantly larger characteristic instability lengthscales than do more distinctly sub- or supercritical models. Another result is that the effect of a greater external pressure is to reduce the critical lengthscale for instability. Numerical simulations showing the evolution of model clouds during the linear regime of evolution are also presented, and compared to the results of the dispersion analysis. They are found to be in agreement with the dispersion results, and confirm the dependence of the characteristic length and time scales on parameters such as the initial mass-to-flux ratio and relative external pressure.
Non-linear viscoelastic response of magnetic fiber suspensions in oscillatory shear P. Kuzhira*
Paris-Sud XI, Université de
of 37 µm and diameter of 4.9 µm, dispersed in a silicon oil. Rheological measurements have been carried showed a high-frequency plateau, typical for Maxwell behavior. Our simple single relaxation time model. The magnetic fiber suspensions have shown better sedimentation stability [4
Crenshaw, Michael E., E-mail: michael.e.crenshaw4.civ@mail.mil [US Army Aviation and Missile Research, Development, and Engineering Center, Redstone Arsenal, Alabama 35898 (United States)
2014-04-15T23:59:59.000Z
In a continuum setting, the energy–momentum tensor embodies the relations between conservation of energy, conservation of linear momentum, and conservation of angular momentum. The well-defined total energy and the well-defined total momentum in a thermodynamically closed system with complete equations of motion are used to construct the total energy–momentum tensor for a stationary simple linear material with both magnetic and dielectric properties illuminated by a quasimonochromatic pulse of light through a gradient-index antireflection coating. The perplexing issues surrounding the Abraham and Minkowski momentums are bypassed by working entirely with conservation principles, the total energy, and the total momentum. We derive electromagnetic continuity equations and equations of motion for the macroscopic fields based on the material four-divergence of the traceless, symmetric total energy–momentum tensor. We identify contradictions between the macroscopic Maxwell equations and the continuum form of the conservation principles. We resolve the contradictions, which are the actual fundamental issues underlying the Abraham–Minkowski controversy, by constructing a unified version of continuum electrodynamics that is based on establishing consistency between the three-dimensional Maxwell equations for macroscopic fields, the electromagnetic continuity equations, the four-divergence of the total energy–momentum tensor, and a four-dimensional tensor formulation of electrodynamics for macroscopic fields in a simple linear medium.
Rheo-optical determination of flow birefringence and flow dichroism with the pulsed laser method
Rheo-optical determination of flow birefringence and flow dichroism with the pulsed laser method online 29 August 2006 Rheo-optical measurements of the flow birefringence, flow dichroism systems under flow. However, the standard setup of an optical train, using phase modulation for the rheo-optical
Shahmansouri, M. [Department of Physics, Faculty of Science, Arak University, Arak 38156- 8 8349 (Iran, Islamic Republic of)] [Department of Physics, Faculty of Science, Arak University, Arak 38156- 8 8349 (Iran, Islamic Republic of); Mamun, A. A. [Department of Physics, Jahangirnagar University, Savar, Dhaka-1342 (Bangladesh)] [Department of Physics, Jahangirnagar University, Savar, Dhaka-1342 (Bangladesh)
2014-03-15T23:59:59.000Z
Linear and nonlinear propagation of dust-acoustic waves in a magnetized strongly coupled dusty plasma is theoretically investigated. The normal mode analysis (reductive perturbation method) is employed to investigate the role of ambient/external magnetic field, obliqueness, and effective electrostatic dust-temperature in modifying the properties of linear (nonlinear) dust-acoustic waves propagating in such a strongly coupled dusty plasma. The effective electrostatic dust-temperature, which arises from strong electrostatic interactions among highly charged dust, is considered as a dynamical variable. The linear dispersion relation (describing the linear propagation characteristics) for the obliquely propagating dust-acoustic waves is derived and analyzed. On the other hand, the Korteweg-de Vries equation describing the nonlinear propagation of the dust-acoustic waves (particularly, propagation of dust-acoustic solitary waves) is derived and solved. It is shown that the combined effects of obliqueness, magnitude of the ambient/external magnetic field, and effective electrostatic dust-temperature significantly modify the basic properties of linear and nonlinear dust-acoustic waves. The results of this work are compared with those observed by some laboratory experiments.
Protein Characterisation by Synchrotron Radiation Circular Dichroism (SRCD) Spectroscopy
Wallace, B.
2009-01-01T23:59:59.000Z
Circular dichroism (CD) spectroscopy is a well-established technique for the study of proteins. Synchrotron radiation circular dichroism (SRCD) spectroscopy extends the utility of conventional CD spectroscopy (i.e. using laboratory-based instruments) because the high light flux from a synchrotron enables collection of data to lower wavelengths, detection of spectra with higher signal-to-noise levels and measurements in the presence of strongly absorbing non-chiral components such as salts, buffers, lipids and detergents. This review describes developments in instrumentation, methodologies and bioinformatics that have enabled new applications of the SRCD technique for the study of proteins. It includes examples of the use of SRCD spectroscopy for providing static and dynamic structural information on molecules, including determinations of secondary structures of intact proteins and domains, assessment of protein stability, detection of conformational changes associated with ligand and drug binding, monitoring of environmental effects, examination of the processes of protein folding and membrane insertion, comparisons of mutant and modified proteins, identification of intermolecular interactions and complex formation, determination of the dispositions of proteins in membranes, identification of natively disordered proteins and their binding partners and examination of the carbohydrate components of glycoproteins. It also discusses how SRCD can be used in conjunction with macromolecular crystallography and other biophysical techniques to provide a more complete picture of protein structures and functions, including how proteins interact with other macromolecules and ligands. This review also includes a discussion of potential new applications in structural and functional genomics using SRCD spectroscopy and future instrumentation and bioinformatics developments that will enable such studies. Finally, the appendix describes a number of computational/bioinformatics resources for secondary structure analyses that take advantage of the improved data quality available from SRCD. In summary, this review discusses how SRCD can be used for a wide range of structural and functional studies of proteins.
Linear Dichroism in Resonant Inelastic X-Ray Scattering to Molecular
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9 5Let us countLighting SignLiisaLin WangSpin-Orbit
Mossbauer Spectroscopy as a Probe of Magnetization Dynamics in the Linear Iron(I) and Iron States *S Supporting Information ABSTRACT: The iron-57 Mossbauer spectra of the linear, two. Because of the lifetime of the measurement (10-8 to 10-9 s), iron-57 Mossbauer spectros- copy yielded
Investigations of Magnetic Overlayers at the Advanced Photon Source
Tobin, J G; Yu, S; Butterfield, M T
2009-06-26T23:59:59.000Z
Magnetic overlayers of Fe and Co have been investigated with X-ray Magnetic Circular Dichroism in X-ray Absorption Spectroscopy (XMCD-ABS) and Photoelectron Spectroscopy (PES), including Spin-Resolved Photoelectron Spectroscopy (SRPES), at Beamline 4 at the Advanced Photon Source (APS). Particular emphasis was placed upon the interrogation of the 2p levels of the Fe.
Mi, Chunting "Chris"
and the armature windings are on the stator while the rotor is the same as a SRM. Hence, it offers the ad- vantage permanent magnet (LDSPM) motor is particularly suitable for long stator applications due to its simple and low cost stator, which consists of only iron. This paper proposes a new LDSPM motor design
Azimuth ambiguity removal and non-linear force-free extrapolation of near-limb magnetic regions
Rudenko, G V; Anfnogentov, S A
2010-01-01T23:59:59.000Z
Possibilities in principle for satisfactory removal of the 180-azimuthal ambiguity in the transverse field of vector magnetograms and the extrapolation of magnetic fields independently of their position on the solar disk are shown. Revealed here is an exact correspondence between the estimated field and the nonpotential loop structure on the limb. The Metropolis's algorithm modified to work in spherical geometry is used to resolve the azimuthal ambiguity. Based on a version of the optimization method from Rudenko and Myshyakov (2009), we use corrected magnetograms as boundary conditions for magnetic field extrapolation in the nonlinear force-free approximation.
Schleyer, F.; Cairns, Iver H. [School of Physics, University of Sydney, NSW 2006 (Australia); Kim, E.-H. [Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)
2013-03-15T23:59:59.000Z
Linear mode conversion (LMC) is the linear transfer of energy from one wave mode to another in an inhomogeneous plasma. It is relevant to laboratory plasmas and multiple solar system radio emissions, such as continuum radiation from planetary magnetospheres and type II and III radio bursts from the solar corona and solar wind. This paper simulates LMC of waves defined by warm, magnetized fluid theory, specifically the conversion of Langmuir/z-mode waves to electromagnetic (EM) radiation. The primary focus is the calculation of the energy and power conversion efficiencies for LMC as functions of the angle of incidence {theta} of the Langmuir/z-mode wave, temperature {beta}=T{sub e}/m{sub e}c{sup 2}, adiabatic index {gamma}, and orientation angle {phi} between the ambient density gradient {nabla}N{sub 0} and ambient magnetic field B{sub 0} in a warm, unmagnetized plasma. The ratio of these efficiencies is found to agree well as a function of {theta}, {gamma}, and {beta} with an analytical relation that depends on the group speeds of the Langmuir/z and EM wave modes. The results demonstrate that the energy conversion efficiency {epsilon} is strongly dependent on {gamma}{beta}, {phi} and {theta}, with {epsilon}{proportional_to}({gamma}{beta}){sup 1/2} and {theta}{proportional_to}({gamma}{beta}){sup 1/2}. The power conversion efficiency {epsilon}{sub p}, on the other hand, is independent of {gamma}{beta} but does vary significantly with {theta} and {phi}. The efficiencies are shown to be maximum for approximately perpendicular density gradients ({phi} Almost-Equal-To 90 Degree-Sign ) and minimal for parallel orientation ({phi}=0 Degree-Sign ) and both the energy and power conversion efficiencies peak at the same {theta}.
Kane, A; Hertzog, D; Baumgartel, P; Lengefeld, J; Horsley, D; Schuler, B; Bakajin, O
2006-03-20T23:59:59.000Z
The purpose of this study is to design, fabricate and optimize microfluidic mixers to investigate the kinetics of protein secondary structure formation with Synchrotron Radiation Circular Dichroism (SRCD) spectroscopy. The mixers are designed to rapidly initiate protein folding reaction through the dilution of denaturant. The devices are fabricated out of fused silica, so that they are transparent in the UV. We present characterization of mixing in the fabricated devices, as well as the initial SRCD data on proteins inside the mixers.
B Wallace; R Janes
2011-12-31T23:59:59.000Z
CD (circular dichroism) spectroscopy is a well-established technique in structural biology. SRCD (synchrotron radiation circular dichroism) spectroscopy extends the utility and applications of conventional CD spectroscopy (using laboratory-based instruments) because the high flux of a synchrotron enables collection of data at lower wavelengths (resulting in higher information content), detection of spectra with higher signal-to-noise levels and measurements in the presence of absorbing components (buffers, salts, lipids and detergents). SRCD spectroscopy can provide important static and dynamic structural information on proteins in solution, including secondary structures of intact proteins and their domains, protein stability, the differences between wild-type and mutant proteins, the identification of natively disordered regions in proteins, and the dynamic processes of protein folding and membrane insertion and the kinetics of enzyme reactions. It has also been used to effectively study protein interactions, including protein-protein complex formation involving either induced-fit or rigid-body mechanisms, and protein-lipid complexes. A new web-based bioinformatics resource, the Protein Circular Dichroism Data Bank (PCDDB), has been created which enables archiving, access and analyses of CD and SRCD spectra and supporting metadata, now making this information publicly available. To summarize, the developing method of SRCD spectroscopy has the potential for playing an important role in new types of studies of protein conformations and their complexes.
Remote Sensing of Chromospheric Magnetic Fields via the Hanle and Zeeman Effects
J. Trujillo Bueno; R. Manso Sainz
2007-11-16T23:59:59.000Z
The only way to obtain reliable empirical information on the intensity and topology of the weak magnetic fields of the quiet solar chromosphere is via the measurement and rigorous physical interpretation of polarization signals in chromospheric spectral lines. The observed Stokes profiles reported here are due to the Hanle and Zeeman effects operating in a weakly magnetized plasma that is in a state far from local thermodynamic equilibrium. The physical origin of their enigmatic linear polarization Q and U components is the existence of atomic polarization in their metastable lower-levels, which permits the action of a dichroism mechanism that has nothing to do with the transverse Zeeman effect. It is also pointed out that the population imbalances and coherences among the Zeeman sublevels of such long-lived atomic levels can survive in the presence of horizontal magnetic fields having intensities in the gauss range, and produce significant polarization signals. Finally, it is shown how the most recent developments in the observation and theoretical modelling of weak polarization signals are facilitating fundamental new advances in our ability to investigate the magnetism of the outer solar atmosphere via spectropolarimetry.
Colossal anisotropy of the magnetic properties of doped lithium nitrodometalates
Antropov, Vladimir P [Ames Laboratory; Antonov, Victor N [Ames Laboratory
2014-09-01T23:59:59.000Z
We present a first-principles investigation of the electronic structure and physical properties of doped lithium nitridometalates Li2(Li1?xMx)N (LiMN) with M = Cr, Mn, Fe, Co, and Ni. The diverse properties include the equilibrium magnetic moments, magneto-crystalline anisotropy, magneto-optical Kerr spectra, and x-ray magnetic circular dichroism. We explain the colossal magnetic anisotropy in LiFeN by its unique electronic structure which ultimately leads to a series of unusual physical properties. The most unique property is a complete suppression of relativistic effects and freezing of orbital moments for in-plane orientation of the magnetization. This leads to the colossal spatial anisotropy of many magnetic properties including energy, Kerr, and dichroism effects. LiFeN is identified as an ultimate single-ion anisotropy system where a nearly insulating state can be produced by a spin orbital coupling alone. A very nontrivial strongly fluctuating and sign changing character of the magnetic anisotropy with electronic 3d-atomic doping is predicted theoretically. A large and highly anisotropic Kerr effect due to the interband transitions between atomic-like Fe 3d bands is found for LiFeN. A giant anisotropy of the x-ray magnetic circular dichroism for the Fe K spectrum and a very weak one for the Fe L2,3 spectra in LiFeN are also predicted.
Wallace,B.
2005-01-01T23:59:59.000Z
Circular dichroism (CD) spectroscopy has been employed for more than 50 years for the study of the structure and dynamics of proteins. It is now a workhorse of structural biology, finding applications in the determination of protein secondary structures, monitoring and deciphering protein folding, examining macromolecular interactions, and defining and quantitating protein-ligand binding. For the most part, CD studies have used laboratory-based instruments to measure electronic transitions in the far (190-250 nm), near ultraviolet (UV) (250-300 nm) and visible (> 400 nm) wavelength ranges, which have enabled studies of polypeptide backbones, aromatic amino acids and colored chromophores, respectively. Additional transitions exist at lower wavelengths in the vacuum ultraviolet (VUV) region (<190 nm); however, these transitions tend to be inaccessible to conventional CD instruments, due to the low intensity of their Xenon arc lamp light sources at wavelengths below190 nm. In 1980, the first synchrotron-based CD instruments were constructed, which took advantage of the high photon flux available from synchrotron light sources at these wavelengths. However, the technique of synchrotron radiation circular dichroism (SRCD) did not really take off until enabling studies had been done to show that additional data were obtainable for proteins in the VUV region, that these data were readily accessible with modern beamlines, and most importantly, that new applications of these data existed in structural molecular biology.
alfven fluctuations linear: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
of open and expanding magnetic field configuration with a realistic temperature distribution. We compute the maximum transversal velocity of both linear and non-linear Alfven...
Kumar, Punith V., E-mail: drvldayal@gmail.com; Manju, M. R., E-mail: drvldayal@gmail.com; Dayal, Vijaylakshmi, E-mail: drvldayal@gmail.com [Department of Physics, Maharaja Institute of Technology, Mysore-571438, Karnataka (India)
2014-04-24T23:59:59.000Z
We present a comprehensive study on origin of Spin Glass (SG) property in polycrystalline La{sub 0.5}Bi{sub 0.5}MnO{sub 3} perovskite oxide using linear and higher order ac susceptibility (?) measurements. The third order harmonic susceptibility (?{sub 3}) vs. temperature (K) with varying magnetic fields from 0.95 to 9.45 Oe and the divergence in their ?{sub 3} (max) allows us to infer the SG behavior occurring in the sample possibly due to co-operative freezing of the spins.
Wallace, B.A.; Sutherland, J.; Gekko, K.; Hoffmann, S. V.; Lin, Y.-H.; Tao, Y.; Wien, F.; Janes, R. W.
2011-09-01T23:59:59.000Z
Circular dichroism (CD) spectroscopy is a well-established technique in structural biology. The use of synchrotron radiation as an intense light source for these measurements extends the applications possible using lab-based instruments. In recent years, there has been a major growth in synchrotron radiation circular dichroism (SRCD) beamlines worldwide, including ones at the NSLS, ISA, SRS, HiSOR, BSRF, NSRRC, SOLEIL, Diamond, TERAS, BESSYII, and ANKA synchrotrons. Through the coordinated efforts of beamline scientists and users at these sites, important proof-of-principle studies have been done enabling the method to be developed for novel and productive studies on biological systems. This paper describes the characteristics of SRCD beamlines and some of the new types of applications that have been undertaken using these beamlines.
Shaon Sahoo; Soumya Kanti Ganguly
2015-02-01T23:59:59.000Z
Contrary to the actual nonlinear Glauber model (NLGM), the linear Glauber model (LGM) is exactly solvable, although the detailed balance condition is not generally satisfied. This motivates us to address the issue of writing the transition rate ($w_j$) in a best possible linear form such that the mean squared error in satisfying the detailed balance condition is least. The advantage of this work is that, by studying the LGM analytically, we will be able to anticipate how the kinetic properties of an arbitrary Ising system depend on the temperature and the coupling constants. The analytical expressions for the optimal values of the parameters involved in the linear $w_j$ are obtained using a simple Moore-Penrose pseudoinverse matrix. This approach is quite general, in principle applicable to any system and can reproduce the exact results for one dimensional Ising system. In the continuum limit, we get a linear time-dependent Ginzburg-Landau (TDGL) equation from the Glauber's microscopic model of non-conservative dynamics. We analyze the critical and dynamic properties of the model, and show that most of the important results obtained in different studies can be reproduced by our new mathematical approach. We will also show in this paper that the effect of magnetic field can easily be studied within our approach; in particular, we show that the inverse of relaxation time changes quadratically with (weak) magnetic field and that the fluctuation-dissipation theorem is valid for our model.
Kliman, G.B.; Brynsvold, G.V.; Jahns, T.M.
1989-08-22T23:59:59.000Z
A winding and method of winding for a submersible linear pump for pumping liquid sodium are disclosed. The pump includes a stator having a central cylindrical duct preferably vertically aligned. The central vertical duct is surrounded by a system of coils in slots. These slots are interleaved with magnetic flux conducting elements, these magnetic flux conducting elements forming a continuous magnetic field conduction path along the stator. The central duct has placed therein a cylindrical magnetic conducting core, this core having a cylindrical diameter less than the diameter of the cylindrical duct. The core once placed to the duct defines a cylindrical interstitial pumping volume of the pump. This cylindrical interstitial pumping volume preferably defines an inlet at the bottom of the pump, and an outlet at the top of the pump. Pump operation occurs by static windings in the outer stator sequentially conveying toroidal fields from the pump inlet at the bottom of the pump to the pump outlet at the top of the pump. The winding apparatus and method of winding disclosed uses multiple slots per pole per phase with parallel winding legs on each phase equal to or less than the number of slots per pole per phase. The slot sequence per pole per phase is chosen to equalize the variations in flux density of the pump sodium as it passes into the pump at the pump inlet with little or no flux and acquires magnetic flux in passage through the pump to the pump outlet. 4 figs.
Kliman, Gerald B. (Schenectady, NY); Brynsvold, Glen V. (San Jose, CA); Jahns, Thomas M. (Schenectady, NY)
1989-01-01T23:59:59.000Z
A winding and method of winding for a submersible linear pump for pumping liquid sodium is disclosed. The pump includes a stator having a central cylindrical duct preferably vertically aligned. The central vertical duct is surrounded by a system of coils in slots. These slots are interleaved with magnetic flux conducting elements, these magnetic flux conducting elements forming a continuous magnetic field conduction path along the stator. The central duct has placed therein a cylindrical magnetic conducting core, this core having a cylindrical diameter less than the diameter of the cylindrical duct. The core once placed to the duct defines a cylindrical interstitial pumping volume of the pump. This cylindrical interstitial pumping volume preferably defines an inlet at the bottom of the pump, and an outlet at the top of the pump. Pump operation occurs by static windings in the outer stator sequentially conveying toroidal fields from the pump inlet at the bottom of the pump to the pump outlet at the top of the pump. The winding apparatus and method of winding disclosed uses multiple slots per pole per phase with parallel winding legs on each phase equal to or less than the number of slots per pole per phase. The slot sequence per pole per phase is chosen to equalize the variations in flux density of the pump sodium as it passes into the pump at the pump inlet with little or no flux and acquires magnetic flux in passage through the pump to the pump outlet.
A linear induction motor conveyer
Solinsky, Kenneth Sheldon
1973-01-01T23:59:59.000Z
wave 14. Fundamentals of inducing a magnetic field. 25 15. Dsr made of conducting material placed above six current carrying wire . . . . . . . . . . . . . . . . . . . 26 16. Change in conductor's magnetic field with time. 27 17. Origin of. forces..., it is pos- sible to design a mears of moving certain objects, such that the arly moving parts of the entire convey- ing system are the items to be moved. Such a system can be used to move any item made of a nonmagnetic conductor. A linear inductior...
Enhanced Magnetism of Fe3O4 Nanoparticles with Ga Doping
Pool, V. L.; Klem, M. T.; Chorney, C. L.; Arenholz, E.; Idzerda, Y.U.
2010-10-22T23:59:59.000Z
Magnetic (Ga{sub x}Fe{sub 1-x}){sub 3}O{sub 4} nanoparticles with 5%-33% gallium doping (x = 0.05-0.33) were measured using x-ray absorption spectroscopy and x-ray magnetic circular dichroism to determine that the Ga dopant is substituting for Fe{sub 3+} as Ga{sub 3+} in the tetrahedral A-site of the spinel structure, resulting in an overall increase in the total moment of the material. Frequency-dependent alternating-current magnetic susceptibility measurements showed these particles to be weakly interacting with a reduction of the cubic anisotropy energy term with Ga concentration. The element-specific dichroism spectra show that the average Fe moment is observed to increase with Ga concentration, a result consistent with the replacement of A-site Fe by Ga.
Laced permanent magnet quadrupole drift tube magnets
Feinberg, B.; Behrsing, G.U.; Halbach, K.; Marks, J.S.; Morrison, M.E.; Nelson, D.H.
1989-03-01T23:59:59.000Z
Twenty-three laced permanent magnet quadrupole drift tube magnets have been constructed, tested, and installed in the SuperHILAC heavy ion linear accelerator at LBL, marking the first accelerator use of this new type of quadrupole. The magnets consist of conventional tape-wound quadrupole electromagnets, using iron pole-pieces, with permanent magnet material (samarium cobalt) inserted between the poles to reduce the effects of saturation. The iron is preloaded with magnetic flux generated by the permanent magnet material, resulting in an asymmetrical saturation curve. Since the polarity of the individual quadrupole magnets in a drift tube linac is never reversed, we can take advantage of this asymmetrical saturation to provide about 20% greater focusing strength than is available with conventional quadrupoles, while replacing the vanadium permendur poletips with iron poletips. Comparisons between these magnets and conventional tape-wound quadrupoles will be presented. 3 refs., 5 figs.
On Possible Light-Torsion Mixing in Background Magnetic Field
S. I. Kruglov
2009-07-10T23:59:59.000Z
The interaction of the light with propagating axial torsion fields in the presence of an external magnetic field has been investigated. Axial torsion fields appearing in higher derivative quantum gravity possess two states, with spin one and zero, with different masses. The torsion field with spin-0 state is a ghost that can be removed if its mass is infinite. We investigate the possibility when the light mixes with the torsion fields resulting in the effect of vacuum birefringence and dichroism. The expressions for ellipticity and the rotation of light polarization axis depending on the coupling constant and the external magnetic field have been obtained.
Thomas Wiegelmann; Bernd Inhester
2006-12-21T23:59:59.000Z
The space mission STEREO will provide images from two viewpoints. An important aim of the STEREO mission is to get a 3D view of the solar corona. We develop a program for the stereoscopic reconstruction of 3D coronal loops from images taken with the two STEREO spacecraft. A pure geometric triangulation of coronal features leads to ambiguities because the dilute plasma emissions complicates the association of features in image 1 with features in image 2. As a consequence of these problems the stereoscopic reconstruction is not unique and multiple solutions occur. We demonstrate how these ambiguities can be resolved with the help of different coronal magnetic field models (potential, linear and non-linear force-free fields). The idea is that, due to the high conductivity in the coronal plasma, the emitting plasma outlines the magnetic field lines. Consequently the 3D coronal magnetic field provides a proxy for the stereoscopy which allows to eliminate inconsistent configurations. The combination of stereoscopy and magnetic modelling is more powerful than one of these tools alone. We test our method with the help of a model active region and plan to apply it to the solar case as soon as STEREO data become available.
Voltage regulation in linear induction accelerators
Parsons, William M. (Santa Fe, NM)
1992-01-01T23:59:59.000Z
Improvement in voltage regulation in a Linear Induction Accelerator wherein a varistor, such as a metal oxide varistor, is placed in parallel with the beam accelerating cavity and the magnetic core. The non-linear properties of the varistor result in a more stable voltage across the beam accelerating cavity than with a conventional compensating resistance.
Voltage regulation in linear induction accelerators
Parsons, W.M.
1992-12-29T23:59:59.000Z
Improvement in voltage regulation in a linear induction accelerator wherein a varistor, such as a metal oxide varistor, is placed in parallel with the beam accelerating cavity and the magnetic core is disclosed. The non-linear properties of the varistor result in a more stable voltage across the beam accelerating cavity than with a conventional compensating resistance. 4 figs.
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |Is Your HomeLatestCenter (LMI-EFRC) -Choices toLeeLinear Accelerator
Electronic Non-Contacting Linear Position Measuring System
Post, Richard F. (Walnut Creek, CA)
2005-06-14T23:59:59.000Z
A non-contacting linear position location system employs a special transmission line to encode and transmit magnetic signals to a receiver on the object whose position is to be measured. The invention is useful as a non-contact linear locator of moving objects, e.g., to determine the location of a magnetic-levitation train for the operation of the linear-synchronous motor drive system.
Interaction of Ferromagnetic and Superconducting Permanent Magnets...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
permanent magnet track, was put into operation. A vehicle for 2 passengers, equipped with linear drive propulsion, a noncontact energy supply, a second braking system, and various...
T. T. Moh
2015-01-20T23:59:59.000Z
goal of this course is to enable you to recognize linear algebra problems ... descriptions of other people's solutions to problems that use linear algebra and to
STANFORD LINEAR ACCELERATOR CENTER RECORDS CONTROL SCHEDULE
Wechsler, Risa H.
to project justification, staffing, initiation, or execution; project management plans, records managementSTANFORD LINEAR ACCELERATOR CENTER PEP-II RECORDS CONTROL SCHEDULE SCOPE: This schedule covers records of the PEP-II project, regardless of format (paper, electronic, magnetic, photographic, etc
Villalba-Chávez, S., E-mail: selymv@gmail.com; Müller, C., E-mail: c.mueller@tp1.uni-duesseldorf.de
2013-12-15T23:59:59.000Z
Absorption and dispersion of probe photons in the field of a high-intensity circularly polarized laser wave are investigated. The optical theorem is applied for determining the absorption coefficients in terms of the imaginary part of the vacuum polarization tensor. Compact expressions for the vacuum refraction indices and the photon absorption coefficients are obtained in various asymptotic regimes of interest. The outcomes of this analysis reveal that, far from the region relatively close to the threshold of the two-photon reaction, the birefringence and dichroism of the vacuum are small and, in some cases, strongly suppressed. On the contrary, in a vicinity of the region in which the photo-production of a pair occurs, these optical properties are manifest with lasers of moderate intensities. We take advantage of such a property in the search of minicharged particles by considering high-precision polarimetric experiments. In addition, Raman-like electromagnetic waves resulting from the inelastic part of the vacuum polarization tensor are suggested as an alternative form for finding exclusion limits on these hypothetical charge carriers. The envisaged parameters of upcoming high-intensity laser facilities are used for establishing upper bounds on the minicharged particles. -- Highlights: •Via dichroism and birefringence of the vacuum by a strong laser wave, minicharged particles can be probed. •The discovery potential is the highest in a vicinity of the first pair production threshold. •As alternative observable, Raman scattered waves are put forward.
Generalized Linear Quadratic Control
Gattami, Ather Said
We consider the problem of stochastic finite- and infinite-horizon linear quadratic control under power constraints. The calculations of the optimal control law can be done off-line as in the classical linear quadratic ...
The Microscopic Linear Dynamics
Penny, Will
The Microscopic Brain Will Penny Linear Dynamics Exponentials Matrix Exponential Eigendecomposition Dynamical Modes Nodes State Space Saddles Oscillations Spirals Centres Offsets Retinal Circuit Nullclines Stability Spiking Neurons Fitzhugh-Nagumo Nonlinear Dynamics Linearization Nonlinear Oscillation Excitable
Zeghib, Abdelghani
Introduction Results Linear Dynamics Lorentz Dynamics Actions of discrete groups on stationary Piccione) Geodeycos Meeting, Lyon, 28-30 April 2010 Abdelghani Zeghib Dynamics on Lorentz manifolds #12;Introduction Results Linear Dynamics Lorentz Dynamics Motivations and questions Examples 1 Introduction
Introduction to Linear Relaxations
Introduction to Linear Relaxations by R. Baker Kearfott Department of Mathematics University relaxations; . discuss validation of linear relaxations. Intro. Linear Relaxations December, 2003 Taylor, . . . , m 2 , where # : R n # R and c i , g i : R n # R are guaranteed to be within one of the x # that has
Design and construction of a precision tubular linear motor and controller
Murphy, Bryan Craig
2004-09-30T23:59:59.000Z
A design for a novel tubular high-precision direct-drive brushless linear motor has been developed. The novelty of the design lies in the orientation of the magnets in the mover. In conventional linear motors the magnets of the armature...
Demmel, James; Holtz, Olga; Dumitriu, Ioana
2007-01-01T23:59:59.000Z
than other basic linear algebra subroutines. AcknowledgmentsApplied Numerical Linear Algebra. SIAM, 1997. [23] J.algorithms in numerical linear algebra. SIAM Review, 20:740–
Bettinger, J.S.
2010-01-01T23:59:59.000Z
photomagnetism in the spinel ferrite (Mn,Zn,Fe)3O4 as seendoped garnets 1 , doped spinel ferrites 2 , doped perovskiteIn the doped garnets and ferrites, the microscopic origin of
Fault tolerant linear actuator
Tesar, Delbert
2004-09-14T23:59:59.000Z
In varying embodiments, the fault tolerant linear actuator of the present invention is a new and improved linear actuator with fault tolerance and positional control that may incorporate velocity summing, force summing, or a combination of the two. In one embodiment, the invention offers a velocity summing arrangement with a differential gear between two prime movers driving a cage, which then drives a linear spindle screw transmission. Other embodiments feature two prime movers driving separate linear spindle screw transmissions, one internal and one external, in a totally concentric and compact integrated module.
Using Linearity Web Copyright 2007
Rodriguez, Carlos
Using Linearity Web Rev. 2.0 May 2007 Copyright © 2007 #12;Using Linearity Web i Contents Introduction to Linearity Web.............................................................................1 Features, Benefits, and Value of Linearity Web..............................................1 Before You
Radio frequency quadrupole resonator for linear accelerator
Moretti, Alfred (Downers Grove, IL)
1985-01-01T23:59:59.000Z
An RFQ resonator for a linear accelerator having a reduced level of interfering modes and producing a quadrupole mode for focusing, bunching and accelerating beams of heavy charged particles, with the construction being characterized by four elongated resonating rods within a cylinder with the rods being alternately shorted and open electrically to the shell at common ends of the rods to provide an LC parallel resonant circuit when activated by a magnetic field transverse to the longitudinal axis.
W. B. Vasantha Kandasamy; Florentin Smarandache
2008-07-18T23:59:59.000Z
In this book, the authors introduce the notion of Super linear algebra and super vector spaces using the definition of super matrices defined by Horst (1963). This book expects the readers to be well-versed in linear algebra. Many theorems on super linear algebra and its properties are proved. Some theorems are left as exercises for the reader. These new class of super linear algebras which can be thought of as a set of linear algebras, following a stipulated condition, will find applications in several fields using computers. The authors feel that such a paradigm shift is essential in this computerized world. Some other structures ought to replace linear algebras which are over a century old. Super linear algebras that use super matrices can store data not only in a block but in multiple blocks so it is certainly more powerful than the usual matrices. This book has 3 chapters. Chapter one introduces the notion of super vector spaces and enumerates a number of properties. Chapter two defines the notion of super linear algebra, super inner product spaces and super bilinear forms. Several interesting properties are derived. The main application of these new structures in Markov chains and Leontief economic models are also given in this chapter. The final chapter suggests 161 problems mainly to make the reader understand this new concept and apply them.
Linear nanometric tunnel junction sensors with exchange pinned sensing layer
Leitao, D. C., E-mail: dleitao@inesc-mn.pt; Silva, A. V.; Cardoso, S. [INESC-MN and IN, Rua Alves Redol 9, 1000-029 Lisboa (Portugal); Instituto Superior Técnico (IST), Universidade de Lisboa, Av. Rovisco Pais, 1000-029 Lisboa (Portugal); Ferreira, R.; Paz, E.; Deepack, F. L. [INL, Av. Mestre Jose Veiga, 4715-31 Braga (Portugal); Freitas, P. P. [INESC-MN and IN, Rua Alves Redol 9, 1000-029 Lisboa (Portugal); INL, Av. Mestre Jose Veiga, 4715-31 Braga (Portugal)
2014-05-07T23:59:59.000Z
Highly sensitive nanosensors with high spatial resolution provide the necessary features for high accuracy imaging of isolated magnetic nanoparticles. In this work, we report the fabrication and characterization of MgO-barrier magnetic tunnel junction nanosensors, with two exchange-pinned electrodes. The perpendicular magnetization configuration for field sensing is set using a two-step annealing process, where the second annealing temperature was optimized to yield patterned sensors responses with improved linearity. The optimized circular nanosensors show sensitivities up to 0.1%/Oe, larger than previously reported for nanometric sensors and comparable to micrometric spin-valves. Our strategy avoids the use of external permanent biasing or demagnetizing fields (large for smaller structures) to achieve a linear response, enabling the control of the linear operation range using only the stack and thus providing a small footprint device.
Linear Motor Powered Transportation
Thornton, Richard D.
This special issue on linear-motor powered transportation covers both supporting technologies and innovative transport systems in various parts of the World, as this technology moves from the lab to commercial operations. ...
Wave propagation in the magnetic sun
T. Hartlep; M. S. Miesch; N. N. Mansour
2008-05-03T23:59:59.000Z
This paper reports on efforts to simulate wave propagation in the solar interior. Presented is work on extending a numerical code for constant entropy acoustic waves in the absence of magnetic fields to the case where magnetic fields are present. A set of linearized magnetohydrodynamic (MHD) perturbation equations has been derived and implemented.
Optimization Online - Linear-quadratic control problem with a linear ...
L Faybusovich
2003-12-19T23:59:59.000Z
Dec 19, 2003 ... Abstract: We describe a complete solution of the linear-quaratic control problem with the linear term in the objective function on a semiinfinite ...
6, 74277469, 2006 Linear ozone
Boyer, Edmond
ACPD 6, 74277469, 2006 Linear ozone photochemistry parametrizations A. J. Geer et al. Title Page Chemistry and Physics Discussions Evaluation of linear ozone photochemistry parametrizations Linear ozone photochemistry parametrizations A. J. Geer et al. Title Page Abstract Introduction
Magnetic phases and structural properties in Co/Ru superlattices
Alayo, W.; Tafur, Miguel; Baggio-Saitovitch, E. [Centro Brasileiro de Pesquisas Fisicas, Rio de Janeiro 22290-180 (Brazil); Pelegrini, F. [Instituto de Fisica, Universidade Federal de Goias, Goiania 74001-970 (Brazil); Nascimento, V. P. [Centro Universitario Norte do Espirito Santo, Universidade Federal do Espirito Santo, Sao Mateus 29933-415 (Brazil)
2009-05-01T23:59:59.000Z
We report studies by x-ray diffraction, ferromagnetic resonance (FMR), and x-ray magnetic circular dichroism (XMCD) in Co/Ru superlattices grown by magnetron sputtering. We studied the [Co(50 A)/Ru(t{sub Ru})]{sub 20} samples, which were deposited at room temperature on Si substrates with the Ru thicknesses, t{sub Ru}, varying between 9 and 33 A. The main and secondary uniform absorption modes, observed in the FMR spectra, are associated with the Co/Ru interfaces and the bulk Co regions, respectively. The main mode becomes more intense than the secondary one for increasing t{sub Ru}. This is attributed to the roughness and/or atomic interdiffusion, which leads, with increasing t{sub Ru}, to an increasing volume of Co/Ru interfacial regions and a decreasing volume of pure Co regions. The XMCD measurements provide Co spin magnetic moments lower than the bulk Co value, confirming the presence of a Co magnetic region with a lower local effective magnetization attributed to the Co/Ru interfaces.
Robust Linear Optimization With Recourse
2010-05-19T23:59:59.000Z
We propose an approach to two-stage linear optimization with recourse that does ... Linear optimization with recourse was first introduced by Dantzig in [17] as a ...
Spectral learning of linear dynamics from generalised-linear observations
a non-linear and non-Gaussian observation process. We use this approach to obtain estimates to the generalised-linear regression model [8]), where the expected value of an observation is given by a monotonicSpectral learning of linear dynamics from generalised-linear observations with application
Linear Quantum Feedback Networks
J. Gough; R. Gohm; M. Yanagisawa
2008-07-15T23:59:59.000Z
The mathematical theory of quantum feedback networks has recently been developed for general open quantum dynamical systems interacting with bosonic input fields. In this article we show, for the special case of linear dynamical systems Markovian systems with instantaneous feedback connections, that the transfer functions can be deduced and agree with the algebraic rules obtained in the nonlinear case. Using these rules, we derive the the transfer functions for linear quantum systems in series, in cascade, and in feedback arrangements mediated by beam splitter devices.
Ito, Keita; Sanai, Tatsunori; Yasutomi, Yoko; Toko, Kaoru; Honda, Syuta; Suemasu, Takashi [Institute of Applied Physics, Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan)] [Institute of Applied Physics, Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Zhu, Siyuan; Kimura, Akio [Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan)] [Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526 (Japan); Ueda, Shigenori [Synchrotron X-ray Station at SPring-8, National Institute for Materials Science (NIMS), 1-1-1 Kouto, Sayo-cho, Hyogo 679-5148 (Japan)] [Synchrotron X-ray Station at SPring-8, National Institute for Materials Science (NIMS), 1-1-1 Kouto, Sayo-cho, Hyogo 679-5148 (Japan); Takeda, Yukiharu; Saitoh, Yuji [Condensed Matter Science Division, Japan Atomic Energy Agency (JAEA), 1-1-1 Kouto, Sayo-cho, Hyogo 679-5148 (Japan)] [Condensed Matter Science Division, Japan Atomic Energy Agency (JAEA), 1-1-1 Kouto, Sayo-cho, Hyogo 679-5148 (Japan); Imai, Yoji [Institute of Applied Physics, Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan) [Institute of Applied Physics, Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565 (Japan)
2013-12-02T23:59:59.000Z
We evaluated electronic structures and magnetic moments in Co{sub 3}FeN epitaxial films on SrTiO{sub 3}(001). The experimentally obtained hard x-ray photoemission spectra of the Co{sub 3}FeN film have a good agreement with those calculated. Site averaged spin magnetic moments deduced by x-ray magnetic circular dichroism were 1.52 ?{sub B} per Co atom and 2.08 ?{sub B} per Fe atom at 100 K. They are close to those of Co{sub 4}N and Fe{sub 4}N, respectively, implying that the Co and Fe atoms randomly occupy the corner and face-centered sites in the Co{sub 3}FeN unit cell.
Linear Programming Environmental
Nagurney, Anna
Linear Program to control air pollution was developed in 1968 by Teller, which minimized cost Fall 2006 #12;Topics · Introduction · Background · Air · Land · Water #12;Introduction · "The United States spends more than 2% of its gross domestic product on pollution control, and this is more than any
W. B. Vasantha Kandasamy; Florentin Smarandache
2010-12-08T23:59:59.000Z
In this book we use only special types of intervals and introduce the notion of different types of interval linear algebras and interval vector spaces using the intervals of the form [0, a] where the intervals are from Zn or Z+ \\cup {0} or Q+ \\cup {0} or R+ \\cup {0}. A systematic development is made starting from set interval vector spaces to group interval vector spaces. Vector spaces are taken as interval polynomials or interval matrices or just intervals over suitable sets or semigroups or groups. Main feature of this book is the authors have given over 350 examples. This book has six chapters. Chapter one is introductory in nature. Chapter two introduces the notion of set interval linear algebras of type one and two. Set fuzzy interval linear algebras and their algebras and their properties are discussed in chapter three. Chapter four introduces several types of interval linear bialgebras and bivector spaces and studies them. The possible applications are given in chapter five. Chapter six suggests nearly 110 problems of all levels.
MAGNETOHYDRODYNAMIC SHALLOW WATER WAVES: LINEAR ANALYSIS
Heng, Kevin [Institute for Advanced Study, School of Natural Sciences, Einstein Drive, Princeton, NJ 08540 (United States); Spitkovsky, Anatoly, E-mail: heng@ias.ed, E-mail: anatoly@astro.princeton.ed [Department of Astrophysical Sciences, Peyton Hall, Princeton University, Princeton, NJ 08544 (United States)
2009-10-01T23:59:59.000Z
We present a linear analysis of inviscid, incompressible, magnetohydrodynamic (MHD) shallow water systems. In spherical geometry, a generic property of such systems is the existence of five wave modes. Three of them (two magneto-Poincare modes and one magneto-Rossby mode) are previously known. The other two wave modes are strongly influenced by the magnetic field and rotation, and have substantially lower angular frequencies; as such, we term them 'magnetostrophic modes'. We obtain analytical functions for the velocity, height, and magnetic field perturbations in the limit that the magnitude of the MHD analogue of Lamb's parameter is large. On a sphere, the magnetostrophic modes reside near the poles, while the other modes are equatorially confined. Magnetostrophic modes may be an ingredient in explaining the frequency drifts observed in Type I X-ray bursts from neutron stars.
Bath, G.D.; Jahren, C.E.; Rosenbaum, J.G. [Geological Survey, Denver, CO (USA); Baldwin, M.J. [Fenix and Scisson, Inc., Mercury, NV (USA)
1983-12-31T23:59:59.000Z
Air and ground magnetic anomalies in the Climax stock area of the NTS help define the gross configuration of the stock and detailed configuration of magnetized rocks at the Boundary and Tippinip faults that border the stock. Magnetizations of geologic units were evaluated by measurements of magnetic properties of drill core, minimum estimates of magnetizations from ground magnetic anomalies for near surface rocks, and comparisons of measured anomalies with anomalies computed by a three-dimensional forward program. Alluvial deposits and most sedimentary rocks are nonmagnetic, but drill core measurements reveal large and irregular changes in magnetization for some quartzites and marbles. The magnetizations of quartz monzonite and granodiorite near the stock surface are weak, about 0.15 A/m, and increase at a rate of 0.00196 A/m/m to 1.55 A/m, at depths greater than 700 m (2300 ft). The volcanic rocks of the area are weakly magnetized. Aeromagnetic anomalies 850 m (2800 ft) above the stock are explained by a model consisting of five vertical prisms. Prisms 1, 2, and 3 represent the near surface outline of the stock, prism 4 is one of the models developed by Whitehill (1973), and prism 5 is modified from the model developed by Allingham and Zietz (1962). Most of the anomaly comes from unsampled and strongly-magnetized deep sources that could be either granite or metamorphosed sedimentary rocks. 48 refs., 23 figs., 3 tabs.
Design and sizing of electromagnetic linear actuators for valve applications
Paris-Sud XI, Université de
Page 1/9 Design and sizing of electromagnetic linear actuators for valve applications J.C Vannier1. These structures have been studied in order to drive the valves of a car motor. According to general specifications magnet, valves. 1. Introduction, general specifications The valves which can be found in thermal engines
Position sensor for linear synchronous motors employing halbach arrays
Post, Richard Freeman
2014-12-23T23:59:59.000Z
A position sensor suitable for use in linear synchronous motor (LSM) drive systems employing Halbach arrays to create their magnetic fields is described. The system has several advantages over previously employed ones, especially in its simplicity and its freedom from being affected by weather conditions, accumulated dirt, or electrical interference from the LSM system itself.
Crozier, Richard Carson
2014-06-30T23:59:59.000Z
Combined electrical and structural models of five types of permanent magnet linear electrical machines suitable for direct-drive power take-off on wave energy applications are presented. Electromagnetic models were ...
Magnetic Field Safety Magnetic Field Safety
McQuade, D. Tyler
Magnetic Field Safety Training #12;Magnetic Field Safety Strong Magnetic Fields exist around energized magnets. High magnetic fields alone are a recognized hazard only for personnel with certain medical conditions such as pacemakers, magnetic implants, or embedded shrapnel. In addition, high magnetic
Are Cluster Magnetic Fields Primordial ?
Robi Banerjee; Karsten Jedamzik
2004-09-07T23:59:59.000Z
We present results of a detailed and fully non-linear numerical and analytical investigation of magnetic field evolution from the very earliest cosmic epochs to the present. We find that, under reasonable assumptions concerning the efficiency of a putative magnetogenesis era during cosmic phase transitions, surprisingly strong magnetic fields 10^{-13} - 10^{-11} Gauss, on comparatively small scales 100 pc - 10 kpc may survive to the present. Building on prior work on the evolution of magnetic fields during the course of gravitational collapse of a cluster, which indicates that pre-collapse fields of 4\\times 10^{-12} Gauss extant on small scales may suffice to produce clusters with acceptable Faraday rotation measures, we question the widely hold view that cluster magnetic fields may not be entirely of primordial origin.
Thomas R. Hemmert; Ulf-G. Meissner; Sven Steininger
1998-11-09T23:59:59.000Z
We present an analytic and parameter-free expression for the momentum dependence of the strange magnetic form factor of the nucleon and its corresponding radius which has been derived in Heavy Baryon Chiral Perturbation Theory. We also discuss a model-independent relation between the isoscalar magnetic and the strange magnetic form factors of the nucleon based on chiral symmetry and SU(3) only. These limites are used to derive bounds on the strange magnetic moment of the proton from the recent measurement by the SAMPLE collaboration.
Henneaux, Marc; Teitelboim, Claudio [Physique Theorique et Mathematique and International Solvay Institutes, Universite Libre de Bruxelles, Campus Plaine C. P. 231, B-1050 Brussels (Belgium) and Centro de Estudios Cientificos (CECS), Valdivia (Chile); Centro de Estudios Cientificos (CECS), Valdivia (Chile)
2005-01-15T23:59:59.000Z
We show that duality transformations of linearized gravity in four dimensions, i.e., rotations of the linearized Riemann tensor and its dual into each other, can be extended to the dynamical fields of the theory so as to be symmetries of the action and not just symmetries of the equations of motion. Our approach relies on the introduction of two superpotentials, one for the spatial components of the spin-2 field and the other for their canonically conjugate momenta. These superpotentials are two-index, symmetric tensors. They can be taken to be the basic dynamical fields and appear locally in the action. They are simply rotated into each other under duality. In terms of the superpotentials, the canonical generator of duality rotations is found to have a Chern-Simons-like structure, as in the Maxwell case.
Buttram, M.T.; Ginn, J.W.
1988-06-21T23:59:59.000Z
A linear induction accelerator includes a plurality of adder cavities arranged in a series and provided in a structure which is evacuated so that a vacuum inductance is provided between each adder cavity and the structure. An energy storage system for the adder cavities includes a pulsed current source and a respective plurality of bipolar converting networks connected thereto. The bipolar high-voltage, high-repetition-rate square pulse train sets and resets the cavities. 4 figs.
Combustion powered linear actuator
Fischer, Gary J. (Albuquerque, NM)
2007-09-04T23:59:59.000Z
The present invention provides robotic vehicles having wheeled and hopping mobilities that are capable of traversing (e.g. by hopping over) obstacles that are large in size relative to the robot and, are capable of operation in unpredictable terrain over long range. The present invention further provides combustion powered linear actuators, which can include latching mechanisms to facilitate pressurized fueling of the actuators, as can be used to provide wheeled vehicles with a hopping mobility.
Jacques Carolan; Chris Harrold; Chris Sparrow; Enrique Martín-López; Nicholas J. Russell; Joshua W. Silverstone; Peter J. Shadbolt; Nobuyuki Matsuda; Manabu Oguma; Mikitaka Itoh; Graham D. Marshall; Mark G. Thompson; Jonathan C. F. Matthews; Toshikazu Hashimoto; Jeremy L. O'Brien; Anthony Laing
2015-05-05T23:59:59.000Z
Linear optics underpins tests of fundamental quantum mechanics and computer science, as well as quantum technologies. Here we experimentally demonstrate the longstanding goal of a single reprogrammable optical circuit that is sufficient to implement all possible linear optical protocols up to the size of that circuit. Our six-mode universal system consists of a cascade of 15 Mach-Zehnder interferometers with 30 thermo-optic phase shifters integrated into a single photonic chip that is electrically and optically interfaced for arbitrary setting of all phase shifters, input of up to six photons and their measurement with a 12 single-photon detector system. We programmed this system to implement heralded quantum logic and entangling gates, boson sampling with verification tests, and six-dimensional complex Hadamards. We implemented 100 Haar random unitaries with average fidelity 0.999 $\\pm$ 0.001. Our system is capable of switching between these and any other linear optical protocol in seconds. These results point the way to applications across fundamental science and quantum technologies.
The International Linear Collider
Barish, Barry
2013-01-01T23:59:59.000Z
In this article, we describe the key features of the recently completed technical design for the International Linear Collider (ILC), a 200-500 GeV linear electron-positron collider (expandable to 1 TeV) that is based on 1.3 GHz superconducting radio-frequency (SCRF) technology. The machine parameters and detector characteristics have been chosen to complement the Large Hadron Collider physics, including the discovery of the Higgs boson, and to further exploit this new particle physics energy frontier with a precision instrument. The linear collider design is the result of nearly twenty years of R&D, resulting in a mature conceptual design for the ILC project that reflects an international consensus. We summarize the physics goals and capability of the ILC, the enabling R&D and resulting accelerator design, as well as the concepts for two complementary detectors. The ILC is technically ready to be proposed and built as a next generation lepton collider, perhaps to be built in stages beginning as a Hig...
Modeling spin magnetization transport in a spatially varying magnetic field
Rico A. R. Picone; Joseph L. Garbini; John A. Sidles
2014-08-13T23:59:59.000Z
We present a framework for modeling the transport of any number of globally conserved quantities in any spatial configuration and apply it to obtain a model of magnetization transport for spin-systems that is valid in new regimes (including high-polarization). The framework allows an entropy function to define a model that explicitly respects the laws of thermodynamics. Three facets of the model are explored. First, it is expressed as nonlinear partial differential equations that are valid for the new regime of high dipole-energy and polarization. Second, the nonlinear model is explored in the limit of low dipole-energy (semi-linear), from which is derived a physical parameter characterizing separative magnetization transport (SMT). It is shown that the necessary and sufficient condition for SMT to occur is that the parameter is spatially inhomogeneous. Third, the high spin-temperature (linear) limit is shown to be equivalent to the model of nuclear spin transport of Genack and Redfield. Differences among the three forms of the model are illustrated by numerical solution with parameters corresponding to a magnetic resonance force microscopy (MRFM) experiment. A family of analytic, steady-state solutions to the nonlinear equation is derived and shown to be the spin-temperature analog of the Langevin paramagnetic equation and Curie's law. Finally, we analyze the separative quality of magnetization transport, and a steady-state solution for the magnetization is shown to be compatible with Fenske's separative mass transport equation.
Linear optimization Linear programming using the Simplex method
McCready, Mark J.
Linear optimization Linear programming using the Simplex method Maximize M = 40 x1 + 60 x2 subject, that increasing x2 is the way to get the biggest impact. The idea of the simplex method is to move only
Kerns, J.A.; Stone, R.R.; Fabyan, J.
1985-02-12T23:59:59.000Z
A magnetically-conductive filler material bridges the gap between a multi-part magnetic shield structure which substantially encloses a predetermined volume so as to minimize the ingress or egress of magnetic fields with respect to that volume. The filler material includes a heavy concentration of single-magnetic-domain-sized particles of a magnetically conductive material (e.g. soft iron, carbon steel or the like) dispersed throughout a carrier material which is generally a non-magnetic material that is at least sometimes in a plastic or liquid state. The maximum cross-sectional particle dimension is substantially less than the nominal dimension of the gap to be filled. An epoxy base material (i.e. without any hardening additive) low volatility vacuum greases or the like may be used for the carrier material. The structure is preferably exposed to the expected ambient field while the carrier is in a plastic or liquid state so as to facilitate alignment of the single-magnetic-domain-sized particles with the expected magnetic field lines.
Matsui, Hiroshi (Glen Rock, NJ); Matsunaga, Tadashi (Tokyo, JP)
2010-11-16T23:59:59.000Z
A magnetic nanotube includes bacterial magnetic nanocrystals contacted onto a nanotube which absorbs the nanocrystals. The nanocrystals are contacted on at least one surface of the nanotube. A method of fabricating a magnetic nanotube includes synthesizing the bacterial magnetic nanocrystals, which have an outer layer of proteins. A nanotube provided is capable of absorbing the nanocrystals and contacting the nanotube with the nanocrystals. The nanotube is preferably a peptide bolaamphiphile. A nanotube solution and a nanocrystal solution including a buffer and a concentration of nanocrystals are mixed. The concentration of nanocrystals is optimized, resulting in a nanocrystal to nanotube ratio for which bacterial magnetic nanocrystals are immobilized on at least one surface of the nanotubes. The ratio controls whether the nanocrystals bind only to the interior or to the exterior surfaces of the nanotubes. Uses include cell manipulation and separation, biological assay, enzyme recovery, and biosensors.
Structure based chemical shift prediction using Random Forests non-linear regression
Langmead, Christopher James
Structure based chemical shift prediction using Random Forests non-linear regression K. Arun-ordinates will permit close study of this relationship. This paper presents a novel non-linear regression based ap, regression, Random Forests #12;Abstract Protein nuclear magnetic resonance (NMR) chemical shifts are among
NUMERICAL SOLUTION OF A TRANSIENT NON-LINEAR AXISYMMETRIC EDDY CURRENT MODEL WITH NON-LOCAL
RodrÃguez, Rodolfo
NUMERICAL SOLUTION OF A TRANSIENT NON-LINEAR AXISYMMETRIC EDDY CURRENT MODEL WITH NON@ing-mat.udec.cl This paper deals with an axisymmetric transient eddy current problem in conductive nonlinear magnetic media of the proposed scheme. Keywords: transient eddy current problem; electromagnetic losses; nonlinear magnetic
Park, Joung Won
2010-10-12T23:59:59.000Z
In this work, a highly linear broadband Low Noise Amplifier (LNA) is presented. The linearity issue in broadband Radio Frequency (RF) front-end is introduced, followed by an analysis of the specifications and requirements of a broadband LNA through...
Magnets & Magnet Condensed Matter Science
McQuade, D. Tyler
18 No. 1 CONDENSED MATTER SCIENCE Technique development, graphene, magnetism & magnetic materials Pressure 9 Metal to Insulator Transition on the N=0 Landau Level in Graphene 10 Evidence for Fractional Quantum Hall States in Suspended Bilayer and Trilayer Graphene 11 Fractional Quantum Hall Effect
Wave functions of linear systems
Tomasz Sowinski
2007-06-05T23:59:59.000Z
Complete analysis of quantum wave functions of linear systems in an arbitrary number of dimensions is given. It is shown how one can construct a complete set of stationary quantum states of an arbitrary linear system from purely classical arguments. This construction is possible because for linear systems classical dynamics carries the whole information about quantum dynamics.
Special set linear algebra and special set fuzzy linear algebra
W. B. Vasantha Kandasamy; Florentin Smarandache; K. Ilanthenral
2009-12-30T23:59:59.000Z
The authors in this book introduce the notion of special set linear algebra and special set fuzzy Linear algebra, which is an extension of the notion set linear algebra and set fuzzy linear algebra. These concepts are best suited in the application of multi expert models and cryptology. This book has five chapters. In chapter one the basic concepts about set linear algebra is given in order to make this book a self contained one. The notion of special set linear algebra and their fuzzy analogue is introduced in chapter two. In chapter three the notion of special set semigroup linear algebra is introduced. The concept of special set n-vector spaces, n greater than or equal to three is defined and their fuzzy analogue is their fuzzy analogue is given in chapter four. The probable applications are also mentioned. The final chapter suggests 66 problems.
High force density linear permanent magnet motors : "electromagnetic muscle actuators"
Ruddy, Bryan P. (Bryan Paul), 1983-
2012-01-01T23:59:59.000Z
Actuator performance represents a key constraint on the capability of many engineered devices. Performance of these devices is often exceeded by their muscle-powered natural counterparts, inspiring the development of new, ...
Optimization of a dual acting, magnetically driven, linear actuator
Willerton, Justin Ryan
2002-01-01T23:59:59.000Z
will be found. Once complete, a different approach in meeting the design objectives of a stroke length of at least 10 mils, a low maximum coil temperature and a low actuator weight, will be taken. Instead of optimizing the geometry, the rubber pads...
Kjall, Jonas Alexander
2012-01-01T23:59:59.000Z
Magnetism in Ultracold Gases 4 Magnetic phase diagram of aMagnetism . . . . . . . . . . . .1.3 Magnetism in condensedIntroduction 1 Brief introduction to magnetism 1.1 Classic
Controlling Magnetism at the Nanoscale
Wong, Jared
2012-01-01T23:59:59.000Z
Manipulation of Magnetism - External148 Conclusion A The Magnetism Cheat Sheet A.1 Magnetic157 A.2 Magnetism Unit Conversion
Laminated grid and web magnetic cores
Sefko, John (Monroeville, PA); Pavlik, Norman M. (Plum Borough, PA)
1984-01-01T23:59:59.000Z
A laminated magnetic core characterized by an electromagnetic core having core legs which comprise elongated apertures and edge notches disposed transversely to the longitudinal axis of the legs, such as high reluctance cores with linear magnetization characteristics for high voltage shunt reactors. In one embodiment the apertures include compact bodies of microlaminations for more flexibility and control in adjusting permeability and/or core reluctance.
Positrons for linear colliders
Ecklund, S.
1987-11-01T23:59:59.000Z
The requirements of a positron source for a linear collider are briefly reviewed, followed by methods of positron production and production of photons by electromagnetic cascade showers. Cross sections for the electromagnetic cascade shower processes of positron-electron pair production and Compton scattering are compared. A program used for Monte Carlo analysis of electromagnetic cascades is briefly discussed, and positron distributions obtained from several runs of the program are discussed. Photons from synchrotron radiation and from channeling are also mentioned briefly, as well as positron collection, transverse focusing techniques, and longitudinal capture. Computer ray tracing is then briefly discussed, followed by space-charge effects and thermal heating and stress due to showers. (LEW)
Harrison, S. E.; Huo, Y.; Harris, J. S. [Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Collins-McIntyre, L. J.; Hesjedal, T., E-mail: Thorsten.Hesjedal@physics.ox.ac.uk [Department of Physics, Clarendon Laboratory, University of Oxford, Oxford OX1 3PU (United Kingdom); Li, S. [Department of Physics, Stanford University, Stanford, California 94305 (United States); Baker, A. A. [Department of Physics, Clarendon Laboratory, University of Oxford, Oxford OX1 3PU (United Kingdom); Magnetic Spectroscopy Group, Diamond Light Source, Didcot, Oxfordshire OX11 0DE (United Kingdom); Shelford, L. R.; Laan, G. van der [Magnetic Spectroscopy Group, Diamond Light Source, Didcot, Oxfordshire OX11 0DE (United Kingdom); Pushp, A.; Parkin, S. S. P. [IBM Almaden Research Center, 650 Harry Road, San Jose, California 95120 (United States); Arenholz, E. [Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
2014-01-14T23:59:59.000Z
Incorporation of magnetic dopants into topological insulators to break time-reversal symmetry is a prerequisite for observing the quantum anomalous Hall (QAHE) effect and other novel magnetoelectric phenomena. GdBiTe{sub 3} with a Gd:Bi ratio of 1:1 is a proposed QAHE system, however, the reported solubility limit for Gd doping into Bi{sub 2}Te{sub 3} bulk crystals is between ?0.01 and 0.05. We present a magnetic study of molecular beam epitaxy grown (Gd{sub x}Bi{sub 1–x}){sub 2}Te{sub 3} thin films with a high Gd concentration, up to x ? 0.3. Magnetometry reveals that the films are paramagnetic down to 1.5?K. X-ray magnetic circular dichroism at the Gd M{sub 4,5} edge at 1.5?K reveals a saturation field of ?6?T, and a slow decay of the magnetic moment with temperature up to 200?K. The Gd{sup 3+} ions, which are substitutional on Bi sites in the Bi{sub 2}Te{sub 3} lattice, exhibit a large atomic moment of ?7??{sub B}, as determined by bulk-sensitive superconducting quantum interference device magnetometry. Surface oxidation and the formation of Gd{sub 2}O{sub 3} lead to a reduced moment of ?4??{sub B} as determined by surface-sensitive x-ray magnetic circular dichroism. Their large atomic moment makes these films suitable for incorporation into heterostructures, where interface polarization effects can lead to the formation of magnetic order within the topological insulators.
Spin noise spectroscopy beyond thermal equilibrium and linear response
P. Glasenapp; Luyi Yang; D. Roy; D. G. Rickel; A. Greilich; M. Bayer; N. A. Sinitsyn; S. A. Crooker
2014-07-10T23:59:59.000Z
Per the fluctuation-dissipation theorem, the information obtained from spin fluctuation studies in thermal equilibrium is necessarily constrained by the system's linear response functions. However, by including weak radiofrequency magnetic fields, we demonstrate that intrinsic and random spin fluctuations even in strictly unpolarized ensembles \\emph{can} reveal underlying patterns of correlation and coupling beyond linear response, and can be used to study non-equilibrium and even multiphoton coherent spin phenomena. We demonstrate this capability in a classical vapor of $^{41}$K alkali atoms, where spin fluctuations alone directly reveal Rabi splittings, the formation of Mollow triplets and Autler-Townes doublets, ac Zeeman shifts, and even nonlinear multiphoton coherences.
Linear and nonlinear wave propagation in weakly relativistic quantum plasmas
Stefan, Martin; Brodin, Gert [Department of Physics, Umea University, SE-901 87 Umea (Sweden)
2013-01-15T23:59:59.000Z
We consider a recently derived kinetic model for weakly relativistic quantum plasmas. We find that that the effects of spin-orbit interaction and Thomas precession may alter the linear dispersion relation for a magnetized plasma in case of high plasma densities and/or strong magnetic fields. Furthermore, the ponderomotive force induced by an electromagnetic pulse is studied for an unmagnetized plasma. It turns out that for this case the spin-orbit interaction always gives a significant contribution to the quantum part of the ponderomotive force.
Neutrino magnetic moment in a magnetized plasma
N. V. Mikheev; E. N. Narynskaya
2010-11-08T23:59:59.000Z
The contribution of a magnetized plasma to the neutrino magnetic moment is calculated. It is shown that only part of the additional neutrino energy in magnetized plasma connecting with its spin and magnetic field strength defines the neutrino magnetic moment. It is found that the presence of magnetized plasma does not lead to the considerable increase of the neutrino magnetic moment in contrast to the results presented in literature previously.
6, 66276694, 2006 linearized ozone
Boyer, Edmond
ACPD 6, 66276694, 2006 CHEM2D-OPP linearized ozone photochemistry J. P. McCormack et al. Title Chemistry and Physics Discussions CHEM2D-OPP: A new linearized gas-phase ozone photochemistry.mccormack@nrl.navy.mil) 6627 #12;ACPD 6, 66276694, 2006 CHEM2D-OPP linearized ozone photochemistry J. P. McCormack et al
Petroglyphs, Lighting, and Magnetism
Walker, Merle F
2007-01-01T23:59:59.000Z
1950 Electricity and Magnetism: Theory and Applications.I Petroglyphs, Lightning, and Magnetism | Walker Figure 8.I Petroglyphs, Lightning, and Magnetism | Walker Figure IL
Quantization of general linear electrodynamics
Rivera, Sergio; Schuller, Frederic P. [Albert Einstein Institute, Max Planck Institute for Gravitational Physics, Am Muehlenberg 1, 14476 Potsdam (Germany)
2011-03-15T23:59:59.000Z
General linear electrodynamics allow for an arbitrary linear constitutive relation between the field strength 2-form and induction 2-form density if crucial hyperbolicity and energy conditions are satisfied, which render the theory predictive and physically interpretable. Taking into account the higher-order polynomial dispersion relation and associated causal structure of general linear electrodynamics, we carefully develop its Hamiltonian formulation from first principles. Canonical quantization of the resulting constrained system then results in a quantum vacuum which is sensitive to the constitutive tensor of the classical theory. As an application we calculate the Casimir effect in a birefringent linear optical medium.
Identifying Redundant Linear Constraints in Systems of Linear ...
2006-06-22T23:59:59.000Z
Jun 22, 2006 ... redundant linear constraints from the system (2.1) and (2.2). ... It is informative to note that in the above theorem, the optimal ..... S. Boyd and L. El Ghaoui, “Linear Matrix Inequalities in System and Control Theory”, SIAM, vol.
Linear Algebra 1: Computing canonical forms in exact linear
Pernet, Clément
Linear Algebra 1: Computing canonical forms in exact linear algebra Clément PERNET, LIG, where U is invertible Reduced echelon form: E = 1 0 0 1 0 1 Gauss-Jordan elimination #12 a field: B = U-1 AU Frobenius normal form (or canonical rational form): F = CP0 CP1 ... CPk
Radio-frequency quadrupole resonator for linear accelerator
Moretti, A.
1982-10-19T23:59:59.000Z
An RFQ resonator for a linear accelerator having a reduced level of interfering modes and producing a quadrupole mode for focusing, bunching and accelerating beams of heavy charged particles, with the construction being characterized by four elongated resonating rods within a cylinder with the rods being alternately shorted and open electrically to the shell at common ends of the rods to provide an LC parallel resonant circuit when activated by a magnetic field transverse to the longitudinal axis.
Baryon magnetic moments in the background field method
Lee, F X; Zhou, L; Wilcox, W
2005-01-01T23:59:59.000Z
We present a calculation of the magnetic moments for the baryon octet and decuplet using the background-field method and standard Wilson gauge and fermion actions in the quenched approximation of lattice QCD. Progressively smaller static magnetic fields are introduced on a $24^4$ lattice at beta=6.0 and the pion mass is probed down to about 500 MeV. Magnetic moments are extracted from the linear response of the masses to the background field.
Baryon magnetic moments in the external field method
Lee, F X; Zhou, L; Wilcox, W
2005-01-01T23:59:59.000Z
We present a calculation of the magnetic moments of the baryon octet and decuplet using the external field method and standard Wilson gauge and fermion actions in the quenched approximation. Progressively smaller static magnetic fields are introduced on a $24^4$ latticeat beta=6.0 and the pion mass is probed down to about 500 MeV. Magnetic moments are extracted from the linear response of the masses to the external field.
Magnetic Catalysis vs Magnetic Inhibition
Kenji Fukushima; Yoshimasa Hidaka
2012-09-06T23:59:59.000Z
We discuss the fate of chiral symmetry in an extremely strong magnetic field B. We investigate not only quark fluctuations but also neutral meson effects. The former would enhance the chiral-symmetry breaking at finite B according to the Magnetic Catalysis, while the latter would suppress the chiral condensate once B exceeds the scale of the hadron structure. Using a chiral model we demonstrate how neutral mesons are subject to the dimensional reduction and the low dimensionality favors the chiral-symmetric phase. We point out that this effect, the Magnetic Inhibition, can be a feasible explanation for recent lattice-QCD data indicating the decreasing behavior of the chiral-restoration temperature with increasing B.
Superconducting Magnet Division
Superconducting Magnet Division DOE NP Program Review - July 06 1 Brookhaven Magnet Division - Nuclear Physics Program Support Activities Superconducting Magnet Program RHIC Operations Support Spin Summary Peter Wanderer, DOE review, July 25, 2006 Acting Head, Superconducting Magnet Division #12
Astrophysical Gyrokinetics: Basic Equations and Linear Theory
Gregory G. Howes; Steven C. Cowley; William Dorland; Gregory W. Hammett; Eliot Quataert; Alexander A. Schekochihin
2006-05-04T23:59:59.000Z
Magnetohydrodynamic (MHD) turbulence is encountered in a wide variety of astrophysical plasmas, including accretion disks, the solar wind, and the interstellar and intracluster medium. On small scales, this turbulence is often expected to consist of highly anisotropic fluctuations with frequencies small compared to the ion cyclotron frequency. For a number of applications, the small scales are also collisionless, so a kinetic treatment of the turbulence is necessary. We show that this anisotropic turbulence is well described by a low frequency expansion of the kinetic theory called gyrokinetics. This paper is the first in a series to examine turbulent astrophysical plasmas in the gyrokinetic limit. We derive and explain the nonlinear gyrokinetic equations and explore the linear properties of gyrokinetics as a prelude to nonlinear simulations. The linear dispersion relation for gyrokinetics is obtained and its solutions are compared to those of hot-plasma kinetic theory. These results are used to validate the performance of the gyrokinetic simulation code {\\tt GS2} in the parameter regimes relevant for astrophysical plasmas. New results on global energy conservation in gyrokinetics are also derived. We briefly outline several of the problems to be addressed by future nonlinear simulations, including particle heating by turbulence in hot accretion flows and in the solar wind, the magnetic and electric field power spectra in the solar wind, and the origin of small-scale density fluctuations in the interstellar medium.
Linear diffusion into a Faraday cage.
Warne, Larry Kevin; Lin, Yau Tang; Merewether, Kimball O.; Chen, Kenneth C.
2011-11-01T23:59:59.000Z
Linear lightning diffusion into a Faraday cage is studied. An early-time integral valid for large ratios of enclosure size to enclosure thickness and small relative permeability ({mu}/{mu}{sub 0} {le} 10) is used for this study. Existing solutions for nearby lightning impulse responses of electrically thick-wall enclosures are refined and extended to calculate the nearby lightning magnetic field (H) and time-derivative magnetic field (HDOT) inside enclosures of varying thickness caused by a decaying exponential excitation. For a direct strike scenario, the early-time integral for a worst-case line source outside the enclosure caused by an impulse is simplified and numerically integrated to give the interior H and HDOT at the location closest to the source as well as a function of distance from the source. H and HDOT enclosure response functions for decaying exponentials are considered for an enclosure wall of any thickness. Simple formulas are derived to provide a description of enclosure interior H and HDOT as well. Direct strike voltage and current bounds for a single-turn optimally-coupled loop for all three waveforms are also given.
Extreme hydrogen plasma densities achieved in a linear plasma generator
Rooij, G. J. van; Veremiyenko, V. P.; Goedheer, W. J.; de Groot, B.; Kleyn, A. W.; Smeets, P. H. M.; Versloot, T. W.; Whyte, D. G.; Engeln, R.; Schram, D. C.; Cardozo, N. J. Lopes [FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, Trilateral Euregio Cluster, Nieuwegein, Uthrecht 3430BE (Netherlands); Massachusetts Institute of Technology, Cambridge, Massachusetts 02139-4307 (United States); FOM-Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM, Trilateral Euregio Cluster, Nieuwegein, Uthrecht 3430BE (NL) and Eindhoven University of Technology, 5600 MB Eindhoven (Netherlands)
2007-03-19T23:59:59.000Z
A magnetized hydrogen plasma beam was generated with a cascaded arc, expanding in a vacuum vessel at an axial magnetic field of up to 1.6 T. Its characteristics were measured at a distance of 4 cm from the nozzle: up to a 2 cm beam diameter, 7.5x10{sup 20} m{sup -3} electron density, {approx}2 eV electron and ion temperatures, and 3.5 km/s axial plasma velocity. This gives a 2.6x10{sup 24} H{sup +} m{sup -2} s{sup -1} peak ion flux density, which is unprecedented in linear plasma generators. The high efficiency of the source is obtained by the combined action of the magnetic field and an optimized nozzle geometry. This is interpreted as a cross-field return current that leads to power dissipation in the beam just outside the source.
Li, Shufa; Gao, Ruixin; Cheng, Chuyuan; Yan, Yong; Lai, Tianshu, E-mail: stslts@mail.sysu.edu.cn [State-Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-Sen University, Guangzhou, Guangdong 510275 (China)] [State-Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-Sen University, Guangzhou, Guangdong 510275 (China)
2013-12-09T23:59:59.000Z
Ultrafast magnetization dynamics in GdFeCo films triggered by femtosecond laser pulses with and without an external field applied is studied experimentally for different excitation fluence. It is found that subpicosecond magnetization reversal occurs simultaneously in the ultrafast dynamics of both saturation and remnant magnetization states and almost identical within 13 ps, whereas relatively slow magnetization reversal across compensation point appears only in the dynamics of saturation magnetization state. It shows the subpicosecond magnetization reversal is external field independent, and originates from intrinsic magnetic evolution in ferrimagnetic system. The intrinsic subpicosecond reversal is qualitatively explained by linear reversal.
Chintala, Rohit
2012-10-19T23:59:59.000Z
of the transfer function from the road disturbance to the actuating effort with the change in the sprung mass of the quarter-car system. The quarter-car system makes use of a linear brushless permanent magnet motor (LBPMM) as an actuator, a linear variable...
Masaaki Yamada, Russell Kulsrud and Hantao Ji
2009-09-17T23:59:59.000Z
We review the fundamental physics of magnetic reconnection in laboratory and space plasmas, by discussing results from theory, numerical simulations, observations from space satellites, and the recent results from laboratory plasma experiments. After a brief review of the well-known early work, we discuss representative recent experimental and theoretical work and attempt to interpret the essence of significant modern findings. In the area of local reconnection physics, many significant findings have been made with regard to two- uid physics and are related to the cause of fast reconnection. Profiles of the neutral sheet, Hall currents, and the effects of guide field, collisions, and micro-turbulence are discussed to understand the fundamental processes in a local reconnection layer both in space and laboratory plasmas. While the understanding of the global reconnection dynamics is less developed, notable findings have been made on this issue through detailed documentation of magnetic self-organization phenomena in fusion plasmas. Application of magnetic reconnection physics to astrophysical plasmas is also brie y discussed.
Patterned Magnetic Nanostructures and Quantized Magnetic Disks
-increasing demands in data storage and to new applications of magnetic devices in the field of sensors. NewPatterned Magnetic Nanostructures and Quantized Magnetic Disks STEPHEN Y. CHOU Invited Paper, opens up new opportunities for engineering innovative magnetic materials and devices, developing ultra
An optimized magnet for magnetic refrigeration
Bjørk, R; Smith, A; Christensen, D V; Pryds, N
2014-01-01T23:59:59.000Z
A magnet designed for use in a magnetic refrigeration device is presented. The magnet is designed by applying two general schemes for improving a magnet design to a concentric Halbach cylinder magnet design and dimensioning and segmenting this design in an optimum way followed by the construction of the actual magnet. The final design generates a peak value of 1.24 T, an average flux density of 0.9 T in a volume of 2 L using only 7.3 L of magnet, and has an average low flux density of 0.08 T also in a 2 L volume. The working point of all the permanent magnet blocks in the design is very close to the maximum energy density. The final design is characterized in terms of a performance parameter, and it is shown that it is one of the best performing magnet designs published for magnetic refrigeration.
Magnetic positioner having a single moving part
Trumper, David L. (Plaistow, NH); Kim, Won-Jong (Cambridge, MA)
1999-01-01T23:59:59.000Z
A magnetic positioner is provided which is capable of providing long travel in two dimension and short travel in the remaining four dimensions. The positioner has a movable stage and a stator oriented adjacent and substantially parallel to this stage. At least three sets of first magnetic elements, which for preferred embodiments are winding sets capable of generating forces in two directions, are on the portion of the stator adjacent to the stage at any given time, and at least two second magnetic elements, which are magnet arrays for the preferred embodiment, are on the stage adjacent to the stator. At least one of the second magnetic elements overlaps multiple first magnetic elements for all positions of the stage relative to the stator, with one magnet overlapping multiple windings for one preferred embodiment of the invention and two magnets on the stage overlapping multiple windings on the stator for a second embodiment. The windings form a linear motor providing forces in both a corresponding long travel dimension and in a dimension perpendicular to both long travel dimensions.
Simulations of magnetic nanoparticle Brownian motion
Daniel B Reeves; John B Weaver
2014-03-25T23:59:59.000Z
Magnetic nanoparticles are useful in many medical applications because they interact with biology on a cellular level thus allowing microenvironmental investigation. An enhanced understanding of the dynamics of magnetic particles may lead to advances in imaging directly in magnetic particle imaging (MPI) or through enhanced MRI contrast and is essential for nanoparticle sensing as in magnetic spectroscopy of Brownian motion (MSB). Moreover, therapeutic techniques like hyperthermia require information about particle dynamics for effective, safe, and reliable use in the clinic. To that end, we have developed and validated a stochastic dynamical model of rotating Brownian nanoparticles from a Langevin equation approach. With no field, the relaxation time toward equilibrium matches Einstein's model of Brownian motion. In a static field, the equilibrium magnetization agrees with the Langevin function. For high frequency or low amplitude driving fields, behavior characteristic of the linearized Debye approximation is reproduced. In a higher field regime where magnetic saturation occurs, the magnetization and its harmonics compare well with the effective field model. On another level, the model has been benchmarked against experimental results, successfully demonstrating that harmonics of the magnetization carry enough information to infer environmental parameters like viscosity and temperature.
Including stereoscopic information in the reconstruction of coronal magnetic fields
T. Wiegelmann; T. Neukirch
2008-01-23T23:59:59.000Z
We present a method to include stereoscopic information about the three dimensional structure of flux tubes into the reconstruction of the coronal magnetic field. Due to the low plasma beta in the corona we can assume a force free magnetic field, with the current density parallel to the magnetic field lines. Here we use linear force free fields for simplicity. The method uses the line of sight magnetic field on the photosphere as observational input. The value of $\\alpha$ is determined iteratively by comparing the reconstructed magnetic field with the observed structures. The final configuration is the optimal linear force solution constrained by both the photospheric magnetogram and the observed plasma structures. As an example we apply our method to SOHO MDI/EIT data of an active region. In the future it is planned to apply the method to analyse data from the SECCHI instrument aboard the STEREO mission.
The origin, evolution and signatures of primordial magnetic fields
Subramanian, Kandaswamy
2015-01-01T23:59:59.000Z
The universe is magnetized on all scales probed so far. On the largest scales, galaxies and galaxy clusters host magnetic fields at the micro Gauss level coherent on scales up to ten kpc. Recent observational evidence suggests that even the intergalactic medium in voids could host a weak $\\sim 10^{-16}$ Gauss magnetic field, coherent on Mpc scales. An intriguing possibility is that these observed magnetic fields are a relic from the early universe, albeit one which has been subsequently amplified and maintained by a dynamo in collapsed objects. We review here the origin, evolution and signatures of primordial magnetic fields. After a brief summary of magnetohydrodynamics in the expanding universe, we turn to magnetic field generation during inflation and other phase transitions. We trace the linear and nonlinear evolution of the generated primordial fields through the radiation era, including viscous effects. Sensitive observational signatures of primordial magnetic fields on the cosmic microwave background, ...
Application of linear response theory to magnetotransport properties of dense plasmas
Adams, J. R.; Redmer, R. [Institut fuer Physik, Universitaet Rostock, D-18051 Rostock (Germany); Reinholz, H. [Institut fuer Physik, Universitaet Rostock, D-18051 Rostock (Germany); Institut fuer Theoretische Physik, Johannes-Kepler-Universitaet Linz, 4040 Linz (Austria)
2010-03-15T23:59:59.000Z
Linear response theory, as developed within the Zubarev formalism, is a quantum statistical approach for describing systems out of but close to equilibrium, which has been successfully applied to a wide variety of plasmas in an external electric field and/or containing a temperature gradient. We present here an extension of linear response theory to include the effects of an external magnetic field. General expressions for the complete set of relevant transport properties are given. In particular, the Hall effect and the influence of a magnetic field on the dc electrical conductivity are discussed. Low-density limits including electron-electron scattering are presented as well as results for arbitrary degeneracy.
Estimation of Saturation of Permanent-Magnet Synchronous Motors Through an Energy-Based Model
Jebai, AlKassem; Martin, Philippe; Rouchon, Pierre
2011-01-01T23:59:59.000Z
We propose a parametric model of the saturated Permanent-Magnet Synchronous Motor (PMSM) together with an estimation method of the magnetic parameters. The model is based on an energy function which simply encompasses the saturation effects. Injection of fast-varying pulsating voltages and measurements of the resulting current ripples then permit to identify the magnetic parameters by linear least squares. Experimental results on a surface-mounted PMSM and an interoir magnet PMSM illustrate the relevance of the approach.
Superconducting Magnet Division
Gupta, Ramesh
Superconducting Magnet Division Permanent Magnet Designs with Large Variations in Field Strength the residual field of the magnetized bricks by concentrating flux lines at the iron pole. Low Field Design Medium Field Design Superconducting Magnet Division Dipole and Quadrupole Magnets for RHIC e
Algorithms for Symmetric Linear and Integer Programs
Bödi, Richard; Joswig, Michael
2010-01-01T23:59:59.000Z
This paper deals with exploiting symmetry for solving linear and integer programming problems. Basic properties of linear representations of finite groups can be used to reduce symmetric linear programming to solving linear programs of lower dimension. Combining this approach with knowledge of the geometry of feasible integer solutions yields an algorithm for solving highly symmetric integer linear programs which only takes time which is linear in the number of constraints and quadratic in the dimension.
Satti, John A. (Naperville, IL)
1980-01-01T23:59:59.000Z
A superconducting magnet designed to produce magnetic flux densities of the order of 4 to 5 Webers per square meter is constructed by first forming a cable of a plurality of matrixed superconductor wires with each wire of the plurality insulated from each other one. The cable is shaped into a rectangular cross-section and is wound with tape in an open spiral to create cooling channels. Coils are wound in a calculated pattern in saddle shapes to produce desired fields, such as dipoles, quadrupoles, and the like. Wedges are inserted between adjacent cables as needed to maintain substantially radial placement of the long dimensions of cross sections of the cables. After winding, individual strands in each of the cables are brought out to terminals and are interconnected to place all of the strands in series and to maximize the propagation of a quench by alternating conduction from an inner layer to an outer layer and from top half to bottom half as often as possible. Individual layers are separated from others by spiraled aluminum spacers to facilitate cooling. The wound coil is wrapped with an epoxy tape that is cured by heat and then machined to an interference fit with an outer aluminum pipe which is then affixed securely to the assembled coil by heating it to make a shrink fit. In an alternate embodiment, one wire of the cable is made of copper or the like to be heated externally to propagate a quench.
Charged relativistic fluids and non-linear electrodynamics
T. Dereli; R. W. Tucker
2010-01-08T23:59:59.000Z
The electromagnetic fields in Maxwell's theory satisfy linear equations in the classical vacuum. This is modified in classical non-linear electrodynamic theories. To date there has been little experimental evidence that any of these modified theories are tenable. However with the advent of high-intensity lasers and powerful laboratory magnetic fields this situation may be changing. We argue that an approach involving the self-consistent relativistic motion of a smooth fluid-like distribution of matter (composed of a large number of charged or neutral particles) in an electromagnetic field offers a viable theoretical framework in which to explore the experimental consequences of non-linear electrodynamics. We construct such a model based on the theory of Born and Infeld and suggest that a simple laboratory experiment involving the propagation of light in a static magnetic field could be used to place bounds on the fundamental coupling in that theory. Such a framework has many applications including a new description of the motion of particles in modern accelerators and plasmas as well as phenomena in astrophysical contexts such as in the environment of magnetars, quasars and gamma-ray bursts.
Non-linear Plasma Wake Growth of Electron Holes
Hutchinson, I H; Zhou, C
2015-01-01T23:59:59.000Z
An object's wake in a plasma with small Debye length that drifts \\emph{across} the magnetic field is subject to electrostatic electron instabilities. Such situations include, for example, the moon in the solar wind wake and probes in magnetized laboratory plasmas. The instability drive mechanism can equivalently be considered drift down the potential-energy gradient or drift up the density-gradient. The gradients arise because the plasma wake has a region of depressed density and electrostatic potential into which ions are attracted along the field. The non-linear consequences of the instability are analysed in this paper. At physical ratios of electron to ion mass, neither linear nor quasilinear treatment can explain the observation of large-amplitude perturbations that disrupt the ion streams well before they become ion-ion unstable. We show here, however, that electron holes, once formed, continue to grow, driven by the drift mechanism, and if they remain in the wake may reach a maximum non-linearly stable...
Linear conic optimization for nonlinear optimal control
Didier Henrion
2014-07-07T23:59:59.000Z
Jul 7, 2014 ... Abstract: Infinite-dimensional linear conic formulations are described for nonlinear optimal control problems. The primal linear problem consists ...
High-precision description and new properties of a spin-1 particle in a magnetic field
Alexander J. Silenko
2014-06-09T23:59:59.000Z
The exact Foldy-Wouthuysen Hamiltonian is derived for a pointlike spin-1 particle with a normal magnetic moment in a nonuniform magnetic field. For a uniform magnetic field, it is exactly separated into terms linear and quadratic in spin. New unexpected properties of a particle with an anomalous magnetic moment are found. Spin projections of a particle moving in a uniform magnetic field are not integer and the tensor polarization is asymmetric in the plane orthogonal to the field. Previously described spin-tensor effects caused by the tensor magnetic polarizability exist not only for nuclei but also for pointlike particles.
Nanostructured magnetic materials
Chan, Keith T.
2011-01-01T23:59:59.000Z
Magnetism and Magnetic Materials Conference, Atlanta, GA (Nanostructured Magnetic Materials by Keith T. Chan Doctor ofinduced by a Si-based material occurs at a Si/Ni interface
Interface Magnetism in Multiferroics
He, Qing
2011-01-01T23:59:59.000Z
1.2.1 Magnetism . . . . . . . . . . . . . . . . . . . 1.2.2domain walls . . . . . 3 Magnetism of domain walls in BiFeOof electrical control of magnetism in mixed phase BiFeO 3
Biholomorphic maps with linear parts having Jordan blocks: linearization and
Jordan block. Our main result proves convergence of the linearizing transformation of maps for which the Jordan part of the spectrum lies inside the unit circle and the spectrum satis#12;es a R in (C [x]) n , (1.2) where C [x] stands for the set of all formal power series with complex coe
High dimensional linear inverse modelling
Cooper, Fenwick C
2015-01-01T23:59:59.000Z
We introduce and demonstrate two linear inverse modelling methods for systems of stochastic ODE's with accuracy that is independent of the dimensionality (number of elements) of the state vector representing the system in question. Truncation of the state space is not required. Instead we rely on the principle that perturbations decay with distance or the fact that for many systems, the state of each data point is only determined at an instant by itself and its neighbours. We further show that all necessary calculations, as well as numerical integration of the resulting linear stochastic system, require computational time and memory proportional to the dimensionality of the state vector.
SUPERCONDUCTING MAGNETIC ENERGY STORAGE
Hassenzahl, W.
2011-01-01T23:59:59.000Z
Superconducting 30-MJ Energy Storage Coil", Proc. 19 80 ASC,Superconducting Magnetic Energy Storage Plant", IEEE Trans.SlIperconducting Magnetic Energy Storage Unit", in Advances
SUPERCONDUCTING MAGNETIC ENERGY STORAGE
Hassenzahl, W.
2011-01-01T23:59:59.000Z
Design of the BPA Superconducting 30-MJ Energy Storagefor a Utility Scale Superconducting Magnetic Energy Storagefor a Lnrge Scale Superconducting Magnetic Energy Storage
Linear electric field mass spectrometry
McComas, D.J.; Nordholt, J.E.
1992-12-01T23:59:59.000Z
A mass spectrometer and methods for mass spectrometry are described. The apparatus is compact and of low weight and has a low power requirement, making it suitable for use on a space satellite and as a portable detector for the presence of substances. High mass resolution measurements are made by timing ions moving through a gridless cylindrically symmetric linear electric field. 8 figs.
Linearized theory of peridynamic states.
Silling, Stewart Andrew
2009-04-01T23:59:59.000Z
A state-based peridynamic material model describes internal forces acting on a point in terms of the collective deformation of all the material within a neighborhood of the point. In this paper, the response of a state-based peridynamic material is investigated for a small deformation superposed on a large deformation. The appropriate notion of a small deformation restricts the relative displacement between points, but it does not involve the deformation gradient (which would be undefined on a crack). The material properties that govern the linearized material response are expressed in terms of a new quantity called the modulus state. This determines the force in each bond resulting from an incremental deformation of itself or of other bonds. Conditions are derived for a linearized material model to be elastic, objective, and to satisfy balance of angular momentum. If the material is elastic, then the modulus state is obtainable from the second Frechet derivative of the strain energy density function. The equation of equilibrium with a linearized material model is a linear Fredholm integral equation of the second kind. An analogue of Poincare's theorem is proved that applies to the infinite dimensional space of all peridynamic vector states, providing a condition similar to irrotationality in vector calculus.
PROCESS CONTROLLABILITY ANALYSIS USING LINEAR AND NONLINEAR
Skogestad, Sigurd
PROCESS CONTROLLABILITY ANALYSIS USING LINEAR AND NONLINEAR OPTIMISATION Samara D. Chenery October linear and nonlinear dynamic optimisation techniques. For the linear case an optimal control problem is formulated to assess the best achievable performance for the set of linear time invariant (LTI) controllers
Sikes, Derek S.
MATH F314-F71 Linear Algebra Summer 2014 Instructor: Dr. Dana E. Madison, demadison2@alaska is by email. Class Dates and Times: July 7 August 14, 12:00pm 1:50pm Textbook: Linear Algebra and its: This is a first course in linear algebra that starts with the basic objects vectors, matrices, systems of linear
Why quantum dynamics is linear
Thomas F. Jordan
2007-02-16T23:59:59.000Z
Quantum dynamics is linear. How do we know? From theory or experiment? The history of this question is reviewed. Nonlinear generalizations of quantum mechanics have been proposed. They predict small but clear nonlinear effects, which very accurate experiments have not seen. Is there a reason in principle why nonlinearity is not found? Is it impossible? Does quantum dynamics have to be linear? Attempts to prove this have not been decisive, because either their assumptions are not compelling or their arguments are not conclusive. The question has been left unsettled. There is a simple answer, based on a simple assumption. It was found in two steps separated by 44 years. They are steps back to simpler and more compelling assumptions. A proof of the assumptions of the Wigner-Bargmann proof has been known since 1962. It assumes that the maps of density matrices in time are linear. For this step, it is also assumed that density matrices are mapped one-to-one onto density matrices. An alternative is to assume that pure states are mapped one-to-one onto pure states and that entropy does not decrease. In a step taken in 2006, it is proved that the maps of density matrices in time are linear. It is assumed, as in the earlier step, that at each time the physical quantities and states are described by the usual linear structures of quantum mechanics, so the question is only about how things change in time. Beyond that, the proof assumes only that the dynamics does not depend on anything outside the system, but must allow the system to be described as part of a larger system.
Large Scale Approximate Inference and Experimental Design for Sparse Linear Models
Seeger, Matthias
Large Scale Approximate Inference and Experimental Design for Sparse Linear Models Matthias W.kyb.tuebingen.mpg.de/bs/people/seeger/ 27 June 2008 Matthias W. Seeger (MPI BioCyb) Large Scale Bayesian Experimental Design 27/6/08 1 / 27 Algorithms 4 Magnetic Resonance Imaging Sequences Matthias W. Seeger (MPI BioCyb) Large Scale Bayesian
Laced permanent magnet quadrupole drift tube magnets
Feinberg, B.; Behrsing, G.U.; Halbach, K.; Marks, J.S.; Morrison, M.E.; Nelson, D.H.
1988-10-01T23:59:59.000Z
A laced permanent magnet quadrupole drift tube magnet has been constructed for a proof-of-principle test. The magnet is a conventional tape-wound quadrupole electromagnet, using iron pole- pieces, with the addition of permanent magnet material (neodymium iron) between the poles to reduce the effects of saturation. The iron is preloaded with magnetic flux generated by the permanent magnet material, resulting in an asymmetrical saturation curve. Since the polarity of the quadrupole magnets in a drift tube linac is not reversed we can take advantage of this asymmetrical saturation to provide greater focusing strength. The magnet configuration has been optimized and the vanadium permendur poles needed in a conventional quadrupole have been replaced with iron poles. The use of permanent magnet material has allowed us to increase the focusing strength of the magnet by about 20% over that of a conventional tape-wound quadrupole. Comparisons will be made between this magnet and the conventional tape-wound quadrupole. 3 refs., 5 figs.
Set Linear Algebra and Set Fuzzy Linear Algebra
W. B. Vasantha Kandasamy; Florentin Smarandache; K. Ilanthenral
2008-06-17T23:59:59.000Z
In this book, the authors define the new notion of set vector spaces which is the most generalized form of vector spaces. Set vector spaces make use of the least number of algebraic operations, therefore, even a non-mathematician is comfortable working with it. It is with the passage of time, that we can think of set linear algebras as a paradigm shift from linear algebras. Here, the authors have also given the fuzzy parallels of these new classes of set linear algebras. This book is divided into seven chapters. The first chapter briefly recalls some of the basic concepts in order to make this book self-contained. Chapter two introduces the notion of set vector spaces which is the most generalized concept of vector spaces. Set vector spaces lends itself to define new classes of vector spaces like semigroup vector spaces and group vector spaces. These are also generalization of vector spaces. The fuzzy analogue of these concepts are given in Chapter three. In Chapter four, set vector spaces are generalized to biset bivector spaces and not set vector spaces. This is done taking into account the advanced information technology age in which we live. As mathematicians, we have to realize that our computer-dominated world needs special types of sets and algebraic structures. Set n-vector spaces and their generalizations are carried out in Chapter five. Fuzzy n-set vector spaces are introduced in the sixth chapter. The seventh chapter suggests more than three hundred problems.
Ferrofluid spin-up flows from uniform and non-uniform rotating magnetic fields
Khushrushahi, Shahriar Rohinton
2010-01-01T23:59:59.000Z
When ferrofluid in a cylindrical container is subjected to a rotating azimuthally directed magnetic field, the fluid "spins up" into an almost rigid-body rotation where ferrofluid nanoparticles have both a linear and an ...
Introduction Magnetic Anisotropy of
Rossak, Wilhelm R.
not completely understood interesting for dilute magnetic semiconductors (DMSs) transparent ferromagnets
Magnetic Imaging Wolfgang Kuch
Kuch, Wolfgang
Magnetic Imaging Wolfgang Kuch Freie UniversitÂ¨at Berlin, Institut fÂ¨ur Experimentalphysik, Arnimallee 14, 14195 Berlin, Germany kuch@physik.fu-berlin.de Abstract. Imaging of magnetic domains has- ern techniques is used nowadays routinely for magnetic imaging of magnetic ma- terials
Superconducting Magnet Division
McDonald, Kirk
Superconducting Magnet Division Ramesh Gupta 20T Target Solenoid with HTS Insert Solenoid Capture Laboratory New York, USA http://www.bnl.gov/magnets/staff/gupta #12;Superconducting Magnet Division Ramesh of HTS may significantly reduce the amount of Tungsten shielding Â· Summary #12;Superconducting Magnet
Closed loop control of the induction heating process using miniature magnetic sensors
Bentley, Anthony E.; Kelley, John Bruce; Zutavern, Fred J.
2003-05-20T23:59:59.000Z
A method and system for providing real-time, closed-loop control of the induction hardening process. A miniature magnetic sensor located near the outer surface of the workpiece measures changes in the surface magnetic field caused by changes in the magnetic properties of the workpiece as it heats up during induction heating (or cools down during quenching). A passive miniature magnetic sensor detects a distinct magnetic spike that appears when the saturation field, B.sub.sat, of the workpiece has been exceeded. This distinct magnetic spike disappears when the workpiece's surface temperature exceeds its Curie temperature, due to the sudden decrease in its magnetic permeability. Alternatively, an active magnetic sensor can measure changes in the resonance response of the monitor coil when the excitation coil is linearly swept over 0-10 MHz, due to changes in the magnetic permeability and electrical resistivity of the workpiece as its temperature increases (or decreases).
The magnetic shielding for the neutron decay spectrometer aSPECT
Gertrud Konrad; Fidel Ayala Guardia; Stefan Baeßler; Michael Borg; Ferenc Glück; Werner Heil; Stefan Hiebel; Raquel Munoz Horta; Yury Sobolev
2014-05-05T23:59:59.000Z
Many experiments in nuclear and neutron physics are confronted with the problem that they use a superconducting magnetic spectrometer which potentially affects other experiments by their stray magnetic field. The retardation spectrometer aSPECT consists, inter alia, of a superconducting magnet system that produces a strong longitudinal magnetic field of up to 6.2T. In order not to disturb other experiments in the vicinity of aSPECT, we had to develop a magnetic field return yoke for the magnet system. While the return yoke must reduce the stray magnetic field, the internal magnetic field and its homogeneity should not be affected. As in many cases, the magnetic shielding for aSPECT must manage with limited space. In addition, we must ensure that the additional magnetic forces on the magnet coils are not destructive. In order to determine the most suitable geometry for the magnetic shielding for aSPECT, we simulated a variety of possible geometries and combinations of shielding materials of non-linear permeability. The results of our simulations were checked through magnetic field measurements both with Hall and nuclear magnetic resonance probes. The experimental data are in good agreement with the simulated values: The mean deviation from the simulated exterior magnetic field is (-1.7+/-4.8)%. However, in the two critical regions, the internal magnetic field deviates by 0.2% respectively <1E-4 from the simulated values.
Large linear magnetoresistance in a GaAs/AlGaAs heterostructure
Aamir, Mohammed Ali, E-mail: aamir@physics.iisc.ernet.in; Goswami, Srijit, E-mail: aamir@physics.iisc.ernet.in; Ghosh, Arindam [Department of Physics, Indian Institute of Science, Bangalore 560 012 (India); Baenninger, Matthias; Farrer, Ian; Ritchie, David A. [Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom); Tripathi, Vikram [Department of Theoretical Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 (India); Pepper, Michael [Department of Electrical and Electronic Engineering, University College, London WC1E 7JE (United Kingdom)
2013-12-04T23:59:59.000Z
We report non-saturating linear magnetoresistance (MR) in a two-dimensional electron system (2DES) at a GaAs/AlGaAs heterointerface in the strongly insulating regime. We achieve this by driving the gate voltage below the pinch-off point of the device and operating it in the non-equilibrium regime with high source-drain bias. Remarkably, the magnitude of MR is as large as 500% per Tesla with respect to resistance at zero magnetic field, thus dwarfing most non-magnetic materials which exhibit this linearity. Its primary advantage over most other materials is that both linearity and the enormous magnitude are retained over a broad temperature range (0.3 K to 10 K), thus making it an attractive candidate for cryogenic sensor applications.
Linear-optical generation of eigenstates of the two-site XY model
Stefanie Barz; Borivoje Dakic; Yannick Ole Lipp; Frank Verstraete; James D. Whitfield; Philip Walther
2014-10-04T23:59:59.000Z
Much of the anticipation accompanying the development of a quantum computer relates to its application to simulating dynamics of another quantum system of interest. Here we study the building blocks for simulating quantum spin systems with linear optics. We experimentally generate the eigenstates of the XY Hamiltonian under an external magnetic field. The implemented quantum circuit consists of two CNOT gates, which are realized experimentally by harnessing entanglement from a photon source and by applying a CPhase gate. We tune the ratio of coupling constants and magnetic field by changing local parameters. This implementation of the XY model using linear quantum optics might open the door to the future studies of quenching dynamics using linear optics.
Optimal Constructions of Fault Tolerant Optical Linear Compressors and Linear Decompressors
Chang, Cheng-Shang
1 Optimal Constructions of Fault Tolerant Optical Linear Compressors and Linear Decompressors Cheng linear compressors and linear decompressors. The basic network element for our constructions is scaled first obtain a fundamental result on the minimum con- struction complexity of a linear compressor
Cast dielectric composite linear accelerator
Sanders, David M. (Livermore, CA); Sampayan, Stephen (Manteca, CA); Slenes, Kirk (Albuquerque, NM); Stoller, H. M. (Albuquerque, NM)
2009-11-10T23:59:59.000Z
A linear accelerator having cast dielectric composite layers integrally formed with conductor electrodes in a solventless fabrication process, with the cast dielectric composite preferably having a nanoparticle filler in an organic polymer such as a thermosetting resin. By incorporating this cast dielectric composite the dielectric constant of critical insulating layers of the transmission lines of the accelerator are increased while simultaneously maintaining high dielectric strengths for the accelerator.
Linearized supergravity from Matrix theory
D. Kabat; W. Taylor
1998-03-10T23:59:59.000Z
We show that the linearized supergravity potential between two objects arising from the exchange of quanta with zero longitudinal momentum is reproduced to all orders in 1/r by terms in the one-loop Matrix theory potential. The essential ingredient in the proof is the identification of the Matrix theory quantities corresponding to moments of the stress tensor and membrane current. We also point out that finite-N Matrix theory violates the equivalence principle.
Precision linear ramp function generator
Jatko, W. Bruce (Knoxville, TN); McNeilly, David R. (Maryville, TN); Thacker, Louis H. (Knoxville, TN)
1986-01-01T23:59:59.000Z
A ramp function generator is provided which produces a precise linear ramp unction which is repeatable and highly stable. A derivative feedback loop is used to stabilize the output of an integrator in the forward loop and control the ramp rate. The ramp may be started from a selected baseline voltage level and the desired ramp rate is selected by applying an appropriate constant voltage to the input of the integrator.
Precision linear ramp function generator
Jatko, W.B.; McNeilly, D.R.; Thacker, L.H.
1984-08-01T23:59:59.000Z
A ramp function generator is provided which produces a precise linear ramp function which is repeatable and highly stable. A derivative feedback loop is used to stabilize the output of an integrator in the forward loop and control the ramp rate. The ramp may be started from a selected baseline voltage level and the desired ramp rate is selected by applying an appropriate constant voltage to the input of the integrator.
Segmented rail linear induction motor
Cowan, M. Jr.; Marder, B.M.
1996-09-03T23:59:59.000Z
A segmented rail linear induction motor has a segmented rail consisting of a plurality of nonferrous electrically conductive segments aligned along a guideway. The motor further includes a carriage including at least one pair of opposed coils fastened to the carriage for moving the carriage. A power source applies an electric current to the coils to induce currents in the conductive surfaces to repel the coils from adjacent edges of the conductive surfaces. 6 figs.
Nanocomposite Magnets: Transformational Nanostructured Permanent Magnets
None
2010-10-01T23:59:59.000Z
Broad Funding Opportunity Announcement Project: GE is using nanomaterials technology to develop advanced magnets that contain fewer rare earth materials than their predecessors. Nanomaterials technology involves manipulating matter at the atomic or molecular scale, which can represent a stumbling block for magnets because it is difficult to create a finely grained magnet at that scale. GE is developing bulk magnets with finely tuned structures using iron-based mixtures that contain 80% less rare earth materials than traditional magnets, which will reduce their overall cost. These magnets will enable further commercialization of HEVs, EVs, and wind turbine generators while enhancing U.S. competitiveness in industries that heavily utilize these alternatives to rare earth minerals.
The influence of the magnetic field on the performance of an active magnetic regenerator (AMR)
Bjørk, R
2014-01-01T23:59:59.000Z
The influence of the time variation of the magnetic field, termed the magnetic field profile, on the performance of a magnetocaloric refrigeration device using the active magnetic regeneration (AMR) cycle is studied for a number of process parameters for both a parallel plate and packed bed regenerator using a numerical model. The cooling curve of the AMR is shown to be almost linear far from the Curie temperature of the magnetocaloric material. It is shown that a magnetic field profile that is 10% of the cycle time out of sync with the flow profile leads to a drop in both the maximum temperature span and the maximum cooling capacity of 20-40\\% for both parallel plate and packed bed regenerators. The maximum cooling capacity is shown to depend very weakly on the ramp rate of the magnetic field. Reducing the temporal width of the high field portion of the magnetic field profile by 10% leads to a drop in maximum temperature span and maximum cooling capacity of 5-20%. An increase of the magnetic field from 1 T t...
Byrne, J. M.; Telling, N. D.; Coker, V. S.; Pattrick, R. A. D.; Laan, G. van der; Arenholz, E.; Tuna, F.; Lloyd, J. R.
2011-08-02T23:59:59.000Z
The bioproduction of nano-scale magnetite by Fe(III)-reducing bacteria offers a potentially tunable, environmentally benign route to magnetic nanoparticle synthesis. Here, we demonstrate that it is possible to control the size of magnetite nanoparticles produced by Geobacter sulfurreducens, by adjusting the total biomass introduced at the start of the process. The particles have a narrow size distribution and can be controlled within the range of 10-50 nm. X-ray diffraction analysis indicates that controlled production of a number of different biominerals is possible via this method including goethite, magnetite and siderite, but their formation is strongly dependent upon the rate of Fe(III) reduction and total concentration and rate of Fe(II) produced by the bacteria during the reduction process. Relative cation distributions within the structure of the nanoparticles has been investigated by X-ray magnetic circular dichroism and indicates the presence of a highly reduced surface layer which is not observed when magnetite is produced through abiotic methods. The enhanced Fe(II)-rich surface, combined with small particle size, has important environmental applications such as in the reductive bioremediation of organics, radionuclides and metals. In the case of Cr(VI), as a model high-valence toxic metal, optimised biogenic magnetite is able to reduce and sequester the toxic hexavalent chromium very efficiently in the less harmful trivalent form.
Electronic and magnetic properties of iron doped zirconia: Theory and experiment
Debernardi, A., E-mail: alberto.debernardi@mdm.imm.cnr.it; Sangalli, D.; Lamperti, A.; Cianci, E. [Laboratorio MDM, IMM-CNR, 20864 Agrate Brianza (MB) (Italy); Lupo, P.; Casoli, F.; Albertini, F.; Nasi, L. [CNR-IMEM, Parco Area delle Scienze 37/A, 43124 Parma (Italy); Ciprian, R.; Torelli, P. [Laboratorio TASC, IOM-CNR, S.S. 14 km 163.5, Basovizza, I-34149 Trieste (Italy)
2014-05-07T23:59:59.000Z
We systematically investigated, both theoretically and experimentally, Zr{sub 1?x}Fe{sub x}O{sub 2?y} ranging from diluted (x???0.05) up to large (x???0.25) Fe concentration. By atomic layer deposition, we grew thin films of high-? zirconia in cubic phase with Fe uniformly distributed in the film, as proven by time of flight secondary ion mass spectrometry and transmission electron microscopy measurements. Iron is in Fe{sup 3+} oxidation state suggesting the formation of oxygen vacancies with y concentration close to x/2. By ab-initio simulations, we studied the phase diagram relating the stability of monoclinic vs. tetragonal phase as a function of Fe doping and film thickness: the critical thickness at which the pure zirconia is stabilized in the tetragonal phase is estimated ranging from 2 to 6?nm according to film morphology. Preliminary results by X-ray magnetic circular dichroism and alternating gradient force magnetometry are discussed in comparison to ab initio data enlightening the role of oxygen vacancies in the magnetic properties of the system.
Mueller, Fred M. (Los Alamos, NM); Bronisz, Lawrence (Los Alamos, NM); Grube, Holger (Los Alamos, NM); Nelson, David C. (Santa Fe, NM); Mace, Jonathan L. (Los Alamos, NM)
2006-11-14T23:59:59.000Z
A magnetic infrasound sensor is produced by constraining a permanent magnet inside a magnetic potential well above the surface of superconducting material. The magnetic infrasound sensor measures the position or movement of the permanent magnet within the magnetic potential well, and interprets the measurements. Infrasound sources can be located and characterized by combining the measurements from one or more infrasound sensors. The magnetic infrasound sensor can be tuned to match infrasound source types, resulting in better signal-to-noise ratio. The present invention can operate in frequency modulation mode to improve sensitivity and signal-to-noise ratio. In an alternate construction, the superconductor can be levitated over a magnet or magnets. The system can also be driven, so that time resolved perturbations are sensed, resulting in a frequency modulation version with improved sensitivity and signal-to-noise ratio.
Otani, Yoshichika
Controlled propagation of locally excited vortex dynamics in linear nanomagnet arrays This article. Here, we present a controlled propagation of locally excited magnetic vortex dynamics through a linear. Phys. D: Appl. Phys. 43 (2010) 335001 (7pp) doi:10.1088/0022-3727/43/33/335001 Controlled propagation
Magnet reliability in the Fermilab Main Injector and implications for the ILC
Tartaglia, M.A.; Blowers, J.; Capista, D.; Harding, D.J.; Kiemschies, O.; Rahimzadeh-Kalaleh, S.; Tompkins, J.C.; /Fermilab
2007-08-01T23:59:59.000Z
The International Linear Collider reference design requires over 13000 magnets, of approximately 135 styles, which must operate with very high reliability. The Fermilab Main Injector represents a modern machine with many conventional magnet styles, each of significant quantity, that has now accumulated many hundreds of magnet-years of operation. We review here the performance of the magnets built for this machine, assess their reliability and categorize the failure modes, and discuss implications for reliability of similar magnet styles expected to be used at the ILC.
D. B. Papadopoulos
2003-12-23T23:59:59.000Z
The equations which determine the response of a spinning charged particle moving in a uniform magnetic field to an incident gravitational wave are derived in the linearized approximation to general relativity. We verify that 1) the components of the 4-momentum, 4-velocity and the components of the spinning tensor, both electric and magnetic moments, exhibit resonances and 2) the co-existence of the uniform magnetic field and the GW are responsible for the resonances appearing in our equations. In the absence of the GW, the magnetic field and the components of the spin tensor decouple and the magnetic resonances disappear.
Cosmic Acceleration and Anisotropic models with Magnetic field
S. K. Tripathy; K. L. Mahanta
2014-12-10T23:59:59.000Z
Plane symmetric cosmological models are investigated with or without any dark energy components in the field equations. Keeping an eye on the recent observational constraints concerning the accelerating phase of expansion of the universe, the role of magnetic field is assessed. In the absence of dark energy components, magnetic field can favour an accelerating model even if we take a linear relationship between the directional Hubble parameters. In presence of dark energy components in the form of a time varying cosmological constant, the influence of magnetic field is found to be limited.
Linear-quadratic control problem with a linear term on semiinfinite ...
2003-12-18T23:59:59.000Z
Dec 15, 2003 ... We describe a complete solution of the linear-quadratic control prob- lem on a semiinfinite interval with the linear term in the objective func-.
High speed linear induction motor efficiency optimization
Johnson, Andrew P. (Andrew Peter)
2005-01-01T23:59:59.000Z
One of the reasons linear motors, a technology nearly a century old, have not been adopted for a large number of linear motion applications is that they have historically had poor efficiencies. This has restricted the ...
MANEUVER REGULATION, TRANSVERSE FEEDBACK LINEARIZATION, AND ZERO
Maggiore, Manfredi
MANEUVER REGULATION, TRANSVERSE FEEDBACK LINEARIZATION, AND ZERO DYNAMICS Chris Nielsen,1 Manfredi focus is on output maneuver regulation where stabilizing transverse dynamics is a key requirement. Keywords: Maneuver regulation, path following, feedback linearization, zero dynamics, non-square systems
Duality for Mixed-Integer Linear Programs
2007-04-05T23:59:59.000Z
The theory of duality for linear programs is well-developed and has been successful ... methods for determining the effect of modifications to the input data on the ..... and the primal problem is bounded, since linear programming duality tells us ...
SELF-SCHEDULED H1 CONTROLLERS FOR MAGNETIC BEARINGS Panagiotis Tsiotras
Tsiotras, Panagiotis
their very low power consumption (an order of magnitude lower than oil lm bear- ings) and their very long of magnetic bearings. Most of these techniques assume a linear time-invariant (LTI) plant. Such an assumption over a wide range, the linear time-invariant assumption may no longer be valid because the dynamics
Tamper resistant magnetic stripes
Naylor, Richard Brian (Albuquerque, NM); Sharp, Donald J. (Albuquerque, NM)
1999-01-01T23:59:59.000Z
This invention relates to a magnetic stripe comprising a medium in which magnetized particles are suspended and in which the encoded information is recorded by actual physical rotation or alignment of the previously magnetized particles within the flux reversals of the stripe which are 180.degree. opposed in their magnetic polarity. The magnetized particles are suspended in a medium which is solid, or physically rigid, at ambient temperatures but which at moderately elevated temperatures, such as 40.degree. C., is thinable to a viscosity permissive of rotation of the particles therein under applications of moderate external magnetic field strengths within acceptable time limits.
Collisionless magnetic reconnection in the presence of a sheared velocity field
Faganello, M. [Ecole Polytechnique, LPP, Palaiseau, 91128 (France); Pegoraro, F.; Califano, F. [Department of Physics, University of Pisa and CNISM, Pisa, 56127 (Italy); Marradi, L. [Department of Physics, University of Pisa and CNISM, Pisa, 56127 (Italy)] [Universite de Nice Sophia Antipolis, CNRS, Observatoire de la Cote d'Azur, 06304 Nice (France)
2010-06-15T23:59:59.000Z
The linear theory of magnetic field lines reconnection in a two-dimensional configuration in the presence of a (Kelvin-Helmholtz stable) sheared velocity field is investigated within a single fluid model, where the onset of magnetic field line reconnection is made possible by the effect of electron inertia in the so called large DELTA{sup '} regime.
Stochastic bridges of linear systems
Yongxin Chen; Tryphon Georgiou
2014-07-12T23:59:59.000Z
We study a generalization of the Brownian bridge as a stochastic process that models the position and velocity of inertial particles between the two end-points of a time interval. The particles experience random acceleration and are assumed to have known states at the boundary. Thus, the movement of the particles can be modeled as an Ornstein-Uhlenbeck process conditioned on position and velocity measurements at the two end-points. It is shown that optimal stochastic control provides a stochastic differential equation (SDE) that generates such a bridge as a degenerate diffusion process. Generalizations to higher order linear diffusions are considered.
Symmetries in Linear and Integer Programs
Bödi, R
2009-01-01T23:59:59.000Z
The notion of symmetry is defined in the context of Linear and Integer Programming. Symmetric linear and integer programs are studied from a group theoretical viewpoint. We show that for any linear program there exists an optimal solution in the fixed point set of its symmetry group. Using this result, we develop an algorithm that allows for reducing the dimension of any linear program having a non-trivial group of symmetries.
Linear Programming Lower Bounds for Minimum Converter ...
generation algorithm for solving the linear relaxation of the most promising ... Keywords: Optical Networks, Wavelength Assignment, Integer Programming.
Optimization Online - Vector Space Decomposition for Linear ...
Jean Bertrand Gauthier
2015-02-26T23:59:59.000Z
Feb 26, 2015 ... Abstract: This paper describes a vector space decomposition algorithmic framework for linear programming guided by dual feasibility ...
Varying-Coefficient Functional Linear Regression Models
Cardot, Hervé
Varying-Coefficient Functional Linear Regression Models Herv´e Cardot1 and Pascal Sarda2 1, the ability of such non linear functional approaches to produce competitive estimations. Short title : Varying monograph. We propose here another generalization of the functional linear regression model in which
Computational Reality XIII Non-linear regression
Berlin,Technische Universität
Computational Reality XIII Non-linear regression Inverse analysis II B. Emek Abali @ LKM - TU Berlin Abstract Linear regression to fit and determine parameters, shown in the last tutorial, is quite useful and widely implemented, however, there are material models where parameters are coupled non-linearly
(Parallel Linear Algebra Package) Jess Cmara Moreno
GimÃ©nez, Domingo
Ã¡lgebra lineal (Linear Algebra Objects). TambiÃ©n permite la utilizaciÃ³n de vistas (objetos referenciadosPLAPACK (Parallel Linear Algebra Package) JesÃºs CÃ¡mara Moreno ProgramaciÃ³n Paralela y ComputaciÃ³n ReducciÃ³n de Vectores InicializaciÃ³n de PLAPACK. Funciones. Templates. Funciones. Linear Algebra Objects
Entanglement of two-qubit photon beam by magnetic field
A. D. Levin; D. M. Gitman; R. C. Castro
2014-09-05T23:59:59.000Z
We have studied the possibility of affecting the entanglement measure of 2-qubit system consisting of two photons with different fixed frequencies but with two arbitrary linear polarizations, moving in the same direction, by the help of an applied external magnetic field. The interaction between the magnetic field and the photons in our model is achieved through intermediate electrons that interact with both the photons and the magnetic field. The possibility of exact theoretical analysis of this scheme is based on known exact solutions that describe the interaction of an electron subjected to an external magnetic field (or a medium of electrons not interacting with each other) with a quantized field of two photons. We adapt these exact solutions to the case under consideration. Using explicit wave functions for the resulting electromagnetic field, we calculate the entanglement measure of the photon beam as a function of the applied magnetic field and parameters of the electron medium.
New PVLAS results and limits on magnetically induced optical rotation and ellipticity in vacuum
E. Zavattini; G. Zavattini; G. Raiteri; G. Ruoso; E. Polacco; E. Milotti; V. Lozza; M. Karuza; U. Gastaldi; G. Di Domenico; F. Della Valle; R. Cimino; S. Carusotto; G. Cantatore; M. Bregant
2007-11-22T23:59:59.000Z
IIn 2006 the PVLAS collaboration reported the observation of an optical rotation generated in vacuum by a magnetic field. To further check against possible instrumental artifacts several upgrades to the PVLAS apparatus have been made during the last year. Two data taking runs, at the wavelength of 1064 nm, have been performed in the new configuration with magnetic field strengths of 2.3 T and 5 T. The 2.3 T field value was chosen in order to avoid stray fields. The new observations do not show the presence of a rotation signal down to the levels of $1.2\\cdot 10^{-8}$ rad at 5 T and $1.0\\cdot 10^{-8}$ rad at 2.3 T (at 95% c.l.) with 45000 passes in the magnetic field zone. In the same conditions no ellipticity signal was detected down to $1.4\\cdot 10^{-8}$ at 2.3 T (at 95% c.l.), whereas at 5 T a signal is still present. The physical nature of this ellipticity as due to an effect depending on $B^2$ can be excluded by the measurement at 2.3 T. These new results completely exclude the previously published magnetically induced vacuum dichroism results, indicating that they were instrumental artifacts. These new results therefore also exclude the particle interpretation of the previous PVLAS results as due to a spin zero boson. The background ellipticity at 2.3 T can be used to determine a new limit on the total photon-photon scattering cross section of $\\sigma_{\\gamma\\gamma} < 4.5 \\cdot10^{-34}$ barn at 95% c.l..
Journal of Magnetism and Magnetic Materials ] (
McHenry, Michael E.
magnetic properties were measured with a vibrating sample magnetometer. The mass-specific power loss.40.Rs Keywords: Nanocrystalline alloys; Amorphous alloys; Field annealing; Power loss; Soft magnets the hysteretic power loss while maintaining high-temperature operability [4]. Other goals have included studies
Buz, Jennifer
2011-01-01T23:59:59.000Z
The magnetization of young lunar samples (magnetic fields (e.g. core dynamo and long-lived impact plasma fields) have not been present within the last 1.5 Ga. To better ...
Barclay, John A. (Los Alamos, NM); Steyert, William A. (Los Alamos, NM)
1982-01-01T23:59:59.000Z
The disclosure is directed to an active magnetic regenerator apparatus and method. Brayton, Stirling, Ericsson, and Carnot cycles and the like may be utilized in an active magnetic regenerator to provide efficient refrigeration over relatively large temperature ranges.
Triggering for Magnetic Field Measurements of the LCLS Undulators
Hacker, Kirsten
2010-12-13T23:59:59.000Z
A triggering system for magnetic field measurements of the LCLS undulators has been built with a National Instruments PXI-1002 and a Xylinx FPGA board. The system generates single triggers at specified positions, regardless of encoder sensor jitter about a linear scale.
Impact of Dynamic Magnetic fields on the CLIC Main Beam
Snuverink, J; Jach, C; Jeanneret, JB; Schulte, D; Stulle, F
2010-01-01T23:59:59.000Z
The Compact Linear Collider (CLIC) accelerator has strong precision requirements on the position of the beam. The beam position will be sensitive to external dynamic magnetic fields (stray fields) in the nanotesla regime. The impact of these fields on the CLIC main beam has been studied by performing simulations on the lattices and tolerances have been determined. Several mitigation techniques will be discussed.
Magnetism Theory Group / POSTECH Magnetism Theory Group / POSTECH
Min, Byung Il
Magnetism Theory Group / POSTECH #12;Magnetism Theory Group / POSTECH #12;Magnetism Theory Group / POSTECH #12;Magnetism Theory Group / POSTECH #12;Magnetism Theory Group / POSTECH J.H . Park et al. #12;'s of FeinCsm e tal The chargeandorbitalordering geom etryin YB a C o 2 O 5 S. K. Kwon etal .Magnetism Theory
Observation of low magnetic field density peaks in helicon plasma
Barada, Kshitish K.; Chattopadhyay, P. K.; Ghosh, J.; Kumar, Sunil; Saxena, Y. C. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)
2013-04-15T23:59:59.000Z
Single density peak has been commonly observed in low magnetic field (<100 G) helicon discharges. In this paper, we report the observations of multiple density peaks in low magnetic field (<100 G) helicon discharges produced in the linear helicon plasma device [Barada et al., Rev. Sci. Instrum. 83, 063501 (2012)]. Experiments are carried out using argon gas with m = +1 right helical antenna operating at 13.56 MHz by varying the magnetic field from 0 G to 100 G. The plasma density varies with varying the magnetic field at constant input power and gas pressure and reaches to its peak value at a magnetic field value of {approx}25 G. Another peak of smaller magnitude in density has been observed near 50 G. Measurement of amplitude and phase of the axial component of the wave using magnetic probes for two magnetic field values corresponding to the observed density peaks indicated the existence of radial modes. Measured parallel wave number together with the estimated perpendicular wave number suggests oblique mode propagation of helicon waves along the resonance cone boundary for these magnetic field values. Further, the observations of larger floating potential fluctuations measured with Langmuir probes at those magnetic field values indicate that near resonance cone boundary; these electrostatic fluctuations take energy from helicon wave and dump power to the plasma causing density peaks.
Magnetic susceptibility in QCD
V. D. Orlovsky; Yu. A. Simonov
2014-05-12T23:59:59.000Z
Magnetic susceptibility in the deconfined phase of QCD is calculated in a closed form using a recent general expression for the quark gas pressure in magnetic field. Quark selfenergies are entering the result via Polyakov line factors and ensure the total paramagnetic effect, increasing with temperature. A generalized form of magnetic susceptibility in nonzero magnetic field suitable for experimental and lattice measurements is derived, showing a good agreement with available lattice data.
Walker, Thad Gilbert; Lancor, Brian Robert; Wyllie, Robert
2014-04-15T23:59:59.000Z
Precise measurements of a precessional rate of noble gas in a magnetic field is obtained by constraining the time averaged direction of the spins of a stimulating alkali gas to lie in a plane transverse to the magnetic field. In this way, the magnetic field of the alkali gas does not provide a net contribution to the precessional rate of the noble gas.
Magnetic nanohole superlattices
Liu, Feng
2013-05-14T23:59:59.000Z
A magnetic material is disclosed including a two-dimensional array of carbon atoms and a two-dimensional array of nanoholes patterned in the two-dimensional array of carbon atoms. The magnetic material has long-range magnetic ordering at a temperature below a critical temperature Tc.
Robust Linearization of RF Amplifiers Using NonLinear Internal Model Control Method
Paris-Sud XI, Université de
Robust Linearization of RF Amplifiers Using NonLinear Internal Model Control Method Smail Bachir #1, the nonlinear Internal Model Control (IMC) method is introduced and applied to linearize high frequency Power to be controlled [8]. If the model is a perfect representation of the non linear system, the controller can
Optimal Linear Quadratic Regulator for Markovian Jump Linear Systems, in the
Baras, John S.
, in the last fifteen, the classical paradigms of optimal control for Markovian jump linear systems (see CostaOptimal Linear Quadratic Regulator for Markovian Jump Linear Systems, in the presence of one time] and in the design of controllers Chizeck [1986] of controllers for Markovian jump linear systems. More specifically
Kunkel, Peter
The linear quadratic optimal control problem for linear descriptor systems with variable coefficients Peter Kunkel 3 Volker Mehrmann y 17.01.97 Abstract We study linear quadratic optimal control, 93B11, 93B40 1 Introduction In this paper we study the linearÂquadratic optimal control problem
ENGI 3423 Simple Linear Regression Page 12-01 Simple Linear Regression
George, Glyn
for dealing with non-linear regression are available in the course text, but are beyond the scopeENGI 3423 Simple Linear Regression Page 12-01 Simple Linear Regression Sometimes an experiment predict the value of Y for that value of x . The simple linear regression model is that the predicted
NUMERICAL LINEAR ALGEBRA WITH APPLICATIONS Numer. Linear Algebra Appl. 2005; 12:683
NUMERICAL LINEAR ALGEBRA WITH APPLICATIONS Numer. Linear Algebra Appl. 2005; 12:683 Published Numerical Linear Algebra and its Applications The fourth workshop of the ERCIM Working Group on `Matrix Computations and Statistics' and the First International workshop on `Numerical Linear Algebra and its
Testing epitaxial Co{sub 1.5}Fe{sub 1.5}Ge(001) electrodes in MgO-based magnetic tunnel junctions
Neggache, A. [Institut Jean Lamour, UMR CNRS 7198, Université de Lorraine, 54506 Vandoeuvre lès Nancy (France); Synchrotron SOLEIL-CNRS, L'Orme des Merisiers, Saint-Aubin BP48, 91192 Gif-sur-Yvette (France); Hauet, T.; Petit-Watelot, S.; Boulet, P.; Andrieu, S., E-mail: stephane.andrieu@univ-lorraine.fr [Institut Jean Lamour, UMR CNRS 7198, Université de Lorraine, 54506 Vandoeuvre lès Nancy (France); Bertran, F.; Le Fèvre, P.; Ohresser, P. [Synchrotron SOLEIL-CNRS, L'Orme des Merisiers, Saint-Aubin BP48, 91192 Gif-sur-Yvette (France); Devolder, T. [Institut d'Electronique Fondamentale, CNRS, UMR 8622, 91405 Orsay (France); Mewes, C. [Department of Physics and Astronomy/Center for Materials for Information Technology, University of Alabama, Tuscaloosa, Alabama 35487 (United States); Maat, S.; Childress, J. R. [San Jose Research Center, HGST, a Western Digital company, San Jose, California 95135 (United States)
2014-06-23T23:59:59.000Z
The ability of the full Heusler alloy Co{sub 1.5}Fe{sub 1.5}Ge(001) (CFG) to be a Half-Metallic Magnetic (HMM) material is investigated. Epitaxial CFG(001) layers were grown by molecular beam epitaxy. The results obtained using electron diffraction, X-ray diffraction, and X-ray magnetic circular dichroism are consistent with the full Heusler structure. The pseudo-gap in the minority spin density of state typical in HMM is examined using spin-resolved photoemission. Interestingly, the spin polarization found to be negative at E{sub F} in equimolar CoFe(001) is observed to shift to positive values when inserting Ge in CoFe. However, no pseudo-gap is found at the Fermi level, even if moderate magnetization and low Gilbert damping are observed as expected in HMM materials. Magneto-transport properties in MgO-based magnetic tunnel junctions using CFG electrodes are investigated via spin and symmetry resolved photoemission.
Reticle stage based linear dosimeter
Berger, Kurt W.
2005-06-14T23:59:59.000Z
A detector to measure EUV intensity employs a linear array of photodiodes. The detector is particularly suited for photolithography systems that includes: (i) a ringfield camera; (ii) a source of radiation; (iii) a condenser for processing radiation from the source of radiation to produce a ringfield illumination field for illuminating a mask; (iv) a reticle that is positioned at the ringfield camera's object plane and from which a reticle image in the form of an intensity profile is reflected into the entrance pupil of the ringfield camera, wherein the reticle moves in a direction that is transverse to the length of the ringfield illumination field that illuminates the reticle; (v) detector for measuring the entire intensity along the length of the ringfield illumination field that is projected onto the reticle; and (vi) a wafer onto which the reticle imaged is projected from the ringfield camera.
Reticle stage based linear dosimeter
Berger, Kurt W. (Livermore, CA)
2007-03-27T23:59:59.000Z
A detector to measure EUV intensity employs a linear array of photodiodes. The detector is particularly suited for photolithography systems that includes: (i) a ringfield camera; (ii) a source of radiation; (iii) a condenser for processing radiation from the source of radiation to produce a ringfield illumination field for illuminating a mask; (iv) a reticle that is positioned at the ringfield camera's object plane and from which a reticle image in the form of an intensity profile is reflected into the entrance pupil of the ringfield camera, wherein the reticle moves in a direction that is transverse to the length of the ringfield illumination field that illuminates the reticle; (v) detector for measuring the entire intensity along the length of the ringfield illumination field that is projected onto the reticle; and (vi) a wafer onto which the reticle imaged is projected from the ringfield camera.
Kumar, Dinesh; Bhattacharyya, R. [Udaipur Solar Observatory, Physical Research Laboratory, Dewali, Bari Road, Udaipur-313001 (India)] [Udaipur Solar Observatory, Physical Research Laboratory, Dewali, Bari Road, Udaipur-313001 (India); Smolarkiewicz, P. K. [European Centre for Medium-Range Weather Forecasts, Reading RG2 9AX (United Kingdom)] [European Centre for Medium-Range Weather Forecasts, Reading RG2 9AX (United Kingdom)
2013-11-15T23:59:59.000Z
In ideal magnetohydrodynamics characterized by an infinite electrical conductivity, the magnetic flux across an arbitrary fluid surface is conserved in time. The magnetofluid then can be partitioned into contiguous subvolumes of fluid, each of which entraps its own subsystem of magnetic flux. During dynamical evolution of the magnetofluid, these subvolumes press into each other; and in the process, two such subvolumes may come into direct contact while ejecting a third interstitial subvolume. Depending on the orientations of magnetic fields of the two interacting subvolumes, the magnetic field at the common surface of interaction may become discontinuous and a current sheet is formed there. This process of current sheet formation and their subsequent decay is believed to be a plausible mechanism for coronal heating and may also be responsible for various eruptive phenomena at the solar corona. In this work, we explore this theoretical concept through numerical simulations of a viscous, incompressible magnetofluid characterized by infinite electrical conductivity. In particular, we show that if the initial magnetic field is prescribed by superposition of two linear force-free fields with different torsion coefficients, then formation of current sheets are numerically realizable in the neighborhood of magnetic nulls.
Summary of HQ01e magnetic measurements
Wang, X.; Caspi, S.; Cheng, D. W.; Dietderich, D. R.; Felice, H.; Ferracin, P.; Godeke, A.; Hafalia, A.R.; Joseph, J. M.; Lizarazo, J.; Marchevsky, M.; Sabbi, G. L.; Ghosh, A.; Schmalzle, J.; Wanderer, P.; Ambrosio, G.; Bossert, R.; Chlachidze, G.; DiMarco, J.; Zlobin, A.V.; Milanese, A.; Todesco, E.
2011-11-28T23:59:59.000Z
The magnetic measurements of HQ01e, a 1 m long LHC Accelerator Research Program (LARP) high-gradient quadrupole model, were performed at 4.4 K and above 40 K at the magnet test facility of LBNL in July 2011. The 120 mm aperture cos2? Nb{sub 3}Sn magnet was designed with accelerator magnet features including alignment and field quality. Conductor-limited gradient was 195 T/m at 4.4 K. During the measurement, a ramp rate of 10 A/s was used and measurements at the nominal current of 14.2 kA (82% of short-sample limit with a gradient of 160 T/m) were performed using the 250 mm long printed-circuit board rotating probe developed by FNAL. At 14.2 kA, 2.7 units of b{sub 6} and 0.7 units of b{sub 10} were measured. Large persistent current contribution and strong dynamic effects were observed. We analyzed the allowed and non-allowed harmonics obtained during the measurements above 40 K and at the nominal current. Significant change of the skew sextupole occurred between 50 K and 95 K. The allowed multipole and the low-order non-allowed multipoles at the straight section were explained through the rigid displacement of coil blocks with an amplitude less than 100 ?m. We also attempted to correlate the coil asymmetry (a{sub 3} and b{sub 3}) with the measured coil pole azimuthal strain. The dynamic multipole measured at the magnetic straight section varied linearly with the ramp rate of magnet current ranging from 10 A/s to 60 A/s. It was attributed to the inter-strand coupling currents with low crossover resistance. The crossover resistance of the cables at the inner layer of the magnet was estimated to range between 0.2 ?? to 0.7 ??.
Magnetically attached sputter targets
Makowiecki, D.M.; McKernan, M.A.
1994-02-15T23:59:59.000Z
An improved method and assembly for attaching sputtering targets to cathode assemblies of sputtering systems which includes a magnetically permeable material is described. The magnetically permeable material is imbedded in a target base that is brazed, welded, or soldered to the sputter target, or is mechanically retained in the target material. Target attachment to the cathode is achieved by virtue of the permanent magnets and/or the pole pieces in the cathode assembly that create magnetic flux lines adjacent to the backing plate, which strongly attract the magnetically permeable material in the target assembly. 11 figures.
Non-Linear Seismic Soil Structure Interaction (SSI) Method for...
Office of Environmental Management (EM)
Non-Linear Seismic Soil Structure Interaction (SSI) Method for Developing Non-Linear Seismic SSI Analysis Techniques Non-Linear Seismic Soil Structure Interaction (SSI) Method for...
The chiral magnetic nanomotors
Morozov, Konstantin I
2013-01-01T23:59:59.000Z
Propulsion of the chiral magnetic nanomotors powered by a rotating magnetic field is in the focus of the modern biomedical applications. This technology relies on strong interaction of dynamic and magnetic degrees of freedom of the system. Here we study in detail various experimentally observed regimes of the helical nanomotor orientation and propulsion depending on the actuation frequency, and establish the relation of these two properties with remanent magnetization and geometry of the helical nanomotors. The theoretical predictions for the transition between the regimes and nanomotor orientation and propulsion speed are in excellent agreement with available experimental data. The proposed theory offers a few simple guidelines towards the optimal design of the magnetic nanomotors. In particular, efficient nanomotors should be fabricated of hard magnetics, e.g., cobalt, magnetized transversally and have the geometry of a normal helix with a helical angle of 35-45 degrees.
Rayleigh-Taylor instabilities with sheared magnetic fields
Ruderman, M. S. [Solar Physics and Space Plasma Research Centre (SP2RC), University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH (United Kingdom); Terradas, J.; Ballester, J. L. [Departament de Física, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain)
2014-04-20T23:59:59.000Z
Magnetic Rayleigh-Taylor (MRT) instabilities may play a relevant role in many astrophysical problems. In this work the effect of magnetic shear on the growth rate of the MRT instability is investigated. The eigenmodes of an interface and a slab model under the presence of gravity are analytically calculated assuming that the orientation of the magnetic field changes in the equilibrium, i.e., there is magnetic shear. We solve the linearized magnetohydrodynamic equations in the incompressible regime. We find that the growth rate is bounded under the presence of magnetic shear. We have derived simple analytical expressions for the maximum growth rate, corresponding to the most unstable mode of the system. These expressions provide the explicit dependence of the growth rate on the various equilibrium parameters. For small angles the growth time is linearly proportional to the shear angle, and in this regime the single interface problem and the slab problem tend to the same result. On the contrary, in the limit of large angles and for the interface problem the growth time is essentially independent of the shear angle. In this regime we have also been able to calculate an approximate expression for the growth time for the slab configuration. Magnetic shear can have a strong effect on the growth rates of the instability. As an application of the results found in this paper we have indirectly determined the shear angle in solar prominence threads using their lifetimes and the estimation of the Alfvén speed of the structure.
International Workshop on Linear Colliders 2010
None
2011-10-06T23:59:59.000Z
IWLC2010 International Workshop on Linear Colliders 2010ECFA-CLIC-ILC joint meeting: Monday 18 October - Friday 22 October 2010Venue: CERN and CICG (International Conference Centre Geneva, Switzerland) This year, the International Workshop on Linear Colliders organized by the European Committee for Future Accelerators (ECFA) will study the physics, detectors and accelerator complex of a linear collider covering both CLIC and ILC options.Contact Workshop Secretariat IWLC2010 is hosted by CERN
Summer 2012 Mathematics 317, Linear Algebra
Long, Nicholas
or download a .pdf version for use on a Kindle or Sony Reader or a printable .pdf version. You do not need://linear.ups.edu/xml/latest/fcla-xml-latest.xml Amazon Kindle DX format (optimized PDF): http://linear.ups.edu/download/fcla-kindleDX-2.30.pdf SONY Reader format (optimized PDF for PRS-500, PRS-505): http://linear.ups.edu/download/fcla-sony505-2.30.pdf
Pablo L. Saldanha
2010-02-04T23:59:59.000Z
It is proposed a natural and consistent division of the momentum of electromagnetic waves in linear, non-dispersive and non-absorptive dielectric and magnetic media into material and electromagnetic parts. The material part is calculated using directly the Lorentz force law and the electromagnetic momentum density has the same form than in vacuum, without an explicit dependence on the properties of the media. The consistency of the treatment is verified through the obtention of a correct momentum balance equation in many examples and showing the compatibility of the division with the Einstein's theory of relativity by the use of a gedanken experiment. An experimental prediction for the radiation pressure on mirrors immersed in linear dielectric and magnetic media is also made.
Saldanha, Pablo L
2009-01-01T23:59:59.000Z
It is proposed a natural and consistent division of the momentum of electromagnetic waves in linear, non-dispersive and non-absorptive dielectric and magnetic media into material and electromagnetic parts. The material part is calculated using directly the Lorentz force law and the electromagnetic momentum density has the same form than in vacuum, without an explicit dependence on the properties of the media. The consistency of the treatment is verified through the obtention of a correct momentum balance equation in many examples and showing the compatibility of the division with the Einstein's theory of relativity by the use of a gedanken experiment. An experimental prediction for the radiation pressure on mirrors immersed in linear dielectric and magnetic media is also made.
GENERALIZED DUAL FACE ALGORITHM FOR LINEAR ...
2014-10-02T23:59:59.000Z
1991 Mathematics Subject Classification. Primary 90C05; Secondary 65K05. Key words and phrases. linear programming, dual level face, dual optimal face .
Stochastic linear programming games with concave preferences
2014-12-04T23:59:59.000Z
We study stochastic linear programming games: a class of stochastic ... which include minimum cost spanning trees (Granot and Huberman 1981) as a special
Optimization Online - Equivalence of an Approximate Linear ...
Alejandro Toriello
2013-02-07T23:59:59.000Z
Feb 7, 2013 ... Equivalence of an Approximate Linear Programming Bound with the Held-Karp Bound for the Traveling Salesman Problem. Alejandro Toriello ...
LED Replacements for Linear Fluorescent Lamps Webcast
Broader source: Energy.gov [DOE]
In this June 20, 2011 webcast on LED products marketed as replacements for linear fluorescent lamps, Jason Tuenge of the Pacific Northwest National Laboratory (PNNL) discussed current Lighting...
Linear conic optimization for nonlinear optimal control
2014-07-07T23:59:59.000Z
Jul 7, 2014 ... This linear transport equation is classical in fluid mechanics, statistical ... define a relaxed optimal control problem as an LP in the cone of non-.
Elastic Wave Behavior Across Linear Slip Interfaces
Schoenberg, M.
plane waves incident at arbitrary angles upon a plane linear slip interface are computed ... Also included in these sections is an analysis ... ish, Ut is of the form.
Linear dependence of exponentials - Department of Mathematics ...
2012-09-30T23:59:59.000Z
in the books of the Russian mathematician A. Leontiev. Dear Steven and Sherman,. I recently saw the problem on “linear independence of exponentials”.
Siting the International Linear Collider at Hanford
Kouzes, Richard T.; Asner, David M.; Brodzinski, Ronald L.; Fast, James E.; Miley, Harry S.
2012-03-15T23:59:59.000Z
Review of the proposed International Linear Collider, applications in high energy physics, and evaluation of the Hanford Site as a possible location for siting the facilityl.
Siting the International Linear Collider at Hanford
Kouzes, Richard T.; Asner, David M.; Brodzinski, Ronald L.; Fast, James E.; Miley, Harry S.
2012-05-01T23:59:59.000Z
Review of the proposed International Linear Collider, applications in high energy physics, and evaluation of the Hanford Site as a possible location for siting the facility.
Optimization Online - Linear equalities in blackbox optimization
Charles Audet
2014-05-28T23:59:59.000Z
May 28, 2014 ... ... neither in theory nor in practice. The present work proposes extensions to treat problems with linear equalities whose expression is known.
Optimization Online - Linear, Cone and Semidefinite Programming ...
Strong duality in conic linear programming: facial reduction and extended duals ... A new semide nite programming relaxation for the quadratic assignment ...
Ultra-high vacuum photoelectron linear accelerator
Yu, David U.L.; Luo, Yan
2013-07-16T23:59:59.000Z
An rf linear accelerator for producing an electron beam. The outer wall of the rf cavity of said linear accelerator being perforated to allow gas inside said rf cavity to flow to a pressure chamber surrounding said rf cavity and having means of ultra high vacuum pumping of the cathode of said rf linear accelerator. Said rf linear accelerator is used to accelerate polarized or unpolarized electrons produced by a photocathode, or to accelerate thermally heated electrons produced by a thermionic cathode, or to accelerate rf heated field emission electrons produced by a field emission cathode.
The Linear Complementarity Problem, Lemke Algorithm ...
2011-03-01T23:59:59.000Z
graphs [4], [14], [9] and the research articles in their reference lists. One of the interesting ..... The Linear Complementarity Problem, Academic-Press,. Inc., 1992
Effect of trapping in a degenerate plasma in the presence of a quantizing magnetic field
Shah, H. A.; Iqbal, M. J.; Qureshi, M. N. S. [Department of Physics, GC University, Lahore 54000 (Pakistan); Tsintsadze, N. [Department of Physics, GC University, Lahore 54000 (Pakistan); Institute of Physics, Tbilisi 0177 (Georgia); Masood, W. [Theoretical Physics Division, PINSTECH, P.O. Nilore, Islamabad (Pakistan)
2012-09-15T23:59:59.000Z
Effect of trapping as a microscopic phenomenon in a degenerate plasma is investigated in the presence of a quantizing magnetic field. The plasma comprises degenerate electrons and non-degenerate ions. The presence of the quantizing magnetic field is discussed briefly and the effect of trapping is investigated by using the Fermi-Dirac distribution function. The linear dispersion relation for ion acoustic wave is derived in the presence of the quantizing magnetic field and its influence on the propagation characteristics of the linear ion acoustic wave is discussed. Subsequently, fully nonlinear equations for ion acoustic waves are used to obtain the Sagdeev potential and the investigation of solitary structures. The formation of solitary structures is studied both for fully and partially degenerate plasmas in the presence of a quantizing magnetic field. Both compressive and rarefactive solitons are obtained for different conditions of temperature and magnetic field.
Linear optics, Raman scattering, and spin noise spectroscopy
Glazov, M M
2015-01-01T23:59:59.000Z
Spin noise spectroscopy (SNS) is a new method for studying magnetic resonance and spin dynamics based on measuring the Faraday rotation noise. In strong contrast with methods of nonlinear optics, the spectroscopy of spin noise is considered to be essentially nonperturbative. Presently, however, it became clear that the SNS, as an optical technique, demonstrates properties lying far beyond the bounds of conventional linear optics. Specifically, the SNS shows dependence of the signal on the light power density, makes it possible to penetrate inside an inhomogeneously broadened absorption band and to determine its homogeneous width, allows one to realize an effective pump-probe spectroscopy without any optical nonlinearity, etc. This may seem especially puzzling when taken into account that SNS can be considered just as a version of Raman spectroscopy, which is known to be deprived of such abilities. In this paper, we clarify this apparent inconsistency.
Design and Synthesis of Novel Linear and Cyclic Peptide Ligands for Kappa Opioid Receptors
Fang, Weijie
2008-09-04T23:59:59.000Z
; Nal(2?): 2-naphthylalanine; Nbb: nitrobenzamidobenzyl; Nle: norleucine; norBNI: nor-binaltorphimine; NMR: nuclear magnetic resonance; NSAID: non-steroidal anti-inflammatory drug; OAll: O-allyl; oNBS: ortho-nitrobenzenesulfonyl; ORL-1: opioid... (both linear and cyclic analogs) for ?- opioid receptors have been identified, 1, 25 until recently the search for peptide antagonists 4 has met with limited success. Compounds in which the N-terminus was converted to a tertiary amine...
The Equivalence of Linear Programs and Zero-Sum Games
2012-01-15T23:59:59.000Z
In 1951, Dantzig showed the equivalence of linear programming problems and ... This note concerns the equivalence between linear programming (LP) ...
Passive magnetic bearing system
Post, Richard F.
2014-09-02T23:59:59.000Z
An axial stabilizer for the rotor of a magnetic bearing provides external control of stiffness through switching in external inductances. External control also allows the stabilizer to become a part of a passive/active magnetic bearing system that requires no external source of power and no position sensor. Stabilizers for displacements transverse to the axis of rotation are provided that require only a single cylindrical Halbach array in its operation, and thus are especially suited for use in high rotation speed applications, such as flywheel energy storage systems. The elimination of the need of an inner cylindrical array solves the difficult mechanical problem of supplying support against centrifugal forces for the magnets of that array. Compensation is provided for the temperature variation of the strength of the magnetic fields of the permanent magnets in the levitating magnet arrays.
W. B. Vasantha Kandasamy; Florentin Smarandache
2009-02-01T23:59:59.000Z
This book is a continuation of the book n-linear algebra of type I and its applications. Most of the properties that could not be derived or defined for n-linear algebra of type I is made possible in this new structure: n-linear algebra of type II which is introduced in this book. In case of n-linear algebra of type II we are in a position to define linear functionals which is one of the marked difference between the n-vector spaces of type I and II. However all the applications mentioned in n-linear algebras of type I can be appropriately extended to n-linear algebras of type II. Another use of n-linear algebra (n-vector spaces) of type II is that when this structure is used in coding theory we can have different types of codes built over different finite fields whereas this is not possible in the case of n-vector spaces of type I. Finally in the case of n-vector spaces of type II, we can obtain n-eigen values from distinct fields; hence, the n-characteristic polynomials formed in them are in distinct different fields. An attractive feature of this book is that the authors have suggested 120 problems for the reader to pursue in order to understand this new notion. This book has three chapters. In the first chapter the notion of n-vector spaces of type II are introduced. This chapter gives over 50 theorems. Chapter two introduces the notion of n-inner product vector spaces of type II, n-bilinear forms and n-linear functionals. The final chapter suggests over a hundred problems. It is important that the reader is well-versed not only with linear algebra but also n-linear algebra of type I.
Christiansen, D.W.; Brown, W.F.
1984-01-01T23:59:59.000Z
A welder is described for automated closure of fuel pins by a pulsed magnetic process in which the open end of a length of cladding is positioned within a complementary tube surrounded by a pulsed magnetic welder. Seals are provided at each end of the tube, which can be evacuated or can receive tag gas for direct introduction to the cladding interior. Loading of magnetic rings and end caps is accomplished automatically in conjunction with the welding steps carried out within the tube.
Marts, Donna J. (Idaho Falls, ID); Richardson, John G. (Idaho Falls, ID); Albano, Richard K. (Idaho Falls, ID); Morrison, Jr., John L. (Idaho Falls, ID)
1995-01-01T23:59:59.000Z
This invention discloses a D.C. magnetic latching solenoid that retains a moving armature in a first or second position by means of a pair of magnets, thereby having a zero-power requirement after actuation. The first or second position is selected by reversing the polarity of the D.C. voltage which is enough to overcome the holding power of either magnet and transfer the armature to an opposite position. The coil is then de-energized.
Chiral transition in a strong magnetic background
Eduardo S. Fraga; Ana Júlia Mizher
2008-04-09T23:59:59.000Z
The presence of a strong magnetic background can modify the nature and the dynamics of the chiral phase transition at finite temperature. We compute the modified effective potential in the linear sigma model with quarks to one loop in the $\\bar{MS}$ scheme for $N_{f}=2$. For fields $eB\\sim 5 m_{\\pi}^{2}$ and larger a crossover is turned into a weak first-order transition. We discuss possible implications for non-central heavy ion collisions at RHIC and LHC, and for the primordial QCD transition.
Magnetic fields of the W4 superbubble
Gao, X Y; Reich, P; Han, J L; Kothes, R
2015-01-01T23:59:59.000Z
Superbubbles and supershells are the channels for transferring mass and energy from the Galactic disk to the halo. Magnetic fields are believed to play a vital role in their evolution. We study the radio continuum and polarized emission properties of the W4 superbubble to determine its magnetic field strength. New sensitive radio continuum observations were made at 6 cm, 11 cm, and 21 cm. The total intensity measurements were used to derive the radio spectrum of the W4 superbubble. The linear polarization data were analysed to determine the magnetic field properties within the bubble shells. The observations show a multi-shell structure of the W4 superbubble. A flat radio continuum spectrum that stems from optically thin thermal emission is derived from 1.4 GHz to 4.8 GHz. By fitting a passive Faraday screen model and considering the filling factor fne , we obtain the thermal electron density ne = 1.0/\\sqrt{fne} (\\pm5%) cm^-3 and the strength of the line-of-sight component of the magnetic field B// = -5.0/\\sq...
The Stability of Magnetized Rotating Plasmas with Superthermal Fields
Pessah, M E
2004-01-01T23:59:59.000Z
During the last decade it has become evident that the magnetorotational instability is at the heart of the enhanced angular momentum transport in weakly magnetized accretion disks around neutron stars and black holes. In this paper, we investigate the local linear stability of differentially rotating, magnetized flows and the evolution of the magnetorotational instability beyond the weak-field limit. We show that, when superthermal toroidal fields are considered, both compressibility and magnetic tension terms, related to the curvature of toroidal field lines, should be taken fully into account. We demonstrate that, contrary to the results of most previous investigations, the presence of a toroidal component in the magnetic field plays a crucial role not only in the growth rates of the unstable modes but also in determining which modes are subject to instabilities. We find that, for rotationally supported configurations, the magnetorotational instability is stabilized at low wavenumbers for toroidal Alfven sp...
MAGNETIC HELICITY IN THE DISSIPATION RANGE OF STRONG IMBALANCED TURBULENCE
Markovskii, S. A.; Vasquez, Bernard J., E-mail: sergei.markovskii@unh.edu, E-mail: bernie.vasquez@unh.edu [Space Science Center, University of New Hampshire, Durham, NH 03824 (United States)
2013-05-01T23:59:59.000Z
Hybrid numerical simulations of freely decaying two-dimensional turbulence are presented. The background magnetic field is perpendicular to the simulation plane, which eliminates linear kinetic Alfven waves from the system. The net magnetic helicity of the initial fluctuations at large scales is zero. The turbulence is set to be imbalanced in the sense that the net cross-helicity is not zero. As the turbulence evolves, it develops nonzero magnetic helicity at smaller scales, in the proton kinetic range. In the quasi-steady state of evolution, the magnetic helicity spectrum has a peak consistent with the solar wind observations. The peak position depends on the plasma beta and correlates with a sharp decline of the cross-helicity spectrum.
X-Ray Diffraction Microscopy of Magnetic Structures
Turner, J.; Lima, E.; Huang, X.; Krupin, O.; Seu, K.; Parks, D.; Kevan, S.; Kisslinger, K.; McNulty, I.; Gambino, R.; Mangin, S.; Roy, S. and Fischer, P.
2011-07-14T23:59:59.000Z
We report the first proof-of-principle experiment of iterative phase retrieval from magnetic x-ray diffraction. By using the resonant x-ray excitation process and coherent x-ray scattering, we show that linearly polarized soft x rays can be used to image both the amplitude and the phase of magnetic domain structures. We recovered the magnetic structure of an amorphous terbium-cobalt thin film with a spatial resolution of about 75 nm at the Co L{sub 3} edge at 778 eV. In comparison with soft x-ray microscopy images recorded with Fresnel zone plate optics at better than 25 nm spatial resolution, we find qualitative agreement in the observed magnetic structure.
Hysteresis in Magnetic Shape Memory Composites: Modeling and Simulation
Conti, Sergio; Rumpf, Martin
2015-01-01T23:59:59.000Z
Magnetic shape memory alloys are characterized by the coupling between a structural phase transition and magnetic one. This permits to control the shape change via an external magnetic field, at least in single crystals. Composite materials with single-crystalline particles embedded in a softer matrix have been proposed as a way to overcome the blocking of the transformation at grain boundaries. We investigate hysteresis phenomena for small NiMnGa single crystals embedded in a polymer matrix for slowly varying magnetic fields. The evolution of the microstructure is studied within the rate-independent variational framework proposed by Mielke and Theil (1999). The underlying variational model incorporates linearized elasticity, micromagnetism, stray field and a dissipation term proportional to the volume swept by the phase boundary. The time discretization is based on an incremental minimization of the sum of energy and dissipation. A backtracking approach is employed to approximately ensure the global minimali...
Holographic Magnetic Phase Transition
Gilad Lifschytz; Matthew Lippert
2009-06-21T23:59:59.000Z
We study four-dimensional interacting fermions in a strong magnetic field, using the holographic Sakai-Sugimoto model of intersecting D4 and D8 branes in the deconfined, chiral-symmetric parallel phase. We find that as the magnetic field is varied, while staying in the parallel phase, the fermions exhibit a first-order phase transition in which their magnetization jumps discontinuously. Properties of this transition are consistent with a picture in which some of the fermions jump to the lowest Landau level. Similarities to known magnetic phase transitions are discussed.
Magnetic Braids Anthony Yeates
Dundee, University of
flux function Main result Conclusion 2. Thermonuclear confinement devices. ITER (Internat'l Thermonuclear Experimental Reactor). Inside the KSTAR tokamak. Correspond to periodic magnetic braids. 4 / 22
Company Name: Linear Technology Corporation Web Site: www.linear.com
New Hampshire, University of
Company Name: Linear Technology Corporation Web Site: www.linear.com Industry: Semiconductor Brief worldwide for three decades. The Company's products provide an essential bridge between our analog world
NUMERICAL LINEAR ALGEBRA WITH APPLICATIONS Numer. Linear Algebra Appl. 2011; 18:961980
De Sterck, Hans
NUMERICAL LINEAR ALGEBRA WITH APPLICATIONS Numer. Linear Algebra Appl. 2011; 18:961980 Published aggregation method of [1], and the Markov chain algebraic multigrid (MCAMG) method of [3] using the OTF
Drozhdin, A.I.; Kashikhin, V.V.; Kashikhin, V.S.; Lopes, M.L.; Mokhov, N.V.; Zlobin, A.V.; /Fermilab; Seryi, Andrei; /SLAC
2011-10-14T23:59:59.000Z
Radiation heat deposition in the superconducting magnets of the Interaction Region (IR) of a linear collider can be a serious issue that limits the magnet operating margins and shortens the material lifetime. Radiation and thermal analyses of the IR quadrupoles in the incoming and extraction beam lines of the ILC are performed in order to determine the magnet limits. This paper presents an analysis of the radial, azimuthal and longitudinal distributions of heat deposition in the incoming and disrupted beam doublets. Operation margins of the magnets based on NbTi superconductor are calculated and compared. The radiation and thermal analysis of the ILC IR quadrupoles based on Rutherford type cables was performed. It was found that the peak radiation heat deposition takes place in the second extraction quadrupole QFEX2. The maximum power density in the coil is {approx}17mW/g. This is rather high, comparing to the proton machines (LHC). However, the fast radial decay of the heat deposition together with the high thermal conductivity of the Rutherford type cable limits the coil temperatures to a moderate level. It was determined that both 2-layer and 4-layer QFEX2 magnet designs have thermal margins of a factor of {approx}4 at the nominal gradient of 31.3 T/m. Because of the large margins, these magnets can easily accommodate possible changes in the IR optics and heat deposition levels.
Molten metal feed system controlled with a traveling magnetic field
Praeg, Walter F. (Palos Park, IL)
1991-01-01T23:59:59.000Z
A continuous metal casting system in which the feed of molten metal is controlled by means of a linear induction motor capable of producing a magnetic traveling wave in a duct that connects a reservoir of molten metal to a caster. The linear induction motor produces a traveling magnetic wave in the duct in opposition to the pressure exerted by the head of molten metal in the reservoir so that p.sub.c =p.sub.g -p.sub.m where p.sub.c is the desired pressure in the caster, p.sub.g is the gravitational pressure in the duct exerted by the force of the head of molten metal in the reservoir, and p.sub.m is the electromagnetic pressure exerted by the force of the magnetic field traveling wave produced by the linear induction motor. The invention also includes feedback loops to the linear induction motor to control the casting pressure in response to measured characteristics of the metal being cast.
ANALYTICAL CALCULATION OF STOKES PROFILES OF ROTATING STELLAR MAGNETIC DIPOLE
Martinez Gonzalez, M. J. [Instituto de Astrofisica de Canarias, Via Lactea s/n, 38200 La Laguna, Tenerife (Spain); Asensio Ramos, A. [Departamento de Astrofisica, Universidad de La Laguna, E-38205 La Laguna, Tenerife (Spain)
2012-08-20T23:59:59.000Z
The observation of the polarization emerging from a rotating star at different phases opens up the possibility to map the magnetic field in the stellar surface thanks to the well-known Zeeman-Doppler imaging. When the magnetic field is sufficiently weak, the circular and linear polarization profiles locally in each point of the star are proportional to the first and second derivatives of the unperturbed intensity profile, respectively. We show that the weak-field approximation (for weak lines in the case of linear polarization) can be generalized to the case of a rotating star including the Doppler effect and taking into account the integration on the stellar surface. The Stokes profiles are written as a linear combination of wavelength-dependent terms expressed as series expansions in terms of Hermite polynomials. These terms contain the surface-integrated magnetic field and velocity components. The direct numerical evaluation of these quantities is limited to rotation velocities not larger than eight times the Doppler width of the local absorption profiles. Additionally, we demonstrate that in a rotating star, the circular polarization flux depends on the derivative of the intensity flux with respect to the wavelength and also on the profile itself. Likewise, the linear polarization depends on the profile and on its first and second derivatives with respect to the wavelength. We particularize the general expressions to a rotating dipole.
Best Linear Unbiased Estimate Motivation for BLUE
Fowler, Mark
1 Chapter 6 Best Linear Unbiased Estimate (BLUE) #12;2 Motivation for BLUE Except for Linear Model to a sub-optimal estimate BLUE is one such sub-optimal estimate Idea for BLUE: 1. Restrict estimate) Advantage of BLUE:Needs only 1st and 2nd moments of PDF Mean & Covariance Disadvantages of BLUE: 1. Sub
On linear programing approach to inventory control
Mayfield, John
On linear programing approach to inventory control problems Zhu received his PhD from Wayne State with inventory control problems under the discounted criterion. The objective is to minimize the discounted total imbeds the inventory control problem into an infinite-dimensional linear program over a space of measures
Architecture of an Automatic Tuned Linear Algebra
GimÃ©nez, Domingo
/01 and PI-34/00788/F5/01. #12;Hierarchical Architecture of a Self-Optimised Lineal Algebra LibraryArchitecture of an Automatic Tuned Linear Algebra Library* Javier Cuenca Domingo GimÃ©nez JosÃ© .... SPt c,z Architecture of a Self-Optimised Linear Algebra Routine (SOLAR) Installation_information n1
Hierarchical Linear Discriminant Analysis for Beamforming
Park, Haesun
model of h-LDA by relating it to the two-way multivariate analysis of variance (MANOVA), which fits well dimension reduction, hierarchical linear discriminant analysis (h-LDA) to a well-known spatial localization1 Hierarchical Linear Discriminant Analysis for Beamforming Jaegul Choo , Barry L. Drake
Soft materials for linear electromechanical energy conversion
Antal Jakli; Nandor Eber
2014-07-29T23:59:59.000Z
We briefly review the literature of linear electromechanical effects of soft materials, especially in synthetic and biological polymers and liquid crystals (LCs). First we describe results on direct and converse piezoelectricity, and then we discuss a linear coupling between bending and electric polarization, which maybe called bending piezoelectricity, or flexoelectricity.
THREE THEOREMS ON LINEAR GROUPS BOGDAN NICA
Nica, Bogdan
1960). A finitely generated linear group over a field of zero characteristic is virtually torsion) a subgroup of GLn(K), where K is a field. If we want to specify the field, we say that the group is linear torsion-free if some finite-index subgroup is torsion-free. As a matter of further termi- nology, Selberg
Thvenin's Theorem Linear two-terminal circuit
Kozick, Richard J.
Thévenin's Theorem Linear two-terminal circuit can be replaced by an equivalent circuit composed at terminals with allResistance at terminals with all independent circuit sources set to zero #12;Norton's Theorem Linear two-terminal circuit can be replaced by an equivalentbe replaced by an equivalent circuit
LOCAL LINEAR PID CONTROLLERS FOR NONLINEAR CONTROL
Slatton, Clint
1 LOCAL LINEAR PID CONTROLLERS FOR NONLINEAR CONTROL Jing Lan1, Jeongho Cho1, Deniz Erdogmus2, Jos}@cnel.ufl.edu, derdogmus@ieee.org, m.a.motter@larc.nasa.gov Abstract Nonlinear PID design is difficult if one approaches modeling approach with traditional linear PID controller design techniques to arrive at a principled
Linear Algebra Notes David A. SANTOS
California at Santa Cruz, University of
Linear Algebra Notes David A. SANTOS dsantos@ccp.edu January 2, 2010 REVISION #12;ii Contents . . . . . . . . . . . . . . . . . . 15 2 Matrices and Matrix Operations 18 2.1 The Algebra of Matrices . . . . . . . . . . . 18 2.3 Diagonalisability . . . . . . . . . . . . . . 143 7.4 Theorem of Cayley and Hamilton . . . . . 147 8 Linear Algebra
Blood Management Using Approximate Linear Programming
Shenoy, Prashant
Blood Management Using Approximate Linear Programming Marek Petrik and Shlomo Zilberstein January 13th, 2009 Marek Petrik and Shlomo Zilberstein () Blood Management Using Approximate Linear ProgrammingJanuary 13th, 2009 1 / 36 #12;Blood Inventory Management Problem Regional blood banks: Aggregate
Linear inductive voltage adders (IVA) for advanced hydrodynamic radiography
Mazarakis, M.G.; Boyes, J.D.; Johnson, D.L. [and others
1998-09-01T23:59:59.000Z
The electron beam which drifts through the multiple cavities of conventional induction linacs (LIA) is replaced in an IVA by a cylindrical metal conductor which extends along the entire length of the device and effectuates the addition of the accelerator cavity voltages. In the approach to radiography, the linear inductive voltage adder drives a magnetically immersed electron diode with a millimeter diameter cathode electrode and a planar anode/bremsstrahlung converter. Both anode and cathode electrodes are immersed in a strong (15--50 T) solenoidal magnetic field. The electron beam cross section is approximately of the same size as the cathode needle and generates a similar size, very intense x-ray beam when it strikes the anode converter. An IVA driven diode can produce electron beams of equal size and energy as a LIA but with much higher currents (40--50 kA versus 4--5 kA), simpler hardware and thus lower cost. The authors present here first experimental validations of the technology utilizing HERMES 3 and SABRE IVA accelerators. The electron beam voltage and current were respectively of the order of 10 MV and 40 kA. X-ray doses of up to 1 kR {at} 1 m and spot sizes as small as 1.7 mm (at 200 R doses) were measured.
Assumptions that imply quantum dynamics is linear
Thomas F. Jordan
2006-01-26T23:59:59.000Z
A basic linearity of quantum dynamics, that density matrices are mapped linearly to density matrices, is proved very simply for a system that does not interact with anything else. It is assumed that at each time the physical quantities and states are described by the usual linear structures of quantum mechanics. Beyond that, the proof assumes only that the dynamics does not depend on anything outside the system but must allow the system to be described as part of a larger system. The basic linearity is linked with previously established results to complete a simple derivation of the linear Schrodinger equation. For this it is assumed that density matrices are mapped one-to-one onto density matrices. An alternative is to assume that pure states are mapped one-to-one onto pure states and that entropy does not decrease.
Charge and magnetization inhomogeneities in diluted magnetic semiconductors
Timm, Carsten
2006-03-01T23:59:59.000Z
It is predicted that III-V diluted magnetic semiconductors can exhibit stripelike modulations of magnetization and carrier concentration. This inhomogeneity results from the strong dependence of the magnetization on the carrier concentration. Within...
Khater, A.H.; Moawad, S.M.; Callebaut, D.K. [Department of Mathematics, Faculty of Science, Cairo University, Beni-Suef (Egypt); Departement Natuurkunde, Campus Drie Eiken, Universiteit Antwerpen - UA, B-2610 Antwerpen (Belgium)
2005-01-01T23:59:59.000Z
The equilibrium and Lyapunov stability properties for two-dimensional ideal magnetohydrodynamic (MHD) plasmas with incompressible and homogeneous (i.e., constant density) flows are investigated. In the unperturbed steady state, both the velocity and magnetic field are nonzero and have three components in a Cartesian coordinate system with translational symmetry (i.e., one ignorable spatial coordinate). It is proved that (a) the solutions of the ideal MHD steady state equations with incompressible and homogeneous flows in the plane are also valid for equilibria with the axial velocity component being a free flux function and the axial magnetic field component being a constant (b) the conditions of linearized Lyapunov stability for these MHD flows in the planar case (in which the fields have only two components) are also valid for symmetric equilibria that have a nonplanar velocity field component as well as a nonplanar magnetic field component. On using the method of convexity estimates, nonlinear stability conditions are established.
Linear Transformations In this Chapter, we will define the notion of a linear transformation between
Carrell, Jim
Chapter 6 Linear Transformations In this Chapter, we will define the notion of a linear transformation between two vector spaces V and W which are defined over the same field and prove the most basic transformations is equivalent to matrix theory. We will also study the geometric properties of linear
Acclerator R&D for a Linear Collider
Rubin, D.L.; Dugan, G.; Gibbons, L.; Palmer, M.; Patterson, R.; Sagan, D.; Smith, J.C.; Tenenbaum, P.; Woodley, M.; Fields, J.; Urban, J.
2008-11-26T23:59:59.000Z
The goal of this project was to perform simulations of beam transport in linear colliders, with an emphasis on emittance dilution, spin polarization transport, and development and testing of beam based tuning algorithms. Our simulations are based on an existing object-oriented particle-tracking library, Bmad. To facilitate the efficient development of simulations, an accelerator design and analysis program based on Bmad has been developed called Tao (Tool for Accelerator Optics). The three beam-based alignment algorithms, Dispersion Free Steering, Ballistic Alignment (BA), and the Kubo Method have been implemented in Tao. We have studied the effects of magnet misalignments, BPM resolution, beam jitter, stray fields, BPM and steering magnet failure and the effects of various cavity shape wakefields. A parametric study has been conducted in the presence of the above types of errors for all three alignment algorithms. We find that BPM resolution has only modest impact on the effectiveness of beam based alignment. The DFS correction algorithm was found to be very robust in situations where there were BPM and/or steering magnet failures. The wakefields in the main linac are very weak and cause negligible emittance growth. Spin tracking was extended to study all accelerator components between the damping ring and the interaction point, including RF cavities and the helical undulator. We find that there is no significant depolarization in the RTML, main linac or beam delivery system and that the polarization is relatively insensitive to misalignment. We have developed an effective spin rotator. During the final year of the grant we exploited the computing power of our new linux cluster, along with the modeling codes that we had developed, to investigate damping ring physics and design, specifically as it relates to the CESR Test Accelerator project.
Meulenberg, R W; Lee, J I; McCall, S K
2009-10-19T23:59:59.000Z
The work conducted in this project was conducted with the aim of identifying and understanding the origin and mechanisms of magnetic behavior in undoped semiconductor nanocrystals (NCs), specifically those composed of CdSe. It was anticipated that the successful completion of this task would have the effect of addressing and resolving significant controversy over this topic in the literature. Meanwhile, application of the resultant knowledge was expected to permit manipulation of the magnetic properties, particularly the strength of any magnetic effects, which is of potential relevance in a range of advanced technologies. More specifically, the project was designed and research conducted with the goal of addressing the following series of questions: (1) How does the magnitude of the magnetism in CdSe NCs change with the organic molecules used to passivate their surface the NC size? i.e. Is the magnetism an intrinsic effect in the nanocrystalline CdSe (as observed for Au NCs) or a surface termination driven effect? (2) What is the chemical (elemental) nature of the magnetism? i.e. Are the magnetic effects associated with the Cd atoms or the Se atoms or both? (3) What is/are the underlying mechanism(s)? (4) How can the magnetism be controlled for further applications? To achieve this goal, several experimental/technical milestones were identified to be fulfilled during the course of the research: (A) The preparation of well characterized CdSe NCs with varying surface termination (B) Establishing the extent of the magnetism of these NCs using magnetometry (particularly using superconducting interference device [SQUID]) (C) Establishing the chemical nature of the magnetism using x-ray magnetic circular dichroism (XMCD) - the element specific nature of the technique allows identification of the element responsible for the magnetism (D) Identification of the effect of surface termination on the empty densities of states (DOS) using x-ray absorption spectroscopy (XAS), with particular emphasis on elucidating small changes in the d-electron count. Characterizing changes in the d-electron density can yield important insight into the mechanisms of magnetism in materials. As the three attached manuscripts illustrate (presented in preprint form to ensure no infringement of copyright), each of these milestones was successfully illustrated and the results published in the scientific literature during the course of the project. The research team members were able to determine, from a series of XAS, XMCD and SQUID magnetometry measurements, that CdSe NCs are paramagnetic and that the magnitude of magnetic susceptibility is dependent upon the type of organic molecule used to passivate the NC surface (i.e. the observed magnetism results, at least in part, from a surface effect that is not intrinsic to the NCs). In addition, they identified that the mechanism by which the magnetic susceptibility is modified - via {pi} back-donation of d-electrons to the organic ligands from the Cd atoms. These findings demonstrate that the magnetic properties are related to the surface Cd atoms and illustrate the means by which the magnetic behavior can be manipulated for specific technological applications. Two of the papers published during the course of the LW project do not contain magnetometry data, but focus on the evolution in electronic structure of the CdSe NCs as a function of particle size. These measurements were crucial in developing an understanding of the electronic behavior of the NCs and, ultimately, in assigning the p back-donation mechanism for inducing controllable paramagnetic behavior. Significantly, the research team has also filed a patent application based upon their research: 'Method for Creating Ligand Induced Paramagnetism in Nanocrystalline Structures' Docket: IL-11858. It is noted that both LDRD-LW and Office of Basic Energy Sciences (OBES) funding is acknowledged in the attached manuscripts. As such, is important to indicate that funds were not comingled during the course of the project. Some of the experimental data presente
Journal of Magnetism and Magnetic Materials 252 (2002) 159161 Magnetically induced alignment of FNS
Reznikov, Yuri
Journal of Magnetism and Magnetic Materials 252 (2002) 159Â161 Magnetically induced alignment the observation of magnetically controlled anchoring of ferro-nematic suspensions. We found that application of a weak magnetic field to a cell with the ferro-suspension induces an easy orientation axis with weak
High Temperature, Permanent Magnet Biased Magnetic Bearings
Gandhi, Varun R.
2010-07-14T23:59:59.000Z
, then the molding process was carried out to form the potting cement on the each stator. After this the stators are baked in the oven and once ready the magnets and back-irons are put onto the stator. Shown below in Figure 3-11 is an assembly tool designed... rings. The bearing and its support rings were then carried onto the test rig and mounted at one end of the table. Throughout the assembly process a lot of care had to be taken so as to avoid damaging of the permanent magnets, stator and its coils...
Magnetic Gas Sensing Using a Dilute Magnetic Semiconductor. ...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Abstract: The authors report on a magnetic gas sensing methodology to detect hydrogen using the ferromagnetic properties of a nanoscale dilute magnetic semiconductor...
Free Magnetic Energy in Solar Active Regions above the Minimum-Energy Relaxed State
S. Regnier; E. R. Priest
2008-05-12T23:59:59.000Z
To understand the physics of solar flares, including the local reorganisation of the magnetic field and the acceleration of energetic particles, we have first to estimate the free magnetic energy available for such phenomena, which can be converted into kinetic and thermal energy. The free magnetic energy is the excess energy of a magnetic configuration compared to the minimum-energy state, which is a linear force-free field if the magnetic helicity of the configuration is conserved. We investigate the values of the free magnetic energy estimated from either the excess energy in extrapolated fields or the magnetic virial theorem. For four different active regions, we have reconstructed the nonlinear force-free field and the linear force-free field corresponding to the minimum-energy state. The free magnetic energies are then computed. From the energy budget and the observed magnetic activity in the active region, we conclude that the free energy above the minimum-energy state gives a better estimate and more insights into the flare process than the free energy above the potential field state.
Superconducting Magnet Division
Ohta, Shigemi
Superconducting Magnet Division MAGNETIC DESIGN OF E-LENS SOLENOID AND CORRECTOR SYSTEM FOR RHIC* R.6 A gun collectors gun Combined Horizontal and Vertical Corrector Design Both types of dipole correctors. Gupta, M. Anerella, W. Fischer, G. Ganetis, X. Gu, A. Ghosh, A. Jain, P. Kovach, A. Marone, S. Plate, A
Passive magnetic bearing configurations
Post, Richard F. (Walnut Creek, CA)
2011-01-25T23:59:59.000Z
A journal bearing provides vertical and radial stability to a rotor of a passive magnetic bearing system when the rotor is not rotating and when it is rotating. In the passive magnetic bearing system, the rotor has a vertical axis of rotation. Without the journal bearing, the rotor is vertically and radially unstable when stationary, and is vertically stable and radially unstable when rotating.
Active Magnetic Regenerator Experimental Optimization
Victoria, University of
the potential to create more efficient and compact refrigeration devices is an Active Magnetic Regenerative temperature refrigerators, as well as efficient gas liquefaction plants (AMRLs). Active Magnetic Regenerator Refrigeration exploits the magnetocaloric effect displayed by magnetic materials whereby a reversible
Determining the minimum mass and cost of a magnetic refrigerator
Bjørk, R; Bahl, C R H; Pryds, N
2014-01-01T23:59:59.000Z
An expression is determined for the mass of the magnet and magnetocaloric material needed for a magnetic refrigerator and these are determined using numerical modeling for both parallel plate and packed sphere bed regenerators as function of temperature span and cooling power. As magnetocaloric material Gd or a model material with a constant adiabatic temperature change, representing a infinitely linearly graded refrigeration device, is used. For the magnet a maximum figure of merit magnet or a Halbach cylinder is used. For a cost of \\$40 and \\$20 per kg for the magnet and magnetocaloric material, respectively, the cheapest 100 W parallel plate refrigerator with a temperature span of 20 K using Gd and a Halbach magnet has 0.8 kg of magnet, 0.3 kg of Gd and a cost of \\$35. Using the constant material reduces this cost to \\$25. A packed sphere bed refrigerator with the constant material costs \\$7. It is also shown that increasing the operation frequency reduces the cost. Finally, the lowest cost is also found a...
Magnetic moments of T=3/2 mirror pairs
Perez, S. M. [Department of Physics, University of Cape Town, Private Bag, Rondebosch 7700 (South Africa); iThemba LABS, P. O. Box 722, Somerset West 7129 (South Africa); Richter, W. A. [Department of Physics, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa); Brown, B. A. [Department of Physics and Astronomy, and National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824-1321 (United States); Horoi, M. [Department of Physics, Central Michigan University, Mount Pleasant, Michigan 48859 (United States)
2010-12-15T23:59:59.000Z
We predict values of the magnetic moments of T=3/2 proton-rich fp-shell nuclei in the mass range A=43-53, by using known values for their neutron-rich mirrors together with shell-model estimates for small quantities. We extend the analysis to those T=3/2 sd-shell mirror pairs for which both the T{sub z}=-3/2 and T{sub z}=+3/2 magnetic moments have been measured. We find that these obey the same linear relation as previously deduced for T=1/2 mirror pairs.
Rayleigh-Taylor instability in quantum magnetized viscous plasma
Hoshoudy, G. A., E-mail: g_hoshoudy@yahoo.com [South Valley University, Department of Applied Mathematics, Faculty of Science (Egypt)
2011-09-15T23:59:59.000Z
Quantum effects on Rayleigh-Taylor instability of stratified viscous plasmas layer under the influence of vertical magnetic field are investigated. By linearly solving the viscous QMHD equations into normal mode, a forth-order ordinary differential equation is obtained to describe the velocity perturbation. Then the growth rate is derived for the case where a plasma with exponential density distribution is confined between two rigid planes. The results show that, the presence of vertical magnetic field beside the quantum effect will bring about more stability on the growth rate of unstable configuration for viscous plasma, which is greater than that of inviscous plasma.
Review and comparison of magnet designs for magnetic refrigeration
Bjørk, R; Smith, A; Pryds, N
2014-01-01T23:59:59.000Z
One of the key issues in magnetic refrigeration is generating the magnetic field that the magnetocaloric material must be subjected to. The magnet constitutes a major part of the expense of a complete magnetic refrigeration system and a large effort should therefore be invested in improving the magnet design. A detailed analysis of the efficiency of different published permanent magnet designs used in magnetic refrigeration applications is presented in this paper. Each design is analyzed based on the generated magnetic flux density, the volume of the region where this flux is generated and the amount of magnet material used. This is done by characterizing each design by a figure of merit magnet design efficiency parameter, $\\Lambda_\\mathrm{cool}$. The designs are then compared and the best design found. Finally recommendations for designing the ideal magnet design are presented based on the analysis of the reviewed designs.
Linear phase distribution of acoustical vortices
Gao, Lu; Zheng, Haixiang [Key Laboratory of Optoelectronics of Jiangsu Province, School of Physics Science and Technology, Nanjing Normal University, 1 Wenyuan Road, Xianlin District, Nanjing 210023 (China); Ma, Qingyu, E-mail: maqingyu@njnu.edu.cn [Key Laboratory of Optoelectronics of Jiangsu Province, School of Physics Science and Technology, Nanjing Normal University, 1 Wenyuan Road, Xianlin District, Nanjing 210023 (China); Laboratory of Modern Acoustics of MOE, Nanjing University, Nanjing 210093 (China); Tu, Juan; Zhang, Dong [Laboratory of Modern Acoustics of MOE, Nanjing University, Nanjing 210093 (China)
2014-07-14T23:59:59.000Z
Linear phase distribution of phase-coded acoustical vortices was theoretically investigated based on the radiation theory of point source, and then confirmed by experimental measurements. With the proposed criterion of positive phase slope, the possibility of constructing linear circular phase distributions is demonstrated to be determined by source parameters. Improved phase linearity can be achieved at larger source number, lower frequency, smaller vortex radius, and/or longer axial distance. Good agreements are observed between numerical simulations and measurement results for circular phase distributions. The favorable results confirm the feasibility of precise phase control for acoustical vortices and suggest potential applications in particle manipulation.
Optically isolated signal coupler with linear response
Kronberg, James W. (Aiken, SC)
1994-01-01T23:59:59.000Z
An optocoupler for isolating electrical signals that translates an electrical input signal linearly to an electrical output signal. The optocoupler comprises a light emitter, a light receiver, and a light transmitting medium. The light emitter, preferably a blue, silicon carbide LED, is of the type that provides linear, electro-optical conversion of electrical signals within a narrow wavelength range. Correspondingly, the light receiver, which converts light signals to electrical signals and is preferably a cadmium sulfide photoconductor, is linearly responsive to light signals within substantially the same wavelength range as the blue LED.
LED Linear Lamps and Troffer Lighting
Broader source: Energy.gov [DOE]
The CALiPER program performed a series of investigations on linear LED lamps. Each report in the series covers the performance of up to 31 linear LED lamps, which were purchased in late 2012 or 2013. The first report focuses on bare lamp performance of LED T8 replacement lamps and subsequent reports examine performance in various troffers, as well as cost-effectiveness. There is also a concise guidance document that describes the findings of the Series 21 studies and provides practical advice to manufacturers, specifiers, and consumers (Report 21.4: Summary of Linear (T8) LED Lamp Testing , 5 pages, June 2014).
Tower systems for Linearly repetitive Delone sets
José Aliste-Prieto; Daniel Coronel
2010-03-22T23:59:59.000Z
In this paper we study linearly repetitive Delone sets and prove, following the work of Bellissard, Benedetti and Gambaudo, that the hull of a linearly repetitive Delone set admits a properly nested sequence of box decompositions (tower system) with strictly positive and uniformly bounded (in size and norm) transition matrices. This generalizes a result of Durand for linearly recurrent symbolic systems. Furthermore, we apply this result to give a new proof of a classic estimation of Lagarias and Pleasants on the rate of convergence of patch-frequencies.
Condensed Matter and Magnet Science
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
and HC) Suite of nondestructive pulsed magnets up to 100 tesla Thermoacoustics and fluid dynamics Transport, magnetism, and thermodynamic characterization at extreme conditions of...
QUENCHES IN LARGE SUPERCONDUCTING MAGNETS
Eberhard, P.H.
2010-01-01T23:59:59.000Z
QUENCHES IN LARGE SUPERCONDUCTING MAGNETS. P. H. Eberhard,Study of an Unprotected Superconducting Coil Going Normal,"Method for Testing Superconducting Magnets," LBL Physics
Large Magnetization at Carbon Surfaces
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Large Magnetization at Carbon Surfaces Large Magnetization at Carbon Surfaces Print Wednesday, 31 August 2011 00:00 From organic matter to pencil lead, carbon is a versatile...
Journal of Magnetism and Magnetic Materials ] (
Schumann, Rolf
width of internal field fluctuations. For the ``normal'' TR of the metallic magnets SmCo5; Sm2Co17 of the parameters for SmCo5 and barium ferrite. Susceptibility measurements with small alternating fields, carried out at different points of the TR curve, as well as repeating TR-experiments at SmCo5 demonstrate
Interface and magnetic characterization of ultrathin EuO films with XMCD
Negusse, E.
2009-01-01T23:59:59.000Z
dichroism (XMCD) at the europium M 5 and copper L 3 edges.the available oxides of europium by comparing the measuredtwo common oxides of europium used to identify the relative
Computing nonlinear force free coronal magnetic fields
T. Wiegelmann; T. Neukirch
2008-01-21T23:59:59.000Z
Knowledge of the structure of the coronal magnetic field is important for our understanding of many solar activity phenomena, e.g. flares and CMEs. However, the direct measurement of coronal magnetic fields is not possible with present methods, and therefore the coronal field has to be extrapolated from photospheric measurements. Due to the low plasma beta the coronal magnetic field can usually be assumed to be approximately force free, with electric currents flowing along the magnetic field lines. There are both observational and theoretical reasons which suggest that at least prior to an eruption the coronal magnetic field is in a nonlinear force free state. Unfortunately the computation of nonlinear force free fields is way more difficult than potential or linear force free fields and analytic solutions are not generally available. We discuss several methods which have been proposed to compute nonlinear force free fields and focus particularly on an optimization method which has been suggested recently. We compare the numerical performance of a newly developed numerical code based on the optimization method with the performance of another code based on an MHD relaxation method if both codes are applied to the reconstruction of a semi-analytic nonlinear force-free solution. The optimization method has also been tested for cases where we add random noise to the perfect boundary conditions of the analytic solution, in this way mimicking the more realistic case where the boundary conditions are given by vector magnetogram data. We find that the convergence properties of the optimization method are affected by adding noise to the boundary data and we discuss possibilities to overcome this difficulty.
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
that use the polarization properties of synchrotron radiation, such as magnetic Compton scattering and magnetic circular dichroism to name a few, are generally...
GROUP SPARSITY VIA LINEAR-TIME PROJECTION
2008-08-01T23:59:59.000Z
Jul 31, 2008 ... linear regression model subject to a bound on the l1-norm of the coefficients; .... this strategy scales poorly with the number of non-zero groups.
A polynomial projection algorithm for linear programming
2013-05-03T23:59:59.000Z
algorithm is based on a procedure whose input is a homogeneous system of linear ..... In this case s = 0 and the procedure sets the output vector yout to 0.
The Computational Complexity of Linear Optics
Aaronson, Scott
2011-01-01T23:59:59.000Z
We give new evidence that quantum computers---moreover, rudimentary quantum computers built entirely out of linear-optical elements---cannot be efficiently simulated by classical computers. In particular, we define a model ...
Linear Thermodynamics of Rodlike DNA Filtration
Li, Zirui
Linear thermodynamics transportation theory is employed to study filtration of rodlike DNA molecules. Using the repeated nanoarray consisting of alternate deep and shallow regions, it is demonstrated that the complex ...
Photon emission within the linear sigma model
F. Wunderlich; B. Kampfer
2014-12-22T23:59:59.000Z
Soft-photon emission rates are calculated within the linear sigma model. The investigation is aimed at answering the question to which extent the emissivities map out the phase structure of this particular effective model of strongly interacting matter.
TIGHTER LINEAR AND SEMIDEFINITE RELAXATIONS FOR MAX ...
7 by a detailed analysis of the new relaxations. If positive ... Key words. linear relaxation, semide nite relaxation, lift and project, cut polytope, stable set. polytope ..... su ces to consider the circuit inequalities for chordless circuits [7]. Therefore ...
New linear and positive semidefinite programming based ...
2014-04-18T23:59:59.000Z
testing matrix copositivity [10, 25]; (ii) 0-1 linear optimisation problems [35, 36, ...... 1. By letting Mr be the set of polynomials in M of degree less than or equal to r, ...
Magnetization reversal assisted by half antivortex states in nanostructured circular cobalt disks
Lara, A.; Aliev, F. G., E-mail: farkhad.aliev@uam.es [Dpto. Física de la Materia Condensada, Instituto Nicolas Cabrera (INC) and Condensed Matter Physics Institute (IFIMAC), Universidad Autónoma de Madrid, Madrid (Spain); Dobrovolskiy, O. V. [Physikalisches Institut, Goethe University, Frankfurt am Main (Germany); Physics Department, V. Karazin National University, Kharkiv (Ukraine); Prieto, J. L. [Instituto de Sistemas Optoelectrónicos y Microtecnología (ISOM), Universidad Politecnica de Madrid (Spain); Huth, M. [Physikalisches Institut, Goethe University, Frankfurt am Main (Germany)
2014-11-03T23:59:59.000Z
The half antivortex, a fundamental topological structure which determines magnetization reversal of submicron magnetic devices with domain walls, has been suggested also to play a crucial role in spin torque induced vortex core reversal in circular disks. Here, we report on magnetization reversal in circular disks with nanoholes through consecutive metastable states with half antivortices. In-plane anisotropic magnetoresistance and broadband susceptibility measurements accompanied by micromagnetic simulations reveal that cobalt (Co) disks with two and three linearly arranged nanoholes directed at 45° and 135° with respect to the external magnetic field show reproducible step-like changes in the anisotropic magnetoresistance and magnetic permeability due to transitions between different intermediate states mediated by vortices and half antivortices confined to the dot nanoholes and edges, respectively. Our findings are relevant for the development of multi-hole based spintronic and magnetic memory devices.
QPOs: Einstein's gravity non-linear resonances
Paola Rebusco; Marek A. Abramowicz
2006-01-30T23:59:59.000Z
There is strong evidence that the observed kHz Quasi Periodic Oscillations (QPOs) in the X-ray flux of neutron star and black hole sources in LMXRBs are linked to Einstein's General Relativity. Abramowicz&Klu\\'zniak (2001) suggested a non-linear resonance model to explain the QPOs origin: here we summarize their idea and the development of a mathematical toy-model which begins to throw light on the nature of Einstein's gravity non-linear oscillations.
Zeros in linear multivariable control systems
Ewing, Robert Fennell
1974-01-01T23:59:59.000Z
ZEROS IN LINEAR MULTIVARIABLE CONTROL SYSTEMS A Thesis by ROBERT FENNELL EWING Submitted to the Graduate College of Texas A8M University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE August 1974 Major... Control Systems (August 1974) Robert Fennell Ewing, B. S. , Texas A&M University Chairman of Advisory Committee: Dr. J. W. Howze This thesis examines the problem of altering the transfer function matrix of a linear, time-invariant, multivariable system...
Lectures on Numerical Linear Algebra Yunkai Zhou
Zhou, Yunkai
University Dallas, Texas 75075 yzhou@smu.edu Spring, 2013 #12;Acknowledgements The lecture slides benefit. Y. Zhou Math-6316/CS-7366, SMU 2/210 #12;Basic Linear Algebra Spaces: Rn , Cn , Rn×n , Cn×n , Rm. Zhou Math-6316/CS-7366, SMU 3/210 #12;Basic Linear Algebra Spaces: Rn , Cn , Rn×n , Cn×n , Rm×n , Cm
Lectures on Numerical Linear Algebra Yunkai Zhou
Zhou, Yunkai
University Dallas, Texas 75075 yzhou@smu.edu Spring, 2012 #12;Acknowledgements The lecture slides benefit. Y. Zhou Math-6316/CS-7366, SMU 2/213 #12;Basic Linear Algebra Spaces: Rn , Cn , Rn×n , Cn×n , Rm. Zhou Math-6316/CS-7366, SMU 3/213 #12;Basic Linear Algebra Spaces: Rn , Cn , Rn×n , Cn×n , Rm×n , Cm
Non-linearities in the quantum multiverse
Orfeu Bertolami; Victor Herdeiro
2012-08-01T23:59:59.000Z
It has been recently proposed that the multiverse of eternal inflation and the many-worlds interpretation of quantum mechanics can be identified, yielding a new view on the measure and measurement problems. In the present note, we argue that a non-linear evolution of observables in the quantum multiverse would be an obstacle for such a description and that these non-linearities are expected from quite general arguments.
Permanent magnet energy conversion machine with magnet mounting arrangement
Hsu, John S. (Oak Ridge, TN); Adams, Donald J. (Knoxville, TN)
1999-01-01T23:59:59.000Z
A hybrid permanent magnet dc motor includes three sets of permanent magnets supported by the rotor and three sets of corresponding stators fastened to the surrounding frame. One set of magnets operates across a radial gap with a surrounding radial gap stator, and the other two sets of magnets operate off the respective ends of the rotor across respective axial gaps.
Magnetic Resonance Imaging System Based on Earth's Magnetic Field
Stepi?nik, Janez
Magnetic Resonance Imaging System Based on Earth's Magnetic Field Ales Mohoric,1,* Gorazd Planinsic magnetic field can be partly compensated by the receiving coil design and shielding of electromagnetic pick and must be monitored accurately.[8 10] The importance of NMR in a non-uniform magnetic field
Controllability of second order linear systems Josep Clotet
PolitÃ¨cnica de Catalunya, Universitat
Controllability of second order linear systems Josep Clotet 1 , M a Â¯ Isabel Garc linearization process we study the controllability of second order linear systems. We obtain sufficient-Words: - Two-order linear systems, linearization, feedback, controllability. 1 Introduction The study of second
Piecewise Linear Instrumental Variable Estimation of Causal Influence Richard Scheines
Spirtes, Peter
studies show that when the causal influence of X on Y is non-linear, the piecewise linear linear IV-estimator. In the final section, we describe an experiment comparing regular regression, linearPiecewise Linear Instrumental Variable Estimation of Causal Influence Richard Scheines Dept
Lineal: A linear-algebraic -calculus Pablo Arrighia,1
Dowek, Gilles
Lineal: A linear-algebraic -calculus Pablo Arrighia,1 , Gilles Dowekc aUniversitÂ´e de Grenoble, together with linear algebra. We see this Linear-algebraic -calculus (also referred to as Lineal for short and linear algebra. This language extends the -calculus with the possibility to make arbitrary linear
Lineal: A linear-algebraic -calculus Pablo Arrighia,1
Paris-Sud XI, Université de
Lineal: A linear-algebraic -calculus Pablo Arrighia,1 , Gilles Dowekc aUniversit´e de Grenoble, together with linear algebra. We see this Linear-algebraic -calculus (also referred to as Lineal for short and linear algebra. This language extends the -calculus with the possibility to make arbitrary linear
Bonanos, Peter (East Brunswick, NJ)
1983-01-01T23:59:59.000Z
A toroidal magnet for confining a high magnetic field for use in fusion reactor research and nuclear particle detection. The magnet includes a series of conductor elements arranged about and fixed at its small major radius portion to the outer surface of a central cylindrical support each conductor element having a geometry such as to maintain the conductor elements in pure tension when a high current flows therein, and a support assembly which redistributes all or part of the tension which would otherwise arise in the small major radius portion of each coil element to the large major radius portion thereof.
Lectures on Linear Algebra over Division Ring
Aleks Kleyn
2014-10-11T23:59:59.000Z
In this book i treat linear algebra over division ring. A system of linear equations over a division ring has properties similar to properties of a system of linear equations over a field. However, noncommutativity of a product creates a new picture. Matrices allow two products linked by transpose. Biring is algebra which defines on the set two correlated structures of the ring. As in the commutative case, solutions of a system of linear equations build up right or left vector space depending on type of system. We study vector spaces together with the system of linear equations because their properties have a close relationship. As in a commutative case, the group of automorphisms of a vector space has a single transitive representation on a frame manifold. This gives us an opportunity to introduce passive and active representations. Studying a vector space over a division ring uncovers new details in the relationship between passive and active transformations, makes this picture clearer. Considering of twin representations of division ring in Abelian group leads to the concept of D vector space and their linear map. Based on polyadditive map I considered definition of tensor product of rings and tensor product of D vector spaces.
Modular tokamak magnetic system
Yang, Tien-Fang (Wayland, MA)
1988-01-01T23:59:59.000Z
A modular tokamak system comprised of a plurality of interlocking moldules. Each module is comprised of a vacuum vessel section, a toroidal field coil, moldular saddle coils which generate a poloidal magnetic field and ohmic heating coils.
Geometrically frustrated quantum magnets
NikoliÄ‡ , Predrag, 1974-
2004-01-01T23:59:59.000Z
(cont.) more general lessons on frustrated quantum magnetism. At the end, we demonstrate some new mathematical tools on two other frustrated two-dimensional systems, and summarize our conclusions, with an outlook to remaining ...
Makarov, Sergey V; Krasnok, Alexander E; Belov, Pavel A
2015-01-01T23:59:59.000Z
We propose a novel concept for efficient dynamic tuning of optical properties of a high refractive index subwavelength nanoparticle with a magnetic Mie-type resonance by means of femtosecond laser radiation. This concept is based on ultrafast generation of electron-hole plasma within such nanoparticle, drastically changing its transient dielectric permittivity. This allows to manipulate by both electric and magnetic nanoparticle responses, resulting in dramatic changes of its extinction cross section and scattering diagram. Specifically, we demonstrate the effect of ultrafast switching-on a Huygens source in the vicinity of the magnetic dipole resonance. This approach enables to design ultrafast and compact optical switchers and modulators based on the "ultrafast magnetic light" concept.
Meyer, Ross E. (Los Alamos, NM)
1993-01-01T23:59:59.000Z
A climbing apparatus is provided for climbing ferromagnetic surfaces, such as storage tanks and steel frame structures. A magnet assembly is rotatably mounted in a frame assembly. The frame assembly provides a pair of cam surfaces having different dimensions so that, when the frame is rotated, the cam surfaces contact the ferromagnetic surface to separate the magnet assembly from the surface. The different cam dimensions enable one side of the magnet at a time to be detached from the surface to reduce the effort needed to disengage the climbing apparatus. The cam surface also provides for smoothly attaching the apparatus. A hardened dowel pin is also attached to the frame and the pointed end of the dowel engages the surface when the magnet is attached to the surface to prevent downward sliding movement of the assembly under the weight of the user.
Meyer, R.E.
1993-03-09T23:59:59.000Z
A climbing apparatus is provided for climbing ferromagnetic surfaces, such as storage tanks and steel frame structures. A magnet assembly is rotatably mounted in a frame assembly. The frame assembly provides a pair of cam surfaces having different dimensions so that, when the frame is rotated, the cam surfaces contact the ferromagnetic surface to separate the magnet assembly from the surface. The different cam dimensions enable one side of the magnet at a time to be detached from the surface to reduce the effort needed to disengage the climbing apparatus. The cam surface also provides for smoothly attaching the apparatus. A hardened dowel pin is also attached to the frame and the pointed end of the dowel engages the surface when the magnet is attached to the surface to prevent downward sliding movement of the assembly under the weight of the user.
Constraining primordial magnetic fields with future cosmic shear surveys
Fedeli, C. [Department of Astronomy, University of Florida, 211 Bryant Space Science Center, Gainesville, FL 32611 (United States); Moscardini, L., E-mail: cosimo.fedeli@astro.ufl.edu, E-mail: lauro.moscardini@unibo.it [Dipartimento di Astronomia, Università di Bologna, Via Ranzani 1, 40127 Bologna (Italy)
2012-11-01T23:59:59.000Z
The origin of astrophysical magnetic fields observed in galaxies and clusters of galaxies is still unclear. One possibility is that primordial magnetic fields generated in the early Universe provide seeds that grow through compression and turbulence during structure formation. A cosmological magnetic field present prior to recombination would produce substantial matter clustering at intermediate/small scales, on top of the standard inflationary power spectrum. In this work we study the effect of this alteration on one particular cosmological observable, cosmic shear. We adopt the semi-analytic halo model in order to describe the non-linear clustering of matter, and feed it with the altered mass variance induced by primordial magnetic fields. We find that the convergence power spectrum is, as expected, substantially enhanced at intermediate/small angular scales, with the exact amplitude of the enhancement depending on the magnitude and power-law index of the magnetic field power spectrum. Specifically, for a fixed amplitude, the effect of magnetic fields is larger for larger spectral indices. We use the predicted statistical errors for a future wide-field cosmic shear survey, on the model of the ESA Cosmic Vision mission Euclid, in order to forecast constraints on the amplitude of primordial magnetic fields as a function of the spectral index. We find that the amplitude will be constrained at the level of ? 0.1 nG for n{sub B} ? ?3, and at the level of ? 10{sup ?7} nG for n{sub B} ? 3. The latter is at the same level of lower bounds coming from the secondary emission of gamma-ray sources, implying that for high spectral indices Euclid will certainly be able to detect primordial magnetic fields, if they exist. The present study shows how large-scale structure surveys can be used for both understanding the origins of astrophysical magnetic fields and shedding new light on the physics of the pre-recombination Universe.
Magnetic susceptibility, magnetization, magnetic moment and characterization of Carancas meteorite
Rosales, Domingo
2015-01-01T23:59:59.000Z
On September, 15th, 2007, in the community of Carancas (Puno, Peru) a stony meteorite formed a crater explosive type with a mean diameter of 13.5 m. some samples meteorite fragments were collected. The petrologic analysis performed corresponds to a meteorite ordinary chondrite H 4-5. In this paper we have analyzed the magnetic properties of a meteorite fragment with a proton magnetometer. Also in order to have a complete characterization of the Carancas meteorite and its crater, from several papers, articles and reports, we have made a compilation of the most important characteristics and properties of this meteorite.
A multichannel magnetic probe system for analysing magnetic fluctuations in helical axis plasmas
Haskey, S. R.; Blackwell, B. D.; Seiwald, B.; Hole, M. J.; Pretty, D. G.; Howard, J.; Wach, J. [Plasma Research Laboratory, Research School of Physical Sciences and Engineering, The Australian National University, Canberra, ACT 0200 (Australia)] [Plasma Research Laboratory, Research School of Physical Sciences and Engineering, The Australian National University, Canberra, ACT 0200 (Australia)
2013-09-15T23:59:59.000Z
The need to understand the structure of magnetic fluctuations in H-1NF heliac [S. Hamberger et al., Fusion Technol. 17, 123 (1990)] plasmas has motivated the installation of a sixteen former, tri-axis helical magnetic probe Mirnov array (HMA). The new array complements two existing poloidal Mirnov arrays by providing polarisation information, higher frequency response, and improved toroidal resolution. The helical placement is ideal for helical axis plasmas because it positions the array as close as possible to the plasma in regions of varying degrees of favourable curvature in the magnetohydrodynamic sense, but almost constant magnetic angle. This makes phase variation with probe position near linear, greatly simplifying the analysis of the data. Several of the issues involved in the design, installation, data analysis, and calibration of this unique array are presented including probe coil design, frequency response measurements, mode number identification, orientation calculations, and mapping probe coil positions to magnetic coordinates. Details of specially designed digitally programmable pre-amplifiers, which allow gains and filters to be changed as part of the data acquisition initialisation sequence and stored with the probe signals, are also presented. The low shear heliac geometry [R. Jiménez-Gómez et al., Nucl. Fusion 51, 033001 (2011)], flexibility of the H-1NF heliac, and wealth of information provided by the HMA create a unique opportunity for detailed study of Alfvén eigenmodes, which could be a serious issue for future fusion reactors.
Permanent Magnet Ecr Plasma Source With Magnetic Field Optimization
Doughty, Frank C. (Plano, TX); Spencer, John E. (Plano, TX)
2000-12-19T23:59:59.000Z
In a plasma-producing device, an optimized magnet field for electron cyclotron resonance plasma generation is provided by a shaped pole piece. The shaped pole piece adjusts spacing between the magnet and the resonance zone, creates a convex or concave resonance zone, and decreases stray fields between the resonance zone and the workpiece. For a cylindrical permanent magnet, the pole piece includes a disk adjacent the magnet together with an annular cylindrical sidewall structure axially aligned with the magnet and extending from the base around the permanent magnet. The pole piece directs magnetic field lines into the resonance zone, moving the resonance zone further from the face of the magnet. Additional permanent magnets or magnet arrays may be utilized to control field contours on a local scale. Rather than a permeable material, the sidewall structure may be composed of an annular cylindrical magnetic material having a polarity opposite that of the permanent magnet, creating convex regions in the resonance zone. An annular disk-shaped recurve section at the end of the sidewall structure forms magnetic mirrors keeping the plasma off the pole piece. A recurve section composed of magnetic material having a radial polarity forms convex regions and/or magnetic mirrors within the resonance zone.
Nance, Thomas A. (Aiken, SC)
2009-08-18T23:59:59.000Z
A quick connect/disconnect coupling apparatus is provided in which a base member is engaged by a locking housing through a series of interengagement pins. The pins maintain the shaft in a locked position. Upon exposure to an appropriately positioned magnetic field, pins are removed a sufficient distance such that the shaft may be withdrawn from the locking housing. The ability to lock and unlock the connector assembly requires no additional tools or parts apart from a magnetic key.
Berman, S.M.; Richardson R.W.
1983-12-29T23:59:59.000Z
The radiant emission of a mercury-argon discharge in a fluorescent lamp assembly is enhanced by providing means for establishing a magnetic field with lines of force along the path of electron flow through the bulb of the lamp assembly, to provide Zeeman splitting of the ultraviolet spectral line. Optimum results are obtained when the magnetic field strength causes a Zeeman splitting of approximately 1.7 times the thermal line width.
Telescoping magnetic ball bar test gage
Bryan, J.B.
1982-03-15T23:59:59.000Z
A telescoping magnetic ball bar test gage for determining the accuracy of machine tools, including robots, and those measuring machines having non-disengagable servo drives which cannot be clutched out. Two gage balls are held and separated from one another by a telescoping fixture which allows them relative radial motional freedom but not relative lateral motional freedom. The telescoping fixture comprises a parallel reed flexure unit and a rigid member. One gage ball is secured by a magnetic socket knuckle assembly which fixes its center with respect to the machine being tested. The other gage ball is secured by another magnetic socket knuckle assembly which is engaged or held by the machine in such manner that the center of that ball is directed to execute a prescribed trajectory, all points of which are equidistant from the center of the fixed gage ball. As the moving ball executes its trajectory, changes in the radial distance between the centers of the two balls caused by inaccuracies in the machine are determined or measured by a linear variable differential transformer (LVDT) assembly actuated by the parallel reed flexure unit. Measurements can be quickly and easily taken for multiple trajectories about several different fixed ball locations, thereby determining the accuracy of the machine.
SYNOPTIC MAPPING OF CHROMOSPHERIC MAGNETIC FLUX
Jin, C. L. [Key Laboratory of Solar Activity, National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Harvey, J. W.; Pietarila, A., E-mail: cljin@nao.cas.cn, E-mail: jharvey@nso.edu, E-mail: apietarila@nso.edu [National Solar Observatory, Tucson, AZ 85719 (United States)
2013-03-10T23:59:59.000Z
We used daily full-disk Ca II 854.2 nm magnetograms from the Synoptic Optical Long Term Investigations of the Sun (SOLIS) facility to study the chromospheric magnetic field from 2006 April through 2009 November. We determined and corrected previously unidentified zero offsets in the SOLIS magnetograms. By tracking the disk passages of stable unipolar regions, the measured net flux densities were found to systematically decrease from the disk center to the limb by a factor of about two. This decrease was modeled using a thin flux tube model with a difference in signal formation height between the center and limb sides. Comparison of photospheric and chromospheric observations shows that their differences are largely due to horizontal spreading of magnetic flux with increasing height. The north polar magnetic field decreased nearly linearly with time during our study period while the south polar field was nearly constant. We used the annual change in the viewing angle of the polar regions to estimate the radial and meridional components of the polar fields and found that the south polar fields were tilted away from the pole. Synoptic maps of the chromospheric radial flux density distribution were used as boundary conditions for extrapolation of the field from the chromosphere into the corona. A comparison of modeled and observed coronal hole boundaries and coronal streamer positions showed better agreement when using the chromospheric rather than the photospheric synoptic maps.
Modeling and analysis of a semi-active permanent magnet damper
Lin, Wayne Chinn-Tzu
1992-01-01T23:59:59.000Z
Committee: Dr. Robin C, Redfield A method for employing a linear electromagnetic motor as a semi-active damper is proposed. This strategy is based on two physical principles: Faraday's law and Lenz's law. Unlike a hydraulic damper, which has fluid... compressibility and inertia problems at high input frequencies, the magnetic damper, because of its low inductance, presents minimal complications due to compliance. Furthermore, the linear motor's damping levels can be adjusted electronically, either through a...
Freely oriented portable superconducting magnet
Schmierer, Eric N. (Los Alamos, NM); Prenger, F. Coyne (Los Alamos, NM); Hill, Dallas D. (Los Alamos, NM)
2010-01-12T23:59:59.000Z
A freely oriented portable superconducting magnet is disclosed. Coolant is supplied to the superconducting magnet from a repository separate from the magnet, enabling portability of the magnet. A plurality of support assemblies structurally anchor and thermally isolate the magnet within a thermal shield. A plurality of support assemblies structurally anchor and thermally isolate the thermal shield within a vacuum vessel. The support assemblies restrain movement of the magnet resulting from energizing and cooldown, as well as from changes in orientation, enabling the magnet to be freely orientable.
Magnetic moments of vector, axial, and tensor mesons in lattice QCD
Lee, F X; Wilcox, W
2008-01-01T23:59:59.000Z
We present a calculation of magnetic moments for selected spin-1 mesons using the techniques of lattice QCD. This is carried out by introducing progressively small static magnetic field on the lattice and measuring the linear response of a hadron's mass shift. The calculations are done on $24^4$ quenched lattices using standard Wilson actions, with $\\beta$=6.0 and pion mass down to 500 MeV. The results are compared to those from the form factor method where available.
Hood, R.Q.
1994-04-01T23:59:59.000Z
Utilizing self-consistent Hartree-Fock calculations, several aspects of multilayers and interfaces are explored: enhancement and reduction of the local magnetic moments, magnetic coupling at the interfaces, magnetic arrangements within each film and among non-neighboring films, global symmetry of the systems, frustration, orientation of the various moments with respect to an outside applied field, and magnetic-field induced transitions. Magnetoresistance of ferromagnetic-normal-metal multilayers is found by solving the Boltzmann equation. Results explain the giant negative magnetoresistance encountered in these systems when an initial antiparallel arrangement is changed into a parallel configuration by an external magnetic field. The calculation depends on (1) geometric parameters (thicknesses of layers), (2) intrinsic metal parameters (number of conduction electrons, magnetization, and effective masses in layers), (3) bulk sample properties (conductivity relaxation times), (4) interface scattering properties (diffuse scattering versus potential scattering at the interfaces, and (5) outer surface scattering properties (specular versus diffuse surface scattering). It is found that a large negative magnetoresistance requires considerable asymmetry in interface scattering for the two spin orientations. Features of the interfaces that may produce an asymmetrical spin-dependent scattering are studied: varying interfacial geometric random roughness with no lateral coherence, correlated (quasi-periodic) roughness, and varying chemical composition of the interfaces. The interplay between these aspects of the interfaces may enhance or suppress the magnetoresistance, depending on whether it increases or decreases the asymmetry in the spin-dependent scattering of the conduction electrons.
The Stability of Magnetized Rotating Plasmas with Superthermal Fields
Martin E. Pessah; Dimitrios Psaltis
2005-04-13T23:59:59.000Z
During the last decade it has become evident that the magnetorotational instability is at the heart of the enhanced angular momentum transport in weakly magnetized accretion disks around neutron stars and black holes. In this paper, we investigate the local linear stability of differentially rotating, magnetized flows and the evolution of the magnetorotational instability beyond the weak-field limit. We show that, when superthermal toroidal fields are considered, the effects of both compressibility and magnetic tension forces, which are related to the curvature of toroidal field lines, should be taken fully into account. We demonstrate that the presence of a strong toroidal component in the magnetic field plays a non-trivial role. When strong fields are considered, the strength of the toroidal magnetic field not only modifies the growth rates of the unstable modes but also determines which modes are subject to instabilities. We find that, for rotating configurations with Keplerian laws, the magnetorotational instability is stabilized at low wavenumbers for toroidal Alfven speeds exceeding the geometric mean of the sound speed and the rotational speed. We discuss the significance of our findings for the stability of cold, magnetically dominated, rotating fluids and argue that, for these systems, the curvature of toroidal field lines cannot be neglected even when short wavelength perturbations are considered. We also comment on the implications of our results for the validity of shearing box simulations in which superthermal toroidal fields are generated.
Influence of primordial magnetic fields on 21 cm emission
Dominik R. G. Schleicher; Robi Banerjee; Ralf S. Klessen
2008-12-17T23:59:59.000Z
Magnetic fields in the early universe can significantly alter the thermal evolution and the ionization history during the dark ages. This is reflected in the 21 cm line of atomic hydrogen, which is coupled to the gas temperature through collisions at high redshifts, and through the Wouthuysen-Field effect at low redshifts. We present a semi-analytic model for star formation and the build-up of a Lyman alpha background in the presence of magnetic fields, and calculate the evolution of the mean 21 cm brightness temperature and its frequency gradient as a function of redshift. We further discuss the evolution of linear fluctuations in temperature and ionization in the presence of magnetic fields and calculate the effect on the 21 cm power spectrum. At high redshifts, the signal is increased compared to the non-magnetic case due to the additional heat input into the IGM from ambipolar diffusion and the decay of MHD turbulence. At lower redshifts, the formation of luminous objects and the build-up of a Lyman alpha background can be delayed by a redshift interval of 10 due to the strong increase of the filtering mass scale in the presence of magnetic fields. This tends to decrease the 21 cm signal compared to the zero-field case. In summary, we find that 21 cm observations may become a promising tool to constrain primordial magnetic fields.
EXTENSIONS OF GENERALIZED LINEAR MODELING APPROACH TO STOCHASTIC WEATHER GENERATORS
Katz, Richard
weather) -- Software R open source statistical programming language: Function glm "Family;(2) Generalized Linear Models Statistical Framework -- Multiple Regression Analysis (Linear model or LM) Response
Relationship Between Solar Wind Speed and Coronal Magnetic Field Properties
Fujiki, Ken'ichi; Iju, Tomoya; Hakamada, Kazuyuki; Kojima, Masayoshi
2015-01-01T23:59:59.000Z
We have studied the relationship between the solar-wind speed $[V]$ and the coronal magnetic-field properties (a flux expansion factor [$f$] and photospheric magnetic-field strength [$B_{\\mathrm{S}}$]) at all latitudes using data of interplanetary scintillation and solar magnetic field obtained for 24 years from 1986 to 2009. Using a cross-correlation analyses, we verified that $V$ is inversely proportional to $f$ and found that $V$ tends to increase with $B_{\\mathrm{S}}$ if $f$ is the same. As a consequence, we find that $V$ has extremely good linear correlation with $B_{\\mathrm{S}}/f$. However, this linear relation of $V$ and $B_{\\mathrm{S}}/f$ cannot be used for predicting the solar-wind velocity without information on the solar-wind mass flux. We discuss why the inverse relation between $V$ and $f$ has been successfully used for solar-wind velocity prediction, even though it does not explicitly include the mass flux and magnetic-field strength, which are important physical parameters for solar-wind accele...
Wave propagation and shock formation in different magnetic structures
Rebecca Centeno; Manuel Collados; Javier Trujillo Bueno
2008-10-20T23:59:59.000Z
Velocity oscillations "measured" simultaneously at the photosphere and the chromosphere -from time series of spectropolarimetric data in the 10830 A region- of different solar magnetic features allow us to study the properties of wave propagation as a function of the magnetic flux of the structure (i.e. two different-sized sunspots, a tiny pore and a facular region). While photospheric oscillations have similar characteristics everywhere, oscillations measured at chromospheric heights show different amplitudes, frequencies and stages of shock development depending on the observed magnetic feature. The analysis of the power and the phase spectra, together with simple theoretical modeling, lead to a series of results concerning wave propagation within the range of heights of this study. We find that, while the atmospheric cut-off frequency and the propagation properties of the different oscillating modes depend on the magnetic feature, in all the cases the power that reaches the high chromosphere above the atmospheric cut-off comes directly from the photosphere by means of linear vertical wave propagation rather than from non-linear interaction of modes.
2009 Linear Collider Workshop of the Americas
Seidel, Sally
2009-09-29T23:59:59.000Z
The 2009 Linear Collider Workshop of the Americas was held on the campus of the University of New Mexico from 29 September to 3 October, 2009. This was a joint meeting of the American Linear Collider Physics Group and the ILC Global Design Effort. Two hundred fifty people attended. The number of scientific contributions was 333. The complete agenda, with links to all of the presentations, is available at physics.unm.edu/LCWA09/. The meeting brought together international experts as well as junior scientists, to discuss the physics potential of the linear collider and advances in detector technology. The validation of detector designs was announced, and the detector design groups planned the next phase of the effort. Detector R&D teams reported on progress on many topics including calorimetry and tracking. Recent accelerator design considerations were discussed in a special session for experimentalists and theorists.
Dual-range linearized transimpedance amplifier system
Wessendorf, Kurt O. (Albuquerque, NM)
2010-11-02T23:59:59.000Z
A transimpedance amplifier system is disclosed which simultaneously generates a low-gain output signal and a high-gain output signal from an input current signal using a single transimpedance amplifier having two different feedback loops with different amplification factors to generate two different output voltage signals. One of the feedback loops includes a resistor, and the other feedback loop includes another resistor in series with one or more diodes. The transimpedance amplifier system includes a signal linearizer to linearize one or both of the low- and high-gain output signals by scaling and adding the two output voltage signals from the transimpedance amplifier. The signal linearizer can be formed either as an analog device using one or two summing amplifiers, or alternately can be formed as a digital device using two analog-to-digital converters and a digital signal processor (e.g. a microprocessor or a computer).
Test facilities for future linear colliders
Ruth, R.D.
1995-12-01T23:59:59.000Z
During the past several years there has been a tremendous amount of progress on Linear Collider technology world wide. This research has led to the construction of the test facilities described in this report. Some of the facilities will be complete as early as the end of 1996, while others will be finishing up around the end 1997. Even now there are extensive tests ongoing for the enabling technologies for all of the test facilities. At the same time the Linear Collider designs are quite mature now and the SLC is providing the key experience base that can only come from a working collider. All this taken together indicates that the technology and accelerator physics will be ready for a future Linear Collider project to begin in the last half of the 1990s.
Linear Parameter-Varying versus Linear Time-Invariant Control Design for a Pressurized Water Reactor
Bodenheimer, Bobby
-dependent control to a nuclear pressurized water reactor is investigated and is compared to that of using an H1Linear Parameter-Varying versus Linear Time-Invariant Control Design for a Pressurized Water Reactor Pascale Bendotti y Electricit e de France Direction des Etudes et Recherches 6 Quai Watier, 78401
NUMERICAL LINEAR ALGEBRA WITH APPLICATIONS Numer. Linear Algebra Appl. 2008; 15:115139
De Sterck, Hans
NUMERICAL LINEAR ALGEBRA WITH APPLICATIONS Numer. Linear Algebra Appl. 2008; 15:115139 Published-two interpolation for parallel algebraic multigrid Hans De Sterck1, Robert D. Falgout2, Joshua W. Nolting3, Campus Box 526, Boulder, CO 80302, U.S.A. SUMMARY Algebraic multigrid (AMG) is one of the most efficient
Magnetic monopole and the nature of the static magnetic field
Xiuqing Huang
2008-12-10T23:59:59.000Z
We investigate the factuality of the hypothetical magnetic monopole and the nature of the static magnetic field. It is shown from many aspects that the concept of the massive magnetic monopoles clearly is physically untrue. We argue that the static magnetic field of a bar magnet, in fact, is the static electric field of the periodically quasi-one-dimensional electric-dipole superlattice, which can be well established in some transition metals with the localized d-electron. This research may shed light on the perfect unification of magnetic and electrical phenomena.
Limitations of controlling oscillators via linear augmentation
Rajat Karnatak
2015-02-15T23:59:59.000Z
In this paper, we will have a look at some examples where linear augmentation is used to control oscillatory systems towards their stationary solutions. The simplicity of linear augmentation is a big positive feature of this scheme but at the same time, questions related to the general applicability of this procedure need to be addressed. This work attempts to demonstrate some control instances where this scheme fails to stabilize the required stationary solutions. Examples from conservative as well as dissipative dynamical systems are presented in this regard and a possible application for dissipative predator--prey dynamics is also discussed.
Linear and angular retroreflecting interferometric alignment target
Maxey, L. Curtis (Powell, TN)
2001-01-01T23:59:59.000Z
The present invention provides a method and apparatus for measuring both the linear displacement and angular displacement of an object using a linear interferometer system and an optical target comprising a lens, a reflective surface and a retroreflector. The lens, reflecting surface and retroreflector are specifically aligned and fixed in optical connection with one another, creating a single optical target which moves as a unit that provides multi-axis displacement information for the object with which it is associated. This displacement information is useful in many applications including machine tool control systems and laser tracker systems, among others.
Barclay, J.A.; Steyert, W.A.
1981-01-27T23:59:59.000Z
An apparatus and method for refrigeration are disclosed which provides efficient refrigeration over temperature ranges in excess of 20/sup 0/C and which requires no maintenance and is, therefore, usable on an unmanned satellite. The apparatus comprises a superconducting magnet which may be solenoidal. A piston comprising a substance such as a rare earth substance which is maintained near its Curie temperature reciprocates through the bore of the solenoidal magnet. A magnetic drive rod is connected to the piston and appropriate heat sinks are connected thereto. The piston is driven by a suitable mechanical drive such as an electric motor and cam. In practicing the invention, the body of the piston is magnetized and demagnetized as it moves through the magnetic field of the solenoid to approximate any of the following cycles or a condition thereof as well as, potentially, other cycles: Brayton, Carnot, Ericsson, and Stirling. Advantages of the present invention include: that refrigeration can be accomplished over at least a 20/sup 0/C scale at superconducting temperatures as well as at more conventional temperatures; very high efficiency, high reliability, and small size. (LCL)
Dependence of Brownian and Néel relaxation times on magnetic field strength
Deissler, Robert J., E-mail: rjd42@case.edu; Wu, Yong; Martens, Michael A. [Department of Physics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106 (United States)] [Department of Physics, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, Ohio 44106 (United States)
2014-01-15T23:59:59.000Z
Purpose: In magnetic particle imaging (MPI) and magnetic particle spectroscopy (MPS) the relaxation time of the magnetization in response to externally applied magnetic fields is determined by the Brownian and Néel relaxation mechanisms. Here the authors investigate the dependence of the relaxation times on the magnetic field strength and the implications for MPI and MPS. Methods: The Fokker–Planck equation with Brownian relaxation and the Fokker–Planck equation with Néel relaxation are solved numerically for a time-varying externally applied magnetic field, including a step-function, a sinusoidally varying, and a linearly ramped magnetic field. For magnetic fields that are applied as a step function, an eigenvalue approach is used to directly calculate both the Brownian and Néel relaxation times for a range of magnetic field strengths. For Néel relaxation, the eigenvalue calculations are compared to Brown's high-barrier approximation formula. Results: The relaxation times due to the Brownian or Néel mechanisms depend on the magnitude of the applied magnetic field. In particular, the Néel relaxation time is sensitive to the magnetic field strength, and varies by many orders of magnitude for nanoparticle properties and magnetic field strengths relevant for MPI and MPS. Therefore, the well-known zero-field relaxation times underestimate the actual relaxation times and, in particular, can underestimate the Néel relaxation time by many orders of magnitude. When only Néel relaxation is present—if the particles are embedded in a solid for instance—the authors found that there can be a strong magnetization response to a sinusoidal driving field, even if the period is much less than the zero-field relaxation time. For a ferrofluid in which both Brownian and Néel relaxation are present, only one relaxation mechanism may dominate depending on the magnetic field strength, the driving frequency (or ramp time), and the phase of the magnetization relative to the applied magnetic field. Conclusions: A simple treatment of Néel relaxation using the common zero-field relaxation time overestimates the relaxation time of the magnetization in situations relevant for MPI and MPS. For sinusoidally driven (or ramped) systems, whether or not a particular relaxation mechanism dominates or is even relevant depends on the magnetic field strength, the frequency (or ramp time), and the phase of the magnetization relative to the applied magnetic field.
Maity, Chandan; Chakrabarti, Nikhil [Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064 (India); Sengupta, Sudip [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)
2012-10-15T23:59:59.000Z
In a fluid description, we study space-time evolution of lower hybrid modes in a cold quasi-neutral homogeneous plasma in presence of a background inhomogeneous magnetic field. Within a linear analysis, a dispersion relation with inhomogeneous magnetic field shows 'phase mixing' of such oscillations. A manifestation of 'phase mixing' is shown in 'mode coupling.' By using Lagrangian variables, an exact solution is presented in parametric form of this nonlinear time dependent problem. It is demonstrated that initially excited lower hybrid modes always break via phase mixing phenomenon in presence of an inhomogeneous magnetic field. Breaking of such oscillations is revealed by the appearance of spikes in the plasma density profile.
Beam dynamics performances and applications of a low-energy electron-beam magnetic bunch compressor
Prokop, C R; Carlsten, B E; Church, M
2013-01-01T23:59:59.000Z
Many front-end applications of electron linear accelerators rely on the production of temporally-compressed bunches. The shortening of electron bunches is often realized with magnetic bunch compressors located in high-energy sections of accelerators. Magnetic compression is subject to collective effects including space charge and self interaction via coherent synchrotron radiation. In this paper we explore the application of magnetic compression to low-energy ($\\sim 40$ MeV), high-charge (nC) electron bunches with low normalized transverse emittances ($< 5$ $\\mu$m).
Ion beam oscillation due to fluctuation of a hot filament driven magnetized plasma
Imakita, S.; Kasuya, T.; Kimura, Y.; Wada, M. [Graduate School of Engineering, Doshisha University, Kyoto 610-0321 (Japan); Miyamoto, N. [Nissin Ion Equipment Co. Ltd., Kyoto 601-8205 (Japan)
2010-02-15T23:59:59.000Z
Ion beam current extracted from a modified Bernas type ion source occasionally exhibits an oscillation at a frequency of several 100 kHz. Increase in the strength of a linear magnetic field induced to the ion source has either decreased or increased the frequency of this oscillation. The frequency showed an increase in proportion to the ion extraction voltage when the frequency decreased with increasing magnetic field. The change of extraction voltage did not affect the frequency when the frequency increased with the increasing magnetic field. Mechanisms causing these oscillations of an ion beam had been investigated.
Frustrated Magnetism in Low-Dimensional Lattices
Tovar, Mayra
2011-01-01T23:59:59.000Z
and C. Baines. Quantum magnetism in the paratacamite family:14] Stephen Blundell. Magnetism in Condensed Matter. OxfordElectrons and Quantum Magnetism. Graduate Texts in Con-
Magnetic spectroscopy and microscopy of functional materials
Jenkins, C.A.
2012-01-01T23:59:59.000Z
transitions for magnetic refrigeration. Appl Phys Lett, 97(these e?ects in magnetic refrigeration and actuation makesheat ?ow with the goal of magnetic refrigeration (adiabatic
Superconducting Magnet Technology for Future Hadron Colliders
Scanlan, R.M.
2011-01-01T23:59:59.000Z
I. Superconducting Magnet Technology for Future Hadl"On1994. M.N. Wilson, Superconducting Magnets (Clarendon Press,The application of superconducting magnets to large-scale
Aized, D.; Schwall, R.E.
1999-06-22T23:59:59.000Z
A superconducting magnetic coil includes a plurality of sections positioned axially along the longitudinal axis of the coil, each section being formed of an anisotropic high temperature superconductor material wound about a longitudinal axis of the coil and having an associated critical current value that is dependent on the orientation of the magnetic field of the coil. The cross section of the superconductor, or the type of superconductor material, at sections along the axial and radial axes of the coil are changed to provide an increased critical current at those regions where the magnetic field is oriented more perpendicularly to the conductor plane, to thereby increase the critical current at these regions and to maintain an overall higher critical current of the coil. 15 figs.
Aized, Dawood (Marlboro, MA); Schwall, Robert E. (Northborough, MA)
1999-06-22T23:59:59.000Z
A superconducting magnetic coil includes a plurality of sections positioned axially along the longitudinal axis of the coil, each section being formed of an anisotropic high temperature superconductor material wound about a longitudinal axis of the coil and having an associated critical current value that is dependent on the orientation of the magnetic field of the coil. The cross section of the superconductor, or the type of superconductor material, at sections along the axial and radial axes of the coil are changed to provide an increased critical current at those regions where the magnetic field is oriented more perpendicularly to the conductor plane, to thereby increase the critical current at these regions and to maintain an overall higher critical current of the coil.
Paris-Sud XI, Université de
-dimensionally-modulated, magnetic structure of neodymium metal B. Lebech Physics Department, Risra National Laboratory, DK-4000, is linear combinations of the terms where the parameters p,, p,, p, and 0 must be deter- mined://dx.doi.org/10.1051/jphyscol:1979503 #12;TWO-DIMENSIONALLY-MODULATED, MAGNETIC STRUCTURE OF NEODYMIUM METAL C5
Linearity -statistics 1.1B training
Linearity - statistics IPAT 1.1B training 300M training D0 resolution is evaluated using 100k single muon events (same events in all 3 plots). Red is the default 11L FTK bank trained using 300M muons on narrow beam of muons (central eta, fixed phi, high fixed pT). Using two types of training: default FTK
Shrink-Wrapping trajectories for Linear Programming
2010-05-30T23:59:59.000Z
May 30, 2010 ... In particular, we analyze the geometry of these trajectories in the ... convexity that does not rely on complex variables; in Section 3 we ..... otal observation for building Shrink-Wrapping framework for linear programming ... In applications, these three types of problems provide an extremely powerful modeling.
Numerical Linear Algebra and Optimization on Facebook
Sidorov, Nikita
Numerical Linear Algebra and Optimization on Facebook: "In a relationship" or "It's complicated indicate their "relationship status" on Facebook (!!!). (I don't need to define Facebook, right?) #12;Facebook is close to ubiquitous (1.2 billion users in March 2014). 556 million people log on to Facebook
Linear-quadratic fractional Gaussian control
Duncan, Tyrone E.; Pasik-Duncan, Bozenna
2013-01-01T23:59:59.000Z
In this paper a control problem for a linear stochastic system driven by a noise process that is an arbitrary zero mean, square integrable stochastic process with continuous sample paths and a cost functional that is quadratic in the system state...
Algebra Linear -Exercicios resolvidos Exercicio 1
Dias, Esmeralda Sousa
´Algebra Linear - Exerc´icios resolvidos Exerc´icio 1: Sejam E = L({(1, 1, 1), (1, 2, 2)}) e F = L~ao de E F ´e 1. Exerc´icio 2: No espa¸co dos polin´omios reais de grau menor ou igual a 3, P3
Development of a Novel Linear Magnetostrictive Actuator
Sadighi, Ali
2010-10-12T23:59:59.000Z
. ............................................................. 11 Fig. 1.9. Photograph of the extended-range linear magnetostrictive actuator with double-sided three-phase stators. ............................................................................ 12 Fig. 2.1. The overall design process...-D Slab ..........................................................................................39 3.2.2 Stator...........................................................................................................41 ix Page 3.3 Winding...
STANFORD LINEAR ACCELERATOR CENTER DIRECTOR'S OFFICE
Wechsler, Risa H.
of these offices not listed here. PART 1: RESEARCH & DEVELOPMENT PROGRAM MANAGEMENT RECORDS R&D Program Management records document the basis for research and development program management decisions, direction, policiesSTANFORD LINEAR ACCELERATOR CENTER DIRECTOR'S OFFICE RECORDS CONTROL SCHEDULE SCOPE: This schedule
SME0141 lgebra Linear e Equaes Diferenciais
Spreafico, Mauro - Instituto de Ciências Matemáticas e de Computação, Universidade de São Paulo
SME0141 Álgebra Linear e Equações Diferenciais Aula 5 Maria Luísa Bambozzi de Oliveira marialuisa; Propriedades; Teorema. Maria Luísa SME0141 Aula 5 #12;Equações Diferenciais Introdução Fenômenos em física químicas, etc. Maria Luísa SME0141 Aula 5 #12;Equações Diferenciais Definições Equação diferencial
Automatic tuning for linearly tunable filter
Huang, Sung-Ling
2004-09-30T23:59:59.000Z
A new tuning scheme for linearly tunable high-Q filters is proposed. The tuning method is based on using the phase information for both frequency and Q factor tuning. There is no need to find out the relationship between a filter's passband...
Linear Signal Reconstruction from Jittered Sampling
Paris-Sud XI, Université de
Linear Signal Reconstruction from Jittered Sampling Alessandro Nordio (1) , Carla jitter, which is based on the analysis of the mean square error (MSE) between the reconstructed sig- nal of digital signal reconstruction as a function of the clock jitter, number of quantization bits, signal
GENERALIZED LINEAR MODELS WITH REGULARIZATION A DISSERTATION
Hastie, Trevor
GENERALIZED LINEAR MODELS WITH REGULARIZATION A DISSERTATION SUBMITTED TO THE DEPARTMENT Park 2006 All Rights Reserved ii #12;I certify that I have read this dissertation and that, in my opinion, it is fully adequate in scope and quality as a dissertation for the degree of Doctor
Introduction to Statistical Linear Models Spring 2005
of multivariate data and in the language of matrices and vectors. Broad introduction to MATLAB/Octave, R (SSyllabus Introduction to Statistical Linear Models 960:577:01 Spring 2005 Instructor: Farid Statistical Analysis" Fifth edition, Prentice Hall, 2002. Other sources may be required and will be posted
Automatic tuning for linearly tunable filter
Huang, Sung-Ling
2004-09-30T23:59:59.000Z
A new tuning scheme for linearly tunable high-Q filters is proposed. The tuning method is based on using the phase information for both frequency and Q factor tuning. There is no need to find out the relationship between a filter's passband...
Diabetes Mellitus Glucose Prediction by Linear and
Diabetes Mellitus Glucose Prediction by Linear and Bayesian Ensemble Modeling Fredrik St was diagnosed with diabetes type 1. Being an engineer with a control and systems oriented curriculum I realized of diabetes glucose metabolism, and bringing new hope of technical solutions to support the management
Section Notes 5 Review of Linear Programming
Chen, Yiling
3 Lecture 4: Convexity, Extreme points 3 4 Lecture 5: Primal Simplex 4 5 Lecture 6: Advanced Primal (LP) is an optimization problem that involves maximizing or minimizing a linear objective function, ..., Am form a square matrix that is invertible · Span These vectors A1, ..., Am span the vector space
Controlling Wild Bodies Using Linear Temporal Logic
LaValle, Steven M.
Controlling Wild Bodies Using Linear Temporal Logic Leonardo Bobadilla Oscar Sanchez Justin or state feedback. We do this by exploiting the wild motions of very simple bodies in an environment propose to start with a "wildly behaving" body for which its precise equations of motion are unknown
Magnetic fluid flow phenomena in DC and rotating magnetic fields
Rhodes, Scott E. (Scott Edward), 1981-
2004-01-01T23:59:59.000Z
An investigation of magnetic fluid experiments and analysis is presented in three parts: a study of magnetic field induced torques in magnetorheological fluids, a characterization and quantitative measurement of properties ...
Magnetic catalysis and inverse magnetic catalysis in QCD
Niklas Mueller; Jan M. Pawlowski
2015-02-27T23:59:59.000Z
We investigate the effects of strong magnetic fields on the QCD phase structure at vanishing density by solving the gluon and quark gap equations, and by studying the dynamics of the quark scattering with the four-fermi coupling. The chiral crossover temperature as well as the chiral condensate are computed. For asymptotically large magnetic fields we find magnetic catalysis, while we find inverse magnetic catalysis for intermediate magnetic fields. Moreover, for large magnetic fields the chiral phase transition for massless quarks turns into a crossover. The underlying mechanisms are then investigated analytically within a few simplifications of the full numerical analysis. We find that a combination of gluon screening effects and the weakening of the strong coupling is responsible for the phenomenon of inverse catalysis. In turn, the magnetic catalysis at large magnetic field is already indicated by simple arguments based on dimensionality.
Magnetic nanowire based high resolution magnetic force microscope probes
Qin, Lu-Chang
-resolution magnetic force microscope probes using preformed magnetic nanowires. Nickel and cobalt nanowires produced by electrodeposition were directly assembled onto the tip of a commercial atomic force microscope cantilever
Solar receiver heliostat reflector having a linear drive and position information system
Horton, Richard H. (Schenectady, NY)
1980-01-01T23:59:59.000Z
A heliostat for a solar receiver system comprises an improved drive and control system for the heliostat reflector assembly. The heliostat reflector assembly is controllably driven in a predetermined way by a light-weight drive system so as to be angularly adjustable in both elevation and azimuth to track the sun and efficiently continuously reflect the sun's rays to a focal zone, i.e., heat receiver, which forms part of a solar energy utilization system, such as a solar energy fueled electrical power generation system. The improved drive system includes linear stepping motors which comprise low weight, low cost, electronic pulse driven components. One embodiment comprises linear stepping motors controlled by a programmed, electronic microprocessor. Another embodiment comprises a tape driven system controlled by a position control magnetic tape.
Method of Linear Invariants for description of beam dynamics of FEL undulator
A. Angelow; D. Trifonov; V. Angelov; H. Hristov
2008-05-23T23:59:59.000Z
We propose a new model for description of electrons beam dynamics in Free Electron Laser (FEL) undulator, based on the method of linear time-dependent invariants of quantum-mechanical charge particle. The magnetic field has periodic structure along the undulator. For this problem, described by time-dependent quadratic Hamiltonian, we obtain exact solution. The time-evolutions of the tree quantum fluctuations: covariance cov(q,p), var(q) and var(p) for the charge particle in this case are also determined. This research will help to optimize the FEL undulator: for example, using a 2.5 GeV linear electron accelerator it will be possible to emit radiation at 1.5 nm and shorter length. This method could be applicable also to any device with periodic structure of applied field (e.g. Tokamak, cyclic accelerators) for the case of charge non-relativistic quantum particles.
Estimation of Heavy Ion Densities From Linearly Polarized EMIC Waves At Earth
Kim, Eun-Hwa; Johnson, Jay R.; Lee, Dong-Hun
2014-02-24T23:59:59.000Z
Linearly polarized EMIC waves are expected to concentrate at the location where their wave frequency satisfies the ion-ion hybrid (IIH) resonance condition as the result of a mode conversion process. In this letter, we evaluate absorption coefficients at the IIH resonance in the Earth geosynchronous orbit for variable concentrations of helium and azimuthal and field-aligned wave numbers in dipole magnetic field. Although wave absorption occurs for a wide range of heavy ion concentration, it only occurs for a limited range of azimuthal and field-aligned wave numbers such that the IIH resonance frequency is close to, but not exactly the same as the crossover frequency. Our results suggest that, at L = 6.6, linearly polarized EMIC waves can be generated via mode conversion from the compressional waves near the crossover frequency. Consequently, the heavy ion concentration ratio can be estimated from observations of externally generated EMIC waves that have polarization.
STABILIZING SUPERVISORY CONTROL OF HYBRID SYSTEMS BASED ON PIECEWISE LINEAR
Antsaklis, Panos
STABILIZING SUPERVISORY CONTROL OF HYBRID SYSTEMS BASED ON PIECEWISE LINEAR LYAPUNOV FUNCTIONS1 Lyapunov func- tions. In particular, we consider discrete-time switched linear systems. The control problem of discrete-time piecewise linear hybrid systems is in- vestigated using piecewise linear Lyapunov functions
Controllability of Linear Systems with inner derivation on Lie Groups
Boyer, Edmond
Controllability of Linear Systems with inner derivation on Lie Groups Philippe JOUAN November 2 group of automorphisms. A control-ane system is linear if the drift is linear and the controlled vector groups are stated. The paper ends by many examples. Keywords: Lie groups; Linear systems; controllability
1. INTRODUCTION It is relatively easy to control linear systems.
Wilamowski, Bogdan Maciej
of the biggest challenges in modern control theory. While linear control system theory has been well developed1. INTRODUCTION It is relatively easy to control linear systems. Unfortunately, in practice most systems are nonlinear. Some of them can be linearized and use well developed linear control theory
Datadriven calibration of linear estimators with minimal penalties
This paper tackles the problem of selecting among several linear estimators in non parametric regression; this includes model selection for linear regression, the choice of a regularization parameter in kernel ridge classification, with linear and non linear predictors [37, 36]. A central issue common to all regularization
Data-driven calibration of linear estimators with minimal penalties
Paris-Sud XI, Université de
This paper tackles the problem of selecting among several linear estimators in non- parametric regression; this includes model selection for linear regression, the choice of a regularization parameter in kernel ridge classification, with linear and non- linear predictors [37, 36]. A central issue common to all regularization
Observability Criteria and Estimator Design for Stochastic Linear Hybrid Systems
Gummadi, Ramakrishna
. Alessandri and Coletta [5] proposed a Luenberger observer design methodology for deterministic linear hybrid
SWITCHING TIME ESTIMATION OF PIECEWISE LINEAR SYSTEMS. APPLICATION TO DIAGNOSIS
Boyer, Edmond
systems. Recently (Alessandri, 2001), Alessandri considered the case where continuous evolution is linear
A Linear Programming based Satisfiability solver using a new
Rossi, Francesca
is unsatisfiable or has a satisfying assignment, we solve a linear program. The solution of the linear program a satisfying assignment or a contradiction we solve a linear program. By the above men- tioned lemmaA Linear Programming based Satisfiability solver using a new Horn-driven search tree design Hans
APPENDIX 475 C. Some Results from Linear Algebra
Gajic, Zoran
APPENDIX 475 C. Some Results from Linear Algebra Linear algebra plays a very important role some standard and important linear algebra results. Definite Matrices Definition C.1: A square matrix of dimensions 798A@ is the space spanned by vectors B that satisfy CDBFEHG . Systems of Linear Algebraic
Compact Proof Certificates For Linear Logic Kaustuv Chaudhuri
Chaudhuri, Kaustuv
Compact Proof Certificates For Linear Logic Kaustuv Chaudhuri INRIA, France http://kaustuv.chaudhuri
Investigation into electron cloud effects in the International Linear Collider positron damping ring
Crittenden, J.A.; Conway, J.; Dugan, G.F.; Palmer, M.A.; Rubin, D.L.; Shanks, J.; Sonnad, K.G.; Boon, L.; Harkay, K.; Ishibashi, T.; Furman, M.A.; Guiducci, S.; Pivi, M.T.F.; Wang, L.; Crittenden, J.A.; Conway, J.; Dugan, G.F.; Palmer, M.A.; Rubin, D.L.; Shanks, J.; Sonnad, K.G.; Boon, L.; Harkay, K.; Ishibashi, T.; Furman, M.A.; Guiducci, S.; Pivi, M.T.F.; Wang, L.
2014-02-28T23:59:59.000Z
We report modeling results for electron cloud buildup and instability in the International Linear Collider positron damping ring. Updated optics, wiggler magnets, and vacuum chamber designs have recently been developed for the 5 GeV, 3.2-km racetrack layout. An analysis of the synchrotron radiation profile around the ring has been performed, including the effects of diffuse and specular photon scattering on the interior surfaces of the vacuum chamber. The results provide input to the cloud buildup simulations for the various magnetic field regions of the ring. The modeled cloud densities thus obtained are used in the instability threshold calculations. We conclude that the mitigation techniques employed in this model will suffice to allow operation of the damping ring at the design operational specifications
Magnetic Field Measurement System
Kulesza, Joe; Johnson, Eric; Lyndaker, Aaron; Deyhim, Alex; Waterman, Dave; Blomqvist, K. Ingvar [Advanced Design Consulting USA, 126 Ridge Road, P.O. Box 187, Lansing, NY 14882 (United States); Dunn, Jonathan Hunter [MAX-lab, SE-221 00 Lund (Sweden)
2007-01-19T23:59:59.000Z
A magnetic field measurement system was designed, built and installed at MAX Lab, Sweden for the purpose of characterizing the magnetic field produced by Insertion Devices (see Figure 1). The measurement system consists of a large granite beam roughly 2 feet square and 14 feet long that has been polished beyond laboratory grade for flatness and straightness. The granite precision coupled with the design of the carriage yielded minimum position deviations as measured at the probe tip. The Hall probe data collection and compensation technique allows exceptional resolution and range while taking data on the fly to programmable sample spacing. Additional flip coil provides field integral data.
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power Administration would likeConstitution AndControllingCool Magnetic Molecules Cool Magnetic
Measurements of the effect of a magnetic field on the transport of linear momentum in nitrogen
Larchez, Mark Edward
1968-01-01T23:59:59.000Z
torgue in the same direction. A torque in the direction opposite to this is produced by methane, et'nane, propane, butane, isobutane, 7 hydrogen, nydrogen deuteride, and ceuterium, No torque is shown by helium, argon, xenon, water vapor, carbon...
QUEEN'S DUPONT BACK PAIN STUDY Calibration of a Magnetic Tracking Device Using Locally Linear Fits
Murdoch, Duncan
point i, p is a power variable used to compensate for distance related measurement variance with a grid spacing of 40cm. 1440 data points were collected at 60 positions. For each point, the true position vector x=(x,y,z) and the true orientation At were known, and the observed position vector xo
Overview of the bump-magnet system at the LANSCE proton storage ring
Rose, C.R.; Barlow, D.B.; Blind, B.; Neri, F.; Power, J.F.; Walstrom, P.L.
1997-09-01T23:59:59.000Z
An upgrade program for increasing the stored beam current in the Proton Storage is presently under way. A part of the upgrade is the design and installation of a four-magnet beam-bumping system used for phase-space painting and minimizing interaction of the stored beam with the injection stripper foil. This paper describes the bump- magnet system including the relevant beam requirements, magnet specifications, power-cable specifications, pulsed-modulator requirements, and beam-tube eddy-current effects. The magnets are ferrite window-frame magnets with saddle windings. The series-pass pulsed modulators are programmable both in rise and fall time as well as amplitude. The peak current can be varied between 50 and 300 A. The pulsed-current rise-time is fixed at 1 ms, and the linear fall- time during which beam is injected into the ring can be varied between 0.5 and 1.5 ms.
Mansuripur, Masud
2015-01-01T23:59:59.000Z
The classical theory of electrodynamics cannot explain the existence and structure of electric and magnetic dipoles, yet it incorporates such dipoles into its fundamental equations, simply by postulating their existence and properties, just as it postulates the existence and properties of electric charges and currents. Maxwell's macroscopic equations are mathematically exact and self-consistent differential equations that relate the electromagnetic (EM) field to its sources, namely, electric charge-density $\\rho_{free}$, electric current-density $J_{free}$, polarization P, and magnetization M. At the level of Maxwell's macroscopic equations, there is no need for models of electric and magnetic dipoles. For example, whether a magnetic dipole is an Amperian current-loop or a Gilbertian pair of north and south magnetic monopoles has no effect on the solution of Maxwell's equations. Electromagnetic fields carry energy as well as linear and angular momenta, which they can exchange with material media - the seat of...
CONSTRAINING THREE-DIMENSIONAL MAGNETIC FIELD EXTRAPOLATIONS USING THE TWIN PERSPECTIVES OF STEREO
Conlon, Paul A.; Gallagher, Peter T. [Astrophysics Research Group, School of Physics, Trinity College Dublin, Dublin 2 (Ireland)
2010-05-20T23:59:59.000Z
The three-dimensional magnetic topology of a solar active region (NOAA 10956) was reconstructed using a linear force-free field extrapolation constrained using the twin perspectives of STEREO. A set of coronal field configurations was initially generated from extrapolations of the photospheric magnetic field observed by the Michelson Doppler Imager on SOHO. Using an EUV intensity-based cost function, the extrapolated field lines that were most consistent with 171 A passband images from the Extreme UltraViolet Imager on STEREO were identified. This facilitated quantitative constraints to be placed on the twist ({alpha}) of the extrapolated field lines, where {nabla} x B = {alpha}B. Using the constrained values of {alpha}, the evolution in time of twist, connectivity, and magnetic energy were then studied. A flux emergence event was found to result in significant changes in the magnetic topology and total magnetic energy of the region.
Non-linear propagation of kink waves to the solar chromosphere
Stangalini, M; Jafarzadeh, S
2015-01-01T23:59:59.000Z
Small-scale magnetic field concentrations (magnetic elements) in the quiet Sun are believed to contribute to the energy budget of the upper layers of the Sun's atmosphere, as they are observed to support a large number of MHD modes. In recent years, kink waves in magnetic elements were observed at different heights in the solar atmosphere, from the photosphere to the corona. However, the propagation of these waves has not been fully evaluated. Our aim is to investigate the propagation of kink waves in small magnetic elements in the solar atmosphere. We analysed spectropolarimetric data of high-quality and long duration of a photospheric quiet Sun region observed near the disk center with the spectropolarimeter CRISP at the Swedish Solar Telescope (SST), and complemented by simultaneous and co-spatial broad-band chromospheric observations of the same region. Our findings reveal a clear upward propagation of kink waves with frequency above $~2.6$ mHz. Moreover, the signature of a non-linear propagation process ...
The two-phase issue in the O(n) non-linear $?$-model: A Monte Carlo study
B. Alles; A. Buonanno; G. Cella
1996-08-01T23:59:59.000Z
We have performed a high statistics Monte Carlo simulation to investigate whether the two-dimensional O(n) non-linear sigma models are asymptotically free or they show a Kosterlitz- Thouless-like phase transition. We have calculated the mass gap and the magnetic susceptibility in the O(8) model with standard action and the O(3) model with Symanzik action. Our results for O(8) support the asymptotic freedom scenario.
Magnetic nanoworms Systematic Surface Engineering of Magnetic Nanoworms
Bhatia, Sangeeta
Magnetic nanoworms Systematic Surface Engineering of Magnetic Nanoworms for in vivo Tumor Targeting and Engineering Program Department of Chemistry and Biochemistry University of California, San Diego 9500 Gilman magnetic materials nanoworms peptides tumor targeting 694 ß 2009 Wiley-VCH Verlag GmbH & Co. KGa
Magnetic Coordinates for Systems with Imperfect Magnetic Surfaces
Dewar, Robert L.
Magnetic Coordinates for Systems with Imperfect Magnetic Surfaces R. L. Dewar and S. R. Hudson & Engineering, The Australian National University, Canberra, A.C.T. 0200, Australia e-mail: robert-orbits, and the surfaces are formed from a continuous one-parameter family of such orbits. Magnetic field-line flow
SU-E-J-233: A Facility for Radiobiological Experiments in a Large Magnetic Field
Carlone, M; Heaton, R; Keller, H [Princess Margaret Hospital, Toronto, ON (Canada); University of Toronto, Toronto, ON (Canada); Wouters, B [Ontario Cancer Institute, Toronto, ON (Canada); University of Toronto, Toronto, ON (Canada); Jaffray, D [Princess Margaret Hospital, Toronto, ON (Canada); Ontario Cancer Institute, Toronto, ON (Canada); University of Toronto, Toronto, ON (Canada)
2014-06-01T23:59:59.000Z
Purpose: There is considerable interest in developing medical linear accelerators with integrated image guidance by MRI. Less work has been done on the fundamental biology of cell survival in the presence of a strong magnetic field. The purpose of this work is to describe an experimental system capable of measuring cell survival response in the types of MRI-linac systems currently under development. Methods: We have integrated a cobalt irradiator with a solenoid magnet. The solenoid magnet has inner diameter of 10 cm. To enable measurement of the biological effects as a function of depth, we are utilizing the sliced gel technique, in which cells are embedded and fixed within a gelatin matrix. Irradiated cells at defined positions (sub mm resolution) can subsequently be recovered and assessed for cell survival or other biological effects. Results: The magnetic field profile in the solenoid has a peak magnetic field 36 cm below the top edge of the magnet bore and can be placed at and SAD of 100 cm. At a solenoid current of 35 A, the peak magnetic field is 0.25 T. The dose rate of the cobalt irradiator is 16 cGy/min at 100 cm SAD. EBT3 film was used to demonstrate the system functionality. It was irradiated at 1 cm depth at 100 cm SSD with a 4×4 field to 1.5 Gy in a 0.25 T magnetic field. The dose profile was similar between this film and the control exposure without magnetic field. Conclusion: Integrating a cobalt irradiator with a high field magnet is demonstrated. The magnetic field at the cobalt defining head was minimal and did not interfere with the functioning of this unit. Cell survival experiments can be reproduced exactly in the presence or absence of a magnetic field since a resistive magnet is used.
Magnetic refrigeration apparatus and method
Barclay, John A. (Los Alamos, NM); Overton, Jr., William C. (Los Alamos, NM); Stewart, Walter F. (Los Alamos, NM)
1984-01-01T23:59:59.000Z
The disclosure relates to refrigeration through magnetizing and demagnitizing a body by rotating it within a magnetic field. Internal and external heat exchange fluids and in one embodiment, a regenerator, are used.
Large Magnetization at Carbon Surfaces
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Large Magnetization at Carbon Surfaces Print From organic matter to pencil lead, carbon is a versatile element. Now, another use has been found: magnets. One would not expect pure...
Dunin-Borkowski, Rafal E.
then interactions change the energy balance of the combined magnetic state. We consider linear arrays of identical 55455-0219, United States Dunin-Borkowski, R rdb@cen.dtu.dk Technical University of Denmark, Center anisotropy on the energy balance will be presented, and the simulations will be compared with experimental
Garmestani, Hamid
of thermal conductance in a composite material assuming a linear law of mixing, and nanotubepolymerEnhancement of thermal and electrical properties of carbon nanotube polymer composites by magnetic and electrical properties of single wall carbon nanotube CNT -polymer composites are significantly enhanced
Optically Enhanced Magnetic Resonance
Suter, Dieter
, like spatial structures or molecular dynamics. While the direct excitation of nuclear spin transitions.1 Motivation The physical mechanism of nuclear magnetic resonance spectroscopy, the excitation of transitions light for polarizing the spin system or for observing its dynamics. This possibility arises from
Kirol, Lance D. (Shelly, ID)
1988-01-01T23:59:59.000Z
A rotary magnetic heat pump constructed without flow seals or segmented rotor accomplishes recuperation and regeneration by using split flow paths. Heat exchange fluid pumped through heat exchangers and returned to the heat pump splits into two flow components: one flowing counter to the rotor rotation and one flowing with the rotation.
Kirol, L.D.
1987-02-11T23:59:59.000Z
A rotary magnetic heat pump constructed without flow seals or segmented rotor accomplishes recuperation and regeneration by using split flow paths. Heat exchange fluid pumped through heat exchangers and returned to the heat pump splits into two flow components: one flowing counter to the rotor rotation and one flowing with the rotation. 5 figs.
Jackson, Jasper A. (Los Alamos, NM); Cooper, Richard K. (Los Alamos, NM)
1982-01-01T23:59:59.000Z
Means for producing a region of homogeneous magnetic field remote from the source of the field, wherein two equal field sources are arranged axially so their fields oppose, producing a region near the plane perpendicular to the axis midway between the sources where the radial component of the field goes through a maximum. Near the maximum, the field is homogeneous over prescribed regions.
G. Giacomelli; L. Patrizii
2005-06-07T23:59:59.000Z
In these lecture notes we discuss the status of the searches for classical Dirac Magnetic Monopoles (MMs) at accelerators, for GUT superheavy MMs in the penetrating cosmic radiation and for Intermediate Mass MMs. Also the searches for nuclearites and Q-balls are considered.
Magnetic refrigeration for spacecraft systems
Barclay, J.A.
1981-01-01T23:59:59.000Z
Magnetic refrigerators, i.e., those that use the magnetocaloric effect of a magnetic working material in a thermodynamic cycle, offer potentially reliable, and efficient refrigeration over a variety of temperature ranges and cooling powers. A descriptive analysis of magnetic refrigeration systems is performed with particular emphasis on more efficient infrared detector cooling. Three types of magnetic refrigerator designs are introduced to illustrate some of the possibilities.
Ames Lab 101: Magnetic Refrigeration
Pecharsky, Vitalij
2013-03-01T23:59:59.000Z
Vitalij Pecharsky, distinguished professor of materials science and engineering, discusses his research in magnetic refrigeration at Ames Lab.
Ames Lab 101: Magnetic Refrigeration
Pecharsky, Vitalij
2011-01-01T23:59:59.000Z
Vitalij Pecharsky, distinguished professor of materials science and engineering, discusses his research in magnetic refrigeration at Ames Lab.
Magnetic reconnection in nontoroidal plasmas
Boozer, Allen H. [Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 (United States)
2005-07-15T23:59:59.000Z
Magnetic reconnection is a major issue in solar and astrophysical plasmas. The mathematical result that the evolution of a magnetic field with only point nulls is always locally ideal limits the nature of reconnection in nontoroidal plasmas. Here it is shown that the exponentially increasing separation of neighboring magnetic field lines, which is generic, tends to produce rapid magnetic reconnection if the length of the field lines is greater than about 20 times the exponentiation, or Lyapunov, length.
Electrostatic waves in carbon nanotubes with an axial magnetic field
Abdikian, Alireza [Department of Physics, Malayer University, Malayer 65719-95863 (Iran, Islamic Republic of)] [Department of Physics, Malayer University, Malayer 65719-95863 (Iran, Islamic Republic of); Bagheri, Mehran [Laser and Plasma Research Institute, Shahid Beheshti University, G. C., Evin, Tehran 19835-63113 (Iran, Islamic Republic of)] [Laser and Plasma Research Institute, Shahid Beheshti University, G. C., Evin, Tehran 19835-63113 (Iran, Islamic Republic of)
2013-10-15T23:59:59.000Z
Based on a linearized hydrodynamic model and within the quasi-static approximation, the dispersion relation of electrostatic waves propagating through single-walled carbon nanotubes subject to an axial magnetic field is theoretically explored. In the classical limit, we obtain two main possible waves which in turn are divided into two branches, a low-frequency acoustical and a high-frequency optical plasmon branch. In the quantum case, we have found that the dispersion relation is substantially modified when the electron wavelength becomes large enough compared to the propagation wavelength of the electrostatic waves in the quantum plasma. We also show that the axial magnetic field manifest itself on the perturbed electron density through the quantum term and gives rise to the propagation of the electrostatic waves within the quantum plasma. As a result, the effect of the magnetic field is pronounced in the plasma dispersion relations in such a way that their curves approach to zero when the magnetic field is weak; and for the strong magnetic field, they asymptotically meet the constant lines.
Future Directions for Magnetic Sensors
and Engineering Laboratory Magnetic tunnel junction (MTJ) sensors are rapidly becoming the technology of choiceFuture Directions for Magnetic Sensors: HYBRIDMATERIALS Our goal is to develop the scientific expertise needed to allow modeling and simulation to become the driving force in improving magnetic sensors
Weston, Ken
at the Magnet Lab like? Often, it's about solving problems. That's what engineers Scott Bole and Lee Marks didRobotics Club! page 16 Using magnets to analyze oil page 28 #12;editor's note What's a typical day recently. Their story began when Lee noticed something odd going on during a magnet-building project: When
LABORATORY VI ELECTRICITY FROM MAGNETISM
Minnesota, University of
LABORATORY VI ELECTRICITY FROM MAGNETISM Lab VI - 1 In the previous problems you explored the magnetic field and its effect on moving charges. You also saw how electric currents could create magnetic can give rise to electric currents. This is the effect that allows the generation of electricity
Enlarge Image Peer pressure. Magnetic
Thywissen, Joseph
to stick it to your refrigerator, but an ultra-cold gas magnetizes itself just as do metals such as ironEnlarge Image Peer pressure. Magnetic domains in steel (vertical bans) arise when neighboring electrons point their magnetic poles in the same direction. CREDIT: ZUREKS, CHRIS VARDON
Low-temperature magnetic refrigerator
Barclay, J.A.
1983-05-26T23:59:59.000Z
The invention relates to magnetic refrigeration and more particularly to low temperature refrigeration between about 4 and about 20 K, with an apparatus and method utilizing a belt of magnetic material passed in and out of a magnetic field with heat exchangers within and outside the field operably disposed to accomplish refrigeration.
Low-temperature magnetic refrigerator
Barclay, John A. (Los Alamos, NM)
1985-01-01T23:59:59.000Z
The disclosure is directed to a low temperature 4 to 20 K. refrigeration apparatus and method utilizing a ring of magnetic material moving through a magnetic field. Heat exchange is accomplished in and out of the magnetic field to appropriately utilize the device to execute Carnot and Stirling cycles.
Low field magnetic resonance imaging
Pines, Alexander (Berkeley, CA); Sakellariou, Dimitrios (Billancourt, FR); Meriles, Carlos A. (Fort Lee, NJ); Trabesinger, Andreas H. (London, GB)
2010-07-13T23:59:59.000Z
A method and system of magnetic resonance imaging does not need a large homogenous field to truncate a gradient field. Spatial information is encoded into the spin magnetization by allowing the magnetization to evolve in a non-truncated gradient field and inducing a set of 180 degree rotations prior to signal acquisition.
Towards a Future Linear Collider and The Linear Collider Studies at CERN
None
2011-10-06T23:59:59.000Z
During the week 18-22 October, more than 400 physicists will meet at CERN and in the CICG (International Conference Centre Geneva) to review the global progress towards a future linear collider. The 2010 International Workshop on Linear Colliders will study the physics, detectors and accelerator complex of a linear collider covering both the CLIC and ILC options. Among the topics presented and discussed will be the progress towards the CLIC Conceptual Design Report in 2011, the ILC Technical Design Report in 2012, physics and detector studies linked to these reports, and an increasing numbers of common working group activities. The seminar will give an overview of these topics and also CERN?s linear collider studies, focusing on current activities and initial plans for the period 2011-16. n.b: The Council Chamber is also reserved for this colloquium with a live transmission from the Main Auditorium.
Nimbalkar, Manoj; Neves, Jorge L; Elavarasi, S Begam; Yuan, Haidong; Khaneja, Navin; Dorai, Kavita; Glaser, Steffen J
2011-01-01T23:59:59.000Z
We study multiple-spin coherence transfers in linear Ising spin chains with nearest neighbor couplings. These constitute a model for efficient information transfers in future quantum computing devices and for many multi-dimensional experiments for the assignment of complex spectra in nuclear magnetic resonance spectroscopy. We complement prior analytic techniques for multiple-spin coherence transfers with a systematic numerical study where we obtain strong evidence that a certain analytically-motivated family of restricted controls is sufficient for time-optimality. In the case of a linear three-spin system, additional evidence suggests that prior analytic pulse sequences using this family of restricted controls are time-optimal even for arbitrary local controls. In addition, we compare the pulse sequences for linear Ising spin chains to pulse sequences for more realistic spin systems with additional long-range couplings between non-adjacent spins. We experimentally implement the derived pulse sequences in th...
Partially linear models with unit roots
Juhl, Ted P.; Xiao, Z. J.
2005-10-01T23:59:59.000Z
~y tH110021 * H11002 [y tH110021 * !~e t H11002 [e t H11001g~x t !H11002 [g~x t !! Zf t 2 H11001o p ~1!+ PARTIALLY LINEAR MODELS WITH UNIT ROOTS 897 The theorem holds because 1 N 2 ( tH110051 N ~y tH110021 * H11002 [y tH110021 * ! 2 Zf t 2 nE~f 2 !s v... in econometrics+ One type of these models is the following partially linear regression: y t H11005g ' z t H11001g~x t !H11001e t , tH110051,+++,N, (1.1) where g~{! is an unknown real function and g is the vector of unknown param- eters that we want to estimate...
Linear tailored gain broad area semiconductor lasers
Lindsey, C.P.; Mehuys, D.; Yariv, A.
1987-06-01T23:59:59.000Z
Tailored gain semiconductor lasers capable of high-power operation with single-lobed, nearly diffraction limited beamwidths only a few degrees wide have been demonstrated in proton implanted chirped arrays and ''halftone'' broad area lasers. The authors analyze lasers with a linear gain gradient, and obtain analytic approximations for their unsaturated optical eigenmodes. Unlike a uniform array, the fundamental mode of a linear tailored gain laser is the mode at threshold. Mode discrimination may be controlled by lasing the spatial gain gradient. All modes of asymmetric tailored gain waveguides have single-lobed far-field patterns offset from 0/sup 0/. Finally, they utilize tailored gain broad area lasers to make a measurement of the antiguiding parameter, and find b = 2.5 +- 0.5, in agreement with previous results.
KWIC Index for Numerical Linear Algebra
Carpenter, J.A.
1983-07-01T23:59:59.000Z
This report is a sequel to ORNL/CSD-106 in the ongoing supplements to Professor A.S. Householder's KWIC Index for Numerical Algebra. Beginning with the previous supplement, the subject has been restricted to Numerical Linear Algebra, roughly characterized by the American Mathematical Society's classification sections 15 and 65F but with little coverage of infinite matrices, matrices over fields of characteristics other than zero, operator theory, optimization and those parts of matrix theory primarily combinatorial in nature. Some consideration is given to the uses of graph theory in Numerical Linear Algebra, particularly with respect to algorithms for sparse matrix computations. The period covered by this report is roughly the calendar year 1982 as measured by the appearance of the articles in the American Mathematical Society's Contents of Mathematical Publications lagging actual appearance dates by up to nearly half a year. The review citations are limited to the Mathematical Reviews (MR).
An LED pulser for measuring photomultiplier linearity
Friend, M; Quinn, B
2011-01-01T23:59:59.000Z
A light-emitting diode (LED) pulser for testing the low-rate response of a photomultiplier tube (PMT) to scintillator-like pulses has been designed, developed, and implemented. This pulser is intended to simulate 80 ns full width at half maximum photon pulses over the dynamic range of the PMT, in order to precisely determine PMT linearity. This particular design has the advantage that, unlike many LED test rigs, it does not require the use of multiple calibrated LEDs, making it insensitive to LED gain drifts. Instead, a finite-difference measurement is made using two LEDs which need not be calibrated with respect to one another. These measurements give a better than 1% mapping of the response function, allowing for the testing and development of particularly linear PMT bases.
Enhanced dielectric-wall linear accelerator
Sampayan, S.E.; Caporaso, G.J.; Kirbie, H.C.
1998-09-22T23:59:59.000Z
A dielectric-wall linear accelerator is enhanced by a high-voltage, fast e-time switch that includes a pair of electrodes between which are laminated alternating layers of isolated conductors and insulators. A high voltage is placed between the electrodes sufficient to stress the voltage breakdown of the insulator on command. A light trigger, such as a laser, is focused along at least one line along the edge surface of the laminated alternating layers of isolated conductors and insulators extending between the electrodes. The laser is energized to initiate a surface breakdown by a fluence of photons, thus causing the electrical switch to close very promptly. Such insulators and lasers are incorporated in a dielectric wall linear accelerator with Blumlein modules, and phasing is controlled by adjusting the length of fiber optic cables that carry the laser light to the insulator surface. 6 figs.
Linear source approximation in CASMO5
Ferrer, R.; Rhodes, J. [Studsvik Scandpower, Inc., 504 Shoup Ave., Idaho Falls, ID 83402 (United States); Smith, K. [Dept. of Nuclear Science and Engineering, Massachusetts Inst. of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139 (United States)
2012-07-01T23:59:59.000Z
A Linear Source (LS) approximation has been implemented in the two-dimensional Method of Characteristics (MOC) transport solver in a prototype version of CASMO5. The LS approximation, which relies on the computation of trajectory-based spatial moments over source regions to obtain the linear source expansion coefficients, improves the solution accuracy relative to the 'flat' or constant source approximation. In addition, the LS formulation is capable of treating arbitrarily-shaped source regions and is compatible with standard Coarse-Mesh Finite Difference (CMFD) acceleration. Numerical tests presented in this paper for the C5G7 MOX benchmark show that, for comparable accuracy with respect to the reference solution, the LS approximation can reduce the run time by a factor of four and the memory requirements by a factor often relative to the FS scheme. (authors)
The Next Linear Collider: NLC2001
D. Burke et al.
2002-01-14T23:59:59.000Z
Recent studies in elementary particle physics have made the need for an e{sup +}e{sup -} linear collider able to reach energies of 500 GeV and above with high luminosity more compelling than ever [1]. Observations and measurements completed in the last five years at the SLC (SLAC), LEP (CERN), and the Tevatron (FNAL) can be explained only by the existence of at least one particle or interaction that has not yet been directly observed in experiment. The Higgs boson of the Standard Model could be that particle. The data point strongly to a mass for the Higgs boson that is just beyond the reach of existing colliders. This brings great urgency and excitement to the potential for discovery at the upgraded Tevatron early in this decade, and almost assures that later experiments at the LHC will find new physics. But the next generation of experiments to be mounted by the world-wide particle physics community must not only find this new physics, they must find out what it is. These experiments must also define the next important threshold in energy. The need is to understand physics at the TeV energy scale as well as the physics at the 100-GeV energy scale is now understood. This will require both the LHC and a companion linear electron-positron collider. A first Zeroth-Order Design Report (ZDR) [2] for a second-generation electron-positron linear collider, the Next Linear Collider (NLC), was published five years ago. The NLC design is based on a high-frequency room-temperature rf accelerator. Its goal is exploration of elementary particle physics at the TeV center-of-mass energy, while learning how to design and build colliders at still higher energies. Many advances in accelerator technologies and improvements in the design of the NLC have been made since 1996. This Report is a brief update of the ZDR.
Generative Story Worlds Linear Logic Programs
Goldstein, Seth Copen
with standard logical implication: buy_soda : has(Alice, $1) ^ wants(Alice, soda) has(Alice, soda) #12;LINEAR LOGIC 13 A -o B #12;14 buy_soda : has(Alice, $1) * wants(Alice, soda) -o has(Alice, soda) #12;15 A * B/murder : anger C C' * anger C C' * anger C C' * anger C C' * at C L * at C' L * has C weapon -o {at C L * !dead C
REDUCTION OF COMPRESSIBILITY AND PARALLEL TRANSFER BY LANDAU DAMPING IN TURBULENT MAGNETIZED PLASMAS
Hunana, P.; Laveder, D.; Passot, T.; Sulem, P. L. [Universite de Nice Sophia Antipolis, CNRS, Observatoire de la Cote d'Azur, BP 4229 06304, Nice Cedex 4 (France); Borgogno, D., E-mail: peter.hunana@nasa.gov [Dipartimento di Energetica, Politecnico di Torino, corso Duca degli Abruzzi 24, 10138 Torino (Italy)
2011-12-20T23:59:59.000Z
Three-dimensional numerical simulations of decaying turbulence in a magnetized plasma are performed using a so-called finite Larmor radius (FLR)-Landau fluid model which incorporates linear Landau damping and FLR corrections. It is shown that compared to simulations of compressible Hall-MHD, linear Landau damping is responsible for significant damping of magnetosonic waves, which is consistent with the linear kinetic theory. Compressibility of the fluid and parallel energy cascade along the ambient magnetic field are also significantly inhibited when the beta parameter is not too small. In contrast with Hall-MHD, the FLR-Landau fluid model can therefore correctly describe turbulence in collisionless plasmas such as solar wind, providing an interpretation for its nearly incompressible behavior.
Magnetic field control of the intraband optical absorption in two-dimensional quantum rings
Olendski, O., E-mail: oolendski@ksu.edu.sa [King Abdullah Institute for Nanotechnology, King Saud University, P.O. Box 2454, Riyadh 11451 (Saudi Arabia); Barakat, T., E-mail: tbarakat@ksu.edu.sa [Department of Physics, King Saud University, P.O. Box 2454, Riyadh 11451 (Saudi Arabia)
2014-02-28T23:59:59.000Z
Linear and nonlinear optical absorption coefficients of the two-dimensional semiconductor ring in the perpendicular magnetic field B are calculated within independent electron approximation. Characteristic feature of the energy spectrum are crossings of the levels with adjacent nonpositive magnetic quantum numbers as the intensity B changes. It is shown that the absorption coefficient of the associated optical transition is drastically decreased at the fields corresponding to the crossing. Proposed model of the Volcano disc allows to get simple mathematical analytical results, which provide clear physical interpretation. An interplay between positive linear and intensity-dependent negative cubic absorption coefficients is discussed; in particular, critical light intensity at which additional resonances appear in the total absorption dependence on the light frequency is calculated as a function of the magnetic field and levels' broadening.
Tunnel current across linear homocatenated germanium chains
Matsuura, Yukihito, E-mail: matsuura@chem.nara-k.ac.jp [Department of Chemical Engineering, Nara National College of Technology Yatacho 22, Yamato-koriyama, Nara 539-1080 (Japan)
2014-01-28T23:59:59.000Z
The electronic transport properties of germanium oligomers catenating into linear chains (linear Ge chains) have been theoretically studied using first principle methods. The conduction mechanism of a Ge chain sandwiched between gold electrodes was analyzed based on the density of states and the eigenstates of the molecule in a two-probe environment. Like that of silicon chains (Si chains), the highest occupied molecular orbital of Ge chains contains the extended ?-conjugation of Ge 4p orbitals at energy levels close to the Fermi level; this is in contrast to the electronic properties of linear carbon chains. Furthermore, the conductance of a Ge chain is expected to decrease exponentially with molecular length L. The decay constant ?, which is defined as e{sup ??L}, of a Ge chain is similar to that of a Si chain, whereas the conductance of the Ge chains is higher than that of Si chains even though the Ge–Ge bond length is longer than the Si–Si bond length.
Aleks Kleyn
2015-05-08T23:59:59.000Z
Module is effective representation of ring in Abelian group. Linear map of module over commutative ring is morphism of corresponding representation. This definition is the main subject of the book. To consider this definition from more general point of view I started the book from consideration of Cartesian product of representations. Polymorphism of representations is a map of Cartesian product of representations which is a morphism of representations with respect to each separate independent variable. Reduced morphism of representations allows us to simplify the study of morphisms of representations. However a representation has to satisfy specific requirements for existence of reduced polymomorphism of representations. It is possible that Abelian group is only $\\Omega$-algebra, such that representation in this algebra admits polymorphism of representations. However, today, this statement has not been proved. Multiplicative $\\Omega$-group is $\\Omega$-algebra in which product is defined. The definition of tensor product of representations of Abelian multiplicative $\\Omega$-group is based on properties of reduced polymorphism of representations of Abelian multiplicative $\\Omega$-group. Since an algebra is a module in which the product is defined, then we can use this theory to study linear map of algebra. For instance, we can study the set of linear transformations of $D$-algebra $A$ as representation of algebra $A\\otimes A$ in algebra $A$.
Magnetoresistance and magnetic ordering in praseodymium and neodymium hexaborides
Anisimov, M. A. [Moscow Institute of Physics and Technology (State University) (Russian Federation); Bogach, A. V. [Russian Academy of Sciences, A. M. Prokhorov General Physics Institute (Russian Federation); Glushkov, V. V. [Moscow Institute of Physics and Technology (State University) (Russian Federation); Demishev, S. V.; Samarin, N. A. [Russian Academy of Sciences, A. M. Prokhorov General Physics Institute (Russian Federation); Filipov, V. B.; Shitsevalova, N. Yu. [National Academy of Sciences of Ukraine, I. N. Frantsevich Institute for Problems of Materials Science (Ukraine); Kuznetsov, A. V.; Sluchanko, N. E., E-mail: nes@lt.gpi.r [Russian Academy of Sciences, A. M. Prokhorov General Physics Institute (Russian Federation)
2009-11-15T23:59:59.000Z
The magnetoresistance {Delta}{rho}/{rho} of single-crystal samples of praseodymium and neodymium hexaborides (PrB{sub 6} and NdB{sub 6}) has been measured at temperatures ranging from 2 to 20 K in a magnetic field of up to 80 kOe. The results obtained have revealed a crossover of the regime from a small negative magnetoresistance in the paramagnetic state to a large positive magnetoresistive effect in magnetically ordered phases of the PrB{sub 6} and NdB{sub 6} compounds. An analysis of the dependences {Delta}{rho}(H)/{rho} has made it possible to separate three contributions to the magnetoresistance for the compounds under investigation. In addition to the main negative contribution, which is quadratic in the magnetic field (-{Delta}{rho}/{rho} {proportional_to} H{sup 2}), a linear positive contribution ({Delta}{rho}/{rho} {proportional_to} H) and a nonlinear ferromagnetic contribution have been found. Upon transition to a magnetically ordered state, the linear positive component in the magnetoresistance of the PrB{sub 6} and NdB{sub 6} compounds becomes dominant, whereas the quadratic contribution to the negative magnetoresistance is completely suppressed in the commensurate magnetic phase of these compounds. The presence of several components in the magnetoresistance has been explained by assuming that, in the antiferromagnetic phases of PrB{sub 6} and NdB{sub 6}, ferromagnetic nanoregions (ferrons) are formed in the 5d band in the vicinity of the rareearth ions. The origin of the quadratic contribution to the negative magnetoresistance is interpreted in terms of the Yosida model, which takes into account scattering of conduction electrons by localized magnetic moments of rare-earth ions. Within the approach used, the local magnetic susceptibility {chi}{sub loc} has been estimated. It has been demonstrated that, in the temperature range T{sub N} < T < 20 K, the behavior of the local magnetic susceptibility {chi}{sub loc} for the compounds under investigation can be described with good accuracy by the Curie-Weiss dependence {chi}{sub loc} {proportional_to} (T - {Theta}{sub p}){sup -1}.
Method of making permanent magnets
McCallum, R.W.; Dennis, K.W.; Lograsso, B.K.; Anderson, I.E.
1993-09-07T23:59:59.000Z
A method for making an isotropic permanent magnet comprises atomizing a melt of a rare earth-transition metal alloy (e.g., an Nd--Fe--B alloy enriched in Nd and B) under conditions to produce protectively coated, rapidly solidified, generally spherical alloy particles. Wherein a majority of the particles are produced/size classified within a given size fraction (e.g., 5 to 40 microns diameter) exhibiting optimum as-atomized magnetic properties and subjecting the particles to concurrent elevated temperature and elevated isotropic pressure for a time effective to yield a densified, magnetically isotropic magnet compact having enhanced magnetic properties and mechanical properties. 13 figures.
Magnetic Edge States in Graphene
Gabriela Murguia
2010-08-29T23:59:59.000Z
Magnetic confinement in graphene has been of recent and growing interest because its potential applications in nanotechnology. In particular, the observation of the so called magnetic edge states in graphene has opened the possibility to deepen into the generation of spin currents and its applications in spintronics. We study the magnetic edge states of quasi-particles arising in graphene monolayers due to an inhomogeneous magnetic field of a magnetic barrier in the formalism of the two-dimensional massless Dirac equation. We also show how the solutions of such states in each of both triangular sublattices of the graphene are related through a supersymmetric transformation in the quantum mechanical sense.
Fast superconducting magnetic field switch
Goren, Yehuda (Mountain View, CA); Mahale, Narayan K. (The Woodlands, TX)
1996-01-01T23:59:59.000Z
The superconducting magnetic switch or fast kicker magnet is employed with electron stream or a bunch of electrons to rapidly change the direction of flow of the electron stream or bunch of electrons. The apparatus employs a beam tube which is coated with a film of superconducting material. The tube is cooled to a temperature below the superconducting transition temperature and is subjected to a constant magnetic field which is produced by an external dc magnet. The magnetic field produced by the dc magnet is less than the critical field for the superconducting material, thus, creating a Meissner Effect condition. A controllable fast electromagnet is used to provide a magnetic field which supplements that of the dc magnet so that when the fast magnet is energized the combined magnetic field is now greater that the critical field and the superconducting material returns to its normal state allowing the magnetic field to penetrate the tube. This produces an internal field which effects the direction of motion and of the electron stream or electron bunch. The switch can also operate as a switching mechanism for charged particles.
Linear Collider Physics Resource Book Snowmass 2001
Ronan (Editor), M.T.
2001-06-01T23:59:59.000Z
The American particle physics community can look forward to a well-conceived and vital program of experimentation for the next ten years, using both colliders and fixed target beams to study a wide variety of pressing questions. Beyond 2010, these programs will be reaching the end of their expected lives. The CERN LHC will provide an experimental program of the first importance. But beyond the LHC, the American community needs a coherent plan. The Snowmass 2001 Workshop and the deliberations of the HEPAP subpanel offer a rare opportunity to engage the full community in planning our future for the next decade or more. A major accelerator project requires a decade from the beginning of an engineering design to the receipt of the first data. So it is now time to decide whether to begin a new accelerator project that will operate in the years soon after 2010. We believe that the world high-energy physics community needs such a project. With the great promise of discovery in physics at the next energy scale, and with the opportunity for the uncovering of profound insights, we cannot allow our field to contract to a single experimental program at a single laboratory in the world. We believe that an e{sup +}e{sup -} linear collider is an excellent choice for the next major project in high-energy physics. Applying experimental techniques very different from those used at hadron colliders, an e{sup +}e{sup -} linear collider will allow us to build on the discoveries made at the Tevatron and the LHC, and to add a level of precision and clarity that will be necessary to understand the physics of the next energy scale. It is not necessary to anticipate specific results from the hadron collider programs to argue for constructing an e{sup +}e{sup -} linear collider; in any scenario that is now discussed, physics will benefit from the new information that e{sup +}e{sup -} experiments can provide. This last point merits further emphasis. If a new accelerator could be designed and built in a few years, it would make sense to wait for the results of each accelerator before planning the next one. Thus, we would wait for the results from the Tevatron before planning the LHC experiments, and wait for the LHC before planning any later stage. In reality accelerators require a long time to construct, and they require such specialized resources and human talent that delay can cripple what would be promising opportunities. In any event, we believe that the case for the linear collider is so compelling and robust that we can justify this facility on the basis of our current knowledge, even before the Tevatron and LHC experiments are done. The physics prospects for the linear collider have been studied intensively for more than a decade, and arguments for the importance of its experimental program have been developed from many different points of view. This book provides an introduction and a guide to this literature. We hope that it will allow physicists new to the consideration of linear collider physics to start from their own personal perspectives and develop their own assessments of the opportunities afforded by a linear collider.
Transient magnetic field and temperature modeling in large magnet applications
Gurol, H.; Hardy, G.E.; Peck, S.D.; Leung, E. (General Dynamics Corp., San Diego, CA (USA). Space Systems Div.)
1989-07-01T23:59:59.000Z
This paper discusses a coupled magnetic/thermal model developed to study heat and magnetic field diffusion in conducting materials subject to time-varying external fields. There are numerous applications, both military and commercial. These include: energy storage devices, pulsed power transformers, and electromagnetic launchers. The time scales of interest may range from a magnetic field pulse of a microsecond in an electromagnetic launcher, to hundreds of seconds in an energy storage magnet. The problem can be dominated by either the magnetic field or heat diffusion, depending on the temperature and the material properties of the conductor. In general, heat diffuses much more rapidly in high electrical conductivity materials of cryogenic temperatures. The magnetic field takes longer to diffuse, since screening currents can be rapidly set up which shield the interior of the material from further magnetic field penetration. Conversely, in high resistivity materials, the magnetic field diffuses much more rapidly. A coupled two-dimensional thermal/magnetic model has been developed. The results of this model, showing the time and spatial variation of the magnetic field and temperature, are discussed for the projectile of an electromagnetic launcher.
Magnetic shielding design analysis
Kerns, J.A.; LaPaz, A.D.; Fabyan, J.
1983-12-27T23:59:59.000Z
Two passive magnetic-shielding-design approaches for static external fields are reviewed. The first approach uses the shielding solutions for spheres and cylinders while the second approach requires solving Maxwell's equations. Experimental data taken at LLNL are compared with the results from these shieldings-design methods, and improvements are recommended for the second method. Design considerations are discussed here along with the importance of material gaps in the shield.
Green, M.A.
2011-01-01T23:59:59.000Z
magnetization of the superconductor in the long correctorsMultipoles Generated by Superconductor Magnetization WithinMULTIPOLES GENERATED BY SUPERCONDUCTOR MAGNETIZATION WITHIN
Lifted Linear Programming Martin Mladenov Babak Ahmadi Kristian Kersting
Kersting, Kristian
Lifted Linear Programming Martin Mladenov Babak Ahmadi Kristian Kersting Knowledge Discovery Lifted inference approaches have rendered large, previously intractable probabilistic in- ference- tuitively, given a linear program (LP), we em- ploy a lifted variant of Gaussian belief propa- gation (Ga
Repetitive Control of a Novel Linear Magnetostrictive Actuator
Zhu, Ruikang
2014-08-10T23:59:59.000Z
This thesis presents the repetitive control (RC) design of a novel linear magnetostrictive actuator. A repetitive controller is developed and tested on a novel linear magnetostrictive actuator to improve the tracking accuracy of the actuator to a...
Controller Synthesis of Discrete Linear Plants Using MATTEO SLANINA
Sankaranarayanan, Sriram
Controller Synthesis of Discrete Linear Plants Using Polyhedra MATTEO SLANINA Stanford University controllers for linear discrete systems with disturbances. Given a plant description and a safety We study techniques for synthesizing synchronous controllers for affine plants with disturbances
Rotary-linear axes for high speed machining
Liebman, Michael Kevin, 1974-
2001-01-01T23:59:59.000Z
This thesis presents the design, analysis, fabrication, and control of a rotary-linear axis; this axis is a key subsystem for high speed, 5-axis machine tools intended for fabricating centimeter-scale parts. The rotary-linear ...
ac linear positioning: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
USA kimik@yonsei.ac.kr Abstract- In this paper, one linear tapered slot antenna (LTSA), backed Tentzeris, Manos 187 The Square Root Law Requires a Linear Key Andrew D. Ker...
Trajectory Optimization using Mixed-Integer Linear Programming
Trajectory Optimization using Mixed-Integer Linear Programming by Arthur George Richards Master Optimization using Mixed-Integer Linear Programming by Arthur George Richards Submitted to the Department subjected to avoidance and assignment requirements. The former include avoidance of collisions
The Focused Inverse Method for Linear Logic Kaustuv Chaudhuri
Chaudhuri, Kaustuv
The Focused Inverse Method for Linear Logic Kaustuv Chaudhuri CMU-CS-06-162 December 4, 2006 Mellon University, or any other entity. Copyright c 2006 Kaustuv Chaudhuri #12;Abstract Linear logic
Math 204 Elementary Linear Algebra Spring 2012 Instructor Amites Sarkar
Sarkar, Amites
Math 204 Elementary Linear Algebra Spring 2012 Instructor Amites Sarkar Text Linear Algebra and its and Fridays, in 216 Bond Hall. My phone number is 650 7569 and my e-mail is amites.sarkar@wwu.edu Course
Math 304 Linear Algebra Spring 2013 Instructor Amites Sarkar
Sarkar, Amites
Math 304 Linear Algebra Spring 2013 Instructor Amites Sarkar Text Linear Algebra and its, Tuesdays, Thursdays and Fridays, in 216 Bond Hall. My phone number is 650 7569 and my e-mail is amites.sarkar
Math 204 Elementary Linear Algebra Winter 2008 Instructor Amites Sarkar
Sarkar, Amites
Math 204 Elementary Linear Algebra Winter 2008 Instructor Amites Sarkar Text Linear Algebra and its Hall. My phone number is 650 7569 and my e-mail is amites.sarkar@wwu.edu #12;Course Objectives
Nemala, H.; Thakur, J. S.; Lawes, G.; Naik, R., E-mail: rnaik@wayne.edu [Department of Physics and Astronomy, Wayne State University, Detroit, Michigan 48202 (United States); Naik, V. M. [Department of Natural Sciences, University of Michigan-Dearborn, Dearborn, Michigan 48128 (United States); Vaishnava, P. P. [Department of Physics, Kettering University, Flint, Michigan 48504 (United States)
2014-07-21T23:59:59.000Z
Rate of heat generated by magnetic nanoparticles in a ferrofluid is affected by their magnetic properties, temperature, and viscosity of the carrier liquid. We have investigated temperature dependent magnetic hyperthermia in ferrofluids, consisting of dextran coated superparamagnetic Fe{sub 3}O{sub 4} nanoparticles, subjected to external magnetic fields of various frequencies (188–375 kHz) and amplitudes (140–235 Oe). Transmission electron microscopy measurements show that the nanoparticles are polydispersed with a mean diameter of 13.8?±?3.1?nm. The fitting of experimental dc magnetization data to a standard Langevin function incorporating particle size distribution yields a mean diameter of 10.6?±?1.2?nm, and a reduced saturation magnetization (?65?emu/g) compared to the bulk value of Fe{sub 3}O{sub 4} (?95?emu/g). This is due to the presence of a finite surface layer (?1?nm thickness) of non-aligned spins surrounding the ferromagnetically aligned Fe{sub 3}O{sub 4} core. We found the specific absorption rate, measured as power absorbed per gram of iron oxide nanoparticles, decreases monotonically with increasing temperature for all values of magnetic field and frequency. Using the size distribution of magnetic nanoparticles estimated from the magnetization measurements, we have fitted the specific absorption rate versus temperature data using a linear response theory and relaxation dissipation mechanisms to determine the value of magnetic anisotropy constant (28?±?2?kJ/m{sup 3}) of Fe{sub 3}O{sub 4} nanoparticles.
Microfabricated linear Paul-Straubel ion trap
Mangan, Michael A. (Albuquerque, NM); Blain, Matthew G. (Albuquerque, NM); Tigges, Chris P. (Albuquerque, NM); Linker, Kevin L. (Albuquerque, NM)
2011-04-19T23:59:59.000Z
An array of microfabricated linear Paul-Straubel ion traps can be used for mass spectrometric applications. Each ion trap comprises two parallel inner RF electrodes and two parallel outer DC control electrodes symmetric about a central trap axis and suspended over an opening in a substrate. Neighboring ion traps in the array can share a common outer DC control electrode. The ions confined transversely by an RF quadrupole electric field potential well on the ion trap axis. The array can trap a wide array of ions.
Parallel ion strings in linear multipole traps
Mathieu Marciante; Caroline Champenois; J. Pedregosa-Gutierrez; Annette Calisti; Martina Knoop
2011-03-13T23:59:59.000Z
Additional radio-frequency (rf) potentials applied to linear multipole traps create extra field nodes in the radial plane which allow one to confine single ions, or strings of ions, in totally rf field-free regions. The number of nodes depends on the order of the applied multipole potentials and their relative distance can be easily tuned by the amplitude variation of the applied voltages. Simulations using molecular dynamics show that strings of ions can be laser cooled down to the Doppler limit in all directions of space. Once cooled, organized systems can be moved with very limited heating, even if the cooling process is turned off.
Linearized Non-Minimal Higher Curvature Supergravity
Farakos, Fotis; Koutrolikos, Konstantinos
2015-01-01T23:59:59.000Z
In the framework of linearized non-minimal supergravity (20/20), we present the embedding of the $R + R^2$ model and we analyze its field spectrum. As usual, the auxiliary fields of the Einstein theory now become propagating, giving rise to additional degrees of freedom, which organize themselves into on-shell irreducible supermultiplets. By performing the analysis both in component and superspace formulations we identify the new supermultiplets. On top of the two massive chiral superfields reminiscent of the old-minimal supergravity embedding, the spectrum contains also a consistent physical, massive, vector supermultiplet and a tachyonic ghost, massive, vector supermultiplet.
Linearized Non-Minimal Higher Curvature Supergravity
Fotis Farakos; Alex Kehagias; Konstantinos Koutrolikos
2015-01-29T23:59:59.000Z
In the framework of linearized non-minimal supergravity (20/20), we present the embedding of the $R + R^2$ model and we analyze its field spectrum. As usual, the auxiliary fields of the Einstein theory now become propagating, giving rise to additional degrees of freedom, which organize themselves into on-shell irreducible supermultiplets. By performing the analysis both in component and superspace formulations we identify the new supermultiplets. On top of the two massive chiral superfields reminiscent of the old-minimal supergravity embedding, the spectrum contains also a consistent physical, massive, vector supermultiplet and a tachyonic ghost, massive, vector supermultiplet.
Cincia da Computao -IME -USP Programao linear
Mascarenhas, Walter Figueiredo
ExercÃcio 1 - Resolver o problema de programaÃ§Ã£o linear (PPL) abaixo pelo mÃ©todo SIMPLEX. Maximizar 4x1 +3x2 escolha da linha pivÃ´ durante a aplicaÃ§Ã£o do mÃ©todo simplex a um PPL, entÃ£o a soluÃ§Ã£o bÃ¡sica viÃ¡vel obtida apÃ³s este pivoteamento Ã© degenerada. Â· Quando resolvemos um PPL pelo mÃ©todo simplex, uma soluÃ§Ã£o bÃ¡sica