Collisionless Spectral Kinetic Simulation of Ideal Multipole Resonance Probe
Gong, Junbo; Wilczek, Sebastian; Szeremley, Daniel; Oberrath, Jens; Eremin, Denis; Dobrygin, Wladislaw; Schilling, Christian; Friedrichs, Michael; Brinkmann, Ralf Peter
2016-09-01
Active Plasma Resonance Spectroscopy denotes a class of industry-compatible plasma diagnostic methods which utilize the natural ability of plasmas to resonate on or near the electron plasma frequency ωpe. One particular realization of APRS with a high degree of geometric and electric symmetry is the Multipole Resonance Probe (MRP). The Ideal MRP(IMRP) is an even more symmetric idealization which is suited for theoretical investigations. In this work, a spectral kinetic scheme is presented to investigate the behavior of the IMRP in the low pressure regime. However, due to the velocity difference, electrons are treated as particles whereas ions are only considered as stationary background. In the scheme, the particle pusher integrates the equations of motion for the studied particles, the Poisson solver determines the electric field at each particle position. The proposed method overcomes the limitation of the cold plasma model and covers kinetic effects like collisionless damping.
Planar Multipol-Resonance-Probe: A Spectral Kinetic Approach
Friedrichs, Michael; Gong, Junbo; Brinkmann, Ralf Peter; Oberrath, Jens; Wilczek, Sebastian
2016-09-01
Measuring plasma parameters, e.g. electron density and electron temperature, is an important procedure to verify the stability and behavior of a plasma process. For this purpose the multipole resonance probe (MRP) represents a satisfying solution to measure the electron density. However the influence of the probe on the plasma through its physical presence makes it unattractive for some processes in industrial application. A solution to combine the benefits of the spherical MRP with the ability to integrate the probe into the plasma reactor is introduced by the planar model of the MRP (pMRP). Introducing the spectral kinetic formalism leads to a reduced simulation-circle compared to particle-in-cell simulations. The model of the pMRP is implemented and first simulation results are presented.
Multiphonon giant resonances in nuclei
Aumann, T. [Mainz Univ. (Germany). Inst. fuer Kernchemie; Bortignon, P.F. [Milan Univ. (Italy). Dipt. di Fisica]|[Istituto Nazionale di Fisica Nucleare, Milan (Italy); Emling, H. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)
1998-07-01
We review the present knowledge of multiphonon giant resonances in nuclei. Theoretical concepts approaching the intrinsic structure and excitation mechanisms of multi-phonon states are discussed. The available experimental results are summarized, including a brief description of applied techniques. This review emphasizes electromagnetic excitations of double dipole resonances. Open questions and possible routes toward a solution are addressed. (orig.)
Lim, Wen Xiang; Han, Song; Gupta, Manoj; MacDonald, Kevin F.; Singh, Ranjan
2017-08-01
We report on an experimental and computational (multipole decomposition) study of Fano resonance modes in complementary near-IR plasmonic metamaterials. Resonance wavelengths and linewidths can be controlled by changing the symmetry of the unit cell so as to manipulate the balance among multipole contributions. In the present case, geometrically inverting one half of a four-slot (paired asymmetric double bar) unit cell design changes the relative magnitude of magnetic quadrupole and toroidal dipole contributions leading to the enhanced quality factor, figure of merit, and spectral tuning of the plasmonic Fano resonance.
Deformation effects in Giant Monopole Resonance
Kvasil, J; Repko, A; Bozik, D; Kleinig, W; Reinhard, P -G
2014-01-01
The isoscalar giant monopole resonance (GMR) in Samarium isotopes (from spherical $^{144}$Sm to deformed $^{148-154}$Sm) is investigated within the Skyrme random-phase-approximation (RPA) for a variety of Skyrme forces. The exact RPA and its separable version (SRPA) are used for spherical and deformed nuclei, respectively. The quadrupole deformation is shown to yield two effects: the GMR broadens and attains a two-peak structure due to the coupling with the quadrupole giant resonance.
Multipoles of Even/Odd Split-Ring Resonators
Andrew Chen
2015-08-01
Full Text Available The ultimate goal of metamaterial engineering is to have complete control over the electromagnetic constitutive parameters in three-dimensional space. This engineering can be done by considering either single meta-atoms or full meta-arrays. We follow the first route and perform numerical simulations of split-ring resonators, with different gap numbers and under varying illumination scenarios, to investigate their individual multipolar scattering response. For the fundamental resonance, we observe that odd-gap rings always exhibit overlapping electric and magnetic dipole responses while even-gap rings only exhibit that behavior accidentally. We expect our results to foster progress in the engineering of three-dimensional disordered metamaterials.
Patel, D; Itoh, M; Akimune, H; Berg, G P A; Fujiwara, M; Harakeh, M N; Iwamoto, C; Kawabata, T; Kawase, K; Matta, J T; Murakami, T; Okamoto, A; Sako, T; Schlax, K W; Takahashi, K; White, M; Yosoi, M
2014-01-01
The excitation of the isoscalar giant monopole resonance (ISGMR) in $^{116}$Sn and $^{208}$Pb has been investigated using small-angle (including $0^\\circ$) inelastic scattering of 100 MeV/u deuteron and multipole-decomposition analysis (MDA). The extracted strength distributions agree well with those from inelastic scattering of 100 MeV/u $\\alpha$ particles. These measurements establish deuteron inelastic scattering at E$_d \\sim$ 100 MeV/u as a suitable probe for extraction of the ISGMR strength with MDA, making feasible the investigation of this resonance in radioactive isotopes in inverse kinematics.
Enhancing monochromatic multipole emission by a subwavelength enclosure of degenerate Mie resonances
Zhao, Jiajun
2017-07-06
Sound emission is inefficient at low frequencies as limited by source size. This letter presents enhancing emission of monochromatic monopole and multipole sources by enclosing the source with a subwavelength circular enclosure filled of an anisotropic material of a low radial sound speed. The anisotropy is associated with an infinite tangential density along the azimuth. Numerical simulations show that emission gain is produced at frequencies surrounding degenerate Mie resonant frequencies of the enclosure, and meanwhile the radiation directivity pattern is well preserved. The degeneracy is theoretically analyzed. A realization of the material is suggested by using a space-coiling structure.
Anharmonic effects and double giant dipole resonances
Voronov, V V
2001-01-01
A brief review of recent results of the microscopic calculations to describe characteristics of the double giant dipole resonances (DGDR) is presented. A special attention is paid to a microscopic study of the anharmonic properties of the DGDR. It is found that the deviation of the energy centroid of the DGDR from the harmonic limit follows A sup - sup 1 dependence
Itoh, M; Sakaguchi, H; Akimune, H; Fujiwara, M; Garg, U; Hara, K; Hashimoto, H; Hoffman, J; Kawabata, T; Kawase, K; Murakami, T; Nakanishi, K; Nayak, B K; Terashima, S; Uchida, M; Yasuda, Y; Yosoi, M
2013-01-01
Isoscalar giant resonances and low spin states in $^{32}$S have been measured with inelastic $\\alpha$ scattering at extremely forward angles including zero degrees at E$_{\\alpha}$ = 386 MeV. By applying the multipole decomposition analysis, various excited states are classified according to their spin and parities (J$^{\\pi}$), and are discussed in relation to the super deformed and $^{28}$Si + $\\alpha$ cluster bands.
Friedrichs, Michael; Brinkmann, Ralf Peter; Oberrath, Jens
2016-09-01
Measuring plasma parameters, e.g. electron density and electron temperature, is an important procedure to verify the stability and behavior of a plasma process. For this purpose the multipole resonance probe (MRP) represents a satisfying solution to measure the electron density. However the influence of the probe on the plasma through its physical presence makes it unattractive for some processes in industrial application. A solution to combine the benefits of the spherical MRP with the ability to integrate the probe into the plasma reactor is introduced by the planar model of the MRP. By coupling the model of the cold plasma with the maxwell equations for electrostatics an analytical model for the admittance of the plasma is derivated, adjusted to cylindrical geometry and solved analytically for the planar MRP using functional analytic methods.
Oberberg, Moritz; Styrnoll, Tim; Ries, Stefan; Bienholz, Stefan; Awakowicz, Peter
2015-09-01
Reactive sputter processes are used for the deposition of hard, wear-resistant and non-corrosive ceramic layers such as aluminum oxide (Al2O3) . A well known problem is target poisoning at high reactive gas flows, which results from the reaction of the reactive gas with the metal target. Consequently, the sputter rate decreases and secondary electron emission increases. Both parameters show a non-linear hysteresis behavior as a function of the reactive gas flow and this leads to process instabilities. This work presents a new control method of Al2O3 deposition in a multiple frequency CCP (MFCCP) based on plasma parameters. Until today, process controls use parameters such as spectral line intensities of sputtered metal as an indicator for the sputter rate. A coupling between plasma and substrate is not considered. The control system in this work uses a new plasma diagnostic method: The multipole resonance probe (MRP) measures plasma parameters such as electron density by analyzing a typical resonance frequency of the system response. This concept combines target processes and plasma effects and directly controls the sputter source instead of the resulting target parameters.
Patel, D.; Garg, U. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, IN 46556 (United States); Itoh, M. [Cyclotron and Radioisotope Center, Tohoku University, Sendai 980-8578 (Japan); Akimune, H. [Department of Physics, Konan University, Kobe 568-8501 (Japan); Berg, G.P.A. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, IN 46556 (United States); Fujiwara, M. [Research Center for Nuclear Physics, Osaka University, Osaka 567-0047 (Japan); Harakeh, M.N. [Kernfysisch Versneller Instituut, University of Groningen, 9747 AA Groningen (Netherlands); GANIL, CEA/DSM-CNRS/IN2P3, 14076 Caen (France); Iwamoto, C. [Department of Physics, Konan University, Kobe 568-8501 (Japan); Kawabata, T. [Division of Physics and Astronomy, Kyoto University, Kyoto 606-8502 (Japan); Kawase, K. [Japan Atomic Energy Agency, Kyoto 619-0215 (Japan); Matta, J.T. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Joint Institute for Nuclear Astrophysics, University of Notre Dame, Notre Dame, IN 46556 (United States); Murakami, T. [Division of Physics and Astronomy, Kyoto University, Kyoto 606-8502 (Japan); Okamoto, A. [Department of Physics, Konan University, Kobe 568-8501 (Japan); Sako, T. [Japan Atomic Energy Agency, Kyoto 619-0215 (Japan); Schlax, K.W. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Takahashi, F. [Research Center for Nuclear Physics, Osaka University, Osaka 567-0047 (Japan); White, M. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Yosoi, M. [Research Center for Nuclear Physics, Osaka University, Osaka 567-0047 (Japan)
2014-07-30
The excitation of the isoscalar giant monopole resonance (ISGMR) in {sup 208}Pb and {sup 116}Sn has been investigated using small-angle (including 0°) inelastic scattering of 100 MeV/u deuteron and multipole-decomposition analysis (MDA). The extracted strength distributions agree well with those from inelastic scattering of 100 MeV/u α particles. These measurements establish deuteron inelastic scattering at E{sub d}∼100 MeV/u as a suitable probe for extraction of the ISGMR strength with MDA, making feasible the investigation of this resonance in radioactive isotopes in inverse kinematics.
Double giant dipole resonance in hot nuclei
Cinausero, M.; Rizzi, V.; Viesti, G.; Fabris, D.; Lunardon, M.; Moretto, S.; Nebbia, G.; Pesente, S.; Barbui, M.; Fioretto, E.; Prete, G.; Bracco, A.; Camera, F.; Million, B.; Leoni, S.; Wieland, O.; Benzoni, G.; Brambilla, S.; Airoldi, A.; Maj, A.; Kmiecik, M
2004-02-09
Signals from Double Dipole Giant Resonances (DGDR) in hot nuclei have been searched in a {gamma}-{gamma} coincidence experiment using the HECTOR array at the Laboratori Nazionali di Legnaro. The experimental single {gamma}-ray spectrum and the projection of the {gamma}-{gamma} matrix have been compared with a standard Monte Carlo Statistical Model code including only the single GDR excitation. These calculations have been used as background to determine the extra-yield associated with the DGDR de-excitation. Results have been compared with a previous experiment confirming the presence of the DGDR excitation in fusion-evaporation reactions.
Giant dipole resonance studied with GASP
Cinausero, M. [Istituto Nazionale di Fisica Nucleare, Legnaro (Italy). Lab. Nazionali di Legnaro; Bazzacco, D. [Dipartimento di Fisica, I.N.F.N., Sezione di Padova, 35131, Padova (Italy); Bortignon, P.F. [Dipartimento di Fisica, I.N.F.N., Sezione di Milano, 20133, Milano (Italy); De Angelis, G. [Istituto Nazionale di Fisica Nucleare, Legnaro (Italy). Lab. Nazionali di Legnaro; Fabris, D. [Dipartimento di Fisica, I.N.F.N., Sezione di Padova, 35131, Padova (Italy); Fiore, E.M. [Dipartimento di Fisica, I.N.F.N., Sezione di Bari, 70126, Bari (Italy); Fiore, L. [Dipartimento di Fisica, I.N.F.N., Sezione di Bari, 70126, Bari (Italy); Fioretto, E. [Istituto Nazionale di Fisica Nucleare, Legnaro (Italy). Lab. Nazionali di Legnaro; Fornal, B. [Institute of Nuclear Physics, 31342, Cracow (Poland); Gelli, N. [Dipartimento di Fisica, I.N.F.N., Sezione di Firenze, 50125, Firenze (Italy); Lops, M. [Dipartimento di Fisica, I.N.F.N., Sezione di Padova, 35131, Padova (Italy); Lucarelli, F. [Dipartimento di Fisica, I.N.F.N., Sezione di Firenze, 50125, Firenze (Italy); Lunardi, S. [Dipartimento di Fisica, I.N.F.N., Sezione di Padova, 35131, Padova (Italy); Nebbia, G. [Dipartimento di Fisica, I.N.F.N., Sezione di Padova, 35131, Padova (Italy); Paticchio, V. [Dipartimento di Fisica, I.N.F.N., Sezione di Bari, 70126, Bari (Italy); Prete, G. [Istituto Nazionale di Fisica Nucleare, Legnaro (Italy). Lab. Nazionali di Legnaro; Rossi-Alvarez, C. [Dipartimento di Fisica, I.N.F.N., Sezione di Padova, 35131, Padova (Italy); Viesti, G. [Dipartimento di Fisica, I.N.F.N., Sezione di Padova, 35131, Padova (Italy)
1996-03-18
The giant dipole resonance (GDR) from the decay of excited {sup 156}Er nuclei populated in the reaction {sup 64}Ni+{sup 92}Zr at 241 MeV has been studied by using the GASP spectrometer. High-energy {gamma}-ray spectra have been obtained in coincidence with the 80 elements of the GASP inner ball and with discrete transitions in the residual nuclei {sup 155,154}Er. GDR parameters extracted from the high-energy {gamma}-ray spectra in coincidence with low-energy {gamma}-ray fold k>10 are in good agreement with systematics as well as with predictions from adiabatic calculations. No signature for entrance channel effects in the decay of {sup 156}Er was therefore observed from this lineshape analysis of the high-energy {gamma}-ray spectra in contrast with the case of the {sup 164}Yb nucleus. (orig.).
Giant dipole resonance in hot rotating nuclei
Chakrabarty, D.R. [Bhabha Atomic Research Centre, Nuclear Physics Division, Mumbai (India); Dinh Dang, N. [RIKEN, Nishina Centre for Accelerator-based Science, Saitama (Japan); VINATOM, Institute of Nuclear Science and Technique, Hanoi (Viet Nam); Datar, V.M. [Tata Institute of Fundamental Research, INO Cell, Mumbai (India)
2016-05-15
Over the last several decades, extensive experimental and theoretical work has been done on the giant dipole resonance (GDR) in excited nuclei covering a wide range of temperature (T), angular momentum (J) and nuclear mass. A reasonable stability of the GDR centroid energy and an increase of the GDR width with T (in the range∝1-3 MeV) and J are the two well-established results. Some experiments have indicated the saturation of the GDR width at high T. The gradual disappearance of the GDR vibration at much higher T has been observed. Experiments on the Jacobi transition and the GDR built on superdeformed shapes at high rotational frequencies have been reported in a few cases. Theoretical calculations on the damping of the collective dipole vibration, characterised by the GDR width, have been carried out within various models such as the thermal shape fluctuation model and the phonon damping model. These models offer different interpretations of the variation of the GDR width with T and J and have met with varying degrees of success in explaining the experimental data. In this review, the present experimental and theoretical status in this field is discussed along with the future outlook. The interesting phenomenon of the pre-equilibrium GDR excitation in nuclear reactions is briefly addressed. (orig.)
Chattaraj, Swarnabha
2016-01-01
We present an analysis of the optical response of a class of on-chip integrated nano-photonic systems comprising all-dielectric building block based multifunctional light manipulating units (LMU) integrated with quantum dot (QD) light sources. The multiple functions (such as focusing excitation light, QD emission rate enhancement, photon guidance, and lossless propagation) are simultaneously realized using the collective Mie resonances of dipole and higher order multipole modes of the dielectric building blocks (DBBs) constituting a single structural unit, the LMU. Using analytical formulation based on Mie theory we demonstrate enhancement of the excitation light simultaneously with the guiding and propagation of the emitted light from a QD emitter integrated with the DBB based LMU. The QD-DBB integrated structures can serve as the basic element for building nano-optical active circuits for optical information processing in both classical and quantum realms.
Nonlinear dynamics of giant resonances in atomic nuclei
Vretenar, D; Ring, P; Lalazissis, G A
1999-01-01
The dynamics of monopole giant resonances in nuclei is analyzed in the time-dependent relativistic mean-field model. The phase spaces of isoscalar and isovector collective oscillations are reconstructed from the time-series of dynamical variables that characterize the proton and neutron density distributions. The analysis of the resulting recurrence plots and correlation dimensions indicate regular motion for the isoscalar mode, and chaotic dynamics for the isovector oscillations. Information-theoretic functionals identify and quantify the nonlinear dynamics of giant resonances in quantum systems that have spatial as well as temporal structure.
Thermal pairing and giant dipole resonance in highly excited nuclei
Dang, Nguyen Dinh
2014-01-01
Recent results are reported showing the effects of thermal pairing in highly excited nuclei. It is demonstrated that thermal pairing included in the phonon damping model (PDM) is responsible for the nearly constant width of the giant dipole resonance (GDR) at low temperature $T $ 170 MeV.
Temperature Dependence of Spreading Width of Giant Dipole Resonance
Storozhenko, A N; Ventura, A; Blokhin, A I
2002-01-01
The Quasiparticle-Phonon Nuclear Model extended to finite temperature within the framework of Thermo Field Dynamics is applied to calculate a temperature dependence of the spreading width Gamma^{\\downarrow} of a giant dipole resonance. Numerical calculations are made for ^{120}Sn and ^{208}Pb nuclei. It is found that Gamma^{\\downarrow} increases with T. The reason of this effect is discussed as well as a relation of the present approach to other ones, existing in the literature.
Giant right atrial myxoma: characterization with cardiac magnetic resonance imaging.
Ridge, Carole A
2012-02-01
A 53-year-old woman presented to the emergency department with a 2-week history of dyspnoea and chest pain. Computed tomography pulmonary angiography was performed to exclude acute pulmonary embolism (PE). This demonstrated a large right atrial mass and no evidence of PE. Transthoracic echocardiography followed by cardiac magnetic resonance imaging confirmed a mobile right atrial mass. Surgical resection was then performed confirming a giant right atrial myxoma. We describe the typical clinical, radiologic, and pathologic features of right atrial myxoma.
Isobar giant resonance formation in self-conjugate nuclei
Townsend, L. W.; Deutchman, P. A.
1981-03-01
The production of isobars with concomitant giant resonance excitations due to peripheral collisions of relativistic heavy ions is investigated. The interaction is described by a modified form of the central term in the one-pion-exchange potential (OPEP) where the projectile ordinary spin operator is replaced by a transition spin operator which describes the creation of an isobar from a nucleon. The scattering is analyzed using time-dependent harmonic perturbation theory to determine the reaction total cross sections. The results obtained, which are valid for reactions involving self-conjugate nuclei, are applied to the specific collison of 2.1 {GeV}/{nucleon}16O projectiles with 12C targets at rest. Cross sections are investigated using two different models for the nuclear spin states. In the first model, the many-body nuclear spin state is reduced, in the spirit of a particle-hole state, to an equivalent two-body state called a particle-core state. In the second model, the many-body spin states are described by unsymmetrized products of individual particle spins. Properties of the spin giant resonance and isobar giant resonance states are investigated. Finally, isobar decay and isobar/pion absorption effects are discussed.
Nuclear Structure aspects of gamma decay from giant resonances
Bracco A.
2014-01-01
Full Text Available The gamma decay of the giant dipole resonance (including its tail region is an important tool to probe the properties of these states, and thus to test the predictions of mean field theories. This paper focuses on two main aspects concerning the electric dipole excitation in nuclei. These are the study of the isospin character of the low energy tail of the Giant Dipole Resonance (GDR, the so-called Pygmy resonance, and the isospin mixing of nuclear systems at finite temperature. In the first case, the Pygmy resonance has been populated in the inelastic scattering reaction 17O+124Sn at 20 MeV/u. Its gamma decay has been measured using the AGATA Demonstrator and an array of 8 large volume LaBr3:Ce scintillators. In the second case, the gamma decay of the GDR in thermalized nuclear systems, formed in fusion evaporation reactions, has been used to investigate the isospin mixing in 80Zr. For this work the reactions 40Ca+40Ca at 3.4 MeV/u and 37Cl +44Ca at 2.6 MeV/u were used.
Brown, K. A. [Brookhaven National Lab. (BNL), Upton, NY (United States); Schoefer, V. [Brookhaven National Lab. (BNL), Upton, NY (United States); Tomizawa, M. [High Energy Accelerator Research Organization (KEK), Tsukuba (Japan)
2017-03-09
The new accelerator complex at J-PARC will operate with both high energy and very high intensity proton beams. With a design slow extraction efficiency of greater than 99% this facility will still be depositing significant beam power onto accelerator components [2]. To achieve even higher efficiencies requires some new ideas. The design of the extraction system and the accelerator lattice structure leaves little room for improvement using conventional techniques. In this report we will present one method for improving the slow extraction efficiency at J-PARC by adding duodecapoles or octupoles to the slow extraction system. We will review the theory of resonant extraction, describe simulation methods, and present the results of detailed simulations. From our investigations we find that we can improve extraction efficiency and thereby reduce the level of residual activation in the accelerator components and surrounding shielding.
Tailoring the multipoles in THz toroidal metamaterials
Cong, Longqing; Srivastava, Yogesh Kumar; Singh, Ranjan
2017-08-01
The multipoles play a significant role in determining the resonant behavior of subwavelength resonators that form the basis of metamaterial and plasmonic systems. Here, we study the impact of multipoles including toroidal dipole on the resonance intensity and linewidth of the fundamental inductive-capacitance (LC) resonance of a metamaterial array. The dominant multipoles that strongly contribute to the resonances are tailored by spatial rearrangement of the neighboring resonators such that the mutual interactions between the magnetic, electric, and toroidal configurations lead to enormous change in the linewidth as well as the resonance intensity of the LC mode. Manipulation of the multipoles in a metamaterial array provides a general strategy for the optimization of the quality factor of metamaterial resonances, which is fundamental to its applications in broad areas of sensing, lasing and nonlinear optics where stronger field confinement plays a significant role.
Excitation-energy dependence of the giant dipole resonance width
Enders, G.; Berg, F. D.; Hagel, K.; Kühn, W.; Metag, V.; Novotny, R.; Pfeiffer, M.; Schwalb, O.; Charity, R. J.; Gobbi, A.; Freifelder, R.; Henning, W.; Hildenbrand, K. D.; Holzmann, R.; Mayer, R. S.; Simon, R. S.; Wessels, J. P.; Casini, G.; Olmi, A.; Stefanini, A. A.
1992-07-01
High-energy γ rays have been measured in coincidence with heavy fragents in deeply inelastic reactions of 136Xe+48Ti at 18.5 MeV/nucleon. The giant dipole resonance (GDR) strength function is deduced from an analysis of the photon spectra within the statistical model. The GDR width Γ is studied as a function of the fragment excitation energy E*. A saturation at about Γ=10 MeV is observed for E*/A>=1.0 MeV/nucleon.
Excitation-energy dependence of the giant dipole resonance width
Enders, G.; Berg, F.D.; Hagel, K.; Kuehn, W.; Metag, V.; Novotny, R.; Pfeiffer, M.; Schwalb, O. (II. Physikalisches Institut, Universitaet, Giessen, Giessen (Germany)); Charity, R.J.; Gobbi, A.; Freifelder, R.; Henning, W.; Hildenbrand, K.D.; Holzmann, R.; Mayer, R.S.; Simon, R.S.; Wessels, J.P. (Gesellschaft fuer Schwerionenforschung Darmstadt, Darmstadt (Germany)); Casini, G.; Olmi, A.; Stefanini, A.A. (Istituto Nazionale di Fisica Nucleare and University of Florence, Florence (Italy))
1992-07-13
High-energy {gamma} rays have been measured in coincidence with heavy fragents in deeply inelastic reactions of {sup 136}Xe+{sup 48}Ti at 18.5 MeV/nucleon. The giant dipole resonance (GDR) strength function is deduced from an analysis of the photon spectra within the statistical model. The GDR width {Gamma} is studied as a function of the fragment excitation energy {ital E}{sup *}. A saturation at about {Gamma}=10 MeV is observed for {ital E}{sup *}/{ital A}{ge}1.0 MeV/nucleon.
Continuum TDHF calculation of Isoscalar and Isovector Giant Monopole Resonances
Stevenson, P D
2013-01-01
We motivate and summarise some recent results in the application of formally exact boundary conditions in nuclear time-dependent Hartree-Fock calculations, making use of Laplace transformations to calculate the values of the wave functions at the boundaries. We have realised the method in the case of giant monopole resonances of spherically-symmetric nuclei, and present strength functions of O-16 and Ca-40 using a simplified version of the Skyrme force, showing that no artefacts from discretisation occur as contaminants
Destruction and Resurrection of Atomic Giant resonances in Endohedral Atoms A@C60
Amusia, M Ya; Chernysheva, L V
2007-01-01
It is demonstrated that in photoabsorption by endohedral atoms some atomic Giant resonances are almost completely destroyed while the others are totally preserved due to different action on it of the fullerenes shell. As the first example we discuss the 4d10 Giant resonance in Xe@C60 whereas as the second serves the Giant autoionization resonance in Eu@C60. The qualitative difference comes from the fact that photoelectrons from the 4d Giant resonance has small energies (tens of eV) and are strongly reflected by the C60 fullerenes shell. As to the Eu@C60, Giant autoionization leads to fast photoelectrons (about hundred eV) that go out almost untouched by the C60 shell. As a result of the outgoing electrons energy difference the atomic Giant resonances will be largely destroyed in A@C60 while the Giant autoionization resonance will be almost completely preserved. Thus, on the way from Xe@C60 Giant resonance to Eu@C60 Giant autoionization resonance the oscillation structure should disappear. Similar will be the ...
Andresen, G. B.; Bertsche, W.; Bray, C. C.; Butler, E.; Cesar, C. L.; Chapman, S.; Charlton, M.; Fajans, J.; Fujiwara, M. C.; Gill, D. R.; Hardy, W. N.; Hayano, R. S.; Hayden, M. E.; Humphries, A. J.; Hydomako, R.; Jørgensen, L. V.; Kerrigan, S. J.; Keller, J.; Kurchaninov, L.; Lambo, R.; Madsen, N.; Nolan, P.; Olchanski, K.; Olin, A.; Povilus, A.; Pusa, P.; Robicheaux, F.; Sarid, E.; El Nasr, S. Seif; Silveira, D. M.; Storey, J. W.; Thompson, R. I.; van der Werf, D. P.; Wurtele, J. S.; Yamazaki, Y.
2009-10-01
In many antihydrogen trapping schemes, antiprotons held in a short-well Penning-Malmberg trap are released into a longer well. This process necessarily causes the bounce-averaged rotation frequency Ω¯r of the antiprotons around the trap axis to pass through zero. In the presence of a transverse magnetic multipole, experiments and simulations show that many antiprotons (over 30% in some cases) can be lost to a hitherto unidentified bounce-resonant process when Ω¯r is close to zero.
Andresen, G B; Bray, C; Butler, E; Cesar, C L; Chapman, S; Charlton, M; Fajans, J; Fujiwara, M C; Gill, D R; Hardy, W N; Hayano, R S; Hayden, M E; Humphries, A J; Hydomako, R; Jørgensen, L V; Kerrigan, S J; Keller, J; Kurchaninov, L; Lambo, R; Madsen, N; Nolan, P; Olchanski, K; Olin, A; Povilus, A; Pusa, P; Robicheaux, F; Sarid, E; Seif El Nasr, S; Silveira, D M; Storey, J W; Thompson, R I; van der Werf, D P; Wurtele, J S; Yamazaki, Y
2009-01-01
In many antihydrogen trapping schemes, antiprotons held in a short-well Penning–Malmberg trap are released into a longer well. This process necessarily causes the bounce-averaged rotation frequency $\\overline{\\Omega}_r$ of the antiprotons around the trap axis to pass through zero. In the presence of a transverse magnetic multipole, experiments and simulations show that many antiprotons (over 30% in some cases) can be lost to a hitherto unidentified bounce-resonant process when $\\overline{\\Omega}_r$ is close to zero.
On direct proton decay of the Gamow-Teller giant resonance
Urin M.H.
2012-12-01
Full Text Available The semi-microscopic approach to the description of giant resonances in medium-heavy mass closed-shell nuclei is implemented to treat partial probabilities of direct-proton decay of the Gamow-Teller giant resonance (GTGR in 208Bi. The corresponding experimental data are reasonably explained.
Structure and direct decay of Giant Monopole Resonances
Avez, Benoît
2013-01-01
We study structure and direct decay of the Giant Monopole Resonance (GMR) using the Time-Dependent Energy-Density-Functional method in the linear response regime in a few doubly-magic nuclei. In these calculations, a proper treatment of the continuum, through the use of large coordinate space, allows for a separation between the nucleus and its emitted nucleons. The microscopic structure of the GMR is investigated with the decomposition of the strength function into individual single-particles quantum numbers. A similar microscopic decomposition of the spectra of emitted nucleons by direct decay of the GMR is performed. Shifting every contribution by the initial sinle-particle energy allows to reconstruct the GMR strength function. The RPA residual interaction couples bound 1-particle 1-hole states to unbound ones, allowing for the total decay of the GMR.
Driving Rabi oscillations at the giant dipole resonance in xenon
Pabst, Stefan; Santra, Robin
2015-01-01
Free-electron lasers (FELs) produce short and very intense light pulses in the XUV and x-ray regimes. We investigate the possibility to drive Rabi oscillations in xenon with an intense FEL pulse by using the unusually large dipole strength of the giant-dipole resonance (GDR). The GDR decays within less than 30 as due to its position, which is above the $4d$ ionization threshold. We find that intensities around 10$^{18}$ W/cm$^2$ are required to induce Rabi oscillations with a period comparable to the lifetime. The pulse duration should not exceed 100 as because xenon will be fully ionized within a few lifetimes. Rabi oscillations reveal themselves also in the photoelectron spectrum in form of Autler-Townes splittings extending over several tens of electronvolt.
Giant resonances in the {sup 26}Mg(e,e{sup {prime}}{alpha}{sub 0}){sup 22}Ne reaction
Terremoto, L.A.; Likhachev, V.P.; Martins, M.N.; Emrich, H.J.; Fricke, G.; Kroehl, T.; Neff, K.W. [Laboratorio do Acelerador Linear, Instituto de Fisica da Universidade de Sao Paulo, Caixa Postal 66318, 05315-970 Sao Paulo, SP (Brazil)
1997-11-01
The fivefold differential cross section of the reaction {sup 26}Mg(e,e{sup {prime}}c) was measured for transferred momenta of 0.35 and 0.54fm{sup {minus}1} and emitted particle angles from {minus}10{degree} to 270{degree} with respect to the transferred-momentum direction. Angular correlation functions for the emitted {alpha}{sub 0} were obtained from the data. A model-independent analysis allowed us to obtain the E0, E1, and E2 multipole components of the {sup 26}Mg(e,e{sup {prime}}{alpha}{sub 0}){sup 22}Ne cross section, between 14 and 26 MeV of excitation energy. The E1 component shows a bump around 16.5 MeV, associated with the T{sub {lt}} isospin component of the giant dipole resonance. The evaluated strengths associated with the {alpha}{sub 0} decay channel, presented in percentage of the respective energy-weighted sum rules are 0.45(7){percent} for E1, 1.4(3){percent} for E2, and 0.2(1){percent} for E0. {copyright} {ital 1997} {ital The American Physical Society}
A Secular Resonance Between Iapetus and the Giant Planets
Cuk, Matija; Dones, Henry C. Luke; Nesvorny, David; Walsh, Kevin J.
2017-06-01
Iapetus is the outermost of the regular satellites of Saturn, and its origin and evolution present a number of unsolved problems. From the point of view of orbital dynamics, it is remarkable that Iapetus has a large inclination (8 degrees) and a significantly smaller eccentricity (0.03), contrary to the pattern expected if its orbit was excited by encounters between Saturn and other planets early in the Solar System's history (Nesvorny et al, 2014). Here we report our long-term numerical integrations of Iapetus's orbit that show multi-Myr oscillations of Iapetus's eccentricity with an amplitude on the order of 0.01. We find that the basic argument causing this behavior is the sum of the longitude of pericenter and the longitude of the node of Iapetus, with a 0.3 Myr period. This argument appears to be in resonance with the period of the g5 mode in the eccentricity and perihelion of Saturn. We find that our nominal solution, including Saturn's oblateness, Titan, Iapetus and all four giant planets, shows librations of the argument: ǎrpi_Iapetus - ǎrpi_g5 + \\Omega_Iapetus - \\Omega_SaturnEq, where ǎrpi and \\Omega are the longitudes of pericenters and nodes, respectively, and \\Omega_SaturnEq is Saturn's equinox. While planetary perturbations are crucial in generating the g5 mode and therefore maintaining this resonance, we find that Iapetus is affected by the planets only indirectly, with the Sun being the dominant direct perturber. The libration is stable for tens of Myr for the nominal rate of Saturn's pole precession (French et al, 2017), and appears stable indefinitely if we assume a secular resonance between Saturn's node and the secular mode g18 (Ward and Hamilton, 2004; Hamilton and Ward, 2004). We will present the implication of this resonance for the origin of Iapetus's orbit and the dynamical history of Saturn's system. This research is funded by NASA Outer Planets Research Program award NNX14AO38G. References: French, R. G., McGhee-French, C. A
Average radiation widths and the giant dipole resonance width
Arnould, M.; Thielemann, F.K.
1982-11-01
The average E1 radiation width can be calculated in terms of the energy Esub(G) and width GAMMAsub(G) of the Giant Dipole Resonance (GDR). While various models can predict Esub(G) quite reliably, the theoretical situation regarding ..lambda..sub(G) is much less satisfactory. We propose a simple phenomenological model which is able to provide GAMMAsub(G) values in good agreement with experimental data for spherical or deformed intermediate and heavy nuclei. In particular, this model can account for shell effects in GAMMAsub(G), and can be used in conjunction with the droplet model. The GAMMAsub(G) values derived in such a way are used to compute average E1 radiation widths which are quite close to the experimental values. The method proposed for the calculation of GAMMAsub(G) also appears to be well suited when the GDR characteristics of extended sets of nuclei are required, as is namely the case in nuclear astrophysics.
Oberberg, Moritz; Bibinov, Nikita; Ries, Stefan; Awakowicz, Peter; Institute of Electrical Engineering; Plasma Technology Team
2016-09-01
In recently publication, the young diagnostic tool Multipole Resonance Probe (MRP) for electron density measurements was introduced. It is based on active plasma resonance spectroscopy (APRS). The probe was simulated und evaluated for different devices. The geometrical and electrical symmetry simplifies the APRS model, so that the electron density can be easily calculated from the measured resonance. In this work, low pressure nitrogen mixture plasmas with different electron energy distribution functions (EEDF) are investigated. The results of the MRP measurement are compared with measurements of a Langmuir Probe (LP) and Optical Emission Spectroscopy (OES). Probes and OES measure in different regimes of kinetic electron energy. Both probes measure electrons with low kinetic energy (<10 eV), whereas the OES is influenced by electrons with high kinetic energy which are needed for transitions of molecule bands. By the determination of the absolute intensity of N2(C-B) and N2+(B-X)electron temperature and density can be calculated. In a non-maxwellian plasma, all plasma diagnostics need to be combined.
Structure and decay properties of spin-dipole giant resonances within a semimicroscopical approach
Moukhai, EA; Rodin, VA; Urin, MH
1999-01-01
A semimicroscopical approach is applied to calculate: (i) strength functions for the charge-exchange spin-dipole giant resonances in the Pb-208 parent nucleus; (ii) partial and total branching ratios for the direct proton decay of the resonance in Bi-208. The approach is based on continuum-RPA calcu
Modified Multipole Structure for Electron Cyclotron Resonance Ion Sources%对ECR离子源多极磁场结构的改进
P.Suominen; T.Ropponen; H.Koivisto
2007-01-01
Experiments have shown that especially the radial magnetic field component plays a crucial role in the production of highly charged ions with Electron Cyclotron Resonance Ion Sources(ECRIS).However,in several room temperature operating ECRISs the radial magnetic field strength is below the optimum value,mainly due to the limits in permanent magnet technology.Remarkable radial magnetic field improvement can be reached with a relatively simple and cost-effective idea called Modified MultiPole Structure (MMPS).The MMPS differs strongly from the former structures because here the magnetic field is increased only locally without affecting the plasma size.The idea was studied experimentally with a new MMPS plasma chamber prototype.which was designed and constructed for the JYFL 6.4GHz ECRIS.The new chamber is versatile and made it possible to perform several new types of measurements.These showed that the MMPS is especially applicable to increase very high charge-state ion production.Typically the ion current increases more than a factor of 2 in the case of highly charged ions such as Ar16+.
Attosecond delay of xenon $4d$ photoionization at the giant resonance and Cooper minimum
Magrakvelidze, Maia; Chakraborty, Himadri S
2016-01-01
A Kohn-Sham time-dependent local-density-functional scheme is utilized to predict attosecond time delays of xenon 4d photoionization that involves the 4d giant dipole resonance and Cooper minimum. The fundamental effect of electron correlations to uniquely determine the delay at both regions is demonstrated. In particular, for the giant dipole resonance, the delay underpins strong collective effect, emulating the recent prediction at C60 giant plasmon resonance [T. Barillot et al, Phys. Rev. A 91, 033413 (2015)]. For the Cooper minimum, a qualitative similarity with a photorecombination experiment near argon 3p minimum [S. B. Schoun et al, Phys. Rev. Lett. 112, 153001 (2014)] is found. The result should encourage attosecond measurements of Xe 4d photoemission.
Proton decay from the isoscalar giant dipole resonance in Ni-58
Hunyadi, M.; Hashimoto, H.; Li, T.; Akimune, H.; Fujimura, H.; Fujiwara, M.; Gacsi, Z.; Garg, U.; Hara, K.; Harakeh, M. N.; Hoffman, J.; Itoh, M.; Murakami, T.; Nakanishi, K.; Nayak, B. K.; Okumura, S.; Sakaguchi, H.; Terashima, S.; Uchida, M.; Yasuda, Y.; Yosoi, M.
2009-01-01
Proton decay from the 3 (h) over bar omega isoscalar giant dipole resonance (ISGDR) in Ni-58 has been measured using the (alpha, alpha' p) reaction at a bombarding energy of 386 MeV to investigate its decay properties. We have extracted the ISGDR strength under the coincidence condition between inel
Proton decay from the isoscalar giant dipole resonance in 58Ni
Hunyadi, M.; Hashimoto, H.; Li, T.; Akimune, H.; Fujimura, H.; Fujiwara, M.; Gacsi, Z.; Garg, U.; Hara, K.; Harakeh, M. N.; Hoffman, J.; Itoh, M.; Murakami, T.; Nakanishi, K.; Nayak, B. K.; Okumura, S.; Sakaguchi, H.; Terashima, S.; Uchida, M.; Yasuda, Y.; Yosoi, M.
2009-01-01
Proton decay from the 3 (h) over bar omega isoscalar giant dipole resonance (ISGDR) in Ni-58 has been measured using the (alpha, alpha' p) reaction at a bombarding energy of 386 MeV to investigate its decay properties. We have extracted the ISGDR strength under the coincidence condition between inel
Electromagnetic transitions between giant resonances within a continuum-RPA approach
Rodin, VA; Dieperink, AEL
2002-01-01
A general continuum-RPA approach is developed to describe electromagnetic transitions between giant resonances. Using a diagrammatic representation for the three-point Green's function, an expression for the transition amplitude is derived which allows one to incorporate effects of mixing of single
Neutron-skin thickness from the study of the anti-analog giant dipole resonance
Krasznahorkay, A.; Stuhl, L.; Csatlós, M.; Algora, A.; Gulyás, J.; Timár, J.; Paar, N.; Vretenar, D.; Boretzky, K.; Heil, M.; Litvinov, Yu A.; Rossi, D.; Scheidenberger, C.; Simon, H.; Weick, H.; Bracco, A.; Brambilla, S.; Blasi, N.; Camera, F.; Giaz, A.; Million, B.; Pellegri, L.; Riboldi, S.; Wieland, O.; Altstadt, S.; Fonseca, M.; Glorius, J.; Göbel, K.; Heftrich, T.; Koloczek, A.; Kräckmann, S.; Langer, C.; Plag, R.; Pohl, M.; Rastrepina, G.; Reifarth, R.; Schmidt, S.; Sonnabend, K.; Weigand, M.; Harakeh, M. N.; Kalantar-Nayestanaki, N.; Rigollet, C.; Bagchi, S.; Najafi, M. A.; Aumann, T.; Atar, L.; Heine, M.; Holl, M.; Movsesyan, A.; Schrock, P.; Volkov, V.; Wamers, F.; Fiori, E.; Löher, B.; Marganiec, J.; Savran, D.; Johansson, H. T.; Fernández, P. Diaz; Garg, U.; Balabanski, D. L.
2012-01-01
The gamma-decay of the anti-analog of the giant dipole resonance (AGDR) has been measured to the isobaric analog state excited in the p(124Sn,n) reaction at a beam energy of 600 MeV/nucleon. The energy of the transition was also calculated with state-of-the-art self-consistent random-phase approxima
Ono, S., E-mail: tdn01835@st.yamagata-u.ac.j [Graduate School of Science and Engineering, Yamagata University, 4-3-16 Johnan, Yonezawa 992-8510 (Japan); Harada, Y. [Advanced Industrial Science and Technology (AIST), Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki, 305-8568 (Japan); Saito, A.; Lee, J.H.; Kato, T.; Uno, M. [Graduate School of Science and Engineering, Yamagata University, 4-3-16 Johnan, Yonezawa 992-8510 (Japan); Yoshizawa, M. [Graduate School of Engineering, Iwate University, 4-3-5, Ueda, Morioka, Iwate, 020-8551 (Japan); Ohshima, S. [Graduate School of Science and Engineering, Yamagata University, 4-3-16 Johnan, Yonezawa 992-8510 (Japan)
2009-10-15
We designed a 5-GHz miniaturized 8-pole bandpass filter (BPF) using superconducting microstrip quasi-spiral resonators (QSRs) for international mobile telecommunication (IMT)-advanced receiving applications. We used the QSRs with line width and spacing equal to 10 mum for further miniaturization, and investigated a relationship between the structure of the QSR and the unloaded quality factor (Q{sub u}). The Q{sub u} of the optimized QSR of approximately 25,000 was obtained. It was difficult to design a BPF using miniaturized QSRs with high Q{sub u} because of strong cross couplings between QSRs. The lambda{sub g}/8-line inserted inverters were effective in decreasing the unwanted cross couplings. Using these QSR and the lambda{sub g}/8-line inserted inverters, 8-pole cascaded quadruplet (CQ) BPF was designed. We found that it was possible to design a miniaturized BPF with high Q{sub u}.
NATO Advanced Study Institute on Giant Resonances in Atoms, Molecules, and Solids
Esteva, J; Karnatak, R
1987-01-01
Often, a new area of science grows at the confines between recognised subject divisions, drawing upon techniques and intellectual perspectives from a diversity of fields. Such growth can remain unnoticed at first, until a characteristic fami ly of effects, described by appropriate key words, has developed, at which point a distinct subject is born. Such is very much the case with atomic 'giant resonances'. For a start, their name itself was borrowed from the field of nuclear collective resonances. The energy range in which they occur, at the juncture of the extreme UV and the soft X-rays, remains to this day a meeting point of two different experimental techniques: the grating and the crystal spectrometer. The impetus of synchrotron spectroscopy also played a large part in developing novel methods, described by many acronyms, which are used to study 'giant resonances' today. Finally, although we have described them as 'atomic' to differentiate them from their counterparts in Nuclear Physics, their occurrence ...
Coupled-Channel Models of Direct-Semidirect Capture via Giant-Dipole Resonances
Thompson, I J [Lawrence Livermore National Laboratory (LLNL); Escher, Jutta E [ORNL; Arbanas, Goran [ORNL
2013-01-01
Semidirect capture, a two-step process that excites a giant-dipole resonance followed by its radiative de-excitation, is a dominant process near giant-dipole resonances, that is, for incoming neutron energies within 5 20 MeV. At lower energies such processes may affect neutron capture rates that are relevant to astrophysical nucleosynthesis models. We implement a semidirect capture model in the coupled-channel reaction code Fresco and validate it by comparing the cross section for direct-semidirect capture 208Pb(n,g)209Pb to experimental data. We also investigate the effect of low-energy electric dipole strength in the pygmy resonance. We use a conventional single-particle direct-semidirect capture code Cupido for comparison. Furthermore, we present and discuss our results for direct-semidirect capture reaction 130Sn(n,g)131Sn, the cross section of which is known to have a significant effect on nucleosynthesis models.
First principles description of the giant dipole resonance in 16O
Bacca, Sonia; Hagen, Gaute; Orlandini, Giuseppina; Papenbrock, Thomas
2013-01-01
We present an ab-initio calculation of the giant dipole resonance in 16O based on a nucleon-nucleon (NN) interaction from chiral effective field theory that reproduces NN scattering data with high accuracy. By merging the Lorentz integral transform and the coupled-cluster methods, we extend the previous theoretical limits for break-up observables in light nuclei with mass numbers (A<=7), and address the collective giant dipole resonance of 16O. We successfully benchmark the new approach against virtually exact results from the hyper-spherical harmonics method in 4He. Our results for 16O reproduce the position and the total strength (bremsstrahlung sum rule) of the dipole response very well. When compared to the cross section from photo-absorption experiments the theoretical curve exhibits a smeared form of the peak. The tail region between 40 and 100 MeV is reproduced within uncertainties.
Inner-shell photodetachment from N i- : A giant Feshbach resonance
Dumitriu, I.; Bilodeau, R. C.; Gorczyca, T. W.; Walter, C. W.; Gibson, N. D.; Rolles, D.; Pešić, Z. D.; Aguilar, A.; Berrah, N.
2017-08-01
Inner-shell photodetachment from N i-([Ar ] 3 d94 s2) leading to N i+,N i2 + , and N i3 + ion production was studied near and above the 3 p excitation region, in the 60-90 eV photon energy range, using a merged ion-photon beam technique. The absolute photodetachment cross section of N i- leading to N i+ ion production was measured. The 3 p →3 d photoexcitation in N i- gives rise to a giant Feshbach resonance. In the near-threshold region, a Fano profile, modified by a Wigner s -wave (l =0 ) threshold law, accurately fits the N i- single-photodetachment cross section. A lower-order R -matrix calculation shows overall agreement with essential features of the experimental data, confirming the nature of the strong, asymmetric Fano profile of the giant 3 p →3 d photoexcitation-autodetachment resonance in N i- .
Temperature dependence of a spreading width of giant dipole resonance in neutron-rich nuclei
Vdovin, A.I.; Storozhenko, A.N
2003-07-14
A temperature dependence of the spreading width of a giant dipole resonance is studied in the framework of the Quasiparticle-Phonon Model extended to finite temperature using a formalism of the Thermo Field Dynamics. Numerical calculations are performed for {sup 120}Sn and the neutron-rich double-magic isotope {sup 132}Sn It is found that the dispersion of the E1 strength function {sigma} increases with temperature.
Is the Double Giant Dipole Resonance Process Responsible for Alpha Emission in Ternary Fission?
Han, Hong-Yin; Wand, Yi-Hua; Mouze, G.
2001-11-01
The Monte Carlo program built on the double giant dipole resonance model proposed by Mouze et al. [Nuovo Cimento A 110(1997)1097] was employed to calculate the energy spectrum of alpha particles emitted in the spontaneous ternary fission of 252Cf. It has been found that in the case of the zero orbital angular momentum of alpha particles in the alpha decay of the fragments, the measured alpha spectrum can be reproduced approximately by the model without any adjustable parameter.
Is the Double Giant Dipole Resonance Process Responsible for Alpha Emission in Ternary Fission?
HAN Hong-Yin(韩洪银); WAND Yi-Hua(王屹华); G.Mouze
2001-01-01
The Monte Carlo program built on the double giant dipole resonance model proposed by Mouze et al. [Nuovo Cimento A 110(1997)1097] was employed to calculate the energy spectrum of alpha particles emitted in the spontaneous ternary fission of 252Cf. It has been found that in the case of the zero orbital angular momentum of alpha particles in the alpha decay of the fragments, the measured alpha spectrum can be reproduced approximately by the model without any adjustable parameter.
Damping Mechanism of the Giant Dipole Resonance in Hot Nuclei with A=130
Wieland, O.; Bracco, A.; Camera, F.; Benzoni, G.; Blasi, N.; Crespi, F. C. L.; Leoni, S.; Million, B.; Barlini, S.; Kravchuk, V. L.; Gramegna, F.; Lanchais, A.; Maj, A.; Kmiecik, M.; Casini, G.; Chiari, M.; Nannini, A.; Bruno, M.; Geraci, E.
2007-04-01
The gamma decay of the Giant Dipole Resonance (GDR) in 132Ce nuclei has been measured using the reactions 64Ni (Elab= 300, 400, 500 MeV) + 68Zn and 16O (Elab= 130,250 MeV) + 116Sn. The analysis of the data shows clearly that the GDR width increases steadily with temperature at least up to 4 MeV of the temperature. The data can be well interpreted within the thermal shape fluctuation model.
Demekhina, N A; Karapetyan, G S
2001-01-01
The population of the isomeric states is considered in nuclei sup 1 sup 1 sup 5 In and sup 1 sup 8 sup 0 Hf in photonuclear (gamma, gamma') reactions at giant dipole resonance energies. The comparison with the earlier published experimental and theoretical data is made. The behavior of the excitation function gives an evidence for possible increase of the high-spin state population in the giant resonance range
Papakonstantinou, P. [Technische Univ. Darmstadt (Germany). Inst. fuer Kernphysik]|[Athens Univ. (Greece). Physics Dept., Nuclear and Particle Physics Section; Mavrommatis, E. [Athens Univ. (Greece). Physics Dept., Nuclear and Particle Physics Section; Wambach, J.; Ponomarev, V.Y. [Technische Univ. Darmstadt (Germany). Inst. fuer Kernphysik
2004-12-20
We have used a self-consistent Skyrme-Hartree-Fock plus continuum-RPA model to study the low-multipole response of stable and neutron/proton-rich Ni and Sn isotopes. We focus on the momentum-transfer dependence of the strength distribution, as it provides information on the structure of excited nuclear states and in particular on the variations of the transition form factor (TFF) with the energy. Our results show, among other things, that the TFF may show significant energy dependence in the region of the isoscalar giant monopole resonance and that the TFF corresponding to the threshold strength in the case of neutron-rich nuclei is different compared to the one corresponding to the respective giant resonance. Perspectives are given for more detailed future investigations. (orig.)
Li, Yangcheng
2015-01-01
In this dissertation novel resonant propulsion of dielectric microspheres is studied with the goal of sorting spheres with identical resonances, which are critical for developing microspherical photonics. First, evanescent field couplers were developed by fixing tapered microfibers in mechanically robust platforms. The tapers were obtained by chemical etching techniques. Using these platforms, WGMs modal numbers, coupling regimes and quality factors were determined for various spheres and compared with theory. Second, the spectroscopic properties of photonic molecules formed by spheres with better than 0.05% uniformity of WGM resonances were studied. It was shown that various spatial configurations of coupled-cavities present relatively stable mode splitting patterns in the fiber transmission spectra which can be used as spectral signatures to distinguish such photonic molecules. The third part is the study of giant resonant propulsion forces exerted on microspheres. This effect was observed in suspensions of...
Giant second harmonic generation by engineering of double plasmonic resonances at nanoscale
Ren, Ming-Liang; Wang, Ben-Li; Chen, Bao-Qin; Li, Jiafang; Li, Zhi-Yuan
2014-01-01
We have investigated second harmonic generation (SHG) from Ag-coated LiNbO3 (LN) core-shell nanocuboids and found that giant SHG can occur via deliberately designed double plasmonic resonances. By controlling the aspect ratio, we can tune fundamental wave (FW) and SHG signal to match the longitudinal and transverse plasmonic modes simultaneously, and achieve giant enhancement of SHG by more than five orders of magnitude in comparison to a bare LN nanocuboid and by about one order of magnitude to the case adopting only single plasmonic resonance. The underlying key physics is that the double-resonance nanoparticle enables greatly enhanced trapping and harvesting of incident FW energy, efficient internal transfer of optical energy from FW to SHW, and much improved power to transport the SHG energy from the nanoparticle to the far-field region. The proposed double-resonance nanostructure can serve as an efficient subwavelength coherent light source through SHG and enable flexible engineering of light-matter inte...
On the orbital evolution of a pair of giant planets in mean motion resonance
André, Q.; Papaloizou, J. C. B.
2016-10-01
Pairs of extrasolar giant planets in a mean motion commensurability are common with 2:1 resonance occurring most frequently. Disc-planet interaction provides a mechanism for their origin. However, the time-scale on which this could operate in particular cases is unclear. We perform 2D and 3D numerical simulations of pairs of giant planets in a protoplanetary disc as they form and maintain a mean motion commensurability. We consider systems with current parameters similar to those of HD 155358, 24 Sextantis and HD 60532, and disc models of varying mass, decreasing mass corresponding to increasing age. For the lowest mass discs, systems with planets in the Jovian mass range migrate inwards maintaining a 2:1 commensurability. Systems with the inner planet currently at around 1 au from the central star could have originated at a few au and migrated inwards on a time-scale comparable to protoplanetary disc lifetimes. Systems of larger mass planets such as HD 60532 attain 3:1 resonance as observed. For a given mass accretion rate, results are insensitive to the disc model for the range of viscosity prescriptions adopted, there being good agreement between 2D and 3D simulations. However, in a higher mass disc a pair of Jovian mass planets passes through 2:1 resonance before attaining a temporary phase lasting a few thousand orbits in an unstable 5:3 resonance prior to undergoing a scattering. Thus, finding systems in this commensurability is unlikely.
Role of deformation on giant resonances within the QRPA approach and the Gogny force
Peru, S
2008-01-01
Fully consistent axially-symmetric-deformed Quasi-particle Random Phase Approximation (QRPA) calculations have been performed, in which the same Gogny D1S effective force has been used for both the Hartree-Fock-Bogolyubov mean field and the QRPA approaches. Giant resonances calculated in deformed $^{26-28}$Si and $^{22-24}$Mg nuclei as well as in the spherical $^{30}$Si and $^{28}$Mg isotopes are presented. Theoretical results for isovector-dipole and isoscalar monopole, quadrupole, and octupole responses are presented and the impact of the intrinsic nuclear deformation is discussed.
Isoscalar Giant Resonances of 120Sn in the Quasiparticle Relativistic Random Phase Approximation
CAO Li-Gang; MA Zhong-Yu
2004-01-01
@@ The quasiparticle relativistic random phase approximation (QRRPA) is formulated based on the relativistic mean field ground state in the response function formalism. The pairing correlations are taken into account in the Bardeen-Cooper-Schrieffer approximation with a constant pairing gap. The numerical calculations are performed in the case of various isoscalar giant resonances of nucleus 120Sn with parameter set NL3. The calculated results show that the QRRPA approach could satisfactorily reproduce the experimental data of the energies of low-lying states.
Giant field enhancement by funneling effect into sub-wavelength slit-box resonators
Chevalier, Paul; Haidar, Riad; Pardo, Fabrice
2014-01-01
Inspired by the acoustic Helmholtz resonator, we propose a slit-box electromagnetic nanoantenna able to concentrate the energy of an incident beam into surfaces a thousand times smaller than with a classical lens. This design gives birth to giant field intensity enhancement in hot volume, throughout the slit. It reaches $10^4$ in the visible up to $10^8$ in the THz range even with focused beams thanks to an omnidirectional reception. These properties could target applications requiring extreme light concentration, such as SEIRA, non-linear optics and biophotonics.
Neutron-skin thickness from the study of the anti-analog giant dipole resonance
2012-01-01
The gamma-decay of the anti-analog of the giant dipole resonance (AGDR) has been measured to the isobaric analog state excited in the p(124Sn,n) reaction at a beam energy of 600 MeV/nucleon. The energy of the transition was also calculated with state-of-the-art self-consistent random-phase approximation (RPA) and turned out to be very sensitive to the neutron-skin thickness (\\DeltaR_(pn)). By comparing the theoretical results with the measured one, the \\DeltaR_(pn) value for 124Sn was deduced...
Collective multipole excitations based on correlated realistic nucleon-nucleon interactions
Paar, N. [Zagreb Univ. (Croatia). Fac. of Science, Physics Dept.; Papakonstantinou, P.; Hergert, H.; Roth, R. [Technische Univ. Darmstadt (Germany). Inst. fuer Kernphysik
2006-05-24
We investigate collective multipole excitations for closed shell nuclei from {sup 16}O to {sup 208}Pb using correlated realistic nucleon-nucleon interactions in the framework of the random phase approximation (RPA). The dominant short-range central and tensor correlations a re treated explicitly within the Unitary Correlation Operator Method (UCOM), which provides a phase-shift equivalent correlated interaction VUCOM adapted to simple uncorrelated Hilbert spaces. The same unitary transformation that defines the correlated interaction is used to derive correlated transition operators. Using VUCOM we solve the Hartree-Fock problem and employ the single-particle states as starting point for the RPA. By construction, the UCOM-RPA is fully self-consistent, i.e. the same correlated nucleon-nucleon interact ion is used in calculations of the HF ground state and in the residual RPA interaction. Consequently, the spurious state associated with the center-of-mass motion is properly removed and the sum-rules are exhausted within {+-}3%. The UCOM-RPA scheme results in a collective character of giant monopole, dipole, and quadrupole resonances in closed-shell nuclei across the nuclear chart. For the isoscalar giant monopole resonance, the resonance energies are in agreement with experiment hinting at a reasonable compressibility. However, in the 1{sup -} and 2{sup +} channels the resonance energies are overestimated due to missing long-range correlations and three-body contributions. (orig.)
Latina, A
2012-01-01
The electromagnetic radio-frequency (RF) field of accelerating structures and crab-cavities can exhibit transverse field components due to asymmetries in the azimuthal direction of the element geometry. Tracking simulations must be performed to evaluate the impact of such transverse RF deflections on the beam dynamics. In an ultra-relativistic regime where the Panofsky-Wenzel theorem is applicable, these RF deflections can be modeled via a multipolar expansion of the generating RF field similarly to what is done with static magnetic elements. The element implementing such RF multipolar fields has been called RF multipole. In this note we present an analytical formulation of a thin RF multipole Hamiltonian, and we explicitly calculate the RF kick and the elements of its first- and second- order transfer matrices. Also, we present the implementation of the corresponding code in MAD-X, plus some tests of tracking, simplecticity, consistency, and reflected maps that we successfully applied to verify the correctne...
Giant resonances in exotic spherical nuclei within the RPA approach with the Gogny force
P'eru, S; Bortignon, P F
2005-01-01
Theoretical results for giant resonances in the three doubly magic exotic nuclei $^{78}$Ni, $^{100}$Sn and $^{132}$Sn are obtained from Hartree-Fock (HF) plus Random Phase Approximation (RPA) calculations using the D1S parametrization of the Gogny two-body effective interaction. Special attention is paid to full consistency between the HF field and the RPA particle-hole residual interaction. The results for the exotic nuclei, on average, appear similar to those of stable ones, especially for quadrupole and octupole states. More exotic systems have to be studied in order to confirm such a trend. The low energy of the monopole resonance in $^{78}$Ni suggests that the compression modulus in this neutron rich nucleus is lower than the one of stable ones.
The Giant Dipole Resonance built on highly excited states — results of the MEDEA experiment
Suomijärvi, T.; Le Faou, J. H.; Blumenfeld, Y.; Piattelli, P.; Agodi, C.; Alamanos, N.; Alba, R.; Auger, F.; Bellia, G.; Chomaz, Ph.; Coniglione, R.; Del Zoppo, A.; Finocchiaro, P.; Frascaria, N.; Gaardhøje, J. J.; Garron, J. P.; Gillibert, A.; Lamehi-Rachti, M.; Liguori-Neto, R.; Maiolino, C.; Migneco, E.; Russo, G.; Roynette, J. C.; Santonocito, D.; Sapienza, P.; Scarpaci, J. A.; Smerzi, A.
1994-03-01
Gamma-rays, light charged particles and evaporation residues emitted from hot nuclei formed in the 36Ar + 90Zr reaction at 27 MeV/u have been measured with a nearly 4π barium fluoride multidetector. It is shown that hot Sn-like nuclei with a range of excitation energies between 300 and 600 MeV are produced. The γ-ray yield from the decay of the Giant Dipole Resonance in these nuclei is shown to remain constant over this excitation energy range. The measured γ-ray spectra are compared with statistical calculations encompassing several recent theoretical models for the quenching of gamma-ray emission from the dipole resonance at very high temperatures.
On the orbital evolution of a pair of giant planets in mean motion resonance
André, Q
2016-01-01
Pairs of extrasolar giant planets in a mean motion commensurability are common with 2:1 resonance occurring most frequently. Disc-planet interaction provides a mechanism for their origin. However, the time scale on which this could operate in particular cases is unclear. We perform 2D and 3D numerical simulations of pairs of giant planets in a protoplanetary disc as they form and maintain a mean motion commensurability. We consider systems with current parameters similar to those of HD 155358, 24 Sextantis and HD 60532, and disc models of varying mass, decreasing mass corresponding to increasing age. For the lowest mass discs, systems with planets in the Jovian mass range migrate inwards maintaining a 2:1 commensurability. Systems with the inner planet currently at around 1 au from the central star could have originated at a few au and migrated inwards on a time scale comparable to protoplanetary disc lifetimes. Systems of larger mass planets such as HD 60532 attain 3:1 resonance as observed. For a given mass...
Yang, Rui; Zhu, Wenkan; Li, Jingjing
2014-01-27
Giant positive and negative Goos-Hänchen shift more than 5000 times of the operating wavelength is observed when a beam is totally reflected from a substrate decorated by a dielectric grating. Different to the former studies where Goos-Hänchen shift is related to metamaterials or plasmonic materials with ohmic loss, here the giant shift is realized with unity reflectance without the loss. This is extremely advantageous for sensor applications. The Goos-Hänchen shift exhibits a strong resonant feature at the frequency of guided mode resonance, and is associated to the energy flow carried by the guided mode.
Formation and evolution of the two 4/3 resonant giants planets in HD 200946
Santos, M Tadeu dos; Michtchenko, T A; Ferraz-Mello, S
2014-01-01
It has been suggested that HD 200964 is the first exoplanetary system with two Jovian planets evolving in the 4/3 mean- motion resonance. Previous scenarios to simulate the formation of two giant planets in the stable 4/3 resonance configuration have failed. Moreover, the orbital parameters available in the literature point out an unstable configuration of the planetary pair. The purpose of this paper is i) to determine the orbits of the planets from the RV measurements and update the value of the stellar mass (1.57 M), ii) to analyse the stability of the planetary evolution in the vicinity and inside the 4/3 MMR, and iii) to elaborate a possible scenario for the formation of systems in the 4/3 MMR. The results of the formation simulations are able to very closely reproduce the 4/3 resonant dynamics of the best-fit config- uration obtained in this paper. Moreover, the confidence interval of the fit matches well with the very narrow stable region of the 4/3 mean-motion resonance. The formation process of the H...
Resonant bonding driven giant phonon anharmonicity and low thermal conductivity of phosphorene
Qin, Guangzhao; Zhang, Xiaoliang; Yue, Sheng-Ying; Qin, Zhenzhen; Wang, Huimin; Han, Yang; Hu, Ming
2016-10-01
Two-dimensional (2D) phosphorene, which possesses fascinating physical and chemical properties distinctively different from other 2D materials, calls for a fundamental understanding of thermal transport properties for its rapidly growing applications in nano- and optoelectronics and thermoelectrics. However, even the basic phonon property, for example, the exact value of the lattice thermal conductivity (κ ) of phosphorene reported in the literature, can differ unacceptably by one order of magnitude. More importantly, the fundamental physics underlying its unique properties such as strong phonon anharmonicity and unusual anisotropy remains largely unknown. In this paper, based on the analysis of electronic structure and lattice dynamics from first principles, we report that the giant phonon anharmonicity in phosphorene is associated with the soft transverse optical (TO) phonon modes and arises from the long-range interactions driven by the orbital governed resonant bonding. We also provide a microscopic picture connecting the anisotropic and low κ of phosphorene to the giant directional phonon anharmonicity and long-range interactions, which are further traced back to the asymmetric resonant orbital occupations of electrons and characteristics of the hinge-like structure. The unambiguously low κ of phosphorene obtained consistently by three independent ab initio methods confirms the phonon anharmonicity to a large extent and is expected to end the confusing huge deviations in previous studies. This work further pinpoints the necessity of including van der Waals interactions to accurately describe the interatomic interactions in phosphorene. We propose in 2D material that resonant bonding leads to low thermal conductivity, despite that it is originally found in three-dimensional (3D) thermoelectric and phase-change materials. Our study offers insights into phonon transport from the view of orbital states, which would be of great significance to the design of
Hari Bogabathina
2012-01-01
Full Text Available Giant cell myocarditis, but not cardiac sarcoidosis, is known to cause fulminant myocarditis resulting in severe heart failure. However, giant cell myocarditis and cardiac sarcoidosis are pathologically similar, and attempts at pathological differentiation between the two remain difficult. We are presenting a case of fulminant myocarditis that has pathological features suggestive of cardiac sarcoidosis, but clinically mimicking giant cell myocarditis. This patient was treated with cyclosporine and prednisone and recovered well. This case we believe challenges our current understanding of these intertwined conditions. By obtaining a sense of severity of cardiac involvement via delayed hyperenhancement of cardiac magnetic resonance imaging, we were more inclined to treat this patient as giant cell myocarditis with cyclosporine. This resulted in excellent improvement of patient’s cardiac function as shown by delayed hyperenhancement images, early perfusion images, and SSFP videos.
Pygmy and Giant Dipole Resonances by Coulomb Excitation using a Quantum Molecular Dynamics model
Tao, C; Zhang, G Q; Cao, X G; Wang, D Q Fang H W
2012-01-01
Pygmy and Giant Dipole Resonance (PDR and GDR) in Ni isotopes have been investigated by Coulomb excitation in the framework of the Isospin-dependent Quantum Molecular Dynamics model (IQMD). The spectra of $\\gamma$ rays are calculated and the peak energy, the strength and Full Width at Half Maximum (FWHM) of GDR and PDR have been extracted. Their sensitivities to nuclear equation of state, especially to its symmetry energy term are also explored. By a comparison with the other mean-field calculations, we obtain the reasonable values for symmetry energy and its slope parameter at saturation, which gives an important constrain for IQMD model. In addition, we also studied the neutron excess dependence of GDR and PDR parameters for Ni isotopes and found that the energy-weighted sum rule (EWSR) $PDR_{m_1}/GDR_{m_1}%$ increases linearly with the neutron excess.
Roca-Maza, X; Bortignon, P F; Brenna, M; Cao, Li-Gang; Centelles, M; Colò, G; Paar, N; Viñas, X; Vretenar, D; Warda, M
2013-01-01
Experimental and theoretical efforts are being devoted to the study of observables that can shed light on the properties of the nuclear symmetry energy. We present our new results on the excitation energy [X. Roca-Maza et al., Phys. Rev. C 87, 034301 (2013)] and polarizability of the Isovector Giant Quadrupole Resonance (IVGQR), which has been the object of new experimental investigation [S. S. Henshaw et al., Phys. Rev. Lett. 107, 222501 (2011)]. We also present our theoretical analysis on the parity violating asymmetry at the kinematics of the Lead Radius Experiment [S. Abrahamyan et al. (PREx Collaboration), Phys. Rev. Lett. 108, 112502 (2012)] and highlight its relation with the density dependence of the symmetry energy [X. Roca-Maza et al., Phys. Rev. Lett. 106, 252501 (2011)].
Measurement of isospin mixing at a finite temperature in 80Zr via giant dipole resonance decay
Corsi, A.; Wieland, O.; Barlini, S.; Bracco, A.; Camera, F.; Kravchuk, V. L.; Baiocco, G.; Bardelli, L.; Benzoni, G.; Bini, M.; Blasi, N.; Brambilla, S.; Bruno, M.; Casini, G.; Ciemala, M.; Cinausero, M.; Crespi, F. C. L.; D'Agostino, M.; Degerlier, M.; Giaz, A.; Gramegna, F.; Kmiecik, M.; Leoni, S.; Maj, A.; Marchi, T.; Mazurek, K.; Meczynski, W.; Million, B.; Montanari, D.; Morelli, L.; Myalski, S.; Nannini, A.; Nicolini, R.; Pasquali, G.; Poggi, G.; Vandone, V.; Vannini, G.
2011-10-01
Isospin mixing in the hot compound nucleus 80Zr was studied by measuring and comparing the γ-ray emission from the fusion reactions 40Ca+40Ca at Ebeam=200 MeV and 37Cl+44Ca at Ebeam=153 MeV. The γ yield associated with the giant dipole resonance is found to be different in the two reactions because, in self-conjugate nuclei, the E1 selection rules forbid the decay between states with isospin I=0. The degree of mixing is deduced from statistical-model analysis of the γ-ray spectrum emitted by the compound nucleus 80Zr with the standard parameters deduced from the γ decay of the nucleus 81Rb. The results are used to deduce the zero-temperature value, which is then compared with the latest predictions. The Coulomb spreading width is found to be independent of temperature.
Finite amplitude method applied to giant dipole resonance in heavy rare-earth nuclei
Oishi, Tomohiro; Hinohara, Nobuo
2016-01-01
Background: The quasiparticle random phase approximation (QRPA), within the framework of the nuclear density functional theory (DFT), has been a standard tool to access the collective excitations of the atomic nuclei. Recently, finite amplitude method (FAM) has been developed, in order to perform the QRPA calculations efficiently without any truncation on the two-quasiparticle model space. Purpose: We discuss the nuclear giant dipole resonance (GDR) in heavy rare-earth isotopes, for which the conventional matrix diagonalization of the QRPA is numerically demanding. A role of the Thomas-Reiche-Kuhn (TRK) sum rule enhancement factor, connected to the isovector effective mass, is also investigated. Methods: The electric dipole photoabsorption cross section was calculated within a parallelized FAM-QRPA scheme. We employed the Skyrme energy density functional self-consistently in the DFT calculation for the ground states and FAM-QRPA calculation for the excitations. Results: The mean GDR frequency and width are mo...
Multineutron photodisintegration of the {sup 197}Au nucleus behind the giant dipole resonance
Ermakov, A. N.; Ishkhanov, B. S.; Kapitonov, I. M.; Htun, Kyaw Kyaw; Makarenko, I. V.; Orlin, V. N.; Shvedunov, V. I. [Moscow State University, Institute of Nuclear Physics (Russian Federation)
2008-03-15
An experiment in which the gold isotope {sup 197}Au was irradiated with a beam of bremsstrahlung photons having an endpoint energy of E{sub {gamma}}{sup m} = 67.7 MeV and originating from the RTM-70 racetrack microtron of the Institute of Nuclear Physics at Moscow State University was performed. The gammaray spectra of the residual beta activity of an irradiated sample were measured. Multinucleon photonuclear reactions on {sup 197}Au nuclei were observed in the experiment. Photonuclear reactions on a {sup 197}Au nucleus that involve the emission of up to seven neutrons were recorded for the first time. The experimental results in question suggest the important role of the quasideuteron photodisintegration mechanism in the energy region behind the giant dipole resonance.
Multineutron photodisintegration of the 197Au nucleus behind the giant dipole resonance
Ermakov, A. N.; Ishkhanov, B. S.; Kapitonov, I. M.; Htun, Kyaw Kyaw; Makarenko, I. V.; Orlin, V. N.; Shvedunov, V. I.
2008-03-01
An experiment in which the gold isotope 197Au was irradiated with a beam of bremsstrahlung photons having an endpoint energy of E {/γ m } = 67.7 MeV and originating from the RTM-70 racetrack microtron of the Institute of Nuclear Physics at Moscow State University was performed. The gammaray spectra of the residual beta activity of an irradiated sample were measured. Multinucleon photonuclear reactions on 197Au nuclei were observed in the experiment. Photonuclear reactions on a 197Au nucleus that involve the emission of up to seven neutrons were recorded for the first time. The experimental results in question suggest the important role of the quasideuteron photodisintegration mechanism in the energy region behind the giant dipole resonance.
He, W B; Cao, X G; Cai, X Z; Zhang, G Q
2014-01-01
It is studied how the $\\alpha$ cluster degrees of freedom, such as $\\alpha$ clustering configurations close to the $\\alpha$ decay threshold in $^{12}$C and $^{16}$O, including the linear chain, triangle, square, kite, and tetrahedron, affect nuclear collective vibrations with a microscopic dynamical approach, which can describe properties of nuclear ground states well across the nuclide chart and reproduce the standard giant dipole resonance (GDR) of $^{16}$O quite nicely. It is found that the GDR spectrum is highly fragmented into several apparent peaks due to the $\\alpha$ structure. The different $\\alpha$ cluster configurations in $^{12}$C and $^{16}$O have corresponding characteristic spectra of GDR. The number and centroid energies of peaks in the GDR spectra can be reasonably explained by the geometrical and dynamical symmetries of $\\alpha$ clustering configurations. Therefore, the GDR can be regarded as a very effective probe to diagnose the different $\\alpha$ cluster configurations in light nuclei.
Origin of fine structure of the giant dipole resonance in sd-shell nuclei
Fearick, R W; Matsubara, H; von Neumann-Cosel, P; Richter, A; Roth, R; Tamii, A
2014-01-01
A set of high resolution zero-degree inelastic proton scattering data on 24Mg, 28Si, 32S, and 40Ca provides new insight into the long-standing puzzle of the origin of fragmentation of the Giant Dipole Resonance (GDR) in sd-shell nuclei. Understanding is provided by state-of-the-art theoretical Random Phase Approximation (RPA) calculatios for deformed nuclei using for the first time a realistic nucleon-nucleon interaction derived from the Argonne V18 potential with the unitary correlation operator method and supplemented by a phenomenological three-nucleon contact interaction. A wavelet analysis allows to extract significant scales both in the data and calculations characterizing the fine structure of the GDR. The fair agreement supports that the fine structure arises from ground-state deformation driven by alpha clustering.
Neutron-skin thickness from the study of the anti-analog giant dipole resonance
Krasznahorkay, A.; Stuhl, L.; Csatlós, M.; Algora, A.; Gulyás, J.; Timár, J.; Paar, N.; Vretenar, D.; Harakeh, M. N.; Boretzky, K.; Heil, M.; Litvinov, Yu. A.; Rossi, D.; Scheidenberger, C.; Simon, H.; Weick, H.; Bracco, A.; Brambilla, S.; Blasi, N.; Camera, F.; Giaz, A.; Million, B.; Pellegri, L.; Riboldi, S.; Wieland, O.; Altstadt, S.; Fonseca, M.; Glorius, J.; Göbel, K.; Heftrich, T.; Koloczek, A.; Kräckmann, S.; Langer, C.; Plag, R.; Pohl, M.; Rastrepina, G.; Reifarth, R.; Schmidt, S.; Sonnabend, K.; Weigand, M.; Kalantar-Nayestanaki, N.; Rigollet, C.; Bagchi, S.; Najafi, M. A.; Aumann, T.; Atar, L.; Heine, M.; Holl, M.; Movsesyan, A.; Schrock, P.; Volkov, V.; Wamers, F.; Fiori, E.; Löher, B.; Marganiec, J.; Savran, D.; Johansson, H. T.; Fernández, P. Diaz; Garg, U.; Balabanski, D. L.
2012-10-01
The γ-decay of the anti-analog of the giant dipole resonance (AGDR) to the isobaric analog state has been measured following the p(124Sn,n) reaction at a beam energy of 600 MeV/nucleon. The energy of the transition was also calculated with state-of-the-art self-consistent relativistic random-phase approximation (RPA) and turned out to be very sensitive to the neutronskin thickness (ΔRpn). By comparing the theoretical results with the measured one, the ΔRpn value for 124Sn was deduced to be 0.21 ± 0.07 fm, which agrees well with the previous results. The present method offers new possibilities for measuring the neutron-skin thicknesses of very exotic isotopes.
Kumar, A K Rhine; Dang, N Dinh
2015-01-01
Apart from the higher limits of isospin and temperature, the properties of atomic nuclei are intriguing and less explored at the limits of lowest but finite temperatures. At very low temperatures there is a strong interplay between the shell (quantal fluctuations), statistical (thermal fluctuations), and residual pairing effects as evidenced from the studies on giant dipole resonance (GDR). In our recent work [Phys. Rev. C \\textbf{90}, 044308 (2014)], we have outlined some of our results from a theoretical approach for such warm nuclei where all these effects are incorporated along within the thermal shape fluctuation model (TSFM) extended to include the fluctuations in the pairing field. In this article, we present the complete formalism based on the microscopic-macroscopic approach for determining the deformation energies and a macroscopic approach which links the deformation to GDR observables. We discuss our results for the nuclei $^{97}$Tc, $^{120}$Sn, $^{179}$Au, and $^{208}$Pb, and corroborate with the...
Monopole giant resonance in $^{100-132}$Sn, $^{144}$Sm and $^{208}$Pb
Kvasil, J; Repko, A; Reinhard, P -G; Nesterenko, V O; Kleinig, W
2014-01-01
The isoscalar giant monopole resonance (GMR) in spherical nuclei $^{100-132}$Sn, $^{144}$Sm, and $^{208}$Pb is investigated within the Skyrme random-phase-approximation (RPA) for a variety of Skyrme forces and different pairing options. The calculated GMR strength functions are directly compared to the available experimental distributions. It is shown that, in accordance to results of other groups, description of GMR in Sn and heavier Sm/Pb nuclei needs different values of the nuclear incompressibilty, $K \\approx$ 200 or 230 MeV, respectively. Thus none from the used Skyrme forces is able to describe GMR in these nuclei simultaneously. The GMR peak energy in open-shell $^{120}$Sn is found to depend on the isoscalar effective mass, which might be partly used for a solution of the above problem. Some important aspects of the problem (discrepancies of available experimental data, proper treatment of the volume and surface compression in finite nuclei, etc) are briefly discussed.
Measurement of Giant Dipole Resonance width at low temperature: A new experimental perspective
Mukhopadhyay, S; Pal, Surajit; Bhattacharya, Srijit; De, A; Bhattacharya, S; Bhattacharya, C; Banerjee, K; Kundu, S; Rana, T K; Mukherjee, G; Pandey, R; Gohil, M; Pai, H; Meena, J K; Banerjee, S R
2011-01-01
The systematic evolution of the giant dipole resonance (GDR) width in the temperature region of 0.9 ~ 1.4 MeV has been measured experimentally for 119Sb using alpha induced fusion reaction and employing the LAMBDA high energy photon spectrometer. The temperatures have been precisely determined by simultaneously extracting the vital level density parameter from the neutron evaporation spectrum and the angular momentum from gamma multiplicity filter using a realistic approach. The systematic trend of the data seems to disagree with the thermal shape fluctuation model (TSFM). The model predicts the gradual increase of GDR width from its ground state value for T > 0 MeV whereas the measured GDR widths appear to remain constant at the ground state value till T ~ 1 MeV and increase thereafter indicating towards a failure of the adiabatic assumption of the model at low temperature.
Extremely narrow resonances, giant sensitivity and field enhancement in low-loss waveguide sensors
Nesterenko, D. V.; Hayashi, S.; Sekkat, Z.
2016-06-01
Low-loss waveguides (WGs), which support excitation of waveguide modes (WMs), are based on a dielectric WG separated from an absorptive film by a low-index dielectric spacer layer. We perform numerical and analytical study of the impact of the losses imposed to the WG in a planar sensing structure in the Kretschmann configuration on the resonance properties of the excitation. We demonstrate that the loss degree of the WMs can be controlled by the thickness of the spacer layer for both s and p polarizations. Extremely narrow resonances are discovered in the reflectivity spectra due to excitation of the low-loss WMs, and the maximum of the estimated sensitivity by intensity is found to be of 105-fold higher as compared to the conventional surface plasmon and WG-coupled surface plasmon sensors. We reveal the giant field intensity enhancement of 107-fold on the surface of the sensing structure in aqueous sensing media that can provide stronger fluorescence intensity at lower sample volumes for fluorescent labeling sensing.
Kvasil, J; Repko, A; Kleinig, W; Reinhard, P -G
2016-01-01
The deformation-induced splitting of isoscalar giant monopole resonance (ISGMR) is systematically analyzed in a wide range of masses covering medium, rare-earth, actinide, and superheavy axial deformed nuclei. The study is performed within the fully self-consistent quasiparticle random-phase-approximation (QRPA) method based on the Skyrme functional. Two Skyrme forces, one with a large (SV-bas) and one with a small (SkP) nuclear incompressibility, are considered. The calculations confirm earlier results that, due to the deformation-induced E0-E2 coupling, the isoscalar E0 resonance attains a double-peak structure and significant energy upshift. Our results are compared with available analytic estimations. Unlike earlier studies, we get a smaller energy difference between the lower and upper peaks and thus a stronger E0-E2 coupling. This in turn results in more pumping of E0 strength into the lower peak and more pronounced splitting of ISGMR. We also discuss widths of the peaks and their negligible correlation...
Multipole Expansion in Generalized Electrodynamics
Bonin, C A; Ortega, P H
2016-01-01
In this article we study some classical aspects of Podolsky Electrodynamics in the static regime. We develop the multipole expansion for the theory in both the electrostatic and the magnetostatic cases. We also address the problem of consistently truncating the infinite series associated with the several kinds of multipoles, yielding approximations for the static Podolskian electromagnetic field to any degree of precision required. Moreover, we apply the general theory of multipole expansion to some specific physical problems. In those problems we identify the first terms of the series with the monopole, dipole and quadrupole terms in the generalized theory. We also propose a situation in which Podolsky theory can be experimentally tested.
On the dynamic toroidal multipoles
Fernandez-Corbaton, Ivan; Rockstuhl, Carsten
2015-01-01
Toroidal multipoles are attracting research attention, particularly in the field of metamaterials. They are often understood as a multipolar family in its own right. The dynamic toroidal multipoles emerge from the separation of one of the two transverse multipoles into two parts, referred to as electric and toroidal. Here, we establish that the dynamic toroidal multipolar components of an electric current distribution cannot be determined by measuring the radiation from the source or its coupling to external electromagnetic waves. We analytically show how the split into electric and toroidal parts causes the appearance of non-radiative components in each of the two parts, which cancel when summed back together. The toroidal multipoles do not have an independent meaning with respect to their interaction with the radiation field. Their formal meaning is clear, however. They are the higher order terms of an expansion of the multipolar coefficients of electric parity with respect to the electromagnetic size of th...
Multipole structure of compact objects
Quevedo, Hernando
2016-01-01
We analyze the applications of general relativity in relativistic astrophysics in order to solve the problem of describing the geometric and physical properties of the interior and exterior gravitational and electromagnetic fields of compact objects. We focus on the interpretation of exact solutions of Einstein's equations in terms of their multipole moments structure. In view of the lack of physical interior solutions, we propose an alternative approach in which higher multipoles should be taken into account.
Using the (p-arrow-right,p-arrow-right ') reaction to study. delta. S = 0 giant resonances
Baker, F.T.; Bimbot, L.; Fergerson, R.W.; Glashausser, C.; Jones, K.; Green, A.; Nakayama, K.; Nanda, S.
1988-03-01
Measurements of spin-flip probabilities for inelastic scattering of 318 MeV protons from /sup 40/Ca reveal that much of the background underlying the giant dipole and quadrupole resonances at small angles is from ..delta..S = 1 transitions. This holds the promise of allowing a much better estimate of this background than has previously been possible;one model-dependent parameter is necessary. Subsequent analysis with a first estimate of this parameter is presented
TERRESTRIAL PLANET FORMATION DURING THE MIGRATION AND RESONANCE CROSSINGS OF THE GIANT PLANETS
Lykawka, Patryk Sofia [Astronomy Group, Faculty of Social and Natural Sciences, Kinki University, Shinkamikosaka 228-3, Higashiosaka-shi, Osaka 577-0813 (Japan); Ito, Takashi, E-mail: patryksan@gmail.com [National Astronomical Observatory of Japan, Osawa 2-21-1, Mitaka, Tokyo 181-8588 (Japan)
2013-08-10
The newly formed giant planets may have migrated and crossed a number of mutual mean motion resonances (MMRs) when smaller objects (embryos) were accreting to form the terrestrial planets in the planetesimal disk. We investigated the effects of the planetesimal-driven migration of Jupiter and Saturn, and the influence of their mutual 1:2 MMR crossing on terrestrial planet formation for the first time, by performing N-body simulations. These simulations considered distinct timescales of MMR crossing and planet migration. In total, 68 high-resolution simulation runs using 2000 disk planetesimals were performed, which was a significant improvement on previously published results. Even when the effects of the 1:2 MMR crossing and planet migration were included in the system, Venus and Earth analogs (considering both orbits and masses) successfully formed in several runs. In addition, we found that the orbits of planetesimals beyond a {approx} 1.5-2 AU were dynamically depleted by the strengthened sweeping secular resonances associated with Jupiter's and Saturn's more eccentric orbits (relative to the present day) during planet migration. However, this depletion did not prevent the formation of massive Mars analogs (planets with more than 1.5 times Mars's mass). Although late MMR crossings (at t > 30 Myr) could remove such planets, Mars-like small mass planets survived on overly excited orbits (high e and/or i), or were completely lost in these systems. We conclude that the orbital migration and crossing of the mutual 1:2 MMR of Jupiter and Saturn are unlikely to provide suitable orbital conditions for the formation of solar system terrestrial planets. This suggests that to explain Mars's small mass and the absence of other planets between Mars and Jupiter, the outer asteroid belt must have suffered a severe depletion due to interactions with Jupiter/Saturn, or by an alternative mechanism (e.g., rogue super-Earths)
Temperature dependence of the giant dipole resonance width in 152Gd
Ghosh, C.; Mishra, G.; Rhine Kumar, A. K.; Dokania, N.; Nanal, V.; Pillay, R. G.; Kumar, Suresh; Rout, P. C.; Joshi, Sandeep; Arumugam, P.
2016-07-01
To investigate the dependence of giant dipole resonance (GDR) width on temperature (T ) and angular momentum (J ), high energy γ -ray spectra were measured in the reaction 28Si+124Sn at E28Si=135 MeV. The J information was deduced from multiplicity of low-energy γ rays. The GDR parameters, namely, the centroid energy and width are extracted using statistical model analysis. The observed variation of the GDR width for T ˜1.2 -1.37 MeV and J ˜20 ℏ -40 ℏ is consistent with the universal scaling given by Kusnezov et al., which is applicable in the liquid-drop regime. The GDR input cross sections extracted from the statistical model best fits are compared with thermal shape fluctuation model (TSFM) calculations and are found to be in good agreement. The TSFM calculations predominantly favor the noncollective oblate shape, while the statistical model fit with both prolate and oblate shapes describes the data. The present data together with earlier measurements indicate a very slow variation of the GDR width for T ˜1.2 to 1.5 MeV. The observed trend is well explained by the TSFM calculations, although the calculated values are ˜4 %-13% higher than the data.
Tao, C; Zhang, G Q; Cao, X G; Fang, D Q; Wang, H W; Xu, J
2013-01-01
The isoscalar giant monopole resonance (ISGMR) in Sn isotopes and other nuclei has been investigated by Coulomb excitations in the framework of the isospin-dependent quantum molecular dynamics (IQMD) model. The spectrum of GMR has been calculated by taking the root-mean-square (RMS) radius of a nucleus as its monopole moment. The peak energy, the full width at half maximum (FWHM), and the strength of GMR extracted by a Gaussian fit to the spectrum have been studied. The GMR peak energies for Sn isotopes from the calculations using a mass-number dependent Gaussian wave-packet width $\\sigma_r$ for nucleons are found to be overestimated and show a weak dependence on the mass number compared with the experimental data. However, it has been found that experimental data of the GMR peak energies for $^{40}$Ca, $^{56}$Ni, $^{90}$Zr and $^{208}$Pb as well as Sn isotopes can be nicely reproduced after taking into account the isospin dependence in isotope chains in addition to the mass number dependence of $\\sigma_r$ fo...
Giant exciton Fano resonance in quasi-one-dimensional Ta2NiSe5
Larkin, T. I.; Yaresko, A. N.; Pröpper, D.; Kikoin, K. A.; Lu, Y. F.; Takayama, T.; Mathis, Y.-L.; Rost, A. W.; Takagi, H.; Keimer, B.; Boris, A. V.
2017-05-01
We report the complex dielectric function of the quasi-one-dimensional chalcogenide Ta2NiSe5 , which undergoes a structural phase transition presumably associated with exciton condensation below Tc=326 K [Y. Wakisaka et al., Phys. Rev. Lett. 103, 026402 (2009), 10.1103/PhysRevLett.103.026402; Y. F. Lu et al., Nat. Commun. 8, 14408 (2017), 10.1038/ncomms14408], and of the isostructural Ta2NiS5 , which does not exhibit such a transition. Using spectroscopic ellipsometry, we have detected exciton doublets with pronounced Fano line shapes in both the compounds. The exciton Fano resonances in Ta2NiSe5 display an order-of-magnitude higher intensity than those in Ta2NiS5 . In conjunction with prior theoretical work [E. Rashba, Sov. Phys. Semicond. 8, 807 (1975)], we attribute this observation to the giant oscillator strength of spatially extended exciton-phonon bound states in Ta2NiSe5 . The formation of exciton-phonon complexes in Ta2NiS5 and Ta2NiSe5 is confirmed by the pronounced temperature dependence of sharp interband transitions in the optical spectra, the peak energies and widths of which scale with the thermal population of optical phonon modes. The description of the optically excited states in terms of strongly overlapping exciton complexes is in good agreement with the hypothesis of an exciton insulator ground state.
Experimental study of the isovector giant dipole resonance in 80Zr and 81Rb
Ceruti, S.; Camera, F.; Bracco, A.; Mentana, A.; Avigo, R.; Benzoni, G.; Blasi, N.; Bocchi, G.; Bottoni, S.; Brambilla, S.; Crespi, F. C. L.; Giaz, A.; Leoni, S.; Million, B.; Morales, A. I.; Nicolini, R.; Pellegri, L.; Riboldi, S.; Wieland, O.; Bazzacco, D.; Ciemala, M.; Farnea, E.; Gottardo, A.; Kmiecik, M.; Maj, A.; Mengoni, D.; Michelagnoli, C.; Modamio, V.; Montanari, D.; Napoli, D.; Recchia, F.; Sahin, E.; Ur, C.; Valiente-Dobón, J. J.; Wasilewska, B.; Zieblinski, M.
2017-01-01
The isovector giant dipole resonance (IVGDR) γ decay was measured in the compound nuclei 80Zr and 81Rb at an excitation energy of E*=54 MeV. The fusion reaction 40Ca+40Ca at Ebeam=136 MeV was used to form the compound nucleus 80Zr, while the reaction 37Cl+44Ca at Ebeam=95 MeV was used to form the compound nucleus 81Rb at the same excitation energy. The IVGDR parameters extracted from the analysis were compared with the ones found at higher excitation energy (E*=83 MeV). The comparison allows one to observe two different nuclear mechanisms: (i) the IVGDR intrinsic width remains constant with the excitation energy in the nucleus 81Rb; (ii) the isospin-violating spreading width (i.e., Coulomb spreading width) remains constant with the excitation energy in the nucleus 80Zr. The experimental setup used for the γ -ray detection was composed by the AGATA demonstrator array coupled to the large-volume LaBr3:Ce detectors of the HECTOR+ array.
Signature of clustering in quantum many-body systems probed by the giant dipole resonance
Pandit, Deepak; Mondal, Debasish; Dey, Balaram; Bhattacharya, Srijit; Mukhopadhyay, S.; Pal, Surajit; De, A.; Banerjee, S. R.
2017-03-01
The present experimental study illustrates how large deformations attained by nuclei due to cluster formation are perceived through the giant dipole resonance (GDR) strength function. The high energy GDR γ rays have been measured from 32S at different angular momenta (J ) but similar temperatures in the reactions 4He(Elab=45 MeV )+28Si and 20Ne(Elab=145 MeV )+12C . The experimental data at lower J (˜10 ℏ ) suggests a normal deformation, similar to the ground state value, showing no potential signature of clustering. However, it is found that the GDR lineshape is fragmented into two prominent peaks at high J (˜20 ℏ ) providing a direct measurement of the large deformation developed in the nucleus. The observed lineshape is also completely different from the ones seen for Jacobi shape transition at high J pointing towards the formation of cluster structure in superdeformed states of 32S at such high spin. Thus, the GDR can be regarded as a unique tool to study cluster formation at high excitation energies and angular momenta.
Quenching of the Giant Dipole Resonance Strength at High Excitation Energy
Santonocito, D. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, I-95123 Catania (Italy); Blumenfeld, Y. [Institut de Physique Nucleaire, IN2P3-CNRS, F-91406 Orsay (France); Agodi, C. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, I-95123 Catania (Italy); Alba, R. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, I-95123 Catania (Italy); Bellia, G. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, I-95123 Catania (Italy); Dipartimento di Fisica e Astronomia dell' Universita di Catania, via S. Sofia 64, I-95123 Catania (Italy); Coniglione, R. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, I-95123 Catania (Italy); Delaunay, F. [Institut de Physique Nucleaire, IN2P3-CNRS, F-91406 Orsay (France); Del Zoppo, A. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, I-95123 Catania (Italy); Finocchiaro, P. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, I-95123 Catania (Italy); Frascaria, N. [Institut de Physique Nucleaire, IN2P3-CNRS, F-91406 Orsay (France); Hongmei, F. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, I-95123 Catania (Italy); Lima, V. [Institut de Physique Nucleaire, IN2P3-CNRS, F-91406 Orsay (France); Maiolino, C. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, I-95123 Catania (Italy); Migneco, E. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, I-95123 Catania (Italy); Dipartimento di Fisica e Astronomia dell' Universita di Catania, via S. Sofia 64, I-95123 Catania (Italy); Piattelli, P. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, I-95123 Catania (Italy); Sapienza, P. [INFN - Laboratori Nazionali del Sud, via S. Sofia 62, I-95123 Catania (Italy); Scarpaci, J.A. [Institut de Physique Nucleaire, IN2P3-CNRS, F-91406 Orsay (France)
2007-05-15
The evolution with excitation energy of the Giant Dipole Resonance features in nuclei of mass A{approx}108-136 is reviewed. We first discuss the results of the experiments performed with MEDEA studying the GDR gamma decay from hot nuclei populated at excitation energies above 300 MeV. The focus of the paper is on the excitation energy region between 160 and 290 MeV. This region has been investigated through the study of the reactions {sup 116}Sn + {sup 12}C at 17 and 23A MeV, and {sup 116}Sn + {sup 24}Mg at 17A MeV. Gamma-rays were detected using MEDEA in coincidence with evaporation residues detected in MACISTE. The analysis of the gamma-ray spectra and their comparison with statistical calculations are presented. The comparison with {gamma}-ray spectra from the reaction {sup 36}Ar + {sup 98}Mo at higher excitation energies shows a coherent scenario where a progressive reduction of {gamma} multiplicity relative to predictions for 100% of the Energy Weighted Sum Rule is observed above 200 MeV excitation energy. Finally, the existence of a link between disappearance of collective motion and the liquid-gas phase transitions is discussed.
Thermal shape fluctuation model study of the giant dipole resonance in $^{152}$Gd
Kumar, A K Rhine
2015-01-01
We have studied the giant dipole resonance (GDR) in the hot and rotating nucleus $^{152}$Gd within the framework of thermal shape fluctuation model (TSFM) built on the microscopic-macroscopic calculations of the free energies with a macroscopic approach for the GDR. Our results for GDR cross sections are in good agreement with the experimental values except for a component peaking around 17 MeV where the data has large uncertainties. Such a component is beyond our description which properly takes care of the splitting of GDR components due to the deformation and Coriolis effects. Around this 17 MeV lies the half maximum in experimental cross sections, and hence the extracted GDR widths and deformations (estimated from these widths) turn out to be overestimated and less reliable. Reproducing these widths with empirical formulae could conceal the information contained in the cross sections. Fully microscopic GDR calculations and a more careful look at the data could be useful to understand the GDR component aro...
Microscopic Study of the Isoscalar Giant Monopole Resonance in Cd, Sn and Pb Isotopes
Cao, Li-Gang; Colo, G
2012-01-01
The isoscalar giant monopole resonance (ISGMR) in Cd, Sn and Pb isotopes has been studied within the self-consistent Skyrme Hartree-Fock+BCS and quasi-particle random phase approximation (QRPA). Three Skyrme parameter sets are used in the calculations, i.e., SLy5, SkM* and SkP, since they are characterized by different values of the compression modulus in symmetric nuclear matter, namely K=230, 217, and 202 MeV, respectively. We also investigate the effect of different types of pairing forces on the ISGMR in Cd, Sn and Pb isotopes. The calculated peak energies and the strength distributions of ISGMR are compared with available experimental data. We find that SkP fails completely to describe the ISGMR strength distribution for all isotopes due to its low value of the nuclear matter incompressibility, namely K=202 MeV. On the other hand, the SLy5 parameter set, supplemented by an appropriate pairing interaction, gives a reasonable description of the ISGMR in Cd and Pb isotopes. A better description of ISGMR in ...
Neutron-skin thickness from the study of the antianalog giant dipole resonance
Krasznahorkay, A; Csatlós, M; Algora, A; Gulyás, J; Timár, J; Paar, N; Vretenar, D; Boretzky, K; Heil, M; Litvinov, Yu A; Rossi, D; Scheidenberger, C; Simon, H; Weick, H; Bracco, A; Brambilla, S; Blasi, N; Camera, F; Giaz, A; Million, B; Pellegri, L; Riboldi, S; Wieland, O; Altstadt, S; Fonseca, M; Glorius, J; Göbel, K; Heftrich, T; Koloczek, A; Kräckmann, S; Langer, C; Plag, R; Pohl, M; Rastrepina, G; Reifarth, R; Schmidt, S; Sonnabend, K; Weigand, M; Harakeh, M N; Kalantar-Nayestanaki, N; Rigollet, C; Bagchi, S; Najafi, M A; Aumann, T; Atar, L; Heine, M; Holl, M; Movsesyan, A; Schrock, P; Volkov, V; Wamers, F; Fiori, E; Löher, B; Marganiec, J; Savaran, D; Johansson, H T; Fernández, P Diaz; Garg, U; Balabanski, D L
2012-01-01
The gamma-decay of the anti-analog of the giant dipole resonance (AGDR) has been measured to the isobaric analog state excited in the p(124Sn,n) reaction at a beam energy of 600 MeV/nucleon. The energy of the transition was also calculated with state-of-the-art self-consistent random-phase approximation (RPA) and turned out to be very sensitive to the neutron-skin thickness (\\DeltaR_(pn)). By comparing the theoretical results with the measured one, the \\DeltaR_(pn) value for 124Sn was deduced to be 0.18 \\pm 0.02 fm, which agrees well with the previous results. The energy of the AGDR measured previously for ^(208)Pb was also used to determine the \\DeltaR_(pn) for ^(208)Pb. In this way a very precise \\DeltaR_(pn) = 0.18 \\pm 0.02 neutron-skin thickness has been obtained for 208Pb. The present method offers new possibilities for measuring the neutron-skin thicknesses of very exotic isotopes.
Borg, Klaas van der
1979-01-01
Dit proefschrift beschrijft de verdeling van isoscalar multipoolsterkte in 24,26Mg, 28Si en 40Ca gemeten met behulp van inelastische verstrooing van alphadeeltjes met een energie van 120 MeV. ... Zie: Samenvatting
Radiation reaction of multipole moments
Kazinski, P. O.
2007-08-01
A Poincaré-invariant description is proposed for the effective dynamics of a localized system of charged particles in classical electrodynamics in terms of the intrinsic multipole moments of the system. A relativistic-invariant definition for the intrinsic multipole moments of a system of charged particles is given. A new generally covariant action functional for a relativistic perfect fluid is proposed. In the case of relativistic charged dust, it is proven that the description of the problem of radiation reaction of multipole moments by the model of particles is equivalent to the description of this problem by a hydrodynamic model. An effective model is obtained for a pointlike neutral system of charged particles that possesses an intrinsic dipole moment, and the free dynamics of this system is described. The bound momentum of a point dipole is found.
Radiation reaction for multipole moments
Kazinski, P O
2006-01-01
We propose a Poincare-invariant description for the effective dynamics of systems of charged particles by means of intrinsic multipole moments. To achieve this goal we study the effective dynamics of such systems within two frameworks -- the particle itself and hydrodynamical one. We give a relativistic-invariant definition for the intrinsic multipole moments both pointlike and extended relativistic objects. Within the hydrodynamical framework we suggest a covariant action functional for a perfect fluid with pressure. In the case of a relativistic charged dust we prove the equivalence of the particle approach to the hydrodynamical one to the problem of radiation reaction for multipoles. As the particular example of a general procedure we obtain the effective model for a neutral system of charged particles with dipole moment.
A Guide to Electronic Multipoles in Photon Scattering and Absorption
Lovesey, Stephen William; Balcar, Ewald
2013-02-01
The practice of replacing matrix elements in atomic calculations by those of convenient operators with strong physical appeal has a long history, and in condensed matter physics it is perhaps best known through use of operator equivalents in electron resonance by Elliott and Stevens. Likewise, electronic multipoles, created with irreducible spherical-tensors, to represent charge-like and magnetic-like quantities are widespread in modern physics. Examples in recent headlines include a magnetic charge (a monopole), an anapole (a dipole) and a triakontadipole (a magnetic-like atomic multipole of rank 5). In this communication, we aim to guide the reader through use of atomic, spherical multipoles in photon scattering, and resonant Bragg diffraction and dichroic signals in particular. Applications to copper oxide CuO and neptunium dioxide (NpO2) are described. In keeping with it being a simple guide, there is sparse use in the communication of algebra and expressions are gathered from the published literature and not derived, even when central to the exposition. An exception is a thorough grounding, contained in an Appendix, for an appropriate version of the photon scattering length based on quantum electrodynamics. A theme of the guide is application of symmetry in scattering, in particular constraints imposed on results by symmetry in crystals. To this end, a second Appendix catalogues constraints on multipoles imposed by symmetry in crystal point-groups.
Finite amplitude method applied to the giant dipole resonance in heavy rare-earth nuclei
Oishi, Tomohiro; Kortelainen, Markus; Hinohara, Nobuo
2016-03-01
Background: The quasiparticle random phase approximation (QRPA), within the framework of nuclear density functional theory (DFT), has been a standard tool to access the collective excitations of atomic nuclei. Recently, the finite amplitude method (FAM) was developed in order to perform the QRPA calculations efficiently without any truncation on the two-quasiparticle model space. Purpose: We discuss the nuclear giant dipole resonance (GDR) in heavy rare-earth isotopes, for which the conventional matrix diagonalization of the QRPA is numerically demanding. A role of the Thomas-Reiche-Kuhn (TRK) sum rule enhancement factor, connected to the isovector effective mass, is also investigated. Methods: The electric dipole photoabsorption cross section was calculated within a parallelized FAM-QRPA scheme. We employed the Skyrme energy density functional self-consistently in the DFT calculation for the ground states and FAM-QRPA calculation for the excitations. Results: The mean GDR frequency and width are mostly reproduced with the FAM-QRPA, when compared to experimental data, although some deficiency is observed with isotopes heavier than erbium. A role of the TRK enhancement factor in actual GDR strength is clearly shown: its increment leads to a shift of the GDR strength to higher-energy region, without a significant change in the transition amplitudes. Conclusions: The newly developed FAM-QRPA scheme shows remarkable efficiency, which enables one to perform systematic analysis of GDR for heavy rare-earth nuclei. The theoretical deficiency of the photoabsorption cross section could not be improved by only adjusting the TRK enhancement factor, suggesting the necessity of an approach beyond self-consistent QRPA and/or a more systematic optimization of the energy density functional (EDF) parameters.
Evolution of giant dipole resonance width at low temperatures – New perspectives
S Mukhopadhyay
2014-05-01
High energy photons from the decay of giant dipole resonances (GDR) built on excited states provide an excellent probe in the study of nuclear structure properties, damping mechanisms etc., at finite temperatures. The dependence of GDR width on temperature () and angular momentum () has been the prime focus of many experimental and theoretical studies for the last few decades. The measured GDR widths for a wide range of nuclei at temperatures (1.5 < < 2.5 MeV) and spins (upto fission limit) were well described by the thermal shape fluctuation model (TSFM). But, at low temperatures ( < 1.5 MeV) there are large discrepancies between the existing theoretical models. The problem is compounded as there are very few experimental data in this region. At Variable Energy Cyclotron Centre, Kolkata, a programme for the systematic measurement of GDR width at very low temperatures has been initiated with precise experimental techniques. Several experiments have been performed by bombarding 7–12 MeV/nucleon alpha beam on various targets (63Cu, 115In and 197Au) and new datasets have been obtained at low temperatures ( < 1.5MeV) and at very lowspins ( < 20$\\hbar$). The TSFM completely fails to represent the experimental data at these low temperatures in the entire mass range. In fact, the GDR width appears to be constant at its ground state value until a critical temperature is reached and subsequently increases thereafter, whereas the TSFM predicts a gradual increase of GDR width from its ground state value for > 0 MeV. In order to explain this discrepancy at low , a new formalism has been put forward by including GDR-induced quadrupole moment in the TSFM.
Isoscalar monopole and dipole excitations of cluster states and giant resonances in 12C
Kanada-En'yo, Yoshiko
2016-05-01
The isoscalar monopole (ISM) and dipole (ISD) excitations in 12C are investigated theoretically with the shifted antisymmetrized molecular dynamics (AMD) plus 3 α -cluster generator coordinate method (GCM). The small-amplitude vibration modes are described by coherent one-particle one-hole excitations expressed by a small shift of single-nucleon Gaussian wave functions within the AMD framework, whereas the large-amplitude cluster modes are incorporated by superposing 3 α -cluster wave functions in the GCM. The coupling of the excitations in the intrinsic frame with the rotation and parity transformation is taken into account microscopically by the angular-momentum and parity projections. The present a calculation that describes the ISM and ISD excitations over a wide energy region covering cluster modes in the low-energy region and the giant resonances in the high-energy region, although the quantitative description of the high-energy part is not satisfactory. The low-energy ISM and ISD strengths of the cluster modes are enhanced by the distance motion between α clusters, and they split into a couple of states because of the angular motion of α clusters. The low-energy ISM strengths exhaust 26% of the energy-weighted sum rule, which is consistent with the experimental data for the 12C(02+; 7.65 MeV) and 12C(03+; 10.3 MeV) measured by (e ,e') ,(α ,α') , and (6Li,6Li' ) scatterings. In the calculated low-energy ISD strengths, two 1- states (the 11- and 12- states) with the significant strengths are obtained over E =10 -15 MeV. The results indicate that the ISD excitations can be a good probe to experimentally search for new cluster states such as the 12C(12-) obtained in the present calculation.
Multipole expansion method for supernova neutrino oscillations
Duan, Huaiyu; Shalgar, Shashank, E-mail: duan@unm.edu, E-mail: shashankshalgar@unm.edu [Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM 87131 (United States)
2014-10-01
We demonstrate a multipole expansion method to calculate collective neutrino oscillations in supernovae using the neutrino bulb model. We show that it is much more efficient to solve multi-angle neutrino oscillations in multipole basis than in angle basis. The multipole expansion method also provides interesting insights into multi-angle calculations that were accomplished previously in angle basis.
Multipole vector solitons in nonlocal nonlinear media.
Kartashov, Yaroslav V; Torner, Lluis; Vysloukh, Victor A; Mihalache, Dumitru
2006-05-15
We show that multipole solitons can be made stable via vectorial coupling in bulk nonlocal nonlinear media. Such vector solitons are composed of mutually incoherent nodeless and multipole components jointly inducing a nonlinear refractive index profile. We found that stabilization of the otherwise highly unstable multipoles occurs below certain maximum energy flow. Such a threshold is determined by the nonlocality degree.
Giant Kondo Resonance of Parallel-Coupled Double Quantum Dots Embedded in an A-B Ring
CHEN Xiong-Wen; HE Da-Jiang; SONG Ke-Hui; WU Shao-Quan
2006-01-01
We theoretically study the properties of the ground state of the parallel-coupled double quantum dots embedded in a mesoscopic ring in the Kondo regime by means of the two-impurity Anderson Hamiltonian. The Hamiltonian is solved by means of the slave-boson mean-field theory. We find that in this system, the persistent current depends sensitively on both the parity of this system and the size of the ring. In the strong coupling regime, the giant sharp current peak appears, at the same time, the parity dependence of the persistent current disappears. These imply that in the strong coupling regime, there exists giant Kondo resonance and the two dots can be coupled coherently. Thus this system might be a candidate for future device applications.
HPAM: Hirshfeld partitioned atomic multipoles
Elking, Dennis M.; Perera, Lalith; Pedersen, Lee G.
2012-02-01
An implementation of the Hirshfeld (HD) and Hirshfeld-Iterated (HD-I) atomic charge density partitioning schemes is described. Atomic charges and atomic multipoles are calculated from the HD and HD-I atomic charge densities for arbitrary atomic multipole rank l on molecules of arbitrary shape and size. The HD and HD-I atomic charges/multipoles are tested by comparing molecular multipole moments and the electrostatic potential (ESP) surrounding a molecule with their reference ab initio values. In general, the HD-I atomic charges/multipoles are found to better reproduce ab initio electrostatic properties over HD atomic charges/multipoles. A systematic increase in precision for reproducing ab initio electrostatic properties is demonstrated by increasing the atomic multipole rank from l=0 (atomic charges) to l=4 (atomic hexadecapoles). Both HD and HD-I atomic multipoles up to rank l are shown to exactly reproduce ab initio molecular multipole moments of rank L for L⩽l. In addition, molecular dipole moments calculated by HD, HD-I, and ChelpG atomic charges only ( l=0) are compared with reference ab initio values. Significant errors in reproducing ab initio molecular dipole moments are found if only HD or HD-I atomic charges used. Program summaryProgram title: HPAM Catalogue identifier: AEKP_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEKP_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU General Public License v2 No. of lines in distributed program, including test data, etc.: 500 809 No. of bytes in distributed program, including test data, etc.: 13 424 494 Distribution format: tar.gz Programming language: C Computer: Any Operating system: Linux RAM: Typically, a few hundred megabytes Classification: 16.13 External routines: The program requires 'formatted checkpoint' files obtained from the Gaussian 03 or Gaussian 09 quantum chemistry program. Nature of problem: An ab initio
EXCITATION OF GIANT-RESONANCES IN PB-208, SN-120, ZR-90 AND NI-60 BY 84 MEV/NUCLEON O-17 IONS
NETO, RL; ROUSSELCHOMAZ, P; ROCHAIS, L; ALAMANOS, N; AUGER, F; GASTEBOIS, J; GILLIBERT, A; LACEY, R; MICZAIKA, A; PIERROUTSAKOU, D; BARRETTE, J; MARK, SK; TURCOTTE, R; BLUMENFELD, Y; FRASCARIA, N; GARRON, JP; ROYNETTE, JC; SCARPACI, JA; SUOMIJARVI, T; VANDERWOUDE, A; VANDENBERG, AM
1993-01-01
Elastic and inelastic scattering of 1435 MeV 170 ions on Pb-208, Sn-120, Zr-90 and Ni-60 have been measured. Hindrance in the excitation of the first 3- states is observed. Parameters of the isoscalar giant monopole and quadrupole resonances are obtained. The quadrupole resonance exhausts approximat
Brenna, Marco
2014-01-01
The self-consistent mean-field (SCMF) theory describes many properties of the ground state and excited states of the atomic nucleus, such as masses, radii, deformations and giant resonance energies. SCMF models are based on the independent particle picture where nucleons are assumed to move in a self-generated average potential. In the first part of this work, we apply a state-of-the-art SCMF approach, based on the Skyrme effective interaction, to two different excitations (viz. the pygmy dipole resonance and the isovector giant quadrupole resonance), investigating their relation with the nuclear matter symmetry energy, which corresponds to the energy cost for changing protons into neutrons and is a key parameter for the nuclear equation of state. However, SCMF models present well known limitations which require the inclusion of further dynamical correlations, e.g. the ones coming from the interweaving between single-particle and collective degrees of freedom (particle-vibration coupling - PVC). In the second...
Mi, Jian; Wang, Jianli; Pfeiffer, L. N.; West, K. W.; Baldwin, K. W.; Zhang, Chi
2016-09-01
In our high mobility p -type AlGaAs/GaAs two-dimensional hole samples, we originally observe the B -periodic oscillation induced by microwave (MW) in photovoltage (PV) measurements. In the frequency range of our measurements (5-40 GHz), the period (Δ B ) is inversely proportional to the microwave frequency (f ). The distinct oscillations come from the edge magnetoplasmon (EMP) in the high quality heavy hole system. Simultaneously, we observe the giant plasmon resonance signals in our measurements on the shallow two-dimensional hole system (2DHS).
Dolmatov, V K; Deshmukh, P C; Manson, S T
2014-01-01
The dramatic effect of the $3p \\rightarrow 3d$ giant autoionization resonance on time delay of photoemission from the $3d$ and $4s$ valence subshells of the Mn atom is unraveled. Strong sensitivity of the time delay of the $4s$ photoemission to the final-state term of the ion-remainder [${\\rm Mn^{+}}(4s^{1},$$^{5}S)$ vs. ${\\rm Mn^{+}}(4s^{1},$$^{7}S)$] is discovered. The features of time delay uncovered in Mn photoionization are expected to be general properties of transition-metal atoms and ions. The "spin-polarized" random phase approximation with exchange was employed in the study.
Wieland, O.; Bracco, A.; Camera, F.; Benzoni, G.; Blasi, N.; Brambilla, S.; Crespi, F.; Giussani, A.; Leoni, S.; Mason, P.; Million, B.; Moroni, A.; Barlini, S.; Kravchuk, V. L.; Gramegna, F.; Lanchais, A.; Mastinu, P.; Maj, A.; Brekiesz, M.; Kmiecik, M.; Bruno, M.; Geraci, E.; Vannini, G.; Casini, G.; Chiari, M.; Nannini, A.; Ordine, A.; Ormand, E.
2006-07-01
The γ decay of the giant dipole resonance (GDR) in the Ce132 compound nucleus with temperature up to ≈4MeV has been measured, using the reaction Ni64+Zn68 at Ebeam=300, 400, and 500 MeV. The γ and charged particles measured in coincidence with recoils are consistent with a fully equilibrated compound nucleus emission. The GDR width, obtained with the statistical model analysis, is found to increase almost linearly with temperature. This increase is rather well reproduced within a model including thermal shape fluctuations and the lifetime of the compound nucleus.
Measurement of the Am241(γ,n)Am240 reaction in the giant dipole resonance region
Tonchev, A. P.; Hammond, S. L.; Howell, C. R.; Huibregtse, C.; Hutcheson, A.; Kelley, J. H.; Kwan, E.; Raut, R.; Rusev, G.; Tornow, W.; Kawano, T.; Vieira, D. J.; Wilhelmy, J. B.
2010-11-01
The photodisintegration cross section of the radioactive nucleus Am241 has been obtained using activation techniques and monoenergetic γ-ray beams from the HIγS facility. The induced activity of Am240 produced via the Am241(γ,n) reaction was measured in the energy interval from 9 to 16 MeV utilizing high-resolution γ-ray spectroscopy. The experimental data for the Am241(γ,n) reaction in the giant dipole resonance energy region are compared with statistical nuclear-model calculations.
Gutberlet, Matthias; Felix, Roland [Department of Radiology and Nuclear Medicine, Charite, Campus Virchow-Klinikum, Augustenburger Platz 1, 13353 Berlin (Germany); Abdul-Khaliq, Hashim; Stiller, Brigitte; Schubert, Ulf; Lange, Peter E. [Department of Pediatric Cardiology, Deutsches Herzzentrum, Berlin (Germany); Stoltenburg-Didinger, Gisela [Department of Neuropathology, Free University Berlin, Berlin (Germany); Hetzer, Roland [Department of Cardio-, Thoracic and Vascular Surgery, Deutsches Herzzentrum Berlin (Germany)
2002-07-01
The diagnosis of a rare case of giant intraventricular fibroma in an infant by MRI in comparison with other imaging modalities, such as echocardiography and angiography, is discussed. For preoperative planning only MRI showed the myocardial infiltration. The myocardial blood supply of the tumor could be evaluated qualitatively by contrast-enhanced MRI, but the direct visualization of the distally located branches could only be assessed by coronary angiography. Magnetic resonance coronary angiography using the navigator technique failed to depict the distal part of the coronaries. The obstruction of the left ventricle outflow tract could be assessed and quantified by all imaging modalities. (orig.)
A SECOND GIANT PLANET IN 3:2 MEAN-MOTION RESONANCE IN THE HD 204313 SYSTEM
Robertson, Paul; Endl, Michael; Cochran, William D.; MacQueen, Phillip J.; Brugamyer, Erik J.; Barnes, Stuart I.; Caldwell, Caroline [Department of Astronomy and McDonald Observatory, University of Texas at Austin, Austin, TX 78712 (United States); Horner, J.; Wittenmyer, Robert A. [Department of Astrophysics and Optics, School of Physics, University of New South Wales, Sydney, NSW 2052 (Australia); Simon, Attila E., E-mail: paul@astro.as.utexas.edu [Konkoly Observatory of the Hungarian Academy of Sciences, P.O. Box 67, H-1525 Budapest (Hungary)
2012-07-20
We present eight years of high-precision radial velocity (RV) data for HD 204313 from the 2.7 m Harlan J. Smith Telescope at McDonald Observatory. The star is known to have a giant planet (Msin i = 3.5 M{sub J} ) on a {approx}1900 day orbit, and a Neptune-mass planet at 0.2 AU. Using our own data in combination with the published CORALIE RVs of Segransan et al., we discover an outer Jovian (Msin i = 1.6 M{sub J} ) planet with P {approx} 2800 days. Our orbital fit suggests that the planets are in a 3:2 mean motion resonance, which would potentially affect their stability. We perform a detailed stability analysis and verify that the planets must be in resonance.
Simoes, Fernando; Pfaff, Robert; Hamelin, Michel; Klenzing, Jeffrey; Freudenreich, Henry; Beghin, Christian; Berthelier, Jean-Jacques; Bromund, Kenneth; Grard, Rejean; Lebreton, Jean-Pierre; Martin, Steven; Rowland, Douglas; Sentman, Davis; Takahashi, Yukihiro; Yair, Yoav
2012-01-01
The formation and evolution of the Solar System is closely related to the abundance of volatiles, namely water, ammonia, and methane in the protoplanetary disk. Accurate measurement of volatiles in the Solar System is therefore important to understand not only the nebular hypothesis and origin of life but also planetary cosmogony as a whole. In this work, we propose a new, remote sensing technique to infer the outer planets water content by measuring Tremendously and Extremely Low Frequency (TLF-ELF) electromagnetic wave characteristics (Schumann resonances) excited by lightning in their gaseous envelopes. Schumann resonance detection can be potentially used for constraining the uncertainty of volatiles of the giant planets, mainly Uranus and Neptune, because such TLF-ELF wave signatures are closely related to the electric conductivity profile and water content.
Podlewska-Gaca, Edyta
2013-01-01
In this paper we investigate the possibility of a migration-induced resonance locking in systems containing three planets, namely an Earth analog, a super-Earth and a gas giant. The planets have been listed in order of increasing orbital periods. All three bodies are embedded in a locally isothermal gaseous disc and orbit around a solar mass star. We are interested in answering the following question: Will the low-mass planets form the same resonant structures with each other in the vicinity of the gas giant as in the case when the gas giant is absent? When there is no gas giant in the system, it has been already shown that if the two low-mass planets undergo a convergent differential migration, they will capture each other in a mean-motion resonance. For the choices of disc parameters and planet masses made in this paper, the formation of the 5:4 resonance in the absence of the Jupiter has been observed. In this work we add a gas giant on the most external orbit of the system in such a way that its different...
Ciemała, M.; Kmiecik, M.; Maj, A.; Mazurek, K.; Bracco, A.; Kravchuk, V. L.; Casini, G.; Barlini, S.; Baiocco, G.; Bardelli, L.; Bednarczyk, P.; Benzoni, G.; Bini, M.; Blasi, N.; Brambilla, S.; Bruno, M.; Camera, F.; Carboni, S.; Cinausero, M.; Chbihi, A.; Chiari, M.; Corsi, A.; Crespi, F. C. L.; D'Agostino, M.; Degerlier, M.; Fornal, B.; Giaz, A.; Gramegna, F.; Krzysiek, M.; Leoni, S.; Marchi, T.; Matejska-Minda, M.; Mazumdar, I.; Meczyński, W.; Million, B.; Montanari, D.; Morelli, L.; Myalski, S.; Nannini, A.; Nicolini, R.; Pasquali, G.; Piantelli, S.; Prete, G.; Roberts, O. J.; Schmitt, Ch.; Styczeń, J.; Szpak, B.; Valdré, S.; Wasilewska, B.; Wieland, O.; Wieleczko, J. P.; Ziebliński, M.; Dudek, J.; Dinh Dang, N.
2015-05-01
High-energy giant dipole resonance (GDR) γ rays were measured following the decay of the hot, rotating compound nucleus of 88Mo, produced at excitation energies of 124 and 261 MeV. The reaction 48Ti + 40Ca at 300 and 600 MeV bombarding energies has been used. The data were analyzed using the statistical model Monte Carlo code gemini++. It allowed extracting the giant dipole resonance parameters by fitting the high-energy γ -ray spectra. The extracted GDR widths were compared with the available data at lower excitation energy and with theoretical predictions based on (i) The Lublin-Strasbourg drop macroscopic model, supplemented with thermal shape fluctuations analysis, and (ii) The phonon damping model. The theoretical predictions were convoluted with the population matrices of evaporated nuclei from the statistical model gemini++. Also a comparison with the results of a phenomenological expression based on the existing systematics, mainly for lower temperature data, is presented and discussed. A possible onset of a saturation of the GDR width was observed around T =3 MeV.
Vacuum energies and multipole interactions
Rangel, Fabricio Augusto Barone
2016-01-01
In this paper, we present a quantum-field-theoretical description of the interaction between stationary and localized external sources linearly coupled to bosonic fields (specifically, we study models with a scalar and the Maxwell field). We consider external sources that simulate not only point charges but also higher-multipole distributions along D-dimensional branes. Our results complement the ones previously obtained in reference [1].
Kaon photoproduction in a multipole approach
Mart, T
2006-01-01
The recently published experimental data on K+Lambda photoproduction by the SAPHIR, CLAS, and LEPS collaborations are analyzed by means of a multipole approach. For this purpose the background amplitudes are constructed from appropriate Feynman diagrams in a gauge-invariant and crossing-symmetric fashion. The results of our calculation emphasize the lack of mutual consistency between the SAPHIR and CLAS data previously found by several independent research groups, whereas the LEPS data are found to be more consistent with those of CLAS. The use of SAPHIR and CLAS data, individually or simultaneously, leads to quite different resonance parameters which, therefore, could lead to different conclusions on ``missing resonances''. Fitting to the SAPHIR and LEPS data simultaneously indicates that the S_{11}(1650), P_{13}(1720), D_{13}(1700), D_{13}(2080), F_{15}(1680), and F_{15}(2000) resonances are required, while fitting to the combination of CLAS and LEPS data leads alternatively to the P_{13}(1900), D_{13}(2080...
Yoo, Sung Hoon.
1990-05-01
Angular distributions for the {sup 12}C({pi}{sup {plus minus}}, {pi}{sup {plus minus}}{prime} p) and {sup 208}Pb({pi}{sup {plus minus}}, {pi}{sup {plus minus}}{prime} p or n) reactions near the giant resonance region have been measured at T{sub {pi}} = 180 MeV, and found different between {pi}{sup +} and {pi}{sup {minus}} data. This observation is interpreted as evidence for different excitation mechanisms dominating the {pi}{sup {minus}}-nucleus and {pi}{sup +}-nucleus interactions in the giant resonance region of these targets. A comparison with the single-nucleon knock-out distorted-wave impulse approximation calculations shows, even though these calculations underestimate ({pi}{sup {plus minus}}, {pi}{sup {plus minus}}{prime} N) data for both targets, the dominance of direct process for ({pi}{sup +}, {pi}{sup {plus}}{prime} p) or ({pi}{sup {minus}}, {pi}{sup {minus}}{prime} n) in contrast to ({pi}{sup {minus}}, {pi}{sup {minus}}{prime} p) or ({pi}{sup +}, {pi}{sup +}{prime} n). In the ({pi}{sup +}, {pi}{sup +}{prime} p) reaction proton-proton hole states are excited directly and appear to have a large probability for direct decay with escape width, whereas in ({pi}{sup {minus}}, {pi}{sup {minus}}{prime} p) the preferentially excited neutron-neutron hole doorway states couple to resonance states and decay with spreading width. This interpretation led us to suggest that the ratio of cross-sections for inelastic scattering to the giant resonance region should be written in terms of an incoherent sum of cross-sections to neutron and proton doorway states. In a heavy nucleus such as {sup 208}Pb, neutron and proton doorway states. In a heavy nucleus such as {sup 208}Pb, neutron and proton doorway states contribute incoherently because the different decay processes do not populate the same final states of the residual nucleus.
Electromagnetic multipole fields of neutron stars
Roberts, W. J.
1979-01-01
A formalism is developed for treating general multipole electromagnetic fields of neutron stars. The electric multipoles induced in a neutron star by its rotation with an arbitrary magnetic multipole at its center are presented. It is shown how to express a family of off-centered multipoles having the same l weight as an infinite array of centered multipoles of increasing l weight referred to the rotational axis. General expressions are given for the linear momentum present in the superposition of arbitrary multipole fields, and the results are combined to compute the radiation rate of linear momentum by an off-centered dipole to zeroth order in the parameter Omega x R/c. The general Deutsch (1955) solution is then rederived in a clear consistent manner, and some minor additions and corrections are provided.
Multipole surface solitons in layered thermal media
Kartashov, Yaroslav V; Torner, Lluis
2008-01-01
We address the existence and properties of multipole solitons localized at a thermally insulating interface between uniform or layered thermal media and a linear dielectric. We find that in the case of uniform media, only surface multipoles with less than three poles can be stable. In contrast, we reveal that periodic alternation of the thermo-optic coefficient in layered thermal media makes possible the stabilization of higher order multipoles.
Beu, Steven C; Hendrickson, Christopher L; Marshall, Alan G
2011-03-01
Radiofrequency (rf) multipole ion guides are widely used to transfer ions through the strong magnetic field gradient between source and analyzer regions of external source Fourier transform ion cyclotron resonance mass spectrometers. Although ion transfer as determined solely by the electric field in a multipole ion guide has been thoroughly studied, transfer influenced by immersion in a strong magnetic field gradient has not been as well characterized. Recent work has indicated that the added magnetic field can have profound effects on ion transfer, ultimately resulting in loss of ions initially contained within the multipole. Those losses result from radial ejection of ions due to transient cyclotron resonance that occurs when ions traverse a region in which the magnetic field results in an effective cyclotron frequency equal to the multipole rf drive frequency divided by the multipole order (multipole order is equal to one-half the number of poles). In this work, we describe the analytical basis for ion resonance in a rf multipole ion guide with superposed static magnetic field and compare with results of numerical trajectory simulations. © American Society for Mass Spectrometry, 2011
Podlewska-Gaca, E.; Szuszkiewicz, E.
2014-03-01
In this paper we investigate the possibility of a migration-induced resonance locking in systems containing three planets, namely an Earth analogue (1 M⊕), a super-Earth (4 M⊕) and a gas giant (one Jupiter mass). The planets have been listed in order of increasing orbital periods. All three bodies are embedded in a locally isothermal gaseous disc and orbit around a solar mass star. We are interested in answering the following questions: will the low-mass planets form the same resonant structures with each other in the vicinity of the gas giant as in the case when the gas giant is absent? More in general, how will the presence of the gas giant affect the evolution of the two low-mass planets? When there is no gas giant in the system, it has been already shown that if the two low-mass planets undergo a convergent differential migration, they will capture each other in a mean-motion resonance. For the choices of disc parameters and planet masses made in this paper, the formation of the 5:4 resonance in the absence of the Jupiter has been observed in a previous investigation and confirmed here. In this work we add a gas giant on the most external orbit of the system in such a way that its differential migration is convergent with the low-mass planets. We show that the result of this set-up is the speeding up of the migration of the super-Earth and, after that, all three planets become locked in a triple mean-motion resonance. However, this resonance is not maintained due to the low-mass planet eccentricity excitation, a fact that leads to close encounters between planets and eventually to the ejection from the internal orbits of one or both low-mass planets. We have observed that the ejected low-mass planets can leave the system, fall into a star or become the external planet relative to the gas giant. In our simulations the latter situation has been observed for the super-Earth. It follows from the results presented here that the presence of a Jupiter-like planet
Leo, R. de; Harakeh, M.N.; Micheletti, S.; Plicht, J. van der; van der Woude, Adriaan; David, P.; Janszen, H.
1982-01-01
A measurement of the α-spectrum in the region of the isoscalar giant resonances from 238U at Eα = 120 MeV in coincidence with out-of-plane fission fragments shows the validity of the hypothesis of axial symmetry with respect to the recoil axis. Similar to what was observed in previous in-plane
Dinh Dang, N.; Ciemala, M.; Kmiecik, M.; Maj, A.
2013-05-01
The line shapes of giant dipole resonance (GDR) in the decay of the compound nucleus 88Mo, which is formed after the fusion-evaporation reaction 48Ti + 40Ca at various excitation energies E* from 58 to 308 MeV, are generated by averaging the GDR strength functions predicted within the phonon damping model (PDM) using the empirical probabilities for temperature and angular momentum. The average strength functions are compared with the PDM strength functions calculated at the mean temperature and mean angular momentum, which are obtained by averaging the values of temperature and angular momentum using the same temperature and angular momentum probability distributions, respectively. It is seen that these two ways of generating the GDR linear line shape yield very similar results. It is also shown that the GDR width approaches a saturation at angular momentum J≥ 50 ℏ at T=4 MeV and at J≥ 70 ℏ at any T.
Dang, N Dinh; Kmiecik, M; Maj, A
2013-01-01
The line shapes of giant dipole resonance (GDR) in the decay of the compound nucleus $^{88}$Mo, which is formed after the fusion-evaporation reaction $^{48}$Ti + $^{40}$Ca at various excitation energies $E^{*}$ from 58 to 308 MeV, are generated by averaging the GDR strength functions predicted within the phonon damping model (PDM) using the empirical probabilities for temperature and angular momentum. The average strength functions are compared with the PDM strength functions calculated at the mean temperature and mean angular momentum, which are obtained by averaging the values of temperature and angular momentum using the same temperature and angular-momentum probability distributions, respectively. It is seen that these two ways of generating the GDR linear line shape yield very similar results. It is also shown that the GDR width approaches a saturation at angular momentum $J\\geq$ 50$\\hbar$ at $T=$ 4 MeV and at $J\\geq$ 70$\\hbar$ at any $T$.
Sil, T; Reinhard, P G; Shlomo, S; Sil, Tapas
2006-01-01
We provide accurate assessments of the consequences of violations of self-consistency in Hartree-Fock (HF) based random phase approximation (RPA) calculations of the centroid energy $E_{cen}$ of isoscalar and isovector giant resonances of multi-polarities $L=0-3$ in a wide range of nuclei. This is done by carrying out highly accurate HF-RPA calculations neglecting the particle-hole (ph) spin-orbit or Coulomb interaction in the RPA and comparing with the fully self-consistent HF-RPA results. We find that the shifts in the value of $E_{cen}$ due to self-consistency violation associated with the spin-orbit and Coulomb interactions are comparable or larger than the current experimental errors in $E_{cen}$.
Multipole Moments of numerical spacetimes
Pappas, George
2012-01-01
In this article we present some recent results on identifying correctly the relativistic multipole moments of numerically constructed spacetimes, and the consequences that this correction has on searching for appropriate analytic spacetimes that can approximate well the previously mentioned numerical spacetimes. We also present expressions that give the quadrupole and the spin octupole as functions of the spin parameter of a neutron star for various equations of state and in a range of masses for every equation of state used. These results are relevant for describing the exterior spacetime of rotating neutron stars that are made up of matter obeying realistic equations of state.
Description of complex time series by multipoles
Lewkowicz, M.; Levitan, J.; Puzanov, N.
2002-01-01
We present a new method to describe time series with a highly complex time evolution. The time series is projected onto a two-dimensional phase-space plot which is quantified in terms of a multipole expansion where every data point is assigned a unit mass. The multipoles provide an efficient...... characterization of the original time series....
Hendrie, James; Diels, Jean Claude; Arissian, Ladan
2016-01-01
Intracavity Phase Interferometry is a phase sensing technique using mode-locked lasers in which two intracavity pulses circulate. The beat frequency between the two output frequency combs is proportional to a phase shift to be measured. A laser gyro is a particular implementation of this device. The demonstrated sensitivity of $10^{-8}$ could be manipulated by applying a giant dispersion to each tooth of the comb. Such coupling is achieved with an intracavity etalon, resulting a large change in phase response of a ring laser. This change is shown to be unrelated to the average pulse velocity within the laser cavity.
Kirby, Kate; Babb, J.; Yoshino, K.
2004-01-01
In L-dwarfs and T-dwarfs the resonance lines of sodium and potassium are so profoundly pressure-broadened that their wings extend several hundred nanometers from line center. With accurate knowledge of the line profiles as a function of temperature and pressure: such lines can prove to be valuable diagnostics of the atmospheres of such objects. We have initiated a joint program of theoretical and experimental research to study the line-broadening of alkali atom resonance lines due to collisions with species such as helium and molecular hydrogen. Although potassium and sodium are the alkali species of most interest in the atmospheres of cool brown dwarfs and extrasolar giant planets, some of our theoretical focus this year has involved the calculation of pressure-broadening of lithium resonance lines by He, as a test of a newly developed suite of computer codes. In addition, theoretical calculations have been carried out to determine the leading long range van der Waals coefficients for the interactions of ground and excited alkali metal atoms with helium atoms, to within a probable error of 2%. Such data is important in determining the behavior of the resonance line profiles in the far wings. Important progress has been made on the experimental aspects of the program since the arrival of a postdoctoral fellow in September. A new absorption cell has been designed, which incorporates a number of technical improvements over the previous cell, including a larger cell diameter to enhance the signal, and fittings which allow for easier cleaning, thereby significantly reducing the instrument down-time.
Hasan, Hashima (Technical Monitor); Kirby, K.; Babb, J.; Yoshino, K.
2005-01-01
We report on progress made in a joint program of theoretical and experimental research to study the line-broadening of alkali atom resonance lines due to collisions with species such as helium and molecular hydrogen. Accurate knowledge of the line profiles of Na and K as a function of temperature and pressure will allow such lines to serve as valuable diagnostics of the atmospheres of brown dwarfs and extra-solar giant planets. A new experimental apparatus has been designed, built and tested over the past year, and we are poised to begin collecting data on the first system of interest, the potassium resonance lines perturbed by collisions with helium. On the theoretical front, calculations of line-broadening due to sodium collisions with helium are nearly complete, using accurate molecular potential energy curves and transition moments just recently computed for this system. In addition we have completed calculations of the three relevant potential energy curves and associated transition moments for K - He, using the MOLPRO quantum chemistry codes. Currently, calculations of the potential surfaces describing K-H2 are in progress.
Multipole shimming of permanent magnets using harmonic corrector rings.
Jachmann, R C; Trease, D R; Bouchard, L-S; Sakellariou, D; Martin, R W; Schlueter, R D; Budinger, T F; Pines, A
2007-03-01
Shimming systems are required to provide sufficient field homogeneity for high resolution nuclear magnetic resonance (NMR). In certain specialized applications, such as rotating-field NMR and mobile ex situ NMR, permanent magnet-based shimming systems can provide considerable advantages. We present a simple two-dimensional shimming method based on harmonic corrector rings which can provide arbitrary multipole order shimming corrections. Results demonstrate, for example, that quadrupolar order shimming improves the linewidth by up to an order of magnitude. An additional order of magnitude reduction is in principle achievable by utilizing this shimming method for z-gradient correction and higher order xy gradients.
Multipole approach for photo- and electroproduction of kaon
Mart, T
2007-01-01
We have analyzed the experimental data on K+Lambda photoproduction by using a multipole approach. In this analysis we use the background amplitudes constructed from appropriate Feynman diagrams in a gauge-invariant and crossing-symmetric fashion. Results of our analysis reveal the problem of mutual consistency between the new SAPHIR and CLAS data. We found that the problem could lead to different conclusions on ``missing resonances''. We have also extended our analysis to the finite Q^2 region and compared the result with the corresponding electroproduction data.
On the Fly Doppler Broadening Using Multipole Representation
Khassenov, Azamat; Choi, Sooyoung; Lee, Deokjung [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)
2015-05-15
On the Fly Doppler broadening is the technique to avoid pre-generation of the microscopic cross section, in other words, reduce the amount of storage. Currently, there are different types of formalisms used by NJOY code to generate reaction cross section and accomplish its Doppler broadening. Single-Level Breit-Wigner (SLBW) formalism is limited to well-separated resonances, in other words, it does not consider interference between energy levels. Multi-Level Breit- Wigner formalism (MLBW) was tested as the candidate for the cross section generation in the Monte Carlo code, which is under development in UNIST. According to the results, MLBW method requires huge amount of computational time to produce cross section at certain energy point. Reich-Moore (RM) technique can generate only 0K cross section, which means that it cannot produce broaden cross section directly from resonance parameters. The first step was to convert resonance parameters given in nuclear data file into multipoles. MPR shows very high potential to be used as the formalism in the on-the-fly Doppler broadening module of MCS. One of the main reasons is that comparison of the time cost shown in Table IV supports application of multipole representation.
THE ANGULAR-MOMENTUM DEPENDENCE OF THE GIANT-DIPOLE RESONANCE IN DY-154
NOORMAN, RF; BACELAR, JC; HARAKEH, MN; HESSELINK, WHA; HOFMANN, HJ; Kalantar-Nayestanaki, Nasser; VANSCHAGEN, JPS; STOLK, A; SUJKOWSKI, Z; DEVOIGT, MJA; VANDERWOUDE, A
1994-01-01
The statistical gamma-ray decay of the compound nucleus 154Dy* formed at an excitation energy of 69 MeV is studied in three angular-momentum windows [J] = 31,42 and 50h. The GDR strength function extracted from the data indicates a constant centroid energy for the resonance E(GDR) = 15.2 +/- 0.5 MeV
Giant Goos-Hänchen effect and Fano resonance at photonic crystal surfaces.
Soboleva, I V; Moskalenko, V V; Fedyanin, A A
2012-03-23
The Goos-Hänchen effect and Fano resonance are studied in photonic crystals that are considered Fourier counterparts in wave-vector-coordinate space. The Goos-Hänchen effect, which is enhanced by the excitation of Bloch surface electromagnetic waves, is visualized using far-field microscopy and measured at the surface of photonic crystals by angular spectroscopy. The maximal Goos-Hänchen shift is observed to be 66 μm.
Apparatus and method of dissociating ions in a multipole ion guide
Webb, Ian K.; Tang, Keqi; Smith, Richard D.; Ibrahim, Yehia M.; Anderson, Gordon A.
2014-07-08
A method of dissociating ions in a multipole ion guide is disclosed. A stream of charged ions is supplied to the ion guide. A main RF field is applied to the ion guide to confine the ions through the ion guide. An excitation RF field is applied to one pair of rods of the ion guide. The ions undergo dissociation when the applied excitation RF field is resonant with a secular frequency of the ions. The multipole ion guide is, but not limited to, a quadrupole, a hexapole, and an octopole.
Cao, L G; Colo', G; Sagawa, H
2015-01-01
We investigate the impact of the neutron-skin thickness Delta(R) on the energy difference between the anti-analog giant dipole resonance (AGDR), E(AGDR), and the isobaric analog state (IAS), E(IAS), in a heavy nucleus such as 208Pb. For guidance, we first develop a simple and analytic, yet physical, approach based on the Droplet Model that linearly connects the energy difference E(AGDR)-E(IAS) with Delta(R). To test this correlation on more fundamental grounds, we employ a family of systematically varied Skyrme energy density functionals where variations on the value of the symmetry energy at saturation density J are explored. The calculations have been performed within the fully self consistent Hartree-Fock (HF) plus charge-exchange random phase approximation (RPA) framework. We confirm the linear correlation within our microscopic apporach and, by comparing our results with available experimental data in 208Pb, we find that our analysis is consistent with Delta(R) = 0.204 \\pm 0.009 fm, J = 31.4 \\pm 0.5 MeV ...
Tribelsky, M I
2015-01-01
A detailed analytical inspection of light scattering by a particle with high refractive index m+i\\kappa and small dissipative constant \\kappa is presented. We have shown that there is a dramatic difference in the behavior of the electromagnetic field within the particle (inner problem) and the scattered field outside it (outer problem). With an increase in m at fix values of the other parameters, the field within the particle asymptotically converges to a periodic function of m. The electric and magnetic type Mie resonances of different orders overlap substantially. It may lead to a giant concentration of the electromagnetic energy within the particle. At the same time, we demonstrate that identical transformations of the solution for the outer problem allow to present each partial scattered wave as a sum of two partitions. One of them corresponds to the m-independent wave, scattered by a perfectly reflecting particle and plays the role of a background, while the other is associated with the excitation of a s...
Dang, Nguyen Dinh
2007-04-01
Thermal fluctuations of quasiparticle number are included making use of the secondary Bogolyubov's transformation, which turns quasiparticles operators into modified-quasiparticle ones. This restores the unitarity relation for the generalized single-particle density operator, which is violated within the Hartree-Fock-Bogolyubov (HFB) theory at finite temperature. The resulting theory is called the modified HFB (MHFB) theory, whose limit of a constant pairing interaction yields the modified BCS (MBCS) theory. Within the MBCS theory, the pairing gap never collapses at finite temperature T as it does within the BCS theory, but decreases monotonously with increasing T. It is demonstrated that this non-vanishing thermal pairing is the reason why the width of the giant dipole resonance (GDR) does not increase with T up to T ~ 1 MeV. At higher T, when the thermal pairing is small, the GDR width starts to increase with T. The calculations within the phonon-damping model yield the results in good agreement with the most recent experimental systematic for the GDR width as a function of T. A similar effect, which causes a small GDR width at low T, is also seen after thermal pairing is included in the thermal fluctuation model.
Giant peak to valley ratio in a GaN based resonant tunnel diode with barrier width modulation
Sankaranarayanan, Sandeep; Saha, Dipankar
2016-10-01
A barrier width modulated GaN based resonant tunnel diode is theoretically proposed which exhibits a giant peak to valley current ratio as high as 60 and a high negative differential conductance (NDC) of 1.77 × 106 S/cm2 with very low valley current density of 3 mA/cm2. This is achieved by the unique characteristic of the device current which monotonically decreases for applied voltages greater than the valley voltage in our simulation window. This is in contrast to all the other negative differential conductance based devices which experience an immediate exponential increase in current after the NDC region. The proposed device is also the first bidirectional tunneling diode which shows negative differential conductance for both polarity of the applied bias which is normally not observed with the conventional GaN/AlGaN double barrier structures due to the strong asymmetry arising from the internal electric fields due to polarization. The unique characteristics of the device can be attributed to the use of a modulated barrier width which is made possible by a polarization modulating InGaN layer and efficient utilization of internal electric fields in III-nitrides.
Wieland, O; Bracco, A; Camera, F; Benzoni, G; Blasi, N; Brambilla, S; Crespi, F; Giussani, A; Leoni, S; Million, B; Moroni, A; Barlini, S; Kravchuk, V L; Gramegna, F; Lanchais, A; Mastinu, P; Maj, A; Brekiesz, M; Kmiecik, M; Bruno, M; Geraci, E; Vannini, G; Casini, G; Chiari, M; Nannini, A; Ordine, A; Ormand, W E
2006-06-16
The {gamma} decay of the Giant Dipole Resonance in the {sup 132}Ce compound nucleus with temperature up to {approx} 4 MeV has been measured. The symmetric {sup 64}Ni + {sup 68}Zn at E{sub beam} = 300, 400, 500 MeV and the asymmetric reaction {sup 16}O + {sup 116}Sn at E{sub beam} = 130, 250 MeV have been investigated. Light charged particles and {gamma} rays have been detected in coincidence with the recoiling compound system. In the case of the mass symmetric {sup 64}Ni induced reaction the {gamma} and charged particle spectral shapes are found to be consistent with the emission from a fully equilibrated compound nuclei and the GDR parameters are extracted from the data using a statistical model analysis. The GDR width is found to increase almost linear with temperature. This increase is rather well reproduced within a model which includes both the thermal fluctuation of the nuclear shape and the lifetime of the compound nucleus.
Thiep, Tran Duc; An, Truong Thi; Cuong, Phan Viet; Vinh, Nguyen The; Hue, Bui Minh; Belov, A. G.; Maslov, O. D.; Mishinsky, G. V.; Zhemenik, V. I.
2017-01-01
We have determined the isomeric ratios of isomeric pairs 97m,gNb, 95m,gNb and 91m,gMo produced in 98Mo(γ, p)97m,gNb, 96Mo(γ, p)95m,gNb and 92Mo(γ, n)91m,gMo photonuclear reactions in the giant dipole resonance (GDR) region by the activation method. The results were analyzed, discussed and compared with the similar data from literature to examine the role of excitation energy, neutron configuration, channel effect and direct and pre-equilibrium processes in (γ, p) photonuclear reactions. In this work the isomeric ratios for 97m,gNb from 14 to 19 MeV, for 195m,gNb from14 to 24 MeV except 20 and 23.5 MeV and for 91m,gMo at 14 and 15 MeV are the first time measurements.
Electric dipole strength distribution below the E1 giant resonance in N = 82 nuclei
Guliyev, Ekber; Kuliev, Ali; Guner, Mehmet
2010-12-01
In this study quasiparticle random-phase approximation with the translational invariant Hamiltonian using deformed mean field potential has been conducted to describe electric dipole excitations in 136Xe, 138Ba, 140Ce, 142Nd, 144Sm and 146Gd isotones. The distribution of the calculated E1 strength shows a resonance like structure at energies between 6-8 MeV exhausting up to 1% of the isovector electric dipole Energy Weighted Sum Rule and in some aspects nicely confirms the experimental data. It has been shown that the main part of E1 strength, observed below the threshold in these nuclei may be interpreted as main fragments of the Pygmy Dipole resonance. The agreement between calculated mean excitation energies as well as summed B(E1) value of the 1- excitations and the available experimental data is quite good. The calculations indicate the presence of a few prominent positive parity 1+ States in heavy N = 82 isotones in the energy interval 6-8 MeV which shows not all dipole excitations were of electric character in this energy range.
Huang, Pu; Zhou, Jingwei; Zhang, Liang; Hou, Dong; Lin, Shaochun; Deng, Wen; Meng, Chao; Duan, Changkui; Ju, Chenyong; Zheng, Xiao; Xue, Fei; Du, Jiangfeng
2016-05-01
Nonlinearity in macroscopic mechanical systems may lead to abundant phenomena for fundamental studies and potential applications. However, it is difficult to generate nonlinearity due to the fact that macroscopic mechanical systems follow Hooke's law and respond linearly to external force, unless strong drive is used. Here we propose and experimentally realize high cubic nonlinear response in a macroscopic mechanical system by exploring the anharmonicity in chemical bonding interactions. We demonstrate the high tunability of nonlinear response by precisely controlling the chemical bonding interaction, and realize, at the single-bond limit, a cubic elastic constant of 1 × 1020 N m-3. This enables us to observe the resonator's vibrational bi-states transitions driven by the weak Brownian thermal noise at 6 K. This method can be flexibly applied to a variety of mechanical systems to improve nonlinear responses, and can be used, with further improvements, to explore macroscopic quantum mechanics.
High-Resolution Measurement of the {sup 4}He({gamma},n) Reaction in the Giant Resonance Region
Nilsson, Bjoern
2003-03-01
A comprehensive near-threshold {sup 4}He(gamma,n) absolute cross section measurement has been performed at the high-resolution tagged-photon facility MAX-lab located in Lund, Sweden. The 20 < Eg < 45 MeV tagged photons (covering the Giant Dipole Resonance energy region) were directed towards a liquid {sup 4}He target, and knocked-out neutrons were detected in a pair of 60 cm x 60 cm vetoed NE213A liquid scintillator arrays. The intense and varying charge-neutral experimental backgrounds were carefully quantified and removed from the data using a precision fitting procedure. Eight average laboratory angles (30, 45, 60, 75, 90, 105, 120, and 135 deg) were investigated for eight photon energy bins (25, 27, 29, 31, 35, 36, 39, and 41 MeV), resulting in 64 differential cross sections. These angular distributions were integrated to produce total cross sections as a function of photon energy. The resulting cross sections peak at 1.9 mb at a photon energy of 27 MeV, and fall off to a near-constant value of 1.1 mb by 36 MeV. Further, they are in excellent agreement with those measured by Sims et al. using tagged photons in the Quasi-Deuteron energy region. Overall, the results favor modern theoretical models which are based upon a charge-symmetric nucleon-nucleon force, in marked contrast to the recommendations made by Calarco et al. in 1983 based on the sparse {sup 4}He(gamma,n) data available at the time.
Wittenmyer, Robert A; Butler, R P; Horner, Jonathan; Wang, Liang; Robertson, Paul; Jones, M I; Jenkins, J S; Brahm, R; Tinney, C G; Mengel, M W; Clark, J
2015-01-01
We report the discovery of two giant planets orbiting the K giant HD 33844 based on radial velocity data from three independent campaigns. The planets move on nearly circular orbits with semimajor axes $a_b=1.60\\pm$0.02 AU and $a_c=2.24\\pm$0.05 AU, and have minimum masses (m sin $i$) of $M_b=1.96\\pm$0.12 Mjup and $M_c=1.76\\pm$0.18 Mjup. Detailed N-body dynamical simulations show that the two planets remain on stable orbits for more than $10^6$ years for low eccentricities, and are most likely trapped in a mutual 3:5 mean-motion resonance.
Maher, M.M. [Department of Radiology, Mater Misericordiae Hospital, Dublin (Ireland); Department of Radiology, St. Vincent' s Hospital, Elm Park, Dublin 4 (Ireland); Kennedy, J.; Hynes, D. [Department of Orthopaedics, Mater Misericordiae Hospital, Dublin (Ireland); Murray, J.G.; O' Connell, D. [Department of Radiology, Mater Misericordiae Hospital, Dublin (Ireland)
2000-03-30
We describe the imaging features of a giant geode of the distal humerus in a patient with rheumatoid arthritis, which presented initially as a pathological fracture. The value of magnetic resonance imaging in establishing this diagnosis is emphasized. (orig.)
A pragmatic overview of fast multipole methods
Strickland, J.H.; Baty, R.S.
1995-12-01
A number of physics problems can be modeled by a set of N elements which have pair-wise interactions with one another. A direct solution technique requires computational effort which is O(N{sup 2}). Fast multipole methods (FMM) have been widely used in recent years to obtain solutions to these problems requiring a computational effort of only 0 (N lnN) or O (N). In this paper we present an overview of several variations of the fast multipole method along with examples of its use in solving a variety of physical problems.
Simulation of Monopole and Multipole Seismoelectric Logging
Zhiwen Cui
2011-01-01
Full Text Available In a fluid-saturated porous formation, acoustics and electromagnetic waves are coupled based on Pride seismoelectric theory. An exact treatment of the nonaxisymmetric seismoelectric field excited by acoustic multipole sources is presented. The frequency wavenumber domain representations of the acoustic field and associated seismoelectric field due to acoustic multipole sources are formulated. The full waveforms of acoustic waves and electric and magnetic fields in the time domain propagation in borehole are simulated by using discrete wave number integration, and frequency versus axial-wave number responses are presented and analyzed.
Patel, D; Fujiwara, M; Adachi, T; Akimune, H; Berg, G P A; Harakeh, M N; Itoh, M; Iwamoto, C; Long, A; Matta, J T; Murakami, T; Okamoto, A; Sault, K; Talwar, R; Uchida, M; Yosoi, M
2013-01-01
Using inelastic $\\alpha$-scattering at extremely forward angles, including $0^\\circ$, the strength distributions of the isoscalar giant monopole resonance (ISGMR) have been measured in the $^{204,206,208}$Pb isotopes in order to examine the proposed mutually enhanced magicity (MEM) effect on the nuclear incompressibility. The MEM effect had been suggested as a likely explanation of the "softness" of nuclear incompressibility observed in the ISGMR measurements in the Sn and Cd isotopes. Our experimental results rule out any manifestation of the MEM effect in nuclear incompressibility and leave the question of the softness of the open-shell nuclei unresolved still.
Winchenbach, J.; Pingel, K.; Holzwarth, G.; Kühner, G.; Richter, A.
1983-11-01
The fine structure observed in high resolution inelastic electron scattering data obtained at DALINAC for 208Pb in the excitation energy range of the giant quadrupole resonance (GQR) has been analysed under the assumption that the measured strongly fragmented E2 strength distribution is due to the coupling of one or two doorway states to a large number of more complicated states. The coupling matrix elements derived from the analysis allow the determination of the escape and spreading widths Γ ↑ and Γ ↓, the excitation energies Ed, the energy shifts ΔEd, and their energy dependence, for the underlying doorways.
Bodrov, I.V.; Davydov, M.G.; Rakhmanov, I.B. [Rostov State Univ., Rostov-na-Donu (Russian Federation)] [and others
1994-08-01
The isomeric yield ratios Y{sub m}/Y{sub g} of the {sup 90}Zr({gamma},n){sup 88m,g}Zr reaction are measured in the energy range from 13 to 21 MeV with a step of 0.5 MeV. The experimental isomeric ratios are compared with the data obtained by other authors and with the results of theoretical calculations based on the statistical theory and on the model of {open_quotes}semidirect{close_quotes} decay of the giant dipole resonance. 30 refs., 1 fig., 2 tabs.
Suppressing CMB low multipoles with ISW effect
Das, Santanu
2013-01-01
Recent results of Planck data reveal that the power in the low multipoles of the CMB angular power spectrum, approximately up to $l=30$, is significantly lower than the theoretically predicted in the best fit $\\Lambda$CDM model. In this paper we investigate the possibility of invoking the Integrated Sachs-Wolfe (ISW) effect to explain this power deficit at low multipoles. The ISW effect that originates from the late time expansion history of the universe is rich in possibilities given the limited understanding of the origin of dark energy (DE). It is a common understanding that the ISW effect adds to the power at the low multipoles of the CMB angular power spectrum. In this paper we carry out an analytic study to show that there are some expansion histories in which the ISW effect, instead of adding power, provides negative contribution to the power at low multipoles. Guided by the analytic study, we present examples of the features required in the late time expansion history of the universe that could explai...
Joon-Il Choi
2013-01-01
Full Text Available Choledochal cysts are uncommon congenital anomalies of the biliary tree, commonly presenting in infancy, generally in the 1 st year of life. Presentation in adult life is less common, accounting for 20% of cases. A 19-year-old female patient presented to the Emergency Department with severe abdominal distension, a palpable abdominal mass, mild jaundice and low grade fever. Ultrasound, computed tomography (CT and magnetic resonance imaging of the abdomen showed a massive septated cystic lesion filling the entire abdomen with a significant mass effect on surrounding structures. Origin of the lesion was unclear and diagnosis included a giant mesenteric or duplication cyst, massive gallbladder with hydrops, biliary cystadenoma and giant choledochal cyst, among others. Final diagnosis was a Type IA choledochal cyst with massive asymmetric cystic dilatation of the extra-hepatic segments of the left hepatic duct with asymmetric dilatation of the right hepatic duct. Patient had an uneventful recovery after resection of the entire extrahepatic cyst and Roux-en-Y hepaticojejunostomy at the level of the hilum. In this article, we correlate CT and MRI findings to gross and histopathological findings of this giant Todani′s Type IA choledochal cyst.
Multipole Analysis of Circular Cylindircal Magnetic Systems
Selvaggi, Jerry P. [Rensselaer Polytechnic Inst., Troy, NY (United States)
2005-12-01
This thesis deals with an alternate method for computing the external magnetic field from a circular cylindrical magnetic source. The primary objective is to characterize the magnetic source in terms of its equivalent multipole distribution. This multipole distribution must be valid at points close to the cylindrical source and a spherical multipole expansion is ill-equipped to handle this problem; therefore a new method must be introduced. This method, based upon the free-space Green's function in cylindrical coordinates, is developed as an alternative to the more familiar spherical harmonic expansion. A family of special functions, called the toroidal functions or Q-functions, are found to exhibit the necessary properties for analyzing circular cylindrical geometries. In particular, the toroidal function of zeroth order, which comes from the integral formulation of the free-space Green's function in cylindrical coordinates, is employed to handle magnetic sources which exhibit circular cylindrical symmetry. The toroidal functions, also called Q-functions, are the weighting coefficients in a ''Fourier series-like'' expansion which represents the free-space Green's function. It is also called a toroidal expansion. This expansion can be directly employed in electrostatic, magnetostatic, and electrodynamic problems which exhibit cylindrical symmetry. Also, it is shown that they can be used as an alternative to the Elliptic integral formulation. In fact, anywhere that an Elliptic integral appears, one can replace it with its corresponding Q-function representation. A number of problems, using the toroidal expansion formulation, are analyzed and compared to existing known methods in order to validate the results. Also, the equivalent multipole distribution is found for most of the solved problems along with its corresponding physical interpretation. The main application is to characterize the external magnetic field due to a six
Modeling and Optimizing RF Multipole Ion Traps
Fanghaenel, Sven; Asvany, Oskar; Schlemmer, Stephan
2016-06-01
Radio frequency (rf) ion traps are very well suited for spectroscopy experiments thanks to the long time storage of the species of interest in a well defined volume. The electrical potential of the ion trap is determined by the geometry of its electrodes and the applied voltages. In order to understand the behavior of trapped ions in realistic multipole traps it is necessary to characterize these trapping potentials. Commercial programs like SIMION or COMSOL, employing the finite difference and/or finite element method, are often used to model the electrical fields of the trap in order to design traps for various purposes, e.g. introducing light from a laser into the trap volume. For a controlled trapping of ions, e.g. for low temperature trapping, the time dependent electrical fields need to be known to high accuracy especially at the minimum of the effective (mechanical) potential. The commercial programs are not optimized for these applications and suffer from a number of limitations. Therefore, in our approach the boundary element method (BEM) has been employed in home-built programs to generate numerical solutions of real trap geometries, e.g. from CAD drawings. In addition the resulting fields are described by appropriate multipole expansions. As a consequence, the quality of a trap can be characterized by a small set of multipole parameters which are used to optimize the trap design. In this presentation a few example calculations will be discussed. In particular the accuracy of the method and the benefits of describing the trapping potentials via multipole expansions will be illustrated. As one important application heating effects of cold ions arising from non-ideal multipole fields can now be understood as a consequence of imperfect field configurations.
Gao, Y.; Wang, X.; Xie, L.; Hu, Z.; Lin, H.; Zhou, Z.; Nan, T.; Yang, X.; Howe, B. M.; Jones, J. G.; Brown, G. J.; Sun, N. X.
2016-06-01
It has been challenging to achieve combined strong magnetoelectric coupling and narrow ferromagnetic resonance (FMR) linewidth in multiferroic heterostructures. Electric field induced large effective field of 175 Oe and narrow FMR linewidth of 40 Oe were observed in FeCoSiB/Si/SiO2/PMN-PT heterostructures with substrate clamping effect minimized through removing the Si substrate. As a comparison, FeCoSiB/PMN-PT heterostructures with FeCoSiB film directly deposited on PMN-PT showed a comparable voltage induced effective magnetic field but a significantly larger FMR linewidth of 283 Oe. These multiferroic heterostructures exhibiting combined giant magnetoelectric coupling and narrow ferromagnetic resonance linewidth offer great opportunities for integrated voltage tunable RF magnetic devices.
Petri Honkanen
2014-01-01
Full Text Available Background: Better diagnostic tools to identify rupture-prone saccular intracranial aneurysms (sIA are needed. Inflammation and luminal thrombus associate with degeneration and rupture of the sIA wall. Iron-uptake has been detected in the inflammatory cells of the sIA wall and thrombus is the likely source of this iron. We investigated ex vivo the use of magnetic resonance imaging (MRI to detect iron accumulation and luminal thrombus in giant sIAs. Methods: Giant sIAs (n = 3 were acquired from microsurgical operations, fixed with formalin, embedded in agar and imaged at 4.7T. Samples were sectioned maintaining the orientation of the axial plane of MRI scans, and stained (hematoxylin-eosin and Prussian blue. Results: All three giant sIAs showed a degenerated hypocellular wall with both mural and adventitial iron accumulation and displayed different degrees of luminal thrombus formation and thrombus organization. Signal intensity varied within the same sIA wall and associated with iron accumulation in all tested sequences. Wall areas with iron accumulation had significantly lower signal to noise ratio (SNR compared with areas without iron accumulation (P = 0.002. Fresh and organizing thrombus differed in their MRI presentation and differed in signal intensity of the aneurysm wall (P = 0.027. Conclusion: MRI can detect ex vivo the accumulation of iron in giant sIA wall, as well as fresh and organizing luminal thrombus. These features have been previously associated with fragile, rupture-prone aneurysm wall. Further studies of iron accumulation as a marker of rupture-prone aneurysm wall are needed.
Pygmy dipole resonance and dipole polarizability in 90Zr
Iwamoto, C.; Tamii, A.; Utsunomiya, H.; Akimune, H.; Nakada, H.; Shima, T.; Hashimoto, T.; Yamagata, T.; Kawabata, T.; Fujita, Y.; Matsubara, H.; Suzuki, T.; Fujita, H.; Shimbara, Y.; Nagashima, M.; Sakuda, M.; Mori, T.; Izumi, T.; Okamoto, A.; Kondo, T.; Lui, T.-W.; Bilgier, B.; Kozer, H. C.; Hatanaka, K.
2014-05-01
Electric dipole (E1) reduced transition probability B(E1) of 90Zr was obtained by the inelastic proton scattering near 0 degrees using a 295 MeV proton beam and multipole decomposition analysis of the angular distribution by the distorted-wave Born approximation with the Hartree-Fock plus random-phase approximation model and inclusion of El Coulomb excitation, and the E1 strength of the pygmy dipole resonance was found in the vicinity of the neutron threshold in the low-energy tail of the giant dipole resonance. Using the data, we plan to determine the precise dipole polarizability αD which is defined as an inversely energy-weighted sum value of the elecrric dipole strength. The dipole polarizability is expected to constrain the symmetry energy term of the neutron matter equation of state. Thus systematical measurement of the dipole polarizability is important.
Pygmy dipole resonance and dipole polarizability in {sup 90}Zr
Iwamoto, C.; Tamii, A.; Shima, T.; Hashimoto, T.; Suzuki, T.; Fujita, H.; Hatanaka, K. [Research Center for Nuclear Physics, Osaka University, Ibaraki, Osaka 567-0047 (Japan); Utsunomiya, H.; Akimune, H.; Yamagata, T.; Okamoto, A.; Kondo, T. [Department of Physics, Konan University, Okamoto 8-9-1, Higashinada, Kobe 658-8501 (Japan); Nakada, H. [Department of Physics, Graduate School of Science, Chiba University, Yayoi-cho 1-33, Inage, Chiba 263-8522 (Japan); Kawabata, T. [Department of Physics, Kyoto University, Kyoto 606-8502 (Japan); Fujita, Y. [Department of Physics, Osaka University, Toyonaka, Osaka, 560-0043 (Japan); Matsubara, H. [RIKEN Nishina Center, Wako, Saitama 351-0198 (Japan); Shimbara, Y.; Nagashima, M. [Department of Physics, Niigata University, Niigata 950-21-2 (Japan); Sakuda, M.; Mori, T. [Department of Physics, Okayama University, Okayama 900-0082 (Japan); and others
2014-05-02
Electric dipole (E1) reduced transition probability B(E1) of {sup 90}Zr was obtained by the inelastic proton scattering near 0 degrees using a 295 MeV proton beam and multipole decomposition analysis of the angular distribution by the distorted-wave Born approximation with the Hartree-Fock plus random-phase approximation model and inclusion of El Coulomb excitation, and the E1 strength of the pygmy dipole resonance was found in the vicinity of the neutron threshold in the low-energy tail of the giant dipole resonance. Using the data, we plan to determine the precise dipole polarizability α{sub D} which is defined as an inversely energy-weighted sum value of the elecrric dipole strength. The dipole polarizability is expected to constrain the symmetry energy term of the neutron matter equation of state. Thus systematical measurement of the dipole polarizability is important.
Multipole plasmons and their disappearance in few-nanometre silver nanoparticles
Raza, Søren; Kadkhodazadeh, Shima; Christensen, Thomas
2015-01-01
Electron energy-loss spectroscopy can be used for detailed spatial and spectral characterization of optical excitations in metal nanoparticles. In previous electron energy-loss experiments on silver nanoparticles with radii smaller than 20 nm, only the dipolar surface plasmon resonance was assumed...... theoretical predictions. Unlike in optical spectra, multipole surface plasmons are important in electron energy-loss spectra even of ultrasmall metallic nanoparticles....
Multipole Traps as Tools in Environmental Studies
Mihalcea, Bogdan M; Giurgiu, Liviu C; Groza, Andreea; Surmeian, Agavni; Ganciu, Mihai; Filinov, Vladimir; Lapitsky, Dmitry; Deputatova, Lidiya; Vasilyak, Leonid; Pecherkin, Vladimir; Vladimirov, Vladimir; Syrovatka, Roman
2015-01-01
Trapping of microparticles, nanoparticles and aerosols is an issue of major interest for physics and chemistry. We present a setup intended for microparticle trapping in multipole linear Paul trap geometries, operating under Standard Ambient Temperature and Pressure (SATP) conditions. A 16-electrode linear trap geometry has been designed and tested, with an aim to confine a larger number of particles with respect to quadrupole traps and thus enhance the signal to noise ratio, as well as to study microparticle dynamical stability in electrodynamic fields. Experimental tests and numerical simulations suggest that multipole traps are very suited for high precision mass spectrometry measurements in case of different microparticle species or to identify the presence of certain aerosols and polluting agents in the atmosphere. Particle traps represent versatile tools for environment monitoring or for the study of many-body Coulomb systems and dusty plasmas.
Multipole invariants and non-Gaussianity
Land, K; Land, Kate; Magueijo, Joao
2004-01-01
We propose a framework for separating the information contained in the CMB multipoles, $a_{\\ell m}$, into its algebraically independent components. Thus we cleanly separate information pertaining to the power spectrum, non-Gaussianity and preferred axis effects. The formalism builds upon the recently proposed multipole vectors (Copi, Huterer & Starkman 2003; Schwarz & al 2004; Katz & Weeks 2004), and we elucidate a few features regarding these vectors, namely their lack of statistical independence for a Gaussian random process. In a few cases we explicitly relate our proposed invariants to components of the $n$-point correlation function (power spectrum, bispectrum). We find the invariants' distributions using a mixture of analytical and numerical methods. We also evaluate them for the co-added WMAP first year map.
Multipole solutions in metric-affine gravity
Socorro, J; Macías, A; Mielke, E W; Socorro, José; Lämmerzahl, Claus; Macías, Alfredo; Mielke, Eckehard W.
1998-01-01
Above Planck energies, the spacetime might become non--Riemannian, as it is known fron string theory and inflation. Then geometries arise in which nonmetricity and torsion appear as field strengths, side by side with curvature. By gauging the affine group, a metric affine gauge theory emerges as dynamical framework. Here, by using the harmonic map ansatz, a new class of multipole like solutions in the metric affine gravity theory (MAG) is obtained.
Poloidal OHMIC heating in a multipole
Holly, D.J.
1982-01-01
The feasibility of using poloidal currents to heat plasmas confined by a multipole field has been examined experimentaly in Tokapole II. The machine is operated as a toroidal octupole, with a time-varying toroidal magnetic field driving poloidal plasma currents I/sub plasma/ - 20 kA to give densities n/sub e/ - 10/sup 13/ cm/sup -3/ and temperatures T/sub e/ - 30 eV.
Optimization of RF multipole ion trap geometries
Fanghänel, Sven; Asvany, Oskar; Schlemmer, Stephan
2017-02-01
Radio-frequency (rf) traps are ideal places to store cold ions for spectroscopic experiments. Specific multipole configurations are suited best for different applications but have to be modified to allow e.g. for a proper overlap of a laser beam waist with the ion cloud. Therefore the corresponding trapping fields should be shaped accordingly. To achieve this goal highly accurate electrical potentials of rf multipole traps and the resulting effective trapping potentials are calculated using the boundary element method (BEM). These calculations are used to evaluate imperfections and to optimize the field geometry. For that purpose the complex fields are reduced to a small set of multipole expansion coefficients. Desirable values for these coefficients are met by systematic changes of real trap dimensions from CAD designs. The effect of misalignment of a linear quadrupole, the optimization of an optically open Paul trap, the influence of steering electrodes (end electrode and ring electrode) on a 22-pole ion trap and the effect of the micro motion on the lowest reachable temperatures in such a trap are discussed.
Least Square Approximation by Linear Combinations of Multi(Poles).
1983-04-01
ID-R134 069 LEAST SQUARE APPROXIMATION BY LINEAR COMBINATIONS OF i/i MULTI(POLES). 1U OHIO STATE UNIV COLUMBUS DEPT OF GEODETIC SCIENCE AND SURVEY...TR-83-0 117 LEAST SQUARE APPROXIMATION BY LINEAR COMBINATIONS OF (MULTI)POLES WILLI FREEDEN DEPARTMENT OF GEODETIC SCIENCE AND SURVEYING THE OHIO...Subtitle) S. TYPE OF REPORT & PERIOD COVERED LEAST SQUARE APPROXIMATION BY LINEAR Scientific Report No. 3 COMBINATIONS OF (MULTI)POLES 6. PERFORMING ORG
2016-06-06
1 Giant electric field control of magnetism and narrow ferromagnetic resonance linewidth in FeCoSiB/Si/SiO2/PMN-PT multiferroic heterostructures...coupling and narrow ferromagnetic resonance (FMR) linewidth in multiferroic heterostructures. Electric field induced large effective field of 175Oe...in which the electric field applied to the piezoelectric layer produces a mechanical deformation that couples to the magnetic film, and hence induces
Complex space multipole theory for scattering and diffraction problems
Lindell, Ismo V.; Nikoskinen, Keijo I.
1987-01-01
Classical multipole theory can be extended to multipoles located in complex space and applied in scattering and diffraction problems with the advantage that, if the point of the multipole is correctly chosen, the first term may give an order of magnitude better approximation to the source than when the multipole is in real space. The basic theory, given elsewhere, is presented here in a more straightforward manner and the improvement in radiation pattern is demonstrated for sources of constant polarization. Applications on scattering by spheroidal dielectric bodies and diffraction by a dielectric half-space are discussed.
Biswal, S K
2014-01-01
We study the isoscalar giant monopole resonance for drip-lines and super heavy nuclei in the frame work of a relativistic mean field theory with scaling approach. The well known extended Thomas-Fermi approximation in the non-linear $\\sigma$-$\\omega$ model is used to estimate the giant monopole excitation energy for some selected light spherical nuclei starting from the region of proton to neutron drip-lines. The application is extended to super heavy region for Z=114 and 120, which are predicted by several models as the next proton magic number beyond Z=82. We compared the excitation energy obtained by four successful force parameters NL1, NL3, NL3$^*$ and FSUGold. The monopole energy decreases toward the proton and neutron drip-lines in an isotopic chain for lighter mass nuclei contrary to a monotonous decrease for super heavy isotopes. The maximum and minimum monopole excitation energies are obtained for nuclei with minimum and maximum isospin, respectively in an isotopic chain.
Patel, D; Fujiwara, M; Akimune, H; Berg, G P A; Harakeh, M N; Itoh, M; Kawabata, T; Kawase, K; Nayak, B K; Ohta, T; Ouchi, H; Piekarewicz, J; Uchida, M; Yoshida, H P; Yosoi, M
2012-01-01
The isoscalar giant monopole resonance (ISGMR) in even-A Cd isotopes has been studied by inelastic ${\\alpha}$-scattering at 100 MeV/u and at extremely forward angles, including 0deg. The asymmetry term in the nuclear incompressibility extracted from the ISGMR in Cd isotopes is found to be $K_{\\tau} = -555 \\pm 75$ MeV, confirming the value previously obtained from the Sn isotopes. ISGMR strength has been computed in relativistic RPA using NL3 and FSUGold effective interactions. Both models significantly overestimate the centroids of the ISGMR strength in the Cd isotopes. Combined with other recent theoretical effort, the question of the "softness" of the open-shell nuclei in the tin region remains open still.
Patel, D. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Garg, U., E-mail: garg@nd.edu [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Fujiwara, M. [Research Center for Nuclear Physics, Osaka University, Osaka 567-0047 (Japan); Akimune, H. [Department of Physics, Konan University, Kobe 568-8501 (Japan); Berg, G.P.A. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Harakeh, M.N. [Kernfysisch Versneller Instituut, University of Groningen, 9747 AA Groningen (Netherlands); Itoh, M. [Cyclotron and Radioisotope Center, Tohoku University, Sendai 980-8578 (Japan); Kawabata, T. [Center for Nuclear Studies, University of Tokyo, Tokyo 113-0033 (Japan); Kawase, K. [Institute of Scientific and Industrial Research, Osaka University, Osaka 567-0047 (Japan); Nayak, B.K. [Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Ohta, T. [Research Center for Nuclear Physics, Osaka University, Osaka 567-0047 (Japan); Ouchi, H. [Cyclotron and Radioisotope Center, Tohoku University, Sendai 980-8578 (Japan); Piekarewicz, J. [Department of Physics, Florida State University, Tallahassee, FL 32306 (United States); Uchida, M. [Department of Physics, Tokyo Institute of Technology, Tokyo 152-8850 (Japan); Yoshida, H.P. [Cyclotron and Radioisotope Center, Tohoku University, Sendai 980-8578 (Japan); Yosoi, M. [Research Center for Nuclear Physics, Osaka University, Osaka 567-0047 (Japan)
2012-12-05
The isoscalar giant monopole resonance (ISGMR) in even-A Cd isotopes has been studied by inelastic {alpha}-scattering at 100 MeV/u and at extremely forward angles, including 0 Degree-Sign . The asymmetry term in the nuclear incompressibility extracted from the ISGMR in Cd isotopes is found to be K{sub {tau}}=-555{+-}75 MeV, confirming the value previously obtained from the Sn isotopes. ISGMR strength has been computed in relativistic RPA using NL3 and FSUGold effective interactions. Both models significantly overestimate the centroids of the ISGMR strength in the Cd isotopes. Combined with other recent theoretical effort, the question of the 'softness' of the open-shell nuclei in the tin region remains open still.
Barlini, S.; Kravchuk, V. L.; Wieland, O.; Bracco, A.; Gramegna, F.; Airoldi, A.; Benzoni, G.; Blasi, N.; Brambilla, S.; Brekiesz, M.; Bruno, M.; Camera, F.; Casini, G.; Chiari, M.; D'Agostino, M.; De Sanctis, J.; Geraci, E.; Kmiecik, M.; Lanchais, A.; Leoni, S.; Maj, A.; Mastinu, P. F.; Million, B.; Moroni, A.; Nannini, A.; Ordine, A.; Sacchi, R.; Vannini, G.
2006-08-01
Recent measurements have been performed at the National Laboratoty of Legnaro using mass-symmetric (400, 500 MeV 64Ni + 68Zn) and mass-asymmetric (250 MeV 16O + 116Sn) entrance channel reactions to form 132Ce compound nucleus at different excitation energies (E*=150, 200 and 200 MeV, respectively). The decay of the composite system has been followed studying the γ-rays and Light Charged Particles (LCP) spectra emitted in coincidence with the Evaporation Residues (ER). In this way the emission mechanism of the LCP, depending on the mass-asymmetry at the entrance channel and on the projectile energy, and the results of the Full Width Half-Maximum (FWHM) of the Giant Dipole Resonance as a function of the nuclear temperature have been studied.
Wu, Xiongwu; Pickard, Frank C.; Brooks, Bernard R.
2016-10-01
Isotropic periodic sum (IPS) is a method to calculate long-range interactions based on the homogeneity of simulation systems. By using the isotropic periodic images of a local region to represent remote structures, long-range interactions become a function of the local conformation. This function is called the IPS potential; it folds long-ranged interactions into a short-ranged potential and can be calculated as efficiently as a cutoff method. It has been demonstrated that the IPS method produces consistent simulation results, including free energies, as the particle mesh Ewald (PME) method. By introducing the multipole homogeneous background approximation, this work derives multipole IPS potentials, abbreviated as IPSMm, with m being the maximum order of multipole interactions. To efficiently calculate the multipole interactions in Cartesian space, we propose a vector relation that calculates a multipole tensor as a dot product of a radial potential vector and a directional vector. Using model systems with charges, dipoles, and/or quadrupoles, with and without polarizability, we demonstrate that multipole interactions of order m can be described accurately with the multipole IPS potential of order 2 or m - 1, whichever is higher. Through simulations with the multipole IPS potentials, we examined energetic, structural, and dynamic properties of the model systems and demonstrated that the multipole IPS potentials produce very similar results as PME with a local region radius (cutoff distance) as small as 6 Å.
Kelvin transformation and inverse multipoles in electrostatics
Amaral, R L P G; Lemos, N A
2016-01-01
The inversion in the sphere or Kelvin transformation, which exchanges the radial coordinate for its inverse, is used as a guide to relate distinct electrostatic problems with dual features. The exact solution of some nontrivial problems are obtained through the mapping from simple highly symmetric systems. In particular, the concept of multipole expansion is revisited from a point of view opposed to the usual one: the sources are distributed in a region far from the origin while the electrostatic potential is described at points close to it.
Multipole stack for the 4 rings of the PS Booster
1976-01-01
The PS Booster (originally 800 MeV, now 1.4 GeV) saw first beam in 1972, routine operation began in 1973. The strive for ever higher intensities required the addition of multipoles. Manufacture of 8 stacks of multipoles was launched in 1974, for installation in 1976. For details, see 7511120X.
Reflection and refraction of multipole radiation by an interface.
Arnoldus, Henk F
2005-01-01
Reflection and refraction of electromagnetic multipole radiation by an interface is studied. The multipole can be electric or magnetic and is of arbitrary order (dipole, quadrupole). From the angular spectrum representation of the radiation emitted by the multipole, I have obtained the angular spectrum representations of the reflected and transmitted fields, which involve the Fresnel reflection and transmission coefficients. The intensity distribution in the far field is evaluated with the method of stationary phase. The result is very simple in appearance and can be expressed in terms of two auxiliary functions of a complex variable. By exchanging the Fresnel coefficients for s and p polarization, the result for an electric multipole can be obtained from the result for a magnetic multipole.
A fast multipole transformation for global climate calculations
Holmes, J.A.; Wang, Z.; Drake, J.B.; Lyon, B.F.; Chen, W.T.
1996-01-01
A fast multipole transformation is adapted to the evaluation of summations that occur in global climate calculations when transforming between spatial and spherical harmonic representations. For each summation, the timing of the fast multipole transformation scales linearly with the number of latitude gridpoints, but the timing for direct evaluations scales quadratically. In spite of a larger computational overhead, this scaling advantage renders the fast multipole method faster than direct evaluation for transformations involving greater than approximately 300 to 500 gridpoints. Convergence of the fast multipole transformation is accurate to machine precision. As the resolution in global climate calculations continues to increase, an increasingly large fraction of the computational work involves the transformation between spatial and spherical harmonic representations. The fast multipole transformation offers a significant reduction in computational time for these high-resolution cases.
Microscopic Theory of Multipole Ordering in f-Electron Systems
Takashi Hotta
2012-01-01
Full Text Available A microscopic framework to determine multipole ordering in f-electron systems is provided on the basis of the standard quantum field theory. For the construction of the framework, a seven-orbital Hubbard Hamiltonian with strong spin-orbit coupling is adopted as a prototype model. A type of multipole and ordering vector is determined from the divergence of multipole susceptibility, which is evaluated in a random phase approximation. As an example of the application of the present framework, a multipole phase diagram on a three-dimensional simple cubic lattice is discussed for the case of n=2, where n denotes the average f-electron number per site. Finally, future problems concerning multipole ordering and fluctuations are briefly discussed.
The Multipole Vectors of WMAP, and their frames and invariants
Land, K; Land, Kate; Magueijo, Joao
2005-01-01
We investigate the Statistical Isotropy and Gaussianity of the CMB fluctuations, using a set of multipole vector functions capable of separating these two issues. In general a multipole is broken into a frame and $2\\ell-3$ ordered invariants. The multipole frame is found to be suitably sensitive to galactic cuts. We then apply our method to real WMAP datasets; a coadded masked map, the Internal Linear Combinations map, and Wiener filtered and cleaned maps. Taken as a whole, multipoles in the range $\\ell=2-10$ or $\\ell=2-20$ show consistency with statistical isotropy, as proved by the Kolmogorov test applied to the frame's Euler angles. This result in {\\it not} inconsistent with previous claims for a preferred direction in the sky for $\\ell=2,...5$. The multipole invariants also show overall consistency with Gaussianity apart from a few anomalies of limited significance (98%), listed at the end of this paper.
Multipole Stack for the 800 MeV PS Booster
1975-01-01
The 800 MeV PS Booster had seen first beam in its 4 superposed rings in 1972, routine operation began in 1973. In the strive for ever higher beam intensities, the need for additional multipole lenses became evident. After detailed studies, the manufacture of 8 stacks of multipoles was launched in 1974. Each stack consists of 4 superposed multipoles and each multipole has 4 concentric shells. From the innermost to the outermost shell, Type A contains octupole, skew-octupole, sextupole, skew-sextupole. Type B contains skew-octupole, skew-sextupole, vertical dipole, horizontal dipole. Completion of installation in 1976 opened the way to higher beam intensities. M. Battiaz is seen here with a multipole stack and its many electrical connections.
Multipole charge conservation and implications on electromagnetic radiation
Seraj, Ali
2016-01-01
It is shown that conserved charges associated with a specific subclass of gauge symmetries of Maxwell electrodynamics are proportional to the well known electric multipole moments. The symmetries are residual gauge transformations surviving after fixing the Lorenz gauge, and have nontrivial charge. These "Multipole charges" receive contributions both from the charged matter and electromagnetic fields. The former is nothing but the electric multipole moment of the source. In a stationary configuration, there is a novel equipartition relation between the two contributions. The multipole charge, while conserved, can freely interpolate between the source and the electromagnetic field, and therefore can be propagated with the radiation. Using the multipole charge conservation, we obtain infinite number of constraints over the radiation produced by the dynamics of charged matter.
Application of EEG multipole model in the diagnosis of Alzheimer's disease
无
2008-01-01
In order to find the electroencephalogram (EEG) characteristic parameters typical of Alzheimer's disease (AD) and explore an effective diagnostic method, a new mobile current multipole model was proposed to simulate the AD patient's cortical dipole source activities.The indicators of goodness of fit (GOF) and DtononD (DD) were calculated from EEG samples to evaluate the performance of this model. Relevant results showed that this multipole model with higher GOF values and larger DD change well fitted the pathological electrical activities of cortical neurons aroused by AD's extended sulcus and gyrus in the cerebral cortex. Meanwhile, the products of DD mean & standard variance were found in a clear linear correlation with the diagnostic data of mini-mental state examination (MMSE) used in AD clinics. Furthermore, by tracing this multipole model's indicators in typical patients and contrasting with the functional magnetic resonance image (fMRI) as AD progressed, we suggested that the DD index may be suitable for monitoring the AD developments as a new diagnostic parameter.
[Giant retroperitoneal liposarcoma].
Mezzour, Mohamed Hicham; El Messaoudi, Yasser Arafat; Fekak, Hamid; Rabii, Redouane; Marnissi, Farida; Karkouri, Mehdi; Salam, Siham; Iraki, Moulay Ahmed; Joual, Abdenbi; Meziane, Fathi
2006-02-01
The authors report a case of giant retroperitoneal liposarcoma. The diagnosis was suspected after scanography and magnetic resonance imaging and confirmed by the histological analysis of the extracted piece after surgical treatment. Postoperative evolution was favourable after one year without recurrence or distant metastasis. The authors discuss the pathologic and therapeutic aspects and the prognosis of retroperitoneal liposarcoma.
Limitation of Multipoles in BOSS DR12 results
Lee, Seokcheon
2016-01-01
Recently, the power spectrum (PS) multipoles using the Baryon Oscillation Spectroscopic Survey (BOSS) Data Release 12 (DR12) sample are analyzed \\cite{160703150}. Even though the based model for the analysis is the so-called TNS quasi-linear model including the multipole up to the eighth order in the window function \\cite{TNS}, the analysis provides the multipoles up to the hexadecapole. Thus, one might be able to recover the galaxy PS by using the combination of multipoles to investigate the cosmology \\cite{0407214}. We provide the analytic form of this combination of multipoles of the quasi-linear PS including the Fingers of God (FoG) effect to recover the PS at the linear regime. In order to confirm the consistency of the multipole data, we compare the multipole ratios of the linear theory including the FoG effect with those of observation. The data of the ratio of quadrupole to monopole is consistent with that of the linear theory prediction even though the current observational error is too large to dist...
Multipole moments of bumpy black holes
Vigeland, Sarah J
2010-01-01
General relativity predicts the existence of black holes, compact objects whose spacetimes depend on only their mass and spin (the famous "no hair" theorem). As various observations probe deeper into the strong fields of black hole candidates, it is becoming possible to test this prediction. Previous work suggested that such tests can be performed by measuring whether the multipolar structure of black hole candidates has the form that general relativity demands, and introduced a family of "bumpy black hole" spacetimes to be used for making these measurements. These spacetimes are black holes with the "wrong" multipoles, where the deviation from general relativity depends on the spacetime's "bumpiness." In this paper, we show how to compute the Geroch-Hansen moments of a bumpy black hole, demonstrating that there is a clean mapping between the deviations used in the bumpy black hole formalism and the Geroch-Hansen moments. We also extend our previous results to define bumpy black holes whose {\\it current} mome...
Multipole Monolithic Surface Acoustic Wave (SAW) Resonator Filters.
1982-04-01
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Process Diagnostics and Monitoring Using the Multipole Resonance Probe (MRP)
Harhausen, J.; Awakowicz, P.; Brinkmann, R. P.; Foest, R.; Lapke, M.; Musch, T.; Mussenbrock, T.; Oberrath, J.; Ohl, A.; Rolfes, I.; Schulz, Ch.; Storch, R.; Styrnoll, T.
2011-10-01
In this contribution we present the application of the MRP in an industrial plasma ion assisted deposition (PIAD) chamber (Leybold optics SYRUS-pro). The MRP is a novel plasma diagnostic which is suitable for an industrial environment - which means that the proposed method is robust, calibration free, and economical, and can be used for ideal and reactive plasmas alike. In order to employ the MRP as process diagnostics we mounted the probe on a manipulator to obtain spatially resolved information on the electron density and temperature. As monitoring tool the MRP is installed at a fixed position. Even during the deposition process it provides stable measurement results while other diagnostic methods, e.g. the Langmuir probe, may suffer from dielectric coatings. In this contribution we present the application of the MRP in an industrial plasma ion assisted deposition (PIAD) chamber (Leybold optics SYRUS-pro). The MRP is a novel plasma diagnostic which is suitable for an industrial environment - which means that the proposed method is robust, calibration free, and economical, and can be used for ideal and reactive plasmas alike. In order to employ the MRP as process diagnostics we mounted the probe on a manipulator to obtain spatially resolved information on the electron density and temperature. As monitoring tool the MRP is installed at a fixed position. Even during the deposition process it provides stable measurement results while other diagnostic methods, e.g. the Langmuir probe, may suffer from dielectric coatings. Funded by the German Ministry for Education and Research (BMBF, Fkz. 13N10462).
Krasznahorkay, A; Csige, L; Eriksen, T K; Giacoppo, F; Görgen, A; Hagen, T W; Harakeh, M N; Julin, R; Koehler, P; Paar, N; Siem, S; Stuhl, L; Tornyi, T; Vretenar, D
2013-01-01
The 208Pb(p,ngamma p)207Pb reaction at a beam energy of 30 MeV has been used to excite the anti-analog of the giant dipole resonance (AGDR) and to measure its gamma-decay of to the isobaric analog state. The energy of the transition has also been calculated with the self-consistent relativistic random-phase approximation (RRPA), and found to be linearly correlated to the predicted value of the neutron-skin thickness (DR_pn). By comparing the theoretical results with the measured transition energy, the value of 0.190 +- 0.028 fm has been determined for DR_pn of 208Pb, in agreement with previous experimental results. The AGDR excitation energy has also been used to calculate the symmetry energy at saturation (J=32.7+- 0.6 MeV) and the slope of the symmetry energy (L=49.7 +- 4.4 MeV), resulting in more stringent constraints than most of the previous studies.
Loi, Shyeh Tjing; Papaloizou, John C. B.
2017-05-01
Stars are self-gravitating fluids in which pressure, buoyancy, rotation and magnetic fields provide the restoring forces for global modes of oscillation. Pressure and buoyancy energetically dominate, while rotation and magnetism are generally assumed to be weak perturbations and often ignored. However, observations of anomalously weak dipole mode amplitudes in red giant stars suggest that a substantial fraction of these are subject to an additional source of damping localized to their core region, with indirect evidence pointing to the role of a deeply buried magnetic field. It is also known that in many instances, the gravity-mode character of affected modes is preserved, but so far, no effective damping mechanism has been proposed that accommodates this aspect. Here we present such a mechanism, which damps the oscillations of stars harbouring magnetised cores via resonant interactions with standing Alfvén modes of high harmonic index. The damping rates produced by this mechanism are quantitatively on par with those associated with turbulent convection, and in the range required to explain observations, for realistic stellar models and magnetic field strengths. Our results suggest that magnetic fields can provide an efficient means of damping stellar oscillations without needing to disrupt the internal structure of the modes, and lay the groundwork for an extension of the theory of global stellar oscillations that incorporates these effects.
Waetzig, Gregory R; Horrocks, Gregory A; Jude, Joshua W; Zuin, Lucia; Banerjee, Sarbajit
2016-01-14
Design rules for X-ray phosphors are much less established as compared to their optically stimulated counterparts owing to the absence of a detailed understanding of sensitization mechanisms, activation pathways and recombination channels upon high-energy excitation. Here, we demonstrate a pronounced modulation of the X-ray excited photoluminescence of Tb(3+) centers upon excitation in proximity to the giant resonance of the host Gd(3+) ions in solid-solution Gd1-xTbxOCl nanocrystals prepared by a non-hydrolytic cross-coupling method. The strong suppression of X-ray excited optical luminescence at the giant resonance suggests a change in mechanism from multiple exciton generation to single thermal exciton formation and Auger decay processes. The solid-solution Gd1-xTbxOCl nanocrystals are further topotactically transformed with retention of a nine-coordinated cation environment to solid-solution Gd1-xTbxF3 nanocrystals upon solvothermal treatment with XeF2. The metastable hexagonal phase of GdF3 can be stabilized at room temperature through this topotactic approach and is transformed subsequently to the orthorhombic phase. The fluoride nanocrystals indicate an analogous but blue-shifted modulation of the X-ray excited optical luminescence of the Tb(3+) centers upon X-ray excitation near the giant resonance of the host Gd(3+) ions.
Zhang, Ke; Wang, Hui; Gan, Zhikai; Zhou, Peiqi; Mei, Chunlian; Huang, Xu; Xia, Yuxing
2016-03-01
We report substantially enlarged lateral photovoltaic effect (LPE) in the ZnO/Ag/Si nanostructures. The maximum LPE sensitivity (55.05 mv/mm) obtained in this structure is about seven times larger than that observed in the control sample (7.88 mv/mm) of ZnO/Si. We attribute this phenomenon to the strong localized surface plasmon resonances (LSPRs) induced by nano Ag semicontinuous films. Quite different from the traditional LPE in PN junction type structures, in which light-generated carriers contributed to LPE merely depends on direct excitation of light in semiconductor, this work firstly demonstrates that, by introducing a super thin metal Ag in the interface between two different kinds of semiconductors, the nanoscale Ag embedded in the interface will produce strong resonance of localized field, causing extra intraband excitation, interband excitation and an enhanced direct excitation. As a consequence, these LSPRs dominated contributions harvest much more carriers, giving rise to a greatly enhanced LPE. In particular, this LSPRs-driven mechanism constitutes a sharp contrast to the traditional LPE operation mechanism. This work suggests a brand new LSPRs approach for tailoring LPE-based devices and also opens avenues of research within current photoelectric sensors area.
Yong, Z.; Trevisanutto, P. E.; Chiodo, L.; Santoso, I.; Barman, A. R.; Asmara, T. C.; Dhar, S.; Kotlov, A.; Terentjevs, A.; Della Sala, F.; Olevano, V.; Rübhausen, M.; Venkatesan, T.; Rusydi, A.
2016-05-01
Titanium dioxide (TiO2) has rich physical properties with potential implications for both fundamental physics and new applications. To date, the main focus of applied research is to tune its optical properties, which is usually done via doping and/or nanoengineering. However, understanding the role of d electrons in materials and possible functionalization of d -electron properties are still major challenges. Herewith, within a combination of an innovative experimental technique, high-energy optical conductivity, and state-of-the-art ab initio electronic structure calculations, we report an emerging, novel resonant exciton in the deep ultraviolet region of the optical response. The resonant exciton evolves upon low-concentration Ta substitution in anatase TiO2 films. It is surprisingly robust and related to strong electron-electron and electron-hole interactions. The d - and f -orbital localization, due to Ta substitution, plays an unexpected role, activating strong electronic correlations and dominating the optical response under photoexcitation. Our results shed light on a new optical phenomenon in anatase TiO2 films and on the possibility of tuning electronic properties by Ta substitution.
Multipole Matrix of Green Function of Laplace Equation
Makuch, K.; Górka, P.
Multipole matrix elements of Green function of Laplace equation are calculated. The multipole matrix elements of Green function in electrostatics describe potential on a sphere which is produced by a charge distributed on the surface of a different (possibly overlapping) sphere of the same radius. The matrix elements are defined by double convolution of two spherical harmonics with the Green function of Laplace equation. The method we use relies on the fact that in the Fourier space the double convolution has simple form. Therefore we calculate the multipole matrix from its Fourier transform. An important part of our considerations is simplification of the three dimensional Fourier transformation of general multipole matrix by its rotational symmetry to the one-dimensional Hankel transformation.
QCD Multipole Expansion and Hadronic Transitions in Heavy Quarkonium Systems
KUANG Yu-ping
2006-01-01
We review the developments of the multipole expansion approach in quantum chromodynamics and its applications to hadronic transitions and some radiative decays of heavy quarkonia.Theoretical predictions are compared with updated experimental results.
Wei, Jingsong [Chinese Academy of Sciences, Shanghai Institute of Optics and Fine Mechanics, Shanghai (China); Zhejiang University, State Key Lab of Silicon Materials, Hangzhou (China); Liu, Jing [Chinese Academy of Sciences, Shanghai Institute of Optics and Fine Mechanics, Shanghai (China); Xiao, Mufei [Universidad Nacional Autonoma de Mexico, Centro de Nanociencias y Nanotecnologia, Apartado Postal 365, Ensenada, Baja California (Mexico)
2011-09-15
Silver-doped silicon thin films were deposited on glass substrate in a co-sputtering procedure. Silver nanoparticles were segregatedly distributed. The nonlinear properties were extracted by z-scan measurements at low laser input power. For about 50% silver density, the nonlinear absorption and refraction coefficients peaked, respectively, at -8.086 x 10{sup -2} m/W and 1.47 x 10{sup -9} m{sup 2}/W, which, with respect to the input intensity, are several orders higher than reported data. The sudden surge of nonlinear responses was explained satisfactorily based on a self-consistent microscopic model calculation for silver clusters. Resonances exist and depend apparently on the laser-modified local cluster concentration. (orig.)
The symmetry group and harmonic potentials of an electrostatic generalized multipole
李钰
1995-01-01
The concept of an electrostatic ordinary multipole has been extended to an electrostatic generalized multipole which consists of a pair of close placed electrostatic ordinary multipole and electrostatic round lens. The definition of the M function for an electrostatic ordinary multipole has been extended to that of the M function for an electrostatic generalized multipole. The relation between the symmetry group of anelectrostaticordinary multipole and that of its corresponding electrostatic generalized multipole, and the relation between their constraint relations among their mth partial harmonic potentials have been derived. By analyzing some important electrostatic generalized multipoles, it is concluded that if an electrostatic deflector-multipole and an electrostatic round lens are placed close to each other , one cannot assert that this combined system can always be treated by the aberration theory of a combined focusing-deflection system.
Scalable fast multipole accelerated vortex methods
Hu, Qi
2014-05-01
The fast multipole method (FMM) is often used to accelerate the calculation of particle interactions in particle-based methods to simulate incompressible flows. To evaluate the most time-consuming kernels - the Biot-Savart equation and stretching term of the vorticity equation, we mathematically reformulated it so that only two Laplace scalar potentials are used instead of six. This automatically ensuring divergence-free far-field computation. Based on this formulation, we developed a new FMM-based vortex method on heterogeneous architectures, which distributed the work between multicore CPUs and GPUs to best utilize the hardware resources and achieve excellent scalability. The algorithm uses new data structures which can dynamically manage inter-node communication and load balance efficiently, with only a small parallel construction overhead. This algorithm can scale to large-sized clusters showing both strong and weak scalability. Careful error and timing trade-off analysis are also performed for the cutoff functions induced by the vortex particle method. Our implementation can perform one time step of the velocity+stretching calculation for one billion particles on 32 nodes in 55.9 seconds, which yields 49.12 Tflop/s.
Rusev, G.Y.
2006-07-01
Investigations of the dipole-strength distributions in {sup 92}Mo, {sup 98}Mo and {sup 100}Mo were carried out by means of the method of nuclear resonance fluorescence. The low-lying excitations in the nuclides {sup 92}Mo, {sup 98}Mo and {sup 100}Mo have been studied in photon-scattering experiments at an electron energy of 6 MeV at the ELBE accelerator and at electron energies from 3.2 to 3.8 MeV at the Dynamitron accelerator. Five levels were observed in {sup 92}Mo. Five levels in {sup 98}Mo and 14 in {sup 100}Mo were identified for the first time in the energy range from 2 to 4 MeV. Dipole-strength distributions up to the neutron-separation energies in the nuclides {sup 92}Mo, {sup 98}Mo and {sup 100}Mo have been investigated at the ELBE accelerator. Because of the possible observation of transitions in the neighboring nuclei produced via ({gamma},n) reaction, additional measurements at electron energies of 8.4 and 7.8 MeV, below the neutron-separation energy, were performed on {sup 98}Mo and {sup 100}Mo, respectively. The number of transitions assigned to {sup 92}Mo, {sup 98}Mo and {sup 100}Mo is 340, 485 and 499, respectively, the main part of them being dipole transitions. Statistical properties of the observed transitions are obtained. The continuum contains the ground-state transitions as well as the branching transitions to the low-lying levels and the subsequent deexcitations of these levels. (orig.)
STEM-EELS analysis of multipole surface plasmon modes in symmetry-broken AuAg nanowire dimers
Schubert, Ina; Sigle, Wilfried; van Aken, Peter A.; Trautmann, Christina; Toimil-Molares, Maria Eugenia
2015-03-01
Surface plasmon coupling in nanowires separated by small gaps generates high field enhancements at the position of the gap and is thus of great interest for sensing applications. It is known that the nanowire dimensions and in particular the symmetry of the structures has strong influence on the plasmonic properties of the dimer structure. Here, we report on multipole surface plasmon coupling in symmetry-broken AuAg nanowire dimers. Our dimers, consisting of two nanowires with different lengths and separated by gaps of only 10 to 30 nm, were synthesized by pulsed electrochemical deposition in ion track-etched polymer templates. Electron energy-loss spectroscopy in scanning transmission electron microscopy allows us to resolve up to nine multipole order surface plasmon modes of these dimers spectrally separated from each other. The spectra evidence plasmon coupling between resonances of different multipole order, resulting in the generation of additional plasmonic modes. Since such complex structures require elaborated synthesis techniques, dimer structures with complex composition, morphology and shape are created. We demonstrate that finite element simulations on pure Au dimers can predict the generated resonances in the fabricated structures. The excellent agreement of our experiment on AuAg dimers with finite integration simulations using CST microwave studio manifests great potential to design complex structures for sensing applications.
an impetus or drive to that account: change, innovation, rupture, or discontinuity. Resonances: Historical Essays on Continuity and Change explores the historiographical question of the modes of interrelation between these motifs in historical narratives. The essays in the collection attempt to realize...... theoretical consciousness through historical narrative ‘in practice’, by discussing selected historical topics from Western cultural history, within the disciplines of history, literature, visual arts, musicology, archaeology, philosophy, and theology. The title Resonances indicates the overall perspective...
A circuit QED controlled-Z ``AMP'' gate (Adiabatic MultiPole gate)
McKay, David C.; Naik, Ravi; Bishop, Lev S.; Schuster, David I.
2014-03-01
Circuit quantum electrodynamics -- superconducting Josephson junction ``transmon'' qubits coupled via microwave cavities -- is a promising route towards scalable quantum computing. Here we report on experiments coupling two transmon qubits through multiple strongly coupled planar superconducting cavities -- the multipole cavity QED architecture. This design enables large interactions (mediated by real cavity photons) when the transmons are resonant with the cavities, and low off rates when the qubits are tuned away from the cavity resonance. In this talk we will discuss our gate protocol -- the AMP gate -- and report on producing a high fidelity Bell state (| gg > + | ee >) measured from state and process tomography. We will discuss future plans for scaling this architecture beyond two qubits.
A new simple multidomain fast multipole boundary element method
Huang, S.; Liu, Y. J.
2016-09-01
A simple multidomain fast multipole boundary element method (BEM) for solving potential problems is presented in this paper, which can be applied to solve a true multidomain problem or a large-scale single domain problem using the domain decomposition technique. In this multidomain BEM, the coefficient matrix is formed simply by assembling the coefficient matrices of each subdomain and the interface conditions between subdomains without eliminating any unknown variables on the interfaces. Compared with other conventional multidomain BEM approaches, this new approach is more efficient with the fast multipole method, regardless how the subdomains are connected. Instead of solving the linear system of equations directly, the entire coefficient matrix is partitioned and decomposed using Schur complement in this new approach. Numerical results show that the new multidomain fast multipole BEM uses fewer iterations in most cases with the iterative equation solver and less CPU time than the traditional fast multipole BEM in solving large-scale BEM models. A large-scale fuel cell model with more than 6 million elements was solved successfully on a cluster within 3 h using the new multidomain fast multipole BEM.
Cardiac magnetic source imaging based on current multipole model
Tang Fa-Kuan; Wang Qian; Hua Ning; Lu Hong; Tang Xue-Zheng; Ma Ping
2011-01-01
It is widely accepted that the heart current source can be reduced into a current multipole. By adopting three linear inverse methods, the cardiac magnetic imaging is achieved in this article based on the current multipole model expanded to the first order terms. This magnetic imaging is realized in a reconstruction plane in the centre of human heart, where the current dipole array is employed to represent realistic cardiac current distribution. The current multipole as testing source generates magnetic fields in the measuring plane, serving as inputs of cardiac magnetic inverse problem. In the heart-torso model constructed by boundary element method, the current multipole magnetic field distribution is compared with that in the homogeneous infinite space, and also with the single current dipole magnetic field distribution.Then the minimum-norm least-squares (MNLS) method, the optimal weighted pseuDOInverse method (OWPIM), and the optimal constrained linear inverse method (OCLIM) are selected as the algorithms for inverse computation based on current multipole model innovatively, and the imaging effects of these three inverse methods are compared. Besides,two reconstructing parameters, residual and mean residual, are also discussed, and their trends under MNLS, OWPIM and OCLIM each as a function of SNR are obtained and compared.
Michels, M.A.J.; Suttorp, L.G.
1972-01-01
The multipole expansion of the retarded interatomic dispersion energy is evaluated in the spherical-tensor formalism. The multipole expansion of the electrostatic dispersion energy follows as a special case.
A parallel fast multipole method for elliptic difference equations
Liska, Sebastian
2014-01-01
A new fast multipole formulation for solving elliptic PDEs on unbounded domains and its parallel implementation are presented. This method formally discretizes the PDE on an infinite Cartesian grid, and then solves the corresponding difference equations. In the analog to solving continuous inhomogeneous differential equations using Green's functions, the proposed method uses the fundamental solution of the discrete operator on an infinite grid, or lattice Green's function. Fast solutions O(N) are achieved by using a kernel-independent interpolation-based fast multipole method. Unlike other fast multipole algorithms, our approach exploits the regularity of the underlying Cartesian grid and the efficiency of FFTs to reduce the computation time. Our parallel implementation allows communications and computations to be overlapped and requires minimal global synchronization. The accuracy, efficiency, and parallel performance of the method are demonstrated through numerical experiments on the discrete 3D Poisson equ...
Advanced multipoles for accelerator magnets theoretical analysis and their measurement
Schnizer, Pierre
2017-01-01
This monograph presents research on the transversal beam dynamics of accelerators and evaluates and describes the respective magnetic field homogeneity. The widely used cylindrical circular multipoles have disadvantages for elliptical apertures or curved trajectories, and the book also introduces new types of advanced multipole magnets, detailing their application, as well as the numerical data and measurements obtained. The research presented here provides more precise descriptions of the field and better estimates of the beam dynamics. Moreover, the effects of field inhomogeneity can be estimated with higher precision than before. These findings are further elaborated to demonstrate their usefulness for real magnets and accelerator set ups, showing their advantages over cylindrical circular multipoles. The research findings are complemented with data obtained from the new superconducting beam guiding magnet models (SIS100) for the FAIR (Facility for Antiproton and Ion Research) project. Lastly, the book...
Guillot, Tristan
2014-01-01
We review the interior structure and evolution of Jupiter, Saturn, Uranus and Neptune, and giant exoplanets with particular emphasis on constraining their global composition. Compared to the first edition of this review, we provide a new discussion of the atmospheric compositions of the solar system giant planets, we discuss the discovery of oscillations of Jupiter and Saturn, the significant improvements in our understanding of the behavior of material at high pressures and the consequences for interior and evolution models. We place the giant planets in our Solar System in context with the trends seen for exoplanets.
Gaussian translation operator for Multi-Level Fast Multipole Method
Borries, Oscar Peter; Hansen, Per Christian; Sorensen, Stig B.
2014-01-01
Results using a new translation operator for the Multi-Level Fast Multipole Method are presented. Based on Gaussian beams, the translation operator allows a significant portion of the plane-wave directions to be neglected, resulting in a much faster translation step.......Results using a new translation operator for the Multi-Level Fast Multipole Method are presented. Based on Gaussian beams, the translation operator allows a significant portion of the plane-wave directions to be neglected, resulting in a much faster translation step....
Analysis of the diamagnetic effect in multipole Galatea traps
Bishaev, A. M.; Bugrova, A. I.; Gavrikov, M. B.; Kozintseva, M. V.; Lipatov, A. S.; Savel'ev, V. V.; Sigov, A. S.; Smirnov, P. G.; Tarelkin, I. A.; Khramtsov, P. P.
2013-04-01
The toroidal current emerging after the injection of a plasmoid through the magnetic shell of the Trimyx-3M (microwave) multipole trap is measured using the Rogowski loop. This current is due to diamagnetism of the plasma. The relation between the diamagnetic current and the maximal plasma pressure produced at the magnetic field separatrix is obtained. It is shown hence that magnetic measurements in a multi-pole trap for a known concentration make it possible to determine the plasma temperature in the trap and the energy confinement time.
Spiralling solitons and multipole localized modes in nonlocal nonlinear media
Buccoliero, Daniel; Lopez-Aguayo, Servando; Skupin, Stefan
2007-01-01
We analyze the propagation of rotating multi-soliton localized structures in optical media with spatially nonlocal nonlinearity. We demonstrate that nonlocality stabilizes the azimuthal breakup of rotating dipole as well as multipole localized soliton modes. We compare the results for two differe...... models of nonlocal nonlinearity and suggest that the stabilization mechanism is a generic property of a spatial nonlocal nonlinear response independent of its particular functional form.......We analyze the propagation of rotating multi-soliton localized structures in optical media with spatially nonlocal nonlinearity. We demonstrate that nonlocality stabilizes the azimuthal breakup of rotating dipole as well as multipole localized soliton modes. We compare the results for two different...
Performance Benchmarking of Fast Multipole Methods
Al-Harthi, Noha A.
2013-06-01
The current trends in computer architecture are shifting towards smaller byte/flop ratios, while available parallelism is increasing at all levels of granularity – vector length, core count, and MPI process. Intel’s Xeon Phi coprocessor, NVIDIA’s Kepler GPU, and IBM’s BlueGene/Q all have a Byte/flop ratio close to 0.2, which makes it very difficult for most algorithms to extract a high percentage of the theoretical peak flop/s from these architectures. Popular algorithms in scientific computing such as FFT are continuously evolving to keep up with this trend in hardware. In the meantime it is also necessary to invest in novel algorithms that are more suitable for computer architectures of the future. The fast multipole method (FMM) was originally developed as a fast algorithm for ap- proximating the N-body interactions that appear in astrophysics, molecular dynamics, and vortex based fluid dynamics simulations. The FMM possesses have a unique combination of being an efficient O(N) algorithm, while having an operational intensity that is higher than a matrix-matrix multiplication. In fact, the FMM can reduce the requirement of Byte/flop to around 0.01, which means that it will remain compute bound until 2020 even if the cur- rent trend in microprocessors continues. Despite these advantages, there have not been any benchmarks of FMM codes on modern architectures such as Xeon Phi, Kepler, and Blue- Gene/Q. This study aims to provide a comprehensive benchmark of a state of the art FMM code “exaFMM” on the latest architectures, in hopes of providing a useful reference for deciding when the FMM will become useful as the computational engine in a given application code. It may also serve as a warning to certain problem size domains areas where the FMM will exhibit insignificant performance improvements. Such issues depend strongly on the asymptotic constants rather than the asymptotics themselves, and therefore are strongly implementation and hardware
Moroz, Alexander
2009-01-01
The contribution of higher-order multipoles to radiative and non-radiative decay of a single dipole emitter close to a spherical metallic nanoparticle is re-examined. Taking a Ag spherical nanoparticle (AgNP) with the radius of 5 nm as an example, a significant contribution (between 50% and 101% of the total value) of higher-order multipoles to non-radiative rates is found even at the emitter distance of 5 nm from the AgNP surface. On the other hand, the higher-order multipole contribution to radiative rates is negligible. Consequently, a dipole-dipole approximation can yield only an upper bound on the apparent quantum yield. In contrast, the non-radiative rates calculated with the quasistatic Gersten and Nitzan method are found to be in much better agreement with exact electrodynamic results. Finally, the size corrected metal dielectric function is shown to decrease the non-radiative rates near the dipolar surface plasmon resonance.
Multilevel Fast Multipole Method for Higher Order Discretizations
Borries, Oscar Peter; Meincke, Peter; Jorgensen, Erik;
2014-01-01
The multi-level fast multipole method (MLFMM) for a higher order (HO) discretization is demonstrated on high-frequency (HF) problems, illustrating for the first time how an efficient MLFMM for HO can be achieved even for very large groups. Applying several novel ideas, beneficial to both lower or...
Two-center-multipole expansion method: application to macromolecular systems
Solov'yov, Ilia; Yakubovich, Alexander V.; Solov'yov, Andrey V.;
2007-01-01
We propose a theoretical method for the calculation of the interaction energy between macromolecular systems at large distances. The method provides a linear scaling of the computing time with the system size and is considered as an alternative to the well-known fast multipole method. Its...
Concept of multipole magnetic ﬁeld rotation in ECRIS
M H Rashid; R K Bhandari
2002-11-01
The conventional type of magnetic well is formed by superposition of two types of magnetic ﬁeld, axial bumpy ﬁeld and radial multipole ﬁeld. It is used to contain plasma that consists of neutrals, ions and electrons. These particles are in constant motion in the well and energetic electrons create plasma by violent collisions with neutrals and ions. The conﬁned electrons are constantly heated by ECR technique in the presence of magnetic ﬁeld. In this paper it has been shown theoretically that how the electron motion is inﬂuenced in terms of heating, containment and azimuthal uniformity of plasma, by the axial rotation of the multipole magnetic ﬁeld [1,2]. Afterwards, the feasibility of achieving a rotating magnetic multipole ﬁeld is discussed to some extent. And it is seen that it is not beyond the capability of the scientiﬁc community in the present scenario of the advanced technology. Presently, it can be achieved for lesser ﬁeld and slightly larger size of the multipole electromagnet and can be used for improvement of the ECR ion source (ECRIS).
Improved Multilevel Fast Multipole Method for Higher-Order discretizations
Borries, Oscar Peter; Meincke, Peter; Jorgensen, Erik
2014-01-01
The Multilevel Fast Multipole Method (MLFMM) allows for a reduced computational complexity when solving electromagnetic scattering problems. Combining this with the reduced number of unknowns provided by Higher-Order discretizations has proven to be a difficult task, with the general conclusion b...
Neutron diffraction study of multipole order in light rare-earth hexaborides
J-M Mignat; J Robert; M Sera; F Iga
2008-10-01
Multipole interactions are known to play a central role in the unconventional properties of light rare-earth hexaborides and especially of CeB6. Substituting Pr at the Ce sites has the effect of enhancing exchange interactions and changing the symmetry of the local 4f charge distribution, while suppressing the octupole moment. The (,) magnetic phase diagrams of the CePr1-B6 compounds display a large variety of ordered phases involving magnetic and/or charge degrees of freedom. Here we focus on the compound Ce0.7Pr0:3B6, which is located slightly beyond the Pr concentration where the antiferroquadrupolar phase of pure CeB6 is suppressed in zero field. The different magnetic structures have been characterized by neutron diffraction and their origin is discussed in connection with recent non-resonant X-ray results by Tanaka et al.
Optical theorem for multipole sources in wave diffraction theory
Eremin, Yu. A.; Sveshnikov, A. G.
2016-05-01
The optical theorem is generalized to the case of local body excitation by multipole sources. It is found that, to calculate the extinction cross section, it is sufficient to calculate the scattered field derivatives at a single point. It is shown that the Purcell factor, which is a rather important parameter, can be represented in analytic form. The result is generalized to the case of a local scatterer incorporated in a homogeneous halfspace.
Extension of the Multipole Approach to Random Metamaterials
A. Chipouline
2012-01-01
Full Text Available Influence of the short-range lateral disorder in the meta-atoms positioning on the effective parameters of the metamaterials is investigated theoretically using the multipole approach. Random variation of the near field quasi-static interaction between metaatoms in form of double wires is shown to be the reason for the effective permittivity and permeability changes. The obtained analytical results are compared with the known experimental ones.
Prediction of conformationally dependent atomic multipole moments in carbohydrates.
Cardamone, Salvatore; Popelier, Paul L A
2015-12-15
The conformational flexibility of carbohydrates is challenging within the field of computational chemistry. This flexibility causes the electron density to change, which leads to fluctuating atomic multipole moments. Quantum Chemical Topology (QCT) allows for the partitioning of an "atom in a molecule," thus localizing electron density to finite atomic domains, which permits the unambiguous evaluation of atomic multipole moments. By selecting an ensemble of physically realistic conformers of a chemical system, one evaluates the various multipole moments at defined points in configuration space. The subsequent implementation of the machine learning method kriging delivers the evaluation of an analytical function, which smoothly interpolates between these points. This allows for the prediction of atomic multipole moments at new points in conformational space, not trained for but within prediction range. In this work, we demonstrate that the carbohydrates erythrose and threose are amenable to the above methodology. We investigate how kriging models respond when the training ensemble incorporating multiple energy minima and their environment in conformational space. Additionally, we evaluate the gains in predictive capacity of our models as the size of the training ensemble increases. We believe this approach to be entirely novel within the field of carbohydrates. For a modest training set size of 600, more than 90% of the external test configurations have an error in the total (predicted) electrostatic energy (relative to ab initio) of maximum 1 kJ mol(-1) for open chains and just over 90% an error of maximum 4 kJ mol(-1) for rings. © 2015 Wiley Periodicals, Inc.
PROGRAM-PATTERN MULTIPOLE BOUNDARY ELEMENT METHOD FOR FRICTIONAL CONTACT
Yu Chunxiao; Shen Guangxian; Liu Deyi
2005-01-01
A mathematical program is proposed for the highly nonlinear problem involving frictional contact. A program-pattern using the fast multipole boundary element method (FMBEM) is given for 3-D elastic contact with friction to replace the Monte Carlo method. A new optimized generalized minimal residual (GMRES) algorithm is presented. Numerical examples demonstrate the validity of the program-pattern optimization model for node-to-surface contact with friction. The GMRES algorithm greatly improves the computational efficiency.
Mathematical Programming Solution for the Frictional Contact Multipole BEM
YU Chunxiao; SHEN Guangxian; LIU Deyi
2005-01-01
This paper presents a new mathematical model for the highly nonlinear problem of frictional contact. A programming model, multipole boundary element method (BEM), was developed for 3-D elastic contact with friction to replace the Monte Carlo method. A numerical example shows that the optimization programming model for the point-to-surface contact with friction and the fast optimization generalized minimal residual algorithm (GMRES(m)) significantly improve the analysis of such problems relative to the conventional BEM.
A single-site multipole model for liquid water
Tran, Kelly N.; Tan, Ming-Liang; Ichiye, Toshiko
2016-07-01
Accurate and efficient empirical potential energy models that describe the atomistic interactions between water molecules in the liquid phase are essential for computer simulations of many problems in physics, chemistry, and biology, especially when long length or time scales are important. However, while models with non-polarizable partial charges at four or five sites in a water molecule give remarkably good values for certain properties, deficiencies have been noted in other properties and increasing the number of sites decreases computational efficiency. An alternate approach is to utilize a multipole expansion of the electrostatic potential due to the molecular charge distribution, which is exact outside the charge distribution in the limits of infinite distances or infinite orders of multipoles while partial charges are a qualitative representation of electron density as point charges. Here, a single-site multipole model of water is presented, which is as fast computationally as three-site models but is also more accurate than four- and five-site models. The dipole, quadrupole, and octupole moments are from quantum mechanical-molecular mechanical calculations so that they account for the average polarization in the liquid phase, and represent both the in-plane and out-of-plane electrostatic potentials of a water molecule in the liquid phase. This model gives accurate thermodynamic, dynamic, and dielectric properties at 298 K and 1 atm, as well as good temperature and pressure dependence of these properties.
Development of a multi-pole magnetorheological brake
Shiao, Yaojung; Nguyen, Quang-Anh
2013-06-01
This paper presents a new approach in the design and optimization of a novel multi-pole magnetorheological (MR) brake that employs magnetic flux more effectively on the surface of the rotor. MR brakes with conventional single ring-type electromagnetic poles have reached the limits of torque enhancement. One major reason is the limitation of the magnetic field strength within the active area of the MR fluid due to the geometric constraints of the coil. The multi-pole MR brake design features multiple electromagnetic poles surrounded by several coils. As a result, the active chaining areas for the MR fluid are greatly increased, and significant brake torque improvement is achieved. The coil structure, as a part of the stator, becomes flexible and customizable in terms of space usage for the winding and bobbin design. In addition, this brake offers extra options in its dimensions for torque enhancement because either the radial or the axial dimensions of the rotor can be increased. Magnetic circuit analysis was conducted to analyze the effects of the design parameters on the field torque. After that, simulations were done to find the optimal design under all major geometric constraints with a given power supply. The results show that the multi-pole MR brake provides a considerable braking torque increase while maintaining a compact and solid design. This is confirmation of its feasibility in actual braking applications.
Cluster-Based Multipolling Sequencing Algorithm for Collecting RFID Data in Wireless LANs
Choi, Woo-Yong; Chatterjee, Mainak
2015-03-01
With the growing use of RFID (Radio Frequency Identification), it is becoming important to devise ways to read RFID tags in real time. Access points (APs) of IEEE 802.11-based wireless Local Area Networks (LANs) are being integrated with RFID networks that can efficiently collect real-time RFID data. Several schemes, such as multipolling methods based on the dynamic search algorithm and random sequencing, have been proposed. However, as the number of RFID readers associated with an AP increases, it becomes difficult for the dynamic search algorithm to derive the multipolling sequence in real time. Though multipolling methods can eliminate the polling overhead, we still need to enhance the performance of the multipolling methods based on random sequencing. To that extent, we propose a real-time cluster-based multipolling sequencing algorithm that drastically eliminates more than 90% of the polling overhead, particularly so when the dynamic search algorithm fails to derive the multipolling sequence in real time.
Multipole interference in the second-harmonic optical radiation from gold nanoparticles.
Kujala, Sami; Canfield, Brian K; Kauranen, Martti; Svirko, Yuri; Turunen, Jari
2007-04-20
We provide experimental evidence of higher multipole (magnetic dipole and electric quadrupole) radiation in second-harmonic (SH) generation from arrays of metal nanoparticles. Fundamental differences in the radiative properties of electric dipoles and higher multipoles yield opposite interference effects observed in the SH intensities measured in the reflected and transmitted directions. These interference effects clearly depend on the polarization of the fundamental field, directly indicating the importance of multipole effects in the nonlinear response. We estimate that higher multipoles contribute up to 20% of the total emitted SH field amplitude for certain polarization configurations.
Investigation of Multipole Electrostatics in Hydration Free Energy Calculations
Shi, Yue; Wu, Chuanjie; Ponder, Jay W.; Ren, Pengyu
2010-01-01
Hydration free energy (HFE) is generally used for evaluating molecular solubility, which is an important property for pharmaceutical and chemical engineering processes. Accurately predicting HFE is also recognized as one fundamental capability of molecular mechanics force field. Here we present a systematic investigation on HFE calculations with AMOEBA polarizable force field at various parameterization and simulation conditions. The HFEs of seven small organic molecules have been obtained alchemically using the Bennett Acceptance Ratio (BAR) method. We have compared two approaches to derive the atomic multipoles from quantum mechanical (QM) calculations: one directly from the new distributed multipole analysis (DMA) and the other involving fitting to the electrostatic potential around the molecules. Wave functions solved at the MP2 level with four basis sets (6-311G*, 6-311++G(2d,2p), cc-pVTZ, and aug-cc-pVTZ) are used to derive the atomic multipoles. HFEs from all four basis sets show a reasonable agreement with experimental data (root mean square error 0.63 kcal/mol for aug-ccpVTZ). We conclude that aug-cc-pVTZ gives the best performance when used with AMOEBA, and 6-311++G(2d,2p) is comparable but more efficient for larger systems. The results suggest that the inclusion of diffuse basis functions is important for capturing intermolecular interactions. The effect of long-range correction to van der Waals interaction on the hydration free energies is about 0.1 kcal/mol when the cutoff is 12Å, and increases linearly with the number of atoms in the solute/ligand. In addition, we also discussed the results from a hybrid approach that combines polarizable solute with fixed-charge water in the hydration free energy calculation. PMID:20925089
Multipole expansions in the representation of current sources.
Trontelj, Z; Jazbinsek, V; Erné, S N; Trahms, L
1991-01-01
After obtaining the measured magnetic field or its components in the form of an isofield map one has to decide which approximation to use in solving the inverse problem. A single current dipole as an equivalent current source is often used. It will be shown when this approximation fails and one possible way to improve the equivalent source description. The expansion of current multipoles is discussed up to the second order. The localization of an equivalent current source in this case is considered. The application of this type of expansion is analysed and discussed.
Experimental demonstration of a surface-electrode multipole ion trap
Maurice, Mark; Green, Dylan; Farr, Andrew; Burke, Timothy; Hilleke, Russell; Clark, Robert
2015-01-01
We report on the design and experimental characterization of a surface-electrode multipole ion trap. Individual microscopic sugar particles are confined in the trap. The trajectories of driven particle motion are compared with a theoretical model, both to verify qualitative predictions of the model, and to measure the charge-to-mass ratio of the confined particle. The generation of harmonics of the driving frequency is observed as a key signature of the nonlinear nature of the trap. We remark on possible applications of our traps, including to mass spectrometry.
Analytical expressions for fringe fields in multipole magnets
B. D. Muratori
2015-06-01
Full Text Available Fringe fields in multipole magnets can have a variety of effects on the linear and nonlinear dynamics of particles moving along an accelerator beam line. An accurate model of an accelerator must include realistic models of the magnet fringe fields. Fringe fields for dipoles are well understood and can be modeled at an early stage of accelerator design in such codes as mad8, madx, gpt or elegant. Existing techniques for quadrupole and higher order multipoles rely either on the use of a numerical field map, or on a description of the field in the form of a series expansion about a chosen axis. Usually, it is not until the later stages of a design project that such descriptions (based on magnet modeling or measurement become available. Furthermore, series expansions rely on the assumption that the beam travels more or less on axis throughout the beam line; but in some types of machines (for example, Fixed Field Alternating Gradients or FFAGs this is not a good assumption. Furthermore, some tracking codes, such as gpt, use methods for including space charge effects that require fields to vary smoothly and continuously along a beam line: in such cases, realistic fringe field models are of significant importance. In this paper, a method for constructing analytical expressions for multipole fringe fields is presented. Such expressions allow fringe field effects to be included in beam dynamics simulations from the start of an accelerator design project, even before detailed magnet design work has been undertaken. The magnetostatic Maxwell equations are solved analytically and a solution that fits all orders of multipoles is derived. Quadrupole fringe fields are considered in detail as these are the ones that give the strongest effects. The analytic expressions for quadrupole fringe fields are compared with data obtained from numerical modeling codes in two cases: a magnet in the high luminosity upgrade of the Large Hadron Collider inner triplet, and a
Deriving static atomic multipoles from the electrostatic potential.
Kramer, Christian; Bereau, Tristan; Spinn, Alexander; Liedl, Klaus R; Gedeck, Peter; Meuwly, Markus
2013-12-23
The description of molecular systems using multipolar electrostatics calls for automated methods to fit the necessary parameters. In this paper, we describe an open-source software package that allows fitting atomic multipoles (MTPs) from the ab initio electrostatic potential by adequate atom typing and judicious assignment of the local axis system. By enabling the simultaneous fit of several molecules and/or conformations, the package addresses issues of parameter transferability and lack of sampling for buried atoms. We illustrate the method by studying a series of small alcohol molecules, as well as various conformations of protonated butylamine.
New Multipole Method for 3-D Capacitance Extraction
Zhao-Zhi Yang; Ze-Yi Wang
2004-01-01
This paper describes an effcient improvement of the multipole accelerated boundary element method for 3-D capacitance extraction.The overall relations between the positions of 2-D boundary elements are considered instead of only the relations between the center-points of the elements,and a new method of cube partitioning is introduced.Numerical results are presented to demonstrate that the method is accurate and has nearly linear computational growth as O(n),where n is the number of panels/boundary elements.The proposed method is more accurate and much faster than Fastcap.
Magnetostatic solution by hybrid technique and fast multipole method
Gruosso, G. [Politecnico di Milano, Dipartimento di Elettronica e Informazione, I-20133 Milan (Italy); Repetto, M. [Politecnico di Torino, Dipartimento di Ingegneria Elettrica, C.so Duca Abruzzi 24, I-10129 Turin (Italy)], E-mail: maurizio.repetto@polito.it
2008-02-01
The use of fast multipole method (FMM) in the solution of a magnetostatic problem is presented. The magnetostatic solution strategy is based on finite formulation of electromagnetic field coupled with an integral formulation for the definition of boundary conditions on the external surface of the unstructured mesh. Due to the hypothesis of micromagnetic problem, the resulting matrix structure is sparse and integral terms are only on the RHS. Magnetic surface charge is used as source of these integral terms and is localized on the faces between tetrahedra. The computation of the integral terms can be performed by analytical formulas for the near field contributes and by FMM for far field ones.
Multipole Expansions of Aggregate Charge: How Far to Go?
Matthews, Lorin S; Hyde, Truell W
2015-01-01
Aggregates immersed in a plasma or radiative environment will have charge distributed over their extended surface. Previous studies have modeled the aggregate charge using the monopole and dipole terms of a multipole expansion, with results indicating that the dipole-dipole interactions play an important role in increasing the aggregation rate and altering the morphology of the resultant aggregates. This study examines the effect that including the quadrupole terms has on the dynamics of aggregates interacting with each other and the confining electric fields in laboratory experiments. Results are compared to modeling aggregates as a collection of point charges located at the center of each spherical monomer comprising the aggregate.
Higher Electric Multipole Moments for Some Polyatomic Molecules from Accurate SCF Calculations
Telhat Ozdogan
2002-01-01
Higher electric multipole moments for the ground-state electronic configuration of some polyatomicmolecules, i.e. CH4, NH3, H2O, were calculated from SCF-HFR wavefunctions using Slater-type orbital basis sets.The calculated results for electric multipole moments of these molecules are in good agreement with the theoretical andexperimental ones.
The gravitational time delay in the field of a slowly moving body with arbitrary multipoles
Soffel, Michael H., E-mail: michael.soffel@tu-dresden.de [Shanghai Astronomical Observatory, 80 Nandan Road, Shanghai, 200030 (China); Lohmann Observatory, Helmholtzstrasse 10, D-01062 Dresden (Germany); Han, Wen-Biao, E-mail: wbhan@shao.ac.cn [Shanghai Astronomical Observatory, 80 Nandan Road, Shanghai, 200030 (China)
2015-02-06
We calculate the time delay of light in the gravitational field of a slowly moving body with arbitrary multipoles (mass and spin multipole moments) by the Time-Transfer-Function (TTF) formalism. The parameters we use, first introduced by Kopeikin for a gravitational source at rest, make the integration of the TTF very elegant and simple. Results completely coincide with expressions from the literature. The results for a moving body (with constant velocity) with complete multipole-structure are new, according to our knowledge. - Highlights: • The Time-Transfer-Function (TTF) is used to calculate the gravitational time delay. • The time delay for a body with arbitrary multipoles at rest is calculated in a very simply manner. • The gravitational time delay induced by a slowly moving body with arbitrary multipoles is derived for the first time.
Optimal design of a new multipole bilayer magnetorheological brake
Shiao, Yaojung; Ngoc, Nguyen Anh; Lai, Chien-Hung
2016-11-01
This article presents a new high-torque multipole bilayer magneto-rheological brake (MRB). This MRB has a unique structural design with multiple electromagnetic poles and multiple media layers of magnetorheological fluid (MRF). The MRB has two rotors located on the outer and inner sides of a six-pole stator, and therefore, it can provide higher torque and a larger torque-to-volume ratio (TVR) than conventional single- or multipole single-layer MRBs can. Moreover, the problem of potential MRF leakage is solved by using cylindrical separator rings around the stator. In this study, first, the structure of the proposed MRB is introduced. An analog magnetic circuit was built for the MRB to investigate the effects of the MRB parameters on the magnetic field intensity of the MRF layers. In addition, a 3D electromagnetic model of the MRB was developed to simulate and examine the magnetic flux intensity and corresponding braking torque. An approximate optimization method was then applied to obtain the optimal geometric dimensions for the major dimensional parameters of the MRB. The MRB was manufactured and tested to validate its torque and dynamic characteristics. The results showed that the proposed MRB exhibited great enhancement of the braking torque and TVR.
Alleviating the tension at low multipole through Axion Monodromy
Meerburg, P Daniel
2014-01-01
There exists some tension on large scales between the Planck data and the LCDM concordance model of the Universe, which has been amplified by the recently claimed discovery of non-zero tensor to scalar ratio $r$. At the same time, the current best-fit value of $r$ suggests large field inflation delta phi>M_p, which requires a UV complete description of inflation. A very promising working example that predicts large tensor modes and can be UV completed is axion monodromy inflation. This realization of inflation naturally produces oscillating features, as consequence of a broken shift symmetry. We analyse a combination of Planck, ACT, SPT, WMAP low l polarization and BICEP2 data, and show a long wavelength feature from a periodic potential can alleviate the tension at low multipoles with an improvement delta chi^2 ~2.5-4 per degree of freedom, depending on the level of foreground subtraction. As with an introduction of running, one expects that any scale dependence should lead to a worsened fit at high multipol...
Scalable force directed graph layout algorithms using fast multipole methods
Yunis, Enas Abdulrahman
2012-06-01
We present an extension to ExaFMM, a Fast Multipole Method library, as a generalized approach for fast and scalable execution of the Force-Directed Graph Layout algorithm. The Force-Directed Graph Layout algorithm is a physics-based approach to graph layout that treats the vertices V as repelling charged particles with the edges E connecting them acting as springs. Traditionally, the amount of work required in applying the Force-Directed Graph Layout algorithm is O(|V|2 + |E|) using direct calculations and O(|V| log |V| + |E|) using truncation, filtering, and/or multi-level techniques. Correct application of the Fast Multipole Method allows us to maintain a lower complexity of O(|V| + |E|) while regaining most of the precision lost in other techniques. Solving layout problems for truly large graphs with millions of vertices still requires a scalable algorithm and implementation. We have been able to leverage the scalability and architectural adaptability of the ExaFMM library to create a Force-Directed Graph Layout implementation that runs efficiently on distributed multicore and multi-GPU architectures. © 2012 IEEE.
A Multipole Expansion Method for Analyzing Lightning Field Changes
Koshak, William J.; Krider, E. Philip; Murphy, Martin J.
1999-01-01
Changes in the surface electric field are frequently used to infer the locations and magnitudes of lightning-caused changes in thundercloud charge distributions. The traditional procedure is to assume that the charges that are effectively deposited by the flash can be modeled either as a single point charge (the Q model) or a point dipole (the P model). The Q model has four unknown parameters and provides a good description of many cloud-to-ground (CG) flashes. The P model has six unknown parameters and describes many intracloud (IC) discharges. In this paper we introduce a new analysis method that assumes that the change in the cloud charge can be described by a truncated multipole expansion, i.e., there are both monopole and dipole terms in the unknown source distribution, and both terms are applied simultaneously. This method can be used to analyze CG flashes that are accompanied by large changes in the cloud dipole moment and complex IC discharges. If there is enough information content in the measurements, the model can also be generalized to include quadrupole and higher order terms. The parameters of the charge moments are determined using a dme-dimensional grid search in combination with a linear inversion, and because of this, local minima in the error function and the associated solution ambiguities are avoided. The multipole method has been tested on computer-simulated sources and on natural lightning at the NASA Kennedy Space Center and U.S. Air Force Eastern Range.
Giant arachnoid granulation in a patient with benign intracranial hypertension
Kiroglu, Yilmaz; Yaqci, Baki; Cirak, Bayram; Karabulut, Nevzat [Pamukkale University, Department of Radiology, School of Medicine, Denizli (Turkey)
2008-10-15
We report magnetic resonance (MR), computed tomography (CT) and angiographic imaging of an unusual giant arachnoid granulation in the superior sagittal sinus in a man with headache and vertigo. Intrasinus pressure measurements revealed a significant pressure gradient across the lesion. MR imaging is useful to identify giant arachnoid granulation and dural sinus thrombosis, whereas dural sinus pressure measurement in certain cases of giant arachnoid granulations can be used to evaluate the lesion as the cause of the patient's symptoms. (orig.)
Piekarewicz, J
2012-01-01
Understanding the equation of state (EOS) of neutron-rich matter is a central goal of nuclear physics that cuts across a variety of disciplines. Indeed, the limits of nuclear existence, the collision of energetic heavy ions, the structure of neutron stars, and the dynamics of core-collapse supernova all depend critically on the nuclear-matter EOS. In this contribution I focus on the EOS of cold baryonic matter with special emphasis on its impact on the structure, dynamics, and composition of neutron stars. In particular, I discuss how laboratory experiments on neutron skins as well as on Pygmy and Giant resonances can help us elucidate the structure of these fascinating objects.
Jakobsen, Sofie; Jensen, Frank
2014-12-09
We assess the accuracy of force field (FF) electrostatics at several levels of approximation from the standard model using fixed partial charges to conformational specific multipole fits including up to quadrupole moments. Potential-derived point charges and multipoles are calculated using least-squares methods for a total of ∼1000 different conformations of the 20 natural amino acids. Opposed to standard charge fitting schemes the procedure presented in the current work employs fitting points placed on a single isodensity surface, since the electrostatic potential (ESP) on such a surface determines the ESP at all points outside this surface. We find that the effect of multipoles beyond partial atomic charges is of the same magnitude as the effect due to neglecting conformational dependency (i.e., polarizability), suggesting that the two effects should be included at the same level in FF development. The redundancy at both the partial charge and multipole levels of approximation is quantified. We present an algorithm which stepwise reduces or increases the dimensionality of the charge or multipole parameter space and provides an upper limit of the ESP error that can be obtained at a given truncation level. Thereby, we can identify a reduced set of multipole moments corresponding to ∼40% of the total number of multipoles. This subset of parameters provides a significant improvement in the representation of the ESP compared to the simple point charge model and close to the accuracy obtained using the complete multipole parameter space. The selection of the ∼40% most important multipole sites is highly transferable among different conformations, and we find that quadrupoles are of high importance for atoms involved in π-bonding, since the anisotropic electric field generated in such regions requires a large degree of flexibility.
Multipole-preserving quadratures for discretization of functions
Genovese, Luigi
2015-01-01
Discretizing an analytic function on a uniform real-space grid is often done via a straightforward collocation method. This is ubiquitous in all areas of computational physics and quantum chemistry. An example in Density Functional Theory is given by the local external potential describing the interaction between ions and electrons. Also notable examples are given by the analytic functions defining compensation charges for range-separated electrostatic treatments. The accuracy of the collocation method used is therefore very important for the reliability of subsequent treatments like self-consistent field solutions of the electronic structure problems. When the real-space grid is too coarse, the collocation method introduces numerical artifacts typical of real-space treatments, like the so-called egg-box error, that may spoil the numerical stability of the description. We present in this paper a new quadrature scheme that is able to exactly preserve the multipoles of a given analytic function for a wide range...
Fast Multipole-Based Preconditioner for Sparse Iterative Solvers
Ibeid, Huda
2014-05-04
Among optimal hierarchical algorithms for the computational solution of elliptic problems, the Fast Multipole Method (FMM) stands out for its adaptability to emerging architectures, having high arithmetic intensity, tunable accuracy, and relaxed global synchronization requirements. We demonstrate that, beyond its traditional use as a solver in problems for which explicit free-space kernel representations are available, the FMM has applicability as a preconditioner in finite domain elliptic boundary value problems, by equipping it with boundary integral capability for finite boundaries and by wrapping it in a Krylov method for extensibility to more general operators. Compared with multilevel methods, it is capable of comparable algebraic convergence rates down to the truncation error of the discretized PDE, and it has superior multicore and distributed memory scalability properties on commodity architecture supercomputers.
Point sources and multipoles in inverse scattering theory
Potthast, Roland
2001-01-01
Over the last twenty years, the growing availability of computing power has had an enormous impact on the classical fields of direct and inverse scattering. The study of inverse scattering, in particular, has developed rapidly with the ability to perform computational simulations of scattering processes and led to remarkable advances in a range of applications, from medical imaging and radar to remote sensing and seismic exploration. Point Sources and Multipoles in Inverse Scattering Theory provides a survey of recent developments in inverse acoustic and electromagnetic scattering theory. Focusing on methods developed over the last six years by Colton, Kirsch, and the author, this treatment uses point sources combined with several far-reaching techniques to obtain qualitative reconstruction methods. The author addresses questions of uniqueness, stability, and reconstructions for both two-and three-dimensional problems.With interest in extracting information about an object through scattered waves at an all-ti...
Real space electrostatics for multipoles. III. Dielectric Properties
Lamichhane, Madan; Newman, Kathie E; Gezelter, J Daniel
2016-01-01
In the first two papers in this series, we developed new shifted potential (SP), gradient shifted force (GSF), and Taylor shifted force (TSF) real-space methods for multipole interactions in condensed phase simulations. Here, we discuss the dielectric properties of fluids that emerge from simulations using these methods. Most electrostatic methods (including the Ewald sum) require correction to the conducting boundary fluctuation formula for the static dielectric constants, and we discuss the derivation of these corrections for the new real space methods. For quadrupolar fluids, the analogous material property is the quadrupolar susceptibility. As in the dipolar case, the fluctuation formula for the quadrupolar susceptibility has corrections that depend on the electrostatic method being utilized. One of the most important effects measured by both the static dielectric and quadrupolar susceptibility is the ability to screen charges embedded in the fluid. We use potentials of mean force between solvated ions to...
Elliptical multipole wiggler beamlines at the advanced photon source
Beno, M.A. E-mail: beno@anl.gov; Kurtz, C.; Munkholm, A.; Ruett, U.; Engbretson, M.; Jennings, G.; Linton, J.; Knapp, G.S.; Montano, P.A
2001-07-21
The Basic Energy Sciences Synchrotron Radiation Center Collaborative Access Team has built three independent beamlines, which simultaneously utilize the X-ray radiation from an elliptical multipole wiggler, located at Sector 11 of the Advanced Photon Source. This insertion device produces circularly polarized X-rays on-axis and linearly polarized X-rays above and below the ring plane. The lower linearly polarized radiation is used in the monochromatic 11ID-D station for scattering and spectroscopy experiments in the 5-40 keV range. The on-axis circularly polarized photons are used for magnetic Compton scattering experiments in the 11ID-B station. The upper linearly polarized radiation is utilized by the high-energy diffraction station, 11ID-C. We report here on the beamline optics and experimental station equipment.
Pipelining the Fast Multipole Method over a Runtime System
Agullo, Emmanuel; Coulaud, Olivier; Darve, Eric; Messner, Matthias; Toru, Takahashi
2012-01-01
Fast Multipole Methods (FMM) are a fundamental operation for the simulation of many physical problems. The high performance design of such methods usually requires to carefully tune the algorithm for both the targeted physics and the hardware. In this paper, we propose a new approach that achieves high performance across architectures. Our method consists of expressing the FMM algorithm as a task flow and employing a state-of-the-art runtime system, StarPU, in order to process the tasks on the different processing units. We carefully design the task flow, the mathematical operators, their Central Processing Unit (CPU) and Graphics Processing Unit (GPU) implementations, as well as scheduling schemes. We compute potentials and forces of 200 million particles in 48.7 seconds on a homogeneous 160 cores SGI Altix UV 100 and of 38 million particles in 13.34 seconds on a heterogeneous 12 cores Intel Nehalem processor enhanced with 3 Nvidia M2090 Fermi GPUs.
An adaptive fast multipole accelerated Poisson solver for complex geometries
Askham, T.; Cerfon, A. J.
2017-09-01
We present a fast, direct and adaptive Poisson solver for complex two-dimensional geometries based on potential theory and fast multipole acceleration. More precisely, the solver relies on the standard decomposition of the solution as the sum of a volume integral to account for the source distribution and a layer potential to enforce the desired boundary condition. The volume integral is computed by applying the FMM on a square box that encloses the domain of interest. For the sake of efficiency and convergence acceleration, we first extend the source distribution (the right-hand side in the Poisson equation) to the enclosing box as a C0 function using a fast, boundary integral-based method. We demonstrate on multiply connected domains with irregular boundaries that this continuous extension leads to high accuracy without excessive adaptive refinement near the boundary and, as a result, to an extremely efficient ;black box; fast solver.
Fourier-Based Fast Multipole Method for the Helmholtz Equation
Cecka, Cris
2013-01-01
The fast multipole method (FMM) has had great success in reducing the computational complexity of solving the boundary integral form of the Helmholtz equation. We present a formulation of the Helmholtz FMM that uses Fourier basis functions rather than spherical harmonics. By modifying the transfer function in the precomputation stage of the FMM, time-critical stages of the algorithm are accelerated by causing the interpolation operators to become straightforward applications of fast Fourier transforms, retaining the diagonality of the transfer function, and providing a simplified error analysis. Using Fourier analysis, constructive algorithms are derived to a priori determine an integration quadrature for a given error tolerance. Sharp error bounds are derived and verified numerically. Various optimizations are considered to reduce the number of quadrature points and reduce the cost of computing the transfer function. © 2013 Society for Industrial and Applied Mathematics.
Polarizable Atomic Multipole Solutes in a Poisson-Boltzmann Continuum
Schnieders, Michael J.; Baker, Nathan A.; Ren, Pengyu; Ponder, Jay W.
2008-01-01
Modeling the change in the electrostatics of organic molecules upon moving from vacuum into solvent, due to polarization, has long been an interesting problem. In vacuum, experimental values for the dipole moments and polarizabilities of small, rigid molecules are known to high accuracy; however, it has generally been difficult to determine these quantities for a polar molecule in water. A theoretical approach introduced by Onsager used vacuum properties of small molecules, including polarizability, dipole moment and size, to predict experimentally known permittivities of neat liquids via the Poisson equation. Since this important advance in understanding the condensed phase, a large number of computational methods have been developed to study solutes embedded in a continuum via numerical solutions to the Poisson-Boltzmann equation (PBE). Only recently have the classical force fields used for studying biomolecules begun to include explicit polarization in their functional forms. Here we describe the theory underlying a newly developed Polarizable Multipole Poisson-Boltzmann (PMPB) continuum electrostatics model, which builds on the Atomic Multipole Optimized Energetics for Biomolecular Applications (AMOEBA) force field. As an application of the PMPB methodology, results are presented for several small folded proteins studied by molecular dynamics in explicit water as well as embedded in the PMPB continuum. The dipole moment of each protein increased on average by a factor of 1.27 in explicit water and 1.26 in continuum solvent. The essentially identical electrostatic response in both models suggests that PMPB electrostatics offers an efficient alternative to sampling explicit solvent molecules for a variety of interesting applications, including binding energies, conformational analysis, and pKa prediction. Introduction of 150 mM salt lowered the electrostatic solvation energy between 2–13 kcal/mole, depending on the formal charge of the protein, but had only a
The Formation of Multipoles during the High-Temperature Creep of Austenitic Stainless Steels
Howell, J.; Nielsson, O.; Horsewell, Andy
1981-01-01
It is shown that multipole dislocation configurations can arise during power-law creep of certain austenitic stainless steels. These multipoles have been analysed in some detail for two particular steels (Alloy 800 and a modified AISI 316L) and it is suggested that they arise either during...... instantaneous loading or during the primary creep stage. Trace analysis has shown that the multipoles are confined to {1 1 1} planes during primary creep but are not necessarily confined to these planes during steady-state creep unless they are pinned by interstitials....
Analytical study of the conjecture rule for the combination of multipole effects in LHC
Guignard, Gilbert
1997-01-01
This paper summarizes the analytical investigation done on the conjecture law found by tracking for the effect on the dynamic aperture of the combination of two multipoles of various order. A one-dimensional model leading to an integrable system has been used to find closed formulae for the dynamic aperture associated with a fully distributed multipole. The combination has then been studied and the resulting expression compared with the assumed conjecture law. For integrated multipoles small with respect to the focusing strength, the conjecture appears to hold, though with an exponent different from the one expected by crude reasoning.
The gravitational time delay in the field of a slowly moving body with arbitrary multipoles
Soffel, Michael H
2014-01-01
We calculate the time delay of light in the gravitational field of a slowly moving body with arbitrary multipoles (mass and spin multipole moments) by the time-transfer-function (TTF) formalism. The parameters we use, first introduced by Kopeikin for a gravitational source at rest, make the integration of the TTF very elegant and simple. Results completely coincide with expressions from the literature. The results for a moving body (with constant velocity) with complete multipole-structure are new, according to our knowledge.
Chung, Ting-Yi; Huang, Szu-Jung; Fu, Huang-Wen; Chang, Ho-Ping; Chang, Cheng-Hsiang [National Synchrotron Radiation Research Center, Hsinchu Science Park, Hsinchu 30076, Taiwan (China); Hwang, Ching-Shiang [National Synchrotron Radiation Research Center, Hsinchu Science Park, Hsinchu 30076, Taiwan (China); Department of Electrophysics, National Chiao Tung University, Hsinchu 30050, Taiwan (China)
2016-08-01
The effect of an APPLE II-type elliptically polarized undulator (EPU) on the beam dynamics were investigated using active and passive methods. To reduce the tune shift and improve the injection efficiency, dynamic multipole errors were compensated using L-shaped iron shims, which resulted in stable top-up operation for a minimum gap. The skew quadrupole error was compensated using a multipole corrector, which was located downstream of the EPU for minimizing betatron coupling, and it ensured the enhancement of the synchrotron radiation brightness. The investigation methods, a numerical simulation algorithm, a multipole error correction method, and the beam-based measurement results are discussed.
Sign-Reversal Coupling in Coupled-Resonator Optical Waveguide
Gao, Zhen; Zhang, Youming; Zhang, Baile
2016-01-01
Coupled-resonator optical waveguides (CROWs), which play a significant role in modern photonics, achieve waveguiding through near-field coupling between tightly localized resonators. The coupling factor, a critical parameter in CROW theory, determines the coupling strength between two resonators and the waveguiding dispersion of a CROW. However, the original CROW theory proposed by Yariv et al. only demonstrated one value of coupling factor for a multipole resonance mode. Here, by imaging the tight-binding Bloch waves on a CROW consisting of designer-surface-plasmon resonators in the microwave regime, we demonstrate that the coupling factor in the CROW theory can reverse its sign for a multipole resonance mode. This determines two different waveguiding dispersion curves in the same frequency range, experimentally confirmed by matching Bloch wavevectors and frequencies in the CROW. Our study supplements and extends the original CROW theory, and may find novel use in functional photonic systems.
Kanter, Rosabeth Moss
2008-01-01
Large corporations have long been seen as lumbering, inflexible, bureaucratic--and clueless about global developments. But recently some multinationals seem to be transforming themselves: They're engaging employees, moving quickly, and introducing innovations that show true connection with the world. Harvard Business School's Kanter ventured with a research team inside a dozen global giants--including IBM, Procter & Gamble, Omron, CEMEX, Cisco, and Banco Real--to discover what has been driving the change. After conducting more than 350 interviews on five continents, she and her colleagues came away with a strong sense that we are witnessing the dawn of a new model of corporate power: The coordination of actions and decisions on the front lines now appears to stem from widely shared values and a sturdy platform of common processes and technology, not from top-down decrees. In particular, the values that engage the passions of far-flung workforces stress openness, inclusion, and making the world a better place. Through this shift in what might be called their guidance systems, the companies have become as creative and nimble as much smaller ones, even while taking on social and environmental challenges of a scale that only large enterprises could attempt. IBM, for instance, has created a nonprofit partnership, World Community Grid, through which any organization or individual can donate unused computing power to research projects and see what is being done with the donation in real time. IBM has gained an inspiring showcase for its new technology, helped business partners connect with the company in a positive way, and offered individuals all over the globe the chance to contribute to something big.
Giant cell arteritis is a disorder that causes inflammation of your arteries, usually in the scalp, neck, and arms. ... arteries, which keeps blood from flowing well. Giant cell arteritis often occurs with another disorder called polymyalgia ...
Murugesu, Muralee; Takahashi, Susumu; Wilson, Anthony; Abboud, Khalil A; Wernsdorfer, Wolfgang; Hill, Stephen; Christou, George
2008-10-20
The synthesis and structural, spectroscopic, and magnetic characterization of a Mn25 coordination cluster with a large ground-state spin of S = 51/2 are reported. Reaction of MnCl2 with pyridine-2,6-dimethanol (pdmH2) and NaN3 in MeCN/MeOH gives the mixed valence cluster [Mn25O18(OH)2(N3)12(pdm)6(pdmH)6]Cl2 (1; 6Mn(II), 18Mn(III), Mn(IV)), which has a barrel-like cage structure. Variable temperature direct current (dc) magnetic susceptibility data were collected in the 1.8-300 K temperature range in a 0.1 T field. Variable-temperature and -field magnetization (M) data were collected in the 1.8-4.0 K and 0.1-7 T ranges and fit by matrix diagonalization assuming only the ground state is occupied at these temperatures. The fit parameters were S = 51/2, D = -0.020(2) cm(-1), and g = 1.87(3), where D is the axial zero-field splitting parameter. Alternating current (ac) susceptibility measurements in the 1.8-8.0 K range and a 3.5 G ac field oscillating at frequencies in the 50-1500 Hz range revealed a frequency-dependent out-of-phase (chi(M)'') signal below 3 K, suggesting 1 to be a single-molecule magnet (SMM). This was confirmed by magnetization vs dc field sweeps, which exhibited hysteresis loops but with no clear steps characteristic of resonant quantum tunneling of magnetization (QTM). However, magnetization decay data below 1 K were collected and used to construct an Arrhenius plot, and the fit of the thermally activated region above approximately 0.5 K gave U(eff)/k = 12 K, where U(eff) is the effective relaxation barrier. The g value and the magnitude and sign of the D value were independently confirmed by detailed high-frequency electron paramagnetic resonance (HFEPR) spectroscopy on polycrystalline samples. The combined studies confirm both the high ground-state spin S = 51/2 of complex 1 and that it is a SMM that, in addition, exhibits QTM.
A detailed proof of the fundamental theorem of STF multipole expansion in linearized gravity
Zschocke, Sven
2014-01-01
The linearized field equations of general relativity in harmonic coordinates are given by an inhomogeneous wave equation. In the region exterior to the matter field, the retarded solution of this wave equation can be expanded in terms of 10 Cartesian symmetric and tracefree (STF) multipoles in post-Minkowskian approximation. For such a multipole decomposition only three and rather weak assumptions are required: 1. No-incoming radiation condition. 2. The matter source is spatially compact. 3. A spherical expansion for the metric outside the matter source is possible. During the last decades, the STF multipole expansion has been established as a powerful tool in several fields of gravitational physics: celestial mechanics, theory of gravitational waves and in the theory of light propagation and astrometry. But despite its formidable importance, an explicit proof of the fundamental theorem of STF multipole expansion has not been presented thus far, while only some parts of it are distributed into several publica...
Review of non-Gaussianity at low and high multipoles from WMAP data
Verkhodanov, O. V.; Naselsky, P. D.; Chiang, L.-Y.; Doroshkevich, A. G.; Novikov, I. D.
2008-09-01
We review problems of non-Gaussianity analysis of the WMAP data. The non-Gaussianity has been detected by different methods in several multipole ranges. To our opinion, it could be due to some systematic effects of data analysis.
Adaptation and performance of the fast multipole method for dipolar systems
Gorn, N.L. E-mail: db@innovent-jena.de; Berkov, D.V
2004-05-01
We have developed a new specialized version of the fast multipole method (FMM) for dipolar systems. For this purpose we have derived general expressions of the multipole expansion coefficients (in spherical coordinates) for a system of point dipoles with the potential phi (cursive,open) Greek{sub dip}{approx}1/r{sup 2}. Our version is especially useful for simulations of fine magnetic particle systems (magnetic nanocomposites, ferrofluids), molecular dipolar fluids or electric dipolar glasses.
Polarizable atomic multipole X-ray refinement: application to peptide crystals
Schnieders, Michael J. [Department of Chemistry, Stanford, CA 94305 (United States); Fenn, Timothy D. [Department of Molecular and Cellular Physiology, Stanford, CA 94305 (United States); Howard Hughes Medical Institute (United States); Pande, Vijay S., E-mail: pande@stanford.edu [Department of Chemistry, Stanford, CA 94305 (United States); Brunger, Axel T., E-mail: pande@stanford.edu [Department of Molecular and Cellular Physiology, Stanford, CA 94305 (United States); Howard Hughes Medical Institute (United States); Department of Chemistry, Stanford, CA 94305 (United States)
2009-09-01
A method to accelerate the computation of structure factors from an electron density described by anisotropic and aspherical atomic form factors via fast Fourier transformation is described for the first time. Recent advances in computational chemistry have produced force fields based on a polarizable atomic multipole description of biomolecular electrostatics. In this work, the Atomic Multipole Optimized Energetics for Biomolecular Applications (AMOEBA) force field is applied to restrained refinement of molecular models against X-ray diffraction data from peptide crystals. A new formalism is also developed to compute anisotropic and aspherical structure factors using fast Fourier transformation (FFT) of Cartesian Gaussian multipoles. Relative to direct summation, the FFT approach can give a speedup of more than an order of magnitude for aspherical refinement of ultrahigh-resolution data sets. Use of a sublattice formalism makes the method highly parallelizable. Application of the Cartesian Gaussian multipole scattering model to a series of four peptide crystals using multipole coefficients from the AMOEBA force field demonstrates that AMOEBA systematically underestimates electron density at bond centers. For the trigonal and tetrahedral bonding geometries common in organic chemistry, an atomic multipole expansion through hexadecapole order is required to explain bond electron density. Alternatively, the addition of interatomic scattering (IAS) sites to the AMOEBA-based density captured bonding effects with fewer parameters. For a series of four peptide crystals, the AMOEBA–IAS model lowered R{sub free} by 20–40% relative to the original spherically symmetric scattering model.
Fast Multipole-Based Elliptic PDE Solver and Preconditioner
Ibeid, Huda
2016-12-07
Exascale systems are predicted to have approximately one billion cores, assuming Gigahertz cores. Limitations on affordable network topologies for distributed memory systems of such massive scale bring new challenges to the currently dominant parallel programing model. Currently, there are many efforts to evaluate the hardware and software bottlenecks of exascale designs. It is therefore of interest to model application performance and to understand what changes need to be made to ensure extrapolated scalability. Fast multipole methods (FMM) were originally developed for accelerating N-body problems for particle-based methods in astrophysics and molecular dynamics. FMM is more than an N-body solver, however. Recent efforts to view the FMM as an elliptic PDE solver have opened the possibility to use it as a preconditioner for even a broader range of applications. In this thesis, we (i) discuss the challenges for FMM on current parallel computers and future exascale architectures, with a focus on inter-node communication, and develop a performance model that considers the communication patterns of the FMM for spatially quasi-uniform distributions, (ii) employ this performance model to guide performance and scaling improvement of FMM for all-atom molecular dynamics simulations of uniformly distributed particles, and (iii) demonstrate that, beyond its traditional use as a solver in problems for which explicit free-space kernel representations are available, the FMM has applicability as a preconditioner in finite domain elliptic boundary value problems, by equipping it with boundary integral capability for satisfying conditions at finite boundaries and by wrapping it in a Krylov method for extensibility to more general operators. Compared with multilevel methods, FMM is capable of comparable algebraic convergence rates down to the truncation error of the discretized PDE, and it has superior multicore and distributed memory scalability properties on commodity
Iwamoto, C.; Utsunomiya, H.; Tamii, A.; Akimune, H.; Nakada, H.; Shima, T.; Yamagata, T.; Kawabata, T.; Fujita, Y.; Matsubara, H.; Shimbara, Y.; Nagashima, M.; Suzuki, T.; Fujita, H.; Sakuda, M.; Mori, T.; Izumi, T.; Okamoto, A.; Kondo, T.; Bilgier, B.; Kozer, H. C.; Lui, Y.-W.; Hatanaka, K.
2012-06-01
A high-resolution measurement of inelastic proton scattering off Zr90 near 0° was performed at 295 MeV with a focus on a pronounced strength previously reported in the low-energy tail of giant dipole resonance. A forest of fine structure was observed in the excitation energy region 7-12 MeV. A multipole decomposition analysis of the angular distribution for the forest was carried out using the ECIS95 distorted-wave Born approximation code with the Hartree-Fock plus random-phase approximation model of E1 and M1 transition densities and inclusion of E1 Coulomb excitation. The analysis separated pygmy dipole and M1 resonances in the forest at EPDR=9.15±0.18MeV with ΓPDR=2.91±0.64MeV and at EM1=9.53±0.06MeV with ΓM1=2.70±0.17MeV in the Lorentzian function, respectively. The B(E1)↑ value for pygmy dipole resonance over 7-11 MeV is 0.75±0.08e2fm2, which corresponds to 2.1±0.2% of the Thomas-Reiche-Kuhn sum rule.
S. Bagchi
2015-12-01
Full Text Available The Isoscalar Giant Monopole Resonance (ISGMR and the Isoscalar Giant Dipole Resonance (ISGDR compression modes have been studied in the doubly-magic unstable nucleus 56Ni. They were measured by inelastic α-particle scattering in inverse kinematics at 50 MeV/u with the MAYA active target at the GANIL facility. The centroid of the ISGMR has been obtained at Ex=19.1±0.5 MeV. Evidence for the low-lying part of the ISGDR has been found at Ex=17.4±0.7 MeV. The strength distribution for the dipole mode shows similarity with the prediction from the Hartree–Fock (HF based random-phase approximation (RPA [1]. These measurements confirm inelastic α-particle scattering as a suitable probe for exciting the ISGMR and the ISGDR modes in radioactive isotopes in inverse kinematics.
High Heat-Load Slits for the PLS Multipole Wiggler
Gil, Kyehwan; Kim, Young-Chan; Lee, Heung-Soo; Wha Chung, Chin
2005-01-01
The HFMX (High Flux Macromolecular X-ray crystallography) beamline under commissioning at Pohang Accelerator Laboratory uses beam from a multipole wiggler for MAD experiment. Two horizontal and vertical slits relevant to high heat load are installed at its front-end. In order to treat high heat load and to reduce beam scattering, the horizontal slit has two glidcop blocks with 10° of vertical inclination and its tungsten blades defining beam size are bolted on backsides of both blocks. The blocks of the slit are adjusted on fixed slides by two actuating bars, respectively. Water through channels machined along the actuating bars cool down the heat load of both blocks. The vertical slit has the same structure as the horizontal slit except its installation direction and angle of vertical inclination. The installed slits show stable operation performance and no alignment for the blocks is required by virtue of a pair of blocks translating on slides. The cooling performance of two slits is also shown to ...
Multipole analysis of redshift-space distortions around cosmic voids
Hamaus, Nico; Cousinou, Marie-Claude; Pisani, Alice; Aubert, Marie; Escoffier, Stéphanie; Weller, Jochen
2017-07-01
We perform a comprehensive redshift-space distortion analysis based on cosmic voids in the large-scale distribution of galaxies observed with the Sloan Digital Sky Survey. To this end, we measure multipoles of the void-galaxy cross-correlation function and compare them with standard model predictions in cosmology. Merely considering linear-order theory allows us to accurately describe the data on the entire available range of scales and to probe void-centric distances down to about 2 h-1Mpc. Common systematics, such as the Fingers-of-God effect, scale-dependent galaxy bias, and nonlinear clustering do not seem to play a significant role in our analysis. We constrain the growth rate of structure via the redshift-space distortion parameter β at two median redshifts, β(bar z=0.32)=0.599+0.134-0.124 and β(bar z=0.54)=0.457+0.056-0.054, with a precision that is competitive with state-of-the-art galaxy-clustering results. While the high-redshift constraint perfectly agrees with model expectations, we observe a mild 2σ deviation at bar z=0.32, which increases to 3σ when the data is restricted to the lowest available redshift range of 0.15
A task parallel implementation of fast multipole methods
Taura, Kenjiro
2012-11-01
This paper describes a task parallel implementation of ExaFMM, an open source implementation of fast multipole methods (FMM), using a lightweight task parallel library MassiveThreads. Although there have been many attempts on parallelizing FMM, experiences have almost exclusively been limited to formulation based on flat homogeneous parallel loops. FMM in fact contains operations that cannot be readily expressed in such conventional but restrictive models. We show that task parallelism, or parallel recursions in particular, allows us to parallelize all operations of FMM naturally and scalably. Moreover it allows us to parallelize a \\'\\'mutual interaction\\'\\' for force/potential evaluation, which is roughly twice as efficient as a more conventional, unidirectional force/potential evaluation. The net result is an open source FMM that is clearly among the fastest single node implementations, including those on GPUs; with a million particles on a 32 cores Sandy Bridge 2.20GHz node, it completes a single time step including tree construction and force/potential evaluation in 65 milliseconds. The study clearly showcases both programmability and performance benefits of flexible parallel constructs over more monolithic parallel loops. © 2012 IEEE.
On the origin dependence of multipole moments in electromagnetism
Visschere, Patrick De [Ghent University, Department ELIS Sint-Pietersnieuwstraat 41, B-9000 Gent (Belgium)
2006-10-07
The standard description of material media in electromagnetism is based on multipoles. It is well known that these moments depend on the point of reference chosen, except for the lowest order. It is shown that this 'origin dependence' is not unphysical as has been claimed in the literature but forms only part of the effect of moving the point of reference. When the complementary part is also taken into account then different points of reference lead to different but equivalent descriptions of the same physical reality. This is shown at the microscopic as well as at the macroscopic level. A similar interpretation is valid regarding the 'origin dependence' of the reflection coefficients for reflection on a semi-infinite medium. We show that the 'transformation theory' which has been proposed to remedy this situation (and which is thus not needed) is unphysical since the transformation considered does not leave the boundary conditions invariant.
Data-driven execution of fast multipole methods
Ltaief, Hatem
2013-09-17
Fast multipole methods (FMMs) have O (N) complexity, are compute bound, and require very little synchronization, which makes them a favorable algorithm on next-generation supercomputers. Their most common application is to accelerate N-body problems, but they can also be used to solve boundary integral equations. When the particle distribution is irregular and the tree structure is adaptive, load balancing becomes a non-trivial question. A common strategy for load balancing FMMs is to use the work load from the previous step as weights to statically repartition the next step. The authors discuss in the paper another approach based on data-driven execution to efficiently tackle this challenging load balancing problem. The core idea consists of breaking the most time-consuming stages of the FMMs into smaller tasks. The algorithm can then be represented as a directed acyclic graph where nodes represent tasks and edges represent dependencies among them. The execution of the algorithm is performed by asynchronously scheduling the tasks using the queueing and runtime for kernels runtime environment, in a way such that data dependencies are not violated for numerical correctness purposes. This asynchronous scheduling results in an out-of-order execution. The performance results of the data-driven FMM execution outperform the previous strategy and show linear speedup on a quad-socket quad-core Intel Xeon system.Copyright © 2013 John Wiley & Sons, Ltd. Copyright © 2013 John Wiley & Sons, Ltd.
Fast multipole method applied to Lagrangian simulations of vortical flows
Ricciardi, Túlio R.; Wolf, William R.; Bimbato, Alex M.
2017-10-01
Lagrangian simulations of unsteady vortical flows are accelerated by the multi-level fast multipole method, FMM. The combination of the FMM algorithm with a discrete vortex method, DVM, is discussed for free domain and periodic problems with focus on implementation details to reduce numerical dissipation and avoid spurious solutions in unsteady inviscid flows. An assessment of the FMM-DVM accuracy is presented through a comparison with the direct calculation of the Biot-Savart law for the simulation of the temporal evolution of an aircraft wake in the Trefftz plane. The role of several parameters such as time step restriction, truncation of the FMM series expansion, number of particles in the wake discretization and machine precision is investigated and we show how to avoid spurious instabilities. The FMM-DVM is also applied to compute the evolution of a temporal shear layer with periodic boundary conditions. A novel approach is proposed to achieve accurate solutions in the periodic FMM. This approach avoids a spurious precession of the periodic shear layer and solutions are shown to converge to the direct Biot-Savart calculation using a cotangent function.
Infrared Extrapolations of Electromagnetic Multipole Moments and Transitions
Odell, Daniel; Papenbrock, Thomas; Platter, Lucas
2017-01-01
Basis truncations introduce systematic errors in observables calculated by representing the nuclear Hamiltonian in finite Hilbert spaces. Recent studies of the infrared convergence of finite basis calculations of energies and radii have led to accurate descriptions of numerical data. I will discuss how these concepts can be applied to the study of bound-state quadrupole moments and transitions as well as multipole transitions between bound-states and the continuum. I will show that good agreement is obtained between analytically derived and numerically computed convergence behavior in finite harmonic oscillator spaces for the nucleon-nucleon system. This opens the way to a more precise understanding of structure and reactions involving heavier nuclei. U.S. Dept of Energy, Office of Science under Nos. DEFG02-96ER40963, DE-AC05-00OR22725, DE-SC0008499; US-Israel Binational Science Foundation under Grant No. 2012212; National Science Foundation under Grant No. PHY-1516077 and No. PHY-1555030.
Scalable fast multipole methods for vortex element methods
Hu, Qi
2012-11-01
We use a particle-based method to simulate incompressible flows, where the Fast Multipole Method (FMM) is used to accelerate the calculation of particle interactions. The most time-consuming kernelsâ\\'the Biot-Savart equation and stretching term of the vorticity equationâ\\'are mathematically reformulated so that only two Laplace scalar potentials are used instead of six, while automatically ensuring divergence-free far-field computation. Based on this formulation, and on our previous work for a scalar heterogeneous FMM algorithm, we develop a new FMM-based vortex method capable of simulating general flows including turbulence on heterogeneous architectures, which distributes the work between multi-core CPUs and GPUs to best utilize the hardware resources and achieve excellent scalability. The algorithm also uses new data structures which can dynamically manage inter-node communication and load balance efficiently but with only a small parallel construction overhead. This algorithm can scale to large-sized clusters showing both strong and weak scalability. Careful error and timing trade-off analysis are also performed for the cutoff functions induced by the vortex particle method. Our implementation can perform one time step of the velocity+stretching for one billion particles on 32 nodes in 55.9 seconds, which yields 49.12 Tflop/s. © 2012 IEEE.
Revised Parameters for the AMOEBA Polarizable Atomic Multipole Water Model.
Laury, Marie L; Wang, Lee-Ping; Pande, Vijay S; Head-Gordon, Teresa; Ponder, Jay W
2015-07-23
A set of improved parameters for the AMOEBA polarizable atomic multipole water model is developed. An automated procedure, ForceBalance, is used to adjust model parameters to enforce agreement with ab initio-derived results for water clusters and experimental data for a variety of liquid phase properties across a broad temperature range. The values reported here for the new AMOEBA14 water model represent a substantial improvement over the previous AMOEBA03 model. The AMOEBA14 model accurately predicts the temperature of maximum density and qualitatively matches the experimental density curve across temperatures from 249 to 373 K. Excellent agreement is observed for the AMOEBA14 model in comparison to experimental properties as a function of temperature, including the second virial coefficient, enthalpy of vaporization, isothermal compressibility, thermal expansion coefficient, and dielectric constant. The viscosity, self-diffusion constant, and surface tension are also well reproduced. In comparison to high-level ab initio results for clusters of 2-20 water molecules, the AMOEBA14 model yields results similar to AMOEBA03 and the direct polarization iAMOEBA models. With advances in computing power, calibration data, and optimization techniques, we recommend the use of the AMOEBA14 water model for future studies employing a polarizable water model.
Scoring multipole electrostatics in condensed-phase atomistic simulations.
Bereau, Tristan; Kramer, Christian; Monnard, Fabien W; Nogueira, Elisa S; Ward, Thomas R; Meuwly, Markus
2013-05-09
Permanent multipoles (MTPs) embody a natural extension to common point-charge (PC) representations in atomistic simulations. In this work, we propose an alternative to the computationally expensive MTP molecular dynamics simulations by running a simple PC simulation and later reevaluate-"score''-all energies using the more detailed MTP force field. The method, which relies on the assumption that the PC and MTP force fields generate closely related phase spaces, is accomplished by enforcing identical sets of monopoles between the two force fields-effectively highlighting the higher MTP terms as a correction to the PC approximation. We first detail our consistent parametrization of the electrostatics and van der Waals interactions for the two force fields. We then validate the method by comparing the accuracy of protein-ligand binding free energies from both PC and MTP-scored representations with experimentally determined binding constants obtained by us. Specifically, we study the binding of several arylsulfonamide ligands to human carbonic anhydrase II. We find that both representations yield an accuracy of 1 kcal/mol with respect to experiment. Finally, we apply the method to rank the energetic contributions of individual atomic MTP coefficients for molecules solvated in water. All in all, MTP scoring is a computationally appealing method that can provide insight into the multipolar electrostatic interactions of condensed-phase systems.
Instability of reconstruction of the low CMB multipoles
Naselsky, Pavel D.; Verkhodanov, Oleg V.; Nielsen, Mikkel T. B.
2007-01-01
We discuss the problem of the bias of the Internal Linear Combination (ILC) CMB map and show that it is closely related to the coefficient of cross-correlation K(l) of the true CMB and the foreground for each multipole l. We present analysis of the cross-correlation for the WMAP ILC quadrupole...... and octupole from the first (ILC(I)) and the third (ILC(III)) year data releases and show that these correlations are about -0.52-0.6. Analysing 10^4 Monte Carlo simulations of the random Gaussian CMB signals, we show that the distribution function for the corresponding coefficient of the cross-correlation has...... of debiasing of the ILC CMB and pointed out that reconstruction of the bias seems to be very problematic due to statistical uncertainties. In addition, instability of the debiasing illuminates itself for the quadrupole and octupole components through the flip-effect, when the even (l+m) modes can...
United polarizable multipole water model for molecular mechanics simulation
Qi, Rui; Wang, Qiantao; Ren, Pengyu, E-mail: pren@mail.utexas.edu [Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas 78712 (United States); Wang, Lee-Ping; Pande, Vijay S. [Department of Chemistry, Stanford University, Stanford, California 94305 (United States)
2015-07-07
We report the development of a united AMOEBA (uAMOEBA) polarizable water model, which is computationally 3–5 times more efficient than the three-site AMOEBA03 model in molecular dynamics simulations while providing comparable accuracy for gas-phase and liquid properties. In this coarse-grained polarizable water model, both electrostatic (permanent and induced) and van der Waals representations have been reduced to a single site located at the oxygen atom. The permanent charge distribution is described via the molecular dipole and quadrupole moments and the many-body polarization via an isotropic molecular polarizability, all located at the oxygen center. Similarly, a single van der Waals interaction site is used for each water molecule. Hydrogen atoms are retained only for the purpose of defining local frames for the molecular multipole moments and intramolecular vibrational modes. The parameters have been derived based on a combination of ab initio quantum mechanical and experimental data set containing gas-phase cluster structures and energies, and liquid thermodynamic properties. For validation, additional properties including dimer interaction energy, liquid structures, self-diffusion coefficient, and shear viscosity have been evaluated. The results demonstrate good transferability from the gas to the liquid phase over a wide range of temperatures, and from nonpolar to polar environments, due to the presence of molecular polarizability. The water coordination, hydrogen-bonding structure, and dynamic properties given by uAMOEBA are similar to those derived from the all-atom AMOEBA03 model and experiments. Thus, the current model is an accurate and efficient alternative for modeling water.
Multipole Matrix Elements for Dh-Systems and Their Asymptotics
Tarasov, V. F.
A “DH-system” is defined as a multidimensional hydrogen atom (or its one-particle analogue), D≥1. Investigating many Coulomb problems in ℝD it is necessary to know exact analytical expressions of multipole matrix elements D for DH-systems, where q=(N, µ) is a set of parameters, N —"principal” and µ — "orbital” quantum numbers. The paper deals with the new method for the evaluation of similar matrix elements using new properties of Appell’s function F2(x, y) to the vicinity of the singular point (1, 1). Such approach allows: 1) to get exact analytical expressions of these matrix elements (considering the selection rules) by means of Appell’s F2 (or Clausen’s 3F2) functions; 2) to reveal “latent” symmetry of diagonal matrix elements with respect to the point k0=-3/2, the above symmetry is connected with the property of Appell’s function F2 (1,1) mirror-like symmetry; 3) to find (exact) asymptotics of the off-diagonal matrix elements in terms of Horn’s function ψ1 (x, y); 4) to prove that the orthogonality of radial functions fNµ (D, r) over N and μ for DH-systems is connected with the properties of Appell’s F2 function to the vicinity of the singular point (1, 1), it generalizes the known result for 3H-atom by Pasternack and Sternheimer, J. Math. Phys. 3, 1280 (1962).
a Detailed Proof of the Fundamental Theorem of STF Multipole Expansion in Linearized Gravity
Zschocke, Sven
2014-10-01
The linearized field equations of general relativity in harmonic coordinates are given by an inhomogeneous wave equation. In the region exterior to the matter field, the retarded solution of this wave equation can be expanded in terms of 10 Cartesian symmetric and tracefree (STF) multipoles in post-Minkowskian approximation. For such a multipole decomposition only three and rather weak assumptions are required: (1) No-incoming-radiation condition. (2) The matter source is spatially compact. (3) A spherical expansion for the metric outside the matter source is possible. During the last decades, the STF multipole expansion has been established as a powerful tool in several fields of gravitational physics: celestial mechanics, theory of gravitational waves and in the theory of light propagation and astrometry. But despite its formidable importance, an explicit proof of the fundamental theorem of STF multipole expansion has not been presented so far, while only some parts of it are distributed into several publications. In a technical but more didactical form, an explicit and detailed mathematical proof of each individual step of this important theorem of STF multipole expansion is represented.
Chang-Jun Zheng; Hai-Bo Chen; Lei-Lei Chen
2013-01-01
This paper presents a novel wideband fast multipole boundary element approach to 3D half-space/planesymmetric acoustic wave problems.The half-space fundamental solution is employed in the boundary integral equations so that the tree structure required in the fast multipole algorithm is constructed for the boundary elements in the real domain only.Moreover,a set of symmetric relations between the multipole expansion coefficients of the real and image domains are derived,and the half-space fundamental solution is modified for the purpose of applying such relations to avoid calculating,translating and saving the multipole/local expansion coefficients of the image domain.The wideband adaptive multilevel fast multipole algorithm associated with the iterative solver GMRES is employed so that the present method is accurate and efficient for both lowand high-frequency acoustic wave problems.As for exterior acoustic problems,the Burton-Miller method is adopted to tackle the fictitious eigenfrequency problem involved in the conventional boundary integral equation method.Details on the implementation of the present method are described,and numerical examples are given to demonstrate its accuracy and efficiency.
... Cryopyrin-Associated Autoinflammatory Syndrome (CAPS) (Juvenile) Dermatomyositis (Juvenile) Familial Mediterranean Fever (Juvenile) Fibromyalgia Giant Cell Arteritis Glucocorticoid-induced Osteoperosis ...
Nanodielectrics with giant permittivity
S K Saha
2008-06-01
Nanodielectrics is an emerging area of research because of its potential application in energy storage and transducers. One-dimensional metallic nanostructures with localized electronic wave functions show giant dielectric constant. Following the prediction, during the last couple of years we have investigated the effect of giant permittivity in one-dimensional systems of conventional metals and conjugated polymer chains. In this article, we have tried to summarize the works on giant permittivity and finally the fabrication of nanocapacitor using metal nanowires, which shows giant permittivity is also discussed.
Self-similar oscillations of a Z pinch bounded by a magnetic multipole
Tendler, M.
1988-11-01
A new analytic, self-similar solution of the fluid equations with losses in a stabilized Z pinch is presented. A scaling is suggested for the net energy loss with plasma density and temperature typical for a Z pinch immersed in an external multipole magnetic field. The solution of the strongly nonlinear system of fluid equations is obtained by self-similar methods. Strongly aharmonic high frequency oscillations of the plasma parameters are found. It is emphasized that a static Z pinch cannot be stabilized by a stationary field of a magnetic multipole. Therefore the potentiality of these oscillations to affect the stability of Z pinches embedded in a magnetic multipole is investigated. The effect of the dynamic stabilization is considered by taking estimates.
Multipole analysis for electromagnetism and linearized gravity with irreducible Cartesian tensors
Damour, T.; Iyer, B.R. (Institut des Hautes Etudes Scientifiques 91440 Bures sur Yvette, France Departement d' Astrophysique Relativiste et de Cosmologie, Centre National de la Recherche Scientifique-Observatoire de Paris, 92195 Meudon CEDEX, France (FR))
1991-05-15
The relativistic time-dependent multipole expansion for electromagnetism and linearized gravity in the region outside a spatially compact source has been obtained directly using the formalism of irreducible Cartesian (i.e., symmetric trace-free) tensors. In the electromagnetic case, our results confirm the validity of the results obtained earlier by Campbell, Macek, and Morgan using the Debye potential formalism. However, in the more complicated linearized gravity case, the greater algebraic transparence of the Cartesian multipole approach has allowed us to obtain, for the first time, fully correct closed-form expressions for the time-dependent mass and spin multipole moments (the results of Campbell {ital et} {ital al}. for the mass moments turning out to be incorrect). The first two terms in the slow-motion expansion of the gravitational moments are explicitly calculated and shown to be equivalent to earlier results by Thorne and by Blanchet and Damour.
Kanduc, M; Podgornik, R [Department of Theoretical Physics, J Stefan Institute, SI-1000 Ljubljana (Slovenia); Naji, A [Department of Physics, Department of Chemistry and Biochemistry, Materials Research Laboratory, University of California, Santa Barbara, CA 93106 (United States); Jho, Y S; Pincus, P A [Materials Research Laboratory, University of California, Santa Barbara, CA 93106 (United States)
2009-10-21
We present general arguments for the importance, or lack thereof, of structure in the charge distribution of counterions for counterion-mediated interactions between bounding symmetrically charged surfaces. We show that on the mean field or weak coupling level, the charge quadrupole contributes the lowest order modification to the contact value theorem and thus to the intersurface electrostatic interactions. The image effects are non-existent on the mean field level even with multipoles. On the strong coupling level the quadrupoles and higher order multipoles contribute additional terms to the interaction free energy only in the presence of dielectric inhomogeneities. Without them, the monopole is the only multipole that contributes to the strong coupling electrostatics. We explore the consequences of these statements in all their generality.
Multipole correction of atomic monopole models of molecular charge distribution. I. Peptides
Sokalski, W. A.; Keller, D. A.; Ornstein, R. L.; Rein, R.
1993-01-01
The defects in atomic monopole models of molecular charge distribution have been analyzed for several model-blocked peptides and compared with accurate quantum chemical values. The results indicate that the angular characteristics of the molecular electrostatic potential around functional groups capable of forming hydrogen bonds can be considerably distorted within various models relying upon isotropic atomic charges only. It is shown that these defects can be corrected by augmenting the atomic point charge models by cumulative atomic multipole moments (CAMMs). Alternatively, sets of off-center atomic point charges could be automatically derived from respective multipoles, providing approximately equivalent corrections. For the first time, correlated atomic multipoles have been calculated for N-acetyl, N'-methylamide-blocked derivatives of glycine, alanine, cysteine, threonine, leucine, lysine, and serine using the MP2 method. The role of the correlation effects in the peptide molecular charge distribution are discussed.
A SMALL UNBALANCED MAGNETRON SPUTTERING SOURCE WITH MULTIPOLE MAGNETIC FIELD ANODE
郑思孝; 孙官清; 等
1994-01-01
A small unbalanced magnetron atom source with multipole cusp magnetic field anode is described.The co-axial magnetron rpinciple is extended to the circular planar magnetron atom source,which raises the efficiency of sputtering target area up to 60%.The multipole magnetic field is put in the anode.which makes the unbalanced magnetron atom source run in a higher discharge current at a lower arc voltage condition.Meanwhile.the sputtering atoms through out the anode can be ionized partially,because the electron reaching the anode have to suffer multiple collisons in order to advance across the multipole magnetic field lines in the anode,which enhances the chemical reactivity of the ejecting atoms in film growth and improve the property of film depositing.
Platonic topology and CMB fluctuations: Homotopy, anisotropy, and multipole selection rules
Kramer, Peter
2009-01-01
The Cosmic Microwave Background CMB originates from an early stage in the history of the universe. Observed low multipole contributions of CMB fluctuations have motivated the search for selection rules from the underlying topology of 3-space. Everitt (2004) has generated all homotopies for Platonic spherical 3-manifolds by face gluings. We transform the glue generators into isomorphic deck transformations. The deck transformations act on a spherical Platonic 3-manifold as prototile and tile the 3-sphere by its images. A complete set of orthonormal functions on the 3-sphere is spanned by the Wigner harmonic polynomials. For a tetrahedral, two cubic and three octahedral manifolds we construct algebraically linear combinations of Wigner polynomials, invariant under deck transformations and with domain the manifold. We prove boundary conditions on polyhedral faces from homotopy. By algebraic means we pass to a multipole expansion. Assuming random models of the CMB radiation, we derive multipole selection rules, d...
Metin Orbay; Telhat Ozdogan
2001-01-01
As an example of the use of the analytical formulas derived for electric multipole moment integrals over STOs in our previous work (I.L Guseinov,et al.,J.Mol.Struct.(Theochem) 465 (1999) 5),the 2v-pole electric moments have been calculated for the ground electronic states of LiH,BH and FH of the first-row diatomic hydride molecules. Calculated electric multipole moment values are in agreement with literatures.By the use of these analytical formulas the 2v -pole moments for multiatomic molecules can be evaluated most efficiently and accurately by employing STOs as basis sets.
Wang, Z.; Lupo, J.; Patnaik, S.S.; McKenney, A.; Pachter, R.
1999-07-01
The Fast Multipole Method (FMM) offers an efficient way (order O(N)) to handle long range electrostatic interactions, thus enabling more realistic molecular dynamics simulations of large molecular systems. The performance of the fast molecular dynamics (FMD) code, a parallel MD code being developed in the group, using the three-dimensional fast multipole method, shows a good speedup. The application to the full atomic-scale molecular dynamics simulation of a liquid crystalline droplet of 4-n-pentyl-4{prime}-cyanobiphenyl (5CB) molecules, of size 35,872 atoms, shows strong surface effects on various orientational order parameters.
Termination shock thermal processes as a possible source for the CMB low-order multipole anomalies
2009-01-01
We discuss the possibility that the observed low-order multipole features of the cosmic microwave background radiation (CMB) all originate in the termination shock (TS) region of the heliosheath that surrounds the solar system. If the intrinsic CMB spectrum is assumed to be a pure monopole (2.73K) then thermodynamic processes occurring within the plasma region of the TS could imprint the observed power spectrum of the low-order multipoles and their alignment (the so-called "axis of evil") ont...
A. Schroeder
2012-09-01
Full Text Available This paper proposes a compression of far field matrices in the fast multipole method and its multilevel extension for electromagnetic problems. The compression is based on a spherical harmonic representation of radiation patterns in conjunction with a radiating mode expression of the surface current. The method is applied to study near field effects and the far field of an antenna placed on a ship surface. Furthermore, the electromagnetic scattering of an electrically large plate is investigated. It is demonstrated, that the proposed technique leads to a significant memory saving, making multipole algorithms even more efficient without compromising the accuracy.
Fast Multipole BEM for 3-D Elastostatic Problems with Applications for Thin Structures
ZHAO Libin; YAO Zhenhan
2005-01-01
The fast multipole method (FMM) has been used to reduce the computing operations and memory requirements in large numerical analysis problems. In this paper, the FMM based on Taylor expansions is combined with the boundary element method (BEM) for three-dimensional elastostatic problems to solve thin plate and shell structures. The fast multipole boundary element method (FM-BEM) requires O(N) operations and memory for problems with N unknowns. The numerical results indicate that for the analysis of thin structures, the FM-BEM is much more efficient than the conventional BEM and the accuracy achieved is sufficient for engineering applications.
Multipole Field Effects for the Superconducting Parallel-Bar Deflecting/Crabbing Cavities
De Silva, Payagalage Subashini Uddika [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States) and Old Dominion University, Norfolk, VA (United States); Delayen, Jean Roger [Old Dominion University, Norfolk, VA (United States)
2012-09-01
The superconducting parallel-bar deflecting/crabbing cavity is currently being considered as one of the design options in rf separation for the Jefferson Lab 12 GeV upgrade and for the crabbing cavity for the proposed LHC luminosity upgrade. Knowledge of multipole field effects is important for accurate beam dynamics study of rf structures. The multipole components can be accurately determined numerically using the electromagnetic surface field data in the rf structure. This paper discusses the detailed analysis of those components for the fundamental deflecting/crabbing mode and higher order modes in the parallel-bar deflecting/crabbing cavity.
Effects of Crab Cavities' Multipole Content in an Electron-Ion Collider
Satogata, Todd J. [Jefferson Lab., Newport News, VA (United States); Morozov, Vasiliy [Jefferson Lab., Newport News, VA (United States); Delayen, Jean R. [Old Dominion Univ., Norfolk, VA (United States); Jefferson Lab., Newport News, VA (United States); Castillo, Alejandro [Old Dominion Univ., Norfolk, VA (United States)
2015-09-01
The impact on the beam dynamics of the Medium Energy Electron-Ion Colider (MEIC) due to the multipole content of the 750 MHz crab cavity was studied using thin multipole elements for 6D phase space particle tracking in ELEGANT. Target values of the sextupole component for the cavity’s field expansion were used to perform preliminary studies on the proton beam stability when compared to the case of pure dipole content of the rf kicks. Finally, important effects on the beam sizes due to non-linear components of the crab cavities’ fields were identified, and some criteria for their future study were proposed.
Palmesi, Pietro; Bruckner, Florian; Abert, Claas; Suess, Dieter
2016-01-01
The long-range magnetic field is the most time-consuming part in micromagnetic simulations. Improvements both on a numerical and computational basis can relief problems related to this bottleneck. This work presents an efficient implementation of the Fast Multipole Method [FMM] for the magnetic scalar potential as used in micromagnetics. We assume linearly magnetized tetrahedral sources, treat the near field directly and use analytical integration on the multipole expansion in the far field. This approach tackles important issues like the vectorial and continuous nature of the magnetic field. By using FMM the calculations scale linearly in time and memory.
Geodynamic simulations using the fast multipole boundary element method
Drombosky, Tyler W.
Interaction between viscous fluids models two important phenomena in geophysics: (i) the evolution of partially molten rocks, and (ii) the dynamics of Ultralow-Velocity Zones. Previous attempts to numerically model these behaviors have been plagued either by poor resolution at the fluid interfaces or high computational costs. We employ the Fast Multipole Boundary Element Method, which tracks the evolution of the fluid interfaces explicitly and is scalable to large problems, to model these systems. The microstructure of partially molten rocks strongly influences the macroscopic physical properties. The fractional area of intergranular contact, contiguity, is a key parameter that controls the elastic strength of the grain network in the partially molten aggregate. We study the influence of matrix deformation on the contiguity of an aggregate by carrying out pure shear and simple shear deformations of an aggregate. We observe that the differential shortening, the normalized difference between the major and minor axes of grains is inversely related to the ratio between the principal components of the contiguity tensor. From the numerical results, we calculate the seismic anisotropy resulting from melt redistribution during pure and simple shear deformation. During deformation, the melt is expelled from tubules along three grain corners to films along grain edges. The initially isotropic fractional area of intergranular contact, contiguity, becomes anisotropic due to deformation. Consequently, the component of contiguity evaluated on the plane parallel to the axis of maximum compressive stress decreases. We demonstrate that the observed global shear wave anisotropy and shear wave speed reduction of the Lithosphere-Asthenosphere Boundary are best explained by 0.1 vol% partial melt distributed in horizontal films created by deformation. We use our microsimulation in conjunction with a large scale mantle deep Earth simulation to gain insight into the formation of
Peripheral giant cell granuloma
Padam Narayan Tandon
2012-01-01
Full Text Available Peripheral giant cell granuloma or the so-called "giant cell epulis" is the most common oral giant cell lesion. It normally presents as a soft tissue purplish-red nodule consisting of multinucleated giant cells in a background of mononuclear stromal cells and extravasated red blood cells. This lesion probably does not represent a true neoplasm, but rather may be reactive in nature, believed to be stimulated by local irritation or trauma, but the cause is not certainly known. This article reports a case of peripheral giant cell granuloma arising at the maxillary anterior region in a 22-year-old female patient. The lesion was completely excised to the periosteum level and there is no residual or recurrent swelling or bony defect apparent in the area of biopsy after a follow-up period of 6 months.
Nitadori, Keigo
2014-01-01
We propose an efficient algorithm for the evaluation of the potential and its gradient of gravitational/electrostatic $N$-body systems, which we call particle mesh multipole method (PMMM or PM$^3$). PMMM can be understood both as an extension of the particle mesh (PM) method and as an optimization of the fast multipole method (FMM).In the former viewpoint, the scalar density and potential held by a grid point are extended to multipole moments and local expansions in $(p+1)^2$ real numbers, where $p$ is the order of expansion. In the latter viewpoint, a hierarchical octree structure which brings its $\\mathcal O(N)$ nature, is replaced with a uniform mesh structure, and we exploit the convolution theorem with fast Fourier transform (FFT) to speed up the calculations. Hence, independent $(p+1)^2$ FFTs with the size equal to the number of grid points are performed. The fundamental idea is common to PPPM/MPE by Shimada et al. (1993) and FFTM by Ong et al. (2003). PMMM differs from them in supporting both the open ...
Tilting Saturn without tilting Jupiter: Constraints on giant planet migration
Brasser, R
2015-01-01
The migration and encounter histories of the giant planets in our Solar System can be constrained by the obliquities of Jupiter and Saturn. We have performed secular simulations with imposed migration and N-body simulations with planetesimals to study the expected obliquity distribution of migrating planets with initial conditions resembling those of the smooth migration model, the resonant Nice model and two models with five giant planets initially in resonance (one compact and one loose configuration). For smooth migration, the secular spin-orbit resonance mechanism can tilt Saturn's spin axis to the current obliquity if the product of the migration time scale and the orbital inclinations is sufficiently large (exceeding 30 Myr deg). For the resonant Nice model with imposed migration, it is difficult to reproduce today's obliquity values, because the compactness of the initial system raises the frequency that tilts Saturn above the spin precession frequency of Jupiter, causing a Jupiter spin-orbit resonance...
Computational Study of Plasma Response to a Variable Electric Multipole Configuration
Hicks, Nathaniel
2016-10-01
A computational study is presented of the behavior of a low temperature, quasi-neutral plasma in a three-dimensional, time-varying electric multipole field. A 3-D particle- in-cell (PIC) plasma code is used to simulate the process. The simulations study the effect of the plasma species' mass difference on the plasma response, with the multipole field frequency being chosen, for example, to interact strongly with light particles but negligibly with heavy ones. The effect of focusing the light species to the center of the multipole structure is examined, with space charge neutralized by the presence of the heavy species. The dependence of plasma density on driving field parameters and geometry (order of multipole, shape of equipotential surfaces) is studied, as well as the behavior of the plasma near gyroresonance in the presence of a background magnetic field. The formation and dependences of the RF plasma sheath are studied, as the sheath responds to variation of the plasma and external field characteristics. The results of the computer modeling study are to inform an initial experimental design and study of the same effects. Supported by NSF/DOE Partnership in Basic Plasma Physics and Engineering Award PHY-1619615.
Identifying the Development in Phase and Amplitude of Dipole and Multipole Radiation
Rice, E. M.; Bradshaw, D. S.; Saadi, K.; Andrews, D. L.
2012-01-01
The spatial variation in phase and the propagating wave-front of plane wave electromagnetic radiation are widely familiar text-book territory. In contrast, the developing amplitude and phase of radiation emitted by a dipole or multipole source generally receive less attention, despite the prevalence of these systems. There is additional complexity…
Zarembo, K
2008-01-01
The giant magnons are classical solitons of the O(N) sigma-model, which play an important role in the AdS/CFT correspondence. We study quantum giant magnons first at large N and then exactly using Bethe Ansatz, where giant magnons can be interpreted as holes in the Fermi sea. We also identify a solvable limit of Bethe Ansatz in which it describes a weakly-interacting Bose gas at zero temperature. The examples include the O(N) model at large N, weakly interacting non-linear Schrodinger model, and nearly isotropic XXZ spin chain in the magnetic field.
Busse, F H; 10.1017/S1743921307000920
2009-01-01
Possibilities and difficulties of applying the theory of magnetic field generation by convection flows in rotating spherical fluid shells to the Giant Planets are outlined. Recent progress in the understanding of the distribution of electrical conductivity in the Giant Planets suggests that the dynamo process occurs predominantly in regions of semiconductivity. In contrast to the geodynamo the magnetic field generation in the Giant Planets is thus characterized by strong radial conductivity variations. The importance of the constraint on the Ohmic dissipation provided by the planetary luminosity is emphasized. Planetary dynamos are likely to be of an oscillatory type, although these oscillations may not be evident from the exterior of the planets.
Tahere Nosratzehi; Lale Maleki
2013-01-01
Giant cell fibroma is a fibrous tumor which represents about 2 to 5% of all oral fibrotic proliferations. Compared to traumatic fibroma, giant (traumatic fibroma or irritation fibroma) cell fibroma occurs at a younger age. In about 60% of the cases the lesion is diagnosed within the first three decades of life and is slightly more in women. 50% of the cases is observed in the gum and will appear as a nodule with a papillary surface [1]. The giant cell fibroma is treated by conservative excisi...
Liu, Yangfan; Bolton, J Stuart
2016-08-01
The (Cartesian) multipole series, i.e., the series comprising monopole, dipoles, quadrupoles, etc., can be used, as an alternative to the spherical or cylindrical wave series, in representing sound fields in a wide range of problems, such as source radiation, sound scattering, etc. The proofs of the completeness of the spherical and cylindrical wave series in these problems are classical results, and it is also generally agreed that the Cartesian multipole series spans the same space as the spherical waves: a rigorous mathematical proof of that statement has, however, not been presented. In the present work, such a proof of the completeness of the Cartesian multipole series, both in two and three dimensions, is given, and the linear dependence relations among different orders of multipoles are discussed, which then allows one to easily extract a basis from the multipole series. In particular, it is concluded that the multipoles comprising the two highest orders in the series form a basis of the whole series, since the multipoles of all the lower source orders can be expressed as a linear combination of that basis.
Lin, Jeffrey; Scalo, Carlo; Hesselink, Lambertus
2015-11-01
We have carried out the first high-fidelity Navier-Stokes simulation of a complete thermoacoustic engine with piezoelectric energy extraction. The standing-wave thermoacoustic piezoelectric (TAP) engine model comprises a 51 cm long cylindrical resonator, containing a thermoacoustic stack on one end and capped by a PZT-5A piezoelectric diaphragm on the other end, tuned to the frequency of the thermoacoustically-amplified mode (388 Hz). A multi-pole broadband time-domain impedance model has been adopted to accurately simulate the measured electromechanical properties of the piezoelectric diaphragm. Simulations are first carried out from quasi-quiescent conditions to a limit cycle, with varying temperature gradients and stack configurations. Stack geometry and boundary layers are fully resolved. Acoustic energy extraction is then activated, achieving a new limit cycle at lower pressure amplitudes. The scaling of the modeled electrical power output and attainable thermal-to-electric energy conversion efficiencies are discussed. Limitations of extending a quasi-one-dimensional linear approximation based on Rott's theory to a (low amplitude) limit cycle are discussed, as well as nonlinear effects such as thermoacoustic energy transport and viscous dissipation.
Pereira, L.F.; Hemais, P.M.P.G.; Aymore, I.L.; Carmo, M.C.R. do; Cunha, M.E.P.R. da; Resende, C.M.C.
Three cases of metaphyseal giant cell tumor are presented. A review of the literature is done, demostrating the lesion is rare and that there are few articles about it. Age incidence and characteristics of the tumor are discussed.
Stockdale, Dennis
1998-01-01
Provides directions for the construction of giant plastic cells, including details for building and installing the organelles. Also contains instructions for preparing the ribosomes, nucleolus, nucleus, and mitochondria. (DDR)
Gaulme, Patrick; Schmider, Francois-Xavier; Guillot, Tristan
2014-01-01
Seismology applied to giant planets could drastically change our understanding of their deep interiors, as it has happened with the Earth, the Sun, and many main-sequence and evolved stars. The study of giant planets' composition is important for understanding both the mechanisms enabling their formation and the origins of planetary systems, in particular our own. Unfortunately, its determination is complicated by the fact that their interior is thought not to be homogeneous, so that spectroscopic determinations of atmospheric abundances are probably not representative of the planet as a whole. Instead, the determination of their composition and structure must rely on indirect measurements and interior models. Giant planets are mostly fluid and convective, which makes their seismology much closer to that of solar-like stars than that of terrestrial planets. Hence, helioseismology techniques naturally transfer to giant planets. In addition, two alternative methods can be used: photometry of the solar light ref...
Giant magnetostrictive materials
LIU JingHua; JIANG ChengBao; XU HuiBin
2012-01-01
Giant magnetostrictive materials are a kind of functional materials developed since 1970s,known as their large magnetostrain and high energy density.In this paper,an introduction of magnetosttiction and the history of magnetostrictive materials are described firstly.Then we review the recent developments of both rare earth and non-rare earth magnetostrictive materials.Finally,the tendency of developing new giant magnetostrictive materials is presented.
Red giant seismology: Observations
Mosser B.
2013-03-01
Full Text Available The CoRoT and Kepler missions provide us with thousands of red-giant light curves that allow a very precise asteroseismic study of these objects. Before CoRoT and Kepler, the red-giant oscillation patterns remained obscure. Now, these spectra are much more clear and unveil many crucial interior structure properties. For thousands of red giants, we can derive from seismic data precise estimates of the stellar mass and radius, the evolutionary status of the giants (with a clear difference between clump and RGB stars, the internal differential rotation, the mass loss, the distance of the stars... Analyzing this amount of information is made easy by the identification of the largely homologous red-giant oscillation patterns. For the first time, both pressure and mixed mode oscillation patterns can be precisely depicted. The mixed-mode analysis allows us, for instance, to probe directly the stellar core. Fine details completing the red-giant oscillation pattern then provide further information on the interior structure, including differential rotation.
′Face of the giant panda′ sign in Wilson′s disease : revisited.
Kuruvilla A
2000-10-01
Full Text Available We report a patient, with Wilson′s disease, who showed the characteristic radiological sign known as ′Face of the giant panda sign′ on magnetic resonance imaging (MRI of the brain.
Giant cell tumor of the flexor hallucis longus tendon sheath: a case study.
Findling, Jeff; Lascola, Natalie K; Groner, Thomas W
2011-01-01
Giant cell tumor of tendon sheath is infrequently documented in the foot and even less near the ankle. This case report involves such a tumor of the flexor hallucis longus tendon presenting at the posterior ankle. Diagnosis was aided by magnetic resonance imaging, and treatment consisted of complete surgical excision. Pathologic examination verified the diagnosis of giant cell tumor of tendon sheath, and follow-up magnetic resonance imaging revealed no remnants or recurrence of tumor 1 year after surgery.
Reply to Comment on 'On the origin dependence of multipole moments in electromagnetism'
De Visschere, Patrick [UGent, ELIS, Sint-Pietersnieuwstraat 41, B-9000 Gent (Belgium)
2010-12-22
In this reply, we emphasize that the goal of our original paper was to show that a straightforward application of standard multipole theory does not lead to unphysical results as claimed by Raab and de Lange. We stress once more that an origin shift for calculating the multipoles must be accompanied by a relocation of these multipoles, which compensates the effects of the origin dependence of the multipoles. We point out that the position of the macroscopic boundary is a relevant parameter. We agree that the transformation proposed by Raab and de Lange could still be useful supposing it only affects the phase of the reflected/trasmitted waves. We dispute that the transformation as derived by Raab and de Lange is unique. (reply)
Measurement of inverse pion photoproduction at energies spanning the N ( 1440 ) resonance
Shafi, A.; Prakhov, S.; Strakovsky, I. I.; Briscoe, W. J.; Nefkens, B. M.; Allgower, C. E.; Arndt, R. A.; Bekrenev, V.; Bennhold, C.; Clajus, M.; Comfort, J. R.; Craig, K.; Grosnick, D.; Isenhower, D.; Knecht, N.; Koetke, D. D.; Kulbardis, A.; Kozlenko, N.; Kruglov, S.; Lolos, G.; Lopatin, I.; Manley, D. M.; Manweiler, R.; Marušić, A.; McDonald, S.; Olmsted, J.; Papandreou, Z.; Peaslee, D.; Phaisangittisakul, N.; Price, J. W.; Ramirez, A. F.; Sadler, M.; Spinka, H.; Stanislaus, T. D.; Starostin, A.; Staudenmaier, H. M.; Supek, I.; Tippens, W. B.; Workman, R. L.
2004-09-01
Differential cross sections for the process π- p→γn have been measured at Brookhaven National Laboratory’s Alternating Gradient Synchrotron with the Crystal Ball multiphoton spectrometer. Measurements were made at 18 pion momenta from 238 to 748 MeV/c , corresponding to Eγ for the inverse reaction from 285 to 769 MeV . The data have been used to evaluate the γn multipoles in the vicinity of the N(1440) resonance. We compare our data and multipoles to previous determinations.
Armas, Jay; Obers, Niels A; Orselli, Marta; Pedersen, Andreas Vigand
2012-01-01
We study the giant graviton solution as the AdS_5 X S^5 background is heated up to finite temperature. The analysis employs the thermal brane probe technique based on the blackfold approach. We focus mainly on the thermal giant graviton corresponding to a thermal D3-brane probe wrapped on an S^3 moving on the S^5 of the background at finite temperature. We find several interesting new effects, including that the thermal giant graviton has a minimal possible value for the angular momentum and correspondingly also a minimal possible radius of the S^3. We compute the free energy of the thermal giant graviton in the low temperature regime, which potentially could be compared to that of a thermal state on the gauge theory side. Moreover, we analyze the space of solutions and stability of the thermal giant graviton and find that, in parallel with the extremal case, there are two available solutions for a given temperature and angular momentum, one stable and one unstable. In order to write down the equations of mot...
Gehan, Charlotte; Michel, Eric
2016-01-01
Stellar oscillations give seismic information on the internal properties of stars. Red giants are targets of interest since they present mixed modes, which behave as pressure modes in the convective envelope and as gravity modes in the radiative core. Mixed modes thus directly probe red giant cores, and allow in particular the study of their mean core rotation. The high-quality data obtained by CoRoT and Kepler satellites represent an unprecedented perspective to obtain thousands of measurements of red giant core rotation, in order to improve our understanding of stellar physics in deep stellar interiors. We developed an automated method to obtain such core rotation measurements and validated it for stars on the red giant branch. In this work, we particularly focus on the specific application of this method to red giants having a rapid core rotation. They show complex spectra where it is tricky to disentangle rotational splittings from mixed-mode period spacings. We demonstrate that the method based on the id...
"Bi-modal" isoscalar giant dipole strength in Ni-58
Nayak, B. K.; Garg, U.; Hedden, M.; Koss, M.; Li, T.; Liu, Y.; Rao, P. V. Madhusudhana; Zhu, S.; Itoh, M.; Sakaguchi, H.; Takeda, H.; Uchida, M.; Yasuda, Y.; Yosoi, M.; Fujimura, H.; Fujiwara, M.; Hara, K.; Kawabata, T.; Akimune, H.; Harakeh, M. N.
2006-01-01
The strength distribution of the isoscalar giant dipole resonance (ISGDR) in Ni-58 has been obtained over the energy range 10.5-49.5 MeV via extreme forward angle scattering (including 0 degrees) of 386 MeV alpha particles. We observe a "bi-modal" El strength distribution for the first time in an A
Giant hepatic regenerative nodules in Alagille syndrome
Rapp, Jordan B. [Lewis Katz School of Medicine at Temple University, Department of Radiology, Temple University Hospital, Philadelphia, PA (United States); Bellah, Richard D.; Anupindi, Sudha A. [The Children' s Hospital of Philadelphia, Department of Radiology, Philadelphia, PA (United States); University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA (United States); Maya, Carolina [The Children' s Hospital of Philadelphia, Department of Radiology, Philadelphia, PA (United States); Pawel, Bruce R. [University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA (United States); The Children' s Hospital of Philadelphia, Department of Pathology and Laboratory Medicine, Philadelphia, PA (United States)
2017-02-15
Children with Alagille syndrome undergo surveillance radiologic examinations as they are at risk for developing cirrhosis and hepatocellular carcinoma. There is limited literature on the imaging of liver masses in Alagille syndrome. We report the ultrasound (US) and magnetic resonance imaging (MRI) appearances of incidental benign giant hepatic regenerative nodules in this population. To describe the imaging findings of giant regenerative nodules in patients with Alagille syndrome. A retrospective search of the hospital database was performed to find all cases of hepatic masses in patients with Alagille syndrome during a 10-year period. Imaging, clinical charts, laboratory data and available pathology were reviewed and analyzed and summarized for each patient. Twenty of 45 patients with confirmed Alagille syndrome had imaging studies. Of those, we identified six with giant focal liver masses. All six patients had large central hepatic masses that were remarkably similar on US and MRI, in addition to having features of cirrhosis. In each case, the mass was located in hepatic segment VIII and imaging showed the mass splaying the main portal venous branches at the hepatic hilum, as well as smaller portal and hepatic venous branches coursing through them. On MRI, signal intensity of the mass was isointense to liver on T1-weighted sequences in four of six patients, but hyperintense on T1 in two of six patients. In all six cases, the mass was hypointense on T2- weighted sequences. The mass post-contrast was isointense to adjacent liver in all phases in five the cases. Five out of six patients had pathological correlation demonstrating preserved ductal architecture confirming the final diagnosis of a regenerative nodule. Giant hepatic regenerative nodules with characteristic US and MR features can occur in patients with Alagille syndrome with underlying cirrhosis. Recognizing these lesions as benign giant hepatic regenerative nodules should, thereby, mitigate any need for
The fast multipole method and point dipole moment polarizable force fields
Coles, Jonathan P.; Masella, Michel
2015-01-01
We present an implementation of the fast multipole method for computing Coulombic electrostatic and polarization forces from polarizable force-fields based on induced point dipole moments. We demonstrate the expected O(N) scaling of that approach by performing single energy point calculations on hexamer protein subunits of the mature HIV-1 capsid. We also show the long time energy conservation in molecular dynamics at the nanosecond scale by performing simulations of a protein complex embedded in a coarse-grained solvent using a standard integrator and a multiple time step integrator. Our tests show the applicability of fast multipole method combined with state-of-the-art chemical models in molecular dynamical systems.
Hierarchy of Universal Relations for Neutron Stars in Terms of Multipole Moments
Manko, V S
2016-01-01
Recent studies of the analytical and numerical models of neutron stars strongly suggest that their exterior field can be described by only four arbitrary parameters of the 2-soliton solution of Einstein's equations. Assuming that this is the case, we show that there exists an infinite hierarchy of the universal relations for neutron stars in terms of multipole moments that arises as a series of the degeneration conditions for generic soliton solutions. The simplest of these relations yields a correct expression for the mass-hexadecapole moment as a function of the angular momentum, revealing a need for a more precise definition of this and higher multipole moments in the numerical models of neutron stars.
Termination shock thermal processes as a possible source for the CMB low-order multipole anomalies
Sharpe, H N
2009-01-01
We discuss the possibility that the observed low-order multipole features of the cosmic microwave background radiation (CMB) all originate in the termination shock (TS) region of the heliosheath that surrounds the solar system. If the intrinsic CMB spectrum is assumed to be a pure monopole (2.73K) then thermodynamic processes occurring within the plasma region of the TS could imprint the observed power spectrum of the low-order multipoles and their alignment (the so-called "axis of evil") onto this background isotropic CMB. Conditions are outlined for the geometric shape of the TS region. A key requirement of this model is that the TS plasma be characterized as an optically thin graybody with non-LTE perturbations. Data from the ongoing Voyager missions is critical to this study.
Method of reducing multipole content in a conductor assembly during manufacture
Meinke, Rainer
2016-05-24
A method for manufacture of a conductor assembly. The assembly is of the type which, when conducting current, generates a magnetic field or in which, in the presence of a changing magnetic field, a voltage is induced. In an example embodiment one or more first coil rows are formed. The assembly has multiple coil rows about an axis with outer coil rows formed about inner coil rows. A determination is made of deviations from specifications associated with the formed one or more first coil rows. One or more deviations correspond to a magnitude of a multipole field component which departs from a field specification. Based on the deviations, one or more wiring patterns are generated for one or more second coil rows to be formed about the one or more first coil rows. The one or more second coil rows are formed in the assembly. The magnitude of each multipole field component that departs from the field specification is offset.
Efficient evaluation of antenna fields by a time-domain multipole analysis
J. Adam
2009-05-01
Full Text Available The contribution describes a systematic method to efficiently determine frequency-domain electromagnetic antenna fields and characteristics for a broad spectrum via a single time-domain (e.g., Finite-Difference Time-Domain, FDTD calculation. From a time-domain simulation of an antenna driven by a wide-band signal, a single modified Fourier transformation yields the frequency-domain multipole amplitudes. The corresponding multipole expansions are valid for the entire spectrum of the input pulse and at any point outside a minimum sphere enclosing the antenna. This allows a computationally cheap and elegant post-processing of arbitrary antenna characteristics. As an example of use the method is applied to determine high-resolution three-dimensional radiation patterns of an antipodal Vivaldi antenna.
Local geometry of electromagnetic fields and its role in molecular multipole transitions
Yang, Nan
2010-01-01
Electromagnetic fields with complex spatial variation routinely arise in Nature. We study the response of a small molecule to monochromatic fields of arbitrary three-dimensional geometry. First, we consider the allowed configurations of the fields and field gradients at a single point in space. Many configurations cannot be generated from a single plane wave, regardless of polarization, but any allowed configuration can be generated by superposition of multiple plane waves. There is no local configuration of the fields and gradients that requires near-field effects. Second, we derive a set of local electromagnetic quantities, where each couples to a particular multipole transition. These quantities are small or zero in plane waves, but can be large in regions of certain superpositions of plane waves. Our findings provide a systematic framework for designing far-field and near-field experiments to drive multipole transitions. The proposed experiments provide information on molecular structure that is inaccessi...
Rapid modelling of the redshift-space power spectrum multipoles for a masked density field
Wilson, M. J.; Peacock, J. A.; Taylor, A. N.; de la Torre, S.
2017-01-01
In this work, we reformulate the forward modelling of the redshift-space power spectrum multipole moments for a masked density field, as encountered in galaxy redshift surveys. Exploiting the symmetries of the redshift-space correlation function, we provide a masked-field generalization of the Hankel transform relation between the multipole moments in real and Fourier space. Using this result, we detail how a likelihood analysis requiring computation for a broad range of desired P(k) models may be executed 103-104 times faster than with other common approaches, together with significant gains in spectral resolution. We present a concrete application to the complex angular geometry of the VIMOS Public Extragalactic Redshift Survey PDR-1 release and discuss the validity of this technique for finite-angle surveys.
FRICTIONAL CONTACT MULTIPOLE-BEM AND 3-D ANALYSIS OF SCREWPAIRS
Chen Xiumin; Shen Guangxian; Liu Deyi
2004-01-01
The 3-D traction field in the pressure screw-pair of a 3 500 heavy and medium plate mill press down system is successfully calculated by applying the 3-D frictional contact multipole-BEM and the corresponding program that has been developed. The computing results show the medium diameter orientation is unreliable, especially under the interference of an outer force couple. Under such working conditions, the circumferential traction distribution on the screw teeth is extremely uneven, which is the main reason for the destruction and short life time of screw-pairs. When utilizing the same precision (the relative tolerance is 10×10-5),the mltipole-BEM uses almost the CPU time as used by the FEM,but the needed computer menory size is only one eighieth of that needed by the FEM(10 MB vs.800 MB).The multipole-BEM is well suited for computing large-scale engineering problems.
On the evaluation of molecular dipole moments from multipole refinement of X-ray diffraction data
Abramov, Yu. A.; Volkov, A. V.; Coppens, P.
1999-09-01
Lack of physical constraints in the purely mathematical multipole refinement model can lead to basis set overlap errors in the evaluation of static molecular properties from X-ray diffraction data. For the molecular dipole moment, the error is large for several of the crystals tested in this study: DL-histidine, DL-proline, p-nitroaniline and p-amino- p'-nitrobiphenyl. Two restricted models are tested. In the first, atomic charges are constrained at κ-refinement values, while in the second κ'-values based on multipole refinements of theoretical ab-initio structure factors are used to reduce the flexibility of the model. Both models provide a more localized description of the pseudo atoms compared with an unrestricted refinement, but the κ'-restricted model gives a more consistent representation of the molecular dipole moments and superior agreement with the theoretical deformation density for DL-histidine.
Elking, Dennis M
2016-08-15
New equations for torque and atomic force are derived for use in flexible molecule force fields with atomic multipoles. The expressions are based on Cartesian tensors with arbitrary multipole rank. The standard method for rotating Cartesian tensor multipoles and calculating torque is to first represent the tensor with n indexes and 3(n) redundant components. In this work, new expressions for directly rotating the unique (n + 1)(n + 2)/2 Cartesian tensor multipole components Θpqr are given by introducing Cartesian tensor rotation matrix elements X(R). A polynomial expression and a recursion relation for X(R) are derived. For comparison, the analogous rotation matrix for spherical tensor multipoles are the Wigner functions D(R). The expressions for X(R) are used to derive simple equations for torque and atomic force. The torque and atomic force equations are applied to the geometry optimization of small molecule crystal unit cells. In addition, a discussion of computational efficiency as a function of increasing multipole rank is given for Cartesian tensors. © 2016 Wiley Periodicals, Inc.
Hekker, S
2016-01-01
The internal properties of stars in the red-giant phase undergo significant changes on relatively short timescales. Long near-interrupted high-precision photometric timeseries observations from dedicated space missions such as CoRoT and Kepler have provided seismic inferences of the global and internal properties of a large number of evolved stars, including red giants. These inferences are confronted with predictions from theoretical models to improve our understanding of stellar structure and evolution. Our knowledge and understanding of red giants have indeed increased tremendously using these seismic inferences, and we anticipate that more information is still hidden in the data. Unraveling this will further improve our understanding of stellar evolution. This will also have significant impact on our knowledge of the Milky Way Galaxy as well as on exo-planet host stars. The latter is important for our understanding of the formation and structure of planetary systems.
Multipole electron-density modelling of synchrotron powder diffraction data: the case of diamond
Svendsen, H.; Overgaard, J.; Busselez, R.;
2010-01-01
Accurate structure factors are extracted from synchrotron powder diffraction data measured on crystalline diamond based on a novel multipole model division of overlapping reflection intensities. The approach limits the spherical-atom bias in structure factors extracted from overlapping powder data...... parameter. This directly exposes a correlation between electron density and thermal parameters even for a light atom such as carbon, and it also underlines that in organic systems proper deconvolution of thermal motion is important for obtaining correct static electron densities....
Burt, E. A.; Taghavi-Larigani, S.; Prestage, J. D.; Tjoelker, R. L.
2009-04-01
We have developed a compensated multi-pole Linear Ion Trap Standard (LITS) that eliminates nearly all frequency sensitivity to residual ion number variations. When operated with 199Hg+, this trapped ion clock has recently demonstrated extremely good stability over a 9-month period. The short-term stability has been measured at 5 × 10-14/τ1/2 and an upper limit on long-term fractional frequency deviations of REFID="9789812838223_0037FN001">
Ergul, Ozgur
2014-01-01
The Multilevel Fast Multipole Algorithm (MLFMA) for Solving Large-Scale Computational Electromagnetic Problems provides a detailed and instructional overview of implementing MLFMA. The book: Presents a comprehensive treatment of the MLFMA algorithm, including basic linear algebra concepts, recent developments on the parallel computation, and a number of application examplesCovers solutions of electromagnetic problems involving dielectric objects and perfectly-conducting objectsDiscusses applications including scattering from airborne targets, scattering from red
The Polarizable Atomic Multipole-based AMOEBA Force Field for Proteins.
Shi, Yue; Xia, Zhen; Zhang, Jiajing; Best, Robert; Wu, Chuanjie; Ponder, Jay W; Ren, Pengyu
2013-01-01
Development of the AMOEBA (Atomic Multipole Optimized Energetics for Biomolecular Simulation) force field for proteins is presented. The current version (AMOEBA-2013) utilizes permanent electrostatic multipole moments through the quadrupole at each atom, and explicitly treats polarization effects in various chemical and physical environments. The atomic multipole electrostatic parameters for each amino acid residue type are derived from high-level gas phase quantum mechanical calculations via a consistent and extensible protocol. Molecular polarizability is modeled via a Thole-style damped interactive induction model based upon distributed atomic polarizabilities. Inter- and intramolecular polarization is treated in a consistent fashion via the Thole model. The intramolecular polarization model ensures transferability of electrostatic parameters among different conformations, as demonstrated by the agreement between QM and AMOEBA electrostatic potentials, and dipole moments of dipeptides. The backbone and side chain torsional parameters were determined by comparing to gas-phase QM (RI-TRIM MP2/CBS) conformational energies of dipeptides and to statistical distributions from the Protein Data Bank. Molecular dynamics simulations are reported for short peptides in explicit water to examine their conformational properties in solution. Overall the calculated conformational free energies and J-coupling constants are consistent with PDB statistics and experimental NMR results, respectively. In addition, the experimental crystal structures of a number of proteins are well maintained during molecular dynamics (MD) simulation. While further calculations are necessary to fully validate the force field, initial results suggest the AMOEBA polarizable multipole force field is able to describe the structure and energetics of peptides and proteins, in both gas-phase and solution environments.
White, J.; Phillips, J.R.; Korsmeyer, T. [Massachusetts Institute of Technology, Cambridge, MA (United States)
1994-12-31
Mixed first- and second-kind surface integral equations with (1/r) and {partial_derivative}/{partial_derivative} (1/r) kernels are generated by a variety of three-dimensional engineering problems. For such problems, Nystroem type algorithms can not be used directly, but an expansion for the unknown, rather than for the entire integrand, can be assumed and the product of the singular kernal and the unknown integrated analytically. Combining such an approach with a Galerkin or collocation scheme for computing the expansion coefficients is a general approach, but generates dense matrix problems. Recently developed fast algorithms for solving these dense matrix problems have been based on multipole-accelerated iterative methods, in which the fast multipole algorithm is used to rapidly compute the matrix-vector products in a Krylov-subspace based iterative method. Another approach to rapidly computing the dense matrix-vector products associated with discretized integral equations follows more along the lines of a multigrid algorithm, and involves projecting the surface unknowns onto a regular grid, then computing using the grid, and finally interpolating the results from the regular grid back to the surfaces. Here, the authors describe a precorrectted-FFT approach which can replace the fast multipole algorithm for accelerating the dense matrix-vector product associated with discretized potential integral equations. The precorrected-FFT method, described below, is an order n log(n) algorithm, and is asymptotically slower than the order n fast multipole algorithm. However, initial experimental results indicate the method may have a significant constant factor advantage for a variety of engineering problems.
High-order multipole radiation from quantum Hall states in Dirac materials
Gullans, Michael J.; Taylor, Jacob M.; Imamoǧlu, Ataç; Ghaemi, Pouyan; Hafezi, Mohammad
2017-06-01
We investigate the optical response of strongly disordered quantum Hall states in two-dimensional Dirac materials and find qualitatively different effects in the radiation properties of the bulk versus the edge. We show that the far-field radiation from the edge is characterized by large multipole moments (>50 ) due to the efficient transfer of angular momentum from the electrons into the scattered light. The maximum multipole transition moment is a direct measure of the coherence length of the edge states. Accessing these multipole transitions would provide new tools for optical spectroscopy and control of quantum Hall edge states. On the other hand, the far-field radiation from the bulk appears as random dipole emission with spectral properties that vary with the local disorder potential. We determine the conditions under which this bulk radiation can be used to image the disorder landscape. Such optical measurements can probe submicron-length scales over large areas and provide complementary information to scanning probe techniques. Spatially resolving this bulk radiation would serve as a novel probe of the percolation transition near half filling.
A Dialogue of Multipoles: Matched Asymptotic Expansion for Caged Black Holes
Gorbonos, Dan; Gorbonos, Dan; Kol, Barak
2004-01-01
No analytic solution is known to date for a black hole in a compact dimension. We develop an analytic perturbation theory where the small parameter is the size of the black hole relative to the size of the compact dimension. We set up a general procedure for an arbitrary order in the perturbation series based on an asymptotic matched expansion between two coordinate patches: the near horizon zone and the asymptotic zone. The procedure is ordinary perturbation expansion in each zone, where additionally some boundary data comes from the other zone, and so the procedure alternates between the zones. It can be viewed as a dialogue of multipoles where the black hole changes its shape (mass multipoles) in response to the field (multipoles) created by its periodic "mirrors", and that in turn changes its field and so on. We present the leading correction to the full metric including the first correction to the area-temperature relation, the leading term for black hole eccentricity and the "Archimedes effect". The nex...
A Dialogue of Multipoles: Matched Asymptotic Expansion for Caged Black Holes
Gorbonos, Dan; Kol, Barak
2004-06-01
No analytic solution is known to date for a black hole in a compact dimension. We develop an analytic perturbation theory where the small parameter is the size of the black hole relative to the size of the compact dimension. We set up a general procedure for an arbitrary order in the perturbation series based on an asymptotic matched expansion between two coordinate patches: the near horizon zone and the asymptotic zone. The procedure is ordinary perturbation expansion in each zone, where additionally some boundary data comes from the other zone, and so the procedure alternates between the zones. It can be viewed as a dialogue of multipoles where the black hole changes its shape (mass multipoles) in response to the field (multipoles) created by its periodic ``mirrors'', and that in turn changes its field and so on. We present the leading correction to the full metric including the first correction to the area-temperature relation, the leading term for black hole eccentricity and the ``Archimedes effect''. The next order corrections will appear in a sequel. On the way we determine independently the static perturbations of the Schwarzschild black hole in dimension d geq 5, where the system of equations can be reduced to ``a master equation'' — a single ordinary differential equation. The solutions are hypergeometric functions which in some cases reduce to polynomials.
Gniewek, Piotr
2016-01-01
The conventional surface integral formula $J_{\\rm surf}[\\Phi]$ and an alternative volume integral formula $J_{\\rm var}[\\Phi]$ are used to compute the asymptotic exchange splitting of the interaction energy of the hydrogen atom and a proton employing the primitive function $\\Phi$ in the form of its truncated multipole expansion. Closed-form formulas are obtained for the asymptotics of $J_{\\rm surf}[\\Phi_N]$ and $J_{\\rm var}[\\Phi_N]$, where $\\Phi_N$ is the multipole expansion of $\\Phi$ truncated after the $1/R^N$ term, $R$ being the internuclear separation. It is shown that the obtained sequences of approximations converge to the exact results with the rate corresponding to the convergence radius equal to 2 and 4 when the surface and the volume integral formulas are used, respectively. When the multipole expansion of a truncated, $K$th order polarization function is used to approximate the primitive function the convergence radius becomes equal to unity in the case of $J_{\\textrm{var}}[\\Phi]$. At low order the ...
Giant choledochal calculosis: Surgical treatment
Hasan Bektas
2014-01-01
Full Text Available Context: Gallstone disease is one of the most common surgical pathologies. Choledocholithiasis may occur in some of these cases and require surgical intervention. Although there are relatively non-invasive procedures such as endoscopic retrograde cholangiopancreatography (ERCP, this technique is usually unsuccessful in patients with stones larger than 10 mm. In our case, we aimed to report a giant choledochal stone (15 cm × 4.5 cm, which is rare in surgical practice and our treatment with open surgery. Case Report: The patient was a 59-year-old woman. Magnetic resonance cholangiopancreatography (MRCP had showed a hydropic gallbladder with an excessively dilated CBD and a 110 mm × 41 mm stone. In the operation, an excessively dilated CBD was seen and after choledochotomy and a very large calculus that filled CBD completely. Choledochotomy incision was carried forward and a T-tube choledochostomy with choledochoduodenostomy (CD was performed. The patient was discharged without any complications on postoperative 8 th day. Conclusion: Benign gallstone disease is a multifactorial process, with risk factors such as obesity, hemolytic diseases, diabetes mellitus, and pregnancy. Risk factors for choledocholithiasis are similar to those for gallstone disease. MRCP is a non-invasive technique in detecting choledocholithiasis. The gold standard intervention for CBD stones is ERCP. Stones in CBD may reach very considerable dimensions without causing serious symptoms. The most common symptom is jaundice. During preoperative radiological examination, giant stones may be interfered with malignancies. Surgeons should obey conventional algorithms in diagnosis and open surgery must be kept in mind in earlier stages without being too insistent on endoscopic interventions.
Giant cell tumor of soft tissue: a case report with emphasis on MR imaging
Lee, Moon Young; Jee, Won-Hee [The Catholic University of Korea, Department of Radiology, Seoul St. Mary' s Hospital, School of Medicine, Seocho-gu, Seoul (Korea, Republic of); Jung, Chan Kwon [The Catholic University of Korea, Department of Pathology, Seoul St. Mary' s Hospital, College of Medicine, Seocho-gu, Seoul (Korea, Republic of); Yoo, Ie Ryung [The Catholic University of Korea, Department of Nuclear Medicine, Seoul St. Mary' s Hospital, College of Medicine, Seocho-gu, Seoul (Korea, Republic of); Chung, Yang-Guk [The Catholic University of Korea, Department of Orthopedic Surgery, Seoul St. Mary' s Hospital, College of Medicine, Seocho-gu, Seoul (Korea, Republic of)
2015-04-03
Giant cell tumor of soft tissue is a rare neoplasm, histologically resembling giant cell tumor of bone. In this report, we describe a deep and solid giant cell tumor of soft tissue interpreted as a benign soft tissue tumor based on magnetic resonance (MR) findings with hypointense to intermediate signals on T2-weighted images and impeded diffusivity (water movement) on diffusion-weighted imaging (DWI), which could suggest a giant-cell-containing benign soft tissue tumor, despite the malignancy suggested by {sup 18}F-fluorodeoxyglucose positron emission tomography-computed tomography in a 35-year-old male. To our knowledge, this report introduces the first deep, solid giant cell tumor of soft tissue with MR features of a giant-cell-containing benign soft tissue tumor, despite the malignancy-mimicking findings on {sup 18}F-FDG PET-CT. (orig.)
Mass loss from red giants - Results from ultraviolet spectroscopy
Linsky, J. L.
1985-01-01
New instrumentation in space, primarily the IUE spacecraft, has enabled the application of ultraviolet spectroscopic techniques to the determination of physical properties and reliable mass loss rates for red giant winds. One important result is the determination of where in the H-R diagram are found stars with hot outer atmospheres and with cool winds. So far it appears that single cool stars, except perhaps the so-called hybrid stars, have either hot outer atmospheres or cool winds but not both. The C II resonance (1335 A) and intersystem (2325 A) multiplets have been used to derive temperatures, densities, and geometrical extents for the chromospheric portions of red giant winds, with the result that the red giants and the earlier giants with hot coronae have qualitatively different chromospheres. Mass loss rates can now be derived accurately from the analysis of asymmetric emission lines, such as the Mg II resonance lines, and from P Cygni profile lines of atoms in the dominant ionization stage when a hot star is available to probe the wind of a red giant. The Zeta Aur systems, consisting of a K-M supergiant and a main sequence B star are important systems for reliable mass loss rates for the red supergiant components are becoming available.
Vipul Yagnik
2011-07-01
Full Text Available Fibroadenomas are benign solid tumor associated with aberration of normal lobular development. Juvenile giant fibroadenoma is usually single and >5 cm in size /or >500 gms in weight. Important differential diagnoses are: phyllodes tumor and juvenile gigantomastia. Simple excision is the treatment of choice.
Giant Congenital Melanocytic Nevus
Rasmussen, Bo Sonnich; Henriksen, Trine Foged; Kølle, Stig-Frederik Trojahn
2015-01-01
Giant congenital melanocytic nevi (GCMN) occur in 1:20,000 livebirths and are associated with increased risk of malignant transformation. The treatment of GCMN from 1981 to 2010 in a tertiary referral center was reviewed evaluating the modalities used, cosmetic results, associated complications...
Ollenburger, Mary H.; Descheemaeker, Katrien; Crane, Todd A.; Sanogo, Ousmane M.; Giller, Ken E.
2016-01-01
The World Bank argued that West Africa's Guinea Savannah zone forms part of “Africa's Sleeping Giant,” where increases in agricultural production could be an engine of economic growth, through expansion of cultivated land in sparsely populated areas. The district of Bougouni, in southern Mali,
Microwave plasmatrons for giant integrated circuit processing
Petrin, A.B.
2000-02-01
A method for calculating the interaction of a powerful microwave with a plane layer of magnetoactive low-pressure plasma under conditions of electron cyclotron resonance is presented. In this paper, the plasma layer is situated between a plane dielectric layer and a plane metal screen. The calculation model contains the microwave energy balance, particle balance, and electron energy balance. The equation that expressed microwave properties of nonuniform magnetoactive plasma is found. The numerical calculations of the microwave-plasma interaction for a one-dimensional model of the problem are considered. Applications of the results for microwave plasmatrons designed for processing giant integrated circuits are suggested.
Couch, Sean M.; Graziani, Carlo; Flocke, Norbert
2013-12-01
Self-gravity computation by multipole expansion is a common approach in problems such as core-collapse and Type Ia supernovae, where single large condensations of mass must be treated. The standard formulation of multipole self-gravity in arbitrary coordinate systems suffers from two significant sources of error, which we correct in the formulation presented in this article. The first source of error is due to the numerical approximation that effectively places grid cell mass at the central point of the cell, then computes the gravitational potential at that point, resulting in a convergence failure of the multipole expansion. We describe a new scheme that avoids this problem by computing gravitational potential at cell faces. The second source of error is due to sub-optimal choice of location for the expansion center, which results in angular power at high multipole l values in the gravitational field, requiring a high—and expensive—value of multipole cutoff l max. By introducing a global measure of angular power in the gravitational field, we show that the optimal coordinate for the expansion is the square-density-weighted mean location. We subject our new multipole self-gravity algorithm, implemented in the FLASH simulation framework, to two rigorous test problems: MacLaurin spheroids for which exact analytic solutions are known, and core-collapse supernovae. We show that key observables of the core-collapse simulations, particularly shock expansion, proto-neutron star motion, and momentum conservation, are extremely sensitive to the accuracy of the multipole gravity, and the accuracy of their computation is greatly improved by our reformulated solver.
Couch, Sean M; Flocke, Norbert
2013-01-01
Self-gravity computation by multipole expansion is a common approach in problems such as core-collapse and Type Ia supernovae, where single large condensations of mass must be treated. The standard formulation of multipole self-gravity suffers from two significant sources of error, which we correct in the formulation presented in this article. The first source of error is due to the numerical approximation that effectively places grid cell mass at the central point of the cell, then computes the gravitational potential at that point, resulting in a convergence failure of the multipole expansion. We describe a new scheme that avoids this problem by computing gravitational potential at cell faces. The second source of error is due to sub-optimal choice of location for the expansion center, which results in angular power at high multipole $l$ values in the gravitational field, requiring a high --- and expensive --- value of multipole cutoff \\lmax. By introducing a global measure of angular power in the gravitati...
Huang, Lei [Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, Shanghai 200030 (China); Yu, Cong, E-mail: muduri@shao.ac.cn, E-mail: cyu@ynao.ac.cn [Key Laboratory for the Structure and Evolution of Celestial Object, Chinese Academy of Sciences, Kunming 650011 (China)
2014-04-01
We propose a catastrophic eruption model for the enormous energy release of magnetars during giant flares, in which a toroidal and helically twisted flux rope is embedded within a force-free magnetosphere. The flux rope stays in stable equilibrium states initially and evolves quasi-statically. Upon the loss of equilibrium, the flux rope cannot sustain the stable equilibrium states and erupts catastrophically. During the process, the magnetic energy stored in the magnetosphere is rapidly released as the result of destabilization of global magnetic topology. The magnetospheric energy that could be accumulated is of vital importance for the outbursts of magnetars. We carefully establish the fully open fields and partially open fields for various boundary conditions at the magnetar surface and study the relevant energy thresholds. By investigating the magnetic energy accumulated at the critical catastrophic point, we find that it is possible to drive fully open eruptions for dipole-dominated background fields. Nevertheless, it is hard to generate fully open magnetic eruptions for multipolar background fields. Given the observational importance of the multipolar magnetic fields in the vicinity of the magnetar surface, it would be worthwhile to explore the possibility of the alternative eruption approach in multipolar background fields. Fortunately, we find that flux ropes may give rise to partially open eruptions in the multipolar fields, which involve only partial opening of background fields. The energy release fractions are greater for cases with central-arcaded multipoles than those with central-caved multipoles that emerged in background fields. Eruptions would fail only when the centrally caved multipoles become extremely strong.
Hoffman, Gary S
2016-11-01
This issue provides a clinical overview of giant cell arteritis, focusing on diagnosis, treatment, and practice improvement. The content of In the Clinic is drawn from the clinical information and education resources of the American College of Physicians (ACP), including MKSAP (Medical Knowledge and Self-Assessment Program). Annals of Internal Medicine editors develop In the Clinic in collaboration with the ACP's Medical Education and Publishing divisions and with the assistance of additional science writers and physician writers.
Intraoral giant condyloma acuminatum
Gupta R
2001-09-01
Full Text Available A case of intraoral giant condyloma acuminatum is reported in a 50- year- old Indian. He did not respond to topical application of podophyllin 20% but responded partially to electric cauterisation. Surgical excision was done to get rid of the warty growh completely. Since there were no skin or genital lesions and no history of marital or extramarital sexual contact the lesion was probably acquired from environmental sources. Nonsexual transmission should be considered especially when the lesions are extragenital.
Schenk C.
1992-02-01
Full Text Available We are in the second year of fieldwork surveying for Giant Otters in the southeastern rainforest of Peru, in three areas with differing levels of legal protection. While there is some illegal hunting still happening outside the protected areas, the main threat to the otters is badly-conducted tourism. Well-organised tourism can be a promising argument for establishing protected areas like national parks.
Lozano, Yolanda; Prinsloo, Andrea
2013-01-01
In this article we extend the construction of giant gravitons from holomorphic surfaces [arXiv:hep-th/0010206] to the ABJM correspondence. We construct a new class of 1/6-BPS M5-branes wrapping 5-manifolds in S^7/Z_k and supported by a large angular momentum in the orbifold space. These orbifold giant gravitons undergo a supersymmetry enhancement to 1/3-BPS and 1/2-BPS configurations in special cases. The compactification of M-theory on AdS_4 x S^7/Z_k to type IIA superstring theory on AdS_4 x CP^3 then gives rise to another new class of 1/6-BPS D4 and NS5-branes wrapping 4 and 5-manifolds in CP^3. The D4-branes carry a combination of D0-brane charge and angular momentum in the complex projective space, while the NS5-branes are supported only by D0-brane charge. Finally, we present a detailed analysis of a one-parameter family of 1/2-BPS M5-brane orbifold giant gravitons, and their D4 and NS5-brane CP^3 descendants.
Delgrange, Etienne; Raverot, Gerald; Bex, Marie
2014-01-01
OBJECTIVE: To characterise distinctive clinical features of giant prolactinomas in women. DESIGN: A multicentre, retrospective case series and literature review. METHODS: We collected data from 15 female patients with a pituitary tumour larger than 4 cm and prolactin levels above 1000 μg/l and id......OBJECTIVE: To characterise distinctive clinical features of giant prolactinomas in women. DESIGN: A multicentre, retrospective case series and literature review. METHODS: We collected data from 15 female patients with a pituitary tumour larger than 4 cm and prolactin levels above 1000 μg....../l and identified 19 similar cases from the literature; a gender-based comparison of the frequency and age distribution was obtained from a literature review. RESULTS: The initial PubMed search using the term 'giant prolactinomas' identified 125 patients (13 women) responding to the inclusion criteria. The female......:male ratio was 1:9. Another six female patients were found by extending the literature search, while our own series added 15 patients. The median age at diagnosis was 44 years in women compared with 35 years in men (Pwomen (n=34), we...
Point charges optimally placed to represent the multipole expansion of charge distributions.
Ramu Anandakrishnan
Full Text Available We propose an approach for approximating electrostatic charge distributions with a small number of point charges to optimally represent the original charge distribution. By construction, the proposed optimal point charge approximation (OPCA retains many of the useful properties of point multipole expansion, including the same far-field asymptotic behavior of the approximate potential. A general framework for numerically computing OPCA, for any given number of approximating charges, is described. We then derive a 2-charge practical point charge approximation, PPCA, which approximates the 2-charge OPCA via closed form analytical expressions, and test the PPCA on a set of charge distributions relevant to biomolecular modeling. We measure the accuracy of the new approximations as the RMS error in the electrostatic potential relative to that produced by the original charge distribution, at a distance 2x the extent of the charge distribution--the mid-field. The error for the 2-charge PPCA is found to be on average 23% smaller than that of optimally placed point dipole approximation, and comparable to that of the point quadrupole approximation. The standard deviation in RMS error for the 2-charge PPCA is 53% lower than that of the optimal point dipole approximation, and comparable to that of the point quadrupole approximation. We also calculate the 3-charge OPCA for representing the gas phase quantum mechanical charge distribution of a water molecule. The electrostatic potential calculated by the 3-charge OPCA for water, in the mid-field (2.8 Å from the oxygen atom, is on average 33.3% more accurate than the potential due to the point multipole expansion up to the octupole order. Compared to a 3 point charge approximation in which the charges are placed on the atom centers, the 3-charge OPCA is seven times more accurate, by RMS error. The maximum error at the oxygen-Na distance (2.23 Å is half that of the point multipole expansion up to the octupole
Self-Consistent Description of Multipole Strength in Exotic Nuclei I: Method
Terasaki, J; Bender, M; Dobaczewski, J; Nazarewicz, W; Stoitsov, M V
2004-01-01
We use the canonical Hartree-Fock-Bogoliubov basis to implement a completely self-consistent quasiparticle-random-phase approximation with arbitrary Skyrme energy density functionals and density-dependent pairing functionals. The point of the approach is to accurately describe multipole strength functions in spherical even-even nuclei, including weakly-bound drip-line systems. We describe the method and carefully test its accuracy, particularly in handling spurious modes. To illustrate our approach, we calculate isoscalar and isovector monopole, dipole, and quadrupole strength functions in several Sn isotopes, both in the stable region and at the drip lines.
Chremmos, Ioannis; Giamalaki, Melpomeni; Yannopapas, Vassilios; Paspalakis, Emmanuel
2014-01-01
We present a formulation for deriving effective medium properties of infinitely periodic two-dimensional metamaterial lattice structures beyond the static and quasi-static limits. We utilize the multipole expansions, where the polarization currents associated with the supported Bloch modes are expressed via the electric dipole, magnetic dipole, and electric quadrupole moments per unit length. We then propose a method to calculate the Bloch modes based on the lattice geometry and individual unit element structure. The results revert to well-known formulas in the quasistatic limit and are useful for the homogenization of nanorod-type metamaterials which are frequently used in optical applications.
Plasma confinement time in trimix-M galatea multipole magnetic trap
Bishaev, A. M.; Bugrova, A. I.; Kozintseva, M. V.; Lipatov, A. S.; Sigov, A. S.; Kharchevnikov, V. K.
2010-05-01
The confinement time of hydrogen plasma trapped in a Trimix-M magnetic multipole galatea was studied in a range of plasma densities (1 × 1016 - 6 × 1018 m-3) and ion energies (˜100-300 eV). It is established that (i) the confinement time increases with decreasing plasma density in the trap and (ii) as the barrier magnetic field is increased, the plasma confinement time grows faster than according to a linear law. The obtained results are indicative of a collisional character of plasma diffusion through the barrier field in the trap.
Adaptive grouping for the higher-order multilevel fast multipole method
Borries, Oscar Peter; Jørgensen, Erik; Meincke, Peter
2014-01-01
An alternative parameter-free adaptive approach for the grouping of the basis function patterns in the multilevel fast multipole method is presented, yielding significant memory savings compared to the traditional Octree grouping for most discretizations, particularly when using higher-order basis...... functions. Results from both a uniformly and nonuniformly meshed scatterer are presented, showing how the technique is worthwhile even for regular meshes, and demonstrating that there is no loss of accuracy in spite of the large reduction in memory requirements and the relatively low computational cost....
Application of A Fast Multipole BIEM for Flow Diffraction from A 3D Body
滕斌; 宁德志
2004-01-01
A Fast Multipole Method (FMM) is developed as a numerical approach to the reduction of the computational cost and requirement memory capacity for a large in solving large-scale problems. In this paper it is applied to the boundary integral equation method (BIEM) for current diffraction from arbitrary 3D bodies. The boundary integral equation is discretized by higher order elements, the FMM is applied to avoid the matrix/vector product, and the resulting algebraic equation is solved by the Generalized Conjugate Residual method (GCR). Numerical examination shows that the FMM is more efficient than the direct evaluation method in computational cost and storage of computers.
Kinjo, Ryota; Kagamihata, Akihiro; Seike, Takamitsu; Kishimoto, Hikaru; Ohashi, Haruhiko; Yamamoto, Shigeru; Tanaka, Takashi
2017-07-01
A lightweight-compact variable-gap undulator (LCVGU) having the force-cancellation system based on the multipole monolithic magnets (MMMs) has been developed. The LCVGU is free from the heavy mechanical frames, which is a fundamental element specific to conventional variable-gap undulators (VGUs) because of a strong attractive force, and thus the cost and time for construction and installation are expected to be significantly reduced; the MMMs counteract the strong attractive force in a cost-effective manner. Results of mechanical tests and magnetic-field measurements of two prototype LCVGUs equipped with the proposed force cancellation system have revealed the comparable performance with the conventional VGUs.
Multicentric Giant Cell Tumor of Bone: Synchronous and Metachronous Presentation
Reiner Wirbel
2013-01-01
Full Text Available A 27-year-old man treated 2.5 years ago for synchronous multicentric giant cell tumor of bone located at the right proximal humerus and the right 5th finger presented now with complaints of pain in his right hip and wrist of two-month duration. Radiology and magnetic resonance revealed multicentric giant cell tumor lesions of the right proximal femur, the left ileum, the right distal radius, and the left distal tibia. The patient has an eighteen-year history of a healed osteosarcoma of the right tibia that was treated with chemotherapy, resection, and allograft reconstruction. A literature review establishes this as the first reported case of a patient with synchronous and metachronous multicentric giant cell tumor who also has a history of osteosarcoma.
BAI Sha; P. Bambade; WANG Dou; GAO Jie; M. Woodley; M. Masuzawa
2012-01-01
The ATF2 project is the final focus system prototype for the ILC and CLIC linear collider projects,with the purpose of reaching a 37nm vertical beam size at the interaction point.In the nanometer beam size regime,higher order multipoles in magnets become a crucial point for consideration.The strength and rotation angle of the ATF2 QEA magnets were reconstructed from the IHEP measurements and compared with the KEK ones to be identical.Based on the study of the skew multipoles sensitivity,we report on the analysis of the possible mitigation of the measured multipoles.A suggestion is given which will benefit the ATF2 present commissioning to reach the goal beam size,and also the reduced β optics in future.
Giant bullae mimicking tension pneumothorax
Ahmet Erbey
2012-12-01
Full Text Available Giant bullae may mimic tension pneumothorax radiologicallyso that it may expand completely to hemithorax,increase of radiolucency mediastinal shift, flattening ofdiaphragm and printing on trachea. Sixty one year oldmale patient with giant bullae misdiagnosed as tensionpneumothorax and underwent to tube thoracostomy. Thedifferential diagnosis of giant bullae and tension pneumothoraxmay be confusing. The therapeutic approaches ofthese two radiologically similar entities differ significantly.Thus proper physical assessment and radiological examinationis crucial in the differential diagnosis and computedtomography examination should be performed before theadjustment of therapy. J Clin Exp Invest 2012; 3(4: 548-551Key words: Tension pneumothorax, giant bullae, computedtomography, tube thoracostomy
Superdimensional Metamaterial Resonators
Greenleaf, Allan; Kurylev, Yaroslav; Lassas, Matti; Uhlmann, Gunther
2014-01-01
We propose a fundamentally new method for the design of metamaterial arrays, valid for any waves modeled by the Helmholtz equation, including scalar optics and acoustics. The design and analysis of these devices is based on eigenvalue and eigenfunction asymptotics of solutions to Schr\\"odinger wave equations with harmonic and degenerate potentials. These resonators behave superdimensionally, with a higher local density of eigenvalues and greater concentration of waves than expected from the physical dimension, e.g., planar resonators function as 3- or higher-dimensional media, and bulk material as effectively of dimension 4 or higher. Applications include antennas with a high density of resonant frequencies and giant focussing, and are potentially broadband.
A genetic algorithm for optimizing multi-pole Debye models of tissue dielectric properties
Clegg, J.; Robinson, M. P.
2012-10-01
Models of tissue dielectric properties (permittivity and conductivity) enable the interactions of tissues and electromagnetic fields to be simulated, which has many useful applications in microwave imaging, radio propagation, and non-ionizing radiation dosimetry. Parametric formulae are available, based on a multi-pole model of tissue dispersions, but although they give the dielectric properties over a wide frequency range, they do not convert easily to the time domain. An alternative is the multi-pole Debye model which works well in both time and frequency domains. Genetic algorithms are an evolutionary approach to optimization, and we found that this technique was effective at finding the best values of the multi-Debye parameters. Our genetic algorithm optimized these parameters to fit to either a Cole-Cole model or to measured data, and worked well over wide or narrow frequency ranges. Over 10 Hz-10 GHz the best fits for muscle, fat or bone were each found for ten dispersions or poles in the multi-Debye model. The genetic algorithm is a fast and effective method of developing tissue models that compares favourably with alternatives such as the rational polynomial fit.
Szmytkowski, Radosław; Łukasik, Grzegorz
2016-09-01
We present tabulated data for several families of static electric and magnetic multipole susceptibilities for hydrogenic atoms with nuclear charge numbers from the range 1 ⩽ Z ⩽ 137. Atomic nuclei are assumed to be point-like and spinless. The susceptibilities considered include the multipole electric polarizabilities α E L → E L and magnetizabilities (magnetic susceptibilities) χ M L → M L with 1 ⩽ L ⩽ 4 (i.e., the dipole, quadrupole, octupole and hexadecapole ones), the electric-to-magnetic cross-susceptibilities α E L → M(L - 1) with 2 ⩽ L ⩽ 5 and α E L → M(L + 1) with 1 ⩽ L ⩽ 4, the magnetic-to-electric cross-susceptibilities χ M L → E(L - 1) with 2 ⩽ L ⩽ 5 and χ M L → E(L + 1) with 1 ⩽ L ⩽ 4 (it holds that χ M L → E(L ∓ 1) =α E(L ∓ 1) → M L), and the electric-to-toroidal-magnetic cross-susceptibilities α E L → T L with 1 ⩽ L ⩽ 4. Numerical values are computed from general exact analytical formulas, derived by us elsewhere within the framework of the Dirac relativistic quantum mechanics, and involving generalized hypergeometric functions 3F2 of the unit argument.
Multipole Theory in Electromagnetism: Classical, Quantum and Symmetry Aspects, with Applications
Sihvola, Ari [Helsinki University of Technology (Finland)
2005-03-11
'Good reasons must, of force, give place to better', observes Brutus to Cassius, according to William Shakespeare in Julius Caesar. Roger Raab and Owen de Lange seem to agree, as they cite this sentence in the concluding chapter of their new book on the importance of exact multipole analysis in macroscopic electromagnetics. Very true and essential to remember in our daily research work. The two scientists from the University of Natal in Pietermaritzburg, South Africa (presently University of KwaZulu-Natal) have been working for a very long time on the accurate description of electric and magnetic response of matter and have published much of their findings in various physics journals. The present book gives us a clear and coherent exposition of many of these results. The important message of Raab and de Lange is that in the macroscopic description of matter, a correct balance between the various orders of electric and magnetic multipole terms has to be respected. If the inclusion of magnetic dipole terms is not complemented with electric quadrupoles, there is a risk of losing the translational invariance of certain important quantities. This means that the values of these quantities depend on the choice of the origin{exclamation_point} 'It can't be Nature, for it is not sense' is another of the apt literary citations in the book. Often monographs written by researchers look like they have been produced using a cut-and-paste technique; earlier published articles are included in the same book but, unfortunately, too little additional effort is expended into moulding the totality into a unified story. This is not the case with Raab and de Lange. The structure and the text flow of the book serve perfectly its important message. After the obligatory introduction of material response to electromagnetic fields, constitutive relations, basic quantum theory and spacetime properties, a chapter follows with transmission and scattering effects where
Multipole and field uniformity tailoring of a 750 MHz rf dipole
Delayen, Jean R. [JLAB, Old Dominion University; Castillo, Alejandro [JLAB, Old Dominion University
2014-12-01
In recent years great interest has been shown in developing rf structures for beam separation, correction of geometrical degradation on luminosity, and diagnostic applications in both lepton and hadron machines. The rf dipole being a very promising one among all of them. The rf dipole has been tested and proven to have attractive properties that include high shunt impedance, low and balance surface fields, absence of lower order modes and far-spaced higher order modes that simplify their damping scheme. As well as to be a compact and versatile design in a considerable range of frequencies, its fairly simple geometry dependency is suitable both for fabrication and surface treatment. The rf dipole geometry can also be optimized for lowering multipacting risk and multipole tailoring to meet machine specific field uniformity tolerances. In the present work a survey of field uniformities, and multipole contents for a set of 750 MHz rf dipole designs is presented as both a qualitative and quantitative analysis of the inherent flexibility of the structure and its limitations.
A genetic algorithm for optimizing multi-pole Debye models of tissue dielectric properties.
Clegg, J; Robinson, M P
2012-10-01
Models of tissue dielectric properties (permittivity and conductivity) enable the interactions of tissues and electromagnetic fields to be simulated, which has many useful applications in microwave imaging, radio propagation, and non-ionizing radiation dosimetry. Parametric formulae are available, based on a multi-pole model of tissue dispersions, but although they give the dielectric properties over a wide frequency range, they do not convert easily to the time domain. An alternative is the multi-pole Debye model which works well in both time and frequency domains. Genetic algorithms are an evolutionary approach to optimization, and we found that this technique was effective at finding the best values of the multi-Debye parameters. Our genetic algorithm optimized these parameters to fit to either a Cole-Cole model or to measured data, and worked well over wide or narrow frequency ranges. Over 10 Hz-10 GHz the best fits for muscle, fat or bone were each found for ten dispersions or poles in the multi-Debye model. The genetic algorithm is a fast and effective method of developing tissue models that compares favourably with alternatives such as the rational polynomial fit.
Sihvola, Ari
2005-03-01
`Good reasons must, of force, give place to better', observes Brutus to Cassius, according to William Shakespeare in Julius Caesar. Roger Raab and Owen de Lange seem to agree, as they cite this sentence in the concluding chapter of their new book on the importance of exact multipole analysis in macroscopic electromagnetics. Very true and essential to remember in our daily research work. The two scientists from the University of Natal in Pietermaritzburg, South Africa (presently University of KwaZulu-Natal) have been working for a very long time on the accurate description of electric and magnetic response of matter and have published much of their findings in various physics journals. The present book gives us a clear and coherent exposition of many of these results. The important message of Raab and de Lange is that in the macroscopic description of matter, a correct balance between the various orders of electric and magnetic multipole terms has to be respected. If the inclusion of magnetic dipole terms is not complemented with electric quadrupoles, there is a risk of losing the translational invariance of certain important quantities. This means that the values of these quantities depend on the choice of the origin! `It canÂ't be Nature, for it is not sense' is another of the apt literary citations in the book. Often monographs written by researchers look like they have been produced using a cut-and-paste technique; earlier published articles are included in the same book but, unfortunately, too little additional effort is expended into moulding the totality into a unified story. This is not the case with Raab and de Lange. The structure and the text flow of the book serve perfectly its important message. After the obligatory introduction of material response to electromagnetic fields, constitutive relations, basic quantum theory and spacetime properties, a chapter follows with transmission and scattering effects where everything seems to work well with the `old
Pyzer-Knapp, Edward O.; Thompson, Hugh P. G.; Day, Graeme M.
2016-01-01
We present a re-parameterization of a popular intermolecular force field for describing intermolecular interactions in the organic solid state. Specifically we optimize the performance of the exp-6 force field when used in conjunction with atomic multipole electrostatics. We also parameterize force fields that are optimized for use with multipoles derived from polarized molecular electron densities, to account for induction effects in molecular crystals. Parameterization is performed against a set of 186 experimentally determined, low-temperature crystal structures and 53 measured sublimation enthalpies of hydrogen-bonding organic molecules. The resulting force fields are tested on a validation set of 129 crystal structures and show improved reproduction of the structures and lattice energies of a range of organic molecular crystals compared with the original force field with atomic partial charge electrostatics. Unit-cell dimensions of the validation set are typically reproduced to within 3% with the re-parameterized force fields. Lattice energies, which were all included during parameterization, are systematically underestimated when compared with measured sublimation enthalpies, with mean absolute errors of between 7.4 and 9.0%. PMID:27484370
Orientation measurement based on magnetic inductance by the extended distributed multi-pole model.
Wu, Fang; Moon, Seung Ki; Son, Hungsun
2014-06-27
This paper presents a novel method to calculate magnetic inductance with a fast-computing magnetic field model referred to as the extended distributed multi-pole (eDMP) model. The concept of mutual inductance has been widely applied for position/orientation tracking systems and applications, yet it is still challenging due to the high demands in robust modeling and efficient computation in real-time applications. Recently, numerical methods have been utilized in design and analysis of magnetic fields, but this often requires heavy computation and its accuracy relies on geometric modeling and meshing that limit its usage. On the other hand, an analytical method provides simple and fast-computing solutions but is also flawed due to its difficulties in handling realistic and complex geometries such as complicated designs and boundary conditions, etc. In this paper, the extended distributed multi-pole model (eDMP) is developed to characterize a time-varying magnetic field based on an existing DMP model analyzing static magnetic fields. The method has been further exploited to compute the mutual inductance between coils at arbitrary locations and orientations. Simulation and experimental results of various configurations of the coils are presented. Comparison with the previously published data shows not only good performance in accuracy, but also effectiveness in computation.
Fast multipole boundary element analysis of 2D viscoelastic composites with imperfect interfaces
无
2010-01-01
A fast multipole boundary element method(FMBEM)is developed for the analysis of 2D linear viscoelastic composites with imperfect viscoelastic interfaces.The transformed fast multipole formulations are established using the time domain method. To simulate the viscoelastic behavior of imperfect interfaces that are frequently encountered in practice,the Kelvin type model is introduced.The FMBEM is further improved by incorporating naturally the interaction among inclusions as well as eliminating the phenomenon of material penetration.Since all the integrals are evaluated analytically,high accuracy and fast convergence of the numerical scheme are obtained.Several numerical examples,including planar viscoelastic composites with a single inclusion or randomly distributed multi-inclusions are presented.The numerical results are compared with the developed analytical solutions,which illustrates that the proposed FMBEM is very efficient in determining the macroscopic viscoelastic behavior of the particle-reinforced composites with the presence of imperfect interfaces.The laboratory measurements of the mixture creep compliance of asphalt concrete are also compared with the prediction by the developed model.
Exchange splitting of the interaction energy and the multipole expansion of the wave function
Gniewek, Piotr
2015-01-01
The exchange splitting $J$ of the interaction energy of the hydrogen atom with a proton is calculated using the conventional surface-integral formula $J_{\\textrm{surf}}[\\varphi]$, the volume-integral formula of the symmetry-adapted perturbation theory $J_{\\textrm{SAPT}}[\\varphi]$, and a variational volume-integral formula $J_{\\textrm{var}}[\\varphi]$. The calculations are based on the multipole expansion of the wave function $\\varphi$, which is divergent for any internuclear distance $R$. Nevertheless, the resulting approximations to the leading coefficient $j_0$ in the large-$R$ asymptotic series $J(R) = 2 e^{-R-1} R ( j_0 + j_1 R^{-1} + j_2 R^{-2} +\\cdots ) $ converge, with the rate corresponding to the convergence radii equal to 4, 2, and 1 when the $J_{\\textrm{var}}[\\varphi]$, $J_{\\textrm{surf}}[\\varphi]$, and $J_{\\textrm{SAPT}}[\\varphi]$ formulas are used, respectively. Additionally, we observe that also the higher $j_k$ coefficients are predicted correctly when the multipole expansion is used in the $J_{...
Lu, Benzhuo; Cheng, Xiaolin; Huang, Jingfang; McCammon, J. Andrew
2013-11-01
A Fortran program package is introduced for rapid evaluation of the electrostatic potentials and forces in biomolecular systems modeled by the linearized Poisson-Boltzmann equation. The numerical solver utilizes a well-conditioned boundary integral equation (BIE) formulation, a node-patch discretization scheme, a Krylov subspace iterative solver package with reverse communication protocols, and an adaptive new version of the fast multipole method in which the exponential expansions are used to diagonalize the multipole-to-local translations. The program and its full description, as well as several closely related libraries and utility tools are available at http://lsec.cc.ac.cn/~lubz/afmpb.html and a mirror site at http://mccammon.ucsd.edu/. This paper is a brief summary of the program: the algorithms, the implementation and the usage. Restrictions: Only three or six significant digits options are provided in this version. Unusual features: Most of the codes are in Fortran77 style. Memory allocation functions from Fortran90 and above are used in a few subroutines. Additional comments: The current version of the codes is designed and written for single core/processor desktop machines. Check http://lsec.cc.ac.cn/lubz/afmpb.html for updates and changes. Running time: The running time varies with the number of discretized elements (N) in the system and their distributions. In most cases, it scales linearly as a function of N.
A Fast Multipole Algorithm with Virtual Cube Partitioning for 3-D Capacitance Extraction
YANGZhaozhi; WANGZeyi
2004-01-01
In this paper a fast indirect boundaryelement method based on the multipole algorithm for capacitance extraction of three-dimensional (3-D) geometries, virtual cube multipole algorithm, is described. First,each 2-D boundary element is regarded as a set of particles with charge rather than a single particle, so the relations between the positions of elements themselves are considered instead of the relations between the center-points of the elements, and a new strategy for cube partitioning is introduced. This strategy overcomes the inadequacy of the methods that associating panels to particles, does not need to break up every panel contained in more than one cube, and has higher speed and precision. Next, a new method is proposed to accelerate the potential integration between the panels that are near to each other. Making good use of the similarity in the 2-D boundary integration,the fast potential integral approach decreases the burden of direct potential computing. Experiments confirm that the algorithm is accurate and has nearly linear computational growth as O(nm), where n is the number of panels and rn is the number of conductors. The new algorithm is implemented and the performance is compared with previous algorithms, such as Fastcap2 of MIT, for k×k bus examples.
Local geometry of electromagnetic fields and its role in molecular multipole transitions.
Yang, Nan; Cohen, Adam E
2011-05-12
Electromagnetic fields with complex spatial variation routinely arise in Nature. We study the response of a small molecule to monochromatic fields of arbitrary three-dimensional geometry. First, we consider the allowed configurations of the fields and field gradients at a single point in space. Many configurations cannot be generated from a single plane wave, regardless of polarization, but any allowed configuration can be generated by superposition of multiple plane waves. There is no local configuration of the fields and gradients that requires near-field effects. Second, we derive a set of local electromagnetic quantities, each of which couples to a particular multipole transition. These quantities are small or zero in plane waves, but can be large in regions of certain superpositions of plane waves. Our findings provide a systematic framework for designing far-field and near-field experiments to drive multipole transitions. The proposed experiments provide information on molecular structure that is inaccessible to other spectroscopic techniques and open the possibility for new types of optical control of molecules.
Werner, Hans-Joachim
2016-11-01
The accuracy of multipole approximations for distant pair energies in local second-order Møller-Plesset perturbation theory (LMP2) as introduced by Hetzer et al. [Chem. Phys. Lett. 290, 143 (1998)] is investigated for three chemical reactions involving molecules with up to 92 atoms. Various iterative and non-iterative approaches are compared, using different energy thresholds for distant pair selection. It is demonstrated that the simple non-iterative dipole-dipole approximation, which has been used in several recent pair natural orbitals (PNO)-LMP2 and PNO-LCCSD (local coupled-cluster with singles and doubles) methods, may underestimate the distant pair energies by up to 50% and can lead to significant errors in relative energies, unless very tight thresholds are used. The accuracy can be much improved by including higher multipole orders and by optimizing the distant pair amplitudes iteratively along with all other amplitudes. A new approach is presented in which very small special PNO domains for distant pairs are used in the iterative approach. This reduces the number of distant pair amplitudes by 3 orders of magnitude and keeps the additional computational effort for the iterative optimization of distant pair amplitudes minimal.
Imaging Extrasolar Giant Planets
Bowler, Brendan P.
2016-10-01
High-contrast adaptive optics (AO) imaging is a powerful technique to probe the architectures of planetary systems from the outside-in and survey the atmospheres of self-luminous giant planets. Direct imaging has rapidly matured over the past decade and especially the last few years with the advent of high-order AO systems, dedicated planet-finding instruments with specialized coronagraphs, and innovative observing and post-processing strategies to suppress speckle noise. This review summarizes recent progress in high-contrast imaging with particular emphasis on observational results, discoveries near and below the deuterium-burning limit, and a practical overview of large-scale surveys and dedicated instruments. I conclude with a statistical meta-analysis of deep imaging surveys in the literature. Based on observations of 384 unique and single young (≈5-300 Myr) stars spanning stellar masses between 0.1 and 3.0 M ⊙, the overall occurrence rate of 5-13 M Jup companions at orbital distances of 30-300 au is {0.6}-0.5+0.7 % assuming hot-start evolutionary models. The most massive giant planets regularly accessible to direct imaging are about as rare as hot Jupiters are around Sun-like stars. Dividing this sample into individual stellar mass bins does not reveal any statistically significant trend in planet frequency with host mass: giant planets are found around {2.8}-2.3+3.7 % of BA stars, planets spanning a broad range of masses and ages.
GIANT PROSTHETIC VALVE THROMBUS
Prashanth Kumar
2015-04-01
Full Text Available Mechanical prosthetic valves are predisposed to bleeding, thrombosis & thromboembolic complications. Overall incidence of thromboembolic complications is 1% per year who are on oral anticoagulants, whereas bleeding complications incidence is 0.5% to 6.6% per year. 1, 2 Minimization of Scylla of thromboembolic & Charybdis of bleeding complication needs a balancing act of optimal antithrombotic therapy. We are reporting a case of middle aged male patient with prosthetic mitral valve presenting in heart failure. Patient had discontinued anticoagulants, as he had subdural hematoma in the past. He presented to our institute with a giant prosthetic valve thrombus.
Sigdel, G; Agarwal, A; Keshaw, B W
2014-01-01
Urethral calculi are rare forms of urolithiasis. Majority of the calculi are migratory from urinary bladder or upper urinary tract. Primary urethral calculi usually occur in presence of urethral stricture or diverticulum. In this article we report a case of a giant posterior urethral calculus measuring 7x3x2 cm in a 47 years old male. Patient presented with acute retention of urine which was preceded by burning micturition and dribbling of urine for one week. The calculus was pushed in to the bladder through the cystoscope and was removed by suprapubic cystolithotomy.
Giant infantile pulmonary hemangioma
Pandya, Rajul; Tummala, Venkat [Hurley Medical Center One Hurley Plaza, Department of Radiology, Flint, MI (United States)
2010-12-15
We present a very unusual case of giant infantile pulmonary hemangioma presenting as a large solitary pulmonary mass. This was successfully managed with surgical resection. Histological examination revealed that the mass was positive for GLUT-1 receptor, a marker for infantile hemangioma. To our knowledge only a few cases of pulmonary hemangioma have been described previously in the literature. Pulmonary hemangiomas are very rare lesions, most of them presenting as a pulmonary mass. This case emphasizes the fact that this rare lesion should be considered in the differential of an enhancing pulmonary mass in an infant. (orig.)
Multiple giant congenital melanocytic nevi with central nervous system melanosis: A case report
Ahuja S
2003-10-01
Full Text Available A case of multiple giant congenital melanocytic naevi in whom central nervous system melanosis was detected at 6 weeks of age is described. The infant was asymptomatic, but presence of risk factors such as multiple naevi, giant naevi and naevi on scalp and posterior axial location prompted a magnetic resonance imaging study of the brain. To our knowledge, neurocutaneous melanosis at such a young age has not been reported in Indian literature.
Giant Pandas and Their Conservation
GarethDavey
2004-01-01
IT is paradoxical that themost well-known conservation symbol in the world,the giant panda, is a criti-cally endangered species.The estimated 1,600 thatremain live in the high-altitude for-ests of southwest China (within theprovinces of Sichuan, Gansu andShaanxi). Giant pandas are popularand elicit affection and admiration
Famine Threatens the Giant Panda
无
2005-01-01
Large swathes of arrow bamboo groves at and above 2,700 meters in the Piankou Nature Reserve in Sichuan's Mianyang are producing purple blooms, and some groves have started to wither and die. An absence of bamboo means famine for giant pandas living there. Sichuan has consequently activated its giant panda contingency plan.
Pysmenetska, Inna
2009-07-22
The present thesis consists of two parts. In the first part a novel experimental method for the measurement of the proton root-mean-square radius at the S-DALINAC is presented. A setup based on semiconductor detectors is realized. In contrast to previous experiments it allows a simultaneous measurement of the momentum transfer dependence of the elastic electron scattering cross section. A possible suppression of the significant electron and bremsstrahlung background observed in a test experiment was investigated with the help of different methods, such as {delta}E-E telescopes, the time of flight method with a pulsed beam and pulse shape discrimination. The combination of these methods allows a reduction of the background at all scattering angles, which should allow a successful measurement. The response of the detector system was studied with the help of Monte-Carlo simulations with an emphasis on the dependence of the expected accuracy of different parameters. The second part of this work describes an investigation of the fine structure of giant resonances in {sup 28}Si, {sup 48}Ca and {sup 166}Er with the help of a wavelet analysis. The discrete wavelet transform was used for a background determination in spectra of the iso vector E1 and the M2 giant resonances in {sup 48}Ca. This allows the extraction of 1{sup -} und 2{sup -} level densities in the excitation energy region of the respective resonances with the help of a fluctuation analysis. A fluctuation analysis of the fine structure of the isoscalar E2 resonance in {sup 166}Er allows the extraction of the coherent widths of the 2{sup +} states. In the excitation energy region E{sub x}=10-16 MeV widths between 30 and 80 eV are found. The fine structure of the giant resonances is furthermore specified by characteristic scales. In this thesis scales in {sup 28}Si and {sup 48}Ca are extracted with the help of the above mentioned wavelet transform. In {sup 28}Si the isovector E1 and isoscalar E2 resonances were
Neutral Pion Electroproduction in the Δ Resonance Region
Villano, Anthony [Rensselaer Polytechnic Inst., Troy, NY (United States)
2007-11-01
The electroproduction of baryon resonances at high Q^{2} is examined. Analysis focuses on the Δ(1232) resonance via exclusive pseudoscalar meson production of π^{0} particles. Differential cross sections are extracted for exclusive π^{0} electroproduction. In the central invariant mass (W) region the cross sections are used to extract resonant multipole amplitudes. In particular, the ratio of the electric quadrupole to magnetic dipole amplitudes (E2/M1) will be discussed for the Δ(1232) resonance. The transition to pQCD is discussed in terms of E2/M1 and other multipoles. The helicity amplitude A_{3/2} can be used as a baryon helicity conservation meter in this context and will be discussed. The fast shrinking of the resonant contribution in the Δ region is observed at this high momentum transfer. Apart from the observables related to pQCD scaling, the transition form factor G$*\\atop{M}$ is extracted along with the scalar to magnetic dipole ratio C2/M1.
Giant Intradiverticular Bladder Tumor
Noh, Mohamad Syafeeq Faeez Md; Aziz, Ahmad Fuad Abdul; Ghani, Khairul Asri Mohd; Siang, Christopher Lee Kheng; Yunus, Rosna; Yusof, Mubarak Mohd
2017-01-01
Patient: Male, 74 Final Diagnosis: Giant intradiverticular bladder tumor with metastasis Symptoms: Hematuria Medication:— Clinical Procedure: — Specialty: Urology Objective: Rare disease Background: Intradiverticular bladder tumors are rare. This renders diagnosis of an intradiverticular bladder tumor difficult. Imaging plays a vital role in achieving the diagnosis, and subsequently staging of the disease. Case Report: A 74-year-old male presented to our center with a few months history of constitutional symptoms. Upon further history, he reported hematuria two months prior to presentation, which stopped temporarily, only to recur a few days prior to coming to the hospital. The patient admitted to having lower urinary tract symptoms. However, there was no dysuria, no sandy urine, and no fever. Palpation of his abdomen revealed a vague mass at the suprapubic region, which was non tender. In view of his history and the clinical examination findings, an ultrasound of the abdomen and computed tomography (CT) was arranged. These investigations revealed a giant tumor that seemed to be arising from a bladder diverticulum, with a mass effect and hydronephrosis. He later underwent operative intervention. Conclusions: Intradiverticular bladder tumors may present a challenge to the treating physician in an atypical presentation; thus requiring a high index of suspicion and knowledge of tumor pathophysiology. As illustrated in our case, CT with its wide availability and multiplanar imaging capabilities offers a useful means for diagnosis, disease staging, operative planning, and follow-up. PMID:28246375
Rapidly Evolving Giant Dermatofibroma
K. J. Lang
2010-01-01
Full Text Available Dermatofibroma, also known as “fibrous histiocytoma”, is a benign dermal or subcutaneous poorly circumscribed proliferation of spindle-shaped fibroblasts and macrophages in the dermis. Although it is commonly present as a brownish nodule the legs of females, it may also arise on the upper extremities, trunk, and rarely on the head. The exact pathogenesis is unclear. However, it is widely believed that the originating insult to the dermis is a folliculitis, an arthropod bite, or an unspecified initial inflammatory condition. Giant dermatofibromas of greater than 5 cm in diameter are rare, with only 22 cases reported in the literature. We present a case of a rapidly evolving pedunculated mass in the groin of a male patient. Histological examination confirmed this to be a giant dermatofibroma. Though this specimen cannot is not confirmed as such, the cellular subtype is sometimes present as a larger lesion with anecdotal reports of local recurrence and distant metastases. The clinical and radiological features which were somewhat suspicious of malignancy are considered in the context of the definitive pathological diagnosis of a benign lesion.
A Case of Giant Uterine Lipoleiomyoma Simulating Malignancy
Erbil Karaman; Numan Çim; Gülay Bulut; Gülhan Elçi; Esra Andıç; Mustafa Tekin; Ali Kolusarı
2015-01-01
Introduction. Uterine leiomyoma is the most common benign pathology in women and lipoleiomyoma is an extremely rare and specific type of leiomyoma. Here, we report an unusual case of giant pedunculated subserous lipoleiomyoma misdiagnosed preoperatively as leiomyosarcoma. Case. A 45-year-old woman admitted to our gynecology outpatient clinic for complaints of abdominal distention, tiredness, and pelvic pain for the last 6 months. Sonography and abdominal magnetic resonance imaging (MRI) showe...
Kohler, Susanna
2017-01-01
Two new, large gas-giant exoplanets have been discovered orbiting close to their host stars. A recent study examining these planets and others like them may help us to better understand what happens to close-in hot Jupiters as their host stars reach the end of their main-sequence lives.OversizedGiantsUnbinned transit light curves for HAT-P-65b. [Adapted from Hartman et al. 2016]The discovery of HAT-P-65b and HAT-P-66b, two new transiting hot Jupiters, is intriguing. These planets have periods of just under 3 days and masses of roughly 0.5 and 0.8 times that of Jupiter, but their sizes are whats really interesting: they have inflated radii of 1.89 and 1.59 times that of Jupiter.These two planets, discovered using the Hungarian-made Automated Telescope Network (HATNet) in Arizona and Hawaii, mark the latest in an ever-growing sample of gas-giant exoplanets with radii larger than expected based on theoretical planetary structure models.What causes this discrepancy? Did the planets just fail to contract to the expected size when they were initially formed, or were they reinflated later in their lifetimes? If the latter, how? These are questions that scientists are only now starting to be able to address using statistics of the sample of close-in, transiting planets.Unbinned transit light curves for HAT-P-66b. [Hartman et al. 2016]Exploring Other PlanetsLed by Joel Hartman (Princeton University), the team that discovered HAT-P-65b and HAT-P-66b has examined these planets observed parameters and those of dozens of other known close-in, transiting exoplanets discovered with a variety of transiting exoplanet missions: HAT, WASP, Kepler, TrES, and KELT. Hartman and collaborators used this sample to draw conclusions about what causes some of these planets to have such large radii.The team found that there is a statistically significant correlation between the radii of close-in giant planets and the fractional ages of their host stars (i.e., the stars age divided by its full
Jansen, Thomas L. C.
2014-01-01
The effect of solvent polarizability and multipole effects on the amide I vibrational spectra of a peptide unit is investigated. Four molecular dynamics force fields of increasing complexity for the solvent are used to model both the linear absorption and two-dimensional infrared spectra. It is obse
Design and fabrication of a low frequency giant magnetostrictive transducer
Dhilsha, K.R. [Nat. Inst. of Ocean Technol, Madras (India); Markandeyulu, G.; Subrahmanyeswara Rao, B.V.P.; Rama Rao, K.V.S. [Magnetism and Magnetic Materials Laboratory, Department of Physics, Indian Institute of Technology, Madras 600 036 (India)
1997-08-01
A Tonpilz-type single ended transducer employing two rods of giant magnetostrictive materials has been fabricated and its underwater acoustic characteristics have been studied. The transducer resonated at a frequency of 3.1 kHz in air and at 2.65 kHz in water with a Q factor of 6. The TCR and RS at resonance in water have been measured to be 172.1 dB re 1 {mu}Pa/A at 1 m and -196.7 dB re 1 V/{mu}Pa respectively. The dimensions of the transducer are 60 mm in diameter and 110 mm long. (orig.)
Frederico Castelo Moura; Allan Christian Pieroni Gonçalves; Mário Luiz Ribeiro Monteiro
2006-01-01
Giant pituitary adenomas are uncommonly large tumors, greater than 4 cm in size that can produces endocrine symptoms, visual loss and cranial nerve palsies. We report the rare occurrence of seesaw nystagmus as the presenting sign of giant pituitary adenoma. A 50-year-old man presented with headache associated with visual loss and seesaw nystagmus. Perimetry revealed bitemporal hemianopia and magnetic resonance imaging showed a giant pituitary adenoma. After surgery, nystagmus disappeared. Our...
[Giant esophageal fibrovascular polyp].
Palacios, Fernando; Contardo, Carlos; Guevara, Jorge; Vera, Augusto; Aguilar, Luis; Huamán, Manuel; Palomino, Américo; Yabar, Alejandro
2003-01-01
Fibrovascular polyps are extremely rare benign neoplasias of the esophagus, which usually originate in the lower cricoid area. They do not produce any discomfort in the patient for a long time, however it may make itself evident by the patient's regurgitation of the polyp, producing asphyxia or, more frequently, dysphagia. The case of a 58 year old male patient is presented herein, with a 9 month record of dysphagia, weight loss and intermittent melena. The barium x-ray showed a distended esophagus, with a tumor running from the upper esophageal sphincter to the cardia. The endoscopy confirmed the presence of a pediculated tumor, implanted in the cervical esophagus. Surgeons suspected the potential malignancy of the tumor and performed a transhiatal esophagectomy. The final pathologic diagnosis was giant fibrovascular esophageal polyp.
Analysis and Design of Backing Beam for Multipole Wiggler (MPW14) at PLS
Lee, Hong-Gi; Jung, Young-Gyu; Park, Ki-Hyeon; Sik Han, Hong; Suck Suh, Hyung; Wha Chung, Chin; Woo Lee, Wol
2005-01-01
Pohang Accelerator Laboratory (PAL) had developed and installed a Multipole Wiggler (MPW14) to utilize high energy synchrotron radiation at Pohang Light Source (PLS). The MPW14 is a hybrid type device with period of 14 cm, minimum gap of 14 mm, maximum flux density of 2.02 Tesla and total magnetic structure length of 2056 mm. The support locations and structure of an insertion device are optimized to achieve a minimum deflection due to the magnetic loads. A Finite Element Analysis (FEA) is performed to find out the amount of maximum deflection and optimal support positions on the backing beam, the support and drive structures of the MPW14 under expected magnetic load of 14 tons. To reduce the deflection effect further, two springs are designed and installed to compensate the gap dependent magnetic loads. The optimized deflection is estimated to be about 20.6 ? while the deflection before optimization is 238 ?.
Pillet, S; Souhassou, M; Lecomte, C; Schwarz, K; Blaha, P; Rérat, M; Lichanot, A; Roversi, P
2001-05-01
This electron-density study on corundum (alpha-Al2O3) is part of the Multipole Refinement Project supported by the IUCr Commission on Charge, Spin and Momentum Densities. For this purpose, eight different data sets (two experimental and six theoretical) were chosen from which the electron density was derived by multipolar refinement (using the MOLLY program). The two experimental data sets were collected on a conventional CAD4 and at ESRF, ID11 with a CCD detector, respectively. The theoretical data sets consist of static, dynamic, static noisy and dynamic noisy moduli of structure factors calculated at the Hartree-Fock (HF) and density functional theory (DFT) levels. Comparisons of deformation and residual densities show that the multipolar analysis works satisfactorily but also indicate some drawbacks in the refinement. Some solutions and improvements during the refinements are proposed like contraction or expansion of the inner atomic shells or increasing the order of the spherical harmonic expansion.
Role of multipole moments in electric-field-induced order of dense molecular systems.
Acebal, Pablo; Carretero, Luis; Blaya, Salvador
2010-07-12
A new model is developed to describe the orientational order of dense molecular systems under an applied external electric field as a function of the n-particle distribution functions of a system under no external perturbation. From an approximation of this expression, the effects of several variables on this orientational order, such as the microscopic properties of the oriented molecules (the molecular geometry and multipole moments) and the solvent or matrix properties, are studied. The theoretical predictions show that, for a correct description of the orientational order, quadrupole and octupole moments must be included, as they play an important role in the orientational order achieved, depending on the molecular geometry. Furthermore, to verify the validity of the model, theoretical predictions are compared with experimental results, and show a good concordance.
Periodic boundary conditions and the error-controlled fast multipole method
Kabadshow, Ivo
2012-08-22
The simulation of pairwise interactions in huge particle ensembles is a vital issue in scientific research. Especially the calculation of long-range interactions poses limitations to the system size, since these interactions scale quadratically with the number of particles. Fast summation techniques like the Fast Multipole Method (FMM) can help to reduce the complexity to O(N). This work extends the possible range of applications of the FMM to periodic systems in one, two and three dimensions with one unique approach. Together with a tight error control, this contribution enables the simulation of periodic particle systems for different applications without the need to know and tune the FMM specific parameters. The implemented error control scheme automatically optimizes the parameters to obtain an approximation for the minimal runtime for a given energy error bound.
The Fast Multipole Method and Point Dipole Moment Polarizable Force Fields
Coles, Jonathan P
2014-01-01
We present a momentum conserving implementation of the fast multipole method for computing coulombic electrostatic and polarization forces from polarizable force-fields based on induced point dipole moments. We demonstrate the expected $O(N)$ scaling of that approach by performing single energy point calculations on hexamer protein subunits of the mature HIV-1 capsid. We also show the long time energy conservation in molecular dynamics at the nanosecond scale by performing simulations of a protein complex embedded in a coarse-grained solvent using both a standard integrator and a multiple time step one. Our tests show the applicability of FMM combined with state-of-the-art chemical models in molecular dynamical systems.
Efficient analysis of dielectric radomes using multilevel fast multipole algorithm with CRWG basis
无
2008-01-01
A full-wave analysis of the electromagnetic problem of a three-dimensional (3-D) antenna radiating through a 3-D dielectric radome is preserued.The problem is formulated using the Poggio-Miller-Chang-Harrington-Wu(PMCHW) approach for homogeneous dielectric objects and the electric field integral equation for conducting objects.The integral equations are discretized by the method of moment (MoM),in which the conducting and dielectric surface/interfaces are represented by curvilinear triangular patches and the unknown equivalent electric and magnetic currents are expanded using curvilinear RWG basis functions.The resultant matrix equation is then solved by the multilevel fast multipole algorithm (MLFMA) and fast far-field approximation (FAFFA) is used to further accelerate the computation.The radiation patterns of dipole arrays in the presence of radomes are presented.The numerical results demonstrate the accuracy and versatility of this method.
Higher-order multipole amplitude measurement in $\\pspto\\g\\chict$
,
2011-01-01
Using $106\\times10^6$ $\\psp$ events collected with the BESIII detector at the BEPCII storage ring, the higher-order multipole amplitudes in the radiative transition $\\pspto\\g\\chictto\\g\\pp/\\g\\kk$ are measured. A fit to the $\\chict$ production and decay angular distributions yields $M2=0.046\\pm0.010\\pm0.013$ and $E3=0.015\\pm0.008\\pm0.018$, where the first errors are statistical and the second systematic. Here $M2$ denotes the normalized magnetic quadrupole amplitude and $E3$ the normalized electric octupole amplitude. This measurement shows evidence for the existence of the $M2$ signal with $4.4\\sigma$ statistical significance and is consistent with the charm quark having no anomalous magnetic moment.
Mihalcea, Bogdan M; Stan, Cristina; Visan, Gina T; Ganciu, Mihai; Filinov, Vladimir E; Lapitsky, Dmitry S; Deputatova, Lidiya V; Syrovatka, Roman A
2015-01-01
Trapping of microparticles and aerosols is of great interest for physics and chemistry. We report microparticle trapping in multipole linear Paul trap geometries, operating under Standard Ambient Temperature and Pressure (SATP) conditions. An 8-electrode and a 12-electrode linear trap geometries have been designed and tested with an aim to achieve trapping for larger number of particles and to study microparticle dynamical stability in electrodynamic fields. We report emergence of planar and volume ordered structures of the microparticles, depending on the a.c. trapping frequency and particle specific charge ratio. The electric potential within the trap was mapped using the electrolytic tank method. Particle dynamics was simulated using a stochastic Langevin equation. We emphasize extended regions of stable trapping with respect to quadrupole traps, as well as good agreement between experiment and numerical simulations.
Axion like particle Dark Matter may explain the anomalies of CMB multipoles
Yang, Qiaoli
2015-01-01
The axions/axion like particles (ALPs) may constitute a major part of dark matter. Recently people find that dark matter axions can thermalize and form a Bose-Einstein condensate with a long correlation length. For the ALPs the thermalization scenario is similar. We find that for the linear regime of perturbation the ALPs are different from ordinary point like dark matter particles with additional terms in the first order velocity equation. The differences are especially compelling for string theory originated lighter ALPs. Also, axions/ALPs with a long correlation length can be thermalized due to gravitational interaction therefore alter the entropy of large scale. We propose that it can be a mechanism to explain the anomalies of Cosmic Microwave Background (CMB) multipoles if the mass of ALPs is order of $10^{-29}{\\rm eV}$.
Pan Xiaomin; Sheng Xinqing
2008-01-01
A general and efficient parallel approach is proposed for the first time to parallelize the hybrid finite-element-boundary-integral-multi-level fast multipole algorithm (FE-BI-MLFMA). Among many algorithms of FE-BI-MLFMA, the decomposition algorithm (DA) is chosen as a basis for the parallelization of FE-BI-MLFMA because of its distinct numerical characteristics suitable for parallelization. On the basis of the DA, the parallelization of FE-BI-MLFMA is carried out by employing the parallelized multi-frontal method for the matrix from the finite-element method and the parallelized MLFMA for the matrix from the boundary integral method respectively. The programming and numerical experiments of the proposed parallel approach are carried out in the high perfor-mance computing platform CEMS-Liuhui. Numerical experiments demonstrate that FE-BI-MLFMA is efficiently parallelized and its computational capacity is greatly improved without losing accuracy, efficiency, and generality.
Sokalski, W. A.; Shibata, M.; Ornstein, R. L.; Rein, R.
1992-01-01
The quality of several atomic charge models based on different definitions has been analyzed using cumulative atomic multipole moments (CAMM). This formalism can generate higher atomic moments starting from any atomic charges, while preserving the corresponding molecular moments. The atomic charge contribution to the higher molecular moments, as well as to the electrostatic potentials, has been examined for CO and HCN molecules at several different levels of theory. The results clearly show that the electrostatic potential obtained from CAMM expansion is convergent up to R-5 term for all atomic charge models used. This illustrates that higher atomic moments can be used to supplement any atomic charge model to obtain more accurate description of electrostatic properties.
From geodesics of the multipole solutions to the perturbed Kepler problem
Hernandez-Pastora, J L; 10.1103/PhysRevD.82.104001
2010-01-01
A static and axisymmetric solution of the Einstein vacuum equations with a finite number of Relativistic Multipole Moments (RMM) is written in MSA coordinates up to certain order of approximation, and the structure of its metric components is explicitly shown. From the equation of equatorial geodesics we obtain the Binet equation for the orbits and it allows us to determine the gravitational potential that leads to the equivalent classical orbital equations of the perturbed Kepler problem. The relativistic corrections to Keplerian motion are provided by the different contributions of the RMM of the source starting from the Monopole (Schwarzschild correction). In particular, the perihelion precession of the orbit is calculated in terms of the quadrupole and 2$^4$-pole moments. Since the MSA coordinates generalize the Schwarzschild coordinates, the result obtained allows measurement of the relevance of the quadrupole moment in the first order correction to the perihelion frequency-shift.
Giant arachnoid granulation mimicking dural sinus thrombosis.
Ayaz, Ercan; Atalay, Basak; Baysal, Begumhan; Senturk, Senem; Aslan, Ahmet
2017-01-01
Arachnoid granulations (AG) are composed of dense, collagenous connective tissue that includes clusters of arachnoid cells. They tend to invaginate into the dural sinuses, through which cerebrospinal fluid enters the venous system. AG are most commonly seen at the junction between the middle and lateral thirds of the transverse sinuses near the entry sites of the superficial veins. Presently described is the case of a 21-year-old female who presented at the clinic with recurrent headaches. Magnetic resonance (MR) imaging revealed a 3.5-cm lesion, which extended from confluens sinuum through the superior sagittal sinus. The lesion had created a scallop-shaped area of erosion in the neighboring occipital bone. To exclude sinus thrombosis, MR venography was performed, which displayed a maintained venous flow around the lesion. Headaches were treated symptomatically with medical therapy. Giant AG can be misdiagnosed as dural sinus thrombosis. MR imaging combined with MR venography is the most useful diagnostic tool to differentiate giant AG from dural sinus thrombosis.
A giant Ordovician anomalocaridid.
Van Roy, Peter; Briggs, Derek E G
2011-05-26
Anomalocaridids, giant lightly sclerotized invertebrate predators, occur in a number of exceptionally preserved early and middle Cambrian (542-501 million years ago) biotas and have come to symbolize the unfamiliar morphologies displayed by stem organisms in faunas of the Burgess Shale type. They are characterized by a pair of anterior, segmented appendages, a circlet of plates around the mouth, and an elongate segmented trunk lacking true tergites with a pair of flexible lateral lobes per segment. Disarticulated body parts, such as the anterior appendages and oral circlet, had been assigned to a range of taxonomic groups--but the discovery of complete specimens from the middle Cambrian Burgess Shale showed that these disparate elements all belong to a single kind of animal. Phylogenetic analyses support a position of anomalocaridids in the arthropod stem, as a sister group to the euarthropods. The anomalocaridids were the largest animals in Cambrian communities. The youngest unequivocal examples occur in the middle Cambrian Marjum Formation of Utah but an arthropod retaining some anomalocaridid characteristics is present in the Devonian of Germany. Here we report the post-Cambrian occurrence of anomalocaridids, from the Early Ordovician (488-472 million years ago) Fezouata Biota in southeastern Morocco, including specimens larger than any in Cambrian biotas. These giant animals were an important element of some marine communities for about 30 million years longer than previously realized. The Moroccan specimens confirm the presence of a dorsal array of flexible blades attached to a transverse rachis on the trunk segments; these blades probably functioned as gills.
The Giant Magnetocaloric Effect
Pecharsky, Vitalij K.
1998-03-01
Since the discovery of the magnetocaloric effect in pure iron by E.Warburg in 1881, it has been measured experimentally on many magnetic metals and compounds. The majority of the materials studied order magnetically undergoing a second order phase transformation. The magnetocaloric effect, typically peaking near the Curie or the Néel temperature, generally ranges from 0.5 to 2 K (in terms of adiabatic temperature change) or at 1 to 4 J/kg K (in terms of isothermal magnetic entropy change) per 1 T magnetic field change. The giant magnetocaloric effect recently discovered in Gd_5(Si_xGe_1-x)4 alloys, where x refrigerant capacity, which is the measure of how much heat can be transferred from a cold to a hot reservoir in one ideal thermodynamic cycle, is larger than that of the best second order phase transition materials by 25 to 100%. When the Gd_5(Si_xGe_1-x)4 alloys are compared with other known materials, which show first order magnetic phase transition, such as Dy, Ho, Er, HoCo_2, NdMn_2Si_2, Fe_0.49Rh_0.51, and (Hf_0.83Ta_0.17)Fe_2+x, only Fe_0.49Rh_0.51 has comparable magnetocaloric properties. However, the first order magnetic phase transition in Fe_0.49Rh_0.51 is irreversible, and the magnetocaloric effect disappears after one magnetizing/demagnetizing cycle. A study of the crystal structure, thermodynamics, and magnetism of the Gd_5(Si_xGe_1-x)4 alloys, where 0 basic relations between the composition, the crystal structure, and the change in thermodynamics and magnetocaloric properties, which occur in the Gd_5(Si_xGe_1-x)4 system, and which brings about the giant magnetocaloric effect when x <= 0.5.
Lorenzen, Konstantin; Mathias, Gerald; Tavan, Paul
2015-11-14
Hamiltonian Dielectric Solvent (HADES) is a recent method [S. Bauer et al., J. Chem. Phys. 140, 104103 (2014)] which enables atomistic Hamiltonian molecular dynamics (MD) simulations of peptides and proteins in dielectric solvent continua. Such simulations become rapidly impractical for large proteins, because the computational effort of HADES scales quadratically with the number N of atoms. If one tries to achieve linear scaling by applying a fast multipole method (FMM) to the computation of the HADES electrostatics, the Hamiltonian character (conservation of total energy, linear, and angular momenta) may get lost. Here, we show that the Hamiltonian character of HADES can be almost completely preserved, if the structure-adapted fast multipole method (SAMM) as recently redesigned by Lorenzen et al. [J. Chem. Theory Comput. 10, 3244-3259 (2014)] is suitably extended and is chosen as the FMM module. By this extension, the HADES/SAMM forces become exact gradients of the HADES/SAMM energy. Their translational and rotational invariance then guarantees (within the limits of numerical accuracy) the exact conservation of the linear and angular momenta. Also, the total energy is essentially conserved-up to residual algorithmic noise, which is caused by the periodically repeated SAMM interaction list updates. These updates entail very small temporal discontinuities of the force description, because the employed SAMM approximations represent deliberately balanced compromises between accuracy and efficiency. The energy-gradient corrected version of SAMM can also be applied, of course, to MD simulations of all-atom solvent-solute systems enclosed by periodic boundary conditions. However, as we demonstrate in passing, this choice does not offer any serious advantages.
Lorenzen, Konstantin; Mathias, Gerald; Tavan, Paul, E-mail: tavan@physik.uni-muenchen.de [Lehrstuhl für BioMolekulare Optik, Ludig–Maximilians Universität München, Oettingenstr. 67, 80538 München (Germany)
2015-11-14
Hamiltonian Dielectric Solvent (HADES) is a recent method [S. Bauer et al., J. Chem. Phys. 140, 104103 (2014)] which enables atomistic Hamiltonian molecular dynamics (MD) simulations of peptides and proteins in dielectric solvent continua. Such simulations become rapidly impractical for large proteins, because the computational effort of HADES scales quadratically with the number N of atoms. If one tries to achieve linear scaling by applying a fast multipole method (FMM) to the computation of the HADES electrostatics, the Hamiltonian character (conservation of total energy, linear, and angular momenta) may get lost. Here, we show that the Hamiltonian character of HADES can be almost completely preserved, if the structure-adapted fast multipole method (SAMM) as recently redesigned by Lorenzen et al. [J. Chem. Theory Comput. 10, 3244-3259 (2014)] is suitably extended and is chosen as the FMM module. By this extension, the HADES/SAMM forces become exact gradients of the HADES/SAMM energy. Their translational and rotational invariance then guarantees (within the limits of numerical accuracy) the exact conservation of the linear and angular momenta. Also, the total energy is essentially conserved—up to residual algorithmic noise, which is caused by the periodically repeated SAMM interaction list updates. These updates entail very small temporal discontinuities of the force description, because the employed SAMM approximations represent deliberately balanced compromises between accuracy and efficiency. The energy-gradient corrected version of SAMM can also be applied, of course, to MD simulations of all-atom solvent-solute systems enclosed by periodic boundary conditions. However, as we demonstrate in passing, this choice does not offer any serious advantages.
A giant frontoethmoid mucocele with intracranial extension.
Işık, Abdülcemal Ümit; Arslan, Selçuk; Arslan, Erhan; Baykal, Süleyman
2015-02-01
Mucoceles are mucus-containing cysts lined by epithelium. Although benign, they may show expansive growth and remain undiagnosed until symptoms due to compression of surrounding structures arise. We report a rare case of frontoethmoid mucocele with intracranial extension in an 80-year-old woman with complaints of headache, right diplopia and proptosis. A right frontoorbital craniotomy was performed, and a mucocele in the frontal sinus extending into the frontal lobe and orbit was totally removed. The patient was successfully treated without any complication. The two-year follow-up results were satisfactory. Magnetic resonance imaging excluded any recurrence of the mucocele. Combined intranasal and transcranial approach is necessary to treat giant frontoetmoid mucoceles with intracranial extension. © The Author(s) 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.
Electroproduction of the {Delta}(1232) Resonance at High Momentum Transfer
Frolov, V.V.; Adams, G.S.; Davidson, R.M.; Klusman, M.; Mukhopadhyay, N.C.; Napolitano, J.; Nozar, M.; Price, J.W.; Stoler, P.; Witkowski, M. [Physics Department, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Bosted, P. [Physics Department, American University, Washington, D.C. 20016 (United States); Armstrong, C.S.; Meekins, D. [Department of Physics, College of William Mary, Williamsburg, Virginia 23187 (United States); Assamagan, K.; Avery, S.; Baker, O.K.; Eden, T.; Gaskell, D.; Gueye, P.; Hinton, W.; Keppel, C.; Madey, R.; Niculescu, G.; Niculescu, I.; Tang, L. [Physics Department, Hampton University, Hampton, Virginia 23668 (United States); Ahmidouch, A.; Madey, R. [Physics Department, Kent State University, Kent, Ohio 44242 (United States); Kim, W. [Physics Department, Kyungpook National University, Taegu, South (Korea); Baker, O.K.; Burkert, V.; Carlini, R.; Dunne, J.; Ent, R.; Keppel, C.; Mack, D.; Mitchell, J.; Tang, L.; Wood, S. [Thomas Jefferson National Accelerator Facility, Newport News, Virginia 23606 (United States); Koltenuk, D. [Physics Department, University of Pennsylvania, Philadelphia, Pennsylvania 19104 (United States); Minehart, R. [Physics Department, University of Virginia, Charlottesville, Virginia 22903 (United States); Mkrtchyan, H.; Tadevosian, V. [Yerevan Physics Institute, Yerevan (Armenia)
1999-01-01
We studied the electroproduction of the {Delta}(1232) resonance via the reaction p(e,thinspe{sup {prime}}p){pi}{sup 0} at four-momentum transfers Q{sup 2}=2.8 and 4.0 GeV{sup 2} . This is the highest Q{sup 2} for which exclusive resonance electroproduction has ever been observed. Decay angular distributions for {Delta}{r_arrow}p{pi}{sup 0} were measured over a wide range of barycentric energies covering the resonance. The N{endash}{Delta} transition form factor G{sup {asterisk}}{sub M} and ratios of resonant multipoles E{sub 1+}/M{sub 1+} and S{sub 1+}/M{sub 1+} were extracted from the decay angular distributions. These ratios remain small, indicating that perturbative QCD is not applicable for this reaction at these momentum transfers. {copyright} {ital 1998} {ital The American Physical Society }
The Resonant Transneptunian Populations
Gladman, B; Petit, J-M; Kavelaars, J; Jones, R L; Parker, J Wm; Van Laerhoven, C; Nicholson, P; Rousselot, P; Bieryla, A; Ashby, M L N
2012-01-01
The transneptunian objects (TNOs) trapped in mean-motion resonances with Neptune were likely emplaced there during planet migration late in the giant-planet formation process. We perform detailed modelling of the resonant objects detected in the Canada-France Ecliptic Plane Survey (CFEPS) in order to provide population estimates and, for some resonances, constrain the complex internal orbital element distribution. Detection biases play a critical role because phase relationships with Neptune make object discovery more likely at certain longitudes. This paper discusses the 3:2, 5:2, 2:1, 3:1, 5:1, 4:3, 5:3, 7:3, 5:4, and 7:4 mean-motion resonances, all of which had CFEPS detections, along with our upper limit on 1:1 Neptune Trojans (which is consistent with their small population estimated elsewhere). For the plutinos (TNOs in the 3:2 resonance) we refine the orbital element distribution given in Kavelaars et al. (2009) and show that steep H-magnitude distributions (N(H) proportional to 10aH, with a=0.8-0.9) a...
2013-09-01
The Pleistocene megafauna extinction erased a group of remarkable animals. Whether humans had a prominent role in the extinction remains controversial, but it is emerging that the disappearance of the giants has markedly affected the environment.
Atmospheres of Extrasolar Giant Planets
Marley, M S; Seager, S; Barman, T; Marley, Mark S.; Fortney, Jonathan; Seager, Sara; Barman, Travis
2006-01-01
The key to understanding an extrasolar giant planet's spectrum--and hence its detectability and evolution--lies with its atmosphere. Now that direct observations of thermal emission from extrasolar giant planets are in hand, atmosphere models can be used to constrain atmospheric composition, thermal structure, and ultimately the formation and evolution of detected planets. We review the important physical processes that influence the atmospheric structure and evolution of extrasolar giant planets and consider what has already been learned from the first generation of observations and modeling. We pay particular attention to the roles of cloud structure, metallicity, and atmospheric chemistry in affecting detectable properties through Spitzer Space Telescope observations of the transiting giant planets. Our review stresses the uncertainties that ultimately limit our ability to interpret EGP observations. Finally we will conclude with a look to the future as characterization of multiple individual planets in a ...
Atmospheres of Extrasolar Giant Planets
Marley, Mark
2006-01-01
The next decade will almost certainly see the direct imaging of extrasolar giant planets around nearby stars. Unlike purely radial velocity detections, direct imaging will open the door to characterizing the atmosphere and interiors of extrasola planets and ultimately provide clues on their formation and evolution through time. This process has already begun for the transiting planets, placing new constraints on their atmospheric structure, composition, and evolution. Indeed the key to understanding giant planet detectability, interpreting spectra, and constraining effective temperature and hence evolution-is the atmosphere. I will review the universe of extrasolar giant planet models, focusing on what we have already learned from modeling and what we will likely be able to learn from the first generation of direct detection data. In addition to these theoretical considerations, I will review the observations and interpretation of the - transiting hot Jupiters. These objects provide a test of our ability to model exotic atmospheres and challenge our current understanding of giant planet evolution.
Annular Elastolytic Giant Cell Granuloma
Khandpur Sujay
2001-01-01
Full Text Available The clinical and histopathological features of annular elastolytic giant cell granuloma in a 42â€"year-old female patient are described. The condition presented as annular erythematous plaques over sun- exposed skin sparing the face. Histopathology revealed dense granulomatous infiltrate consisting of numerous giant cells and lymphohistiocytes without any palisading arrangement or necrobiosis. The features differentiating it from other similar granulomatous disorders are discussed.
Resonant Removal of Exomoons During Planetary Migration
Spalding, Christopher; Adams, Fred C
2015-01-01
Jupiter and Saturn play host to an impressive array of satellites, making it reasonable to suspect that similar systems of moons might exist around giant extrasolar planets. Furthermore, a significant population of such planets is known to reside at distances of several Astronomical Units (AU), leading to speculation that some moons thereof might support liquid water on their surfaces. However, giant planets are thought to undergo inward migration within their natal protoplanetary disks, suggesting that gas giants currently occupying their host star's habitable zone formed further out. Here we show that when a moon-hosting planet undergoes inward migration, dynamical interactions may naturally destroy the moon through capture into a so-called "evection resonance." Within this resonance, the lunar orbit's eccentricity grows until the moon eventually collides with the planet. Our work suggests that moons orbiting within about 10 planetary radii are susceptible to this mechanism, with the exact number dependent ...
James Kelly; et. Al.
2005-09-01
We measured angular distributions of differential cross section, beam analyzing power, and recoil polarization for neutral pion electroproduction at Q{sup 2} = 1.0 (GeV/c){sup 2} in 10 bins of W across the Delta resonance. A total of 16 independent response functions were extracted, of which 12 were observed for the first time. Comparisons with recent model calculations show that response functions governed by real parts of interference products are determined relatively well near 1.232 GeV, but variations among models is large for response functions governed by imaginary parts and for both increases rapidly with W. We performed a nearly model-independent multipole analysis that adjusts complex multipoles with high partial waves constrained by baseline models. Parabolic fits to the W dependence of the multipole analysis around the Delta mass gives values for SMR = (-6.61 +/- 0.18)% and EMR = (-2.87 +/- 0.19)% that are distinctly larger than those from Legendre analysis of the same data. Similarly, the multipole analysis gives Re(S0+/M1+) = (+7.1 +/- 0.8)% at W=1.232 GeV, consistent with recent models, while the traditional Legendre analysis gives the opposite sign because its truncation errors are quite severe. Finally, using a unitary isobar model (UIM), we find that excitation of the Roper resonance is dominantly longitudinal with S1/2 = (0.05 +/- 0.01) GeV{sup (-1/2)} at Q{sup 2}=1. The ReS0+ and ReE0+ multipoles favor pseudovector coupling over pseudoscalar coupling or a recently proposed mixed-coupling scheme, but the UIM does not reproduce the imaginary parts of 0+ multipoles well.
A Case of Giant Uterine Lipoleiomyoma Simulating Malignancy.
Karaman, Erbil; Çim, Numan; Bulut, Gülay; Elçi, Gülhan; Andıç, Esra; Tekin, Mustafa; Kolusarı, Ali
2015-01-01
Introduction. Uterine leiomyoma is the most common benign pathology in women and lipoleiomyoma is an extremely rare and specific type of leiomyoma. Here, we report an unusual case of giant pedunculated subserous lipoleiomyoma misdiagnosed preoperatively as leiomyosarcoma. Case. A 45-year-old woman admitted to our gynecology outpatient clinic for complaints of abdominal distention, tiredness, and pelvic pain for the last 6 months. Sonography and abdominal magnetic resonance imaging (MRI) showed a giant semisolid mass that filled whole abdominal cavity from pelvis to subdiaphragmatic area. A primary diagnosis of uterine sarcoma or ovarian malignancy was made. On operation, total abdominal hysterectomy with a pedunculated mass of size 30 × 23 × 12 cm and weighing 5.4 kg and bilateral salpingo-oophorectomy were performed. The histopathology revealed a lipoleiomyoma with extensive cystic and fatty degeneration without any malignancy. Discussion. The diagnosis of leiomyoma is done usually with pelvic ultrasound but sometimes it is difficult to reach a correct diagnosis especially in cases of giant and pedunculated lipoleiomyoma that included fatty tissue which may mimick malignancy. Conclusion. Subserous pedunculated giant lipoleiomyoma should be kept in mind in the differential diagnosis of leiomyosarcoma or ovarian malignancy.
A Case of Giant Uterine Lipoleiomyoma Simulating Malignancy
Erbil Karaman
2015-01-01
Full Text Available Introduction. Uterine leiomyoma is the most common benign pathology in women and lipoleiomyoma is an extremely rare and specific type of leiomyoma. Here, we report an unusual case of giant pedunculated subserous lipoleiomyoma misdiagnosed preoperatively as leiomyosarcoma. Case. A 45-year-old woman admitted to our gynecology outpatient clinic for complaints of abdominal distention, tiredness, and pelvic pain for the last 6 months. Sonography and abdominal magnetic resonance imaging (MRI showed a giant semisolid mass that filled whole abdominal cavity from pelvis to subdiaphragmatic area. A primary diagnosis of uterine sarcoma or ovarian malignancy was made. On operation, total abdominal hysterectomy with a pedunculated mass of size 30 × 23 × 12 cm and weighing 5.4 kg and bilateral salpingo-oophorectomy were performed. The histopathology revealed a lipoleiomyoma with extensive cystic and fatty degeneration without any malignancy. Discussion. The diagnosis of leiomyoma is done usually with pelvic ultrasound but sometimes it is difficult to reach a correct diagnosis especially in cases of giant and pedunculated lipoleiomyoma that included fatty tissue which may mimick malignancy. Conclusion. Subserous pedunculated giant lipoleiomyoma should be kept in mind in the differential diagnosis of leiomyosarcoma or ovarian malignancy.
5s correlation confinement resonances in Xe-endo-fullerenes
Dolmatov, V K
2011-01-01
Spectacular trends in the modification of the Xe 5s photoionization via interchannel coupling with confinement resonances emerging in the Xe 4d giant resonance upon photoionization of the Xe@C60, Xe@C240 and Xe@C60@C240 endo-fullerenes are theoretically unraveled and interpreted.
2001-01-01
Their work goes on unseen, because they a hundred metres beneath your feet. But while the race against the clock to build the LHC has begun on the surface, teams underground are feverishly engaged to dismantle LEP and its experiments. Four months after the start of dismantling, the technical coordinators of the different experiments discuss the progress of work. Little men attack the giant ALEPH. The barrel and its two endcaps have been removed to the end of the cavern and stripped of their cables. The breaking up of the detector can now begin. At ALEPH, counting rooms removed all in one go Jean-Paul Fabre, technical coordinator at ALEPH:'After making safe the structure, the first step was to remove the wiring and cables. Some 210 cubic metres were brought out. Then the counting rooms all round the detector were taken out. They were brought up from the cavern all in one go, up through the shaft, which is 10 metres wide and 150 metres deep. They made it with 15 centimetres to spare. They have been emptied of...
Giant high occipital encephalocele
Agrawal Amit
2016-03-01
Full Text Available Encephaloceles are rare embryological mesenchymal developmental anomalies resulting from inappropriate ossification in skull through with herniation of intracranial contents of the sac. Encephaloceles are classified based on location of the osseous defect and contents of sac. Convexity encephalocele with osseous defect in occipital bone is called occipital encephalocele. Giant occipital encephaloceles can be sometimes larger than the size of baby skull itself and they pose a great surgical challenge. Occipital encephaloceles (OE are further classified as high OE when defect is only in occipital bone above the foramen magnum, low OE when involving occipital bone and foramen magnum and occipito-cervical when there involvement of occipital bone, foramen magnum and posterior upper neural arches. Chiari III malformation can be associated with high or low occipital encephaloceles. Pre-operatively, it is essential to know the size of the sac, contents of the sac, relation to the adjacent structures, presence or absence of venous sinuses/vascular structures and osseous defect size. Sometimes it becomes imperative to perform both CT and MRI for the necessary information. Volume rendered CT images can depict the relation of osseous defect to foramen magnum and provide information about upper neural arches which is necessary in classifying these lesions.
Ninan, Jem; Lester, Susan; Hill, Catherine
2016-02-01
Giant cell arteritis (GCA) is the most common vasculitis of the elderly. The diagnosis can be challenging at times because of the limitation of the American Rheumatology Association (ARA) classification criteria and the significant proportion of biopsy-negative patients with GCA. We discuss the role of advanced imaging techniques, including positron emission tomography (PET) scanning, in establishing diagnosis and improved histopathology techniques to improve the sensitivity of temporal artery biopsy. There have been significant advances in the understanding of the pathogenesis of GCA, particularly the role of cytokine pathways such as the interleukins, IL-6-IL-17 axis, and the IL-12-interferon-γ axis and their implication for new therapies. We highlight that glucocorticoids remain the primary treatment for GCA, but recognize the risk of steroid-induced side effects. A number of pharmacotherapies to enable glucocorticoid dose reduction and prevent relapse have been studied. Early diagnosis and fast-track pathways have improved outcomes by encouraging adherence to evidence-based practice. Copyright © 2016 Elsevier Ltd. All rights reserved.
Kissin, Yevgeni
2015-01-01
The internal rotation of post-main sequence stars is investigated, in response to the convective pumping of angular momentum toward the stellar core, combined with a tight magnetic coupling between core and envelope. The spin evolution is calculated using model stars of initial mass 1, 1.5 and $5\\,M_\\odot$, taking into account mass loss on the giant branches and the partitioning of angular momentum between the outer and inner envelope. We also include the deposition of orbital angular momentum from a sub-stellar companion, as influenced by tidal drag as well as the excitation of orbital eccentricity by a fluctuating gravitational quadrupole moment. A range of angular velocity profiles $\\Omega(r)$ is considered in the deep convective envelope, ranging from solid rotation to constant specific angular momentum. We focus on the backreaction of the Coriolis force on the inward pumping of angular momentum, and the threshold for dynamo action in the inner envelope. Quantitative agreement with measurements of core ro...
Imaging Extrasolar Giant Planets
Bowler, Brendan P
2016-01-01
High-contrast adaptive optics imaging is a powerful technique to probe the architectures of planetary systems from the outside-in and survey the atmospheres of self-luminous giant planets. Direct imaging has rapidly matured over the past decade and especially the last few years with the advent of high-order adaptive optics systems, dedicated planet-finding instruments with specialized coronagraphs, and innovative observing and post-processing strategies to suppress speckle noise. This review summarizes recent progress in high-contrast imaging with particular emphasis on observational results, discoveries near and below the deuterium-burning limit, and a practical overview of large-scale surveys and dedicated instruments. I conclude with a statistical meta-analysis of deep imaging surveys in the literature. Based on observations of 384 unique and single young ($\\approx$5--300~Myr) stars spanning stellar masses between 0.1--3.0~\\Msun, the overall occurrence rate of 5--13~\\Mjup \\ companions at orbital distances ...
Simmonett, Andrew C.; Pickard, Frank C.; Schaefer, Henry F.; Brooks, Bernard R.
2014-05-01
Next-generation molecular force fields deliver accurate descriptions of non-covalent interactions by employing more elaborate functional forms than their predecessors. Much work has been dedicated to improving the description of the electrostatic potential (ESP) generated by these force fields. A common approach to improving the ESP is by augmenting the point charges on each center with higher-order multipole moments. The resulting anisotropy greatly improves the directionality of the non-covalent bonding, with a concomitant increase in computational cost. In this work, we develop an efficient strategy for enumerating multipole interactions, by casting an efficient spherical harmonic based approach within a particle mesh Ewald (PME) framework. Although the derivation involves lengthy algebra, the final expressions are relatively compact, yielding an approach that can efficiently handle both finite and periodic systems without imposing any approximations beyond PME. Forces and torques are readily obtained, making our method well suited to modern molecular dynamics simulations.
Multipole generator wind energy converter without gearbox and with variable speed
Wortmann, B.; Hansen, L.H.
2000-01-01
The idea of this industrial research project was a totally new concept of WTG for NEG Micon A/S. The result has been a multiple range of concepts. Siemens realised a complete design and construction of a multipole PMG generator. However, it was soon recognised that the multipole synchronous PMG concept of Siemens was too expensive. The change to a WRG concept improved the situation. However, it is still doubtful if an economic feasible solution can be obtained for use in a WTG. Evidently, it is necessary looking on other concepts of synchronous generators for wind energy conversion. One way of verifying the economic feasibility was to clarify uncertainty about necessary support technologies. Two support technologies were investigated: variable speed control and blade turning system. Both systems turned out to be interesting concepts on their own. A complete specification of the safety and control strategy for variable speed was developed within this project. The strategy was implemented onthe test WTG on the test site of Risoe National Laboratory. The test set-up is very flexible and is based on the use of a Siemens IGBT Frequency Converter. The WTG can be operated as a conventional stall regulated WTG or as variable speed WTG. For calculation purpose HawC has been enlarged as a first step by the possibility to simulate a stall controlled WTG equipped with an asynchronous generator. Various tests on loads and electrical grid quality can be realised for this case. The second element of the project was the blade turning system, A full scale test set-up made a lifecycle test program possible. Many new tools and valuable knowledge were gathered and developed. The FLEX 4 load calculation program has been adapted to active stall operation. The results of the project were very promising. Today, this research forms the basis for NEG Migon A/S active stall concept on the NM 2000. The project has broaden ed NEG Micon A/S horizon for new control strategies. New areas for
Constructing the secular architecture of the solar system I: The giant planets
Alessandro, Morbidelli; Tsiganis, Kleomenis; Gomes, Rodney; Levison, Harold F
2009-01-01
Using numerical simulations, we show that smooth migration of the giant planets through a planetesimal disk leads to an orbital architecture that is inconsistent with the current one: the resulting eccentricities and inclinations of their orbits are too small. The crossing of mutual mean motion resonances by the planets would excite their orbital eccentricities but not their orbital inclinations. Moreover, the amplitudes of the eigenmodes characterising the current secular evolution of the eccentricities of Jupiter and Saturn would not be reproduced correctly; only one eigenmode is excited by resonance-crossing. We show that, at the very least, encounters between Saturn and one of the ice giants (Uranus or Neptune) need to have occurred, in order to reproduce the current secular properties of the giant planets, in particular the amplitude of the two strongest eigenmodes in the eccentricities of Jupiter and Saturn.
Arthroscopic Decompression for a Giant Meniscal Cyst.
Ohishi, Tsuyoshi; Suzuki, Daisuke; Matsuyama, Yukihiro
2016-01-01
The authors report the case of a giant medial meniscal cyst in an osteoarthritic knee of an 82-year-old woman that was successfully treated with only arthroscopic cyst decompression. The patient noticed a painful mass on the medial side of the right knee that had been gradually growing for 5 years. Magnetic resonance imaging showed an encapsulated large medial cystic mass measuring 80×65×40 mm that was adjacent to the medial meniscus. An accompanying horizontal tear was also detected in the middle and posterior segments of the meniscus. The medial meniscus was resected up to the capsular attachment to create bidirectional flow between the joint and the cyst with arthroscopic surgery. Magnetic resonance imaging performed 14 months postoperatively showed that the cyst had completely disappeared, and no recurrence was observed during a 2-year follow-up period. An excellent result could be obtained by performing limited meniscectomy to create a channel leading to the meniscal cyst, even though the cyst was large. Among previously reported cases of meniscal cysts, this case is the largest to be treated arthroscopically without open excision.
Völlinger, C
2000-01-01
This note presents a scheme for compensating the persistent current multipole errors of the LHC dipoles by making the coil protection sheets from soft magnetic material of 0.5 mm thickness. The material properties assumed in this study are those of iron sheets with a very low content of impurities (99.99% pure Fe). The non-linearities in the upramp cycle on the b3 multipole component can be reduced by the factor of four (while decreasing the b5 variation by the factor of two. Using sheets of slightly different thicknesses offers a tuning possibility for the series magnet coils and can compensate deviations arising from cables of different suppliers. The calculation method is based on a semi-analytical hysteresis model for hard superconductors and an M(B) - iteration using the method of coupled boundary elements - finite elements (BEM - FEM). It is now possible to compute persistent current multipole errors of geometries with arbitrarily shaped iron yokes and thin layers of soft magnetic material such as tunin...
Ruamps, Renaud; Maurice, Remi; Batchelor, Luke; Boggio-Pasqua, Martial; Guillot, Regis; Barra, Anne Laure; Liu, Junjie; Bendeif, El-Eulmi; Pillet, Sebastien; Hill, Stephen; Mallah, Talal; Guihery, Nathalie
2013-01-01
This paper reports the experimental and theoretical investigations of two trigonal bipyramidal Ni(II) complexes, [Ni(Me(6)tren)Cl](ClO4) (1) and [Ni(Me(6)tren)Br](Br) (2). High-field, high-frequency electron paramagnetic resonance spectroscopy performed on a single crystal of 1 shows a giant uniaxia
Ruamps, Renaud; Maurice, Remi; Batchelor, Luke; Boggio-Pasqua, Martial; Guillot, Regis; Barra, Anne Laure; Liu, Junjie; Bendeif, El-Eulmi; Pillet, Sebastien; Hill, Stephen; Mallah, Talal; Guihery, Nathalie
2013-01-01
This paper reports the experimental and theoretical investigations of two trigonal bipyramidal Ni(II) complexes, [Ni(Me(6)tren)Cl](ClO4) (1) and [Ni(Me(6)tren)Br](Br) (2). High-field, high-frequency electron paramagnetic resonance spectroscopy performed on a single crystal of 1 shows a giant
Leonardo Da Vinci’s giant crossbow
Landrus, Matt
2010-01-01
Leonardo's Giant Crossbow is one of his least understood drawings. This fascinating book offers the first in-depth account of its likely purpose and its highly resolved design. It presents original research and new discoveries about the giant crossbow.
Highly sensitive surface plasmon resonance chemical sensor based on Goos-Hanchen effects
Yin, Xiaobo; Hesselink, Lambertus
2006-08-01
The resonance enhanced Goos-Hanchen shifts at attenuated total internal reflection enables the possibility for highly sensitive surface plasmon resonance sensor. The observed giant displacements result from the singular phase retardation at the resonance where the phase is continuous but changes dramatically. The phenomenon is proposed for chemical sensing and the superior sensitivity is demonstrated.
Atmospheres of Extrasolar Giant Planets
Marley, M. S.; Fortney, J.; Seager, S.; Barman, T.
The key to understanding an extrasolar giant planet's spectrum - and hence its detectability and evolution - lies with its atmosphere. Now that direct observations of thermal emission from extrasolar giant planets (EGPs) are in hand, atmosphere models can be used to constrain atmospheric composition, thermal structure, and ultimately the formation and evolution of detected planets. We review the important physical processes that influence the atmospheric structure and evolution of EGPs and consider what has already been learned from the first generation of observations and modeling. We pay particular attention to the roles of cloud structure, metallicity, and atmospheric chemistry in affecting detectable properties through Spitzer Space Telescope observations of the transiting giant planets. Our review stresses the uncertainties that ultimately limit our ability to interpret EGP observations. Finally we will conclude with a look to the future as characterization of multiple individual planets in a single stellar system leads to the study of comparative planetary architectures.
Giant lobelias exemplify convergent evolution.
Givnish, Thomas J
2010-01-14
Giant lobeliads on tropical mountains in East Africa and Hawaii have highly unusual, giant-rosette growth forms that appear to be convergent on each other and on those of several independently evolved groups of Asteraceae and other families. A recent phylogenetic analysis by Antonelli, based on sequencing the widest selection of lobeliads to date, raises doubts about this paradigmatic example of convergent evolution. Here I address the kinds of evidence needed to test for convergent evolution and argue that the analysis by Antonelli fails on four points. Antonelli's analysis makes several important contributions to our understanding of lobeliad evolution and geographic spread, but his claim regarding convergence appears to be invalid. Giant lobeliads in Hawaii and Africa represent paradigmatic examples of convergent evolution.
Giant lobelias exemplify convergent evolution
Givnish Thomas J
2010-01-01
Full Text Available Abstract Giant lobeliads on tropical mountains in East Africa and Hawaii have highly unusual, giant-rosette growth forms that appear to be convergent on each other and on those of several independently evolved groups of Asteraceae and other families. A recent phylogenetic analysis by Antonelli, based on sequencing the widest selection of lobeliads to date, raises doubts about this paradigmatic example of convergent evolution. Here I address the kinds of evidence needed to test for convergent evolution and argue that the analysis by Antonelli fails on four points. Antonelli's analysis makes several important contributions to our understanding of lobeliad evolution and geographic spread, but his claim regarding convergence appears to be invalid. Giant lobeliads in Hawaii and Africa represent paradigmatic examples of convergent evolution.
Structure of giant muscle proteins
Nathan Thompson Wright
2013-12-01
Full Text Available Giant muscle proteins (e.g. titin, nebulin, and obscurin play a seminal role in muscle elasticity, stretch response, and sarcomeric organization. Each giant protein consists of multiple tandem structural domains, usually arranged in a modular fashion ranging from 500 kDa to 4 MDa. Although many of the domains are similar in structure, subtle differences create a unique function of each domain. Recent high and low resolution structural and dynamic studies now suggest more nuanced overall protein structures than previously realized. These findings show that atomic structure, interactions between tandem domains, and intrasarcomeric environment all influence the shape, motion, and therefore function of giant proteins. In this article we will review the current understanding of titin, obscurin, and nebulin structure, from the atomic level through the molecular level.
Low loss pole configuration for multi-pole homopolar magnetic bearings
Blumenstock, Kenneth A. (Inventor); Hakun, Claef F. (Inventor)
2001-01-01
A new pole configuration for multi-pole homopolar bearings proposed in this invention reduces rotational losses caused by eddy-currents generated when non-uniform flux distributions exist along the rotor surfaces. The new homopolar magnetic bearing includes a stator with reduced pole-to-pole and exhibits a much more uniform rotor flux than with large pole-to-pole gaps. A pole feature called a pole-link is incorporated into the low-loss poles to provide a uniform pole-to-pole gap and a controlled path for pole-to-pole flux. In order to implement the low-loss pole configuration of magnetic bearings with small pole-to-pole gaps, a new stator configuration was developed to facilitate installation of coil windings. The stator was divided into sector shaped pieces, as many pieces as there are poles. Each sector-shaped pole-piece can be wound on a standard coil winding machine, and it is practical to wind precision layer wound coils. To achieve maximum actuation efficiency, it is desirable to use all the available space for the coil formed by the natural geometric configuration. Then, the coils can be wound in a tapered shape. After winding, the sectored-pole-pieces are installed into and fastened by bonding or other means, to a ring of material which encloses the sectored-pole-pieces, forming a complete stator.
Combining the multilevel fast multipole method with the uniform geometrical theory of diffraction
A. Tzoulis
2005-01-01
Full Text Available The presence of arbitrarily shaped and electrically large objects in the same environment leads to hybridization of the Method of Moments (MoM with the Uniform Geometrical Theory of Diffraction (UTD. The computation and memory complexity of the MoM solution is improved with the Multilevel Fast Multipole Method (MLFMM. By expanding the k-space integrals in spherical harmonics, further considerable amount of memory can be saved without compromising accuracy and numerical speed. However, until now MoM-UTD hybrid methods are restricted to conventional MoM formulations only with Electric Field Integral Equation (EFIE. In this contribution, a MLFMM-UTD hybridization for Combined Field Integral Equation (CFIE is proposed and applied within a hybrid Finite Element - Boundary Integral (FEBI technique. The MLFMM-UTD hybridization is performed at the translation procedure on the various levels of the MLFMM, using a far-field approximation of the corresponding translation operator. The formulation of this new hybrid technique is presented, as well as numerical results.
Application of Fast Multipole Methods to the NASA Fast Scattering Code
Dunn, Mark H.; Tinetti, Ana F.
2008-01-01
The NASA Fast Scattering Code (FSC) is a versatile noise prediction program designed to conduct aeroacoustic noise reduction studies. The equivalent source method is used to solve an exterior Helmholtz boundary value problem with an impedance type boundary condition. The solution process in FSC v2.0 requires direct manipulation of a large, dense system of linear equations, limiting the applicability of the code to small scales and/or moderate excitation frequencies. Recent advances in the use of Fast Multipole Methods (FMM) for solving scattering problems, coupled with sparse linear algebra techniques, suggest that a substantial reduction in computer resource utilization over conventional solution approaches can be obtained. Implementation of the single level FMM (SLFMM) and a variant of the Conjugate Gradient Method (CGM) into the FSC is discussed in this paper. The culmination of this effort, FSC v3.0, was used to generate solutions for three configurations of interest. Benchmarking against previously obtained simulations indicate that a twenty-fold reduction in computational memory and up to a four-fold reduction in computer time have been achieved on a single processor.
Multipole expansion of Green's function for guided waves in a transversely isotropic plate
Lee, Heung Son; Kim, Yoon Young [Seoul National University, Seoul (Korea, Republic of)
2015-05-15
The multipole expansion of Green's function in a transversely isotropic plate is derived based on the eigenfunction expansion method. For the derivation, Green's function is expressed in a bilinear form composed of the regular and singular Lamb-type (or shear-horizontal) wave eigenfunctions. The specific form of the derived Green's function facilitates the handling of general scattering problems in an elastic plate when numerical methods such as the methods of the null-field integral equations are employed. In the derivation, the integral transform of an arbitrary guided wave field is first constructed by the Lamb-type and shear horizontal wave eigenfunctions that work as the kernel functions. After showing that the thickness-dependent parts of the eigenfunctions are orthogonal to each other in the transformed space, Green's function is explicitly derived by using the orthogonality. As an application of the derived Green's function, a scattering problem is solved by the transition matrix method.
Petascale molecular dynamics simulation using the fast multipole method on K computer
Ohno, Yousuke
2014-10-01
In this paper, we report all-atom simulations of molecular crowding - a result from the full node simulation on the "K computer", which is a 10-PFLOPS supercomputer in Japan. The capability of this machine enables us to perform simulation of crowded cellular environments, which are more realistic compared to conventional MD simulations where proteins are simulated in isolation. Living cells are "crowded" because macromolecules comprise ∼30% of their molecular weight. Recently, the effects of crowded cellular environments on protein stability have been revealed through in-cell NMR spectroscopy. To measure the performance of the "K computer", we performed all-atom classical molecular dynamics simulations of two systems: target proteins in a solvent, and target proteins in an environment of molecular crowders that mimic the conditions of a living cell. Using the full system, we achieved 4.4 PFLOPS during a 520 million-atom simulation with cutoff of 28 Å. Furthermore, we discuss the performance and scaling of fast multipole methods for molecular dynamics simulations on the "K computer", as well as comparisons with Ewald summation methods. © 2014 Elsevier B.V. All rights reserved.
Some Physical Consequences of Abrupt Changes in the Multipole Moments of a Gravitating Body
Barrabès, C; Hogan, P A
1997-01-01
The Barrabès-Israel theory of light-like shells in General Relativity= is used to show explicitly that in general a light-like shell is accompanied= by an impulsive gravitational wave. The gravitational wave is identified by = its Petrov Type N contribution to a Dirac delta-function term in the Weyl conformal curvature tensor (with the delta-function singular on the null hypersurface history of the wave and shell). An example is described in w= hich an asymptotically flat static vacuum Weyl space-time experiences a sudden change across a null hypersurface in the multipole moments of its isolate= d axially symmetric source. A light-like shell and an impulsive gravitation= al wave are identified, both having the null hypersurface as history. The stress-energy in the shell is dominated (at large distance from the sourc= e) by the jump in the monopole moment (the mass) of the source with the jump in= the quadrupole moment mainly responsible for the stress being anisotropic. Th= e gravitational wave owes its exis...
Schwörer, Magnus; Lorenzen, Konstantin; Mathias, Gerald; Tavan, Paul, E-mail: paul.tavan@physik.uni-muenchen.de [Lehrstuhl für BioMolekulare Optik, Ludwig–Maximilians Universität München, Oettingenstr. 67, 80538 München (Germany)
2015-03-14
Recently, a novel approach to hybrid quantum mechanics/molecular mechanics (QM/MM) molecular dynamics (MD) simulations has been suggested [Schwörer et al., J. Chem. Phys. 138, 244103 (2013)]. Here, the forces acting on the atoms are calculated by grid-based density functional theory (DFT) for a solute molecule and by a polarizable molecular mechanics (PMM) force field for a large solvent environment composed of several 10{sup 3}-10{sup 5} molecules as negative gradients of a DFT/PMM hybrid Hamiltonian. The electrostatic interactions are efficiently described by a hierarchical fast multipole method (FMM). Adopting recent progress of this FMM technique [Lorenzen et al., J. Chem. Theory Comput. 10, 3244 (2014)], which particularly entails a strictly linear scaling of the computational effort with the system size, and adapting this revised FMM approach to the computation of the interactions between the DFT and PMM fragments of a simulation system, here, we show how one can further enhance the efficiency and accuracy of such DFT/PMM-MD simulations. The resulting gain of total performance, as measured for alanine dipeptide (DFT) embedded in water (PMM) by the product of the gains in efficiency and accuracy, amounts to about one order of magnitude. We also demonstrate that the jointly parallelized implementation of the DFT and PMM-MD parts of the computation enables the efficient use of high-performance computing systems. The associated software is available online.
Stability of spherically symmetric, charged black holes and multipole moments for stationary systems
Gursel, H.Y.
1983-01-01
This dissertation is written in two parts. Part I deals with the question of stability of a spherically symmetric, charged black hole against scalar, electromagnetic, and gravitational perturbations. It consists of two papers written in collaboration with Igor D. Novikov, Vernon D. Sandberg and A.A. Starobinsky. In these papers the dynamical evolution of these perturbations on the interior of a Reissner-Nordstrom black hole is described. The instability of the hole's Cauchy horizon is discussed in detail in terms of the energy densities of the test fields as measured by a freely falling observer approaching the Cauchy horizon. It is concluded that the Cauchy horizon of the analytically extended Reissner-Nordstrom solution is highly unstable and not a physical feature of a realistic gravitational collapse. Part II of this dissertation addresses two problems closely connected with multipole structure of stationary, asymptotically flat spacetimes. It consists of two papers written in collaboration with Kip S. Thorne. The first one shows the equivalence of the moments defined by Kip S. Thorne and the moments defined by Robert Geroch and Richard Hansen. The second proves a conjecture by Kip S. Thorne: In the limit of ''slow'' motion, general relativistic gravity produces no changes whatsoever in the classical Euler equations of rigid body motion. This conjecture is proved by giving an algorithm for generating rigidly rotating solutions of Einstein's equation from nonrotating, static solutions.
Inexact Krylov iterations and relaxation strategies with fast-multipole boundary element method
Layton, Simon K
2015-01-01
Boundary element methods produce dense linear systems that can be accelerated via multipole expansions. Solved with Krylov methods, this implies computing the matrix-vector products within each iteration with some error, at an accuracy controlled by the order of the expansion, $p$. We take advantage of a unique property of Krylov iterations that allow lower accuracy of the matrix-vector products as convergence proceeds, and propose a relaxation strategy based on progressively decreasing $p$. Via extensive numerical tests, we show that the relaxed Krylov iterations converge with speed-ups of between 2x and 4x for Laplace problems and between 3.5x and 4.5x for Stokes problems. We include an application to Stokes flow around red blood cells, computing with up to 64 cells and problem size up to 131k boundary elements and nearly 400k unknowns. The study was done with an in-house multi-threaded C++ code, on a quad-core CPU.
Coe, J P; Paterson, M J
2013-01-01
The method of Monte Carlo configuration interaction (MCCI) [1,2] is applied to the calculation of multipole moments. We look at the ground and excited state dipole moments in carbon monoxide. We then consider the dipole of NO, the quadrupole of the nitrogen molecule and of BH. An octupole of methane is also calculated. We consider experimental geometries and also stretched bonds. We show that these non-variational quantities may be found to relatively good accuracy when compared with FCI results, yet using only a small fraction of the full configuration interaction space. MCCI results in the aug-cc-pVDZ basis are seen to generally have reasonably good agreement with experiment. We also investigate the performance of MCCI when applied to ionisation energies and electron affinities of atoms in an aug-cc-pVQZ basis. We compare the MCCI results with full configuration-interaction quantum Monte Carlo [3,4] and `exact' non-relativistic results [3,4]. We show that MCCI could be a useful alternative for the calculati...
A Generalized Grid-Based Fast Multipole Method for Integrating Helmholtz Kernels.
Parkkinen, Pauli; Losilla, Sergio A; Solala, Eelis; Toivanen, Elias A; Xu, Wen-Hua; Sundholm, Dage
2017-02-14
A grid-based fast multipole method (GB-FMM) for optimizing three-dimensional (3D) numerical molecular orbitals in the bubbles and cube double basis has been developed and implemented. The present GB-FMM method is a generalization of our recently published GB-FMM approach for numerically calculating electrostatic potentials and two-electron interaction energies. The orbital optimization is performed by integrating the Helmholtz kernel in the double basis. The steep part of the functions in the vicinity of the nuclei is represented by one-center bubbles functions, whereas the remaining cube part is expanded on an equidistant 3D grid. The integration of the bubbles part is treated by using one-center expansions of the Helmholtz kernel in spherical harmonics multiplied with modified spherical Bessel functions of the first and second kind, analogously to the numerical inward and outward integration approach for calculating two-electron interaction potentials in atomic structure calculations. The expressions and algorithms for massively parallel calculations on general purpose graphics processing units (GPGPU) are described. The accuracy and the correctness of the implementation has been checked by performing Hartree-Fock self-consistent-field calculations (HF-SCF) on H2, H2O, and CO. Our calculations show that an accuracy of 10(-4) to 10(-7) Eh can be reached in HF-SCF calculations on general molecules.
Revision of FMM-Yukawa: An adaptive fast multipole method for screened Coulomb interactions
Zhang, Bo; Huang, Jingfang; Pitsianis, Nikos P.; Sun, Xiaobai
2010-12-01
FMM-YUKAWA is a mathematical software package primarily for rapid evaluation of the screened Coulomb interactions of N particles in three dimensional space. Since its release, we have revised and re-organized the data structure, software architecture, and user interface, for the purpose of enabling more flexible, broader and easier use of the package. The package and its documentation are available at http://www.fastmultipole.org/, along with a few other closely related mathematical software packages. New version program summaryProgram title: FMM-Yukawa Catalogue identifier: AEEQ_v2_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEEQ_v2_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU GPL 2.0 No. of lines in distributed program, including test data, etc.: 78 704 No. of bytes in distributed program, including test data, etc.: 854 265 Distribution format: tar.gz Programming language: FORTRAN 77, FORTRAN 90, and C. Requires gcc and gfortran version 4.4.3 or later Computer: All Operating system: Any Classification: 4.8, 4.12 Catalogue identifier of previous version: AEEQ_v1_0 Journal reference of previous version: Comput. Phys. Comm. 180 (2009) 2331 Does the new version supersede the previous version?: Yes Nature of problem: To evaluate the screened Coulomb potential and force field of N charged particles, and to evaluate a convolution type integral where the Green's function is the fundamental solution of the modified Helmholtz equation. Solution method: The new version of fast multipole method (FMM) that diagonalizes the multipole-to-local translation operator is applied with the tree structure adaptive to sample particle locations. Reasons for new version: To handle much larger particle ensembles, to enable the iterative use of the subroutines in a solver, and to remove potential contention in assignments for parallelization. Summary of revisions: The software package FMM-Yukawa has been
MULTIPOLE GRAVITATIONAL LENSING AND HIGH-ORDER PERTURBATIONS ON THE QUADRUPOLE LENS
Chu, Z.; Lin, W. P. [Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030 (China); Li, G. L. [Purple Mountain Observatory, 2 West Beijing Road, Nanjing 210008 (China); Kang, X., E-mail: chuzhe@shao.ac.cn, E-mail: linwp@shao.ac.cn [Partner Group of MPI for Astronomy, Purple Mountain Observatory, 2 West Beijing Road, Nanjing 210008 (China)
2013-03-10
An arbitrary surface mass density of the gravitational lens can be decomposed into multipole components. We simulate the ray tracing for the multipolar mass distribution of the generalized Singular Isothermal Sphere model based on deflection angles, which are analytically calculated. The magnification patterns in the source plane are then derived from an inverse shooting technique. As has been found, the caustics of odd mode lenses are composed of two overlapping layers for some lens models. When a point source traverses this kind of overlapping caustics, the image numbers change by {+-}4, rather than {+-}2. There are two kinds of caustic images. One is the critical curve and the other is the transition locus. It is found that the image number of the fold is exactly the average value of image numbers on two sides of the fold, while the image number of the cusp is equal to the smaller one. We also focus on the magnification patterns of the quadrupole (m = 2) lenses under the perturbations of m = 3, 4, and 5 mode components and found that one, two, and three butterfly or swallowtail singularities can be produced, respectively. With the increasing intensity of the high-order perturbations, the singularities grow up to bring sixfold image regions. If these perturbations are large enough to let two or three of the butterflies or swallowtails make contact, then eightfold or tenfold image regions can be produced as well. The possible astronomical applications are discussed.
Kohler, Susanna
2016-02-01
In KIC 9246715, two red-giant stars twins in nearly every way circle each other in a 171-day orbit. This binary pair may be a key to learning about masses and radii of stars with asteroseismology, the study of oscillations in the interiors of stars.Two Ways to MeasureIn order to understand a stars evolution, it is critical that we know its mass and radius. Unfortunately, these quantities are often difficult to pin down!One of the few cases in which we can directly measure stars masses and radii is in eclipsing binaries, wherein two stars eclipse each other as they orbit. If we have a well-sampled light curve for the binary, as well as radial velocities for both stars, then we can determine the stars complete orbital information, including their masses and radii.But there may be another way to obtain stellar mass and radius: asteroseismology. In asteroseismology, oscillations inside stars are used to characterize the stellar interiors. Conveniently, if a star with a convective envelope exhibits solar-like oscillations, these oscillations can be directly compared to those of the Sun. Mass and radius scaling relations which use the Sun as a benchmark and scale based on the stars temperature can then be used to derive the mass and radius of the star.Test Subjects from KeplerSolar-like oscillations from KIC 9246715 are shown in red across different resonant frequencies. The oscillations of a single red-giant star with similar properties are shown upside down in grey for reference. [Rawls et al. 2016]Of course, scaling relations are only useful if we can test them! A team of scientists including Meredith Rawls (New Mexico State University) has identified 18 red-giant eclipsing binaries in the Kepler field of view that also exhibit solar-like oscillations perfect for testing the scaling relations.In a recent study led by Rawls, the team analyzed the first of these binaries, KIC 9246715. Using the Kepler light curves in addition to radial velocity measurements from high
Giant intravesical calculus during pregnancy.
Escobar-del Barco, Laura; Rodriguez-Colorado, Silvia; Dueñas-Garcia, Omar Felipe; Avilez-Cevasco, Juan Carlos
2008-10-01
Urolithiasis is commonly found during pregnancy; but the presence of a giant vesical calculus during pregnancy is a very rare entity, associated with several potential obstetric complications. A 25-year-old primigravida at 25 weeks of gestational age was referred to our tertiary care unit because she presented a giant hyperechoic intravesical mass and inability to pass urine with suprapubic pain since 2 days. An open cystolithotomy revealed a huge intravesical calculus. The patient continued with her pregnancy until full term without adverse perinatal outcomes.
Giant fields in southwest Mexico
1981-07-20
According to Petroleos Mexicanos southeastern Mexico's Isthmus Saline basin holds five new giant fields - Tonala-El Burro, El Plan, Cinco Presidentes, Oraggio, and Magallanes - producing oil and gas from Tertiary sandstones. Numerous normal faults resulting from salt intrusion have given rise to multiple blocks, each with its own reservoir conditions. Previously discovered basins in the area include the Macuspana, which holds three giant gas- and condensate-producing fields: Jose Colomo, Chilapilla, and Hormiquero. The 3100-mi/sup 2/ Campeche marine platform, extending offshore nearby, contains the Cantarell complex, Mexico's most productive hydrocarbon province.
Spectrally resolved resonant propulsion of dielectric microspheres
Li, Yangcheng; Limberopoulos, Nicholaos I; Urbas, Augustine M; Astratov, Vasily N
2015-01-01
Use of resonant light forces opens up a unique approach to high-volume sorting of microspherical resonators with much higher uniformity of resonances compared to that in coupled-cavity structures obtained by the best semiconductor technologies. In this work, the spectral response of the propulsion forces exerted on polystyrene microspheres near tapered microfibers is directly observed. The measurements are based on the control of the detuning between the tunable laser and internal resonances in each sphere with accuracy higher than the width of the resonances. The measured spectral shape of the propulsion forces correlates well with the whispering-gallery mode resonances in the microspheres. The existence of a stable radial trap for the microspheres propelled along the taper is demonstrated. The giant force peaks observed for 20-{\\mu}m spheres are found to be in a good agreement with a model calculation demonstrating an efficient use of the light momentum for propelling the microspheres.
Secular resonances with Ceres and Vesta
Tsirvoulis, Georgios
2016-01-01
In this work we explore dynamical perturbations induced by the massive asteroids Ceres and Vesta on main-belt asteroids through secular resonances. First we determine the location of the linear secular resonances with Ceres and Vesta in the main belt, using a purely numerical technique. Then we use a set of numerical simulations of fictitious asteroids to investigate the importance of these secular resonances in the orbital evolution of main-belt asteroids. We found, evaluating the magnitude of the perturbations in the proper elements of the test particles, that in some cases the strength of these secular resonances is comparable to that of known non-linear secular resonances with the giant planets. Finally we explore the asteroid families that are crossed by the secular resonances we studied, and identified several cases where the latter seem to play an important role in their post-impact evolution.
Experimental and Theoretical Studies of Pressure Broadened Alkali-Metal Atom Resonance Lines
Shindo, F.; Zhu, C.; Kirby, K.; Babb, J. F.
2006-01-01
We are carrying out a joint theoretical and experimental research program to study the broadening of alkali atom resonance lines due to collisions with helium and molecular hydrogen for applications to spectroscopic studies of brown dwarfs and extrasolar giant planets.
Polarised bremsstrahlung nuclear resonance fluorescence set-up at the 15 MeV linac in Gent
Govaert, K.; Mondelaers, W.; Jacobs, E.; De Frenne, D.; Persyn, K.; Pommé, S.; Yoneama, M.-L.; Lindenstruth, S.; Huber, K.; Jung, A.; Starck, B.; Stock, R.; Wesselborg, C.; Heil, R.-D.; Kneissl, U.; Pitz, H. H.
1994-01-01
Nuclear resonance fluorescence experiments using unpolarised as well as off-axis linearly polarised bremsstrahlung represent an outstanding tool to determine in a completely model independent way transition probabilities, multipole orders and parities of electromagnetic transitions to bound states in nuclei. A new polarised bremsstrahlung facility has been constructed at the 15 MeV linac in Gent. The experimental arrangement is discussed and first results are presented.
Pygmy dipole resonance in 208Pb
Poltoratska, I; Tamii, A; Adachi, T; Bertulani, C A; Carter, J; Dozono, M; Fujita, H; Fujita, K; Fujita, Y; Hatanaka, K; Itoh, M; Kawabata, T; Kalmykov, Y; Krumbholz, A M; Litvinova, E; Matsubara, H; Nakanishi, K; Neveling, R; Okamura, H; Ong, H J; Özel-Tashenov, B; Ponomarev, V Yu; Richter, A; Rubio, B; Sakaguchi, H; Sakemi, Y; Sasamoto, Y; Shimbara, Y; Shimizu, Y; Smit, F D; Suzuki, T; Tameshige, Y; Wambach, J; Yosoi, M; Zenihiro, J
2012-01-01
Scattering of protons of several hundred MeV is a promising new spectroscopic tool for the study of electric dipole strength in nuclei. A case study of 208Pb shows that at very forward angles J^pi = 1- states are strongly populated via Coulomb excitation. A separation from nuclear excitation of other modes is achieved by a multipole decomposition analysis of the experimental cross sections based on theoretical angular distributions calculated within the quasiparticle-phonon model. The B(E1) transition strength distribution is extracted for excitation energies up to 9 MeV, i.e., in the region of the so-called pygmy dipole resonance (PDR). The Coulomb-nuclear interference shows sensitivity to the underlying structure of the E1 transitions, which allows for the first time an experimental extraction of the strength and energy centroid of the PDR.
Measurement of Inverse Pion Photoproduction at Energies Spanning the N(1440) Resonance
Shafi, A; Strakovsky, I I; Briscoe, W J; Nefkens, B M K; Allgower, C E; Arndt, R A; Bekrenev, V; Bennhold, C; Clajus, M; Comfort, J R; Craig, K; Grosnick, D P; Isenhower, D; Knecht, N; Koetke, D D; Kulbardis, A; Kozlenko, N; Kruglov, S; Lolos, G J; Lopatin, I; Manley, D M; Manweiler, R; Marusic, A; McDonald, S; Olmsted, J; Papandreou, Z; Peaslee, D; Phaisangittisakul, N; Price, J W; Ramírez, A F; Sadler, M; Spinka, H; Stanislaus, T D S; Starostin, A; Staudenmaier, H M; Supek, I; Tippens, W B; Workman, R L; Workman, and R.L.
2004-01-01
Differential cross sections for the process pi^- p -> gamma n have been measured at Brookhaven National Laboratory's Alternating Gradient Synchrotron with the Crystal Ball multiphoton spectrometer. Measurements were made at 18 pion momenta from 238 to 748 MeV/c, corresponding to E_gamma for the inverse reaction from 285 to 769 MeV. The data have been used to evaluate the gamma n multipoles in the vicinity of the N(1440) resonance. We compare our data and multipoles to previous determinations. A new three-parameter SAID fit yields 36 +/- 7 (GeV)^-1/2 X 10^-3 for the A^n_1/2 amplitude of the P_11.
Gokce Yildiran
2015-04-01
Conclusion: Giant lipomas of the hand are very rare and may cause compressions and other complications. Thus, they require a careful preoperative evaluation in order to make a proper differential diagnosis. [Hand Microsurg 2015; 4(1.000: 8-11
Schmid, Herman
2005-01-01
EU may appear to be a giant when it can act on behalf of a united Europe, but usually it is hampered by conflicting member state interests. The EU economic and administrative resources for foreign and trade policy are quite small (on level with one of its major member states) and the hopes in man...
The giant panda gut microbiome.
Wei, Fuwen; Wang, Xiao; Wu, Qi
2015-08-01
Giant pandas (Ailuropoda melanoleuca) are bamboo specialists that evolved from carnivores. Their gut microbiota probably aids in the digestion of cellulose and this is considered an example of gut microbiota adaptation to a bamboo diet. However, this issue remains unresolved and further functional and compositional studies are needed. Copyright © 2015 Elsevier Ltd. All rights reserved.
Brock, Raymond; Nichols, Sue
2007-01-01
"That giant is 750 miles of fiber optic cable that lassoes its three biggest research universities and Van Andel Institute to the future. Its mission: to uncover the nature of the Big Bang by connecton U.S. physicists to their huge experiment ATLAS in Geneva.." (4 pages)
Schmid, Herman
2005-01-01
EU may appear to be a giant when it can act on behalf of a united Europe, but usually it is hampered by conflicting member state interests. The EU economic and administrative resources for foreign and trade policy are quite small (on level with one of its major member states) and the hopes in man...
Cloud formation in giant planets
Helling, Christiane
2007-01-01
We calculate the formation of dust clouds in atmospheres of giant gas-planets. The chemical structure and the evolution of the grain size distribution in the dust cloud layer is discussed based on a consistent treatment of seed formation, growth/evaporation and gravitational settling. Future developments are shortly addressed.
Giant nontraumatic intradiploic arachnoid cyst in a young male*
Sharma, Rajesh; Gupta, Puneet; Mahajan, Manik; Sharma, Poonam; Gupta, Anchal; Khurana, Arti
2016-01-01
Intradiploic arachnoid cysts have scarcely been reported in the literature, most reported cases being secondary to trauma. Nontraumatic arachnoid cysts are quite rare and have been reported mostly in adults. Here, we report the case of a 16-year-old male presenting with a slowly growing mass in the occipital region and intermittent headaches. On the basis of the findings of X-rays, computed tomography scans, and magnetic resonance imaging scans of the head, the mass was diagnosed as a giant intradiploic arachnoid cyst. PMID:27818549
Face of the giant panda sign in Wilson disease
Sumit Chakraborty
2013-08-01
Full Text Available Wilson disease usually presents with neurologic or hepatic manifestations. Magnetic resonance imaging (MRI of the brain is very informative in diagnosiing of this disease, especially in patients with neurological features. High T2 signal intensity in the corpus striatum is the most commonly encountered MRI finding. The 'face of the giant panda' sign is seen on axial T2-weighted MRI, and results from abnormal signal intensities in the midbrain. Though uncommon, the sign is considered as the pathognomonic MRI sign of Wilson disease.
Giant non traumatic intradiploic arachnoid cyst in a young male
Sharma, Rajesh [Department of Radiodiagnosis and Imaging, ASCOMS Hospital, Sidhra, Jammu (India); Gupta, Puneet; Mahajan, Manik, E-mail: puneetgupta619@yahoo.com [Department of Radiodiagnosis and Imaging, Lady Hardinge Medical College, New Delhi (India); Sharma, Poonam [Department of Pathology, GMC, Jammu (India); Gupta, Anchal; Khurana, Arti [Department of Radiodiagnosis and Imaging, GMC, Jammu (J and K) (India)
2016-09-15
Intradiploic arachnoid cysts have scarcely been reported in the literature, most reported cases being secondary to trauma. Non traumatic arachnoid cysts are quite rare and have been reported mostly in adults. Here, we report the case of a 16-year-old male presenting with a slowly growing mass in the occipital region and intermittent headaches. On the basis of the findings of X-rays, computed tomography scans, and magnetic resonance imaging scans of the head, the mass was diagnosed as a giant intradiploic arachnoid cyst. Keywords: Arachnoid cysts; Cerebrospinal fluid; Headache/diagnosis. (author)
Bone Deformities as a Complication of Giant Thoracic Aortic Aneurysm.
Aslan, Ahmet; Kartal, Yiğitcan; Ayaz, Ercan; Aslan, Mine; Bulut, Safiye Sanem Dereli; Ağırbaşlı, Mehmet Ali; Oysu, Aslıhan Semiz
2017-07-01
The contained rupture of thoracic aortic aneurysm and related bone deformities is a rare condition. The diagnosis is critical due to potential and fatal complications. Radiologic evaluation is required to show the location, extension, and complications. Herein we present the X-ray radiography, ultrasonography, computed tomography, and magnetic resonance images of a giant dissected and contained rupture of the thoracic aortic aneurysm. The aneurysm destructed the adjacent vertebrae and rib, resulting in compression of dural sac and spinal cord, and obliteration of the neural foramina. Our case demonstrates a gigantic expansion of an aneurysm (14 cm) with chronic skeletal complications.
Giant Optomechanical Enhancement in the Presence of Gain and Loss
Jing, H; Lv, Xin-You; Zhang, Jing; Nori, F
2014-01-01
The parity-time-symmetric structure was experimentally accessible very recently in coupled optical resonators with which, for normal or non-PT-symmetric cases, a phonon laser device had also been realized. Here we study cavity optomechanics of this system now with tunable gain-loss ratio. We find that nonlinear behaviors emerge for cavity-photon populations around balanced point, resulting giant enhancement of both optical pressure and phonon-lasing action. Potential applications range from enhancing mechanical cooling to designing highly-efficient phonon-laser amplifier.
Giant nontraumatic intradiploic arachnoid cyst in a young male
Rajesh Sharma
Full Text Available Abstract Intradiploic arachnoid cysts have scarcely been reported in the literature, most reported cases being secondary to trauma. Nontraumatic arachnoid cysts are quite rare and have been reported mostly in adults. Here, we report the case of a 16-year-old male presenting with a slowly growing mass in the occipital region and intermittent headaches. On the basis of the findings of X-rays, computed tomography scans, and magnetic resonance imaging scans of the head, the mass was diagnosed as a giant intradiploic arachnoid cyst.
Giant-resonance studies with radioactive beams : Perspectives
Harakeh, M.N.
First-generation radioactive ion-beam facilities have already been in operation for some time. Advanced facilities that will deliver high-intensity radioactive nuclear beams ranging in energy from below the Coulomb barrier to up to several hundred MeV per nucleon (MeV/u) are either starting
Isoscalar Giant Resonances of 120Sn in the Quasiparticle RRPA
CAOLi-gang; MAZhong-yu
2003-01-01
In present work we have formulated the quasiparticle relativistic random phase approximation (QRRPA) model based on the relativistic mean field ground state in the response function formalism. The pairing correlations are taken into account in the BCS approximation with a constant pairing gap extracted from the experimental binding energies of neighboring nuclei.
Giant Dipole Resonance decay of hot rotating 88Mo
Ciemała M.
2014-03-01
Full Text Available An experiment focusing on study of the properties of hot rotating compound nucleus of 88Mo was performed in LNL Legnaro using 48Ti beam at energies of 300 and 600 MeV on 40Ca target. The compound nucleus was produced at the temperatures of 3 and 4.5 MeV, with angular momentum distribution with lmax > 60 ħ (i.e. exceeding the crtical angular momentum for fission. High-energy gamma rays, measured in coincidence with evaporation residues and alpha particles, were analyzed with the statistical model. The GDR parameters were obtained from the best fit to the data, which allowed investigating an evolution of the GDR width up to high temperatures.
Giant Dipole Resonance decay of hot rotating 88Mo
Ciemała, M.; Kmiecik, M.; Maj, A.; Kravchuk, V. L.; Gramegna, F.; Barlini, S.; Casini, G.; Camera, F.
2014-03-01
An experiment focusing on study of the properties of hot rotating compound nucleus of 88Mo was performed in LNL Legnaro using 48Ti beam at energies of 300 and 600 MeV on 40Ca target. The compound nucleus was produced at the temperatures of 3 and 4.5 MeV, with angular momentum distribution with lmax > 60 ħ (i.e. exceeding the crtical angular momentum for fission). High-energy gamma rays, measured in coincidence with evaporation residues and alpha particles, were analyzed with the statistical model. The GDR parameters were obtained from the best fit to the data, which allowed investigating an evolution of the GDR width up to high temperatures.
Giant magnetic quadrupole resonance studied with 180 deg. electron scattering
Neumann-Cosel, P V
1999-01-01
The nuclei sup 4 sup 8 Ca and sup 9 sup 0 Zr were investigated in 180 deg. high-resolution inelastic electron scattering for momentum transfers q approx =0.35-0.8 fm sup - sup 1. Complete M2 strength distributions could be extracted in both nuclei up to excitation energies of about 15 MeV utilizing a fluctuation analysis technique. Second-RPA calculations successfully describe the experimentally observed strong fragmentation of the M2 mode. The quenching of the spin part is found to be comparable to the M1 case, contrary to previous claims suggesting a stronger reduction. A quantitative reproduction of the data requires the presence of appreciable orbital strength which can be interpreted as a torsional elastic vibration (the so-called twist mode).
On the Nature and Timing of Giant Planet Migration in the Solar System
Agnor, Craig B.
2016-05-01
Giant planet migration is a natural outcome of gravitational scattering and planet formation processes (Fernandez & Ip 1984). There is compelling evidence that the solar system's giant planets experienced large-scale migration involving close approaches between planets as well as smooth radial migration via planetesimal scattering. Aspects of giant planet migration have been invoked to explain many features of the outer solar system including the resonant structure of the Kuiper Belt (e.g., Malhotra 1993, Levison et al. 2008), the eccentricities of Jupiter and Saturn (Tsiganis et al. 2005, Morbidelli et al. 2009), the capture of Jupiter's Trojan companions (Morbidelli et al. 2005) and the capture of irregular planetary satellites (e.g., Nesvorny et al. 2007) to name a few. If this migration epoch occurred after the formation of the inner planets, then it may also explain the so-called lunar Late Heavy Bombardment (Gomes et al. 2005). This scenario necessarily requires coeval terrestrial and migrating giant planets. Recent N-body integrations exploring this issue have shown that giant planet migration may excite the terrestrial system via nodal and apsidal secular resonances (e.g., Brasser et al. 2013), may drive the terrestrial planets to crossing orbits (Kaib & Chambers 2016) or alternatively leave the inner solar system in a state closely resembling the observed one (Roig et al. 2016). The factors accounting for the large range of outcomes remain unclear. Using linear secular models and N-body simulations I am identifying and characterising the principal aspects of giant planet migration that excite the terrestrial planets' orbits. I will present these results and discuss how they inform the nature and timing of giant planet migration in the solar system.
Stability and Formation of the Resonant System HD 73526
Sándor, Z; Klagyivik, P
2007-01-01
Based on radial velocity measurements it has been found recently that the two giant planets detected around the star HD 73526 are in 2:1 resonance. However, as our numerical integration shows, the derived orbital data for this system result in chaotic behavior of the giant planets, which is uncommon among the resonant extrasolar planetary systems. We intend to present regular (non-chaotic) orbital solutions for the giant planets in the system HD 73526 and offer formation scenarios based on combining planetary migration and sudden perturbative effects such as planet-planet scattering or rapid dispersal of the protoplanetary disk. A comparison with the already studied resonant system HD 128311, exhibiting similar behavior, is also done. The new sets of orbital solutions have been derived by the Systemic Console (www.oklo.org). The stability of these solutions has been investigated by the Relative Lyapunov indicator, while the migration and scattering effects are studied by gravitational N-body simulations apply...
Multilevel fast multipole algorithm for elastic wave scattering by large three-dimensional objects
Tong, Mei Song; Chew, Weng Cho
2009-02-01
Multilevel fast multipole algorithm (MLFMA) is developed for solving elastic wave scattering by large three-dimensional (3D) objects. Since the governing set of boundary integral equations (BIE) for the problem includes both compressional and shear waves with different wave numbers in one medium, the double-tree structure for each medium is used in the MLFMA implementation. When both the object and surrounding media are elastic, four wave numbers in total and thus four FMA trees are involved. We employ Nyström method to discretize the BIE and generate the corresponding matrix equation. The MLFMA is used to accelerate the solution process by reducing the complexity of matrix-vector product from O(N2) to O(NlogN) in iterative solvers. The multiple-tree structure differs from the single-tree frame in electromagnetics (EM) and acoustics, and greatly complicates the MLFMA implementation due to the different definitions for well-separated groups in different FMA trees. Our Nyström method has made use of the cancellation of leading terms in the series expansion of integral kernels to handle hyper singularities in near terms. This feature is kept in the MLFMA by seeking the common near patches in different FMA trees and treating the involved near terms synergistically. Due to the high cost of the multiple-tree structure, our numerical examples show that we can only solve the elastic wave scattering problems with 0.3-0.4 millions of unknowns on our Dell Precision 690 workstation using one core.
Nuclear photonics at ultra-high counting rates and higher multipole excitations
Thirolf, P. G.; Habs, D.; Filipescu, D.; Gernhaeuser, R.; Guenther, M. M.; Jentschel, M.; Marginean, N.; Pietralla, N. [Fakultaet f. Physik, Ludwig-Maximilians-Universitaet Muenchen, Garching (Germany); Fakultaet f. Physik, Ludwig-Maximilians-Universitaet Muenchen, Garching, Germany and Max-Planck-Institute f. Quantum Optics, Garching (Germany); IFIN-HH, Bucharest-Magurele (Romania); Physik Department E12,Technische Universitaet Muenchen, Garching (Germany); Max-Planck-Institute f. Quantum Optics, Garching (Germany); Institut Laue-Langevin, Grenoble (France); Physik Department E12,Technische Universitaet Muenchen, Garching (Germany); Institut f. Kernphysik, Technische Universitaet Darmstadt (Germany)
2012-07-09
Next-generation {gamma} beams from laser Compton-backscattering facilities like ELI-NP (Bucharest)] or MEGa-Ray (Livermore) will drastically exceed the photon flux presently available at existing facilities, reaching or even exceeding 10{sup 13}{gamma}/sec. The beam structure as presently foreseen for MEGa-Ray and ELI-NP builds upon a structure of macro-pulses ({approx}120 Hz) for the electron beam, accelerated with X-band technology at 11.5 GHz, resulting in a micro structure of 87 ps distance between the electron pulses acting as mirrors for a counterpropagating intense laser. In total each 8.3 ms a {gamma} pulse series with a duration of about 100 ns will impinge on the target, resulting in an instantaneous photon flux of about 10{sup 18}{gamma}/s, thus introducing major challenges in view of pile-up. Novel {gamma} optics will be applied to monochromatize the {gamma} beam to ultimately {Delta}E/E{approx}10{sup -6}. Thus level-selective spectroscopy of higher multipole excitations will become accessible with good contrast for the first time. Fast responding {gamma} detectors, e.g. based on advanced scintillator technology (e.g. LaBr{sub 3}(Ce)) allow for measurements with count rates as high as 10{sup 6}-10{sup 7}{gamma}/s without significant drop of performance. Data handling adapted to the beam conditions could be performed by fast digitizing electronics, able to sample data traces during the micro-pulse duration, while the subsequent macro-pulse gap of ca. 8 ms leaves ample time for data readout. A ball of LaBr{sub 3} detectors with digital readout appears to best suited for this novel type of nuclear photonics at ultra-high counting rates.
Lin, Dejun
2015-09-01
Accurate representation of intermolecular forces has been the central task of classical atomic simulations, known as molecular mechanics. Recent advancements in molecular mechanics models have put forward the explicit representation of permanent and/or induced electric multipole (EMP) moments. The formulas developed so far to calculate EMP interactions tend to have complicated expressions, especially in Cartesian coordinates, which can only be applied to a specific kernel potential function. For example, one needs to develop a new formula each time a new kernel function is encountered. The complication of these formalisms arises from an intriguing and yet obscured mathematical relation between the kernel functions and the gradient operators. Here, I uncover this relation via rigorous derivation and find that the formula to calculate EMP interactions is basically invariant to the potential kernel functions as long as they are of the form f(r), i.e., any Green's function that depends on inter-particle distance. I provide an algorithm for efficient evaluation of EMP interaction energies, forces, and torques for any kernel f(r) up to any arbitrary rank of EMP moments in Cartesian coordinates. The working equations of this algorithm are essentially the same for any kernel f(r). Recently, a few recursive algorithms were proposed to calculate EMP interactions. Depending on the kernel functions, the algorithm here is about 4-16 times faster than these algorithms in terms of the required number of floating point operations and is much more memory efficient. I show that it is even faster than a theoretically ideal recursion scheme, i.e., one that requires 1 floating point multiplication and 1 addition per recursion step. This algorithm has a compact vector-based expression that is optimal for computer programming. The Cartesian nature of this algorithm makes it fit easily into modern molecular simulation packages as compared with spherical coordinate-based algorithms. A
Ibeid, Huda
2016-03-04
Exascale systems are predicted to have approximately 1 billion cores, assuming gigahertz cores. Limitations on affordable network topologies for distributed memory systems of such massive scale bring new challenges to the currently dominant parallel programing model. Currently, there are many efforts to evaluate the hardware and software bottlenecks of exascale designs. It is therefore of interest to model application performance and to understand what changes need to be made to ensure extrapolated scalability. The fast multipole method (FMM) was originally developed for accelerating N-body problems in astrophysics and molecular dynamics but has recently been extended to a wider range of problems. Its high arithmetic intensity combined with its linear complexity and asynchronous communication patterns make it a promising algorithm for exascale systems. In this paper, we discuss the challenges for FMM on current parallel computers and future exascale architectures, with a focus on internode communication. We focus on the communication part only; the efficiency of the computational kernels are beyond the scope of the present study. We develop a performance model that considers the communication patterns of the FMM and observe a good match between our model and the actual communication time on four high-performance computing (HPC) systems, when latency, bandwidth, network topology, and multicore penalties are all taken into account. To our knowledge, this is the first formal characterization of internode communication in FMM that validates the model against actual measurements of communication time. The ultimate communication model is predictive in an absolute sense; however, on complex systems, this objective is often out of reach or of a difficulty out of proportion to its benefit when there exists a simpler model that is inexpensive and sufficient to guide coding decisions leading to improved scaling. The current model provides such guidance.