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1

Magnetic field induced order in quasi-one-dimensional systems  

NASA Astrophysics Data System (ADS)

We investigate possible ordered phases in a magnetic field in quasi-one-dimensional conductors (Q1D). Long ago [I.E. Dzyaloshinskii, E.I. Kats, JETP 28 (1969) 178] we found that sufficiently strong external magnetic field leads to instability of the Fermi state with an arbitrarily weak repulsion between the particles. In the present communication we generalize this idea and provide more details to assign a physical meaning to such a state. We show that without umklapp processes the found instability corresponds to antiferromagnetic (spin density wave) order, whereas umklapp processes favor to Cooper pairing.

Dzyaloshinskii, I. E.; Kats, E. I.

2012-06-01

2

Magnetic-field-induced orientational order in the isotropic phase of hard colloidal platelets  

SciTech Connect

The magnetic-field-induced orientational order in the isotropic phase of colloidal gibbsite [Al(OH){sub 3}] platelets is studied by means of optical birefringence and small-angle x-ray scattering (SAXS) techniques. The suspensions display field-induced ordering at moderate field strengths (a few Tesla), which increases with increasing particle concentration. The gibbsite particles align their normals perpendicular to the magnetic field and hence possess a negative anisotropy of their diamagnetic susceptibility {delta}{chi}. The results can be described following a simple, Onsager-like approach. A simplified model is derived that allows one to obtain the orientational distribution function directly from the scattering data. However, it leads to an underestimate of the diamagnetic susceptibility anisotropy {delta}{chi}. This accounts for the difference between the {delta}{chi} values provided by the two experimental techniques (SAXS and magneto-optics). The order of magnitude {delta}{chi}{approx}10{sup -22} J/T{sup 2} lies in between that of goethite suspensions and that of suspensions of organic particles.

Beek, D. van der; Petukhov, A.V.; Vroege, G.J.; Lekkerkerker, H.N.W. [Van't Hoff Laboratory for Physical and Colloid Chemistry, Debye Institute, Utrecht University, Padualaan 8, 3584 CH Utrecht (Netherlands); Davidson, P.; Ferre, J.; Jamet, J.P. [Laboratoire de Physique des Solides, UMR 8502 CNRS, Universite Paris-Sud, Batiment 510, 91405 Orsay (France); Wensink, H.H. [Institut fuer Theoretische Physik II, Heinrich-Heine-Universitaet Duesseldorf, Universitaetsstrasse 1, Gebaeude 25.32, 40225 Duesseldorf (Germany); Bras, W. [Netherlands Organisation for Scientific Research (NWO), DUBBLE CRG, European Synchrotron Radiation Facility, BP 220, 38043 Grenoble Cedex (France)

2006-04-15

3

Magnetic-field-induced orientational order in the isotropic phase of hard colloidal platelets.  

PubMed

The magnetic-field-induced orientational order in the isotropic phase of colloidal gibbsite [Al(OH)3] platelets is studied by means of optical birefringence and small-angle x-ray scattering (SAXS) techniques. The suspensions display field-induced ordering at moderate field strengths (a few Tesla), which increases with increasing particle concentration. The gibbsite particles align their normals perpendicular to the magnetic field and hence possess a negative anisotropy of their diamagnetic susceptibility Delta(chi). The results can be described following a simple, Onsager-like approach. A simplified model is derived that allows one to obtain the orientational distribution function directly from the scattering data. However, it leads to an underestimate of the diamagnetic susceptibility anisotropy Delta(chi). This accounts for the difference between the Delta(chi) values provided by the two experimental techniques (SAXS and magneto-optics). The order of magnitude Delta(chi) approximately 10(-22) J/T(2) lies in between that of goethite suspensions and that of suspensions of organic particles. PMID:16711795

van der Beek, D; Petukhov, A V; Davidson, P; Ferré, J; Jamet, J P; Wensink, H H; Vroege, G J; Bras, W; Lekkerkerker, H N W

2006-04-05

4

Magnetic field-induced ordering of a polymer-grafted biomembrane-mimetic hydrogel  

SciTech Connect

A biomembrane-mimetic complex fluid that spontaneously orients in the presence of a magnetic field to yield a highly ordered lamellar structure is described. Macroscopically oriented lamellae were produced by exploiting the inverted thermoreversible phase transition of the material, that is, by aligning the sample below the phase transition temperature (<16 C)(i.e., in the fluid, hexagonal micellar phase) and warming to produce the lamellar gel phase in a 7.05 T magnetic field. The in situ field-induced alignment was studied by deuterium NMR. The lamellar domains were found to preferentially orient perpendicular to the applied field (negative order). Characterization of the magnetic field-induced anisotropy by polarized optical microscopy and small-angle X-ray scattering/diffraction (SAXS) indicates that it persists even upon field termination. The directional alignment was flipped by 90{degree}, with the lamellar domains oriented parallel to the field (positive order), simply by modifying the composition through the addition of a lanthanide ion (EU{sup 3+}). The system offers the opportunity to spatially organize both membrane and aqueous soluble proteins in an anisotropic matrix, thereby facilitating structure and dynamic studies using a range of techniques, including magnetic resonance (both NMR as well as EPR), optical spectroscopy, and small-angle neutron and X-ray scattering.

Firestone, M.A.; Tiede, D.M.; Seifert, S.

2000-03-23

5

Magnetic field-induced ordering in SrDy2O4  

NASA Astrophysics Data System (ADS)

Heat capacity measurements were used to investigate the magnetic ordering processes in single-crystal samples of SrDy2O4 in a magnetic field applied along the [010] and [001] directions. In zero field this compound appears to be magnetically disordered down to at least 0.39 K. A magnetic field applied along the [010] direction induces a very sharp transition at 20 kOe, seen as a strong peak in the heat capacity versus field, C(H) curves, while for H ? [001], the magnetization process is accompanied by the development of only broad features in the C(H) curves. The process of field-induced ordering in SrDy2O4 appears to be rather remarkable even in the context of the unusual phase transitions observed in other geometrically frustrated magnetic systems consisting of hexagons and triangles.

Cheffings, T. H.; Lees, M. R.; Balakrishnan, G.; Petrenko, O. A.

2013-06-01

6

Antiferroquadrupolar ordering and magnetic-field-induced phase transition in the cage compound PrRh2Zn20  

NASA Astrophysics Data System (ADS)

To investigate the origin of a phase transition at TQ=0.06 K simultaneously occurring with a superconducting transition in a cage compound PrRh2Zn20, we carried out ultrasonic measurements on a single-crystalline sample. The transverse modulus (C11-C12)/2 is intimately coupled to the non-Kramers ground doublet ?3, and elastic softening is observed at low temperatures. Below TQ, the softening stops, suggesting the disappearance of quadrupole degrees of freedom. We clarified the negative quadrupole-quadrupole coupling constant and reentrant behavior of TQ(H) in a magnetic field H. These results reveal that the phase transition at TQ is antiferroquadrupolar ordering. The anisotropic magnetic field-temperature phase diagram is determined for H?[100], [110], and [111]. A magnetic-field-induced phase transition is newly found at high fields in all three field directions. We also observed ultrasonic dispersion at around 50 K owing to the rattling motion of Zn atoms at the 16c site, and pointed out the strong electron-phonon coupling in PrRh2Zn20.

Ishii, Isao; Muneshige, Hitoshi; Kamikawa, Shuhei; Fujita, Takahiro K.; Onimaru, Takahiro; Nagasawa, Naohiro; Takabatake, Toshiro; Suzuki, Takashi; Ano, Genki; Akatsu, Mitsuhiro; Nemoto, Yuichi; Goto, Terutaka

2013-05-01

7

Magnetic Field Induced Transitions from Spin Glass to Liquid to Long Range Order in a 3D Geometrically Frustrated Magnet  

Microsoft Academic Search

Gadolinium gallium garnet, Gd3Ga5O12, has an extraordinary low temperature phase diagram including a spin glass phase near H = 0 T, an antiferromagnetic (AFM) phase for 0.7<=H<=1.4 T, and, at intermediate fields, an apparent spin-liquid state without long range order. We have characterized the intermediate field (IF) state through heat capacity, thermal conductivity, and magnetocaloric measurements. Our results indicate that

Y. K. Tsui; C. A. Burns; J. Snyder; P. Schiffer

1999-01-01

8

Shear- and magnetic-field-induced ordering in magnetic nanoparticle dispersion from small-angle neutron scattering.  

PubMed

Small-angle neutron scattering experiments have been performed to investigate orientational ordering of a dispersion of rod-shaped ferromagnetic nanoparticles under the influence of shear flow and static magnetic field. In this experiment, the flow and flow gradient directions are perpendicular to the direction of the applied magnetic field. The scattering intensity is isotropic in zero-shear-rate or zero-applied-field conditions, indicating that the particles are randomly oriented. Anisotropic scattering is observed both in a shear flow and in a static magnetic field, showing that both flow and field induce orientational order in the dispersion. The anisotropy increases with the increase of field and with the increase of shear rate. Three states of order have been observed with the application of both shear flow and magnetic field. At low shear rates, the particles are aligned in the field direction. When increasing shear rate is applied, the particles revert to random orientations at a characteristic shear rate that depends on the strength of the applied magnetic field. Above the characteristic shear rate, the particles align along the flow direction. The experimental results agree qualitatively with the predictions of a mean field model. PMID:12786151

Krishnamurthy, V V; Bhandar, A S; Piao, M; Zoto, I; Lane, A M; Nikles, D E; Wiest, J M; Mankey, G J; Porcar, L; Glinka, C J

2003-05-23

9

Magnetic-field-induced phase transition in BiFeO3 observed by high-field electron spin resonance: Cycloidal to homogeneous spin order  

Microsoft Academic Search

Bismuth ferrite is a magnetoelectric material, which simultaneously has polarization and spin orders. We have used electron spin resonance (ESR) as a local probe of the magnetic order in the magnetic-field range of 0 25 T, in the frequency domain of 115 360 GHz, and at a temperature of 4.2 K. The data reveal significant changes in the ESR spectra

Benjamin Ruette; S. Zvyagin; A. P. Pyatakov; A. Bush; J. F. Li; V. I. Belotelov; A. K. Zvezdin; D. Viehland

2004-01-01

10

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

NASA Astrophysics Data System (ADS)

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.

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

2011-11-01

11

TmCd quadrupolar ordering and magnetic interactions  

Microsoft Academic Search

The paramagnetic compound TmCd crystallizes with the CsCl-type structure. Its Jahn-Teller behavior was first observed by Lüthi and coworkers. We analyze here various physical properties with a pure-harmonic-elasticity model. The structural transition between cubic and tetragonal phases is now fully described (first-order character and temperature of occurrence) as well as the magnetic susceptibility, magnetization process, specific-heat, elastic-constant, and strain data.

R. Aléonard; P. Morin

1979-01-01

12

X-Ray Resonant Scattering Study of the Quadrupolar Order in UPd3  

NASA Astrophysics Data System (ADS)

Quadrupolar ordering in a 5f electron system has been observed directly for the first time, using x-ray scattering techniques. In UPd 3 at low temperatures satellite peaks appear at (1,0,l) (orthorhombic notation) with l odd and even. Both sets of peaks show a resonant enhancement of the scattering at the MIV edge of U. At resonance, the dominant scattering of the l odd peaks occurs in the unrotated polarization channel, whereas for l even a significant rotated component is found. These results are discussed in terms of possible structures of the antiferroquadrupolar phases.

McMorrow, D. F.; McEwen, K. A.; Steigenberger, U.; Rønnow, H. M.; Yakhou, F.

2001-07-01

13

Magnetic-field-induced shape recovery by reverse phase transformation  

NASA Astrophysics Data System (ADS)

Large magnetic-field-induced strains have been observed in Heusler alloys with a body-centred cubic ordered structure and have been explained by the rearrangement of martensite structural variants due to an external magnetic field. These materials have attracted considerable attention as potential magnetic actuator materials. Here we report the magnetic-field-induced shape recovery of a compressively deformed NiCoMnIn alloy. Stresses of over 100MPa are generated in the material on the application of a magnetic field of 70kOe such stress levels are approximately 50 times larger than that generated in a previous ferromagnetic shape-memory alloy. We observed 3 per cent deformation and almost full recovery of the original shape of the alloy. We attribute this deformation behaviour to a reverse transformation from the antiferromagnetic (or paramagnetic) martensitic to the ferromagnetic parent phase at 298K in the Ni45Co5Mn36.7In13.3 single crystal.

Kainuma, R.; Imano, Y.; Ito, W.; Sutou, Y.; Morito, H.; Okamoto, S.; Kitakami, O.; Oikawa, K.; Fujita, A.; Kanomata, T.; Ishida, K.

2006-02-01

14

Muon spin relaxation and neutron diffraction investigations of quadrupolar and magnetically ordered states of YbRu2Ge2  

NASA Astrophysics Data System (ADS)

The magnetic- and quadrupolar-ordered states of polycrystalline YbRu2Ge2 have been investigated using zero-field (ZF) muon spin relaxation (?SR) and neutron diffraction measurements. Specific heat measurements show three successive phase transitions with decreasing temperature from a paramagnetic to a quadrupolar state at T0 ˜ 10 K, from the quadrupolar to a magnetic state at T1 ˜ 6.5 K, and a possible change in the magnetic ground state at T2 ˜ 5.5 K. Clear evidence for the magnetic transition below 7 K (spectrum at 8 K reveals paramagnetic state) and a likely change in the magnetic structure near 5.8 K is observed in the ZF ?SR measurements. The ?SR data, however, do not reveal any signature of magnetic order in the temperature range 8-45 K. This result is further supported by neutron-diffraction measurements, where clear magnetic Bragg peaks have been observed below 8 K, but not above it. Below 8 K, the magnetic Bragg peaks can be characterized by an incommensurate antiferromagnetic (AF) ordering with the propagation vector q = [0.352, 0, 0] and the magnetic moment 2.9(3) ?B of Yb along the b-axis. These results are discussed in terms of quadrupolar-ordered and magnetically ordered states.

Jeevan, H. S.; Adroja, D. T.; Hillier, A. D.; Hossain, Z.; Ritter, C.; Geibel, C.

2011-11-01

15

Magnetic-Field-Induced Electric Polarization in Multiferroic Nanostructures  

NASA Astrophysics Data System (ADS)

Magnetic-field-induced electric polarization in nanostructured multiferroic composite films was studied by using the Green’s function approach. The calculations showed that large magnetic-field-induced polarization could be produced in multiferroic nanostructures due to enhanced elastic coupling interaction. Especially, the 1-3 type films with ferromagnetic nanopillars embedded in a ferroelectric matrix exhibited large magnetic-field-induced polarization responses, while the 2-2 type films with ferroelectric and ferromagnetic nanolaminates showed much weaker magnetoelectric coupling and lower magnetic induced polarization due to large in-plane constraint effect, which was in agreement with the recent observations.

Nan, Ce-Wen; Liu, Gang; Lin, Yuanhua; Chen, Haydn

2005-05-01

16

Magnetic-Field Induced Second Harmonic Generation in CuB2O4  

NASA Astrophysics Data System (ADS)

Three types of optical magnetic-field induced second harmonic (MFISH) generation are observed in CuB2O4. Unusually sharp and intense electronic transitions in MFISH and linear absorption spectra provide selective access to the two nonequivalent Cu2+ sublattices. The magnetic phase diagram for both sublattices is determined by MFISH. Magnetic structure is dominated by antiferromagnetic order at the 4b site. Sublattice interactions transfer it to the 8d site where it coexists with a discoupled paramagnetic component.

Pisarev, R. V.; Sänger, I.; Petrakovskii, G. A.; Fiebig, M.

2004-07-01

17

Microscopic theory of magnetic-field-induced structural phase transitions  

Microsoft Academic Search

The microscopic theory of a magnetic-field-induced structural phase transition is developed. The mechanism of the phase transition is connected with the cooperative Jahn-Teller effect. For a set of microscopic parameters determined earlier the anomalies in the acoustic, magnetic, and magnetoelastic properties have been analyzed for a wide range of temperature and external magnetic fields. Special attention is paid to the

Michael D. Kaplan; George O. Zimmerman

1997-01-01

18

Quadrupolar Waves in Uranium Dioxide  

NASA Astrophysics Data System (ADS)

In presence of active orbital degrees of freedom, elementary excitations around a broken-symmetry state may include multipolar waves, but none of these exotic dispersive excitation branches has ever been identified. We show that quadrupolar waves constitute a major component of the dynamics of uranium dioxide in its magnetoquadrupolar ordered phase, and that many unexplained features in existing inelastic neutron scattering data, including a whole excitation branch, are associated with these propagating quadrupolar fluctuations. Our model permits us to separate the role of Jahn-Teller and superexchange mechanisms as sources of quadrupolar interactions.

Carretta, S.; Santini, P.; Caciuffo, R.; Amoretti, G.

2010-10-01

19

Magnetic-field-induced localization of quasiparticles in underdoped La(2-x)SrxCuO4 single crystals.  

PubMed

Magnetic-field-induced ordering of electrons around vortices is a striking phenomenon recently found in high-T(c) cuprates. To identify its consequence in the quasiparticle dynamics, the magnetic-field (H) dependence of the low-temperature thermal conductivity kappa of La(2-x)SrxCuO4 crystals is studied for a wide doping range. It is found that the behavior of kappa(H) in the subkelvin region changes drastically across optimum doping, and the data for underdoped samples are indicative of unusual magnetic-field-induced localization of quasiparticles; this localization phenomenon is probably responsible for the unusual "insulating normal state" under high magnetic fields. PMID:12688958

Sun, X F; Komiya, Seiki; Takeya, J; Ando, Yoichi

2003-03-19

20

Impurities in magnetic-field-induced Luttinger liquid  

NASA Astrophysics Data System (ADS)

It has been shown recently(C. Biagini, D. L. Maslov, M. Yu. Reizer and L. I. Glazman, `` Magnetic-field-induced Luttinger liquid''), cond-mat/0006407. that a strong magnetic field applied to a bulk metal may induce a Luttinger liquid phase. This is a consequence of the reduced effective dimensionality of charge carriers from 3D to 1D, an effect which is most pronounced in the ultra-quantum limit, when only the lowest Landau level remains populated. We study the effect of impurities in this system. For the case of a point impurity, the calculation of the scattering cross section at a single impurity can be mapped exactly to a 1D problem of tunneling conductance through a barrier for interacting electrons, solved by Yue et al.(D. Yue, L. I. Glazman and K. A. Matveev, Phys. Rev. B 49) (1994) 1966.. Using this mapping, we find that the longitudinal (?=+1) and transverse (?=-1) Drude conductivities exhibit the scaling laws ?_?? T^??, where ?=2e^2|ln?l_B|/? v_F, and vF and ? are the B-dependent Fermi velocity and screening wavevector, respectively; lB is the magnetic length. The physical reason for such a behavior of the conductivity is the almost 1D form of the Friedel oscillation around a single point impurity in the strong magnetic field.

Tsai, Shan-Wen; Maslov, Dmitrii L.; Glazman, Leonid I.

2001-03-01

21

Role of hyperfine coupling in magnetic and quadrupolar ordering of pr_{3}pd_{20}si_{6}.  

PubMed

We study the ternary clathrate Pr_{3}Pd_{20}Si_{6} in specific heat and ac susceptibility measurements on a high-quality single crystal, distinguishing antiferromagnetic and antiferroquadrupolar ordering, as well as a hitherto unknown magnetic low-temperature transition. The specific heat shows the direct involvement of nuclear spin degrees of freedom in the antiferromagnetic ordering, which is well supported by our calculation of the hyperfine level scheme without adjustable parameters. Pr_{3}Pd_{20}Si_{6} is, therefore, one of the rare materials where the nuclear moments are involved in the formation of the magnetic ground state. PMID:23992079

Steinke, L; Mitsumoto, K; Miclea, C F; Weickert, F; Dönni, A; Akatsu, M; Nemoto, Y; Goto, T; Kitazawa, H; Thalmeier, P; Brando, M

2013-08-14

22

Role of Hyperfine Coupling in Magnetic and Quadrupolar Ordering of Pr3Pd20Si6  

NASA Astrophysics Data System (ADS)

We study the ternary clathrate Pr3Pd20Si6 in specific heat and ac susceptibility measurements on a high-quality single crystal, distinguishing antiferromagnetic and antiferroquadrupolar ordering, as well as a hitherto unknown magnetic low-temperature transition. The specific heat shows the direct involvement of nuclear spin degrees of freedom in the antiferromagnetic ordering, which is well supported by our calculation of the hyperfine level scheme without adjustable parameters. Pr3Pd20Si6 is, therefore, one of the rare materials where the nuclear moments are involved in the formation of the magnetic ground state.

Steinke, L.; Mitsumoto, K.; Miclea, C. F.; Weickert, F.; Dönni, A.; Akatsu, M.; Nemoto, Y.; Goto, T.; Kitazawa, H.; Thalmeier, P.; Brando, M.

2013-08-01

23

Irreversible magnetic-field-induced antiferromagnetic to ferromagnetic transition in Nd5Ge3  

NASA Astrophysics Data System (ADS)

Magnetic phase transitions in the rare-earth intermetallic compound Nd5Ge3 have been investigated using a single crystal. Magnetic measurements confirm that Nd5Ge3 is in the antiferromagentic state below TN=51 K, in literature. An irreversible magnetic-field-induced antiferromagentic to ferromagnetic transition has been found below Tt=26 K. In this state, a metamagnetic transition takes place in the first magnetizing process; a ferromagnetic state having a remanent magnetization MR is stabilized after removing the external magnetic field. MR does not show noticeable relaxation behavior and a rectangular-type hysteresis loop is maintained in the following magnetization process. As origin of the irreversibility, a martensitic structural phase transition under the external field can be considered. The magnetic-field cooling effect on the magnetic susceptibility indicates the coexistence of a kind of spin-glass state with long-range antiferromagnetic ordering.

Tsutaoka, Takanori; Tanaka, Akira; Narumi, Yasuo; Iwaki, Masahiro; Kindo, Koichi

2010-01-01

24

Temperature and magnetic field induced multiple magnetic transitions in DyAg(2).  

PubMed

The magnetic properties of the rare-earth intermetallic compound DyAg(2) are studied in detail with the help of magnetization and heat capacity measurements. It is shown that the multiple magnetic phase transitions can be induced in DyAg(2) both by temperature and magnetic field. The detailed magnetic phase diagram of DyAg(2) is determined experimentally. It was already known that DyAg(2) undergoes an incommensurate to commensurate antiferromagnetic phase transition close to 10 K. The present experimental results highlight the first order nature of this phase transition, and show that this transition can be induced by magnetic field as well. It is further shown that another isothermal magnetic field induced transition or metamagnetic transition exhibited by DyAg(2) at still lower temperatures is also of first order nature. The multiple magnetic phase transitions in DyAg(2) give rise to large peaks in the temperature dependence of the heat capacity below 17 K, which indicates its potential as a magnetic regenerator material for cryocooler related applications. In addition it is found that because of the presence of the temperature and field induced magnetic phase transitions, and because of short range magnetic correlations deep inside the paramagnetic regime, DyAg(2) exhibits a fairly large magnetocaloric effect over a wide temperature window, e.g., between 10 and 60 K. PMID:21406918

Arora, Parul; Chattopadhyay, M K; Sharath Chandra, L S; Sharma, V K; Roy, S B

2011-01-19

25

Magnetic field induced phase transformation in polycrystalline NiCoMnAl thin films  

NASA Astrophysics Data System (ADS)

NiCoMnAl thin films were deposited onto unheated substrates using dc magnetron co-sputtering. The microstructure of as-deposited films consisted of nanocrystals in an amorphous matrix and did not exhibit a martensitic phase transformation. After heat treatment, films crystallized into a B2 austenite phase, which exhibited a magnetic field induced martensitic phase transformation. The level of the change in the martensitic transformation temperatures in the magnetic field was determined to be ~2.1 K/T. The films exhibited non-reversible magnetic field induced martensite to austenite transformation due to the large thermal hysteresis.

Rios, S.; Bufford, D.; Karaman, I.; Wang, H.; Zhang, X.

2013-09-01

26

Vortex dynamics and the Fulde-Ferrell-Larkin-Ovchinnikov state in a magnetic-field-induced organic superconductor.  

PubMed

Under special conditions, a superconducting state where the order parameter oscillates in real space, the so-called FFLO state, is theoretically predicted to exist near the upper critical field, as first proposed by Fulde and Ferrell, and Larkin and Ovchinnikov. We report systematic measurements of the interlayer resistance in high magnetic fields to 45 T in the two-dimensional magnetic-field-induced organic superconductor lambda-(BETS)2FeCl4, where BETS is bis(ethylenedithio)tetraselenafulvalene. The resistance is found to show characteristic dip structures in the superconducting state. The results are consistent with pinning interactions between the vortices penetrating the insulating layers and the order parameter of the FFLO state. This gives strong evidence for an oscillating order parameter in real space. PMID:17155350

Uji, S; Terashima, T; Nishimura, M; Takahide, Y; Konoike, T; Enomoto, K; Cui, H; Kobayashi, H; Kobayashi, A; Tanaka, H; Tokumoto, M; Choi, E S; Tokumoto, T; Graf, D; Brooks, J S

2006-10-09

27

Enhancement of magnetic-field-induced strain in Ni–Fe–Ga–Co Heusler alloy  

Microsoft Academic Search

The mobility of the twin boundary and the magnetocrystalline anisotropy constant K at 300K in the martensite phase of Ni51Fe18Ga27Co3 with a 7-layered (14M) structure are estimated. The martensite phase exhibits a large magnetic-field-induced strain of about 0.7% at 300K.

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

2005-01-01

28

High-magnetic-field-induced insulating phase in an organic conductor  

Microsoft Academic Search

We report electrical transport, skin depth, and magnetocaloric measurements in the tau-phase series of organic conductors at very high magnetic fields. In the field range above 36 T these materials show a magnetic field induced phase transition from a metallic to an insulating state. The transition, which is a bulk thermodynamic phenomenon, is Pauli, rather than orbital, in origin.

J. S. Brooks; D. Graf; E. S. Choi; L. Balicas; K. Storr; C. H. Mielke; G. C. Papavassiliou

2003-01-01

29

Contribution of the magnetic field induced by the current passing through a spin-valve element  

Microsoft Academic Search

In situ experiments in a Lorentz microscope have been performed on active spin-valve elements, and a correlation between magnetoresistance and the magnetic domain structure is shown. The presence of a magnetic field induced by the applied current is clearly demonstrated. A simple model is presented, which is in good agreement with the experimental data. In addition, the effect of stray-field

X Portier; A. K Petford-Long; T. C Anthony; J. A Brug

1998-01-01

30

GROWTH OF MAGNETIC FIELDS INDUCED BY TURBULENT MOTIONS  

SciTech Connect

We present numerical simulations of driven magnetohydrodynamic (MHD) turbulence with weak/moderate imposed magnetic fields. The main goal is to clarify dynamics of magnetic field growth. We also investigate the effects of the imposed magnetic fields on the MHD turbulence, including, as a limit, the case of zero external field. Our findings are as follows. First, when we start off simulations with weak mean magnetic field only (or with small scale random field with zero imposed field), we observe that there is a stage at which magnetic energy density grows linearly with time. Runs with different numerical resolutions and/or different simulation parameters show consistent results for the growth rate at the linear stage. Second, we find that, when the strength of the external field increases, the equilibrium kinetic energy density drops by roughly the product of the rms velocity and the strength of the external field. The equilibrium magnetic energy density rises by roughly the same amount. Third, when the external magnetic field is not very strong (say, less than {approx}0.2 times the rms velocity when measured in the units of Alfven speed), the turbulence at large scales remains statistically isotropic, i.e., there is no apparent global anisotropy of order B {sub 0}/v. We discuss implications of our results on astrophysical fluids.

Cho, Jungyeon; Ryu, Dongsu [Department of Astronomy and Space Science, Chungnam National University, Daejeon (Korea, Republic of); Vishniac, Ethan T. [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario L85 4M1 (Canada); Beresnyak, Andrey; Lazarian, A. [Department of Astronomy, University of Wisconsin, Madison, WI 53705 (United States)

2009-03-10

31

Combining magnetic field induced locomotion and supramolecular interaction to micromanipulate glass fibers: toward assembly of complex structures at mesoscale.  

PubMed

The formation of ordered complex structures is one of the most challenging fields in the research of biomimic materials because those structures are promising with respect to improving the physical and mechanical properties of man-made materials. In this letter, we have developed a novel approach to fabricating complex structures on the mesoscale by combining magnetic-field-induced locomotion and supramolecular-interaction-assisted immobilization. We have employed a magnetic field to locomote the glass fiber, which was modified by the layer-by-layer self-assembly of magnetic nanoparticles, to desired positions and have exploited the supramolecular interaction to immobilize glass fiber onto the appointed position. By magnetically induced micromanipulation, we can drive another fiber across the former one and finally obtain a crossing structure, which can lead to more complex structures on the mesocale. Moreover, we have constructed a mesoscale structure, termed "CHEM", to demonstrate further the application of this method. PMID:21542598

Cheng, Mengjiao; Gao, Haitao; Zhang, Yajun; Tremel, Wolfgang; Chen, Jian-Feng; Shi, Feng; Knoll, Wolfgang

2011-05-04

32

Magnetic-field-induced quadrupole coupling in the nuclear magnetic resonance of noble-gas atoms and molecules  

SciTech Connect

An analytic response theory formulation for the leading-order magnetic field-induced and field-dependent quadrupole splitting in nuclear magnetic resonance spectra is presented and demonstrated with first-principles calculations for {sup 21}Ne, {sup 36}Ar, and {sup 83}Kr in noble gas atoms. The case of molecules was studied for {sup 33}S in the sulphur hexafluoride molecule, as well as for {sup 47/49}Ti, {sup 91}Zr, and {sup 177,179}Hf in group(IV) tetrahalides. According to our calculations, the hitherto experimentally unknown field-induced quadrupole splitting in molecules rises to 10{sup 2} Hz for {sup 177,179}Hf nuclei in HfF{sub 4} and 10{sup 1} Hz for {sup 47/49}Ti in TiCl{sub 4}, and is hence of observable magnitude.

Manninen, Pekka [Laboratory of Physical Chemistry, Department of Chemistry, P.O. Box 55 (A.I. Virtasen aukio 1), FIN-00014 University of Helsinki (Finland); NMR Research Group, Department of Physical Sciences, P.O. Box 3000, FIN-90014 University of Oulu (Finland); Vaara, Juha [Laboratory of Physical Chemistry, Department of Chemistry, P.O. Box 55 (A.I. Virtasen aukio 1), FIN-00014 University of Helsinki (Finland); Pyykkoe, Pekka [Laboratory for Instruction in Swedish, Department of Chemistry, P.O. Box 55 (A.I. Virtasen aukio 1), FIN-00014 University of Helsinki (Finland)

2004-10-01

33

Asymmetry of the magnetic field-induced superconducting state BT phase diagram induced by hydrostatic pressure  

Microsoft Academic Search

We investigated, by electrical transport techniques, the effect of hydrostatic pressure on the recently discovered [1,2] magnetic field-induced superconducting state (FISC) of the lambda-(BETS)_2FeCl4 compound. At zero field a small amount of hydrostatic pressure induced, for instance, by the solidification of the pressure medium, considerably ncreases the conductivity of the metallic state at low temperatures. Furthermore, it stabilizes superconductivity at

L. Balicas; J. S. Brooks; K. Storr; S. Uji; H. Kobayashi; A. Kobayashi; M. Tokumoto

2002-01-01

34

Magnetic Field Induced Surface State Study of Conduction Electron Scattering in Fast Neutron Irradiated Copper.  

NASA Astrophysics Data System (ADS)

A study has been made of the electron scattering in fast neutron irradiated copper using magnetic field induced surface states. The experiment involved measurement of the surface impedance at microwave frequencies. Surface impedance oscillations have been observed in fields in the range 0-45 G in the (111) plane of a high purity Cu single crystal. The experiment was conducted at a microwave frequency of 24 GHz and at liquid helium temperatures. The measured spectra showed resonances of considerable magnitude in comparison to those observed in previous works in the (111) plane of Cu. Upon accurately determining the necessary v_{rm z} = 0 zone using the known Fermi surface geometry of Cu, a predetermined Fermi velocity distribution was used to identify the resonant electrons responsible for these signals. Based on this identification, a prediction was made of the resonant field peak locations as a function of magnetic field orientation. The measured peak locations differed from the predicted values by approximately 20%. This discrepancy was attributed to the sliding of the resonance electrons along the zone in addition to the tilting of this nonconstant k _{rm z} zone with respect to the plane of the magnetic field. Using an appropriate scaling factor to account for these effects, together with the Fermi surface location of the contributing electrons, the linewidth and lineshapes of the resonances contained information from which electron scattering rates were extracted. In order to measure the change in electron scattering rate due to a dilute concentration of Frenkel pairs, the sample was subjected to a fast neutron fluence (E > 0.1 MeV) of 2 times 10 ^{15} n/cm^2 and the resonance spectra remeasured. The measured anisotropy of the change in electron scattering rate induced by the Frenkel pairs has been compared to calculations from the Korringa-Kohn-Rostoker (KKR) Green function extended-defect formalism. While general agreement between the scattering rate anisotropies was found to exist, there was a marked exception to this at < 111> neck point. The measured values of scattering rate were significantly lower for this point than predicted by the theory.

Gillen, Thomas James

35

Irreversible dynamics of the phase boundary in U(Ru0.96Rh0.04)2Si2 and implications for ordering.  

PubMed

We report measurements and analysis of the specific heat and magnetocaloric effect-induced temperature changes at the phase boundary into the single magnetic field-induced phase (phase II) of U(Ru0.96Rh0.04)2Si2, which yield irreversible properties similar to those at the valence transition of Yb(1-x)Y(x)InCu4. To explain these similarities, we propose a bootstrap mechanism by which lattice parameter changes caused by an electric quadrupolar order parameter within phase II become coupled to the 5f-electron hybridization, giving rise to a valence change at the transition. PMID:16712010

Silhanek, A V; Jaime, M; Harrison, N; Fanelli, V R; Batista, C D; Amitsuka, H; Nakatsuji, S; Balicas, L; Kim, K H; Fisk, Z; Sarrao, J L; Civale, L; Mydosh, J A

2006-04-05

36

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

SciTech Connect

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.

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

2010-11-17

37

Magnetic-field-induced superconductivity in the antiferromagnetic organic superconductor ?- (BETS)2 Fe Br4  

NASA Astrophysics Data System (ADS)

The high magnetic field electronic state of the quasi-two-dimensional organic superconductor, ?-(BETS)2FeBr4 was investigated by the resistance measurements. At very low temperatures, magnetic-field-induced superconductivity (FISC) was observed under high magnetic field parallel to the conducting layers. The obtained magnetic phase diagrams are well reproduced by Fisher’s theory based on the Jaccarino-Peter compensation mechanism, where the external field and internal field caused by the magnetic moments are canceled out. The analyses of the phase diagram show that the orbital effect is not so small in this compound, which makes the Fulde-Ferrell-Larkin-Ovchinnikov state less likely.

Konoike, T.; Uji, S.; Terashima, T.; Nishimura, M.; Yasuzuka, S.; Enomoto, K.; Fujiwara, H.; Zhang, B.; Kobayashi, H.

2004-09-01

38

Magnetic-Field-Induced Second-Harmonic Generation in Semiconductor GaAs  

NASA Astrophysics Data System (ADS)

We show that application of a magnetic field induces optical second-harmonic generation (SHG) in GaAs. This phenomenon arises from field-induced symmetry breaking causing new optical nonlinearities. A series of narrow SHG lines is observed in the spectral range from 1.52 to 1.77 eV that we attribute to Landau-level quantization of the band energy spectrum. The rotational anisotropy of the SHG signal distinctly differs from that of the electric-dipole approximation. Model calculations reveal that nonlinear magneto-optical spatial dispersion that comes together with the electric-dipole term is the dominant mechanism for this nonlinearity.

Pavlov, V. V.; Kalashnikova, A. M.; Pisarev, R. V.; Sänger, I.; Yakovlev, D. R.; Bayer, M.

2005-04-01

39

The modelling of the toroidal magnetic field induced by tidal ocean circulation  

NASA Astrophysics Data System (ADS)

Observations of the ocean-induced magnetic field by the CHAMP magnetic space mission have the potential to be used as a constraint when examining ocean dynamics. This has initiated theoretical studies on the prediction of the poloidal magnetic field induced by the horizontal ocean-circulation flow. This study deals with the computation and analysis of the toroidal magnetic field induced by the tidal ocean-circulation flow on the background of the main Earth's geomagnetic field. Since the induced toroidal magnetic field cannot be modelled by the single-layer approximation model used to predict the poloidal magnetic field, we treat the ocean as a spherical layer of a finite thickness and compute the toroidal magnetic field by a matrix-propagator technique with a source of electric currents in the ocean layer. Our numerical simulations based on the OMCT tidal ocean velocities show that the induced toroidal magnetic field is extremely sensitive to the vertical gradient of horizontal ocean flow. The larger this gradient, the stronger the induced toroidal magnetic field. Specifically, its magnitudes vary from 10-2 nT for barotropic flow to several nT for baroclinic flow. We show that the induced toroidal magnetic field generated by M2 tidal forcing is comparable in amplitude to the induced poloidal part of the field. The induced toroidal and poloidal magnetic fields differ, however, in their spatial behaviour.

Dostal, Jan; Martinec, Zden?k.; Thomas, Maik

2012-05-01

40

Magnetic field induced metal-insulator transition in a kagome nanoribbon  

NASA Astrophysics Data System (ADS)

In the present work, we investigate two-terminal electron transport through a finite width kagome lattice nanoribbon in presence of a perpendicular magnetic field. We employ a simple tight-binding (T-B) Hamiltonian to describe the system and obtain the transmission properties by using Green's function technique within the framework of Landauer-Büttiker formalism. After presenting an analytical description of energy dispersion relation of a kagome nanoribbon in presence of the magnetic field, we investigate numerically the transmittance spectra together with the density of states and current-voltage characteristics. It is shown that for a specific value of the Fermi energy, the kagome network can exhibit a magnetic field induced metal-insulator transition, which is the central investigation of this communication. Our analysis may be inspiring in designing low-dimensional switching devices.

Dey, Moumita; Maiti, Santanu K.; Karmakar, S. N.

2011-11-01

41

Magnetic-field-induced transformation in FeMnGa alloys  

SciTech Connect

A kind of ferromagnetic shape memory alloy with off-stoichiometric composition of Heusler alloy Fe{sub 2}MnGa has been synthesized. By optimizing composition, the martensitic transformation has been modified to occur at about 163 K accompanying spontaneous magnetization, which enables a magnetic field-induced structural transition from a paramagnetic parent phase to a ferromagnetic martensite with high magnetization of 93.8 emu/g. The material performs a quite large lattice distortion through the transformation, (c-a)/c=33.5%, causing a shape memory strain upto 3.6%. Such large lattice distortions strongly influence the electron structures, and thus some special physical behavior related to the transport and conductive properties is investigated.

Zhu, W.; Liu, E. K.; Feng, L.; Tang, X. D.; Chen, J. L.; Wu, G. H. [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Liu, H. Y.; Meng, F. B.; Luo, H. Z. [School of Material Science and Engineering, Hebei University of Technology, Tianjin 300130 (China)

2009-11-30

42

Magnetic-field-induced transformation in FeMnGa alloys  

NASA Astrophysics Data System (ADS)

A kind of ferromagnetic shape memory alloy with off-stoichiometric composition of Heusler alloy Fe2MnGa has been synthesized. By optimizing composition, the martensitic transformation has been modified to occur at about 163 K accompanying spontaneous magnetization, which enables a magnetic field-induced structural transition from a paramagnetic parent phase to a ferromagnetic martensite with high magnetization of 93.8 emu/g. The material performs a quite large lattice distortion through the transformation, (c-a)/c=33.5%, causing a shape memory strain upto 3.6%. Such large lattice distortions strongly influence the electron structures, and thus some special physical behavior related to the transport and conductive properties is investigated.

Zhu, W.; Liu, E. K.; Feng, L.; Tang, X. D.; Chen, J. L.; Wu, G. H.; Liu, H. Y.; Meng, F. B.; Luo, H. Z.

2009-11-01

43

Magnetic-Field-Induced Insulator-Conductor Transition in SU(2) Quenched Lattice Gauge Theory  

SciTech Connect

We study the correlator of two vector currents in quenched SU(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 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.

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

2010-09-24

44

Magnetic-field-induced martensitic transformations in Ni47 - x Mn42 + x In11 alloys (with 0 ? x ? 2)  

NASA Astrophysics Data System (ADS)

Magnetic properties and martensitic transformations in the Ni47 - x Mn42 + x In11 alloys (with 0 ? x ? 2) have been studied. The magnetic-field-induced martensitic transformation was found to be observed for all the alloys. The critical temperatures of magnetic and structural phase transformations, temperature dependences of spontaneous magnetization of austenite and martensite, and the critical field, at which the martensitic transformation occurs, have been determined based on magnetic measurements performed for the alloys under study. The spontaneous magnetization of the alloys in the martensitic state has been shown to be lower than that in the magnetic-field-induced austenitic state by a factor of six.

Kaletina, Yu. V.; Gerasimov, E. G.; Schastlivtsev, V. M.; Fokina, E. A.; Terent'ev, P. B.

2013-10-01

45

Quadrupolar phase transitions in UPd3  

NASA Astrophysics Data System (ADS)

Quadrupolar order in a 5f electron system has been observed directly for the first time, using x-ray scattering techniques [1]. In UPd3, 2 sets of satellite peaks appear at low temperatures, and show resonant enhancement at the uranium MIV edge. X-ray and neutron scattering, and bulk property measurements, reveal a total of 4 phase transitions in UPd3 below 8K, which we associate with different quadrupolar order parameters. We have now developed a new model for the crystal field states of UPd3 that enables us to explain not only the order parameters of the 4 phase transitions, but also the excitations in the ordered phases, as observed in our inelastic neutron scattering studies of UPd3. [1] D.F.McMorrow, K.A.McEwen, U.Steigenberger, H.M.Ronnow, F.Yakhou, Phys. Rev. Lett. 87 (2001) 057201

McEwen, Keith

2003-03-01

46

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

NASA Astrophysics Data System (ADS)

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

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

2012-02-01

47

Fast deswelling of nanocomposite polymer hydrogels via magnetic field-induced heating for emerging FO desalination.  

PubMed

Freshwater shortage is one of the most pressing global issues. Forward osmosis (FO) desalination technology is emerging for freshwater production from saline water, which is potentially more energy-efficient than the current reverse osmosis process. However, the lack of a suitable draw solute is the major hurdle for commercial implementation of the FO desalination technology. We have previously reported that thermoresponsive hydrogels can be used as the draw agent for a FO process, and this new hydrogel-driven FO process holds promise for further development for practical application. In the present work, magnetic field-induced heating is explored for the purpose of developing a more effective way to recover water from swollen hydrogel draw agents. The composite hydrogel particles are prepared by copolymerization of sodium acrylate and N-isopropylacrylamide in the presence of magnetic nanoparticles (?-Fe2O3, <50 nm). The results indicate that the magnetic heating is an effective and rapid method for dewatering of hydrogels by generating the heat more uniformly throughout the draw agent particles, and thus, a dense skin layer commonly formed via conventional heating from the outside of the particle is minimized. The FO dewatering performance is affected by the loading of magnetic nanoparticles and magnetic field intensity. Significantly enhanced liquid water recovery (53%) is achieved under magnetic heating, as opposed to only around 7% liquid water recovery obtained via convection heating. Our study shows that the magnetic heating is an attractive alternative stimulus for the extraction of highly desirable liquid water from the draw agent in the polymer hydrogel-driven forward osmosis process. PMID:23663180

Razmjou, Amir; Barati, Mohammad Reza; Simon, George P; Suzuki, Kiyonori; Wang, Huanting

2013-05-29

48

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

PubMed Central

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.

Lai, Henry; Singh, Narendra P

2004-01-01

49

The Magnetic-Field-Induced Birefringence of the Mixtures of the Chiral Molecules and the Ferronematic Liquid Crystals  

Microsoft Academic Search

The ferronemtaic state which was described theoretically by Brochard and de Gennes can be achieved by doping the liquid crystal with anisotropic ferromagnetic particles. The homeotropic liquid crystal film was successfully prepared for the ferronematic liquid crystal doped with low concentration chiral molecules.The magnetic-field-induced-birefringence due to molecular reorientation was treated both theoretically and experimentally. In the low field regime (<2.5G),

Shu-Hsia Chen; S. H. Chiang

1987-01-01

50

Anisotropic magnetic-field-induced crossover from a pseudogap to a heavy-fermion state in CeNiSn  

NASA Astrophysics Data System (ADS)

Using the break-junction tunneling technique in magnetic fields up to 20 T, a magnetic-field-induced crossover from a pseudogap to a metallic heavy-fermion state has been observed in CeNiSn. The pseudogap at the Fermi level which opens at T<10 K, was suppressed by a magnetic field applied along the a axis but was not affected for a field along the b axis.

Davydov, D. N.; Kambe, S.; Jansen, A. G. M.; Wyder, P.; Wilson, N.; Lapertot, G.; Flouquet, J.

1997-03-01

51

Thermodynamics of the magnetic-field-induced "normal" state in an underdoped high Tc superconductor  

NASA Astrophysics Data System (ADS)

High magnetic fields are used to kill superconductivity and probe what happens to system when it cannot reach the ideal ground state, i.e. what is the normal-state ground state? Early work in High-Tc, where the application of magnetic field destroyed the zero resistance state and recovered a resistivity value that connected continuously with the zero field curve, lead people to believe this magnetic-field-induced-state had fully driven the system normal, revealing the true underlying ground state, without any vestige of superconductivity. Many experiments done in this region of phase space have results interpreted as coming from the low energy ground state excitations. With the emergence of ultra-clean crystals in a unique family of hole doped high-Tc superconductors, YBa2Cu3O 7-delta, YBCO, a new and highly unexpected phenomena of quantum oscillations were discovered, and they followed the standard Liftshitz-Kosevich (LK) theory for a normal metal. The results suddenly made the problem of high-T c appear to be analogous to superconductivity in the organics, which is brought about by a wave-vector nesting and Fermi surface reconstruction. The only problem, it appeared, that needed to be reconciled was with Angle Resolved Photo-Emission Spectroscopy (ARPES) and Scanning Tunneling Microscopy (STM) data that claimed to see no such Fermi surface, instead only "arcs", a set of disconnected segments in the Brillouin zone which quasiparticle peaks are observed at the Fermi energy, which in a mean field description does not allow for a continuous Fermi surface contour. These two discrepancies led to the "arc vs pocket" debate, which is still unresolved. The other kink in the quantum oscillation armor is that, to this date, quantum oscillations in the hole-doped cuprates have only been seen in YBCO, the only cuprate structure to have CuO chains, which conduct and are located in between two CuO2 superconducting planes in the unit cell. In an attempt to reconcile the "arc vs pocket" debate we measure specific heat on an ultra-clean de-twinned single crystal of underdoped YBCO 6.56 with a Tc = 60 K, up to fields twice irreversibility field, define as the onset of the resistive transition. The zero temperature extrapolation of the electronic contribution to the specific heat, gamma, is the total quasiparticle density of states. For a two-dimensional system with parabolic energy bands, gamma is simply the sum of each pocket multiplied by its effective mass. Therefore, by determining gamma at high fields and using previously determined values for the effective mass from quantum oscillation transport measurements we can simply play a counting game to determine the number of pockets in the Fermi surface. Furthermore, at low fields the response to the specific heat as a function of magnetic field in a d-wave superconductor is known to have a (H) dependence, and we can look for deviations from this (H) , which are expected to happen when the system is no longer in a superconducting state. Results from our specific heat experiment shed new light on the true nature of the magnetic field induced "normal" state, and should force reinterpretation of many experimental findings. The specific heat measurements foremost show a smooth evolution of gamma from low to high magnetic fields which follows a Ac (H) dependence, with the prefactor, Ac giving the correct magnitude for the anisotropy of the d-wave superconducting gap. This means with the application of magnetic fields strong enough to restore the resistive state, the superconducting gap still exits. Additionally, we see quantum oscillations that follow conventional LK formalism and can determine an effective mass uniquely, where no fitting parameters are required. Interestingly, these oscillations fit on top of the (H) finding. How can the (H) and quantum oscillation whose phenomena arise from very different physics be reconciled? Looking at our own zero field gamma value of 1.85 mJ mol-1 K-2, which is intrinsic for YBCO, allows the pocket counting game

Riggs, Scott Chandler

52

Martensitic transformation and magnetic-field-induced strain in Ni-Mn-Ga magnetic shape memory alloys  

NASA Astrophysics Data System (ADS)

The present paper deals with the thermal- and stress-induced martensitic transformations, effects of bias magnetic field and external compressive stress on transformation- and magnetic-field-induced strain in Ni-Mn-Ga alloys. The effect of the external magnetic field and compressive stress on the reorientation of martensitic variants is discussed. It is found that the stress-induced spear-like martensitic crystal forms at the beginning of loading at the temperature a little higher than Ms. The interfaces between the parent phase and the stress-induced martensite migrate reversibly under the increasing/decreasing stress, showing the characteristics of thermoelastic martensitic transformation. When the Ni{52}Mn{24}Ga{24} single crystal is cooled down to 200K, an intermartensitie transformation occurs, however there is no appearance of this case for the powder sample of the same alloy with average particle size ofabout 50 ?m. About 1.8% magnetic-field-induced strain is obtained in the [100] direction of Ni2MnGa singte crystal when a 1.5T pulse magnetic field is applied at the Ms temperature.

Zhao, L. C.; Gao, Z. Y.; Cai, W.

2003-10-01

53

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

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.

Coffey, D.

1991-01-01

54

Microwave complex permeability of Fe3O4 nanoflake composites with and without magnetic field-induced rotational orientation  

NASA Astrophysics Data System (ADS)

Magnetite (Fe3O4) nanoflakes with widths of 100-200 nm and thicknesses of 10-80 nm were prepared by a hydrothermal synthesis method. Fe3O4 nanoflake composites with and without magnetic field-induced rotational orientation of flake planes of Fe3O4 nanoflakes in paraffin binder were fabricated using 35 wt. % Fe3O4 nanoflakes. The rotationally oriented composite showed higher permeability and resonance frequency than the nonoriented one, and its value of (?0-1)fr reached 214.8 GHz and exceeded the Snoek's limit. Considering a uniform and a random distribution of flake planes of Fe3O4 nanoflakes in the oriented and nonoriented composites, respectively, the complex permeability of both composites was calculated using the Landau-Lifshitz-Gilbert equation and the Bruggeman's effective medium theory in the 2-18 GHz microwave frequency range.

Liu, Xianguo; Wing Or, Siu; Ming Leung, Chung; Ho, S. L.

2013-05-01

55

Magnetic-field-induced quantum criticality in a spin- S planar ferromagnet with single-ion anisotropy  

NASA Astrophysics Data System (ADS)

The effects of single-ion anisotropy on quantum criticality in a d-dimensional spin- S planar ferromagnet is explored by means of the two-time Green's function method. We work at the Tyablikov decoupling level for exchange interactions and the Anderson-Callen decoupling level for single-ion anisotropy. In our analysis a longitudinal external magnetic field is used as the non-thermal control parameter and the phase diagram and the quantum critical properties are established for suitable values of the single-ion anisotropy parameter D. We find that the single-ion anisotropy has sensible effects on the structure of the phase diagram close to the quantum critical point. However, for values of the uniaxial crystal-field parameter below a positive threshold, the conventional magnetic-field-induced quantum critical scenario remains unchanged.

Mercaldo, M. T.; Rabuffo, I.; De Cesare, L.; Caramico D'Auria, A.

2013-08-01

56

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

NASA Astrophysics Data System (ADS)

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 1020T. 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.

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

2013-09-01

57

Dynamic-angle spinning of quadrupolar nuclei  

NASA Astrophysics Data System (ADS)

In dynamic-angle spinning (DAS), a sample spins around an axis inclined at an angle ?(t) with respect to the magnetic field such that the averages of Pn(cos?) are zero. The simplest case is where ?(t) assumes two discrete values ?1 and ?2 (complementary DAS angles) such that the averages of P2(cos?) and P4(cos?) are zero, thereby removing second-order quadrupolar (and dipolar) broadening. Examples of DAS complementary angles are ?1=37.38° and ?2=79.18°. Experimental details for DAS experiments are provided and applications to sodium-23 and oxygen-17 NMR illustrate the enhanced resolution achieved by removing the second-order broadening inherent in magic-angle spinning.

Mueller, K. T.; Sun, B. Q.; Chingas, G. C.; Zwanziger, J. W.; Terao, T.; Pines, A.

2011-12-01

58

Magnetic-field induced multiferroicity in a quantum critical frustrated spin liquid  

NASA Astrophysics Data System (ADS)

Dielectric spectroscopy is used to check for the onset of polar order in the quasi-one-dimensional quantum spin system Sul-Cu2Cl4 when passing from the spin-liquid state into the ordered spiral phase in an external magnetic field. We find clear evidence for multiferroicity in this material and treat in detail its H-T phase diagram close to the quantum critical regime.

Schrettle, F.; Krohns, S.; Lunkenheimer, P.; Loidl, A.; Wulf, E.; Yankova, T.; Zheludev, A.

2013-03-01

59

High-field QCPMG NMR of large quadrupolar patterns using resistive magnets  

SciTech Connect

Spectroscopy in a high magnetic field reduces second-order quadrupolar shift while increasing chemical shift. It changes the scale between quadrupolar spins. The application of QCPMG multiple echo acquisition under the high magnetic field of a 25T resistive magnet are presented for acquiring large quadrupolar patterns. It shows that temporal field fluctuations and spatial homogeneity of the Keck magnet at the hundreds to thousands of kilohertz can be efficiently recorded using a combination of QCPMG and magnetic field stepping with negligible hindrance from the inhomogeneity and field fluctuations of powered magnets.

Hung, Ivan; Shetty, Kiran; Ellis, Paul D.; Brey, William W.; Gan, Zhehong

2009-12-01

60

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

SciTech Connect

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.

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

61

MnAs: magnetic-field-induced structural phase transformation and associated magnetoresistance  

NASA Astrophysics Data System (ADS)

MnAs, a commercially available material first studied a century ago, exhibits a first-order phase transition from a ferromagnetic, high-spin metal NiAs-type hexagonal phase to a paramagnetic, lower-spin insulator MnP-type orthorhombic phase at T_C= 313 K. We report the results of neutron diffraction experiments showing that an external magnetic field, B, stabilizes the hexagonal metallic phase above T_C. The phase transformation is reversible and constitutes the first demonstration of a bond-breking transition induced by a magnetic field. At 322 K the hexagonal structure is restored for B > 4 tesla. The field-induced phase transition is accompanied by an enhanced magnetoresistance of about 17 % at 310 K. We discuss the origig of this phenomenon, which appears to be similar to that of the colossal magnetoresistance response observed in some members of the manganese perovskite family.

Mira, Jorge; Rivadulla, Francisco; Rivas, Jose; Fondado, Alfonso; Caciuffo, Roberto G. M. C.; Carsughi, F.; Guidi, Tatiana; Goodenough, John B.

2003-03-01

62

Magnetic field-induced acceleration of the accumulation of magnetic iron oxide nanoparticles by cultured brain astrocytes.  

PubMed

Magnetic iron oxide nanoparticles (Fe-NPs) are considered for various biomedical and neurobiological applications that involve the presence of external magnetic fields. However, little is known on the effects of a magnetic field on the uptake of such particles by brain cells. Cultured brain astrocytes accumulated dimercaptosuccinate-coated Fe-NP in a time-, temperature-, and concentration-dependent manner. This accumulation was strongly enhanced by the presence of the magnetic field generated by a permanent neodymium iron boron magnet that had been positioned below the cells. The magnetic field-induced acceleration of the accumulation of Fe-NP increased almost proportional to the strength of the magnetic field applied, increasing the cellular-specific iron content from an initial 10 nmol/mg protein within 4 h of incubation at 37°C to up to 12,000 nmol/mg protein. However, presence of a magnetic field also increased the amounts of iron that attached to the cells during incubation with Fe-NP at 4°C. These results suggest that the presence of an external magnetic field promotes in cultured astrocytes both the binding of Fe-NP to the cell membrane and the internalization of Fe-NP. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011. PMID:22065542

Lamkowsky, Marie-Christin; Geppert, Mark; Schmidt, Maike M; Dringen, Ralf

2011-11-01

63

Asymmetry of the magnetic field-induced superconducting state B-T phase diagram induced by hydrostatic pressure  

NASA Astrophysics Data System (ADS)

We investigated, by electrical transport techniques, the effect of hydrostatic pressure on the recently discovered [1,2] magnetic field-induced superconducting state (FISC) of the ?-(BETS)_2FeCl4 compound. At zero field a small amount of hydrostatic pressure induced, for instance, by the solidification of the pressure medium, considerably ncreases the conductivity of the metallic state at low temperatures. Furthermore, it stabilizes superconductivity at TC ~= 5.5 K and suppresses the transition towards the insulating Néel state, from TN = 8.5 K at p = 1 bar, to TN ~= 3.5 K. The application of hydrostatic pressure does not seem to affect neither the transition temperature towards the FISC state nor the mechanism responsible for its suppression at very high fields. Nevertheless, it displaces the phase boundary between the metallic and FISC states towards much lower critical fields. This asymmetry, in the T-B phase diagram, is not easily conciliated with the original description of the FISC state in terms of the so-called Jaccarino-Peter compensation effect [2]. [1] S. Uji, et al., Nature 410, 908 (2001). [2] L. Balicas, J. S. Brooks, K. Storr, S. Uji, M. Tokumoto, H. Tanaka, H. Kobayashi, A. Kobayashi, V. Barzykin, and L. P. Gor'kov, Phys. Rev. Lett. 87, 067002 (2001).

Balicas, L.; Brooks, J. S.; Storr, K.; Uji, S.; Kobayashi, H.; Kobayashi, A.; Tokumoto, M.

2002-03-01

64

Magnetic-field-induced second-harmonic generation in the diluted magnetic semiconductors Cd1-xMnxTe  

NASA Astrophysics Data System (ADS)

Magnetic-field-induced second-harmonic generation (MFISH) has been studied in diluted magnetic semiconductors Cd1-xMnxTe (0.001

Sänger, I.; Kaminski, B.; Yakovlev, D. R.; Pisarev, R. V.; Bayer, M.; Karczewski, G.; Wojtowicz, T.; Kossut, J.

2006-12-01

65

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

NASA Astrophysics Data System (ADS)

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.

Kapcia, Konrad; Robaszkiewicz, Stanis?aw

2013-02-01

66

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

PubMed

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

Kapcia, Konrad; Robaszkiewicz, Stanis?aw

2013-02-13

67

Magnetic-field-induced orientation of photosynthetic reaction centers as revealed by time-resolved W-band EPR of spin-correlated radical pairs  

SciTech Connect

The spin-polarized W-band EPR spectra of the secondary radical pair in plant photosystem 1 indicate a magnetic-field-induced orientation of the photosynthetic reaction centers in the field of the EPR spectrometer. This orientation arises due to the anisotropy of the diamagnetic susceptibility of the reaction center protein. Analysis of the angular-dependent EPR spectra on the basis of the spin-correlated radical pair concept provides new information on the cofactor arrangement in plant photosystem 1.

Berthold, T.; Bechtold, M.; Heinen, U.; Link, G.; Poluektov, O.; Utschig, L.; Tang, J.; Thurnauer, M.C.; Kothe, G.

1999-12-09

68

Magnetic Field Induced Insulating Phase in Two-Dimensional Electron Gas in InGaAs\\/InP: The Wigner Solid  

Microsoft Academic Search

We review the results of our study of the properties of the magnetic field induced insulating phase in a two-dimensional electron gas in modulation-doped In0.53Ga0.47As\\/InP heterostructures. The experiments were performed in the millikelvin range of temperatures in very high magnetic fields. The results can be explained by the assumption of the formation of a glassy Wigner solid.

B. Pödör; Gy. Kovács; G. Reményi; I. G. Savel'ev; S. V. Novikov

2001-01-01

69

Theoretical investigation of magnetic-field-induced 2p53s 3P0,2 - 2p6 1S0 transitions in Ne-like ions without nuclear spin  

NASA Astrophysics Data System (ADS)

We report theoretical results for magnetic-field-induced 2p53s3P0,2-2p61S0 E1 transitions in Ne-like ions with zero nuclear spin (I=0) between Mg iii and Zn xxi as well as in Ne i. We demonstrate that it is important to include both “perturber” states 2p53s1P1 and 2p53s3P1 in order to produce reliable transition rates. Furthermore, we investigate the trends of the rates along the isoelectronic sequence of the 2p53s3P0,2-2p61S0 transitions and their competition with the 2p53s3P0-2p53s3P1 M1 and the 2p53s3P2-2p61S0 M2 decays. For the 2p53s3P0 state the magnetic-field-induced transition becomes the dominant decay channel for the light elements even in a relatively weak magnetic field, and it will therefore prove useful in diagnostics of the strength of magnetic fields in different plasmas. The influence of an external magnetic field on the lifetime of the 2p53s3P2 state is much smaller but still observable for the ions near the neutral end of the sequence. As a special case, the magnetic field effect on the lifetimes of 2p53s3P0,2 states of neutral 20Ne is discussed. It is found that the lifetimes are drastically reduced by a magnetic field, which may be an underlying reason for the discrepancies in the lifetime of the 2p53s3P2 state between experiment [14.73(14) s] and theory (17.63 s).

Li, Jiguang; Grumer, Jon; Li, Wenxian; Andersson, Martin; Brage, Tomas; Hutton, Roger; Jönsson, Per; Yang, Yang; Zou, Yaming

2013-07-01

70

Probing Quadrupolar Nuclei by Solid-State NMR Spectroscopy: Recent Advances  

SciTech Connect

Solid-state nuclear magnetic resonance (NMR) of quadrupolar nuclei has recently undergone remarkable development of capabilities for obtaining structural and dynamic information at the molecular level. This review summarizes the key achievements attained during the last couple of decades in solid-state NMR of both integer spin and half-integer spin quadrupolar nuclei. We provide a concise description of the first- and second-order quadrupolar interactions, and their effect on the static and magic angle spinning (MAS) spectra. Methods are explained for efficient excitation of single- and multiple-quantum coherences, and acquisition of spectra under low- and high-resolution conditions. Most of all, we present a coherent, comparative description of the high-resolution methods for half-integer quadrupolar nuclei, including double rotation (DOR), dynamic angle spinning (DAS), multiple-quantum magic angle spinning (MQMAS), and satellite transition magic angle spinning (STMAS). Also highlighted are methods for processing and analysis of the spectra. Finally, we review methods for probing the heteronuclear and homonuclear correlations between the quadrupolar nuclei and their quadrupolar or spin-1/2 neighbors.

Fernandez, Christian; Pruski, Marek

2011-06-08

71

Homonuclear correlation experiments for quadrupolar nuclei, spinning away from the magic angle.  

PubMed

We present a set of homonuclear correlation experiments for half-integer quadrupolar spins in solids. In all these exchange-type experiments, the dipolar interaction is retained during the mixing time by spinning the sample at angles other than the "regular magic angle" (54.7 degrees celsius). The second-order quadrupolar interaction is averaged by different strategies for the different experiments. The multiple-quantum off magic angle spinning (MQOMAS) exchange experiment is essentially a regular MQMAS experiment where the quadrupolar interaction is averaged by combining magic angle spinning with a multiple- to single-quantum correlation scheme. The sample is spun at the magic angle at all times except during the mixing time which is added to establish homonuclear correlation. In the multiple-quantum P4 magic angle spinning (MQP4MAS) exchange experiment, the sample is spun at one of the angles at which the fourth-order Legendre polynomial vanishes (P4 magic angle), the remaining second-order quadrupolar interaction now governed by a second-rank tensor is refocussed by the multiple to single-quantum correlation scheme. In the dynamic angle spinning (DAS) exchange experiment, the second-order quadrupolar interaction is averaged by correlating the evolution from two complementary angles. These experiments are demonstrated and compared, in view of their specific advantages and disadvantages, for 23Na in the model compound Na2SO3. PMID:15388182

Ajithkumar, T G; van Eck, E R H; Kentgens, A P M

72

A magnetic-field-induced irreversible transition in geometrically frustrated antiferromagnetic TbBaCo4O7 with kagome and triangular lattices  

NASA Astrophysics Data System (ADS)

The temperature dependences M(T) and field dependences M(H) of the magnetization have been measured in single-crystal TbBaCo4O7 for two magnetic-field directions: H?c and H?c. In the case of H?c, a magnetic field-induced irreversible transition is detected at low temperatures, accompanied by magnetization jumps on the M(H) dependences. It is shown that the transition field depends on the rate at which the external magnetic field is introduced.

Bludov, A. N.; Gnatchenko, S. L.; Szymczak, R.; Szymczak, H.; Barilo, S. N.; Bychkov, G. L.; Shiryaev, S. V.

2009-12-01

73

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

SciTech Connect

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.

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

74

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

SciTech Connect

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.

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

75

Magnetic Field Induced Phase Transitions in Gd5(Si1.95Ge2.05)Single Crystal and the Anisotropic Magnetocaloric Effect  

SciTech Connect

The magnetization measurements using a Gd{sub 5}(Si{sub 1.95}Ge{sub 2.05}) single crystal with the magnetic field applied along three crystallographic directions, [001], [010] and [100], were carried out as function of applied field (0-56 kOe) at various temperatures ({approx}5-320 K). The magnetic-field induced phase transformations at temperature above the zero-field critical temperature, i.e. the paramagnetic (PM) {leftrightarrow} ferromagnetic (FM) transitions with application or removal of magnetic field, are found to be temperature dependent and hysteretic. The corresponding critical fields increase with increasing temperature. The magnetic field (H)-temperature (T) phase diagrams have been constructed for the Gd{sub 5}(Si{sub 1.95}Ge{sub 2.05}) single crystal with field along the three directions. A small anisotropy has been observed. The magnetocaloric effect (MCE) has been calculated from the isothermal magnetization data, and the observed anisotropy correlates with H-T phase diagrams. The results are discussed in connection with the magnetic-field induced martensitic-like structural transition observed in the Gd{sub 5}(Si{sub 2}Ge{sub 2})-type compounds.

H. Tang; V.K. Pecharsky; A.O. Pecharsky; D.L. Schlagel; T.A. Lograsso; K.A. Gschneidner,jr.

2004-09-30

76

Determination of quadrupolar spin coupling for spin 7/2 using two pulse sequences  

NASA Astrophysics Data System (ADS)

The response of a spin 7/2 system subject to a first-order quadrupolar interaction and excited by two in-phase pulses separated by time delay is calculated ignoring high frequency terms. The results obtained are valid for any ratio of the quadrupolar coupling to the amplitude of an RF pulse. It is shown here that single- and multiple-quantum coherences developed during the first pulse can be detected at the end of the second pulse. Ot5h 1er pulse sequences with various phase cycling are also discussed. The results are applied to V nuclei in a single ferroelastic crystal of BiVO4.

Ageev, S. Z.; Man, P. P.; Fraissard, J.; Sanctuary, B. C.

77

Magnetic field induced lattice effects in a quasi-two-dimensional organic conductor close to the Mott metal-insulator transition  

NASA Astrophysics Data System (ADS)

We present ultra-high-resolution dilatometric studies in magnetic fields on a quasi-two-dimensional organic conductor ?-(D8-BEDT-TTF)2Cu[N(CN)2]Br, which is located close to the Mott metal-insulator (MI) transition. The obtained thermal expansion coefficient, ?(T), reveals two remarkable features: (i) the Mott MI transition temperature TMI=(13.6±0.6) K is insensitive to fields up to 10 T, the highest applied field; (ii) for fields along the interlayer b axis, a magnetic field induced (FI) phase transition at TFI=(9.5±0.5) K is observed above a threshold field Hc˜1 T, indicative of a spin reorientation with strong magnetoelastic coupling.

de Souza, Mariano; Brühl, Andreas; Strack, Christian; Schweitzer, Dieter; Lang, Michael

2012-08-01

78

Magnetic-field-induced phase transitions in the cerium monochalcogenides CeS and CeSe  

Microsoft Academic Search

Magnetic phase diagrams of CeS and CeSe have studied by neutron scattering, magnetoresistance and magnetization experiments. Along the easy axis [110] the magnetization curve of CeS at 4.2 shows two steps at 5.6 and 9 T. In CeSe at 1.7 K a first-order phase transition occurs at 5.7 T in fields along [110] and [111].

A. Dönni; A. Oyamada; T. Suzuki; K. Sugiyama; M. Date; G. Kido; P. Fischer; A. Furrer; F. Hulliger

1993-01-01

79

Nonclassical correlation in NMR quadrupolar systems  

SciTech Connect

The existence of quantum correlation (as revealed by quantum discord), other than entanglement and its role in quantum-information processing (QIP), is a current subject for discussion. In particular, it has been suggested that this nonclassical correlation may provide computational speedup for some quantum algorithms. In this regard, bulk nuclear magnetic resonance (NMR) has been successfully used as a test bench for many QIP implementations, although it has also been continuously criticized for not presenting entanglement in most of the systems used so far. In this paper, we report a theoretical and experimental study on the dynamics of quantum and classical correlations in an NMR quadrupolar system. We present a method for computing the correlations from experimental NMR deviation-density matrices and show that, given the action of the nuclear-spin environment, the relaxation produces a monotonic time decay in the correlations. Although the experimental realizations were performed in a specific quadrupolar system, the main results presented here can be applied to whichever system uses a deviation-density matrix formalism.

Soares-Pinto, D. O.; Auccaise, R.; Azevedo, E. R. de; Bonagamba, T. J. [Instituto de Fisica de Sao Carlos, Universidade de Sao Paulo, Post Office Box 369, 13560-970 Sao Carlos, Sao Paulo (Brazil); Celeri, L. C.; Maziero, J.; Serra, R. M. [Centro de Ciencias Naturais e Humanas, Universidade Federal do ABC, R. Santa Adelia 166, 09210-170 Santo Andre, Sao Paulo (Brazil); Fanchini, F. F. [Instituto de Fisica Gleb Wataghin, Universidade Estadual de Campinas, Post Office Box 6165, 13083-970 Campinas, Sao Paulo (Brazil)

2010-06-15

80

Electronic disorder and magnetic-field-induced superconductivity enhancement in Fe1+y(Te1-xSex)  

NASA Astrophysics Data System (ADS)

The iron chalcogenide Fe1+y(Te1-xSex) superconductor system exhibits a unique electronic and magnetic phase diagram distinct from those seen in iron pnictides: bulk superconductivity does not appear immediately following the suppression of long-range (?,0) AFM order. Instead, an intermediate phase with weak charge carrier localization appears between AFM order and bulk superconductivity (Liu et al., Nat. Mater. 9, 719 (2010)). In this talk, we report our recent studies on the relationship between the normal state and superconducting properties in Fe1+y(Te1-xSex). We show that the superconducting volume fraction VSC and normal state metallicity significantly increase while the normal state Sommerfeld coefficient ? and Hall coefficient RH drop drastically with increasing Se content in the underdoped superconducting region. Additionally, VSC is surprisingly enhanced by magnetic field in heavily underdoped superconducting samples. The implications of these results will be discussed. Our analyses suggest that the suppression of superconductivity in the underdoped region is associated with electronic disorder caused by incoherent magnetic scattering arising from (?,0) magnetic fluctuations.

Hu, Jin; Liu, Tijiang; Qian, Bin; Mao, Zhiqiang

2012-02-01

81

Orientation control of a synthetic columnar perfluorinated supramolecular dendrimer: Surface anchoring and magnetic-field induced alignments  

NASA Astrophysics Data System (ADS)

Orientation ordering of a synthetic perfluorinated supramolecule containing a hydrophilic core group and perfluorinated tails is strongly affected by the functionality, molecular shape, surface anchoring and magnetic field. Small-angle neutron scattering (SANS), synchrotron X-ray diffraction, polarized light microscopy (PLM) and transmission electron microscopy (TEM) results show that the molecule exhibits hexagonal columnar mesophase upon cooling from isotropic phase. The orientation of the columns was controlled by surface anchoring; the columnar axes were perpendicular to the hydrophobic carbon substrates, while planar alignment is favored on hydrophilic surfaces. Furthermore, the columnar domains align with the magnetic field lines, which is due to diamagnetism of these fan-shaped molecules containing aromatic rings. We show that the magnetic-induced alignment is much effective for the large-scale control of the orientation of the perfluorinated columnar mesophase.

Ki Yoon, Dong; Rim Lee, Su; Ho Kim, Yun; Seong, Baek-Seok; Soo Han, Young; Jung, Hee-Tae

2006-11-01

82

Parallel magnetic field-induced conductance fluctuations in GaAs/AlGaAs ballistic quantum dots.  

NASA Astrophysics Data System (ADS)

We present magnetotransport measurements in ballistic quantum dots under a parallel magnetic field. The dots were fabricated on two different GaAs/AlGaAs quantum wells with thicknesses of 15 and and 45 nm and with one and two subbands occupied, respectively. The samples were patterned using e-beam lithography and wet etching. A Cr/Au electrostatic top gate was used in order to tune the width of the dot openings. The measurements were performed down to 300 mK with the magnetic field applied strictly parallel to the plane of the two-dimensional electron gas. For both dots, we observe universal conductance fluctuations and, in the case of the wide quantum well, a reduction of their amplitude at large magnetic field. We discuss these conductance fluctuations in terms of orbital effect(V.I. Fal'ko and T. Jungwirth, Phys Rev B 65), 081306 (2002) and magnetic subband depopulation.

Faniel, S.; Gustin, C.; Melinte, S.; Hackens, B.; Bayot, V.; Shayegan, M.

2004-03-01

83

Stress-assisted large magnetic-field-induced strain in single-variant Co-Ni-Ga ferromagnetic shape memory alloy.  

PubMed

The magnetic anisotropy and the magnetic-field-induced strain (MFIS) in a single-variant Co(47.5)Ni(22.5)Ga(30.0) ferromagnetic shape memory alloy (FSMA) have been investigated. From the magnetization curves for the single crystal, the hard c-axis was confirmed, and the uniaxial magnetic anisotropy constant K(u) at 300 K was evaluated to be -1.07 × 10(6) erg cm(-3) for the single-variant Co(47.5)Ni(22.5)Ga(30.0) martensite phase. The magnitude of compressive shear stress for the variant rearrangement was estimated to be 6.0-7.5 MPa from the stress-strain curves. An assisted stress ?(assist) of 6.0 MPa was applied before applying a magnetic field, and then a magnetic stress ?(mag) of 0.3 MPa was added. As a result, a large MFIS of about 7.6 % was obtained at room temperature in the martensite phase of the single-variant Co(47.5)Ni(22.5)Ga(30.0). PMID:21828446

Morito, H; Oikawa, K; Fujita, A; Fukamichi, K; Kainuma, R; Ishida, K

2009-06-01

84

dc- and ac-magnetic field-induced strain effects in ferromagnetic shape memory composites of Ni-Mn-Ga single crystal and polyurethane polymer  

NASA Astrophysics Data System (ADS)

Ferromagnetic shape memory composites of multilayer and sandwich types were fabricated by laminating Ni-Mn-Ga single-crystal plates with polyurethane (PU) polymer plates. The dc- and ac-magnetic field-induced strains (MFISs) in the composites were measured as functions of both magnetic field and mechanical load, and the results were compared with those of the single crystal. It was found that the load-free dc-MFISs were 5.6%, 1.5%, and 0.8%, while the load-free ac-MFISs were 0.3%, 0.8%, and 0.5% in the single crystal, multilayer composite, and sandwich composite, respectively. The relatively smaller load-free dc-MFISs and larger load-free ac-MFISs in the composites than the single crystal originated from the stress bias of the Ni-Mn-Ga plates by the PU plates in the composites. The dc-MFISs of all samples and the ac-MFISs of the composites decreased with the increase in mechanical load amplitude, while the ac-MFIS of the single crystal peaked at 1.6 MPa load.

Zeng, Min; Or, Siu Wing; Chan, Helen Lai Wa

2010-05-01

85

Quadrupolar particles in a nematic liquid crystal: Effects of particle size and shape  

Microsoft Academic Search

We investigate the effects of particle size and shape on the quadrupolar (Saturn-ring-like) defect structures formed by a nematic liquid crystal around nm-sized and mum -sized particles with spherical and spherocylindrical shapes. We also report results for the potentials of mean force in our systems, calculated using a mesoscale theory for the tensor order parameter Q of the nematic. Our

Francisco R. Hung

2009-01-01

86

Quadrupolar particles in a nematic liquid crystal: Effects of particle size and shape  

Microsoft Academic Search

We investigate the effects of particle size and shape on the quadrupolar (Saturn ring-like) defect structures formed by a nematic liquid crystal (NLC) around nm- and micron-sized particles with spherical, spherocylindrical and cubic shapes. Our calculations, based on a Landau-de Gennes expansion in terms of the tensor order parameter Q, indicate that for pairs of nanoparticles in close proximity, the

Francisco R. Hung

2009-01-01

87

Origin of the magnetic field induced changes of the transverse plasma mode in the c-axis infrared response of underdoped YBa2Cu3O(7-?).  

PubMed

We report on results of our theoretical study of magnetic field induced changes of the c-axis infrared response of bilayer cuprate superconductors using the phenomenological multilayer model involving the conductivity of the spacing layers and that of the bilayer units. For H perpendicular to the planes, the local conductivities have been expressed in terms of a two-fluid approximation--as weighted averages of the superconducting state ones and the normal state ones representing contributions of the vortex cores, the weight of the latter increasing linearly with the field. This allows us to reproduce and interpret the fast decrease with increasing H of the well known 400 cm(-1) peak (transverse plasma mode) in the c-axis conductivity, observed by LaForge and co-workers. For the local conductivities of underdoped YBa(2)Cu(3)O(7-?) with T(c)=58 K reported by Dubroka and co-workers and the fraction of the normal state (T ? T(c)) component given by (?(0)H/25 T), the computed field induced changes of the reflectivity are in quantitative agreement with the data. This suggests that the response at H=0 and T ? T(c) is close to that at H=25 T < H(c2) and T ? T(c), in accord with theories attributing the above T(c) state to that of a superconductor lacking long-range phase coherence. Also discussed are changes of the response induced by H parallel to the CuO(2) planes. PMID:21951994

Marek, J; Munzar, D

2011-09-27

88

Magnetic-field-induced localization in narrow-gap semiconductors Hg/sub 1-//sub x/Cd/sub x/Te and InSb  

SciTech Connect

Magnetotransport measurements on n-type Hg/sub 1-//sub x/Cd/sub x/Te (xapprox. =0.2) and InSb and far-infrared magnetooptical spectroscopy in Hg/sub 1-//sub x/Cd/sub x/Te are reported. The transport data at magnetic fields below and near the magnetic-field-induced metal-insulator (M-I) transition indicate clear similarity of Hg/sub 1-//sub x/Cd/sub x/Te and InSb. At fields well above the M-I transition and at low temperatures, the magnetotransport coefficients for Hg/sub 1-//sub x/Cd/sub x/Te show anomalously weak dependences on field and temperature. This is attributed to shorting of the bulk by a conducting surface layer. Below the M-I transition field, an anomalous Hall effect is observed in both Hg/sub 1-//sub x/Cd/sub x/Te and InSb. We interpret this effect within a model in which the M-I transition takes place in the donor impurity band. The impurity cyclotron resonance observed in Hg/sub 1-//sub x/Cd/sub x/Te provides conclusive evidence for donor-bound electrons in this semiconductor and further confirms its similarity to InSb. The cyclotron-resonance data are in agreement with theoretical predictions for hydrogenic donors in a strong magnetic field. These observations provide strong evidence against the Wigner crystallization of electrons in Hg/sub 1-//sub x/Cd/sub x/Te.

Shayegan, M.; Goldman, V.J.; Drew, H.D.

1988-09-15

89

Relaxation times of spin states of all ranks and orders of quadrupolar nuclei estimated from NMR z-spectra: Markov chain Monte Carlo analysis applied to 7Li+ and 23Na+ in stretched hydrogels.  

PubMed

The NMR z-spectra of 7Li+ and 23Na+ in stretched hydrogels contain five minima, or critical values, with a sharp "dagger" on the central dip. The mathematical representation of such z-spectra from spin-3/2 nuclei contains nine distinct (the total is 15 but there is redundancy of the ±order-numbers) relaxation rate constants that are unique for each of the spin states, up to rank 3, order 3. We present an approach to multiple-parameter-value estimation that exploits the high level of separability of the effects of each of the relaxation rate constants on the features of the z-spectrum. The Markov chain Monte Carlo (MCMC) method is computationally demanding but it yielded statistically robust estimates (low coefficients of variation) of the parameter values. We describe the implementation of the MCMC analysis (in the present context) and posit that it can obviate the need for using multiple-quantum filtered RF-pulse sequences to estimate all relaxation rate constants/times under experimentally favorable, but readily achievable, circumstances. PMID:21742525

Kuchel, Philip W; Naumann, Christoph; Puckeridge, Max; Chapman, Bogdan E; Szekely, David

2011-06-14

90

Gas Phase Xenon131 Quadrupolar Splitting at High Magnetic Fields  

Microsoft Academic Search

At very high magnetic fields strengths (14 Tesla and higher) the xenon-131 gas phase NMR spectrum shows a well resolved quadrupolar splitting. Quadrupolar coupling between a non-spherical (S>1\\/2) nuclei and an electric field gradient will occur when the electrical isotropy of the surrounding electron cloud is disturbed. The experimental results suggest that the origin of the observed splitting in the

Thomas Meersmann

1998-01-01

91

Fundamental measure density functional theory study of liquid-vapor interface of dipolar and quadrupolar fluids  

NASA Astrophysics Data System (ADS)

We have studied interfacial structure and properties of liquid-vapor interfaces of dipolar fluids and quadrupolar fluids, respectively, using the classical density functional theory (DFT). Towards this end, we employ the fundamental measure DFT for a reference hard-sphere (HS) part of free energy and the modified mean field approximation for the correlation function of dipolar or quadrupolar fluid. At low temperatures we find that both the liquid-vapor interfacial density profile and orientational order parameter profile exhibit weakly damped oscillatory decay into the bulk liquid. At high temperatures the decay of interfacial density and order parameter profiles is entirely monotonic. The scaled temperature ? = 1 - T/Tc that separates the two qualitatively different interfacial structures is in the range 0.10-0.15. At a given (dimensionless) temperature, increasing the dipolar or quadrupolar moment enhances the density oscillations. Application of an electric field (normal to the interface) will damp the oscillations. Likewise, at the given temperature, increasing the strength of any multipolar moment also increases the surface tensions while increasing the strength of the applied electric field will reduce the surface tensions. The results are compared with those based on the local-density approximations (LDA) for the reference HS part of free energy as well as with results of numerical experiments.

Warshavsky, V. B.; Zeng, X. C.

2013-10-01

92

Possible observation of quadrupolar Kondo effect in Pr-based dilute quadrupolar compounds  

NASA Astrophysics Data System (ADS)

We have studied the low-temperature properties of PrLa1-xPb3 andPrLa1-xlnAg2 with the crystal-electric-field (CEF) ground state of a non-Kramers ?3 doublet. In PrLa1-xPb3, non-Fermi-liquid (NFL) behavior has been observed for Pr concentrations x?0.05 in the specific heat C/T, susceptibility and electrical resistivity at low temperatures. Moreover, application of magnetic field raises C/T rapidly, which demonstrates the presence of the residual entropy at lower temperatures. InPrLa1-xlnAg2, characteristic features have been seen up to x=0.8 in the susceptibility and specific heat below 15 K. These behaviors can be caused by the quadrupolar Kondo effect arising from the correlation between the dilute ?3 moments and the conduction electrons.

Kawae, T.; Nakaie, Y.; Inagaki, Y.; Hidaka, M.; Tateiwa, N.; Kitai, T.

2007-03-01

93

Kn 26, a new quadrupolar planetary nebula  

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

94

Susceptibility formalism for magnetic and quadrupolar interactions in hexagonal and tetragonal rare-earth compounds  

Microsoft Academic Search

A susceptibility formalism is developed for analyzing the magnetic and quadrupolar interactions in hexagonal and tetragonal rare-earth compounds. Symmetrized expressions are given for the one-ion magnetoelastic coupling and for the two-ion quadrupolar interactions. This formalism, derived from perturbation theory, leads to specific magnetic, strain, and quadrupolar susceptibilities considering both the crystalline-electric-field effects and quadrupolar interactions. It allows an analytical description

P. Morin; J. Rouchy; D. Schmitt

1988-01-01

95

Dominant biaxial quadrupolar contribution to the nematic potential of mean torque  

NASA Astrophysics Data System (ADS)

Within the general quadrupolar model for biaxial nematic liquid crystals, whose potential of mean torque extends that in the Maier-Saupe theory with two extra interaction terms, we propose a quantitative criterion to identify the dominant biaxial interaction. We show that the ratio of the biaxial-to-uniaxial and uniaxial-to-isotropic transition temperatures is almost independent of one interaction parameter, thus indicating the other as dominant. We also show that there is a significant mismatch between the principal orientational order parameters predicted by the theory and those measured for the biaxial phase of a tetrapode.

Bisi, Fulvio; Luckhurst, Geoffrey R.; Virga, Epifanio G.

2008-08-01

96

Dominant biaxial quadrupolar contribution to the nematic potential of mean torque.  

PubMed

Within the general quadrupolar model for biaxial nematic liquid crystals, whose potential of mean torque extends that in the Maier-Saupe theory with two extra interaction terms, we propose a quantitative criterion to identify the dominant biaxial interaction. We show that the ratio of the biaxial-to-uniaxial and uniaxial-to-isotropic transition temperatures is almost independent of one interaction parameter, thus indicating the other as dominant. We also show that there is a significant mismatch between the principal orientational order parameters predicted by the theory and those measured for the biaxial phase of a tetrapode. PMID:18850855

Bisi, Fulvio; Luckhurst, Geoffrey R; Virga, Epifanio G

2008-08-26

97

Quadrupolar, Triple [Delta]-Function Potential in One Dimension  

ERIC Educational Resources Information Center

|The energy and parity eigenstates for quadrupolar, triple [delta]-function potential are analysed. Using the analytical solutions in specific domains, simple expressions are obtained for even- and odd-parity bound-state energies. The Heisenberg uncertainty product is observed to have a minimum for a specific strength of the potential. The…

Patil, S. H.

2009-01-01

98

Quadrupolar second-harmonic generation by helical beams and vectorial vortices with radial or azimuthal polarization  

NASA Astrophysics Data System (ADS)

We study the optical second-harmonic radiation (SHG) generated by scattering from a homogeneous centrosymmetric thin composite material illuminated by higher-order Gaussian laser beams. The induced second-order source polarization is taken as of quadrupolar type (E·?)E, which depends on the inhomogeneity of the incident electric field E. This nonlinear source has the same form as that responsible of the SH signal observed in a composite made of Si nanocrystals embedded uniformly in a SiO2 matrix and that calculated for a thin disordered array of nanospheres. We calculate the SH radiation angular patterns generated by several incident combinations of spatial modes and states of polarizations. In particular, excitation with radially and azimuthally polarized doughnut modes and helical beams carrying orbital angular momentum with linear or circular polarization are considered. We found that this quadrupolar SHG depends sensitively on the transverse structure and polarization of the driving field. The response to ?E introduces a factor E(E·K) in the Fourier component of the SH scattering amplitude, absent in electric-dipole-allowed SHG, that can give additional nodal lines or rings in the SH angular patterns, changes of the state of polarization, or additional azimuthal phases in the harmonic radiation. For circularly polarized beams with helical phase wave front, we found a selection rule according to which the nonlinear scattering of an optical vortex with charge l? and spin ?=±1 induces a SH vortex field with a spin-dependent charge doubling l2?=2l?+?. These features may be useful to identify SHG processes of quadrupolar nature and suggest a way to produce scattered SH radiation with a desired angular pattern and state of polarization.

Mandujano, Miguel G.; Maytorena, Jesús A.

2013-08-01

99

The combined effect of quadrupolar and dipolar interactions on the excitation and evolution of triple quantum coherences in ?Li solid state magic angle spinning NMR.  

PubMed

Magic-angle spinning triple-quantum NMR spectra of lithium-7 provide enhanced spectral dispersion for the inherent low chemical shift range of this nucleus, while maintaining linewidths, which are free of any quadrupolar broadening to first order. Since the quadrupolar interaction of (7)Li is very small, in the order of the radio frequency nutation frequencies and only moderately larger than the spinning rates, such spectra are also only marginally affected by the second order quadrupolar interaction under large magnetic fields. In the current study we demonstrate that the existence of two and more proximate (7)Li spins, as encountered in many materials, affects both excitation and evolution of triple-quantum coherences due to the combined effect of quadrupolar and homonuclear dipolar interactions. We show that the generation of (7)Li triple-quantum coherences using two ?/2 pulses separated by one-half rotor period is superior in such cases to a single pulse excitation since the excitation time is shorter; thus the maximum signal is only marginally affected by the homonuclear dipolar couplings. When the quadrupolar-dipolar cross terms dominate the spectra, single- and triple-quantum lineshapes are very similar and therefore a true gain in dispersion is maintained in the latter spectrum. The effects of quadrupolar-dipolar cross terms are experimentally demonstrated by comparing a natural abundance and a (6)Li-diluted samples of lithium acetate, resulting in the possibility of efficient excitation of triple quantum coherences over longer periods of time, and in longer life times of triple-quantum coherences. PMID:23481861

Eliav, Uzi; Goldbourt, Amir

2013-02-09

100

Low temperature transport properties of the quadrupolar Kondo lattice system PrTi2Al20  

NASA Astrophysics Data System (ADS)

We have investigated the low temperature transport properties of the cubic ?3 compound PrTi2Al20. This is a quadrupolar Kondo lattice system where the nongmagnetic quadrupoles, which form a long-range order at low temperatures, have strong hybridization with the conduction electrons. A sharp drop of the resistivity due to a ferroquadrupole ordering is observed at T Q = 2.0 K. The T 2 dependence of the resistivity and the large Sommerfeld coefficient ? above T Q suggest the formation of a heavy-fermion state. The temperature dependence of the resistivity below T Q does not show a power law but exponential law behavior, indicating the emergence of an anisotropy gap ? in the collective mode associated with the ferroquadrupole order below T Q. The Fisher-Langer relation holds around T Q, suggesting the higher order scattering processes than those in Born approximation are not dominant for this ferroquadrupole ordering.

Sakai, Akito; Nakatsuji, Satoru

2013-08-01

101

Highly efficient multiphoton-absorbing quadrupolar oligomers for frequency upconversion.  

PubMed

Two series of quadrupolar diphenylamino-endcapped oligofluorenes, PhN-OF(n)-NPh (n=2-5) and PhN-OF(n)-TAZ-OF(n)-NPh (n=1-4), which have an electron-withdrawing 1,2,4-triazole (TAZ) moiety as central core, with D-?-A-?-D structural motif (D=donor, A=acceptor), have been synthesized by palladium-catalyzed Suzuki cross-coupling of 9,9-dibutyl-7-(diphenylamino)-2-fluorenylboronic acid and the corresponding (1,2,4-triazole-based) aryl halide as key step. On pumping with infrared femtosecond lasers, these oligomers showed very strong multiphoton-excited blue photoluminescence. These D-?-D and D-?-A-?-D quadrupolar oligofluorenes exhibit superior three-photon absorption properties compared to the respective D-?-A counterparts with a highest three-photon absorption cross-section (?(3)) of up to 2.72×10(-77) cm(6) s(2) . Despite the comparable linear and multiphoton absorption properties of the two types of quadrupolar oligomers PhN-OF(n)-NPh and PhN-OF(n)-TAZ-OF(n)-NPh, only the former exhibit remarkably intense and highly efficient multiphoton-excited frequency-upconverted deep blue lasing, which gives rise to record high lasing efficiency of 0.097% and very narrow of full width at half-maximum of the lasing spectra. Our findings suggest that quadrupolar-type molecules/oligomers are superior for multiphoton excited frequency upconverted lasing to their dipolar counterparts and also provide important guidelines to design highly efficient three-photon absorption molecules for photoluminescence and lasing applications. PMID:21264964

Feng, Xin Jiang; Wu, Po Lam; Li, King Fai; Wong, Man Shing; Cheah, Kok Wai

2011-01-24

102

Two-dimensional nuclear magnetic resonance of quadrupolar systems  

SciTech Connect

This dissertation describes two-dimensional nuclear magnetic resonance theory and experiments which have been developed to study quadruples in the solid state. The technique of multiple-quantum magic-angle spinning (MQMAS) is extensively reviewed and expanded upon in this thesis. Specifically, MQMAS is first compared with another technique, dynamic-angle spinning (DAS). The similarity between the two techniques allows us to extend much of the DAS work to the MQMAS case. Application of MQMAS to a series of aluminum containing materials is then presented. The superior resolution enhancement through MQMAS is exploited to detect the five- and six-coordinated aluminum in many aluminosilicate glasses. Combining the MQMAS method with other experiments, such as HETCOR, greatly expands the possibility of the use of MQMAS to study a large range of problems and is demonstrated in Chapter 5. Finally, the technique switching-angle spinning (SAS) is applied to quadrupolar nuclei to fully characterize a quadrupolar spin system in which all of the 8 NMR parameters are accurately determined. This dissertation is meant to demonstrate that with the combination of two-dimensional NMR concepts and new advanced spinning technologies, a series of multiple-dimensional NMR techniques can be designed to allow a detailed study of quadrupolar nuclei in the solid state.

Wang, Shuanhu

1997-09-17

103

Enhanced solid-state NMR correlation spectroscopy of quadrupolar nuclei using dynamic nuclear polarization.  

PubMed

By means of a true sensitivity enhancement for a solid-state NMR spectroscopy (SSNMR) experiment performed under dynamic nuclear polarization (DNP) conditions, corresponding to 4-5 orders of magnitude of time savings compared with a conventional SSNMR experiment, it is shown that it is possible to record interface-selective (27)Al-(27)Al two-dimensional dipolar correlation spectra on mesoporous alumina, an advanced material with potential industrial applications. The low efficiency of cross-polarization and dipolar recoupling for quadrupolar nuclei is completely negated using this technique. The important presence of pentacoordinated Al has not only been observed, but its role in bridging interfacial tetra- and hexacoordinated Al has been determined. Such structural information, collected at low temperature (?103 K) and 9.4 T with the use of DNP, would have been impossible to obtain under standard conditions, even using a higher magnetic field. However, here it is demonstrated that this information can be obtained in only 4 h. This work clearly opens a new avenue for the application of SSNMR to quadrupolar nuclei and notably the atomic-scale structure determination of catalysis materials such as mesoporous alumina. PMID:23095121

Lee, Daniel; Takahashi, Hiroki; Thankamony, Aany S L; Dacquin, Jean-Philippe; Bardet, Michel; Lafon, Olivier; Paëpe, Gaël De

2012-11-02

104

Pair-breaking effect caused by the anion disorder in the magnetic-field-induced spin-density wave: A calorimetric study  

Microsoft Academic Search

We have investigated the effect of anion disorder on the spin-density wave induced by the magnetic field (FISDW) in (TMTSF)2ClO4 (the TMTSF is the tetramethyltetraselenafulvalene molecule). Specific heat and magnetocaloric-effect measurements have been performed under a magnetic field for various cooling rates across the ordering transition of the ClO4 anions. The respective variations of the critical temperature and of the

F. Tsobnang; F. Pesty; P. Garoche

1994-01-01

105

The effect of pressure on the phase diagram of the magnetic field-induced superconducting state of ? -(BETS){2}FeCl{4}  

NASA Astrophysics Data System (ADS)

We report the effect of a small hydrostatic pressure p \\cong 1.4 kBar on the temperature-magnetic field phase diagram of the organic conductor ? -(BETS){2}FeCl{4}. At zero field a first-order superconducting (TC \\cong 5.6 K) to antiferromagnetic insulator transition (TN \\cong 4 K) is observed. The close proximity between both phases is suggestive of an unconventional superconducting pairing mechanism. Furthermore, the transition temperature towards the field-induced superconducting state (FISC), as well as its concomitant upper critical field, is found to increase by a factor of ˜ 33 %. The phase diagram of the FISC state for both p = 1 Bar and 1.4 kBar are well described in terms of the Jaccarino-Peter effect if the quasiparticle nature of the charge carriers is taken into account. Key words. Organic conductors magnetism superconductivity.

Balicas, L.; Barzykin, V.; Storr, K.; Brooks, J. S.; Tokumoto, M.; Uji, S.; Tanaka, H.; Kobayashi, H.; Kobayashi, A.

2004-04-01

106

Magnetic field-induced increase in chlorophyll a delayed fluorescence of photosystem II: A 100- to 200-ns component between 4.2 and 300 K  

PubMed Central

At room temperature the delayed fluorescence (luminescence) of spinach chloroplasts, in which the acceptor Q is prereduced, consists of a component with a lifetime of 0.7 ?s and a more rapid component, presumably with a lifetime of 100-200 ns and about the same integrated intensity as the 0.7- ?s component. Between 4.2 and 200 K only a 100- to 200-ns luminescence component was found, with an integrated intensity appreciably larger than that at room temperature. At 77 K the 150-ns component approached 63% of saturation at roughly the same energy as the variable fluorescence of photosystem II at room temperature. At 77 K the emission spectra of prompt fluorescence but not that of the 150-ns luminescence had a preponderant additional band at about 735 nm. The 150-ns emission also occurred in the photosystem I-lacking mutant FL5 of Chlamydomonas. These experiments indicate that the 150-ns component originates from photosystem II. At room temperature a magnetic field of 0.22 T stimulated the 0.7-?s delayed fluorescence by about 10%. At 77 K the field-induced increase of the 150-ns component amounted to 40-50%, being responsible for the observed ?2% increase of the total emission; the magnetic field increased the lifetime about 20%. In order to explain these phenomena a scheme for photosystem II is presented with an intermediary acceptor W between Q and the primary donor chlorophyll P-680; recombination of P-680+ and W- causes the fast luminescence. The magnetic field effect on this emission is discussed in terms of the radical pair mechanism.

Sonneveld, Arie; Duysens, Louis N. M.; Moerdijk, Adri

1980-01-01

107

2H2O quadrupolar splitting used to measure water exchange in erythrocytes  

NASA Astrophysics Data System (ADS)

The 2H NMR resonance from HDO (D = 2H) in human red blood cells (RBCs) suspended in gelatin that was held stretched in a special apparatus was distinct from the two signals that were symmetrically arranged on either side of it, which were assigned to extracellular HDO. The large extracellular splitting is due to the interaction of the electric quadrupole moment of the 2H nuclei with the electric field gradient tensor of the stretched, partially aligned gelatin. Lack of resolved splitting of the intracellular resonance indicated greatly diminished or absent ordering of the HDO inside RBCs. The separate resonances enabled the application of a saturation transfer method to estimate the rate constants of transmembrane exchange of water in RBCs. However both the theory and the practical applications needed modifications because even in the absence of RBCs the HDO resonances were maximally suppressed when the saturating radio-frequency radiation was applied exactly at the central frequency between the two resonances of the quadrupolar HDO doublet. More statistically robust estimates of the exchange rate constants were obtained by applying two-dimensional exchange spectroscopy (2D EXSY), with back-transformation analysis. A monotonic dependence of the estimates of the efflux rate constants on the mixing time, tmix, used in the 2D EXSY experiment were seen. Extrapolation to tmix = 0, gave an estimate of the efflux rate constant at 15 °C of 31.5 ± 2.2 s-1 while at 25 °C it was ˜50 s-1. These values are close to, but less than, those estimated by an NMR relaxation-enhancement method that uses Mn2+ doping of the extracellular medium. The basis for this difference is thought to include the high viscosity of the extracellular gel. At the abstract level of quantum mechanics we have used the quadrupolar Hamiltonian to provide chemical shift separation between signals from spin populations across cell membranes; this is the first time, to our knowledge, that this has been achieved.

Kuchel, Philip W.; Naumann, Christoph

2008-05-01

108

Quadrupolar Effect on Two Layered Thin Film Antiferroelectric Smectic Liquid Crystal  

SciTech Connect

Within the framework of the discrete Landau phenomenological model, the free energy of an antiferroelectric smectic liquid crystal is analyzed. This model considers the interactions between the liquid crystal molecules within the nearest and the next nearest layers. Electrostatic quadrupolar interaction up to the nearest layers is included. This quadrupolar term, b{sub q{xi}}???{sub i{center_dot}{xi}}???{sub i+1}{sup 2} is positive, thus favouring a perpendicular orientation in the adjacent layer respectively. We show how quadrupolar interaction can affects the planar regions of the phase diagram of a two layered thin antiferroelectric smectic liquid crystal film.

Lum, Chia-Yuee; Ong, Lye-Hock [School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Cepic, Mojca [Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia, Faculty of Education, University of Ljubljana, Kardeljeva pl. 16. 1000 Ljubljana (Slovenia)

2011-03-30

109

Magnetic and quadrupolar phase transitions in cubic rare-earth intermetallic compounds  

Microsoft Academic Search

A new analytical approach of the problem of magnetic and quadrupolar phase transitions in rare-earth intermetallic compounds is presented, in terms of single-ion susceptibilities and within the Landau theory: The coefficients of the free-energy expansion are simply related to several magnetic, strain, and quadrupolar crystal-field susceptibilities, the expression of which is given for any multilevel system. The analysis of sign

P. Morin; D. Schmitt

1983-01-01

110

Quantum logical operations for spin 3\\/2 quadrupolar nuclei monitored by quantum state tomography  

Microsoft Academic Search

This article presents the realization of many self-reversible quantum logic gates using two-qubit quadrupolar spin 3\\/2 systems. Such operations are theoretically described using propagation matrices for the RF pulses that include the effect of the quadrupolar evolution during the pulses. Experimental demonstrations are performed using a generalized form of the recently developed method for quantum state tomography in spin 3\\/2

F. A. Bonk; E. R. Deazevedo; R. S. Sarthour; J. D. Bulnes; J. C. C. Freitas; A. P. Guimarães; I. S. Oliveira; T. J. Bonagamba

2005-01-01

111

Evidence of quadrupolar scattering in the anisotropic electrical magnetoresistivity of PrNi sub 5  

SciTech Connect

The temperature and magnetic-field dependences of the electrical resistivity measured on a single crystal of the Van Vleck paramagnetic PrNi{sub 5} exhibit an anisotropic behavior. The influence of the spin-disorder scattering as well as the quadrupolar scattering of conduction electrons by the 4{ital f} shell must be taken into account to explain the experimental results. In particular, a quadrupolar contribution plays an important role in the observed anisotropy.

Blanco, J.A. (Laboratoire Louis Neel, CNRS, 166X, 38042 Grenoble CEDEX (France)); Reiffers, M. (Institute of Experimental Physics, Slovakian Academy of Sciences, 04353 Kosice (Czechoslovakia)); Gignoux, D.; Schmitt, D. (Laboratoire Louis Neel, CNRS, 166X, 38042 Grenoble CEDEX (France)); Jansen, A.G.M. (Max-Plank-Institut fuer Festkoerperforschung Hochfeld-Magnetlabor, 166X, 38042 Grenoble CEDEX (France))

1991-11-01

112

Combining dipolar-quadrupolar correlation spectroscopy with isotropic shift resolution in magic-angle-spinning 17O NMR.  

PubMed

We explore the effect of heteronuclear dipolar recoupling on the satellite and multiple-quantum transitions of a half-integer-spin quadrupolar nucleus coupled to a single spin-12. A three-dimensional experiment is introduced that resolves different quadrupolar sites whilst allowing simultaneous extraction of the quadrupolar coupling constants, asymmetry parameters of the electric field gradient, and the isotropic shifts of the quadrupolar nucleus. The experiment also enables estimation of the heteronuclear dipolar coupling constant between the spin-1/2 and half-integer spin quadrupolar nucleus. The relative orientation of the dipolar tensor with respect to the quadrupolar tensor can be estimated by comparing experiments and simulations. Experimental results are shown on a sample of brucite, Mg((17)OH)(2), where the (1)H-(17)O bond distance is estimated. PMID:22595292

Goswami, M; Madhu, P K

2012-04-10

113

Detailed analysis of the S-RESPDOR solid-state NMR method for inter-nuclear distance measurement between spin-1/2 and quadrupolar nuclei  

NASA Astrophysics Data System (ADS)

We present a detailed analysis of the Symmetry-based Resonance-Echo Saturation-Pulse DOuble-Resonance (S-RESPDOR) method in order to measure the inter-nuclear distances between spin-1/2 and quadrupolar nuclei. This recently introduced sequence employs a symmetry-based recoupling scheme on the observed spin-1/2 channel and a saturation pulse on the quadrupolar channel. This method requires a low radio-frequency (rf) field, is compatible with high MAS frequency and allows a rapid determination of inter-nuclear distances by fitting the experimental signal fraction to an analytical expression. Here, we analyze in detail the influence of the various experimental and spin-interaction parameters on the S-RESPDOR signal fraction and the measured distance. We show that the S-RESPDOR signal fraction only depends on the quadrupole interaction and the inter-nuclear distance. We demonstrate that the required rf-field on the quadrupolar channel is smaller than that required for an adiabatic-passage pulse in REAPDOR-type experiments. The only limitation of the method is the requirement of accurate rotor synchronization between the two parts of the dipolar recoupling sequences. Using S-RESPDOR, we have quantitatively measured a 31P-51V distance of 357 pm in a mono-vanadium-substituted polyoxo-tungstate, K4PVW11O40, from the Keggin family and a 13C-67Zn distance of 286 pm in [80%-67Zn]zinc [1 - 13C]acetate. These results show that S-RESPDOR can be employed in the challenging cases of quadrupolar nuclei exhibiting a high spin number and either large chemical-shift anisotropy (51V) or low gyromagnetic ratio (67Zn).

Lu, Xingyu; Lafon, Olivier; Trébosc, Julien; Amoureux, Jean-Paul

2012-02-01

114

Differential Line Broadening in the Presence of Quadrupolar-CSA Interference  

NASA Astrophysics Data System (ADS)

The formalism for calculating the lineshape of a spin 1/2J-coupled to a high-spin nucleus undergoing quadrupolar and chemical shift anisotropy (CSA) relaxations is derived in the case where the tensors of both interactions are noncoincident and nonaxial. The expressions show that the CSA-quadrupolar interference term which is responsible for the asymmetry of lines involves a term depending on tensorial parameters. The effect of this term on the lineshapes is discussed with respect to three cases, namely coincident-axially symmetric, noncoincident-axially symmetric, and general noncoincident quadrupolar and CSA tensors. These cases are considered in the analysis of the lineshape of the1H-decoupled spectra of the31P nucleusJ-coupled to the59Co nucleus encountered in the tetrahedral cluster HFeCo3(CO)11PPh2H.

Elbayed, Karim; Kempgens, Pierre; Raya, Jésus; Granger, Pierre; Rosé, Jacky

1998-02-01

115

NMR quadrupolar system described as Bose-Einstein-condensate-like system  

NASA Astrophysics Data System (ADS)

This paper presents a description of nuclear magnetic resonance (NMR) of quadrupolar systems using the Holstein-Primakoff (HP) formalism and its analogy with a Bose-Einstein condensate (BEC) system. Two nuclear spin systems constituted of quadrupolar nuclei I=3/2 (23Na) and I=7/2 (133Cs) in lyotropic liquid crystals were used for experimental demonstrations. Specifically, we derived the conditions necessary for accomplishing the analogy, executed the proper experiments, and compared with quantum mechanical prediction for a Bose system. The NMR description in the HP representation could be applied in the future as a workbench for BEC-like systems, where the statistical properties may be obtained using the intermediate statistic, first established by Gentile. The description can be applied for any quadrupolar systems, including new developed solid-state NMR GaAS nanodevices.

Auccaise, R.; Teles, J.; Bonagamba, T. J.; Oliveira, I. S.; Deazevedo, E. R.; Sarthour, R. S.

2009-04-01

116

FAST TRACK COMMUNICATION: Antiferro-quadrupolar structures in UPd3 inferred from x-ray resonant Bragg diffraction  

NASA Astrophysics Data System (ADS)

A systematic analysis of resonant x-ray Bragg diffraction data for UPd3, with signal enhancement at the U MIV edge, including possible structural phase transitions leads to a new determination of the space groups of the material in the phases between T0 = 7.8 K and T+1 = 6.9 K, as P 2221, and between T-1 = 6.7 K and T2 = 4.4 K, as P 21. In addition, the quadrupolar order parameters, langQabrang, inferred from diffraction data for the phase between T-1 and T2, are langQxzrang and langQyzrang at the (103) Bragg reflection and langQxyrang at the (104) reflection.

Fernández-Rodríguez, Javier; Lovesey, Stephen W.; Blanco, Jesús A.

2010-01-01

117

Quadrupolar spectra of nuclear spins in strained InxGa1-xAs quantum dots  

NASA Astrophysics Data System (ADS)

Self-assembled quantum dots (QDs) are born out of lattice mismatched ingredients where strain plays an indispensable role. Through the electric quadrupolar coupling, strain affects the magnetic environment as seen by the nuclear spins. To guide prospective single-QD nuclear magnetic resonance (NMR), as well as dynamic nuclear spin polarization experiments, an atomistic insight to the strain and quadrupolar field distributions is presented. A number of implications of the structural and compositional profile of the QD have been identified. A high aspect ratio of the QD geometry enhances the quadrupolar interaction. The inclined interfaces introduce biaxiality and the tilting of the major quadrupolar principal axis away from the growth axis; the alloy mixing of gallium into the QD enhances both of these features while reducing the quadrupolar energy. Regarding the NMR spectra, both Faraday and Voigt geometries are investigated, unraveling in the first place the extend of inhomogeneous broadening and the appearance of the normally forbidden transitions. Moreover, it is shown that from the main extend of the NMR spectra the alloy mole fraction of a single QD can be inferred. By means of the element-resolved NMR intensities it is found that In nuclei has a factor of 5 dominance over those of As. In the presence of an external magnetic field, the borderlines between the quadrupolar and Zeeman regimes are extracted as 1.5 T for In and 1.1 T for As nuclei. At these values the nuclear spin depolarization rates of the respective nuclei get maximized due to the noncollinear secular hyperfine interaction with a resident electron in the QD.

Bulutay, Ceyhun

2012-03-01

118

Conformational response of the phosphatidylcholine headgroup to bilayer surface charge: torsion angle constraints from dipolar and quadrupolar couplings in bicelles.  

PubMed

The effects of bilayer surface charge on the conformation of the phosphocholine group of phosphatidylcholine were investigated using a torsion angle analysis of quadrupolar and dipolar splittings in, respectively, (2)H and (13)C NMR spectra of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) labelled in the phosphocholine group with either deuterons (POPC-alpha-d(2), POPC-beta-d(2) and POPC-gamma-d(9)) or carbon-13 (POPC-alpha-(13)C and POPC-alphabeta-(13)C(2)) and incorporated into magnetically aligned bicelles containing various amounts of either the cationic amphiphile 1,2-dimyristoyl-3-trimethylammoniumpropane (DMTAP) or the anionic amphiphile 1,2-dimyristoyl-sn-glycero-3-phosphoglycerol (DMPG). Three sets of quadrupolar splittings, one from each of the three deuteron labelling positions, and three sets of dipolar splittings ((13)C(alpha)-(31)P, (13)C(alpha)-(13)C(beta), (13)C(beta)-(14)N), were measured at each surface charge, along with the (31)P residual chemical shift anisotropy. The torsion angle analysis assumed fast anisotropic rotation of POPC about its long molecular axis, thus projecting all NMR interactions onto that director axis of motion. Dipolar, quadrupolar and chemical shift anisotropies were calculated as a function of the phosphocholine internal torsion angles by first transforming into a common reference frame affixed to the phosphocholine group prior to motional averaging about the director axis. A comparison of experiment and calculation provided the two order parameters specifying the director orientation relative to the molecule, plus the torsion angles alpha(3), alpha(4) and alpha(5). Surface charge was found to have little effect on the torsion angle alpha(5) (rotations about C(alpha)-C(beta)), but to have large and inverse effects on torsion angles alpha(3) [rotations about P-O(11)] and alpha(4) [rotations about O(11)-C(alpha)], yielding a net upwards tilt of the P-N vector in the presence of cationic surface charge, and a downwards tilt in the presence of anionic surface charge, relative to neutrality. PMID:14745788

Semchyschyn, Darlene J; Macdonald, Peter M

2004-02-01

119

Quadrupolar particles in a nematic liquid crystal: Effects of particle size and shape  

NASA Astrophysics Data System (ADS)

We investigate the effects of particle size and shape on the quadrupolar (Saturn-ring-like) defect structures formed by a nematic liquid crystal around nm-sized and ?m -sized particles with spherical and spherocylindrical shapes. We also report results for the potentials of mean force in our systems, calculated using a mesoscale theory for the tensor order parameter Q of the nematic. Our results indicate that for pairs of nm-sized particles in close proximity, the nematic forms “entangled hyperbolic” defect structures regardless of the shape of the nanoparticles. In our calculations with nanoparticles we did not observe any other entangled or unentangled defect structures, in contrast to what was reported for pairs of ?m -sized spherical particles. Such a finding suggests that the “entangled hyperbolic” defect structures are the most stable for pairs of nanoparticles in close proximity. For pairs of ?m -sized particles, our results indicate that the nematic forms entangled “figure-of-eight” defect structures around pairs of spheres and spherocylinders. Our results suggest that the transition between “entangled hyperbolic” and figure-of-eight defect structures takes place when the diameter of the particle is between D=100nm and 1?m . We have also calculated the torques that develop when pairs of spherocylindrical nanoparticles in a nematic approach each other. Our calculations suggest that the nematic-mediated interactions between the nm-sized particles are fairly strong, up to 5700 kBT for the case of pairs of spherocylindrical nanoparticles arranged with their long axis parallel to each other. Furthermore, these interactions can make the particles to bind together at specific locations, and thus could be used to assemble the particles into ordered structures with different morphologies.

Hung, Francisco R.

2009-02-01

120

Nuclear magnetic relaxation in [sup 13]CH[sub 2] and [sup 13]CH[sub 3] coupled spin systems and variable angle spinning lineshape analysis for quadrupolar nuclei with half integer spins  

SciTech Connect

The carbon-13 multiplet spin-lattice relaxation in [sup 13]CH[sub 2] and [sup 13]CH[sub 3] spin systems is studied in detail by various nonselective and selective pulse techniques. Simultaneous fitting of the resulting relaxation curves with various rates and initial conditions allows for the extraction of both auto- and cross-correlated dipolar spectral densities which can provide detailed information on the molecular anisotropic reorientation. In addition, the [sup 13]CH[sub 3] coupled spin relaxation can characterize the methyl internal rotation dynamics. The cross-correlation between the dipolar and chemical shift anisotropy (CSA) interactions is found to be appreciable. Dipolar-CSA cross-correlated spectral densities introduce relaxation pathways that couple together magnetization modes with different spin inversion symmetries. Consideration of the dipolar-CSA cross-correlated spectral densities not only improves the accuracy of the measurement of dipolar spectral densities but also allows for the determination of the dipolar-CSA cross-correlated spectral densities themselves, providing a new measure of the anisotropy of the shielding tensor. NMR spectroscopy of quadrupolar nuclei in solids generally yields broad lines even when magic angle spinning is applied. Broadening of the central transition of quadrupolar nuclei with half integer spins is caused by the anisotropy of the second order quadrupolar interaction. A straightforward approach is presented that combines average Hamiltonian theory and a numerical solution of a classical banded matrix describing the equation of motion for a quadrupolar nucleus under variable angle sample spinning conditions. At either of two fourth rank magic angles, a simple three parameter lineshape is obtained, and the three breakpoints are related directly to the quadrupolar constant and its asymmetry parameter.

Zheng, Z.

1992-01-01

121

(14)N solid-state NMR: a sensitive probe of the local order in zeolites.  

PubMed

Local order in as-synthesised zeolites templated by tetraalkylammonium cations is proven from solid-state (14)N NMR and related quadrupolar parameters, opening new perspectives in the study of porous materials. PMID:23877332

Dib, Eddy; Mineva, Tzonka; Gaveau, Philippe; Alonso, Bruno

2013-10-01

122

Quantum state tomography and quantum logical operations in a three qubits NMR quadrupolar system  

Microsoft Academic Search

In this work, we present an implementation of quantum logic gates and algorithms in a three effective qubits system, represented by a (I = 7\\/2) NMR quadrupolar nuclei. To implement these protocols we have used the strong modulating pulses (SMP). The various stages of each implementation were verified by quantum state tomography (QST). It is presented here the results for

A. G. Araujo-Ferreira; Carlos Alexandre Brasil; D. O. Soares-Pinto; E. R. deAzevedo; T. J. Bonagamba; J. Teles

2011-01-01

123

Chemical bonding differences evidenced from J-coupling in solid state NMR experiments involving quadrupolar nuclei  

Microsoft Academic Search

Small scalar J-coupling between quadrupolar nuclei and spin 1\\/2 can be measured in inorganic solids using J-Resolved experiments and further used to acquire 2D J-HQMC heteronuclear correlation, giving detailed insight into the chemical bonding scheme.

Dominique Massiot; Franck Fayon; Bruno Alonso; Julien Trebosc; Jean-Paul Amoureux

2003-01-01

124

A General Strategy for the NMR Observation of Half -Integer Quadrupolar Nuclei in Dilute Environments  

SciTech Connect

A general strategy for the observation of low y half-integer quadrupolar nuclides in biological systems is presented. The basic idea is to combine low temperature (5-100 K) with cross-polarization experiments while employing a so-called Carr-Purcell Meiboom-Gill spin-echo sequence (QCPMG).

Lipton, Andrew S. (BATTELLE (PACIFIC NW LAB)); Sears, Jesse A. (BATTELLE (PACIFIC NW LAB)); Ellis, Paul D. (BATTELLE (PACIFIC NW LAB))

2001-07-17

125

Remarkable effect of iridium cyclometalation on the nonlinear absorption properties of a quadrupolar imine ligand.  

PubMed

A new type of dinuclear iridium complex, based on a quadrupolar Schiff base ligand, is synthesized and its structure fully characterized. Its linear and nonlinear spectroscopic properties are investigated, evidencing a strong contribution of the metal-to-ligand transitions not only to the linear absorption but also to the two- and three-photon absorption properties. PMID:24020389

Massue, Julien; Olesiak-Banska, Joanna; Jeanneau, Erwann; Aronica, Christophe; Matczyszyn, Katarzyna; Samoc, Marek; Monnereau, Cyrille; Andraud, Chantal

2013-09-10

126

Square colloidal lattices and pair interaction in a binary system of quadrupolar nematic colloids.  

PubMed

Spherical colloidal particles with normal and tangential surface director alignment in a nematic liquid crystal induce elastic quadrupoles of opposite signs that attract one another along and perpendicular to the director. We utilize this unique angular profile of the mixed quadrupolar interaction to build 2D crystals with square lattices by laser tweezers. PMID:21599188

Ognysta, U M; Nych, A B; Uzunova, V A; Pergamenschik, V M; Nazarenko, V G; Škarabot, M; Muševi?, I

2011-04-25

127

Matrix-shimmed ion cyclotron resonance ion trap simultaneously optimized for excitation, detection, quadrupolar axialization, and trapping  

Microsoft Academic Search

A different symmetry is required to optimize each of the three most common Fourier transform ion cyclotron resonance mass\\u000a spectrometry (FT-ICR MS) electric potentials in a Penning (ICR) ion trap: one-dimensional dipolar ac for excitation (or detection),\\u000a two-dimensional azimuthal quadrupolar ac excitation for ion axialization, and three-dimensional axial quadrupolar dc potential\\u000a for ion axial confinement (trapping). Since no single trap

George S. Jackson; Forest M. White; Shenheng Guan; Alan G. Marshall

1999-01-01

128

Dipolar and Scalar Couplings in Solid State NMR of Quadrupolar Nuclei  

Microsoft Academic Search

Summary.  ?Most NMR-active nuclei found in the periodic table have a quadrupole moment. In combination with a nonsymmetric electron\\u000a distribution a strong NMR-active interaction results, which very often overshadows the dipolar and scalar couplings. This\\u000a article aims at reviewing how these interactions manifest themselves in quadrupolar NMR and how they can be exploited for\\u000a resonance assignment and structure elucidation, in spite

Alexej Jerschow

2002-01-01

129

Vacuum interrupters with axial magnetic field contacts based on bipolar and quadrupolar design  

Microsoft Academic Search

Axial magnetic field (AMF) contacts are applied within vacuum interrupters especially for high short-circuit currents. In this paper, two AMF contact designs based on a bipolar and a quadrupolar magnetic field arrangement and their characteristics are presented. In the first section, both principles are discussed. This is followed by three-dimensional field simulations performed by means of a finite-element-analysis program. The

Harald Fink; Markus Heimbach; Wenkai Shang

2001-01-01

130

High-Resolution NMR of Quadrupolar Nuclei in the Solid State  

SciTech Connect

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.

Gann, Sheryl Lee

1995-11-30

131

Dominant biaxial quadrupolar contribution to the nematic potential of mean torque  

Microsoft Academic Search

Within the general quadrupolar model for biaxial nematic liquid crystals, whose potential of mean torque extends that in the Maier-Saupe theory with two extra interaction terms, we propose a quantitative criterion to identify the dominant biaxial interaction. We show that the ratio of the biaxial-to-uniaxial and uniaxial-to-isotropic transition temperatures is almost independent of one interaction parameter, thus indicating the other

Fulvio Bisi; Geoffrey R. Luckhurst; Epifanio G. Virga

2008-01-01

132

Spectral editing in solid-state MAS NMR of quadrupolar nuclei using selective satellite inversion  

Microsoft Academic Search

A sensitivity enhancement method based on selective adiabatic inversion of a satellite transition has been employed in a (?\\/2)CT–(?)ST1–(?\\/2)CT spectral editing sequence to both enhance and resolve multisite NMR spectra of quadrupolar nuclei. In addition to a total enhancement of 2.5 times for spin 3\\/2 nuclei, enhancements up to 2.0 times is reported for the edited sites in a mixture

Krishna K. Dey; S. Prasad; Jason T. Ash; Michael Deschamps; Philip J. Grandinetti

2007-01-01

133

Weak surface energy in nematic dispersions: Saturn ring defects and quadrupolar interactions  

Microsoft Academic Search

:   The role of surface energy in the behavior of colloidal particles in liquid crystalline phases is investigated. When the surface\\u000a energy dominates, a hedgehog defect is formed and, according to an electrostatic analogy, the distortions around the particles\\u000a exhibit a dipolar character. By contrast, for weaker anchoring, the configuration becomes quadrupolar as evidenced by the\\u000a structure of latex clusters

O. Mondain-Monval; J. C. Dedieu; T. Gulik-Krzywicki; P. Poulin

1999-01-01

134

Resonant Raman scattering by quadrupolar vibrations of NiAg core-shell nanoparticles  

Microsoft Academic Search

Low-frequency Raman-scattering experiments have been performed on thin films consisting of nickel-silver composite nanoparticles embedded in alumina matrix. It is observed that the Raman scattering by the quadrupolar modes, strongly enhanced when the light excitation is resonant with the surface dipolar excitation, is mainly governed by the silver electron contribution to the plasmon excitation. The Raman results are in agreement

Hervé Portales; Lucien Saviot; Eugène Duval; Mélanie Gaudry; Emmanuel Cottancin; Michel Pellarin; Jean Lermé; Michel Broyer

2002-01-01

135

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

SciTech Connect

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.

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

2009-11-09

136

Solution deuterium NMR quadrupolar relaxation study of heme mobility in myoglobin  

SciTech Connect

NMR spectroscopy has been used to monitor the quadrupolar relaxation and motional dynamics of {sup 2}H selectively incorporated into skeletal and side chain positions of the heme in sperm whale myoglobin. The hyperfine shifts of the heme resonances in paramagnetic states of myoglobin allow resolution of the signals of interest, and paramagnetic contributions to the observed line widths are shown to be insignificant. The {sup 2}H line widths for the skeletal positions of deuterohemin-reconstituted myoglobin yield a correlation time identical with that of overall protein tumbling (9 ns at 30{degree}C) and hence reflect an immobile heme group. The {sup 2}H NMR line widths of heme methyl groups exhibit motional narrowing indicative of very rapid internal rotation. Hence the methyl rotation is effectively decoupled from the overall protein tumbling, and the residual quadrupolar line width can be used directly to determine the protein tumbling rate. The {sup 2}H NMR lines from heme vinyl groups were found narrower than those from the heme skeleton. However, the range of quadrupolar coupling constants for sp{sup 2} hybridized C-{sup 2}H bonds does not permit an unequivocal interpretation in terms of mobility. 48 refs., 4 figs.

Johnson, R.D.; La Mar, G.N.; Smith, K.M.; Parish, D.W.; Langry, K.C. (Univ. of California, Davis (USA))

1989-01-18

137

Molecular dynamics of half-integer quadrupolar nuclei studied by QCPMG solid-state NMR experiments on static and rotating samples. Theory and simulations  

NASA Astrophysics Data System (ADS)

Simulations of QCPMG NMR type experiments have been used to explore dynamic processes of half-integer quadrupolar nuclei in solids. By setting up a theoretical approach that is well suited for efficient numerical simulations the QCPMG type experiments have been analyzed regarding the effect of the magnitude of the EFG- and CSA-tensors, the spin-quantum number, different dynamical processes and MAS. Compared to the QE experiment the QCPMG experiment offers not only intensity gain by an order of magnitude and changes in overall lineshape as a function of the kinetic rate constant but the lineshape of the individual spin-echo sidebands is also very sensitive towards dynamics. Hereby a visual identification of the dynamics is obtained. In common for all the simulations the spin-echo sidebands are narrow in the slow (k ? 102 Hz) and the fast (k ? 107 Hz) dynamic regime whereas they are broadened in the intermediate regime 103 ? k ? 107 Hz. The maximum intensity of the spin-echo sidebands for two-site jumps is highly dependent on the type of anisotropic interactions involved and the type of QCPMG experiment. Hence, in the fast limit the maximum intensity was 140% of the initial intensity when significant CSA was present or under the QCPMG-MAS experiment compared to 89 or 71% for the static experiment influenced by the quadrupolar interaction only. For 3-, 4-, and 6-site jumps the maximum intensity in the fast limit reached up to 339% of the intensity in the static limit.

Larsen, Flemming H.

2004-12-01

138

Re-entrant magnetic-field-induced charge and spin gaps in the coupled dual-chain quasi-one-dimensional organic conductor perylene2[Pt(mnt)2  

NASA Astrophysics Data System (ADS)

An inductive method is used to follow the magnetic-field-dependent susceptibility of the coupled charge density wave (CDW) and spin-Peierls (SP) ordered state behavior in the dual-chain organic conductor perylene2[Pt(mnt)2]. In addition to the coexisting SP-CDW state phase below 8 K and 20 T, the measurements show that a second spin-gapped phase appears above 20 T that coincides with a field-induced insulating phase. The results support a strong coupling of the CDW and SP order parameters even in high magnetic fields, and provide new insight into the nature of the magnetic susceptibility of dual-chain spin and charge systems.

Winter, L. E.; Brooks, J. S.; Schlottmann, P.; Almeida, M.; Benjamin, S.; Bourbonnais, C.

2013-08-01

139

Directed Transformation from Quadrupolar to Dipolar Nematic Colloids by an In-Plane Electric Field  

NASA Astrophysics Data System (ADS)

We demonstrate direction-controlled transformation from quadrupolar to dipolar nematic colloids using an in-plane electric field. When the electric field is applied in the direction perpendicular to the rubbing direction, a splay-bend wall is induced, which traps colloidal particles. Above the applied electric field of 0.14 V/?m, a Saturn-ring defect shrinks into a hedgehog defect due to the symmetric reorientation of the liquid crystal molecules around the particle. The direction of the shrinking is determined by the pretilt angle of the liquid crystal and the field direction near the edge of the electrode.

Tagashira, Kenji; Asakura, Keita; Yoshida, Hiroyuki; Ozaki, Masanori

2013-02-01

140

Three-pulse spin echo signals from quadrupolar nuclei in magnetic materials.  

PubMed

The time evolutions of the three-pulse spin echo signals from quadrupolar nuclei (63)Cu and (53)Cr in ferromagnetic CuCr(2)S(4):Sb have been investigated at the temperature T=77K. The experimental results were well explained by the developed theory of the time evolutions of the three-pulse echoes. The main assumption of this theory is the assumption that the temporal fluctuations in the electron magnetization lead to the fluctuations in the hyperfine and quadrupole interaction Hamiltonians. PMID:20153609

Polulyakh, S N; Sergeev, N A; Gorbovanov, A I; Berzhansky, V N

2010-01-22

141

Quadrupolar gravitational radiation as a test-bed for f( R)-gravity  

NASA Astrophysics Data System (ADS)

The debate concerning the viability of f( R)-gravity as a natural extension of General Relativity could be realistically addressed by using results coming from binary pulsars like PSR 1913 + 16. To this end, we develop a quadrupolar approach to the gravitational radiation for a class of analytic f( R)-models. We show that experimental results are compatible with a consistent range of f( R)-models. This means that f( R)-gravity is not ruled out by the observations and gravitational radiation (in strong field regime) could be a test-bed for such theories.

Laurentis, Mariafelicia De; Capozziello, Salvatore

2011-12-01

142

Temperature- and Magnetic-Field-Induced Change of Electric Polarization in a Multiferroic Mn0.93Co0.07W0.93O4-? Single Crystal  

NASA Astrophysics Data System (ADS)

We have investigated magnetic and electrical properties in a multiferroic Mn0.93Co0.07W0.93O4-? single crystal grown using the flux method, in which spiral spin orderings are known to be stabilized and thus magnetically induced electric polarization develops consistent with the spin current model. Upon temperature being lowered, two successive magnetic transitions appeared at TN1 = 13.0 and TN2 = 12.2 K. While there was no development of ferroelectric polarization P below TN1, a dominant P along the a-axis (Pa) and a small P along the b-axis (Pb) clearly developed below TN2, suggesting the stabilization of a spiral order with its basal plane close to the ac-plane. The magnetization measurements also support the existence of the spiral order with ac-basal plane below TN2 by exhibiting the largest spin susceptibility along the b-axis and the smaller ones along the a- and c-axes. Upon further lowering temperature below T* = 10.1 K, Pa starts to decrease significantly accompanied by a small increase of Pb while the magnetic susceptibility along the c-axis gradually becomes the largest and concomitantly shows a saturation. We have also found that the magnitude of Pa or Pb can be controlled smoothly at low temperatures as a function of magnetic field less than 9 T. These findings show that the magnitude and direction of the electric polarization vector in Mn0.93Co0.07W0.93O4-? can be varied as a function of temperature and magnetic field via the changes in the properties of the associated spiral phases.

Yan, Li Qin; Lee, Bumsung; Chun, Sae Hwan; Kim, Ingyu; Chung, Jae-Ho; Kim, Sung Baek; Park, Ju-Young; Lee, Suk Ho; Chai, Yisheng; Kim, Kee Hoon

2013-09-01

143

Spin-glass state and magnetic-field-induced phenomena in distorted Eu{sub 0.58}Sr{sub 0.42}MnO{sub 3} perovskite  

SciTech Connect

Magnetic and magnetoresistance measurements were carried out on a distorted perovskite, Eu{sub 0.58}Sr{sub 0.42}MnO{sub 3}. In the absence of applied magnetic field, this compound is an insulator down to 5 K. Results of the ac- and dc-susceptibility measurements suggest a spin-glass ground state. An applied field of 7 T drives the insulator ground state to a ferromagnetic metallic state below T{sub C}=120 K. For a range of intermediate fields, the compound undergoes insulator-metal-insulator transitions which resemble those of 1:1 Mn{sup 3+}/Mn{sup 4+} charge-ordered compounds. A temperature-field phase diagram is established which depicts different magnetic and electronic states. {copyright} {ital 1997} {ital The American Physical Society}

Sundaresan, A.; Maignan, A.; Raveau, B. [Laboratoire CRISMAT, ISMRA, 6 Boulevard du Marechal Juin, 14050 Caen Cedex (France)

1997-03-01

144

Strong two-photon fluorescence enhanced jointly by dipolar and quadrupolar modes of a single plasmonic nanostructure  

NASA Astrophysics Data System (ADS)

A single gold nano-cylinder presenting multipolar plasmon resonances to enhance two-photon fluorescence is investigated employing three dimensional finite-difference time-domain method. Cylinders of large dimension usually display dipolar and quadrupolar plasmonic resonances. We demonstrate that the dipolar resonance can couple with the incident light resulting in a large localized field enhancement which increases the molecular excitation rate. At the same time, the radiative quadrupolar mode overlaps with the emission band of excited fluorophores to assist the fluorescence emission due to an enhancement in the quantum efficiency. Such dipole-quadrupole jointly enhanced two-photon fluorescence exhibits exceptionally promise in brighter label design.

Zhang, Tianyue; Lu, Guowei; Liu, Jie; Shen, Hongming; Perriat, Pascal; Martini, Matteo; Tillement, Olivier; Gong, Qihuang

2012-07-01

145

Quadrupolar nuclear magnetic resonance spectroscopy in solids using frequency-swept echoing pulses.  

PubMed

The acquisition of ideal powder line shapes remains a recurring challenge in solid-state wideline nuclear magnetic resonance (NMR). Certain species, particularly quadrupolar spins in sites associated with large electric field gradients, are difficult to excite uniformly and with good efficiencies. This paper discusses some of the opportunities that arise upon departing from standard spin-echo excitation approaches and switching to echo sequences that use low-power, frequency-swept radio frequency (rf) pulses instead. The reduced powers demanded by such swept rf fields allow one to excite spins in different crystallites efficiently and with orientation-independent pulse angles, while the large bandwidths of interest that are needed by the measurement can be covered, thanks to the use of broadband frequency sweeps. The fact that the spins' evolution and ensuing dephasing starts at the beginning of such rf manipulation calls for the use of spin-echo sequences; a number of alternatives capable of providing the desired line shapes both in the frequency and in the time domains are introduced and experimentally demonstrated. Sensitivity- and lineshape-wise these experiments are competitive vis-a-vis current implementations of wideline quadrupolar NMR based on hard rf pulses; additional opportunities that may derive from these ideas are also briefly discussed. PMID:18035888

Bhattacharyya, Rangeet; Frydman, Lucio

2007-11-21

146

A NON-RADIAL ERUPTION IN A QUADRUPOLAR MAGNETIC CONFIGURATION WITH A CORONAL NULL  

SciTech Connect

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 {approx}2 Multiplication-Sign 10{sup 31} 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 Degree-Sign 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.

Sun Xudong; Hoeksema, J. Todd; Liu Yang; Hayashi, Keiji [W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305 (United States); Chen Qingrong, E-mail: xudong@sun.stanford.edu [Department of Physics, Stanford University, Stanford, CA 94305 (United States)

2012-10-01

147

Repetitive sideband-selective double frequency sweeps for sensitivity enhancement of MAS NMR of half-integer quadrupolar nuclei  

NASA Astrophysics Data System (ADS)

A sensitivity enhancement scheme aiming at selective adiabatic inversion of a single set of satellite transition sidebands under magic angle spinning has been employed on samples of albite containing a single moderately distorted 27Al site and zoisite containing two highly distorted octahedral 27Al sites. Overall enhancements of ˜2.5 for albite and ˜3 for the two AlO6 sites of zoisite are reported by applying this scheme at different spinning speeds reflecting the versatility of this enhancement scheme which achieves significant signal-to-noise enhancements for the systems with moderately high quadrupolar coupling and high quadrupolar coupling. Repeating the sensitivity enhancement scheme and signal readout several times without allowing for spin-lattice relaxation leads to sensitivity enhancements of factors of ˜4 for albite and ˜5 for zoisite which substantially increases the detectability of the quadrupolar sites. The effectiveness of this scheme at high magnetic field under very fast magic angle spinning has been demonstrated. Finally, the possibility of performing spectral editing by selective enhancement of one of the quadrupolar sites in zoisite whilst keeping the other site unaffected has been explored.

Goswami, M.; van Bentum, P. J. M.; Kentgens, A. P. M.

2012-06-01

148

Effect of pressure on structure of oxide glasses at high pressure: Insights from solid-state NMR of quadrupolar nuclides  

Microsoft Academic Search

Revealing the structure of oxide glasses at high pressure remains a fundamental yet difficult problem in modern physical and chemical sciences. The recent advances in solid-state NMR techniques used for quadrupolar nuclides offer a considerably improved resolution of atomic sites, unveiling previously unknown structural details of oxides glasses at high pressure. Here, we present an overview of the recent progress

Sung Keun Lee

2010-01-01

149

Strong Magnetic Field Induced Changes of Gene Expression in Arabidopsis  

NASA Astrophysics Data System (ADS)

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.

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

2005-07-01

150

Magnetic field induced enhancement in thermal conductivity of magnetite nanofluid  

NASA Astrophysics Data System (ADS)

Magnetite nanofluid is synthesized using continuous chemical process. Powder x-ray diffraction and transmission electron microscopy show single phase spinel structure with size of 9.83 and 9.9 nm, respectively. Thermal conductivity of magnetite nanofluid has been studied as a function of transverse magnetic field and temperature. We found almost 30% enhancements in thermal conductivity for 4.7% volume fraction under transverse magnetic field. This result is explained on the basis of formation of continuous three-dimensional zipperlike structure of magnetic nanoparticles inside magnetic fluid. The temperature dependent thermal conductivity shows no enhancement in the temperature region of 25-65 °C.

Parekh, Kinnari; Lee, Hyo Sook

2010-05-01

151

Magnetic field induced by elliptical instability in a rotating spheroid  

NASA Astrophysics Data System (ADS)

The tidal or the elliptical instability of the rotating fluid flows is generated by the resonant interaction of the inertial waves. In a slightly elliptically deformed rotating sphere, the most unstable linear mode is called the spin-over mode, and is a solid body rotation versus an axis aligned with the maximum strain direction. In the non-viscous case, this instability corresponds to the median moment of the inertial instability of the solid rotating bodies. This analogy is furthermore illustrated by an elliptical top experiment, which shows the expected inviscid heteroclinic behaviour. In geophysics, the elliptical instability may appear in the molten liquid cores of the rotating planets, which are slightly deformed by the tidal gravitational effects of the close bodies. It may then participate in the general outer core dynamics and possibly the geodynamo process. In this context, Kerswell and Malkus (Kerswell, R.R. and Malkus, W.V.R., Tidal instability as the source for Io's magnetic signature. Geophys. Res. Lett., 1998, 25, 603 606) showed that the puzzling magnetic field of the Jovian satellite Io may indeed be induced by the elliptically unstable motions of its liquid core that deflect the Jupiter's magnetic field. Our magnetohydrodynamics (MHD) experiment is a toy-experiment of this geophysical situation and demonstrates for the first time the possibility of an induction of a magnetic field by the flow motions due to the elliptical instability. A full analytical calculation of the magnetic dipole induced by the spin-over is presented. Finally, exponential growths of this induced magnetic field in a slightly deformed rotating sphere filled with galinstan liquid metal are measured for different rotating rates. Their growth rates compare well with the theoretical predictions in the limit of a vanishing Lorentz force.

Lacaze, L.; Herreman, W.; Le Bars, M.; Le Dizès, S.; Le Gal, P.

2006-10-01

152

Magnetic field induced lattice ground states from holography  

NASA Astrophysics Data System (ADS)

We study the holographic field theory dual of a probe SU(2) Yang-Mills field in a background (4 + 1)-dimensional asymptotically Anti-de Sitter space. We find a new ground state when a magnetic component of the gauge field is larger than a critical value. The ground state forms a triangular Abrikosov lattice in the spatial directions perpendicular to the magnetic field. The lattice is composed of superconducting vortices induced by the condensation of a charged vector operator. We perform this calculation both at finite temperature and at zero temperature with a hard wall cutoff dual to a confining gauge theory. The study of this state may be of relevance to both holographic condensed matter models as well as to heavy ion physics. The results shown here provide support for the proposal that such a ground state may be found in the QCD vacuum when a large magnetic field is present.

Bu, Yan-Yan; Erdmenger, Johanna; Shock, Jonathan P.; Strydom, Migael

2013-03-01

153

Static magnetic field induced hypovitaminosis d in rat.  

PubMed

In the following study, we mainly investigate the effects of static magnetic field (SMF) (128 mT, 1 hr/day during 5 consecutive days) on 25-hydroxyvitamin D3 and calcium homeostasis. Wistar male rats, weighing 50-70 g, were randomly divided into four experimental groups: control, SMF-exposed rat, co-exposed rats (the last day and after exposure rats received a single dose of vitamin D per os) and supplemented with vitamin D group (without exposure to SMF). Exposure to SMF induced a decrease of plasmatic 25-hydroxyvitamin D3 level (P<0.001). While, calcium and phosphorus levels were not affected (P>0.05). The same treatment failed also to alter body, relative liver and kidney weights. Interestingly, oral supplementation with vitamin D corrected hypovitaminosis D induced by SMF. Likewise, the same treatment failed to alter calcium homeostasis. More studies are needed to evaluate how SMF induces hypovitaminosis D. PMID:23648376

Aïda, Lahbib; Frédéric, Lecomte; Soumaya, Ghodbane; Philippe, Hubert; Mohsen, Sakly; Hafedh, Abdelmelek

2013-05-01

154

Magnetic Fields Induced in the Solid Earth and Oceans  

Microsoft Academic Search

Electromagnetic induction in the Earth's interior is an important contributor to the near-Earth magnetic field. Oceans play a special role in the induction, due to their relatively high conductance of large lateral variability. Electric currents that generate secondary magnetic fields are induced in the oceans by two different sources: by time varying external magnetic fields, and by motion of the

A. Kuvshinov; N. Olsen

2005-01-01

155

Magnetic Field Induced Microwave Absorption in High-Temperature Superconductors  

NASA Astrophysics Data System (ADS)

The non-resonant microwave absorption technique is used to probe the electrodynamic behavior of the high temperature superconductors (HTSC) below the critical transition temperature. Flux quantization is studied in single crystal samples of rm Y_1Ba_2Cu_3O _{7-gamma} (YBCO) as a function of externally applied dc magnetic field at constant amplitude of the microwave magnetic field, and as a function of the microwave field amplitude at nominally zero dc field. Periodic oscillations in the modulated microwave absorption (MA) due to flux quantization are observed in both scans. In the microwave scan, only a single junction is activated in the temperature range 0.1 < t <= 0.9, where t = T/T_{ rm c} is the reduced temperature. Measurements of flux quantization are discussed in the context of a model describing the quantum transitions of a weakly connected superconducting ring. From the temperature dependence of the microwave scan spectra, the superconducting penetration depth lambda_{rm L} is shown to obey the empirical two-fluid model lambda_{L}(T)/lambda _{L}(0) = (1-t^4)^{ -1/2} in the temperature range critical current is found to have the temperature dependence given by rm J_{c}(T)/J_{c} (0) = rm (1-t)^{1.9+/- 0.2 } in the same temperature range and suggests a superconductor-normal-superconductor (SNS) junction. The microwave absorption has been studied directly as a function of temperature (DA) and applied magnetic field (FDA) at a given temperature for ceramic samples of YBCO and rm Bi_{1.65}Pb _{0.35}Sr_2Ca_2Cu_3O _{9.8} (BP2223). The temperature dependence of the FDA signals in the temperature regime near T_{rm c} (t > 0.8) is explained in terms of a thermally activated flux flow model. Values of 9.3 and 23 meV were obtained for the activation energy for the YBCO and BP2223 samples, respectively. The correspondence between the information obtained from the MA and the FDA signals is discussed. Results of a thermally modulated absorption (THMA) measurement are compared to the numerically computed temperature derivative of the DA curve. The FDA upon first exposure to field (virgin curve) is studied for ceramic samples of YBCO. A simple model based on resistively shunted Josephson junctions is shown to qualitatively account for almost all of the observations for the low-field dependent absorption signals. It is found that the junctions responsible for the field dependent absorption signals are superconductor -insulator-superconductor (SIS) junctions.

Kish, Kevin Francis Patrick

156

Temporally-Patterned Magnetic Fields Induce Complete Fragmentation in Planaria  

PubMed Central

A tandem sequence composed of weak temporally-patterned magnetic fields was discovered that produced 100% dissolution of planarian in their home environment. After five consecutive days of 6.5 hr exposure to a frequency-modulated magnetic field (0.1 to 2 µT), immediately followed by an additional 6.5 hr exposure on the fifth day, to another complex field (0.5 to 5 µT) with exponentially increasing spectral power 100% of planarian dissolved within 24 hr. Reversal of the sequence of the fields or presentation of only one pattern for the same duration did not produce this effect. Direct video evidence showed expansion (by visual estimation ?twice normal volume) of the planarian following the first field pattern followed by size reduction (estimated ?1/2 of normal volume) and death upon activation of the second pattern. The contortions displayed by the planarian during the last field exposure suggest effects on contractile proteins and alterations in the cell membrane’s permeability to water.

Murugan, Nirosha J.; Karbowski, Lukasz M.; Lafrenie, Robert M.; Persinger, Michael A.

2013-01-01

157

Magnetic-field induced screening effect and collective excitations  

SciTech Connect

We explicitly construct the fermion propagator in a magnetic field background B to take the lowest Landau-level approximation. We analyze the energy and momentum dependence in the polarization tensor and discuss the collective excitations. We find there appear two branches of collective modes in one of two transverse gauge particles; one represents a massive and attenuated gauge particle and the other behaves similar to the zero sound at finite density.

Fukushima, Kenji [Department of Physics, Keio University, Kanagawa 223-8522 (Japan)

2011-06-01

158

Quadrupolar relaxation of hyperpolarized krypton-83 as a probe for surfaces.  

PubMed

This work reports the first systematic study of relaxation experienced by the hyperpolarized (hp) noble gas isotope (83)Kr (I=9/2) in contact with surfaces. The spin-lattice relaxation of (83)Kr is found to depend strongly on the chemical composition of the surfaces in the vicinity of the gas. This effect is caused by quadrupolar interactions during brief periods of surface adsorption that are the dominating source of longitudinal spin relaxation in the (83)Kr atoms. Simple model systems of closest packed glass beads with uniform but variable bead sizes are used for the relaxation measurements. The observed relaxation rates depend strongly on the chemical treatment of the glass surfaces and on the surface to volume ratio. Hp (83)Kr NMR relaxation measurements of porous polymers with pore sizes of 70-250 microm demonstrate the potential use of this new technique for material sciences applications. PMID:16202568

Stupic, Karl F; Cleveland, Zackary I; Pavlovskaya, Galina E; Meersmann, Thomas

2005-10-03

159

Quadrupolar effects in PrCu{sub 2}Si{sub 2}  

SciTech Connect

As part of a systematic study of the crystal field (CF) potential in RCu{sub 2}Si{sub 2} compounds (R = Ce, Pr, Nd, Tb, Ho, Er) using inelastic neutron scattering, we have determined the CF level scheme and potential in the antiferromagnet PrCu{sub 2}Si{sub 2} both above and below T{sub N}. There have been recent speculations that the quadrupole moment of PrCu{sub 2}Si{sub 2} has been quenched by the quadrupolar Kondo effect. Using the CF potential derived from our results, we have calculated the quadrupole moment Q{sub 2} of PrCu{sub 2}Si{sub 2} and compared it to the other members of the RCu{sub 2}Si{sub 2} series. The temperature dependence of the quadrupole moment of PrCu{sub 2}Si{sub 2} is significantly weaker-than all the other compounds eg. it is approximately five times smaller than HoCu{sub 2}Si{sub 2}. Therefore, it is the CF potential which is responsible for quenching Q{sub 2} at low temperature rather than a quadrupolar Kondo effect. Furthermore, the CF Schottky contribution to C/T {nu} T{sup 2} is approximately linear above T{sub N} and explains the anomalously high linear term in the specific heat. However, the evolution of the CF potential across the rare earth series provides evidence of an enhanced hybridization contribution to the CF potential of PrCu{sub 2}Si{sub 2}, intermediate between the heavy fermion CeCu{sub 2}Si{sub 2} and the other rare earth compounds.

Osborn, R. [Argonne National Lab., IL (United States); Goremychkin, E.A. [Rutherford Appleton Lab., Chilton (United Kingdom). ISIS Science Div.

1994-05-01

160

Population and coherence transfer induced by double frequency sweeps in half-integer quadrupolar spin systems.  

PubMed

We have recently shown that the sensitivity of single- and multiple-quantum NMR experiments of half-integer (N/2) quadrupolar nuclei can be increased significantly by introducing so-called double frequency sweeps (DFS) in various pulse schemes. These sweeps consist of two sidebands generated by an amplitude modulation of the RF carrier. Using a time-dependent amplitude modulation the sidebands can be swept through a certain frequency range. Inspired by the work of Vega and Naor (J. Chem. Phys. 75, 75 (1981)), this is used to manipulate +/-(m - 1) <--> +/-m (3/2 < or = m < or = N/2) satellite transitions in half-integer spin systems simultaneously. For (23)Na (I = 3/2) and (27)Al (I = 5/2) spins in single crystals it proved possible to transfer the populations of the outer +/-m spin levels to the inner +/-1/2 spin levels. A detailed analysis shows that the efficiency of this process is a function of the adiabaticity with which the various spin transitions are passed during the sweep. In powders these sweep parameters have to be optimized to satisfy the appropriate conditions for a maximum of spins in the powder distribution. The effects of sweep rate, sweep range, and RF field strength are investigated both numerically and experimentally. Using a DFS as a preparation period leads to significantly enhanced central transition powder spectra under both static and MAS conditions, compared to single pulse excitation. DFSs prove to be very efficient tools not only for population transfer, but also for coherence transfer. This can be exploited for the multiple- to single-quantum transfer in MQMAS experiments. It is demonstrated, theoretically and experimentally, that DFSs are capable of transferring both quintuple-quantum and triple-quantum coherence into single-quantum coherence in I = 5/2 spin systems. This leads to a significant enhancement in signal-to-noise ratio and strongly reduces the RF power requirement compared to pulsed MQMAS experiments, thus extending their applicability. This is demonstrated by (27)Al 3QMAS experiments on 9Al(2)O(3). 2B(2)O(3) and the mineral andalusite. In the latter compound, Al experiences a quadrupolar-coupling constant of 15.3 MHz in one of the sites. Finally a 5QMAS spectrum on 9Al(2)O(3). 2B(2)O(3) demonstrates the sensitivity enhancement of this experiment using a double frequency sweep. PMID:11097810

Iuga, D; Schäfer, H; Verhagen, R; Kentgens, A P

2000-12-01

161

The "Príncipes de Asturias" nebula: a new quadrupolar planetary nebula from the IPHAS survey  

NASA Astrophysics Data System (ADS)

Context: .The Isaac Newton Telescope Photometric H? Survey (IPHAS) is currently mapping the Northern Galactic plane reaching to r'=20 mag with typically 1primeprime resolution. Hundreds of Planetary Nebulae (PNe), both point-like and resolved, are expected to be discovered. We report on the discovery of the first new PN from this survey: it is an unusual object located at a large galactocentric distance and has a very low oxygen abundance. Aims: .Detecting and studying new PNe will lead to improved estimates of the population size, binary fraction and lifetimes, and yield new insights into the chemistry of the interstellar medium at large galactocentric distances. Methods: .Compact nebulae are searched for in the IPHAS photometric catalogue, selecting those candidates with a strong H? excess in the r'-H? vs. r'-i' colour-colour diagram. Searches for extended nebulae are by visual inspection of the mosaics of continuum-subtracted H? images at a spatial sampling of 5×5 arcsec^2. Follow-up spectroscopy enables confirmation of the PNe, and their physico-chemical study. Results: .The first planetary nebula discovered via IPHAS imagery shows an intricate morphology: there is an inner ring surrounding the central star, bright inner lobes with an enhanced waist, and very faint lobular extensions reaching up to more than 100''. We classify it as a quadrupolar PN, a rather unusual class of planetary showing two pairs of misaligned lobes. From long-slit spectroscopy we derive T_e[ Nii] =12 800±1000 K, Ne = 390±40 cm-3, and chemical abundances typical of Peimbert's type I nebulae (He/H =0.13, N/O =1.8) with an oxygen abundance of 12+log(O/H)=8.17±0.15. A kinematic distance of 7.0+4.5-3.0 kpc is derived, implying an unusually large size of >4 pc for the nebula. The photometry of the central star indicates the presence of a relatively cool companion. This, and the evidence for a dense circumstellar disk and quadrupolar morphology, all of which are rare among PNe, support the hypothesis that this morphology is related to binary interaction.

Mampaso, A.; Corradi, R. L. M.; Viironen, K.; Leisy, P.; Greimel, R.; Drew, J. E.; Barlow, M. J.; Frew, D. J.; Irwin, J.; Morris, R. A. H.; Parker, Q. A.; Phillipps, S.; Rodríguez-Flores, E. R.; Zijlstra, A. A.

2006-10-01

162

Magnetic alignment and quadrupolar/paramagnetic cross-correlation in complexes of Na with LnDOTP5-  

NASA Astrophysics Data System (ADS)

The observation of a double-quantum filtered signal of quadrupolar nuclei (e.g. 23Na) in solution has been traditionally interpreted as a sign for anisotropic reorientational motion. Ling and Jerschow (2007) [23] have found that a 23Na double-quantum signal is observed also in solutions of TmDOTPNa5. Interference effects between the quadrupolar and the paramagnetic interactions have been reported to lead to the appearance of double-quantum coherences even in the absence of a residual quadrupolar interaction. In addition, such processes lead to differential linebroadening effects between the satellite transitions, akin to effects that are well known for dipolar-CSA cross-correlation. Here, we report experiments on sodium in the presence of LnDOTP compounds, where it is shown that these cross-correlation effects correlate well with the pseudo-contact shift. In addition, anisotropic g-values of the lanthanide compounds in question, can also lead to alignment within the magnetic field, and consequently to the appearance of line splitting and double-quantum coherences. The two competing effects are demonstrated and it is concluded that both cross-correlated relaxation and alignment in the magnetic field must be at work in the systems described here.

Eliav, Uzi; Chandra shekar, S.; Ling, Wen; Navon, Gil; Jerschow, Alexej

2012-03-01

163

Non-fermi liquid behavior in Pr-based dilute quadrupolar systems  

NASA Astrophysics Data System (ADS)

We have studied the low-temperature properties of PrLa1-xPb3 and PrLa1-xInAg2 with the crystal-electric-field ground state of a non-Kramers ?3 doublet to examine the correlation between the ?3 quadrupolar moments and the conduction electrons. In PrLa1-xPb3, a non-Fermi-liquid (NFL) behavior is observed for x?0.05 in the specific heat C/T and the electrical resistivity below 3 K. Moreover, application of magnetic field raises C/T rapidly, which demonstrates the presence of the residual entropy at lower temperatures. In PrLa1-xInAg2, NFL behavior is confirmed up to x=0.8 in the susceptibility and the specific heat below 15 K. It is supposed that the Kondo effect arising from the correlation between the dilute ?3 moments and the conduction electrons gives rise to NFL behavior in both systems.

Kawae, T.; Nakaie, Y.; Li, C. S.; Hitaka, M.; Tateiwa, N.; Kitai, T.

2006-05-01

164

Quantum spin nanotubes--frustration, competing orders and criticalities.  

PubMed

Recent developments of theoretical studies on spin nanotubes are reviewed, especially focusing on the S = 1/2 three-leg spin tube. In contrast to the three-leg spin ladder, the tube has a spin gap in the case of the regular-triangle unit cell when the rung interaction is sufficiently large. The effective theory based on the Hubbard Hamiltonian indicates a quantum phase transition to a gapless spin liquid due to the lattice distortion to an isosceles triangle. This is also supported by the numerical diagonalization and the density matrix renormalization group analyses. Furthermore, combining analytical and numerical approaches, we reveal several novel magnetic-field-induced phenomena: Néel, dimer, chiral and/or inhomogeneous orders, a new mechanism for the magnetization plateau formation, and others. The recently synthesized spin tube materials are also briefly introduced. PMID:21386560

Sakai, Tôru; Sato, Masahiro; Okamoto, Kiyomi; Okunishi, Kouichi; Itoi, Chigak

2010-09-14

165

Evidence for spiral magnetic order in the heavy fermion material CeRhIn{sub 5}  

SciTech Connect

We report {sup 115}In nuclear quadrupolar resonance measurements of the heavy fermion compound CeRhIn{sub 5} in the paramagnetic and antiferromagnetic states. The magnetic order is consistent with a model of helical modulation of the Ce moments that is incommensurate with the lattice, and the magnetic dynamics indicate possible two-dimensional behavior. (c) 2000 The American Physical Society.

Curro, N. J. [Condensed Matter and Thermal Physics, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Hammel, P. C. [Condensed Matter and Thermal Physics, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Pagliuso, P. G. [Condensed Matter and Thermal Physics, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Sarrao, J. L. [Condensed Matter and Thermal Physics, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Thompson, J. D. [Condensed Matter and Thermal Physics, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Fisk, Z. [National High Magnetic Field Laboratory and Florida State University, Tallahassee, Florida 32306 (United States)

2000-09-01

166

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

NASA Astrophysics Data System (ADS)

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.

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

2013-10-01

167

Two-Photon Absorption Properties of Proquinoidal D-A-D and A-D-A Quadrupolar Chromophores  

PubMed Central

We report the synthesis, one- and two-photon absorption spectroscopy, fluorescence, and electrochemical properties of a series of quadrupolar molecules that feature proquinoidal ?-aromatic acceptors. These quadrupolar molecules possess either donor-acceptor-donor (D–A–D) or acceptor-donor-acceptor (A–D–A) electronic motifs, and feature 4-N,N-dihexylaminophenyl, 4-dodecyloxyphenyl, 4-(N,N-dihexylamino)benzo[c][1,2,5]thiadiazolyl or 2,5-dioctyloxyphenyl electron donor moieties and benzo[c][1,2,5]thiadiazole (BTD) or 6,7-bis(3’,7’-dimethyloctyl)[1,2,5]thiadiazolo[3,4-g]quinoxaline (TDQ) electron acceptor units. These conjugated structures are highly emissive in nonpolar solvents and exhibit large spectral red-shifts of their respective lowest energy absorption bands relative to analogous reference compounds that incorporate phenylene components in place of BTD and TDQ moieties. BTD-based D-A-D and A-D-A chromophores exhibit increasing fluorescence emission red-shifts, and a concomitant decrease of the fluorescence quantum yield (?f) with increasing solvent polarity; these data indicate that electronic excitation augments benzothiadiazole electron density via an internal charge transfer mechanism. The BTD- and TDQ-containing structures exhibit blue-shifted two-photon absorption (TPA) spectra relative to their corresponding one-photon absorption (OPA) spectra, and display high TPA cross-sections (>100 GM) within these spectral windows. D-A-D and A-D-A structures that feature more extensive conjugation within this series of compounds exhibit larger TPA cross-sections consistent with computational simulation. Factors governing TPA properties of these quadrupolar chromophores are discussed within the context of a three-state model.

Susumu, Kimihiro; Fisher, Jonathan A. N.; Zheng, Jieru

2011-01-01

168

Solid-state NMR calculations for metal oxides and gallates: Shielding and quadrupolar parameters for perovskites and related phases  

NASA Astrophysics Data System (ADS)

The NMR parameters obtained from solid-state DFT calculations within the GIPAW approach for 17O- and 69/71Ga-sites in a range of predominantly oxide-based (group II monoxides, SrTiO3, BaZrO3, BaSnO3, BaTiO3, LaAlO3, LaGaO3, SrZrO3, MgSiO3 and Ba2In2O5), and gallate (?- and ?-Ga2O3, LiGaO2, NaGaO2, GaPO4 and LaGaO3) materials are compared with experimental values, with a view to the future application of a similar approach to doped phases of interest as candidate intermediate temperature solid oxide fuel cell (ITSOFC) electrolytes. Isotropic and anisotropic chemical shift parameters, quadrupolar coupling constants, and associated asymmetries are presented and analyzed. The unusual GaO5 site occurring in LaGaGe2O7 is also fully characterised. In general, it is found that the theoretical results closely track the experimental trends, though some deviations are identified and discussed, particularly in regard to quadrupolar ?Q-values. The high quality of the computed results suggests that this approach can be extended to study more complex and disordered phases.

Middlemiss, Derek S.; Blanc, Frédéric; Pickard, Chris J.; Grey, Clare P.

2010-05-01

169

Solid-state NMR calculations for metal oxides and gallates: shielding and quadrupolar parameters for perovskites and related phases.  

PubMed

The NMR parameters obtained from solid-state DFT calculations within the GIPAW approach for (17)O- and (69/71)Ga-sites in a range of predominantly oxide-based (group II monoxides, SrTiO(3), BaZrO(3), BaSnO(3), BaTiO(3), LaAlO(3), LaGaO(3), SrZrO(3), MgSiO(3) and Ba(2)In(2)O(5)), and gallate (alpha- and beta-Ga(2)O(3), LiGaO(2), NaGaO(2), GaPO(4) and LaGaO(3)) materials are compared with experimental values, with a view to the future application of a similar approach to doped phases of interest as candidate intermediate temperature solid oxide fuel cell (ITSOFC) electrolytes. Isotropic and anisotropic chemical shift parameters, quadrupolar coupling constants, and associated asymmetries are presented and analyzed. The unusual GaO(5) site occurring in LaGaGe(2)O(7) is also fully characterised. In general, it is found that the theoretical results closely track the experimental trends, though some deviations are identified and discussed, particularly in regard to quadrupolar eta(Q)-values. The high quality of the computed results suggests that this approach can be extended to study more complex and disordered phases. PMID:20335059

Middlemiss, Derek S; Blanc, Frédéric; Pickard, Chris J; Grey, Clare P

2010-01-13

170

NMR Imaging Using Second Order Quadrupole Broadened Resonances.  

PubMed

Theoretical and experimental results for NMR imaging measurements of powdered materials using the +(1/2) to -(1/2) transition of (1/2)-integerspin nuclei in the presence of a very large second-order electric quadrupolar broadening are presented. An "effective spin-(1/2)" formalism is developed to account for additional effects due to the presence of quadrupolar interactions comparable in size to the Zeeman interaction. A large (7.9 mT/cm-A, with a maximum current of approximately 20 A), rapid ( approximately 30 µs) pulsed linear gradient field is used with echoes and phase encoding techniques to obtain images in the limit gammaH1 is much narrower than the NMR linewidth. A one-dimensional projection of the second-order quadrupolar perturbed, 4-MHz-wide, +(1/2) left and right arrow -(1/2) transition for 63Cu in Cu2O powder is presented as an example. An experimental one-dimensional projection of a sample containing Cu2O and YBa2Cu3O6.7 is also presented. Copyright 1998 Academic Press. PMID:9632553

Swaminathan; Suits

1998-06-01

171

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

PubMed

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

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

2013-01-28

172

Competition between charge and superconducting orders in underdoped YBCO  

NASA Astrophysics Data System (ADS)

We report nuclear magnetic resonance measurements (NMR) showing that high magnetic fields induce a static, unidirectional, modulation of the charge density in the CuO2 planes of underdoped YBa2Cu3Oy [T. Wu et al., Nature 477, 191 (2011)]. The appearance of the charge order coincides with the Fermi surface reconstruction inferred from quantum oscillation and other transport measurements. This charge order appears to be most probably the same 4a-periodic stripe modulation as in La-214 cuprates. That it develops only when superconductivity fades away (no charge order is observed under strong fields parallel to the planes) and near the same 1/8 hole doping as in La-214 suggests that charge order, although visibly pinned by CuO chains in YBa2Cu3Oy, is an intrinsic propensity of the superconducting planes of high-Tc copper oxides. Since field induced stripe order is also compatible with neutron scattering data in La-214 and with STM data in Bi-2212, charge order could be a generic competitor of high Tc superconductivity. [4pt] Work performed with T. Wu, H. Mayaffre, S. Kr"amer, M. Horvatic, C. Berthier (LNCMI Grenoble), W.N. Hardy, R. Liang, D.A. Bonn (University of British Columbia, Vancouver)

Julien, Marc-Henri

2012-02-01

173

Orientational ordering of molecules of a multipolar fluid in an external electric field near an interface  

SciTech Connect

Thermodynamic perturbation theory has been used to describe the structure of a fluid consisting of linear dipolar-quadrupolar molecules in an external electric field near an interface. The general case in which the field is directed at an arbitrary angle to the interface has been considered. Expressions for the complete system of first- and second-order parameters describing the orientational ordering of the molecules in the nonuniform region have been derived.

Lebovka, N.I.; Mank, V.V.

1986-11-01

174

Order parameter dependence of the nematic liquid crystal anchoring energy: A numerical approach  

Microsoft Academic Search

We study the influence of the surface director disorientation and of the sub-surface director distortion on the surface order parameter and on the anchoring torque of a nematic liquid crystal (NLC). The problem is treated in the framework of the Landau-de Gennes theory with an anchoring energy of the form Tr [(Qij–Qoij)], where Qij is the NLC quadrupolar order parameter

Angelo Di Garbo; Maurizio Nobili

1995-01-01

175

TOPICAL REVIEW: Quantum spin nanotubes—frustration, competing orders and criticalities  

NASA Astrophysics Data System (ADS)

Recent developments of theoretical studies on spin nanotubes are reviewed, especially focusing on the S = 1/2 three-leg spin tube. In contrast to the three-leg spin ladder, the tube has a spin gap in the case of the regular-triangle unit cell when the rung interaction is sufficiently large. The effective theory based on the Hubbard Hamiltonian indicates a quantum phase transition to a gapless spin liquid due to the lattice distortion to an isosceles triangle. This is also supported by the numerical diagonalization and the density matrix renormalization group analyses. Furthermore, combining analytical and numerical approaches, we reveal several novel magnetic-field-induced phenomena: Néel, dimer, chiral and/or inhomogeneous orders, a new mechanism for the magnetization plateau formation, and others. The recently synthesized spin tube materials are also briefly introduced.

Sakai, Tôru; Sato, Masahiro; Okamoto, Kiyomi; Okunishi, Kouichi; Itoi, Chigak

2010-10-01

176

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

NASA Astrophysics Data System (ADS)

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.

Schulz, M.

2008-05-01

177

Enhancement of (14N) Quadrupolar Relaxation in the One Dimensional Conductor K2Pt(CN)4Br0.33.2H2O Due to Lattice Fluctuations above the Peierls Transition  

NASA Astrophysics Data System (ADS)

The spin-lattice relaxation T1 of 14N(I{=}1) nuclei in a single crystal of the mixed-valency platino-cyanate K2Pt(CN)4Br0.33.2H2O(KCP) quasi-one dimensional conductor has been measured in the temperature domain from room temperature down to the 3-D Peierls ordering below 120 K. A rapid increase of the quadrupolar relaxation is observed below 220 K which follows the power law 1/T1? r-1/2 where r{=}(T-Tp)/Tp. This behaviour is explained in terms of the critical slowing down of lattice fluctuations with a Landau-Ginzburg theory. The square root critical divergence of T1-1 is the signature of the harmonic regime for the order parameter fluctuations. The enhancement of T1-1 and the very wide 3-D critical width can be explained by the strong anisotropy of correlation lengths in this Q-1-D conductor.

Soda, G.; Bourbonnais, C.; Jerome, D.

1987-11-01

178

AN ENVELOPE DISRUPTED BY A QUADRUPOLAR OUTFLOW IN THE PRE-PLANETARY NEBULA IRAS 19475+3119  

SciTech Connect

IRAS 19475+3119 is a quadrupolar pre-planetary nebula (PPN), with two bipolar lobes, one in the east-west (E-W) direction and one in the southeast-northwest (SE-NW) direction. We have observed it in CO J = 2-1 with the Submillimeter Array at {approx}1'' resolution. The E-W bipolar lobe is known to trace a bipolar outflow and it is detected at high velocity. The SE-NW bipolar lobe appears at low velocity, and could trace a bipolar outflow moving in the plane of the sky. Two compact clumps are seen at low velocity around the common waist of the two bipolar lobes, spatially coincident with the two emission peaks in the NIR, tracing dense envelope material. They are found to trace the two limb-brightened edges of a slowly expanding torus-like circumstellar envelope produced in the late asymptotic giant branch phase. This torus-like envelope originally could be either a torus or a spherical shell, and it appears as it is now because of the two pairs of cavities along the two bipolar lobes. Thus, the envelope appears to be disrupted by the two bipolar outflows in the PPN phase.

Hsu, Ming-Chien; Lee, Chin-Fei, E-mail: mchsu@asiaa.sinica.edu.tw, E-mail: cflee@asiaa.sinica.edu.tw [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China)

2011-07-20

179

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

SciTech Connect

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.

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

180

An Envelope Disrupted by a Quadrupolar Outflow in the Pre-planetary Nebula IRAS 19475+3119  

NASA Astrophysics Data System (ADS)

IRAS 19475+3119 is a quadrupolar pre-planetary nebula (PPN), with two bipolar lobes, one in the east-west (E-W) direction and one in the southeast-northwest (SE-NW) direction. We have observed it in CO J = 2-1 with the Submillimeter Array at ~1'' resolution. The E-W bipolar lobe is known to trace a bipolar outflow and it is detected at high velocity. The SE-NW bipolar lobe appears at low velocity, and could trace a bipolar outflow moving in the plane of the sky. Two compact clumps are seen at low velocity around the common waist of the two bipolar lobes, spatially coincident with the two emission peaks in the NIR, tracing dense envelope material. They are found to trace the two limb-brightened edges of a slowly expanding torus-like circumstellar envelope produced in the late asymptotic giant branch phase. This torus-like envelope originally could be either a torus or a spherical shell, and it appears as it is now because of the two pairs of cavities along the two bipolar lobes. Thus, the envelope appears to be disrupted by the two bipolar outflows in the PPN phase.

Hsu, Ming-Chien; Lee, Chin-Fei

2011-07-01

181

Using the dipolar and quadrupolar moments to improve solar cycle predictions based on the polar magnetic fields  

NASA Astrophysics Data System (ADS)

The solar cycle and its associated magnetic activity are the main drivers behind changes in the interplanetary environment and the Earth's upper atmosphere. These changes have a direct impact on the lifetime of space-based assets and can create hazards to astronauts in space. In recent years there has been an effort to develop accurate solar cycle predictions (with aims at predicting the long-term evolution of space weather), leading to nearly a hundred widely spread predictions for the amplitude of solar cycle 24. In this presentation we show how cycle predictions can be made more accurate if performed separately for each hemisphere, taking advantage of information about both the dipolar and quadrupolar moments of the solar magnetic field. Additionally, by extending the relationship between polar flux at solar minimum and the amplitude of the next cycle to encompass a full century, we demonstrate the power of predictions based on the solar polar field -- paving the way for a new generation of better and more accurate solar cycle predictions.

Munoz-Jaramillo, Andres; Balmaceda, L. A.; DeLuca, E. E.

2013-07-01

182

Large two-photon absorption of terpyridine-based quadrupolar derivatives: towards their applications in optical limiting and biological imaging.  

PubMed

Developing organic chromophores with large two-photon absorption (TPA) in both organic solvents and aqueous media is crucial owing to their applications in solid-state photonic devices and biological imaging. Herein, a series of novel terpyridine-based quadrupolar derivatives have been synthesized. The influences of electron-donating group, type of conjugated bridge, as well as solvent polarity on the molecular TPA properties have been investigated in detail. In contrast to the case in organic solvents, bis(thienyl)-benzothiadiazole as a rigid conjugated bridge will completely quench molecular two-photon emission in aqueous media. However, the combination of alkylcarbazole as the donor and bis(styryl)benzene as a conjugation bridge can enlarge molecular TPA cross-sections in both organic solvent and aqueous media. The reasonable two-photon emission brightness for the organic nanoparticles of chromophores 3-5 in the aqueous media, prepared by the reprecipitation method, enables them to be used as probes for in vivo biological imaging. PMID:23281197

He, Tingchao; Lim, Zheng Bang; Ma, Lin; Li, Hairong; Rajwar, Deepa; Ying, Yongjun; Di, Ziyun; Grimsdale, Andrew C; Sun, Handong

2012-12-28

183

Something New Emerging: Tetrahedratic Order  

NASA Astrophysics Data System (ADS)

Nematic order conserves parity while tetrahedratic order does not. We found that parity conservation allows free energy gradient terms in uniaxial quadrupolar (Q_{ij}) and tetrahedral (T_{ijk}) order parameters to couple at lower order than spatially homogenous ones thereby accounting for the spontaneous appearance of traveling birefringent objects with a length scale in achiral (no preferred sense of rotation) banana liquid crystals. Here we present one of our first solutions, the twisty wrap, using a braid construction to highlights its topology. In the twisty wrap, one of the fields rotates with one hand, right hand say, while the other field rotates with the other hand, left hand, say, leading to an over all structure with no hand. This analysis implies that the observed isotropic liquid is tetrahedratic, T_d, an isotropic non-parity conserving liquid rather than O(3), the usual isotropic liquid. A non-parity conserving liquid in contact with a parity conservin g anisotropic entity could account for why the anisotropic entities always travel in the banana liquid crystal phase known as B7.

Cladis, P. E.

184

Giant magnetothermopower in charge ordered Nd0.75Na0.25MnO3  

NASA Astrophysics Data System (ADS)

We report magnetization, resistivity, and thermopower in the charge-orbital ordered antiferromagnet Nd0.75Na0.25MnO3. Magnetic-field induced collapse of antiferromagnetism is found to be accompanied by a giant negative magnetothermopower (=80%-100% for a field change of 5 T) over a wide temperature (T = 60-225 K) and giant magnetoresistance. While the field-induced metamagnetic transition in magnetization is reversible upon field-cycling at T > 40 K, it is irreversible at lower temperatures and this has impact on magnetoresistance, magnetothermopower as well as change in the temperature of the sample. Our results indicate high sensitivity of thermopower to changes in the magnetic state of the sample.

Maheswar Repaka, D. V.; Mahendiran, R.

2013-10-01

185

Deuteron NMR study of a long-chain smectic liquid crystal: molecular order and dynamics.  

PubMed

Deuteron Zeeman (T(1Z)) and quadrupolar (T(1Q)) spin-lattice relaxation times and quadrupolar splittings were measured in the nematic and smectic A phases of a chain-deuterated 4-n-octyloxy-4'-cyanobiphenyl (8OCB-d17) at 15.1 and 46 MHz. To model the NMR observables, the so-called pentane effect is used to limit the number of possible conformations in the chain, and is found to be a good approximation. The additive potential method is employed to construct the potential of mean torque using the quadrupolar splittings. A decoupled model is used to describe correlated internal motions in the chain, which are independent of the molecular reorientation. The latter motion is treated using the small-step rotational diffusion model of Nordio (Tarroni and Zannoni), while the former motion is described using a master rate equation. In the nematic phase, order director fluctuations are found to be necessary. The relaxation data in both mesophases were treated using a global target method, and the derived motional parameters are acceptable in comparison with those found for 6OCB. PMID:11970440

Dong, R Y

1999-11-01

186

19F-decoupling of half-integer spin quadrupolar nuclei in solid-state NMR: application of frequency-swept decoupling methods.  

PubMed

In solid-state NMR studies of minerals and ion conductors, quadrupolar nuclei like (7)Li, (23)Na or (133)Cs are frequently situated in close proximity to fluorine, so that application of (19)F decoupling is beneficial for spectral resolution. Here, we compare the decoupling efficiency of various multi-pulse decoupling sequences by acquiring (19)F-decoupled (23)Na-NMR spectra of cryolite (Na(3)AlF(6)). Whereas the MAS spectrum is only marginally affected by application of (19)F decoupling, the 3Q-filtered (23)Na signal is very sensitive to it, as the de-phasing caused by the dipolar interaction between sodium and fluorine is three-fold magnified. Experimentally, we find that at moderate MAS speeds, the decoupling efficiencies of the frequency-swept decoupling schemes SW(f)-TPPM and SW(f)-SPINAL are significantly better than the conventional TPPM and SPINAL sequences. The frequency-swept sequences are therefore the methods of choice for efficient decoupling of quadrupolar nuclei with half-integer spin from fluorine. PMID:21856132

Chandran, C Vinod; Hempel, Günter; Bräuniger, Thomas

2011-08-04

187

Magnetic-field-induced tunneling and minigap transport in double quantum wells  

SciTech Connect

We review recent theoretical and experimental results on low- temperature tunneling and in-plane transport properties in double quantum wells (DQWs) in an in-plane magnetic field B{parallel}. These properties arise from combined effect of B{parallel}-induced relative displacement of the wave vectors in the two QWs and the interwell tunneling. In weakly coupled DQWs, the tunneling conductance has two sharp maxima as a function of B{parallel}. In strongly coupled DQWs, a partial minigap is formed due to anticrossing of the two QW dispersion curves, yielding sharp B{parallel}-dependent structures in the density of states and in- plane transport properties. Excellent agreement is obtained between theory and data from GaAs/AlGaAs DQWs.

Lyo, S.K.; Simmons, J.A.; Harff, N.E.; Eiles, T.M.; Klem, J.F.

1995-08-01

188

Magnetic-field induced electric response of simple magnetoelectric composite rods  

NASA Astrophysics Data System (ADS)

A simple, long magnetoelectric (ME) composite rod with a long Pb(Zr,Ti)O3 (PZT) rod embedded in Terfenol-D/epoxy medium is reported. Our results indicate that there is a critical aspect ratio around 10 for the PZT rod, above which a larger aspect ratio plays a limited role in enhancing the ME effect. Obvious anisotropy and high sensitivity to the magnetic field were observed in the ME composite rod. The ability for further minimization of the rods, remarkable sensitivity and stability of such simple ME composite rods are advantageous for their practical applications in magnetic-field micro-sensors.

Ma, Jing; Shi, Zhan; Nan, C. W.

2008-08-01

189

Theory of magnetic-field-induced phase transitions in quasi-one-dimensional conductors  

NASA Astrophysics Data System (ADS)

A model for a layered quasi-one-dimensional metal in a strong magnetic field perpendicular to the layer is investigated. Renormalization group equations for this model are derived in the 'fast parquet' approximation. By solving these equations numerically, it is shown that, for any sign of electron interaction, a charge density wave (CDW) or spin density wave (SDW) forms in the system. For a sign of interaction corresponding to superconductivity, a series of phase transitions along the magnetic field between the different types of CDW or SDW occurs. The dependence of the CDW or SDW type on the magnetic field strength (H) is found by solving the renormalization group equations for different values of H. The present results can explain experimental data suggesting that the sequence of phase transitions in (TMTSF)2X compounds is induced by the magnetic field solely from the superconducting phase.

Iakovenko, V. M.

1987-08-01

190

Magnetic field induced dehybridization of the electromagnons in multiferroic TbMnO?.  

PubMed

We have studied the impact of the magnetic field on the electromagnon excitations in TbMnO? crystal. Applying a magnetic field along the c axis, we show that the electromagnons transform into pure antiferromagnetic modes, losing their polar character. Entering in the paraelectric phase, we are able to track the spectral weight transfer from the electromagnons to the magnon excitations and we discuss the magnetic excitations underlying the electromagnons. We also point out the phonons involved in the phase transition process. This reveals that the Mn-O distance plays a key role in understanding the ferroelectricity and the polar character of the electromagnons. Magnetic field measurements along the b axis allow us to detect a new electromagnon resonance in agreement with a Heisenberg model. PMID:21797635

Rovillain, P; Cazayous, M; Gallais, Y; Measson, M-A; Sacuto, A; Sakata, H; Mochizuki, M

2011-07-05

191

Magnetic-Field Induced Stability in Two-Flavor Color Superconductivity  

NASA Astrophysics Data System (ADS)

It has long been understood that the ground state of a superdense quark system, a Fermi liquid of weakly interacting quarks, is unstable with respect to the formation of diquark condensates. This nonperturbative phenomenon is essentially equivalent to the Cooper instability of conventional BCS superconductivity. As the quark pairs have nonzero color charge, this kind of superconductivity breaks the SU(3) color gauge symmetry, thus it is called color superconductivity. A peculiar feature of spin-zero color superconductivity is the lack of Meissner effect for a combination of the regular electromagnetic field and one of the gluon fields. This combination behaves as an in-medium electromagnetic field and as a consequence, a regular magnetic field can penetrate the color superconductor through its long-range in-medium component. Since the conditions of very high dense matter and very strong magnetic fields are naturally found in neutron stars, the investigations of magnetic field effects in color superconductivity are relevant for astrophysics. In this work we investigate the effects of an external magnetic field in the stability of the ground state of a neutral two-flavor color superconductor. Our results show that a strong magnetic field tends to increase the stability of the ground state, moving it from the unstable gapped region to the stable one.

Bhandari, Churna Bahadur

2011-12-01

192

Magnetic-Field Induced Isotropic to Nematic Phase Transition in Ferronematics  

Microsoft Academic Search

In this work the thermotropic liquid crystal 4-(trans-4 -n-hexylcyclohexyl)-isothiocyanato-benzene (6CHBT) was doped with differently shaped magnetic nanoparticles with the aim to increase the sensitivity of the liquid crystal on the external magnetic field. The volume concentration of the magnetic particles was . The phase transition temperature from isotropic to nematic phase in external magnetic fields up to 12 T was

Peter Kopcansky; Natália Tomasovicova; Martina Koneracka; Vlasta Zavisova; Milan Timko; Michal Hnatic; Nándor Eber; Tibor Toth-Katona; Jan Jadzyn; Juha Honkonen; Eric Beaugnon; Xavier Chaud

2011-01-01

193

Magnetic field induced rest potential shift of metallic electrodes in nitric acid solution  

Microsoft Academic Search

We have investigated the field-induced rest potential shift of Cr, Mn, Fe, Co, Ni, Cu, Zn, Sn, Bi, and stainless steel in nitric acid solution. Anodic rest potential shifts of up to 4 mV, 10 mV, 35 mV and 2.4 mV were observed for Mn, Zn, Fe and Ni, respectively, with an applied field of 1.5 T, whereas no shift

F. M. F. Rhen; P. Dunne; J. M. D. Coey

2006-01-01

194

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

NASA Astrophysics Data System (ADS)

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 oxide nanoparticles exhibit an extraordinary specific absorption rate (SAR [W/g]), which is much higher at clinically tolerable H0f combinations in comparison to hysteresis heating of larger multidomain particles. This was the renaissance of a cancer treatment method, which has gained more and more attention in the last few years. Due to the increasing number of randomized clinical trials preferentially in Europe with conventional E-field hyperthermia systems, the general medical and physical experience in hyperthermia application is also rapidly growing. Taking this increasing clinical experience carefully into account together with the huge amount of new biological data on heat response of cells and tissues, the approach of magnetic fluid hyperthermia (MFH) is nowadays more promising than ever before. The present contribution reviews the current state of the art and some of the future perspectives supported by advanced methods of the so-called nanotechnology.

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

1999-07-01

195

Electronic scattering of pseudo-magnetic field induced by local bump in graphene  

NASA Astrophysics Data System (ADS)

We investigated the electronic scattering properties of a local bump strain in graphene sheet in frame of Born approximation. The differential scattering cross section is a function of outgoing and incident angles and has the six-fold rotational symmetry with respect to both angles. The incident plane wave is scattered into two backward fan-waves in different directions in low energy limit and is split into two branches spanning the angle reversely proportional to the incident wavevector k in high energy limit. The total scattering cross section depends on incident wavevector by the form k5 in the former limit, while it is independent of k and sensitive to the incident orientation in the latter limit. We explained these features using the symmetry of the strain-induced pseudo-magnetic field.

Yang, Mou; Cui, Yan; Wang, Rui-Qiang; Zhao, Hong-Bo

2012-10-01

196

Measurements of the magnetic field induced by a turbulent flow of liquid metal  

SciTech Connect

Initial results from the Madison Dynamo Experiment provide details of the inductive response of a turbulent flow of liquid sodium to an applied magnetic field. The magnetic field structure is reconstructed from both internal and external measurements. A mean toroidal magnetic field is induced by the flow when an axial field is applied, thereby demonstrating the omega effect. Poloidal magnetic flux is expelled from the fluid by the poloidal flow. Small-scale magnetic field structures are generated by turbulence in the flow. The resulting magnetic power spectrum exhibits a power-law scaling consistent with the equipartition of the magnetic field with a turbulent velocity field. The magnetic power spectrum has an apparent knee at the resistive dissipation scale. Large-scale eddies in the flow cause significant changes to the instantaneous flow profile resulting in intermittent bursts of nonaxisymmetric magnetic fields, demonstrating that the transition to a dynamo is not smooth for a turbulent flow.

Nornberg, M.D.; Spence, E.J.; Kendrick, R.D.; Jacobson, C.M.; Forest, C.B. [Department of Physics, University of Wisconsin-Madison, 1150 University Avenue, Madison, Wisconsin 53706 (United States)

2006-05-15

197

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

NASA Astrophysics Data System (ADS)

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 Q R 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.

Wang, Xiang; Pu, Shengli; Ji, Hongzhu; Yu, Guojun

2012-05-01

198

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

PubMed

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

Wang, Xiang; Pu, Shengli; Ji, Hongzhu; Yu, Guojun

2012-05-15

199

An Experimental Determination of Static Magnetic Fields Induced Noise in Living Systems  

NASA Astrophysics Data System (ADS)

Living systems are constantly exposed to static magnetic fields (SMFs) from both natural and man-made sources. Exposures vary in dose and duration ranging from geomagnetic (˜50?T) to residential and industrial (˜10s of mT) fields. Efforts to characterize responses to SMFs have yielded conflicting results, showing a dependence on experimental variables used. Here we argue that low to moderate SMF exposure is a sub-threshold perturbation operating below thermal noise, and assays that evaluate statistical characteristics of a single cell may identify responses not consistently found by population averaging approaches. Recent studies of gene expression show that it is a stochastic process capable of producing bursting dynamics. Moreover, theoretical and experimental methods have also been developed to allow quantitative estimates of the associated biophysical parameters. These developments provide a new way to assess responses of living systems to SMFs. In this work, we report on our efforts to use single molecule fluorescence in situ hybridization to assess responses of NIH-3T3 cells to SMF exposure at flux densities ranging from 1 to 440 mT for 48 hours. Results will contribute to determining mechanisms by which SMF exposure influences gene expression.

Brady, Megan; Laramee, Craig

2013-03-01

200

Magnetic-field-induced singularities in spin-dependent tunneling through InAs quantum dots  

NASA Astrophysics Data System (ADS)

Current steps attributed to resonant tunneling through individual InAs quantum dots embedded in a GaAs-AlAs-GaAs tunneling device are investigated experimentally in magnetic fields up to 28 T. The steps evolve into strongly enhanced current peaks in high fields. This can be understood as a field-induced Fermi-edge singularity due to the Coulomb interaction between the tunneling electron on the quantum dot and the partly spin-polarized Fermi sea in the Landau quantized three-dimensional emitter.

Hapke-Wurst, I.; Zeitler, U.; Frahm, H.; Jansen, A. G. M.; Haug, R. J.; Pierz, K.

2000-11-01

201

Magnetic-field-induced enhancement of crystallinity and field-effect mobilities in phthalocyanine thin films  

NASA Astrophysics Data System (ADS)

Organic semiconductor thin films were fabricated by thermal deposition of free-base and metal phthalocyanines under a static magnetic field. A vertical magnetic field enhanced the crystallinity of the edge-on orientation of the phthalocyanine discs, whereas a horizontal magnetic field had a minimal effect on the crystallinity. The major factor for the orientation change is attributed to the diamagnetic anisotropies of ?-electrons in the phthalocyanine macrocycles. Field-effect transistors of phthalocyanine films fabricated under a vertical magnetic field exhibited better hole mobilities and on-current values with smaller threshold voltages than those of phthalocyanine films fabricated without a magnetic field.

Tabata, Kenichi; Sasaki, Takayuki; Yamamoto, Yohei

2013-07-01

202

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

PubMed

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

Celik, Mustafa Salih; Guven, Kemal; Akpolat, Veysi; Akdag, Mehmet Zulkuf; Naziroglu, Mustafa; Gul-Guven, Reyhan; Celik, M Yusuf; Erdogan, Sait

2013-02-28

203

Magnetic-field induced singlet-triplet phase transition in quasi one-dimensional organic superconductors  

Microsoft Academic Search

We propose a theoretical model of quasi-one-dimensional superconductors, with attractive electron-electron interactions dominant in the singlet d-wave channel and sub-dominant in the p-wave channel. We discuss, in the mean-field approximation, the effect of a magnetic field applied perpendicularly to the direction of the lowest conductivity. The lowest free energy phase corresponds to a singlet d-wave symmetry in low fields, but

N. Belmechri; G. Abramovici; M. Héritier; S. Haddad; S. Charfi-Kaddour

2007-01-01

204

Magnetic-field-induced semiconductor-semimetal transition in Bi-Sb alloys  

Microsoft Academic Search

Accurate and detailed measurements of the temperature dependence of the longitudinal magnetoresistance of single-crystal Bi-Sb alloys have been made, with static magnetic fields in the range 0 100 kG oriented parallel to the trigonal axis. Alloy concentrations were in the range 8 12 at.% Sb, and temperatures in the range 1 35 K. At very high fields the resistance increases

E. W. Fenton; J.-P. Jan; Å. Karlsson

1970-01-01

205

Two-channel R-matrix analysis of magnetic-field-induced Feshbach resonances  

SciTech Connect

A Feshbach resonance arises in cold atom scattering due to the complex interplay between several coupled channels. However, the essential physics of the resonance may be encapsulated in a simplified model consisting of just two coupled channels. In this paper we describe in detail how such an effective Feshbach model can be constructed from knowledge of a few key parameters, characterizing the atomic Born-Oppenheimer potentials and the low energy scattering near the resonance. These parameters may be obtained either from experiment or full coupled-channel calculations. Using R-matrix theory we analyze the bound state spectrum and the scattering properties of the two-channel model, and find it to be in good agreement with exact calculations.

Nygaard, Nicolai; Schneider, Barry I.; Julienne, Paul S. [Danish National Research Foundation Center for Quantum Optics, Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark); Physics Division, National Science Foundation, Arlington, Virginia 22230 (United States) and Electron and Optical Physics Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States); Atomic Physics Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899 (United States)

2006-04-15

206

Weak extremely-low-frequency magnetic field-induced regeneration anomalies in the planarian, Dugesia tigrina  

SciTech Connect

The authors recently reported that cephalic regeneration in the planarian Dugesia tigrina was significantly delayed in populations exposed continuously to combined parallel DC and AC magnetic fields. This effect was consistent with hypotheses suggesting an underlying resonance phenomenon. The authors report here, in a parallel series of investigations on the same model system, that the incidence of regeneration anomalies presenting as tumor-like protuberances also increases significantly (P < .001) in association with exposure to weak 60 Hz magnetic fields, with peak intensities ranging between 1.0 and 80.0 {micro}T. These anomalies often culminate in the complete disaggregation of the organism. Similar to regeneration rate effects, the incidence of regeneration anomalies is specifically dependent upon the planaria possessing a fixed orientation with respect to the applied magnetic field vectors. However, unlike the regeneration rate effects, the AC magnetic field alone, in the absence of any measurable DC field, is capable of producing these anomalies. Moreover, the incidence of regeneration anomalies follows a clear dose-response relationship as a function of AC magnetic field intensity, with the threshold for induced electric field intensity estimated at 5 {micro} V/m. The addition of either 51.1 or 78.4 {micro}T DC magnetic fields, applied in parallel combination with the AC field, enhances the appearance of anomalies relative to the 60 Hz AC field alone, but only at certain AC field intensities. Thus, whereas the previous study of regeneration rate effects appeared to involve exclusively resonance interactions, the regeneration anomalies reported here appear to result primarily from Faraday induction coupling.

Jenrow, K.A.; Smith, C.H.; Liboff, A.R. [Oakland Univ., Rochester, MI (United States). Dept. of Physics

1996-12-31

207

Magnetic-field-induced stress and magnetization in mechanically blocked Ni-Mn-Ga  

NASA Astrophysics Data System (ADS)

A single-crystal Ni-Mn-Ga sample (AdaptaMat, Ltd.) is first compressed from its longest shape to a given bias strain and subsequently subjected to a slowly alternating magnetic field while being prevented from deforming. The tests are repeated for several bias strains. The available blocking stress, or maximum field-induced stress relative to the bias stress, is critical for quantifying the work capacity of a material. The largest available blocking stress for this material is 1.47 MPa at a bias strain of 3% and field amplitude of 640 kA/m. The work capacity calculated as the area under the available blocking stress versus bias strain curve is 72.4 kJ/m3. An existing continuum thermodynamics model for Ni-Mn-Ga sensors is augmented by incorporating the magnetoelastic energy as a source of stress generation when the material is mechanically blocked. The strain and magnetization are described by fixing the variant volume fraction.

Sarawate, N. N.; Dapino, M. J.

2008-04-01

208

Observation of magnetic field-induced contraction of fission yeast cells using optical projection microscopy  

NASA Astrophysics Data System (ADS)

The charges in live cells interact with or produce electric fields, which results in enormous dielectric responses, flexoelectricity, and related phenomena. Here we report on a contraction of Schizosaccharomyces pombe (fission yeast) cells induced by magnetic fields, as observed using a phase-sensitive projection imaging technique. Unlike electric fields, magnetic fields only act on moving charges. The observed behavior is therefore quite remarkable, and may result from a contractile Lorentz force acting on diamagnetic screening currents. This would indicate extremely high intracellular charge mobilities. Besides, we observed a large electro-optic response from fission yeast cells.

Yang, Xi; Beckwith, A. W.

2005-03-01

209

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

NASA Astrophysics Data System (ADS)

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.

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

2013-10-01

210

The Magnetic Field Induced by the Solar Wind on the Dayside of Mars  

NASA Astrophysics Data System (ADS)

The Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) instrument on Mars Express can be used to measure the local magnetic field. The technique relies on the detection of the electron echoes. These are series of echoes that are equally spaced in time at the electron cyclotron period. The echoes are believed to be caused by the periodic return to the antenna of electrons that are accelerated during the sounder pulse by strong electric fields near the antenna. From the period of the echo, the magnetic field strength in the vicinity of the spacecraft can be computed. These scalar measurements are highly complementary to those obtained by the Mars Global Surveyor Magnetic Field Experiment (MAG/ER). The Cain et al. (2003) model is used for nightside magnetic field measurements where MARSIS data is from the dayside. The difference between the nightside and the dayside measurements is due to the electrical currents that flow in the dayside ionopause. An average magnetic field vector which is induced by the solar wind is calculated using a best-fit method for each periapsis pass. This result will contribute to the study of the Mars-solar wind interaction.

Akalin, F.; Gurnett, D. A.; Averkamp, T. F.; Kirchner, D. L.; Acuna, M. H.; Connerney, J. E.; Ness, N. F.; Plaut, J. J.; Picardi, G.

2007-12-01

211

Magnetic-field--induced surface transport on laser-irradiated foils  

Microsoft Academic Search

Electrons heated by absorption of laser energy are shown to generate intense magnetic fields which rapidly spread from the edge of the laser spot along the target surface. The fields convectively transport hot electrons and confine a major fraction of the deposited laser energy in the corona. Eventually, this energy is lost to fast-ion blowoff or deposited at large distances

D. W. Forslund; J. U. Brackbill

1982-01-01

212

Magnetic-Field-Induced Crossover to a Nonuniversal Regime in a Kondo Dot  

NASA Astrophysics Data System (ADS)

We have measured the magnetic splitting ?K of a Kondo peak in the differential conductance of a single-electron transistor while tuning the Kondo temperature TK along two different paths in parameter space: varying the dot-lead coupling at a constant dot energy and vice versa. At a high magnetic field B, the changes of ?K with TK along the two paths have opposite signs, indicating that ?K is not a universal function of TK. At low B, we observe a decrease in ?K with TK along both paths, in agreement with theoretical predictions. Furthermore, we find ?K/?<1 at low B and ?K/?>1 at high B, where ? is the Zeeman energy of the bare spin, in the same system.

Liu, Tai-Min; Hemingway, Bryan; Kogan, Andrei; Herbert, Steven; Melloch, Michael

2009-07-01

213

A magnetic field-induced crossover to a non-universal regime in a Kondo dot  

NASA Astrophysics Data System (ADS)

We have measured the magnetic splitting, ?K, of a Kondo peak in the differential conductance of a Single-Electron Transistor while tuning the Kondo temperature, TK, along two different paths in the parameter space: varying the dot-lead coupling at a constant dot energy, and vice versa. At a high magnetic field, B, the changes of ?K with TK along the two paths have opposite signs, suggesting that ?K is not a universal function of TK. At low B, we observe a decrease in ?K with TK along both paths. Detailed ?K(B) data for two different TK show consistency for the splitting onset. Furthermore, we find ?K/?<1 at low B and ?K/?>1 at high B, where ? is the Zeeman energy of the bare spin. We discuss an approximate scaling of ?K with B/TK at low B and compare the findings to previous measurements and theory.

Kogan, Andrei; Liu, Tai-Min; Hemingway, Bryan; Herbert, Steven; Melloch, Michael

2009-03-01

214

Magnetic Field-Induced Giant Enhancement of Electron-Phonon Energy Transfer in Strongly Disordered Conductors  

NASA Astrophysics Data System (ADS)

Relaxation of soft modes (e.g., charge density in gated semiconductor heterostructures, spin density in the presence of magnetic field) slowed down by disorder may lead to giant enhancement of energy transfer (cooling power) between overheated electrons and phonons at low bath temperature. We show that in strongly disordered systems with time-reversal symmetry broken by external or intrinsic exchange magnetic field the cooling power can be greatly enhanced. The enhancement factor as large as 102 at magnetic field B˜10T in 2D InSb films is predicted. A similar enhancement is found for the ultrasound attenuation.

Shtyk, A. V.; Feigel'man, M. V.; Kravtsov, V. E.

2013-10-01

215

One- and two-pulse quadrupolar excitation schemes of the ion motion in a Penning trap investigated with FT-ICR detection  

NASA Astrophysics Data System (ADS)

In a Penning ion trap the interconversion between the radial motional modes of stored particles can be accomplished by applying one- and two-pulse (Ramsey) azimuthal quadrupolar radio frequency fields. In this work the interaction of ions with the excitation fields has been probed by Fourier transform ion cyclotron resonance (FT-ICR) detection. A theoretical description of this interaction is derived by use of a quasi-classical coherent state and the interconversion of modes is interpreted in a quantum-mechanical context. The dipolar-detection FT-ICR signal at the modified cyclotron frequency has been studied as a function of the interaction parameters such as excitation frequency, amplitude and duration and is compared with the theoretical results.

Heck, M.; Blaum, K.; Cakirli, R. B.; Kretzschmar, M.; Marx, G.; Rodríguez, D.; Schweikhard, L.; Stahl, S.; Ubieto-Díaz, M.

2012-06-01

216

Ferroquadrupolar ordering in PrTi2Al20  

NASA Astrophysics Data System (ADS)

The origin of the nonmagnetic phase transition in PrTi2Al20, reported earlier in a macroscopic study, has been asserted microscopically using elastic and inelastic neutron scattering techniques. It has been shown spectroscopically that the crystalline-electric-field ground state is a nonmagnetic ?3 doublet, whereas the excited states are two triplets (?4 and ?5) and a singlet (?1). The diffraction experiment under external magnetic field shows that the nonmagnetic transition is indeed ferroquadrupolar ordering, which takes place as a consequence of cooperative removal of the ground-state-doublet degeneracy. It is therefore concluded that PrTi2Al20 is another rare example of Pr compounds exhibiting nonmagnetic quadrupolar order.

Sato, Taku J.; Ibuka, Soshi; Nambu, Yusuke; Yamazaki, Teruo; Hong, Tao; Sakai, Akito; Nakatsuji, Satoru

2012-11-01

217

Multiferroics with spiral spin orders.  

PubMed

Cross correlation between magnetism and electricity in a solid can host magnetoelectric effects, such as magnetic (electric) induction of polarization (magnetization). A key to attain the gigantic magnetoelectric response is to find the efficient magnetism-electricity coupling mechanisms. Among those, recently the emergence of spontaneous (ferroelectric) polarization in the insulating helimagnet or spiral-spin structure was unraveled, as mediated by the spin-exchange and spin-orbit interactions. The sign of the polarization depends on the helicity (spin rotation sense), while the polarization direction itself depends on further details of the mechanism and the underlying lattice symmetry. Here, we describe some prototypical examples of the spiral-spin multiferroics, which enable some unconventional magnetoelectric control such as the magnetic-field-induced change of the polarization direction and magnitude as well as the electric-field-induced change of the spin helicity and magnetic domain. PMID:20496385

Tokura, Yoshinori; Seki, Shinichiro

2010-04-12

218

Order Up  

ERIC Educational Resources Information Center

|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…

Gibeault, Michael

2005-01-01

219

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

PubMed

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

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

2011-08-18

220

Earth's magnetic field enabled scalar coupling relaxation of 13C nuclei bound to fast-relaxing quadrupolar 14N in amide groups  

NASA Astrophysics Data System (ADS)

Scalar coupling relaxation, which is usually only associated with closely resonant nuclei (e.g., 79Br-13C), can be a very effective relaxation mechanism. While working on hyperpolarized [5-13C]glutamine, fast liquid-state polarization decay during transfer to the MRI scanner was observed. This behavior could hypothetically be explained by substantial T1 shortening due to a scalar coupling contribution (type II) to the relaxation caused by the fast-relaxing quadrupolar 14N adjacent to the 13C nucleus in the amide group. This contribution is only effective in low magnetic fields (i.e., less than 800 ?T) and prevents the use of molecules bearing the 13C-amide group as hyperpolarized MRS/MRI probes. In the present work, this hypothesis is explored both theoretically and experimentally. The results show that high hyperpolarization levels can be retained using either a 15N-labeled amide or by applying a magnetic field during transfer of the sample from the polarizer to the MRI scanner.

Chiavazza, Enrico; Kubala, Eugen; Gringeri, Concetta V.; Düwel, Stephan; Durst, Markus; Schulte, Rolf F.; Menzel, Marion I.

2013-02-01

221

Competing Orders Under a Magnetic Field in URu_2Si_2  

NASA Astrophysics Data System (ADS)

URu_2Si2 is a model example of a heavy fermion system unstable to ordered phases created in the vicinity of a magnetic field-induced quantum critical point. At high temperatures (T> 6 K) or high magnetic fields (B> 39 T), the magnetic susceptibility and magnetoresistivity indicate clear signs of metamagnetism at BM 38 T, not unlike that observed in other heavy fermion systems such as CeRu_2Si2 and UPt_3, or the bilayer ruthenate system Sr_3Ru_2O_7. We choose to use the term ``itinerant electron metamagnetism'' because the metamagnetic transition or crossover is not caused by the destruction or creation of an ordered phase. A divergence of the Fermi liquid resistivity parameter A (where ?=?_0+AT^2) and vanishing of the Fermi liquid crossover temperature T on approach B BM and T= 0 both indicate a vanishing energy scale, qualitatively similar to that seen at antiferromagnetic quantum critical points. In contrast to CeRu_2Si_2, UPt3 and Sr_3Ru_2O_7, however, the metamagnetic quantum criticality in URu_2Si2 is unstable to the creation of multiple ordered phases at T< 6 K, perhaps assisted by the close proximity of the hidden order phase, which is destroyed at 35 T. Substitution of 4% Rh in place of one of the Ru atoms is sufficient to destroy the hidden order phase (at all magnetic fields) leading to a simpler phase diagram that consists of a single field-induced phase, which also may be created as a consequence of metamagnetic quantum criticality. In this case, evidence for a vanishing energy scale appears both at low and high magnetic fields, with conventional Fermi liquid behaviour restored inside the field-induced phase. Work supported by NSF, DOE and Florida State. Additional contributors include K.H.Kim, H.Amitsuka, M.Jaime & J.A.Mydosh.

Harrison, Neil

2004-03-01

222

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...

223

Ordering Game  

NSDL National Science Digital Library

This interactive game gives students practice in ordering sets of whole numbers, integers, fractions, decimals, and the sizes of circles. Students re-order a group of numbers or objects in a line from least to greatest by dragging them. The activity is timed and points are awarded.

2011-01-01

224

Apparatus for rapid adjustment of the degree of alignment of NMR samples in aqueous media: Verification with residual quadrupolar splittings in 23Na and 133Cs spectra  

NASA Astrophysics Data System (ADS)

NMR spectra of 23Na+ and 133Cs+ in gelatine in a silicone rubber tube that was stretched to various extents showed remarkably reproducible resonance multiplicity. The relative intensities of the components of the split peaks had ratios, 3:4:3, and 7:12:15:16:15:12:7, respectively, that conformed with those predicted using a Mathematica program. The silicone-rubber tube was sealed at its lower end by a small rubber stopper and placed inside a thick-walled glass tube. Gelatine was injected in solution into the silicone tube and ‘set’ by cooling below 30 °C. A plastic thumb-screw held the silicone tube at various degrees of extension, up to ˜2-fold. After constituting the gel in buffers containing NaCl and CsCl, both 23Na and 133Cs NMR spectroscopy revealed that after stretching the initial single Lorentzian line was split into a well-resolved triplet and a heptet, respectively. This was interpreted as being due to coupling between the electric quadrupoles of the nuclei and the average electric field gradient tensor of the collagen molecules of gelatine; these molecules became progressively more aligned in the direction of the main magnetic field, B0, of the vertical bore magnet, as the gel was stretched. This apparatus provides a simple way of demonstrating fundamental physical characteristics of quadrupolar cations, some characteristics of gelatine under stretching, and a way to invoke static distortion of red blood cells. It should be useful with these and other cell types, for studies of metabolic and membrane transport characteristics that may change when the cells are distorted, and possibly for structural studies of macromolecules.

Kuchel, Philip W.; Chapman, Bogdan E.; Müller, Norbert; Bubb, William A.; Philp, David J.; Torres, Allan M.

2006-06-01

225

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

SciTech Connect

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.

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

226

Ordering Fractions  

NSDL National Science Digital Library

This interactive Flash applet develops a student's fractional understanding and provides practice with comparing and ordering fractions. The learner is given five fractions in "frames" and must place them on the wall hooks in order from least to greatest. If help is needed, a student can enter the Testing Room and manipulate a pair of pipes to see and/or compare the two fractions side by side.

Bunker, Dan

2011-01-01

227

Imaging quadrupolar geophysical anomaly sources by 3D probability tomography: application to near-surface geoelectrical surveys  

NASA Astrophysics Data System (ADS)

We present the theory of the source quadrupole occurrence probability tomography method within a general approach including the source pole and source dipole occurrence probability tomographies, developed and amply discussed and tested in previous papers. In this new formulation, poles and dipoles still have the original meaning to represent centres and boundaries, respectively, of elementary bodies with constant constitutive parameters, while quadrupoles are assumed to simulate sharp corner elements. The purpose of quadrupole analysis is to improve the resolution power of geophysical methods, using once more probability as a suitable paradigm allowing all possible equivalent solutions to be included into a unique 3D tomography image. The new approach is described by first assuming that any geophysical field dataset can be hypothesized to be caused by a discrete number of source poles, dipoles and quadrupoles. Then, the previously published theory of the source pole and dipole occurrence probability tomography is symbolically extended to include source quadrupoles. Finally, the new formalism is explicitly written for the geoelectrical method, for which a few simple synthetic examples are discussed in order to demonstrate how the combined pole, dipole and quadrupole tomographies can provide a complete resolution of the most probable buried sources of the anomalies detected within a datum domain. A field example related to a geoelectrical survey carried out in the archaeological park of Pompei is presented, aiming at detecting remains of ancient Roman urbanization.

Alaia, Raffaele; Patella, Domenico; Mauriello, Paolo

2008-12-01

228

Ordering Decimals  

NSDL National Science Digital Library

This interactive Flash applet gives students practice in ordering decimals from lowest to highest in groups of 5 at a time. If help is needed, users can compare two decimals in the Testing Room by viewing them lined up with place names labeled.

Bunker, Dan

2011-01-01

229

Slow relaxation of longitudinal multispin orders in weakly and strongly coupled two-spin systems.  

PubMed

Longitudinal multispin order (LOMO) corresponds to a nonequilibrium population distribution in spin systems that exhibit scalar (J), dipolar, or quadrupolar coupling. We investigated the relaxation of longitudinal two-spin order (2-LOMO) in systems that had either weakly or strongly J-coupled spins. Our results indicated longer relaxation times for the 2-LOMO state compared with the corresponding longitudinal single-spin state (1-LOMO). Accessing nuclear spin states that have relaxation times longer than T(1), without the use of external contrast agents, is potentially useful for in vivo imaging and also for studying systems using dynamically hyperpolarized nuclear spins where longer life times are sought to increase the time available to study (bio)chemical events. PMID:22552892

D'Silva, Loyola; Pola, Arunima; Dutta, Prasanta; Martinez, Gary V; Sprenger, Peter; Gillies, Robert J; Kuchel, Philip W; Sendhil Velan, S

2012-05-02

230

Magnetic neutron diffraction study of the charge-ordered chain compounds Rb11Mn8O16 and Cs3Mn2O4  

NASA Astrophysics Data System (ADS)

The magnetic ordering patterns of Rb11Mn8O16 and Cs3Mn2O4 were determined by neutron powder diffraction with and without applied magnetic fields. The crystal structures of these compounds exhibit infinite chains of edge-sharing MnO4 tetrahedra with periodically alternating Mn2+ and Mn3+ valence. Both Rb11Mn8O16 and Cs3Mn2O4 show collinear magnetic order with antiferromagnetic alignment of Mn moments along the chains below the Néel temperatures TN = 38(1) and 13.5(5) K, respectively. In Cs3Mn2O4 the Mn2+ and Mn3+ moments could be separately refined. The full magnetic structure in a zero magnetic field can be viewed as a set of ferrimagnetic chains whose net moments are coupled antiferromagnetically perpendicular to the chain direction. For this compound, we further observe a magnetic field induced transition into a high-field phase with uniformly aligned ferrimagnetic moments.

Reehuis, M.; Señaris-Rodriguez, M. A.; Hoser, A.; Keimer, B.; Jansen, M.

2013-01-01

231

CORRIGENDUM: Fabrication and use of a nanoscale Hall probe for measurements of the magnetic field induced by MFM tips Fabrication and use of a nanoscale Hall probe for measurements of the magnetic field induced by MFM tips  

Microsoft Academic Search

In the published paper some references were missed. In line four of the last paragraph of page two after the word 'nanostructures' and before the right bracket should be added reference [11]. At the end of the caption for figure 3 should be added reference [12]. At the end of the caption for figure 4 should be added: 'The design

Victor N. Matveev; Vladimir I. Levashov; Vladimir T. Volkov; Oleg V. Kononenko; Anatoly V. Chernyh; Maxim A. Knjazev; Vyacheslav A. Tulin

2009-01-01

232

Resonant alteration of supercurrent in guiding structures with complex de Gennes distance and its magnetic-field-induced restoration  

NASA Astrophysics Data System (ADS)

Properties of the superconducting 2D disk and 3D wire are calculated within the framework of linearized Ginzburg-Landau theory with the complex de Gennes distance ? in the boundary condition. As a result, the self-adjointness of the Hamiltonian is lost, its eigenvalues E become complex too and the discrete bound states of the disk turn into the quasibound states with their lifetime defined by the eigeneneries imaginary parts Ei. Accordingly, the longitudinal supercurrent undergoes alteration with its attenuation/amplification being Ei-dependent too. It is shown that Ei as a function of the de Gennes imaginary part ?i exhibits a pronounced sharp extremum with its magnitude being the largest for the zero real part ?r of the de Gennes distance. Increasing magnitude of ?r quenches the Ei-?i resonance and at large ?r the eigenenergies E approach the asymptotic real values independent of the de Gennes length imaginary component. The extremum is also wiped out by the applied longitudinal uniform magnetic field. The finite lifetime of the disk quasibound states stems from the ?i-induced currents flowing through the superconductor boundary. The effect can be observed in the superconductors by applying to them the external electric field.

Olendski, Oleg

2011-03-01

233

Resonant alteration of propagation in guiding structures with complex Robin parameter and its magnetic-field-induced restoration  

NASA Astrophysics Data System (ADS)

Solutions of the scalar Helmholtz wave equation are derived for the analysis of the transport and thermodynamic properties of the two-dimensional disk and three-dimensional infinitely long straight wire in the external uniform longitudinal magnetic field B under the assumption that the Robin boundary condition contains extrapolation length ? with nonzero imaginary part ?i. As a result of this complexity, the self-adjointness of the Hamiltonian is lost, its eigenvalues E become complex too and the discrete bound states of the disk characteristic for the real ? turn into the corresponding quasibound states with their lifetime defined by the eigenenergies imaginary parts Ei. Accordingly, the longitudinal flux undergoes an alteration as it flows along the wire with its attenuation/amplification being Ei-dependent too. It is shown that, for zero magnetic field, the component Ei as a function of the Robin imaginary part exhibits a pronounced sharp extremum with its magnitude being the largest for the zero real part ?r of the extrapolation length. Increasing magnitude of ?r quenches the Ei - ?i resonance and at very large ?r the eigenenergies E approach the asymptotic real values independent of ?i. The extremum is also wiped out by the magnetic field when, for the large B, the energies tend to the Landau levels. Mathematical and physical interpretations of the obtained results are provided; in particular, it is shown that the finite lifetime of the disk quasibound states stems from the ?i-induced currents flowing through the sample boundary. Possible experimental tests of the calculated effect are discussed; namely, it is argued that it can be observed in superconductors by applying to them the external electric field E normal to the surface.

Olendski, O.

2011-06-01

234

Magnetic field induced transition in superconducting LaTiO3/SrTiO3 interfaces  

NASA Astrophysics Data System (ADS)

Superconductivity at the LaTiO3/SrTiO3 interface is studied by low temperature and high magnetic field measurements as a function of a back-gate voltage. We show that it is intimately related to the appearance of a low density (a few 1012 cm-2) of high mobility carriers, in addition to low mobility ones always present in the system. These carriers form superconducting puddles coupled by a metallic two-dimensional electron gas, as revealed by the analysis of the phase transition driven by a perpendicular magnetic field. Two critical fields are evidenced, and a quantitative comparison with a recent theoretical model is made.

Biscaras, J.; Bergeal, N.; Hurand, S.; Feuillet-Palma, C.; Rastogi, A.; Budhani, R. C.; Grilli, M.; Caprara, S.; Lesueur, J.

2013-07-01

235

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

NASA Astrophysics Data System (ADS)

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 the company Viewray aims to use 0.3 T. The magnetic field strength will affect the severity of magnetic field dose effects, such as the electron return effect (ERE): considerable dose increase at tissue air boundaries due to returning electrons. This paper has investigated how the ERE dose increase depends on the magnetic field strength. Therefore, four situations where the ERE occurs have been simulated: ERE at the distal side of the beam, the lateral ERE, ERE in cylindrical air cavities and ERE in the lungs. The magnetic field comparison values were 0.2, 0.75, 1.5 and 3 T. Results show that, in general, magnetic field dose effects are reduced at lower magnetic field strengths. At the distal side, the ERE dose increase is largest for B = 0.75 T and depends on the irradiation field size for B = 0.2 T. The lateral ERE is strongest for B = 3 T but shows no effect for B = 0.2 T. Around cylindrical air cavities, dose inhomogeneities disappear if the radius of the cavity becomes small relative to the in-air radius of the secondary electron trajectories. At larger cavities (r > 1 cm), dose inhomogeneities exist for all magnetic field strengths. In water-lung-water phantoms, the ERE dose increase takes place at the water-lung transition and the dose decreases at the lung-water transition, but these effects are minimal for B = 0.2 T. These results will contribute to evaluating the trade-off between magnetic field dose effects and image quality of MR-guided radiotherapy systems.

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

2008-02-01

236

Experimental studies on ultralow frequency pulsed gradient magnetic field inducing apoptosis of cancer cell and inhibiting growth of cancer cell  

Microsoft Academic Search

The morphology characteristics of cell apoptosis of the malignant tumour cells in magnetic field-treated mouse was observed\\u000a for the first time. The apoptotic cancer cell contracted, became rounder and divorced from adjacent cells; the heterochromatin\\u000a condensed and coagulated together along the inner side of the nuclear membrane; the endoplasmic reticulums (ER) expanded and\\u000a fused with the cellular membrane; many apoptotic

Fanqing Zeng; Congyi Zheng; Xinchen Zhang; Zongshan Li; Chaoyang Li; Chuanying Wang; Xinsong Zhang; Xiaoling Huang; Husheng Zhang

2002-01-01

237

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...

238

Resonant alteration of propagation in guiding structures with complex Robin parameter and its magnetic-field-induced restoration  

SciTech Connect

Highlights: > Solutions of the wave equation are analyzed for the confined circular geometry with complex Robin boundary conditions. > Sharp extremum is found in the energy dependence on the imaginary part of the extrapolation length. > Nonzero real part of the Robin length or/and magnetic field wipe out the resonance. - Abstract: Solutions of the scalar Helmholtz wave equation are derived for the analysis of the transport and thermodynamic properties of the two-dimensional disk and three-dimensional infinitely long straight wire in the external uniform longitudinal magnetic field B under the assumption that the Robin boundary condition contains extrapolation length {Lambda} with nonzero imaginary part {Lambda}{sub i}. As a result of this complexity, the self-adjointness of the Hamiltonian is lost, its eigenvalues E become complex too and the discrete bound states of the disk characteristic for the real {Lambda} turn into the corresponding quasibound states with their lifetime defined by the eigenenergies imaginary parts E{sub i}. Accordingly, the longitudinal flux undergoes an alteration as it flows along the wire with its attenuation/amplification being E{sub i}-dependent too. It is shown that, for zero magnetic field, the component E{sub i} as a function of the Robin imaginary part exhibits a pronounced sharp extremum with its magnitude being the largest for the zero real part {Lambda}{sub r} of the extrapolation length. Increasing magnitude of {Lambda}{sub r} quenches the E{sub i} - {Lambda}{sub i} resonance and at very large {Lambda}{sub r} the eigenenergies E approach the asymptotic real values independent of {Lambda}{sub i}. The extremum is also wiped out by the magnetic field when, for the large B, the energies tend to the Landau levels. Mathematical and physical interpretations of the obtained results are provided; in particular, it is shown that the finite lifetime of the disk quasibound states stems from the {Lambda}{sub i}-induced currents flowing through the sample boundary. Possible experimental tests of the calculated effect are discussed; namely, it is argued that it can be observed in superconductors by applying to them the external electric field E normal to the surface.

Olendski, O., E-mail: oolendski@ksu.edu.sa [King Abdullah Institute for Nanotechnology, King Saud University, P.O. Box 2454, Riyadh 11451 (Saudi Arabia)

2011-06-15

239

Fifty-hertz magnetic fields induce free radical formation in mouse bone marrow-derived promonocytes and macrophages  

Microsoft Academic Search

Our findings show a significant increase of free radical production after exposure to 50 Hz electromagnetic fields at a flux density of 1 mT to mouse bone marrow-derived (MBM) promonocytes and macrophages, indicating the cell-activating capacity of extremely low frequency magnetic fields (ELF-MF). We demonstrate that after exposure to ELF-MF mainly superoxide anion radicals were produced, both in MBM macrophages

Jana Rollwitz; Madeleine Lupke; Myrtill Simkó

2004-01-01

240

Pulsed Magnetic Field Induces Angiogenesis and Improves Cardiac Function of Surgically Induced Infarcted Myocardium in Sprague-Dawley Rats  

Microsoft Academic Search

Objective: It was the aim of this study to investigate the impact of pulsed magnetic field (PMF) on ischemic myocardium, though it has been reported that PMF treatment is a safe and effective method to facilitate bone and cutaneous wound healing. Methods: In this report, we describe a study in which 10 Hz 4 mT PMF and 15 Hz 6

Yuan Yuan; Liping Wei; Fei Li; Wenyi Guo; Weijie Li; Ronghua Luan; Anlin Lv; Haichang Wang

2010-01-01

241

Effects of T2-relaxation in MAS NMR spectra of the satellite transitions for quadrupolar nuclei: a 27Al MAS and single-crystal NMR study of alum KAl(SO4)2 · 12H2O  

NASA Astrophysics Data System (ADS)

Asymmetries in the manifold of spinning sidebands (ssbs) from the satellite transitions have been observed in variable-temperature 27Al MAS NMR spectra of alum (KAl(SO4)2 · 12H2O), recorded in the temperature range from -76 to 92 °C. The asymmetries decrease with increasing temperature and reflect the fact that the ssbs exhibit systematically different linewidths for different spectral regions of the manifold. From spin-echo 27Al NMR experiments on a single-crystal of alum, it is demonstrated that these variations in linewidth originate from differences in transverse (T2) relaxation times for the two inner (m = 1/2 ? m = 3/2 and m = -1/2 ? m = -3/2) and correspondingly for the two outer (m = 3/2 ? m = 5/2 and m = -3/2 ? m = -5/2) satellite transitions. T2 relaxation times in the range 0.5 3.5 ms are observed for the individual satellite transitions at -50 °C and 7.05 T, whereas the corresponding T1 relaxation times, determined from similar saturation-recovery 27Al NMR experiments, are almost constant (T1 = 0.07 0.10 s) for the individual satellite transitions. The variation in T2 values for the individual 27Al satellite transitions for alum is justified by a simple theoretical approach which considers the cross-correlation of the local fluctuating fields from the quadrupolar coupling and the heteronuclear (27Al 1H) dipolar interaction on the T2 relaxation times for the individual transitions. This approach and the observed differences in T2 values indicate that a single random motional process modulates both the quadrupolar and heteronuclear dipolar interactions for 27Al in alum at low temperatures.

Andersen, Morten Daugaard; Jakobsen, Hans J.; Skibsted, Jørgen

2005-04-01

242

Relationships between lipid membrane area, hydrophobic thickness, and acyl-chain orientational order. The effects of cholesterol.  

PubMed Central

A microscopic interaction model for a fully hydrated lipid bilayer membrane containing cholesterol is used to calculate, as a function of temperature and composition, the membrane area, the membrane hydrophobic thickness, and the average acyl-chain orientational order parameter, S. The order parameter, S, is related to the first moment, M1, of the quadrupolar magnetic resonance spectrum which can be measured for lipids with perdeuterated chains. On the basis of these model calculations as well as recent experimental measurements of M1 using magnetic resonance and of membrane area using micromechanical measurements, a discussion of the possible relationships between membrane area, hydrophobic thickness, and moments of nuclear magnetic resonance spectra is presented. It is pointed out that S under certain circumstances may be useful for estimating the hydrophobic membrane thickness. This is particularly advantageous for multicomponent membranes where structural data are difficult to obtain by using diffraction techniques. The usefulness of the suggested relationships is demonstrated for cholesterol-containing bilayers.

Ipsen, J H; Mouritsen, O G; Bloom, M

1990-01-01

243

Precision search for magnetic order in the pseudogap regime of La2-xSrxCuO4 by muon spin relaxation  

NASA Astrophysics Data System (ADS)

We report a high-precision search for orbital-like magnetic order in the pseudogap region of La2-xSrxCuO4 single crystals using zero-field muon spin relaxation (ZF-?SR). In contrast to previous studies of this kind, the effects of the dipolar and quadrupolar interactions of the muon with nearby nuclei are calculated. ZF-?SR spectra with a high number of counts were also recorded to determine whether a magnetically ordered phase exists in dilute regions of the sample. Despite these efforts, we find no evidence for static magnetic order of any kind in the pseudogap region above the hole-doping concentration p=0.13.

Huang, W.; Pacradouni, V.; Kennett, M. P.; Komiya, S.; Sonier, J. E.

2012-03-01

244

First Order Paths in Ordered Trees  

Microsoft Academic Search

We give two sucient conditions on XPath like languages for having first order expressivity, meaning that every first order defin- able set of paths in an ordered node-labeled tree is definable in that XPath language. They are phrased in terms of expansions of naviga- tional (sometimes called \\

Maarten Marx

2005-01-01

245

Authorize Compound Orders  

Cancer.gov

Home What's New Discovery Development Pathways Grants/Contracts Site Search Data Search NCI View Status / Authorize Orders Authorized representatives: Authorize Compound Orders If you ordered compounds from the DTP and wish to view the status of your

246

High-order vibration modes of bimetallic Ag-Au nanoparticles embedded in glass  

Microsoft Academic Search

High-resolution low-frequency Raman scattering measurements from embedded AgAu nanoparticles unveil efficient scattering by harmonics of both the quadrupolar and the spherical modes. Comparing the experimental data with theoretical calculations that account for both the embedding medium and the resonant Raman process enables a very complete description of the observed multiple components in terms of harmonics of both the quadrupolar and

S. Adichtchev; S. Sirotkin; G. Bachelier; L. Saviot; S. Etienne; B. Stephanidis; E. Duval; A. Mermet

2009-01-01

247

a Study of Orientational Ordering in Solid Deuterium  

NASA Astrophysics Data System (ADS)

Nuclear magnetic resonance (NMR) studies were performed on samples of solid Deuterium with para concentrations X in the range 0.05 < X < 0.07 at temperatures between 0.032K and 3.0K and at a Larmor frequency of 5.88 MHz. This range of temperatures and concentrations includes the first order transition to the long range orientational ordered state. The spin-lattice relaxation times for both ortho (I = 2) and para (I = 1) D(,2) species were measured by the intensity of solid echos generated by the pulse sequence 90(,0)-t-90(,0)-150(mu)s-90(,90). In addition, the solid echoes themselves were digitized which, through the use of the fast Fourier transform, provided both the lineshapes of the two species, and the secondmoments M(,2) of their absorption lines. The secondmoments and relaxation times for both species are reported as functions of temperature at concentrations X = 0.05, 0.33, 0.46, 0.56 in the disordered phase, and for concentrations X = 0.65 and 0.70 which are above the concentration at which the long range order transition is observed. The results are discussed in terms of existing models (Washburn, 1983b) of spin-lattice relaxation in solid H(,2). At all concentrations below which the transition to a long range ordered phase does not occur (X < 0.58), the temperature dependence of the lineshape, secondmoment, and spin-lattice relaxation times is quite smooth. This finding is in agreement with the results of Candela (1983) and does not support the contention of some investigators (Sullivan, 1978, 1979) (Cochran, 1980) that at low temperatures in this concentration range D(,2) undergoes a phase transition to a "quadrupolar glass" phase. The relaxation times for T < 0.5K in the long range ordered phase (X > 0.59) seem to suggest the emergence of a mechanism providing intrinsic spin-lattice relaxation for the ortho molecules. Previous measurements in the cubic phase have been confined to higher temperatures, and measurements at comparable temperatures have been confined to concentrations below X(,c). No previous evidence for such a mechanism has been reported. A mechanism closely related to the spin-lattice relaxation mechanism for the ortho-D(,2) system is proposed to account for this intrinsic relaxation in the para-D(,2) system.

Calkins, Myron Eugene, Jr.

248

Mean residual life ordering  

Microsoft Academic Search

A new partial ordering among life distributions in terms of their mean residual life is introduced. This ordering is weaker\\u000a than the hazard rate ordering but it is stronger than the variability ordering. Characterizations of the DMRL and NBUE distribution\\u000a are given.

Abdulhamid A. Alzaid

1988-01-01

249

Thermo-magnetic history effects in the giant magnetostriction across the first-order transition and minor hysteresis loops modeling in Fe0.955Ni0.045Rh alloy  

NASA Astrophysics Data System (ADS)

Results of temperature- and magnetic field-dependent strain measurements across the first-order antiferromagnetic to ferromagnetic phase transition in Fe0.955Ni0.045Rh are presented. Distinct thermal and magnetic field hystereses are observed in the measured strain across the phase transition. The minor hysteresis loops inside the hysteretic regime across the temperature-driven transition are modeled using the Preisach model of hysteresis. The applicability of the Preisach model to explain the general features of minor hysteresis loops is discussed for a disorder influenced first-order transition. The minor hysteresis loops show the property of retaining the memory of the starting or end point of the temperature cycle followed within the hysteretic region. A larger temperature excursion within the hysteretic region wipes out the memory of a smaller temperature cycle which contains one of the extrema of the larger cycle. The end-point memory and the wiping-out property of the minor hysteresis loops can be described quite well within the Preisach model, irrespective of the temperature history followed to reach a particular starting point. Thermo-magnetic history effects across the magnetic field-induced transition are explained, which will enable the choice of the starting point of an experimental cycle in the field-temperature phase space so as to achieve the desired functionality. Our results highlight the necessity to understand the influence of disorder on a first-order phase transition so as to achieve a repeatable performance of materials whose functionalities are based on such a transition.

Manekar, Meghmalhar; Sharma, V. K.; Roy, S. B.

2012-05-01

250

Higher order phantom maps  

Microsoft Academic Search

For each ordinal number , we dene phantom maps of order . We construct universal phantom maps out ofX with order, and show that under easily veriable condi- tions, every one of these universal phantom maps is essential.

JEFFREY STROM

2003-01-01

251

Capacity: Compare and Order  

NSDL National Science Digital Library

Students are given four containers and asked to order them from the container that holds the least to the container that holds the most, first by predicting the order, and then by measuring to test their predictions.

Cornwell, Susan

2010-07-23

252

Pharmakon Laboratory Order  

Center for Drug Evaluation (CDER)

Text Version... proposed orders.5 The Court has now had an opportunity to review the parties' proposed injunctive orders and their responses ... More results from www.fda.gov/downloads/drugs/guidancecomplianceregulatoryinformation

253

Ordered Semantic Hyper Tableaux  

Microsoft Academic Search

A family of tableau methods, called ordered semantic hyper (OSH) tableau methods for first-order theories with function symbols, is presented. These methods permit semantic information to guide the search for a proof. They also may make use of orderings on literals, clauses, and interpretations to guide the search. In a typical tableau, the branches represent conjunctions of literals, and the

Adnan Yahya; David A. Plaisted

2002-01-01

254

Aggregating Partially Ordered Preferences  

Microsoft Academic Search

Preferences are not always expressible via complete linear orders: some- times it is more natural to allow for the presence of incomparable outcomes. This may hold both in the agents' preference ordering and in the social order. In this paper we consider this scenario and we study what properties it may have. In par- ticular, we show that, despite the

Maria Silvia Pini; Francesca Rossi; Kristen Brent Venable; Toby Walsh

2009-01-01

255

Higher Order Entropies  

NASA Astrophysics Data System (ADS)

Higher order entropies are kinetic entropy estimators for fluid models. These quantities are quadratic in the velocity and temperature derivatives and have temperature dependent coefficients. We investigate governing equations for higher order entropies and related a priori estimates in the natural situation where viscosity and thermal conductivity depend on temperature. We establish positivity of higher order derivative source terms in these governing equations provided that || log T||_{BMO}+||v/sqrt{T}||Linfty is small enough. The temperature factors renormalizing temperature and velocity derivatives then yield majorization of lower order convective terms only when the temperature dependence of transport coefficients is taken into account according to the kinetic theory. In this situation, we obtain entropic principles for higher order entropies of arbitrary order. As an application, we investigate a priori estimates and global existence of solutions when the initial values log( T 0/ T ?) and v_0/sqrt{T}0 are small enough in appropriate spaces.

Giovangigli, Vincent

2008-02-01

256

Characterizing limit order prices  

NASA Astrophysics Data System (ADS)

A computational model of a limit order book is used to study the effect of different limit order distribution offsets. Reference prices such as same side/contra side best market prices and last traded price are considered in combination with different price offset distributions. We show that when characterizing limit order prices, varying the offset distribution only produces different behavior when the reference price is the contra side best price. Irrespective of the underlying mechanisms used in computing the limit order prices, the shape of the price graph and the behavior of the average order book profile distribution are strikingly similar in all the considered reference prices/offset distributions. This implies that existing averaging methods can cancel variabilities in limit order book shape/attributes and may be misleading.

Withanawasam, R. M.; Whigham, P. A.; Crack, Timothy Falcon

2013-11-01

257

Learning to Order Things  

Microsoft Academic Search

There are many applications in which it is desirable to order rather than classify instances. Here we consider the problem of learning how to order, given feedback in the form of preference judgments, i.e., statements to the effect that one instance should be ranked ahead of another. We outline a two-stage approach in which one first learns by conventional means

William W. Cohen; Robert E. Schapire; Yoram Singer

1999-01-01

258

Ferroelectricity from magnetic order  

Microsoft Academic Search

Magnetic insulators with competing exchange interactions can give rise to strong fluctuations and qualitatively new ground states. The proximity of such systems to quantum critical points can lead to strong cross-coupling between magnetic long-range order and the chemical lattice. Case in point is a new class of multiferroic materials in which the magnetic and ferroelectric order parameters are directly coupled,

Michel Kenzelmann

2009-01-01

259

Compare and Order Fractions  

NSDL National Science Digital Library

In this 7-minute video, users learn how to compare and order fractions. The video shows visual representations and guides the learner through steps for comparing and ordering like-denominator fractions, unit fractions, and fractions with unlike denominators (by using equivalent fractions).

2011-01-01

260

Exploring Order of Operations  

NSDL National Science Digital Library

This interactive activity demonstrates the order of operations. The game asks students to click on the correct operation in a series of mathematical problems. Correct answers will increase the user's time for the next game. Students should have some knowledge of the order of operations prior to doing this activity. Two worksheets are also available for print or download in PDF file format.

2012-08-06

261

The interval ordering problem  

Microsoft Academic Search

For a given set of intervals on the real line, we consider the problem of ordering the intervals with the goal of minimizing an objective function that depends on the exposed interval pieces (that is, the pieces that are not covered by earlier intervals in the ordering). This problem is motivated by an application in molecular biology that concerns the

Christoph Dürr; Maurice Queyranne; Frederik Spieksma; Fabrice Talla Nobibon; Gerhard Woeginger

2010-01-01

262

Narcissism and birth order.  

PubMed

The purpose of this investigation was to clarify the relationship between birth-order position and the development of narcissism, while refining research and theory. The relationship between birth-order status and narcissism was examined with a sample of 79 undergraduate students (55 women and 24 men). These subjects were placed in one of the four following birth-order categories of firstborn, second-born, last-born, and only children. These categories were chosen given their significance in Adlerian theory. Each subject completed the Narcissistic Personality Inventory and a demographic inventory. Based on psychodynamic theory, it was hypothesized that firstborn children were expected to score highest, but statistical significance was not found for an association between narcissism and birth order. Further research is urged to investigate personality theory as it relates to parenting style and birth order. PMID:9148293

Eyring, W E; Sobelman, S

1996-04-01

263

Molecular order and hydration property of amine group in phosphatidylethanolamine and its N-methyl derivatives at subzero temperatures.  

PubMed Central

The molecular order and hydration properties of the amine group in phosphatidylethanolamine and its N-methyl derivatives were studied by 2H-NMR at subzero temperatures. Three coexisting signals with 2H-NMR quadrupolar splittings of 146, 106, and 28.8 KHz were detected from the fully hydrated phosphatidylethanolamine/D2O at the lowest studied temperature of -120 degrees C by using short recycle time in the applied NMR pulse sequence. These signals have been assigned to originate from frozen D2O in the interbilayer space and the deuterated amine group, i.e., -ND, with and without threefold symmetric motions. Comparative 2H-NMR studies of phosphatidylethanolamine/D2O with different degrees of methylation over a temperature range between -40 and -120 degrees C lead to the following conclusions. First, the bond angle of -D attached to the nitrogen atom of the amine group may be determined by the 2H-NMR quadrupolar splittings, i.e., 106 and 28.8 KHz, of the two coexisting signals of the deuterated amine group and found to be 112.9 for the gel-state phosphatidylethanolamine. Second, assuming the applicability of the empirical equation for the hydrogen bond distance of N+D--O with deuteron quadrupole coupling constants and using the intermolecular hydrogen bond distance of the amine group determined in single crystals of phosphatidylethanolamine bilayers, the largest measured quadrupolar splitting (delta nu Q) of N-D in this study, i.e., 106 KHz, is close to the static value. This interpretation is also consistent with the fact that the delta nu Q value determined remains constant in the temperature range between -70 and -120 degrees C. Third, the molecular order parameter of the amine group, as calculated from the ratio of the libration-averaged and static delta nu Q value for the lipid with different degrees of methylation, suggests that the perturbation of the headgroup interaction is most significant for the final methylation step. Finally, measurement of the spectral intensity of isotropic unfrozen D2O signals in D2O/phospholipid dispersions at temperatures below the homogeneous nucleation temperature of ice formation for D2O, i.e., below -34 degrees C, suggests that the first methylation step perturbs the neighboring water most significantly. Assuming that the molecular order of the amine group and the amount of unfrozen water detected under the present experimental condition can be taken as a measure of the hydrogen-bonding ability and the extent of perturbation caused by the methyl group, respectively, the gradual methylation of the amine group perturbs the interactions of the N-methylated headgroups in a nonlinear fashion. The results provide a molecular explanation for the phase behavior of phospholipids with different degrees of methylation.

Hsieh, C H; Wu, W G

1995-01-01

264

Programming Languages: Marching Orders  

NSDL National Science Digital Library

In this activity about computer programming, learners follow instructions in a variety of ways in order to successfully draw figures. Through these exercises, learners will experience some of the often frustrating aspects of computer programming.

Bell, Tim; Witten, Ian; Fellows, Mike; Adams, Robyn; Mckenzie, Jane

2005-01-01

265

Forms order entry system  

US Patent & Trademark Office Database

An order entry system is provided comprising a first computer system, a printing station computer system, a form design repository, a second computer system, a validation engine, and a pricing engine. The first computer system captures form design data and the second computer generates a form price, validates the form, and transmits a validated and priced order to the printing station computer system. The second computer is also programmed to store an index of form design files in the form design repository. The forms order entry system is also programmed to determine manufacturability of an ordered form by comparing its form design data to a set of validation rules and route manufacturability exceptions to a selected one of a plurality of exception handling locations. The pricing engine determines identified labor, material, burden, and mark-up cost components, and applies a set of pricing rules to them, to enable calculation of a form price.

Morscheck; William F. (Franklin, OH); Miller; Kenneth W. (Tipp City, OH); Ryan; Thomas J. (Trotwood, OH); Ohlemacher; David M. (Dayton, OH); Russell; C. Thomas (Springboro, OH); Burgbacher; Mark A. (Mason, OH); Schweikert; Christopher L. (Cincinnati, OH)

2000-06-13

266

Ordering for Positive Dependence.  

National Technical Information Service (NTIS)

A partial ordering for positive dependent bivariate distributions is introduced. The main result shows that tests of independence based on rank statistics such as Spearman's rho, Kendall's tau, Fisher-Yates' normal score statistic, vander Waerden's statis...

B. F. Schriever

1986-01-01

267

Ordering the braid groups  

Microsoft Academic Search

We give an explicit geometric argument that Artin's braid group $B_n$ is right-orderable. The construction is elementary, natural, and leads to a new, effectively computable, canonical form for braids which we call left-consistent canonical form. The left-consistent form of a braid which is positive (respectively negative) in our order has consistently positive (respectively negative) exponent in the smallest braid generator

Roger Fenn; Michael T Greene; Dale Rolfsen; Colin Rourke; Bert Wiest

1998-01-01

268

Compare and Order  

NSDL National Science Digital Library

This interactive Flash applet helps students learn to compare and order objects according to size and weight attributes. The text and voice prompts ask students to compare three objects to find the longest, tallest, shortest, and so on. It then asks them to place three objects in a specified order, such as narrowest to widest. Correct responses are rewarded with a cheer and a summary of the results. One concern for users might be the British accents of the readers.

Bunker, Amanda H.

2004-01-01

269

Pulsed magnetic field induced "analgesia" in the land snail, Cepaea nemoralis, and the effects of mu, delta, and kappa opioid receptor agonists/antagonists.  

PubMed

A brief exposure to a pulsed magnetic field (Cnp: patent pending) had significant antinociceptive or "analgesic" effects in the land snail, Cepaea nemoralis, as evidenced by an increase in the latency of response to a warmed (40 degrees C) surface. This analgesia was in part opioid mediated being significantly reduced, but not eliminated: by the prototypic opiate antagonist, naloxone; the mu (mu) opioid receptor directed antagonists, naloxazine or beta-funaltrexamine, and the delta (delta) opioid receptor directed antagonists, naltrindole-5'-isothiocyanate or ICI 174,864. However the Cnp induced analgesia was unaffected by the kappa (kappa) opioid receptor directed antagonist, nor-binaltorphimine. The delta 1 and delta 2 opioid receptor directed agonists, (DPDPE, [D-Pen2,D-Pen5]enkephalin), (deltorphin, [D-Ala2,Glu4]), respectively, also had significant differential analgesic effects, supporting a functional delta opioid receptor mediated enkephalinergic mechanism in Cepaea. These results suggest that this specific pulsed magnetic field (Cnp) elicits significant analgesic effects through mechanisms that, in part, involve delta and, to a lesser extent mu opioid receptors. PMID:9213364

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

1997-01-01

270

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

SciTech Connect

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.

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

1999-05-25

271

Magnetic-field induced crossover of superconducting percolation regimes in the layered organic Mott system {kappa}-(BEDT-TTF){sub 2}Cu[N(CN){sub 2}]Cl.  

SciTech Connect

Fluctuation spectroscopy is used to investigate the organic bandwidth-controlled Mott system {kappa}-(BEDT-TTF){sub 2}Cu[N(CN){sub 2}]Cl. We find evidence for percolative-type superconductivity in the spatially inhomogeneous coexistence region of antiferromagnetic insulating and superconducting states. When the superconducting transition is driven by a magnetic field, percolation seems to be dominated by instable superconducting clusters upon approaching T{sub c}(B) from above, before a 'classical' type of percolation is resumed at low fields, dominated by the fractional change of superconducting clusters. The 1/f noise is resolved into Lorentzian spectra in the crossover region, where the action of an individual fluctuator is enhanced, pointing to a mesoscopic phase separation.

Mueller, J.; Brandenberg, J.; Schlueter, J. A.; Materials Science Division; Max Planck Inst. for Chemical Physics of Solids

2009-01-01

272

Magnetic-field-induced structural change of a two-dimensional colloid of glycerol droplets on a nematic liquid-crystal surface  

NASA Astrophysics Data System (ADS)

The structural changes of a two-dimensional colloidal crystal, consisting of glycerol droplets on a nematic liquid-crystal surface, due to a magnetic field applied parallel to the liquid-crystal surface, were observed and analyzed. The hexagonal lattice arrangement of glycerol droplets transformed into a smaller, anisotropic hexagonal-like lattice when the magnetic field was applied. The intermediate stage of the transition is influenced by the way in which the magnetic field is applied. When a sufficiently strong magnetic field is applied directly, the transition proceeds by passing through a random arrangement and then through a chainlike arrangement. With a gradually increasing magnetic field, the transition starts locally and extends throughout the entire region. The relaxation processes that occur once the field is switched off are very similar, irrespective of the manner in which the field is switched off. The relaxation begins at the outside and then extends to the central regions. No tendency to form a chainlike arrangement was observed during the relaxation process. The processes during switching on and off demonstrate a hysteresis with respect to the magnetic field strength.

Paek, Sang-In; Kim, Song-Jo; Kim, Jong-Hyun

2013-03-01

273

Pressure-induced enhancement of the transition temperature of the magnetic-field-induced superconducting state in ?- (BETS)2 Fe Cl4  

NASA Astrophysics Data System (ADS)

The effect of a small hydrostatic pressure p?1.4kbar on the temperature-magnetic field phase diagram of the organic conductor ?-(BETS)2FeCl4 is reported. At zero field a hysteretic superconducting (Tc?5.6K) to antiferromagnetic insulator transition (TN?4K) is found. Furthermore, the transition temperature to the field-induced superconducting (FISC) state, as well as its concomitant upper critical field, is found to increase by ˜33% . The phase diagram of the FISC state for both pressures is well described in terms of the Jaccarino-Peter effect if the interactions among quasiparticles is taken into account.

Balicas, L.; Barzykin, V.; Storr, K.; Brooks, J. S.; Tokumoto, M.; Uji, S.; Tanaka, H.; Kobayashi, H.; Kobayashi, A.

2004-09-01

274

LETTER TO THE EDITOR: Side-by-side existence of the quantum Hall effect and the magnetic-field-induced metal-insulator transition  

Microsoft Academic Search

The authors report on a study of magnetotransport in a sheet of Si-donor impurities in MBE-grown GaAs. For densities in the 1012 cm-2 range both the quantum Hall effect and magnetic freeze out are shown to occur. They point out the possibility of tuning the onset of the magnetic freeze out with respect to a given magnetic filling factor by

A. Zrenner; F. Koch; J. Leotin; M. Goiran; K. Ploog

1988-01-01

275

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

NASA Astrophysics Data System (ADS)

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.

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

276

Exposure to Extremely Low Frequency Magnetic Fields Induces Fos-Related Antigen-Immunoreactivity Via Activation of Dopaminergic D1 Receptor  

PubMed Central

We previously demonstrated that repeated exposure to extremely low frequency magnetic fields (ELF-MF) increases locomotor activity via stimulation of dopaminergic D1 receptor (J. Pharmacol. Sci., 2007;105:367-371). Since it has been demonstrated that activator protein-1 (AP-1) transcription factors, especially 35-kDa fos-related antigen (FRA), play a key role in the neuronal and behavioral adaptation in response to various stimuli, we examined whether repeated ELF-MF exposure induces FRA-immunoreactivity (FRA-IR) in the striatum and nucleus accumbens (striatal complex) of the mice. Repeated exposure to ELF-MF (0.3 or 2.4 mT, 1 h/day, for consecutive fourteen days) significantly induced hyperlocomotor activity and FRA-IR in the striatal complex in a field intensity-dependent manner. ELF-MF-induced FRA-IR lasted for at least 1 year, while locomotor activity returned near control level 3 months after the final exposure to ELF-MF. Pretreatment with SCH23390, a dopaminergic D1 receptor antagonist, but not with sulpiride, a dopaminergic D2 receptor antagonist, significantly attenuated hyperlocomotor activity and FRA-IR induced by ELF-MF. Our results suggest that repeated exposure to ELF-MF leads to prolonged locomotor stimulation and long-term expression of FRA in the striatal complex of the mice via stimulation of dopaminergic D1 receptor.

Shin, Eun-Joo; Nguyen, Xuan-Khanh Thi; Nguyen, Thuy-Ty Lan; Pham, Diem-Thu

2011-01-01

277

Influence of Temperature during Electric- and Magnetic-Field-Induced Alteration of Calcium-Ion Release from In vitro Brain Tissue.  

National Technical Information Service (NTIS)

A technique based on release of calcium ions from in vitro preparations of avian brain tissues has been used by several investigators to demonstrate a biological effect of weak electric and magnetic fields. When the tissues have been exposed to ELF-modula...

C. F. Blackman S. G. Benane D. E. House

1991-01-01

278

Concomitant Ordering and Symmetry Lowering  

ERIC Educational Resources Information Center

|Examples of concomitant ordering include magnetic ordering, Jahn-Teller cooperative ordering, electronic ordering, ionic ordering, and ordering of partially-filled sites. Concomitant ordering sets in when a crystal is cooled and always lowers the degree of symmetry of the crystal. Concomitant ordering concepts can also be productively applied to…

Boo, William O. J.; Mattern, Daniell L.

2008-01-01

279

Sympathy and Social Order  

ERIC Educational Resources Information Center

Social order is possible only if individuals forgo the narrow pursuit of self-interest for the greater good. For over a century, social scientists have argued that sympathy mitigates self-interest and recent empirical work supports this claim. Much less is known about why actors experience sympathy in the first place, particularly in fleeting…

Irwin, Kyle; McGrimmon, Tucker; Simpson, Brent

2008-01-01

280

Reviving Partial Order Planning  

Microsoft Academic Search

This paper challenges the prevailing pessimism about the scalability of partial order planning (POP) algorithms by presenting several novel heuristic control techniques that make them competitive with the state of the art plan syn- thesis algorithms. Our key insight is that the techniques responsible for the efficiency of the currently success- ful planners-viz., distance based heuristics, reachability analysis and disjunctive

Xuanlong Nguyen; Subbarao Kambhampati

2001-01-01

281

Second-order elections  

Microsoft Academic Search

The composition of the directly elected European Parliament does not precisely reflect the ‘real’ balance of political forces in the European Community. As long as the national political systems decide most of what there is to be decided politically, and everything really important, European elections are additional national second-order elections. They are determined more by the domestic political cleavages than

Karlheinz Reif; Hermann Schmitt

1997-01-01

282

Central Authority and Order  

Microsoft Academic Search

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.

Emily Erikson; Joseph M. Parent

2007-01-01

283

Land and World Order.  

ERIC Educational Resources Information Center

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…

Mische, Patricia, Ed.; And Others

1982-01-01

284

First Order Marked Types  

Microsoft Academic Search

We present a simple notion of marking of first order formulas, which enables to optimize program extraction from intuitionistic Natural Deduction proofs. It gives a way to mark some parts of a proof depending on the marking of its conclusion. Thus it allows to remove useless code from the extracted -terms. We define a notion of realizability by which we

Philippe Curtain

1995-01-01

285

Order without design  

Microsoft Academic Search

Experimental reality in molecular and cell biology, as revealed by advanced research technologies and methods, is manifestly inconsistent with the design perspective on the cell, thus creating an apparent paradox: where do order and reproducibility in living systems come from if not from design? I suggest that the very idea of biological design (whether evolutionary or intelligent) is a misconception

Alexei Kurakin

2010-01-01

286

Land and World Order.  

ERIC Educational Resources Information Center

|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…

Mische, Patricia, Ed.; And Others

1982-01-01

287

Paraparticles of Infinite Order  

NASA Astrophysics Data System (ADS)

We show that with one exception every possible statistical type of particle consistent with the cluster properties of quantum mechanics can be uniquely identified by a single pair of integers (p, q). A particle of type (p, q) has states corresponding to all Young diagrams whose first p columns (and only these) have arbitrary depth and whose first q rows (and only these) have arbitrary length. Parabosons and parafermions of order p are included in this scheme as types (0, p) and (p, 0), respectively. If p and q are nonzero, then the particle is of infinite order. The only exception to this classification scheme is a particle with states corresponding to all Young diagrams.

Hartle, James B.; Stolt, Robert H.; Taylor, John R.

1970-10-01

288

Mrs. Asuman's emergency order.  

PubMed

The Family Planning Management Development Project presents a case scenario for family planning manager training and group discussion. The manager of a family planning clinic, Mrs. Asuman, notes that the demand for condoms has increased about 3-fold in the last 3 months. The Ministry of Health's condom promotional radio campaign, which began 2 months ago, is probably responsible for the increase. Clinic staff did not know about the campaign when they made their last order 2 months ago. The supplies of condoms are lower than the minimum level and the next routine ordering time is in another month. The supervising nurse comments that other clinics have the same problem, presumably due to the radio campaign. She inspects the storeroom, cartons of contraceptives and their expiration dates, and puts monthly tallies from the stock cards for each type of contraceptive on the Contraceptive Data Analysis Charts. This activity confirms the increase in demand for condoms. If the demand rate increases at the current rate, the clinic will be out of condoms in 2 weeks, the same amount of time it takes for an emergency order to arrive. Using the Max/Min System, and based on the demand in August, the supervising nurse and Mrs. Asuman calculate the average monthly consumption of condoms, which translates into a 4.1 months' supply. This should meet client demand until the next order arrives in February. Mrs. Asuman needs to closely monitor the number of condoms distributed for the next few months until demand stabilizes to determine whether the high demand for condoms continues at the high rate. The project presents questions on this case for group discussion. It also provides a case worksheet for this case study so family planning managers undergoing training can learn the Max/Min system. It includes sample worksheets of the Contraceptive Data Analysis Chart and an answer sheet. PMID:12319219

289

Order of Operations Four  

NSDL National Science Digital Library

This interactive Java applet, based on the familiar game Connect Four, gives students practice in applying order of operations. Two players take turns evaluating expressions involving the four basic operations (addition, subtraction, multiplication and division). If correct, the player places a black or red checker on the board with the goal of connecting four in a row ( horizontally, vertically, or diagonally) before the opponent does. Players choose from four levels of difficulty; they can adjust the timing feature and whether to involve exponents and/or parentheses.

2011-01-01

290

First order vortex dynamics  

SciTech Connect

A non-dissipative model for vortex motion in thin superconductors is considered. The Lagrangian is a Galilean invariant version of the Ginzburg{endash}Landau model for time-dependent fields, with kinetic terms linear in the first time derivatives of the fields. It is shown how, for certain values of the coupling constants, the field dynamics can be reduced to first order differential equations for the vortex positions. Two vortices circle around one another at constant speed and separation in this model. {copyright} 1997 Academic Press, Inc.

Manton, N.S. [Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Silver Street, Cambridge CB3 9EW (England)

1997-05-01

291

High Order Multiplicity Moments  

SciTech Connect

We analyze the ratios of cumulants to factorial moments both for data and for the Monte Carlo generated events. For the PYTHIA generated events the moments are investigated both for the full and restricted range of phase-space and for the jets reconstructed from single particle momenta. The results cast doubts on the validity of extended local parton-hadron duality and suggest the possibility of more effective experimental investigations concerning the origin of the observed structure in the dependence of moments on their order.

Fialkowski, K.; Wit, R. [M. Smoluchowski Institute of Physics, Jagellonian University, 30-059 Cracow, ul.Reymonta 4 (Poland)

2006-04-11

292

Between order and chaos  

NASA Astrophysics Data System (ADS)

What is a pattern? How do we come to recognize patterns never seen before? Quantifying the notion of pattern and formalizing the process of pattern discovery go right to the heart of physical science. Over the past few decades physics' view of nature's lack of structure--its unpredictability--underwent a major renovation with the discovery of deterministic chaos, overthrowing two centuries of Laplace's strict determinism in classical physics. Behind the veil of apparent randomness, though, many processes are highly ordered, following simple rules. Tools adapted from the theories of information and computation have brought physical science to the brink of automatically discovering hidden patterns and quantifying their structural complexity.

Crutchfield, James P.

2012-01-01

293

Ordered photonic microstructures  

NASA Astrophysics Data System (ADS)

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.)

Chen, Kevin Ming

2001-09-01

294

Order in amorphous solids  

NASA Astrophysics Data System (ADS)

A solid is a system which has density modulations that are not erased by thermal motion, even on long timescales. The typical example is a crystal. Particles with soft, inter-penetrable cores may form such a solid. The remarkable fact that one can build a hard building with soft bricks can only be explained by the cooperation between an infinite number of particles. If soft particles may form a true, glassy solid phase, then we are forced to accept that an infinite coherence length must also exist for them. And yet, when we look at glass configurations, they appear definitely disordered, liquid-like. This is the mystery of glasses, which motivates the quest for a hidden order. I shall describe a coherence length that is accessible experimentally, and should diverge in an ideal glass state.

Kurchan, Jorge

2011-03-01

295

Order without design  

PubMed Central

Experimental reality in molecular and cell biology, as revealed by advanced research technologies and methods, is manifestly inconsistent with the design perspective on the cell, thus creating an apparent paradox: where do order and reproducibility in living systems come from if not from design? I suggest that the very idea of biological design (whether evolutionary or intelligent) is a misconception rooted in the time-honored and thus understandably precious error of interpreting living systems/organizations in terms of classical mechanics and equilibrium thermodynamics. This error, introduced by the founders and perpetuated due to institutionalization of science, is responsible for the majority of inconsistencies, contradictions, and absurdities plaguing modern sciences, including one of the most startling paradoxes - although almost everyone agrees that any living organization is an open nonequilibrium system of continuous energy/matter flow, almost everyone interprets and models living systems/organizations in terms of classical mechanics, equilibrium thermodynamics, and engineering, i.e., in terms and concepts that are fundamentally incompatible with the physics of life. The reinterpretation of biomolecules, cells, organisms, ecosystems, and societies in terms of open nonequilibrium organizations of energy/matter flow suggests that, in the domain of life, order and reproducibility do not come from design. Instead, they are natural and inevitable outcomes of self-organizing activities of evolutionary successful, and thus persistent, organizations co-evolving on multiple spatiotemporal scales as biomolecules, cells, organisms, ecosystems, and societies. The process of self-organization on all scales is driven by economic competition, obeys empirical laws of nonequilibrium thermodynamics, and is facilitated and, thus, accelerated by memories of living experience persisting in the form of evolutionary successful living organizations and their constituents.

2010-01-01

296

Order without design.  

PubMed

Experimental reality in molecular and cell biology, as revealed by advanced research technologies and methods, is manifestly inconsistent with the design perspective on the cell, thus creating an apparent paradox: where do order and reproducibility in living systems come from if not from design? I suggest that the very idea of biological design (whether evolutionary or intelligent) is a misconception rooted in the time-honored and thus understandably precious error of interpreting living systems/organizations in terms of classical mechanics and equilibrium thermodynamics. This error, introduced by the founders and perpetuated due to institutionalization of science, is responsible for the majority of inconsistencies, contradictions, and absurdities plaguing modern sciences, including one of the most startling paradoxes - although almost everyone agrees that any living organization is an open nonequilibrium system of continuous energy/matter flow, almost everyone interprets and models living systems/organizations in terms of classical mechanics, equilibrium thermodynamics, and engineering, i.e., in terms and concepts that are fundamentally incompatible with the physics of life. The reinterpretation of biomolecules, cells, organisms, ecosystems, and societies in terms of open nonequilibrium organizations of energy/matter flow suggests that, in the domain of life, order and reproducibility do not come from design. Instead, they are natural and inevitable outcomes of self-organizing activities of evolutionary successful, and thus persistent, organizations co-evolving on multiple spatiotemporal scales as biomolecules, cells, organisms, ecosystems, and societies. The process of self-organization on all scales is driven by economic competition, obeys empirical laws of nonequilibrium thermodynamics, and is facilitated and, thus, accelerated by memories of living experience persisting in the form of evolutionary successful living organizations and their constituents. PMID:20398287

Kurakin, Alexei

2010-04-14

297

Symmetry, shape, and order  

PubMed Central

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.

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

2007-01-01

298

Collaborative order management: toward standard solutions for interorganisational order management  

Microsoft Academic Search

Order management ranks among the key operational processes, and inefficiencies within this process have direct impacts on customer service, order cycle times as well as order execution costs. The massive investments in implementing systems for enterprise resource planning (ERP) have already led to significant improvements in managing orders across organisational units within enterprises. However, ERP systems have not been designed

Rainer Alt; Dimitrios Gizanis; Christine Legner

2005-01-01

299

A deuterium N.M.R. study of chain ordering in the liquid crystals 4,4'-di-n-heptyloxyazoxybenzene and 4-n-octyl-4'-cyanobiphenyl  

NASA Astrophysics Data System (ADS)

Deuterium N.M.R. spectra are described and analysed for two liquid crystals containing eight-membered alkyl or alkyloxy end chains, which are partially or fully deuteriated. The spectra yield quadrupolar and dipolar couplings which are assigned unambiguously to segment positions and which are then used to test certain theories of orientational ordering. We examine, in particular, the idea that a single ordering matrix S can describe the orientational order for non-rigid mesogens. It is shown that plots of ratios of quadrupole splittings, ?vi/?vj against ?vk/?vj, where i, j, k are different segment numbers are linear when j refers to the terminal methyl groups, but markedly non-linear otherwise. This constrasts with previous work on 4,4'-di-n-heptyloxyazoxybenzene by Bos et al. (1977, Molec. Crystals liq. Crystals, 40, 59) and hence is in disagreement with their view that such ratio plots can be used to obtain the biaxiallity in S. Calculations of segmental order parameters have been carried out which assume a single ordering matrix and which evaluate averages over internal conformations by invoking the rotameric state model to describe segmental energetics in the alkyl chains. The calculated order parameters are in agreement with the general features observed experimentally, but fail to give exact agreement with the variation of ordering along the chains. It is proposed that this failure is a consequence of assuming that a single S matrix can be used and that the N.M.R. data reveal the need to describe each conformation adopted by a molecule with a separate ordering matrix.

Boden, N.; Clark, L. D.; Bushby, R. J.; Emsley, J. W.; Luckhurst, G. R.; Stockley, C. P.

300

Ordering Genetic Algorithms and Deception  

Microsoft Academic Search

This paper considers deception in the context of ordering genetic algorithms (GAs). Order-four deceptive ordering problems are designed for absolute and relative ordering decoding. Three different crossover operators are used in both absolute and relative or- dering problems, and for each combination of crossover operator and coding, the schema survival probability is calculated. Simulation results show that no single crossover

Hillol Kargupta; Kalyanmoy Deb; David E. Goldberg

1992-01-01

301

Topology in Ordered Phases  

NASA Astrophysics Data System (ADS)

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

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

2006-08-01

302

Solving third order boundary value problem with fifth order method  

NASA Astrophysics Data System (ADS)

A fifth order direct method is developed for the numerical solution of nonlinear boundary value problems (BVPs) directly. Most of the existence research involving BVPs will reduce the problem to a system of first order Ordinary Differential Equations (ODEs). However, the proposed method will solve the third order BVPs directly without reducing to first order ODEs. The direct method will solve the nonlinear third order BVPs by shooting technique using constant step size. Numerical result is presented to illustrate the performance of the proposed method. The results clearly show that the proposed method is suitable for solving third order nonlinear BVPs.

Abdullah, Ahmad Shah; Abdul Majid, Zanariah; Senu, Norazak

2013-04-01

303

High order diamond differencing schemes  

Microsoft Academic Search

We present a generalization if the diamond differencing scheme to high-order spatial orders in one- and two-dimensional Cartesian geometries. Unlike existing variable-order nodal schemes our approach reduces to the conventional low-order diamond differencing scheme in the linear case and feature super convergence characteristics at all orders. This approach is demonstrated on one- and two-dimensional benchmark problems and is compared to

Alain Hébert

2006-01-01

304

Protective orders: questions and conundrums.  

PubMed

Current media portrayal of protective orders is often negative, focusing on weaknesses in how protective orders are obtained and enforced. This review of research findings on protective orders examines issues and suggests areas in need of future research to clarify and improve public policy. More specifically, this review has five main objectives: (a) to provide background information about partner violence and the need for protective orders; (b) to describe what protective orders are, how many women obtain them, and the advantages and disadvantages of obtaining protective orders; (c) to examine characteristics of women who seek protective orders; (d) to explore research on whether protective orders actually increase women's safety; and (e) to highlight opportunities and gaps in the practice and research literature regarding the use of protective orders for women with violent partners or ex-partners. PMID:16785286

Logan, T K; Shannon, Lisa; Walker, Robert; Faragher, Teri Marie

2006-07-01

305

Orientational order in liquid crystals by combining H2 and C13 nuclear magnetic resonance spectroscopy and density functional theory calculations  

NASA Astrophysics Data System (ADS)

Structural and orientational order properties of the liquid crystal 4,4' -bis-heptyl-azoxybenzene (HAB) have been obtained in its nematic and smectic- A phases by simultaneously analyzing several observables extracted from H2 and C13 nuclear magnetic resonance (NMR) spectra, i.e., H2 quadrupolar, H2-H1 and C13-H2 dipolar couplings, as well as C13 chemical shift anisotropy. C13 experiments required the application of high-resolution solid-state NMR techniques like H1 high-power decoupling and cross polarization, as well as the independent determination of chemical shift tensors by means of density functional theory (DFT) calculations, here performed taking into account the effect of the anisotropic medium by the polarizable continuum model method. The approach, consisting in the simultaneous analysis of all the H2 and C13 experimental data to derive orientational order parameters, and in the use of geometrical parameters determined by DFT methods, allows more detailed and reliable results to be obtained with respect to the traditional approach based on the sole analysis of H2 experiments.

Calucci, Lucia; Geppi, Marco; Marini, Alberto; Veracini, Carlo Alberto

2010-10-01

306

Signatures of hidden-order symmetry in torque oscillations, elastic constant anomalies, and field-induced moments in URu2Si2  

NASA Astrophysics Data System (ADS)

We discuss the conclusions on the symmetry of hidden order (HO) in URu2Si2 that may be drawn from recent torque experiments in a rotating magnetic field by Okazaki [Science0036-807510.1126/science.1197358 331, 439 (2011)] (to be published). They are very sensitive to changes in the magnetic susceptibility induced by HO. We show that the observed twofold angular torque oscillations give evidence that HO has degenerate E-type (yz, zx) symmetry where both components are realized. The oscillations have the wrong characteristics or are absent for the one-dimensional (1D) nontrivial representations like quadrupolar B1(x2-y2) and B2(xy) type HO or hexadecapolar A2[xy(x2-y2)] type HO. Therefore, they may be excluded as candidates for HO. We also predict the field-angular variation of possible field-induced Bragg peaks based on the underlying E-type order parameter and discuss the expected elastic constant anomalies.

Thalmeier, Peter; Takimoto, Tetsuya

2011-04-01

307

Deuterium Spin Probes of Backbone Order in Proteins: A 2H NMR Relaxation Study of Deuterated Carbon ? Sites  

PubMed Central

2H spin relaxation NMR experiments to study the dynamics of deuterated backbone ?-positions, D?, are developed. To date, solution-state 2H relaxation measurements in proteins have been confined to side-chain deuterons - primarily 13CH2D or 13CHD2 methyl groups. It is shown that quantification of 2H relaxation rates at D? backbone positions and the derivation of associated order parameters of C?-D? bond vector motions in small [U-15N,13C,2H]-labeled proteins is feasible with reasonable accuracy. The utility of the developed methodology is demonstrated on a pair of proteins - ubiquitin (8.5 kDa) at 10°C, 27°C, and 40°C, and a variant of GB1 (6.5 kDa) at 22°C. In both proteins, the D?-derived parameters of the global rotational diffusion tensor are in good agreement with those obtained from 15N relaxation rates. Semi-quantitative solution state NMR measurements yield an average value of the quadrupolar coupling constant, QCC, for D? sites in proteins equal to 174 kHz. Using the uniform value of QCC for all D? sites, we show that C?-D? bond vectors are motionally distinct from the backbone amide N-H bond vectors, with 2H-derived squared order parameters of C?-D? bond vector motions, S2 C?D?, on average slightly higher than their N-H amides counterparts, S2 NH. For ubiquitin, the 2H-derived backbone mobility compares well with that found in a 1-?s molecular dynamics simulation.

Sheppard, Devon; Li, Da-Wei; Bruschweiler, Rafael; Tugarinov, Vitali

2009-01-01

308

Higher-order uncertainty relations  

NASA Astrophysics Data System (ADS)

Using the non-negativity of Gram determinants of arbitrary order, we derive higher-order uncertainty relations for the symmetric uncertainty matrices of corresponding order n?>?2 to n Hermitean operators (n?=?2 is the usual case). The special cases of third-order and fourth-order uncertainty relations are considered in detail. The obtained third-order uncertainty relations are applied to the Lie groups SU(1,1) with three Hermitean basis operators (K1,K2,K0) and SU(2) with three Hermitean basis operators (J1,J2,J3) where, in particular, the group-coherent states of Perelomov type and of Barut Girardello type for SU(1,1) and the spin or atomic coherent states for SU(2) are investigated. The uncertainty relations for the determinant of the third-order uncertainty matrix are satisfied with the equality sign for coherent states and this determinant becomes vanishing for the Perelomov type of coherent states for SU(1,1) and SU(2). As an example of the application of fourth-order uncertainty relations, we consider the canonical operators (Q1,P1,Q2,P2) of two boson modes and the corresponding uncertainty matrix formed by the operators of the corresponding mean deviations, taking into account the correlations between the two modes. In two mathematical appendices, we prove the non-negativity of the determinant of correlation matrices of arbitrary order and clarify the principal structure of higher-order uncertainty relations.

Wünsche, A.

2006-07-01

309

Ordered community structure in networks  

NASA Astrophysics Data System (ADS)

Community structure in networks is often a consequence of homophily, or assortative mixing, based on some attribute of the vertices. For example, researchers may be grouped into communities corresponding to their research topic. This is possible if vertex attributes have unordered discrete values, but many networks exhibit assortative mixing by some ordered (discrete or continuous) attribute, such as age or geographical location. In such cases, the identification of discrete communities may be difficult or impossible. We consider how the notion of community structure can be generalized to networks that have assortative mixing by ordered attributes. We propose a method of generating synthetic networks with ordered communities and investigate the effect of ordered community structure on the spread of infectious diseases. We also show that current community detection algorithms fail to recover community structure in ordered networks, and evaluate an alternative method using a layout algorithm to recover the ordering.

Gregory, Steve

2012-04-01

310

Surface melting of electronic order.  

SciTech Connect

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.

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

311

The economics of ordering inventory.  

PubMed

Supplies constitute a major overhead expense in every dental practice. The real cost of supplies includes the ordering cost, the carrying cost and the acquisition cost. At the ideal ordering volume, the impact of these three factors is minimized and the lowest true cost in realized. This article describes two formulas that will help dental practices in determining their correct ordering volume and making accurate purchase decisions. Practices can achieve significant cost reductions by using these two simple techniques. PMID:9297953

Patterson, C

1997-09-01

312

Effect of pressure on the field-induced ordered phase in the heavy-fermion compound YbCo2Zn20  

NASA Astrophysics Data System (ADS)

The effect of pressure on the field-induced ordered phase for H ? <111> in the heavy-fermion compound YbCo2Zn20, which is presumably a field-induced antiferro-quadrupolar (FI-AFQ) phase, was investigated in the pressure range up to 4.5 GPa and under magnetic fields up to 80 kOe. When pressure is applied, the metamagnetic-like transition at H m =6 kOe shifts to lower fields and disappears around the quantum critical pressure P c ˜1.8 GPa. A pressure-induced antiferromagnetic (PI-AFM) phase appears at pressures above about 2 GPa, and the critical field H c of the PI-AFM phase increases with increasing pressure. On the other hand, the transition field H Q of the FI-AFQ phase decreases gradually without showing any anomalous behavior around P c and becomes obscure around 4 GPa, where H c of the PI-AFM phase and H Q of the FI-AFQ phase become comparable. The magnetic field versus pressure, H- P, phase diagram for H ? <111> at 0.1 K was constructed in the pressure range up to 4.5 GPa.

Takeuchi, Tetsuya; Taga, Yuki; Yoshiuchi, Shingo; Ohya, Masahiro; Hirose, Yusuke; Honda, Fuminori; Settai, Rikio; ?nuki, Yoshichika

2013-06-01

313

Order-disorder phase transition in CePt4In: Evidence fromIn115 and195 Pt NMR studies  

NASA Astrophysics Data System (ADS)

We present the results of nuclear magnetic resonance (NMR) studies on CePt4In crystallizing at ambient temperature in an ordered cubic MgCu4Sn-type structure (space group F-43m, no. 216). The In115 and Pt195 NMR powder spectra have provided microscopic evidence for the occurrence of the phase transition suggested by the specific heat anomaly at T0=205 K. Single-site (multiple-site) Pt195 (I=1/2) NMR spectra are observed above (below) T0, while the single-site In115 (I = 9/2) NMR signal disappears below T0. The Solomon echoes of half-integer quadrupolar nuclei with spin I = 9/2 have been observed. The Knight shifts 115Kiso(T) and 195K?(T) (? = //, ?, iso, ax) scale linearly with magnetic susceptibility ?(T). Pt195 NMR exhibits strong anisotropy of the Knight shift and nuclear spin-lattice relaxation rate due to the huge anisotropy of hyperfine fields (H///H?) ? 43. The (1/T1)iso are fast and temperature independent for both In115 and Pt195 nuclei, indicating that the spin fluctuation of the 4f electrons has a local nature at the Ce sites.

Nowak, Bogdan

2011-04-01

314

Virtual Tembaga Ordering System (VTOS)  

Microsoft Academic Search

This paper presents the development of Virtual Tembaga Ordering System (VTOS) that focused on interactivity in 3D product using Virtual Reality Modeling Language (VRML). VTOS was developed using PHP language with the integration of VRML capabilities in order to adapt real shopping experience for users while examining the product before purchase. Users\\/customers have the chance to view the 3D object

H. M. Omar; N. A. A. A. Bakar; N. M. Nor

2010-01-01

315

Latin Squares of Order 10  

Microsoft Academic Search

Abstract. We describe two independent computations of the number,of Latin squares of order 10. We also give counts of Latin rectangles with up to 10 columns, and estimates of the number of Latin squares of orders up to 15. Mathematics Reviews Subject Classiflcations: 05B15, 05-04

Brendan D. Mckay; Eric Rogoyski

1995-01-01

316

SOS for Higher Order Processes  

Microsoft Academic Search

Abstract We lay the foundations for a Structural Operational Seman - tics (SOS) framework for higher order processes Then, we propose a number of extensions to Bernstein's promoted tyft\\/tyxt format which aims at proving congruence of strong bisimilarity for higher order pro - cesses The extended format is called promoted PANTH This format is easier to apply and strictly more

Mohammad Reza Mousavi; Murdoch J. Gabbay; Michel A. Reniers

2005-01-01

317

Tensions between Liberty and Order.  

ERIC Educational Resources Information Center

|Explores the issue of balancing liberty and order within the United States. Discusses the role of the Bill of Rights, focusing on the amendments in the document and the later amendments that ensure the liberty of U.S. citizens. Explains how order and liberty are ensured and includes discussion questions. (CMK)|

Chemerinsky, Erwin

2002-01-01

318

WOMEN'S EXPERIENCES OF PROTECTION ORDERS  

Microsoft Academic Search

Forty three case studies form the major part of the evidence presented in the research. A range of women were involved, including those who had not applied for protection orders, those who had unsuccessful applications, and those who obtained protection orders. The case studies clearly point to ethnicity as an important factor in these women's experiences of seeking legal protection.

Ruth Busch; Neville Robertson

319

Introduction to Order of Operations  

NSDL National Science Digital Library

This video demonstration introduces order of operations for pre-algebra level learners. The presenter explains the correct order of operations (parentheses, exponents, multiplication/division, addition/subtraction) using a simple math problem as an introductory example. Flash is required to view the video. Running time for the video is 9:39.

2010-01-01

320

Localization-protected quantum order  

NASA Astrophysics Data System (ADS)

Closed quantum systems with quenched randomness exhibit many-body localized regimes wherein they do not equilibrate, even though prepared with macroscopic amounts of energy above their ground states. We show that such localized systems can order, in that individual many-body eigenstates can break symmetries or display topological order in the infinite-volume limit. Indeed, isolated localized quantum systems can order even at energy densities where the corresponding thermally equilibrated system is disordered, i.e., localization protects order. In addition, localized systems can move between ordered and disordered localized phases via nonthermodynamic transitions in the properties of the many-body eigenstates. We give evidence that such transitions may proceed via localized critical points. We note that localization provides protection against decoherence that may allow experimental manipulation of macroscopic quantum states. We also identify a “spectral transition” involving a sharp change in the spectral statistics of the many-body Hamiltonian.

Huse, David A.; Nandkishore, Rahul; Oganesyan, Vadim; Pal, Arijeet; Sondhi, S. L.

2013-07-01

321

7 CFR 1206.13 - Order.  

Code of Federal Regulations, 2013 CFR

...SERVICE (MARKETING AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE MANGO PROMOTION, RESEARCH, AND INFORMATION Mango Promotion, Research, and Information Order Definitions § 1206.13 Order. Order...

2013-01-01

322

7 CFR 1206.13 - Order.  

Code of Federal Regulations, 2012 CFR

...SERVICE (MARKETING AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE MANGO PROMOTION, RESEARCH, AND INFORMATION Mango Promotion, Research, and Information Order Definitions § 1206.13 Order. Order...

2012-01-01

323

7 CFR 1216.16 - Order.  

Code of Federal Regulations, 2012 CFR

...SERVICE (MARKETING AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE PEANUT PROMOTION, RESEARCH, AND INFORMATION ORDER Peanut Promotion, Research, and Information Order Definitions § 1216.16 Order....

2012-01-01

324

7 CFR 1214.12 - Order.  

Code of Federal Regulations, 2013 CFR

...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....

2013-01-01

325

7 CFR 1218.12 - Order.  

Code of Federal Regulations, 2012 CFR

...MARKETING AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE BLUEBERRY PROMOTION, RESEARCH, AND INFORMATION ORDER Blueberry Promotion, Research, and Information Order Definitions § 1218.12 Order....

2012-01-01

326

7 CFR 1218.12 - Order.  

Code of Federal Regulations, 2013 CFR

...MARKETING AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE BLUEBERRY PROMOTION, RESEARCH, AND INFORMATION ORDER Blueberry Promotion, Research, and Information Order Definitions § 1218.12 Order....

2013-01-01

327

Complex higher order derivative theories  

SciTech Connect

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.

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

328

Cosserat Operators of Higher Order  

NASA Astrophysics Data System (ADS)

A higher order version of Cosserat Operators is introduced. With a compactness result (the proof of which we can only sketch here, for details see Riedl in Cosserat operators of higher order and applications, PhD thesis, University of Bayreuth, 2010) based on a regularization property of these operators we gain insight to invertibility of the operator div : {H^{m,q}_0 (G) ? H^{m-1,q}_{0,0} (G)}, where {m in {N}, 1 < q < ?} and {G subset {R}^n} is a bounded domain with sufficiently smooth boundary. As an application, we get a very simple and effective method of treating higher order generalizations of Stokes' system.

Riedl, Thorsten

2013-04-01

329

Probing atomic ordering and multiple twinning in metal nanocrystals through their vibrations  

PubMed Central

Control of nanocrystal (NC) crystallinity currently raises great interest because of its potential benefits in both physics modeling and technological applications. Advances in methods for synthesizing perfect single-crystalline NCs are recent, so that the effect of crystallinity on NC properties has received only limited study and still needs to be properly investigated. Here, we report that crystallinity of gold NCs dramatically modifies their vibrations. Using low-frequency Raman scattering, we clearly demonstrate that single-domain NCs vibrate differently than their multiply twinned counterparts, through the splitting of the quadrupolar vibrations, which is only observed for the former. Using the resonant ultrasound approach, we calculate the vibrational frequencies of a gold sphere and show that elastic anisotropy induces a lift of degeneracy of the quadrupolar mode in good agreement with our experimental measurements. These findings open up challenging perspectives on using Raman spectroscopy to characterize nanocrystallinity.

Portales, H.; Goubet, N.; Saviot, L.; Adichtchev, S.; Murray, D. B.; Mermet, A.; Duval, E.; Pileni, M.-P.

2008-01-01

330

Probing atomic ordering and multiple twinning in metal nanocrystals through their vibrations.  

PubMed

Control of nanocrystal (NC) crystallinity currently raises great interest because of its potential benefits in both physics modeling and technological applications. Advances in methods for synthesizing perfect single-crystalline NCs are recent, so that the effect of crystallinity on NC properties has received only limited study and still needs to be properly investigated. Here, we report that crystallinity of gold NCs dramatically modifies their vibrations. Using low-frequency Raman scattering, we clearly demonstrate that single-domain NCs vibrate differently than their multiply twinned counterparts, through the splitting of the quadrupolar vibrations, which is only observed for the former. Using the resonant ultrasound approach, we calculate the vibrational frequencies of a gold sphere and show that elastic anisotropy induces a lift of degeneracy of the quadrupolar mode in good agreement with our experimental measurements. These findings open up challenging perspectives on using Raman spectroscopy to characterize nanocrystallinity. PMID:18818308

Portales, H; Goubet, N; Saviot, L; Adichtchev, S; Murray, D B; Mermet, A; Duval, E; Pileni, M-P

2008-09-25

331

Exploring Krypto (Order of Operations)  

NSDL National Science Digital Library

The rules of Krypto â combine five numbers using the standard arithmetic operations to create a target number. The game helps to develop number sense, computational skills, and an understanding of the order of operations.

Mathematics, Illuminations N.

2009-07-21

332

Zero Order Diffraction Display Systems.  

National Technical Information Service (NTIS)

This program examined the relative attributes of ZOD (Zero Order Diffraction) microimages FIH (Focused Image Holograms), and Standard Ektachrome (EK) material for application to high brightness displays. Specific comparison of brightness, resolution, cont...

B. R. Clay B. E. Hendrickson

1978-01-01

333

The keystone of world order  

Microsoft Academic Search

Traditional U.S. allies, including Singapore, have long perceived the United States as the region's great stabilizer and honest broker. As the keystone of regional and world order, however, Washington must have an appreciation for moderation and restraint.

Chong Guan Kwa; See Seng Tan

2001-01-01

334

John F. Kennedy Executive Orders  

NSDL National Science Digital Library

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.

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

1997-01-01

335

Higher-order Fibonacci numbers  

Microsoft Academic Search

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

Milan Randi?; Daniel A. Morales; Oswaldo Araujo

1996-01-01

336

Supersymmetric fifth order evolution equations  

SciTech Connect

This paper considers supersymmetric fifth order evolution equations. Within the framework of symmetry approach, we give a list containing six equations, which are (potentially) integrable systems. Among these equations, the most interesting ones include a supersymmetric Sawada-Kotera equation and a novel supersymmetric fifth order KdV equation. For the latter, we supply some properties such as a Hamiltonian structures and a possible recursion operator.

Tian, K. [LSEC, ICMSEC, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing 100190 (China) and Graduate School of Chinese Academy of Sciences, Beijing (China); Liu, Q. P. [Department of Mathematics, China University of Mining and Technology, Beijing 100083 (China)

2010-03-08

337

Modeling molecular order and dynamics of a liquid crystal by deuteron NMR  

Microsoft Academic Search

The quadrupolar splittings in deuterated 4-n-hexyloxy-4'-cyanobiphenyl (6OCB) have recently been reassigned with some certainty. This has necessitated a re-evaluation of the fitting of these splittings with the molecular mean field theory. The corresponding spectral densities of motion in this compound could not be successfully modeled before, partly because of the incorrect peak assignments to carbon positions 3 and 4 in

Ronald Y. Dong; X. Shen; G. M. Richards

1995-01-01

338

Order Parameters in Liquid Crystals.  

NASA Astrophysics Data System (ADS)

Available from UMI in association with The British Library. The extent to which an anisotropic dye dissolved in a liquid crystal host is ordered by the host and the effect of the dye upon the host, the Guest-Host interaction, is a matter of current interest. The Guest-Host interaction between two groups, one simple and one complex, of anthraquinone dyes with hydrogen- and non-hydrogen-bonding substituents dissolved in cyanobiphenyl or phenylcyclohexane/bicyclohexane hosts has been investigated by refractive index and absorption polarization techniques. A fluorescent dye in the same hosts has also been studied using these techniques and also using the method of fluorescence polarization. Results from refractive index measurements show that the inclusion of small amounts of dye in the liquid crystal host can significantly change the refractive indices and birefringence of the host material. It is found that some dyes in the cyanobiphenyl hosts changed the ordinary refractive index of the host such that the dyed host refractive index curves crossed the pure host curve and the mixtures which exhibited this crossing behaviour always have a higher order parameter than that of the pure host. This crossing behaviour is exhibited by both hydrogen-bonding and non -hydrogen-bonding dyes, but only occurs in the cyanobiphenyl hosts. Absorption polarization results reveal that dye order parameter is increased by increasing the length of the alkyl chain attached to the anthraquinone skeleton and also by the addition of thiophenyl groups to the anthraquinone molecule, whereas the methylation of amino groups attached to the anthraquinone skeleton significantly decreases the dye order parameter. Hydroxy groups attached to the dye molecule lower the dye order parameter in PCH/BCH hosts and also influence the shape of the order parameter curve. Results using a dye with two absorption maxima in the visible suggest that the molecular orientational distribution function of the dye is asymmetrical. It is noted that the dye order parameter is very sensitive to the chemical nature of the host. Order parameters determined from fluorescence polarization measurements are found to be lower than the corresponding values measured by absorption. The fourth rank order parameters measured by this method are found to be mainly negative and are thought to be due to neglecting the effect of rotational depolarization of the fluorescent dye molecules.

Davidson, Andre Noel

339

A Law of Order: Word Order Change in Classical Aztec  

ERIC Educational Resources Information Center

The verb in Classical Aztec is slowly moving from the end of the sentence to the beginning due to the attraction of sentence initial modal particles to the verb. Not only the function but also the position of elements should be examined to account for word-order change. (SCC)

Steele, Susan M.

1976-01-01

340

Ordered particles versus ordered pointers in the hybrid ordered plasma simulation (HOPS) code  

SciTech Connect

From a computational standpoint, particle simulation calculations for plasmas have not adapted well to the transitions from scalar to vector processing nor from serial to parallel environments. They have suffered from inordinate and excessive accessing of computer memory and have been hobbled by relatively inefficient gather-scatter constructs resulting from the use of indirect indexing. Lastly, the many-to-one mapping characteristic of the deposition phase has made it difficult to perform this in parallel. The authors` code sorts and reorders the particles in a spatial order. This allows them to greatly reduce the memory references, to run in directly indexed vector mode, and to employ domain decomposition to achieve parallelization. The field model solves pre-maxwell equations by interatively implicit methods. The OSOP (Ordered Storage Ordered Processing) version of HOPS keeps the particle tables ordered by rebuilding them after each particle pushing phase. Alternatively, the RSOP (Random Storage Ordered Processing) version keeps a table of pointers ordered by rebuilding them. Although OSOP is somewhat faster than RSOP in tests on vector-parallel machines, it is not clear this advantage will carry over to massively parallel computers.

Anderson, D.V.; Shumaker, D.E. [Lawrence Livermore National Laboratory, Berkeley, CA (United States)

1993-05-01

341

Judicial review of conservation orders  

SciTech Connect

Judicial review of orders issued by the Commissioner of Conservation may be sought under the authority of both Louisiana Revised Statutes 49:964 and Louisiana Revised Statutes 30:12. These statutes differ with respect to who may bring an action, the form of relief the reviewing court may grant, the scope of the evidence considered by the reviewing court, and the standards on the burden of proof. The application of laches under 30:12 is inconsistent with the 30-day delay periods provided by 49:964, and it is unworkable to the extent that it ignores the underlying need for finality of conservation orders. The continuing threat of subsequent court review destroys the credibility of the orders. Finality could be achieved under the current use of latches if a judicial determination established a definite length of reasonable delay. It is up to the legislature to correct the uncertainty introduced by 30:12. 91 references.

Brown, R.L. Jr.

1983-05-01

342

RISING CHINA AND WORLD ORDER  

Microsoft Academic Search

This book consists of the author's writings on China's perspective and policy with regard to its foreign relations and engagement of regional and global affairs. It covers issues ranging from the post-Cold War world order, China-US relations, the significance of China's rise, the North Korean nuclear crisis and China's policy, and China's relations with its neighbors in a new context.

Yunling Zhang

343

Temporal higher-order contracts  

Microsoft Academic Search

Behavioral contracts are embraced by software engineers because they document module interfaces, detect interface violations, and help identify faulty modules (packages, classes, functions, etc). This paper extends prior higher-order contract systems to also express and enforce temporal properties, which are common in software systems with imperative state, but which are mostly left implicit or are at best informally specified. The

Tim Disney; Cormac Flanagan; Jay McCarthy

2011-01-01

344

Automated First Order Natural Deduction  

Microsoft Academic Search

We present a proof-searching algorithm for the classical first order natural deduction calculus and prove its correctness. For any given task (if this task is indeed solvable), a searching algorithm terminates, either finding a corresponding natural deduction proof or giving a set of constraints, from which a counter-example can be extracted. Proofs of the properties which characterize correctness of the

Alexander Bolotov; Vyacheslav Bocharov; Alexander Gorchakov; Vasilyi Shangin

2005-01-01

345

The evolving global monetary order  

Microsoft Academic Search

In a speech at the Cato Institute, Jerry L. Jordan, President and CEO of the Federal Reserve Bank of Cleveland, discussed the forces shaping the emerging global monetary order and offered guidelines for the design of any international organization promoting efficient international financial markets. This Economic Commentary is adapted from his remarks at the Institute's Seventeenth Annual Monetary Conference on

Jerry L. Jordan

2000-01-01

346

Zero order diffraction display systems  

Microsoft Academic Search

This program examined the relative attributes of ZOD (Zero Order Diffraction) microimages FIH (Focused Image Holograms) holograms, and Standard Ektachrome (EK) material for application to high brightness displays. Specific comparison of brightness, resolution, contrast, and colorimetry were made using a breadboard viewing screen system allowing simultaneous side-by-side projection of the three media. Typical subject matter included aerial maps, resolution, and

B. R. Clay; B. E. Hendrickson

1978-01-01

347

Probabilistic First-Order Classification  

Microsoft Academic Search

We discuss the problem of classification using the first order hypotheses. This paper proposes an enhancement of classification based on the naive Bayesian scheme that is able to overcome the conditional independence assumption. Several experiments, involving some artificial and real-world, both propositional and relational domains, were conducted. The results indicate that the classification performance of propositional learners is reached when

Uros Pompe; Igor Kononenko

1997-01-01

348

Semirigid sets of diamond orders  

Microsoft Academic Search

An order relation ?ab on a set A is a diamond provided x ?aby holds exactly if x = a or y = b. A set R of diamonds on A is semirigid if the identity map on A and all constant self-maps of A are the only self-maps of A that are (jointly) isotone for all diamonds from R.

Vaktang Lashkia; Masahiro Miyakawa; Akihiro Nozaki; Grant Pogosyan; Ivo G. Rosenberg

1996-01-01

349

NCI Mouse Repository - Ordering Information  

Cancer.gov

Mouse models are provided free of charge through the NCI Mouse Repository, however, the customer is responsible for shipping charges if the shipment must go by air or special truck. There is no charge for normal truck delivery. Up to three (3) breeder pairs are routinely supplied on an order. On occasion, larger numbers of breeder pairs may be available - please inquire.

350

Order information in dichotic memory  

Microsoft Academic Search

Three experiments were performed using a recognition probe procedure to test the S's recognition of the order of 2 items from a dichotically presented list. In all 3 experiments, all of the 56 undergraduate Ss were unable to recognize simultaneous items as having been simultaneous unless the critical pair was the last pair in the list. In contrast, they were

Catherine G. Penney

1976-01-01

351

Japanese religion as ritual order  

Microsoft Academic Search

It is argued in this paper that beneath the superficial analysis of Japanese ‘religions’ such as Buddhism, Shinto, Confucianism and the New Religions, there is one dominant ideological complex which, following some Japanese scholars, can conveniently be dubbed ‘The Japanese Religion’ or Nihonkyo. This Japanese religion is a ritual order based on the hierarchical concept of ‘ie’ and its variations

Timothy Fitzgerald

1993-01-01

352

Weighted order statistic classifiers with large rank-order margin.  

SciTech Connect

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.

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

2003-01-01

353

7 CFR 1219.17 - Order.  

Code of Federal Regulations, 2012 CFR

...MARKETING AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE HASS AVOCADO PROMOTION, RESEARCH, AND INFORMATION Hass Avocado Promotion, Research, and Information Order Definitions § 1219.17 Order....

2012-01-01

354

7 CFR 1219.17 - Order.  

Code of Federal Regulations, 2013 CFR

...MARKETING AGREEMENTS AND ORDERS; MISCELLANEOUS COMMODITIES), DEPARTMENT OF AGRICULTURE HASS AVOCADO PROMOTION, RESEARCH, AND INFORMATION Hass Avocado Promotion, Research, and Information Order Definitions § 1219.17 Order....

2013-01-01

355

Recent advances in ordered intermetallics  

SciTech Connect

Ordered intermetallic alloys based on aluminides and silicides offer many advantages for structural use at high temperatures in hostile environments. Attractive properties include excellent oxidation and corrosion resistance, light weight, and superior strength at high temperatures. The major concern for structural use of intermetallics was their low ductility and poor fracture resistance at ambient temperatures. For the past 10 years, considerable effort was devoted to R&D of ordered intermetallic alloys, and progress has been made on understanding intrinsic and extrinsic factors controlling brittle fracture in intermetallic alloys based on aluminides and silicides. Parallel effort on alloy design has led to the development of a number of ductile and strong intermetallic alloys based on Ni{sub 3}Al, NiAl, Fe{sub 3}Al, FeAl, Ti{sub 3}Al, and TiAl systems for structural applications.

Liu, C.T.

1994-12-31

356

The ordered limit of superconductivity  

NASA Astrophysics Data System (ADS)

The conventional understanding of superconductivity rests heavily on the physics of Bose gases. In the high temperature superconductors, the superfluid is very strongly correlated being on the verge of solidifying into a stripe phase. Inspired by this problem, we employ quantum field theory techniques to construct the limit of “optimally ordered” superconductivity. These superconductors can be viewed as quantum elastic entities different from normal crystals in the sense that they lost their rigidity against shear stress as dual Bose condensates of quantum dislocations. Exciting new physical properties emerge which can, in principle, be measured although they invoke unconventional experiments: quantum liquid crystalline orders, oscillations of magnetic screening currents, and new collective modes found in the dynamical electromagnetic response.

Cvetkovic, V.; Zaanen, J.; Nussinov, Z.; Mukhin, S.

2005-12-01

357

International nuclear order: a rejoinder  

Microsoft Academic Search

The article‘Nuclear enlightenment and counter-enlightenment by William Walker opened the special issue of International Affairs which was published in May 2007. In it, he claimed that the United States departed in the late 1990s and early 2000s, at the height of its hegemonic influence, from a conception of international nuclear order that it had held to, with few interruptions, over

WILLIAM WALKER

2007-01-01

358

Ordering Juice Drinks (grade 4)  

NSDL National Science Digital Library

This is a sample PARCC assessment task based on CCSS grade 4 operations and algebraic thinking standards as well as the number and operations in base ten standards. In this interactive single task students must solve a multi-step problem by completing an order receipt for orange juice. Included are the alignments to the CCSS, a scoring rubric and background on the task itself.

2013-01-01

359

Highly ordered noncrystalline metallic phase.  

PubMed

We report the characterization of a unique metallic glass that, during rapid cooling of an Al-Fe-Si melt, forms by nucleation, followed by growth normal to a moving interface between the solid and melt with partitioning of the chemical elements. We determine experimentally that this is not a polycrystalline composite with nanometer-sized grains, and conclude that this may be a new kind of structure: an atomically ordered, isotropic, noncrystalline solid, possessing no long-range translational symmetry. PMID:23863012

Long, Gabrielle G; Chapman, Karena W; Chupas, Peter J; Bendersky, Leonid A; Levine, Lyle E; Mompiou, Frédéric; Stalick, Judith K; Cahn, John W

2013-07-02

360

Order-Preserving Symmetric Encryption  

Microsoft Academic Search

We initiate the cryptographic study of order-preserving symmetric encryption (OPE), a prim- itive suggested in the database community by Agrawal et al. (SIGMOD '04) for allowing ecient range queries on encrypted data. Interestingly, we rst show that a straightforward relaxation of standard security notions for encryption such as indistinguishability against chosen-plaintext attack (IND-CPA) is unachievable by a practical OPE scheme.

Alexandra Boldyreva; Nathan Chenette; Younho Lee; Adam O’Neill

2009-01-01

361

Dynamic Variable Ordering in CSPs  

Microsoft Academic Search

We investigate the dynamic variable ordering(DVO) technique com- monly used in conjunction with tree-search algorithms for s olving constraint sat- isfaction problems. We first provide an implementation meth odology for adding DVO to an arbitrary tree-search algorithm. Our methodology is applicable to a wide range of algorithms including those that maintain complicated information about the search history, like backmarking. We

Fahiem Bacchus; Paul Van Run

1995-01-01

362

Macroscopically ordered water in nanopores  

PubMed Central

Water confined into the interior channels of narrow carbon nanotubes or transmembrane proteins forms collectively oriented molecular wires held together by tight hydrogen bonds. Here, we explore the thermodynamic stability and dipolar orientation of such 1D water chains from nanoscopic to macroscopic dimensions. We show that a dipole lattice model accurately recovers key properties of 1D confined water when compared to atomically detailed simulations. In a major reduction in computational complexity, we represent the dipole model in terms of effective Coulombic charges, which allows us to study pores of macroscopic lengths in equilibrium with a water bath (or vapor). We find that at ambient conditions, the water chains filling the tube are essentially continuous up to macroscopic dimensions. At reduced water vapor pressure, we observe a 1D Ising-like filling/emptying transition without a true phase transition in the thermodynamic limit. In the filled state, the chains of water molecules in the tube remain dipole-ordered up to macroscopic lengths of ?0.1 mm, and the dipolar order is estimated to persist for times up to ?0.1 s. The observed dipolar order in continuous water chains is a precondition for the use of nanoconfined 1D water as mediator of fast long-range proton transport, e.g., in fuel cells. For water-filled nanotube bundles and membranes, we expect anti-ferroelectric behavior, resulting in a rich phase diagram similar to that of a 2D Coulomb gas.

Kofinger, Jurgen; Hummer, Gerhard; Dellago, Christoph

2008-01-01

363

The costs and determinants of order aggressiveness  

Microsoft Academic Search

This paper examines the costs and determinants of order aggressiveness. Aggressive orders have larger price impacts but smaller opportunity costs than passive orders. Price impacts are amplified by large orders, small firms, and volatile stock prices. To minimize the implementation shortfall, the optimal strategy is to enter buy (sell) orders at the bid (ask). Aggressive buy (sell) orders tend to

Mark D. Griffiths; Brian F. Smith; D. Alasdair S. Turnbull; Robert W. White

2000-01-01

364

Information properties of order statistics and spacings  

Microsoft Academic Search

We explore properties of the entropy, Kullback-Leibler information, and mutual information for order statistics. The probability integral transformation plays a pivotal role in developing our results. We provide bounds for the entropy of order statistics and some results that relate entropy ordering of order statistics to other well-known orderings of random variables. We show that the discrimination information between order

Nader Ebrahimi; Ehsan S. Soofi; Hassan Zahedi

2004-01-01

365

The Fitness of Genomic Order  

NASA Astrophysics Data System (ADS)

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.

Zhang, Qiucen; Vyawahare, Saurabh; Austin, Robert

2012-02-01

366

Kn 26, a new quadrupolar planetary nebula (Guerrero+, 2013)  

NASA Astrophysics Data System (ADS)

Narrow-band H?, [NII] ?6583, and [OIII] ?5007 images of Kn 26 were acquired on June 21, 2009 using ALFOSC (Andalucia Faint Object Spectrograph and Camera) at the 2.56m Nordic Optical Telescope (NOT) of the Observatorio de Roque de los Muchachos (ORM, La Palma, Spain). Narrow-band H2 2.1218um, Br? 2.1658um, and K continuum at 2.270um images of Kn 26 were obtained on June 27, 2010 using LIRIS at the Cassegrain focus of the 4.2m William Herschel Telescope (WHT) at the ORM. Intermediate-resolution long-slit spectra of Kn 26 were obtained on October 5, 2011 using the ALBIREO spectrograph at the 1.5m telescope of the Observatorio de Sierra Nevada (OSN), Granada, Spain. Long-slit high-dispersion spectroscopy on the H? and [NII] ?6583 lines of Kn 26 has been acquired on June 13, 2010 using the Manchester Echelle Spectrometer (MES) mounted on the 2.1m (f/7.5) telescope at the Observatorio Astronomico Nacional de San Pedro Martir (OAN-SPM, Mexico). (2 data files).

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

2013-03-01

367

Long-range electron binding to quadrupolar molecules.  

PubMed

An excess electron can be bound to a molecule in a very diffuse orbital as a result of the long-range contributions of the molecular electrostatic field. Following a systematic search, we report experimental evidence that quadrupole binding occurs for the trans-succinonitrile molecule (EA=20+/-2 meV), while the gauche-succinonitrile conformer supports a dipole-bound anion state (EA=108+/-10 meV). Theoretical calculations at the DFT/B3LYP level support these interpretations and give electron affinities of 20 and 138 meV, respectively. PMID:14995770

Desfrançois, C; Bouteiller, Y; Schermann, J P; Radisic, D; Stokes, S T; Bowen, K H; Hammer, N I; Compton, R N

2004-02-27

368

Long-Range Electron Binding to Quadrupolar Molecules  

NASA Astrophysics Data System (ADS)

An excess electron can be bound to a molecule in a very diffuse orbital as a result of the long-range contributions of the molecular electrostatic field. Following a systematic search, we report experimental evidence that quadrupole binding occurs for the trans-succinonitrile molecule (EA=20±2 meV), while the gauche-succinonitrile conformer supports a dipole-bound anion state (EA=108±10 meV). Theoretical calculations at the DFT/B3LYP level support these interpretations and give electron affinities of 20 and 138meV, respectively.

Desfrançois, C.; Bouteiller, Y.; Schermann, J. P.; Radisic, D.; Stokes, S. T.; Bowen, K. H.; Hammer, N. I.; Compton, R. N.

2004-02-01

369

Ordering Phenomena in Undercooled Alloys  

SciTech Connect

Much of the work performed under this grant was devoted to using modern ideas in kinetics to understand atom movements in metallic alloys far from thermodynamic equilibrium. Kinetics arguments were based explicitly on the vacancy mechanism for atom movements. The emphasis was on how individual atom movements are influenced by the local chemical environment of the moving atom, and how atom movements cause changes in the local chemical environments. The author formulated a kinetic master equation method to treat atom movements on a crystal lattice with a vacancy mechanism. Some of these analyses [3,10,16] are as detailed as any treatment of the statistical kinetics of atom movements in crystalline alloys. Three results came from this work. Chronologically they were (1) A recognition that tracking time dependencies is not necessarily the best way to study kinetic phenomena. If multiple order parameters can be measured in a material, the ''kinetic path'' through the space spanned by these order parameters maybe just as informative about the chemical factors that affect atom movements [2,3,5-7,9-11,14-16,18,19,21,23,24,26,36,37]. (2) Kinetic paths need not follow the steepest gradient of the free energy function (this should be well-known), and for alloys far from equilibrium the free energy function can be almost useless in describing kinetic behavior. This is why the third result surprised me. (3) In cluster approximations with multiple order parameters, saddle points are common features of free energy functions. Interestingly, kinetic processes stall or change time scale when the kinetic path approaches a state at a saddle point in the free energy function, even though these states exist far from thermodynamic equilibrium. The author calls such a state a ''pseudostable'' (falsely stable) state [6,21,26]. I have also studied these phenomena by more ''exact'' Monte Carlo simulations. The kinetic paths showed features similar to those found in analytical theories. The author found that a microstructure with interfaces arranged in space as a periodic minimal surface is a probably an alloy at a saddle point in its free energy function [21,26,37].

Fultz, Brent

1997-07-17

370

Recent advances in ordered intermetallics  

SciTech Connect

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.

Liu, C.T.

1992-12-31

371

Logistic equation of arbitrary order  

NASA Astrophysics Data System (ADS)

The paper is concerned with the new logistic equation of arbitrary order which describes the performance of complex executive systems X vs. number of tasks N, operating at limited resources K, at non-extensive, heterogeneous self-organization processes characterized by parameter f. In contrast to the classical logistic equation which exclusively relates to the special case of sub-extensive homogeneous self-organization processes at f=1, the proposed model concerns both homogeneous and heterogeneous processes in sub-extensive and super-extensive areas. The parameter of arbitrary order f, where -?

Grabowski, Franciszek

2010-08-01

372

Dislocation sources in ordered intermetallics  

SciTech Connect

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.

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

373

Entanglement negativity and topological order  

NASA Astrophysics Data System (ADS)

We use the entanglement negativity, a measure of entanglement for mixed states, to probe the structure of entanglement in the ground state of a topologically ordered system. Through analytical calculations of the negativity in the ground state(s) of the toric code model, we explicitly show that the pure-state entanglement of a region A and its complement B is the sum of two types of contributions: boundary entanglement and long-range entanglement. Boundary entanglement is seen to be insensitive to tracing out the degrees of freedom in the interior of regions A and B, and therefore it entangles only degrees of freedom in A and B that are close to their common boundary. We recover the well-known result that boundary entanglement is proportional to the size of each boundary separating A and B and it includes an additive, universal correction. The second, long-range, contribution to pure-state entanglement appears only when A and B are noncontractible regions (e.g., on a torus) and it is seen to be destroyed when tracing out a noncontractible region in the interior of A or B. In the toric code, only the long-range contribution to the entanglement depends on the specific ground state under consideration.

Lee, Yirun Arthur; Vidal, Guifre

2013-10-01

374

Fourth order spatial derivative gravity  

NASA Astrophysics Data System (ADS)

In this work, we study a modified theory of gravity that contains up to fourth order spatial derivatives as a model for the Ho?ava-Lifshitz gravity. The propagator is evaluated and, as a result, one extra pole is obtained, corresponding to a spin-2 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 been shown to have no dynamics, remaining only the 2 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 nonpole 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.

Bemfica, F. S.; Gomes, M.

2011-10-01

375

Repeated Red-Black ordering  

NASA Astrophysics Data System (ADS)

Hereafter, we describe and analyze, from both a theoretical and a numerical point of view, an iterative method for efficiently solving symmetric elliptic problems with possibly discontinuous coefficients. In the following, we use the Preconditioned Conjugate Gradient method to solve the symmetric positive definite linear systems which arise from the finite element discretization of the problems. We focus our interest on sparse and efficient preconditioners. In order to define the preconditioners, we perform two steps: first we reorder the unknowns and then we carry out a (modified) incomplete factorization of the original matrix. We study numerically and theoretically two preconditioners, the second preconditioner corresponding to the one investigated by Brand and Heinemann [2]. We prove convergence results about the Poisson equation with either Dirichlet or periodic boundary conditions. For a meshsizeh, Brand proved that the condition number of the preconditioned system is bounded byO(h-1/2) for Dirichlet boundary conditions. By slightly modifying the preconditioning process, we prove that the condition number is bounded byO(h-1/3).

Ciarlet, P.

1994-09-01

376

Ordering in classical Coulombic systems.  

SciTech Connect

The author discusses the properties of classical Coulombic matter at low temperatures. It has been well known for some time [1,2] that infinite Coulombic matter will crystallize in body-centered cubic form when the quantity {Lambda} (the dimensionless ratio of the average two-particle Coulomb energy to the kinetic energy per particle) is larger than {approximately}175. But the systems of such particles that have been produced in the laboratory in ion traps, or ion beams, are finite with surfaces defined by the boundary conditions that have to be satisfied. This results in ion clouds with sharply defined curved surfaces, and interior structures that show up as a set of concentric layers that are parallel to the outer surface. The ordering does not appear to be cubic, but the charges on each shell exhibit a ''hexatic'' pattern of equilateral triangles that is the characteristic of liquid crystals. The curvature of the surfaces prevents the structures on successive shells from interlocking in any simple fashion. This class of structures was first found in simulations [3] and later in experiments [4].

Schiffer, J. P.

1998-01-22

377

46 CFR Sec. 7 - Job order numbering.  

Code of Federal Regulations, 2010 CFR

...NATIONAL SHIPPING AUTHORITY MASTER LUMP SUM 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 thereto awarded to a...

2009-10-01

378

46 CFR Sec. 7 - Job order numbering.  

Code of Federal Regulations, 2010 CFR

...NATIONAL SHIPPING AUTHORITY MASTER LUMP SUM 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 thereto awarded to a...

2010-10-01

379

Magnetic Field Induced Phase Transitions in Gd(sub 5) (Si(sup 1.95)Ge(sup2.05)) Single Crystal and the Anisotropic Magnetocaloric Effect.  

National Technical Information Service (NTIS)

The magnetization measurements using a Gd5(Si1.95Ge2.0.) single crystal with the magnetic field applied along three crystalIographic directions, (OO1), (OlO) and (l00), were carried out as function of applied field (0 - 56 kOe) at various temperatures (Ar...

H. Tang V. K. Pecharsky A. O. Pecharsky

2005-01-01

380

Order Submission Strategy and the Curious Case of Marketable Limit Orders  

Microsoft Academic Search

We provide empirical evidence on order submission strategy of investors with similar com- mitments to trade by comparing the execution costs of market orders and marketable limit orders (i.e., limit orders with the same trading priority as market orders). The results in- dicate the unconditional trading costs of marketable limit orders are significantly greater than market orders. We attribute the

Mark Peterson; Erik Sirri

2002-01-01

381

Sodium interaction with ordered structures in mammalian red blood cells detected by Na-23 double quantum NMR.  

PubMed

Na-23 double and triple quantum filtered NMR spectra of intact dog and human red blood cells were measured with the pulse sequence 90 degrees-tau/2-180 degrees-tau/2-theta degrees-t1-theta degrees-t2(Acq). For theta = 90 degrees the triple quantum filtered spectra exhibited the typical multiple quantum filtered lineshape, characteristic of isotropic media, while the double quantum filtered ones presented a superposition of two signals, whose proportion depended on the creation time tau. This effect is due to the formation of both second and third rank tensors. The formation of the second rank tensor, T21 results from non-zero residual quadrupolar interaction and is related to the anisotropic motion of sodium ions. Measurements of the double quantum filtered spectra with theta = 54.7 degrees enabled the detection of the contribution of T21 exclusively. No residual quadrupolar interaction was detected for sodium in the cytoplasm, while unsealed ghosts displayed the double quantum filtered spectral pattern, similar to that of intact cells. The anisotropy of motion of the sodium at the plasma membrane of mammalian erythrocytes depended on the integrity of the cytoskeleton network. Theoretical analysis of the double quantum filtered spectra gave a value of residual quadrupolar splitting of approximately 20 Hz for intact unsealed ghosts. The data presented prove that double quantum filtering is a sensitive technique for detection of motional anisotropies in biological systems. PMID:8494983

Shinar, H; Knubovets, T; Eliav, U; Navon, G

1993-04-01

382

Sodium interaction with ordered structures in mammalian red blood cells detected by Na-23 double quantum NMR.  

PubMed Central

Na-23 double and triple quantum filtered NMR spectra of intact dog and human red blood cells were measured with the pulse sequence 90 degrees-tau/2-180 degrees-tau/2-theta degrees-t1-theta degrees-t2(Acq). For theta = 90 degrees the triple quantum filtered spectra exhibited the typical multiple quantum filtered lineshape, characteristic of isotropic media, while the double quantum filtered ones presented a superposition of two signals, whose proportion depended on the creation time tau. This effect is due to the formation of both second and third rank tensors. The formation of the second rank tensor, T21 results from non-zero residual quadrupolar interaction and is related to the anisotropic motion of sodium ions. Measurements of the double quantum filtered spectra with theta = 54.7 degrees enabled the detection of the contribution of T21 exclusively. No residual quadrupolar interaction was detected for sodium in the cytoplasm, while unsealed ghosts displayed the double quantum filtered spectral pattern, similar to that of intact cells. The anisotropy of motion of the sodium at the plasma membrane of mammalian erythrocytes depended on the integrity of the cytoskeleton network. Theoretical analysis of the double quantum filtered spectra gave a value of residual quadrupolar splitting of approximately 20 Hz for intact unsealed ghosts. The data presented prove that double quantum filtering is a sensitive technique for detection of motional anisotropies in biological systems. Images FIGURE 5

Shinar, H; Knubovets, T; Eliav, U; Navon, G

1993-01-01

383

High-temperature ordered intermetallic alloys II  

SciTech Connect

This book contains over 50 selections. Some of the titles are: Order-disorder behavior of grain boundaries in a two-dimensional model ordered alloy; Dislocation reactions at grain boundaries in Ll/sub 2/ ordered alloys; Creep cavitation in a nickel aluminide; Effects of elastic anisotropy on the anomalious yield behavior of cubic ordered alloys; and Processing technology for nickel aluminides.

Stoloff, N.S.; Koch, C.C.; Liu, C.T.; Izumi, O.

1987-01-01

384

46 CFR Sec. 7 - Job order numbering.  

Code of Federal Regulations, 2012 CFR

...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...

2012-10-01

385

46 CFR Sec. 7 - Job order numbering.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Job order numbering. Sec. 7 Section Sec...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...

2011-10-01

386

Optimal ordering policy in a distribution system  

Microsoft Academic Search

In conventional inventory management, the retailers monitor their own inventory levels and place orders at the distributor when they think it is the appropriate time to reorder. The distributor receives these orders from the retailers, prepares the product for delivery. Similarly, the distributor will place an order at the manufacturer at the appropriate time.Generally, the order that the distributor places

Jing-An Li; Yue Wu; Kin Keung Lai; Ke Liu

2006-01-01

387

Reply to ``Comment on `Transition from Bose glass to a condensate of triplons in Tl1-xKxCuCl3' ''  

NASA Astrophysics Data System (ADS)

Showing low-temperature specific heat and other experimental data and also on the basis of established physics, we argue against the comment made by Zheludev and Hüvonnen critiquing our recent study on the magnetic-field-induced spin ordering and critical behavior in Tl1-xKxCuCl3, which is described as the Bose glass-condensate transition of triplons.

Yamada, Fumiko; Tanaka, Hidekazu; Ono, Toshio; Nojiri, Hiroyuki

2011-06-01

388

Generalized structure of higher order nonclassicality  

NASA Astrophysics Data System (ADS)

A generalized notion of higher order nonclassicality (in terms of higher order moments) is introduced. Under this generalized framework of higher order nonclassicality, conditions of higher order squeezing and higher order subpoissonian photon statistics are derived. A simpler form of the Hong-Mandel higher order squeezing criterion is derived under this framework by using an operator ordering theorem introduced by us in [A. Pathak, J. Phys. A 33 (2000) 5607]. It is also generalized for multi-photon Bose operators of Brandt and Greenberg. Similarly, condition for higher order subpoissonian photon statistics is derived by normal ordering of higher powers of number operator. Further, with the help of simple density matrices, it is shown that the higher order antibunching (HOA) and higher order subpoissonian photon statistics (HOSPS) are not the manifestation of the same phenomenon and consequently it is incorrect to use the condition of HOA as a test of HOSPS. It is also shown that the HOA and HOSPS may exist even in absence of the corresponding lower order phenomenon. Binomial state, nonlinear first order excited squeezed state (NLESS) and nonlinear vacuum squeezed state (NLVSS) are used as examples of quantum state and it is shown that these states may show higher order nonclassical characteristics. It is observed that the Binomial state which is always antibunched, is not always higher order squeezed and NLVSS which shows higher order squeezing does not show HOSPS and HOA. The opposite is observed in NLESS and consequently it is established that the HOSPS and HOS are two independent signatures of higher order nonclassicality.

Verma, Amit; Pathak, Anirban

2010-02-01

389

49 CFR 1503.425 - Compromise orders.  

Code of Federal Regulations, 2012 CFR

...PROCEDURAL RULES INVESTIGATIVE AND ENFORCEMENT PROCEDURES Assessment of Civil Penalties by TSA § 1503.425 Compromise orders...Issuance. At any time before the issuance of an Order Assessing Civil Penalty under this subpart, an agency...

2012-10-01

390

49 CFR 1503.423 - Consent orders.  

Code of Federal Regulations, 2011 CFR

...PROCEDURAL RULES INVESTIGATIVE AND ENFORCEMENT PROCEDURES Assessment of Civil Penalties by TSA § 1503.423 Consent orders. (a) Issuance . At any time before the issuance of an Order Assessing Civil Penalty under this subpart, an agency...

2011-10-01

391

47 CFR 1.1415 - Other orders.  

Code of Federal Regulations, 2012 CFR

...1415 Section 1.1415 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL PRACTICE AND PROCEDURE Grants by Random Selection Pole Attachment Complaint Procedures § 1.1415 Other orders. The Commission may issue such other orders...

2012-10-01

392

48 CFR 916.505 - Ordering.  

Code of Federal Regulations, 2012 CFR

...Ordering. 916.505 Section 916.505 Federal Acquisition Regulations System DEPARTMENT OF ENERGY CONTRACTING METHODS AND CONTRACT TYPES TYPES OF CONTRACTS Indefinite-Delivery Contracts 916.505 Ordering....

2012-10-01

393

Logistic Order Statistics and Their Properties.  

National Technical Information Service (NTIS)

Order statistics from the logistic distribution have been studied and their moments and distributional properties have been discussed. Recurrence relations satisfied by the single and the product moments of order statistics are presented. Series expansion...

N. Balakrishnan S. S. Gupta

1990-01-01

394

40 CFR 90.503 - Test orders.  

Code of Federal Regulations, 2013 CFR

...families or deletes engine families from its production, that...SEA test order for which the family or configuration, as appropriate...met, the Administrator may issue additional test orders to test those families or configurations for...

2013-07-01

395

40 CFR 89.503 - Test orders.  

Code of Federal Regulations, 2013 CFR

...families or deletes engine families from its production, that...SEA test order for which the family fails under § 89.510 or...met, the Administrator may issue additional test orders to test those families for which evidence...

2013-07-01

396

High-order optics of multipole magnets.  

National Technical Information Service (NTIS)

We have developed a new capability to compute third and fifth order Lie algebraic transfer maps for a family of realistic multipole magnets, including dipoles. The general Hamiltonian is expanded symbolically to arbitrary order. The vector potential off a...

P. Walstrom F. Neri T. Mottershead

1990-01-01

397

Control of Initialized Fractional-Order Systems.  

National Technical Information Service (NTIS)

Due to the importance of historical effects in fractional-order systems, this paper presents a general fractional-order control theory that includes the time-varying initialization response. Previous studies have not properly accounted for these historica...

C. F. Lorenzo T. T. Hartley

2002-01-01

398

More Ado About Economic Order Quantities (Eoq).  

National Technical Information Service (NTIS)

The paper is concerned with the determination of explicit expressions for economic order quantities and reorder levels, such that the cost of ordering and holding inventory is minimized for specific backorder constraints. Holding costs are applied either ...

V. J. Presutti R. C. Trepp

1970-01-01

399

21 CFR 1312.47 - Final order.  

Code of Federal Regulations, 2013 CFR

...DEPARTMENT OF JUSTICE IMPORTATION AND EXPORTATION OF CONTROLLED SUBSTANCES Hearings § 1312.47 Final order. As...shall include the findings of fact and conclusions of law upon which the order is based. The...

2013-04-01

400

21 CFR 1308.45 - Final order.  

Code of Federal Regulations, 2013 CFR

...ADMINISTRATION, DEPARTMENT OF JUSTICE SCHEDULES OF CONTROLLED SUBSTANCES Hearings § 1308.45 Final order. As...final rule and the findings of fact and conclusions of law upon which the rule is based. This order...

2013-04-01

401

7 CFR 1212.15 - Order.  

Code of Federal Regulations, 2012 CFR

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

2012-01-01

402

7 CFR 1212.15 - Order.  

Code of Federal Regulations, 2013 CFR

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

2013-01-01

403

On the order of general linear methods.  

SciTech Connect

General linear (GL) methods are numerical algorithms used to solve ODEs. The standard order conditions analysis involves the GL matrix itself and a starting procedure; however, a finishing method (F) is required to extract the actual ODE solution. The standard order analysis and stability are sufficient for the convergence of any GL method. Nonetheless, using a simple GL scheme, we show that the order definition may be too restrictive. Specifically, the order for GL methods with low order intermediate components may be underestimated. In this note we explore the order conditions for GL schemes and propose a new definition for characterizing the order of GL methods, which is focused on the final result--the outcome of F--and can provide more effective algebraic order conditions.

Constantinescu, E. M.; Mathematics and Computer Science

2009-09-01

404

Contact Geometry of Second Order I  

Microsoft Academic Search

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,

Keizo Yamaguchi

405

14 CFR 16.243 - Consent orders.  

Code of Federal Regulations, 2010 CFR

... (c) If the issuance of a consent order has been agreed upon by all...parties to the hearing, the proposed consent order shall be filed with the hearing...with a draft order adopting the consent decree and dismissing the case, for...

2009-01-01

406

14 CFR 16.243 - Consent orders.  

Code of Federal Regulations, 2010 CFR

... (c) If the issuance of a consent order has been agreed upon by all...parties to the hearing, the proposed consent order shall be filed with the hearing...with a draft order adopting the consent decree and dismissing the case, for...

2010-01-01

407

A new ordered bed modular reactor concept  

Microsoft Academic Search

The Ordered Bed Modular Reactor (OBMR) is an advanced modular HTGR design in which the annular reactor core is filled with an ordered bed of fuel spheres. This arrangement allows fuel elements to be poured into the core cavity which is shaped so that an ordered bed is formed and to be discharged from the core through the opening holes

Jiafu Tian

2007-01-01

408

Birth Order and Risky Adolescent Behavior  

Microsoft Academic Search

It is commonly believed that birth order is an important determinant of success. However, previous studies in this area have failed to provide convincing evidence that birth order is related to test scores, education, or earnings. Using data from the National Longitudinal Survey of Youth--1979, we investigate the association between birth order and adolescent behaviors such as smoking, drinking, marijuana

Laura M. Argys; Daniel I. Rees; Susan L. Averett; Benjama Witoonchart

2006-01-01

409

Chiral second-order nonlinear optics  

Microsoft Academic Search

Organic second-order nonlinear optical (NLO) materials can be efficiently utilized in photonics devices for optical telecommunications and signal processing due to their high nonlinear response, processability, and low cost. Media with polar order are usually used to ensure the absence of the inversion symmetry required in second-order NLO. This study presents a method that results in creation of efficient chiral

Victor P. Ostroverkhov

2001-01-01

410

Strategic voting when aggregating partially ordered preferences  

Microsoft Academic Search

Preferences of a single agent are often partially ordered. For example, it may be hard to compare a novel with a biogra- phy. In such a situation, the agent may want the novel and the biography to be considered incomparable. We consider here how to aggregate the partially ordered preferences of multiple agents in order to return a set of

Maria Silvia Pini; Francesca Rossi; Kristen Brent Venable; Toby Walsh

2006-01-01

411

Sign Order in Argentine Sign Language  

ERIC Educational Resources Information Center

This article focuses on word order - the order of constituents in the sentence - as one way in which languages establish the relationship between a verb and its arguments. The spoken languages of the world have been classified into three, major word-order types: SVO, VSO, and SOV. Greenberg' work (1963) on language typology has been a stimulus to…

Massone, Maria Ignacia; Curiel, Monica

2004-01-01

412

Sign Order in Argentine Sign Language  

ERIC Educational Resources Information Center

|This article focuses on word order - the order of constituents in the sentence - as one way in which languages establish the relationship between a verb and its arguments. The spoken languages of the world have been classified into three, major word-order types: SVO, VSO, and SOV. Greenberg' work (1963) on language typology has been a stimulus to…

Massone, Maria Ignacia; Curiel, Monica

2004-01-01

413

Abel's Theorem Simplifies Reduction of Order  

ERIC Educational Resources Information Center

|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.|

Green, William R.

2011-01-01

414

Order Forecast of Cigarette Distribution Center  

Microsoft Academic Search

The thesis forecasts order of Cigarette Distribution Center by period, brand, district, from several dimensions. The thesis uses different models and analyses forecast results. When forecasting year's order amount, the mean accuracy of Logarithm Regression Model is highest, gets 98.45%. When forecasting month's order amount of cigarette, the thesis uses Genetic Algorithm (GA) to optimize BP neural networks, and overcomes

Yaohua Wu; Zuoling Song; Danyu Zhang

2007-01-01

415

Birth order as a market segmentation variable  

Microsoft Academic Search

Birth order studies have an established history in the academic world just as demographics have an established history in marketing. Discusses how birth order may influence several socio-economic mechanisms and thereby influence select consumption behaviors. As a likely influence of certain consumption behaviors, birth order may be useful in segmenting certain markets. Offers a corporate advertising example to demonstrate the

Reid P. Claxton

1995-01-01

416

New Orders in Manufacturing Point to Recovery  

Microsoft Academic Search

The latest order statistics indicate that Austria's manufacturing sector might climb out of the cyclical trough in the course of this year. New orders during the last few months were higher than during the same period in 1992 and the stock of orders in November exceeded last year's level for the first time during the current business cycle. Economic activity

Ewald Walterskirchen

1994-01-01

417

Metasearch with Ordered Tree Structured Patterns  

Microsoft Academic Search

Due to the rapid growth of tree structured data such as Web documents, ecient learn- ing from tree structured data becomes more and more important. We have proposed ordered tree structured patterns with internal structured variables, called ordered term trees, in order to represent structural features common to such tree structured data. In this paper, we propose a method for

Kazuhide Aikou; Yusuke Suzuki; Takayoshi Shoudai; Tetsuhiro Miyaharay

418

20 CFR 655.121 - Job orders.  

Code of Federal Regulations, 2012 CFR

...2012-04-01 2012-04-01 false Job orders. 655.121 Section 655.121... Prefiling Procedures § 655.121 Job orders. (a) Area of intended employment...Certification, the employer must submit a job order, Form ETA-790, to the SWA...

2012-04-01

419

Academic Libraries and Firm Order Vendors  

Microsoft Academic Search

Do academic limericks expect too much of their firm Order vendors? To find out, a number of current and former acquisitions Librarians ere conflicted. They provided opinions and insights regarding: What academics libraries wan1 from their firm order vendors, what acquisitions librarians think firm order vendors want from academic libraries, what vendors think academic libraries want, and what the vendors

Richard P Jasper

1991-01-01

420

Weak ordering—a new definition  

Microsoft Academic Search

A memory model for a shared memory, multiprocessor commonly and often implicitly assumed by programmers is that of sequential consistency. This model guarantees that all memory accesses will appear to execute atomically and in program order. An alternative model, weak ordering, offers greater performance potential. Weak ordering was first defined by Dubois, Scheurich and Briggs in terms of a set

Sarita V. Adve; Mark D. Hill

1990-01-01

421

4 CFR 21.4 - Protective orders.  

Code of Federal Regulations, 2013 CFR

...request of a party or on its own initiative, GAO may issue a protective order...ordinarily be subject to a protective order. GAO will review in camera all information not...the order by submitting an application to GAO, with copies furnished...

2013-01-01

422

Higher-order artificial neural networks  

SciTech Connect

The report investigates the storage capacity of an artificial neural network where the state of each neuron depends on quadratic correlations of all other neurons, i.e. a third order network. This is in contrast to a standard Hopfield network where the state of each single neuron depends on the state on every other neuron, without any correlations. The storage capacity of a third order network is larger than that for standard Hopfield by one order of N. However, the number of connections is also larger by an order of N. It is shown that the storage capacity per connection is identical for standard Hopfield and for this third order network.

Bengtsson, M.

1990-12-01

423

Crisis stability in the new world order  

SciTech Connect

This report gives a preliminary discussion of the crisis stability characteristics of the new world order through calculations calibrated for the current order. If finds that crisis stability indices have qualitatively similar behavior in the new order, but significantly more comforting values than in the old. The recent summit proposed significant cuts in MIRVed and heavy intercontinental ballistic missiles (ICBMs), and strategic weapons generally, that take the world into an apparently new order. This report gives a preliminary discussion of the crisis stability characteristics of that new order and of the interaction of offenses and defenses with stability indices in it.

Canavan, G.H.

1992-07-01

424

Application of one-dimensional nutation nuclear magnetic resonance to 51V in ferroelastic BiVO4.  

PubMed

The central line intensity of a spin I = 7/2, excited by a radio frequency (rf) pulse, is calculated by taking into account the first-order quadrupolar interaction during excitation. Thus, the result is valid for any ratio of quadrupolar coupling to pulse amplitude. The quadrupolar coupling of the nuclei vanadium 51V in a single crystal of ferroelastic BiVO4 is determined using this one-dimensional (1D) mutation method. PMID:7834322

Man, P P; Choh, S H; Fraissard, J

1994-08-01

425

SECOND ORDER OPTIMALITY CONDITIONS BASED ON PARABOLIC SECOND ORDER TANGENT SETS  

Microsoft Academic Search

In this paper we discuss second order optimality conditions in optimization problems subject to abstract constraints. Our analysis is based on various concepts of second order tangent sets and parametric duality. We introduce a condition, called second order regularity, under which there is no gap between the corresponding second order necessary and second order sucient conditions. We show that the

J. FR ED ERIC; ALEXANDER SHAPIROx

426

Hastatic Order in URu2Si2  

NASA Astrophysics Data System (ADS)

The hidden order that develops below 17.5K in URu2Si2 has eluded identification for twenty-five years. Here we show that the recent observation of Ising quasiparticles in URu2Si2 suggests a novel ``hastatic order'' (Latin:spear),with a two-component order parameter describing hybridization between electrons and the Ising 5f^2 states of the uranium atoms. Hastatic order breaks time-reversal symmetry by mixing states of different Kramers parity; this accounts for the magnetic anomalies observed in torque magnetometry and the pseudo-Goldstone mode observed in neutron scattering. Hastatic order is predicted to induce a basal-plane magnetic moment of order 0.01?B, a gap to longitudinal spin fluctuations that vanishes continuously at the first-order antiferromagnetic transition and a narrow resonant nematic feature in the scanning tunneling spectra.

Chandra, Premala; Coleman, Piers; Flint, Rebecca

2012-02-01

427

Fifth-order nonresonant Raman spectroscopy  

NASA Astrophysics Data System (ADS)

In this thesis, fifth-order nonresonant Raman spectroscopy is used to study the intermolecular motions of carbon disulfide so as to address fundamental questions about liquid dynamics. These questions, such as how diffusive dynamics (i.e. those involving structural change) emerge from fluctuations of individual molecules around their equilibrium positions, are directly addressed by fifth-order nonresonant Raman spectroscopy. This is due to the fifth-order signal's sensitivity to (and dependence upon) electrical or mechanical anharmonicity of the studied system, which is not a characteristic of lower-order spectroscopies. In this thesis, first it is shown that early attempts to measure the fifth-order nonresonant Raman signal of the low frequency motions of liquids were marred by the presence of lower-order cascading signals. These cascading signals do not depend on anharmonicity and thus do not contain the detailed molecular information that the fifth-order signal contains. It is shown that careful consideration of phase matching conditions allows one to suppress the lower-order cascading processes in favor of the desired fifth-order signal. In order to understand the measured fifth-order signals, both comparison to theory and signal processing is employed. An analysis of the full polarization dependence of the signal, based on early instantaneous normal mode analysis, is presented. A Fourier deconvolution of the measured signal is performed in order to isolate the portion of the fifth-order response most directly related to the details of liquid motion. Next, a heterodyne detection scheme, which allows for measurement of the sign and phase of the fifth-order nonresonant signal, is introduced. Heterodyne detected data from carbon disulfide is compared with simulations based on various theories. Most fruitfully, the data is compared with molecular dynamics simulations. Such comparison allows pinpointing the origin of key features of the measured signals.

Kaufman, Laura Jill

428

Ionic Conductivity of Block Copolymer Electrolytes in the Vicinity of Order?Disorder and Order?Order Transitions  

SciTech Connect

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.

Wanakule, Nisita S.; Panday, Ashoutosh; Mullin, Scott A.; Gann, Eliot; Hexemer, Alex; Balsara, Nitash P.; (UCB); (LBNL)

2009-09-15

429

Sequence of disorder-order and order-order transitions accompanying the formation of M2X superstructures  

NASA Astrophysics Data System (ADS)

The symmetry analysis of the trigonal, cubic, and tetragonal M2X superstructures formed in strongly nonstoichiometric compounds MX y with the B1 structure has been performed. Disorder-order MX y ? M2X transition channels have been revealed. It has been shown that three physically allowable sequences of transitions associated with the formation of ordered M2X phases and order-order transitions between them are possible in nonstoichiometric carbides and nitrides MX y of the transition metals of group IV with a decrease in the temperature.

Gusev, A. I.

2010-02-01

430

78 FR 46823 - Kiwifruit Grown in California; Proposed Amendments to Marketing Order 920 and Referendum Order  

Federal Register 2010, 2011, 2012, 2013

...FURTHER INFORMATION CONTACT: Kathleen Bright, Marketing Order and Agreement...consumers on a global basis. Approval...research to the order is expected to...agreements and orders may be viewed...FURTHER INFORMATION CONTACT section....

2013-08-02

431

Order Parameters for Two-Dimensional Networks  

NASA Astrophysics Data System (ADS)

We derive methods that explain how to quantify the amount of order in ``ordered'' and ``highly ordered'' porous arrays. Ordered arrays from bee honeycomb and several from the general field of nanoscience are compared. Accurate measures of the order in porous arrays are made using the discrete pair distribution function (PDF) and the Debye-Waller Factor (DWF) from 2-D discrete Fourier transforms calculated from the real-space data using MATLAB routines. An order parameter, OP3, is defined from the PDF to evaluate the total order in a given array such that an ideal network has the value of 1. When we compare PDFs of man-made arrays with that of our honeycomb we find OP3=0.399 for the honeycomb and OP3=0.572 for man's best hexagonal array. The DWF also scales with this order parameter with the least disorder from a computer-generated hexagonal array and the most disorder from a random array. An ideal hexagonal array normalizes a two-dimensional Fourier transform from which a Debye-Waller parameter is derived which describes the disorder in the arrays. An order parameter S, defined by the DWF, takes values from [0, 1] and for the analyzed man-made array is 0.90, while for the honeycomb it is 0.65. This presentation describes methods to quantify the order found in these arrays.

Kaatz, Forrest; Bultheel, Adhemar; Egami, Takeshi

2007-10-01

432

Two variants of minimum discarded fill ordering  

SciTech Connect

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.

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

433

Synchronization of chaotic systems with different order.  

PubMed

The chaotic synchronization of third-order systems and second-order driven oscillator is studied in this paper. Such a problem is related to synchronization of strictly different chaotic systems. We show that dynamical evolution of second-order driven oscillators can be synchronized with the canonical projection of a third-order chaotic system. In this sense, it is said that synchronization is achieved in reduced order. Duffing equation is chosen as slave system whereas Chua oscillator is defined as master system. The synchronization scheme has nonlinear feedback structure. The reduced-order synchronization is attained in a practical sense, i.e., the difference e=x(3)-x(1)(') is close to zero for all time t> or =t(0)> or =0, where t(0) denotes the time of the control activation. PMID:11909231

Femat, Ricardo; Solís-Perales, Gualberto

2002-03-05

434

Second-order dust acoustic wave theory  

NASA Astrophysics Data System (ADS)

A second-order perturbation theory for non-dispersive, undamped dust acoustic waves is presented. The analysis leads to a second-order wave equation with source terms consisting of (nonlinear) products of first-order terms. The nonlinear effects included in this analysis might be useful in explaining the non-sinusoidal waveforms that are observed with large-amplitude, self-excited dust acoustic waves.

Merlino, Robert L.

2012-03-01

435

Order Scheduling Multi-objective Optimization  

Microsoft Academic Search

The research of multi-product manufacturing scheduling under the circumstances of multi-orders is not profound so far, therefore, this paper proposed a new multi-objective optimization model which was base on orders. The objectives of this model include maximization of profit and balanced production. In order to realize balanced production, we use a method which could minimize various resource consumption in consecutive

Xin-lin Chen; Shuang-wu Zhang; Xiang-gang Wang

2009-01-01

436

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.

437

Convergence and Ordering of Kohonen's Batch Map  

Microsoft Academic Search

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

Yizong Cheng

1997-01-01

438

Second-Order Algebraic Theories - (Extended Abstract)  

Microsoft Academic Search

\\u000a Fiore and Hur [10] recently introduced a conservative extension of universal algebra and equational logic from first to second\\u000a order. Second-order universal algebra and second-order equational logic respectively provide a model theory and a formal deductive\\u000a system for languages with variable binding and parameterised metavariables. This work completes the foundations of the subject\\u000a from the viewpoint of categorical algebra. Specifically,

Marcelo P. Fiore; Ola Mahmoud

2010-01-01

439

Understanding fractional-order surface plasmons.  

PubMed

We show experimentally that diffraction-induced surface plasmon excitation can mimic enhanced transmission and cause a highly sensitive modulation by the coherent interference between zero-order and reflected first-order diffraction in select regions of the terahertz spectrum. Based on the study of a one-dimensional metallic grating, we obtain the physical mechanisms of the fractional-order surface plasmon resonances observed with the two-dimensional grating of the metallic hole array. PMID:22048370

Yang, Yuping; Grischkowsky, Daniel

2011-11-01

440

Epsilon Negative Zeroth-Order Resonator Antenna  

Microsoft Academic Search

It is confirmed that zeroth-order resonance appears in the epsilon negative (ENG) meta-structured transmission line (MTL) as well as in the conventional double negative (DNG) MTL. The zeroth-order resonant characteristics are described using dispersion relation of ENG MTL based on Bloch and Floquet theory. Appling the novel concept of the ENG zeroth-order resonator (ZOR), an ENG ZOR antenna is proposed.

Jae-Hyun Park; Young-Ho Ryu; Jae-Gon Lee; Jeong-Hae Lee

2007-01-01

441

Second-order optic flow processing.  

PubMed

Optic flow-large-field rotational and radial motion-is processed as efficiently as translational motion for first-order (luminance-defined) stimuli. However, it has been suggested recently that the same pattern does not hold for second-order (e.g. contrast-defined) stimuli. We used random dot kinematogram (RDK) stimuli to determine whether global processing of optic flow is as efficient as processing of global translational motion for both first- and second-order stimuli. For first-order stimuli, we found that coherence thresholds for radial and rotational motion were equivalent to thresholds for translational motion, supporting previous findings. For second-order stimuli we found, firstly, that given sufficient contrast, second-order optic flow can be processed as efficiently as first-order optic flow and, secondly, that rotational and translational second-order motion are processed with equal efficiency. This contradicts the suggestion that there is a loss of efficiency between integration of second-order global motion and second-order optic flow. The third interesting finding was that the processing of radial second-order motion appears to suffer from a deficit that is dependent upon both the contrast and spatial extent of the stimulus. Further experiments discounted the possibility that the observed deficit is caused by a centrifugal or centripetal bias, but demonstrated that a longer temporal integration period for radial second-order motion is responsible for the observed difference. For durations of approximately 850ms, all three types of motion are processed with equal efficiency. PMID:17462696

Aaen-Stockdale, Craig; Ledgeway, Tim; Hess, Robert F

2007-04-25

442

Feedback and efficiency in limit order markets  

NASA Astrophysics Data System (ADS)

A consistency criterion for price impact functions in limit order markets is proposed that prohibits chain arbitrage exploitation. Both the bid-ask spread and the feedback of sequential market orders of the same kind onto both sides of the order book are essential to ensure consistency at the smallest time scale. All the stocks investigated in Paris Stock Exchange have consistent price impact functions.

Challet, Damien

2008-06-01

443

Kinetics of an order-disorder transition  

SciTech Connect

Novel computer simulations are described of the time evolution of an ordering model binary alloy following quenching from a disordered state at a high temperature. The results are interpreted with use of ideas of Lifshitz and of Cahn and Allen; the ordering process is described by a kinetic equation for the motion of the walls separating domains with different orderings. The characteristic length increases as t/sup 1/2/, and the structure function scales as kt/sup 1/2/.

Phani, M.K.; Lebowitz, J.L.; Kalos, M.H.; Penrose, O.

1980-08-04

444

Computerized physician order entry in critical care.  

PubMed

Computerized physician order entry means prescribing of medication and ordering laboratory tests or radiology examinations in an electronic way instead of using paper forms. In itself, it offers advantages such as legible orders, faster order completion, inventory management and automatic billing. If combined with clinical decision support, the real benefits of CPOE become apparent in the first place by prevention of medication errors and adverse drug events. On the contrary, if CPOE configuration is not done carefully, adverse drug events can be facilitated. Therefore, and for reasons of end-user acceptance, implementation is challenging. CPOE has the potential for significant economic saving. However, the initial implementation cost is high. PMID:19449614

Colpaert, Kirsten; Decruyenaere, Johan

2009-03-01

445

Second order geodesic corrections to cosmic shear  

SciTech Connect

We consider the impact of second order corrections to the geodesic equation governing gravitational lensing. We start from the full second order metric, including scalar, vector, and tensor perturbations, and retain all relevant contributions to the cosmic shear corrections that are second order in the gravitational potential. The relevant terms are: the nonlinear evolution of the scalar gravitational potential, the Born correction, and lens-lens coupling. No other second order terms contribute appreciably to the lensing signal. Since ray-tracing algorithms currently include these three effects, this derivation serves as rigorous justification for the numerical predictions.

Dodelson, Scott [Particle Astrophysics Center Fermi National Accelerator Laboratory, Batavia, Illinois 60510-0500 (United States); Department of Astronomy and Astrophysics, University of Chicago, Chicago, Illinois 60637-1433 (United States); Department of Physics and Astronomy, Northwestern University, Evanston, Illinois 60208 (United States); Kolb, Edward W. [Particle Astrophysics Center Fermi National Accelerator Laboratory, Batavia, Illinois 60510-0500 (United States); Department of Astronomy and Astrophysics, University of Chicago, Chicago, Illinois 60637-1433 (United States); Matarrese, S. [Dipartimento di Fisica 'G. Galilei', Universita di Padova (Italy); INFN, Sezione di Padova, via Marzolo 8, I-35131 (Italy); Riotto, A. [Dipartimento di Fisica 'G. Galilei', Universita di Padova (Italy); Zhang Pengjie [Particle Astrophysics Center Fermi National Accelerator Laboratory, Batavia, Illinois 60510-0500 (United States)

2005-11-15

446

Second order hydrodynamic coefficients from kinetic theory  

SciTech Connect

In a relativistic setting, hydrodynamic calculations which include shear viscosity (which is first order in an expansion in gradients of the flow velocity) are unstable and acausal unless they also include terms to second order in gradients. To date such terms have only been computed in supersymmetric N=4 super-Yang-Mills theory at infinite coupling. Here we compute these second-order hydrodynamic coefficients in weakly coupled QCD, perturbatively to leading order in the QCD coupling, using kinetic theory. We also compute them in QED and scalar {lambda}{phi}{sup 4} theory.

York, Mark Abraao; Moore, Guy D. [McGill University, Department of Physics, 3600 rue University, Montreal QC H3A 2T8 (Canada)

2009-03-01

447

Selling by Mail Order. Marketing Series.  

National Technical Information Service (NTIS)

This publication provides basic information on how to run a successful mail order business. It includes information on selecting, pricing, testing and writing effective advertisements for your products.

2009-01-01

448

Duplicate Orders: An Unintended Consequence of Computerized provider/physician order entry (CPOE) Implementation  

PubMed Central

Objective Computerized provider/physician order entry (CPOE) with clinical decision support (CDS) is designed to improve patient safety. However, a number of unintended consequences which include duplicate ordering have been reported. The objective of this time-series study was to characterize duplicate orders and devise strategies to minimize them. Methods Time series design with systematic weekly sampling for 84 weeks. Each week we queried the CPOE database, downloaded all active orders onto a spreadsheet, and highlighted duplicate orders. We noted the following details for each duplicate order: time, order details (e.g. drug, dose, route and frequency), ordering prescriber, including position and role, and whether the orders originated from a single order or from an order set (and the name of the order set). This analysis led to a number of interventions, including changes in: order sets, workflow, prescriber training, pharmacy procedures, and duplicate alerts. Results Duplicates were more likely to originate from different prescribers than from same prescribers; and from order sets than from single orders. After interventions, there was an 84.8% decrease in the duplication rate from weeks 1 to 84 and a 94.6% decrease from the highest (1) to the lowest week (75). Currently, we have negligible duplicate orders. Conclusions Duplicate orders can be a significant unintended consequence of CPOE. By analyzing these orders, we were able to devise and implement generalizable strategies that significantly reduced them. The incidence of duplicate orders before CPOE implementation is unknown, and our data originate from a weekly snapshot of active orders, which serves as a sample of total active orders. Thus, it should be noted that this methodology likely under-reports duplicate orders.

Magid, S.; Forrer, C.; Shaha, S.

2012-01-01

449

Milk Marketing Order Winners and Losers  

Microsoft Academic Search

Do milk marketing orders affect various demographic groups differently? To answer this question, we use supermarket scanner data to estimate an incomplete demand system for dairy products. Based on these estimates, we simulate substitution effects among dairy products and the welfare impacts of price changes resulting from changes in milk marketing orders for various consumer groups. While we find little

Hayley H. Chouinard; David E. Davis; Jeffrey T. LaFrance; Jeffrey M. Perloff

2006-01-01

450

Reduced-order estimation Part 1. Filtering  

Microsoft Academic Search

This paper presents a method for designing an ‘optimum’ unbiased reduced-order filter. For the proposed approach to work, the order of the filter must be greater than a certain minimum determined by the number of independent observations of the system available. The filler is much like a Luenberger observer for the state to be estimated, but with parameters optimized with

KRISHAN M. NAGPAL; RONALD E. HELMICK; CRAIG S. SIMS

1987-01-01

451

Reduced order filtering in an H? setting  

Microsoft Academic Search

In this paper we consider the problem of estimation with reduced order filter\\/observers with an H? type performance criterion. For a give n-th order linear system, we give necessary and sufficient conditions for there to exist an \\

Hansil Kim; Craig S. Sims; K. M. Nagpal

1992-01-01

452

Ordering of magnetic nanoparticles in bilayer structures  

Microsoft Academic Search

In this study, we predict crystalline ordering of magnetic nanoparticles in a bilayer structure where only magnetic dipole interaction is taken into account. Estimates show that the two-dimensional lattice structure can be observed in the liquid nitrogen temperature regime. The results can be extended to magnetic nanoparticle multilayers. In addition, the study implies an order-disorder phase transition of the magnetic

Haiwen Xi; Xiaobin Wang; Yiran Chen; Pat J. Ryan

2009-01-01

453

Enhanced ordering temperatures in antiferromagnetic manganite superlattices  

SciTech Connect

The disorder inherent to doping by cation substitution in the complex oxides can have profound effects on collective ordered states. Here, we demonstrate that cation-site ordering achieved via digital synthesis techniques can dramatically enhance the antiferromagnetic ordering temperatures of manganite films. Cation-ordered (LaMnO3)m/(SrMnO3)2m superlattices exhibit N el temperatures (TN) that are the highest of any La1-xSrxMnO3 compound, ~70 K greater than compositionally equivalent randomly doped La1/3Sr2/3MnO3. The antiferromagnetic order is A-type, consisting of in-plane double-exchange-mediated ferromagnetic sheets coupled antiferromagnetically along the out-of-plane direction. Via synchrotron x-ray scattering, we have discovered an in-plane structural modulation that reduces the charge itinerancy and hence the ordering temperature within the ferromagnetic sheets, thereby limiting TN. This modulation is mitigated and driven to long wavelengths by cation ordering, enabling the higher TN values of the superlattices. These results provide insight into how cation-site ordering can enhance cooperative behavior in oxides through subtle structural phenomena.

May, Stephen J. [Argonne National Laboratory (ANL); Robertson, Lee [ORNL; Ryan, P J [Ames Laboratory; Kim, J.-W. [Ames Laboratory; Santos, Tiffany S. [Argonne National Laboratory (ANL); Karapetrova, Evgenia [University of Illinois, Urbana-Champaign; Zarestky, Jerel L. [Ames Laboratory; Zhai, X. [University of Illinois, Urbana-Champaign; Te velthuis, Suzanne G. [Argonne National Laboratory (ANL); Eckstein, James N. [University of Illinois, Urbana-Champaign; Bader, S. D. [Argonne National Laboratory (ANL); Bhattacharya, Anand [Argonne National Laboratory (ANL)

2009-01-01

454

EXECUTIVE ORDER FAMILY COURT INDIGENT COUNSEL  

Microsoft Academic Search

Pursuant to the authority vested in me by G. L. 1956 (1985 Reenactment) § 8-15-2, and in order to provide competent representation, to ensure that the distribution of court appointments is made in a fair and equitable fashion, to provide a uniform and efficient system for making such appointments, and to protect the public interest, it is hereby ordered that

Supreme Court

2004-01-01

455

The likely organizational order of advanced intelligences  

Microsoft Academic Search

Civilizations, highly advanced in science and technology, are bound to possess also a highly refined organizational order. Otherwise they would not have survived. The human analogy supports this proposition. Though still beset by intra-species conflict, our world is already pregnant with tendencies moving it toward a global political and economic order. Contact with a superior extraterrestrial intelligence would therefore serve

Peter Schenkel

1991-01-01

456

The need for a universal humanitarian order  

Microsoft Academic Search

Purpose – Within the context of an international conference dealing with global challenges, the Atlantic Community and the outlook for international order organized by Webster University, Geneva (Switzerland), to propose an approach to strengthening the international order by reviving the global responsibility to abide by fundamental humanitarian rules. Design\\/methodology\\/approach – The twentieth century presented a very disturbing catalog of violations

Michel Veuthey

2005-01-01

457

Air Force Technical Order Management System (AFTOMS)  

Microsoft Academic Search

The author describes the Air Force Technical Order Management System (AFTOMS) program for modernizing the US Air Force's technical-order infrastructure. He describes the AFTOMS program management direction and policy, the AFTOMS concept, and the relationship between AFTOMS and the Air Force and Department of Defense computer-aided acquisition and logistics support (CALS) initiatives. Also included is a discussion of strategies for

1989-01-01

458

33 CFR 20.606 - Protective orders.  

Code of Federal Regulations, 2013 CFR

...protective order, the ALJ may let him or her make all or part of the showing of good cause in camera. The ALJ shall record any proceedings in camera. If he or she enters a protective order, he or she shall seal any proceedings so...

2013-07-01

459

High School Order and Academic Achievement.  

ERIC Educational Resources Information Center

In contrast to public opinion, the relationship between school order and achievement is neither simple nor certain. While research shows individuals who misbehave perform poorly in school, it has not made clear why. Further, the evidence on order and achievement at the school level is even more limited. One inference drawn here is that failure to…

Gaddy, Gary D.

460

High order curvature Adaptive Optics revisited  

Microsoft Academic Search

High dynamic range imaging is defined as the search for very faint objects around bright ones. This pushes requirements on every aspect of telescope and instrument design. Coronography (lyot and phase), high order adaptive optics, apodised pupils may all have a role to play in this endeavor. High order adaptive optics systems have conventionnaly been thought of as Shack-Hartman\\/piezostack devices

Olivier Lai

2002-01-01

461

Learning Compound Order: Towards a Functional Explanation  

Microsoft Academic Search

This project investigates the problem of learning compound order, from an interdisciplinaryperspective. Formal theories of linguistics have not addressed the question of why the constituentsforming verbal compounds are ordered the way they are. Research in linguistic typology andlanguage acquisition is critically examined, demonstrating the importance of the study of mentalrepresentation in explaining the development of morphological competence. Experimental resultsare reported

Scott McDonald

1995-01-01

462

Orderly marketing: reality, rhetoric or myth?  

Microsoft Academic Search

Purpose – The purpose of this paper is to examine the meaning and content of the term “orderly marketing” as it was adopted by Western Canadian farm leaders in the 1920s, and to determine whether the expected results of “orderly marketing”, as they were enunciated by farm leaders, were met. Design\\/methodology\\/approach – The paper examines the critique that farm leaders

Paul D. Earl

2011-01-01

463