Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism
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Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism
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interpretation of XMLD data. Magnetism and X Rays The ancient Greeks and also the Chinese knew about strange and rare stones with the power to attract iron. Moreover, when...
Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism
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V. Socoliuc; L. B. Popescu
2014-10-09
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.
Circular dichroism of planar chiral magnetic metamaterials
Circular dichroism of planar chiral magnetic metamaterials M. Decker, M. W. Klein, and M. Wegener 78002); published March 5, 2007 We propose, fabricate, and study a double-layer chiral planar
Magnetic Dichroism Spectromicroscopy at SPEAR3
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Magnetic circular dichroism in x-ray absorption and core-level photoemission
Tobin, J.G.; Waddill, G.D.; Gouder, T.H.; Colmenares, C.A.; Pappas, D.P.
1993-03-17
Here is reported observation of magnetic circular dichroism in both x-ray absorption and core-level photoemission of ultra thin magnetic films using circularly polarized x-rays. Iron films (1--4 ML) grown on a Cu(001) substrate at 150 K and magnetized perpendicular to the surface show dramatic changes in the L{sub 2,3} branching ratio for different x-ray polarizations. For linearly-polarized x-rays perpendicular to the magnetic axis of the sample the branching ratio was 0.75. For films {ge} 2 ML, this ratio varied from 0.64 to 0.85 for photon spin parallel and anti-parallel, respectively, to the magnetic axis. This effect was observed either by changing the x-ray helicity for a fixed magnetic axis, or by reversing the magnetic axis for a fixed x-ray helicity. Our observation can be analyzed within a simple one-electron picture, if the raw branching ratios are no so that the linear value becomes statistical Furthermore, warming the films to {approximately}300 K eliminated this effect, indicating a loss of magnetization in the film over a temperature range of {approximately}30 K. Finally, reversing the relative orientation of the photon spin and the magnetic axis from parallel to anti-parallel allowed measurement of the exchange splitting of the Fe 2p and 3p core levels which were found to be 0.3 eV and 0.2 eV. respectively. These results are consistent with earlier studies, but the use of off-plane circularly-polarized x-rays from a bending magnet monochromator offers {approximately}2 orders of magnitude greater intensity than typical spin-polarization measurements. Finally, we have performed preliminary x-ray absorption studies of UFe{sub 2}, demonstrating the feasibilty of MCD measurements in 5f as well as 3d materials.
Unexpected Angular Dependence of X-Ray Magnetic Linear Dichroism
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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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorking With WIPPfinal
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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorking With WIPPfinalUnexpected Angular Dependence of X-Ray
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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effectWorking With WIPPfinalUnexpected Angular Dependence of X-RayUnexpected Angular
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Rusz, Jan; Idrobo, Juan -Carlos; Bhowmick, Somnath
2014-09-30
The calculations presented here reveal that an electron probe carrying orbital angular momentum is just a particular case of a wider class of electron beams that can be used to measure electron magnetic circular dichroism (EMCD) with atomic resolution. It is possible to obtain an EMCD signal with atomic resolution by simply breaking the symmetry of the electron probe phase front using the aberration-corrected optics of an scanning transmission electron microscope. The phase distribution of the probe depends on the magnetic symmetry and crystal structure of the sample. The calculations indicate that EMCD signals utilizing the phase of the electronmore »probe are as strong as those obtained by nanodiffraction methods.« less
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. E.; Assaf, B. A.; Sterbinsky, G. E.; Arena, D. A.; Heiman, D.
2014-12-05
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. Results indicate that the structural distortion mainly affects the Mn atoms as seen by the reduction of the magnetic moment from its predicted value.
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
2014-12-07
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)
Kanai, Shun; Tsujikawa, Masahito; Shirai, Masafumi; Miura, Yoshio; Matsukura, Fumihiro Ohno, Hideo
2014-12-01
We study the spin and orbital magnetic moments in Ta/Co{sub 0.4}Fe{sub 0.4}B{sub 0.2}/MgO by x-ray magnetic circular dichroism measurements as well as first-principles calculations, in order to clarify the origin of the perpendicular magnetic anisotropy. Both experimental and theoretical results show that orbital magnetic moment of Fe is more anisotropic than that of Co with respect to the magnetization direction. The anisotropy is larger for thinner CoFeB, indicating that Fe atoms at the interface with MgO contribute more than Co to the observed perpendicular magnetic anisotropy.
Nuclear spin circular dichroism
Vaara, Juha; Rizzo, Antonio; Kauczor, Joanna; Norman, Patrick; Coriani, Sonia
2014-04-07
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.
de la Venta, J.; Bouzas, V.; Pucci, A.; Laguna-Marco, M. A.; Haskel, D.; te Velthuis, S. G. E; Hoffmann, A.; Lal, J.; Bleuel, M.; Ruggeri, G.; de Julian Fernandez, C.; Garcia, M. A.; Univ.Complutense de Madrid; Inst. de Magnetismo Aplicado; Univ. of Pisa; Lab. di Magnetismo Molecolare
2009-01-01
X-ray magnetic circular dichroism (XMCD) and Small Angle Neutron Scattering (SANS) measurements were performed on thiol capped Au nanoparticles (NPs) embedded into polyethylene. An XMCD signal of 0.8 {center_dot} 10{sup -4} was found at the Au L{sub 3} edge of thiol capped Au NPs embedded in a polyethylene matrix for which Superconducting Quantum Interference Device (SQUID) magnetometry yielded a saturation magnetization, M{sub s}, of 0.06 emu/g{sub Au}. SANS measurements showed that the 3.2 nm average-diameter nanoparticles are 28% polydispersed, but no detectable SANS magnetic signal was found with the resolution and sensitivity accessible with the neutron experiment. A comparison with previous experiments carried out on Au NPs and multilayers, yield to different values between XMCD signals and magnetization measured by SQUID magnetometer. We discuss the origin of those differences.
de la Venta, J.; Bouzas, V.; Pucci, A.; Laguna-Marco, M. A.; Haskel, D.; Pinel, E. F.; te Velthuis, S. G. E.; Hoffmann, A.; Lal, J.; Bleuel, M.; Ruggeri, G.; de Julian, C.; Garcia, M. A.; Univ. Complutense de Madrid; Inst. de Magnetismo Aplicado UCM; Univ. Pisa; Univ. di Padova
2009-11-01
X-ray magnetic circular dichroism (XMCD) and Small Angle Neutron Scattering (SANS) measurements were performed on thiol capped Au nanoparticles (NPs) embedded into polyethylene. An XMCD signal of 0.8 {center_dot} 10{sup -4} was found at the Au L{sub 3} edge of thiol capped Au NPs embedded in a polyethylene matrix for which Superconducting Quantum Interference Device (SQUID) magnetometry yielded a saturation magnetization, M{sub s}, of 0.06 emu/g{sub Au}. SANS measurements showed that the 3.2 nm average-diameter nanoparticles are 28% polydispersed, but no detectable SANS magnetic signal was found with the resolution and sensitivity accessible with the neutron experiment. A comparison with previous experiments carried out on Au NPs and multilayers, yield to different values between XMCD signals and magnetization measured by SQUID magnetometer. We discuss the origin of those differences.
X-ray magnetic circular dichroism study of epitaxial magnetite ultrathin film on MgO(100)
Liu, W. Q.; Xu, Y. B. E-mail: rzhang@nju.edu.cn; Song, M. Y.; Lin, J. G.; Maltby, N. J.; Li, S. P.; Samant, M. G.; Parkin, S. S. P.; Bencok, P.; Steadman, Paul; Dobrynin, Alexey; Zhang, R. E-mail: rzhang@nju.edu.cn
2015-05-07
The spin and orbital magnetic moments of the Fe{sub 3}O{sub 4} epitaxial ultrathin film synthesized by plasma assisted simultaneous oxidization on MgO(100) have been studied with X-ray magnetic circular dichroism. The ultrathin film retains a rather large total magnetic moment, i.e., (2.73?±?0.15)??{sub B}/f.u., which is ?70% of that for the bulk-like Fe{sub 3}O{sub 4}. A significant unquenched orbital moment up to 0.54?±?0.05??{sub B}/f.u. was observed, which could come from the symmetry breaking at the Fe{sub 3}O{sub 4}/MgO interface. Such sizable orbital moment will add capacities to the Fe{sub 3}O{sub 4}-based spintronics devices in the magnetization reversal by the electric field.
Lee, Yongbin; Kim, Jong-Woo; Goldman, Alan I.; Harmon, Bruce N. (Iowa State)
2010-07-19
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.
X-ray magnetic circular dichroism at the U M{sub 4,5} absorption edges of UFe{sub 2}
Finazzi, M.; Sainctavit, P.; Dias, A.; Kappler, J.; Krill, G.; Sanchez, J.; Dalmas de Reotier, P.; Yaouanc, A.; Rogalev, A.; Goulon, J.
1997-02-01
We present an x-ray magnetic circular dichroism study performed at the U M{sub 4,5} edges on UFe{sub 2}, a ferromagnet with almost itinerant 5f electrons. The analysis of the branching ratio of the U M{sub 4,5} edges confirms the fact that the occupation number of the 5f states in UFe{sub 2} is lower than in other compounds where the f electrons are more localized. Magnetic circular dichroism effects are observed consistently with the presence of an orbital 5f magnetic moment which aligns parallel to the total magnetic moment. In agreement with a polarized neutron study, we find a nearly perfect cancellation of the U-5f spin and orbital magnetic moments, which results in a vanishing small total U-5f magnetic moment. Results are discussed in comparison with atomic multiplet calculations. {copyright} {ital 1997} {ital The American Physical Society}
Ground-state wave function of plutonium in PuSb as determined via x-ray magnetic circular dichroism
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Janoschek, M.; Haskel, D.; Fernandez-Rodriguez, J.; van Veenendaal, M.; Rebizant, J.; Lander, G. H.; Zhu, J. -X.; Thompson, J. D.; Bauer, E. D.
2015-01-14
Measurements of x-ray magnetic circular dichroism (XMCD) and x-ray absorption near-edge structure (XANES) spectroscopy at the Pu M?,? edges of the ferromagnet PuSb are reported. Using bulk magnetization measurements and a sum rule analysis of the XMCD spectra, we determine the individual orbital [?L = 2.8(1)?B/Pu] and spin moments [?S = –2.0(1)?B/Pu] of the Pu 5f electrons for the first time. Atomic multiplet calculations of the XMCD and XANES spectra reproduce well the experimental data and are consistent with the experimental value of the spin moment. These measurements of Lz and Sz are in excellent agreement with the values thatmore »have been extracted from neutron magnetic form factor measurements, and confirm the local character of the 5f electrons in PuSb. We demonstrate that a split M? as well as a narrow M? XMCD signal may serve as a signature of 5f electron localization in actinide compounds.« less
Ground-state wave function of plutonium in PuSb as determined via x-ray magnetic circular dichroism
Janoschek, M.; Haskel, D.; Fernandez-Rodriguez, J.; van Veenendaal, M.; Rebizant, J.; Lander, G. H.; Zhu, J. -X.; Thompson, J. D.; Bauer, E. D.
2015-01-01
Measurements of x-ray magnetic circular dichroism (XMCD) and x-ray absorption near-edge structure (XANES) spectroscopy at the Pu M?,? edges of the ferromagnet PuSb are reported. Using bulk magnetization measurements and a sum rule analysis of the XMCD spectra, we determine the individual orbital [?L = 2.8(1)?B/Pu] and spin moments [?S = ?2.0(1)?B/Pu] of the Pu 5f electrons for the first time. Atomic multiplet calculations of the XMCD and XANES spectra reproduce well the experimental data and are consistent with the experimental value of the spin moment. These measurements of ?L_{z}? and ?S_{z}? are in excellent agreement with the values that have been extracted from neutron magnetic form factor measurements, and confirm the local character of the 5f electrons in PuSb. Finally, we demonstrate that a split M? as well as a narrow M? XMCD signal may serve as a signature of 5f electron localization in actinide compounds.
Galanakis, I. [Institut de Physique et de Chimie des Materiaux de Strasbourg (IPCMS), 23 rue du Loess, 67037 Strasbourg Cedex, (France)] [Institut de Physique et de Chimie des Materiaux de Strasbourg (IPCMS), 23 rue du Loess, 67037 Strasbourg Cedex, (France); Ostanin, S. [Institut de Physique et de Chimie des Materiaux de Strasbourg (IPCMS), 23 rue du Loess, 67037 Strasbourg Cedex, (France)] [Institut de Physique et de Chimie des Materiaux de Strasbourg (IPCMS), 23 rue du Loess, 67037 Strasbourg Cedex, (France); Alouani, M. [Institut de Physique et de Chimie des Materiaux de Strasbourg (IPCMS), 23 rue du Loess, 67037 Strasbourg Cedex, (France)] [Institut de Physique et de Chimie des Materiaux de Strasbourg (IPCMS), 23 rue du Loess, 67037 Strasbourg Cedex, (France); Dreysse, H. [Institut de Physique et de Chimie des Materiaux de Strasbourg (IPCMS), 23 rue du Loess, 67037 Strasbourg Cedex, (France)] [Institut de Physique et de Chimie des Materiaux de Strasbourg (IPCMS), 23 rue du Loess, 67037 Strasbourg Cedex, (France); Wills, J. M. [Center for Materials Science and Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States)] [Center for Materials Science and Theoretical Division, Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States)
2000-01-01
A detailed theoretical study of magnetic and structural properties of Fe{sub 0.5}Pd{sub 0.5} ordered face-centered tetragonal (fct) alloy, using both the local spin density approximation (LSDA) and the generalized gradient approximation (GGA), is presented. The total energy surface as a function of the lattice parameters a and c shows a long valley where stable structures may exist. Our calculation using the GGA predicts a magnetic phase transition from perpendicular to parallel magnetization as a function of the lattice parameter, whereas LSDA favors always the [001] magnetization axis for all values of the lattice parameters. The spin and orbital magnetic moments and x-ray magnetic circular dichroism spectra are calculated for the easy [001] and the hard [100] magnetization axis and for three sets of experimental lattice parameters, and are compared to the available experimental results on these films. A supercell calculation for a 4 monolayer Fe{sub 0.5}Pd{sub 0.5} thin film produced similar results. While the spin magnetic moments are in fair agreement with experiment, the orbital magnetic moments are considerably underestimated. To improve the agreement with experiment we included an atomic orbital polarization term; however, the computed orbital moments scarcely changed. (c) 2000 The American Physical Society.
Atomic moments in Mn_{2}CoAl thin films analyzed by X-ray magnetic circular dichroism
Jamer, M. E.; Assaf, B. A.; Sterbinsky, G. E.; Arena, D. A.; Heiman, D.
2014-12-05
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. Results indicate that the structural distortion mainly affects the Mn atoms as seen by the reduction of the magnetic moment from its predicted value.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Thersleff, Thomas; Rusz, Jan; Rubino, Stefano; Hjörvarsson, Björgvin; Ito, Yasuo; J. Zaluzec, Nestor; Leifer, Klaus
2015-08-17
Understanding the ramifications of reduced crystalline symmetry on magnetic behavior is a critical step in improving our understanding of nanoscale and interfacial magnetism. However, investigations of such effects are often controversial largely due to the challenges inherent in directly correlating nanoscale stoichiometry and structure to magnetic behavior. Here, we describe how to use Transmission Electron Microscope (TEM) to obtain Electron Magnetic Circular Dichroism (EMCD) signals as a function of scattering angle to locally probe the magnetic behavior of thin oxide layers grown on an Fe (1 1 0) surface. Experiments and simulations both reveal a strong dependence of the magneticmore »orbital to spin ratio on its scattering vector in reciprocal space. We exploit this variation to extract the magnetic properties of the oxide cladding layer, showing that it locally may exhibit an enhanced orbital to spin moment ratio. This finding is supported here by both spatially and angularly resolved EMCD measurements, opening up the way for compelling investigations into how magnetic properties are affected by nanoscale features.« less
An analysis of the x-ray linear dichroism spectrum for NiO thin films grown on vicinal Ag(001)
Wu, Y.Z.
2008-01-01
dichroism spectrum for NiO thin films grown on vicinal Ag(Antiferromagnetic (AFM) NiO thin films are grown epitaxiallyXLD). We find that the NiO AFM spin exhibits an in- plane
VINETA II: A linear magnetic reconnection experiment
Bohlin, H. Von Stechow, A.; Rahbarnia, K.; Grulke, O.; Klinger, T.; Ernst-Moritz-Arndt University, Domstr. 11, 17489 Greifswald
2014-02-15
A linear experiment dedicated to the study of driven magnetic reconnection is presented. The new device (VINETA II) is suitable for investigating both collisional and near collisionless reconnection. Reconnection is achieved by externally driving magnetic field lines towards an X-point, inducing a current in the background plasma which consequently modifies the magnetic field topology. Owing to the open field line configuration of the experiment, the current is limited by the axial sheath boundary conditions. A plasma gun is used as an additional electron source in order to counterbalance the charge separation effects and supply the required current. Two drive methods are used in the device. First, an oscillating current through two parallel conductors drive the reconnection. Second, a stationary X-point topology is formed by the parallel conductors, and the drive is achieved by an oscillating current through a third conductor. In the first setup, the magnetic field of the axial plasma current dominates the field topology near the X-point throughout most of the drive. The second setup allows for the amplitude of the plasma current as well as the motion of the flux to be set independently of the X-point topology of the parallel conductors.
Hojo, H. E-mail: fujita@dipole7.kuic.kyoto-u.ac.jp; Fujita, K. E-mail: fujita@dipole7.kuic.kyoto-u.ac.jp; Matoba, T.; Tanaka, K.; Ikeno, H.; Mizoguchi, T.; Tanaka, I.; Nakamura, T.; Takeda, Y.; Okane, T.
2014-03-17
The solid solutions between ilmenite (FeTiO{sub 3}) and hematite (?-Fe{sub 2}O{sub 3}) have recently attracted considerable attention as a spintronic material due to their interesting magnetic and electrical properties. In this study, the electronic and magnetic structures of epitaxially grown 0.6FeTiO{sub 3}·0.4Fe{sub 2}O{sub 3} solid solution thin films were investigated by combining x-ray absorption near-edge structure (XANES), x-ray magnetic circular dichroism (XMCD) for two different crystallographic projections, and first-principles theoretical calculations. The Fe L-edge XANES and XMCD spectra reveal that Fe is in the mixed-valent Fe{sup 2+}–Fe{sup 3+} states while Fe{sup 2+} ions are mainly responsible for the magnetization. Moreover, the experimental Fe L-edge XANES and XMCD spectra change depending on the incident x-ray directions, and the theoretical spectra explain such spectral features. We also find a large orbital magnetic moment, which can originate the magnetic anisotropy of this system. On the other hand, although the valence state of Ti was interpreted to be 4+ from the Ti L-edge XANES, XMCD signals indicate that some electrons are present in the Ti-3d orbital, which are coupled antiparallel to the magnetic moment of Fe{sup 2+} ions.
Magnetic levitation configuration incorporating levitation, guidance and linear synchronous motor
Coffey, Howard T. (Darien, IL)
1993-01-01
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.
Magnetic levitation configuration incorporating levitation, guidance and linear synchronous motor
Coffey, H.T.
1993-10-19
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.
Circular dichroism in the electron microscope: Progress and applications (invited)
Schattschneider, P.; Loeffler, S.; Ennen, I.; Stoeger-Pollach, M.; Verbeeck, J.
2010-05-15
According to theory, x-ray magnetic circular dichroism in a synchrotron is equivalent to energy loss magnetic chiral dichroism (EMCD) in a transmission electron microscope (TEM). After a synopsis of the development of EMCD, the theoretical background is reviewed and recent results are presented, focusing on the study of magnetic nanoparticles for ferrofluids and Heusler alloys for spintronic devices. Simulated maps of the dichroic strength as a function of atom position in the crystal allow evaluating the influence of specimen thickness and sample tilt on the experimental EMCD signal. Finally, the possibility of direct observation of chiral electronic transitions with atomic resolution in a TEM is discussed.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Ueland, B. G.; Pandey, Abhishek; Lee, Y.; Sapkota, A.; Choi, Y.; Haskel, D.; Rosenberg, R. A.; Lang, J. C.; Harmon, B. N.; Johnston, D. C.; et al
2015-05-27
In this study, x-ray magnetic circular dichroism (XMCD) measurements on single-crystal and powder samples of Ba0.6K0.4Mn2As2 show that the ferromagnetism below TC ? 100 K arises in the As 4p conduction band. No XMCD signal is observed at the Mn x-ray absorption edges. Below TC, however, a clear XMCD signal is found at the As K edge which increases with decreasing temperature. The XMCD signal is absent in data taken with the beam directed parallel to the crystallographic c axis indicating that the orbital magnetic moment lies in the basal plane of the tetragonal lattice. These results show that themore »previously reported itinerant ferromagnetism is associated with the As 4p conduction band and that distinct local-moment antiferromagnetism and itinerant ferromagnetism with perpendicular easy axes coexist in this compound at low temperature.« less
One-electron linear systems in a strong magnetic field
J. C. Lopez V.; A. Turbiner
2000-01-19
Using a variational method we study a sequence of the one-electron atomic and molecular-type systems H, H_2^+, H_3^(2+) and H_4^(3+) in the presence of a homogeneous magnetic field ranging B = 0 - 4.414x10^{13} G. These systems are taken as a linear configuration aligned with the magnetic lines. For H_3^(2+) the potential energy surface has a minimum for B\\sim 10^{11} G which deepens with growth of the magnetic field strength (JETP Lett. 69, 844 (1999)); for B \\gtrsim 10^{12} G the minimum of the potential energy surface becomes sufficiently deep to have longitudinal vibrational state. We demonstrate that for the (ppppe) system the potential energy surface at B \\gtrsim 4.414x10^{13} G develops a minimum, indicating the possible existence of exotic molecular ion H_4^(3+). We find that for almost all accessible magnetic fields H_2^+ is the most bound one-electron linear system while for magnetic fields B \\gtrsim 10^{13} G the molecular ion H_3^(2+) becomes the most bound.
13th International Conference on Magnetically Levitated Systems and Linear Drives
Not Available
1993-09-01
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.
MacKinnon, Angus
Two-dimensional electron gas in a linearly varying magnetic field: Quantization of the electron of electron and current densities. We investigate the case where the magnetic field varies linearly properties of a noninteracting electron gas in a linearly varying magnetic field, we consider the following
ACTIVE SUSPENSION CONTROL WITH DIRECT-DRIVE TUBULAR LINEAR BRUSHLESS PERMANENT-MAGNET MOTOR
Lee, Seungho
2010-01-16
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...
Vibration Stabilization of a Mechanical Model of a X-Band Linear Collider Final Focus Magnet
Frisch, Josef; Chang, Allison; Decker, Valentin; Doyle, Eric; Eriksson, Leif; Hendrickson, Linda; Himel, Thomas; Markiewicz, Thomas; Partridge, Richard; Seryi, Andrei; /SLAC
2006-09-28
The small beam sizes at the interaction point of a X-band linear collider require mechanical stabilization of the final focus magnets at the nanometer level. While passive systems provide adequate performance at many potential sites, active mechanical stabilization is useful if the natural or cultural ground vibration is higher than expected. A mechanical model of a room temperature linear collider final focus magnet has been constructed and actively stabilized with an accelerometer based system.
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
Development of a Non-Magnetic Inertial Sensor for Vibration Stabilization in a Linear Collider
Frisch, Josef; Decker, Valentin; Doyle, Eric; Hendrickson, Linda; Himel, Thomas; Markiewicz, Thomas; Seryi, Andrei; /SLAC; Chang, Allison; Partridge, Richard; /Brown U.
2006-09-01
One of the options for controlling vibration of the final focus magnets in a linear collider is to use active feedback based on accelerometers. While commercial geophysics sensors have noise performance that substantially exceeds the requirements for a linear collider, they are physically large, and cannot operate in the strong magnetic field of the detector. Conventional nonmagnetic sensors have excessive noise for this application. We report on the development of a non-magnetic inertial sensor, and on a novel commercial sensor both of which have demonstrated the required noise levels for this application.
Design of magnetic mirrors for a linear theta pinch
Veglia, V. P.
1981-01-01
The problem of generating optimum magnetic mirror fields at the ends of a 50-cm long theta-pinch experiment to study particle flow and loss effects has been investigated. A combination of active and passive mirrors was developed to produce 2-3:1 fields for a 23-kG pinch. Biot-Savart and potential field prediction solutions for the magnetic field distribution were compared with experimental measurements in 2-5-cm long coils for the 50-cm long pinch.
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)
2012-06-15
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.
Melrose, Don
Quantum correction to the linear response for a magnetized electron gas D. B. Melrose and J. I. INTRODUCTION The linear response tensor for a magnetized, relativistic quantum electron gas was first magnetized electron plus positron gas reproduces its nonquantum counterpart. In the relativistic quantum case
Negative experimental evidence for magneto-orbital dichroism
Mathevet, Renaud; Pruvost, Laurence; Rikken, Geert L J A
2012-01-01
A light beam can carry both spin angular momentum (SAM) and orbital angular momentum (OAM). SAM is commonly evidenced by circular dichroism (CD) experiments i. e. differential absorption of left and right-handed circularly polarized light. Recent experiments, supported by theoretical work, indicate that the corresponding effect with OAM instead of SAM is not observed in chiral matter. Isotropic materials can show CD when subjected to a magnetic field (MCD). We report a set of experiments, under well defined conditions, searching for magnetic orbital dichroism (MOD), differential absorption of light as a function of the sign of its OAM. We experimentally demonstrate that this effect, if any, is smaller than a few 10^{-4} of MCD for the Nd:YAG ^4I_{9/2} ^4F_{5/2} transition. This transition is essentially of electric dipole nature. We give an intuitive argument suggesting that the lowest order of light matter interaction leading to MOD is the electric quadrupole term.
Spin-Induced Polarizations and Directional Dichroism of Multiferroic BiFeO3.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Fishman, Randy Scott; Lee, Jun Hee; Bordacs, S.; Kezsmarki, I.; Nagel, U.; Room, T.
2015-09-14
A microscopic model for the room-temperature multiferroic BiFeO3 that includes two Dzyaloshinskii-Moriya interactions and single-ion anisotropy along the ferroelectric polarization predicts both the zero-field spectroscopic modes as well as their splitting and evolution in a magnetic field. Due to simultaneously broken time-reversal and spatial-inversion symmetries, the absorption of light changes as the magnetic field or the direction of light propagation is reversed. We discuss three physical mechanisms that may contribute to this absorption asymmetry known as directional dichroism: the spin current, magnetostriction, and single-ion anisotropy. We conclude that the directional dichroism in BiFeO3 is dominated by the spin-current polarization andmore »is insensitive to the magnetostriction and easy-axis anisotropy. With three independent spin-current parameters, our model accurately describes the directional dichroism observed for magnetic field along [1, 1, 0]. Since some modes are almost transparent to light traveling in one direction but opaque for light traveling in the opposite direction, BiFeO3 can be used as a room-temperature optical diode at certain frequencies in the GHz to THz range. Our work demonstrates that an analysis of the directional dichroism spectra based on an effective spin model supplemented by first-principles calculations can produce a quantitative microscopic theory of the magnetoelectric couplings in multiferroic materials.« less
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)
1997-09-01
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.
Non-linear dynamics of Kelvin-Helmholtz unstable magnetized jets three-dimensional effects
Keppens, R
1999-01-01
A numerical study of the Kelvin-Helmholtz instability in compressible magnetohydrodynamics is presented. The three-dimensional simulations consider shear flow in a cylindrical jet configuration, embedded in a uniform magnetic field directed along the jet axis. The growth of linear perturbations at specified poloidal and axial mode numbers demonstrate intricate non-linear coupling effects. The physical mechanims leading to induced secondary Kelvin-Helmholtz instabilities at higher mode numbers are identified. The initially weak magnetic field becomes locally dominant in the non-linear dynamics before and during saturation. Thereby, it controls the jet deformation and eventual breakup. The results are obtained using the Versatile Advection Code [G. Toth, Astrophys. Lett. Comm. 34, 245 (1996)], a software package designed to solve general systems of conservation laws. An independent calculation of the same Kelvin-Helmholtz unstable jet configuration using a three-dimensional pseudo-spectral code gives important ...
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
2006-06-06
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.
Ueland, B. G.; Pandey, Abhishek; Lee, Y.; Sapkota, A.; Choi, Y.; Haskel, D.; Rosenberg, R. A.; Lang, J. C.; Harmon, B. N.; Johnston, D. C.; Kreyssig, A.; Goldman, A. I.
2015-05-27
In this study, x-ray magnetic circular dichroism (XMCD) measurements on single-crystal and powder samples of Ba_{0.6}K_{0.4}Mn_{2}As_{2} show that the ferromagnetism below T_{C} ? 100 K arises in the As 4p conduction band. No XMCD signal is observed at the Mn x-ray absorption edges. Below T_{C}, however, a clear XMCD signal is found at the As K edge which increases with decreasing temperature. The XMCD signal is absent in data taken with the beam directed parallel to the crystallographic c axis indicating that the orbital magnetic moment lies in the basal plane of the tetragonal lattice. These results show that the previously reported itinerant ferromagnetism is associated with the As 4p conduction band and that distinct local-moment antiferromagnetism and itinerant ferromagnetism with perpendicular easy axes coexist in this compound at low temperature.
Analytical modeling of a new disc permanent magnet linear synchronous machine for electric vehicles
Liu, C.T.; Chen, J.W.; Su, K.S.
1999-09-01
This paper develops an analytical approach based on a qd0 reference frame model to analyze dynamic and steady state characteristics of disc permanent magnet linear synchronous machines (DPMLSMs). The established compact mathematical model can be more easily employed to analyze the system behavior and to design the controller. Superiority in operational electromagnetic characteristics of the proposed DPMLSM for electric vehicle (EV) applications is verified by both numerical simulations and experimental investigations.
MULTIPASS MUON RLA RETURN ARCS BASED ON LINEAR COMBINED-FUNCTION MAGNETS
Vasiliy Morozov, Alex Bogacz, Yves Roblin, Kevin Beard
2011-09-01
Recirculating Linear Accelerators (RLA) are an efficient way of accelerating short-lived muons to the multi-GeV energies required for Neutrino Factories and TeV energies required for Muon Colliders. In this paper we present a design of a two-pass RLA return arc based on linear combined function magnets, in which both charge muons with momenta different by a factor of two are transported through the same string of magnets. The arc is composed of 60{sup o}-bending symmetric super cells allowing for a simple arc geometry closing. By adjusting the dipole and quadrupole components of the combined-function magnets, each super cell is designed to be achromatic and to have zero initial and final periodic orbit offsets for both muon momenta. Such a design provides a greater compactness than, for instance, an FFAG lattice with its regular alternating bends and is expected to possess a large dynamic aperture characteristic of linear-field lattices.
Non-linear dynamics of Kelvin-Helmholtz unstable magnetized jets: three-dimensional effects
R. Keppens; G. Toth
1999-01-27
A numerical study of the Kelvin-Helmholtz instability in compressible magnetohydrodynamics is presented. The three-dimensional simulations consider shear flow in a cylindrical jet configuration, embedded in a uniform magnetic field directed along the jet axis. The growth of linear perturbations at specified poloidal and axial mode numbers demonstrate intricate non-linear coupling effects. The physical mechanims leading to induced secondary Kelvin-Helmholtz instabilities at higher mode numbers are identified. The initially weak magnetic field becomes locally dominant in the non-linear dynamics before and during saturation. Thereby, it controls the jet deformation and eventual breakup. The results are obtained using the Versatile Advection Code [G. Toth, Astrophys. Lett. Comm. 34, 245 (1996)], a software package designed to solve general systems of conservation laws. An independent calculation of the same Kelvin-Helmholtz unstable jet configuration using a three-dimensional pseudo-spectral code gives important insights into the coupling and excitation events of the various linear mode numbers.
SU(3) Polyakov Linear Sigma-Model in an External Magnetic Field
Abdel Nasser Tawfik; Niseem Magdy
2014-06-29
In the present work, we analyse the effects of an external magnetic field on the chiral critical temperature $T_c$ of strongly interacting matter. In doing this, we can characterize the magnetic properties of the quantum chromodynamics (QCD) strong interacting matter, the quark-gluon plasma (QGP). We investigate this in the framework of the SU(3) Polyakov linear sigma-model (PLSM). To this end, we implement two approaches representing two systems, in which the Polyakov-loop potential added to PLMS either renormalized or non-normalized. The effects of Landau quantization on the strongly interacting matter is conjectures to reduce the electromagnetic interactions between quarks. In this case, the color interactions will be dominant and increasing, which - in turn - can be achieved by increasing of the Polyakov-loop fields. Obviously, each of them equips us with a different understanding about the critical temperature under the effect of an external magnetic field. In both systems, we obtain a paramagnetic response. In one system, we find that $T_c$ increases with increasing the magnetic field. In the other one, $T_c$ significantly decreases with increasing the magnetic field.
ANALYSIS OF QUIET-SUN INTERNETWORK MAGNETIC FIELDS BASED ON LINEAR POLARIZATION SIGNALS
Orozco Suarez, D.; Bellot Rubio, L. R.
2012-05-20
We present results from the analysis of Fe I 630 nm measurements of the quiet Sun taken with the spectropolarimeter of the Hinode satellite. Two data sets with noise levels of 1.2 Multiplication-Sign 10{sup -3} and 3 Multiplication-Sign 10{sup -4} are employed. We determine the distribution of field strengths and inclinations by inverting the two observations with a Milne-Eddington model atmosphere. The inversions show a predominance of weak, highly inclined fields. By means of several tests we conclude that these properties cannot be attributed to photon noise effects. To obtain the most accurate results, we focus on the 27.4% of the pixels in the second data set that have linear polarization amplitudes larger than 4.5 times the noise level. The vector magnetic field derived for these pixels is very precise because both circular and linear polarization signals are used simultaneously. The inferred field strength, inclination, and filling factor distributions agree with previous results, supporting the idea that internetwork (IN) fields are weak and very inclined, at least in about one quarter of the area occupied by the IN. These properties differ from those of network fields. The average magnetic flux density and the mean field strength derived from the 27.4% of the field of view with clear linear polarization signals are 16.3 Mx cm{sup -2} and 220 G, respectively. The ratio between the average horizontal and vertical components of the field is approximately 3.1. The IN fields do not follow an isotropic distribution of orientations.
Determination of the Fe magnetic anisotropies and the CoO frozen spins in epitaxial CoO/Fe/Ag(001)
Meng, J. Li, Y.; Park, J. S.; Jenkins, C. A.; Arenholz, E.; Scholl, A.; Tan, A.; Son, H.; Zhao, H. W.; Hwang, Chanyong; Qiu, Z. Q.
2011-04-28
CoO/Fe/Ag(001) films were grown epitaxially and studied by X-ray Magnetic Circular Dichroism (XMCD) and X-ray Magnetic Linear Dichroism (XMLD). After field cooling along the Fe[100] axis to 80 K, exchange bias, uniaxial anisotropy, and 4-fold anisotropy of the films were determined by hysteresis loop and XMCD measurements by rotating the Fe magnetization within the film plane. The CoO frozen spins were determined by XMLD measurement as a function of CoO thickness.We find that among the exchange bias, uniaxial anisotropy, and 4-fold anisotropy, only the uniaxial magnetic anisotropy follows thickness dependence of the CoO frozen spins.
Periodic permanent magnet development for linear collider X-band klystrons
Sprehn, D.; Caryotakis, G.; Jongewaard, E.; Phillips, R. [Stanford Linear Accelerator Center, Stanford University, Stanford, California 94309 (United States)
1999-05-07
The Stanford Linear Accelerator Center (SLAC) klystron group is currently designing, fabricating and testing 11.424 GHz klystrons with peak output powers from 50 to 75 MW at 1 to 2 {mu}s rf pulsewidths as part of an effort to realize components necessary for the construction of the Next Linear Collider (NLC). In order to eliminate the projected operational-year energy bill for klystron solenoids, Periodic Permanent Magnet (PPM) focusing has been employed on our latest X-band klystron designs. A PPM beam tester has operated at the same repetition rate, voltage and average beam power required for a 75-MW NLC klystron. Prototype 50 and 75-MW PPM klystrons were built and tested during 1996 and 1997 which operate from 50 to 70 MW at efficiencies greater than 55%. Construction and testing of 75-MW research klystrons will continue while the design and reliability is perfected. This paper will discuss the design of these PPM klystrons and the results of testing to date along with future plans for the development of a low-cost Design for Manufacture (DFM) 75-MW klystron and invitation for industry participation.
Periodic permanent magnet development for linear collider X-band klystrons
Sprehn, D.; Caryotakis, G.; Jongewaard, E.; Phillips, R. [Stanford Linear Accelerator Center, Stanford University, Stanford, California 94309 (United States)
1999-05-01
The Stanford Linear Accelerator Center (SLAC) klystron group is currently designing, fabricating and testing 11.424 GHz klystrons with peak output powers from 50 to 75 MW at 1 to 2 {mu}s rf pulsewidths as part of an effort to realize components necessary for the construction of the Next Linear Collider (NLC). In order to eliminate the projected operational-year energy bill for klystron solenoids, Periodic Permanent Magnet (PPM) focusing has been employed on our latest X-band klystron designs. A PPM beam tester has operated at the same repetition rate, voltage and average beam power required for a 75-MW NLC klystron. Prototype 50 and 75-MW PPM klystrons were built and tested during 1996 and 1997 which operate from 50 to 70 MW at efficiencies greater than 55{percent}. Construction and testing of 75-MW research klystrons will continue while the design and reliability is perfected. This paper will discuss the design of these PPM klystrons and the results of testing to date along with future plans for the development of a low-cost Design for Manufacture (DFM) 75-MW klystron and invitation for industry participation. {copyright} {ital 1999 American Institute of Physics.}
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)
2014-04-15
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
2007-06-27
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.
Crawford, Anthony C
2014-01-01
This note presents measurements that support the conclusion that it is feasible to achieve magnetic field values at the level of 5 milliGauss for a cryomodule in a realistic and representative ambient magnetic field environment.
Thomas Wiegelmann; Bernd Inhester; Bernhard Kliem; Gherardo Valori; Thomas Neukirch
2006-12-21
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.
Abdel Nasser Tawfik; Niseem Magdy
2015-01-06
Effects of external magnetic field on various properties of the quantum chromodynamics under extreme conditions of temperature and density have been analysed. To this end, we use SU(3) Polyakov linear sigma-model and assume that the external magnetic field eB adds some restrictions to the quarks energy due to the existence of free charges in the plasma phase. In doing this, we apply the Landau theory of quantization. This requires an additional temperature to drive the system through the chiral phase-transition. Accordingly, the dependence of the critical temperature of chiral and confinement phase-transitions on the magnetic field is characterized. Based on this, we have studied the thermal evolution of thermodynamic quantities and the first four higher-order moment of particle multiplicity. Having all these calculations, we have studied the effects of magnetic field on chiral phase-transition. We found that both critical temperature T_c and critical chemical potential increase with increasing the magnetic field eB. Last but not least, the magnetic effects of the thermal evolution of four scalar and four pseudoscalar meson states are studied. We concluded that the meson masses decrease as the temperature increases till T_c. Then, the vacuum effect becomes dominant and rapidly increases with the temperature T. At low T, the scalar meson masses normalized to the lowest Matsubara frequency rapidly decreases as T increases. Then, starting from T_c, we find that the thermal dependence almost vanishes. Furthermore, the meson masses increase with increasing magnetic field. This gives characteristic phase diagram of T vs. external magnetic field $B. At high T, we find that the masses of almost all meson states become temperature independent. It is concluded that the various meson states likely have different T_c's.
Circular dichroism in core-level emission from O/W(110): Experiment and theory
Daimon, H. [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)] [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); [Graduate School of Materials Science, Nara Institute of Science and Technology, Ikoma, Nara 630-0101 (Japan); Ynzunza, R.X.; Palomares, F.J.; Tober, E.D.; Wang, Z.X.; Kaduwela, A.P. [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)] [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); [Physics Department, University of California at Davis, Davis, California 95616 (United States); Van Hove, M.A. [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)] [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Fadley, C.S. [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)] [Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); [Physics Department, University of California at Davis, Davis, California 95616 (United States)
1998-10-01
Circular dichroism has been observed in the photoelectron diffraction of chemically shifted W 4f photoelectrons from the W(110)1{times}1-O surface. The diffraction peaks from first-layer W atoms bonded most directly to oxygen showed an azimuthal rotation similar to those reported in a prior experiment on Si(001). The maximum rotation angles are also in good agreement with those calculated using the formula {Delta}{phi}=m/kRthinspsin{sup 2}{theta} derived previously by Daimon {ital et al.} [Jpn. J. Appl. Phys., Part 2 {bold 32}, L1480 (1993)] and assuming m=4, which is the maximum magnetic quantum number of the photoelectron wave function. {copyright} {ital 1998} {ital The American Physical Society}
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)
2014-04-15
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.
Study of ICRF wave propagation and plasma coupling efficiency in a linear magnetic mirror device
Peng, S.Y.
1991-07-01
Ion Cyclotron Range of Frequency (ICRF) wave propagation in an inhomogeneous axial magnetic field in a cylindrical plasma-vacuum system has historically been inadequately modelled. Previous works either sacrifice the cylindrical geometry in favor of a simpler slab geometry, concentrate on the resonance region, use a single mode to represent the entire field structure, or examine only radial propagation. This thesis performs both analytical and computational studies to model the ICRF wave-plasma coupling and propagation problem. Experimental analysis is also conducted to compare experimental results with theoretical predictions. Both theoretical as well as experimental analysis are undertaken as part of the thesis. The theoretical studies simulate the propagation of ICRF waves in an axially inhomogeneous magnetic field and in cylindrical geometry. Two theoretical analysis are undertaken - an analytical study and a computational study. The analytical study treats the inhomogeneous magnetic field by transforming the (r,z) coordinate into another coordinate system ({rho},{xi}) that allows the solution of the fields with much simpler boundaries. The plasma fields are then Fourier transformed into two coupled convolution-integral equations which are then differenced and solved for both the perpendicular mode number {alpha} as well as the complete EM fields. The computational study involves a multiple eigenmode computational analysis of the fields that exist within the plasma-vacuum system. The inhomogeneous axial field is treated by dividing the geometry into a series of transverse axial slices and using a constant dielectric tensor in each individual slice. The slices are then connected by longitudinal boundary conditions.
Vlasov Fluid stability of a 2-D plasma with a linear magnetic field null
Kim, J.S.
1984-01-01
Vlasov Fluid stability of a 2-dimensional plasma near an O type magnetic null is investigated. Specifically, an elongated Z-pinch is considered, and applied to Field Reversed Configurations at Los Alamos National Laboratory by making a cylindrical approximation of the compact torus. The orbits near an elliptical O type null are found to be very complicated; the orbits are large and some are stochastic. The kinetic corrections to magnetohydrodynamics (MHD) are investigated by evaluating the expectation values of the growth rates of a Vlasov Fluid dispersion functional by using a set of trial functions based on ideal MHD. The dispersion functional involves fluid parts and orbit dependent parts. The latter involves phase integral of two time correlations. The phase integral is replaced by the time integral both for the regular and for the stochastic orbits. Two trial functions are used; one has a large displacement near the null and the other away from the null.
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)
2014-03-15
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.
2009-01-01
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.
Hitchcock, Adam P.
with results from Nephila clavipes dragline spider silk measured using the in situ rotation device. © 2007
Linear Dichroism in Resonant Inelastic X-Ray Scattering to Molecular
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Summary report for nanoscale magnetics
Tobin, J.G.; Waddill, G.D.; Jankowski, A.F.; Tamura, E.; Sterne, P.A.; Pappas, D.P.; Tong, S.Y.
1993-09-23
We have probed the electronic, geometric, and magnetic nanoscale structure of ultrathin magnetic films, both monolayers and multilayers (Fe/Cu(001), FePt, FeCoPt, UFe{sub 2}, U-S). Techniques used included the MCD (magnetic circular dichroism)-variants of of x-ray absorption, core-level photoemission, and photoelectron diffraction. Progress has been made on nanoscale structure-property relations, in part of coupling of world-class experimentation and theoretical modeling. Feasibility of investigations of 5f magnetism using bulk uranium samples also has been demonstrated.
Cannon, Bradford E.; Smith, Charles W.; Isenberg, Philip A.; Vasquez, Bernard J.; Murphy, Neil; Nuno, Raquel G. E-mail: Charles.Smith@unh.edu E-mail: Bernie.Vasquez@unh.edu E-mail: raquel.nuno@asu.edu
2014-04-01
We have examined Ulysses magnetic field data using dynamic spectrogram techniques that compute wave amplitude, polarization, and direction of propagation over a broad range of frequencies and time. Events were identified that showed a strong polarization signature and an enhancement of power above the local proton gyrofrequency. We perform a statistical study of 502 wave events in an effort to determine when, where, and why they are observed. Most notably, we find that waves arising from newborn interstellar pickup ions are relatively rare and difficult to find. The quantities normally employed in theories of wave growth are neutral atom density and quantities related to their ionization and the subsequent dynamics such as wind speed, solar wind flux, and magnetic field orientation. We find the observations of waves to be largely uncorrelated to these quantities except for mean field direction where quasi-radial magnetic fields are favored and solar wind proton flux where wave observations appear to be favored by low flux conditions which runs contrary to theoretical expectations of wave generation. It would appear that an explanation based on source physics and instability growth rates alone is not adequate to account for the times when these waves are seen.
Resonant and non-resonant magnetic scattering
McWhan, D.B.; Hastings, J.B.; Kao, C.C.; Siddons, D.P.
1991-12-31
The tunability and the polarization of synchrotron radiation open upon new possibilities for the study of magnetism. Studies on magnetic materials performed at the National Synchrotron Light Source are reviewed, and thy fall into four areas: structure, evolution of magnetic order, separation of L and S, and resonance effects. In the vicinity of atomic absorption edges, the Faraday effect, magnetic circular dichroism, and resonant magnetic scattering are all related resonance effects which measure the spin polarized density of states. The production and analysis of polarized beams are discussed in the context of the study of magnetism with synchrotron radiation.
Resonant and non-resonant magnetic scattering
McWhan, D.B.; Hastings, J.B.; Kao, C.C.; Siddons, D.P.
1991-01-01
The tunability and the polarization of synchrotron radiation open upon new possibilities for the study of magnetism. Studies on magnetic materials performed at the National Synchrotron Light Source are reviewed, and thy fall into four areas: structure, evolution of magnetic order, separation of L and S, and resonance effects. In the vicinity of atomic absorption edges, the Faraday effect, magnetic circular dichroism, and resonant magnetic scattering are all related resonance effects which measure the spin polarized density of states. The production and analysis of polarized beams are discussed in the context of the study of magnetism with synchrotron radiation.
Constantin, Dragos E.; Fahrig, Rebecca; Keall, Paul J.
2011-07-15
Purpose: Using magnetic resonance imaging (MRI) for real-time guidance during radiotherapy is an active area of research and development. One aspect of the problem is the influence of the MRI scanner, modeled here as an external magnetic field, on the medical linear accelerator (linac) components. The present work characterizes the behavior of two medical linac electron guns with external magnetic fields for in-line and perpendicular orientations of the linac with respect to the MRI scanner. Methods: Two electron guns, Litton L-2087 and Varian VTC6364, are considered as representative models for this study. Emphasis was placed on the in-line design approach in which case the MRI scanner and the linac axes of symmetry coincide and assumes no magnetic shielding of the linac. For the in-line case, the magnetic field from a 0.5 T open MRI (GE Signa SP) magnet with a 60 cm gap between its poles was computed and used in full three dimensional (3D) space charge simulations, whereas for the perpendicular case the magnetic field was constant. Results: For the in-line configuration, it is shown that the electron beam is not deflected from the axis of symmetry of the gun and the primary beam current does not vanish even at very high values of the magnetic field, e.g., 0.16 T. As the field strength increases, the primary beam current has an initial plateau of constant value after which its value decreases to a minimum corresponding to a field strength of approximately 0.06 T. After the minimum is reached, the current starts to increase slowly. For the case when the beam current computation is performed at the beam waist position the initial plateau ends at 0.016 T for Litton L-2087 and at 0.012 T for Varian VTC6364. The minimum value of the primary beam current is 27.5% of the initial value for Litton L-2087 and 22.9% of the initial value for Varian VTC6364. The minimum current is reached at 0.06 and 0.062 T for Litton L-2087 and Varian VTC6364, respectively. At 0.16 T the beam current increases to 40.2 and 31.4% from the original value of the current for Litton L-2087 and Varian VTC6364, respectively. In contrast, for the case when the electron gun is perpendicular to the magnetic field, the electron beam is deflected from the axis of symmetry even at small values of the magnetic field. As the strength of the magnetic field increases, so does the beam deflection, leading to a sharp decrease of the primary beam current which vanishes at about 0.007 T for Litton L-2087 and at 0.006 T for Varian VTC6364, respectively. At zero external field, the beam rms emittance computed at beam waist is 1.54 and 1.29{pi}-mm-mrad for Litton L-2087 and Varian VTC6364, respectively. For the in-line configuration, there are two particular values of the external field where the beam rms emittance reaches a minimum. Litton L-2087 rms emittance reaches a minimum of 0.72{pi} and 2.01{pi}-mm-mrad at 0.026 and 0.132 T, respectively. Varian VTC6364 rms emittance reaches a minimum of 0.34{pi} and 0.35{pi}-mm-mrad at 0.028 and 0.14 T, respectively. Beam radius dependence on the external field is shown for the in-line configuration for both electron guns. Conclusions: 3D space charge simulation of two electron guns, Litton L-2087 and Varian VTC6364, were performed for in-line and perpendicular external magnetic fields. A consistent behavior of Pierce guns in external magnetic fields was proven. For the in-line configuration, the primary beam current does not vanish but a large reduction of beam current (up to 77.1%) is observed at higher field strengths; the beam directionality remains unchanged. It was shown that for a perpendicular configuration the current vanishes due to beam bending under the action of the Lorentz force. For in-line configuration it was determined that the rms beam emittance reaches two minima for relatively high values of the external magnetic field.
B Wallace; R Janes
2011-12-31
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.
Authors A. L. Barabanov; R. Golub; S. K. Lamoreaux
2006-07-17
The search for particle electric dipole moments (edm) represents a most promising way to search for physics beyond the standard model. A number of groups are planning a new generation of experiments using stored gases of various kinds. In order to achieve the target sensitivities it will be necessary to deal with the systematic error resulting from the interaction of the well-known $\\overrightarrow{v}\\times \\overrightarrow{E}$ field with magnetic field gradients (often referred to as the geometric phase effect (Commins, ED; Am. J. Phys. \\QTR{bf}{59}, 1077 (1991), Pendlebury, JM \\QTR{em}{et al;} Phys. Rev. \\QTR{bf}{A70}, 032102 (2004)). This interaction produces a frequency shift linear in the electric field, mimicking an edm. In this work we introduce an analytic form for the velocity auto-correlation function which determines the velocity-position correlation function which in turn determines the behavior of the frequency shift (Lamoreaux, SK and Golub, R; Phys. Rev \\QTR{bf}{A71}, 032104 (2005)) and show how it depends on the operating conditions of the experiment. We also discuss some additional issues.
Remote Sensing of Chromospheric Magnetic Fields via the Hanle and Zeeman Effects
J. Trujillo Bueno; R. Manso Sainz
2007-11-16
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.
Jr, Peter Chien; Rosenman, Karla; Cheung, Wang; Wang, Nadia; Sanchez, Miguel
2009-01-01
type 1/type 2 mosaic of psoriasis? Dermatology 2006; 212:Magalhaes RF, et al. Linear psoriasis in Brazilian childrensuffering from linear psoriasis along lines of Blaschko. Br
Wallace,B.
2005-01-01
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.
PUBLISHED ONLINE: 8 DECEMBER 2014 | DOI: 10.1038/NPHYS3152 Strong magneto-chiral dichroism in a
Loss, Daniel
contributions and have been rationalized here using the multipolar expansion of matterradiation interaction. I-chiral dichroism is one of the least investigated aspects of lightmatter interaction most likely because known as skyrmions35 to magneto- chiral conductance6 . The interaction between light and matter
Linear Dependence and Linear Independence
PRETEX (Halifax NS) #1 1054 1999 Mar 05 10:59:16
2010-02-12
Feb 16, 2007 ... Observe that the vector (1, 2) is already a linear combination of (1, 0) and (0, 1), and therefore it does not add any new vectors to the linear span ...
Kumar, Punith V. Manju, M. R. Dayal, Vijaylakshmi
2014-04-24
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.
Kliman, G.B.; Brynsvold, G.V.; Jahns, T.M.
1989-08-22
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.
A. L. Barabanov; R. Golub; S. K. Lamoreaux
2005-12-20
The search for particle electric dipole moments represents a most promising way to search for physics beyond the standard model. A number of groups are planning a new generation of experiments using stored gases of various kinds. In order to achieve the target sensitivities it will be necessary to deal with the systematic error resulting from the interaction of the well-known E x v field with magnetic field gradients (often referred to as the geometric phase effect [9,10]). This interaction produces a frequency shift linear in the electric field, mimicking an edm. In this work we introduce an analytic model for the correlation function which determines the behavior of the frequency shift [11], and show in detail how it depends on the operating conditions of the experiment. We also propose a method to directly measure ths correlation function under the exact conditions of a given experiment.
Linear Value Function Approximation Linear Models
Parr, Ronald
Linear Value Function Approximation and Linear Models Ronald Parr Duke University Joint work terminology Â· Various forms of linear value function approximation Â· Linear approximate model formulation #12;Outline Â· Introduce terminology Â· Various forms of linear value function approximation Â· Linear
Enhanced Magnetism of Fe3O4 Nanoparticles with Ga Doping
Pool, V. L.; Klem, M. T.; Chorney, C. L.; Arenholz, E.; Idzerda, Y.U.
2010-10-22
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.
Evidence of half-metallic interface magnetism via local moment formation in Co based Heusler alloys
Telling, N. D.; Keatley, P.S.; van der Laan, G.; Hicken, R.J.; Arenholz, E.; Sakuraba, Y.; Oogane, M.; Ando, Y.; Miyazaki, T.
2008-08-18
In this work we use a combination of x-ray magnetic circular and linear dichroism (XMCD and XMLD) techniques to examine the formation of local moments in Heusler alloys of the composition Co{sub 2}MnX (where X=Si or Al). The existence of local moments in a half-metallic system is reliant upon the band gap in the minority-spin states. By utilizing the element-specific nature of x-ray techniques we are able to explore the origin of the minority-spin band gap in the partial density of states (PDOS), via the degree of localization of moments on Co and Mn atoms. We observe a crucial difference in the localization of the Co moment when comparing Co{sub 2}MnSi (CMS) and Co{sub 2}MnAl (CMA) films that is consistent with the predicted larger minority-spin gap in the Co PDOS for CMS. These results provide important evidence for the dominant role of the Co minority-spin states in realizing half-metallic ferromagnetism (HMF) in these Heusler alloys. They also demonstrate a direct method for measuring the degree of interfacial HMF in the raw materials without the need for fabricating spin-transport devices.
Voltage regulation in linear induction accelerators
Parsons, W.M.
1992-12-29
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.
Voltage regulation in linear induction accelerators
Parsons, William M. (Santa Fe, NM)
1992-01-01
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.
Thomas Wiegelmann; Bernd Inhester
2006-12-21
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.
Chickos, J.S.; Annamalai, A.; Keiderling, T.A.
1986-07-23
The relative rates of geometric isomerization to racemization have been studied for the title compound by using a combination of infrared (IR) and vibrational circular dichroism (VCD) spectroscopies, respectively. The results are interpreted with a kinetic and mechanistic scheme which parallels that used by Berson, Pedersen, and Carpenter on a similar study of chiral cyclopropane-d/sub 2/ thermolysis. Relative rates of isomerization to stereomutation of 1.5 +/- 0.4 were obtained which can be interpreted to be consistent with a mechanism best described by random methylene rotation in tetramethylene-d/sub 2/. This is the first application of VCD to kinetic analysis, and the advantages of IR techniques over the more usually employed UV spectroscopies to this type of basic mechanistic problem are illustrated.
Electronic Non-Contacting Linear Position Measuring System
Post, Richard F. (Walnut Creek, CA)
2005-06-14
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.
The Microscopic Linear Dynamics
Penny, Will
The Microscopic Brain Will Penny Linear Dynamics Exponentials Matrix Exponential Eigendecomposition References The Microscopic Brain Will Penny 7th April 2011 #12;The Microscopic Brain Will Penny Linear;The Microscopic Brain Will Penny Linear Dynamics Exponentials Matrix Exponential Eigendecomposition
Zangrando, M.; Zacchigna, M.; Bondino, F.; Finazzi, M.; Pardini, T.; Plate, M.; Rochow, R.; Cocco, D.; Parmigiani, F.
2004-05-12
BACH, the new soft x-ray beamline for polarization dependent experiments at the Italian synchrotron radiation facility ELETTRA, has been commissioned, characterized and opened to external users. Based on two APPLE II undulators, it covers an energy range between 35 eV and 1600 eV with the control of the light polarization. The monochromator works either in high resolution or high flux mode. Resolving powers of 16000 at 50 eV, 12000 at 90 eV, more than 12000 at 400 eV, 15000 at 534 eV and 6600 at 867 eV have been achieved with the three high resolution gratings. The resolving powers of the high flux grating, which covers the 290 - 1600 eV range, have been measured reaching 7000 at 400 eV and 2200 at 867 eV. The fluxes, in the high resolution mode, range between 4{center_dot}1011 photons/s at 125 eV and 2{center_dot}1010 photons/s at about 1100 eV. Using the high flux grating with the best resolution achievable 1.7{center_dot}1011 photons/s impinge on the sample at 900 eV. Two branches are installed after the monochromator allowing the set-up of two different experimental stations. One of them, besides several facilities for surface preparation and analysis, hosts a compact inelastic soft x-ray spectrometer (ComIXS) dedicated to x-ray emission experiments exploiting the small spot (10 {mu}m in the vertical direction) on the sample. The other branch hosts a liquid helium cryostat equipped with a superconducting coil to perform absorption and transmission experiments with temperatures down to 2 K and magnetic field up to {+-}7 T.
Math 351: Linear Algebra. Text: Elementary Linear Algebra (by me). Instructor: Richard Penney. Office: 822 Mathematics Building Phone: 49--41968. E-mail: ...
Singh, Surendra; Freeland, J. W.; Fitzsimmons, M. R.; Jeen, H.; Biswas, A.
2014-12-14
Here, we present x-ray resonant magnetic dichroism and x-ray resonant magnetic scattering measurements of the temperature dependence of magnetism in Pr-doped La-Ca-Mn-O films grown on (110) NdGaO{sub 3} substrates. We observed thermal hysteresis of the ferromagnetism in one film that also showed large thermal hysteresis of ?18?K in transport measurements. While in a second film of a different nominal chemistry, which showed very small thermal hysteresis ?3?K in transport measurements, no thermal hysteresis of the ferromagnetism was observed. These macroscopic properties are correlated with evolution of surface magnetization across metal insulator transition for these films as observed by soft x-ray resonant magnetic scattering measurements.
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
Linear Models Joint Likelihood
Penny, Will
Hierarchy Will Penny Linear Models Joint Likelihood First Layer Activity Predictive Coding Update Update Connectivity References Hierarchy Will Penny 24th March 2011 #12;Hierarchy Will Penny Linear x1 = W2x2 + e2 #12;Hierarchy Will Penny Linear Models Joint Likelihood First Layer Activity
Villalba-Chávez, S. Müller, C.
2013-12-15
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.
Demmel, James; Holtz, Olga; Dumitriu, Ioana
2007-01-01
than other basic linear algebra subroutines. AcknowledgmentsApplied Numerical Linear Algebra. SIAM, 1997. [23] J.algorithms in numerical linear algebra. SIAM Review, 20:740–
Seymour, P.
1986-01-01
This book deals with the cosmic magnetism in a non-mathematical way. It uses Faraday's very powerful and highly pictorial concept of lines of magnetic force and their associated physical properties to explain the structure and behavior of magnetic fields in extraterrestrial objects. Contents include: forces of nature; magnetic field of earth; solar and interplanetary magnetic fields; magnetic fields in the solar system; stars and pulsars; and magnetic fields of the milky way and other galaxies.
Linear phase compressive filter
McEwan, T.E.
1995-06-06
A phase linear filter for soliton suppression is in the form of a laddered series of stages of non-commensurate low pass filters with each low pass filter having a series coupled inductance (L) and a reverse biased, voltage dependent varactor diode, to ground which acts as a variable capacitance (C). L and C values are set to levels which correspond to a linear or conventional phase linear filter. Inductance is mapped directly from that of an equivalent nonlinear transmission line and capacitance is mapped from the linear case using a large signal equivalent of a nonlinear transmission line. 2 figs.
Fault tolerant linear actuator
Tesar, Delbert
2004-09-14
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.
T. T. Moh
2015-01-20
Linear algebra is second only to calcu lus/differential equations in terms of mathematics of importance to engineering applications. The goal of this course is to ...
New Magnetic confirguration in paramagnetic phase of HoCo2
Bonilla, C.M.; Calvo, I.; Herrero-Albillos, J.; Figueroa, A.I.; Castan-Guerrero, C.; Bertolome, J.; Rodriguez-Velamazan, J.A.; Schmitz, D.; Weschke, E.; Paudyal, Durga; Pecharsky, Vitalij; Gschneidner Jr, Karl; Bartolome, F.; Garcia, D.
2012-02-23
X-ray magnetic circular dichroism (XMCD) measurements on HoCo2 reveal the inversion of Co moment at temperatures higher than the critical temperature, Tc, showing that the net magnetization under a field of the Ho and Co sublattices remain antiparallel even above Tc. The Ho moment also changes its orientation to align antiparallel to the applied field at high temperature giving rise to a new magnetic configuration in the paramagnetic regime. Transverse susceptibility (TS) and small angle neutron scattering (SANS) measurements performed above Tc indicate the existence of sizable magnetic short-range correlated regions in HoCo2. First principles calculations based on spin polarized local-density approximation, LSDA+U havebeen performed to obtain insights on the origin of the short-range correlated volume.
Engineering Gilbert damping by dilute Gd doping in soft magnetic Fe thin films
Zhang, W. Jiang, S.; Sun, L.; Wang, Y. K.; Zhai, Y.; Wong, P. K. J.; Wang, K.; Jong, M. P. de; Wiel, W. G. van der; Laan, G. van der
2014-05-07
By analyzing the ferromagnetic resonance linewidth, we show that the Gilbert damping constant in soft magnetic Fe thin films can be enhanced by ?6 times with Gd doping of up to 20%. At the same time, the magnetic easy axis remains in the film plane while the coercivity is strongly reduced after Gd inclusion. X-ray magnetic circular dichroism measurements reveal a strong increase in the orbital-to-spin moment ratio of Fe with increasing Gd concentration, in full agreement with the increase in the Gilbert damping obtained for these thin films. Combined with x-ray diffraction and vibrating sample magnetometry, the results demonstrate that the FeGd thin films with dilute Gd doping of up to 20% are promising candidates for spin-transfer-torque applications in soft magnetic devices, in which an enhanced damping is required.
Design and construction of a precision tubular linear motor and controller
Murphy, Bryan Craig
2004-09-30
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...
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
Coronal heating in multiple magnetic threads
Tam, K V; Browning, P K; Cargill, P J
2015-01-01
Context. Heating the solar corona to several million degrees requires the conversion of magnetic energy into thermal energy. In this paper, we investigate whether an unstable magnetic thread within a coronal loop can destabilise a neighbouring magnetic thread. Aims. By running a series of simulations, we aim to understand under what conditions the destabilisation of a single magnetic thread can also trigger a release of energy in a nearby thread. Methods. The 3D magnetohydrodynamics code, Lare3d, is used to simulate the temporal evolution of coronal magnetic fields during a kink instability and the subsequent relaxation process. We assume that a coronal magnetic loop consists of non-potential magnetic threads that are initially in an equilibrium state. Results. The non-linear kink instability in one magnetic thread forms a helical current sheet and initiates magnetic reconnection. The current sheet fragments, and magnetic energy is released throughout that thread. We find that, under certain conditions, this ...
W. B. Vasantha Kandasamy; Florentin Smarandache
2008-07-18
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.
Penny, Will
Empirical Bayes Will Penny Linear Models fMRI analysis Gradient Ascent Online learning Delta Rule Maximum Likelihood Augmented Form ReML Objective Function References Empirical Bayes Will Penny 3rd March 2011 #12;Empirical Bayes Will Penny Linear Models fMRI analysis Gradient Ascent Online learning Delta
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. ...
Linearly parameterized bandits
Tsitsiklis, John N.
We consider bandit problems involving a large (possibly infinite) collection of arms, in which the expected reward of each arm is a linear function of an r-dimensional random vector Z ? ?(superscript r), where r ? 2. The ...
The International Linear Collider
Jim Brau; Paul Grannis; Mike Harrison; Michael Peskin; Marc Ross; Harry Weerts
2013-04-09
We present a brief summary of the International Linear Collider as documented in the 2013 Technical Design Report. The Technical Design Report has detailed descriptions of the accelerator baseline design for a 500 GeV e+e- linear collider, the R&D program that has demonstrated its feasibility, the physics goals and expected sensitivities, and the description of the ILD and SiD detectors and their capabilities.
Magnets & Magnet Condensed Matter Science
McQuade, D. Tyler
Sights from around the Magnet Lab in 2010. On the cover MAGNETS & MAGNET MATERIALS Engineering materials in Mesoporous Silica SBA-15 31 YBCO Pancake Wound Test Coil for 32-T Magnet Development 32 Strong Vortex Pinning from Marine Cyanobacteria 37 Heavy Petroleum Composition 2. Progression of the Boduszynski Model
Math 511 Linear Algebra with Applications. Text: Linear Algebra and ...
Jaroslaw Wlodarczyk
2007-12-15
Math 511 Linear Algebra with Applications. This is a Linear Algebra course primarily for graduate engineering students. Enclosed is a sample outline which is ...
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
Depth-dependent magnetism in epitaxial MnSb thin films: effects of surface passivation and cleaning
Aldous J. D.; Sanchez-Hanke C.; Burrows, C.W.; Maskery, I.; Brewer, M.S.; Hase, T.P.A.; Duffy, J.A.; Lees, M. Rs; Decoster, T.; Theis, W.; Quesada, A.; Schmid, A.K.; Bell, G.R.
2012-03-15
Depth-dependent magnetism in MnSb(0001) epitaxial films has been studied by combining experimental methods with different surface specificities: polarized neutron reflectivity, x-ray magnetic circular dichroism (XMCD), x-ray resonant magnetic scattering and spin-polarized low energy electron microscopy (SPLEEM). A native oxide {approx}4.5 nm thick covers air-exposed samples which increases the film's coercivity. HCl etching efficiently removes this oxide and in situ surface treatment of etched samples enables surface magnetic contrast to be observed in SPLEEM. A thin Sb capping layer prevents oxidation and preserves ferromagnetism throughout the MnSb film. The interpretation of Mn L{sub 3,2} edge XMCD data is discussed.
Linear Algebra: Ideas and Applications
Linear Algebra: Ideas and Applications. [photo]. Welcome to the web page for Linear Algebra: Idaes and Applications by Richard Penney. This web site is ...
Wave propagation in the magnetic sun
T. Hartlep; M. S. Miesch; N. N. Mansour
2008-05-03
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.
Linear Discriminant Functions Linear Discriminant Functions and Decisions Surfaces
Linear Discriminant Functions Â· Linear Discriminant Functions and Decisions Surfaces Â· Generalized Linear Discriminant Functions #12;Srihari: CSE 555 Introduction Â· Parametric Methods Â· Underlying pdfs are known Â· Training samples used to estimate pdf parameters Â· Linear Discriminant Functions Â· Forms
QPL 2005 Preliminary Version De-linearizing linearity: projective quantum
Selinger, Peter
QPL 2005 Preliminary Version De-linearizing linearity: projective quantum axiomatics from strong the linear structure of Hilbert spaces into several constituents which play different roles in quantum)famous Birkhoff- von Neumann paper [7]. The bulk of the linear structure required to reason about quantum
Linear Fixed-Field Multi-Pass Arcs for Recirculating Linear Accelerators
V.S. Morozov, S.A. Bogacz, Y.R. Roblin, K.B. Beard
2012-06-01
Recirculating Linear Accelerators (RLA's) provide a compact and efficient way of accelerating particle beams to medium and high energies by reusing the same linac for multiple passes. In the conventional scheme, after each pass, the different energy beams coming out of the linac are separated and directed into appropriate arcs for recirculation, with each pass requiring a separate fixed-energy arc. In this paper we present a concept of an RLA return arc based on linear combined-function magnets, in which two and potentially more consecutive passes with very different energies are transported through the same string of magnets. By adjusting the dipole and quadrupole components of the constituting linear combined-function magnets, the arc is designed to be achromatic and to have zero initial and final reference orbit offsets for all transported beam energies. We demonstrate the concept by developing a design for a droplet-shaped return arc for a dog-bone RLA capable of transporting two beam passes with momenta different by a factor of two. We present the results of tracking simulations of the two passes and lay out the path to end-to-end design and simulation of a complete dog-bone RLA.
Compensation of instabilities in magnetic Taylor-Couette flow Dima Shalybkov*
for the problem of a plasma confinement by the magnetic field. DOI: 10.1103/PhysRevE.76.027302 PACS number s : 47 The axisymmetric linear stability of the Taylor-Couette flow with an azimuthal magnetic field is considered magnetic field can be linearly stable. The flow stabilization takes place for both ideal and dissipative
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
2010-12-08
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.
Not Available
1994-08-01
This report discusses the following topics on superconducting magnets: D19B and -C: The next steps for a record-setting magnet; D20: The push beyond 10 T: Beyond D20: Speculations on the 16-T regime; other advanced magnets for accelerators; spinoff applications; APC materials development; cable and cabling-machine development; and high-{Tc} superconductor at low temperature.
Becker, Jörg D
2015-01-01
In many European countries the growth of the real GDP per capita has been linear since 1950. An explanation for this linearity is still missing. We propose that in artificial intelligence we may find models for a linear growth of performance. We also discuss possible consequences of the fact that in systems with linear growth the percentage growth goes to zero.
Automatic Linear Orders (Revised Version)
Stephan, Frank
CDMTCS Research Report Series Automatic Linear Orders and Trees (Revised Version) Bakhadyr; Automatic Linear Orders and Trees Bakhadyr Khoussainov, Sasha Rubin and Frank Stephan November 13, 2003 emphasis is on trees and linear orders. We study the relationship between automatic linear orders and trees
Development of compact linear accelerator in KBSI
Yoon, Jang-Hee; Lee, Byoung-Seob; Choi, Seyong; Park, Jin Yong; Ok, Jung-Woo; Won, Mi-Sook [Busan Center, Korea Basic Science Institute, Busan 609-735 (Korea, Republic of)
2012-02-15
The compact linear accelerator using a 28 GHz ECRIS is under construction in KBSI, South Korea. The main capability of this facility is the production of fast neurons for the neutron radiography. The designing of a superconducting magnet, microwave transmission system, beam extraction, and plasma chamber of ECRIS were finished. The nominal axial design fields of the magnets are 3.6 T at injection and 2.2 T at extraction; the nominal radial design field strength at the plasma chamber wall is 2.1 T. We already installed 10 kW, 28 GHz gyrotron, and tested a microwave power from gyrotron using a dummy load. The current status will be discussed in this paper.
Laser Transmission Studies with Magnetic Nanofluids
Chintamani Pai; H. Muthurajan; Nooris Momin; Radha Srinivasan; R. Nagarajan
2015-09-14
Transmission of He-Ne (632 nm, 10 mW) Gaussian laser beam through Hexane and Water based magnetic nanofluids containing Fe3O4 nanoparticles show strong non-linear and magneto-optical effects. Application of external magnetic field (up to 1.7 Wb/m2) perpendicular to the incident laser beam produces a change in forward scattered pattern of the incident laser beam. Dependence of forward scattered patterns in presence of external magnetic field has been studied. Image processing has been carried out to understand spatial distribution of the forward scattered patterns and temporal evolution of patterns involving particle image velocimetry technique. Change in non-linear refractive index is estimated for samples showing self-diffraction arising from higher order non-linear optical effect. Observed effects are useful for understanding light scattering from magnetic nanofluids and developing optofluidic devices and sensors.
Laser Transmission Studies with Magnetic Nanofluids
Pai, Chintamani; Momin, Nooris; Srinivasan, Radha; Nagarajan, R
2015-01-01
Transmission of He-Ne (632 nm, 10 mW) Gaussian laser beam through Hexane and Water based magnetic nanofluids containing Fe3O4 nanoparticles show strong non-linear and magneto-optical effects. Application of external magnetic field (up to 1.7 Wb/m2) perpendicular to the incident laser beam produces a change in forward scattered pattern of the incident laser beam. Dependence of forward scattered patterns in presence of external magnetic field has been studied. Image processing has been carried out to understand spatial distribution of the forward scattered patterns and temporal evolution of patterns involving particle image velocimetry technique. Change in non-linear refractive index is estimated for samples showing self-diffraction arising from higher order non-linear optical effect. Observed effects are useful for understanding light scattering from magnetic nanofluids and developing optofluidic devices and sensors.
Banks, R.M.
1986-01-14
This patent describes a linear output nitinol engine consisting of a number of integrated communicating parts. The engine has an external support framework which is described in detail. The patent further describes a wire transport mechanism, a pair of linkage levers with a loom secured to them, a number of nitinol wires strung between the looms, and a power takeoff block secured to the linkage levers. A pulley positioned in a flip-flop supporting bracket and a power takeoff modality including a tension member connected to a power output cable in order to provide linear power output transmission is described. A method for biasing the timing and the mechanism for timing the synchronization of the throw over arms and the flip-flop of the pulley are also described.
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
2014-12-23
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.
Combustion powered linear actuator
Fischer, Gary J. (Albuquerque, NM)
2007-09-04
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.
Buttram, M.T.; Ginn, J.W.
1988-06-21
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.
The International Linear Collider
Barish, Barry
2013-01-01
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...
Crozier, Richard Carson
2014-06-30
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 ...
Algorithms for Solving Linear Congruences and Systems of Linear Congruences
Florentin Smarandache
2007-02-16
In this article we determine several theorems and methods for solving linear congruences and systems of linear congruences, and we find the number of distinct solutions. Many examples of solving congruences are given.
Aleks Kleyn
2010-01-27
On the set of mappings of the given set, we define the product of mappings. If A is associative algebra, then we consider the set of matrices, whose elements are linear mappings of algebra A. In algebra of matrices of linear mappings we define the operation of product. The operation is based on the product of mappings. If the matrix a of linear mappings has an inverse matrix, then the quasideterminant of the matrix a and the inverse matrix are matrices of linear mappings. In the paper, I consider conditions when a matrix of linear mappings has inverse matrix, as well methods of solving a system of linear equations in an associative algebra.
Modified Magnetic Ground State in Nimn (2) O (4) Thin Films
Nelson-Cheeseman, B.B.; Chopdekar, R.V.; Iwata, J.M.; Toney, M.F.; Arenholz, E.; Suzuki, Y.; /SLAC
2012-08-23
The authors demonstrate the stabilization of a magnetic ground state in epitaxial NiMn{sub 2}O{sub 4} (NMO) thin films not observed in their bulk counterpart. Bulk NMO exhibits a magnetic transition from a paramagnetic phase to a collinear ferrimagnetic moment configuration below 110 K and to a canted moment configuration below 70 K. By contrast, as-grown NMO films exhibit a single magnetic transition at 60 K and annealed films exhibit the magnetic behavior found in bulk. Cation inversion and epitaxial strain are ruled out as possible causes for the new magnetic ground state in the as-grown films. However, a decrease in the octahedral Mn{sup 4+}:Mn{sup 3+} concentration is observed and likely disrupts the double exchange that produces the magnetic state at intermediate temperatures. X-ray magnetic circular dichroism and bulk magnetometry indicate a canted ferrimagnetic state in all samples at low T. Together these results suggest that the collinear ferrimagnetic state observed in bulk NMO at intermediate temperatures is suppressed in the as grown NMO thin films due to a decrease in octahedral Mn{sup 4+}, while the canted moment ferrimagnetic ordering is preserved below 60 K.
Modified magnetic ground state in NiMn2O4 thin films
Nelson-Cheeseman, B. B.; Chopdekar, R. V.; Toney, M. F.; Arenholz, E.; Suzuki, Y.; Iwata, J.M.
2010-08-03
We demonstrate the stabilization of a magnetic ground state in epitaxial NiMn2O4 (NMO) thin films not observed in their bulk counterpart. Bulk NMO exhibits a magnetic transition from a paramagnetic phase to a collinear ferrimagnetic moment configuration below 110 K and to a canted moment configuration below 70 K. By contrast, as-grown NMO films exhibit a single magnetic transition at 60 K and annealed films exhibit the magnetic behavior found in bulk. Cation inversion and epitaxial strain are ruled out as possible causes for the new magnetic ground state in the as-grown films. However, a decrease in the octahedral Mn{sup 4+}:Mn{sup 3+} concentration is observed and likely disrupts the double exchange that produces the magnetic state at intermediate temperatures. X-ray magnetic circular dichroism and bulk magnetometry indicate a canted ferrimagnetic state in all samples at low temperature. Together these results suggest that the collinear ferrimagnetic state observed in bulk NMO at intermediate temperatures is suppressed in the as grown NMO thin films due to a decrease in octahedral Mn{sup 4+} while the canted moment ferrimagnetic ordering is preserved below 60 K.
Mi, Chunting "Chris"
IEEE TRANSACTIONS ON ENERGY CONVERSION, VOL. 27, NO. 2, JUNE 2012 489 Modeling of a Complementary and Modular Linear Flux-Switching Permanent Magnet Motor for Urban Rail Transit Applications Ruiwu Cao-switching permanent magnet (MLFSPM) motor is investi- gated, in which both the magnets and armature windings
Kerns, J.A.; Stone, R.R.; Fabyan, J.
1987-10-06
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 magnetic 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. 3 figs.
Kerns, John A. (Livermore, CA); Stone, Roger R. (Walnut Creek, CA); Fabyan, Joseph (Livermore, CA)
1987-01-01
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 magnetic 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.
The International Linear Collider
Marco Battaglia
2007-05-28
The International Linear Collider (ILC) is the next large scale project in accelerator particle physics. Colliding electrons with positrons at energies from 0.3 TeV up to about 1 TeV, the ILC is expected to provide the accuracy needed to complement the LHC data and extend the sensitivity to new phenomena at the high energy frontier and answer some of the fundamental questions in particle physics and in its relation to Cosmology. This paper reviews some highlights of the ILC physics program and some of the major challenges for the accelerator and detector design.
Park, Joung Won
2010-10-12
, and Temperature (PVT) variations and increase high power input capability. After analyzing and designing a resistive feedback LNA, novel linearization methods were applied. A highly linear broadband LNA is designed and simulated in 65nm CMOS technology. Simulation...
Wave functions of linear systems
Tomasz Sowinski
2007-06-05
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.
UNBOUNDED DISJOINTNESS PRESERVING LINEAR FUNCTIONALS
Wong, Ngai-Ching
UNBOUNDED DISJOINTNESS PRESERVING LINEAR FUNCTIONALS LAWRENCE G. BROWN AND NGAI-CHING WONG Abstract vanishing at infinity. In this paper, we shall study unbounded disjointness preserving linear functionals. In particular, every unbounded disjointness preserving linear functional of c0 can be constructed explicitly
Simple Linear Regression Basic Ideas
Simple Linear Regression Basic Ideas Some Examples Least Squares Statistical View of Least Squares of Least Squares #12;Simple Linear Regression Basic Ideas Some Examples Least Squares Basic Ideas Suppose #12;Simple Linear Regression Basic Ideas Some Examples Least Squares Basic Ideas Suppose we have two
Linear Solvers 1.Introduction [1
McCalley, James D.
linear algebra packages including LAPACK, ScaLAPACK and PETSc, are built on top of BLAS. Most of standard, portable solver libraries available, including: BLAS (Basic linear algebra subprograms): Many (Automatically Tuned Linear Algebra Software package) is a version of BLAS that, upon installation, tests
Special set linear algebra and special set fuzzy linear algebra
W. B. Vasantha Kandasamy; Florentin Smarandache; K. Ilanthenral
2009-12-30
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.
A linear induction motor conveyer
Solinsky, Kenneth Sheldon
1973-01-01
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... which *end to move the conducting bsr Page 28 Obtaining power with a phase relationship of 60o 3l Magnetic field around a cur~ ent carrying wire 32 Magnetic field around two sides of a long rectangular current loop 32 20, Contribution of coils...
Investigation into electron cloud effects in the International Linear Collider positron damping ring
Furman, Miguel
Investigation into electron cloud effects in the International Linear Collider positron damping; published 17 March 2014) 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
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
Kerns, J.A.; Stone, R.R.; Fabyan, J.
1985-02-12
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.
Optimization of a dual acting, magnetically driven, linear actuator
Willerton, Justin Ryan
2002-01-01
program will be used to model the thermal response of the electrical coils so a maximum temperature can be found. These simulations will be part of a Matlab optimization routine. This routine will optimize the actuator's geometry by minimizing a cost...
High force density linear permanent magnet motors : "electromagnetic muscle actuators"
Ruddy, Bryan P. (Bryan Paul), 1983-
2012-01-01
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, ...
Matsui, Hiroshi (Glen Rock, NJ); Matsunaga, Tadashi (Tokyo, JP)
2010-11-16
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.
The International Linear Collider
Karsten Buesser
2013-06-13
The International Linear Collider (ILC) is a proposed electron-positron collider for the centre-of-mass energy range of 200 to 500 GeV and with upgrade options towards 1 TeV. The ILC would be the ideal tool to explore with high precision the properties of the new Higgs-like particle that has recently been discovered at the LHC with a mass of around 125 GeV. The ILC accelerator design is based on the mature superconducting technology that has been developed in the TESLA collaboration and that is currently being used for the European XFEL. The exploitation of the huge physics potential of the ILC is a challenge for the design of the ILC detectors.
Positrons for linear colliders
Ecklund, S.
1987-11-01
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)
Linear Algebraic Method for Non-Linear Map Analysis
Yu,L.; Nash, B.
2009-05-04
We present a newly developed method to analyze some non-linear dynamics problems such as the Henon map using a matrix analysis method from linear algebra. Choosing the Henon map as an example, we analyze the spectral structure, the tune-amplitude dependence, the variation of tune and amplitude during the particle motion, etc., using the method of Jordan decomposition which is widely used in conventional linear algebra.
International linear collider reference design report
Aarons, G.
2008-01-01
A. Loew, et al. , “International Linear Collider Technologyfor the International Linear Collider”, in preparation [37]for the International Linear Collider,” in PAC05,http://
Adjustable permanent quadrupoles for the next linear collider
James T. Volk et al.
2001-06-22
The proposed Next Linear Collider (NLC) will require over 1400 adjustable quadrupoles between the main linacs' accelerator structures. These 12.7 mm bore quadrupoles will have a range of integrated strength from 0.6 to 138 Tesla, with a maximum gradient of 141 Tesla per meter, an adjustment range of +0 to {minus}20% and effective lengths from 324 mm to 972 mm. The magnetic center must remain stable to within 1 micron during the 20% adjustment. In an effort to reduce costs and increase reliability, several designs using hybrid permanent magnets have been developed. Four different prototypes have been built. All magnets have iron poles and use Samarium Cobalt to provide the magnetic fields. Two use rotating permanent magnetic material to vary the gradient, one uses a sliding shunt to vary the gradient and the fourth uses counter rotating magnets. Preliminary data on gradient strength, temperature stability, and magnetic center position stability are presented. These data are compared to an equivalent electromagnetic prototype.
Fryberger, D.
1984-12-01
In this talk on magnetic monopoles, first the author briefly reviews some historical background; then, the author describes what several different types of monopoles might look like; and finally the author discusses the experimental situation. 81 references.
Linear and nonlinear wave propagation in weakly relativistic quantum plasmas
Stefan, Martin; Brodin, Gert [Department of Physics, Umea University, SE-901 87 Umea (Sweden)
2013-01-15
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.
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
Linear Programming and Kantorovich Spaces
S. Kutateladze
2009-05-08
This is a brief overview of the life of Leonid Kantorovich (1912--1986) and his contribution to the fields of linear programming and ordered vector spaces.
Superconducting magnet development in Japan
Yasukochi, K.
1983-05-01
The present state of R and D works on the superconducting magnet and its applications in Japan are presented. On electrical rotating machines, 30 MVA superconducting synchronous rotary condenser (Mitsubishi and Fuji) and 50 MVA generator are under construction. Two ways of ship propulsion by superconducting magnets are developing. A superconducting magnetically levitated and linear motor propelled train ''MAGLEV'' was developed by the Japan National Railways (JNR). The superconducting magnet development for fusion is the most active field in Japan. The Cluster Test program has been demonstrated on a 10 T Nb/sub 3/Sn coil and the first coil of Large Coil Task in IEA collaboration has been constructed and the domestic test was completed in JAERI. These works are for the development of toroidal coils of the next generation tokamak machine. R and D works on superconducting ohmic heating coil are in progress in JAERI and ETL. The latter group has constructed 3.8 MJ pulsed coil. A high ramp rate of changing field in pulsed magnet, 200 T/s, has been tested successfully. High Energy Physics Laboratory (KEK) are conducting active works. The superconducting ..mu.. meson channel and ..pi.. meson channel have been constructed and are operating successfully. KEK has also a project of big accelerator named ''TRISTAN'', which is similar to ISABELLE project of BNL. Superconducting synchrotron magnets are developed for this project. The development of superconducting three thin wall solenoid has been started. One of them, CDF, is progressing under USA-Japan collaboration.
Faraday rotation assisted by linearly polarized light
Choi, Jai Min; Kim, Jang Myun; Cho, D.
2007-11-15
We demonstrate a type of chiral effect of an atomic medium. Polarization rotation of a probe beam is observed only when both a magnetic field and a linearly polarized coupling beam are present. We compare it with other chiral effects like optical activity, the Faraday effect, and the optically induced Faraday effect from the viewpoint of spatial inversion and time reversal transformations. As a theoretical model we consider a five-level configuration involving the cesium D2 transition. We use spin-polarized cold cesium atoms trapped in a magneto-optical trap to measure the polarization rotation versus probe detuning. The result shows reasonable agreement with a calculation from the master equation of the five-level configuration.
Another Detector for the International Linear Collider
Nural Akchurin; Sehwook Lee; Richard Wigmans; Hanna Arnold; Aaron Bazal; Robert Basili; John Hauptman; Tim Overton; Andrew Priest; Bingzhe Zhao; Alexander Mikhailichenko; Michele Cascella; Franco Grancagnolo; Giovanni Tassielli; Franco Bedeschi; Fabrizio Scuri; Sung Keun Park; Fedor Ignatov; Gabriella Gaudio; Michele Livan
2013-07-25
We describe another detectora designed for the International Linear Collider based on several tested instrumentation innovations in order to achieve the necessary experi- mental goal of a detecter that is 2-to-10 times better than the already excellent SLC and LEP detectors, in particular, (1) dual-readout calorimeter system based on the RD52/DREAM measurements at CERN, (2) a cluster-counting drift chamber based on the successful kloe chamber at Frascati, and (3) a second solenoid to return the magnetic flux without iron. A high-performance pixel vertex chamber is presently undefined. We discuss particle identification, momentum and energy resolutions, and the machine-detector interface that together offer the possibility of a very high-performance detector for $e^+e^-$physics up to $\\sqrt{s} = 1$ TeV.
Linear diffusion into a Faraday cage.
Warne, Larry Kevin; Lin, Yau Tang; Merewether, Kimball O.; Chen, Kenneth C.
2011-11-01
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.
Royet, J.M.
2011-01-01
J. Royet, "Magnet Cable Manufacturing", oral presentation atDivision Magnet Cable Manufacturing J. Royet October 1990J I Magnet Cable Manufacturing* John Royet Accelerator &
Optically induced magnetization in homogeneous, undoped dielectric media
Cafarella, Michael J.
frequencies is one half the electric dipole (ED) moment. As a consequence, magnetic dipole radiation generated dipole (ED). This is because only the electric field can generate linear charge acceleration and, and H2O at the fundamental input frequency. Excellent agreement is obtained with a classical magnetic
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
2007-03-19
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.
Electric-Magnetic Duality Invariant Lagrangians
Machiko Hatsuda; Kiyoshi Kamimura; Sayaka Sekiya
1999-08-24
We find general non-linear lagrangians of a U(1) field invariant under electric-magnetic duality. They are characterized by an arbitrary function and go to the Maxwell theory in the weak field limit. We give some explicit examples which are generalizations of the Born-Infeld theory.
Acoustic emission linear pulse holography
Collins, H.D.; Busse, L.J.; Lemon, D.K.
1983-10-25
This device relates to the concept of and means for performing Acoustic Emission Linear Pulse Holography, which combines the advantages of linear holographic imaging and Acoustic Emission into a single non-destructive inspection system. This unique system produces a chronological, linear holographic image of a flaw by utilizing the acoustic energy emitted during crack growth. The innovation is the concept of utilizing the crack-generated acoustic emission energy to generate a chronological series of images of a growing crack by applying linear, pulse holographic processing to the acoustic emission data. The process is implemented by placing on a structure an array of piezoelectric sensors (typically 16 or 32 of them) near the defect location. A reference sensor is placed between the defect and the array.
Linear Consistency Testing Yonatan Aumann
Sudan, Madhu
of Blum, Luby and Rubinfeld [?] to check the linear-consistency of three functions f1, f2, f3 mapping and check if f1(x) + f2(y) = f3(x + y). We analyze this test for two cases: (1) G and H are arbitrary the consistency of multiple functions. Given a triple of functions f1, f2, f3 : G H, we say that they are "linear
Masaaki Yamada, Russell Kulsrud and Hantao Ji
2009-09-17
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
International Linear Collider Technical Design Report - Volume...
Office of Scientific and Technical Information (OSTI)
Technical Report: International Linear Collider Technical Design Report - Volume 2: Physics Citation Details In-Document Search Title: International Linear Collider Technical...
Math 511 Linear Algebra with Applications
Math 511 Linear Algebra with Applications. Fall 2005. This is a Linear Algebra course primarily for graduate engineering students. Enclosed is a sample outline
Including stereoscopic information in the reconstruction of coronal magnetic fields
T. Wiegelmann; T. Neukirch
2008-01-23
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.
Non-linear Plasma Wake Growth of Electron Holes
Hutchinson, I H; Zhou, C
2015-01-01
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...
Highly linear low noise amplifier
Ganesan, Sivakumar
2007-09-17
VgVgVgi (4) Where gm1 is its transconductance, gm2 represents its second order non-linearity obtained by the second order derivative of FET transfer characteristics (Id-Vgs) and gm3 is its third order non-linearity obtained by the third order... for the above mentioned currents are given below. 3 3213 2 21211 3 3 3 3 2 21 *),,(*),(*)( xxxBAout BbB AaAaAaA VsssCVssCVsCiii Vgi VgVgVgi ++=+= = ++= (14) Where g1a represents the transconductance of the main amplifier and g2a and g3a represent the second...
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
Satti, John A. (Naperville, IL)
1980-01-01
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.
Linear regression issues in astronomy
Babu, G. Jogesh
Linear regression issues in astronomy Eric Feigelson Summer School in astrostatistics References regression Seeking the intrinsic relationship between two properties without specifying `dependent' and `independent' variables OLS(Y|X) OLS(X|Y) (inverse regr) Four symmetrical regression lines #12;Analytical
Linear electric field mass spectrometry
McComas, D.J.; Nordholt, J.E.
1992-12-01
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.
Matrix polynomials and structured linearizations.
Bigelow, Stephen
Matrix polynomials and structured linearizations. Advisor: Maria Isabel Bueno Cachadina Let P() = Akk + Ak-1k-1 + · · · + A0 (1) be a matrix polynomial of degree k 2, where the coefficients Ai are n × n matrices with entries in a field F. A matrix pencil L() = L1 - L0, with L1, L0 Mkn
Saturation and linear transport equation
Krzysztof Kutak
2009-04-29
We show that the GBW saturation model provides an exact solution to the one dimensional linear transport equation. We also show that it is motivated by the BK equation considered in the saturated regime when the diffusion and the splitting term in the diffusive approximation are balanced by the nonlinear term.
The equations Linear plate equation
Grunau, Hans-Christoph
The equations Linear plate equation Paneitz equation Willmore equation, one dimensional Some fourth order differential equations related to differential geometry Hans-Christoph Grunau OttovonGuerickeUniversit¨at Magdeburg Nice, January 26, 2006 Hans-Christoph Grunau Differential equations of fourth order #12;The
Knot undulator to generate linearly polarized photons with low on-axis power density
Qiao, S; Feng, Donglai; Hussain, Z; Shen, Z -X
2008-01-01
Heat load on beamline optics is a serious problem to generate pure linearly polarized photons in the third generation synchrotron radiation facilities. For permanent magnet undulators, this problem can be overcome by a figure-8 operating mode. But there is still no good method to tackle this problem for electromagnetic elliptical undulators. Here, a novel operating mode is suggested, which can generate pure linearly polarized photons with very low on-axis heat load. Also the available minimum photon energy of linearly polarized photons can be extended much by this method.
Why quantum dynamics is linear
Thomas F. Jordan
2007-02-16
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.
Fast exact linear algebra, LinBox
Pernet, Clément
Fast exact linear algebra, LinBox Clément Pernet Introduction LinBox: an overview Principles-place eliminations Fast matrix multiplication Linear algebra over big integers Fast exact linear algebra: LinBox Clément PERNET SAGE Days 6, November 11, 2007 #12;Fast exact linear algebra, LinBox Clément Pernet
Termination of Linear Programs Ashish Tiwari
Tiwari, Ashish
Termination of Linear Programs Ashish Tiwari SRI International, 333 Ravenswood Ave, Menlo Park, CA, U.S.A tiwari@csl.sri.com Abstract. We show that termination of a class of linear loop programs is decidable. Linear loop programs are discrete-time linear systems with a loop condition governing termination
Termination of Linear Programs Ashish Tiwari #
Tiwari, Ashish
Termination of Linear Programs Ashish Tiwari # SRI International, 333 Ravenswood Ave, Menlo Park, CA, U.S.A tiwari@csl.sri.com Abstract. We show that termination of a class of linear loop programs is decidable. Linear loop programs are discreteÂtime linear systems with a loop condition governing termination
Sikes, Derek S.
: This is a first course in linear algebra that starts with the basic objects vectors, matrices, systems of linear equations, and vector spaces and follows with the elements of matrix algebra and solving systems roughly to chapters 1-6 in the textbook. Linear algebra is concerned with the study of systems of linear
The Next Linear Collider Klystron Development Program*
E. Jongewaard; G. Caryotakis; C. Pearson; R. M. Phillips; D. Sprehn; A. Vlieks
2000-08-19
Klystrons capable of 75 MW output power at 11.4 GHz have been under development at SLAC for the last decade. The work has been part of the program to realize all the components necessary for the construction of the Next Linear Collider (NLC). The effort has produced a family of solenoid-focused 50 MW klystrons, which are currently powering a 0.5 GeV test accelerator at SLAC and several test stands, where high power components are evaluated and fundamental research is performed studying rf breakdown and dark current production. Continuing development has resulted in a Periodic Permanent Magnet (PPM) focused 50 MW klystron, tested at SLAC and subsequently contracted for manufacture by industry in England and Japan. A 75 MW version of that PPM klystron was built at SLAC and reached 75 MW, with 2.8 microsecond pulses. Based on this design, a prototype 75 MW klystron, designed for low-cost manufacture, is currently under development at SLAC, and will eventually be procured from industry in modest quantities for advanced NLC tests. Beyond these developments, the design of Multiple Beam Klystrons (MBKs) is under study at SLAC. MBKs offer the possibility of considerably lower modulator costs by producing comparable power to the klystrons now available, at much lower voltages. * This work supported by the Department of Energy under contract DE-AC03-76SF00515
Set Linear Algebra and Set Fuzzy Linear Algebra
W. B. Vasantha Kandasamy; Florentin Smarandache; K. Ilanthenral
2008-06-17
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.
Nanostructured magnetic materials
Chan, Keith T.
2011-01-01
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
Linear Gain for the Microbunching Instability in an RF Compressor
Venturini, M.; Migliorati, M.; Ronsivalle, C.; Vaccarezza, C.
2009-05-01
Velocity (or rf) compression has been suggested as a technique for bunch compression complementary to the more established technique involving magnetic chicanes and represents an important research item being investigated at the SPARC test facility. One of the aspects of this technique still not sufficiently understood is its possible impact on the microbunching instability. The purpose of this report is to present the analytical framework for investigating this instability in rf compressors. We use methods similar to those successfully applied to magnetic compressors and derive some integral equations yielding the gain for the instability in linear approximation. The focus here is on the derivation of the relevant equations. Although examples of solutions to these equations are provided we defer a more comprehensive discussion of their implication to a future report. The present study is part of a larger effort for a more comprehensive investigation that eventually will include macroparticle simulations and experiments.
Electromagnetic field quantization in a linear dielectric medium
F. Kheirandish; M. Amooshahi
2005-11-13
By modeling a dielectric medium with two independent reservoirs, i.e., electric and magnetic reservoirs, the electromagnetic field is quantized in a linear dielectric medium consistently. A Hamiltonian is proposed from which using the Heisenberg equations, not only the Maxwell equations but also the structural equations can be obtained. Using the Laplace transformation, the wave equation for the electromagnetic vector potential is solved in the case of a homogeneous dielectric medium. Some examples are considered showing the applicability of the model to both absorptive and nonabsorptive dielectrics.
The 4th Concept Detector for the International Linear Collider
Sung Keun Park; Franco Grancagnolo; John Hauptman; Alexander Mikhailichenko; Nural Akchurin
2007-08-06
The 4th Concept detector presently being designed for the International Linear Collider introduces several innovations in order to achieve the necessary experimental goal of a detecter that is 2-to-10 times better than the already excellent SLC and LEP detectors. We introduce a dual-readout calorimeter system, a cluster counting drift chamber, and a second solenoid to return the magnetic flux without iron. We discuss particle identification, momentum and energy resolutions, and the machine-detector interface that together offer the possibility of a very high-performance detector for e^+e^-physics up to $\\sqrt{s} = 1$ TeV.
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Up: APS Storage Ring Parameters Previous: Longitudinal bunch profile and Magnets and Power Supplies Dipole Magnets and Power Supplies Value Dipole Number 80+1 No. of power...
SUPERCONDUCTING MAGNETIC ENERGY STORAGE
Hassenzahl, W.
2011-01-01
Superconducting 30-MJ Energy Storage Coil", Proc. 19 80 ASC,Superconducting Magnetic Energy Storage Plant", IEEE Trans.SlIperconducting Magnetic Energy Storage Unit", in Advances
Linear accelerator for radioisotope production
Hansborough, L.D.; Hamm, R.W.; Stovall, J.E.
1982-02-01
A 200- to 500-..mu..A source of 70- to 90-MeV protons would be a valuable asset to the nuclear medicine program. A linear accelerator (linac) can achieve this performance, and it can be extended to even higher energies and currents. Variable energy and current options are available. A 70-MeV linac is described, based on recent innovations in linear accelerator technology; it would be 27.3 m long and cost approx. $6 million. By operating the radio-frequency (rf) power system at a level necessary to produce a 500-..mu..A beam current, the cost of power deposited in the radioisotope-production target is comparable with existing cyclotrons. If the rf-power system is operated at full power, the same accelerator is capable of producing an 1140-..mu..A beam, and the cost per beam watt on the target is less than half that of comparable cyclotrons.
Cast dielectric composite linear accelerator
Sanders, David M. (Livermore, CA); Sampayan, Stephen (Manteca, CA); Slenes, Kirk (Albuquerque, NM); Stoller, H. M. (Albuquerque, NM)
2009-11-10
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.
Optical properties of gyroid structured materials: from photonic crystals to metamaterials
Dolan, James A.; Wilts, Bodo D.; Vignolini, Silvia; Baumberg, Jeremy J.; Steiner, Ullrich; Wilkinson, Timothy D.
2014-11-29
and transmission spectra of the gyroid photonic crystal vary significantly depending on the relative orientation of the crystal and the incoming light (Fig. 7a) [50, 52, 56]. Michielsen et al. in 2010 investigated the reflectivity of the gyroid photonic crystal cut... . in 2010 described how gyroid photonic crystals could rotate the plane of linearly polarised light (optical activity), how the scattered intensity differed for transverse magnetic and transverse electric linear polarisations (linear dichroism), and how...
Magnetic Fields and Large Scale Structure in a hot Universe. I. General Equations
E. Battaner; E. Florido; J. Jimenez-Vicente
1997-10-06
We consider that no mean magnetic field exists during this epoch, but that there is a mean magnetic energy associated with large-scale magnetic inhomogeneities. We study the evolution of these inhomogeneities and their influence on the large scale density structure, by introducing linear perturbations in Maxwell equations, the conservation of momentum-energy equation, and in Einstein field equations. The primordial magnetic field structure is time independent in the linear approximation, only being diluted by the general expansion, so that $\\vec{B}R^2$ is conserved in comoving coordinates. Magnetic fields have a strong influence on the formation of large-scale structure. Firstly, relatively low fields are able to generate density structures even if they were inexistent at earlier times. Second, magnetic fields act anisotropically more recently, modifying the evolution of individual density clouds. Magnetic flux tubes have a tendency to concentrate photons in filamentary patterns.
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)
2013-12-04
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.
The Electronic Journal of Linear Algebra. A publication of the International Linear Algebra Society.
Grudsky, Sergei
The Electronic Journal of Linear Algebra. A publication of the International Linear Algebra Society. Introduction and main results. Let lp n 1 p 1 be the linear space C n with the lp norm, kxkp = X j jxjjp 1=p
Ferrofluid spin-up flows from uniform and non-uniform rotating magnetic fields
Khushrushahi, Shahriar Rohinton
2010-01-01
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 ...
Seismic response of linear accelerators
Collette, C; Guinchard, M; Hauviller, C
2010-01-01
This paper is divided into two parts. The first part presents recent measurements of ground motion in the LHC tunnel at CERN. From these measurements, an update of the ground motion model currently used in accelerator simulations is presented. It contains new features like a model of the lateral motion and the technical noise. In the second part, it is shown how this model can be used to evaluate the seismic response of a linear accelerator in the frequency domain. Then, the approach is validated numerically on a regular lattice, taking the dynamic behavior of the machine alignment stage and the mechanical stabilization of the quadrupoles into account.
Linear Accelerator | Advanced Photon Source
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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would likeUniverseIMPACTThousand CubicResourcelogo and-E C H2015Tray and|Projects PagesLinear
Closed loop control of the induction heating process using miniature magnetic sensors
Bentley, Anthony E.; Kelley, John Bruce; Zutavern, Fred J.
2003-05-20
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).
Use of miniature magnetic sensors for real-time control of the induction heating process
Bentley, Anthony E. (Tijeras, NM); Kelley, John Bruce (Albuquerque, NM); Zutavern, Fred J. (Albuquerque, NM)
2002-01-01
A method of monitoring the process of induction heating a workpiece. 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 also be used to 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
2014-05-05
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.
Computational Geometry of Linear Threshold Functions
Abelson, Harold
1976-07-01
Linear threshold machines are defined to be those whose computations are based on the outputs of a set of linear threshold decision elements. The number of such elements is called the rank of the machine. An analysis ...
Linear Regression and Support Vector Regression
Shi, Qinfeng "Javen"
Linear Regression and Support Vector Regression Paul Paisitkriangkrai paulp@cs.adelaide.edu.au The University of Adelaide 18 August 2014 #12;Outlines · Regression overview · Linear regression · Support vector regression · Machine learning tools available #12;Regression Overview CLUSTERING CLASSIFICATION REGRESSION
Ultrashort Pulse Propagation in the Linear Regime
Wang, Jieyu
2010-07-14
First, we investigate the Bouguer-Lambert-Beer (BLB) law as applied to the transmission of ultrashort pulses through water in the linear absorption regime. We present a linear theory for propagation of ultrashort laser ...
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
Linear relaxations for transmission system planning
Taylor, Joshua A.
We apply a linear relaxation procedure for polynomial optimization problems to transmission system planning. The approach recovers and improves upon existing linear models based on the DC approximation. We then consider ...
High speed linear induction motor efficiency optimization
Johnson, Andrew P. (Andrew Peter)
2005-01-01
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 ...
Proceedings of the International Linear Collider Workshop
Proceedings of the International Linear Collider Workshop LCWS 2007 ILC 2007 Volume 1 Edited by Ariane Frey Sabine Riemann #12;Impressum Proceedings of the International Linear Collider Workshop LCWS
OPTIMIZING OF SUMS AND PRODUCTS OF LINEAR FRACTIONAL FUNCTIONS
OPTIMIZING OF SUMS AND PRODUCTS OF LINEAR FRACTIONAL FUNCTIONS UNDER LINEAR CONSTRAINTS JOACHIM of two linear fractional functions under linear constraints. Results of computational experiments. Fractional programming, composite objective functions, linear fractional functions, Charnes
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Zhu, S.; Cai, Y.; Rote, D.M.; Chen, S.S.
1998-01-01
Magnetic damping is one of the important parameters that control the response and stability of maglev systems. An experimental study to measure magnetic damping directly is presented. A plate attached to a permanent magnet levitated on a rotating drum was tested to investigate the effect of various parameters, such as conductivity, gap, excitation frequency, and oscillation amplitude, on magnetic damping. The experimental technique is capable of measuring all of the magnetic damping coefficients, some of which cannot be measured indirectly.
Batch-mode Supervised Learning Linear regression
Wehenkel, Louis
Batch-mode Supervised Learning Linear regression Applied inductive learning - Lecture 3 Louis (& Pierre Geurts)AIA... (1/19) #12;Batch-mode Supervised Learning Linear regression Batch-mode Supervised Learning Linear regression Least mean square error solution Regularization and algorithmics Residual
MINIMIZING COMMUNICATION IN NUMERICAL LINEAR ALGEBRA*
California at Berkeley, University of
MINIMIZING COMMUNICATION IN NUMERICAL LINEAR ALGEBRA* GREY BALLARD , JAMES DEMMEL , OLGA HOLTZ, i.e., essentially all direct methods of linear al- gebra. The proof works for dense or sparse our lower bound technique to compositions of linear algebra operations (like computing powers
Depolarization of backscattered linearly polarized light
Lacoste, David
Depolarization of backscattered linearly polarized light Luis Fernando Rojas-Ochoa Department of backscattered linearly polarized light with an extended photon dif- fusion formalism taking explicitly, the characteristic depolarization length for linearly polarized light, lp , is deduced. We investigate the dependence
Nanocomposite Magnets: Transformational Nanostructured Permanent Magnets
2010-10-01
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.
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)
2006-11-14
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.
Linearization of Moffat's Symmetric Complex Metric Gravity
Joakim Munkhammar
2009-09-19
In this paper we investigate a complex symmetric generalization of general relativity and in particular we investigate its linearized field equations. We begin by reviewing some basic definitions and structures in Moffat's symmetric complex metric field theory of gravity. We then move on to derive the linearized retarded complex field equations. In addition to this we also derive a linearization of Moffat's field equations based on the more rigorous Fermi coordinate approach. In conclusion it is shown that the linearized symmetric complex field equations leads to a complex form of gravitomagnetism. We also briefly review the gravitational wave equation from the source less linearized symmetric complex field equations and discuss some open problems.
Magnetic switch coupling to synchronize magnetic modulators
Reed, Kim W. (Albuquerque, NM); Kiekel, Paul (Albuquerque, NM)
1999-01-01
Apparatus for synchronizing the output pulses from a pair of magnetic switches. An electrically conductive loop is provided between the pair of switches with the loop having windlings about the core of each of the magnetic switches. The magnetic coupling created by the loop removes voltage and timing variations between the outputs of the two magnetic switches caused by any of a variety of factors. The only remaining variation is a very small fixed timing offset caused by the geometry and length of the loop itself.
Magnetic switch coupling to synchronize magnetic modulators
Reed, K.W.; Kiekel, P.
1999-04-27
Apparatus for synchronizing the output pulses from a pair of magnetic switches is disclosed. An electrically conductive loop is provided between the pair of switches with the loop having windings about the core of each of the magnetic switches. The magnetic coupling created by the loop removes voltage and timing variations between the outputs of the two magnetic switches caused by any of a variety of factors. The only remaining variation is a very small fixed timing offset caused by the geometry and length of the loop itself. 13 figs.
Reticle stage based linear dosimeter
Berger, Kurt W. (Livermore, CA)
2007-03-27
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.
2005-06-14
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.
Quantum Differential and Linear Cryptanalysis
Marc Kaplan; Gaëtan Leurent; Anthony Leverrier; María Naya-Plasencia
2015-10-20
Quantum computers, that may become available one day, will impact many scientific fields. Cryptography is certainly one of them since many asymmetric primitives would become insecure against an adversary with quantum capabilities. Cryptographers are already anticipating this threat by proposing and studying a number of potentially quantum-safe alternatives for those primitives. On the other hand, the situation of symmetric primitives which seem less vulnerable against quantum computing, has received much less attention. We need to prepare symmetric cryptography for the eventual arrival of the post-quantum world, as it is done with other cryptography branches. Cryptanalysis and security analysis are the only proper way to evaluate the security of symmetric primitives: our trust in specific ciphers relies on their ability to resist all known cryptanalysis tools. This requires a proper investigation of the toolkit of quantum cryptanalysis, that might include radically new attacks. This toolkit has not been much developed so far. In this paper, we study how some of the main cryptanalytic attacks behave in the post-quantum world. More specifically, we consider here quantum versions of differential and linear cryptanalysis. While running Grover's search algorithm on a quantum computer brings a quadratic speedup for brute-force attacks, we show that the situation is more subtle when considering specific cryptanalysis techniques. In particular, we give the quantum version of various classes of differential and linear attacks and show that the best attacks in the classical world do not necessarily lead to the best quantum ones. Some non-intuitive examples of application on ciphers LAC and KLEIN are provided.
Parr, Ronald
An Analysis of Linear Models, Linear Value-Function Approximation, and Feature Selection, Piscataway, NJ 08854 USA Abstract We show that linear value-function approxima- tion is equivalent to a form trees, neural networks, and linear functions. The first contribution of this paper shows that, when
Rutten, Jan
Motivation Introduction Linear maps as stream circuits Final semantics In conclusion Linear systems, coalgebraically Jan Rutten CWI & Vrije Universiteit Amsterdam CALCO 2007 #12;Motivation Introduction Linear maps as stream circuits Final semantics In conclusion Motivation Why linear systems, coalgebraically? Â· Very
ENGI 3423 Simple Linear Regression Page 12-01 Simple Linear Regression
George, Glyn
ENGI 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 for dealing with non-linear regression are available in the course text, but are beyond the scope
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
Controlling Magnetism at the Nanoscale
Wong, Jared
2012-01-01
157 A.2 Magnetism Unit Conversion148 A.1 Magnetism Unit ConversionA·m) Table A.1: Magnetism Unit Conversion Table Quantity A.1
Status of the NHMFL 60 tesla quasi-continuous magnet
Campbell, L.J.; Boenig, H.J.; Rickel, D.G.; Schilig, J.B.; Sims, J.R. [Los Alamos National Lab., NM (United States); Schneider-Muntau, H.J. [National High Magnetic Field Laboratory (NHMFL), Tallahassee, FL (United States)
1995-07-01
All components of the National High Magnetic Field Laboratory`s (NHMFL) 60 T quasi-continuous magnet are now under construction, with complete delivery and installation expected in early 1996. This research magnet has a cold bore of 32 mm and will produce a constant 60 tesla for 100 ms plus a wide variety of other pulse shapes such as linear ramps, steps, crowbar decays, and longer flat-tops at lower fields. Fabrication and testing of prototype coils are described along with the layout, construction status, and protection philosophy of the 400 MW power supply. Examples of simulated pulse shapes are shown.
Electronic and magnetic properties of iron doped zirconia: Theory and experiment
Debernardi, A. Sangalli, D.; Lamperti, A.; Cianci, E.; Lupo, P.; Casoli, F.; Albertini, F.; Nasi, L.
2014-05-07
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.
D. B. Papadopoulos
2003-12-23
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.
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
Nonmonotonic Magnetic Susceptibility of Dipolar Hard-Spheres at Low Temperature and Density
Sciortino, Francesco
component favoring the head-to-tail arrangement of the particles and the formation, at low T, of linearNonmonotonic Magnetic Susceptibility of Dipolar Hard-Spheres at Low Temperature and Density Sofia, the magnetic response of a dipolar hard sphere fluid at low temperatures and densities, in the region of strong
EE 202.3 (3L-3P alt weeks) Electric and Magnetic Fields and Circuits
Saskatchewan, University of
for magnetic circuits, principles of linear motors and generators The course is about 1/3 fields and 2EE 202.3 (3L-3P alt weeks) Electric and Magnetic Fields and Circuits Department of Electrical and Computer Engineering Fall 2015 Description: Further develops the theory and analysis of electric
Generation of shear Alfvn waves by a rotating magnetic field source: Three-dimensional simulations
Carter, Troy
an ambient magnetic field,57 SAW can transport energy efficiently. The SAW can drive plasma currents results with the experimental measurements and the linear shear Alfvén wave properties, namely that the energy of the Alfvén wave generated by the rotating magnetic field source is distributed between
Superconducting wiggler magnets for beam-emittance damping rings
Schoerling, Daniel
2012-01-01
Ultra-low emittance beams with a high bunch charge are necessary for the luminosity performance of linear electron-positron colliders, such as the Compact Linear Collider (CLIC). An effective way to create ultra-low emittance beams with a high bunch charge is to use damping rings, or storage rings equipped with strong damping wiggler magnets. The remanent field of the permanent magnet materials and the ohmic losses in normal conductors limit the economically achievable pole field in accelerator magnets operated at around room temperature to below the magnetic saturation induction, which is 2.15 T for iron. In wiggler magnets, the pole field in the center of the gap is reduced further like the hyperbolic cosine of the ratio of the gap size and the period length multiplied by pi. Moreover, damping wiggler magnets require relatively large gaps because they have to accept the un-damped beam and to generate, at a small period length, a large magnetic flux density amplitude to effectively damp the beam emittance....
Magnetic field restructuring associated with two successive solar eruptions
Wang, Rui; Liu, Ying D.; Yang, Zhongwei; Hu, Huidong
2014-08-20
We examine two successive flare eruptions (X5.4 and X1.3) on 2012 March 7 in the NOAA active region 11429 and investigate the magnetic field reconfiguration associated with the two eruptions. Using an advanced non-linear force-free field extrapolation method based on the SDO/HMI vector magnetograms, we obtain a stepwise decrease in the magnetic free energy during the eruptions, which is roughly 20%-30% of the energy of the pre-flare phase. We also calculate the magnetic helicity and suggest that the changes of the sign of the helicity injection rate might be associated with the eruptions. Through the investigation of the magnetic field evolution, we find that the appearance of the 'implosion' phenomenon has a strong relationship with the occurrence of the first X-class flare. Meanwhile, the magnetic field changes of the successive eruptions with implosion and without implosion were well observed.
Performance of An Adjustable Strength Permanent Magnet Quadrupole
Gottschalk, S.C.; DeHart, T.E.; Kangas, K.W.; /STI Optronics, Bellevue; Spencer, C.M.; /SLAC; Volk, J.T.; /Fermilab
2006-03-01
An adjustable strength permanent magnet quadrupole suitable for use in Next Linear Collider has been built and tested. The pole length is 42cm, aperture diameter 13mm, peak pole tip strength 1.03Tesla and peak integrated gradient * length (GL) is 68.7 Tesla. This paper describes measurements of strength, magnetic CL and field quality made using an air bearing rotating coil system. The magnetic CL stability during -20% strength adjustment proposed for beam based alignment was < 0.2 microns. Strength hysteresis was negligible. Thermal expansion of quadrupole and measurement parts caused a repeatable and easily compensated change in the vertical magnetic CL. Calibration procedures as well as CL measurements made over a wider tuning range of 100% to 20% in strength useful for a wide range of applications will be described. The impact of eddy currents in the steel poles on the magnetic field during strength adjustments will be reported.
Magnetic Graphene Nanohole Superlattices
Yu, Decai; Liu, Miao; Liu, Wei; Liu, Feng
2008-01-01
We investigate the magnetic properties of nano-holes (NHs) patterned in graphene using first principles calculations. We show that superlattices consisting of a periodic array of NHs form a new family of 2D crystalline "bulk" magnets whose collective magnetic behavior is governed by inter-NH spin-spin interaction. They exhibit long-range magnetic order well above room temperature. Furthermore, magnetic semiconductors can be made by doping magnetic NHs into semiconducting NH superlattices. Our findings offer a new material system for fundamental studies of spin-spin interaction and magnetic ordering in low dimensions, and open up the exciting opportunities of making engineered magnetic materials for storage media and spintronics applications.
Magnetic assisted statistical assembly
Cheng, Diana I
2008-01-01
The objective of this thesis is to develop a process using magnetic forces to assemble micro-components into recesses on silicon based integrated circuits. Patterned SmCo magnetic thin films at the bottom of recesses are ...
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...
Automating approximate Bayesian computation by local linear regression
Thornton, Kevin R
2009-01-01
computation by local linear regression Kevin R Thorntonof ABC based on using a linear regression to approximate theimplements the local linear-regression approach to ABC. The
Multi-Stage Bunch Compressors for the International Linear Collider
Tenenbaum, Peter G.; Raubenheimer, Tor O.; Wolski, Andrzej
2005-01-01
FOR THE INTERNATIONAL LINEAR COLLIDER ? P. Tenenbaum † ,goals, the International Linear Collider (ILC) requires acompressors for the International Linear Collider. Each of
Linear stability of magnetohydrodynamic flow in a perfectly conducting rectangular duct
Priede, J?nis; Molokov, Sergei
2011-01-01
We analyse numerically the linear stability of a liquid metal flow in a rectangular duct with perfectly electrically conducting walls subject to a uniform transverse magnetic field. A vector stream function formulation is used with Chebyshev collocation method to solve the eigenvalue problem for small-amplitude perturbations. A relatively weak magnetic field is found to render the flow linearly unstable as two weak jets appear close to the centre of the duct at the Hartmann number Ha \\approx 9.6. In a sufficiently strong magnetic field, the instability following the jets becomes confined in the layers of characteristic thickness \\delta \\sim Ha^{-1/2} located at the walls parallel to the magnetic field. In this case the instability is determined by \\delta, which results in both the critical Reynolds and wavenumbers numbers scaling as \\sim \\delta^{-1}. Instability modes can have one of the four different symmetry combinations along and across the magnetic field. The most unstable is a pair of modes with an even...
Triggering for Magnetic Field Measurements of the LCLS Undulators
Hacker, Kirsten
2010-12-13
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.
Rotating superconductor magnet for producing rotating lobed magnetic field lines
Hilal, Sadek K. (Englewood Cliffs, NJ); Sampson, William B. (Bellport, NY); Leonard, Edward F. (Leonia, NJ)
1978-01-01
This invention provides a rotating superconductor magnet for producing a rotating lobed magnetic field, comprising a cryostat; a superconducting magnet in the cryostat having a collar for producing a lobed magnetic field having oppositely directed adjacent field lines; rotatable support means for selectively rotating the superconductor magnet; and means for energizing the superconductor magnet.
Magnetic Fields Analogous to electric field, a magnet
Bertulani, Carlos A. - Department of Physics and Astronomy, Texas A&M University
Magnetic Fields Analogous to electric field, a magnet produces a magnetic field, B Set up a B field two ways: Moving electrically charged particles Current in a wire Intrinsic magnetic field Basic) Opposite magnetic poles attract like magnetic poles repel #12;Like the electric field lines
Walker, Thad Gilbert; Lancor, Brian Robert; Wyllie, Robert
2014-04-15
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
2013-05-14
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.
Metallic Magnetic Hetrostructures
Leung, Chi Wah
.2.2 Domains and magnetization processes 1.2.2.1 Domains and domain walls 1.2.2.2 Magnetization reversal and hysteresis 1.2.2.3 Modelling of magnetization process 1.3 Sputter deposition of thin films in this project 1.3.1 Substrate preparation 1.3.2 ‘UFO...
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)
2013-04-15
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.
The origin, evolution and signatures of primordial magnetic fields
Kandaswamy Subramanian
2015-04-09
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, including current constraints from Planck, are discussed. After recombination, primordial magnetic fields could strongly influence structure formation, especially on dwarf galaxy scales. The resulting signatures on reionization, the redshifted 21 cm line, weak lensing and the Lyman-$\\alpha$ forest are outlined. Constraints from radio and $\\gamma$-ray astronomy are summarized. Astrophysical batteries and the role of dynamos in reshaping the primordial field are briefly considered. The review ends with some final thoughts on primordial magnetic fields.
Studies on the Interaction of DGCR8 with the Cofactor Heme.
Barr, Robert Ian
2012-01-01
magnetic circular dichroism, and electron paramagnetic resonance spectra of the DGCR8-heme complex suggest a ferric heme bearing
International Workshop on Linear Colliders 2010
None
2011-10-06
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
Peterson, J. L.; Hammet, G. W.; Mikkelsen, D. R.; Yuh, H. Y.; Candy, J.; Guttenfelder, W.; Kaye, S. M.; LeBlanc, B.
2011-05-11
The first nonlinear gyrokinetic simulations of electron internal transport barriers (e-ITBs) in the National Spherical Torus Experiment show that reversed magnetic shear can suppress thermal transport by increasing the nonlinear critical gradient for electron-temperature-gradient-driven turbulence to three times its linear critical value. An interesting feature of this turbulence is non- linearly driven off-midplane radial streamers. This work reinforces the experimental observation that magnetic shear is likely an effective way of triggering and sustaining e-ITBs in magnetic fusion devices.
International Linear Collider Technical Design Report - Volume...
Office of Scientific and Technical Information (OSTI)
Linear Collider Technical Design Report - Volume 2: Physics Baer, Howard; Barklow, Tim; Fujii, Keisuke; Gao, Yuanning; Hoang, Andre; Kanemura, Shinya; List, Jenny; Logan, Heather...
Ultra-high vacuum photoelectron linear accelerator
Yu, David U.L.; Luo, Yan
2013-07-16
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.
Elastic Wave Behavior Across Linear Slip Interfaces
Schoenberg, M.
Reflection and transmission coefficients for harmonic plane waves incident at arbitrary angles upon a plane linear slip interface are computed in terms of the.
JLab Supports International Linear Collider Cavity Development...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Supports International Linear Collider Cavity Development Work NEWPORT NEWS, Va. Feb. 12, 2008 - It's not often that major-league baseball and nuclear physics get to share the...
Math 265, Section 32: Elementary Linear Algebra
Math 265, Section 32: Elementary Linear Algebra. Course Information. Professor: Kiril Datchev Email: kdatchev@purdue.edu. Lectures: Tuesday and Thursday ...
Linear Algebra (MATH 511, Spring 2012)
Linear Algebra (MATH 511, Spring 2012). Teacher: Alexandre Eremenko OFFICE HOURS: Math 450 Thursday 1:30-2:30 + by appointment PHONE: (765)
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...
The Linear Engine Pathway of Transformation
Broader source: Energy.gov [DOE]
This poster highlights the major milestones in the history of the linear engine in terms of technological advances, novel designs, and economic/social impact.
Schrijver, Karel
-like magnetically active stars, by combining empirical relationships between rotation rate and mass loss, angular-star wind scales linearly with the unsigned surface magnetic flux density, as does that needed to heat magnetic field with the embedded coronal plasma, which is heated throughout the corona, and accelerated
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)
2013-11-15
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.
Magnetically attached sputter targets
Makowiecki, D.M.; McKernan, M.A.
1994-02-15
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.
Implicit Methods for the Magnetohydrodynamic Description of Magnetically Confined Plasmas
S.C. Jardin
2010-09-28
Implicit algorithms are essential for predicting the slow growth and saturation of global instabilities in today’s magnetically confined fusion plasma experiments. Present day algorithms for obtaining implicit solutions to the magnetohydrodynamic (MHD) equations for highly magnetized plasma have their roots in algorithms used in the 1960s and 1970s. However, today’s computers and modern linear and non?linear solver techniques make practical much more comprehensive implicit algorithms than were previously possible. Combining these advanced implicit algorithms with highly accurate spatial representations of the vector fields describing the plasma flow and magnetic fields and with improved methods of calculating anisotropic thermal conduction now makes possible simulations of fusion experiments using realistic values of plasma parameters and actual configuration geometry.
The chiral magnetic nanomotors
Morozov, Konstantin I
2013-01-01
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.
Bettarini, Lapo [Katholieke Universiteit Leuven, Centrum voor Plasma Astrofysica, Celestijnenlaan 200B, B-3001 Leuven (Belgium); Dipartimento di Astronomia e Scienza dello Spazio, Universita degli Studi di Firenze, Largo E. Fermi, 2, I-50125 Firenze (Italy); Landi, Simone [Dipartimento di Astronomia e Scienza dello Spazio, Universita degli Studi di Firenze, Largo E. Fermi, 2, I-50125 Firenze (Italy); Velli, Marco [Dipartimento di Astronomia e Scienza dello Spazio, Universita degli Studi di Firenze, Largo E. Fermi, 2, I-50125 Firenze (Italy); Jet Propulsion Laboratory, 4800 Oak Grove Drive, Pasadena, California 91109 (United States); Londrillo, Pasquale [INAF Osservatorio Astronomico di Bologna, via C. Ranzani 1, I-40127 Bologna (Italy)
2009-06-15
The problem of three-dimensional combined magnetic and velocity shear driven instabilities of a compressible magnetized jet modeled as a plane neutral/current double vortex sheet in the framework of the resistive magnetohydrodynamics is addressed. The resulting dynamics given by the stream+current sheet interaction is analyzed and the effects of a variable geometry of the basic fields are considered. Depending on the basic asymptotic magnetic field configuration, a selection rule of the linear instability modes can be obtained. Hence, the system follows a two-stage path developing either through a fully three-dimensional dynamics with a rapid evolution of kink modes leading to a final turbulent state, or rather through a driving two-dimensional instability pattern that develops on parallel planes on which a reconnection+coalescence process takes place.
Linear optics, Raman scattering, and spin noise spectroscopy
Glazov, M M
2015-01-01
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.
W. B. Vasantha Kandasamy; Florentin Smarandache
2009-02-01
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.
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
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
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
Soft materials for linear electromechanical energy conversion
Antal Jakli; Nandor Eber
2014-07-29
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.
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)
2014-04-20
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.
Assumptions that imply quantum dynamics is linear
Thomas F. Jordan
2006-01-26
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.
Qiu, Li
with permanent-magnet rotary motors and rotary to linear couplers. Though this method is the most widely used was with the Department of Electrical Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong. He is now Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong (e-mail: eencheun@polyu. edu.hk). L. Qiu
Neal, R B
1956-01-01
The Stanford Mark III linear accelerator and speculations concerning the multi-Bev applications of electron linear accelerators
Non-linear transformer modeling and simulation
Archer, W.E.; Deveney, M.F.; Nagel, R.L.
1994-08-01
Transformers models for simulation with Pspice and Analogy`s Saber are being developed using experimental B-H Loop and network analyzer measurements. The models are evaluated for accuracy and convergence using several test circuits. Results are presented which demonstrate the effects on circuit performance from magnetic core losses eddy currents and mechanical stress on the magnetic cores.
Linear Transformations In this Chapter, we will define the notion of a linear transformation between
Fournier, John J.F.
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
PERVASIVE LINEAR POLARIZATION SIGNALS IN THE QUIET SUN
Bellot Rubio, L. R.; Orozco Suarez, D.
2012-09-20
This paper investigates the distribution of linear polarization signals in the quiet-Sun internetwork using ultra-deep spectropolarimetric data. We reduce the noise of the observations as much as is feasible by adding single-slit measurements of the Zeeman-sensitive Fe I 630 nm lines taken by the Hinode spectropolarimeter. The integrated Stokes spectra are employed to determine the fraction of the field of view covered by linear polarization signals. We find that up to 69% of the quiet solar surface at disk center shows Stokes Q or U profiles with amplitudes larger than 0.032% (4.5 times the noise level of 7 Multiplication-Sign 10{sup -5} reached by the longer integrations). The mere presence of linear polarization in most of the quiet Sun implies that the weak internetwork fields must be highly inclined, but we quantify this by inverting those pixels with Stokes Q or U signals well above the noise. This allows for a precise determination of the field inclination, field strength, and field azimuth because the information carried by all four Stokes spectra is used simultaneously. The inversion is performed for 53% of the observed field of view at a noise level of 1.3 Multiplication-Sign 10{sup -4} I{sub c}. The derived magnetic distributions are thus representative of more than half of the quiet-Sun internetwork. Our results confirm the conclusions drawn from previous analyses using mainly Stokes I and V: internetwork fields are very inclined, but except in azimuth they do not seem to be isotropically distributed.
Passive magnetic bearing system
Post, Richard F.
2014-09-02
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.
Light propagation in local and linear media: Fresnel-Kummer wave surfaces with 16 singular points
Favaro, Alberto
2015-01-01
It is known that the Fresnel wave surfaces of transparent biaxial media have 4 singular points, located on two special directions. We show that, in more general media, the number of singularities can exceed 4. In fact, a highly symmetric linear material is proposed whose Fresnel surface exhibits 16 singular points. Because, for every linear material, the dispersion equation is quartic, we conclude that 16 is the maximum number of singularities. The identity of Fresnel and Kummer surfaces, which holds true for media with a certain symmetry (zero skewon piece), provides an elegant interpretation of the results. We describe a metamaterial realization for our linear medium with 16 singular points. It is found that an appropriate combination of metal bars, split-ring resonators, and magnetized particles can generate the correct permittivity, permeability, and magnetoelectric moduli. Lastly, we discuss the arrangement of the singularities in terms of Kummer's (16,6)-configuration of points and planes. An investigat...
Tsai, Cheng-Ying; Li, Rui; Tennant, Chris
2015-01-01
As is known, microbunching instability (MBI) has been one of the most challenging issues in designs of magnetic chicanes for short-wavelength free-electron lasers or linear colliders, as well as those of transport lines for recirculating or energy recovery linac machines. To more accurately quantify MBI in a single-pass system and for more complete analyses, we further extend and continue to increase the capabilities of our previously developed linear Vlasov solver [1] to incorporate more relevant impedance models into the code, including transient and steady-state free-space and/or shielding coherent synchrotron radiation (CSR) impedances, the longitudinal space charge (LSC) impedances, and the linac geometric impedances with extension of the existing formulation to include beam acceleration [2]. Then, we directly solve the linearized Vlasov equation numerically for microbunching gain amplification factor. In this study we apply this code to a beamline lattice of transport arc [3] following an upstream linac...
Kissock, J. K.; Haberl, J. S.; Claridge, D. E.
2002-11-01
This report summarizes the results of ASHRAE Research Project 1050: Development of a Toolkit for Calculating Linear, Change-Point Linear and Multiple Linear Inverse Building Energy Analysis Models. The Inverse Modeling ...
Christiansen, D.W.; Brown, W.F.
1984-01-01
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, D.J.; Richardson, J.G.; Albano, R.K.; Morrison, J.L. Jr.
1995-11-28
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. 2 figs.
Magnetic Braids Anthony Yeates
Dundee, University of
function Main result Conclusion Examples 1. Magnetic loops in the solar corona. NASA Solar Dynamics of the potential a Hi,j a x = 2 a xi At each neutral p Hi,j a . The magnet function and it co field topology. Magnetic helicity H = V AÂ·BdV, B = Ã?A is a well-known global ideal invariant in a closed
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)
2005-01-01
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.
Koide, T.; Iwase, A. [Department of Materials Science, Osaka Prefecture University, Sakai, Osaka 599-8531 (Japan); Saitoh, Y. [Japan Atomic Energy Agency, Takasaki, Gunma 370-1292 (Japan); Sakamaki, M.; Amemiya, K. [High Energy Accelerator Research Organization, Tsukuba, Ibaraki 305-0801 (Japan); Matsui, T., E-mail: t-matsui@21c.osakafu-u.ac.jp [Research Organization for the 21st Century, Osaka Prefecture University Sakai, Osaka 599-8531 (Japan)
2014-05-07
The effect of energetic cluster ion beam irradiation on magnetic and structural properties of FeRh thin films have been investigated. The cluster ions used in the present studies consist of a few gold atoms with the energy of 1.67?MeV/gold atom. Saturation magnetization of the sample irradiated with Au3 cluster ion beam (280?emu/cc) is larger than that for the irradiated sample with Au1 ion beam (240?emu/cc) for the same irradiation ion fluence. These results can also be confirmed by the X-ray magnetic circular dichroism (XMCD) measurement; the XMCD signal for Au3 cluster ion irradiation is larger than that for Au1 ion irradiation. Since the ion beam irradiation induced magnetization of FeRh is significantly correlated with the amount of the lattice defects in the samples, cluster ion beam irradiation can be considered to effectively introduce the lattice defects in B2-type FeRh rather than the single ion beam. Consequently, cluster ion irradiation is better than single ion irradiation for the viewpoint of saturation magnetization, even if the same irradiation energy is deposited in the samples.
Magnetically leviated superconducting bearing
Weinberger, Bernard R. (Avon, CT); Lynds, Jr., Lahmer (Glastonbury, CT)
1993-01-01
A magnetically levitated superconducting bearing includes a magnet (2) mounted on a shaft (12) that is rotatable around an axis of rotation and a Type II superconductor (6) supported on a stator (14) in proximity to the magnet (2). The superconductor (6) is positioned so that when it is cooled to its superconducting state in the presence of a magnetic field, it interacts with the magnet (2) to produce an attractive force that levitates the magnet (2) and supports a load on the shaft (12). The interaction between the superconductor (6) and magnet(2) also produces surface screening currents (8) that generate a repulsive force perpendicular to the load. The bearing also has means for maintaining the superconductor at a temperature below its critical temperature (16, 18). The bearing could also be constructed so the magnet (2) is supported on the stator (14) and the superconductor (6) is mounted on the shaft (12). The bearing can be operated by cooling the superconductor (6) to its superconducting state in the presence of a magnetic field.
Royet, J.
2010-01-01
76SFOOO98. MAGNET CABLE MANUFACTURING John Royet Lawrenceused in this cable manufacturing are made of superconductingapplied during manufacturing. 2.2 Twist The composite
Magnetic flux concentrations from turbulent stratified convection
Käpylä, P J; Kleeorin, N; Käpylä, M J; Rogachevskii, I
2015-01-01
(abridged) Context: The mechanisms that cause the formation of sunspots are still unclear. Aims: We study the self-organisation of initially uniform sub-equipartition magnetic fields by highly stratified turbulent convection. Methods: We perform simulations of magnetoconvection in Cartesian domains that are $8.5$-$24$ Mm deep and $34$-$96$ Mm wide. We impose either a vertical or a horizontal uniform magnetic field in a convection-driven turbulent flow. Results: We find that super-equipartition magnetic flux concentrations are formed near the surface with domain depths of $12.5$ and $24$ Mm. The size of the concentrations increases as the box size increases and the largest structures ($20$ Mm horizontally) are obtained in the 24 Mm deep models. The field strength in the concentrations is in the range of $3$-$5$ kG. The concentrations grow approximately linearly in time. The effective magnetic pressure measured in the simulations is positive near the surface and negative in the bulk of the convection zone. Its ...
Optically isolated signal coupler with linear response
Kronberg, James W. (Aiken, SC)
1994-01-01
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).
MAGNETIC HELICITY IN THE DISSIPATION RANGE OF STRONG IMBALANCED TURBULENCE
Markovskii, S. A.; Vasquez, Bernard J. E-mail: bernie.vasquez@unh.edu
2013-05-01
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.
Electric-Magnetic Duality and the Heavy Quark Potential
M. Baker
1996-09-05
We use the assumption of electric-magnetic duality to express the heavy quark potential in QCD in terms of a Wilson Loop $W_{eff}(\\Gamma)$ determined by the dynamics of a dual theory which is weakly coupled at long distances. The classical approximation gives the leading contribution to $W_{eff}(\\Gamma)$ and yields a velocity dependent heavy quark potential which for large $R$ becomes linear in $R$, and which for small $R$ approaches lowest order perturbative QCD. The corresponding long distance interaction between color magnetic monopoles is governed by a Yukawa potential. As a consequence the magnetic interaction between the color magnetic moments of the quarks is exponentially damped. The semi-classical corrections to $W_{eff}(\\Gamma)$ due to fluctuations of the classical flux tube should lead to an effective string theory free from the conformal anomaly.
CLIQ. A new quench protection technology for superconducting magnets
Ravaioli, Emmanuele; ten Kate, H H J
CLIQ, the Coupling-Loss Induced Quench system, is a new method for protecting superconducting magnets after a sudden transition to the normal state. It offers significant advantages over the conventional technology due to its effective mechanism for heating the superconductor relying on coupling loss and its robust electrical design, which makes it more reliable and less interfering with the coil winding process. The analysis of the electro-magnetic and thermal transients during and after a CLIQ discharge allows identifying the system parameters that affect the system performance and defining guidelines for implementing this technology on coils of various characteristics. Most existing superconducting magnets can be protected by CLIQ as convincingly shown by test results performed on magnets of different sizes, superconductor types, geometries, cables and strand parameters. Experimental results are successfully reproduced by means of a novel technique for modeling non-linear dynamic effects in superconducting...
Molten metal feed system controlled with a traveling magnetic field
Praeg, Walter F. (Palos Park, IL)
1991-01-01
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.
Magnetic helicity signature produced by cross-field 2D turbulence
Markovskii, S. A.; Vasquez, Bernard J.
2013-06-13
Hybrid numerical simulations of freely decaying 2D turbulence are presented. The background magnetic field is perpendicular to the simulation plane, which eliminates linear kinetic Alfven waves from the system. The normalized magnetic helicity of the initial large-scale fluctuations is zero, while the normalized cross-helicity is not. 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.
Self-compression of intense short laser pulses in relativistic magnetized plasma
Olumi, M.; Maraghechi, B.
2014-11-15
The compression of a relativistic Gaussian laser pulse in a magnetized plasma is investigated. By considering relativistic nonlinearity and using non-linear Schrödinger equation with paraxial approximation, a second-order differential equation is obtained for the pulse width parameter (in time) to demonstrate the longitudinal pulse compression. The compression of laser pulse in a magnetized plasma can be observed by the numerical solution of the equation for the pulse width parameter. The effects of magnetic field and chirping are investigated. It is shown that in the presence of magnetic field and negative initial chirp, compression of pulse is significantly enhanced.
MULTI-SPACECRAFT OBSERVATIONS OF LINEAR MODES AND SIDEBAND WAVES IN ION-SCALE SOLAR WIND TURBULENCE
Perschke, Christopher; Motschmann, Uwe; Narita, Yasuhito; Glassmeier, Karl-Heinz
2014-10-01
In the scenario of weak turbulence, energy is believed to be cascaded from smaller to larger wave numbers and frequencies due to weak wave-wave interactions. Based on its perturbative treatment one may regard plasma turbulence as a superposition of linear modes (or normal modes) and sideband waves (or nonlinear modes). In this study, we use magnetic field and plasma measurements of nine solar wind events obtained by the Cluster spacecraft and make extensive use of a high-resolution wave vector analysis method, the Multi-point Signal Resonator technique, to find frequencies and wave vectors of discrete modes on ion kinetic scales in the plasma rest frame. The primarily unstructured wave observations in the frequency-wave number diagram are classified into three distinct linear modes (proton Bernstein modes, helium-alpha Bernstein modes, and kinetic Alfvén waves) and the sideband waves by comparing with the dispersion relations derived theoretically from linear Vlasov theory using observational values of the plasma parameter beta and the propagation angle from the mean magnetic field. About 60% of the observed discrete modes can be explained by the linear modes, primarily as the proton Bernstein and the kinetic Alfvén waves, within the frequency uncertainties, while the rest of the population (about 40%) cannot be classified as linear modes due to the large deviation from dispersion relations. We conclude that both the linear modes and sideband wave components are needed to construct the wave picture of solar wind turbulence on ion-kinetic scales.
Kim, Minseok; Kim, Sanghoon; Ko, Jungho; Hong, Jongill
2015-03-09
The contribution of each interface of the MgO/Co/Pd trilayer to the perpendicular magnetic anisotropy (PMA) was studied by changing chemical and crystalline structures through annealing. We found that volumetric anisotropy in the MgO/Co/Pd trilayer was significantly increased due to enhanced magnetoelastic anisotropy caused by stress built up most likely at the MgO/Co interface during annealing. When the trilayer was annealed at 400?°C, the alloy formation at the Co/Pd interface additionally increased the volumetric anisotropy. Our x-ray magnetic circular dichroism study supported that those structural modifications led to an increase in the orbital moment through spin-orbit coupling (SOC) along the film normal two times larger than that of the as-deposited trilayer, thereby enhancing PMA greatly. Our experimental results prove that the Co/Pd interface, rather than the MgO/Co interface, plays an essential role in inducing strong PMA in the trilayer. The precise investigation of annealing effect on both volumetric and interfacial anisotropies can provide a methodological solution to improve the SOC of the trilayer that can serve as the core unit of spintronic devices.
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 ...
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
2014-12-22
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.
GROUP SPARSITY VIA LINEAR-TIME PROJECTION
2008-08-01
Jul 31, 2008 ... linear-time algorithm for Euclidean projection onto the l1- and group l1-norm ..... of 128 entries and eight non-zero groups, and additive noise si ...
Photon Linear Collider Gamma-Gamma Summary
Gronberg, J
2012-02-27
High energy photon - photon collisions can be achieved by adding high average power short-pulse lasers to the Linear Collider, enabling an expanded physics program for the facility. The technology required to realize a photon linear collider continues to mature. Compton back-scattering technology is being developed around the world for low energy light source applications and high average power lasers are being developed for Inertial Confinement Fusion.
Mcdonald, Ross D; Singleton, John; Lancaster, Tom; Goddard, Paul; Manson, Jamie
2011-01-14
We nave measured the high-field magnetization of a number of Ni-based metal-organic molecular magnets. These materials are self-assembly coordination polymers formed from transition metal ions and organic ligands. The chemistry of the compounds is versatile allowing many structures with different magnetic properties to be formed. These studies follow on from previous measurements of the Cu-based analogues in which we showed it was possible to extract the exchange parameters of low-dimensional magnets using pulsed magnetic fields. In our recent experiments we have investigated the compound (Ni(HF{sub 2})(pyz){sub 2})PF{sub 6}, where pyz = pyrazine, and the Ni-ions are linked in a quasi-two-dimensional (Q2D) square lattice via the pyrazine molecules, with the layers held together by HF{sub 2} ligands. We also investigated Ni(NCS){sub 2}(pyzdo){sub 2}, where pyzdo = pyrazine dioxide. The samples are grown at Eastern Washington University using techniques described elsewhere. Measurements are performed at the pulsed magnetic field laboratory in Los Alamos. The magnetization of powdered samples is determined using a compensated coil magnetometer in a 65 T short pulse magnet. Temperatures as low as 500 mK are achievable using a {sup 3}He cryostat. The main figure shows the magnetization of the spin-1 [Ni(HF{sub 2})(pyz){sub 2}]PF{sub 6} compound at 1.43 K. The magnetization rises slowly at first, achieving a rounded saturation whose midpoint is around 19 T. A small anomaly is also seen in the susceptibility at low fields ({approx}3 T), which might be attributed to a spin-flop transition. In contrast, the spin-1/2 [Cu(HF{sub 2})(pyz){sub 2}]PF{sub 6} measured previously has a saturation magnetization of 35.5 T and a strongly concave form of M(B) below this field. This latter compound was shown to be a good example of a Q2D Heisenberg antiferromagnet with the strong exchange coupling (J{sub 2D} = 12.4 K, J{sub {perpendicular}}/J{sub 2D} {approx} 10{sup -2}) directed along the Cu-pyz-Cu directions. The structure of the two compounds is similar, but in the case of the Cu-compound the Cu-Cu pathways are linear, whereas in the Ni-compound they are kinked. The pulsed-field data combined with information from temperature-dependent susceptibility, muon-spin rotation, electron-spin resonance and ligand-field calculations suggest that, far from being magnetically Q2D, the Ni-compound is fairly one-dimensional with the dominant exchange (J{sub 1D} = 3.1 K and J{sub {perpendicular}}/J{sub 1D} = 0.63) directed along the Ni-FHF-Ni direction. Ni(NCS){sub 2}(pyzdo){sub 2} was also investigated. Previous ultra-high field measurements using the 100 T magnet have shown that this compound has a saturation field close to 80 T. The purpose of the present studies is to map out the phase diagram of this material at mid-range fields. The data are shown in the inset to the figure. This continuing project probes the ability of organic ligands to mediate magnetic exchange, the link between structure, dimensionality and bulk magnetic properties, as well as the role of spin number in quantum magnets. Ultimately the investigations aim to determine to what extent it is possible to produce self-assembly molecular materials with tailor-made magnetic characteristics.
Perez Rojas, H.; Rodriguez Querts, E. [Instituto de Cibernetica, Matematica y Fisica, Calle E No. 309, esq. a 15 Vedado, C. Havana (Cuba)
2006-06-19
We study vacuum properties in a strong magnetic field as the zero temperature and zero density limit of quantum statistics. For charged vector bosons (W bosons) the vacuum energy density diverges for B > B{sub c} = m{sub w}{sup 2}/e, leading to vacuum instability. A logarithmic divergence of vacuum magnetization is found for B = Bc, which suggests that if the magnetic field is large enough, it is self-consistently maintained, and this mechanism actually prevents B from reaching the critical value Bc. For virtual neutral vector bosons bearing an anomalous magnetic moment, the instability of the ground state for B > B{sub c}{sup '} = m{sub n}{sup 2}/q also leads to the vacuum energy density divergence for fields B > B{sub c}{sup '} and to the magnetization divergence for B B{sub c}{sup '}. The possibility of virtual electron-positron pairs bosonization in strong magnetic field and the applicability of the neutral bosons model to describe the virtual positronium behavior in a magnetic field are discussed. We conjecture that this could lead to vacuum self-magnetization in QED.
Passive magnetic bearing configurations
Post, Richard F. (Walnut Creek, CA)
2011-01-25
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.
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
A New Algorithm for Linear Programming
Dhananjay P. Mehendale
2015-03-28
In this paper we propose two types of new algorithms for linear programming. The first type of these new algorithms uses algebraic methods while the second type of these new algorithms uses geometric methods. The first type of algorithms is based on treating the objective function as a parameter. In this method, we form a matrix using coefficients in the system of equations consisting objective equation and equations obtained from inequalities defining constraint by introducing slack/surplus variables. We obtain reduced row echelon form for this matrix containing only one variable, namely, the objective function itself as an unknown parameter. We analyse this matrix in the reduced row echelon form and develop a clear cut method to find the optimal solution for the problem at hand, if and when it exists. We see that the entire optimization process can be developed through the proper analysis of the said matrix in the reduced row echelon form. The second type of algorithms that we propose for linear programming are inspired by geometrical considerations. All these algorithms pursue common aim of approaching closer and closer to centroid or some centrally located interior point for speeding up the process of reaching an optimal solution! We then proceed to show that the algebraic method developed above for linear programming naturally extends to non-linear and integer programming problems. For non-linear and integer programming problems we use the technique of Grobner bases and the methods of solving linear Diophantine equations respectively.
Lectures on Linear Algebra over Division Ring
Aleks Kleyn
2014-10-11
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.
Plasticity-Induced Magnetization in Amorphous Magnetic Solids
H. George E. Hentschel; Itamar Procaccia; Bhaskar Sen Gupta
2013-10-15
Amorphous magnetic solids, like metallic glasses, exhibit a novel effect: the growth of magnetic order as a function of mechanical strain under athermal conditions in the presence of a magnetic field. The magnetic moment increases in steps whenever there is a plastic event. Thus plasticity induces the magnetic ordering, acting as the effective noise driving the system towards equilibrium. We present results of atomistic simulations of this effect in a model of a magnetic amorphous solid subjected to pure shear and a magnetic field. To elucidate the dependence on external strain and magnetic field we offer a mean-field theory that provides an adequate qualitative understanding of the observed phenomenon.
Thorn, Craig E. (Wading River, NY); Chasman, Chellis (Setauket, NY); Baltz, Anthony J. (Coram, NY)
1984-04-24
An improved magnet which more easily provides a radially increasing magnetic field, as well as reduced fringe field and requires less power for a given field intensity. The subject invention comprises a pair of spaced, opposed magnetic poles which further comprise a pair of pole roots, each having a pole tip attached to its center. The pole tips define the gap between the magnetic poles and at least a portion of each pole tip is separated from its associated pole root. The separation begins at a predetermined distance from the center of the pole root and increases with increasing radial distance while being constant with azimuth within that portion. Magnets in accordance with the subject invention have been found to be particularly advantageous for use in large isochronous cyclotrons.
Thorn, C.E.; Chasman, C.; Baltz, A.J.
1981-11-19
An improved magnet more easily provides a radially increasing magnetic field, as well as reduced fringe field and requires less power for a given field intensity. The subject invention comprises a pair of spaced, opposed magnetic poles which further comprise a pair of pole roots, each having a pole tip attached to its center. The pole tips define the gap between the magnetic poles and at least a portion of each pole tip is separated from its associated pole root. The separation begins at a predetermined distance from the center of the pole root and increases with increasing radial distance while being constant with azimuth within that portion. Magnets in accordance with the subject invention have been found to be particularly advantageous for use in large isochronous cyclotrons.
Free Magnetic Energy in Solar Active Regions above the Minimum-Energy Relaxed State
S. Regnier; E. R. Priest
2008-05-12
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.
Bioinspired Design : : Magnetic Freeze Casting
Porter, Michael Martin
2014-01-01
30 CHAPTER 3: FREEZE CASTING: A94 CHAPTER 5: MAGNETIC FREEZE CASTING INSPIRED BY98 5.2.1. Magnetic freeze casting
Electromagnetic acceleration of permanent magnets
Dolya, S N
2015-01-01
We consider the acceleration of the permanent magnets, consisting of neodymium iron boron by means of the running magnetic field gradient. It is shown that the specific magnetic moment per nucleon in neodymium iron boron is determined by the remained magnetization of the substance. The maximum accessable gradient of the magnetic field accelerating the permanent magnets is determined by the coercive force thirty kilogauss. For the neodymium iron boron magnets this gradient is equal to twenty kilogauss divided by one centimeter. The finite velocity of the magnets six kilometers per second, the length of acceleration is six hundred thirty-seven meters.
Lensless Imaging of Magnetic Nanostructures
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Print Magnetism is useful for many devices and techniques, from electric motors and computer hard drives to magnetic resonance imaging used in medicine. By studying...
QUENCHES IN LARGE SUPERCONDUCTING MAGNETS
Eberhard, P.H.
2010-01-01
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...
Acceptors as Values Functional Programming in Classical Linear Logic
Reddy, Uday S.
Acceptors as Values Functional Programming in Classical Linear this paper, we consider the application of classical linear logic to functional programming. T* *he negative" operator of linear logic gives rise to nondeter* *ministic values. We define a typed functional language
Is there a use for linear logic? Philip Wadler
Wadler, Philip
Is there a use for linear logic Past attempts to apply Girard's linear logicihavemplemented Wadler's system [Wa* *k90 ].) either had, Wadler), but not both. Thisguage that corresponds closely t* *o linear logic; it is a paper defines
AN OPTIMIZED SUPERFERRIC WIGGLER DESIGN FOR THE INTERNATIONAL LINEAR COLLIDER
AN OPTIMIZED SUPERFERRIC WIGGLER DESIGN FOR THE INTERNATIONAL LINEAR COLLIDER DAMPING RINGS Urban ALL RIGHTS RESERVED #12;AN OPTIMIZED SUPERFERRIC WIGGLER DESIGN FOR THE INTERNATIONAL LINEAR Linear Collider (ILC) damping rings. Results from optimizations of the parameters of this wiggler
AN OPTIMIZED SUPERFERRIC WIGGLER DESIGN FOR THE INTERNATIONAL LINEAR COLLIDER
AN OPTIMIZED SUPERFERRIC WIGGLER DESIGN FOR THE INTERNATIONAL LINEAR COLLIDER DAMPING RINGS Urban ALL RIGHTS RESERVED #12; AN OPTIMIZED SUPERFERRIC WIGGLER DESIGN FOR THE INTERNATIONAL LINEAR Linear Collider (ILC) damping rings. Results from optimizations of the parameters of this wiggler
Linear Cellular Automata and Fischer Automata Klaus Sutner
Sutner, Klaus
Linear Cellular Automata and Fischer Automata Klaus Sutner Carnegie Mellon University Pittsburgh finite state machines associated with linear cellular automata. In particular, we construct a class of binary linear cellular automata whose corresponding mini- mal automata exhibit full exponential blow
Computing nonlinear force free coronal magnetic fields
T. Wiegelmann; T. Neukirch
2008-01-21
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.
Jeremy S. Heyl; Lars Hernquist
1996-08-25
We calculate the reaction cross-sections for the fusion of hydrogen and deuterium in strong magnetic fields as are believed to exist in the atmospheres of neutron stars. We find that in the presence of a strong magnetic field ($B \\gsim 10^{12}$G), the reaction rates are many orders of magnitude higher than in the unmagnetized case. The fusion of both protons and deuterons are important over a neutron star's lifetime for ultrastrong magnetic fields ($B \\sim 10^{16}$G). The enhancement may have dramatic effects on thermonuclear runaways and bursts on the surfaces of neutron stars.
Bonanos, Peter (East Brunswick, NJ)
1983-01-01
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.
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Malik, V.; Goodwill, J.; Mallapragada, S.; Prozorov, T.; Prozorov, R.
2014-11-13
The rate of heating of a water-based colloid of uniformly sized 15 nm magnetic nanoparticles by high-amplitude and high-frequency ac magnetic field induced by the resonating LC circuit (nanoTherics Magnetherm) was measured. The results are analyzed in terms of specific energy absorption rate (SAR). Fitting field amplitude and frequency dependences of SAR to the linear response theory, magnetic moment per particles was extracted. The value of magnetic moment was independently evaluated from dc magnetization measurements (Quantum Design MPMS) of a frozen colloid by fitting field-dependent magnetization to Langevin function. The two methods produced similar results, which are compared to themore »theoretical expectation for this particle size. Additionally, analysis of SAR curves yielded effective relaxation time.« less
Malik, V.; Goodwill, J.; Mallapragada, S.; Prozorov, T.; Prozorov, R.
2014-11-13
The rate of heating of a water-based colloid of uniformly sized 15 nm magnetic nanoparticles by high-amplitude and high-frequency ac magnetic field induced by the resonating LC circuit (nanoTherics Magnetherm) was measured. The results are analyzed in terms of specific energy absorption rate (SAR). Fitting field amplitude and frequency dependences of SAR to the linear response theory, magnetic moment per particles was extracted. The value of magnetic moment was independently evaluated from dc magnetization measurements (Quantum Design MPMS) of a frozen colloid by fitting field-dependent magnetization to Langevin function. The two methods produced similar results, which are compared to the theoretical expectation for this particle size. Additionally, analysis of SAR curves yielded effective relaxation time.
Magnetization reversal assisted by half antivortex states in nanostructured circular cobalt disks
Lara, A.; Aliev, F. G.; Dobrovolskiy, O. V.; Prieto, J. L.; Huth, M.
2014-11-03
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.
Electronic and magnetic properties of Mo doped graphene; full potential approach
Thakur, Jyoti Kashyap, Manish K.; Singh, Mukhtiyar; Saini, Hardev S.
2015-05-15
The electronic and magnetic properties of Pristine and Mo doped Graphene have been calculated using WIEN2k implementation of full potential linearized augmented plane wave (FPLAPW) method based on Density Functional Theory (DFT). The exchange and correlation (XC) effects were taken into account by generalized gradient approximation (GGA). The calculated results show that Mo doping creates magnetism in Graphene by shifting the energy levels at E{sub F} and opens up a channel for Graphene to be used in real nanoscale device applications. The unpaired d-electrons of Mo atom are responsible for induced magnetism in Graphene. Magnetic ordering created in Graphene in this way makes it suitable for recording media, magnetic sensors, magnetic inks and spintronic devices.
Linear theory of microwave instability in electron storage rings...
Office of Scientific and Technical Information (OSTI)
Linear theory of microwave instability in electron storage rings Citation Details In-Document Search Title: Linear theory of microwave instability in electron storage rings...
Updates to the International Linear Collider Damping Rings Baseline...
Office of Scientific and Technical Information (OSTI)
Updates to the International Linear Collider Damping Rings Baseline Design Citation Details In-Document Search Title: Updates to the International Linear Collider Damping Rings...
Two linear slot nozzle virtual impactors for concentration of bioaerosols
Haglund, John Steven
2005-02-17
Two experimental configurations of linear slot nozzle virtual impactors were constructed and experimentally investigated for use as bioaerosol concentrators. In one configuration, the Linear Slot Virtual Impactor (LSVI), ...
2010 Annual Planning Summary for Stanford Linear Accelerator...
0 Annual Planning Summary for Stanford Linear Accelerator Center Site Office (SLAC) 2010 Annual Planning Summary for Stanford Linear Accelerator Center Site Office (SLAC) Annual...
Linear Concentrator System Basics for Concentrating Solar Power...
Office of Environmental Management (EM)
Linear Concentrator System Basics for Concentrating Solar Power Linear Concentrator System Basics for Concentrating Solar Power August 20, 2013 - 4:45pm Addthis Photo of numerous...
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
Anisotropy of magnetic emulsions induced by magnetic and electric fields
Yury I. Dikansky; Alexander N. Tyatyushkin; Arthur R. Zakinyan
2011-09-10
The anisotropy of magnetic emulsions induced by simultaneously acting electric and magnetic fields is theoretically and experimentally investigated. Due to the anisotropy, the electric conductivity and magnetic permeability of a magnetic emulsion are no longer scalar coefficients, but are tensors. The electric conductivity and magnetic permeability tensors of sufficiently diluted emulsions in sufficiently weak electric and magnetic fields are found as functions of the electric and magnetic intensity vectors. The theoretically predicted induced anisotropy was verified experimentally. The experimental data are analyzed and compared with theoretical predictions. The results of the analysis and comparison are discussed.
Modular tokamak magnetic system
Yang, Tien-Fang (Wayland, MA)
1988-01-01
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-
2004-01-01
(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 ...
Meyer, R.E.
1993-03-09
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.
Magnetic Catalysis in Graphene
Christopher Winterowd; Carleton DeTar; Savvas Zafeiropoulos
2015-09-22
One of the most important developments in condensed matter physics in recent years has been the discovery and characterization of graphene. A two-dimensional layer of Carbon arranged in a hexagonal lattice, graphene exhibits many interesting electronic properties, most notably that the low energy excitations behave as massless Dirac fermions. These excitations interact strongly via the Coulomb interaction and thus non-perturbative methods are necessary. Using methods borrowed from lattice QCD, we study the graphene effective theory in the presence of an external magnetic field. Graphene, along with other $(2+1)$-dimensional field theories, has been predicted to undergo spontaneous breaking of flavor symmetry including the formation of a gap as a result of the external magnetic field. This phenomenon is known as magnetic catalysis. Our study investigates magnetic catalysis using a fully non-perturbative approach.
Magnetic Catalysis in Graphene
Winterowd, Christopher; Zafeiropoulos, Savvas
2015-01-01
One of the most important developments in condensed matter physics in recent years has been the discovery and characterization of graphene. A two-dimensional layer of Carbon arranged in a hexagonal lattice, graphene exhibits many interesting electronic properties, most notably that the low energy excitations behave as massless Dirac fermions. These excitations interact strongly via the Coulomb interaction and thus non-perturbative methods are necessary. Using methods borrowed from lattice QCD, we study the graphene effective theory in the presence of an external magnetic field. Graphene, along with other $(2+1)$-dimensional field theories, has been predicted to undergo spontaneous breaking of flavor symmetry including the formation of a gap as a result of the external magnetic field. This phenomenon is known as magnetic catalysis. Our study investigates magnetic catalysis using a fully non-perturbative approach.
Meyer, Ross E. (Los Alamos, NM)
1993-01-01
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.
1D Regression ... estimates of the linear regression coefficients are relevant to the linear
Olive, David
Chapter 12 1D Regression ... estimates of the linear regression coefficients are relevant and look for a functional form for g(·). Brillinger (1983, p. 98) Regression is the study. The scalar Y is a random variable and x is a random vector. A special case of regression is multiple linear
1D Regression ... estimates of the linear regression coefficients are relevant to the linear
Olive, David
Chapter 15 1D Regression ... estimates of the linear regression coefficients are relevant and look for a functional form for g(·). Brillinger (1983, p. 98) Regression is the study. The scalar Y is a random variable and x is a random vector. A special case of regression is multiple linear
Linear and NonLinear Estimation Methods Applied to the Hemodynamic model
Schaal, Stefan
Linear and NonLinear Estimation Methods Applied to the Hemodynamic model Evangelos A. Theodorou s that controls the blood inflow. The total balloon model can be defined by the 4 differential equations the hemodynamic process of the balloon model. These equations consist of a set of deterministic highly non
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 and Ulrike Meier Yang2,, 1Department of Applied Mathematics, University of Waterloo, Waterloo, Ont., Canada N2L 3G1 2Center for Applied Scientific Computing, Lawrence Livermore National Laboratory, P.O. Box
Best unbiased ensemble linearization and the quasi-linear Kalman ensemble generator
Cirpka, Olaf Arie
Best unbiased ensemble linearization and the quasi-linear Kalman ensemble generator W. Nowak1 in hydrogeology, e.g., for geostatistical inversion or generating conditional realizations. The respectiveKF, the new method is called the Kalman ensemble generator (KEG). The new context of best unbiased ensemble
Linear Stability Analysis of Dynamical Quadratic Gravity
Dimitry Ayzenberg; Kent Yagi; Nicolas Yunes
2014-03-18
We perform a linear stability analysis of dynamical, quadratic gravity in the high-frequency, geometric optics approximation. This analysis is based on a study of gravitational and scalar modes propagating on spherically-symmetric and axially-symmetric, vacuum solutions of the theory. We find dispersion relations that do no lead to exponential growth of the propagating modes, suggesting the theory is linearly stable on these backgrounds. The modes are found to propagate at subluminal and superluminal speeds, depending on the propagating modes' direction relative to the background geometry, just as in dynamical Chern-Simons gravity.
Linear and angular retroreflecting interferometric alignment target
Maxey, L. Curtis (Powell, TN)
2001-01-01
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.
Linear Transformation Method for Multinuclide Decay Calculation
Ding Yuan
2010-12-29
A linear transformation method for generic multinuclide decay calculations is presented together with its properties and implications. The method takes advantage of the linear form of the decay solution N(t) = F(t)N{sub 0}, where N(t) is a column vector that represents the numbers of atoms of the radioactive nuclides in the decay chain, N{sub 0} is the initial value vector of N(t), and F(t) is a lower triangular matrix whose time-dependent elements are independent of the initial values of the system.
On the Electrical and Magnetic Properties of some Indian Spices
Samson. K. Baby; T. E. Girish
2010-12-11
We have made experimental measurements of electrical conductivity, pH and relative magnetic susceptibility of the aqueous solutions of 24 indian spices. The measured values of electrical conductance of these spices are found to be linearly related to their ash content and bulk calorific values reported in literature. The physiological relevance of the pH and diamagnetic susceptibility of spices when consumed as food or medicine will be also discussed.
Savici, Andrei T [ORNL; Granroth, Garrett E [ORNL; Broholm, Collin L [ORNL; Bird, Mark D [ORNL; Lee, Young S [ORNL
2010-01-01
ZEEMANS, a new instrument proposed for the Spallation Neutron Source (SNS) at Oak Ridge, will provide highest available magnetic elds for neutron scattering experiments. The unique capabilities of the magnet, large size and required connection to utilities demand a versatile instrument, able of performing diraction (powder and single crystal), SANS, re ectometry, and inelastic spectrometry, with minimal modications between congurations. In this paper we present preliminary design features for ZEEMANS. Monte Carlo simulations and analytical calculations were used to study its expected performance.
Nance, Thomas A. (Aiken, SC)
2009-08-18
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.
1983-12-29
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.
Linear and non-linear forced response of a conical, ducted, laminar premixed flame
Karimi, Nader; Brear, Michael J.; Jin, Seong-Ho; Monty, Jason P. [Department of Mechanical Engineering, University of Melbourne, Parkville, 3010 Vic. (Australia)
2009-11-15
This paper presents an experimental study on the dynamics of a ducted, conical, laminar premixed flame subjected to acoustic excitation of varying amplitudes. The flame transfer function is measured over a range of forcing frequencies and equivalence ratios. In keeping with previous works, the measured flame transfer function is in good agreement with that predicted by linear kinematic theory at low amplitudes of acoustic velocity excitation. However, a systematic departure from linear behaviour is observed as the amplitude of the velocity forcing upstream of the flame increases. This non-linearity is mostly in the phase of the transfer function and manifests itself as a roughly constant phase at high forcing amplitude. Nonetheless, as predicted by non-linear kinematic arguments, the response always remains close to linear at low forcing frequencies, regardless of the forcing amplitude. The origin of this phase behaviour is then sought through optical data post-processing. (author)
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)
2013-09-15
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)
2000-12-19
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.
Office of Energy Efficiency and Renewable Energy (EERE)
Non-Linear Seismic Soil Structure Interaction (SSI) Method for Developing Non-Linear Seismic SSI Analysis Techniques Justin Coleman, P.E. October 25th, 2011
Telescoping magnetic ball bar test gage
Bryan, J.B.
1982-03-15
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.; Harvey, J. W.; Pietarila, A. E-mail: jharvey@nso.edu
2013-03-10
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.
Freely oriented portable superconducting magnet
Schmierer, Eric N. (Los Alamos, NM); Prenger, F. Coyne (Los Alamos, NM); Hill, Dallas D. (Los Alamos, NM)
2010-01-12
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.
Interface characterization of epitaxial Fe/MgO/Fe magnetic tunnel junctions
Wang, Shouguo; Ward, R. C. C.; Zhang, Xiaoguang; Kohn, A.; Ma, Q. L.; Zhang, J.; Liu, H. F.; Han, Prof. X. F.
2012-01-01
Following predictions by first-principles theory of huge tunnel magnetoresistance (TMR) effect in epitaxial Fe/MgO/Fe magnetic tunnel junctions (MTJs), measured magnetoresistance (MR) ratio about 200% at room temperature (RT) have been reported in MgO-based epitaxial MTJs. Recently, MR ratio of about 600% has been reported at RT in MgO-based amorphous MTJs with core structure of CoFeB/MgO/CoFeB grown by magnetron sputtering with amorphous CoFeB layers. The sputtered CoFeB/MgO/CoFeB MTJs shows a great potential application in spintronic devices. Although epitaxial structure will probably not be used in devices, it remains an excellent model system to compare theoretical calculations with experimental results and to enhance our understanding of the spin dependent tunneling. Both theoretical calculations and experimental results clearly indicate that the interfacial structure plays a crucial role on coherent tunneling across single crystalMgO barrier, especially in epitaxial MgO-based MTJs grown by molecular beam epitaxy (MBE). Surface X-ray diffraction, Auger electron spectroscopy, X-ray absorption spectra, and X-ray magnetic circular dichroism have been used for interface characterization. However, no consistent viewpoint has been reached, and this is still an open issue. In this article, recent studies on the interface characterization in MgO-based epitaxial MTJs will be introduced, with a focus on research by X-ray photoelectron spectroscopy, high resolution transmission electron microscopy, and spin dependent tunneling spectroscopy.
Modification of {Delta}{sup Prime} by magnetic feedback and kinetic effects
Liu Yueqiang; Hastie, R. J.; Hender, T. C. [Euratom/CCFE Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom)
2012-09-15
Two possible ways of modifying the linear tearing mode index, by active magnetic feedback and by drift kinetic effects of deeply trapped particles, are analytically investigated. Magnetic feedback schemes, studied in this work, are found generally stabilizing for {Delta}{sup Prime }. The drift kinetic effects from both thermal particles and hot ions tend to reduce the power of the large solution from the outer region. This generally leads to a destabilization of {Delta} Prime for the toroidal analytic equilibria considered here.
Deconfinement to quark matter in neutron stars - The influence of strong magnetic fields
Dexheimer, V.; Negreiros, R.; Schramm, S.; Hempel, M.
2013-03-25
We use an extended version of the hadronic SU(3) non-linear realization of the sigma model that also includes quarks to study hybrid stars. Within this approach, the degrees of freedom change naturally as the temperature/density increases. Different prescriptions of charge neutrality, local and global, are tested and the influence of strong magnetic fields and the anomalous magnetic moment on the particle population is discussed.
Architecture of an Automatic Tuned Linear Algebra
Cuenca, Javier
Algebra Routine of the library we want to build SOLAR_manager Manages the information and code of SOLAR .... SPt c,z Architecture of a Self-Optimised Linear Algebra Routine (SOLAR) Installation_information n1 Current_network_availability % net1-1 ...%net1-p ... % netP-1 ..%netp-p SOLAR_manager Optimum_AP AP0
Robotic Motion The linear algebra of Canadarm
Murty, Ram
Robotic Motion The linear algebra of Canadarm #12;The robot arm simulation The movements of the robotic arm can be described using orthogonal matrices. #12;Six degrees of freedom The first segment the robotic arm to the position (x,y), we need to rotate the first arm by an angle and the second arm
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
Linear Algebra MATH 110 : 2006-07
Wehlau, David
MATH 110 Linear Algebra MATH 110 : 2006-07 Home Policies Fall Winter WebCT Instructor: G.G. Smith: MATH 111, 112 Lectures: (slot 014) Tuesday, 11:30-12:30 in 210 Walter Light Hall Wednesday, 13:30-14:30 in 210 Walter Light Hall Friday, 12:30-13:30 in 210 Walter Light Hall Tutorials: Wednesday, 8
Aggregate Functions, Conservative Extension, and Linear Orders
Libkin, Leonid
Aggregate Functions, Conservative Extension, and Linear Orders Leonid Libkin Limsoon Wong Summary Practical database query languages are usually equipped with some aggregate functions. For example, \\ nd mean of column" can be expressed in SQL. However, the manner in which aggregate functions were
A microcomputer-controlled linear heater
Schuck, V.; Rahimi, S. )
1991-10-01
In this note the circuits and principles of operation of a relatively simple and inexpensive linear temperature ramp generator are described. The upper-temperature limit and the heating rate are controlled by an Apple II microcomputer. The temperature versus time is displayed on the screen and may be plotted by an {ital x}-{ital y} plotter.
A Compositional Framework for Passive Linear Networks
John C. Baez; Brendan Fong
2015-07-24
Passive linear networks are used in a wide variety of engineering applications, but the best studied are electrical circuits made of resistors, inductors and capacitors. We describe a category where a morphism is a circuit of this sort with marked input and output terminals. In this category, composition describes the process of attaching the outputs of one circuit to the inputs of another. We construct a functor, dubbed the "black box functor", that takes a circuit, forgets its internal structure, and remembers only its external behavior. Two circuits have the same external behavior if and only if they impose same relation between currents and potentials at their terminals. The space of these currents and potentials naturally has the structure of a symplectic vector space, and the relation imposed by a circuit is a Lagrangian linear relation. Thus, the black box functor goes from our category of circuits to the category of symplectic vector spaces and Lagrangian linear relations. We prove that this functor is a symmetric monoidal dagger functor between dagger compact categories. We assume the reader has some familiarity with category theory, but none with circuit theory or symplectic linear algebra.
Automatic tuning for linearly tunable filter
Huang, Sung-Ling
2004-09-30
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-quadratic fractional Gaussian control
Duncan, Tyrone E.; Pasik-Duncan, Bozenna
2013-01-01
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...
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
August, 2010 Non Linear Contracting and
matter considerably for the ...nal price setting by retailers, for competi- tion analysis and market retailers to have some endogenous buyer power coming from the horizontal competition of manufacturers. Our10-189 August, 2010 Non Linear Contracting and Endogenous Buyer Power between Manufacturers
Performance Bounds for Constrained Linear Stochastic Control
Engineering Department Stanford University Workshop on Optimization and Control with Applications, Harbin · numerical examples Workshop on Optimization and Control with Applications, Harbin, June 9 2009 1 #12;Linear is zero mean IID process noise, E wtwT t = W · state feedback control policy: ut = (xt), t = 0, 1
IMPROVED DENSITY ESTIMATORS FOR INVERTIBLE LINEAR PROCESSES
Wefelmeyer, Wolfgang
IMPROVED DENSITY ESTIMATORS FOR INVERTIBLE LINEAR PROCESSES Anton Schick Department of Mathematical-statistic with kernel of the form K(x) = k(x - ay)k(y) dy. Schick and Wefelmeyer (2004b, 2007a) prove functional central and Schick (2007) obtain similar results for derivatives of convolutions. Schick and Wefelmeyer (2008b
Physics Case for the International Linear Collider
Keisuke Fujii; Christophe Grojean; Michael E. Peskin; Tim Barklow; Yuanning Gao; Shinya Kanemura; Hyungdo Kim; Jenny List; Mihoko Nojiri; Maxim Perelstein; Roman Poeschl; Juergen Reuter; Frank Simon; Tomohiko Tanabe; Jaehoon Yu; James D. Wells; Hitoshi Murayama; Hitoshi Yamamoto
2015-06-26
We summarize the physics case for the International Linear Collider (ILC). We review the key motivations for the ILC presented in the literature, updating the projected measurement uncertainties for the ILC experiments in accord with the expected schedule of operation of the accelerator and the results of the most recent simulation studies.
Physics Case for the International Linear Collider
Fujii, Keisuke; Peskin, Michael E; Barklow, Tim; Gao, Yuanning; Kanemura, Shinya; Kim, Hyungdo; List, Jenny; Nojiri, Mihoko; Perelstein, Maxim; Poeschl, Roman; Reuter, Juergen; Simon, Frank; Tanabe, Tomohiko; Yu, Jaehoon; Wells, James D; Murayama, Hitoshi; Yamamoto, Hitoshi
2015-01-01
We summarize the physics case for the International Linear Collider (ILC). We review the key motivations for the ILC presented in the literature, updating the projected measurement uncertainties for the ILC experiments in accord with the expected schedule of operation of the accelerator and the results of the most recent simulation studies.
NON-LINEAR COMPLEXITY OF THE NAORREINGOLD
Banks, William D.
Griffin2 , Daniel Lieman3 , Igor E. Shparlinski4 1 Department of Mathematics, University of Missouri is an extension of the lower bound on the linear complexity of this function that has been obtained by F. Griffin-dimensional vector a = (a1, . . . , an) (IF l )n one can define the function fa(X) = ga x1 1 ...axn n IFp, where X
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 rotary optical delay lines Maksim Skorobogatiy*
Skorobogatiy, Maksim
Linear rotary optical delay lines Maksim Skorobogatiy* Department of Engineering Physics, École of analytical and semi-analytical solutions for the design of high-speed rotary optical delay lines that use of optical delay. Finally, two prototypes of rotary delay lines were fabricated using CNC machining
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
Curso de lgebra Linear Fundamentos e Aplicaes
Cabral, Marco
+ v u0 v u + v u0 v u + v u 0 v u + v Marco Cabral Paulo Goldfeld #12;ii #12;Curso de Ãlgebra Linear Fundamentos e AplicaÃ§Ãµes Segunda EdiÃ§Ã£o Setembro de 2012 Marco A. P. Cabral hh sndin niversityD ie rofF sw
MA265 Linear Algebra — Sample Exam 1
page 1. Purdue University. MA265 Linear Algebra — Sample Exam 1. Date: February 20, 2015 Duration: 50 ... 1. Determine A such that (let-(A). 7 .110 [p. 1100 O r. In. )1 A n 1. \\\\\\\\l_ he zlxrs M. \\11. '01 .... Rep'mr'ata. 1 F'ncl '3“ m muVVnN
Testing Multivariate Linear Functions: Overcoming the Generator Bottleneck
Ergun, Funda
Testing Multivariate Linear Functions: Overcoming the Generator Bottleneck Funda ErgÂ¨un \\Lambda present efficient methods for selfÂtesting multivariate linear functions. We then apply these methods the problem of selfÂtesting multivariate linear functions, i.e., given a multivariate linear function f
Acceptors as Values Functional Programming in Classical Linear Logic
Reddy, Uday S.
Acceptors as Values Functional Programming in Classical Linear Logic (Technical Summary) Uday S the application of classical linear logic to functional programming. The negative types of linear logic]. The only application of classical linear logic to functional programming has been by Filinski [10] who uses
Acceptors as Values Functional Programming in Classical Linear Logic
Reddy, Uday S.
Acceptors as Values Functional Programming in Classical Linear Logic (Technical Summary) Uday S the application of classical linear logic to functional programming. The negative types of linear logic linear logic to functional programming has been by Filinski [10] who uses negative types to model
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
MATH 532: Linear Algebra Chapter 3: Matrix Algebra
Fasshauer, Greg
MATH 532: Linear Algebra Chapter 3: Matrix Algebra Greg Fasshauer Department of Applied Mathematics;Introduction Linear algebra is an old subject fasshauer@iit.edu MATH 532 5 #12;Introduction Linear algebra]. fasshauer@iit.edu MATH 532 5 #12;Introduction Linear algebra is an old subject The origins are attributed
Relationship Between Solar Wind Speed and Coronal Magnetic Field Properties
Fujiki, Ken'ichi; Iju, Tomoya; Hakamada, Kazuyuki; Kojima, Masayoshi
2015-01-01
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...
Neutrino Propagation and Oscillations in a Strong Magnetic Field
Efrain J. Ferrer; Vivian de la Incera
2004-08-08
We review the results on neutrino propagation in neutral and charged media under strong magnetic fields $M_{W}^{2}\\gg B\\gg m_{e}^{2}$. It is shown that the neutrino energy density gets a magnetic contribution in both charged and neutral media, which is linear in the magnetic field, of first order in $G_{F}$, and independent of the charge density. This new term enters as a correction to the neutrino kinetic energy and produces an anisotropic contribution to the neutrino index of refraction. As a consequence, in a neutral medium a highly anisotropic resonant level-crossing condition takes place for the oscillation between electron-neutrinos and the other neutrino species. Possible cosmological applications are presented.
A magnetic thermal switch for heat management at the nanoscale
Riccardo Bosisio; Stefano Valentini; Francesco Mazza; Giuliano Benenti; Rosario Fazio; Vittorio Giovannetti; Fabio Taddei
2015-05-15
In a multi-terminal setup, when time-reversal symmetry is broken by a magnetic field, the heat flows can be managed by designing a device with programmable Boolean behavior. We show that such device can be used to implement operations like on/off switching, reversal, selected splitting and swap of the heat currents. For each feature, the switching from one working condition to the other is obtained by inverting the magnetic field. This offers interesting opportunities of conceiving a programmable setup, whose operation is controlled by an external parameter (the magnetic field) without need to alter voltage and thermal biases applied to the system. Our results, generic within the framework of linear response, are illustrated by means of a three-terminal electronic interferometer model.
Integer Algorithms to Solver Diophantine Linear Equations and Systems
Florentin Smarandache
2007-11-28
The present work includes some of the author's original researches on integer solutions of Diophantine liner equations and systems. The notion of "general integer solution" of a Diophantine linear equation with two unknowns is extended to Diophantine linear equations with $n$ unknowns and then to Diophantine linear systems. The proprieties of the general integer solution are determined (both for a Diophantine linear equation and for a Diophantine linear system). Seven original integer algorithms (two for Diophantine linear equations, and five for Diophantine linear systems) are exposed. The algorithms are strictly proved and an example for each of them is given. These algorithms can be easily implemented on the computer.
Design and Control of a Floating Wave-Energy Converter Utilizing a Permanent Magnet Linear Generator
Tom, Nathan Michael
2013-01-01
Force . . . . . . . . . . . . . . . . . . . .GeneratorGenerator Dry Bench Test . . . . . . . . .4.5.7 Generator Power
Non-Linear Magnetic Ringing of Spin-Ordered Solid He-3
Hu, Chia-Ren; HAM, TE.
1981-01-01
be well fitted by the formula [(uL + I)0 + [ ( cuL IIO) +4cuL I)a cos Q] I where ~L ?= yH is the Larmor frequency, and the + sign indicates that there are two resonance branches at any given applied field H. Furthermore, they have shown... the integral in Eq. (17) in terms of a Jacobian elliptical integral 2.2 2.0 1.8 1.6 sing(=d, ) = ?X sn(X+rlnt) m = (X-IX+)', (19) which also gives the time dependence of dq~ =1 ?d,', sg =sp S1n H ?d, and s =sp ?d Evaluating (B,s?)~+(B,sy)~ and ((l...
Design and Control of a Floating Wave-Energy Converter Utilizing a Permanent Magnet Linear Generator
Tom, Nathan Michael
2013-01-01
electrical generator technology for wave energy converters,”seen, clean technologies, such as ocean wave energy, presentwave energy point absorber,” Proceedings of the IFAC Conference on Control Methodologies and Technology
Design and Control of a Floating Wave-Energy Converter Utilizing a Permanent Magnet Linear Generator
Tom, Nathan Michael
2013-01-01
Conference on Electric Machines and Drives (IEMDC-03), JuneConference on Electric Machines & Drives (IEMDC-07), 2,Vernier hybrid machines,” IEEE Proceedings Electric Power
Design and Control of a Floating Wave-Energy Converter Utilizing a Permanent Magnet Linear Generator
Tom, Nathan Michael
2013-01-01
electrical generator technology for wave energy converters,”wave energy point absorber,” Proceedings of the IFAC Conference on Control Methodologies and Technologyseen, clean technologies, such as ocean wave energy, present
Design and Control of a Floating Wave-Energy Converter Utilizing a Permanent Magnet Linear Generator
Tom, Nathan Michael
2013-01-01
control of resonant wave energy devices,” Phil. Trans. R.control of deep water wave energy devices using an activecapture of a wave energy device by inertia adjustment,”
Sheared-flow induced confinement transition in a linear magnetized plasma W. W. Heidbrink,1
Heidbrink, William W.
Department of Physics and Astronomy, University of California, Irvine, California 92697, USA 2 Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA (Received 22 September (Ln ¼ jr ln njÀ1 $ 2 cm) and shearing rate (c $ 300 kHz). Edge turbulence and cross-field transport
Simulation of non-linear rf losses derived from characteristic Nb topography
Reece, Charles E. [JLAB; Xu, Chen; Kelley, Michael [W& M. JLAB
2013-09-01
A simplified model has been developed to simulate non-linear RF losses on Nb surfaces exclusively due to topographical enhancement of surface magnetic fields. If local sharp edges are small enough, at locations where local surface fields exceed Hc, small volumes of material may become normal conducting without thermal leading to quench. These small volumes of normal material yield increases in the effective surface resistance of the Nb. Using topographic data from typical BCP?d and EP?d fine grain niobium surfaces, we have simulated field-dependent losses and found that when extrapolated to resulting cavity performance, these losses correspond well to characteristic BCP/EP high field Q0 performance differences for fine grain Nb. We describe the structure of the model, its limitations, and the effects of this type of non-linear loss contribution on SRF cavities.
Baumgaertel, J A; Mikkelsen, D R
2012-01-01
One metric for comparing confinement properties of different magnetic fusion energy configurations is the linear critical gradient of drift wave modes. The critical gradient scale length determines the ratio of the core to pedestal temperature when a plasma is limited to marginal stability in the plasma core. The gyrokinetic turbulence code GS2 was used to calculate critical temperature gradients for the linear, collisionless ion temperature gradient (ITG) mode in the National Compact Stellarator Experiment (NCSX) and a prototypical shaped tokamak, based on the profiles of a JET H-mode shot and the stronger shaping of ARIES-AT. While a concern was that the narrow cross section of NCSX at some toroidal locations would result in steep gradients that drive instabilities more easily, it is found that other stabilizing effects of the stellarator configuration offset this so that the normalized critical gradients for NCSX are competitive with or even better than for the tokamak. For the adiabatic ITG mode, NCSX and...
Solar receiver heliostat reflector having a linear drive and position information system
Horton, Richard H. (Schenectady, NY)
1980-01-01
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
2008-05-23
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
2014-02-24
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.
Barclay, J.A.; Steyert, W.A.
1981-01-27
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)
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.
2014-02-28
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
DuBois, A. M.; Arnold, I.; Thomas, E. Jr.; Tejero, E.; Amatucci, W. E.
2013-04-15
The Auburn Linear EXperiment for Instability Studies (ALEXIS) is a laboratory plasma physics experiment used to study spatially inhomogeneous flows in a magnetized cylindrical plasma column that are driven by crossed electric (E) and magnetic (B) fields. ALEXIS was recently upgraded to include a small, secondary plasma source for a new dual source, interpenetrating plasma experiment. Using two plasma sources allows for highly localized electric fields to be made at the boundary of the two plasmas, inducing strong E Multiplication-Sign B velocity shear in the plasma, which can give rise to a regime of instabilities that have not previously been studied in ALEXIS. The dual plasma configuration makes it possible to have independent control over the velocity shear and the density gradient. This paper discusses the recent addition of the secondary plasma source to ALEXIS, as well as the plasma diagnostics used to measure electric fields and electron densities.
Hot Jupiters and stellar magnetic activity
A. F. Lanza
2008-05-20
Recent observations suggest that stellar magnetic activity may be influenced by the presence of a close-by giant planet. Specifically, chromospheric hot spots rotating in phase with the planet orbital motion have been observed during some seasons in a few stars harbouring hot Jupiters. The spot leads the subplanetary point by a typical amount of about 60-70 degrees, with the extreme case of upsilon And where the angle is about 170 degrees. The interaction between the star and the planet is described considering the reconnection between the stellar coronal field and the magnetic field of the planet. Reconnection events produce energetic particles that moving along magnetic field lines impact onto the stellar chromosphere giving rise to a localized hot spot. A simple magnetohydrostatic model is introduced to describe the coronal magnetic field of the star connecting its surface to the orbiting planet. The field is assumed to be axisymmetric around the rotation axis of the star and its configuration is more general than a linear force-free field. With a suitable choice of the free parameters, the model can explain the phase differences between the hot spots and the planets observed in HD 179949, upsilon And, HD 189733, and tau Bootis, as well as their visibility modulation on the orbital period and seasonal time scales. The possible presence of cool spots associated with the planets in tau Boo and HD 192263 cannot be explained by the present model. However, we speculate about the possibility that reconnection events in the corona may influence subphotospheric dynamo action in those stars producing localized photospheric (and chromospheric) activity migrating in phase with their planets.
Measuring non-linear functionals of quantum harmonic oscillator states
K. L. Pregnell
2005-11-01
Using only linear interactions and a local parity measurement we show how entanglement can be detected between two harmonic oscillators. The scheme generalizes to measure both linear and non-linear functionals of an arbitrary oscillator state. This leads to many applications including purity tests, eigenvalue estimation, entropy and distance measures - all without the need for non-linear interactions or complete state reconstruction. Remarkably, experimental realization of the proposed scheme is already within the reach of current technology with linear optics.
E. Florido; E. Battaner
1997-10-17
In paper I, we obtained an equation for the evolution of density inhomogeneities in a radiation dominated universe when they are affected by magnetic fields. In this second paper we apply this equation to the case in which the subjacent magnetic configuration is a flux tube. For scales of the order of 1 Mpc or less the differential equation is elliptical. To solve it, we have used the numerical method based on "Simultaneous Over Relaxation", SOR, with Chebyshev acceleration and we have treated the problem as a boundary value problem, which restricts the prediction ability of the integration. For large-scale flux tubes, much larger than 1 Mpc, the equation can be analytically integrated and no assumption about the final shape or magnitude of the inhomogeneity is required. In both cases we obtain an evolution which does not differ very much from linear in time. The inhomogeneity in the density becomes filamentary. Large scale structures ($\\ge$ 10 Mpc) are probably unaffected by damping, non-linear and amplification mechanisms after Equality, so that this model provides a tool to interpret the present observed large scale structure. Filaments are very frequently found in the large-scale structure in the Universe. It is suggested here that they could arise from primordial magnetic flux tubes, thus providing an alternative hypothesis for its interpretation; in particular we consider the case of the Coma-A1367 supercluster, where the magnetic field is known to be high.
Franceschetti, Massimo
Functions by Linear Coding Over Networks Rathinakumar Appuswamy, Member, IEEE, and Massimo Franceschetti and a receiver node demands an arbi- trary linear function of these messages. We formulate an algebraic test to determine whether an arbitrary network can compute linear functions using linear codes. We identify a class
Linear study of Rayleigh-Taylor instability in a diffusive quantum plasma
Momeni, Mahdi
2013-08-15
The linear Rayleigh-Taylor (RT) instability in an incompressible quantum plasma is investigated on the basis of quantum magnetohydrodynamic model. It is shown that the occurrence of RT instability depends on density-temperature inhomogeneity (characteristic lengths) on one hand, and the system layer size on the other. It is also observed that the combined effects of external magnetic field, diffusivity, and quantum pressure significantly modify the dispersion properties of system in both the parallel and perpendicular directions. For any case, the imaginary and real parts of dispersion relation are presented and the possibility and conditions for the instability growth rate are discussed.
Linear stability of magnetohydrodynamic flow in a square duct with thin conducting walls
Priede, J?nis; Bühler, Leo
2015-01-01
This study is concerned with numerical linear stability analysis of liquid metal flow in a square duct with thin electrically conducting walls subject to a uniform transverse magnetic field. We derive an asymptotic solution for the base flow which is valid not only for high but also moderate magnetic fields. This solution shows that for low wall conductance ratios $c\\ll1,$ an extremely strong magnetic field with the Hartmann number $Ha\\sim c^{-4}$ is required to attain the asymptotic flow regime considered in the previous studies. We use a vector stream function/vorticity formulation and a Chebyshev collocation method to solve the eigenvalue problem for three-dimensional small-amplitude perturbations in ducts with realistic wall conductance ratios $c=1,0.1,0.01$ and Hartmann numbers up to $10^{4}.$ As for similar flows, instability in a sufficiently strong magnetic field is found to occur in the side-wall jets with the characteristic thickness $\\delta\\sim Ha^{-1/2}.$ This results in the critical Reynolds numb...
The two-phase issue in the O(n) non-linear $?$-model: A Monte Carlo study
B. Alles; A. Buonanno; G. Cella
1996-08-01
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 nanoparticle temperature estimation
Weaver, John B.; Rauwerdink, Adam M.; Hansen, Eric W.
2009-05-15
The authors present a method of measuring the temperature of magnetic nanoparticles that can be adapted to provide in vivo temperature maps. Many of the minimally invasive therapies that promise to reduce health care costs and improve patient outcomes heat tissue to very specific temperatures to be effective. Measurements are required because physiological cooling, primarily blood flow, makes the temperature difficult to predict a priori. The ratio of the fifth and third harmonics of the magnetization generated by magnetic nanoparticles in a sinusoidal field is used to generate a calibration curve and to subsequently estimate the temperature. The calibration curve is obtained by varying the amplitude of the sinusoidal field. The temperature can then be estimated from any subsequent measurement of the ratio. The accuracy was 0.3 deg. K between 20 and 50 deg. C using the current apparatus and half-second measurements. The method is independent of nanoparticle concentration and nanoparticle size distribution.
Aized, D.; Schwall, R.E.
1999-06-22
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.
Towards a Future Linear Collider and The Linear Collider Studies at CERN
None
2011-10-06
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.
Asymmetric evolution of magnetic reconnection in collisionless accretion disk
Shirakawa, Keisuke Hoshino, Masahiro
2014-05-15
An evolution of a magnetic reconnection in a collisionless accretion disk is investigated using a 2.5 dimensional hybrid code simulation. In astrophysical disks, magnetorotational instability (MRI) is considered to play an important role by generating turbulence in the disk and contributes to an effective angular momentum transport through a turbulent viscosity. Magnetic reconnection, on the other hand, also plays an important role on the evolution of the disk through a dissipation of a magnetic field enhanced by a dynamo effect of MRI. In this study, we developed a hybrid code to calculate an evolution of a differentially rotating system. With this code, we first confirmed a linear growth of MRI. We also investigated a behavior of a particular structure of a current sheet, which would exist in the turbulence in the disk. From the calculation of the magnetic reconnection, we found an asymmetric structure in the out-of-plane magnetic field during the evolution of reconnection, which can be understood by a coupling of the Hall effect and the differential rotation. We also found a migration of X-point whose direction is determined only by an initial sign of J{sub 0}×?{sub 0}, where J{sub 0} is the initial current density in the neutral sheet and ?{sub 0} is the rotational vector of the background Keplerian rotation. Associated with the migration of X-point, we also found a significant enhancement of the perpendicular magnetic field compared to an ordinary MRI. MRI-Magnetic reconnection coupling and the resulting magnetic field enhancement can be an effective process to sustain a strong turbulence in the accretion disk and to a transport of angular momentum.
Wireless Magnetic Sensor Applications in Transportation Infrastructure
Sanchez, Rene Omar
2012-01-01
2.2 Wireless Magnetic Sensors Vehicle Detection2.3 Vehicle Re-Identification Using Wireless MagneticPerformance iv 6 Wireless Magnetic Sensor Applications for
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)
2012-10-15
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.
Martin, D A
2015-01-01
We study evolution equations and stationary homogeneous solutions for electric and magnetic field amplitudes in a ring cavity with flat mirrors. The cavity is filled with a positive or negative refraction index material with third order Kerr-like electric nonlinearities and also magnetic nonlinearities, which can be relevant in metamaterials. We consider the degree of freedom of polarization in the incident beam. It is found that considering a magnetic nonlinearity increases the variety of possible qualitatively different solutions. A classification of solutions is proposed in terms of the number of bifurcations. The analysis can be useful for the implementation of optical switching or memory storage using ring cavities with non linear materials.
Wu, J.; Park, J.; Kim, W.; Arenholz, E.; Liberati, M.; Scholl, A.; Wu, Y.; Hwang, C.; Qiu, Z.
2010-02-10
The exchange bias of epitaxially grown CoO/Fe/Ag(001) was investigated using X-ray Magnetic Circular Dichroism (XMCD) and X-ray Magnetic Linear Dichroism (XMLD) techniques. A direct XMLD measurement on the CoO layer during the Fe magnetization reversal shows that the CoO compensated spins are rotatable at thinner thickness and frozen, i.e. fixed in direction to the lattice, at larger thickness. By a quantitative determination of the rotatable and frozen CoO spins as a function of the CoO film thickness, we find the remarkable result that the exchange bias is well established before frozen spins are detectable in the CoO film, contrary to the common assumption that the majority of antiferromagnetic spins need to be frozen to generate the exchange bias. We further show that the rotatable/frozen CoO spins are uniformly distributed in the CoO film.
A direct measurement of rotatable and frozen CoO spins in exchange bias system of CoO/Fe/Ag(001)
Wu, J.; Park, J. S.; Kim, W.; Arenholz, E.; Liberati, M.; Scholl, A.; Wu, Y. Z.; Hwang, C.; Qiu, Z. Q.
2010-03-10
The exchange bias of epitaxially grown CoO/Fe/Ag(001) was investigated using x-ray magnetic circular dichroism and x-ray magnetic linear dichroism (XMLD) techniques. A direct XMLD measurement on the CoO layer during the Fe magnetization reversal shows that the CoO compensated spins are rotatable at thinner thickness and frozen at larger thickness. By a quantitative determination of the rotatable and frozen CoO spins as a function of the CoO film thickness, we find the remarkable result that the exchange bias is well established before frozen spins are detectable in the CoO film. We further show that the rotatable and frozen CoO spins are uniformly distributed in the CoO film.
Noise in phase-preserving linear amplifiers
Pandey, Shashank; Jiang, Zhang; Combes, Joshua; Caves, Carlton M.
2014-12-04
The purpose of a phase-preserving linear amplifier is to make a small signal larger, so that it can be perceived by instruments incapable of resolving the original signal, while sacrificing as little as possible in signal-to-noise. Quantum mechanics limits how well this can be done: the noise added by the amplifier, referred to the input, must be at least half a quantum at the operating frequency. This well-known quantum limit only constrains the second moments of the added noise. Here we provide the quantum constraints on the entire distribution of added noise: any phasepreserving linear amplifier is equivalent to a parametric amplifier with a physical state ? for the ancillary mode; ? determines the properties of the added noise.
Enhanced dielectric-wall linear accelerator
Sampayan, S.E.; Caporaso, G.J.; Kirbie, H.C.
1998-09-22
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.
Enhanced dielectric-wall linear accelerator
Sampayan, Stephen E. (Manteca, CA); Caporaso, George J. (Livermore, CA); Kirbie, Hugh C. (Dublin, CA)
1998-01-01
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.
Magnetized static black Saturn
Stoytcho S. Yazadjiev
2008-02-06
We construct a new static solution to the 5D Einstein-Maxwell equations describing a static black hole surrounded by a non-rotating dipole black ring. The configuration is kept in equilibrium by an external magnetic field interacting with the dipole charge of the black ring. The properties of the black Saturn-like configuration are studied and the basic physical quantities are calculated. The solution demonstrates 2-fold continuous non-uniqueness of the 5D magnetized static neutral black objects for fixed total mass and Melvin background.
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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would like submit the followingConcentratingPortalCool Magnetic Molecules PrintCool Magnetic
On the dynamics of magnetic fluids in magnetic resonance imaging
Cantillon-Murphy, Pádraig J
2008-01-01
The hydrodynamics of magnetic fluids, often termed ferrofluids, has been an active area of research since the mid 1960s. However, it is only in the past twenty years that these fluids have begun to be used in magnetic ...
Non-linear Fractal Interpolating Functions
R. Kobes; H. Letkeman
2001-12-07
We consider two non-linear generalizations of fractal interpolating functions generated from iterated function systems. The first corresponds to fitting data using a Kth-order polynomial, while the second relates to the freedom of adding certain arbitrary functions. An escape-time algorithm that can be used for such systems to generate fractal images like those associated with Julia or Mandelbrot sets is also described.
Direct characterization of linear-optical networks
Saleh Rahimi-Keshari; Matthew A. Broome; Robert Fickler; Alessandro Fedrizzi; Timothy C. Ralph; Andrew G. White
2013-05-31
We introduce an efficient method for fully characterizing multimode linear-optical networks. Our approach requires only a standard laser source and intensity measurements to directly and uniquely determine all moduli and non-trivial phases of the matrix describing a network. We experimentally demonstrate the characterization of a $6{\\times}6$ fiber-optic network and independently verify the results via nonclassical two-photon interference.
Three Main Subsystems: I. Centerpiece (Linear Actuation)
van den Berg, Jur
was designed to create an interesting, symmetric path. The linear actuator utilizes an internal power screw. II protection for the moving parts. A bench was added to the design at the bottom of the sculpture. Power- Monocrystalline-Solar-Panel-4-Pack-GS-S-250- Fab5x4/202960000?N=8p9Z5yc1v Left Bottom: Wind Blue Power LLC. (2014
High gradient accelerators for linear light sources
Barletta, W.A.
1988-09-26
Ultra-high gradient radio frequency linacs powered by relativistic klystrons appear to be able to provide compact sources of radiation at XUV and soft x-ray wavelengths with a duration of 1 picosecond or less. This paper provides a tutorial review of the physics applicable to scaling the present experience of the accelerator community to the regime applicable to compact linear light sources. 22 refs., 11 figs., 21 tabs.
The Next Linear Collider: NLC2001
D. Burke et al.
2002-01-14
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.
CLIC e+e- Linear Collider Studies
Dominik Dannheim; Philippe Lebrun; Lucie Linssen; Daniel Schulte; Frank Simon; Steinar Stapnes; Nobukazu Toge; Harry Weerts; James Wells
2012-08-07
This document provides input from the CLIC e+e- linear collider studies to the update process of the European Strategy for Particle Physics. It is submitted on behalf of the CLIC/CTF3 collaboration and the CLIC physics and detector study. It describes the exploration of fundamental questions in particle physics at the energy frontier with a future TeV-scale e+e- linear collider based on the Compact Linear Collider (CLIC) two-beam acceleration technique. A high-luminosity high-energy e+e- collider allows for the exploration of Standard Model physics, such as precise measurements of the Higgs, top and gauge sectors, as well as for a multitude of searches for New Physics, either through direct discovery or indirectly, via high-precision observables. Given the current state of knowledge, following the observation of a \\sim125 GeV Higgs-like particle at the LHC, and pending further LHC results at 8 TeV and 14 TeV, a linear e+e- collider built and operated in centre-of-mass energy stages from a few-hundred GeV up to a few TeV will be an ideal physics exploration tool, complementing the LHC. Two example scenarios are presented for a CLIC accelerator built in three main stages of 500 GeV, 1.4 (1.5) TeV, and 3 TeV, together with the layout and performance of the experiments and accompanied by cost estimates. The resulting CLIC physics potential and measurement precisions are illustrated through detector simulations under realistic beam conditions.
Inpainting with sparse linear combinations of exemplars
Wohlberg, Brendt
2008-01-01
We introduce a new exemplar-based inpainting algorithm based on representing the region to be inpainted as a sparse linear combination of blocks extracted from similar parts of the image being inpainted. This method is conceptually simple, being computed by functional minimization, and avoids the complexity of correctly ordering the filling in of missing regions of other exemplar-based methods. Initial performance comparisons on small inpainting regions indicate that this method provides similar or better performance than other recent methods.
Linear feature selection for multipopulation classification
Havens, Kathryn Anne
1974-01-01
) December 1974 ABSTRACT Linear Feature Selection for Multipopulation Classification. (December 1974) Kathryn A. Havens, B. S. , Lamar University Chairman of Advisory Committee: Dr. L. F. Guseman, Jr. A classification procedure for n...-dimensional normally distributed observation vectors which belong to one of three populations is de- scribed. In particular, a computational procedure is presented for finding a lxn vector B which minimizes the probability of misclassification with respect...
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)
2014-01-28
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.
Damage Identification with Linear Discriminant Operators
Farrar, C.R.; Nix, D.A.; Duffey, T.A.; Cornwell, P.J.; Pardoen, G.C.
1999-02-08
This paper explores the application of statistical pattern recognition and machine learning techniques to vibration-based damage detection. First, the damage detection process is described in terms of a problem in statistical pattern recognition. Next, a specific example of a statistical-pattern-recognition-based damage detection process using a linear discriminant operator, ''Fisher's Discriminant'', is applied to the problem of identifying structural damage in a physical system. Accelerometer time histories are recorded from sensors attached to the system as that system is excited using a measured input. Linear Prediction Coding (LPC) coefficients are utilized to convert the accelerometer time-series data into multi-dimensional samples representing the resonances of the system during a brief segment of the time series. Fisher's discriminant is then used to find the linear projection of the LPC data distributions that best separates data from undamaged and damaged systems. The method i s applied to data from concrete bridge columns as the columns are progressively damaged. For this case, the method captures a clear distinction between undamaged and damaged vibration profiles. Further, the method assigns a probability of damage that can be used to rank systems in order of priority for inspection.
Aleks Kleyn
2015-05-08
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 $A$.
Modular Permanent Magnet Machine Based on Soft Magnetic *** Burgess-Norton Mfg.Co.
Lipo, Thomas
. The rotor structure can be designed with surface permanent magnet (SPM) or internal permanent magnet (IPM
Modeling of magnetic island formation in magnetic reconnection experiment
Ji, Hantao
the spontaneous FRC formation with effective plasma heating by magnetic reconnection.6 In the Magnetic, Gifu, 509-5292, Japan M. Yamada and H. Ji Plasma Physics Laboratory, Princeton University, Princeton found in the Magnetic Reconnection Experiment MRX M. Yamada, H. Ji, S. Hsu, et al., Phys. Plasmas 4
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 of either electron beam deposition and/or focused ion beam milling. Attachment/ growth of carbon nanotubes carbon nanotube MWNT capped with a magnetic catalyst particle onto the apex of a commercial Si cantilever
Mansuripur, Masud
2015-01-01
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...
Linear Collider Physics Resource Book Snowmass 2001
Ronan (Editor), M.T.
2001-06-01
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.
Nimbalkar, Manoj; Neves, Jorge L; Elavarasi, S Begam; Yuan, Haidong; Khaneja, Navin; Dorai, Kavita; Glaser, Steffen J
2011-01-01
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...
Electron Energization in Magnetic Reconnection
Anlage, Steven
Electron Energization in Magnetic Reconnection Wor Thongthai, Department of Physics, University into the surrounding plasma. #12;Motivation · Magnetic reconnection generally regarded responsible for energizing;Conclusion · Electrons are substantially energized when they pass in close proximity to the x
Lensless Imaging of Magnetic Nanostructures
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
28 March 2012 00:00 Magnetism is useful for many devices and techniques, from electric motors and computer hard drives to magnetic resonance imaging used in medicine. By studying...
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...
Ayten, B
2013-01-01
Due to the smallness of the volumes associated with the flux surfaces around the O-point of a magnetic island, the electron cyclotron power density applied inside the island for the stabilization of neoclassical tearing modes (NTMs) can exceed the threshold for non-linear effects as derived previously by Harvey et al, Phys. Rev. Lett. 62 (1989) 426. We study the non-linear electron cyclotron current drive (ECCD) efficiency through bounce-averaged, quasi-linear Fokker-Planck calculations in the magnetic geometry as created by the islands. The calculations are performed for the parameters of a typical NTM stabilization experiment on ASDEX Upgrade. A particular feature of these experiments is that the rays of the EC wave beam propagate tangential to the flux surfaces in the power deposition region. The calculations show significant non-linear effects on the ECCD efficiency, when the ECCD power is increased from its experimental value of 1 MW to a larger value of 4 MW. The nonlinear effects are largest in case of...
Kirol, L.D.
1987-02-11
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.
Kirol, Lance D. (Shelly, ID)
1988-01-01
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.
SU-E-J-233: A Facility for Radiobiological Experiments in a Large Magnetic Field
Carlone, M; Heaton, R; Keller, H; Wouters, B; Jaffray, D
2014-06-01
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 reconnection in nontoroidal plasmas
Boozer, Allen H. [Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027 (United States)
2005-07-15
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.
Ames Lab 101: Magnetic Refrigeration
Pecharsky, Vitalij
2011-01-01
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
2013-03-01
Vitalij Pecharsky, distinguished professor of materials science and engineering, discusses his research in magnetic refrigeration at Ames Lab.
Semiclassical bounds in magnetic bottles
Diana Barseghyan; Pavel Exner; Hynek Kovarik; Timo Weidl
2015-01-13
The aim of the paper is to derive spectral estimates into several classes of magnetic systems. They include three-dimensional regions with Dirichlet boundary as well as a particle in $\\mathbb{R}^3$ confined by a local change of the magnetic field. We establish two-dimensional Berezin-Li-Yau and Lieb-Thirring-type bounds in the presence of magnetic fields and, using them, get three-dimensional estimates for the eigenvalue moments of the corresponding magnetic Laplacians.
Magnetic and structural properties of Zn doped MnV{sub 2}O{sub 4}
Shahi, Prashant; Shukla, K. K.; Singh, Rahul; Chatterjee, Sandip; Das, A.; Ghosh, A. K.; Nigam, A. K.
2014-04-24
The magnetization, Neutron diffraction and X-ray diffraction of Zn doped MnV{sub 2}O{sub 4} as a function of temperature have been measured. It has been observed, with increase of Zn the non-linear orientation of Mn spins with the V spins will decrease which effectively decrease the structural transition temperature more rapidly than Curie Temperature.
An Algorithm for the Simulations of the Magnetized Neutron Star Cooling
Grigorian, H; Chubarian, E; Piloyan, A; Rafayelyan, M
2015-01-01
The model and algorithm for the cooling of the magnetized neutron stars are presented. The cooling evolution described by system of parabolic partial differential equations with non-linear coefficients is solved using Alternating Direction Implicit method. The difference scheme and the preliminary results of simulations are presented.
Magnetic reconnection launcher
Cowan, M.
1987-04-06
An electromagnetic launcher includes a plurality of electrical stages which are energized sequentially in the launcher with the passage of a projectiles. Each stage of the launcher includes two or more coils which are arranged coaxially on either closed-loop or straight lines to form gaps between their ends. The projectile has an electrically conductive gap-portion that passes through all the gaps of all the stages in a direction transverse to the axes of the coils. The coils receive an electric current, store magnetic energy, and convert a significant portion of the stored magnetic energy into kinetic energy of the projectile moves through the gap. The magnetic polarity of the opposing coils is in the same direction, e.g. N-S-N-S. A gap portion of the projectile may be made from aluminum and is propelled by the reconnection of magnetic flux stored in the coils which causes accelerating forces to act upon the projectile and at the horizontal surfaces of the projectile near its rear. The gap portion of the projectile may be flat, rectangular and longer than the length of the opposing coils. The gap portion of the projectile permits substantially unrestricted distribution of the induced currents so that current densities are only high where the useful magnetic force is high. This allows designs which permit ohmic oblation from the rear surfaces of the gap portion of the projectile allowing much high velocities to be achieved. An electric power apparatus controls the electric power supplied to the opposing coils until the gap portion of the projectile substantially occupies the gap between the coils, at which time the coils are supplied with peak current quickly. 8 figs.
Low-temperature magnetic refrigerator
Barclay, J.A.
1983-05-26
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)
1985-01-01
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.
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
Electric field of a point-like charge in a strong magnetic field
A. E. Shabad; V. V. Usov
2006-07-22
We describe the potential produced by a point electric charge placed into a constant magnetic field, so strong that the electron Larmour length is much shorter than its Compton length. The standard Coulomb law is modified due to the vacuum polarization by the external magnetic field. Only mode-2 photons mediate the static interaction. The corresponding vacuum polarization component, taken in the one-loop approximation, grows linearly with the magnetic field. Thanks to this fact a scaling regime occurs in the limit of infinite magnetic field, where the potential is determined by a universal function, independent the magnetic field. The scaling regime implies a short-range character of interaction in the Larmour scale, expressed as a Yukawa law. On the contrary, the electromagnetic interaction regains its long-range character in a larger scale, characterized by the Compton length. In this scale the tail of the Yukawa potential follows an anisotropic Coulomb law: it decreases as the distance from the charge increases, slower along the magnetic field and faster across. The equipotential surface is an ellipsoid stretched along the magnetic field. As a whole, the modified Coulomb potential is a narrower-shaped function than the standard Coulomb function, the narrower the stronger the field. The singular behavior in the vicinity of the charge remains unsuppressed by the magnetic field. These results may be useful for studying atomic spectra in super- strong magnetic fields of several Schwinger's characteristic values.
Magnetic Particle Detection (MPD) for In-Vitro Dosimetry
Minard, Kevin R.; Littke, Matthew H.; Wang, Wei; Xiong, Yijia; Teeguarden, Justin G.; Thrall, Brian D.
2013-05-15
In-vitro tests intended for evaluating the potential health effects of magnetic nanoparticles generally require an accurate measure of cell dose to promote the consistent use and interpretation of biological response. Here, a simple low-cost inductive sensor is developed for quickly determining the total mass of magnetic nanoparticles that is bound to the plasma membrane and internalized by cultured cells. Sensor operation exploits an oscillating magnetic field (f0 = 250 kHz) together with the nonlinear response of particle magnetization to generate a harmonic signal (f3 = 750 kHz) that varies linearly with particulate mass (R2 > 0.999) and is sufficiently sensitive for detecting ~ 100 ng of carboxyl-coated iron-oxide nanoparticles in under a second. When exploited for measuring receptor-mediated nanoparticle uptake in RAW 264.7 macrophages, results show that achieved dosimetry performance is comparable with relatively expensive analytical techniques that are much more time-consuming and labor-intensive to perform. Described sensing is therefore potentially better suited for low-cost in-vitro assays that require fast and quantitative magnetic particle detection.
Electrostatic waves in carbon nanotubes with an axial magnetic field
Abdikian, Alireza; Bagheri, Mehran
2013-10-15
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.
Wireless Magnetic Sensor Applications in Transportation Infrastructure
Sanchez, Rene Omar
2012-01-01
of wireless magnetic sensors in Intelligent Trans- portationof wireless magnetic sensors in Intelligent Transportationmagnetic sensors for different Intelligent Transportation
Micromechanism linear actuator with capillary force sealing
Sniegowski, Jeffry J. (Albuquerque, NM)
1997-01-01
A class of micromachine linear actuators whose function is based on gas driven pistons in which capillary forces are used to seal the gas behind the piston. The capillary forces also increase the amount of force transmitted from the gas pressure to the piston. In a major subclass of such devices, the gas bubble is produced by thermal vaporization of a working fluid. Because of their dependence on capillary forces for sealing, such devices are only practical on the sub-mm size scale, but in that regime they produce very large force times distance (total work) values.
Physics at the $e^+ e^-$ Linear Collider
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Moortgat-Picka, G.; Kronfeld, A. S.
2015-08-14
A comprehensive review of physics at an e+e? linear collider in the energy range of s?=92 GeV–3 TeV is presented in view of recent and expected LHC results, experiments from low-energy as well as astroparticle physics. The report focusses in particular on Higgs-boson, top-quark and electroweak precision physics, but also discusses several models of beyond the standard model physics such as supersymmetry, little Higgs models and extra gauge bosons. The connection to cosmology has been analysed as well.
Linearized Non-Minimal Higher Curvature Supergravity
Fotis Farakos; Alex Kehagias; Konstantinos Koutrolikos
2015-01-29
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.
Sums in linear algebraic lambda-calculus
Díaz-Caro, Alejandro
2010-01-01
In this paper we define the confluent additive fragment of the linear-algebraic lambda-calculus. We also define a fine-grained type system which includes sums of types as a reflection of those in the terms. After proving the subject reduction and strong normalisation properties, we study the role of sums within the calculus by interpreting our system into System F with pairs. We show that this calculus can be interpreted as System F with an associative and commutative pair constructor, which is distributive under application.
Beyond linear gyrocenter polarization in gyrokinetic theory
Brizard, Alain J. [Department of Physics, Saint Michael's College, Colchester, Vermont 05439 (United States)] [Department of Physics, Saint Michael's College, Colchester, Vermont 05439 (United States)
2013-09-15
The concept of polarization in gyrokinetic theory is clarified and generalized to include contributions from the guiding-center (zeroth-order) polarization as well as the nonlinear (second-order) gyrocenter polarization. The guiding-center polarization, which appears as the antecedent (zeroth-order) of the standard linear (first-order) gyrocenter polarization, is obtained from a modified guiding-center transformation. The nonlinear gyrocenter polarization is derived either variationally from the third-order gyrocenter Hamiltonian or directly by gyrocenter push-forward method.
Physics at the International Linear Collider
J. List
2006-05-18
The International Linear Collider (ILC) is the next large project in accelerator based particle physics. It is complementary to the LHC in many aspects. Measurements from both machines together will finally shed light onto the known deficiencies of the Standard Model of particle physics and allow to unveil a possible underlying more fundamental theory. Here, the possibilities of the ILC will be discussed with special emphasis on the Higgs sector and on topics with a strong connection to cosmological questions like extra dimensions or dark matter candidates.
Positron Polarization at the International Linear Collider
P. Osland; N. Paver
2005-07-15
We review some recent arguments supporting the upgrade of the International Linear Collider by a polarized positron beam, in addition to the polarized electron beam. The examples presented here mainly focus on the impact of positron polarization on items relevant to new physics searches, such as the identification of novel interactions in fermion-pair production and the formulation of new CP-sensitive observables. In particular, in addition to the benefits from positron and electron longitudinal polarizations, the advantages in this field of having transverse polarization of both beams are emphasized.