Sample records for magnetic-field-induced quadrupolar ordering

  1. Magnetic field induced ordering and phase diagram in underdoped LSCO

    NASA Astrophysics Data System (ADS)

    Hall, Jesse; Rõõm, Toomas; Nagel, Urmas; Hüvonen, Dan; Hawthorne, D.; Wakimoto, S.; Zhang, H.; Hwang, Jungseek; Komiya, Seiki; Timusk, Thomas

    2015-03-01

    The existence of ordered phases in superconducting cuprates has come under intense scrutiny with the revelation of charge-ordering near the superconducting transition in YBCO. Previous results demonstrating the existence of exotic ordered phases, including the existence of stripe order, and the richness of the magnetic-field/doping/temperature phase diagram, suggest that the underdoped region of the phase diagram may contain a wealth of information that has yet to be revealed. We turn our attention to La2-xSrxCuO4 on the boundary of superconductivity by studying the far-infrared optical properties of three single crystals with x=0.05, 0.06, and 0.07; the first is non-superconducting, the others have transition temperatures of 6 K and 12 K respectively. By applying a magnetic field up to 17 T we are able to suppress superconductivity where it exists and compare the field-induced normal state to that induced by temperature or by doping. By studying the optical conductivity of these materials and the changes in the spectral weight with temperature and field, we can gain insight into the field induced ordered states of underdoped cuprate superconductors.

  2. Antiferroquadrupole order and magnetic field induced octupole in CeB6

    NASA Astrophysics Data System (ADS)

    Matsumura, Takeshi; Yonemura, Takumi; Kunimori, Keisuke; Sera, Masafumi; Iga, Fumitoshi; Nagao, Tatsuya; Igarashi, Jun-ichi

    2012-05-01

    We have studied the antiferroquadrupole ordered phase of CeB6 in magnetic fields by resonant x-ray diffraction. By analyzing the significant change in the energy spectrum on reversing the field direction along [1¯10], we have deduced field dependencies of the antiferro components of magnetic dipole, electric quadrupole, and magnetic octupole moments which are simultaneously induced in the Ce 4f orbital with a propagation vector ((1)/(2),(1)/(2),(1)/(2)). The data treatments are based on theoretically calculated spectral functions. The existence of the field-induced octupole is also concluded for other field directions. We also show direct evidence for the formation of a linear-combination-type antiferroquadrupole order parameter in magnetic fields, which is expressed as and changes continuously with the field direction (?,?,?). A possibility of observing the quadrupolar fluctuation is also pointed out.

  3. Magnetic field induced third order susceptibility of third order harmonic generation in a ZnMgSe strained quantum well

    SciTech Connect

    Mark, J. Abraham Hudson, E-mail: a.john.peter@gmail.com; Peter, A. John, E-mail: a.john.peter@gmail.com [Dept. of Physics, SSM Institute of Engineering and Technology, Dindigul-624002 (India)

    2014-04-24

    Third order susceptibility of third order harmonic generation is investigated in a Zn{sub 0.1}Mg{sub 0.9}Se/Zn{sub 0.8}Mg{sub 0.2}Se/Zn{sub 0.1}Mg{sub 0.9}Se quantum well in the presence of magnetic field strength. The confinement potential is considered as the addition of energy offsets of the conduction band (or valence band) and the strain-induced potential in our calculations. The material dependent effective mass is followed throughout the computation because it has a high influence on the electron energy levels in low dimensional semiconductor systems.

  4. Magnetic field induced dynamical chaos

    SciTech Connect

    Ray, Somrita; Baura, Alendu; Bag, Bidhan Chandra, E-mail: bidhanchandra.bag@visva-bharati.ac.in [Department of Chemistry, Visva-Bharati, Santiniketan 731 235 (India)

    2013-12-15

    In this article, we have studied the dynamics of a particle having charge in the presence of a magnetic field. The motion of the particle is confined in the x–y plane under a two dimensional nonlinear potential. We have shown that constant magnetic field induced dynamical chaos is possible even for a force which is derived from a simple potential. For a given strength of the magnetic field, initial position, and velocity of the particle, the dynamics may be regular, but it may become chaotic when the field is time dependent. Chaotic dynamics is very often if the field is time dependent. Origin of chaos has been explored using the Hamiltonian function of the dynamics in terms of action and angle variables. Applicability of the present study has been discussed with a few examples.

  5. Theory of inelastic light scattering in spin-1 systems: Resonant regimes and detection of quadrupolar order

    NASA Astrophysics Data System (ADS)

    Michaud, F.; Vernay, F.; Mila, F.

    2011-11-01

    Motivated by the lack of an obvious spectroscopic probe to investigate nonconventional order such as quadrupolar orders in spin S>(1)/(2) systems, we present a theoretical approach to inelastic light scattering for spin-1 quantum magnets in the context of a two-band Hubbard model. In contrast to the S=(1)/(2) case, where the only type of local excited state is a doubly occupied state of energy U, several local excited states with occupation up to four electrons are present. As a consequence, we show that two distinct resonating scattering regimes can be accessed depending on the incident photon energy. For ??in?U, the standard Loudon-Fleury operator remains the leading term of the expansion as in the spin-(1)/(2) case. For ??in?4U, a second resonant regime is found with a leading term that takes the form of a biquadratic coupling ˜(Si·Sj)2. Consequences for the Raman spectra of S=1 magnets with magnetic or quadrupolar order are discussed. Raman scattering appears to be a powerful probe of quadrupolar order.

  6. Quadrupolar ordering of phospholipid molecules in narrow necks of phospholipid vesicles

    Microsoft Academic Search

    Veronika Kralj-Iglic; Blaz Babnik; Dorit R. Gauger; Sylvio May; Aleš Igli?

    2006-01-01

    Shapes of phospholipid vesicles that involve narrow neck(s) were studied theoretically. It is taken into account that phospholipid\\u000a molecules are intrinsically anisotropic with respect to the membrane normal and that they exhibit quadrupolar orientational\\u000a ordering according to the difference between the local principal membrane curvatures. Direct interactions between oriented\\u000a molecules were considered within a linear approximation of the energy coupling

  7. Separated quadrupolar field experiment.

    PubMed

    Kumar, Rajeev; Ling, Wen; Schoefberger, Wolfgang; Jerschow, Alexej

    2005-02-01

    We describe an NMR experiment that produces spectra correlating the first-order quadrupolar spectrum and the central transition spectrum of half-integer quadrupolar spins, allowing one to separate the quadrupolar parameters in overlapping spectra under both static and magic-angle-spinning conditions. Promising fields of applications include situations where the sample cannot easily be rotated, or where it cannot be rotated at the magic angle. PMID:15649747

  8. Magnetoelastic domains and magnetic field-induced strains in ferromagnetic shape memory alloys by phase-field simulation

    E-print Network

    Shu, Yi-Chung

    Magnetoelastic domains and magnetic field-induced strains in ferromagnetic shape memory alloys; accepted 10 April 2008; published online 29 April 2008 Magnetoelastic domains in ferromagnetic shape memory ferroelastic and ferromagnetic ordering simultaneously,1 and this magnetoelastic coupling makes it possible

  9. Tetrahedratic mesophases, chiral order, and helical domains induced by quadrupolar and octupolar interactions.

    PubMed

    Trojanowski, Karol; Paj?k, Grzegorz; Longa, Lech; Wydro, Thomas

    2012-07-01

    We present an exhaustive account of phases and phase transitions that can be stabilized in the recently introduced generalized Lebwohl-Lasher model with quadrupolar and octupolar microscopic interactions [L. Longa, G. Paj?k, and T. Wydro, Phys. Rev. E 79, 040701(R) (2009)]. A complete mean-field analysis of the model, along with Monte Carlo simulations allows us to identify four distinct classes of the phase diagrams with a number of multicritical points where, in addition to the standard uniaxial and biaxial nematic phases, the other nematic like phases are stabilized. These involve, among the others, tetrahedratic (T), nematic tetrahedratic (N(T)), and chiral nematic tetrahedratic (N(T)(*)) phases of global T(d), D(2d), and D(2) symmetry, respectively. Molecular order parameters and correlation functions in these phases are determined. We conclude with generalizations of the model that give a simple molecular interpretation of macroscopic regions with opposite optical activity (ambidextrous chirality), observed, e.g., in bent-core systems. An estimate of the helical pitch in the N(T)(*) phase is also given. PMID:23005434

  10. Mössbauer Spectroscopy of the Magnetic-Field-Induced Ferroelectric Phase of CuFeO2

    NASA Astrophysics Data System (ADS)

    Nakamura, Shin; Kobayashi, Yasuhiro; Kitao, Shinji; Seto, Makoto; Fuwa, Akio; Terada, Noriki

    2015-02-01

    57Fe Mössbauer spectroscopy in an applied magnetic field has been conducted on single crystals of CuFeO2 and CuFe0.965Ga0.035O2 in order to investigate magnetic-field-induced ferroelectric states. The Mössbauer spectra observed under a magnetic field change significantly, corresponding to magnetic-field-induced phase transitions. In the ferroelectric incommensurate (FEIC) phase (7 < Hex < 13 T), the spectrum can be explained by a model with spins distributed at approximately 20, 95, and 160° from the c-axis in the (110) plane. This spin configuration resembles the "complex noncollinear spin configuration (CNC)" model proposed theoretically. In the FEIC phase, the isomer shift is larger, while the quadrupole splitting and average hyperfine field are smaller than those in the collinear four sublattice (4SL, 0 < Hex < 7 T) and five sublattice (5SL, Hex > 13 T) phases. In addition, a noticeable change in the hyperfine field is observed with varying magnetic field. We consider that these changes indicate the change in the electronic state of the Fe3+ ion, possibly modified by a spin-orbit interaction.

  11. Magnetic-Field Induced Quantum Phase Transitions in Triangular-Lattice Antiferromagnets

    E-print Network

    McQuade, D. Tyler

    Magnetic-Field Induced Quantum Phase Transitions in Triangular-Lattice Antiferromagnets T Ono1, H Department of Physics, Smith College, Northampton, Massachusetts 01063, USA 5 National High Magnetic Field a spatially anisotropic triangular lattice, successive magnetic-field induced quantum phase transitions

  12. Optical gyrotropy in quadrupolar Kondo systems

    NASA Astrophysics Data System (ADS)

    Lee, SungBin; Paramekanti, Arun; Kim, Yong Baek

    2015-01-01

    Recent experiments point to a variety of intermetallic systems which exhibit exotic quadrupolar orders driven by the Kondo coupling between conduction electrons and localized quadrupolar degrees of freedom. Using a Luttinger k .p Hamiltonian for the conduction electrons, we study the impact of such quadrupolar order on their energies and wave functions. We discover that such quadrupolar orders can induce a nontrivial Berry curvature for the conduction electron bands, leading to a nonvanishing optical gyrotropic effect. We estimate the magnitude of the gyrotropic response in a candidate quadrupolar material, PrPb3, and discuss the resulting Faraday rotation in thin films.

  13. Magnetic-field-induced ferroelectric polarization reversal in the multiferroic Ge(1-x)Mn(x)Te semiconductor.

    PubMed

    Przybyli?ska, H; Springholz, G; Lechner, R T; Hassan, M; Wegscheider, M; Jantsch, W; Bauer, G

    2014-01-31

    Ge(1-x)Mn(x)Te is shown to be a multiferroic semiconductor, exhibiting both ferromagnetic and ferroelectric properties. By ferromagnetic resonance we demonstrate that both types of order are coupled to each other. As a result, magnetic-field-induced ferroelectric polarization reversal is achieved. Switching of the spontaneous electric dipole moment is monitored by changes in the magnetocrystalline anisotropy. This also reveals that the ferroelectric polarization reversal is accompanied by a reorientation of the hard and easy magnetization axes. By tuning the GeMnTe composition, the interplay between ferromagnetism and ferroelectricity can be controlled. PMID:24580486

  14. Path-integral Monte Carlo study of asymmetric quantum quadrupolar rotors with fourth-order propagators

    NASA Astrophysics Data System (ADS)

    Park, Sungjin; Shin, Hyeondeok; Kwon, Yongkyung

    2012-08-01

    The recently-proposed fourth-order propagator based on the multi-product expansion has been applied to path-integral Monte Carlo calculations for asymmetric quantum quadruploar rotors fixed at face-centered cubic lattice sites. The rotors are observed to undergo an orientational orderdisorder phase transition at a low temperature when the electric quadrupole-quadrupole interaction is strong enough. At intermediate interaction strength, a further decrease of temperature after the first transition to the ordered phase results in a reentrant transition back to the disordered phase. The theoretical phase diagram of these asymmetric rotors determined by using fourth-order path-integral Monte Carlo calculations is found to be in good quantitative agreement with the experimental one for solid hydrogen deuteride. This leads us to conclude that the fourth-order propagator can be effectively implemented for an accurate path-integral Monte Carlo calculation of a quantum many-body system with rotational degrees of freedom.

  15. Powder MAS NMR lineshapes of quadrupolar nuclei in the presence of second-order quadrupole interaction.

    PubMed

    Ajoy, G; Ramakrishna, J; Bahçeli, S; Klinowski, J

    2000-07-01

    We derive a complete analytical solution for the powder magic angle spinning (MAS) nuclear magnetic resonance (NMR) lineshape in the presence of second-order quadrupole interaction, considering a radiofrequency (rf) pulse of finite width, a finite MAS frequency, and a non-zero asymmetry parameter. (Ix) is calculated using two approaches. The first applies time-dependent perturbation theory in the presence of the rf pulse and stationary perturbation theory (SPT) in its absence. The second is based on the Magnus expansion of the density matrix in the interaction representation during the pulse and SPT in its absence. We solve the problem in the laboratory frame using the properties of the Fourier transform and spin operators. Diagonalisation is not required. Both approaches agree well with each other under all conditions and also with the transition probability approach for the central transition. The Magnus expansion exists at all times and the effect of the non-secular terms is negligible. We describe an analytical method of averaging (Ix) over the Euler angles and simulate the 11B MAS NMR lineshapes for crystalline and vitreous B2O3. A critical analysis is given of all earlier calculations of the MAS NMR lineshape. PMID:10928635

  16. Pulsed magnetic field-induced twin boundary motion on Ni-Mn-Ga

    E-print Network

    Marioni, Miguel Augusto, 1971-

    2003-01-01

    The magnetic field-induced strain (ferromagnetic shape memory effect - FSME) in Ni-Mn-Ga was first reported in 1996 by Ullakko et al. Since then, up to 6% FSME in single-crystal tetragonal-Ni-Mn-Ga samples has been observed ...

  17. Magnetic-field-induced crystallographic texture enhancement in cold-deformed FePt nanostructured magnets

    E-print Network

    Garmestani, Hamid

    Magnetic-field-induced crystallographic texture enhancement in cold-deformed FePt nanostructured magnets B. Z. Cuia and K. Han National High Magnetic Field Laboratory, Florida State University Grenoble, France H. J. Schneider-Muntau National High Magnetic Field Laboratory, Florida State University

  18. Biomaterials 28 (2007) 11051114 Flow and magnetic field induced collagen alignment

    E-print Network

    Kaufman, Laura

    2007-01-01

    with this technique. It is also demonstrated that alignment can be attained in both plain and cell-bearing gelsBiomaterials 28 (2007) 1105­1114 Flow and magnetic field induced collagen alignment Cheng Guo technique to align thin collagen gels is presented. This technique requires only collagen solution, surface

  19. Magnetic Field Induced Quantum Phase Transition in Multiferroic Vanadium Spinels

    NASA Astrophysics Data System (ADS)

    Mun, E.-D.; Chern, G.-W.; Pardo, V.; Rivadulla, F.; Sinclair, R.; Zhou, H. D.; Zapf, V. S.; Batista, C. D.

    2014-03-01

    Vanadium spinels with the formula AV2O4 (A = Cd, Mg, Zn, etc) show strong magnetic frustration due to a structure of corner-sharing tetrahedra. A tetragonal structural distortion and an ``up up down down'' magnetic ordering along diagonal chains result at low temperatures, which breaks spatial-inversion symmetry. CdV2O4 is insulating enough that this magnetic order produces ferroelectricity. Here we present data on CdV2O4 and MgV2O4, showing a field-induced quantum phase transition near 40 Tesla, which is a very small energy scale compared to the dominant magnetic exchange interactions. This transition suppresses ferroelectricity and produces a magnetization jump. We show that this transition can be explained by a model that includes spin-orbit coupling effects, and also a trigonal structural distortion at zero and applied magnetic fields.

  20. Magnetic-field-induced vertigo: a theoretical and experimental investigation.

    PubMed

    Glover, P M; Cavin, I; Qian, W; Bowtell, R; Gowland, P A

    2007-07-01

    Vertigo-like sensations or apparent perception of movement are reported by some subjects and operators in and around high field whole body magnetic resonance body scanners. Induced currents (which modulate the firing rate of the vestibular hair cell), magneto-hydrodynamics (MDH), and tissue magnetic susceptibility differences have all been proposed as possible mechanisms for this effect. In this article, we examine the theory underlying each of these mechanisms and explore resulting predictions. Experimental evidence is summarised in the following findings: 30% of subjects display a postural sway response at a field-gradient product of 1 T(2)m(-1); a determining factor for experience of vertigo is the total unipolar integrated field change over a period greater than 1 s; the perception of dizziness is not necessarily related to a high value of the rate of change of magnetic field; eight of ten subjects reported sensations ranging from mild to severe when exposed to a magnetic field change of the order of 4.7 T in 1.9 s; no subjects reported any response when exposed to 50 ms pulses of dB/dt of 2 Ts(-1) amplitude. The experimental evidence supports the hypothesis that magnetic-field related vertigo results from both magnetic susceptibility differences between vestibular organs and surrounding fluid, and induced currents acting on the vestibular hair cells. Both mechanisms are consistent with theoretical predictions. PMID:17427890

  1. Superconductivity, magnetic order, and quadrupolar order in the filled skutterudite system Pr 1 ? x Nd x Os 4 Sb 12

    DOE PAGESBeta

    Ho, P.-C.; Yanagisawa, T.; Yuhasz, W. M.; Dooraghi, A. A.; Robinson, C. C.; Butch, N. P.; Baumbach, R. E.; Maple, M. B.

    2011-01-01

    Superconductivity, magnetic order, and the high field ordered phase have been investigated in the filled skutterudite system Pr1-xNdxOs?Sb?? as a function of composition x in magnetic fields up to 9 T and at temperatures between 50 mK and 10 K. Electrical resistivity measurements indicate that the high field ordered phase, which has been identified with antiferroquadruoplar order, persists to x ~ 0.5. The superconducting critical temperature Tc of PrOs?Sb?? is depressed linearly with Nd concentration to x ~ 0.55, whereas the Curie temperature TFM of NdOs?Sb?? is depressed linearly with Pr composition to (1-x) ~ 0.45. In the superconducting region, the upper critical field Hc2(x,0) is depressed quadratically with x in the range 0 c2(x,0) appears to be a result of pair breaking caused by the applied magnetic field and the exchange field associated with the polarization of the Nd magnetic moments in the superconducting state. From magnetic susceptibility measurements, the correlations between the Nd moments in the superconducting state appear to change from ferromagnetic in the range 0.3 ? x ? 0.6 to antiferromagnetic in the range 0 c2(x,0) with x.

  2. Restatement of order parameters in biomembranes: calculation of C-C bond order parameters from C-D quadrupolar splittings.

    PubMed Central

    Douliez, J P; Léonard, A; Dufourc, E J

    1995-01-01

    An expression for the C-C bond order parameter, SCC, of membrane hydrocarbon chains has been derived from the observed C-D bond order parameters. It allows calculation of the probability of each of the C-C bond rotamers and, consequently, the number of gauche defects per chain as well as their projected average length onto the bilayer normal, thus affording the calculation of accurate hydrophobic bilayer thicknesses. The effect of temperature has been studied on dilauroyl-, dimyristoyl-, and dipalmitoylphosphatidylcholine (DLPC, DMPC, DPPC) membranes, as has the effect of cholesterol on DMPC. The salient results are as follows: 1) an odd-even effect is observed for the SCC versus carbon position, k, whose amplitude increases with temperature; 2) calculation of SCC, from nonequivalent deuterons on the sn-2 chain of lipids, SCC2, leads to negative values, indicating the tendency for the C1-C2 bond to be oriented parallel to the bilayer surface; this bond becomes more parallel to the surface as the temperature increases or when cholesterol is added; 3) calculation on the sn-2 chain length can be performed from C1 to Cn, where n is the number of carbon atoms in the chain, and leads to 10.4, 12.2, and 13.8 A for DLPC, DMPC, and DPPC close to the transition temperature, TC, of each of the systems and to 9.4, 10.9, and 12.6 for T-TC = 30-40 degrees C, respectively; 4) separation of intra- and intermolecular motions allows quantitation of the number of gauche defects per chain, which is equal to 1.9, 2.7, and 3.5 for DLPC, DMPC, and DPPC near TC and to 2.7, 3.5, and 4.4 at T-TC = 30-40 degrees C, respectively. Finally, the validity of our model is discussed and compared with previously published models. PMID:7612816

  3. Magnetic field induced quantum phase transitions in the two-impurity Anderson model

    SciTech Connect

    Zhu, Lujun [Los Alamos National Laboratory; Zhu, Jian - Xin [Los Alamos National Laboratory

    2010-11-17

    In the two-impurity Anderson model, the inter-impurity spin exchange interaction favors a spin singlet state between two impurities leading to the localization of quasiparticles. We show that a local uniform magnetic field can delocalize the quasiparticies to restore the Kondo resonance. This transition is found to be continuous, accompanied by not only the divergence of the staggered (anti ferromagnetic) susceptibility, but also the divergence of the uniform spin susceptibility. This implies that the magnetic field induced quantum phase transitions in Kondo systems are in favor of the local critical type.

  4. Magnetic-field-induced ferroelectric polarization reversal in magnetoelectric composites revealed by piezoresponse force microscopy

    NASA Astrophysics Data System (ADS)

    Miao, Hongchen; Zhou, Xilong; Dong, Shuxiang; Luo, Haosu; Li, Faxin

    2014-07-01

    Controlling electric polarization (or magnetization) in multiferroic materials with external magnetic fields (or electric fields) is very important for fundamental physics and spintronic devices. Although there has been some progress on magnetic-field-induced polarization reversal in single-phase multiferroics, such behavior has so far never been realized in composites. Here we show that it is possible to reverse ferroelectric polarization using magnetic fields in a bilayer Terfenol-D/PMN-33%PT composite. We realized this by ferroelectric domain imaging using piezoresponse force microscopy (PFM) under applied magnetic field loading. The internal electric field caused by the magnetoelectric (ME) effect in the PMN-PT crystal is considered as the driving force for the 180° polarization switching, and its existence is verified by switching spectroscopy PFM testing under a series of external magnetic fields. A quantitative method is further suggested to estimate the local ME coefficient based on the switching spectroscopy PFM testing results.

  5. Magnetic-Field-Induced Transitions of Many-Electron States in Quantum Dots

    NASA Astrophysics Data System (ADS)

    Natori, Akiko; Nakamura, Daisuke

    1999-01-01

    The many-electron eigenstates of anisotropic parabolic quantumdots with cylindrical symmetry are investigatedusing anunrestricted Hartree-Fock method, in a magneticfield parallel to the cylindrical z-axis.The many-electron eigenstates are assigned by two quantumnumbers, Lzand Sz, the z-components of the total orbital angular momentum and thetotal spin, respectively.The many-electron ground states exhibit sequential transitionsvia three stages with increasing magnetic field. At the transition magnetic fields, the ground state energy crosses that of thefirst-excited state with different values of (Lz, Sz)and they replace each other. The phase diagram of theground state is obtained in a space of the magnetic field and theelectron number. The phase diagram is greatly affected by the lateralextent of quantum dots, but the effect of the vertical extent is small for quasi-two-dimensional quantum dots.In these magnetic field induced transitions, theHartree interactionplays a dominant role.

  6. Magnetic-field-induced optical anisotropy in ferrofluids: A time-dependent light-scattering investigation

    NASA Astrophysics Data System (ADS)

    Rablau, Corneliu; Vaishnava, Prem; Sudakar, Chandran; Tackett, Ronald; Lawes, Gavin; Naik, Ratna

    2008-11-01

    We report an experimental investigation of time dependent anisotropic light scattering by an aqueous suspension of tetramethyl ammonium hydroxide coated Fe3O4 nanoparticles (˜6nm) under the ON-OFF transient of an external dc magnetic field. The study employs the synchronized recording and measurement of the two magnetic-field-induced light-scattering patterns produced by two identical orthogonal He-Ne laser beams passing through the ferrofluid sample and propagating parallel and perpendicular to the applied field, respectively. From these patterns, we extract the time dependence of the induced optical anisotropy, which provides a measure of the characteristic time scale and kinematic response for field-induced structure formation in the sample. We propose that the time evolution of the scattering patterns, which is very fast at short times and significantly slower at long times, can be explained using a model based on a two-stage chain formation and coarsening processes.

  7. Magnetic-field-induced ferroelectric polarization reversal in magnetoelectric composites revealed by piezoresponse force microscopy.

    PubMed

    Miao, Hongchen; Zhou, Xilong; Dong, Shuxiang; Luo, Haosu; Li, Faxin

    2014-08-01

    Controlling electric polarization (or magnetization) in multiferroic materials with external magnetic fields (or electric fields) is very important for fundamental physics and spintronic devices. Although there has been some progress on magnetic-field-induced polarization reversal in single-phase multiferroics, such behavior has so far never been realized in composites. Here we show that it is possible to reverse ferroelectric polarization using magnetic fields in a bilayer Terfenol-D/PMN-33%PT composite. We realized this by ferroelectric domain imaging using piezoresponse force microscopy (PFM) under applied magnetic field loading. The internal electric field caused by the magnetoelectric (ME) effect in the PMN-PT crystal is considered as the driving force for the 180° polarization switching, and its existence is verified by switching spectroscopy PFM testing under a series of external magnetic fields. A quantitative method is further suggested to estimate the local ME coefficient based on the switching spectroscopy PFM testing results. PMID:24953042

  8. Magnetic-field induced semimetal in topological crystalline insulator thin films

    NASA Astrophysics Data System (ADS)

    Ezawa, Motohiko

    2015-06-01

    We investigate electromagnetic properties of a topological crystalline insulator (TCI) thin film under external electromagnetic fields. The TCI thin film is a topological insulator indexed by the mirror-Chern number. It is demonstrated that the gap closes together with the emergence of a pair of gapless cones carrying opposite chirarities by applying in-plane magnetic field. A pair of gapless points have opposite vortex numbers. This is a reminiscence of a pair of Weyl cones in 3D Weyl semimetal. We thus present an a magnetic-field induced semimetal-semiconductor transition in 2D material. This is a giant-magnetoresistance, where resistivity is controlled by magnetic field. Perpendicular electric field is found to shift the gapless points and also renormalize the Fermi velocity in the direction of the in-plane magnetic field.

  9. Magnetic-Field-Induced insulator-conductor transition in SU(2) quenched lattice gauge theory

    E-print Network

    P. V. Buividovich; M. N. Chernodub; D. E. Kharzeev; T. Kalaydzhyan; E. V. Luschevskaya; M. I. Polikarpov

    2010-09-30

    We study the correlator of two vector currents in quenched $SU\\lr{2}$ lattice gauge theory with a chirally invariant lattice Dirac operator with a constant external magnetic field. It is found that in the confinement phase the correlator of the components of the current parallel to the magnetic field decays much slower than in the absence of a magnetic field, while for other components the correlation length slightly decreases. We apply the maximal entropy method to extract the corresponding spectral function. In the limit of zero frequency this spectral function yields the electric conductivity of the quenched theory. We find that in the confinement phase the external magnetic field induces nonzero electric conductivity along the direction of the field, transforming the system from an insulator into an anisotropic conductor. In the deconfinement phase the conductivity does not exhibit any sizable dependence on the magnetic field.

  10. Muon Spin Relaxation Studies of Magnetic-Field-Induced Effects in High-Tc Superconductors A. T. Savici,1

    E-print Network

    Weston, Ken

    Muon Spin Relaxation Studies of Magnetic-Field-Induced Effects in High-Tc Superconductors A. T; published 4 October 2005) Muon spin relaxation measurements in high transverse magnetic fields ( k ^c, derived from the muon spin relaxation rate, exhibits a divergent behavior towards T 25 K. No field

  11. Magnetic-field-induced diameter-selective synthesis of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Su, Yanjie; Zhang, Yaozhong; Wei, Hao; Zhang, Liling; Zhao, Jiang; Yang, Zhi; Zhang, Yafei

    2012-02-01

    We report a facile and scalable approach to synthesize single-walled carbon nanotubes (SWNTs) with selected diameter distribution by applying a magnetic field perpendicular to the electric field in the arc plasma region. It is found that this magnetic field-induced diameter-selectivity strategy enables the control of the SWNTs with different diameter distributions in different regions, and the diameter-selective efficiency could be enhanced by modifying the direction of magnetic field. Our results indicate that the motions of the catalysts with different particle sizes, positive carbon ions and electrons are significantly influenced by the magnetic field and electromagnetic force, resulting in the different nucleation and growth processes of SWNTs due to the collective interactions between the magnetic field and arc plasma. This approach would enable a viable route towards the synthesis of SWNTs with desired diameter through the tuning of arc parameters in the arc discharge process.We report a facile and scalable approach to synthesize single-walled carbon nanotubes (SWNTs) with selected diameter distribution by applying a magnetic field perpendicular to the electric field in the arc plasma region. It is found that this magnetic field-induced diameter-selectivity strategy enables the control of the SWNTs with different diameter distributions in different regions, and the diameter-selective efficiency could be enhanced by modifying the direction of magnetic field. Our results indicate that the motions of the catalysts with different particle sizes, positive carbon ions and electrons are significantly influenced by the magnetic field and electromagnetic force, resulting in the different nucleation and growth processes of SWNTs due to the collective interactions between the magnetic field and arc plasma. This approach would enable a viable route towards the synthesis of SWNTs with desired diameter through the tuning of arc parameters in the arc discharge process. Electronic supplementary information (ESI) available: Schematic diagram of SWNT sampling points, peak areas of S22 and M11 and relative ratios of S/M. See DOI: 10.1039/c2nr11783e

  12. Magnetic-field-induced recovery strain in polycrystalline Ni-Mn-Ga foam

    NASA Astrophysics Data System (ADS)

    Chmielus, Markus; Witherspoon, Cassie; Wimpory, Robert C.; Paulke, Andreas; Hilger, André; Zhang, Xuexi; Dunand, David C.; Müllner, Peter

    2010-12-01

    Recently, we have shown that a polycrystalline Ni-Mn-Ga magnetic shape-memory alloy, when containing two populations of pore sizes, shows very high magnetic-field-induced strain of up to 8.7%. Here, this double-porosity sample is imaged by x-ray microtomography, showing a homogenous distribution of both pore populations. The orientation of six large grains—four with 10M and two with 14M structure—is identified with neutron diffraction. In situ magnetomechanical experiments with a rotating magnetic field demonstrate that strain incompatibilities between misoriented grains are effectively screened by the pores which also stop the propagation of microcracks. During uniaxial compression performed with an orthogonal magnetic bias field, a strain as high as 1% is recovered on unloading by twinning, which is much larger than the elastic value of <0.1% measured without field. At the same time, repeated loading and unloading results in a reduction in the yield stress, which is a training effect similar to that in single crystals.

  13. High Magnetic Field-Induced Birefringence in Lyotropic Chromonic Liquid Crystals

    NASA Astrophysics Data System (ADS)

    Ostapenko, T.; Nastishin, Yu.; Gleeson, J. T.; Sprunt, S. N.; Lavrentovich, O. D.; Collings, P. J.

    2009-03-01

    We studied the effect of magnetic-field induced birefringence of a 14% solution of disodium cromoglycate (DSCG) in water at temperatures above the nematic-isotropic coexistence region. According to Landau-deGennes mean field theory, we expect to find a linear relationship between the inverse of the induced birefringence, ?n, and the quantity (T-T*), where T* is the stability limit of the isotropic phase. Using the 31 T resistive magnet at the National High Magnetic Field Laboratory, we observed that, as we increase the temperature above the coexistence region, we deviate from this linear dependence. Our data shows that ?n goes to zero, whereas Landau-deGennes predicts that ?n should decrease asymptotically. This may be due to the lack of isodesmic aggregate formation at a finite temperature above the coexistence region.Supported by NSF (DMR-0710544 and DMR-0606160). Work performed at NHMFL, supported by NSF cooperative agreements DMR-0084173, the State of Florida and the DOE.

  14. Phenomenology of giant magnetic-field-induced strain in ferromagnetic shape-memory materials (invited)

    SciTech Connect

    O'Handley, R. C. [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)] [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Murray, S. J. [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)] [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Marioni, M. [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)] [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Nembach, H. [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)] [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Allen, S. M. [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)] [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2000-05-01

    Ferromagnetic shape-memory alloys have recently emerged as a new class of active materials showing very large magnetic-field-induced extensional strains. Recently, a single crystal of a tetragonally distorted Heusler alloy in the NiMnGa system has shown a 5% shear strain at room temperature in a field of 4 kOe. The magnetic and crystallographic aspects of the twin-boundary motion responsible for this effect are described. Ferromagnetic shape-memory alloys strain by virtue of the motion of the boundaries separating adjacent twin variants. The twin-boundary motion is driven by the Zeeman energy difference between the adjacent twins due to their nearly orthogonal magnetic easy axes and large magnetocrystalline anisotropy. The twin boundary constitutes a nearly 90 degree sign domain wall. Essentially, twin-boundary motion shorts out the more difficult magnetization rotation process. The field and stress dependence of the strain are reasonably well accounted for by minimization of a simple free energy expression including Zeeman energy, magnetic anisotropy energy, internal elastic energy, and external stress. Models indicate the limits to the magnitude of the field-induced strain and point to the material parameters that make the effect possible. The field-induced strain in ferromagnetic shape-memory alloys is contrasted with the more familiar phenomenon of magnetostriction. (c) 2000 American Institute of Physics.

  15. Tailor-made nanocontainers for combined magnetic-field-induced release and MRI.

    PubMed

    Bannwarth, Markus B; Ebert, Sandro; Lauck, Maximilian; Ziener, Ulrich; Tomcin, Stephanie; Jakob, Gerhard; Münnemann, Kerstin; Mailänder, Volker; Musyanovych, Anna; Landfester, Katharina

    2014-09-01

    The synthesis of a novel nanocapsule-based carrier system is described, possessing a triggered release in remote-controlled fashion upon application of an external magnetic field in combination with the possibility to use the capsules as contrast agents for magnetic resonance imaging (MRI). Therefore, polymeric nanocontainers containing a high amount of superparamagnetic MnFe2 O4 nanoparticles and a thermo-degradable shell are fabricated via a miniemulsion route. The process allows the facile encapsulation of hydrophilic compounds, as demonstrated for a model dye. Release of the encapsulated dye is achieved upon application of an external alternating magnetic field. While the magnetic nanoparticles here act as heat generators to stimulate the decomposition of the shell and subsequently a release of the payload, they additionally enable the use of the nanocapsules as imaging agents for MRI. Due to the encapsulated magnetic nanoparticles, the nanocapsules possess high r2 relaxivity values of 96-120?Hz?mmol(-1) , which makes them suitable for MRI. In toxicity experiments, the nanocapsules show no cell toxicity up to fairly high concentrations (600?µg?mL(-1) ). Due to their dual-functionality, the nanocapsules possess high potential as nanocarriers with combined magnetic-field-induced release capability and as contrast agents for MRI. PMID:24811570

  16. Isotropic-Cholesteric Co-Existence and Magnetic Field-Induced Isotropic-Nematic Transition of Filamentous Bacteriophage FD in Aqueous Suspension.

    NASA Astrophysics Data System (ADS)

    Tang, Jianxin

    1995-01-01

    Isotropic to liquid crystalline phase transition for a lyotropic suspension of geometrically asymmetric macromolecules occurs to a wild class of synthetic polymers and biopolymers. Although in decades statistical mechanical theories have been developed to predict the thermodynamic conditions and the properties of such transition, quantitative comparison with theory has been compounded with complications such as charge, shape, polydispersity in size, and additional interactions with the solvent and among the macromolecules themselves. We chose the aqueous suspension of the filamentous bacteriophage fd as a model system to study the isotropic to liquid crystalline transition. The co-existence concentrations, as a function of ionic strength, were measured directly by spectrophotometry. Our data confirm quantitatively the predictions of a statistical mechanic treatment first described by Onsager, modified to include the effects of charge and flexibility of rodlike particles. We have also extended a previous study of the pretransitional angular correlations in the isotropic solutions of fd through the measurement of the magnetic-field-induced birefringence, i.e. the measurement of the Cotton-Mouton constant. At several ionic strengths the magnetic-field-induced birefringence, which is proportional to the number of particles in a correlation volume N_{rm corr}, was measured for fd concentrations spanning the entire isotropic region. From this data the limiting concentration of stability (spinodal) of the isotropic phase is obtained. A theoretical expression for the magnetic birefringence of persistent polymers was derived and agreed well with the data with the exception that N_{rm corr} at the isotropic to liquid crystal transition was smaller than predicted. In the proximity of the highest possible isotropic concentration, that is the isotropic in co-existence with anisotropic, we studied the effect of a high magnetic field. A first order field-induced isotropic-nematic phase transition was observed with intriguing dynamics. This phase transition was probed by the measurement of magnetic birefringence, and by direct observation using a self-designed, tube polarizing microscope which fits in a two-inch bore of a 20 T magnet. Therefore, we were able to watch the rapid, cooperative alignment of the particles and the subsequent spinodal decomposition in the unstable region of the phase diagram, as well as the late stage nucleation in the process of the phase separation. The experimentally determined phase diagram closely resembles what the theory predicts. At last, we also measured the temperature dependence of co-existence concentrations and the magnetic field-induced birefringence at several concentrations in the isotropic phase. We attribute such dependence solely to the variation of the particle flexibility, and present a consistent treatment. This additional work demonstrates a useful application in the general study of persistent polymers.

  17. Magnetic field-induced phase transformation in NiMnCoIn magnetic shape memory alloys - a new actuation mechanism with large work output.

    SciTech Connect

    Karaca, H. E.; Karaman, I.; Basaran, B.; Ren, Y.; Chumlyakov, Y. I.; Maier, H. J.; X-Ray Science Division; Texsas A& M Univ.; Univ. of Kentucky; Siberian Physical-Technical Inst.; Univ. of Paderborn

    2009-04-09

    Magnetic shape memory alloys (MSMAs) have recently been developed into a new class of functional materials that are capable of magnetic-field-induced actuation, mechanical sensing, magnetic refrigeration, and energy harvesting. In the present work, the magnetic field-induced martensitic phase transformation (FIPT) in Ni{sub 45}Mn{sub 36.5}Co{sub 5}In{sub 13.5} MSMA single crystals is characterized as a new actuation mechanism with potential to result in ultra-high actuation work outputs. The effects of the applied magnetic field on the transformation temperatures, magnetization, and superelastic response are investigated. The magnetic work output of NiMnCoIn alloys is determined to be more than 1 MJ m{sup -3} per Tesla, which is one order of magnitude higher than that of the most well-known MSMAs, i.e., NiMnGa alloys. In addition, the work output of NiMnCoIn alloys is orientation independent, potentially surpassing the need for single crystals, and not limited by a saturation magnetic field, as opposed to NiMnGa MSMAs. Experimental and theoretical transformation strains and magnetostress levels are determined as a function of crystal orientation. It is found that [111]-oriented crystals can demonstrate a magnetostress level of 140 MPa T{sup -1} with 1.2% axial strain under compression. These field-induced stress and strain levels are significantly higher than those from existing piezoelectric and magnetostrictive actuators. A thermodynamical framework is introduced to comprehend the magnetic energy contributions during FIPT. The present work reveals that the magnetic FIPT mechanism is promising for magnetic actuation applications and provides new opportunities for applications requiring high actuation work-outputs with relatively large actuation frequencies. One potential issue is the requirement for relatively high critical magnetic fields and field intervals (1.5-3 T) for the onset of FIPT and for reversible FIPT, respectively.

  18. Magnetic-field-induced DNA strand breaks in brain cells of the rat.

    PubMed Central

    Lai, Henry; Singh, Narendra P

    2004-01-01

    In previous research, we found that rats acutely (2 hr) exposed to a 60-Hz sinusoidal magnetic field at intensities of 0.1-0.5 millitesla (mT) showed increases in DNA single- and double-strand breaks in their brain cells. Further research showed that these effects could be blocked by pretreating the rats with the free radical scavengers melatonin and N-tert-butyl-alpha-phenylnitrone, suggesting the involvement of free radicals. In the present study, effects of magnetic field exposure on brain cell DNA in the rat were further investigated. Exposure to a 60-Hz magnetic field at 0.01 mT for 24 hr caused a significant increase in DNA single- and double-strand breaks. Prolonging the exposure to 48 hr caused a larger increase. This indicates that the effect is cumulative. In addition, treatment with Trolox (a vitamin E analog) or 7-nitroindazole (a nitric oxide synthase inhibitor) blocked magnetic-field-induced DNA strand breaks. These data further support a role of free radicals on the effects of magnetic fields. Treatment with the iron chelator deferiprone also blocked the effects of magnetic fields on brain cell DNA, suggesting the involvement of iron. Acute magnetic field exposure increased apoptosis and necrosis of brain cells in the rat. We hypothesize that exposure to a 60-Hz magnetic field initiates an iron-mediated process (e.g., the Fenton reaction) that increases free radical formation in brain cells, leading to DNA strand breaks and cell death. This hypothesis could have an important implication for the possible health effects associated with exposure to extremely low-frequency magnetic fields in the public and occupational environments. PMID:15121512

  19. Dynamic-angle spinning and double rotation of quadrupolar nuclei

    SciTech Connect

    Mueller, K.T. (Lawrence Berkeley Lab., CA (United States) California Univ., Berkeley, CA (United States). Dept. of Chemistry)

    1991-07-01

    Nuclear magnetic resonance (NMR) spectroscopy of quadrupolar nuclei is complicated by the coupling of the electric quadrupole moment of the nucleus to local variations in the electric field. The quadrupolar interaction is a useful source of information about local molecular structure in solids, but it tends to broaden resonance lines causing crowding and overlap in NMR spectra. Magic- angle spinning, which is routinely used to produce high resolution spectra of spin-{1/2} nuclei like carbon-13 and silicon-29, is incapable of fully narrowing resonances from quadrupolar nuclei when anisotropic second-order quadrupolar interactions are present. Two new sample-spinning techniques are introduced here that completely average the second-order quadrupolar coupling. Narrow resonance lines are obtained and individual resonances from distinct nuclear sites are identified. In dynamic-angle spinning (DAS) a rotor containing a powdered sample is reoriented between discrete angles with respect to high magnetic field. Evolution under anisotropic interactions at the different angles cancels, leaving only the isotropic evolution of the spin system. In the second technique, double rotation (DOR), a small rotor spins within a larger rotor so that the sample traces out a complicated trajectory in space. The relative orientation of the rotors and the orientation of the larger rotor within the magnetic field are selected to average both first- and second-order anisotropic broadening. The theory of quadrupolar interactions, coherent averaging theory, and motional narrowing by sample reorientation are reviewed with emphasis on the chemical shift anisotropy and second-order quadrupolar interactions experienced by half-odd integer spin quadrupolar nuclei. The DAS and DOR techniques are introduced and illustrated with application to common quadrupolar systems such as sodium-23 and oxygen-17 nuclei in solids.

  20. Multiple-Rotor-Cycle QPASS Pulse Sequences: Separation of Quadrupolar Spinning Sidebands with an Application to 139La NMR

    Microsoft Academic Search

    David J. Aurentz; Frederick G. Vogt; Karl T. Mueller; Alan J. Benesi

    1999-01-01

    The quadrupolar phase-adjusted spinning sidebands (QPASS) pulse sequence has been recently demonstrated as a useful method for obtaining quadrupolar parameters with magic-angle spinning NMR. The sequence separates spinning sidebands by order in a two-dimensional experiment. A sheared projection of the 2D spectrum effectively yields the infinite spinning rate second-order quadrupolar powder pattern, which can be analyzed to determine quadrupolar coupling

  1. Multiple-Rotor-Cycle QPASS Pulse Sequences: Separation of Quadrupolar Spinning Sidebands with an Application to ^139La NMR

    Microsoft Academic Search

    David J. Aurentz; Frederick G. Vogt; Karl T. Mueller; Alan J. Benesi

    1999-01-01

    The quadrupolar phase-adjusted spinning sidebands (QPASS) pulse sequence has been recently demonstrated as a useful method for obtaining quadrupolar parameters with magic-angle spinning NMR. The sequence separates spinning sidebands by order in a two-dimensional experiment. A sheared projection of the 2D spectrum effectively yields the infinite spinning rate second-order quadrupolar powder pattern, which can be analyzed to determine quadrupolar coupling

  2. Angular Dependence of Quantum Oscillations, Magnetoresistance, and Magnetic Field Induced Phase Transitions in Quasi-Two - Organic Molecular Conductors.

    NASA Astrophysics Data System (ADS)

    Athas, Gregory Joseph

    The Fermi surface (FS) topology of the Quasi-Two -Dimensional (Q2D) organic conductor family alpha -(ET)_2MHg(SCN)_4 (alpha- bis(ethylenedithio) tetrathiafulvalene -M (=potassium, rubidium, thallium, or ammonium)-mercury -thiocyanate) has been systematically studied in order to understand the different electronic ground-states and associated mechanisms in these isostructural materials. The ammonium salt undergoes a superconducting transition at ~1 K, while the remaining three salts enter a unique Low Temperature State (LTS) below a characteristic temperature T_{DW}. Here a Peierls-like transition into either a Spin or Charge Density Wave (SDW or CDW) has been proposed to describe the LTS. Unlike the insulating state expected for a SDW or CDW, the FS reconstructs at T_ {DW},<=aving the LTS metallic. This is due to the presence of two bands: the open orbit band is unstable at T_{DW} and becomes gapped, but the closed orbit band remains in a reconstructed topology. Therefore magneto-quantum oscillations are accessible in the LTS, and a thorough study of the magnetoresistance and Shubnikov-de Haas oscillations as a function of magnetic field strength and orientation has been applied. From these measurements we have determined the topological Fermi surface changes that occur in the formation of the LTS, mechanisms involving magnetotransport in the LTS, and the nature of the LTS (SDW vs. CDW). The experimental and theoretical results of this work suggest that in the LTS the Fermi surface has hexagonal symmetry, and exhibits magnetic breakdown effects which are strongly influenced by magnetic field orientation. At special angles magnetic breakdown is suppressed, revealing dramatic changes in the dc and quantum oscillatory magnetotransport properties. A model, distinct from that proposed by others, is presented to describe the behavior. Additionally, the LTS state can be suppressed completely by an isotropic magnetic field (>23 tesla), which is most consistent with the destruction of a CDW ground state in high magnetic field. Finally, the strong hysteresis associated with the magnetic field induced DW to metal transition, along with the observation of quantum oscillations from both the metallic and LTS structure lead us to propose a domain scheme for magnetic fields near the hysteretic region.

  3. Convection-driven quadrupolar dynamos in rotating spherical shells.

    PubMed

    Grote, E; Busse, F H; Tilgner, A

    1999-11-01

    It is found that for Taylor numbers of the order 10(8) quadrupolar dynamos aligned with the axis of rotation are preferred in comparison with dipolar dynamos. This preference holds for a range of Prandtl numbers P and magnetic Prandtl numbers P(m) in the neighborhood of unity. The main time-dependent feature of the quadrupolar dynamos are polward traveling waves. PMID:11970447

  4. The derivation of effective spin Hamiltonians and the origin of the magnetic field induced transition in orthormbic La sub 2 CuO sub 4

    SciTech Connect

    Coffey, D.

    1991-01-01

    La{sub 2}CuO{sub 4} undergoes a magnetic field induced transition in a field of {approx}5.7 Tesla at low temperatures. The origin of this transition is the Dzyaloshinskii-Moriya interaction which is present in effective spin Hamiltonians for systems of sufficiently low symmetry, and, which leads to weak ferromagnetism in the CuO planes in La{sub 2}CuO{sub 4}. It is shown here how this interaction depends on symmetry and how its form changes with structural phase transitions which occur in compounds closely related to La{sub 2}CuO{sub 4}. These different forms of the interaction lead to different properties in magnetic fields. I also discuss how the approach presented here of determining an effective spin Hamiltonian from symmetry is related to the determination of terms in the free expansion close to a second order phase transition. It is pointed out that the present approach may be extended to itinerant systems and 1 take UPt{sub 3} as an example. 28 refs., 4 figs.

  5. Four-component Hartree-Fock calculations of magnetic-field induced circular birefringence--Faraday effect--in noble gases and dihalogens.

    PubMed

    Ekström, Ulf; Norman, Patrick; Rizzo, Antonio

    2005-02-15

    The effects of relativity on the magnetic-field induced circular birefringence, or Faraday effect, in He, Ne, Ar, Xe, Rn, F2, Cl2, Br2, and I2 have been determined at the four-component Hartree-Fock level of theory. A measure of the birefringence is given by the Verdet constant, which is a third-order molecular property and thus relates to quadratic response functions. A fully analytical nonlinear polarization propagator approach is employed. The results are gauge invariant as a consequence of the spatial symmetries in the molecular systems. The calculations include electronic as well as vibrational contributions to the property. Comparison with experiment is made for He, Ne, Ar, Xe, and Cl2, and, apart from neon, the theoretical values of the Verdet constant are within 10% of the experimental ones. The inclusion of nonrelativistically spin-forbidden excitations in the propagator parametrization has significant effects on the dispersion in general, but such effects are in the general case largely explained by the use of a resonant-divergent propagator theory. In the present work we do, however, observe noticeable relativistic corrections to the Verdet constant in the off-resonant regions for systems with light elements (F2 and Cl2), and nonrelativistic results for the Verdet constant of Br2 are in error by 25% in the low-frequency region. PMID:15743246

  6. Magnetic-field-induced superconductivity and superfluidity of W and Z bosons: in tandem transport and kaleidoscopic vortex states

    E-print Network

    Chernodub, M N; Verschelde, Henri

    2013-01-01

    We show that in a background of a sufficiently strong magnetic field the electroweak sector of the quantum vacuum exhibits superconducting and, simultaneously, superfluid properties due to magnetic-field-induced condensation of, respectively, W and Z bosons. The phase transition to the "tandem" superconductor--superfluid phase - which is weakly sensitive to the Higgs sector of the standard model - occurs at the critical magnetic field of 10^{20} Tesla. The superconductor-superfluid phase has anisotropic transport properties as both charged and neutral superflows may propagate only along the magnetic field axis. The ground state possesses an unusual "kaleidoscopic" structure made of a hexagonal lattice of superfluid vortices superimposed on a triangular lattice of superconductor vortices. A weak electric field will induce both superconducting and, unexpectedly, superfluid flows.

  7. Magnetic-field-induced superconductivity and superfluidity of W and Z bosons: in tandem transport and kaleidoscopic vortex states

    E-print Network

    M. N. Chernodub; Jos Van Doorsselaere; Henri Verschelde

    2013-09-09

    We show that in a background of a sufficiently strong magnetic field the electroweak sector of the quantum vacuum exhibits superconducting and, unexpectedly, superfluid properties due to the magnetic-field-induced condensation of, respectively, W and Z bosons. The phase transition to the "tandem" superconductor-superfluid phase -- which is weakly sensitive to the Higgs sector of the standard model -- occurs at the critical magnetic field of 10^{20} T. The superconductor-superfluid phase of the electroweak vacuum has anisotropic transport properties as both charged and neutral superflows may propagate only along the magnetic field axis. The ground state possesses an unusual "kaleidoscopic" structure made of a hexagonal lattice of superfluid vortices superimposed on a triangular lattice of superconductor vortices.

  8. Magnetic torque studies on FFLO phase in magnetic-field-induced organic superconductor ?-(BETS)2FeCl4

    NASA Astrophysics Data System (ADS)

    Uji, S.; Kodama, K.; Sugii, K.; Terashima, T.; Takahide, Y.; Kurita, N.; Tsuchiya, S.; Kimata, M.; Kobayashi, A.; Zhou, B.; Kobayashi, H.

    2012-05-01

    Magnetic torque measurements have been carried out for two-dimensional magnetic-field-induced organic superconductor ?-(BETS)2FeCl4, where BETS stands for bis(ethylenedithio)tetraselenafulvalene, to investigate the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) phase. The in-plane upper critical field of the field-induced-superconducting phase steeply decreases with decreasing temperature below 2.2 K. The in-plane field dependence of the diamagnetic susceptibility shows a significant decrease below 25 T at low temperatures, showing that magnetic fluxes are less excluded from the sample. These results show the presence of the FFLO phase with the tricritical point between the FFLO, homogeneous superconducting, and paramagnetic metallic phases at 2.2 K and 23 T. The stability of the FFLO phase is also investigated as a function of the magnetic field angle and compared with theories.

  9. Boundary conditions for quadrupolar metamaterials

    NASA Astrophysics Data System (ADS)

    Silveirinha, Mário G.

    2014-08-01

    One of the long-standing problems in effective medium theories is using the knowledge of the bulk material response to predict the behavior of the electromagnetic fields at the material boundaries. Here, using a first principles approach, we derive the boundary conditions satisfied by the macroscopic fields at interfaces between reciprocal metamaterials with a quadrupolar-type response. Our analysis reveals that in addition to the usual Maxwellian-type boundary conditions for the tangential fields, in general—to ensure the conservation of the power flow and Lorentz reciprocity—it is necessary to enforce an additional boundary condition (ABC) at an interface between a quadrupolar material and a standard dielectric. It is shown that the ABC is related to the emergence of an additional wave in the bulk quadrupolar medium.

  10. Magnetic field-induced phase transformation and variant reorientation in Ni2MnGa and NiMnCoIn magnetic shape memory alloys 

    E-print Network

    Karaca, Haluk Ersin

    2009-05-15

    The purpose of this work is to reveal the governing mechanisms responsible for the magnetic field-induced i) martensite reorientation in Ni2MnGa single crystals, ii) stress-assisted phase transformation in Ni2MnGa single ...

  11. Magnetic-field-induced odd-frequency superconductivity in s-wave superconductors

    NASA Astrophysics Data System (ADS)

    Matsumoto, Masashige; Koga, Mikito; Kusunose, Hiroaki

    2013-08-01

    The wavefunction of the Cooper pair of the conventional BCS state is characterized by an evenparity (s-wave) spin-singlet state. An external magnetic field is well known to modify the wavefunction of the Cooper pair and to break the conventional BCS superconducting state. We find that the wavefunction of the modified Cooper pair contains a spin-triplet component with s-wave orbital symmetry. While the spin-triplet s-wave Cooper pair is forbidden owing to the fermion property, it is permitted in the generalized theoretical framework containing an odd-frequency dependence of the order parameter. We investigate this point on the basis of the self-consistent calculation in the Eliashberg theory and find that the odd-frequency order parameter coexists with the evenfrequency one. We also report how the physical properties are affected by the induced odd-frequency superconducting order parameter.

  12. Magnetic-field-induced Heisenberg to XY crossover in a quasi-2D quantum antiferromagnet

    NASA Astrophysics Data System (ADS)

    Fortune, N. A.; Hannahs, S. T.; Landee, C. P.; Turnbull, M. M.; Xiao, F.

    2014-12-01

    The magnetic-field-dependent ordering temperature of the quasi-2D quantum Heisenberg antiferromagnet (QHAF) Cu(pz)2(ClO4)2 was determined by calorimetric measurement in applied dc fields up to 33 tesla. The magnetic phase diagram shows a round maximum at 5.95 K and 17.5 T (at ? 1/3 of its saturation field), a 40 percent enhancement of the ordering temperature above the zero field value of 4.25 K. The enhancement and reentrance are consistent with predictions of a field-induced Heisenberg to XY crossover behavior for an ideal 2D QHAF system.

  13. Magnetic field-induced martensitic transformation and large magnetoresistance in NiCoMnSb alloys

    E-print Network

    Zexian, Cao

    in Ni50-xCoxMn39Sb11 alloys. The partial substitution of Co for Ni has turned the antiferromagnetically aligned Mn moments in the starting material Ni50Mn39Sb11 into a ferromagnetic ordering, raising transformation, and the transformation temperature T0=259 K could be lowered by 35 K under a field of 10 T. Also

  14. Magnetic-field-induced Mott transition in a quasi-two-dimensional organic conductor.

    PubMed

    Kagawa, F; Itou, T; Miyagawa, K; Kanoda, K

    2004-09-17

    We investigated the effect of magnetic field on the highly correlated metal near the Mott transition in the quasi-two-dimensional layered organic conductor, kappa-(BEDT-TTF)(2)Cu[N(CN)(2)]Cl, by the resistance measurements under control of temperature, pressure, and magnetic field. It was demonstrated that the marginal metallic phase near the Mott transition is susceptible to the field-induced localization transition of the first order, as was predicted theoretically. The thermodynamic consideration of the present results gives a conceptual pressure-field phase diagram of the Mott transition at low temperatures. PMID:15447299

  15. Magnetic field-induced direct–indirect crossover in AlxGa1?xAs

    NASA Astrophysics Data System (ADS)

    Alberi, Kirstin; Mialitsin, Aleksej V.; Fluegel, Brian; Crooker, Scott A.; Reno, John L.; Mascarenhas, Angelo

    2014-11-01

    We induce a direct–indirect band gap crossover in a single AlxGa1?xAs sample by using high magnetic fields. A reduction in the photoluminescence (PL) peak energy and onset of an asymmetric peak lineshape at magnetic fields >38 T result from a competition between the radiative recombination lifetime and the carrier migration time as the alloy becomes indirect. By analyzing the progression of the PL lineshape as the magnetic field is increased we show that the crossover is an alloy disorder-broadened, first-order phase transition.

  16. Magnetic-field-induced phase transitions in the quasi-one-dimensional organic conductor HMTSF-TCNQ

    NASA Astrophysics Data System (ADS)

    Murata, K.; Fukumoto, Y.; Yokogawa, K.; Takaoka, R.; Kang, W.; Brooks, J. S.; Graf, D.; Yoshino, H.; Sasaki, T.; Kato, R.

    2014-04-01

    Motivated by an interest to see if the field-induced (FI) phase in the charge-density wave (CDW) system is similar to the field-induced-SDW (FISDW) in (TMTSF)2X, (TMTSF: tetramethyltetraselenafulvalene), we examined the magnetic-field-induced phases in a quasi-one-dimensional (Q1D) organic conductor HMTSF-TCNQ (hexamethylene- tetraselenafulvalene- tetracyanoquinodimethane) under a pressure of 1.1 GPa, where the CDW occurring at 30 K is suppressed. The work was carried out by measurements of angular-dependent magnetoresistance oscillations and exploratory work on the Hall effect. It turned out that the FI-phase, most likely a FICDW for B > 0.1 T, accompany a quantum Hall effect, and the FI-phase transitions are controlled by the field component along the least conducting axis. Above 10 T, the lowest Landau level of the small 2D Fermi pocket (due to incomplete nesting of Fermi surface) exceeds the Fermi level, reaching the quantum limit. Although there are many differences between the CDW (HMTSF-TCNQ) and SDW ((TMTSF)2X) systems, a similar scenario for field-induced phases seems to hold.

  17. Magnetic-Field-Induced Insulator-Metal Transition in (Pr1?yYy)0.7Ca0.3CoO3 at Ultrahigh Magnetic Fields

    NASA Astrophysics Data System (ADS)

    Lee, Suyeon; Matsuda, Yasuhiro H.; Naito, Tomoyuki; Nakamura, Daisuke; Takeyama, Shojiro

    2015-04-01

    The (Pr1?yYy)0.7Ca0.3CoO3 (y ? 0.0625) compounds show a first-order metal-insulator (MI) transition and simultaneous spin-state (SS) transition upon a change in the temperature. We have measured the electrical resistivity of the samples with y = 0.075 (the transition temperature, TMI = 64 K) and 0.10 (TMI = 93 K) in ultrahigh magnetic fields of up to 120 T using a contactless radio-frequency transmission technique. We observed a magnetic-field-induced insulator-metal (IM) transition with large hysteresis below TMI and obtained the temperature-magnetic field phase diagrams. A possible mechanism of the field-induced IM and SS transitions is discussed.

  18. A cascade of magnetic field induced spin transitions in LaCoO{<_3}.

    SciTech Connect

    Altarawneh, M. M.; Chern, G.-W.; Harrison, N.; Batista, C. D.; Uchida, A.; Jaime, M.; Rickel, D. G.; Crooker, S. A.; Mielke, C. H.; Betts, J. B.; Mitchell, J. F.; Hoch, M. J. R. (Materials Science Division); (Los Alamos Nat. Lab.); (Mu'tah Univ.); (Florida State Univ.)

    2012-07-20

    We present magnetization and magnetostriction studies of LaCoO{sub 3} in magnetic fields approaching 100 T. In contrast with expectations from single-ion models, the data reveal two distinct first-order transitions and well-defined magnetization plateaus. The magnetization at the higher plateau is only about half the saturation value expected for spin-1 Co{sup 3+} ions. These findings strongly suggest collective behavior induced by interactions between different electronic configurations of Co{sup 3+} ions. We propose a model that predicts crystalline spin textures and a cascade of four magnetic phase transitions at high fields, of which the first two account for the experimental data.

  19. High Magnetic Field Induced Charge Density Wave State in a Quasi-One-Dimensional Organic Conductor

    NASA Astrophysics Data System (ADS)

    Graf, D.; Choi, E. S.; Brooks, J. S.; Matos, M.; Henriques, R. T.; Almeida, M.

    2004-08-01

    The quasi-one-dimensional organic conductor (Per)2Pt(mnt)2 exhibits a charge density wave ground state below 8 K. Magnetoresistance and magnetization measurements show that the charge density wave is suppressed with magnetic fields of order 20 T, above which a high resistance state, with a cascade of subphases, appears. This new state, tentatively identified as a field induced charge density wave, reenters a low resistance state above 40 T. The results are presented in light of theoretical work [D. Zanchi et al.

    Phys. Rev. BPRBMDO0163-1829 53, 1240 (1996).10.1103/PhysRevB.53.1240
    ] involving field induced charge density wave ground states in high magnetic fields.

  20. The magnetic field induced phase separation in a model of a superconductor with local electron pairing.

    PubMed

    Kapcia, Konrad; Robaszkiewicz, Stanis?aw

    2013-02-13

    We have studied the extended Hubbard model with pair hopping in the atomic limit for arbitrary electron density and chemical potential and focus on paramagnetic effects of the external magnetic field. The Hamiltonian considered consists of (i) the effective on-site interaction U and (ii) the intersite charge exchange interactions I, determining the hopping of electron pairs between nearest-neighbour sites. The phase diagrams and thermodynamic properties of this model have been determined within the variational approach (VA), which treats the on-site interaction term exactly and the intersite interactions within the mean-field approximation. Our investigation of the general case shows that the system can exhibit not only the homogeneous phases-superconducting (SS) and non-ordered (NO)-but also the phase separated states (PS: SS-NO). Depending on the values of interaction parameters, the PS state can occur in higher fields than the SS phase (field induced PS). Some ground state results beyond the VA are also presented. PMID:23334285

  1. Magnetic field-induced currents in the human body in proximity of power lines

    SciTech Connect

    Stuchly, M.A.; Zhao, S. [Univ. of Victoria, British Columbia (Canada). Dept. of Electrical and Computer Engineering] [Univ. of Victoria, British Columbia (Canada). Dept. of Electrical and Computer Engineering

    1996-01-01

    Electric currents induced due to 60 Hz magnetic fields in a human body placed in a close proximity of various high voltage transmission lines are computed. A realistic model of the human body from the anatomical and electrical point of view with resolution of 1.3 cm for the body and 0.665 cm for the head is used. The computations are performed using the impedance method. Three representative configurations of high voltage transmission lines, namely 500 kV, 138 kV and 25 kV are analyzed. The results indicate that the maximum current densities of the order of 0.2 {micro}A/cm{sup 2} can be induced in a lineman working on a 500 kV line (0.5 m away from closest conductors). A good correlation can be seen between the computed magnetic field in the location of the human body and the induced current densities. The induced currents computed here and estimated from measured magnetic fields in various power line environments are compared to those for typical home and office exposures, including appliances.

  2. Magnetic field induced enlargement of the regime of critical fluctuations in the classical superconductor V3Si from high-resolution specific heat experiments

    NASA Astrophysics Data System (ADS)

    Zheng, Y.; Liu, Y.; Toyota, N.; Lortz, R.

    2015-02-01

    We present high-resolution specific heat data from a high-purity single crystal of the classical superconductor V3Si, which reveal tiny lambda-shape anomalies at the superconducting transition superimposed onto the BCS specific heat jump in magnetic fields of 2 T and higher. The appearance of these anomalies is accompanied by a magnetic-field-induced broadening of the superconducting transition. We demonstrate, using scaling relations predicted by the fluctuation models of the 3d-XY and the 3d-lowest-Landau-level (3d-LLL) universality class that the effect of critical fluctuations becomes experimentally observable due to of a magnetic field-induced enlargement of the regime of critical fluctuations. The scaling indicates that a reduction of the effective dimensionality due to the confinement of quasiparticles into low Landau levels is responsible for this effect.

  3. Pulsed Magnetic Field Induced “Analgesia” in the Land Snail, Cepaea nemoralis, and the Effects of ?, ?, and ? Opioid Receptor Agonists\\/Antagonists

    Microsoft Academic Search

    A. W Thomas; M Kavaliers; F. S Prato; K.-P Ossenkopp

    1997-01-01

    Thomas, A. W., M. Kavaliers, F. S. Prato and K.-P. Ossenkopp. Pulsed magnetic field induced “analgesia” in the land snail, Cepaea nemoralis, and the effects of ?, ?, and ? opioid receptor agonists\\/antagonists. Peptides 18(5) 703–709, 1997.—A brief exposure to a pulsed magnetic field (Cnp: patent pending) had significant antinociceptive or “analgesic” effects in the land snail, Cepaea nemoralis, as

  4. Effects of partial substitution of Co on magnetocrystalline anisotropy and magnetic-field-induced strain in NiFeGa alloys

    Microsoft Academic Search

    H. Morito; K. Oikawa; A. Fujita; K. Fukamichi; R. Kainuma; K. Ishida; T. Takagi

    2005-01-01

    The effects of partial substitution of Co on magnetocrystalline anisotropy and magnetic-field-induced strain (MFIS) in Ni–Fe–Ga alloys have been investigated. To obtain a single-variant state in the martensite phase, uniaxial compressive stresses were applied to the single-crystalline specimen. The Curie temperature TC is increased up to 405K by a partial substitution of 6at% Co. The single-variant martensite phase in the

  5. Equilibrium properties of a quadrupolar glass

    NASA Astrophysics Data System (ADS)

    Tadi?, B.; Pirc, R.; Blinc, R.; Petersson, J.; Wiotte, W.

    1994-10-01

    We introduce a semimicroscopic discrete-state model appropriate to the orientational glass phase in mixed alkali halide cyanides with <111> equilibrium orientations of the CN- ions, such as K(CN)xBr1-x. The order-parameter fields are defined as symmetry adapted combinations of the occupation number operators along the cubic body diagonals, which transform according to the T2g representation of the cubic group. These interact via an infinite-range random interaction in the presence of quenched local random strains. We then use the replica formalism to derive a replica-symmetric solution for the components of the orientational-glass order parameter, the linear susceptibilities, and the elastic compliances. The high-temperature orientational-glass phase is characterized by an isotropic order-parameter matrix with only the diagonal elements q? being nonzero. At high temperatures, the behavior of the order parameter q=??q?/3 is similar to that of an Ising spin glass, however, at intermediate and low temperatures the two models differ significantly. We also derive the instability line Tf(?) separating the replica-symmetric isotropic phase from the low-temperature anisotropic orientational glass phase, which is characterized by broken replica symmetry. In contrast to the random-bond-random-field model of an Ising spin glass, the instability temperature increases with random-field variance, implying that in quadrupolar glasses replica-symmetry breaking may be relevant already at relatively high temperatures. Finally, an expression for the distribution of local strains related to the NMR line shape is derived. It is also shown that the quadrupolar glass order parameter can be determined by NMR.

  6. Quantum manipulation on the Barium quadrupolar transition

    E-print Network

    Blatt, Rainer

    and stabilization of a new fiber laser system to ma- nipulate the Barium quadrupolar transition, with the aim . . . . . . . . . . . . . . . 55 6 Spectroscopy and sideband cooling on a single 138 Ba+ 58 6.1 Quantum jumps using the fiber laser . . . . . . . . . . . . .Quantum manipulation on the Barium quadrupolar transition A diploma thesis in physics submitted

  7. Direct evidence on magnetic-field-induced phase transition in a NiCoMnIn ferromagnetic shape memory alloy under a stress field

    SciTech Connect

    Wang, Y. D.; Ren Yang; Huang, E. W.; Nie, Z. H.; Wang, G.; Liu, Y. D.; Deng, J. N.; Zuo, L.; Choo, H.; Liaw, P. K.; Brown, D. E. [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang 110004 (China) and Department of Materials Science and Engineering, The University of Tennessee, Knoxville, Tennessee 37996 (United States); X-ray Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States); Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang 110004 (China); Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States); Department of Physics, Northern Illinois University, DeKalb, Illinois 60115 (United States)

    2007-03-05

    The magnetoelasticity and magnetoplasticity behaviors of a Ni-Co-Mn-In ferromagnetic shape memory alloy (FSMA) induced by the reverse phase transformation interplayed under multiple (temperature, magnetic, and stress) fields were captured directly by high-energy synchrotron x-ray diffraction technique. The experiments showed the direct experimental evidence of that a stress ({approx}50 MPa) applied to this material made a complete recovery of the original orientations of the martensite variants, showing a full shape memory effect. This finding offers the in-depth understanding the fundamental properties and applications of the Ni-Co-Mn-In FSMA with the magnetic-field-induced reverse transformation.

  8. Direct evidence on magnetic-field-induced phase transition in a NiCoMnIn ferromagnetic shape memory alloy under a stress field.

    SciTech Connect

    Wang, Y. D.; Ren, Y.; Huang, E. W.; Nie, Z. H.; Wang, G.; Liu, Y. D.; Deng, J. N.; Zuo, L.; Choo, H.; Liaw, P .K.; Brown, D. E.; Univ. of Tennessee; Northeastern Univ.; Northern Illinois Univ.

    2007-01-01

    The magnetoelasticity and magnetoplasticity behaviors of a Ni-Co-Mn-In ferromagnetic shape memory alloy (FSMA) induced by the reverse phase transformation interplayed under multiple (temperature, magnetic, and stress) fields were captured directly by high-energy synchrotron x-ray diffraction technique. The experiments showed the direct experimental evidence of that a stress ({approx}50 MPa) applied to this material made a complete recovery of the original orientations of the martensite variants, showing a full shape memory effect. This finding offers the in-depth understanding the fundamental properties and applications of the Ni-Co-Mn-In FSMA with the magnetic-field-induced reverse transformation.

  9. Magnetic field-induced elastic bending in bilayers of Tb1-xDyxFe2-y and Pb(Zr1-zTiz)O3

    NASA Astrophysics Data System (ADS)

    Jin, Tao; qichao, Wu; Ning, Zhang

    2014-09-01

    Magnetic field-induced strain in the magnetoelectric bilayers of Tb1-xDyxFe2-y and Pb(Zr1-zTiz)O3 was studied. A butterfly shaped strain curve was observed on the surface of Pb(Zr1-zTiz)O3. The shape of the strain curve was found to be related to the sample thickness and the volume fraction occupied by the ferroelectrics in the bilayer. Theoretical analysis and experimental results showed that magnetoelastic bending in the bilayer composites was largely responsible for the butterfly strain curve.

  10. Direct evidence on magnetic-field-induced phase transition in a NiCoMnIn ferromagnetic shape memory alloy under a stress field

    NASA Astrophysics Data System (ADS)

    Wang, Y. D.; Ren, Yang; Huang, E. W.; Nie, Z. H.; Wang, G.; Liu, Y. D.; Deng, J. N.; Zuo, L.; Choo, H.; Liaw, P. K.; Brown, D. E.

    2007-03-01

    The magnetoelasticity and magnetoplasticity behaviors of a Ni-Co-Mn-In ferromagnetic shape memory alloy (FSMA) induced by the reverse phase transformation interplayed under multiple (temperature, magnetic, and stress) fields were captured directly by high-energy synchrotron x-ray diffraction technique. The experiments showed the direct experimental evidence of that a stress (˜50MPa) applied to this material made a complete recovery of the original orientations of the martensite variants, showing a full shape memory effect. This finding offers the in-depth understanding the fundamental properties and applications of the Ni-Co-Mn-In FSMA with the magnetic-field-induced reverse transformation.

  11. Boundary conditions for electric quadrupolar continua

    NASA Astrophysics Data System (ADS)

    Yaghjian, A. D.

    2014-12-01

    After defining a continuum using rigorous spatial dispersion equations for the macroscopic, fundamental Floquet modal fields of 3-D periodic metamaterial arrays, boundary conditions are derived for electric quadrupolar continua under the assumption that the electric quadrupolarization density contains no extra delta functions within the interface transition layer (in addition to the delta function that usually occurs in the divergence of the electric quadrupolarization across the interface). A physically reasonable constitutive relation, in which the electric quadrupolarization density is proportional to the spatial derivatives of the electric field, is used to examine this assumption and the applicability of the boundary conditions. It is found that, although extra delta functions can be produced by a transverse magnetic plane wave incident upon an interface, the boundary conditions remain essentially unaffected by these extra delta functions for small enough electrical separation distances between the inclusions of the arrays.

  12. Isotropic chemical shifts and quadrupolar parameters of oxygen-17 using dynamic-angle spinning NMR

    SciTech Connect

    Mueller, K.T.; Baltisberger, J.H.; Wooten, E.W.; Pines, A. [Lawrence Berkeley Laboratory, CA (United States)

    1992-08-20

    Several oxygen-17-enriched silicates were studied using dynamic-angle spinning (DAS) NMR spectroscopy at two magnetic field strengths. The DAS method averages second-order quadrupolar interactions by reorienting a sample about a time-dependent axis, thereby yielding high-resolution spectra for half-odd integer spin quadrupolar nuclei such as oxygen-17. A narrow spectral line is observed for each distinct oxygen site in a powdered sample at the sum of the isotropic chemical shift and the field-dependent isotropic second-order quadrupolar shift. Using equations for the total shift observed at two field strengths, the chemical shift is uniquely determined together with a product of the quadrupolar coupling constant (C{sub Q} = e{sup 2}qQ/h) and the quadrupolar asymmetry parameter ({eta}). For one silicate, the authors demonstrate a computer program that uses the isotropic shifts and quadrupolar products as constraints and provides simulations of overlapped magic-angle spinning line shapes. In this way the quadrupolar parameters, C{sub Q} and {eta}, are determined separately for each crystallographic site. The silicates studied include the discrete orthosilicates larnite (Ca{sub 2}SiO{sub 4}) and forsterite (Mg{sub 2}SiO{sub 4}), as well as diopside (CaMgSi{sub 2}O{sub 6}), wollastonite (CaSiO{sub 3}), and clinoenstatite (MgSiO{sub 3}), which are minerals composed of chains of silicon-oxygen tetrahedra. 49 refs., 2 figs., 2 tabs.

  13. Aliovalent-ion and magnetic field induced phase transition in multiferroic biFe(1-x)Ti(x)O3 system.

    PubMed

    Yadav, K L

    2011-03-01

    Multiferroic compounds with general formula BiFe(1-x)Ti(x)O3 (x = 0.1, 0.2, 0.3 and 0.35) have been synthesized by conventional solid state reaction method. The effect of Ti substitution on ferroelectric and magnetic properties is studied. From X-ray diffraction (XRD) analysis, a rhombohedral to orthorhombic phase transition for x > 0.3 was observed. From SQUID measurements, a magnetic field induced phase transition has been observed in the BiFe(1-x)T(x)O3 system for x = 0.3. An anomaly in dielectric constant and dielectric loss in the vicinity of antiferromagnetic Néel temperature (T(N)) and a small enhancement in magnetization have been observed. Magnetization measurements above room temperature showed no systematic variation in antiferromagnetic Néel temperatures on Ti substitution. Further it is seen that this system shows the coupling between electric and magnetic dipoles exhibiting magnetoelectric (ME) effect at room temperature and possess high dielectric constant. PMID:21449454

  14. Fabrication of one-dimensional Fe3O4/P(GMA-DVB) nanochains by magnetic-field-induced precipitation polymerization.

    PubMed

    Ma, Mingliang; Zhang, Qiuyu; Dou, Jinbo; Zhang, Hepeng; Yin, Dezhong; Geng, Wangchang; Zhou, Yanyang

    2012-05-15

    One-dimensional (1D) magnetic Fe(3)O(4)/P(GMA-DVB) peapod-like nanochains have been successfully synthesized by magnetic-field-induced precipitation polymerization using Fe(3)O(4) as building blocks and P(GMA-DVB) as linker. The Fe(3)O(4) microspheres without surface modification can be arranged with the direction of the external magnetic field in a line via the dipolar interaction between Fe(3)O(4) microspheres and linked permanently via P(GMA-DVB) coating during precipitation polymerization. The length of peapod-like nanochains can be controlled by magnetic field intensity, and the thickness of polymer shell can be tuned by the amount of monomers. Magnetic measurement revealed that these 1D peapod-like nanochains showed highly magnetic sensitivity. In the presence of magnetic field, 1D magnetic Fe(3)O(4)/P(GMA-DVB) peapod-like nanochains can be oriented and aligned along the direction of external magnetic field. PMID:22386309

  15. Magnetic Field-Induced Direct-Indirect Bandgap Crossover in AlxGa1-xAs

    NASA Astrophysics Data System (ADS)

    Alberi, Kirstin; Mialitsin, Aleksej; Fluegel, Brian; Crooker, Scott; Mascarenhas, Angelo

    2015-03-01

    Determining the exact alloy composition and energy at which a direct-indirect bandgap crossover occurs in semiconductor alloys is important for engineering optoelectronic materials. However, some amount of error is usually introduced when establishing the crossover from the extrapolation of the direct and indirect bandgap energy trends measured with a discrete set of alloyed samples. We use high magnetic fields up to 58 T to induce the crossover in a single Al0.376Ga0.624As sample, thereby allowing us to precisely identify the crossover energy at low temperature. The onset of the crossover is marked by a reduction in the photoluminescence peak energy and the emergence of an asymmetric peak lineshape resulting from the competition between the radiative lifetime and carrier migration times in the indirect regime. Analysis of the lineshape progression through the crossover confirms that the crossover can be classified as an alloy disorder broadened, first order phase transition. This work was supported by the DOE Office of Science under Contract DE-AC36-08GO28308. The work at LANL was supported by NSF-DMR-1157490 and the State of Florida.

  16. Evidence for Strong Quadrupolar Pair Interactions in Rare-Earth Palladium Bronzes RPd3S4

    Microsoft Academic Search

    K. Abe; J. Kitagawa; N. Takeda; M. Ishikawa

    1999-01-01

    We report an evidence of order due to quadrupolar pair interactions, taking place along the rare-earth ( R) series of RPd3S4 slightly above their dipolar magnetic order. Specific-heat measurements proved that the R ions in these bronzes possess highly degenerate ground states, which may cause large orbital effects at low temperatures. The magnetic ordering temperatures much exceed those predicted by

  17. Investigation of the effect of a variety of pulse errors on spin I=1 quadrupolar alignment echo spectroscopy

    PubMed Central

    Ma, Xiang; Sun, Cheng; Boutis, Gregory S.

    2011-01-01

    We report on an analysis of a well known three-pulse sequence for generating and detecting spin I=1 quadrupolar order when various pulse errors are taken into account. In the situation of a single quadrupolar frequency, such as the case found in a single crystal, we studied the potential leakage of single and/or double quantum coherence when a pulse flip error, finite pulse width effect, RF transient or a resonance offset is present. Our analysis demonstrates that the four-step phase cycling scheme studied is robust in suppressing unwanted double and single quantum coherence as well as Zeeman order that arise from the experimental artifacts, allowing for an unbiased measurement of the quadrupolar alignment relaxation time, T1Q. This work also reports on distortions in quadrupolar alignment echo spectra in the presence of experimental artifacts in the situation of a powdered sample, by simulation. Using our simulation tool, it is demonstrated that the spectral distortions associated with the pulse artifacts may be minimized, to some extent, by optimally choosing the time between the first two pulses. We highlight experimental results acquired on perdeuterated hexamethylbenzene and polyethelene that demonstrate the efficacy of the phase cycling scheme for suppressing unwanted quantum coherence when measuring T1Q. It is suggested that one employ two separate pulse sequences when measuring T1Q to properly analyze the short time behavior of quadrupolar alignment relaxation data. PMID:21664160

  18. Quadrupolar Interactions in Praseodymium - SILVER(1 - Copper(x)

    NASA Astrophysics Data System (ADS)

    Gotaas, James Alan

    We have utilized magnetization, specific heat, resistivity and diffraction experiments (each as a function of applied magnetic field and temperature) to investigate the magnetic properties of the series of pseudo-binary rare earth-intermetallic compounds PrAg(,1-x)Cu(,x) (for x = 0, 0.15, 0.25, 0.35, 0.4, 0.5, 0.75 and 1.0). For 0 <= x <= 0.4, the samples possess a CsCl -type (cubic) crystal structure and exhibit antiferromagnetic ordering at low temperatures (T(,N) < 11K), as revealed by x-ray and neutron diffraction and magnetization measurements. For x = 0.75 and 1.0, the crystal structure is FeB-type (orthorhombic) and no magnetic ordering occurs for T > 2K. For x = 0.5, the sample undergoes a structural transition from CsCl - to FeB-type upon cooling below 160K. Analysis of magnetization measurements reveals that, in addition to the typical bilinear exchange interactions, the CsCl-type compounds also possess effective negative quadrupolar interactions which increase in magnitude by a factor of five as x increases from 0 to 0.4. Such negative (antiferroquadropolar) interactions favor quadrature alignment of neighboring quadrupoles. Specific heat and resistivity measurements indicate that the magnetic order-disorder transition for x = 0 is a typical antiferromagnetic-paramagnetic transition, displaying a sharp peak in C(,m) vs T and a well-defined spin-disorder contribution to the resistivity. As x increases, however, the peak in the magnetic specific heat broadens and decreases in magnitude, accompanied by a change in the rate of development of entropy and a change in the nature of the magnetic excitations in the ordered state. In addition, the change in the resistivity at the magnetic transition becomes more gradual, and the apparent spin-disorder terms becomes a factor of four smaller. The effective quadrupolar interactions in these systems linked to incipient structural instabilities in the CsCl-type structure which ultimately lead to the structural transition for large enough x, with the interactions resulting from a Jahn-Teller-type coupling to zone boundary phonons which are presume to soften as the compounds approach the critical composition. The resulting competition between the bilinear and antiferroquadrupolar interactions modifies the nature of the magnetic phase transition.

  19. Sympathetic solar eruptions in quadrupolar magnetic configurations

    NASA Astrophysics Data System (ADS)

    Torok, T.; Titov, V. S.; Panasenco, O.

    2014-12-01

    Observations by SDO/AIA have renewed the interest in sympathetic solareruptions, i.e., of eruptions that occur simultaneously (or in shortsuccession) at different source regions in the corona. Recently, Toroket al. (2011) developed an idealized numerical model for the triggermechanisms of sympathetic eruptions in so-called pseudo-streamers, whichconsist of a tri-polar magnetic configuration with a parasitic polarityin their center. Here we extend the work by Torok et al. by investigating sympathetic eruptions in (the topologically somewhat more complex) quadrupolar configurations, using MHD simulations. We consider both symmetric and asymmetric initial configurations that contain two or three flux ropes within the quadrupole. We find, differentto Torok et al. (2011), that magnetic reconnection induced by a firsteruption cannot just trigger, but also prevent subsequent eruptions. In addition, a (relatively modest) asymmetry of the configuration may fully suppress the occurrence of successive full eruptions, i.e., of coronal mass ejections. We discuss the implications of these results for our understanding of sympathetic eruptions.

  20. Mean-field model for the quadrupolar phases of UPd3

    NASA Astrophysics Data System (ADS)

    Le, Manh Duc; McEwen, Keith A.; Rotter, Martin; Doerr, Mathias; Barcza, Alexander; Park, Je-Geun; Brooks, James; Jobiliong, Eric; Fort, David

    2014-06-01

    UPd3 is known to exhibit four antiferroquadrupolar ordered phases at low temperatures. We report measur-ements of the magnetization and magnetostriction of single crystal UPd3, along the principal symmetry directions, in fields up to 33 T. These results have been combined with recent inelastic neutron and x-ray resonant scattering measurements to construct a mean-field model of UPd3 including up to fourth nearest-neighbor interactions. In particular, we find that anisotropic quadrupolar interactions must be included in order to explain the low-temperature structures derived from the scattering data.

  1. Kn 26, a new quadrupolar planetary nebula

    NASA Astrophysics Data System (ADS)

    Guerrero, M. A.; Miranda, L. F.; Ramos-Larios, G.; Vázquez, R.

    2013-03-01

    Once classified as an emission line source, the planetary nebula (PN) nature of the source Kn 26 has only recently been recognized in digital sky surveys. To investigate the spectral properties and spatio-kinematical structure of Kn 26, we have obtained high spatial-resolution optical and near-IR narrow-band images, high-dispersion long-slit echelle spectra, and intermediate-resolution spectroscopic observations. The new data reveal an hourglass morphology typical of bipolar PNe. A detailed analysis of its morphology and kinematics discloses the presence of a second pair of bipolar lobes, making Kn 26 a new member of the subclass of quadrupolar PNe. The time lapse between the ejection of the two pairs of bipolar lobes is much shorter than their dynamical ages, implying a rapid change in the preferential direction of the central engine. The chemical composition of Kn 26 is particularly unusual among PNe, with a low N/O ratio (as for type II PNe) and a high helium abundance (as for type I PNe), although not atypical among symbiotic stars. Such an anomalous chemical composition may have resulted from the curtailment of the time in the asymptotic giant branch by the evolution of the progenitor star through a common envelope phase. Based on observations made with the Nordic Optical Telescope (NOT) and the William Herschel Telescope (WHT) on the island of La Palma in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias (IAC), the 2.1-m telescope of the Observatorio Astronómico Nacional at the Sierra de San Pedro Mártir (OAN-SPM), and the 1.5-m telescope at the Observatorio de Sierra Nevada (OSN), Granada, Spain. NOT is operated jointly by Denmark, Finland, Iceland, Norway, and Sweden. WHT is operated by the Isaac Newton Group. The 2.1-m telescope at the OAN-SPM is a national facility operated by the Instituto de Astronomía of the Universidad Nacional Autónoma de México. The 1.5-m telescope at the OSN is operated by the Instituto de Astrofísica de Andalucía (IAA).The data presented here were obtained in part with ALFOSC, which is provided by the IAA under a joint agreement with the University of Copenhagen and NOTSA.FITS files for spectra and images are available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr(130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/551/A53

  2. On the application of magic echo cycles for quadrupolar echo spectroscopy of spin-1 nuclei

    NASA Astrophysics Data System (ADS)

    Mananga, E. S.; Roopchand, R.; Rumala, Y. S.; Boutis, G. S.

    2007-03-01

    Magic echo cycles are introduced for performing quadrupolar echo spectroscopy of spin-1 nuclei. An analysis is performed via average Hamiltonian theory showing that the evolution under chemical shift or static field inhomogeneity can be refocused simultaneously with the quadrupolar interaction using these cycles. Due to the higher convergence in the Magnus expansion, with sufficient RF power, magic echo based quadrupolar echo spectroscopy outperforms the conventional two pulse quadrupolar echo in signal to noise. Experiments highlighting a signal to noise enhancement over the entire bandwidth of the quadrupolar pattern of a powdered sample of deuterated polyethelene are shown.

  3. On the application of magic echo cycles for quadrupolar echo spectroscopy of spin-1 nuclei.

    PubMed

    Mananga, E S; Roopchand, R; Rumala, Y S; Boutis, G S

    2007-03-01

    Magic echo cycles are introduced for performing quadrupolar echo spectroscopy of spin-1 nuclei. An analysis is performed via average Hamiltonian theory showing that the evolution under chemical shift or static field inhomogeneity can be refocused simultaneously with the quadrupolar interaction using these cycles. Due to the higher convergence in the Magnus expansion, with sufficient RF power, magic echo based quadrupolar echo spectroscopy outperforms the conventional two pulse quadrupolar echo in signal to noise. Experiments highlighting a signal to noise enhancement over the entire bandwidth of the quadrupolar pattern of a powdered sample of deuterated polyethelene are shown. PMID:17140824

  4. Magnetic field induced changes in the critical exponent {beta} of the chiral triangular antiferromagnet CsMnBr{sub 3} in the presence of an electric field (abstract)

    SciTech Connect

    Visser, D. [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom)] [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom); Monteith, A.R. [The Royal Institution of Great Britain, 21 Albemarle Street, London W1X 4BS (United Kingdom)] [The Royal Institution of Great Britain, 21 Albemarle Street, London W1X 4BS (United Kingdom); Bargawi, A.Y. [Department of Physics, Umm Al-Qura University, Makkah (Saudi Arabia)] [Department of Physics, Umm Al-Qura University, Makkah (Saudi Arabia); Zeiske, T. [BENSC, Hahn Meitner Institut, Glienecker Strasse 100, Berlin (Germany)] [BENSC, Hahn Meitner Institut, Glienecker Strasse 100, Berlin (Germany)

    1997-04-01

    The magnetic moments in the triangular antiferromagnetic CsMnBr{sub 3} order at T{sub N}=8.3 K with a frustration of the magnetic moments in a 120{degree} type magnetic structure. The magnetic moments are either ordered in a clockwise or an anticlockwise direction resulting in a chirality ordering, which is characterized by the critical exponent of the magnetic sublattice magnetization {beta}=0.25. It has been shown that an electric field applied along the [110] direction removes the chiral ordering and a linear Ising-like phase will be established; consequently, the value of {beta} decreases. The subsequent application of a magnetic field of B=4 T along the [100] direction causes the critical exponent {beta} to increase. The magnetic phase diagram of CsMnBr{sub 3} does not change due to the introduction of an electric field.{copyright} {ital 1997 American Institute of Physics.}

  5. Four-component Hartree-Fock calculations of magnetic-field induced circular birefringence—Faraday effect—in noble gases and dihalogens

    Microsoft Academic Search

    Ulf Ekström; Patrick Norman; Antonio Rizzo

    2006-01-01

    level of theory. A measure of the birefringence is given by the Verdet constant, which is a third-order molecular property and thus relates to quadratic response functions. A fully analytical nonlinear polarization propagator approach is employed. The results are gauge invariant as a consequence of the spatial symmetries in the molecular systems. The calculations include electronic as well as vibrational

  6. Vanillin-molecularly targeted extraction of stir bar based on magnetic field induced self-assembly of multifunctional Fe3O4@Polyaniline nanoparticles for detection of vanilla-flavor enhancers in infant milk powders.

    PubMed

    Wu, Jinhua; Yang, Zaiyue; Chen, Ning; Zhu, Wanying; Hong, Junli; Huang, Changgao; Zhou, Xuemin

    2015-03-15

    A molecularly imprinted stir bar was constructed based on Fe3O4@Polyaniline nanoparticles with magnetic field-induced self-assembly process. The monomer, methacrylic acid, was pre-assembled into the pre-polymers with vanillin as template by the formation of hydrogen bonds. After that, the magnetic complexes were generated by the hydrogen bonding, the hydrophobic and ?-? interaction between the pre-polymers and Fe3O4@Polyaniline. The complexes were adsorbed on the surface of magnetic stir bar under the magnetic induction, and the coating of vanillin-molecularly imprinted polymers was generated by the one-step copolymerization basing on the cross linking of ethylene glycol dimethacrylate. The molecular imprinting stir bar showed superior selectivity and fast binding kinetics for vanillin, and was used for the enrichment of vanilla-flavor enhancers (vanillin, ethyl maltol and methyl vanillin) in infant milk powders. The results measured by HPLC-UV exhibited good linear ranges of 0.01-100, 0.02-100 and 0.03-100?gmL(-1) with the limit of detection of 2.5-10.0ngmL(-1), and the recoveries were 94.7-98.9%, 82.1-96.7% and 84.5-93.2% with RSD<7.2% for the three enhancers, respectively. PMID:25514645

  7. Magnetic field cycling effect on the non-linear current-voltage characteristics and magnetic field induced negative differential resistance in ?-Fe1.64Ga0.36O3 oxide

    NASA Astrophysics Data System (ADS)

    Bhowmik, R. N.; Vijayasri, G.

    2015-06-01

    We have studied current-voltage (I-V) characteristics of ?-Fe1.64Ga0.36O3, a typical canted ferromagnetic semiconductor. The sample showed a transformation of the I-V curves from linear to non-linear character with the increase of bias voltage. The I-V curves showed irreversible features with hysteresis loop and bi-stable electronic states for up and down modes of voltage sweep. We report positive magnetoresistance and magnetic field induced negative differential resistance as the first time observed phenomena in metal doped hematite system. The magnitudes of critical voltage at which I-V curve showed peak and corresponding peak current are affected by magnetic field cycling. The shift of the peak voltage with magnetic field showed a step-wise jump between two discrete voltage levels with least gap (?VP) 0.345(± 0.001) V. The magnetic spin dependent electronic charge transport in this new class of magnetic semiconductor opens a wide scope for tuning large electroresistance (˜500-700%), magnetoresistance (70-135 %) and charge-spin dependent conductivity under suitable control of electric and magnetic fields. The electric and magnetic field controlled charge-spin transport is interesting for applications of the magnetic materials in spintronics, e.g., magnetic sensor, memory devices and digital switching.

  8. Optical properties and magnetic-field-induced phase transitions in the ferroelectric state of Ni3V2O8 : Experiments and first-principles calculations

    NASA Astrophysics Data System (ADS)

    Rai, R. C.; Cao, J.; Brown, S.; Musfeldt, J. L.; Kasinathan, D.; Singh, D. J.; Lawes, G.; Rogado, N.; Cava, R. J.; Wei, X.

    2006-12-01

    We use a combination of optical spectra, first-principles calculations, and energy-dependent magneto-optical measurements to elucidate the electronic structure and to study the phase diagram of Ni3V2O8 . We find a remarkable interplay of magnetic field and optical properties that reveals additional high magnetic-field phases and an unexpected electronic structure, which we associate with the strong magnetodielectric couplings in this material over a wide energy range. Specifically, we observed several prominent magnetodielectric effects that derive from changes in the crystal-field environment around Ni spine and cross tie centers. This effect is consistent with a field-induced modification of local structure. Symmetry-breaking effects are also evident with temperature. We find Ni3V2O8 to be an intermediate-gap, local-moment band insulator. This electronic structure is particularly favorable for magnetodielectric couplings, because the material is not subject to the spin-charge separation characteristic of strongly correlated large-gap Mott insulators, while at the same time remaining a magnetic insulator independent of the particular spin order and temperature.

  9. High-resolution solid-state NMR of quadrupolar nuclei

    Microsoft Academic Search

    Eric Oldfield; Hye Kyung C. Timken; Ben Montez; R. Ramachandran

    1985-01-01

    Quadrupolar nuclei are the most abundant nuclear magnetic resonance (NMR)-receptive nuclei in the Earth's crust, and in many amorphous materials of technological interest (such as zeolite catalysts, ceramics and alloys), and have thus been intensively studied1-7. Of particular interest is the ability to resolve and quantitate the various types of sites present in a given material. Here we present a

  10. Cross polarization for quadrupolar nuclei—Proton to sodium-23

    NASA Astrophysics Data System (ADS)

    Harris, Robin K.; Nesbitt, Geoffrey J.

    The role of cross polarization in magic-angle spinning spectra of quadrupolar nuclei for solids is discussed, using the 1H ? 23Na case as an example. Suitable materials for spectrometer tuning in this mode are proposed and sample spectra presented. Some relaxation experiments on the 23Na signals for borax were carried out, and the selectivity of the cross-polarization experiment is shown for the layer mineral kenyaite.

  11. Fluctuating magnetic field induced resonant activation.

    PubMed

    Mondal, Shrabani; Das, Sudip; Baura, Alendu; Bag, Bidhan Chandra

    2014-12-14

    In this paper, we have studied the properties of a Brownian particle at stationary state in the presence of a fluctuating magnetic field. Time dependence of the field makes the system thermodynamically open. As a signature of that the steady state distribution function becomes function of damping strength, intensity of fluctuations and constant parts of the applied magnetic field. It also depends on the correlation time of the fluctuating magnetic field. Our another observation is that the random magnetic field can induce the resonant activation phenomenon. Here correlation time is increased under the fixed variance of the fluctuating field. But if the correlation time (?) increases under the fixed field strength then the mean first passage time rapidly grows at low ? and it almost converges at other limit. This is sharp contrast to the usual colored noise driven open system case where the mean first passage time diverges exponentially. We have also observed that a giant enhancement of barrier crossing rate occurs particularly at large strength of constant parts of the applied magnetic field even for very weak fluctuating magnetic field. Finally, break down of the Arrhenius result and disappearance of the Kramers' turn over phenomenon may occur in the presence of a fluctuating magnetic field. PMID:25494726

  12. On the relationship between quadrupolar magnetic field and collisionless reconnection

    SciTech Connect

    Smets, R., E-mail: roch.smets@lpp.polytechnique.fr; Belmont, G. [LPP, University P. and M. Curie, CNRS, Ecole Polytechnique, F-91128 Palaiseau (France); Aunai, N. [IRAP, University Paul Sabatier, F-31028 Toulouse (France); Boniface, C. [CEA/DAM, DIF, F-91297 Arpajon (France); Fuchs, J. [LULI, Ecole Polytechnique, CNRS, CEA, University P. and M. Curie, F-91128 Palaiseau (France)

    2014-06-15

    Using hybrid simulations, we investigate the onset of fast reconnection between two cylindrical magnetic shells initially close to each other. This initial state mimics the plasma structure in High Energy Density Plasmas induced by a laser-target interaction and the associated self-generated magnetic field. We clearly observe that the classical quadrupolar structure of the out-of-plane magnetic field appears prior to the reconnection onset. Furthermore, a parametric study reveals that, with a non-coplanar initial magnetic topology, the reconnection onset is delayed and possibly suppressed. The relation between the out-of-plane magnetic field and the out-of-plane electric field is discussed.

  13. Quadrupolar Kondo effect in uranium heavy-electron materials?

    NASA Technical Reports Server (NTRS)

    Cox, D. L.

    1987-01-01

    The possibility of an electric quadrupole Kondo effect for a non-Kramers doublet on a uranium (U) ion is a cubic metallic host is demonstrated by model calculations showing a Kondo upturn in the resistivity, universal quenching of the quadrupolar moment, and a heavy-electron anomaly in the electronic specific heat. With inclusion of excited crystal-field levels, some of the unusual magnetic-response data in the heavy-electron superconductor UBe13 may be understood. Structural phase transitions at unprecedented low temperatures may occur in U-based heavy-electron materials.

  14. Radio-frequency-mediated dipolar recoupling among half-integer quadrupolar spins

    E-print Network

    Griffin, Robert G.

    Radio-frequency-mediated dipolar recoupling among half-integer quadrupolar spins Marc Baldus quadrupolar spins in the presence of an appropriate radio-frequency field. Experimental and theoretical in close spatial proximity. Unfortunately, most spin-1/2 methods involving radio frequency rf irradiation

  15. Spin Squeezing in a Quadrupolar Nuclei NMR System

    NASA Astrophysics Data System (ADS)

    Auccaise, R.; Araujo-Ferreira, A. G.; Sarthour, R. S.; Oliveira, I. S.; Bonagamba, T. J.; Roditi, I.

    2015-01-01

    We have produced and characterized spin-squeezed states at a temperature of 26 °C in a nuclear magnetic resonance quadrupolar system. The experiment was carried out on 133Cs nuclei of spin I =7 /2 in a sample of lyotropic liquid crystal. The source of spin squeezing was identified as the interaction between the quadrupole moment of the nuclei and the electric field gradients present within the molecules. We use the spin angular momentum representation to describe formally the nonlinear operators that produce the spin squeezing on a Hilbert space of dimension 2 I +1 =8 . The quantitative and qualitative characterization of this spin-squeezing phenomenon is expressed by a squeezing parameter and squeezing angle developed for the two-mode Bose-Einstein condensate system, as well as by the Wigner quasiprobability distribution function. The generality of the present experimental scheme points to potential applications in solid-state physics.

  16. Spin squeezing in a quadrupolar nuclei NMR system.

    PubMed

    Auccaise, R; Araujo-Ferreira, A G; Sarthour, R S; Oliveira, I S; Bonagamba, T J; Roditi, I

    2015-01-30

    We have produced and characterized spin-squeezed states at a temperature of 26?°C in a nuclear magnetic resonance quadrupolar system. The experiment was carried out on 133Cs nuclei of spin I=7/2 in a sample of lyotropic liquid crystal. The source of spin squeezing was identified as the interaction between the quadrupole moment of the nuclei and the electric field gradients present within the molecules. We use the spin angular momentum representation to describe formally the nonlinear operators that produce the spin squeezing on a Hilbert space of dimension 2I+1=8. The quantitative and qualitative characterization of this spin-squeezing phenomenon is expressed by a squeezing parameter and squeezing angle developed for the two-mode Bose-Einstein condensate system, as well as by the Wigner quasiprobability distribution function. The generality of the present experimental scheme points to potential applications in solid-state physics. PMID:25679893

  17. Preparing Pseudo-Pure States in a Quadrupolar Spin System Using Optimal Control

    NASA Astrophysics Data System (ADS)

    Tan, Yi-Peng; Nie, Xin-Fang; Li, Jun; Chen, Hong-Wei; Zhou, Xian-Yi; Peng, Xin-Hua; Du, Jiang-Feng

    2012-12-01

    Pseudo-pure state (PPS) preparation is crucial in nuclear magnetic resonance quantum computation. There have been some methods in spin-1/2 systems and a few attempts in quadrupolar spin systems. As optimal control via gradient ascent pulses engineering (GRAPE) has been widely used in quantum information science, we apply this technique to PPS preparation in quadrupolar spin systems. This approach shows an effective and fast quantum control method for both the state preparation and the realization of quantum gates in quadrupolar systems.

  18. NMR evidence for higher-order multipole order parameters in NpO2.

    PubMed

    Tokunaga, Y; Aoki, D; Homma, Y; Kambe, S; Sakai, H; Ikeda, S; Fujimoto, T; Walstedt, R E; Yasuoka, H; Yamamoto, E; Nakamura, A; Shiokawa, Y

    2006-12-22

    We report a microscopic investigation of multipolar order parameters in the ordered state of NpO2 conducted via 17O NMR on a single crystal. From the angular dependence of hyperfine fields at 17O nuclei, we have obtained clear evidence for the appearance of field-induced antiferro-octupolar as well as field-induced antiferro-dipolar moments below T0 = 26 K. We have also observed oscillatory spin-echo decay, which is well understood in terms of small electric field gradients created by antiferro-quadrupolar ordering. This reveals that the quadrupolar order parameter is directly observable by means of NMR. The present NMR studies provide definitive support for a proposed longitudinal triple-q type octupolar-quadrupolar ordering model for NpO2. PMID:17280392

  19. Long-Range Electron Binding to Quadrupolar Molecules C. Desfrancois, Y. Bouteiller, and J. P. Schermann

    E-print Network

    Simons, Jack

    Long-Range Electron Binding to Quadrupolar Molecules C. Desfranc¸ois, Y. Bouteiller, and J. P electron can be bound to a molecule in a very diffuse orbital as a result of the long-range contributions be trapped in the molecular potential well essentially created by the long-range at- tractive fields plus

  20. Electrical Nuclear Quadrupolar Interaction of ZINC67 in a Single Crystal of Zinc

    Microsoft Academic Search

    Jacques Goyette

    1986-01-01

    The nuclear quadrupolar coupling of ('67)Zn in a single crystal of zinc has been studied using the techniques of nuclear acoustic resonance (NAR) and nuclear magnetic resonance (NMR) at low temperatures. NAR, which is an attractive way of doing resonance experiments, is analogous to NMR except in the fact that we use phonons instead of photons to induce transitions thereby

  1. New methods and applications in solid-state NMR spectroscopy of quadrupolar nuclei.

    PubMed

    Ashbrook, Sharon E; Sneddon, Scott

    2014-11-01

    Solid-state nuclear magnetic resonance (NMR) spectroscopy has long been established as offering unique atomic-scale and element-specific insight into the structure, disorder, and dynamics of materials. NMR spectra of quadrupolar nuclei (I > (1)/2) are often perceived as being challenging to acquire and to interpret because of the presence of anisotropic broadening arising from the interaction of the electric field gradient and the nuclear electric quadrupole moment, which broadens the spectral lines, often over several megahertz. Despite the vast amount of information contained in the spectral line shapes, the problems with sensitivity and resolution have, until very recently, limited the application of NMR spectroscopy of quadrupolar nuclei in the solid state. In this Perspective, we provide a brief overview of the quadrupolar interaction, describe some of the basic experimental approaches used for acquiring high-resolution NMR spectra, and discuss the information that these spectra can provide. We then describe some interesting recent examples to showcase some of the more exciting and challenging new applications of NMR spectra of quadrupolar nuclei in the fields of energy materials, microporous materials, Earth sciences, and biomaterials. Finally, we consider the possible directions that this highly informative technique may take in the future. PMID:25296129

  2. Effect of IL-1?-Induced Macromolecular Depletion on Residual Quadrupolar Interaction in Articular Cartilage

    PubMed Central

    Borthakur, Arijitt; Shapiro, Erik M.; Beers, Jennifer; Kudchodkar, Sagar; Kneeland, J. Bruce; Reddy, Ravinder

    2010-01-01

    Purpose Sodium multiple-quantum filtered (MQF) NMR spectroscopy may potentially be used to measure proteoglycan (PG) depletion in cartilage caused by osteoarthritis (OA). The purpose of this work was to quantify the effect of interleukin-1 (IL-1?)-induced macromolecule depletion on the residual quadrupolar interaction (RQI) of sodium in bovine cartilage plugs. Materials and Methods Fifteen 8-mm-diameter cartilage plug specimens were cored from the articular surface of fresh bovine patellae. All plugs were kept in culture media and nine of the plugs were subjected to interleukin-1 (IL-1?)-induced degeneration of cartilage for 4, 6, and 7 days. Sodium NMR spectra were obtained from each sample with a 1-cm-diameter solenoid coil in a 2T whole-body magnet interfaced to a custom-built spectrometer. We employed a previously described theoretical model to analyze triple-quantum filtered (TQF) and double-quantum filtered magic angle (DQFMA) spectra obtained from normal cartilage and cartilage treated with IL-1?. The model assumes a static Gaussian distribution of the RQI frequency, ?Q, in the sample. TQF and DQFMA spectra from each sample were fitted with the appropriate signal expressions to determine ? (the root mean square (RMS) ?Q), T2f, and T2s. An inversion-recovery sequence was used to determine T1 of each plug. A spectrophotometric assay was used to determine the amount of PG depleted from each plug. Histology was performed to visualize the PG loss in cartilage plugs. We defined ? as the measure of changes in macroscopic order in the tissue. Results Simulated spectra from the theoretical model were in excellent agreement with the experimental data. We were able to determine the relaxation times as well as ? of each specimen from their corresponding fits. T2f ranged between 2.26–3.50 msec, decreasing with increased PG loss. Over the range of PG depletion investigated, T2s increased from 12.3 msec to 14.9 msec, and T1 increased from 16 msec to 21 msec, while ? decreased from 180 Hz to 120 Hz. The order of macromolecules in the cartilage tissue decreased substantially with PG loss. Histology sections clearly showed qualitative visualization of the PG loss in cartilage following treatment with IL-1?. Conclusion We demonstrated that IL-?-induced macromolecule depletion in cartilage not only changes the relaxation characteristics of sodium but also changes RQI of the tissue. Using MQF sodium spectroscopy we quantified the changes in ? and showed that loss of macromolecules reduces the degree of order in the tissue. PMID:11891977

  3. Structure evolution and entropy change of temperature and magnetic field induced magneto-structural transition in Mn1.1Fe0.9P0.76Ge0.24

    NASA Astrophysics Data System (ADS)

    Yue, Ming; Liu, Danmin; Huang, Qingzhen; Wang, Tong; Hu, Fengxia; Li, Jingbo; Rao, Guanghui; Shen, Baogen; Lynn, Jeffery W.; Zhang, Jiuxing

    2013-01-01

    The compound Mn1.1Fe0.9P0.76Ge0.24 has been studied using neutron powder diffraction (NPD), differential scanning calorimeter (DSC), and magnetic measurements, in order to clarify the nature of the magnetic and structural transition and measure the associated entropy change (?S). The strongly first order transition occurs from a paramagnetic (PM) to a ferromagnetic (FM) phase and can be induced either by temperature or by an applied magnetic field. Our investigations indicate that the two processes exhibit identical evolutions regarding the crystal and magnetic structures, indicating they should have the same entropy change. We, therefore, conclude that the ?SDSC obtained by the DSC method (where the transition is temperature induced) is valid also for the magnetically induced transition, thus avoiding uncertainties connected with the magnetic measurements. We have obtained the ?SDSC = 33.8 J/kg . K for this sample upon cooling, which would increase to 42.7 J/kg . K for a impurity-free and completely homogeneous sample. For comparison, the magnetic entropy changes (?SM) induced by magnetic field and calculated using the Maxwell relation yields a ?SM = 46.5J/kg . K, 38% higher than ?SDSC. These entropy results are compared and discussed.

  4. Perturbed chain-statistical associating fluid theory extended to dipolar and quadrupolar molecular fluids.

    PubMed

    Karakatsani, Eirini K; Economou, Ioannis G

    2006-05-11

    The perturbed chain statistical associating fluid theory (PC-SAFT) is extended to polar molecular fluids, namely dipolar and quadrupolar fluids. The extension is based on the perturbation theory for polar fluids by Stell and co-workers. Appropriate expressions are proposed for dipole-dipole, quadrupole-quadrupole, and dipole-quadrupole interactions. Furthermore, induced dipole interactions are calculated explicitly in the model. The new polar PC-SAFT model is relatively complex; for this purpose, a truncated polar PC-SAFT model is proposed using only the leading term in the polynomial expansion for polar interactions. The new model is used for the calculation of thermodynamic properties of various quadrupolar pure fluids. In all cases, the agreement between experimental data and model predictions is very good. PMID:16671742

  5. Magnetic-field induced N2(B --> A) emission from a beam of metastable nitrogen molecules and precise term energy of the N2(A' 5Sigma + g) state

    NASA Astrophysics Data System (ADS)

    Ottinger, Ch.; Vilesov, A. F.

    1995-12-01

    Magnetic field anticrossing measurements have been made in order to identify unambiguously the N2(A' 5?+g) level responsible for the recently observed perturbation of the N2(B 3?g, v=10, 3?e2(12)) level [Ch. Ottinger and A. F. Vilesov, J. Chem. Phys. 100, 4862 (1994)]. When a weak magnetic field (H=0-3000 G) was applied across the N2 metastable beam, new field-induced perturbations were observed in B,v=11, which were ascribed to interactions with A', v=2. This multiple perturbation pattern permits a determination of the relative energy of the A' and B states with a precision of 0.02 cm-1.

  6. Quadrupolar correlations and deformation effects on nuclear transition matrix elements of double-{beta} decay

    SciTech Connect

    Rath, P. K. [Department of Physics, University of Lucknow, Lucknow-226007 (India)

    2009-11-09

    The effect of quadrupolar correlations vis-a-vis deformation on the nuclear transition matrix elements of two neutrino and neutrinoless {beta}{beta} decay is studied in the PHFB model. It is observed that the deformation effects scale almost similarly for both the two neutrino and neutrinoless {beta}{beta} decay modes and the independent deformations of initial and final nuclei are important parameters to describe the nuclear transition matrix elements for different modes of {beta}{beta} decay.

  7. High-Resolution NMR of Quadrupolar Nuclei in the Solid State

    SciTech Connect

    Gann, Sheryl Lee

    1995-11-30

    This dissertation describes recent developments in solid state nuclear magnetic resonance (NMR), for the most part involving the use of dynamic-angle spinning (DAS) NMR to study quadrupolar nuclei. Chapter 1 introduces some of the basic concepts and theory that will be referred to in later chapters, such as the density operator, product operators, rotations, coherence transfer pathways, phase cycling, and the various nuclear spin interactions, including the quadrupolar interaction. Chapter 2 describes the theory behind motional averaging experiments, including DAS, which is a technique where a sample is spun sequentially about two axis oriented at different angles with respect to the external magnetic field such that the chemical shift and quadrupolar anisotropy are averaged to zero. Work done on various rubidium-87 salts is presented as a demonstration of DAS. Chapter 3 explains how to remove sidebands from DAS and magic-angle spinning (MAS) experiments, which result from the time-dependence of the Hamiltonian under sample spinning conditions, using rotor-synchronized {pi}-pulses. Data from these experiments, known as DAH-180 and MAH-180, respectively, are presented for both rubidium and lead salts. In addition, the applicability of this technique to double rotation (DOR) experiments is discussed. Chapter 4 concerns the addition of cross-polarization to DAS (CPDAS). The theory behind spin locking and cross polarizing quadrupolar nuclei is explained and a method of avoiding the resulting problems by performing cross polarization at 0{sup o} (parallel) with respect to the magnetic field is presented. Experimental results are shown for a sodium-23 compound, sodium pyruvate, and for oxygen-17 labeled L-akmine. In Chapter 5, a method for broadening the Hartmann-Hahn matching condition under MAS, called variable effective field cross-polarization (VEFCI?), is presented, along with experimental work on adamantane and polycarbonate.

  8. Accretion-driven gravitational radiation from nonrotating compact objects: Infalling quadrupolar shells

    NASA Astrophysics Data System (ADS)

    Nagar, Alessandro; Díaz, Guillermo; Pons, José A.; Font, José A.

    2004-06-01

    This paper reports results from numerical simulations of the gravitational radiation emitted from non-rotating compact objects (both neutron stars and Schwarzschild black holes) as a result of the accretion of matter. We adopt a hybrid procedure in which we evolve numerically, and assuming axisymmetry, the linearized equations describing metric and fluid perturbations coupled to a fully nonlinear hydrodynamics code that calculates the motion of the accreting matter. The initial matter distribution, which is initially at rest, is shaped in the form of extended quadrupolar shells of either dust or obeying a perfect fluid equation of state. Self-gravity of the accreting layers of fluid is neglected, as well as radiation reaction effects. We use this idealized setup in order to understand the qualitative features appearing in the energy spectrum of the gravitational wave emission from compact stars or black holes, subject to accretion processes involving extended objects. A comparison for the case of point-like particles falling radially onto black holes is also provided. Our results show that, when the central object is a black hole, the spectrum is far from having only one clear, monochromatic peak at the frequency of the fundamental quasi-normal mode. On the contrary, it shows a complex pattern, with distinctive interference fringes produced by the interaction between the infalling matter and the underlying perturbed spacetime, in close agreement with results for point-like particles. Remarkably, most of the energy is emitted at frequencies lower than that of the fundamental mode of the black hole. Similar results are obtained for extended shells accreting onto neutron stars, but in this case the contribution of the stellar fundamental mode stands clearly in the energy spectrum. Our analysis illustrates that the gravitational wave signal driven by accretion onto compact objects is influenced more by the details and dynamics of the process, and the external distribution of matter, than by the quasi-normal mode structure of the central object. The gravitational waveforms from such accretion events appear to be much more complex than former simplified assumptions predicted.

  9. Strong Magnetic Field Induced Changes of Gene Expression in Arabidopsis

    NASA Astrophysics Data System (ADS)

    Paul, A.-L.; Ferl, R. J.; Klingenberg, B.; Brooks, J. S.; Morgan, A. N.; Yowtak, J.; Meisel, M. W.

    2005-07-01

    We review our studies of the biological impact of magnetic field strengths of up to 30 T on transgenic arabidopsis plants engineered with a stress response gene consisting of the alcohol dehydrogenase (Adh) gene promoter driving the ?-glucuronidase (GUS) gene reporter. Field strengths in excess of 15 T induce expression of the Adh/GUS transgene in the roots and leaves. Microarray analyses indicate that such field strengths have a far reaching effect on the genome. Wide spread induction of stress-related genes and transcription factors, and a depression of genes associated with cell wall metabolism are prominent examples.

  10. Magnetic-field-induced antiferromagnetism in the Kondo lattice

    E-print Network

    Beach, Kevin S. D. (Kevin Stuart David), 1975-

    2004-01-01

    The half-filled Kondo lattice model, augmented by a Zeeman term, serves as a useful model of a Kondo insulator in an applied magnetic field. A variational mean field analysis of this system on a square lattice, backed up ...

  11. A Conduction Cooled High Temperature Superconductor Quadrupolar Superferric Magnet, Design and Construction

    NASA Astrophysics Data System (ADS)

    Dobrin, I.; Morega, A. M.; Nedelcu, A.; Morega, M.; Neamtu, J.

    2014-05-01

    The paper presents the prototype of an YBCO superferric quadrupolar magnet for high gradient magnetic field generation, design and construction. The temperature of the superconducting coil has to be kept within safe limits or the HTS would exit the superconductive state. Of particular concern is the "warm" beam tube that passes through the magnet. Cryogenic conduction cooling with a closed cycle G-M Cooler may ensure the removal of the ambient heat influx. Numerical simulation results on the magnetic field and heat transfer problems are then discussed. The computational domain is abstracted out of the CAD design of the system. The design solution is presented and compared with the numerical simulations results.

  12. Cross-polarization from quadrupolar nuclei to silicon using low-radio-frequency amplitudes during magic-angle spinning

    SciTech Connect

    De Paul, S.M.; Ernst, M.; Shore, J.S.; Pines, A. [Lawrence Berkeley National Lab., CA (United States)] [Lawrence Berkeley National Lab., CA (United States); [Univ. of California, Berkeley, CA (United States); Stebbins, J.F. [Stanford Univ., CA (United States)] [Stanford Univ., CA (United States)

    1997-04-17

    The dynamics of cross-polarization from the central transition of a quadrupolar nucleus ({sup 27}Al or {sup 23}Na) to a spin-1/2 nucleus ({sup 29}Si) during magic-angle spinning and using low-radio-frequency field strengths are analyzed for the mineral low albite. Under these conditions additional complications in the spin-lock behavior of the quadrupolar nucleus and in the cross-polarization process were found experimentally and are examined in detail. A step-by-step procedure for optimizing cross-polarization from the central transition of a quadrupolar nucleus to a spin-1/2 nucleus is described. Significant enhancement of {sup 29}Si NMR sensitivity and several applications are demonstrated. 50 refs., 8 figs., 4 tabs.

  13. A Non-radial Eruption in a Quadrupolar Magnetic Configuration with a Coronal Null

    NASA Astrophysics Data System (ADS)

    Sun, Xudong; Hoeksema, J. Todd; Liu, Yang; Chen, Qingrong; Hayashi, Keiji

    2012-10-01

    We report one of the several homologous non-radial eruptions from NOAA active region (AR) 11158 that are strongly modulated by the local magnetic field as observed with the Solar Dynamic Observatory. A small bipole emerged in the sunspot complex and subsequently created a quadrupolar flux system. Nonlinear force-free field extrapolation from vector magnetograms reveals its energetic nature: the fast-shearing bipole accumulated ~2 × 1031 erg free energy (10% of AR total) over just one day despite its relatively small magnetic flux (5% of AR total). During the eruption, the ejected plasma followed a highly inclined trajectory, over 60° with respect to the radial direction, forming a jet-like, inverted-Y-shaped structure in its wake. Field extrapolation suggests complicated magnetic connectivity with a coronal null point, which is favorable of reconnection between different flux components in the quadrupolar system. Indeed, multiple pairs of flare ribbons brightened simultaneously, and coronal reconnection signatures appeared near the inferred null. Part of the magnetic setting resembles that of a blowout-type jet; the observed inverted-Y structure likely outlines the open field lines along the separatrix surface. Owing to the asymmetrical photospheric flux distribution, the confining magnetic pressure decreases much faster horizontally than upward. This special field geometry likely guided the non-radial eruption during its initial stage.

  14. Quantum simulation of interaction blockade in a two-site Bose–Hubbard system with solid quadrupolar crystal

    NASA Astrophysics Data System (ADS)

    Nie, Xinfang; Li, Jun; Cui, Jiangyu; Luo, Zhihuang; Huang, Jiahao; Chen, Hongwei; Lee, Chaohong; Peng, Xinhua; Du, Jiangfeng

    2015-05-01

    The Bose–Hubbard model provides an excellent platform for exploring exotic quantum coherence. Interaction blockade is an important fundamental phenomenon in the two-site Bose–Hubbard system (BHS), which gives a full quantum description for the atomic Bose–Josephson junction. Using the analogy between the two-site BHS and the quadrupolar nuclear magnetic resonance (NMR) crystal, we experimentally simulate a two-site Bose–Hubbard system in a NMR quantum simulator composed of the quadrupolar spin-3/2 sodium nuclei of a NaNO3 single crystal, and observe the interesting phenomenon of interaction blockade via adiabatic dynamics control. To our best knowledge, this is the first experimental implementation of the quantum simulation of the interaction blockade using quadrupolar nuclear system. Our work exhibits important applications of quadrupolar NMR in the quantum information science, i.e. a spin-3/2 system can be used as a full 2-qubit su(4) system, if the quadrupole moment is not fully averaged out by fast tumbling in the liquid phase.

  15. Complete description of the interactions of a quadrupolar nucleus with a radiofrequency field. Implications for data fitting.

    PubMed

    Spencer, T Leigh; Goward, Gillian R; Bain, Alex D

    2013-06-01

    We present a theory, with experimental tests, that treats exactly the effect of radiofrequency (RF) fields on quadrupolar nuclei, yet retains the symbolic expressions as much as possible. This provides a mathematical model of these interactions that can be easily connected to state-of-the-art optimization methods, so that chemically-important parameters can be extracted from fits to experimental data. Nuclei with spins >1/2 typically experience a Zeeman interaction with the (possibly anisotropic) local static field, a quadrupole interaction and are manipulated with RF fields. Since RF fields are limited by hardware, they seldom dominate the other interactions of these nuclei and so the spectra show unusual dependence on the pulse width used. The theory is tested with (23)Na NMR nutation spectra of a single crystal of sodium nitrate, in which the RF is comparable with the quadrupole coupling and is not necessarily on resonance with any of the transitions. Both the intensity and phase of all three transitions are followed as a function of flip angle. This provides a more rigorous trial than a powder sample where many of the details are averaged out. The formalism is based on a symbolic approach which encompasses all the published results, yet is easily implemented numerically, since no explicit spin operators or their commutators are needed. The classic perturbation results are also easily derived. There are no restrictions or assumptions on the spin of the nucleus or the relative sizes of the interactions, so the results are completely general, going beyond the standard first-order treatments in the literature. PMID:23611427

  16. Segmental order in a uniaxially constrained polydimethylsiloxane network

    E-print Network

    Paris-Sud XI, Université de

    L-763 Segmental order in a uniaxially constrained polydimethylsiloxane network : a deuterium of a polydimethylsiloxane model network exhibit quadrupolar doublets under both elongation and compression. Experiments polydimethylsiloxane network in an uniaxial stress for both elongation and compression. 2. Experimental. - 2. 1 SAMPLES

  17. The Effect of Tidal Friction and Quadrupolar Distortion on Orbits of Stars or Planets in Hierarchical Triple systems

    NASA Astrophysics Data System (ADS)

    Kiseleva, L. G.; Eggleton, P. P.

    In hierarchical triple stars, such as lambda Tau and beta Per the combination of a) fluctuating eccentricity due to the third body and b) tidal friction, mainly within the close pair, which tries to remove such fluctuations, can lead to potentially large but slow secular changes in orbital parameters. We model the orbits of both the above systems using a force law which includes a combination of point-mass gravity, quadrupolar distortion of each star by the other two, and a dissipative tidal-friction term. For lambda Tau we find a preferred model where expansion of the inner orbit due to mass transfer on a nuclear timescale is balanced by contraction because tidal friction transfers angular momentum from the inner to the outer orbit. In beta Per, the two orbits are nearly orthogonal (i=100 deg), and the effect of the third star would periodically increase the inner eccentricity up to nearly unity if we neglect the effects of quadrupolar distortion and tidal friction. In fact, in beta Per quadrupolar distortion alone can almost completely suppress the inner eccenticity fluctuations. In a hypothetcal zero-age state of this system, when the inner binary can be supposed to be well-detached, we find large fluctuations in eccentricity which, on being damped by tidal friction, lead to shrinkage of the inner orbit on a surprisingly short timescale. However, the shrinkage is halted by the fact that as the inner pair becomes closer they become more distorted: this quadrupolar distortion leads to apsidal motion which prevents further large fluctuations in eccentricity. In hypothetical cases of nearly orthogonal triple systems with one component of the close pair being a Jupiter-like planet, the combined effect of quadrupolar distortion and tidal friction may reduce the fluctuations of the inner eccentricity, and in some cases the Jupiter orbit can in principle be shrunk quite drastically over a suitably long interval of time. This is potentially important for the long-term evolution.

  18. Nonlinear Dependence Observed in Quadrupolar Collective Excitation of a Trapped BEC

    NASA Astrophysics Data System (ADS)

    Fritsch, A. R.; Tavares, P. E. S.; Bahrami, A.; Tonin, Y. R.; Henn, E. A. L.; Bagnato, V. S.; Telles, G. D.

    2015-05-01

    We report the experimental observation of the collective excitations induced in a magnetically trapped ^{87} Rb Bose-Einstein condensate. Low-lying mode excitations were studied by tracking the condensate's center-of-mass displacement, and its aspect ratio as a function of the hold time in the trap. We were able to partially control the modes onset by modulating the amplitude of the additional field gradient used to excite the BEC. The measured excitation frequencies were found to be in good agreement with the literature. We have also found that the modulation amplitude was able to change the phase of the center-of-mass oscillation. Finally, an interesting, nonlinear dependence was observed on the condensate aspect ratio as a function of the perturbing amplitude which induces the quadrupolar mode.

  19. Dipolar and Quadrupolar Magnetic Field Evolution over Solar Cycles 21, 22, and 23

    NASA Astrophysics Data System (ADS)

    DeRosa, M. L.; Brun, A. S.; Hoeksema, J. T.

    2011-08-01

    Time series of photospheric magnetic field maps from two observatories, along with data from an evolving surface-flux transport model, are decomposed into their constituent spherical harmonic modes. The evolution of these spherical harmonic spectra reflect the modulation of bipole emergence rates through the solar activity cycle, and the subsequent dispersal, shear, and advection of magnetic flux patterns across the solar photosphere. In this article, we discuss the evolution of the dipolar and quadrupolar modes throughout the past three solar cycles (Cycles 21-23), as well as their relation to the reversal of the polar dipole during each solar maximum, and by extension to aspects of the operation of the global solar dynamo.

  20. Electrophoretic mobility without charge driven by quadrupolar polarization of the nanoparticle/water interface

    E-print Network

    Matyushov, Dmitry V

    2012-01-01

    Quadrupolar polarization of the interfacial water layer, typically found for water at contact with hydrophobic solutes, couples with the uniform external field to produce the force acting on a suspended particle. This force exists even in the absence of a net particle charge and its direction is consistent with an effectively negative surface charge. The surface charge density scales as $R^{-2}$ with the particle radius $R$, and the corresponding contribution to the $\\zeta$-potential scales as $R^{-1}$. The charge density and $\\zeta$-potential are consistent with the values typically reported for oil drops and bubbles in water at $R\\simeq 3-10$ nm, but decay below those values for larger particles. The study indicates that electrophoretic mobility without charge is possible, but is limited to relatively small particles a few nanometers in size.

  1. Spin-driven bond order in a (1)/(5)-magnetization plateau phase in the triangular lattice antiferromagnet CuFeO2

    NASA Astrophysics Data System (ADS)

    Nakajima, Taro; Terada, Noriki; Mitsuda, Setsuo; Bewley, Robert

    2013-10-01

    We have investigated spin-wave excitations in a magnetic-field-induced 1/5-magnetization plateau phase in the triangular lattice antiferromagnet CuFeO2 (CFO), by means of inelastic neutron-scattering measurements under applied magnetic fields of up to 13.4 T. Comparing the observed spectra with the calculations in which spin-lattice coupling effects for the nearest-neighbor exchange interactions are taken into account, we have determined the Hamiltonian parameters in the field-induced 1/5-plateau phase, which directly show that CFO exhibits a bond order associated with the magnetic structure in this phase.

  2. Relaxation of spin quantum number S=3/2 under multiple-pulse quadrupolar echoes

    NASA Astrophysics Data System (ADS)

    van der Maarel, J. R. C.

    1991-04-01

    The time evolution of the spin S=3/2 density operator due to relaxation in the presence of a sequence of (?/2) pulses has been calculated using perturbation theory in an interaction representation in which no external time-dependent rf fields occur. It is shown that the relaxation under the effect of the pulse train is similar to T1? relaxation. If the magnetization is sampled between the pulses, outside extreme narrowing conditions the observed signal is characterized by a biexponential decay. The amplitude ratio of the fast and slowly relaxing component equals 0.8:0.2. The rate of the fast relaxing component is sensitive to the pulse cycle time in the presence of slowly fluctuating electric-field gradients. A full expression of the relevant spectral density function valid for (?/2) pulses with arbitrary pulse width has been derived. In this derivation, the processes involved in determining the loss of correlation of the quadrupolar interaction are assumed to be independent and characterized by exponential correlation functions. Due to relaxation under the effect of the (?/2) pulse train triple-quantum coherences may be excited. The latter coherences can be monitored by applying an additional coherence transfer pulse after the pulse train. The relaxation of sodium in an ion exchange resin in the presence of the (?/2) pulse sequence has experimentally been studied and agrees with the theoretical analysis.

  3. DFT-D study of 14N nuclear quadrupolar interactions in tetra-n-alkyl ammonium halide crystals.

    PubMed

    Dib, Eddy; Alonso, Bruno; Mineva, Tzonka

    2014-05-15

    The density functional theory-based method with periodic boundary conditions and addition of a pair-wised empirical correction for the London dispersion energy (DFT-D) was used to study the NMR quadrupolar interaction (coupling constant CQ and asymmetry parameter ?Q) of (14)N nuclei in a homologous series of tetra-n-alkylammonium halides (C(x)H(2x+1))4N(+)X(-) (x = 1-4), (X = Br, I). These (14)N quadrupolar properties are particularly challenging for the DFT-D computations because of their very high sensitivity to tiny geometrical changes, being negligible for other spectral property calculations as, for example, NMR (14)N chemical shift. In addition, the polarization effect of the halide anions in the considered crystal mesophases combines with interactions of van der Waals type between cations and anions. Comparing experimental and theoretical results, the performance of PBE-D functional is preferred over that of B3LYP-D. The results demonstrated a good transferability of the empirical parameters in the London dispersion formula for crystals with two or more carbons per alkyl group in the cations, whereas the empirical corrections in the tetramethylammonium halides appeared to be inappropriate for the quadrupolar interaction calculation. This is attributed to the enhanced cation-anion attraction, which causes a strong polarization at the nitrogen site. Our results demonstrated that the (14)N CQ and ?Q are predominantly affected by the molecular structures of the cations, adapted to the symmetry of the anion arrangements. The long-range polarization effect of the surrounding anions at the target nitrogen site becomes more important for cells with lower spatial symmetry. PMID:24758512

  4. Magnetic Hyperfine Interactions and Electric Quadrupolar Coupling in Alloys of Iron with the Alpha-Manganese Structure

    Microsoft Academic Search

    C. W. Kimball; Walter C. Phillips; M. V. Nevitt; R. S. Preston

    1966-01-01

    The Mössbauer technique has been used to investigate the magnetic hyperfine field and electric quadrupolar coupling at Fe nuclei in chi-phase ternary alloys and in antiferromagnetic MnFe alloys having the alpha-Mn structure. Alloys with 5, 10, 20, and 30 at.% Fe in alpha-Mn and the chi-phase alloys chi(V30Si20Fe50), chi(Ti17Cr24Fe59), and chi(Mo17Cr21Fe62) were examined at 4, 77, and 300°K. The data

  5. An analysis of the magic echo and solid echo sequence for quadrupolar echo spectroscopy of spin I = 1 nuclei by average Hamiltonian theory

    NASA Astrophysics Data System (ADS)

    Mananga, E. S.; Roopchand, R.; Rumala, Y. S.; Boutis, G. S.

    2008-03-01

    This work focuses on analyzing the dynamics of spin I = 1 nuclei evolving under a simple two pulse echo cycle and a magic echo cycle by average Hamiltonian theory. The work highlights how spectral artifacts introduced by finite pulse widths can be removed by cycling the phases of the receiver and transmitter in a well defined way. In addition, it is shown that a magic echo cycle can refocus both the quadrupolar interaction together with any offset Hamiltonian. Due to higher convergence in the Magnus expansion magic echo based quadrupolar echo spectroscopy outperforms the conventional two pulse echo sequence.

  6. Modeling Dipolar and Quadrupolar Defect Structures generated by Chiral Islands in Freely-Suspended Liquid Crystal Films

    E-print Network

    N. M. Silvestre; P. Patricio; M. M. Telo da Gama; A. Pattanaporkrattana; C. S. Park; J. E. Maclennan; N. A. Clark

    2009-04-17

    We report a detailed theoretical analysis of novel quadrupolar interactions observed between islands, which are disk-like inclusions of extra layers, floating in thin, freely suspended smectic C liquid crystal films. Strong tangential anchoring at the island boundaries result in a strength +1 chiral defect in each island and a companion -1 defect in the film, these forming a topological dipole. While islands of the same handedness form linear chains with the topological dipoles pointing in the same direction, as reported in the literature, islands with different handedness form compact quadrupolar structures with the associated dipoles pointing in opposite directions. The interaction between such heterochiral island--defect pairs is complex, with the defects moving to minimize the director field distortion as the distance between the islands changes. The details of the inter-island potential and the trajectories of the -1 defects depend strongly on the elastic anisotropy of the liquid crystal, which can be modified in the experiments by varying the material chirality of the liquid crystal. A Landau model that describes the energetics of freely mobile defects is solved numerically to find equilibrium configurations for a wide range of parameters.

  7. On the determination of the orientational probability distribution of water in heterogeneous systems from 2H and 17O quadrupolar splittings

    NASA Astrophysics Data System (ADS)

    Wong, Tuck C.; Hakala, Marja-Riitta

    1985-08-01

    2H and 17O quadrupolar splittings of water in a lyotropic mesophase were found to render ratios widely different from all previous observations. These new results corroborate the interpretation of Halle and Wennerstrom on the determination of the orientational probability distribution of water in heterogeneous systems from 2H and 17O NMR.

  8. Exploiting Near-Field Coupling between Closely Spaced, Gas-Phase, 10 ( 5 nm Ag Nanoparticles Deposited on NaCl To Observe the Quadrupolar Surface Plasmon Absorption

    E-print Network

    Hitchcock, Adam P.

    Deposited on NaCl To Observe the Quadrupolar Surface Plasmon Absorption David B. Pedersen* and Shiliang Wang of peak absorbance of the surface plasmon resonance (SPR) associated with the nanoparticles. Several of the surface plasmon resonance to longer wavelengths as the interparticle separation decreases is typically

  9. Dynamic Effects on the Powder Line Shapes of Half-Integer Quadrupolar Nuclei: A Solid-State NMR Study of XO4

    E-print Network

    Frydman, Lucio

    of the most established approaches for the detection and molecular-level characterization of dynamics studies were EPR-related zero- field couplings treated with a diffusive stochastic Liouville theory.16Dynamic Effects on the Powder Line Shapes of Half-Integer Quadrupolar Nuclei: A Solid-State NMR

  10. A novel method for determining and improving the quality of a quadrupolar fiber gyro coil under temperature variations.

    PubMed

    Li, Zhihong; Meng, Zhuo; Liu, Tiegen; Yao, X Steve

    2013-01-28

    We introduce a parameter called pointing error thermal sensitivity (PETS) for quantitatively determining the quality of a quadrupolar (QAD) fiber coil under radial temperature variations. We show both analytically and experimentally that the pointing error of a fiber gyro incorporating the fiber coil is linearly proportional to the final radial thermal gradient on the coil, with PETS as the proportional constant. We further show that PETS is linearly proportional to another parameter called effective asymmetric length of the coil. By thermally inducing different radial thermal gradients on the fiber coil and measuring the corresponding pointing errors in a gyroscopic measurement setup, we can confidently determine the PETS of the fiber coil and its associated effective asymmetric length caused by imperfections in coil winding. Consequently, we are able to precisely trim the coil to achieve best thermal performance. PMID:23389233

  11. Effect of isomerism and chain length on electronic structure, photophysics, and sensitizer efficiency in quadrupolar (donor)?-acceptor systems for application in dye-sensitized solar cells.

    PubMed

    Richard, Coralie A; Pan, Zhenxing; Hsu, Hsien-Yi; Cekli, Seda; Schanze, Kirk S; Reynolds, John R

    2014-04-01

    We report on quadrupolar (donor)2-acceptor sensitizers for dye-sensitized solar cells (DSSCs). The acceptor units are based on dithieno[2,3-a:3',2'-c]phenazine and dithieno[3,2-a:2',3'-c]phenazine coupled to thiophene donors. The optoelectronic and photophysical properties of two sets of isomers reveal a rigid structure for linear isomers and an efficient nonradiative decay for branched isomers. These sensitizers were integrated into DSSCs, and the quadrupolar structure is an operational design, as the IPCE reached up to 38% from 400 nm to 600 nm. The lengthening of the donor chain increases the efficiency, demonstrating the appeal of these oligomeric dyes for DSSCs. PMID:24666032

  12. Non-Spherical Source-Surface Model of the Corona and Heliosphere for a Quadrupolar Main Field of the Sun

    NASA Astrophysics Data System (ADS)

    Schulz, M.

    2008-05-01

    Different methods of modeling the coronal and heliospheric magnetic field are conveniently visualized and intercompared by applying them to ideally axisymmetric field models. Thus, for example, a dipolar main B field with its moment parallel to the Sun's rotation axis leads to a flat heliospheric current sheet. More general solar main B fields (still axisymmetric about the solar rotation axis for simplicity) typically lead to cone-shaped current sheets beyond the source surface (and presumably also in MHD models). As in the dipolar case [Schulz et al., Solar Phys., 60, 83-104, 1978], such conical current sheets can be made realistically thin by taking the source surface to be non-spherical in a way that reflects the underlying structure of the Sun's main B field. A source surface that seems to work well in this respect [Schulz, Ann. Geophysicae, 15, 1379-1387, 1997] is a surface of constant F = (1/r)kB, where B is the scalar strength of the Sun's main magnetic field and k (~ 1.4) is a shape parameter. This construction tends to flatten the source surface in regions where B is relatively weak. Thus, for example, the source surface for a dipolar B field is shaped somewhat like a Rugby football, whereas the source surface for an axisymmetric quadrupolar B field is similarly elongated but somewhat flattened (as if stuffed into a pair of co-axial cones) at mid-latitudes. A linear combination of co-axial dipolar and quadrupolar B fields generates a somewhat apple-shaped source surface. If the region surrounded by the source surface is regarded as current-free, then the source surface itself should be (as nearly as possible) an equipotential surface for the corresponding magnetic scalar potential (expanded, for example, in spherical harmonics). More generally, the mean-square tangential component of the coronal magnetic field over the source surface should be minimized with respect to any adjustable parameters of the field model. The solar wind should then flow not quite radially, but rather in a straight line along the outward normal to the source surface, and the heliospheric B field should follow a corresponding generalization of Parker's spiral [Levine et al., Solar Phys., 77, 363-392, 1982]. In this work the above program is implemented for a Sun with an axisymmetric but purely quadrupolar main magnetic field. Two heliospheric current sheets emanate from circular neutral lines at mid-latitudes on the corresponding source surface. However, because the source surface is relatively flattened in regions where these neutral lines appear, the radial component of the heliospheric B field at r ~ 1 AU and beyond is much more nearly latitude-independent in absolute value than one would expect from a model based on a spherical source surface.

  13. Two and Three-dimensional Through-Bond Homonuclear-Heteronuclear Correlation Experiments for Quadrupolar Nuclei in Solid-State NMR

    E-print Network

    Paris-Sud XI, Université de

    for Quadrupolar Nuclei in Solid-State NMR Applied to 27 Al-O-31 P-O-27 Al networks Michaël Deschamps*, Dominique the correlation map characterizing the two 27 Al and the 31 P NMR signatures of 27 Al-O- 31 P-O-27 Al chemically be correlated via the scalar coupling J2 between 27 Al (X) and 31 P (Y) in materials featuring Al-O-P- O

  14. Implementation of controlled phase shift gates and Collins version of Deutsch-Jozsa algorithm on a quadrupolar spin-7/2 nucleus using non-adiabatic geometric phases

    E-print Network

    T. Gopinath; Anil Kumar

    2009-09-22

    In this work Controlled phase shift gates are implemented on a qaudrupolar system, by using non-adiabatic geometric phases. A general procedure is given, for implementing controlled phase shift gates in an 'N' level system. The utility of such controlled phase shift gates, is demonstrated here by implementing 3-qubit Deutsch-Jozsa algorithm on a 7/2 quadrupolar nucleus oriented in a liquid crystal matrix.

  15. Antiferroquadrupolar ordering in a Pr-based superconductor PrIr(2)Zn(20).

    PubMed

    Onimaru, T; Matsumoto, K T; Inoue, Y F; Umeo, K; Sakakibara, T; Karaki, Y; Kubota, M; Takabatake, T

    2011-04-29

    An antiferroquadrupolar ordering at T(Q)=0.11??K has been found in a Pr-based superconductor PrIr(2)Zn(20). The measurements of specific heat and magnetization revealed the non-Kramers ?(3) doublet ground state with the quadrupolar degrees of freedom. The specific heat exhibits a sharp peak at T(Q)=0.11??K. The increment of T(Q) in magnetic fields and the anisotropic B-T phase diagram are consistent with the antiferroquadrupolar ordered state below T(Q). The entropy release at T(Q) is only 20% of Rln2, suggesting that the quadrupolar fluctuations play a role in the formation of the superconducting pairs below T(c)=0.05??K. PMID:21635057

  16. Observation of proximities between spin-1/2 and quadrupolar nuclei: which heteronuclear dipolar recoupling method is preferable?

    PubMed

    Lu, X; Lafon, O; Trébosc, J; Tricot, G; Delevoye, L; Méar, F; Montagne, L; Amoureux, J P

    2012-10-14

    We have recently shown that the dipolar-mediated heteronuclear multiple-quantum coherence (D-HMQC) method allows observing through-space proximities between spin-1/2 ((1)H, (13)C, (31)P...) and quadrupolar ((23)Na, (27)Al...) nuclei. However, the D-HMQC effectiveness depends on the choice of the heteronuclear dipolar recoupling sequence. Here, we compare the efficiency and the robustness of four rotor-synchronized sequences: the symmetry-based ones, R4(1)(2)R4(1)(-2) and its super-cycled version, SR4(1)(2), and two schemes based on simultaneous amplitude and frequency modulations, denoted SFAM-1 and SFAM-2. For the SFAM methods, we point out efficient recoupling conditions that facilitate their experimental optimization and we introduce analytical expressions for the buildup of D-HMQC signal in the case of an isolated spin pair. We show that the main differences between these four sequences lie in the number of adjustable parameters and in their robustness with respect to chemical shift and homonuclear dipolar interactions. The relative performances of these four recoupling sequences are analyzed using average Hamiltonian theory, numerical simulations, and (27)Al-{(31)P} D-HMQC experiments on crystalline aluminophosphate. PMID:23061841

  17. Observation of proximities between spin-1/2 and quadrupolar nuclei: Which heteronuclear dipolar recoupling method is preferable?

    SciTech Connect

    Lu, X.; Lafon, O.; Trebosc, J.; Tricot, G.; Delevoye, L.; Mear, F.; Montagne, L.; Amoureux, J. P. [UCCS (CNRS-8181), Lille North of France University, Villeneuve d'Ascq 59652 (France)

    2012-10-14

    We have recently shown that the dipolar-mediated heteronuclear multiple-quantum coherence (D-HMQC) method allows observing through-space proximities between spin-1/2 ({sup 1}H, {sup 13}C, {sup 31}P Horizontal-Ellipsis ) and quadrupolar ({sup 23}Na, {sup 27}Al Horizontal-Ellipsis ) nuclei. However, the D-HMQC effectiveness depends on the choice of the heteronuclear dipolar recoupling sequence. Here, we compare the efficiency and the robustness of four rotor-synchronized sequences: the symmetry-based ones, R4{sub 1}{sup 2}R4{sub 1}{sup -2} and its super-cycled version, SR4{sub 1}{sup 2}, and two schemes based on simultaneous amplitude and frequency modulations, denoted SFAM-1 and SFAM-2. For the SFAM methods, we point out efficient recoupling conditions that facilitate their experimental optimization and we introduce analytical expressions for the buildup of D-HMQC signal in the case of an isolated spin pair. We show that the main differences between these four sequences lie in the number of adjustable parameters and in their robustness with respect to chemical shift and homonuclear dipolar interactions. The relative performances of these four recoupling sequences are analyzed using average Hamiltonian theory, numerical simulations, and {sup 27}Al-{l_brace}{sup 31}P{r_brace} D-HMQC experiments on crystalline aluminophosphate.

  18. Magnetic dipolar and quadrupolar transitions in two-electron atoms under exponential-cosine-screened Coulomb potential

    NASA Astrophysics Data System (ADS)

    Modesto-Costa, Lucas; Canuto, Sylvio; Mukherjee, Prasanta K.

    2015-03-01

    A detailed investigation of the magnetic dipolar and quadrupolar excitation energies and transition probabilities of helium isoelectronic He, Be2+, C4+, and O6+ have been performed under exponential cosine screened Coulomb potential generated in a plasma environment. The low-lying excited states 1s2:1Se ? 1sns:3Se0, and 1snp:3Po2 (n = 2, 3, 4, and 5) are considered. The variational time-dependent coupled Hartree-Fock scheme has been used. The effect of the confinement produced by the potential on the structural properties is investigated for increasing coupling strength of the plasma. It is noted that there is a gradual destabilization of the energy of the system with the reduction of the ionization potential and the number of excited states. The effect of the screening enhancement on the excitation energies and transition probabilities has also been investigated and the results compared with those available for the free systems and under the simple screened Coulomb potential.

  19. Effect of strongly coupled plasma on the magnetic dipolar and quadrupolar transitions of two-electron ions

    SciTech Connect

    Saha, Jayanta K.; Mukherjee, T. K. [Department of Physics, Narula Institute of Technology, Agarpara, Kolkata 700 109, West Bengal (India); Mukherjee, P. K. [Department of Physics, Ramakrishna Mission Vivekananda University, Belur Math, Howrah 711202, West Bengal (India); Department of Mathematics, Visva Bharati, Santiniketan 731235, West Bengal (India); Fricke, B. [Institute fur Physik, Universitat Kassel, 34109 Kassel (Germany)

    2013-04-15

    Effect of strongly coupled plasma on the excitation energies and transition probabilities for the respective transitions 1s{sup 2}:{sup 1}S{sup e}{yields} 1sns:{sup 3}S{sup e} (n = 2, 3, 4) and 1s{sup 2}:{sup 1}S{sup e}{yields} 1snp:{sup 3}P{sup o} (n = 2, 3, 4) allowed by magnetic dipolar and quadrupolar excitations have been analyzed for the first time for the two-electron ions C{sup 4+}, O{sup 6+}, Ne{sup 8+}, Mg{sup 10+}, Si{sup 12+}, and S{sup 14+}. Time dependent Hatree-Fock theory within variational approach has been adopted for such a study. The effect of surrounding plasma has been treated through the standard Ion-Sphere (IS) model of the plasma where the plasma density is varied systematically from a low value to a pretty high value such that the respective excited states go over to continuum due to such a confinement. The effect of external pressure generated due to plasma confinement on the estimated spectral properties has been analyzed systematically.

  20. An electrorotation technique for measuring the dielectric properties of cells with simultaneous use of negative quadrupolar dielectrophoresis and electrorotation.

    PubMed

    Han, Song-I; Joo, Young-Don; Han, Ki-Ho

    2013-03-01

    This paper presents an effective electrorotation technique for measuring the dielectric properties of cells using a superposed electrical signal, which can simultaneously generate negative quadrupolar dielectrophoretic (nQDEP) force and electrorotational (ROT) torque. The proposed technique involves a three-dimensional (3D) octode, which includes four electrodes arranged in a crisscross pattern on the top and bottom of a microchannel, respectively. A single cell was trapped in the center of the 3D octode by the nQDEP force and simultaneously rotated by the ROT torque. Using the proposed electrorotation technique, ROT spectra of human leukocyte subpopulations (T and B lymphocytes, granulocytes, and monocytes) and metastatic human breast (SkBr3) and lung (A549) cancer cell lines were accurately measured without any disturbance. Torque on the cells generated by the ROT signal was analyzed theoretically based on the single-shell dielectric model for the cells. Furthermore, the dielectric properties of the cells, such as area-specific membrane capacitance and cytoplasm conductivity, were extracted using the measured ROT spectra and the analyzed torque. PMID:23353873

  1. Static and dynamic properties of magnetic systems with competing dipolar and tensorial order parameters

    NASA Astrophysics Data System (ADS)

    Onufrieva, F. P.

    1993-05-01

    A general approach to the study of magnetic systems with competing dipolar and tensorial interactions is developed. The approach extensively uses the relevant properties of the Lie algebra SU( n) ( n=2 S+1). It allows us to find all types of possible ordered phases, to analyze the spectrum of collective excitations and to determine the thermodynamic and dynamic properties. Some applications for magnetic systems with quadrupolar intersite interactions are given.

  2. X-Ray Resonant Scattering as a Direct Probe of Orbital Ordering in Transition-Metal Oxides

    Microsoft Academic Search

    Michele Fabrizio; Massimo Altarelli; Maurizio Benfatto

    1998-01-01

    X-ray resonant scattering at the K-edge of transition-metal oxides is shown to measure the orbital order parameter, supposed to accompany magnetic ordering in some cases. Virtual transitions to the 3d orbitals are quadrupolar in general. In cases with no inversion symmetry, such as V2O3, treated in detail here, a dipole component enhances the resonance. Hence, we argue that the detailed

  3. Dielectrophoretic manipulation of finite sized species and the importance of the quadrupolar contribution.

    PubMed

    Liang, Enzhu; Smith, Rosemary L; Clague, David S

    2004-12-01

    Dielectrophoresis (DEP) is the movement of polarizable species in a nonuniform electric field. DEP is used to attract (positive DEP) to or repel from (negative DEP) regions of high field intensity and is useful for manipulating species, including biological species. Current theoretical and numerical approaches used to predict the response to DEP forces assume that the target species is a point particle; however, in practice, the target species is of finite size, e.g., macromolecules, spores and assay beads. To elucidate the importance of target species size effects, higher order terms in the DEP force multipole expansion must be considered [Electrophoresis 23, 1973 (2002)

  4. Alternative representation for the stability diagram of quadrupole ion traps upon additional quadrupolar excitation.

    PubMed

    Vernier, Arnaud; Chirot, Fabien; Antoine, Rodolphe; Salvador, Arnaud; Charrier, Jean-Philippe; Lemoine, Jerome; Dugourd, Philippe

    2013-01-01

    We present a combined theoretical and experimental study of the stability of ions in a linear ion trap under the application of one or two auxiliary radiofrequency (RF) fields, in order to perform simultaneous resonant excitation/ejection of several different ions. The influence of the amplitude and frequency of the auxiliary field is addressed through the construction of experimental and theoretical stability diagrams. Theoretical diagrams are constructed using the method developed by Konenkov et al. [J. Am. Soc. Mass Spectrom. 13, 597 (2002)]. We propose a new representation of stability diagrams more adapted to the study of auxiliary excitations than the canonical one. Stability regions are represented as a function of the fundamental RF amplitude and of the relative intensity of the excitation. This representation facilitates the monitoring of the evolution of the mass-selectivity of first- and higher-order resonant excitations in the trap, for which an empirical law is derived. We also show that the relative phase shift between the excitation field and the main driving field has a strong influence on the shape of the diagrams. PMID:24308195

  5. Anomalous specific heat behaviour in the quadrupolar Kondo system PrV2Al20

    NASA Astrophysics Data System (ADS)

    Tsujimoto, M.; Matsumoto, Y.; Nakatsuji, S.

    2015-03-01

    We have measured the specific heat of PrV2Al20 at very low temperatures, using high quality single crystals with the residual resistivity ratio ~ 20. The high-quality single crystals exhibit clear double transitions at TQ = 0.75 K and T* = 0.65 K. These transitions are clearer and shift to higher temperature in higher quality single crystals. Besides, there was no hysteresis in those transitions in warming and cooling process of the heat capacity measurements. In the ordered state below T*, the specific heat does not exhibit exponential decay, but T4 power law dependence, indicating the gapless mode associated with the quadrupole and/or octupole degrees of freedom.

  6. FAST TRACK COMMUNICATION: Magnetic field induced confinement-deconfinement transition in graphene quantum dots

    Microsoft Academic Search

    G. Giavaras; P. A. Maksym; M. Roy

    2009-01-01

    Massless Dirac particles cannot be confined by an electrostatic potential. This is a problem for making graphene quantum dots but confinement can be achieved with a magnetic field and here general conditions for confined and deconfined states are derived. There is a class of potentials for which the character of the state can be controlled at will. Then a confinement-deconfinement

  7. Bound states and magnetic field induced valley splitting in gate-tunable graphene quantum dots

    Microsoft Academic Search

    Patrik Recher; Johan Nilsson; Guido Burkard; Björn Trauzettel

    2009-01-01

    The magnetic field dependence of energy levels in gapped single-layer and bilayer graphene quantum dots (QDs) defined by electrostatic gates is studied analytically in terms of the Dirac equation. Due to the absence of sharp edges in these types of QDs, the valley degree of freedom is a good quantum number. We show that its degeneracy is efficiently and controllably

  8. Computational Interpretation of Megagauss-Magnetic-Field-Induced Metallic Surface Plasma Initiation and Evolution

    SciTech Connect

    Lindemuth, Irvin R.; Siemon, Richard E.; Bauer, Bruno S.; Angelova, Milena A.; Atchison, Walter L. [University of Nevada, Reno, Nevada (United States); Los Alamos National Laboratory, Los Alamos, New Mexico (United States)

    2010-11-05

    Numerical simulations of experiments in which plasma is formed on an aluminum surface by megagauss magnetic fields provide the first computational demonstration of a magnetic-field threshold that must be reached for aluminum plasma to begin to form. The computed times of plasma initiation agree reasonably well with the observations across the full range of rod diameters, leading to the conclusion that plasma formation is a thermal process. Computationally, plasma forms first in low-density material that is resistive enough to expand across the magnetic field and yet conductive enough that Ohmic heating exceeds expansion cooling.

  9. Magnetic field induced quantum dot brightening in liquid crystal synergized magnetic and semiconducting nanoparticle composite assemblies.

    PubMed

    Amaral, Jose Jussi; Wan, Jacky; Rodarte, Andrea L; Ferri, Christopher; Quint, Makiko T; Pandolfi, Ronald J; Scheibner, Michael; Hirst, Linda S; Ghosh, Sayantani

    2015-01-14

    The design and development of multifunctional composite materials from artificial nano-constituents is one of the most compelling current research areas. This drive to improve over nature and produce 'meta-materials' has met with some success, but results have proven limited with regards to both the demonstration of synergistic functionalities and in the ability to manipulate the material properties post-fabrication and in situ. Here, magnetic nanoparticles (MNPs) and semiconducting quantum dots (QDs) are co-assembled in a nematic liquid crystalline (LC) matrix, forming composite structures in which the emission intensity of the quantum dots is systematically and reversibly controlled with a small applied magnetic field (<100 mT). This magnetic field-driven brightening, ranging between a two- to three-fold peak intensity increase, is a truly cooperative effect: the LC phase transition creates the co-assemblies, the clustering of the MNPs produces LC re-orientation at atypical low external field, and this re-arrangement produces compaction of the clusters, resulting in the detection of increased QD emission. These results demonstrate a synergistic, reversible, and an all-optical process to detect magnetic fields and additionally, as the clusters are self-assembled in a fluid medium, they offer the possibility for these sensors to be used in broad ranging fluid-based applications. PMID:25354546

  10. Magnetic fluid hyperthermia (MFH): Cancer treatment with AC magnetic field induced excitation of biocompatible superparamagnetic nanoparticles

    Microsoft Academic Search

    Andreas Jordan; Regina Scholz; Peter Wust; Horst Fähling; Roland Felix

    1999-01-01

    The story of hyperthermia with small particles in AC magnetic fields started in the late 1950s, but most of the studies were unfortunately conducted with inadequate animal systems, inexact thermometry and poor AC magnetic field parameters, so that any clinical implication was far behind the horizon.More than three decades later, it was found, that colloidal dispersions of superparamagnetic (subdomain) iron

  11. Magnetic field induced nutation of exciton-polariton polarization in (Cd,Zn)Te crystals

    NASA Astrophysics Data System (ADS)

    Godde, T.; Glazov, M. M.; Akimov, I. A.; Yakovlev, D. R.; Mariette, H.; Bayer, M.

    2013-10-01

    We study the polarization dynamics of exciton-polaritons propagating in sub-mm-thick (Cd,Zn)Te bulk crystals using polarimetric time-of-flight techniques. The application of a magnetic field in Faraday geometry leads to synchronous temporal oscillations of all Stokes parameters of an initially linearly or circularly polarized, spectrally broad optical pulse of 150-fs duration propagating through the crystal. Strong dispersion for photon energies close to the exciton resonance leads to stretching of the optical pulse to a duration of 200-300 ps and enhancement of magneto-optical effects such as the Faraday rotation and the nonreciprocal birefringence. The oscillation frequency of the exciton-polariton polarization increases with magnetic field B, reaching 10 GHz at B˜5 T. Surprisingly, the relative contributions of Faraday rotation and nonreciprocal birefringence undergo strong changes with photon energy, which is attributed to a nontrivial spectral dependence of Faraday rotation in the vicinity of the exciton resonance. This leads to polarization nutation of the transmitted optical pulse in the time domain. The results are well explained by a model that accounts for Faraday rotation and magnetospatial dispersion in zinc-blende crystals. We evaluate the exciton g factor |gexc|=0.2 and the magnetospatial constant |V|=5×10-12 eV cm T-1.

  12. Structure of the photon and magnetic field induced birefringence and dichroism

    E-print Network

    Juan Alberto Beswick; Carlo Rizzo

    2007-02-13

    In this letter we show that the dichroism and ellipticity induced on a linear polarized light beam by the presence of a magnetic field in vacuum can be explained in the framework of the de Broglie's fusion model of a photon. In this model it is assumed that the usual photon is the spin 1 state of a particle-antiparticle bound state of two spin 1/2 fermions. The other S=0 state is referred to as the \\emph{second} photon. On the other hand, since no charged particle neither particles having an electric dipole are considered, no effect is predicted in the presence of electric fields and this model is not in contradiction with star cooling data or solar axion search.

  13. Magnetic field-induced currents in human body in the proximity of power lines

    Microsoft Academic Search

    M. A. Abd-Allah

    2003-01-01

    The paper presents a model for the interaction between humans and ELF magnetic fields generated by power lines. Electric current densities induced due to 50 Hz magnetic fields in a human model placed in a close proximity of 500 kV lines are presented and analyzed. The specific absorption rate (SAR), is investigated for various human model locations under the power

  14. Magnetic field induced rearrangement of the electric field domains in weakly coupled superlattices

    Microsoft Academic Search

    W. H. M. Feu; D. C. Elias; L. A. Cury; G. S. Vieira; M. P. Pires; S. M. Landi; P. L. Souza

    2007-01-01

    We present an investigation of the electric field domain configuration in the sequential tunneling regime in weakly coupled superlattices in the presence of a magnetic field applied parallel to the quantum well layers. We show that, for an applied bias such that two electric field domains are present in the sample, as the magnetic field is increased a succession of

  15. Enhanced magnetic-field-induced optical properties of nanostructured magnetic fluids by doping nematic liquid crystals

    PubMed Central

    2012-01-01

    Ferronematic materials composed of 4-cyano-4?-pentylbiphenyl nematic liquid crystal and oil-based Fe3O4 magnetic fluid were prepared using ultrasonic agitation. The birefringence (?n) and figure of merit of optical properties (Q?=??n/?, where ? is the extinction coefficient) of pure magnetic fluids and the as-prepared ferronematic materials were examined and compared. The figure of merit of optical properties weighs the birefringence and extinction of the materials and is more appropriate to evaluate their optical properties. Similar magnetic-field- and magnetic-particle-concentration-dependent properties of birefringence and figure of merit of optical properties were obtained for the pure magnetic fluids and the ferronematic materials. For the ferronematic materials, the values of Q increase with the volume fractions of nematic liquid crystal under certain fixed field strength and are larger than those of their corresponding pure magnetic fluids at high field region. In addition, the enhancement of Q value increases monotonously with the magnetic field and becomes remarkable when the applied magnetic field is beyond 50 mT. The maximum relative enhanced value of QR exceeds 6.8% in our experiments. The results of this work may conduce to extend the pragmatic applications of nanostructured magnetic fluids in optical field. PMID:22587542

  16. Johannes Richter, Oleg Derzhko and Jorg Schulenburg MAGNETIC-FIELD INDUCED SPIN-PEIERLS INSTABILITY

    E-print Network

    in spin systems driven by magnetoelastic coupling (spin-Peierls instability) observed, e.g., in CuGeO3 [4 magnons with respect to lattice distortions through a magnetoelastic mechanism. We are able to present spin and lattice degrees of freedom. The effect of a magnetoelastic coupling in frustrated

  17. Measurements of the magnetic field induced by a turbulent flow of liquid metala...

    E-print Network

    Wisconsin at Madison, University of

    in Fig. 1, uses two impellers to generate a double-vortex flow of liquid sodium in a 1 m diam spherical vessel. Liquid sodium is used because of its high conductivity =107 -1 m-1 . The choice of a spheri- cal details of the inductive response of a turbulent flow of liquid sodium to an applied magnetic field

  18. Effect of magnetic-field-induced torsion on neutrinos and supernova collapse

    Microsoft Academic Search

    S. Mukherjee

    1996-01-01

    Summary  The neutrino emission from supernova 1987A is being studied by taking into consideration the effect of the magnetic field\\u000a present in the star. The magnetic field generates an anisotropic feature in the local space-time, which in turn leads to the\\u000a cancellation of the axial-vector part of the neutrino current. The interaction cross-section of these neutrinos in the course\\u000a of their

  19. Magnetic-Field-Induced Quantized Conductance Staircase in a Double-Wire Quantum Point Contact

    Microsoft Academic Search

    S. K. Lyo; M. A. Blount; J. S. Moon; J. A. Simmons; J. R. Wendt; J. L. Reno

    1999-01-01

    We show that the low-temperature ballistic conductance G of an electron gas flowing through a narrow tunnel-coupled double-layer quantum wire is sensitively modulated by a magnetic field perpendicular to the wire and in the plane of the layer due to the field-induced anticrossing of the energy-dispersion curves. The magnetic field B creates a V-shaped staircase for the quantized conductance, causing

  20. Bound states and magnetic field induced valley splitting in gate-tunable graphene quantum dots

    NASA Astrophysics Data System (ADS)

    Recher, Patrik; Nilsson, Johan; Burkard, Guido; Trauzettel, Björn

    2009-02-01

    The magnetic field dependence of energy levels in gapped single-layer and bilayer graphene quantum dots (QDs) defined by electrostatic gates is studied analytically in terms of the Dirac equation. Due to the absence of sharp edges in these types of QDs, the valley degree of freedom is a good quantum number. We show that its degeneracy is efficiently and controllably broken by a magnetic field applied perpendicular to the graphene plane. This opens up a feasible route to create well-defined and well-controlled spin and valley qubits in graphene QDs. We also point out the similarities and differences in the spectrum between single-layer and bilayer graphene quantum dots. Striking in the case of bilayer graphene is the anomalous bulk Landau level (LL) that crosses the gap, which results in crossings of QD states with this bulk LL at large magnetic fields in stark contrast to the single-layer case where this LL is absent. The tunability of the gap in the bilayer case allows us to observe different regimes of level spacings directly related to the formation of a pronounced “sombrero” in the bulk band structure. We discuss the applicability of such QDs to control and measure the valley isospin and their potential use for hosting and controlling spin qubits.

  1. Reducing magnetic field induced noise in broad-band seismic recordings

    NASA Astrophysics Data System (ADS)

    Forbriger, Thomas

    2007-04-01

    Seismic broad-band sensors are known to be sensitive to the magnetic field. Magnetic storms and man-made disturbances of the magnetic field can produce significant noise in seismic recordings. I show that variations in the magnetic field translate directly into apparent acceleration of the seismic sensor within the period range from 60 to 1200s for all leaf-spring sensors under investigation. For a Streckeisen STS-1V this is shown even for periods down to 1s. The sensitivity is quantified in magnitude and direction. Both are quite stable over many time windows and signal periods. The sensitivities obtained by linear regression of the acceleration signal on magnetic field recordings during a magnetic storm can effectively be applied to reduce noise in seismic signals. The sensitivity varies in magnitude from sensor to sensor but all are in the range from 0.05 to 1.2ms-2T-1. Seismograms from sensors at Black Forest Observatory (BFO) and stations of the German Regional Seismic Network were investigated. Although these are mainly equipped with leaf-spring sensors, the problem is not limited to this type of instrument. The effect is not observable on the horizontal component STS-1s at BFO while it is significant in the recordings of the vertical STS-1. The main difference between these instruments is the leaf-spring suspension in the vertical component that appears to be the source of the trouble. The suspension springs are made of temperature compensated Elinvar alloys that inherently are ferromagnetic and may respond to the magnetic field in various ways. However, the LaCoste Romberg ET-19 gravimeter at BFO, which uses this material too, does not respond to magnetic storms at a similar magnitude neither do the Invar-wire strainmeters. An active shielding, composed of three Helmholtz coils and a feedback system, is installed at station Stuttgart and provides an improvement of signal-to-noise ratio by almost a factor of 20 at this particular station. The passive Permalloy shielding commonly installed with STS-1V sensors performs similarly well.

  2. Reducing magnetic field induced noise in broad-band seismic recordings

    Microsoft Academic Search

    Thomas Forbriger

    2007-01-01

    Seismic broad-band sensors are known to be sensitive to the magnetic field. Magnetic storms and man-made disturbances of the magnetic field can produce significant noise in seismic recordings. I show that variations in the magnetic field translate directly into apparent acceleration of the seismic sensor within the period range from 60 to 1200s for all leaf-spring sensors under investigation. For

  3. Vacuum current and magnetic field induced by an impenetrable flux tube. Dirichlet problem

    E-print Network

    Volodymyr M. Gorkavenko; Iryna V. Ivanchenko

    2015-05-10

    We consider the vacuum polarization effects created by a finite radius magnetic-flux-carrying tube that is impenetrable for quantum matter. The vacuum polarization depends on the choice of a boundary condition at the edge of the tube. We impose a perfectly reflecting (Dirichlet) boundary condition at the edge of the tube on the charged massive scalar matter field which is quantized outside the tube. We find that a current is induced in the vacuum of the quantized scalar field and it circulates around the tube. As a consequence of the Maxwell equation, a magnetic field strength is also induced in the vacuum and is directed along the tube. We restrict our consideration to a plane case. The behavior of the current and the field strength is comprehensively analyzed. In contrast to the model of singular magnetic filament, magnetic field strength is finite at the edge of the string. Induced vacuum effects strongly depend on the tube radius $r_0$. They are quite negligible at $mr_0 > 1$, whereas it becomes noticeable at $mr_0\\ll1$. Induced vacuum effects are less than in the case of singular magnetic filament.

  4. Particle size and magnetic field-induced optical properties of magnetic fluid nanoparticles.

    PubMed

    Rao, G Narsinga; Yao, Y D; Chen, Y L; Wu, K T; Chen, J W

    2005-09-01

    Magnetite nanoparticles with diameters of 7, 9, and 12 nm have been prepared by a chemical coprecipitation method. The transmission of light through magnetic fluid containing these nanoparticles has been investigated as a function of film thickness with wavelength between 400 and 750 nm, and applied magnetic fields up to 275 Oe. The transmission threshold shifts to the lower wavelength side with decreasing magnetic fluid film thickness as well as the particle size. For a given film thickness, the transmittance increases with increasing magnetic field for films with a particle size of 7 and 9 nm, but decreases in the 12-nm film. This is attributed to the competition between the van der Waals and dipole-dipole interaction. PMID:16241436

  5. Magnetic field induced coherence-incoherence crossover in the interlayer conductivity of a layered organic metal

    Microsoft Academic Search

    M. V. Kartsovnik; P. D. Grigoriev; W. Biberacher; N. D. Kushch

    2009-01-01

    The angle-dependent interlayer magnetoresistance of the layered organic metal\\u000a$\\\\alpha$-(BEDT-TTF)$_2$KHg(SCN)$_4$ is found to undergo a dramatic change from\\u000athe classical conventional behavior at low magnetic fields to an anomalous one\\u000aat high fields. This field-induced crossover and its dependence on the sample\\u000apurity and temperature imply the existence of two parallel channels in the\\u000ainterlayer transport: a classical Boltzmann conductivity

  6. Magnetic field induced coherence-incoherence crossover in the interlayer conductivity of a layered organic metal

    Microsoft Academic Search

    M. V. Kartsovnik; P. D. Grigoriev; W. Biberacher; N. D. Kushch

    2009-01-01

    The angle-dependent interlayer magnetoresistance of the pressurized (to the normal metallic state) layered organic metal alpha-(BEDT-TTF)2KHg(SCN)4 is found to change from the conventional behavior at low magnetic fields to an anomalous one at high fields. The dependence of this field-induced crossover on the sample purity and temperature reveals parallel contribution of the classical Boltzmann and incoherent channels in the interlayer

  7. Magnetic-field-induced alignment-to-orientation conversion in sodium

    Microsoft Academic Search

    X. L. Han; G. W. Schinn

    1991-01-01

    We report a detailed investigation of excited-state alignment-to-orientation conversion in the presence of an external magnetic field. This counterintuitive phenomenon occurs under intermediate-coupling conditions. A weak, linearly polarized, cw laser beam was used to excite and align the Na 3P3\\/2 state in an atomic beam along the z direction. The degree of circular polarization of the resulting fluorescence was detected

  8. Extremely low-frequency magnetic field induces manganese accumulation in brain, kidney and liver of rats.

    PubMed

    Çelik, Mustafa Salih; Güven, Kemal; Akpolat, Veysi; Akda?, Mehmet Zulkuf; Naz?ro?lu, Mustafa; Gül-Güven, Reyhan; Çelik, M Yusuf; Erdo?an, Sait

    2015-06-01

    The aim of the present study was to determine the effects of extremely low-frequency magnetic field (ELF-MF) on accumulation of manganese (Mn) in the kidney, liver and brain of rats. A total of 40 rats were randomly divided into eight groups. Four control groups received 0, 3.75, 15 and 60 mg Mn per kg body weight orally every 2 days for 45 days, respectively. The remaining four groups received same concentrations of Mn and were also exposed to ELF-MF (1.5 mT; 50 Hz) for 4 h for 5 days a week during 45 days. Following the last exposure, kidney, liver and brain were taken from all rats and they were analyzed for Mn accumulation levels using an inductively coupled plasma-optical emission spectrometer. In result of the current study, we observed that Mn levels in brain, kidney and liver were higher in Mn groups than in control groups. Mn levels in brain, kidney and liver were also higher in Mn plus ELF-MF groups than in Mn groups. In conclusion, result of the current study showed that the ELF-MF induced manganese accumulation in kidney, liver and brain of rats. PMID:23448860

  9. Magnetic-field-induced superconductivity in a two-dimensional organic conductor.

    PubMed

    Uji, S; Shinagawa, H; Terashima, T; Yakabe, T; Terai, Y; Tokumoto, M; Kobayashi, A; Tanaka, H; Kobayashi, H

    2001-04-19

    The application of a sufficiently strong magnetic field to a superconductor will, in general, destroy the superconducting state. Two mechanisms are responsible for this. The first is the Zeeman effect, which breaks apart the paired electrons if they are in a spin-singlet (but not a spin-triplet) state. The second is the so-called 'orbital' effect, whereby the vortices penetrate into the superconductors and the energy gain due to the formation of the paired electrons is lost. For the case of layered, two-dimensional superconductors, such as the high-Tc copper oxides, the orbital effect is reduced when the applied magnetic field is parallel to the conducting layers. Here we report resistance and magnetic-torque experiments on single crystals of the quasi-two-dimensional organic conductor lambda-(BETS)2FeCl4, where BETS is bis(ethylenedithio)tetraselenafulvalene. We find that for magnetic fields applied exactly parallel to the conducting layers of the crystals, superconductivity is induced for fields above 17 T at a temperature of 0.1 K. The resulting phase diagram indicates that the transition temperature increases with magnetic field, that is, the superconducting state is further stabilized with magnetic field. PMID:11309610

  10. Magnetic field-induced phase transformation & power harvesting capabilities in magnetic shape memory alloys 

    E-print Network

    Basaran, Burak

    2011-02-22

    Magnetic Shape Memory Alloys (MSMAs) combine shape-change/deformationrecovery abilities of heat driven conventional shape memory alloys (SMA) and magnetic field driven magnetostrictives through martensitic transformation. ...

  11. Magnetic field-induced reversible phase transformation in magnetic shape memory alloys

    NASA Astrophysics Data System (ADS)

    Lagoudas, Dimitris C.; Kiefer, Bjoern; Haldar, Krishnendu

    2009-03-01

    Magnetic Shape Memory Alloys (MSMAs) are promising high-frequency active materials for actuation, sensing, shape control, vibration suppression and energy harvesting applications. The macroscopic functionality of MSMAs originates from the coupled evolution of highly heterogeneous magnetic and elastic domain microstructures. Microstructure dependence of phase transformations in MSMAs introduces internal variables into the model to account for strong effects of domain microstructure processes on MSMA properties and varying elastic and magnetic coupling. Selection of internal variables and their incorporation into constitutive modeling has been done for the problem of field-induced martensite reorientation. Introducing a new internal variable, the austenitic volume fraction, the study of field induced phase transformation between the parent and martensitic phases is performed.

  12. Extremely Low Frequency Magnetic Fields Induce Spermatogenic Germ Cell Apoptosis: Possible Mechanism

    PubMed Central

    Lee, Sang-Kon; Park, Sungman; Gimm, Yoon-Myoung; Kim, Yoon-Won

    2014-01-01

    The energy generated by an extremely low frequency electromagnetic field (ELF-EMF) is too weak to directly induce genotoxicity. However, it is reported that an extremely low frequency magnetic field (ELF-MF) is related to DNA strand breakage and apoptosis. The testes that conduct spermatogenesis through a dynamic cellular process involving meiosis and mitosis seem vulnerable to external stress such as heat, MF exposure, and chemical or physical agents. Nevertheless the results regarding adverse effects of ELF-EMF on human or animal reproductive functions are inconclusive. According to the guideline of the International Commission on Non-Ionizing Radiation Protection (ICNIRP; 2010) for limiting exposure to time-varying MF (1?Hz to 100?kHz), overall conclusion of epidemiologic studies has not consistently shown an association between human adverse reproductive outcomes and maternal or paternal exposure to low frequency fields. In animal studies there is no compelling evidence of causal relationship between prenatal development and ELF-MF exposure. However there is increasing evidence that EL-EMF exposure is involved with germ cell apoptosis in testes. Biophysical mechanism by which ELF-MF induces germ cell apoptosis has not been established. This review proposes the possible mechanism of germ cell apoptosis in testes induced by ELF-MF. PMID:25025060

  13. High-resolution 1H NMR spectra from inhomogeneous fields based on intermolecular multiple-quantum coherences between proton and quadrupolar nuclei

    NASA Astrophysics Data System (ADS)

    Chen, Song; Chen, Ying; Zhong, Jianhui; Chen, Zhong

    2014-11-01

    Based on intermolecular double- and single-quantum coherences between 1H and quadrupolar nuclei, two new pulse sequences with time efficient acquisitions are proposed for high-resolution 1H NMR spectra in inhomogeneous fields. Theoretical expressions for the signal were derived according to the product operator formalism. The proposed methods are applicable to both isolated and J-coupled spin systems, with J-coupling constant rescaling. Experiments on test solutions are performed under non-ideal field conditions to show the applicability of the proposed method. These two sequences are complementary to each other and provide alternative approaches for obtaining high-resolution information in relatively large inhomogeneous fields.

  14. "EASY: A simple tool for simultaneously removing background, deadtime and acoustic ringing in quantitative NMR spectroscopy. Part II: Improved ringing suppression, application to quadrupolar nuclei, cross polarisation and 2D NMR".

    PubMed

    Jaeger, Christian; Hemmann, Felix

    2014-01-01

    A simple experiment for Elimination of Artifacts in NMR SpectroscopY (EASY) was introduced in Part I, and it was shown that NMR probe background signals, spectral distortions due to deadtime effects, and acoustic ringing can be eliminated simultaneously from solid-state NMR spectra. In this Part II, it is shown that acoustic ringing suppression can be improved up to one order of magnitude compared to the original EASY pulse sequence by inserting a delay ? between the two data acquisition scans of the EASY pulse sequence. The achievable ringing suppression depends on the length of this delay and is limited by the spin-lattice relaxation time T1. Furthermore, EASY is considered in conjunction with NMR of quadrupolar nuclei. For strong second-order broadening, EASY can be used to acquire either pure central transition MAS patterns or pure satellite transition NMR spectra. Two further modifications to EASY are introduced. One concerns improved ringing artifact suppression in experiments in which the central transition NMR signal is amplified by Rotor Assisted Population Transfer (RAPT). The second EASY modification enables the acquisition of quantitative NMR spectra if signals with different quadrupole coupling constants are present. In addition, acoustic ringing and (11)B stator signals are removed. Finally, it is demonstrated that the basic idea of EASY for removing ringing artifacts can be realized for heteronuclear one-dimensional and hetero- and homo-nuclear multi-dimensional NMR experiments using extended phase cycling. (15)N{(1)H} CPMAS and (15)N 2D Exchange NMR spectroscopy are considered as examples. PMID:25200102

  15. Fast amplitude-modulated pulse trains with frequency sweep (SW-FAM) in static NMR of half-integer spin quadrupolar nuclei

    NASA Astrophysics Data System (ADS)

    Bräuniger, Thomas; Hempel, Günter; Madhu, P. K.

    2006-07-01

    In solid-state NMR of quadrupolar nuclei with half-integer spin I, fast amplitude-modulated (FAM) pulse trains have been utilised to enhance the intensity of the central-transition signal, by transferring spin population from the satellite transitions. In this paper, the signal-enhancement performance of the recently introduced SW-FAM pulse train with swept modulation frequency [T. Bräuniger, K. Ramaswamy, P.K. Madhu, Enhancement of the central-transition signal in static and magic-angle-spinning NMR of quadrupolar nuclei by frequency-swept fast amplitude-modulated pulses, Chem. Phys. Lett. 383 (2004) 403-410] is explored in more detail for static spectra. It is shown that by sweeping the modulation frequencies linearly over the pulse pairs (SW (1/?)-FAM), the shape of the frequency distribution is improved in comparison to the original pulse scheme (SW (?)-FAM). For static spectra of 27Al (I = 5/2), better signal-enhancement performance is found for the SW (1/?)-FAM sequence, as demonstrated both by experiments and numerical simulations.

  16. The effects of interplay between quadrupolar, dipolar and shielding tensors on magic-angle spinning NMR spectra: shapes of spinning sidebands

    NASA Astrophysics Data System (ADS)

    Davies, Nicola A.; Harris, Robin K.; Olivieri, Alejandro C.

    The shapes of spinning sidebands for 13C magic-angle spinning spectra of solids affected by residual dipolar splittings to 14N are found to be spinning-speed dependent. Simple theory for the case of co-axial tensors indicates that centreband splittings at low spinning speeds yield values of xD (x and D are quadrupolar and dipolar coupling constants respectively) directly. The case of the cyanide carbon resonances for the coordination polymer [&(t)tilde;(CH3)3Pb˜4Ru(CN)6]? is considered in detail. Computer simulations of the sideband bandshapes fit the experimental results well. The quadrupole coupling constants for the three cyanide nitrogen sites lie in the range -1·9 to -2·5 MHz. The shielding anisotropy for the cyanide carbon giving the highest-frequency resonance is found to be ?? = ± 350 ppm.

  17. Heavy-fermion superconductivity in the quadrupole ordered state of PrV2Al20.

    PubMed

    Tsujimoto, Masaki; Matsumoto, Yosuke; Tomita, Takahiro; Sakai, Akito; Nakatsuji, Satoru

    2014-12-31

    PrV2Al20 is a rare example of a heavy-fermion system based on strong hybridization between conduction electrons and nonmagnetic quadrupolar moments of the cubic ?3 ground doublet. Here, we report that a high-quality single crystal of PrV2Al20 exhibits superconductivity at Tc=50??mK in the antiferroquadrupole-ordered state under ambient pressure. The heavy-fermion character of the superconductivity is evident from the specific heat jump of ?C/T?0.3??J/mol?K(2) and the effective mass m*/m0?140 estimated from the temperature dependence of the upper critical field. Furthermore, the high-quality single crystals exhibit double transitions at TQ=0.75??K and T*=0.65??K associated with quadrupole and octupole degrees of freedom of the ?3 doublet. In the ordered state, the specific heat C/T shows a T(3) dependence, indicating the gapless mode associated with the quadrupole order, the octupole order, or both. The strong sensitivity to impurity of the superconductivity suggests unconventional character due to significant quadrupolar fluctuations. PMID:25615375

  18. Dimer-Quadrupolar Quantum Phase Transition in the Quasi-One-Dimensional Heisenberg Model with Biquadratic Interaction

    NASA Astrophysics Data System (ADS)

    Harada, Kenji; Kawashima, Naoki; Troyer, Matthias

    2007-01-01

    The quasi-one-dimensional S=1 Heisenberg antiferromagnet with a biquadratic term is investigated at zero temperature by quantum Monte Carlo simulation. As the magnitude of the inter-chain coupling is increased, the system undergoes a phase transition from a spontaneously dimerized phase to a Néel ordered or spin nematic phase. The numerical results suggest the possibility of an unconventional second-order transition in which the symmetry group characterizing one phase is not a subgroup of the other.

  19. Structural characterisation of phosphate materials: new insights into the spatial proximities between phosphorus and quadrupolar nuclei using the D-HMQC MAS NMR technique.

    PubMed

    Tricot, G; Lafon, O; Trébosc, J; Delevoye, L; Méar, F; Montagne, L; Amoureux, J-P

    2011-10-01

    We show in this article how the spatial proximity between phosphorus and quadrupolar nuclei can be efficiently and easily investigated with the D-HMQC (Dipolar Hetero-nuclear Multiple-Quantum Coherences) NMR technique. Compared to the commonly used CP-HETCOR (Cross-Polarisation HETero-nuclear CORrelation) sequence, the D-HMQC pulse scheme exhibits a higher sensitivity and a better robustness with respect to spinning frequency, electronic shielding and quadrupole interaction, and thus does not require time-consuming and complicated optimisation procedures. The advantages of the D-HMQC are demonstrated in this article through the acquisition of (31)P/S through-space two-dimensional correlation NMR spectra providing unreported structural information on (i) a sodium alumino-silicate glass doped with only 3% of P(2)O(5), (ii) a potassium boro-phosphate glass containing BO(3) and BO(4) groups and (iii) a crystalline zirconium vanado-phosphate. All these systems, representative of the most important mixed phosphate network materials, cannot be correctly investigated with the conventional CP-HETCOR NMR technique. PMID:21853181

  20. Central-transition double-quantum sideband NMR spectroscopy of half-integer quadrupolar nuclei: estimating internuclear distances and probing clusters within multi-spin networks.

    PubMed

    Brinkmann, Andreas; Edén, Mattias

    2014-04-21

    We introduce a strategy to estimate the size of clusters of recoupled homonuclear half-integer quadrupolar nuclei under magic-angle spinning (MAS) conditions, by combining double-quantum (2Q) sideband NMR experiments with an approximate numerical analysis based on the summation of all spin-pairs present over a given radius of the structure. The experiment relies solely on the evolution of homonuclear 2Q coherences (2QC) among the central-transitions (CT) of half-integer spins and is suitable for probing clusters in network structures, such as those encountered in large groups of oxide-based materials. Experimental (11)B, (23)Na and (27)Al NMR results are presented on bis(catecholato)diboron, Na2SO4 and Al2O3, respectively; in each case, the growth of the spin-cluster size was monitored from a series of experiments that employed progressively lengthened 2QC excitation intervals. Our new approach is the first option for probing larger constellations of half-integer spins; it provides similar information as the "multiple-quantum spin counting" experiment, which is well-established for spin-1/2 applications but has hitherto not been demonstrated for half-integer spins undergoing MAS. We also discuss various options for determining the internuclear distance within a (nearly) isolated pair of half-integer spins by comparing the experimental 2Q sideband NMR spectra with results from numerical simulations involving various degrees of approximation. PMID:24603939

  1. Pseudogap, charge order, and pairing density wave at the hot spots in cuprate superconductors

    NASA Astrophysics Data System (ADS)

    Pépin, C.; de Carvalho, V. S.; Kloss, T.; Montiel, X.

    2014-11-01

    We address the timely issue of the presence of charge ordering at the hot spots in the pseudogap phase of cuprate superconductors in the context of an emergent SU(2) symmetry which relates the charge and pairing sectors. Performing the Hubbard-Stratonovich decoupling such that the free energy stays always real and physically meaningful, we exhibit three solutions of the spin-fermion model at hot spots. A careful examination of their stability and free energy shows that, at low temperatures, the system tends towards the coexistence of a charge density wave (CDW) and the composite order parameter made up of the diagonal quadrupolar density wave and pairing fluctuations of K. B. Efetov et al. [Nat. Phys. 9, 442 (2013), 10.1038/nphys2641]. The CDW is sensitive to the shape of the Fermi surface, in contrast to the diagonal quadrupolar order, which is immune to it. SU(2) symmetry within the pseudogap phase also applies to the CDW state, which therefore admits a pairing density p -wave counterpart breaking time-reversal symmetry.

  2. Two novel undulator schemes with quadrupolar focusing for the VUV-FEL at the TESLA test facility

    Microsoft Academic Search

    Yu. M. Nikitina; J. Pflüger

    1996-01-01

    At DESY in Hamburg a free electron laser for the VUV spectral range at 6.4 nm using self amplified spontaneous emission is under construction. It will use the electron beam of the TESLA test facility. One of the main components is an undulator of 30 m length. In order to keep the electron beamsize small over the full undulator length

  3. Orientational ordering studies of fluorinated thermotropic liquid crystals by NMR spectroscopy.

    PubMed

    Calucci, Lucia; Geppi, Marco; Urban, Stanislaw

    2014-10-01

    Fluorinated calamitic thermotropic liquid crystals represent an important class of materials for high-tech applications, especially in the field of liquid crystal displays. The investigation of orientational ordering in these systems is fundamental owing to the dependence of their applications on the anisotropic nature of macroscopic optical, dielectric, and visco-elastic properties. NMR spectroscopy is the most powerful technique for studying orientational order in liquid crystalline systems at a molecular level thanks to the possibility of exploiting different anisotropic observables (chemical shift, dipolar couplings, and quadrupolar coupling) and nuclei ((2)H, (13)C, and (19)F). In this paper, the basic theory and NMR experiments useful for the investigation of orientational order on fluorinated calamitic liquid crystals are reported, and a review of the literature published on this subject is given. Finally, orientational order parameters determined by NMR data are discussed in comparison to those obtained by optical and dielectric anisotropy measurements. PMID:25042970

  4. Ab initio calculations of external-field shifts of the 661-nm quadrupolar clock transition in neutral Ag atoms

    SciTech Connect

    Topcu, Suat; Nasser, Jamil; Daku, Latevi Max Lawson; Fritzsche, Stephan [Laboratoire LIS Versailles, 45 Avenue des Etats-Unis 78035 Versailles (France); Universite de Geneve, Sciences II, CH-1211 Geneva 4 (Switzerland); Institute fuer Physik, Universitaet Kassel, Heinrich-Plett-Str. 40, D-34132 Kassel (Germany)

    2006-04-15

    Frequency shifts of the Ag I 4d{sup 10}5s {sup 2}S{sub 1/2}(F=0,M{sub F}=0) to 4d{sup 9}5s{sup 2} {sup 2}D{sub 5/2}(F{sup '}=2,M{sub F{sup '}}=0) electric-quadrupole transition at 330.6 nm due to external fields are calculated using multiconfigurational self-consistent field methods. As this forbidden transition is free from first order Doppler and Zeeman effects, it is under investigation for the realization of an atomic optical clock. The calculated perturbations are the light shift, the blackbody frequency shift, and the quadratic Zeeman shift. Results show that a total uncertainty of 10{sup -18} could be reach without confining the atoms in a Lamb-Dicke regime in an optical lattice.

  5. Magnetic Field-Induced Spectroscopy of Forbidden Optical Transitions with Application to Lattice-Based Optical Atomic Clocks

    Microsoft Academic Search

    A. V. Taichenachev; V. I. Yudin; C. W. Oates; C. W. Hoyt; Z. W. Barber; L. Hollberg

    2006-01-01

    We develop a method of spectroscopy that uses a weak static magnetic field to enable direct optical excitation of forbidden electric-dipole transitions that are otherwise prohibitively weak. The power of this scheme is demonstrated using the important application of optical atomic clocks based on neutral atoms confined to an optical lattice. The simple experimental implementation of this method---a single clock

  6. A self-monitored theranostic platform based on nanoparticle hyperthermia therapy and alternating magnetic field induced thermoacoustic imaging

    NASA Astrophysics Data System (ADS)

    Feng, Xiaohua; Gao, Fei; Zheng, Yuanjin

    2015-03-01

    Low frequency alternating magnetic field (AMF) had been advocated for thermoacoustic imaging to exploit their inherent deeper penetrations. AMF induced thermoacoustic imaging of magnetic nanoparticles is particularly appealing since the system setup is inherently compatible with nanoparticle hyperthermia therapy. More importantly, owing to the capacity of thermoacoustics for accurate temperature measurement, the integration of AMF induced thermoacoustic imaging into nanoparticle hyperthermia therapy will potentially enable a theranostic platform with imaging guidance and temperature monitoring capabilities. We present herein the AMF induced thermoacoustic process of magnetic nanoparticles experimentally and then investigate furthermore its utilization in temperature monitoring for the nanoparticle hyperthermia. To demonstrate the concept of an integrated theranostic system with minimal overhead, a single coil is used for both the hyperthermia heating and thermoacoustic imaging by interleaving the two processes in time domain. In thermoacoustic imaging mode, the power is set at the amplifier's maximum value whereas to avoid excess heating of the coil in hyperthermia-mode, the power is switched to a lower value and the coil is further cooled by static water. Phantom imaging results of the magnetic nanoparticles and the self temperature monitoring with sub-degree accuracy during hyperthermia process are demonstrated. These proof-of-concept experiments showcase the potential to integrate thermoacoustic imaging with nanoparticle hyperthermia system.

  7. Magnetic-field-induced orientation of superconducting MgB2 crystallites determined by x-ray diffraction

    E-print Network

    Vakni, David

    . The orientation of the crystals with the ab plane parallel to the magnetic field at all temperatures below Tc,13 For a crystal with = H in a field along the c axis, the vortex energy is given by 0/4 ab 2 within a factor= , the theory predicts that the torque should tend to orient crystals with their ab plane parallel

  8. Modulated spin structure responsible for the magnetic-field-induced polarization switching in multiferroic TbMn2O5

    NASA Astrophysics Data System (ADS)

    Lee, Jung-Hoon; Jang, Hyun Myung

    2015-01-01

    Orthorhombic TbMn2O5 (o -TMO ) is a well-known multiferroic manganite with the remarkable property of polarization switching at 3 K under a bias magnetic (H) field along the a axis of P b 21m . To theoretically account for this outstanding observation, we have proposed a modulated spin structure under the saturated bias H field by considering the relative strength of the three relevant exchange parameters in o -TMO . The proposed modulated structure based on density-functional theory (DFT) calculations is described in terms of the spin angle ? between the neighboring M n4 +-Mn3 + spin moments on the a-b plane. We have shown that the computed DFT polarization plotted as a function of ? satisfactorily accounts for the observed H -field-induced polarization switching. We have further theoretically shown that the square of the critical field strength (Hc) needed for the polarization switching is inversely proportional to the degree of the extrinsic magnetoelectric coupling. The computed partial charge density demonstrates that the H -field-induced polarization switching also accompanies with the switching in the sign of the excess valence-electron density.

  9. Current bistability in a weakly coupled multi-quantum well structure: a magnetic field induced ‘memory effect’

    Microsoft Academic Search

    W H M Feu; J M Villas-Bôas; L A Cury; P S S Guimarães; G S Vieira; R Y Tanaka; A Passaro; M P Pires; S M Landi; P L Souza

    2009-01-01

    A study of magnetotunnelling in weakly coupled multi-quantum wells reveals a new phenomenon which constitutes a kind of memory effect in the sense that the electrical resistance of the sample after application of the magnetic field is different from before and contains the information that a magnetic field was applied previously. The change in the electric field domain configuration triggered

  10. Current bistability in a weakly coupled multi-quantum well structure: a magnetic field induced 'memory effect'

    Microsoft Academic Search

    W. H. M. Feu; J. M. Villas-Bôas; L. A. Cury; P. S. S. Guimarães; G. S. Vieira; R. Y. Tanaka; A. Passaro; M. P. Pires; S. M. Landi; P. L. Souza

    2009-01-01

    A study of magnetotunnelling in weakly coupled multi-quantum wells reveals a new phenomenon which constitutes a kind of memory effect in the sense that the electrical resistance of the sample after application of the magnetic field is different from before and contains the information that a magnetic field was applied previously. The change in the electric field domain configuration triggered

  11. Magnetic-field-induced crossover from 2{ital e} to {ital e} periodicity in the superconducting single-electron transistor

    Microsoft Academic Search

    J. G. Lu; J. M. Hergenrother; M. Tinkham

    1996-01-01

    We present extensive experimental data on the gate-charge-periodic current {ital I}({ital Q}{sub {ital o}}) through a single-electron transistor as a function of the applied magnetic field. This device consists of a mesoscopic superconducting island which is coupled to two macroscopic superconducting leads through small tunnel junctions and to a capacitive gate. The behavior of the system exhibits two separate transitions

  12. Under consideration for publication in Geophys. Astrophys. Fluid Dyn. 1 Magnetic field induced by elliptical instability in a

    E-print Network

    Paris-Sud XI, Université de

    & Williamson, 1998). This three-dimensional instability is also often invoked to explain the secondary three-dimensional when their cross-sectional streamlines are not exactly circular but slightly deformed into ellipses (Pierrehumbert, 1986). The instability is generated by a parametric resonance that couples together two inertial

  13. 50 Hz-Sinusoidal magnetic field induced effects on the bioelectric activity of single unit neurone cells

    NASA Astrophysics Data System (ADS)

    Azanza, María. J.; Calvo, Ana C.; del Moral, A.

    2001-05-01

    Neurones recruiting and synchronized bioelectric activity recorded from Helix aspersa brain ganglia, under exposure to 50 Hz sinusoidal magnetic fields of 1-15 mT intensity, is reported. We show recruiting responses from single neurones and the synchronization of pairs of neurones activity. Experimental evidence and model theoretical explanation for the spreading of synchronization are presented.

  14. Observation of a Magnetic-Field-Induced Transition in the Behavior of Extremely Shallow Quantum Well Excitons

    Microsoft Academic Search

    M. Fritze; I. E. Perakis; A. Getter; W. Knox; K. W. Goossen; J. E. Cunningham; S. A. Jackson

    1996-01-01

    Using magnetoabsorption and electroabsorption techniques, we study excitons with binding energy comparable to the depth of GaAs\\/AlGaAs quantum wells. In-plane magnetic fields decrease the exciton linewidth considerably. Without magnetic fields, electroabsorption reveals 3D-like exciton behavior. This broadening persists with magnetic fields along the growth direction, but changes to a redshift for in-plane magnetic fields, reminiscent of 2D-like excitons. We discuss

  15. Magnetic-field-induced effects in the electronic structure of itinerant d- and f-metal systems

    NASA Astrophysics Data System (ADS)

    Grechnev, G. E.

    2009-08-01

    A paramagnetic response of transition metals and itinerant d- and f-metal compounds in an external magnetic field is studied by employing ab initio full-potential LMTO method in the framework of the local spin density approximation. Within this method the anisotropy of the magnetic susceptibility in hexagonal close-packed transition metals is evaluated for the first time. This anisotropy is owing to the orbital Van Vleck-like paramagnetic susceptibility, which is revealed to be substantial in transition-metal systems due to hybridization effects in the electronic structure. It is demonstrated that compounds TiCo, Ni3Al, YCo2, CeCo2, YNi5, LaNi5, and CeNi5 are strong paramagnets close to the quantum critical point. For these systems the Stoner approximation underestimates the spin susceptibility, whereas the calculated field-induced spin moments provide a good description of the large paramagnetic susceptibilities and magnetovolume effects. It is revealed that an itinerant description of hybridized f electrons produces magnetic properties of the compounds CeCo2, CeNi5, UAl3, UGa3, USi3, and UGe3 in close agreement with experiment. In the uranium compounds UX3 the strong spin-orbit coupling together with hybridization effects give rise to peculiar magnetic states in which the field-induced spin moments are antiparallel to the external field, and the magnetic response is dominated by the orbital contribution.

  16. INFLUENCE OF TEMPERATURE DURING THE ELECTRIC AND MAGNETIC FIELD-INDUCED ALTERATION OF CALCIUM RELEASE FROM BRAIN TISSUE, IN VITRO

    EPA Science Inventory

    The release of calcium ions from in vitro preparation of chicken brain-tissue has been used by several investigators to demonstrate the interaction of electric and magnetic (EM) fields with biological systems. or exposures with radiofrequency radiation amplitude modulated at extr...

  17. Extremely low frequency magnetic field induced changes in motor behaviour of gerbils submitted to global cerebral ischemia.

    PubMed

    Rauš, Snežana; Selakovi?, Vesna; Radenovi?, Lidija; Proli?, Zlatko; Jana?, Branka

    2012-03-17

    The purpose of this study was to evaluate behavioural effects of an extremely low frequency magnetic field (ELF-MF) in 3-month-old Mongolian gerbils submitted to global cerebral ischemia. After 10-min occlusion of both common carotid arteries, the gerbils were placed in the vicinity of an electromagnet and continuously exposed to ELF-MF (50Hz, 0.5mT) for 7 days. Their behaviour (locomotion, stereotypy, rotations, and immobility) was monitored on days 1, 2, 4, 7, and 14 after reperfusion for 60min in the open field. It was shown that the 10-min global cerebral ischemia per se induced a significant motor activity increase (locomotion, stereotypy and rotations), and consequently immobility decrease until day 4 after reperfusion, compared to control gerbils. Exposure to ELF-MF inhibited development of ischemia-induced motor hyperactivity during the whole period of registration, but significantly in the first 2 days after reperfusion, when the postischemic hyperactivity was most evident. Motor activity of these gerbils was still significantly increased compared to control ones, but only on day 1 after reperfusion. Our results revealed that the applied ELF-MF (50Hz, 0.5mT) decreased motor hyperactivity induced by the 10-min global cerebral ischemia, via modulation of the processes that underlie this behavioural response. PMID:22119248

  18. Entropy change linked to the magnetic field induced martensitic transformation in a NiMnInCo shape memory alloy

    E-print Network

    ­Sn­X X=Co,Fe,Cr ,15,16 Ni­Mn­Sb,17 Ni­Mn­Sb­Co,18 and Ni­Mn­In­Co.19 The large inverse MCE in these FSMA­Ga alloys close to Heusler Ni2MnGa are the most studied FSMA due to their magneto- strictive behavior which to cool, was reported in Ni­Mn­Sn alloys with S=18 J/kg K at 5 T.6 The inverse MCE is a direct consequence

  19. Magnetic-field-induced dose effects in MR-guided radiotherapy systems: dependence on the magnetic field strength

    Microsoft Academic Search

    A J E Raaijmakers; B W Raaymakers; J J W Lagendijk

    2008-01-01

    Several institutes are currently working on the development of a radiotherapy treatment system with online MR imaging (MRI) modality. The main difference between their designs is the magnetic field strength of the MRI system. While we have chosen a 1.5 Tesla (T) magnetic field strength, the Cross Cancer Institute in Edmonton will be using a 0.2 T MRI scanner and

  20. Magnetic field induced martensitic transformation linked to the arrested austenite in a Ni-Mn-In-Co shape memory alloy

    NASA Astrophysics Data System (ADS)

    Pérez-Landazábal, J. I.; Recarte, V.; Sánchez-Alarcos, V.; Gómez-Polo, C.; Kustov, S.; Cesari, E.

    2011-05-01

    The so-called metamagnetic shape memory alloys transform from a ferromagnetic austenite into a weak magnetic martensitic phase, thus the application of a magnetic field, stabilizing the high magnetization phase, can induce the reverse martensitic transformation. Moreover, the martensitic transformation itself becomes arrested as its temperature range is lowered by the application of high enough magnetic fields. In this work the effect of the magnetic field on a Ni-Mn-In-Co metamagnetic shape memory has been studied by SQUID magnetometry. The arrest of the transformation produced by the field results in metastable states, whose evolution when the field is removed or reduced, follows logarithmic time dependence. The observed behavior is interpreted in terms of the magnetic contribution to the total entropy change associated with the magnetostructural transformation.

  1. 2H-quadrupolar coupling-based analysis of stereochemical and regiochemical memory in the Pd-catalysed allylic alkylation of iso-cinnamyl type substrates employing the chiral monophosphine ligands ‘MOP’ and ‘MAP’

    Microsoft Academic Search

    Laure Gouriou; Guy C Lloyd-Jones; Št?pán Vysko?il; Pavel Ko?ovský

    2003-01-01

    The reaction of iso-cinnamyl acetate with NaC(Me)(CO2Me)2, catalysed by Pd–‘MOP’ (MOP=2-methoxy-2?-diphenylphosphino-1,1?-binaphthalene) is known to proceed with a regiochemical memory effect that results in the predominant generation of the branched alkylation product. The analogous reaction employing ‘MAP’ as ligand (MAP=2-N,N-dimethylamino-2?-diphenylphosphino-1,1?-binaphthalene) proceeds with ‘normal’ regioselectivity to generate predominantly the linear isomer of product. A 2H-NMR based analysis, employing quadrupolar coupling in a

  2. Order Up

    ERIC Educational Resources Information Center

    Gibeault, Michael

    2005-01-01

    Change orders. The words can turn the stomachs of administrators. Horror stories about change orders create fear and distrust among school officials, designers and builders. Can change orders be avoided? If car manufacturers can produce millions of intricately designed vehicles, why can't the same quality control be achieved on a construction…

  3. Soil Orders

    NSDL National Science Digital Library

    Developed by the US Department of Agriculture's Soil Survey Division (SSD), here is a high resolution poster with brief descriptions of the soil orders. Photos of soil profiles accompany descriptions of each order. The soil orders include: Alfisols, Andisols, Aridisols, Entisols, Gelisols, Histosols, Inceptisols, Mollisols, Oxisols, Spodusols, Ultisols, and Vertisols.

  4. Order Nidovirales

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter, entitled "Order Nidovirales", is for inclusion in the Ninth Report of the International Committee on Taxonomy of Viruses (ICTV), to be published as both a single volume text and online. The chapter details the taxonomy of members of the Nidovirus order, including family Arteriviridae o...

  5. Experimental evidence for an optical interference model for vibrational sum frequency generation on multilayer organic thin film systems. II. Consideration for higher order terms.

    PubMed

    O'Brien, Daniel B; Massari, Aaron M

    2015-01-14

    The generalized optical interference model for interfacial contributions to vibrational sum frequency generation (VSFG) spectroscopic signals from organic thin film systems is extended to include a description of optical interferences contained in the thin film bulk response. This is based on electric quadrupolar interactions with the input fields and includes a discussion on possible contribution from the electric quadrupolar polarization. VSFG data from the first of this two part report are analyzed and include effects from higher order responses, for both bulk and higher order interfacial terms. The results indicate that although it is capable of capturing many of the data features, the electric dipole treatment is likely not a complete description of the VSFG intensity data from this system. An analysis based on the signs of the resulting response amplitudes is used to deduce the relative magnitude of the electric dipole and higher order interfacial terms. It is found that the buried interface is closer to satisfying the electric dipole approximation, consistent with smaller field gradients due to closer index matching between the organic thin film and substrate relative to air. The procedure outlined in this work allows for the difficult task of deducing a physical picture of average molecular orientation at the buried interface of a multilayer organic thin film system while including higher order effects. PMID:25591374

  6. Monte Carlo simulations of solute ordering in nematic liquid crystals: Shape anisotropy and quadrupole-quadrupole interactions as orienting mechanisms

    NASA Astrophysics Data System (ADS)

    Polson, James M.; Burnell, E. Elliott

    1997-04-01

    Monte Carlo computer simulations were used to investigate the effects of shape anisotropy and electrostatic interactions as mechanisms for orientational ordering of solutes in nematic liquid crystals. The simulation results were analyzed in terms of two theories of solute ordering which derive mean-field orientational potentials from the intermolecular pair potential. In the calculations, solute and solvent molecular shapes were approximated by hard ellipsoids. Most simulations also incorporated the interaction between point quadrupole moments placed at the centers of the ellipsoids. In the hard-core systems, orientational order parameters and distribution functions were calculated for a collection of different solutes under a variety of conditions. A theory due to Terzis and Photinos [Mol. Phys. 83, 847 (1994)] was found to underestimate the effect of shape anisotropy on orientational ordering drastically. The introduction of an effective solvent packing fraction was unable to improve the predictive power of the theory significantly. The quadrupolar systems were used to investigate a mean-field model for solute ordering which considers an interaction between the solute molecular quadrupole moment with an average electric-field gradient. The simulations indicate that the electric-field gradient sampled by the solute is highly dependent on the properties of the solute, contrary to some experimental evidence. Further, the effects of the intermolecular quadrupolar interactions on orientational ordering and the electric-field gradient were analyzed using a mean-field potential derived here and based on the theory due to Emsley, Palke, and Shilstone [Liq. Cryst. 9, 649 (1991)]. This model was found to provide a qualitatively correct but quantitatively imprecise prediction of orientational ordering.

  7. Influence of Chirality in Ordered Block Copolymer Phases

    NASA Astrophysics Data System (ADS)

    Prasad, Ishan; Grason, Gregory

    2015-03-01

    Block copolymers are known to assemble into rich spectrum of ordered phases, with many complex phases driven by asymmetry in copolymer architecture. Despite decades of study, the influence of intrinsic chirality on equilibrium mesophase assembly of block copolymers is not well understood and largely unexplored. Self-consistent field theory has played a major role in prediction of physical properties of polymeric systems. Only recently, a polar orientational self-consistent field (oSCF) approach was adopted to model chiral BCP having a thermodynamic preference for cholesteric ordering in chiral segments. We implement oSCF theory for chiral nematic copolymers, where segment orientations are characterized by quadrupolar chiral interactions, and focus our study on the thermodynamic stability of bi-continuous network morphologies, and the transfer of molecular chirality to mesoscale chirality of networks. Unique photonic properties observed in butterfly wings have been attributed to presence of chiral single-gyroid networks, this has made it an attractive target for chiral metamaterial design.

  8. Fire Order

    E-print Network

    Baird, John S.

    1956-01-01

    lenses and lips** Garth drained his glass and leaned back in the chair. The colonel stood up and circled the table and filled the glass# , "Did anyone tell you why you1 re here?" he asked# Garth shook his head. "Ho#8 he said. "I just got orders... on each side of the river* The bridge itself has three spans and is made of stone with steel reinforcements. This is the local rainy season* There may­ be high water now, from what we can learn from G-2, but I don't think it's flooding." Garth studied...

  9. Population and coherence transfer in half-integer quadrupolar spin systems induced by simultaneous rapid passages of the satellite transitions: A static and spinning single crystal nuclear magnetic resonance study

    NASA Astrophysics Data System (ADS)

    Schäfer, Hartmut; Iuga, Dinu; Verhagen, Rieko; Kentgens, Arno P. M.

    2001-02-01

    We have recently shown that utilizing double frequency sweeps (DFSs) instead of pulses can lead to increased efficiencies in population and coherence transfer in half-integer quadrupolar spin systems. Cosine modulation of the carrier amplitude corresponds to the simultaneous irradiation of two frequencies symmetrically around the rf-carrier frequency. Convergent or divergent DFSs can be generated by appropriate time-dependent cosine modulation of the rf field. Population and coherence transfer induced by sweeping the modulation frequency through the quadrupolar satellite transitions is investigated in detail. The time dependence of such passages determines the adiabaticity of the transfer processes. Insight into the involved spin dynamics is of utmost importance in the design and optimization of experiments based on amplitude modulation, such as DFS enhanced multiple-quantum magic angle spanning, where multiple to single-quantum conversion is performed by a DFS. Vega and co-workers have provided a theoretical basis of adiabatic coherence transfer in spin-3/2 systems induced by the combined action of simple time independent cosine amplitude modulation (CAM) of the rf field and sample spinning [Madhu et al., J. Chem. Phys. 112, 2377 (2000)]. In our report we will extend this theory to DFS induced adiabatic transfer phenomena in spin-3/2 and spin-5/2 systems. A fully analytical description will be presented covering the whole adiabaticity range resulting in an accurate description of actual experiments. In this context it will be shown that both population and coherence transfer are governed by the same principles and one unique adiabaticity parameter for each pair of spectral satellites. The transfer phenomena derived for spin-3/2 systems will be studied and quantified experimentally for 23Na in a single crystal of NaNO3. In a static and spinning sample the combination with DFS and CAM irradiation will be studied showing the equivalence of the transfer in all these situations. Further we will demonstrate the greater flexibility of a DFS compared to a CAM pulse to manipulate the adiabaticity and thus to maximize the transfer efficiency. Finally, the 27Al resonance in an ?-Al2O3 single crystal will be inspected to demonstrate that the efficiency of DFS-induced population and coherence transfer in spin-5/2 systems depends on the direction of the DFS.

  10. The 4f multipole ordering effect on core-level spectroscopies of Ce intermetallics

    NASA Astrophysics Data System (ADS)

    Sasabe, Norimasa; Tonai, Hironori; Uozumi, Takayuki

    2015-03-01

    The 3d transition metal compounds and 4f rare earth compounds show attractive phenomena, such as superconductivity and Kondo effect, due to strong electron correlations among localized 3d and 4f electrons. Especially, multipole ordering of orbital and/or spin in 4f and 5f compounds is attracting much attention these years. For example, CeB6 is known to show antiferro-quadrupolar (AFQ) ordering below 3.2K. X-ray core-level spectroscopy is an efficient technique to investigate the electronic states of strongly correlated systems. Recent years, experimental techniques have been rapidly developing and, especially, the progress in experimental resolution has enabled us to observe fine spectral features, which were not formerly observed. These advantages will enable us to observe spectral fine features related with the multipole ordering. In this study, we discuss multipole ordering effects on X-ray spectra for CeB6, especially paying attention on the polarization dependence. In order to simulate the electronic state of CeB6 with the multipole ordering, we use an impurity Anderson model including a simplified RKKY interaction.

  11. Order aggressiveness and order book dynamics

    Microsoft Academic Search

    Anthony D. Hall; Nikolaus Hautsch

    2006-01-01

    In this paper, we study the determinants of order aggressiveness and traders’ order submission strategy in an open limit order book market. Applying an order classification scheme, we model the most aggressive market orders, limit orders as well as cancellations on both sides of the market employing a six-dimensional autoregressive conditional intensity model. Using order book data from the Australian

  12. Sensitivity enhancement of the central-transition signal of half-integer spin quadrupolar nuclei in solid-state NMR: Features of multiple fast amplitude-modulated pulse transfer

    NASA Astrophysics Data System (ADS)

    Goswami, Mithun; Madhu, P. K.

    2008-06-01

    Sensitivity enhancement of solid-state NMR spectrum of half-integer spin quadrupolar nuclei under both magic-angle spinning (MAS) and static cases has been demonstrated by transferring polarisation associated with satellite transitions to the central m = -1/2 ? 1/2 transition with suitably modulated radio-frequency pulse schemes. It has been shown that after the application of such enhancement schemes, there still remains polarisation in the satellite transitions that can be transferred to the central transition. This polarisation is available without having to wait for the spin system to return to thermal equilibrium. We demonstrate here the additional sensitivity enhancement obtained by making use of this remaining polarisation with fast amplitude-modulated (FAM) pulse schemes under both MAS and static conditions on a spin-3/2 and a spin-5/2 system. Considerable signal enhancement is obtained with the application of the multiple FAM sequence, denoted as m-FAM. We also report here some of the salient features of these multiple FAM sequences with respect to the nutation frequency of the pulses and the spinning frequency.

  13. Publications Order Form Order by Mail

    E-print Network

    Borenstein, Elhanan

    ;Shipping Information US Postage: fee is $6.00 per order + $2.00 per book ordered Federal Express: chargesPublications Order Form Order by Mail Pay by check or money order payable to University-2100 *Note: Orders may take 7 - 10 days for arrival. Title Forest Pruning and Wood Quality of Western North

  14. Order aggressiveness and order book dynamics

    Microsoft Academic Search

    Anthony D. Hall; Nikolaus Hautsch

    2004-01-01

    In this paper, we study the determinants of order aggressiveness and traders' order submission strategy in an open limit order\\u000a book market. Applying an order classification scheme, we model the most aggressive market orders, limit orders as well as\\u000a cancellations on both sides of the market employing a sixdimensional autoregressive conditional intensity model. Using order\\u000a book data from the Australian

  15. Order aggressiveness in limit order book markets

    Microsoft Academic Search

    Angelo Ranaldo

    2004-01-01

    I examine the information content of a limit order book in a purely order-driven market. I analyze how the state of the limit order book affects a trader's strategy. I develop an econometric technique to study order aggressiveness and provide empirical evidence on the recent theoretical models on limit order book markets. My results show that patient traders become more

  16. MACHINE LEARNING : The Necessity of Order (is order in order ?)

    E-print Network

    Paris-Sud XI, Université de

    - 1 - MACHINE LEARNING : The Necessity of Order (is order in order ?) A. Cornuéjols Laboratoire de to facilitate learning. Yet, when machine learners exhibited sequencing effects, showing that some data sampling is intended to present ideas and directions of research that are currently studied in the machine learning

  17. A model of orientational ordering in phosphatidylcholine bilayers based on conformational analysis of the glycerol backbone region.

    PubMed Central

    Strenk, L M; Westerman, P W; Doane, J W

    1985-01-01

    Molecular and conformational ordering in aqueous multilamellar suspensions of 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) have been examined by deuterium nuclear magnetic resonance (2H NMR) in the liquid crystalline (L alpha) phase. Motionally averaged quadrupolar splittings vQ from six sites in the vicinity of the glycerol backbone have been analyzed by a molecular frame and order matrix approach in which the usual assumption of a freely-rotating molecule is not invoked. By assuming a relatively rigid glycerol backbone region, the six vQ values are found to be consistent with a conformation of the glycerol backbone that is almost identical to that of one of the two structures in crystalline DMPC dihydrate (Pearson, R. H., and I. Pascher, 1979, Nature (Lond.) 281: 499-501). The orientation of the most-ordered axis of the DMPC molecule is found to be tilted at an angle of 27 +/- 2 degrees with respect to the long axis of the sn-1 chain in its extended all trans conformation. The ordering of the most ordered molecular axis with respect to the bilayer normal is expressed by an order parameter of Szz approximately equal to 0.6 +/- 0.1, consistent with values in analogous thermotropic liquid crystals. PMID:4074836

  18. Isotropic-Cholesteric Co-Existence and Magnetic Field-Induced Isotropic-Nematic Transition of Filamentous Bacteriophage FD in Aqueous Suspension

    Microsoft Academic Search

    Jianxin Tang

    1995-01-01

    Isotropic to liquid crystalline phase transition for a lyotropic suspension of geometrically asymmetric macromolecules occurs to a wild class of synthetic polymers and biopolymers. Although in decades statistical mechanical theories have been developed to predict the thermodynamic conditions and the properties of such transition, quantitative comparison with theory has been compounded with complications such as charge, shape, polydispersity in size,

  19. arXiv:cond-mat/0610835v1[cond-mat.str-el]30Oct2006 Optical properties and magnetic field-induced phase transitions in the ferroelectric

    E-print Network

    Cao, Jianming

    and Princeton Materials Institute, Princeton University, Princeton, NJ 08544 7 National High Magnetic Field.20.Ls, 71.20.Be,75.30.Et I. INTRODUCTION Ni3V2O8 is a particularly interesting magnetic material,1 tuning through an unusual commensurate-incommensurate magnetic transition and is facilitated by a soft

  20. High-temperature magnetic-field-induced activation of room-temperature ferromagnetism in Ce1-xNixO2

    NASA Astrophysics Data System (ADS)

    Thurber, A.; Reddy, K. M.; Punnoose, A.

    2007-05-01

    We report room-temperature ferromagnetism in nickel doped ceria (Ce1-xNixO2) powders prepared using the sol-gel process. Magnetometry studies on as-prepared samples reveal a weak ferromagnetic (FM) behavior in the range 00.04, the FM magnetization steadily decreases for increased dopant concentration. The weak FM behavior of the samples improved dramatically after undergoing high-temperature (?500°C) activation in the presence of an external magnetic field (H?1T). The magnitude of the improvement, which was very reproducible, was strongest for 10% Ni doped CeO2 with saturation magnetization Ms increasing by 600 times. Curie temperatures of the activated samples varied in the 597-646K range depending on the Ni concentration and preparation conditions. X-ray diffraction studies did not reveal any noticeable structural changes as a result of the activation process.

  1. Magnetic field induced Raman excitations in Zn1-xCrxTe, Cd1-xCrxTe and Cd1-xCrxSe

    NASA Astrophysics Data System (ADS)

    Lu, X.; Tsoi, S.; Miotkowski, I.; Rodriguez, S.; Ramdas, A. K.; Alawadhi, H.; Pekarek, T. M.

    2007-03-01

    Raman electron paramagnetic resonance(Raman-EPR) of the transitions due to the ?ms=±1 spin-flip of the 3d electrons of Cr^+ in Zn1-xCrxTe and Cd1-xCrxTe are observed at ?PM=g(Cr^+)?BB, g(Cr^+)=2.0041± 0.0095 and 2.0039 ± 0.0093, respectively. Raman lines appear at ?LO± n?PM, n=1,2 and 3, resulting from the strong Fr"Ohlich interaction with LO phonon. The intensity of ?PM can be enhanced through the photo-generation process Cr^2+-> Cr^+; photoluminescence spectra reveal signatures of excitons bound to Cr^+ acceptors in Zn1-xCrxTe. The resonance profile of ?PM shows that the strong resonant enhancement is mediated via an exciton bound to a neutral acceptor. Spin flip Raman scattering (SFRS) at ?SFR from donor-bound electrons in Cd1-xCrxSe, as well as in pure CdSe, are observed, in turn yielding the s-d exchange energy. The magnetization of Cd1-xCrxSe is intermediate between van Vleck and a B2 Brillouin paramagnetism. The linear dependence of the s-d exchange energy as a function of magnetization yields the s-d exchange constant in Cd1-xCrxSe, ?N0=(213.7 ±13) meV.

  2. Spin dynamics in a diluted magnetic semiconductor quantum well studied by pump-probe absorption spectroscopy: Magnetic-field-induced suppression of electron-spin relaxation

    NASA Astrophysics Data System (ADS)

    Murayama, A.; Seo, K.; Nishibayashi, K.; Souma, I.; Oka, Y.

    2006-06-01

    Exciton spin dynamics is studied in a diluted magnetic semiconductor quantum well of Cd0.95Mn0.05Te by pump-probe absorption spectroscopy under magnetic fields. The time dependences of the saturated absorbance for the higher- and lower-energy spin states of heavy-hole (hh) excitons clarify the following exciton-spin relaxation process in magnetic fields: ultrafast hh-spin relaxation with the formation of dark excitons and subsequent electron-spin relaxation. The electron-spin relaxation due to the s-d exchange mechanism involving Mn spins is suppressed in a high magnetic field by field-induced pinning of the Mn spins.

  3. Magnetic-field-induced control of breather dynamics in a single plaquette of Josephson junctions M. V. Fistul, S. Flach, and A. Benabdallah

    E-print Network

    Flach, Sergej

    and various switching phenomena between different resistive states voltage jumps in the I-V curves 2001; published 8 April 2002 We present a theoretical study of inhomogeneous dynamic resistive states the Josephson current oscillations of two resistive junctions. By making use of the rotation wave approximation

  4. Magnetic Field Induced Charged Exciton Studies in a GaAs/Al(0.3)Ga(0.7)As Single Heterojunction

    SciTech Connect

    Kim, Yongmin; Munteanu, F.M.; Perry, C.H.; Reno, J.L.; Rickel, D.G.; Simmons, J.A.

    1999-05-25

    The magnetophotoluminescence (MPL) behavior of a GaAs/Al0.3Ga0.7As single heterojunction has been investigated to 60T. We observed negatively charged singlet and triplet exciton states that are formed at high magnetic fields beyond the {nu}=l quantum Hall state. The variation of the charged exciton binding energies are in good agreement with theoretical predictions. The MPL transition intensities for these states showed intensity variations (maxima and minima) at the {nu}=l/3 and 1/5 fractional quantum Hall (FQH) state as a consequence of a large reduction of electron-hole screening at these filling factors.

  5. Magnetic field-induced shift of the optical band gap in Ni3V2O8 B. S. Holinsworth,1

    E-print Network

    -induced blue shifts of the band gap that are much larger than that of the Zeeman effect in isolation properties. This effect can be as simple as the textbook case of Zeeman splitting of an isolated atom10-induced changes in the optical properties requires reaching beyond traditional mechanisms like the Zeeman effect

  6. Magnetic-field-induced switchable exchange bias in NiFe film on (110) Fe3O4 with a strong uniaxial magnetic anisotropy

    NASA Astrophysics Data System (ADS)

    Dho, Joonghoe

    2015-05-01

    The exchange bias in a soft ferromagnetic NiFe layer coupled with a hard ferrimagnetic Fe3O4 film grown on a (110) SrTiO3 single-crystal substrate was investigated as a function of the switching magnetic field (HS) as a means to control the magnetization direction of the Fe3O4. The sign of the exchange bias was consistent with the sign of HS, indicating that the exchange coupling constant between the NiFe and (110) Fe3O4 layers was positive. Below |HS| = 1 kOe, the hysteresis behavior of the exchange bias of the soft ferromagnetic NiFe resembled the magnetic hysteresis behavior of the hard ferrimagnetic Fe3O4.

  7. Magnetic field-induced phase transformation and variant reorientation in Ni2MnGa and NiMnCoIn magnetic shape memory alloys

    E-print Network

    Karaca, Haluk Ersin

    2009-05-15

    transformation in NiMnCoIn alloys. The ultimate goal of utilizing these mechanisms is to increase the actuation stress levels in magnetic shape memory alloys (MSMAs). Extensive experimental work on magneto-thermo-mechanical (MTM) characterization...

  8. Mössbauer study on the magnetic field-induced insulator-to-metal transition in perovskite EU0.6Sr0.4MnO3

    NASA Astrophysics Data System (ADS)

    Nakamura, Shin; Sato, Masami; Morimoto, Shotaro; Nasu, Saburo; Tsunoda, Yorihiko

    We have investigated the spin dynamics of a distorted perovskite EU0.6Sr0.4MnO3 by means of Mössbauer spectroscopy. Below 70 K the exchange interaction grows gradually, and below 42 K the spins tum into a cluster glass state. The magnetic fieldinduced insulator-to-metal (IM) transition at low temperature is a transition from cluster glass to ferromagnet. The induced metallic phase seems to be still in non-uniform electronic state. On the other hand, at 80 K, just above T c of the induced ferromagnet, a metamagnetic transition was observed.

  9. Large remnant polarization and magnetic field induced destruction of cycloidal spin structure in Bi1-xLaxFeO3 (0 ? x ? 0.2)

    NASA Astrophysics Data System (ADS)

    Yin, L. H.; Yang, J.; Zhao, B. C.; Liu, Y.; Tan, S. G.; Tang, X. W.; Dai, J. M.; Song, W. H.; Sun, Y. P.

    2013-06-01

    We prepared a series of Bi1-xLaxFeO3 (0 ? x ? 0.2) ceramics with a sol-gel method and find that both the magnetization and dielectric constant show an abrupt anomaly near a critical field Hc, which is attributed to the destruction of the cycloidal antiferromagnetic spin structure. The critical field Hc decreases substantially from ˜20 T for the x = 0 sample [Y. F. Popov et al., JETP Lett. 57, 69 (1993)] to ˜2.8 T for the x = 0.17 sample and finally to 0 T for the x = 0.2 sample at room temperature (RT). It is also found that Hc increases with decreasing temperature. The variation of Hc with La substitution and temperature can be ascribed to the change in the magnetic anisotropy and isotropic superexchange interaction, respectively. We have also discussed the magnetodielectric effects in these samples in terms of the Ginzburg-Landau theory and the spin-phonon model. Moreover, increasing the doping level of La to 0.15 greatly improves the RT leakage-current and ferroelectric (FE) properties. A RT square-shaped FE hysteresis loop with remnant polarization (2Pr) as high as ˜64 ?C/cm2 is obtained for the x = 0.15 sample. These results may be important for potential applications in BiFeO3-based magnetoelectric devices.

  10. Solving the viscous hydrodynamics order by order

    E-print Network

    Gao, Jian-Hua

    2014-01-01

    In this paper, we propose a method of solving the viscous hydrodynamics order by order in a derivative expansion. In such method, the zero order solution is just the one of the ideal hydrodynamics. All the other higher order corrections satisfy the same first-order partial differential equations but with different inhomogeneous terms. We therefore argue that our method could be easily extended to any orders. The problem of causality and stability will be released if the gradient expansion is guaranteed. This method might be of great help to both theoretical and numerical calculations of relativistic hydrodynamics.

  11. Universal distribution of magnetic anisotropy of impurities in ordered and disordered nanograins

    NASA Astrophysics Data System (ADS)

    Szilva, A.; Balla, P.; Eriksson, O.; Zaránd, G.; Szunyogh, L.

    2015-04-01

    We examine the distribution of the magnetic anisotropy experienced by a magnetic impurity embedded in a metallic nanograin. As an example of a generic magnetic impurity with a partially filled d shell, we study the case of d1 impurities embedded into ordered and disordered Au nanograins, described in terms of a realistic band structure. Confinement of the electrons induces a magnetic anisotropy that is large, and can be characterized by five real parameters, coupling to the quadrupolar moments of the spin. In ordered (spherical) nanograins, these parameters exhibit symmetrical structures and reflect the symmetry of the underlying lattice, while for disordered grains they are randomly distributed and, for stronger disorder, their distribution is found to be characterized by random matrix theory. As a result, the probability of having small magnetic anisotropies KL is suppressed below a characteristic scale ?E, which we predict to scale with the number of atoms N as ?E˜1 /N3 /2 . This gives rise to anomalies in the specific heat and the susceptibility at temperatures T ˜?E and produces distinct structures in the magnetic excitation spectrum of the clusters that should be possible to detect experimentally.

  12. ASDC Ordering Tool

    Atmospheric Science Data Center

    2014-05-16

    Description:  Search and order data by project, parameter, data set, geographic region and time range. Ordering requires login , searching does not. Projects ... | Tropospheric Chemistry | Field Campaigns All projects Details:  ASDC Ordering Tool ...

  13. Order Statistics and Applications

    E-print Network

    Yorke, James

    Order Statistics and Applications Rosemary Smith #12;Introduction to Order Statistics Unordered Statistics and Observations Ordered Statistics and Observations #12;What kinds of problems are we trying of two order statistics. #12;Formula For We start with the standard formula for expected value Many

  14. Effect of La Substitution in PrIr2Zn20 on the Superconductivity and Antiferro-Quadrupole Order

    NASA Astrophysics Data System (ADS)

    Matsumoto, Keisuke T.; Onimaru, Takahiro; Wakiya, Kazuhei; Umeo, Kazunori; Takabatake, Toshiro

    2015-06-01

    The electrical resistivity ? and the specific heat C of Pr1?xLaxIr2Zn20 (0 ? x ? 1) were measured to study the effect of La substitution in PrIr2Zn20 on the superconducting transition at Tc = 0.05 K and the antiferro-quadrupolar (AFQ) order at TQ = 0.11 K, which occur in a nonmagnetic ?3 doublet ground state. For x = 0.04, a cusp in C(T) due to the AFQ order was observed at TQ = 0.07 K, while the cusp disappeared for x ? 0.09, indicating that the AFQ order rapidly collapses with the dilution of the Pr lattice. On the other hand, in the whole range of 0 ? x ? 1, the superconducting transition to zero resistance was observed. With increasing x, Tc hardly changes up to x = 0.47, above which Tc increases linearly with x. The results indicate a rather weak interplay between Tc and TQ. We have measured the magnetic field variation of Tc to determine the upper critical field of the superconducting state. The estimated effective mass m* for x = 0 is twice larger than that for x = 1, suggesting that moderately strong hybridization between 4f and conduction electrons stabilizes the superconducting state in PrIr2Zn20.

  15. Minimal Orderings Revisited

    SciTech Connect

    Peyton, B.W.

    1999-07-01

    When minimum orderings proved too difficult to deal with, Rose, Tarjan, and Leuker instead studied minimal orderings and how to compute them (Algorithmic aspects of vertex elimination on graphs, SIAM J. Comput., 5:266-283, 1976). This paper introduces an algorithm that is capable of computing much better minimal orderings much more efficiently than the algorithm in Rose et al. The new insight is a way to use certain structures and concepts from modern sparse Cholesky solvers to re-express one of the basic results in Rose et al. The new algorithm begins with any initial ordering and then refines it until a minimal ordering is obtained. it is simple to obtain high-quality low-cost minimal orderings by using fill-reducing heuristic orderings as initial orderings for the algorithm. We examine several such initial orderings in some detail.

  16. ASDC Order Tools

    Atmospheric Science Data Center

    2012-04-17

    ... grid format. ASDC Web Ordering Tools Java Tool Help HTML Tool Help These tools allow users to ... or time range. The ordering tool is available in both Java and HTML versions. Reverb Search Tool Reverb ...

  17. Order of Operations Quiz

    NSDL National Science Digital Library

    This activity allows the user to practice order of operations with addition/subtraction, multiplication/division, exponents, and parentheses. Order of Operations Quiz is one of the Interactivate assessment quizzes.

  18. Order Statistic Experiment

    NSDL National Science Digital Library

    Kyle Siegrist

    This resource consists of a Java applet and expository text. The applet simulates the order statistics of a random sample from a given distribution. The sample size, order, and sampling distribution can be specified.

  19. Engineering Social Order

    Microsoft Academic Search

    Cristiano Castelfranchi

    2000-01-01

    Social Order becomes a major problem in MAS and in computer mediated human interaction. After explaining the notions of Social Order and Social Control, I claim that there are multiple and complementary approaches to Social Order and to its engineering: all of them must be exploited. In computer science one try to solve this problem by rigid formalisation and rules,

  20. FRENCH ORDER WITHOUT ORDER* Gabriel G. B~

    E-print Network

    Paris-Sud XI, Université de

    - gorial Grammar (UCG) (Zeevat, Klein and Calder 1987) as regards word order whereby the directional slash/NP:predNP:post inUCG, wherepre indicates thatthe functor must precede the argument and post that it should follow it can be treated in a framework closely related to UCG but which departs from itin two ways

  1. Multiple ordering in magnetite.

    NASA Technical Reports Server (NTRS)

    Cullen, J. R.; Callen, E. R.

    1973-01-01

    Results of a self-consistent band calculation of the ground-state energy and charge orderings based on a tight-binding scheme in magnetite are presented. They show that below a critical (about 2.2) value of the ratio of interatomic Coulomb energy to bandwidth the lowest energy state has no order. Between this critical value and 2.5, the preferred state is multiply ordered.

  2. Finite Order Statistic Experiment

    NSDL National Science Digital Library

    Kyle Siegrist

    This resource consists of a Java applet and expository text. The applet is a simulation of the experiment of selecting n objects at random from the first m positive integers. The random variables of interest are the order statistics. The applet illustrates the distributions of the order statistics.

  3. Fragments of order

    Microsoft Academic Search

    Aristides Gionis; Teija Kujala; Heikki Mannila

    2003-01-01

    High-dimensional collections of 0--1 data occur in many applications. The attributes in such data sets are typically considered to be unordered. However, in many cases there is a natural total or partial order ≺ underlying the variables of the data set. Examples of variables for which such orders exist include terms in documents, courses in enrollment data, and paleontological sites

  4. Second order Standard Model

    NASA Astrophysics Data System (ADS)

    Espin, Johnny; Krasnov, Kirill

    2015-06-01

    It is known, though not commonly, that one can describe fermions using a second order in derivatives Lagrangian instead of the first order Dirac one. In this description the propagator is scalar, and the complexity is shifted to the vertex, which contains a derivative operator. In this paper we rewrite the Lagrangian of the fermionic sector of the Standard Model in such second order form. The new Lagrangian is extremely compact, and is obtained from the usual first order Lagrangian by integrating out all primed (or dotted) 2-component spinors. It thus contains just half of the 2-component spinors that appear in the usual Lagrangian, which suggests a new perspective on unification. We sketch a natural in this framework SU (2) × SU (4) ? SO (9) unified theory.

  5. Hidden Limit Orders and Liquidity in Limit Order Markets.1

    Microsoft Academic Search

    Sophie Moinas

    Abstract Many limit order markets allow limit order traders to submit “hidden” orders (also called “iceberg” or “undisclosed” orders). Liquidity suppliers thus have the possibility to post a quote and either display none or only a fraction of their order’s quantity to the market. Some recent empirical studies show that such orders represent a large proportion of the market liquidity.

  6. Court-ordered testing.

    PubMed

    1996-05-17

    The Missouri House of Representatives passed legislation allowing anyone to petition the court for court-ordered HIV-antibody testing of any person if the petitioner fears possible HIV infection. Current law only provides court-ordered testing in cases of sex crime. Another House-approved amendment would make it a felony for anyone who tested positive for HIV to engage in prostitution. PMID:11363468

  7. Birth Order and Psychopathology

    PubMed Central

    Risal, Ajay; Tharoor, Hema

    2012-01-01

    Context: Ordinal position the child holds within the sibling ranking of a family is related to intellectual functioning, personality, behavior, and development of psychopathology. Aim: To study the association between birth order and development of psychopathology in patients attending psychiatry services in a teaching hospital. Settings and Design: Hospital-based cross-sectional study. Materials and Methods: Retrospective file review of three groups of patients was carried out. Patient-related variables like age of onset, birth order, family type, and family history of mental illness were compared with psychiatry diagnosis (ICD-10) generated. Statistical Analysis: SPSS 13; descriptive statistics and one-way analysis of variance (ANOVA) were used. Results: Mean age of onset of mental illness among the adult general psychiatry patients (group I, n = 527) was found to be 33.01 ± 15.073, while it was 11.68 ± 4.764 among the child cases (group II, n = 47) and 26.74 ± 7.529 among substance abuse cases (group III, n = 110). Among group I patients, commonest diagnosis was depression followed by anxiety and somatoform disorders irrespective of birth order. Dissociative disorders were most prevalent in the first born child (36.7%) among group II patients. Among group III patients, alcohol dependence was maximum diagnosis in all birth orders. Conclusions: Depression and alcohol dependence was the commonest diagnosis in adult group irrespective of birth order. PMID:24479023

  8. Templated quasicrystalline molecular ordering.

    PubMed

    Smerdon, J A; Young, K M; Lowe, M; Hars, S S; Yadav, T P; Hesp, D; Dhanak, V R; Tsai, A P; Sharma, H R; McGrath, R

    2014-03-12

    Quasicrystals are materials with long-range ordering but no periodicity. We report scanning tunneling microscopy (STM) observations of quasicrystalline molecular layers on 5-fold quasicrystal surfaces. The molecules adopt positions and orientations on the surface consistent with the quasicrystalline ordering of the substrate. Carbon-60 adsorbs atop sufficiently separated Fe atoms on icosahedral Al-Cu-Fe to form a unique quasicrystalline lattice, whereas further C60 molecules decorate remaining surface Fe atoms in a quasi-degenerate fashion. Pentacene (Pn) adsorbs at 10-fold symmetric points around surface-bisected rhombic triacontahedral clusters in icosahedral Ag-In-Yb. These systems constitute the first demonstrations of quasicrystalline molecular ordering on a template. PMID:24528205

  9. Ductile ordered intermetallic alloys.

    PubMed

    Liu, C T; Stiegler, J O

    1984-11-01

    Many ordered intermetallic alloys have attractive high-temperature properties; however, low ductility and brittle fracture limit their use for structural applications. The embrittlement in these alloys is mainly caused by an insufficient number of slip systems (bulk brittleness) and poor grain-boundary cohesion. Recent studies have shown that the ductility and fabricability of ordered intermetallics can be substantially improved by alloying processes and control of microstructural features through rapid solidification and thermomechanical treatments. These results demonstrate that the brittleness problem associated with ordered intermetallics can be overcome by using physical metallurgical principles. Application of these principles will be illustrated by results on Ni(3)Al and Ni(3)V-Co(3)V-Fe(3)V. The potential for developing these alloys as a new class of high-temperature structural materials is discussed. PMID:17774926

  10. ORDER PLACEMENT STRATEGIES IN A PURE LIMIT ORDER BOOK MARKET

    Microsoft Academic Search

    Charles Cao; Oliver Hansch; Xiaoxin Wang

    2008-01-01

    Using order book information from the Australian Stock Exchange (ASX), we examine whether (and to what extent) the order book affects investors' order placement strategies. We find that the top of the book always affects order submissions, cancellations, and amendments, and the rest of the book mostly affects order cancellations and amendments. The previously documented order submission aggressiveness, given a

  11. Birth Order Debate Resolved?

    ERIC Educational Resources Information Center

    Zajonc, R. B.

    2001-01-01

    Critiques Rodgers et al.'s June 2000 research on the relation between birth order and intelligence, which suggests that it is a methodological illusion. Explains how the intellectual environment and the teaching function (whereby older children tutor younger ones) contribute to the growth of intellectual maturity, the first negatively and the…

  12. Tuning order in disorder

    NASA Astrophysics Data System (ADS)

    Ma, Evan

    2015-06-01

    Recent research has revealed considerable diversity in the short-range ordering of metallic glass, identifying favoured and unfavoured local atomic configurations coexisting in an inhomogeneous amorphous structure. Tailoring the population of these local motifs may selectively enhance a desired property.

  13. Education and world order

    Microsoft Academic Search

    Phillip W. Jones

    2007-01-01

    The impact on educational analysis of mainstream international relations (IR) theories is yet to realize its full potential. The problem of education in relation to the construction of world order is considered in relation to core developments in IR theory since the Second World War. In particular, the global architecture of education is seen as a complex web of ideas,

  14. Central Authority and Order

    Microsoft Academic Search

    Emily Erikson; Joseph M. Parent

    2007-01-01

    Strong central authorities are able to effectively manage costly defection, but are unable to adequately address lesser conflicts because of limits to their ability to monitor and enforce. We argue, counterintuitively, that these limitations build coop- eration and trust among subordinates:the limitations contribute to the production of order. First, limits to authority leave space for locally informed decentralized enforce- ment.

  15. Order of Operations Four

    NSDL National Science Digital Library

    2010-01-01

    This game is similar to Connect Four! To earn a piece to place on the board, you must answer an order of operations question (addition / subtraction, multiplication / division, exponents, and parentheses). In this game, you can also choose the time limit, difficulty level, and type of questions.

  16. Ordering Ambiguous Acts

    Microsoft Academic Search

    Ian Jewitt; Sujoy Mukerji

    2011-01-01

    We investigate what it means for one actot be more ambiguous than another. The question is evidently analogous to asking what makes one prospect rikier than another, but beliefs are neither objective nor representatable by a unique probability. Our starting point is an abstract class of preferences constructed to be (strictly) partially ordered by a more ambiguity averse relation. We

  17. Order: Coleoptera Family: Chrysomelidae

    E-print Network

    Liskiewicz, Maciej

    Order: Coleoptera Family: Chrysomelidae Species: Cerotoma trifurcata (Forster) Size: Adults numbers of black spots (Fig. 1). Although some have no spots, most will have four black spots down characteristic is that all have a distinct black triangle behind the prothorax. Eggs are reddish orange ovals

  18. Comparing and Ordering Fractions

    NSDL National Science Digital Library

    2007-12-12

    Use area models to compare and order fractions. Also see a visual representation of the least common denominator of two fractions. With the visual representation of the LCD, this Gizmo can be an introduction to adding and subtracting fractions with unlike denominators.

  19. Land and World Order.

    ERIC Educational Resources Information Center

    Mische, Patricia, Ed.; And Others

    1982-01-01

    The papers in this publication discuss the land and how what happens to the land affects us. The publication is one in a series of monographs that examine the linkages between local and global concerns and explore alternative world futures. Examples of topics discussed in the papers follow. The paper "Land and World Order" examines implications of…

  20. Symmetry and Topological Order

    E-print Network

    Zohar Nussinov; Gerardo Ortiz

    2014-10-22

    We prove sufficient conditions for Topological Quantum Order at both zero and finite temperatures. The crux of the proof hinges on the existence of low-dimensional Gauge-Like Symmetries (that notably extend and differ from standard local gauge symmetries) and their associated defects, thus providing a unifying framework based on a symmetry principle. These symmetries may be actual invariances of the system, or may emerge in the low-energy sector. Prominent examples of Topological Quantum Order display Gauge-Like Symmetries. New systems exhibiting such symmetries include Hamiltonians depicting orbital-dependent spin exchange and Jahn-Teller effects in transition metal orbital compounds, short-range frustrated Klein spin models, and p+ip superconducting arrays. We analyze the physical consequences of Gauge-Like Symmetries (including topological terms and charges), discuss associated braiding, and show the insufficiency of the energy spectrum, topological entanglement entropy, maximal string correlators, and fractionalization in establishing Topological Quantum Order. General symmetry considerations illustrate that not withstanding spectral gaps, thermal fluctuations may impose restrictions on certain suggested quantum computing schemes and lead to "thermal fragility". Our results allow us to go beyond standard topological field theories and engineer systems with Topological Quantum Order.

  1. The Yb2Al1-xMgxSi2 series from a spin fluctuation (x = 0) to a magnetically ordered ground state (x = 1)

    NASA Astrophysics Data System (ADS)

    Shah, K. V.; Bonville, P.; Manfrinetti, P.; Wrubl, F.; Dhar, S. K.

    2009-04-01

    The structural and magnetic properties of Yb2Al1-xMgxSi2 (x = 0, 0.5 and 1), crystallizing in the tetragonal Mo2FeB2-type structure, are reported in this work. Yb2AlSi2 exhibits a Pauli paramagnetic ground state arising due to spin/valence fluctuations induced by a significant Yb 4f conduction band hybridization. High-field magnetization (up to 120 kOe) indicates a nearly temperature-independent susceptibility of 8.6 × 10-3 emu/Yb mol below 10 K. On the other hand, Yb ions in Yb2MgSi2 order antiferromagnetically at a relatively high temperature TN of 9.5 K. The intermediate composition alloy Yb2Al0.5Mg0.5Si2 is a Kondo lattice, antiferromagnet with TN = 5.5 K. The coefficient of the linear term of the electronic heat capacity, ?, of Yb2AlSi2 is found to be 305 mJ mol-1 K-2, indicating a significant electronic mass enhancement due to strong electronic correlations. Below 12 K, an additional contribution to the heat capacity of the form T3lnT is observed. The 170Yb Mössbauer spectra in the ordered state of Yb2MgSi2 indicate a strong coupling of the 4f quadrupolar moment with the magnetic moment through a magneto-elastic coupling.

  2. The Yb(2)Al(1-x)Mg(x)Si(2) series from a spin fluctuation (x = 0) to a magnetically ordered ground state (x = 1).

    PubMed

    Shah, K V; Bonville, P; Manfrinetti, P; Wrubl, F; Dhar, S K

    2009-04-29

    The structural and magnetic properties of Yb(2)Al(1-x)Mg(x)Si(2) (x = 0, 0.5 and 1), crystallizing in the tetragonal Mo(2)FeB(2)-type structure, are reported in this work. Yb(2)AlSi(2) exhibits a Pauli paramagnetic ground state arising due to spin/valence fluctuations induced by a significant Yb 4f conduction band hybridization. High-field magnetization (up to 120 kOe) indicates a nearly temperature-independent susceptibility of 8.6 × 10(-3) emu/Yb mol below 10 K. On the other hand, Yb ions in Yb(2)MgSi(2) order antiferromagnetically at a relatively high temperature T(N) of 9.5 K. The intermediate composition alloy Yb(2)Al(0.5)Mg(0.5)Si(2) is a Kondo lattice, antiferromagnet with T(N) = 5.5 K. The coefficient of the linear term of the electronic heat capacity, ?, of Yb(2)AlSi(2) is found to be 305 mJ mol(-1) K(-2), indicating a significant electronic mass enhancement due to strong electronic correlations. Below 12 K, an additional contribution to the heat capacity of the form T(3)lnT is observed. The (170)Yb Mössbauer spectra in the ordered state of Yb(2)MgSi(2) indicate a strong coupling of the 4f quadrupolar moment with the magnetic moment through a magneto-elastic coupling. PMID:21825437

  3. Mail Order Food Safety

    MedlinePLUS

    ... Administrative Forms Standard Forms Skip Navigation Z7_0Q0619C0JGR010IFST1G5B10H1 Web Content Viewer (JSR 286) Actions ${title} Loading... / Topics / ... Food Handling / Mail Order Food Safety Z7_0Q0619C0JGR010IFST1G5B10H3 Web Content Viewer (JSR 286) Actions ${title} Loading... Z7_ ...

  4. 1.NBT Ordering Numbers

    NSDL National Science Digital Library

    This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: Malik is given a list of numbers: 1 \\ \\ 5 \\ \\ 10 \\ \\ 50 \\ \\ 100 He wants to include the following numbers so all numbers will be listed in order from l...

  5. 3.NF Ordering Fractions

    NSDL National Science Digital Library

    This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: Arrange the fractions in order from least to greatest. Explain your answer with a picture. $\\frac{1}{5}, \\frac{1}{7}, \\frac{1}{3} $ $\\frac{2}{5}, \\frac...

  6. Higher order Bezier circles

    NASA Technical Reports Server (NTRS)

    Chou, Jin

    1993-01-01

    Rational Bezier and B-spline representations of circles have been heavily publicized. However, all the literature assumes the rational Bezier segments in the homogeneous space are both planar and (equivalent to) quadratic. This creates the illusion that circles can only be achieved by planar and quadratic curves. Circles that are formed by higher order rational Bezier curves which are nonplanar in the homogeneous space are shown. The problem of whether it is possible to represent a complete circle with one Bezier curve is investigated. In addition, some other interesting properties of cubic Bezier arcs are discussed.

  7. Localization protected quantum order

    NASA Astrophysics Data System (ADS)

    Nandkishore, Rahul

    2015-03-01

    Many body localization occurs in isolated quantum systems, usually with strong disorder, and is marked by absence of dissipation, absence of thermal equilibration, and a memory of the initial conditions that survives in local observables for arbitrarily long times. The many body localized regime is a non-equilibrium, strongly disordered, non-self averaging regime that presents a new frontier for quantum statistical mechanics. In this talk, I point out that there exists a vast zoo of correlated many body localized states of matter, which may be classified using familiar notions of spontaneous symmetry breaking and topological order. I will point out that in the many body localized regime, spontaneous symmetry breaking can occur even at high energy densities in one dimensional systems, and topological order can occur even without a bulk gap. I will also discuss the phenomenology of imperfectly isolated many body localized systems, which are weakly coupled to a heat bath. I will conclude with a brief discussion of how these phenomena may best be detected in experiments. Collaborators: David Huse, S.L. Sondhi, Arijeet Pal, Vadim Oganesyan, A.C. Potter, Sarang Gopalakrishnan, S. Johri, R.N. Bhatt.

  8. Ordered photonic microstructures

    NASA Astrophysics Data System (ADS)

    Chen, Kevin Ming

    2001-09-01

    This thesis examines novel photonic materials systems possessing order in the atomic, microscopic, and macroscopic dimensional regimes. In the atomic order regime, a structure-property investigation is done for Er2O3 in which the first report of room temperature photoluminescence (PL) is provided. Thin films of the rare earth oxide were deposited via reactive sputtering of Er metal in an Ar/O2 ambient, and subsequently annealed to promote grain growth. Heat treatment consisting of a 650°C followed by 1000°C anneal produces maximum crystallinity as measured by glancing angle x-ray diffraction. These films show characteristic PL at ? = 1.54 ?m. In the microscopic order regime, omnidirectional reflectors and thin film microcavities are demonstrated using sol-gel and solid-state materials. A first demonstration of omnidirectional reflectivity in sol-gel structures was accomplished using a dielectric stack consisting of 12 spin-on SiO 2/TiO2 quarterwave sol-gel films. Similarly, solid-state dielectric stacks consisting of 6 Si/SiO2 sputtered films were used to demonstrate the same principle. Microcavities were formed using solgel structures, producing a low quality factor Q = 35 due to limitations in film thickness control and lossy interfaces from stress-induced cracks. The high index contrast Si/SiO2 microcavities enabled Q ~ 1000 using 17 total layers following hydrogenation of dangling bonds within the amorphous Si films. Combining fabrication processes for the solid-state microcavity and Er2O3 films, a device was fabricated to demonstrate photoluminescence enhancement of an Er2O3 film embedded in a microcavity. The structure consisted of 3-bilayer mirrors on either side of an SiO2/Er2O3/SiO2 cavity. The Q ~ 300 was near the theoretical value for such a structure. At room temperature, PL of Er2O3 was enhanced by a factor of 1000 in the microcavity compared to a single thin film. In the macroscopic order regime, self-assembly of micron- sized SiO 2 and polystyrene latex colloidal particles into 2D crystals is presented. The colloidal assemblies offer a relatively easy processing route for fabrication of photonic bandgap structures. Large (>1 mm diameter) single crystal grains of colloids were formed using controlled evaporation and fluid flow techniques. A novel solution enabling post-processing of the fragile ordered assemblies is presented in which polyelectrolyte multilayers serve as adsorption platforms that anchor the colloidal assemblies. Tailorability of the polyelectrolyte surface properties (charge density, morphology) enables tuning of the colloid adsorption behavior. The polyelectrolyte surface affects colloid adsorption by influencing its surface diffusion. Observations of colloid surface diffusion were made using optical microscopy. Use of polyelectrolytes patterned via microcontact printing enables fabrication of colloid assemblies containing predesigned point and line defects. The patterned polyelectrolyte adsorption template allows placement of colloids in specific geometric arrangement, making possible the realization of sensors or functional photonic bandgap devices such as waveguides or photon traps. Three mechanisms were used to control adsorption: (1)pH of the colloid suspension, which determines the ionization of the uppermost surface of the polyelectrolyte multilayer; (2)ionic strength of the suspension, which determines the extent of charge screening about the colloid and polyelectrolyte; and (3)concentration of added surfactant, which causes charge screening and introduces hydrophobic interactions between the surfactant and polyelectrolyte. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253- 1690.)

  9. Acoustic assisted, field-induced strain in ferromagnetic shape memory alloys

    NASA Astrophysics Data System (ADS)

    Peterson, Bradley W.; Feuchtwanger, Jorge; Chambers, Joshua M.; Bono, David; Hall, Steven R.; Allen, Samuel M.; O'Handley, Robert C.

    2004-06-01

    A technique has been developed that uses acoustic energy to assist a magnetic field in driving twin boundary motion in a NiMnGa single crystal. Acoustic assisted magnetic-field-induced strain has been observed to increase the magnetic-field-induced strain response by up to one order of magnitude. This effect is most pronounced for magnetic field drives near the twin boundary threshold field. Increasing frequency of the acoustic wave input is shown to increase strain up to about 4 kHz after which there is a small decline in FSMA strain for higher frequencies.

  10. Symmetry, shape, and order

    PubMed Central

    Trovato, Antonio; Hoang, Trinh Xuan; Banavar, Jayanth R.; Maritan, Amos

    2007-01-01

    Packing problems have been of great interest in many diverse contexts for many centuries. The optimal packing of identical objects has been often invoked to understand the nature of low-temperature phases of matter. In celebrated work, Kepler conjectured that the densest packing of spheres is realized by stacking variants of the face-centered-cubic lattice and has a packing fraction of ?/(32)?0.7405. Much more recently, an unusually high-density packing of ?0.770732 was achieved for congruent ellipsoids. Such studies are relevant for understanding the structure of crystals, glasses, the storage and jamming of granular materials, ceramics, and the assembly of viral capsid structures. Here, we carry out analytical studies of the stacking of close-packed planar layers of systems made up of truncated cones possessing uniaxial symmetry. We present examples of high-density packing whose order is characterized by a broken symmetry arising from the shape of the constituent objects. We find a biaxial arrangement of solid cones with a packing fraction of ?/4. For truncated cones, there are two distinct regimes, characterized by different packing arrangements, depending on the ratio c of the base radii of the truncated cones with a transition at c*=2?1. PMID:18032605

  11. Valid Orderings of Hyperplane Arrangements

    E-print Network

    Valid Orderings of Hyperplane Arrangements Richard P. Stanley M.I.T. Valid Orderings of Hyperplane from points v Rd . Valid Orderings of Hyperplane Arrangements ­ p. #12;Visible facets P: a d visible no facets are Valid Orderings of Hyperplane Arrangements ­ p. #12;The visibility arrangement aff

  12. Time Ordering in Kicked Qubits

    E-print Network

    L. Kaplan; Kh. Kh. Shakov; A. Chalastaras; M. Maggio; A. L. Burin; J. H. McGuire

    2004-06-23

    We examine time ordering effects in strongly, suddenly perturbed two-state quantum systems (kicked qubits) by comparing results with time ordering to results without time ordering. Simple analytic expressions are given for state occupation amplitudes and probabilities for singly and multiply kicked qubits. We investigate the limit of no time ordering, which can differ in different representations.

  13. Visibility-ordering meshed polyhedra

    Microsoft Academic Search

    Peter L. Williams

    1992-01-01

    A visibility-ordering of a set of objects from some viewpoint is an ordering such that if object a obstructs object b, then b precedes a in the ordering. An algorithm is presented that generates a visibility-ordering of an acyclic convex set of meshed convex polyhedra. This algorithm takes time linear in the size of the mesh. Modifications to this algorithm

  14. Ordinal Data, Ordered Scale Points, and Order Statistics.

    ERIC Educational Resources Information Center

    Vijn, Peter

    1983-01-01

    The use of Bayesian theory to connect ordinal data and ordered scale points with the theory of order statistics is presented. Exact and approximate multivariate and marginal densities for the scale points are derived. (Author/JKS)

  15. A Termination Ordering for Higher Order Rewrite System

    Microsoft Academic Search

    Olav Lysne; Javier Piris

    1995-01-01

    We present an extension of the recursive path ordering for the purposeof showing termination of higher order rewrite systems. Keeping close to the generalpath ordering of Dershowitz and Hoot, we demonstrate the necessary properties ofthe termination functions for our method to apply, thus describe a class of differentorderings. We also give a counterexample to a previously published extension of therecursive

  16. Topology in Ordered Phases

    NASA Astrophysics Data System (ADS)

    Tanda, Satoshi; Matsuyama, Toyoki; Oda, Migaku; Asano, Yasuhiro; Yakubo, Kousuke

    2006-08-01

    I. Topology as universal concept. Optical vorticulture / M. V. Berry. On universality of mathematical structure in nature: topology / T. Matsuyama. Topology in physics / R. Jackiw. Isoholonomic problem and holonomic quantum computation / S. Tanimura -- II. Topological crystals. Topological crystals of NbSe[symbol] / S. Tanda ... [et al.]. Superconducting states on a Möbius strip / M. Hayashi ... [et al.]. Structure analyses of topological crystals using synchrotron radiation / Y. Nogami ... [et al.]. Transport measurement for topological charge density waves / T. Matsuura ... [et al.]. Theoretical study on Little-Parks oscillation in nanoscale superconducting ring / T. Suzuki, M. Hayashi and H. Ebisawa. Frustrated CDW states in topological crystals / K. Kuboki ... [et al.]. Law of growth in topological crystal / M. Tsubota ... [et al.]. Synthesis and electric properties of NbS[symbol]: possibility of room temperature charge density wave devices / H. Nobukane ... [et al.]. How does a single crystal become a Möbius strip? / T. Matsuura ... [et al.]. Development of X-ray analysis method for topological crystals / K. Yamamoto ... [et al.] -- III. Topological materials. Femtosecond-timescale structure dynamics in complex materials: the case of (NbSe[symbol])[symbol]I / D. Dvorsek and D. Mihailovic. Ultrafast dynamics of charge-density-wave in topological crystals / K. Shimatake ... [et al.]. Topology in morphologies of a folded single-chain polymer / Y. Takenaka, D. Baigl and K. Yoshikawa. One to two-dimensional conversion in topological crystals / T. Toshima, K. Inagaki and S. Tanda. Topological change of Fermi surface in Bismuth under high pressure / M. Kasami ... [et al.]. Topological change of 4, 4'-bis[9-dicarbazolyl]-2, 2'-biphenyl (CBP) by international rearrangement / K. S. Son ... [et al.]. Spin dynamics in Heisenberg triangular system VI5 cluster studied by [symbol]H-NMR / Y. Furukawa ... [et al.]. STM/STS on NbSe[symbol] nanotubes / K. Ichimura ...[et al.]. Nanofibers of hydrogen storage alloy / I. Saita ... [et al.]. Synthesis of stable icosahedral quasicrystals in Zn-Sc based alloys and their magnetic properties / S. Kashimoto and T. Ishimasa. One-armed spiral wave excited by eam pressure in accretion disks in Be/X-Ray binaries / K. Hayasaki and A. T. Okazaki -- IV. Topological defects and excitations. Topological excitations in the ground state of charge density wave systems / P. Monceau. Soliton transport in nanoscale charge-density-wave systems / K. Inagaki, T. Toshima and S. Tanda. Topological defects in triplet superconductors UPt3, Sr[symbol]RuO[symbol], etc. / K. Maki ... [et al.]. Microscopic structure of vortices in type II superconductors / K. Machida ... [et al.]. Microscopic neutron investigation of the Abrikosov state of high-temperature superconductors / J. Mesot. Energy dissipation at nano-scale topological defects of high-Tc superconductors: microwave study / A. Maeda. Pressure induced topological phase transition in the heavy Fermion compound CeAl[symbol] / H. Miyagawa ... [et al.]. Explanation for the unusual orientation of LSCO square vortex lattice in terms of nodal superconductivity / M. Oda. Local electronic states in Bi[symbol]Sr[symbol]CaCu[symbol]O[symbol] / A. Hashimoto ... [et al.] -- V. Topology in quantum phenomena. Topological vortex formation in a Bose-Einstein condensate of alkali-metal atoms / M. Nakahara. Quantum phase transition of [symbol]He confined in nano-porous media / K. Shirahama, K. Yamamoto and Y. Shibayama. A new mean-field theory for Bose-Einstein condensates / T. Kita. Spin current in topological cristals / Y. Asano. Antiferromagnetic defects in non-magnetic hidden order of the heavy-electron system URu[symbol]Si[symbol] / H. Amitsuka, K. Tenya and M. Yokoyama. Magnetic-field dependences of thermodynamic quantities in the vortex state of Type-II superconductors / K. Watanabe, T. Kita and M. Arai. Three-magnon-mediated nuclear spin relaxation in quantum ferrimagnets of topological origin / H. Hori and S, Yamamoto. Topological aspects of wave function statistics at t

  17. Insertion Order Virginia Tech Magazine

    E-print Network

    Buehrer, R. Michael

    Insertion Order Virginia Tech Magazine This Insertion Order constitutes an agreement between Virginia Polytechnic Institute and State University (Virginia Tech) and ___________________________ (Client) for advertising space in Virginia Tech Magazine, published by Virginia Tech. Edition(s): Summer 2014 Fall 2014

  18. NCI Mouse Repository - Ordering Information

    Cancer.gov

    STRAIN UNAVAILABLE FOR ORDERING The HB-PLAP(A to G) strain is currently unavailable for ordering. Top of Page | NCI Mouse Repository | Emice Website | Privacy | Disclaimer Available Strains | Newly Accepted Strains | General Info & Help | Frequently

  19. Lepidosauria I. Tuataras (Order Rhynochephalia)

    E-print Network

    Dever, Jennifer A.

    Gambelia sila - endemic Gambelia Family Phrynosomatidae (also considered Iguanids) Fence Lizards, Horned1 Lepidosauria I. Tuataras (Order Rhynochephalia) II. Order Squamata, phylogeny III. Lizard Have acrodont teeth. Draco Moloch horridus Agama III. Lizard Families ~44 native California lizard

  20. Interplay between Frustration and Spin-Orbit Coupling in Vanadates E.D. Mun1, G.-W. Chern2, V. Pardo3, F. Rivadulla3

    E-print Network

    McQuade, D. Tyler

    Pulsed-Field Facility at LANL Instrument/Magnet: 65 T Magnets Citation: Magnetic Field Induced Transition. Theory division, LANL; 3. University of Santiago de Compostela, Spain; 4. U. Tennessee; 5. NHMFL-Pulsed a leading role in determining the magnetic ordering pattern of 3d-based materials. However, in certain

  1. Nematic-isotropic pretransitional behaviour in dimers with odd and even spacer lengths

    Microsoft Academic Search

    Charles Rosenblatt; Anselm C. Griffin; Uma Hari; Geoffrey R. Luckhurst

    1991-01-01

    Magnetic field induced optical birefringence measurements in the isotropic phase are reported for two members of a series of phenyl benzoate dimers: one having an odd number of methylene units in the spacer and one having an even number. The discontinuity at the nematic-isotropic transition, as determined by the difference between the first order phase transition temperature TNI and the

  2. Infrared-active excitations related to Ho3+ ligand-field splitting

    E-print Network

    Sirenko, Andrei

    ; published 6 November 2008 Linearly polarized spectra of far-infrared IR transmission in HoMn2O5 multiferroic and ferroelec- tric orderings has recently motivated extensive studies of rare-earth multiferroic manganites RMn and for possible device applications due to the in- triguing phase diagram and magnetic-field-induced spontane- ous

  3. Cation ordering in complex oxides

    Microsoft Academic Search

    Peter K. Davies

    1999-01-01

    Several recent papers have addressed the fundamental aspects of the stability and kinetics of ordering in complex oxides, and investigated systems where the properties are mediated by the degree of order. Cation ordering reactions have been shown to induce large alterations in the dielectric, ferroelectric, magnetic, and electronic response of many complex oxides. The majority of the cited publications focus

  4. NCI Mouse Repository - Ordering Information

    Cancer.gov

    We have had a number of problems with orders and material transfer agreements (MTAs), so we have prepared instructions to shorten the time for processing orders. The MTA is a legal document. Therefore, please read these instructions completely before placing your order.

  5. Large remnant polarization and magnetic field induced destruction of cycloidal spin structure in Bi{sub 1-x}La{sub x}FeO{sub 3} (0 {<=} x {<=} 0.2)

    SciTech Connect

    Yin, L. H.; Yang, J.; Zhao, B. C.; Liu, Y.; Tan, S. G.; Tang, X. W.; Dai, J. M.; Song, W. H. [Key Laboratory of Materials Physics, Institute of Solid State Physics, Hefei 230031, People's Republic of China (China)] [Key Laboratory of Materials Physics, Institute of Solid State Physics, Hefei 230031, People's Republic of China (China); Sun, Y. P. [Key Laboratory of Materials Physics, Institute of Solid State Physics, Hefei 230031, People's Republic of China (China) [Key Laboratory of Materials Physics, Institute of Solid State Physics, Hefei 230031, People's Republic of China (China); High Magnetic Field Laboratory, Chinese Academy of Sciences, Hefei 230031, People's Republic of China (China)

    2013-06-07

    We prepared a series of Bi{sub 1-x}La{sub x}FeO{sub 3} (0 {<=} x {<=} 0.2) ceramics with a sol-gel method and find that both the magnetization and dielectric constant show an abrupt anomaly near a critical field H{sub c}, which is attributed to the destruction of the cycloidal antiferromagnetic spin structure. The critical field H{sub c} decreases substantially from {approx}20 T for the x = 0 sample [Y. F. Popov et al., JETP Lett. 57, 69 (1993)] to {approx}2.8 T for the x = 0.17 sample and finally to 0 T for the x = 0.2 sample at room temperature (RT). It is also found that H{sub c} increases with decreasing temperature. The variation of H{sub c} with La substitution and temperature can be ascribed to the change in the magnetic anisotropy and isotropic superexchange interaction, respectively. We have also discussed the magnetodielectric effects in these samples in terms of the Ginzburg-Landau theory and the spin-phonon model. Moreover, increasing the doping level of La to 0.15 greatly improves the RT leakage-current and ferroelectric (FE) properties. A RT square-shaped FE hysteresis loop with remnant polarization (2P{sub r}) as high as {approx}64 {mu}C/cm{sup 2} is obtained for the x = 0.15 sample. These results may be important for potential applications in BiFeO{sub 3}-based magnetoelectric devices.

  6. Magnetic-field-induced modifications of the electronic structure of Ni(en)2NO2BF4 : A signature of the Haldane gap in the electronic-excitation intensities

    NASA Astrophysics Data System (ADS)

    Long, V. C.; Chou, Y.-H.; Cross, I. A.; Kozen, A. C.; Montague, J. R.; Schundler, E. C.; Wei, X.; McGill, S. A.; Landry, B. R.; Maxcy-Pearson, K. R.; Turnbull, M. M.; Landee, C. P.

    2007-07-01

    Ni(en)2NO2BF4 (NENB) is isostructural to Ni(en)2NO2ClO4 , the well-known Haldane compound. We have measured the near infrared and visible frequency polarized transmittances of NENB as a function of temperature from 6to300K and in magnetic fields (H) up to 30T . We identify near infrared spin-allowed and spin-forbidden (SF) d-d excitations of the Ni2+ ion as well as a Ni2+ -to- NO2- charge-transfer (CT) transition at 2.5eV , confirmed by vibrational fine structure on the CT band due to the nitrite ion. The spin-allowed d-d bands exhibit temperature dependence consistent with vibronic transitions. The spin-forbidden and electron transfer transitions are noticeably sensitive to magnetic field. Above H?10T , the NENB SF excitation is linearly suppressed by field, whereas the CT transition intensity increases; the onset field agrees with that observed in the high-field magnetization. For comparison, we made the same measurements on a compound having similar near infrared electronic transitions but a different magnetic ground state: the paramagnetic material Ni(en)3(ClO4)2•H2O (NEN3P). The SF bands of NENB are relatively more intense than those of NEN3P, suggesting that a spin exchange mechanism enhances their intensity in NENB, in contrast to activation solely by spin-orbit coupling in NEN3P. The H dependence of the SF band also differs in the two materials; in NEN3P, suppression of the SF intensity commences at H?0T . In general, the contrasting behaviors of field-sensitive excitations in the Haldane and paramagnetic analog compounds reveal a correlation between the electronic structure and magnetic properties.

  7. Default settings of computerized physician order entry system order sets drive ordering habits

    PubMed Central

    Olson, Jordan; Hollenbeak, Christopher; Donaldson, Keri; Abendroth, Thomas; Castellani, William

    2015-01-01

    Background: Computerized physician order entry (CPOE) systems are quickly becoming ubiquitous, and groups of orders (“order sets”) to allow for easy order input are a common feature. This provides a streamlined mechanism to view, modify, and place groups of related orders. This often serves as an electronic equivalent of a specialty requisition. A characteristic, of these order sets is that specific orders can be predetermined to be “preselected” or “defaulted-on” whenever the order set is used while others are “optional” or “defaulted-off” (though there is typically the option is to “deselect” defaulted-on tests in a given situation). While it seems intuitive that the defaults in an order set are often accepted, additional study is required to understand the impact of these “default” settings in an order set on ordering habits. This study set out to quantify the effect of changing the default settings of an order set. Methods: For quality improvement purposes, order sets dealing with transfusions were recently reviewed and modified to improve monitoring of outcome. Initially, the order for posttransfusion hematocrits and platelet count had the default setting changed from “optional” to “preselected.” The default settings for platelet count was later changed back to “optional,” allowing for a natural experiment to study the effect of the default selections of an order set on clinician ordering habits. Results: Posttransfusion hematocrit values were ordered for 8.3% of red cell transfusions when the default order set selection was “off” and for 57.4% of transfusions when the default selection was “preselected” (P < 0.0001). Posttransfusion platelet counts were ordered for 7.0% of platelet transfusions when the initial default order set selection was “optional,” increased to 59.4% when the default was changed to “preselected” (P < 0.0001), and then decreased to 7.5% when the default selection was returned to “optional.” The posttransfusion platelet count rates during the two “optional” periods: 7.0% versus 7.5% – were not statistically different (P = 0.620). Discussion: Default settings in CPOE order sets can significantly influence physician selection of laboratory tests. Careful consideration by all stakeholders, including clinicians and pathologists, should be obtained when establishing default settings in order sets. PMID:25838968

  8. Ordered delinquency: the "effects" of birth order on delinquency.

    PubMed

    Cundiff, Patrick R

    2013-08-01

    Juvenile delinquency has long been associated with birth order in popular culture. While images of the middle child acting out for attention or the rebellious youngest child readily spring to mind, little research has attempted to explain why. Drawing from Adlerian birth order theory and Sulloway's born-to-rebel hypothesis, I examine the relationship between birth order and a variety of delinquent outcomes during adolescence. Following some recent research on birth order and intelligence, I use new methods that allow for the examination of between-individual and within-family differences to better address the potential spurious relationship. My findings suggest that contrary to popular belief, the relationship between birth order and delinquency is spurious. Specifically, I find that birth order effects on delinquency are spurious and largely products of the analytic methods used in previous tests of the relationship. The implications of this finding are discussed. PMID:23719623

  9. Ordered Delinquency: The “Effects” of Birth Order On Delinquency

    PubMed Central

    Cundiff, Patrick R.

    2014-01-01

    Juvenile delinquency has long been associated with birth order in popular culture. While images of the middle child acting out for attention or the rebellious youngest child readily spring to mind, little research has attempted to explain why. Drawing from Adlerian birth order theory and Sulloway's born to rebel hypothesis I examine the relationship between birth order and a variety of delinquent outcomes during adolescence. Following some recent research on birth order and intelligence, I use new methods that allow for the examination of both between-individual and within-family differences to better address the potential spurious relationship. My findings suggest that contrary to popular belief the relationship between birth order and delinquency is spurious. Specifically, I find that birth order effects on delinquency are spurious and largely products of the analytic methods used in previous tests of the relationship. The implications of this finding are discussed. PMID:23719623

  10. Timing of Orders, Order Aggressiveness and the Order Book at the Paris Bourse

    Microsoft Academic Search

    Christophe BISIÈRE; Thierry KAMIONKA

    2000-01-01

    We offer a statistical model of the order flow and estimate it using high frequency data from the Paris Bourse. Our model jointly explains the duration between two consecutive orders and the relative aggressiveness of the orders, depending upon the past ordes and the state of the book. Our results offer evidence of information and liquidity effects, as put forward

  11. Surface melting of electronic order.

    SciTech Connect

    Wilkins, S. B.; Liu, X.; Wakabayashi, Y.; Kim, J.-W.; Ryan, P. J.; Mitchell, J. F.; Hill, J. P. (Materials Science Division); ( XSD); (BNL); (Osaka Univ.)

    2011-01-01

    We report temperature-dependent surface x-ray scattering studies of the orbital ordered surface in La{sub 0.5}Sr{sub 1.5}MnO{sub 4}. We find that as the bulk ordering temperature is approached from below the thickness of the interface between the electronically ordered and electronically disordered regions at the surface grows, though the bulk correlation length remains unchanged. Close to the transition, the surface is so rough that there is no well-defined electronic surface, despite the presence of bulk electronic order. That is, the electronic ordering at the surface has melted. Above the bulk transition, long-range ordering in the bulk is destroyed but finite-sized isotropic fluctuations persist, with a correlation length roughly equal to that of the low-temperature in-plane surface correlation length.

  12. Adiabatic Preparation of Topological Order

    E-print Network

    Alioscia Hamma; Daniel A. Lidar

    2007-10-13

    Topological order characterizes those phases of matter that defy a description in terms of symmetry and cannot be distinguished in terms local order parameters. This type of order plays a key role in the theory of the fractional quantum Hall effect, as well as in topological quantum information processing. Here we show that a system of n spins forming a lattice on a Riemann surface can undergo a second order quantum phase transition between a spin-polarized phase and a string-net condensed phase. This is an example of a phase transition between magnetic and topological order. We furthermore show how to prepare the topologically ordered phase through adiabatic evolution in a time that is upper bounded by O(\\sqrt{n}). This provides a physically plausible method for constructing a topological quantum memory. We discuss applications to topological and adiabatic quantum computing.

  13. Probabilistic Higher Order Differential Attack and Higher Order Bent Functions

    Microsoft Academic Search

    Tetsu Iwata; Kaoru Kurosawa

    1999-01-01

    . We first show that a Feistel type block cipher is broken ifthe round function is approximated by a low degree vectorial Booleanfunction. The proposed attack is a generalization of the higher orderdifferential attack to a probabilistic one. We next introduce a notion ofhigher order bent functions in order to prevent our attack. We then showtheir explicit constructions.1

  14. Counterbalancing for Serial Order Carryover Effects in Experimental Condition Orders

    ERIC Educational Resources Information Center

    Brooks, Joseph L.

    2012-01-01

    Reactions of neural, psychological, and social systems are rarely, if ever, independent of previous inputs and states. The potential for serial order carryover effects from one condition to the next in a sequence of experimental trials makes counterbalancing of condition order an essential part of experimental design. Here, a method is proposed…

  15. Ordering variable for parton showers

    NASA Astrophysics Data System (ADS)

    Nagy, Zoltán; Soper, Davison E.

    2014-06-01

    The parton splittings in a parton shower are ordered according to an ordering variable, for example the transverse momentum of the daughter partons relative to the direction of the mother, the virtuality of the splitting, or the angle between the daughter partons. We analyze the choice of the ordering variable and conclude that one particular choice has the advantage of factoring softer splittings from harder splittings graph by graph in a physical gauge.

  16. 7 CFR 1214.12 - Order.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE CHRISTMAS TREE PROMOTION, RESEARCH, AND INFORMATION ORDER Christmas Tree Promotion, Research, and Information Order Definitions § 1214.12 Order....

  17. 7 CFR 1214.12 - Order.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE CHRISTMAS TREE PROMOTION, RESEARCH, AND INFORMATION ORDER Christmas Tree Promotion, Research, and Information Order Definitions § 1214.12 Order....

  18. 7 CFR 1214.12 - Order.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE CHRISTMAS TREE PROMOTION, RESEARCH, AND INFORMATION ORDER Christmas Tree Promotion, Research, and Information Order Definitions § 1214.12 Order....

  19. Birth Order: Reconciling Conflicting Effects.

    ERIC Educational Resources Information Center

    Zajonc, Robert B.; Mullally, Patricia R.

    1997-01-01

    Introduces the confluence model as a theory specifying the process by which the intellectual environment modifies intellectual development. Using this model, explores the contradiction between prediction of secular trends in test scores by trends in aggregate birth order and the lack of prediction of individual test scores by birth order using…

  20. Market Depth and Order Size

    Microsoft Academic Search

    Alexander Kempf; Olaf Korn

    1997-01-01

    In this paper we empirically analyze the permanent price impact of trades by investigating the relation between unexpected net order flow and price changes. We use intraday data on German index futures. Our analysis based on a neural network model suggests that the assumption of a linear impact of orders on prices (which is often used in theoretical papers) is

  1. Commonalities in the order book

    Microsoft Academic Search

    Helena Beltran-Lopez; Pierre Giot; Joachim Grammig

    2006-01-01

    This paper uses data from one of the most important European stock markets and shows that, in line with predictions from theoretical market microstructure, a small number of latent factors captures most of the variation in stock specific order books. We show that these order book commonalities are much stronger than liquidity commonality across stocks. The result that bid and

  2. Children's Order 10 Years on

    ERIC Educational Resources Information Center

    Kerr, Linda

    2006-01-01

    Ten years ago I wrote an article on the Children's Order, which was coming into force in Northern Ireland in October 1996. I examined the principles behind the Children's Order and considered how these principles interacted with the practice of family mediation (at that stage I was Coordinator of the Family Mediation service). Since that date…

  3. Altera Corporation 1 Ordering Information

    E-print Network

    Berns, Hans-Gerd

    , and the most current on-line and printed documentation. Table 1 explains the ordering codes for the Altera Customer Marketing at (408) 544-7104. Figure 1. Device Package Ordering Information for APEX 20K, APEX 20KE Subscription Program. For information on specific products, contact Altera Customer Marketing at (408) 544

  4. Quantifying Order in Semiconducting Polymers

    NASA Astrophysics Data System (ADS)

    Snyder, Chad

    2015-03-01

    Semiconducting polymers form the basis for the burgeoning flexible electronics industry. However, quantifying their order can be challenging due to the nanophase separation induced by the side chains which are used to impart solubility, their propensity to form mesophases, and their often high levels of paracrystalline disorder. Recent successes in our laboratory in understanding these materials and quantifying their order will be presented.

  5. Dual-order Raman pump

    Microsoft Academic Search

    J.-C. Bouteiller; K. Brar; J. Bromage; S. Radic; C. Headley

    2003-01-01

    This letter presents the design of a dual-order Raman fiber laser to be used as a pump for distributed Raman amplification. In particular, noise figure, gain ripple, and tunability are measured and analyzed in comparison to first-order Raman amplification. The tradeoff between noise figure improvement and increased nonlinear penalty is also discussed.

  6. Two-dimensional nuclear magnetic resonance of quadrupolar systems

    E-print Network

    Wang, Shuanhu

    2010-01-01

    spectwm at 11.7T. of anorthite. Isotropic chen]ica] shiftsof at least 9S(Z. The anorthite ~v{,l. (. Ilil(l(. ill S1~~i~~ (’~~ihf.i~n 3.1 Sd, anorthite, ‘71? 1>(Figure 3.lSa,

  7. The price impact of order book events: market orders, limit orders and cancellations

    Microsoft Academic Search

    Zoltan Eisler; Jean-Philippe Bouchaud; Julien Kockelkoren

    2009-01-01

    While the long-ranged correlation of market orders and their impact on prices has been relatively well studied in the literature, the corresponding studies of limit orders and cancellations are scarce. We provide here an empirical study of the cross-correlation between all these different events, and their respective impact on future price changes. We define and extract from the data the

  8. Multiple order common path spectrometer

    NASA Technical Reports Server (NTRS)

    Newbury, Amy B. (Inventor)

    2010-01-01

    The present invention relates to a dispersive spectrometer. The spectrometer allows detection of multiple orders of light on a single focal plane array by splitting the orders spatially using a dichroic assembly. A conventional dispersion mechanism such as a defraction grating disperses the light spectrally. As a result, multiple wavelength orders can be imaged on a single focal plane array of limited spectral extent, doubling (or more) the number of spectral channels as compared to a conventional spectrometer. In addition, this is achieved in a common path device.

  9. Complex higher order derivative theories

    SciTech Connect

    Margalli, Carlos A.; Vergara, J. David [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Apartado Postal 70-543, Mexico 04510 DF (Mexico)

    2012-08-24

    In this work is considered a complex scalar field theory with higher order derivative terms and interactions. A procedure is developed to quantize consistently this system avoiding the presence of negative norm states. In order to achieve this goal the original real scalar high order field theory is extended to a complex space attaching a complex total derivative to the theory. Next, by imposing reality conditions the complex theory is mapped to a pair of interacting real scalar field theories without the presence of higher derivative terms.

  10. Boundary degeneracy of topological order

    E-print Network

    Wen, Xiao-Gang

    We introduce the concept of boundary degeneracy, as the ground state degeneracy of topologically ordered states on a compact orientable spatial manifold with gapped boundaries. We emphasize that the boundary degeneracy ...

  11. Reduced order adaptive controller studies

    NASA Technical Reports Server (NTRS)

    Johnson, C. R., Jr.; Balas, M. J.

    1980-01-01

    The use of a reduced-order adaptive controller, can arise from a desire to reduce control complexity with a commensurate reduction in controller sensitivity or from necessity in an attempt to use a finite dimensional controller on an infinite dimensional system. An interest in developing adaptive controllers for flexible structures by application of existing lumped-parameter system (LPS) adaptive controller strategies to truncated expansion descriptions of the distributed parameter system (DPS) behavior of flexible structures has led to two qualitative descriptions of the misbehavior of reduced-order adaptive controllers. A summary is provided of these interpretations of the additional difficulties facing reduced-order adaptive controllers, which are bypassed by exact-order adaptive controllers. A test problem, which initializes attempts to quantify the qualitative insights, is also formulated.

  12. Author Order and Research Quality

    E-print Network

    Kissan, Joseph; Laband, David N.; Patil, Vivek

    2005-01-01

    We observe a great deal of heterogeneity in the manner in which author orderings are assigned both across and within academic markets. To better understand this phenomenon, we develop and analyze a stochastic model of ...

  13. Higher-order Fibonacci numbers

    Microsoft Academic Search

    Milan Randi?; Daniel A. Morales; Oswaldo Araujo

    1996-01-01

    We consider a generalization of Fibonacci numbers that was motivated by the relationship of the HosoyaZ topological index to the Fibonacci numbers. In the case of the linear chain structures the new higher order Fibonacci numbershFn are directly related to the higher order Hosoya-typeZ numbers. We investigate the limitsFn\\/Fn-1 and the corresponding equations, the roots of which allow one to

  14. John F. Kennedy Executive Orders

    NSDL National Science Digital Library

    Kennedy, John F. (John Fitzgerald), 1917-1963.

    The 214 Executive Orders signed by the 35th President have been scanned and converted to HTML by Maria E. Schieda of the University of Michigan School of Information. These include the orders to establish the Peace Corps (E.O. 10924), to establish the President's Committee on Equal Employment (E.O. 10925), and emergency instructions to government agencies during the Cuban Missile Crisis (E.O. 11051, 11058, 11087-11095). The collection is indexed by date, keyword, number, and title.

  15. Higher order parametric x rays

    NASA Astrophysics Data System (ADS)

    Osborne, Michael J.

    1991-12-01

    Parametric x-radiation (PXR) may be described as the Bragg scattering of virtual photons to produce real x-rays which satisfy the Bragg condition dsin theta = n(lambda), where theta is the angle between the electron beam direction and a crystal axis. Enhanced higher order parametric x-radiation from the (002) plane of a mosaic graphite crystal has been observed. Production of PXR of the order n = 2 exceed that from the first order, and x-rays of order up to n = 6 are readily seen. The production of higher order x-radiation is obtained by using a thick crystal where the formation and attenuation lengths are exploited to enhance higher energy x-ray formation relative to the lower energy first order x-radiation. Photons of energy 5 to 30 KeV have been measured. The experiment was conducted with a 90 MeV electron beam from the Naval Postgraduate School electron linear accelerator. A three axis target position program, Easy-Mover, was developed to allow for precision orientation of the crystal axis with respect to the electron beam.

  16. Total-Order Planning with Partially Ordered Subtasks

    Microsoft Academic Search

    Dana S. Nau; Héctor Muñoz-avila; Yue Cao; Amnon Lotem; Steven Mitchell

    2001-01-01

    One of the more controversial recent planning algorithms is the SHOP algorithm, an HTN planning algorithm that plans for tasks in the same order that they are to be executed. SHOP can use domain- dependent knowledge to generate plans very quickly, but it can be difficult to write good knowledge bases for SHOP. Our hypothesis is that this difficulty is

  17. Order effects in dynamic semantics.

    PubMed

    Graben, Peter Beim

    2014-01-01

    In their target article, Wang and Busemeyer (2013) discuss question order effects in terms of incompatible projectors on a Hilbert space. In a similar vein, Blutner recently presented an orthoalgebraic query language essentially relying on dynamic update semantics. Here, I shall comment on some interesting analogies between the different variants of dynamic semantics and generalized quantum theory to illustrate other kinds of order effects in human cognition, such as belief revision, the resolution of anaphors, and default reasoning that result from the crucial non-commutativity of mental operations upon the belief state of a cognitive agent. PMID:24259268

  18. Risk attitudes and birth order.

    PubMed

    Krause, Philipp; Heindl, Johannes; Jung, Andreas; Langguth, Berthold; Hajak, Göran; Sand, Philipp G

    2014-07-01

    Risk attitudes play important roles in health behavior and everyday decision making. It is unclear, however, whether these attitudes can be predicted from birth order. We investigated 200 mostly male volunteers from two distinct settings. After correcting for multiple comparisons, for the number of siblings and for confounding by gender, ordinal position predicted perception of health-related risks among participants in extreme sports (p < .01). However, the direction of the effect contradicted Adlerian theory. Except for alcohol consumption, these findings extended to self-reported risk behavior. Together, the data call for a cautious stand on the impact of birth order on risk attitudes. PMID:23520357

  19. Order Symmetry of Weak Measurements

    E-print Network

    Lars M. Johansen; Pier A. Mello

    2009-07-30

    Weak values are usually associated with weak measurements of an observable on a pre- and post-selected ensemble. We show that more generally, weak values are proportional to the correlation between two pointers in a successive measurement. We show that this generalized concept of weak measurements displays a symmetry under reversal of measurement order. We show that the conditions for order symmetry are the same as in classical mechanics. We also find that the imaginary part of the weak value has a counterpart in classical mechanics. This scheme suggests new experimental possibilities.

  20. Moral Order and the Humanities.

    ERIC Educational Resources Information Center

    Howard, Thomas

    1980-01-01

    Argues that a society without reverence for myths and history inevitably falls prone to chaos and evil, pointing to abortion, Andy Warhol's celebrity, and Woodstock as evidence of this disintegration of society. Proposes that humanities education expose students to human experience based on some awesome and fixed moral order. (AYC)

  1. Birth order and academic primogeniture

    Microsoft Academic Search

    William D. Altus

    1965-01-01

    Data were obtained on the birth order of students entering in 1960, 1961, 1962, and 1963, at the University of California, Santa Barbara. Previous studies had shown the 1st born to be overrepresented among college students. The present study confirms this trend: Over 60% of all entering students are 1st born if the only child is included as a 1st

  2. Order computations in generic groups

    E-print Network

    Sutherland, Andrew V

    2007-01-01

    We consider the problem of computing the order of an element in a generic group. The two standard algorithms, Pollard's rho method and Shanks' baby-steps giant-steps technique, both use [theta](N^1/2) group operations to ...

  3. Suffix Ordering and Morphological Processing

    ERIC Educational Resources Information Center

    Plag, Ingo; Baayen, Harald

    2009-01-01

    There is a long-standing debate about the principles constraining the combinatorial properties of suffixes. Hay 2002 and Hay & Plag 2004 proposed a model in which suffixes can be ordered along a hierarchy of processing complexity. We show that this model generalizes to a larger set of suffixes, and we provide independent evidence supporting the…

  4. 7 CFR 917.100 - Order.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE FRESH PEARS AND PEACHES GROWN IN CALIFORNIA Rules and Regulations Definitions § 917.100 Order. Order means Marketing Order No....

  5. 7 CFR 917.100 - Order.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; FRUITS, VEGETABLES, NUTS), DEPARTMENT OF AGRICULTURE FRESH PEARS AND PEACHES GROWN IN CALIFORNIA Rules and Regulations Definitions § 917.100 Order. Order means Marketing Order No....

  6. 7 CFR 917.100 - Order.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...MARKETING SERVICE (Marketing Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE FRESH PEARS AND PEACHES GROWN IN CALIFORNIA Rules and Regulations Definitions § 917.100 Order. Order means Marketing Order No....

  7. Weighted order statistic classifiers with large rank-order margin.

    SciTech Connect

    Porter, R. B. (Reid B.); Hush, D. R. (Donald R.); Theiler, J. P. (James P.); Gokhale, M. (Maya)

    2003-01-01

    We describe how Stack Filters and Weighted Order Statistic function classes can be used for classification problems. This leads to a new design criteria for linear classifiers when inputs are binary-valued and weights are positive . We present a rank-based measure of margin that can be directly optimized as a standard linear program and investigate its effect on generalization error with experiment. Our approach can robustly combine large numbers of base hypothesis and easily implement known priors through regularization.

  8. Angle Orders, Regular n-gon Orders Crossing Number of a Partial Order

    E-print Network

    Urrutia, Jorge

    orders of dimension 3 are representable using equliateral triangles with the same orientation the x-axis, then for each interval Ij of F build a circle Cj such that Ij is a diameter of Cj, however, does not solve their problem of deciding whether there are dimension 5 posets which are not angle

  9. Perturbative gadgets at arbitrary orders

    NASA Astrophysics Data System (ADS)

    Jordan, Stephen P.; Farhi, Edward

    2008-06-01

    Adiabatic quantum algorithms are often most easily formulated using many-body interactions. However, experimentally available interactions are generally two-body. In 2004, Kempe, Kitaev, and Regev introduced perturbative gadgets, by which arbitrary three-body effective interactions can be obtained using Hamiltonians consisting only of two-body interactions. These three-body effective interactions arise from the third order in perturbation theory. Since their introduction, perturbative gadgets have become a standard tool in the theory of quantum computation. Here we construct generalized gadgets so that one can directly obtain arbitrary k -body effective interactions from two-body Hamiltonians. These effective interactions arise from the k th order in perturbation theory.

  10. Perturbative Gadgets at Arbitrary Orders

    E-print Network

    Stephen P. Jordan; Edward Farhi

    2012-01-31

    Adiabatic quantum algorithms are often most easily formulated using many-body interactions. However, experimentally available interactions are generally two-body. In 2004, Kempe, Kitaev, and Regev introduced perturbative gadgets, by which arbitrary three-body effective interactions can be obtained using Hamiltonians consisting only of two-body interactions. These three-body effective interactions arise from the third order in perturbation theory. Since their introduction, perturbative gadgets have become a standard tool in the theory of quantum computation. Here we construct generalized gadgets so that one can directly obtain arbitrary k-body effective interactions from two-body Hamiltonians. These effective interactions arise from the kth order in perturbation theory.

  11. Multiple sclerosis and birth order.

    PubMed Central

    James, W H

    1984-01-01

    Studies on the birth order of patients with multiple sclerosis have yielded contradictory conclusions. Most of the sets of data, however, have been tested by biased tests. Data that have been submitted to unbiased tests seem to suggest that cases are more likely to occur in early birth ranks. This should be tested on further samples and some comments are offered on how this should be done. PMID:6707558

  12. The social order of markets

    Microsoft Academic Search

    Jens Beckert

    2009-01-01

    In this article I develop a proposal for the theoretical vantage point of the sociology of markets, focusing on the problem\\u000a of the social order of markets. The initial premise is that markets are highly demanding arenas of social interaction, which\\u000a can only operate if three inevitable coordination problems are resolved. I define these coordination problems as the value problem,

  13. Perturbative gadgets at arbitrary orders

    Microsoft Academic Search

    Stephen P. Jordan; Edward Farhi

    2008-01-01

    Adiabatic quantum algorithms are often most easily formulated using many-body interactions. However, experimentally available interactions are generally two-body. In 2004, Kempe, Kitaev, and Regev introduced perturbative gadgets, by which arbitrary three-body effective interactions can be obtained using Hamiltonians consisting only of two-body interactions. These three-body effective interactions arise from the third order in perturbation theory. Since their introduction, perturbative gadgets

  14. JOURNAL DE PHYSIQUE Colloque C5, supplment au n 5, Tome 40, Mai 1979, page C5-141 Magnetic excitations in HoZn and ErCu compounds

    E-print Network

    Paris-Sud XI, Université de

    of the magnetoelastic or quadrupolar couplings. 1. Introduction. -- The aim of present work is to study the propagation indirect couplings, are the interactions isotropic or not, may higher order exchange and magnetoelastic = -- 3 d/J(J + 1), 3) second order magnetoelastic and quadrupolar couplings defined by two parameters B2

  15. 8.EE Orders of Magnitude

    NSDL National Science Digital Library

    This is a task from the Illustrative Mathematics website that is one part of a complete illustration of the standard to which it is aligned. Each task has at least one solution and some commentary that addresses important asects of the task and its potential use. Here are the first few lines of the commentary for this task: It is said that the average person blinks about 1000 times an hour. This is an order-of-magnitude estimate, that is, it is an estimate given as a power...

  16. REACTION PHYSICAL PLANT MODULE WORK ORDER ------------------------------------------------2

    E-print Network

    Zimmerman, Steven C.

    1 REACTION PHYSICAL PLANT MODULE USER MENU WORK ORDER;2 ADD WORK ORDER: 1. Logon to Reaction 2. Go to Physical Plant Add Work Order. Or Click Here 3. Enter SEARCH WORK ORDER: 1. Logon to Reaction 2. Go to Physical Plant Search Work Order. Or Click Here 3

  17. A concept of generalized order statistics

    Microsoft Academic Search

    Udo Kamps

    1995-01-01

    A form of the joint distribution of n ordered random variables is presented that enables a unified approach to a variety of models of ordered random variables, e.g. order statistics and record values. Several other models are shown. In particular, sequential order statistics are introduced as a modification of order statistics which is naturally suggested by a statistical application in

  18. The Fitness of Genomic Order

    NASA Astrophysics Data System (ADS)

    Zhang, Qiucen; Vyawahare, Saurabh; Austin, Robert

    2012-02-01

    Most bacteria have a single circular chromosome that can range in size from 160,000 to 12,200,000 base pairs. Considering the typical gene density, i.e. 1 gene per 1,000 base pairs, both the number of genes and the ways to arrange are huge. Intuitively, the arrangement of genes on the circle is not important if all of them can be replicated. However, there is typically one origin of replication, and when bacteria is attacked by genotoxic stress during replication, the whole replication process can not be finished. As a result, which gene is replicated first, which is second, ..., becomes very important. Experimentally, we found a broad increase of DNA copy number near the origin of replication (OriC) of bacteria E.coli (˜3200 genes) under genotoxic stress. Since the genes near OriC are mostly efflux pump genes, we propose that there is fitness advantage for those rapid stress response genes got replicated first, because they can facilitate the replication of the rest of genome. Similar to bacterial evolution to present genomic order, in the somatic evolution of cancer, genomic shuffling was also frequently observed, especially under genotoxic chemotherapy. Such re-arrangement of genome can be viewed as a journey to optimal point in the rugged fitness landscape of genomic order.

  19. Biocatalytic induction of supramolecular order

    NASA Astrophysics Data System (ADS)

    Hirst, Andrew R.; Roy, Sangita; Arora, Meenakshi; Das, Apurba K.; Hodson, Nigel; Murray, Paul; Marshall, Stephen; Javid, Nadeem; Sefcik, Jan; Boekhoven, Job; van Esch, Jan H.; Santabarbara, Stefano; Hunt, Neil T.; Ulijn, Rein V.

    2010-12-01

    Supramolecular gels, which demonstrate tunable functionalities, have attracted much interest in a range of areas, including healthcare, environmental protection and energy-related technologies. Preparing these materials in a reliable manner is challenging, with an increased level of kinetic defects observed at higher self-assembly rates. Here, by combining biocatalysis and molecular self-assembly, we have shown the ability to more quickly access higher-ordered structures. By simply increasing enzyme concentration, supramolecular order expressed at molecular, nano- and micro-levels is dramatically enhanced, and, importantly, the gelator concentrations remain identical. Amphiphile molecules were prepared by attaching an aromatic moiety to a dipeptide backbone capped with a methyl ester. Their self-assembly was induced by an enzyme that hydrolysed the ester. Different enzyme concentrations altered the catalytic activity and size of the enzyme clusters, affecting their mobility. This allowed structurally diverse materials that represent local minima in the free energy landscape to be accessed based on a single gelator structure.

  20. 7 CFR 1212.15 - Order.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...COMMODITIES), DEPARTMENT OF AGRICULTURE HONEY PACKERS AND IMPORTERS RESEARCH, PROMOTION...EDUCATION AND INDUSTRY INFORMATION ORDER Honey Packers and Importers Research, Promotion...1212.15 Order. “Order” means the Honey Packers and Importers Research,...

  1. 7 CFR 1212.15 - Order.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...COMMODITIES), DEPARTMENT OF AGRICULTURE HONEY PACKERS AND IMPORTERS RESEARCH, PROMOTION...EDUCATION AND INDUSTRY INFORMATION ORDER Honey Packers and Importers Research, Promotion...1212.15 Order. “Order” means the Honey Packers and Importers Research,...

  2. 7 CFR 1212.15 - Order.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...COMMODITIES), DEPARTMENT OF AGRICULTURE HONEY PACKERS AND IMPORTERS RESEARCH, PROMOTION...EDUCATION AND INDUSTRY INFORMATION ORDER Honey Packers and Importers Research, Promotion...1212.15 Order. “Order” means the Honey Packers and Importers Research,...

  3. 7 CFR 1212.15 - Order.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...COMMODITIES), DEPARTMENT OF AGRICULTURE HONEY PACKERS AND IMPORTERS RESEARCH, PROMOTION...EDUCATION AND INDUSTRY INFORMATION ORDER Honey Packers and Importers Research, Promotion...1212.15 Order. “Order” means the Honey Packers and Importers Research,...

  4. 7 CFR 1212.15 - Order.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...COMMODITIES), DEPARTMENT OF AGRICULTURE HONEY PACKERS AND IMPORTERS RESEARCH, PROMOTION...EDUCATION AND INDUSTRY INFORMATION ORDER Honey Packers and Importers Research, Promotion...1212.15 Order. “Order” means the Honey Packers and Importers Research,...

  5. 49 CFR 109.17 - Emergency Orders.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 2 2013-10-01 2013-10-01 false Emergency Orders. 109.17 Section 109.17 Transportation...PROCEDURAL REGULATIONS FOR OPENING OF PACKAGES, EMERGENCY ORDERS, AND EMERGENCY RECALLS Emergency Orders § 109.17...

  6. 49 CFR 109.17 - Emergency Orders.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 2 2012-10-01 2012-10-01 false Emergency Orders. 109.17 Section 109.17 Transportation...PROCEDURAL REGULATIONS FOR OPENING OF PACKAGES, EMERGENCY ORDERS, AND EMERGENCY RECALLS Emergency Orders § 109.17...

  7. 49 CFR 109.17 - Emergency Orders.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 2 2011-10-01 2011-10-01 false Emergency Orders. 109.17 Section 109.17 Transportation...PROCEDURAL REGULATIONS FOR OPENING OF PACKAGES, EMERGENCY ORDERS, AND EMERGENCY RECALLS Emergency Orders § 109.17...

  8. 6 CFR 27.300 - Orders.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...Section 27.300 Domestic Security DEPARTMENT OF HOMELAND SECURITY, OFFICE OF THE SECRETARY CHEMICAL FACILITY ANTI-TERRORISM STANDARDS Orders and Adjudications § 27.300 Orders. (a) Orders Generally. When the Assistant...

  9. Statistical problem Ordered processes: definition, properties, examples

    E-print Network

    Golubev, Yuri

    Statistical problem Ordered processes: definition, properties, examples Linear models and spectral Oracle inequalities #12;Statistical problem Ordered processes: definition, properties, examples Linear Statistical problem 2 Ordered processes: definition, properties, examples 3 Linear models and spectral

  10. 7 CFR 1205.16 - Order.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE COTTON RESEARCH AND PROMOTION Procedures for Conduct of Sign-up Period Definitions § 1205.16 Order. The term Order means the Cotton Research and Promotion...

  11. 7 CFR 1205.16 - Order.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE COTTON RESEARCH AND PROMOTION Procedures for Conduct of Sign-up Period Definitions § 1205.16 Order. The term Order means the Cotton Research and Promotion...

  12. 7 CFR 1205.16 - Order.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE COTTON RESEARCH AND PROMOTION Procedures for Conduct of Sign-up Period Definitions § 1205.16 Order. The term Order means the Cotton Research and Promotion...

  13. 7 CFR 1205.16 - Order.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE COTTON RESEARCH AND PROMOTION Procedures for Conduct of Sign-up Period Definitions § 1205.16 Order. The term Order means the Cotton Research and Promotion...

  14. 7 CFR 1205.16 - Order.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE COTTON RESEARCH AND PROMOTION Procedures for Conduct of Sign-up Period Definitions § 1205.16 Order. The term Order means the Cotton Research and Promotion...

  15. Ordered structures and jet noise

    NASA Technical Reports Server (NTRS)

    Petersen, R. A.; Kaplan, R. E.; Laufer, J.

    1974-01-01

    A series of measurements of near field pressures and turbulent velocity fluctuations were made in a jet having a Reynolds number of about 50,000 in order to investigate more quantitatively the character and behavior of the large scale structures, and to ascertain their importance to the jet noise problem. It was found that the process of interaction between vortices can be inhibited by artificially exciting the shear layers with periodic disturbances of certain frequency. The turbulent fluctuation amplitudes measured at four diameters downstream decreased considerably. Finally, it was observed that the passage frequency of the structures decreased with x in a similar manner as the frequency corresponding to the maximum intensity radiation emanating from the same value of x.

  16. Recent advances in ordered intermetallics

    SciTech Connect

    Liu, C.T.

    1992-12-31

    This paper briefly summarizes recent advances in intermetallic research and development. Ordered intermetallics based on aluminides and silicides possess attractive properties for structural applications at elevated temperatures in hostile environments; however, brittle fracture and poor fracture resistance limit their use as engineering materials in many cases. In recent years, considerable efforts have been devoted to the study of the brittle fracture behavior of intermetallic alloys; as a result, both intrinsic and extrinsic factors governing brittle fracture have been identified. Recent advances in first-principles calculations and atomistic simulations further help us in understanding atomic bonding, dislocation configuration, and alloying effects in intermetallics. The basic understanding has led to the development of nickel, iron, and titanium aluminide alloys with improved mechanical and metallurgical properties for structural use. Industrial interest in ductile intermetallic alloys is high, and several examples of industrial involvement are mentioned.

  17. Ferromagnetic ordering in superatomic solids.

    PubMed

    Lee, Chul-Ho; Liu, Lian; Bejger, Christopher; Turkiewicz, Ari; Goko, Tatsuo; Arguello, Carlos J; Frandsen, Benjamin A; Cheung, Sky C; Medina, Teresa; Munsie, Timothy J S; D'Ortenzio, Robert; Luke, Graeme M; Besara, Tiglet; Lalancette, Roger A; Siegrist, Theo; Stephens, Peter W; Crowther, Andrew C; Brus, Louis E; Matsuo, Yutaka; Nakamura, Eiichi; Uemura, Yasutomo J; Kim, Philip; Nuckolls, Colin; Steigerwald, Michael L; Roy, Xavier

    2014-12-01

    In order to realize significant benefits from the assembly of solid-state materials from molecular cluster superatomic building blocks, several criteria must be met. Reproducible syntheses must reliably produce macroscopic amounts of pure material; the cluster-assembled solids must show properties that are more than simply averages of those of the constituent subunits; and rational changes to the chemical structures of the subunits must result in predictable changes in the collective properties of the solid. In this report we show that we can meet these requirements. Using a combination of magnetometry and muon spin relaxation measurements, we demonstrate that crystallographically defined superatomic solids assembled from molecular nickel telluride clusters and fullerenes undergo a ferromagnetic phase transition at low temperatures. Moreover, we show that when we modify the constituent superatoms, the cooperative magnetic properties change in predictable ways. PMID:25379957

  18. Confetti Ordering by Polymer Brushes

    E-print Network

    Galen T. Pickett

    2015-05-23

    I consider the ordering of dilute platelet additives when incorporated into an end-grafted polymer brush. The competition between wetting interactions and the anisotropic stress environment of the interior of the brush causes these platelet additives to either remain suspended at the outer edge of the brush laying flat against the brush surface (as bits of confetti at rest on the ground), or to invade the interior of the brush in which case the platelets stand end-on and in some cases protrude above the outer edge of the brush. The orientation of the additives is controlled by the ratio of the diameter of the additive to the thickness of the bare brush, as well as the ratio of solvent-monomer and solvent-platelet interactions.

  19. Deriving Laws from Ordering Relations

    NASA Technical Reports Server (NTRS)

    Knuth, Kevin H.

    2003-01-01

    It took much effort in the early days of non-Euclidean geometry to break away from the mindset that all spaces are flat and that two distinct parallel lines do not cross. Up to that point, all that was known was Euclidean geometry, and it was difficult to imagine anything else. We have suffered a similar handicap brought on by the enormous relevance of Boolean algebra to the problems of our age-logic and set theory. Previously, I demonstrated that the algebra of questions is not Boolean, but rather is described by the free distributive algebra. To get to this stage took much effort, as many obstacles-most self-placed-had to be overcome. As Boolean algebras were all I had ever known, it was almost impossible for me to imagine working with an algebra where elements do not have complements. With this realization, it became very clear that the sum and product rules of probability theory at the most basic level had absolutely nothing to do with the Boolean algebra of logical statements. Instead, a measure of degree of inclusion can be invented for many different partially ordered sets, and the sum and product rules fall out of the associativity and distributivity of the algebra. To reinforce this very important idea, this paper will go over how these constructions are made, while focusing on the underlying assumptions. I will derive the sum and product rules for a distributive lattice in general and demonstrate how this leads to probability theory on the Boolean lattice and is related to the calculus of quantum mechanical amplitudes on the partially ordered set of experimental setups. I will also discuss the rules that can be derived from modular lattices and their relevance to the cross-ratio of projective geometry.

  20. Higher order turbulence closure models

    NASA Technical Reports Server (NTRS)

    Amano, Ryoichi S.; Chai, John C.; Chen, Jau-Der

    1988-01-01

    Theoretical models are developed and numerical studies conducted on various types of flows including both elliptic and parabolic. The purpose of this study is to find better higher order closure models for the computations of complex flows. This report summarizes three new achievements: (1) completion of the Reynolds-stress closure by developing a new pressure-strain correlation; (2) development of a parabolic code to compute jets and wakes; and, (3) application to a flow through a 180 deg turnaround duct by adopting a boundary fitted coordinate system. In the above mentioned models near-wall models are developed for pressure-strain correlation and third-moment, and incorporated into the transport equations. This addition improved the results considerably and is recommended for future computations. A new parabolic code to solve shear flows without coordinate tranformations is developed and incorporated in this study. This code uses the structure of the finite volume method to solve the governing equations implicitly. The code was validated with the experimental results available in the literature.

  1. Fourth order spatial derivative gravity

    E-print Network

    F. S. Bemfica; M. Gomes

    2011-10-12

    In this work we study a modified theory of gravity that contains up to fourth order spatial derivatives as a model for the Horava-Lifshitz gravity. The propagator is evaluated and, as a result, it is obtained one extra pole corresponding to a spin two nonrelativistic massless particle, an extra term which jeopardizes renormalizability, besides the unexpected general relativity unmodified propagator. Then, unitarity is proved at the tree-level, where the general relativity pole has shown to have no dynamics, remaining only the two degrees of freedom of the new pole. Next, the nonrelativistic effective potential is determined from a scattering process of two identical massive gravitationally interacting bosons. In this limit, Newton's potential is obtained, together with a Darwin-like term that comes from the extra non-pole term in the propagator. Regarding renormalizability, this extra term may be harmful, by power counting, but it can be eliminated by adjusting the free parameters of the model. This adjustment is in accord with the detailed balance condition suggested in the literature and shows that the way in which extra spatial derivative terms are added is of fundamental importance.

  2. Girls, pecking order and smoking.

    PubMed

    Michell, L; Amos, A

    1997-06-01

    Against a background of growing concern about the failure to reduce cigarette smoking amongst young people, particularly girls, this paper attempts to unravel the complex interrelationships between smoking, peer group structure and gender. We were particularly intrigued to explore a recent hypothesis in the literature that suggests that girls who smoke, far from lacking self-esteem, are more self-confident and socially skilled than their non-smoking peers. Sociometric and qualitative analyses revealed that smoking behaviour was indeed shaped by gender, and that the psychosocial processes involved in smoking uptake may be different for boys and than for girls. Peer group structure, consistently described by young people as hierarchical, was closely related to smoking behaviour. Girls at the top of the social pecking order who projected an image of high self-esteem were identified as most likely to smoke, while only a small minority of girls fitted the stereotype of the young female smoker who has poor social skills and low self-esteem. Boys of high social status were less vulnerable, since sport and a desire to be fit to some extent protected them. Our findings raise fundamental questions about the meaning of self-esteem in relation to smoking uptake, arguing instead for an exploration of the term "self-worth". They suggest the need for health education programmes which are sensitive both to gender and to peer group structures. PMID:9194247

  3. Dislocation sources in ordered intermetallics

    SciTech Connect

    Yoo, M.H. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.; Appel, F.; Wagner, R. [GKSS-Research Centre, Geesthacht (Germany). Inst. for Materials Research; Mecking, H. [Technical Univ. Hamburg-Harburg, Hamburg (Germany)

    1996-09-01

    An overview on the current understanding of dislocation sources and multiplication mechanisms is made for ordered intermetallic alloys of the L1{sub 2}, B2, and D0{sub 19} structures. In L1{sub 2} alloys, a large disparity of edge/screw segments in their relative mobility reduces the efficiency of a Frank-Read Type multiplication mechanism. In Fe-40%Al of the B2 structure, a variety of dislocation sources are available for <111> slip, including ones resulting from condensation of thermal vacancies. In NiAl with the relatively high APB energy, <100> dislocations may result from the dislocation decomposition reactions, the prismatic punching out from inclusion particles, and/or steps and coated layers of the surface. Internal interfaces often provide sites for dislocation multiplication, e.g., grain boundaries, sub-boundaries in Ni{sub 3}Ga, NiAl and Ti{sub 3}Al, and antiphase domain boundaries in Ti{sub 3}Al. As for the crack tip as a dislocation source, extended SISFs trailed by super-Shockley partials emanating form the cracks in Ni{sub 3}Al and Co{sub 3}Ti are discussed in view of a possible toughening mechanism.

  4. Deriving Laws from Ordering Relations

    NASA Technical Reports Server (NTRS)

    Knuth, Kevin H.

    2004-01-01

    The effect of Richard T. Cox's contribution to probability theory was to generalize Boolean implication among logical statements to degrees of implication, which are manipulated using rules derived from consistency with Boolean algebra. These rules are known as the sum rule, the product rule and Bayes Theorem, and the measure resulting from this generalization is probability. In this paper, I will describe how Cox s technique can be further generalized to include other algebras and hence other problems in science and mathematics. The result is a methodology that can be used to generalize an algebra to a calculus by relying on consistency with order theory to derive the laws of the calculus. My goals are to clear up the mysteries as to why the same basic structure found in probability theory appears in other contexts, to better understand the foundations of probability theory, and to extend these ideas to other areas by developing new mathematics and new physics. The relevance of this methodology will be demonstrated using examples from probability theory, number theory, geometry, information theory, and quantum mechanics.

  5. Ferroelectric ordering in imidazolium perchlorate

    NASA Astrophysics Data System (ADS)

    Paj?k, Z.; Czarnecki, P.; Szafra?ska, B.; Ma?uszy?ska, H.; Fojud, Z.

    2006-04-01

    Imidazolium perchlorate has been synthesized and studied over a wide range of temperatures by differential scanning calorimetry, x-ray diffraction, proton magnetic resonance, optical observation, and dielectric spectroscopy. Polymorphic solid-solid phase transitions have been disclosed at 487, 373, and 247K. The crystal structure at 298K has been determined as trigonal, space group R3m, Z =1 with a =5.484(1)Å and ? =95.18(2)°. The imidazolium cations are strongly disordered, while the perchlorate ions are well ordered. At 385K the crystal structure remains trigonal, space group R3¯m, a =5.554(1)Å and ? =95.30(2)°. Both ionic sublattices are orientationally disordered. Temperature evolution of the molecular dynamics of the imidazolium cation has been characterized. In spite of a high cationic disorder, dielectric measurements have revealed the polar properties of the crystal. It appears to be a new ferroelectric compound with the Curie point at 373K. The spontaneous polarization originates predominantly from the behavior of slightly distorted perchlorate anion.

  6. Free Triangle Orders Joshua D. Laison

    E-print Network

    Laison, Josh

    Free Triangle Orders Joshua D. Laison Department of Mathematics Colorado College 14 E. Cache La triangle orders. These are ordered sets represented by a left-to-right ordering on geometric objects con- tained in a horizontal strip in the plane. The objects are called "free triangles," and have one vertex

  7. MURDOCH UNIVERSITY BOOKSHOP Special Book Order Form

    E-print Network

    MURDOCH UNIVERSITY BOOKSHOP Special Book Order Form (Please note charges apply) Name: Phone: Mobile _____________________ Internal Account number _____________________ · Special Book orders (SBO's) are accepted on a firm sale. · Ordering from a website is not an SBO service and cannot be provided · Books ordered from Australian

  8. Optimistic Total Order in Wide Area Networks

    Microsoft Academic Search

    António Luís Pinto Ferreira De Sousa; Jose Pereira; Francisco Moura; Rui Carlos Oliveira

    2002-01-01

    Total order multicast greatly simplifies the implementa- tion of fault-tolerant services using the replicated state ma- chine approach. The additional latency of total ordering can be masked by taking advantage of spontaneous order- ing observed in LANs: A tentative delivery allows the ap- plication to proceed in parallel with the ordering protocol. The effectiveness of the technique rests on the

  9. 46 CFR Sec. 7 - Job order numbering.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...2013-10-01 2013-10-01 false Job order numbering. Sec. 7 Section 7...REPAIR CONTRACT-NSA-LUMPSUMREP Sec. 7 Job order numbering. (a) The NSA-LUMPSUMREP...Contract number shall be inserted in every job order and supplemental job order...

  10. 46 CFR Sec. 7 - Job order numbering.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...2014-10-01 2014-10-01 false Job order numbering. Sec. 7 Section 7...REPAIR CONTRACT-NSA-LUMPSUMREP Sec. 7 Job order numbering. (a) The NSA-LUMPSUMREP...Contract number shall be inserted in every job order and supplemental job order...

  11. 46 CFR Sec. 7 - Job order numbering.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...2012-10-01 2012-10-01 false Job order numbering. Sec. 7 Section 7...REPAIR CONTRACT-NSA-LUMPSUMREP Sec. 7 Job order numbering. (a) The NSA-LUMPSUMREP...Contract number shall be inserted in every job order and supplemental job order...

  12. 46 CFR Sec. 7 - Job order numbering.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Job order numbering. Sec. 7 Section 7...REPAIR CONTRACT-NSA-LUMPSUMREP Sec. 7 Job order numbering. (a) The NSA-LUMPSUMREP...Contract number shall be inserted in every job order and supplemental job order...

  13. 46 CFR Sec. 7 - Job order numbering.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...2011-10-01 2011-10-01 false Job order numbering. Sec. 7 Section 7...REPAIR CONTRACT-NSA-LUMPSUMREP Sec. 7 Job order numbering. (a) The NSA-LUMPSUMREP...Contract number shall be inserted in every job order and supplemental job order...

  14. Optimal order placement in limit order markets Rama Cont and Arseniy Kukanov

    E-print Network

    Paris-Sud XI, Université de

    by the characteristics of the order flow and queue sizes in each limit order book, as well as the structure the interplay between the state of order books, the fee structure, order flow properties and preferences milliseconds to several minutes and the mechanism through which orders are filled in the limit order book

  15. 48 CFR 552.216-74 - Task-Order and Delivery-Order Ombudsman.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...2010-10-01 2010-10-01 false Task-Order and Delivery-Order Ombudsman...Provisions and Clauses 552.216-74 Task-Order and Delivery-Order Ombudsman...b), insert the following clause: Task-Order and Delivery-Order...

  16. Visual perception of order-disorder transition

    PubMed Central

    Katkov, Mikhail; Harris, Hila; Sagi, Dov

    2015-01-01

    Our experience with the natural world, as composed of ordered entities, implies that perception captures relationships between image parts. For instance, regularities in the visual scene are rapidly identified by our visual system. Defining the regularities that govern perception is a basic, unresolved issue in neuroscience. Mathematically, perfect regularities are represented by symmetry (perfect order). The transition from ordered configurations to completely random ones has been extensively studied in statistical physics, where the amount of order is characterized by a symmetry-specific order parameter. Here we applied tools from statistical physics to study order detection in humans. Different sets of visual textures, parameterized by the thermodynamic temperature in the Boltzmann distribution, were designed. We investigated how much order is required in a visual texture for it to be discriminated from random noise. The performance of human observers was compared to Ideal and Order observers (based on the order parameter). The results indicated a high consistency in performance across human observers, much below that of the Ideal observer, but well-approximated by the Order observer. Overall, we provide a novel quantitative paradigm to address order perception. Our findings, based on this paradigm, suggest that the statistical physics formalism of order captures regularities to which the human visual system is sensitive. An additional analysis revealed that some order perception properties are captured by traditional texture discrimination models according to which discrimination is based on integrated energy within maps of oriented linear filters.

  17. Petroleum: The Petroleum (Carbon Disulphide) Order, 1958 

    E-print Network

    Agnew, W.G.

    1958-01-01

    The Order in Council now revoked by Article 2 of this Order when originally made applied to bisulphide of carbon the provisions of the Acts repealed and replaced by the Petroleum (Consolidation) Act, 1928, relating to the ...

  18. 40 CFR 164.123 - Emergency order.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...2013-07-01 false Emergency order. 164...of Environment ENVIRONMENTAL PROTECTION AGENCY... § 164.123 Emergency order. (a) Whenever the Environmental Appeals Board determines that an emergency exists that...

  19. 40 CFR 164.123 - Emergency order.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...2014-07-01 false Emergency order. 164...of Environment ENVIRONMENTAL PROTECTION AGENCY... § 164.123 Emergency order. (a) Whenever the Environmental Appeals Board determines that an emergency exists that...

  20. 40 CFR 164.123 - Emergency order.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...2012-07-01 false Emergency order. 164...of Environment ENVIRONMENTAL PROTECTION AGENCY... § 164.123 Emergency order. (a) Whenever the Environmental Appeals Board determines that an emergency exists that...

  1. Fuzzy Multiple Heuristic Orderings for Examination Timetabling

    E-print Network

    Aickelin, Uwe

    Fuzzy Multiple Heuristic Orderings for Examination Timetabling Hishammuddin Asmuni1 , Edmund K Heidelberg 2005 #12;Fuzzy Multiple Heuristic Orderings for Examination Timetabling 335 Over the years], hyper- heuristics [13] and various metaheuristic approaches including greedy local search [19], [23

  2. these pages are in correct order

    E-print Network

    We ?rst list in alphabetical order 10 judg- ments we ... graphs, describe each brie?y, then order them by our ability to perform them ... ELEMENTARY GRAPHICAL PERCEPTION. TASKS ..... y early statistical experiments were run on agricultural.

  3. 20 CFR 655.121 - Job orders.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...2011-04-01 2011-04-01 false Job orders. 655.121 Section 655.121 Employees' Benefits EMPLOYMENT AND TRAINING...States (H-2A Workers) Prefiling Procedures § 655.121 Job orders. (a) Area of intended...

  4. 20 CFR 655.121 - Job orders.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...2013-04-01 2013-04-01 false Job orders. 655.121 Section 655.121 Employees' Benefits EMPLOYMENT AND TRAINING...States (H-2A Workers) Prefiling Procedures § 655.121 Job orders. (a) Area of intended...

  5. 20 CFR 655.121 - Job orders.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...2012-04-01 2012-04-01 false Job orders. 655.121 Section 655.121 Employees' Benefits EMPLOYMENT AND TRAINING...States (H-2A Workers) Prefiling Procedures § 655.121 Job orders. (a) Area of intended...

  6. 20 CFR 655.121 - Job orders.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...2014-04-01 2014-04-01 false Job orders. 655.121 Section 655.121 Employees' Benefits EMPLOYMENT AND TRAINING...States (H-2A Workers) Prefiling Procedures § 655.121 Job orders. (a) Area of intended...

  7. 20 CFR 655.121 - Job orders.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ...2010-04-01 2010-04-01 false Job orders. 655.121 Section 655.121 Employees' Benefits EMPLOYMENT AND TRAINING...States (H-2A Workers) Prefiling Procedures § 655.121 Job orders. (a) Area of intended...

  8. 7 CFR 917.100 - Order.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...Nuts), DEPARTMENT OF AGRICULTURE FRESH PEARS AND PEACHES GROWN IN CALIFORNIA Rules and Regulations Definitions § 917.100 Order. Order ...part 917), regulating the handling of fresh pears and peaches grown in the...

  9. 28 CFR 2.58 - Prior orders.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...Judicial Administration DEPARTMENT OF JUSTICE PAROLE, RELEASE, SUPERVISION AND RECOMMITMENT OF PRISONERS, YOUTH OFFENDERS, AND JUVENILE DELINQUENTS United States Code Prisoners and Parolees § 2.58 Prior orders. Any order of...

  10. Prioritization and control of order picking system

    E-print Network

    Kanburapa, Prachyathit

    2013-01-01

    Order Picking System (OPS) efficiency at a warehouse was studied with the goal of reducing production order lead time to 8 hours. Current material flow system and strategy were studied through interviews with personnel ...

  11. Contact Geometry of Second Order I

    Microsoft Academic Search

    Keizo Yamaguchi

    Classical theory for systems of the first order partial differential equations for a scalar function can be rephrased as the\\u000a submanifold theory of contact manifolds (geometric first order jet spaces). In the same spirit, we will develop the geometric\\u000a theory of systems of partial differential equations of second order for a scalar function as the Contact Geometry of Second Order,

  12. Practical tools for third order cosmological perturbations

    SciTech Connect

    Christopherson, Adam J.; Malik, Karim A., E-mail: a.christopherson@qmul.ac.uk, E-mail: k.malik@qmul.ac.uk [Astronomy Unit, School of Mathematical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS (United Kingdom)

    2009-11-01

    We discuss cosmological perturbation theory at third order, deriving the gauge transformation rules for metric and matter perturbations, and constructing third order gauge invariant quantities. We present the Einstein tensor components, the evolution equations for a perfect fluid, and the Klein-Gordon equation at third order, including scalar, vector and tensor perturbations. In doing so, we also give all second order tensor components and evolution equations in full generality.

  13. Algorithmic Trading Patterns in Xetra Orders

    Microsoft Academic Search

    Johannes Prix; Otto Loistl; Michael Huetl

    2007-01-01

    Computerized trading controlled by algorithms – “Algorithmic Trading” – has become a fashionable term in investment banking. We investigate a set of Xetra order data to find traces of algorithmic trading by studying the lifetimes of cancelled orders. Even though it is widely agreed that an algorithm must randomize its order activities to avoid exploitation by other traders, we still

  14. High Order Schemes for CFD: A Review

    Microsoft Academic Search

    Juan Cheng; Chi-Wang Shu

    Over the past two decades there have been many research activities in the design and ap- plication of high order accurate numerical methods in computational uid dynamics (CFD). High order methods are especially desirable for simulating o ws with complicated solution structures. In this paper we give a review on the development and application of several classes of high order

  15. Methodology, Birth Order, Intelligence, and Personality.

    ERIC Educational Resources Information Center

    Michalski, Richard L.; Shackelford, Todd K.

    2001-01-01

    Critiques recent research on the effects of birth order on intelligence and personality, which found that the between-family design revealed that birth order negatively related to intelligence, while the within-family design revealed that birth order was unrelated to intelligence. Suggests that it may not be intelligence that co-varies with birth…

  16. Half Orders of Magnitude Jerry R. Hobbs

    E-print Network

    Hobbs, Jerry R.

    Half Orders of Magnitude Jerry R. Hobbs USC Information Sciences Institute Marina del Rey with precise values for quantities we encounter in everyday life. We can easily come up with order-of-magnitude. However, people find it nearly as easy to come up with half-order-of- magnitude estimates

  17. Half Orders of Magnitude Jerry R. Hobbs

    E-print Network

    Hobbs, Jerry R.

    Half Orders of Magnitude Jerry R. Hobbs USC Information Sciences Institute Marina del Rey with precise values for quantities we encounter in everyday life. We can easily come up with order­of­magnitude. However, people find it nearly as easy to come up with half­order­of­ magnitude estimates

  18. Abel's Theorem Simplifies Reduction of Order

    ERIC Educational Resources Information Center

    Green, William R.

    2011-01-01

    We give an alternative to the standard method of reduction or order, in which one uses one solution of a homogeneous, linear, second order differential equation to find a second, linearly independent solution. Our method, based on Abel's Theorem, is shorter, less complex and extends to higher order equations.

  19. Defects and order in liquid crystal phases

    Microsoft Academic Search

    Shilpa Jain

    1999-01-01

    This thesis investigates the partial destruction of ordering in liquid crystalline systems due to the influence of defects and thermal fluctuations. The systems under consideration are hexagonal columnar crystals with crystalline order perpendicular to the columns, and two-dimensional smectics with order perpendicular to the layers. We first study the possibility of reentrant melting of a hexagonal columnar crystal of flexible

  20. Robust Higher Order Statistics Max Welling

    E-print Network

    Welling, Max

    Robust Higher Order Statistics Max Welling School of Information and Computer Science University order statistics, like kurtosis, which are used in algo- rithms for independent components analysis, is a much more suitable statistic for scale than the second order moment. This process of sub- tracting

  1. Robust Higher Order Statistics Max Welling

    E-print Network

    Welling, Max

    Robust Higher Order Statistics Max Welling School of Information and Computer Science University order statistics, like kurtosis, which are used in algo­ rithms for independent components analysis.e. the variance, is a much more suitable statistic for scale than the second order moment. This process of sub

  2. Order Statistics from the Gamma Distribution

    Microsoft Academic Search

    Shanti S. Gupta

    1960-01-01

    This paper deals with order statistics from a gamma or ? (Pearson Type III) distribution. Expressions are derived for the moments of an order statistic and for the covariance between two order statistics. A table of moments (about the origin as well as the mean) is presented. Equations are derived which are used to solve for the percentage points of

  3. TIGHT BOUNDS ON EXPECTED ORDER STATISTICS

    E-print Network

    Bertsimas, Dimitris

    TIGHT BOUNDS ON EXPECTED ORDER STATISTICS DIIIMMMIIITTTRRRIIISSS BEEERRRTTTSSSIIIMMMAAASSS Sloan@nus.edu.sg In this article, we study the problem of finding tight bounds on the expected value of the kth-order statistic E of the highest-order statistic E @Xn:n# can be computed with a bisection search algo- rithm+ An extremal discrete

  4. Security and Privacy for Partial Order Time

    Microsoft Academic Search

    S. W. Smith; J. D. Tygar

    1994-01-01

    Partial order time expresses issues central to many problems in asynchronous distributed systems, but suffers from inherent security and privacy risks. Secure partial order clocks provide a general methodto developapplication protocolsthattransparentlyprotectagainst these risks. Ourprevious Signed Vector Timestamp protocol provides a partial order time service with some security: no one can forge dependence on an honest process. However, that protocol still

  5. Liquidity Shocks and Order Book Dynamics

    Microsoft Academic Search

    Bruno Biais; Pierre-Olivier Weill

    2009-01-01

    We propose a dynamic competitive equilibrium model of limit order trading, based on the premise that investors cannot monitor markets continuously. We study how limit order markets absorb transient liquidity shocks, which occur when a significant fraction of investors lose their willingness and ability to hold assets. We characterize the equilibrium dynamics of market prices, bid-ask spreads, order submissions and

  6. Optimal execution strategies in limit order books

    E-print Network

    Paris-Sud XI, Université de

    Optimal execution strategies in limit order books with general shape functions Aur´elien Alfonsi order book (LOB). We build on the resilience model proposed by Obizhaeva and Wang (2005) but allow 20, 2009 Abstract: We consider optimal execution strategies for block market orders placed in a limit

  7. On initial segments of computable linear orders

    E-print Network

    On initial segments of computable linear orders Richard J. Coles, Rod Downey and Bakhadyr. of Computer Science University of Auckland New Zealand Abstract We show there is a computable linear order with a \\Pi 0 2 initial seg­ ment that is not isomorphic to any computable linear order. 1 Introduction

  8. Ordering Tax Transcripts A. Online Request

    E-print Network

    Wagner, Diane

    Ordering Tax Transcripts A. Online Request Go to: www.irs.gov In the "Online Services" section, select "Order a Tax Return or Account Transcript". Click "Order a Transcript" Provide tax filer's SSN "Return Transcript" and the appropriate year in "Tax Year" field. If successfully linked, tax filers can

  9. 7 Innovation Approach to Reduced Order Estimation

    Microsoft Academic Search

    Ali Jalali; Parviz Famouri

    In this chapter we will rederive some of the results that have been previously obtained in Chapter three using a concept of\\u000a “reduced order innovation process.” The concept of “reduced order innovation process” we feel captures the qualitative essence\\u000a of how useful information is extracted from the given measurements when a reduced order estimator is used.

  10. A partial ordering of rank densities

    Microsoft Academic Search

    Michael Proschan; Frederick Leysieffer

    1992-01-01

    A function f([pi]) on the set of permutations of {1, 2, ..., n} is called arrangement increasing (AI) if it increases each time we transpose a pair of coordinates in descending order, i < j and [pi]i > [pi]j, putting them in ascending order. We define and develop a partial ordering <=AI on densities of rank vectors in terms of

  11. Characteristics of the order flow through an electronic open limit order book

    Microsoft Academic Search

    Philip Brown; Nathanial Thomson; David Walsh

    1999-01-01

    We estimate and examine certain characteristics of the order flow through an electronic open limit order book, using order (not trade) data. In doing this, we bring out new evidence on order flow from a market with microstructure different from that of the NYSE. We find that the proportion of informed orders is less than 10%, lower than previous estimates.

  12. Photonic Phase Control of Magnetic Oxides

    Microsoft Academic Search

    Y. Okimoto; Y. Tokura; Y. Tomioka; Y. Onose; Y. Otsuka; K. Miyano

    1998-01-01

    Unconventional optical responses have been revealed for the perovskite manganese oxide, Pr1-xCaxMnO3, which is known to undergo the insulatormetal (I-M) transition relevant to the magnetic field induced melting of the charge-ordered (CO) state. Optical conductivity spectrum is drastically modified over 0–1 eV from a gap-like feature into a metallic band with application of magnetic field of 7 T. It was

  13. Strong gravitational force induced by static electromagnetic fields

    E-print Network

    B. V. Ivanov

    2004-07-13

    It is argued that static electric or magnetic fields induce Weyl-Majumdar-Papapetrou solutions for the metric of spacetime. Their gravitational acceleration includes a term many orders of magnitude stronger than usual perturbative terms. It gives rise to a number of effects, which can be detected experimentally. Four electrostatic and four magnetostatic examples of physical set-ups with simple symmetries are proposed. The different ways in which mass sources enter and complicate the pure electromagnetic picture are described.

  14. Magnetoelectric interactions and phase transitions in a new class of multiferroics with improper electric polarization

    Microsoft Academic Search

    A. K. Zvezdin; A. A. Mukhin

    2008-01-01

    Symmetry analysis of magnetoelectric interactions in rare-earth orthoferrites and orthochromites has been performed. It has\\u000a been shown that symmetry allows the appearance of spontaneous electric polarization or the magnetic-field-induced polarization\\u000a in the region of antiferromagnetic (centro-asymmetric) ordering of the rare-earth ions. The analysis reveals a number of pronounced\\u000a anomalies in the behavior of the electric polarization at the metamagnetic and

  15. Nature of the liquid crystalline phase transitions in the cesium pentadecafluorooctanoate (CsPFO)-water system: The nematic-to-isotropic transition

    Microsoft Academic Search

    K. W. Jolley; M. H. Smith; N. Boden; J. R. Henderson

    2001-01-01

    Deuterium NMR spectroscopy of 2H2O has been used to monitor the magnetic-field-induced order on approaching a transition to a nematic phase in isotropic solutions of disklike micelles of cesium pentadecafluorooctanoate. Highly accurate data on the phase boundaries and spinodals have been obtained for solutions with volume fraction concentration phi between 0.078 and 0.201. The quantity TIN-T*, where T* is the

  16. Competing orders in the cuprate superconductors

    NASA Astrophysics Data System (ADS)

    Zhang, Ying

    When the superconducting order in a doped cuprate system is suppressed, for example by magnetic field, impurities, finite temperature or less optimal doping condition, various competing orders are revealed. This thesis contains the theoretical analysis of these competing orders, especially the analysis of the quantum phase transitions from a d-wave superconductor to a superconductor featuring a certain other order. Such orders can be divided into two types according to whether or not they carry non-zero net momentum Q. We classify and analyze all order parameters with Q = 0 on the basis of group-theoretic and symmetry arguments. Thereafter, by a renormalization group analysis, we identify that among all these orders the fluctuations of dx2 - y2 + idxy paring order might strongly damp the nodal quasiparticles of the cuprate superconductor, while leaving antinodal quasiparticles undamped. We also study order parameters with Q ? 0, which include spin and charge density wave orders. For exact nesting case, fluctuations of these two orders also give rise to nodal quasiparticle damping. We also examine the influence of a magnetic field on the spin and charge density waves. We argue that the underdoped cuprates might undergo a second order phase transition into a region where superconducting order coexists with long-range magnetic order (and hence charge order). The transition might be driven by lowering the doping or increasing the magnetic field, all of which decrease the spin gap and affect the excitation spectrum. Our quantum field theory for the transition takes into account the quantum fluctuation of spin order, while keeping superconducting order a mean-field quantity that serves as a tuning parameter by coupling to spin order. Complete numerical solutions of a self-consistent large-N theory provide detailed information on the phase diagram and the spatial structure of the dynamic spin spectrum. We also compute the pinning of charge density order by the vortices where the spin order dynamically fluctuates. Emerging experimental evidence has strongly supported our theory and the subsequent predictions.

  17. Pseudo-High-Order Symplectic Integrators

    E-print Network

    J. E. Chambers; M. A. Murison

    1999-10-14

    Symplectic N-body integrators are widely used to study problems in celestial mechanics. The most popular algorithms are of 2nd and 4th order, requiring 2 and 6 substeps per timestep, respectively. The number of substeps increases rapidly with order in timestep, rendering higher-order methods impractical. However, symplectic integrators are often applied to systems in which perturbations between bodies are a small factor of the force due to a dominant central mass. In this case, it is possible to create optimized symplectic algorithms that require fewer substeps per timestep. This is achieved by only considering error terms of order epsilon, and neglecting those of order epsilon^2, epsilon^3 etc. Here we devise symplectic algorithms with 4 and 6 substeps per step which effectively behave as 4th and 6th-order integrators when epsilon is small. These algorithms are more efficient than the usual 2nd and 4th-order methods when applied to planetary systems.

  18. Ionic Conductivity of Block Copolymer Electrolytes in the Vicinity of Order?Disorder and Order?Order Transitions

    SciTech Connect

    Wanakule, Nisita S.; Panday, Ashoutosh; Mullin, Scott A.; Gann, Eliot; Hexemer, Alex; Balsara, Nitash P.; (UCB); (LBNL)

    2009-09-15

    Order-order and order-disorder phase transitions in mixtures of poly(styrene-block-ethylene oxide) (SEO) copolymers and lithium bis(trifluoromethylsulfonimide) (LiTFSI), a common lithium salt used in polymer electrolytes, were studied using a combination of small-angle X-ray scattering (SAXS), birefringence, and ac impedance spectroscopy. The SEO/LiTFSI mixtures exhibit lamellar, hexagonally packed cylinders, and gyroid microphases. The molecular weight of the blocks and the salt concentration was adjusted to obtain order-order and order-disorder transition temperatures within the available experimental window. The ionic conductivities of the mixtures, normalized by the ionic conductivity of a 20 kg/mol homopolymer PEO sample at the salt concentration and temperature of interest, were independent of temperature, in spite of the presence of the above-mentioned phase transitions.

  19. Two variants of minimum discarded fill ordering

    SciTech Connect

    D'Azevedo, E.F. (Oak Ridge National Lab., TN (USA)); Forsyth, P.A.; Tang, Wei-Pai (Waterloo Univ., ON (Canada). Dept. of Computer Science)

    1991-01-01

    It is well known that the ordering of the unknowns can have a significant effect on the convergence of Preconditioned Conjugate Gradient (PCG) methods. There has been considerable experimental work on the effects of ordering for regular finite difference problems. In many cases, good results have been obtained with preconditioners based on diagonal, spiral or natural row orderings. However, for finite element problems having unstructured grids or grids generated by a local refinement approach, it is difficult to define many of the orderings for more regular problems. A recently proposed Minimum Discarded Fill (MDF) ordering technique is effective in finding high quality Incomplete LU (ILU) preconditioners, especially for problems arising from unstructured finite element grids. Testing indicates this algorithm can identify a rather complicated physical structure in an anisotropic problem and orders the unknowns in the preferred'' direction. The MDF technique may be viewed as the numerical analogue of the minimum deficiency algorithm in sparse matrix technology. At any stage of the partial elimination, the MDF technique chooses the next pivot node so as to minimize the amount of discarded fill. In this work, two efficient variants of the MDF technique are explored to produce cost-effective high-order ILU preconditioners. The Threshold MDF orderings combine MDF ideas with drop tolerance techniques to identify the sparsity pattern in the ILU preconditioners. These techniques identify an ordering that encourages fast decay of the entries in the ILU factorization. The Minimum Update Matrix (MUM) ordering technique is a simplification of the MDF ordering and is closely related to the minimum degree algorithm. The MUM ordering is especially for large problems arising from Navier-Stokes problems. Some interesting pictures of the orderings are presented using a visualization tool. 22 refs., 4 figs., 7 tabs.

  20. Microscopic evidence for magnetic-phase coexistence in the intermetallic compound Nd7Rh3

    NASA Astrophysics Data System (ADS)

    Rayaprol, S.; Siruguri, V.; Hoser, A.; Ritter, C.; Sampathkumaran, E. V.

    2014-10-01

    The intermetallic compound Nd7Rh3, which shows two magnetic transitions, one at 32 K and another around 16 K, has been known to exhibit a magnetic-field induced first-order magnetic phase transition (FOPT) at low temperatures. Using neutron diffraction we tracked the evolution of the magnetic features as a function of temperature and external magnetic field across the two transition temperatures. We provide evidence for the existence of both antiferromagnetism and ferromagnetism below 20 K. Notably the results reveal concrete evidence for the partial persistence of the high-field magnetic state at 2 K after cycling through the magnetic-field-induced magnetic transition, thereby offering microscopic evidence for magnetic coexistence phenomenon in this intermetallic compound.

  1. Quasi-Fibonacci Numbers of Order 11

    NASA Astrophysics Data System (ADS)

    Witu?a, Roman; S?ota, Damian

    2007-08-01

    In this paper we introduce and investigate the so-called quasi-Fibonacci numbers of order 11 . These numbers are defined by five conjugate recurrence equations of order five. We study some relations and identities concerning these numbers. We present some applications to the decomposition of some polynomials. Many of the identities presented here are the generalizations of the identities characteristic for general recurrence sequences of order three given by Rabinowitz.

  2. Stabilization by reduced-order controllers

    Microsoft Academic Search

    Malcolm C. Smith

    1991-01-01

    A recent result by A. Linnemann (Syst. Contr. Lett., vol.11, p.27-32, 1988) gives conditions under which a continuous-time single-loop plant of order n can be stabilized by a reduced-order controller. Specifically, if the Euclidean algorithm is applied to the numerator and denominator polynomials of the transfer function and one of the remainders is a kth-order Hurwitz polynomial, then a stabilizing

  3. Exact significance test for Markov order

    NASA Astrophysics Data System (ADS)

    Pethel, S. D.; Hahs, D. W.

    2014-02-01

    We describe an exact significance test of the null hypothesis that a Markov chain is nth order. The procedure utilizes surrogate data to yield an exact test statistic distribution valid for any sample size. Surrogate data are generated using a novel algorithm that guarantees, per shot, a uniform sampling from the set of sequences that exactly match the nth order properties of the observed data. Using the test, the Markov order of Tel Aviv rainfall data is examined.

  4. Econometric models of limit-order executions

    Microsoft Academic Search

    Andrew W. Lo; A. Craig MacKinlay; June Zhang

    2002-01-01

    We develop and estimate an econometric model of limit-order execution times using survival analysis and actual limit-order data. We estimate versions for time-to-first-fill and time-to-completion for both buy and sell limit orders, and incorporate the effects of explanatory variables such as the limit price, limit size, bid\\/offer spread, and market volatility. Execution times are very sensitive to the limit price,

  5. Preschoolers Can Attribute Second-Order Beliefs

    Microsoft Academic Search

    Kate Sullivan; Deborah Zaitchik; Helen Tager-Flusberg

    1994-01-01

    The ability to attribute 2nd-order mental states was investigated in 87 children drawn from pre-school, kindergarten, 1st-grade, and 2nd-grade classes. Children received 4 stories, 2 standard and 2 new, designed to test their understanding of 2nd-order mental states. The standard stories were modified versions of J. Perner and H. Wimmer's (1985) 2nd-order task. The new stories were made significantly simpler

  6. Two-dimensional order and disorder thermofields

    SciTech Connect

    Belvedere, L. V. [Instituto de Fisica - Universidade Federal Fluminense, Av. Litora circumflex nea S/N, Boa Viagem Niteroi, CEP 24210-340 Rio de Janeiro (Brazil)

    2006-11-15

    The main objective of this paper was to obtain the two-dimensional order and disorder thermal operators using the Thermofield Bosonization formalism. We show that the general property of the two-dimensional world according with the bosonized Fermi field at zero temperature can be constructed as a product of an order and a disorder variables which satisfy a dual field algebra holds at finite temperature. The general correlation functions of the order and disorder thermofields are obtained.

  7. Convergence and Ordering of Kohonen's Batch Map

    Microsoft Academic Search

    Yizong Cheng

    1997-01-01

    The convergence and ordering of Kohonen's batch-mode self-organizing map with Heskes and Kappen's (1993) winner selection are proved. Selim and Ismail's (1984) objective function for k-means clustering is generalized in the convergence proof of the self-organizing map. It is shown that when the neighborhood relation is doubly decreasing, order in the map is preserved. An unordered map becomes ordered when

  8. An overview of task order 10

    SciTech Connect

    Rousculp, Christopher L [Los Alamos National Laboratory

    2011-01-12

    Task Order 10 formalizes a collaboration in high explosive pulsed power (HEPP) experiments between LANL and VNIIEF. The focus is the VNIIEF disk explosive magnetic generator (DEMG) technology. The task order outlines a sequence of tasks and deliverables culminating in an experiment which takes place in the US utilizing US explosives and a Russian DEMG. This talk summarizes task order 10. It gives a brief history and present status in terms of the proposed high pressure EOS experiment (ALT-3).

  9. The Twelve Soil Orders - Soil Taxonomy

    NSDL National Science Digital Library

    This University of Idaho website discusses the twelve orders of soils, and provides images that illustrate the distribution, properties, and use of the soil orders. It provides general information on each of the twelve orders with a description, a U.S. map showing soil locations, and pictures of the soil type. A Global Distribution Map indicates locations of each soil type throughout the world.

  10. Synchronization of fractional order complex dynamical networks

    NASA Astrophysics Data System (ADS)

    Wang, Yu; Li, Tianzeng

    2015-06-01

    In this letter the synchronization of complex dynamical networks with fractional order chaotic nodes is studied. A fractional order controller for synchronization of complex network is presented. Some new sufficient synchronization criteria are proposed based on the Lyapunov stability theory and the LaSalle invariance principle. These synchronization criteria can apply to an arbitrary fractional order complex network in which the coupling-configuration matrix and the inner-coupling matrix are not assumed to be symmetric or irreducible. It means that this method is more general and effective. Numerical simulations of two fractional order complex networks demonstrate the universality and the effectiveness of the proposed method.

  11. Studies of ordering in small particles

    SciTech Connect

    Herr, U. [Univ. of Illinois, Urbana, IL (United States); [Univ. of Augsburg (Germany). Inst. of Physics; Pollack, M.; Olynick, D.L.; Gibson, J.M.; Averback, R.S. [Univ. of Illinois, Urbana, IL (United States)

    1996-12-31

    Disordered clusters of the intermetallic compounds Ni{sub 3}Al and Cu{sub 3}Au have been produced using a high pressure sputtering technique. The clusters are either embedded in a film or studied, in-situ in a UHV electron microscope. The evolution of the ordered structure upon annealing is studied. Using a scanning transmission electron microscope, electron diffraction is obtained from individual clusters. Partial ordering is observed in Cu{sub 3}Au clusters which have been annealed below the bulk order-disorder transition temperature. Under the experimental conditions, only cluster with sizes of 10--15 nm or larger show ordering.

  12. Optical method of atomic ordering estimation

    SciTech Connect

    Prutskij, T. [Instituto de Ciencias, BUAP, Privada 17 Norte, No 3417, col. San Miguel Huyeotlipan, Puebla, Pue. (Mexico); Attolini, G. [IMEM/CNR, Parco Area delle Scienze 37/A - 43010, Parma (Italy); Lantratov, V.; Kalyuzhnyy, N. [Ioffe Physico-Technical Institute, 26 Polytekhnicheskaya, St Petersburg 194021, Russian Federation (Russian Federation)

    2013-12-04

    It is well known that within metal-organic vapor-phase epitaxy (MOVPE) grown semiconductor III-V ternary alloys atomically ordered regions are spontaneously formed during the epitaxial growth. This ordering leads to bandgap reduction and to valence bands splitting, and therefore to anisotropy of the photoluminescence (PL) emission polarization. The same phenomenon occurs within quaternary semiconductor alloys. While the ordering in ternary alloys is widely studied, for quaternaries there have been only a few detailed experimental studies of it, probably because of the absence of appropriate methods of its detection. Here we propose an optical method to reveal atomic ordering within quaternary alloys by measuring the PL emission polarization.

  13. Pi Bond Orders and Bond Lengths

    ERIC Educational Resources Information Center

    Herndon, William C.; Parkanyi, Cyril

    1976-01-01

    Discusses three methods of correlating bond orders and bond lengths in unsaturated hydrocarbons: the Pauling theory, the Huckel molecular orbital technique, and self-consistent-field techniques. (MLH)

  14. CCII based fractional filters of different orders.

    PubMed

    Soltan, Ahmed; Radwan, Ahmed G; Soliman, Ahmed M

    2014-03-01

    This paper aims to generalize the design of continuous-time filters to the fractional domain with different orders and validates the theoretical results with two different CCII based filters. In particular, the proposed study introduces the generalized formulas for the previous fractional-order analysis of equal orders. The fractional-order filters enhance the design flexibility and prove that the integer-order performance is a very narrow subset from the fractional-order behavior due to the extra degrees of freedom. The general fundamentals of these filters are presented by calculating the maximum and minimum frequencies, the half power frequency and the right phase frequency which are considered a critical issue for the filter design. Different numerical solutions for the generalized fractional order low pass filters with two different fractional order elements are introduced and verified by the circuit simulations of two fractional-order filters: Kerwin-Huelsman-Newcomb (KHN) and Tow-Tomas CCII-based filters, showing great matching. PMID:25685483

  15. Birth order effect on childhood food allergy.

    PubMed

    Kusunoki, Takashi; Mukaida, Kumiko; Morimoto, Takeshi; Sakuma, Mio; Yasumi, Takahiro; Nishikomori, Ryuta; Heike, Toshio

    2012-05-01

    Higher birth order is associated with a smaller risk of allergy (birth order effect). The purpose of this study was to compare the significance of the birth order effect on the prevalence of specific allergic diseases [bronchial asthma (BA), atopic dermatitis (AD), allergic rhinitis (AR), allergic conjunctivitis (AC), and food allergy (FA)] among schoolchildren. A questionnaire survey dealing with the prevalence of allergic diseases was administered to the parents of 14,669 schoolchildren aged 7-15?yr. Based on the data, the prevalence of each allergic disease was compared according to birth order (1st, 2nd, and 3rd or later). Multiple regression analysis was performed to test the significance of the differences. There was no significant difference in the prevalence of BA or AD according to birth order. The prevalence of AR, AC, and FA decreased significantly as birth order increased. The prevalence of FA among those with 1st, 2nd, and 3rd or later birth order was 4.0%, 3.4%, and 2.6%, respectively (p?=?0.01). With respect to symptoms in infancy, the prevalence of wheeze increased significantly and that of FA and eczema in infancy decreased significantly as birth order increased. The present data show a significant birth order effect on FA. The effect was also observed for the prevalence of FA and eczema in infancy. These data support the concept of early, non-allergen-specific programming of IgE-mediated immunity. PMID:22300402

  16. Higher order mechanics on graded bundles

    NASA Astrophysics Data System (ADS)

    Bruce, Andrew James; Grabowska, Katarzyna; Grabowski, Janusz

    2015-05-01

    In this paper we develop a geometric approach to higher order mechanics on graded bundles in both, the Lagrangian and Hamiltonian formalism, via the recently discovered weighted algebroids. We present the corresponding Tulczyjew triple for this higher order situation and derive in this framework the phase equations from an arbitrary (also singular) Lagrangian or Hamiltonian, as well as the Euler–Lagrange equations. As important examples, we geometrically derive the classical higher order Euler–Lagrange equations and analogous reduced equations for invariant higher order Lagrangians on Lie groupoids.

  17. Chaos in a Fractional Order Chua System

    NASA Technical Reports Server (NTRS)

    Lorenzo, Carl F.; Hartley, Tom T.; Qammar, Helen Killory

    1996-01-01

    This report studies the effects of fractional dynamics in chaotic systems. In particular, Chua's system is modified to include fractional order elements. Varying the total system order incrementally from 2.6 to 3.7 demonstrates that systems of 'order' less than three can exhibit chaos as well as other nonlinear behavior. This effectively forces a clarification of the definition of order which can no longer be considered only by the total number of differentiations or by the highest power of the Laplace variable.

  18. SECOND{ORDER AND HIGHER{ORDER PERTURBATIONS OF TRAVEL TIME IN ISOTROPIC AND ANISOTROPIC MEDIA

    E-print Network

    Cerveny, Vlastislav

    SECOND{ORDER AND HIGHER{ORDER PERTURBATIONS OF TRAVEL TIME IN ISOTROPIC AND ANISOTROPIC MEDIA Lud derivatives of travel time with respect to model parameters are re- ferred to as perturbations. Explicit equations for the second{order and higher{order perturbations of travel time in both isotropic

  19. Commencement DVD Order Form I want to order: (please check appropriate boxes)

    E-print Network

    Bertini, Robert L.

    Commencement DVD Order Form I want to order: (please check appropriate boxes) DVD and Contribution $5.00 (if not checked, you will have to pick up your DVD from the PSU Box Office) Student Info: Name are final. Money must be paid to the PSU Box Office. Commencement DVD Order Form I want to order: (please

  20. IntroductionIntroduction Zero-order basins are contributors to 1st-order systems,

    E-print Network

    IntroductionIntroduction Zero-order basins are contributors to 1st-order systems, including all included 6363 unmanaged zero-order basins in headwater areas of the Coquille River Basin, in lands and study sites. Figure 1. Zero-order basin geomorphology and plot set-up. ResultsResults I identified 138

  1. Order, chaos and nuclear dynamics: An introduction

    SciTech Connect

    Swiatecki, W.J.

    1990-08-01

    This is an introductory lecture illustrating by simple examples the anticipated effect on collective nuclear dynamics of a transition from order to chaos in the motions of nucleons inside an idealized nucleus. The destruction of order is paralleled by a transition from a rubber-like to a honey-like behaviour of the independent-particle nuclear model. 10 refs., 6 figs.

  2. Reading Achievement, Birth Order and Family Size.

    ERIC Educational Resources Information Center

    Hatzitheologou, E.

    1997-01-01

    Examined the relationship between reading achievement and birth order in 503 Greek children. Found that birth order was not related to vocabulary knowledge or reading comprehension at second grade, but total reading achievement and reading comprehension were higher for first- and second-born sixth graders than for later-born sixth graders. (KB)

  3. 7 CFR 29.2287 - Order (case).

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 2014-01-01 false Order (case). 29.2287 Section 29.2287 Agriculture Regulations of the Department of Agriculture...Virginia Fire-Cured Tobacco (u.s. Type 21) § 29.2287 Order (case). The state of tobacco with...

  4. 7 CFR 29.2287 - Order (case).

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 2012-01-01 false Order (case). 29.2287 Section 29.2287 Agriculture Regulations of the Department of Agriculture...Virginia Fire-Cured Tobacco (u.s. Type 21) § 29.2287 Order (case). The state of tobacco with...

  5. 7 CFR 29.2287 - Order (case).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 2010-01-01 false Order (case). 29.2287 Section 29.2287 Agriculture Regulations of the Department of Agriculture...Virginia Fire-Cured Tobacco (u.s. Type 21) § 29.2287 Order (case). The state of tobacco with...

  6. 7 CFR 29.2287 - Order (case).

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 2013-01-01 false Order (case). 29.2287 Section 29.2287 Agriculture Regulations of the Department of Agriculture...Virginia Fire-Cured Tobacco (u.s. Type 21) § 29.2287 Order (case). The state of tobacco with...

  7. 7 CFR 29.2287 - Order (case).

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 2011-01-01 false Order (case). 29.2287 Section 29.2287 Agriculture Regulations of the Department of Agriculture...Virginia Fire-Cured Tobacco (u.s. Type 21) § 29.2287 Order (case). The state of tobacco with...

  8. Variable Affix Order: Grammar and Learning

    ERIC Educational Resources Information Center

    Ryan, Kevin M.

    2010-01-01

    While affix ordering often reflects general syntactic or semantic principles, it can also be arbitrary or variable. This article develops a theory of morpheme ordering based on local morphotactic restrictions encoded as weighted bigram constraints. I examine the formal properties of morphotactic systems, including arbitrariness, nontransitivity,…

  9. Texas Union Pizza Order Form ROOM RESERVED ______________________________________________________

    E-print Network

    Jefferys, William

    #12;#12;Texas Union Pizza Order Form ROOM RESERVED: ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ ________________________________________________________________________________________________ Pick-up All orders are to be picked up at the Texas Union Hospitality Center desk in the south end West with the Texas Union Policies and Procedures. I understand that I will be held responsible for any debts incurred

  10. Automatic Model-Order Selection for PCA

    Microsoft Academic Search

    Michel Sarkis; Zaher Dawy; Florian Obermeier; Klaus Diepold

    2006-01-01

    Determining the model-order of a given data set is an important task in signal analysis. Principal Component Analysis (PCA) can be used for this purpose if there is a criterion upon which the correct order can be chosen. In this work, we propose a new and simple technique to determine automatically the rank of a PCA model. Tested with simulated

  11. Rapid Sampling for Visualizations with Ordering Guarantees

    E-print Network

    Williams, Brian C.

    . For instance, our algorithms can be used to generate an approximate visualiza- tion of a bar chart very rapidly to generate the visualizations with ordering guarantees. They also work well in practice, correctly ordering mean by "preserving visual properties" via an example. Consider the following query on a database

  12. Pedophilia, Sexual Orientation, and Birth Order

    Microsoft Academic Search

    Anthony F. Bogaert; Scott Bezeau; Michael Kuban; Ray Blanchard

    1997-01-01

    This study extended research on birth order and erotic preferences by examining birth order in a sample of pedophiles. Charts of 338 pedophiles, assessed from 1980–1994 in the Behavioural Sexology Department of the Clarke Institute of Psychiatry in Toronto, were reviewed for family–demographic information. In total, 170 (57 heterosexual pedophiles, 68 homosexual pedophiles, and 45 bisexual pedophiles) of these men

  13. Review essay \\/ What kind of order?

    Microsoft Academic Search

    Robert Jackall

    2003-01-01

    Bernard E. Harcourt, Illusion of Order: The False Promise of Broken Windows Policing Cambridge, MA: Harvard University Press, 2001, x + 294 pp.David Garland, The Culture of Control: Crime and Social Order in Contemporary Society Chicago: University of Chicago Press, 2001, xiii + 307 pp.Andrea McArdle and Tanya Erzen (eds.), Zero Tolerance: Quality of Life and the New Police Brutality

  14. Order statistics from the half logistic distribution

    Microsoft Academic Search

    N. Balakrishnan

    1985-01-01

    Let X be a random variable having a half logistic distribution, obtained by folding the logistic distribution. For this distribution, some recurrence relations are established for the moments and product moments of order statistics. Starting with the first k moments of X, it is noted that one can calculate the first k moments of all order statistics. Using these relations,

  15. Order-invariant measures on causal sets

    Microsoft Academic Search

    Graham Brightwell; Malwina Luczak

    2009-01-01

    A causal set is a partially ordered set on a countably infinite ground-set such that each element is above finitely many others. A natural extension of a causal set is an enumeration of its elements which respects the order. We bring together two different classes of random processes. In one class, we are given a fixed causal set, and we

  16. Tableau Calculus for Order Sorted Logic

    Microsoft Academic Search

    Peter H. Schmitt; Wolfgang Wernecke

    1989-01-01

    In this paper we discuss a calculus for order sorted logic, based on an extension of the tableau method. We first present the background of our investigation by specifying the underlying representation language and its interpretation. Then we introduce the tableau calculus for order sorted logic and show the completeness of the method. Finally we discuss some issues related to

  17. Predicting Partial Orders: Ranking with Abstention

    E-print Network

    Hüllermeier, Eyke

    Predicting Partial Orders: Ranking with Abstention Weiwei Cheng1 , Micha¨el Rademaker2 , Bernard De Control Ghent University, Belgium {michael.rademaker,bernard.debaets}@ugent.be Abstract. The prediction predictions in the form of partial instead of total orders. We interpret such kind of prediction as a ranking

  18. Order statistics in digital image processing

    Microsoft Academic Search

    IOANNIS PITAS; ANASTASIOS N. VENETSANOPOULOS

    1992-01-01

    A family of nonlinear filters based on order statistics is presented. A mathematical tool derived through robust estimation theory, order statistics has allowed engineers to develop nonlinear filters with excellent robustness properties. These filters are well suited to digital image processing because they preserve the edges and the fine details of an image much better than conventional linear filters. The

  19. Second-order statistics of complex signals

    Microsoft Academic Search

    Bernard Picinbono; Pascal Bondon

    1997-01-01

    The second-order statistical properties of complex signals are usually characterized by the covariance function. However, this is not sufficient for a complete second-order description, and it is necessary to introduce another moment called the relation function. Its properties, and especially the conditions that it must satisfy, are analyzed both for stationary and nonstationary signals. This leads to a new perspective

  20. Decomposing liquidity along the limit order book

    Microsoft Academic Search

    David Rakowski; Xiaoxin Wang Beardsley

    2008-01-01

    In this paper, we estimate the asymmetric information and order processing components of liquidity at extended depths along the limit order book. Using data from the INET ECN, we find that the asymmetric information component decreases as depth increases. Inactive stocks have more information asymmetry at the inside quotes, but it decreases more rapidly along the book than for active

  1. Basic Supply Order Job Aid For Preparers

    E-print Network

    Wildermuth, Mary C

    , such as split funding the order. Note: If you are split funding an order, note project name or fund number supplies are benefiting and dollar amount or percentage of split in the comments section. 10. Complete. Faculty name (approver) should pre-populate above the password box, once you set your password. Type

  2. Retrieval Strategies for Linearly Ordered Information

    ERIC Educational Resources Information Center

    Polich, John M.; Potts, George R.

    1977-01-01

    Subjects responded to pairs of test items from learned linear orderings (e.g., Tom is taller than Dick; Dick is taller than Sam, etc.). Results are compared with previous studies of ordered linguistic, perceptual, and numerical information. (Editor/RK)

  3. Duplicate Diploma Order Office of the Registrar

    E-print Network

    de Doncker, Elise

    as the diploma you were awarded when you graduated. Mail to: Name on diploma: Name at graduation: SSN or WIN: Discover MasterCard Visa Check Money Order Card Number Expire Date: Security Code: Amount $ Name on Card shipping, please include an additional $55 - Make check or money orders payable to Western Michigan

  4. Hadronic quarkonium decays at order v7

    NASA Astrophysics Data System (ADS)

    Brambilla, Nora; Vairo, Antonio; Mereghetti, Emanuele

    2009-04-01

    We compute the complete imaginary part of the nonrelativistic QCD (NRQCD) Lagrangian at order 1/M4 in the heavy-quark mass expansion, which includes center of mass operators, and at order ?s2 in the matching coefficients. We also compute the imaginary part of the NRQCD Lagrangian at order 1/M6 and at order ?s2 that contributes to the S-wave and P-wave inclusive decay widths of heavy quarkonium into light hadrons at order v7 in the heavy-quark velocity expansion. If we count ?s(M)˜v2, the calculation provides the complete next-to-leading order corrections to the P-wave hadronic widths, and in the original NRQCD power counting, the complete next-to-leading order corrections to the vector S-wave widths, and part of the next-to-next-to leading order corrections to the pseudoscalar S-wave widths. In the S-wave case, we confirm previous findings and add new terms in a more conservative power counting. In the P-wave case, our results are in disagreement with previous ones. Constraints induced by Poincaré invariance on the NRQCD four-fermion sector are studied for the first time and provide an additional check of the calculation. Perspectives for phenomenological applications are discussed.

  5. Higher Order Thinking in the Dance Studio

    Microsoft Academic Search

    Ann-Thomas Moffett

    2012-01-01

    The author identifies higher order thinking as an essential component of dance training for students of all ages and abilities. Weaving together insights from interviews with experts in the field of dance education with practical pedagogical applications within an Improvisation and Composition class for talented and gifted youth, this article reveals the author's uncovering understanding of higher order thinking. Emphasis

  6. Protein Remote Homology Detection Using Order Profiles

    Microsoft Academic Search

    Bin Liu; Lei Lin; Xiaolong Wang; Xuan Wang

    2009-01-01

    Protein remote homology detection is a central problem in bioinformatics. In this study, we present a novel building block of proteins called order profiles (OP) to use the evolutionary information of the protein sequence frequency profiles and apply this novel building block to remote homology detection. Order profiles contain the evolutionary information extracted from the protein sequence frequency profiles outputted

  7. Time and Order Effects on Causal Learning

    ERIC Educational Resources Information Center

    Alvarado, Angelica; Jara, Elvia; Vila, Javier; Rosas, Juan M.

    2006-01-01

    Five experiments were conducted to explore trial order and retention interval effects upon causal predictive judgments. Experiment 1 found that participants show a strong effect of trial order when a stimulus was sequentially paired with two different outcomes compared to a condition where both outcomes were presented intermixed. Experiment 2…

  8. Chemical Dosing and First-Order Kinetics

    ERIC Educational Resources Information Center

    Hladky, Paul W.

    2011-01-01

    College students encounter a variety of first-order phenomena in their mathematics and science courses. Introductory chemistry textbooks that discuss first-order processes, usually in conjunction with chemical kinetics or radioactive decay, stop at single, discrete dose events. Although single-dose situations are important, multiple-dose events,…

  9. Axiomatizing first order consequences in dependence logic

    E-print Network

    Väänänen, Jouko

    Axiomatizing first order consequences in dependence logic Juha Kontinen Jouko V¨a¨an¨anen May 18, 2012 Abstract Dependence logic, introduced in [8], cannot be axiomatized. However, first-order consequences of dependence logic sentences can be axiomatized, and this is what we shall do in this paper. We

  10. Invariant Ordering of Item-Total Regressions

    ERIC Educational Resources Information Center

    Tijmstra, Jesper; Hessen, David J.; van der Heijden, Peter G. M.; Sijtsma, Klaas

    2011-01-01

    A new observable consequence of the property of invariant item ordering is presented, which holds under Mokken's double monotonicity model for dichotomous data. The observable consequence is an invariant ordering of the item-total regressions. Kendall's measure of concordance "W" and a weighted version of this measure are proposed as measures for…

  11. Toward Optimal Ordering of Prediction Tasks

    Microsoft Academic Search

    Abhimanyu Lad; Yiming Yang; Rayid Ghani; Bryan Kisiel

    2009-01-01

    Many applications involve a set of prediction tasks that must be accomplished sequentially through user interaction. If the tasks are interdependent, the order in which they are performed may have a signicant impact on the overall per- formance of the prediction systems. However, manual speci- cation of an optimal order may be dicult when the inter- dependencies are complex, especially

  12. Higher-Order Neural Networks Recognize Patterns

    NASA Technical Reports Server (NTRS)

    Reid, Max B.; Spirkovska, Lilly; Ochoa, Ellen

    1996-01-01

    Networks of higher order have enhanced capabilities to distinguish between different two-dimensional patterns and to recognize those patterns. Also enhanced capabilities to "learn" patterns to be recognized: "trained" with far fewer examples and, therefore, in less time than necessary to train comparable first-order neural networks.

  13. Intelligence, birth order, and family size.

    PubMed

    Kanazawa, Satoshi

    2012-09-01

    The analysis of the National Child Development Study in the United Kingdom (n = 17,419) replicates some earlier findings and shows that genuine within-family data are not necessary to make the apparent birth-order effect on intelligence disappear. Birth order is not associated with intelligence in between-family data once the number of siblings is statistically controlled. The analyses support the admixture hypothesis, which avers that the apparent birth-order effect on intelligence is an artifact of family size, and cast doubt on the confluence and resource dilution models, both of which claim that birth order has a causal influence on children's cognitive development. The analyses suggest that birth order has no genuine causal effect on general intelligence. PMID:22581677

  14. Constraints on topological order in mott insulators.

    PubMed

    Zaletel, Michael P; Vishwanath, Ashvin

    2015-02-20

    We point out certain symmetry induced constraints on topological order in Mott insulators (quantum magnets with an odd number of spin 1/2 moments per unit cell). We show, for example, that the double-semion topological order is incompatible with time reversal and translation symmetry in Mott insulators. This sharpens the Hastings-Oshikawa-Lieb-Schultz-Mattis theorem for 2D quantum magnets, which guarantees that a fully symmetric gapped Mott insulator must be topologically ordered, but is silent about which topological order is permitted. Our result applies to the kagome lattice quantum antiferromagnet, where recent numerical calculations of the entanglement entropy indicate a ground state compatible with either toric code or double-semion topological order. Our result rules out the latter possibility. PMID:25763971

  15. Constraints on topological order in Mott Insulators

    E-print Network

    Michael P. Zaletel; Ashvin Vishwanath

    2015-04-18

    We point out certain symmetry induced constraints on topological order in Mott Insulators (quantum magnets with an odd number of spin $\\tfrac{1}{2}$ per unit cell). We show, for example, that the double semion topological order is incompatible with time reversal and translation symmetry in Mott insulators. This sharpens the Hastings-Oshikawa-Lieb-Schultz-Mattis theorem for 2D quantum magnets, which guarantees that a fully symmetric gapped Mott insulator must be topologically ordered, but is silent on which topological order is permitted. An application of our result is the Kagome lattice quantum antiferromagnet where recent numerical calculations of entanglement entropy indicate a ground state compatible with either toric code or double semion topological order. Our result rules out the latter possibility.

  16. Arbitrary order permanent Cartesian multipolar electrostatic interactions.

    PubMed

    Boateng, H A; Todorov, I T

    2015-01-21

    Recently, there has been a concerted effort to implement advanced classical potential energy surfaces by adding higher order multipoles to fixed point charge electrostatics in a bid to increase the accuracy of simulations of condensed phase systems. One major hurdle is the unwieldy nature of the expressions which in part has limited developers mostly to including only dipoles and quadrupoles. In this paper, we present a generalization of the Cartesian formulation of electrostatic multipolar interactions that enables the specification of an arbitrary order of multipoles. Specifically, we derive formulas for arbitrary order implementation of the particle mesh Ewald method and give a closed form formula for the stress tensor in the reciprocal space. In addition, we provide recurrence relations for common electrostatic potentials employed in molecular simulations, which allows for the generalization to arbitrary order and guarantees a computational cost that scales as O(p(3)) for Cartesian multipole interactions of order p. PMID:25612699

  17. Local orientational order in the Stockmayer liquid

    E-print Network

    Veniamin Blinov

    2012-06-21

    Phase behaviour of the Stockmayer fluid is studied with a method similar to the Monte-Carlo annealing scheme. We introduce a novel order parameter which is sensitive to the local co-orientation of the dipoles of particles in the fluid. We exhibit a phase diagram based on the behaviour of the order parameter in the density region 0.1 \\leq {\\rho}\\ast \\leq 0.32. Specifically, we observe and analyse a second order locally disordered fluid \\rightarrow locally oriented fluid phase transition.

  18. Topological order following a quantum quench

    SciTech Connect

    Tsomokos, Dimitris I. [School of Physics and Astronomy, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa (Italy); Department of Mathematics, Royal Holloway, University of London, Egham TW20 0EX (United Kingdom); Hamma, Alioscia [Perimeter Institute for Theoretical Physics, 31 Caroline Street N, Waterloo, Ontario, Canada N2L 2Y5 (Canada); Zhang Wen; Haas, Stephan [Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089 (United States); Fazio, Rosario [Scuola Normale Superiore, Piazza dei Cavalieri 7, 56126 Pisa (Italy); Center for Quantum Technologies, National University of Singapore, Singapore (Singapore)

    2009-12-15

    We determine the conditions under which topological order survives a rapid quantum quench. Specifically, we consider the case where a quantum spin system is prepared in the ground state of the toric code model and, after the quench, it evolves with a Hamiltonian that does not support topological order. We provide analytical results supported by numerical evidence for a variety of quench Hamiltonians. The robustness of topological order under nonequilibrium situations is tested by studying the topological entropy and a dynamical measure, which makes use of the similarity between partial density matrices obtained from different topological sectors.

  19. Roughness in lattice ordered effect algebras.

    PubMed

    Xin, Xiao Long; Hua, Xiu Juan; Zhu, Xi

    2014-01-01

    Many authors have studied roughness on various algebraic systems. In this paper, we consider a lattice ordered effect algebra and discuss its roughness in this context. Moreover, we introduce the notions of the interior and the closure of a subset and give some of their properties in effect algebras. Finally, we use a Riesz ideal induced congruence and define a function e(a, b) in a lattice ordered effect algebra E and build a relationship between it and congruence classes. Then we study some properties about approximation of lattice ordered effect algebras. PMID:25170523

  20. Numerical calculation of second order perturbations

    SciTech Connect

    Huston, Ian; Malik, Karim A., E-mail: i.huston@qmul.ac.uk, E-mail: k.malik@qmul.ac.uk [Astronomy Unit, School of Mathematical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS (United Kingdom)

    2009-09-01

    We numerically solve the Klein-Gordon equation at second order in cosmological perturbation theory in closed form for a single scalar field, describing the method employed in detail. We use the slow-roll version of the second order source term and argue that our method is extendable to the full equation. We consider two standard single field models and find that the results agree with previous calculations using analytic methods, where comparison is possible. Our procedure allows the evolution of second order perturbations in general and the calculation of the non-linearity parameter f{sub NL} to be examined in cases where there is no analytical solution available.

  1. Thermal Conductivity of Ordered Molecular Water

    SciTech Connect

    W Evans; J Fish; P Keblinski

    2006-02-16

    We use molecular dynamics simulation to investigate thermal transport characteristics of water with various degree of orientational and translational order induced by the application of an electric field. We observe that orientational ordering of the water dipole moments has a minor effect on the thermal conductivity. However, electric-field induced crystallization and associated translational order results in approximately a 3-fold increase of thermal conductivity with respect to the base water, i.e., to values comparable with those characterizing ice crystal structures.

  2. Thermal conductivity of ordered molecular water.

    PubMed

    Evans, William; Fish, Jacob; Keblinski, Pawel

    2007-04-21

    The authors use molecular dynamics simulation to investigate the thermal transport characteristics of water with various degree of orientational and translational orders induced by the application of an electric field. The authors observe that the orientational ordering of the water dipole moments has a minor effect on the thermal conductivity. However, electric-field-induced crystallization and associated translational order result in approximately a three fold increase of thermal conductivity with respect to the base water, i.e., to values comparable with those characterizing ice crystal structures. PMID:17461644

  3. 78 FR 46823 - Kiwifruit Grown in California; Proposed Amendments to Marketing Order 920 and Referendum Order

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-08-02

    ...DEPARTMENT OF AGRICULTURE Agricultural Marketing Service 7 CFR Part 920 [Doc. No. AMS-FV-12-0008...in California; Proposed Amendments to Marketing Order 920 and Referendum Order AGENCY: Agricultural Marketing Service, USDA. ACTION: Proposed...

  4. 75 FR 21157 - Milk in the Northeast and Other Marketing Areas; Order Amending the Orders

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-23

    ...DEPARTMENT OF AGRICULTURE Agricultural Marketing Service 7 CFR Parts 1001, 1005, 1006...DA-09-02] Milk in the Northeast and Other Marketing Areas; Order Amending the Orders AGENCY: Agricultural Marketing Service, USDA ACTION: Final...

  5. 77 FR 51693 - Milk in the Mideast Marketing Area; Order Amending the Order

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-08-27

    ...DEPARTMENT OF AGRICULTURE Agricultural Marketing Service 7 CFR Part 1033 [Doc. No...DA-11-04] Milk in the Mideast Marketing Area; Order Amending the Order AGENCY: Agricultural Marketing Service, USDA. ACTION: Final...

  6. 78 FR 24334 - Milk in the Northeast and Other Marketing Areas; Order Amending the Orders

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-25

    ...DEPARTMENT OF AGRICULTURE Agricultural Marketing Service 7 CFR Part 1000 [Doc. no...DA-07-02] Milk in the Northeast and Other Marketing Areas; Order Amending the Orders AGENCY: Agricultural Marketing Service, USDA. ACTION: Final...

  7. 76 FR 4201 - Kiwifruit Grown in California; Order Amending Marketing Order No. 920; Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-25

    ...DEPARTMENT OF AGRICULTURE Agricultural Marketing Service 7 CFR Part 920 [Doc. No. AO-FV-08-0174...Grown in California; Order Amending Marketing Order No. 920; Correction AGENCY: Agricultural Marketing Service, USDA. ACTION:...

  8. 75 FR 37288 - Kiwifruit Grown in California; Order Amending Marketing Order No. 920

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-29

    ...DEPARTMENT OF AGRICULTURE Agricultural Marketing Service 7 CFR Part 920 [Doc. No. AO-FV-08-0174...Kiwifruit Grown in California; Order Amending Marketing Order No. 920 AGENCY: Agricultural Marketing Service, USDA. ACTION: Final...

  9. 75 FR 51929 - Milk in the Northeast and Other Marketing Areas; Order Amending the Orders

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-24

    ...DEPARTMENT OF AGRICULTURE Agricultural Marketing Service 7 CFR Part 1000 [Doc. No...DA-03-10] Milk in the Northeast and Other Marketing Areas; Order Amending the Orders AGENCY: Agricultural Marketing Service, USDA. ACTION: Final...

  10. 10 CFR 490.602 - Special orders.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...2011-01-01 2011-01-01 false Special orders. 490.602 Section 490.602 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ALTERNATIVE FUEL TRANSPORTATION PROGRAM Investigations and Enforcement § 490.602 Special...

  11. 10 CFR 490.602 - Special orders.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...2014-01-01 2014-01-01 false Special orders. 490.602 Section 490.602 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ALTERNATIVE FUEL TRANSPORTATION PROGRAM Investigations and Enforcement § 490.602 Special...

  12. 78 FR 58995 - Order Denying Export Privileges

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-09-25

    ...Denying Export Privileges In the Matter of: Iman Kazerani, 153 Orient Way, Rutherford...District Court, District of New Jersey, Iman Kazerani (``Kazerani'') was convicted...hereby Ordered I. Until January 30, 2018, Iman Kazerani, with a last known address...

  13. 21 CFR 1303.37 - Final order.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ...the record to the Administrator, the Administrator shall issue his order on the determination or adjustment of the aggregate production quota or on the issuance, adjustment, suspension, or denial of the procurement quota or individual...

  14. Higher-order force gradient symplectic algorithms

    PubMed

    Chin; Kidwell

    2000-12-01

    We show that a recently discovered fourth order symplectic algorithm, which requires one evaluation of force gradient in addition to three evaluations of the force, when iterated to higher order, yielded algorithms that are far superior to similarly iterated higher order algorithms based on the standard Forest-Ruth algorithm. We gauge the accuracy of each algorithm by comparing the step-size independent error functions associated with energy conservation and the rotation of the Laplace-Runge-Lenz vector when solving a highly eccentric Kepler problem. For orders 6, 8, 10, and 12, the new algorithms are approximately a factor of 10(3), 10(4), 10(4), and 10(5) better. PMID:11138177

  15. Noncommutative ordered spaces: examples and counterexamples

    NASA Astrophysics Data System (ADS)

    Besnard, Fabien

    2015-07-01

    In order to introduce the notion of causality in noncommutative geometry, it is necessary to extend Gelfand theory to the context of ordered spaces. In a previous work we have already given an algebraic characterization of the set of non-decreasing continuous functions on a certain class of topological ordered spaces. Such a set is called an isocone, and there exist at least two versions of them (strong and weak) which coincide in the commutative case. In this paper, we introduce yet another breed of isocones, ultraweak isocones, which has a simpler definition with a clear physical meaning. We show that ultraweak and weak isocones are in fact the same, and completely classify those that live in a finite-dimensional {C}*-algebra, hence corresponding to finite noncommutative ordered spaces. We also give some examples in infinite dimension.

  16. 10 CFR 490.602 - Special orders.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...2010-01-01 2010-01-01 false Special orders. 490.602 Section 490.602 Energy DEPARTMENT OF ENERGY ENERGY CONSERVATION ALTERNATIVE FUEL TRANSPORTATION PROGRAM Investigations and Enforcement § 490.602 Special...

  17. 48 CFR 2417.504 - Ordering procedures.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...Federal Acquisition Regulations System DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT CONTRACTING METHODS AND CONTRACTING TYPES SPECIAL CONTRACTING METHODS Interagency Acquisitions Under the Economy Act 2417.504 Ordering procedures. (b) The...

  18. 48 CFR 2417.504 - Ordering procedures.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...Federal Acquisition Regulations System DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT CONTRACTING METHODS AND CONTRACTING TYPES SPECIAL CONTRACTING METHODS Interagency Acquisitions Under the Economy Act 2417.504 Ordering procedures. (b) The...

  19. 48 CFR 2417.504 - Ordering procedures.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...Federal Acquisition Regulations System DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT CONTRACTING METHODS AND CONTRACTING TYPES SPECIAL CONTRACTING METHODS Interagency Acquisitions Under the Economy Act 2417.504 Ordering procedures. (b) The...

  20. 48 CFR 2417.504 - Ordering procedures.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...Federal Acquisition Regulations System DEPARTMENT OF HOUSING AND URBAN DEVELOPMENT CONTRACTING METHODS AND CONTRACTING TYPES SPECIAL CONTRACTING METHODS Interagency Acquisitions Under the Economy Act 2417.504 Ordering procedures. (b) The...