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Sample records for spin rotation technique

  1. Muon spin rotation and other microscopic probes of spin-glass dynamics

    International Nuclear Information System (INIS)

    MacLaughlin, D.E.

    1980-01-01

    A number of different microscopic probe techniques have been employed to investigate the onset of the spin-glass state in dilute magnetic alloys. Among these are Moessbauer-effect spectroscopy, neutron scattering, ESR of the impurity spins, host NMR and, most recently, muon spin rotation and depolarization. Spin probes yield information on the microscopic static and dynamic behavior of the impurity spins, and give insight into both the spin freezing process and the nature of low-lying excitations in the ordered state. Microscopic probe experiments in spin glasses are surveyed, and the unique advantages of muon studies are emphasized

  2. Effect of spin rotation coupling on spin transport

    International Nuclear Information System (INIS)

    Chowdhury, Debashree; Basu, B.

    2013-01-01

    We have studied the spin rotation coupling (SRC) as an ingredient to explain different spin-related issues. This special kind of coupling can play the role of a Dresselhaus like coupling in certain conditions. Consequently, one can control the spin splitting, induced by the Dresselhaus like term, which is unusual in a semiconductor heterostructure. Within this framework, we also study the renormalization of the spin-dependent electric field and spin current due to the k → ⋅p → perturbation, by taking into account the interband mixing in the rotating system. In this paper we predict the enhancement of the spin-dependent electric field resulting from the renormalized spin rotation coupling. The renormalization factor of the spin electric field is different from that of the SRC or Zeeman coupling. The effect of renormalized SRC on spin current and Berry curvature is also studied. Interestingly, in the presence of this SRC-induced SOC it is possible to describe spin splitting as well as spin galvanic effect in semiconductors. -- Highlights: •Studied effect of spin rotation coupling on the spin electric field, spin current and Berry curvature. •In the k → ⋅p → framework we study the renormalization of spin electric field and spin current. •For an inertial system we have discussed the spin splitting. •Expression for the Berry phase in the inertial system is discussed. •The inertial spin galvanic effect is studied

  3. Effect of spin rotation coupling on spin transport

    Energy Technology Data Exchange (ETDEWEB)

    Chowdhury, Debashree, E-mail: debashreephys@gmail.com; Basu, B., E-mail: sribbasu@gmail.com

    2013-12-15

    We have studied the spin rotation coupling (SRC) as an ingredient to explain different spin-related issues. This special kind of coupling can play the role of a Dresselhaus like coupling in certain conditions. Consequently, one can control the spin splitting, induced by the Dresselhaus like term, which is unusual in a semiconductor heterostructure. Within this framework, we also study the renormalization of the spin-dependent electric field and spin current due to the k{sup →}⋅p{sup →} perturbation, by taking into account the interband mixing in the rotating system. In this paper we predict the enhancement of the spin-dependent electric field resulting from the renormalized spin rotation coupling. The renormalization factor of the spin electric field is different from that of the SRC or Zeeman coupling. The effect of renormalized SRC on spin current and Berry curvature is also studied. Interestingly, in the presence of this SRC-induced SOC it is possible to describe spin splitting as well as spin galvanic effect in semiconductors. -- Highlights: •Studied effect of spin rotation coupling on the spin electric field, spin current and Berry curvature. •In the k{sup →}⋅p{sup →} framework we study the renormalization of spin electric field and spin current. •For an inertial system we have discussed the spin splitting. •Expression for the Berry phase in the inertial system is discussed. •The inertial spin galvanic effect is studied.

  4. CONFERENCE: Muon spin rotation

    Energy Technology Data Exchange (ETDEWEB)

    Karlsson, Erik

    1986-11-15

    An international physics conference centred on muons without a word about leptons, weak interactions, EMC effects, exotic decay modes or any other standard high energy physics jargon. Could such a thing even have been imagined ten years ago? Yet about 120 physicists and chemists from 16 nations gathered at the end of June in Uppsala (Sweden) for their fourth meeting on Muon Spin Rotation, Relaxation and Resonance, without worrying about the muon as an elementary particle. This reflects how the experimental techniques based on the muon spin interactions have reached maturity and are widely recognized by condensed matter physicists and specialized chemists as useful tools.

  5. Muon spin rotation in superconductors

    International Nuclear Information System (INIS)

    Gladisch, M.; Orth, H.; Putlitz, G. zu; Wahl, W.; Wigand, M.; Herlach, D.; Seeger, A.; Metz, H.; Teichler, H.

    1979-01-01

    By means of the muon spin rotation technique (μ + SR), the temperature dependence of the magnetic field inside the normal-conducting domains of high-purity tantalum crystals in the intermediate state has been measured in the temperature range 2.36 K + SR. Possible applications of these findings to the study of long-range diffusion of positive muons at low temperatures are indicated. (Auth.)

  6. Inertial rotation measurement with atomic spins: From angular momentum conservation to quantum phase theory

    Science.gov (United States)

    Zhang, C.; Yuan, H.; Tang, Z.; Quan, W.; Fang, J. C.

    2016-12-01

    Rotation measurement in an inertial frame is an important technology for modern advanced navigation systems and fundamental physics research. Inertial rotation measurement with atomic spin has demonstrated potential in both high-precision applications and small-volume low-cost devices. After rapid development in the last few decades, atomic spin gyroscopes are considered a promising competitor to current conventional gyroscopes—from rate-grade to strategic-grade applications. Although it has been more than a century since the discovery of the relationship between atomic spin and mechanical rotation by Einstein [Naturwissenschaften, 3(19) (1915)], research on the coupling between spin and rotation is still a focus point. The semi-classical Larmor precession model is usually adopted to describe atomic spin gyroscope measurement principles. More recently, the geometric phase theory has provided a different view of the rotation measurement mechanism via atomic spin. The theory has been used to describe a gyroscope based on the nuclear spin ensembles in diamond. A comprehensive understanding of inertial rotation measurement principles based on atomic spin would be helpful for future applications. This work reviews different atomic spin gyroscopes and their rotation measurement principles with a historical overlook. In addition, the spin-rotation coupling mechanism in the context of the quantum phase theory is presented. The geometric phase is assumed to be the origin of the measurable rotation signal from atomic spins. In conclusion, with a complete understanding of inertial rotation measurements using atomic spin and advances in techniques, wide application of high-performance atomic spin gyroscopes is expected in the near future.

  7. COMMISSIONING SPIN ROTATORS IN RHIC

    International Nuclear Information System (INIS)

    MACKAY, W.W.; AHRENS, L.; BAI, M.; COURANT, E.D.; FISCHER, W.; HUANG, H.; LUCCIO, A.; MONTAG, C.; PILAT, F.; PTITSYN, V.; ROSER, T.; SATOGATA, T.; TRBOJEVIC, D.; VANZIEJTS, J.

    2003-01-01

    During the summer of 2002, eight superconducting helical spin rotators were installed into RHIC in order to control the polarization directions independently at the STAR and PHENIX experiments. Without the rotators, the orientation of polarization at the interaction points would only be vertical. With four rotators around each of the two experiments, we can rotate either or both beams from vertical into the horizontal plane through the interaction region and then back to vertical on the other side. This allows independent control for each beam with vertical, longitudinal, or radial polarization at the experiment. In this paper, we present results from the first run using the new spin rotators at PHENIX

  8. Coherent spin-rotational dynamics of oxygen superrotors

    Science.gov (United States)

    Milner, Alexander A.; Korobenko, Aleksey; Milner, Valery

    2014-09-01

    We use state- and time-resolved coherent Raman spectroscopy to study the rotational dynamics of oxygen molecules in ultra-high rotational states. While it is possible to reach rotational quantum numbers up to N≈ 50 by increasing the gas temperature to 1500 K, low population levels and gas densities result in correspondingly weak optical response. By spinning {{O}2} molecules with an optical centrifuge, we efficiently excite extreme rotational states with N≤slant 109 in high-density room temperature ensembles. Fast molecular rotation results in the enhanced robustness of the created rotational wave packets against collisions, enabling us to observe the effects of weak spin-rotation coupling in the coherent rotational dynamics of oxygen. The decay rate of spin-rotational coherence due to collisions is measured as a function of the molecular angular momentum and its dependence on the collisional adiabaticity parameter is discussed. We find that at high values of N, the rotational decoherence of oxygen is much faster than that of the previously studied non-magnetic nitrogen molecules, pointing at the effects of spin relaxation in paramagnetic gases.

  9. Helical spin rotators and snakes for RHIC

    International Nuclear Information System (INIS)

    Ptitsin, V.I.; Shatunov, Yu.M.; Peggs, S.

    1995-01-01

    The RHIC collider, now under construction at BNL, will have the possibility of polarized proton-proton collisions up to a beam energy of 250 Gev. Polarized proton beams of such high energy can be only obtained with the use of siberian snakes, a special kind of spin rotator that rotates the particle spin by 180 degree around an axis lying in the horizontal plane. Siberian snakes help to preserve the beam polarization while numerous spin depolarizing resonances are crossed, during acceleration. In order to collide longitudinally polarized beams, it is also planned to install spin rotators around two interaction regions. This paper discusses snake and spin rotator designs based on sequences of four helical magnets. The schemes that were chosen to be applied at RHIC are presented

  10. Spin current pumped by a rotating magnetic field in zigzag graphene nanoribbons

    International Nuclear Information System (INIS)

    Wang, J; Chan, K S

    2010-01-01

    We study electron spin resonance in zigzag graphene nanoribbons by applying a rotating magnetic field on the system without any bias. By using the nonequilibrium Green's function technique, the spin-resolved pumped current is explicitly derived in a rotating reference frame. The pumped spin current density increases with the system size and the intensity of the transverse rotating magnetic field. For graphene nanoribbons with an even number of zigzag chains, there is a nonzero pumped charge current in addition to the pumped spin current owing to the broken spatial inversion symmetry of the system, but its magnitude is much smaller than the spin current. The short-ranged static disorder from either impurities or defects in the ribbon can depress the spin current greatly due to the localization effect, whereas the long-ranged disorder from charge impurities can avoid inter-valley scattering so that the spin current can survive in the strong disorder for the single-energy mode.

  11. Wiggler as spin rotators for RHIC

    International Nuclear Information System (INIS)

    Luccio, A.; Conte, M.

    1993-01-01

    The spin of a polarized particle in a circular accelerator can be rotated with an arrangement of dipoles with field mutually perpendicular and perpendicular to the orbit. To achieve spin rotation, a given field integral value is required. The device must be designed in a way that the particle orbit is distorted as little as possible. It is shown that wigglers with many periods are suitable to achieve spin rotation with minimum orbit distortions. Wigglers are also more compact than more established structures and will use less electric power. Additional advantages include their use for non distructive beam diagnostics. Results are given for the Relativistic Heavy Ion Collider (RHIC) in the polarized proton mode

  12. Spin-rotation interaction of alkali-metal endash He-atom pairs

    International Nuclear Information System (INIS)

    Walker, T.G.; Thywissen, J.H.; Happer, W.

    1997-01-01

    A treatment of the spin-rotation coupling between alkali-metal atoms and He atoms is presented. Rotational distortions are accounted for in the wave function using a Coriolis interaction in the rotating frame. The expectation value of the spin-orbit interaction gives values of the spin-rotation coupling that explain previous experimental results. For spin-exchange optical pumping, the results suggest that lighter alkali-metal atoms would be preferred spin-exchange partners, other factors being equal. copyright 1997 The American Physical Society

  13. Magnetic pseudo-fields in a rotating electron-nuclear spin system

    Science.gov (United States)

    Wood, A. A.; Lilette, E.; Fein, Y. Y.; Perunicic, V. S.; Hollenberg, L. C. L.; Scholten, R. E.; Martin, A. M.

    2017-11-01

    Analogous to the precession of a Foucault pendulum observed on the rotating Earth, a precessing spin observed in a rotating frame of reference appears frequency-shifted. This can be understood as arising from a magnetic pseudo-field in the rotating frame that nevertheless has physically significant consequences, such as the Barnett effect. To detect these pseudo-fields, a rotating-frame sensor is required. Here we use quantum sensors, nitrogen-vacancy (NV) centres, in a rapidly rotating diamond to detect pseudo-fields in the rotating frame. Whereas conventional magnetic fields induce precession at a rate proportional to the gyromagnetic ratio, rotation shifts the precession of all spins equally, and thus primarily affect 13C nuclear spins in the sample. We are thus able to explore these effects via quantum sensing in a rapidly rotating frame, and define a new approach to quantum control using rotationally induced nuclear spin-selective magnetic fields. This work provides an integral step towards realizing precision rotation sensing and quantum spin gyroscopes.

  14. Snakes and spin rotators

    International Nuclear Information System (INIS)

    Lee, S.Y.

    1990-01-01

    The generalized snake configuration offers advantages of either shorter total snake length and smaller orbit displacement in the compact configuration or the multi-functions in the split configuration. We found that the compact configuration can save about 10% of the total length of a snake. On other hand, the spilt snake configuration can be used both as a snake and as a spin rotator for the helicity state. Using the orbit compensation dipoles, the spilt snake configuration can be located at any distance on both sides of the interaction point of a collider provided that there is no net dipole rotation between two halves of the snake. The generalized configuration is then applied to the partial snake excitation. Simple formula have been obtained to understand the behavior of the partial snake. Similar principle can also be applied to the spin rotators. We also estimate the possible snake imperfections are due to various construction errors of the dipole magnets. Accuracy of field error of better than 10 -4 will be significant. 2 refs., 5 figs

  15. Rotational Invariance of the 2d Spin - Spin Correlation Function

    Science.gov (United States)

    Pinson, Haru

    2012-09-01

    At the critical temperature in the 2d Ising model on the square lattice, we establish the rotational invariance of the spin-spin correlation function using the asymptotics of the spin-spin correlation function along special directions (McCoy and Wu in the two dimensional Ising model. Harvard University Press, Cambridge, 1973) and the finite difference Hirota equation for which the spin-spin correlation function is shown to satisfy (Perk in Phys Lett A 79:3-5, 1980; Perk in Proceedings of III international symposium on selected topics in statistical mechanics, Dubna, August 22-26, 1984, JINR, vol II, pp 138-151, 1985).

  16. Spins of superdeformed rotational bands in Tl isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Dadwal, Anshul; Mittal, H.M. [Dr. B.R. Ambedkar National Institute of Technology, Jalandhar (India)

    2017-01-15

    The two-parameter model defined for even-even nuclei viz. soft-rotor formula is used to assign the band-head spin of the 17 rotational bands in Tl isotopes. The least-squares fitting method is employed to obtain the spins of these bands in the A ∝ 190 mass region. The calculated transition energies are found to depend sensitively on the proposed spin. Whenever a correct spin assignment is made, the calculated and experimental transition energies coincide very well. The dynamic moment of inertia is also calculated and its variation with rotational frequency is explored. (orig.)

  17. Spin currents of charged Dirac particles in rotating coordinates

    Science.gov (United States)

    Dayi, Ö. F.; Yunt, E.

    2018-03-01

    The semiclassical Boltzmann transport equation of charged, massive fermions in a rotating frame of reference, in the presence of external electromagnetic fields is solved in the relaxation time approach to establish the distribution function up to linear order in the electric field in rotating coordinates, centrifugal force and the derivatives. The spin and spin current densities are calculated by means of this distribution function at zero temperature up to the first order. It is shown that the nonequilibrium part of the distribution function yields the spin Hall effect for fermions constrained to move in a plane perpendicular to the angular velocity and magnetic field. Moreover it yields an analogue of Ohm's law for spin currents whose resistivity depends on the external magnetic field and the angular velocity of the rotating frame. Spin current densities in three-dimensional systems are also established.

  18. Numerical studies of Siberian snakes and spin rotators for RHIC

    International Nuclear Information System (INIS)

    Luccio, A.

    1995-01-01

    For the program of polarized protons in RHIC, two Siberian snakes and four spin rotators per ring will be used. The Snakes will produce a complete spin flip. Spin Rotators, in pairs, will rotate the spin from the vertical direction to the horizontal plane at a given insertion, and back to the vertical after the insertion. Snakes, 180 degrees apart and with their axis of spin precession at 90 degrees to each other, are an effective means to avoid depolarization of the proton beam in traversing resonances. Classical snakes and rotators are made with magnetic solenoids or with a sequence of magnetic dipoles with fields alternately directed in the radial and vertical direction. Another possibility is to use helical magnets, essentially twisted dipoles, in which the field, transverse the axis of the magnet, continuously rotates as the particles proceed along it. After some comparative studies, the authors decided to adopt for RHIC an elegant solution with four helical magnets both for the snakes and the rotators proposed by Shatunov and Ptitsin. In order to simplify the construction of the magnets and to minimize cost, four identical super conducting helical modules will be used for each device. Snakes will be built with four right-handed helices. Spin rotators with two right-handed and two left-handed helices. The maximum field will be limited to 4 Tesla. While small bore helical undulators have been built for free electron lasers, large super conducting helical magnets have not been built yet. In spite of this difficulty, this choice is dictated by some distinctive advantages of helical over more conventional transverse snakes/rotators: (i) the devices are modular, they can be built with arrangements of identical modules, (ii) the maximum orbit excursion in the magnet is smaller, (iii) orbit excursion is independent from the separation between adjacent magnets, (iv) they allow an easier control of the spin rotation and the orientation of the spin precession axis

  19. T violating neutron spin rotation asymmetry

    International Nuclear Information System (INIS)

    Masuda, Yasushiro.

    1993-01-01

    A new experiment on T-violation is proposed, where a spin-rotating-neutron transmission through a polarized nuclear target is measuered. The method to control the neutron spin is discussed for the new T-violation experiment. The present method has possibility to provide us more accurate T-violation information than the neutron EDM measurement

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

    International Nuclear Information System (INIS)

    Mueller, K.T.; California Univ., Berkeley, CA

    1991-07-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1991-07-01

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

  2. Spin rotation function in a microscopic non-relativistic optical model

    International Nuclear Information System (INIS)

    Bauhoff, W.

    1984-01-01

    A microscopic optical potential, which is calculated non-relativistically with a density-dependent effective force, is used to calculate cross-section, polarization and spin-rotation function for elastic proton scattering from 40 Ca at 160 MeV and 497 MeV. At 160 MeV, the agreement to the data is comparable to phenomenological fits, and the spin-rotation can be used to distinguish between microscopic and Woods-Saxon potentials. A good fit to the spin-rotation function results at 497 MeV, whereas the polarization data are not well reproduced

  3. Rotatable spin-polarized electron source for inverse-photoemission experiments

    International Nuclear Information System (INIS)

    Stolwijk, S. D.; Wortelen, H.; Schmidt, A. B.; Donath, M.

    2014-01-01

    We present a ROtatable Spin-polarized Electron source (ROSE) for the use in spin- and angle-resolved inverse-photoemission (SR-IPE) experiments. A key feature of the ROSE is a variable direction of the transversal electron beam polarization. As a result, the inverse-photoemission experiment becomes sensitive to two orthogonal in-plane polarization directions, and, for nonnormal electron incidence, to the out-of-plane polarization component. We characterize the ROSE and test its performance on the basis of SR-IPE experiments. Measurements on magnetized Ni films on W(110) serve as a reference to demonstrate the variable spin sensitivity. Moreover, investigations of the unoccupied spin-dependent surface electronic structure of Tl/Si(111) highlight the capability to analyze complex phenomena like spin rotations in momentum space. Essentially, the ROSE opens the way to further studies on complex spin-dependent effects in the field of surface magnetism and spin-orbit interaction at surfaces

  4. Magnetization rotation or generation of incoherent spin waves? Suggestions for a spin-transfer effect experiment

    International Nuclear Information System (INIS)

    Bazaliy, Y. B.; Jones, B. A.

    2002-01-01

    ''Spin-transfer'' torque is created when electric current is passed through metallic ferromagnets and may have interesting applications in spintronics. So far it was experimentally studied in ''collinear'' geometries, where it is difficult to predict whether magnetization will coherently rotate or spin-waves will be generated. Here we propose an easy modification of existing experiment in which the spin-polarization of incoming current will no longer be collinear with magnetization and recalculate the switching behavior of the device. We expect that a better agreement with the magnetization rotation theory will be achieved. That can be an important step in reconciling alternative points of view on the effect of spin-transfer torque

  5. Phase-shift and spin-rotation phenomena in neutron interferometry

    International Nuclear Information System (INIS)

    Badurek, G.; Rauch, H.; Zeilinger, A.; Bauspiess, W.; Bonse, U.

    1976-01-01

    The perfect-crystal neutron interferometer was used to study characteristic phenomena arising from simultaneous phase shift and spin rotation of neutron waves. In accordance with theoretical predictions, the beams leaving the interferometer became partially polarized, even with unpolarized incident neutrons. The intensity and the polarization as a function of phase shift and spin rotation have been found to oscillate with the same period, displaying a mutual beat pattern

  6. Torsionally mediated spin-rotation hyperfine splittings at moderate to high J values in methanol

    Science.gov (United States)

    Belov, S. P.; Golubiatnikov, G. Yu.; Lapinov, A. V.; Ilyushin, V. V.; Alekseev, E. A.; Mescheryakov, A. A.; Hougen, J. T.; Xu, Li-Hong

    2016-07-01

    This paper presents an explanation based on torsionally mediated proton-spin-overall-rotation interaction for the observation of doublet hyperfine splittings in some Lamb-dip sub-millimeter-wave transitions between ground-state torsion-rotation states of E symmetry in methanol. These unexpected doublet splittings, some as large as 70 kHz, were observed for rotational quantum numbers in the range of J = 13 to 34, and K = - 2 to +3. Because they increase nearly linearly with J for a given branch, we confined our search for an explanation to hyperfine operators containing one nuclear-spin angular momentum factor I and one overall-rotation angular momentum factor J (i.e., to spin-rotation operators) and ignored both spin-spin and spin-torsion operators, since they contain no rotational angular momentum operator. Furthermore, since traditional spin-rotation operators did not seem capable of explaining the observed splittings, we constructed totally symmetric "torsionally mediated spin-rotation operators" by multiplying the E-species spin-rotation operator by an E-species torsional-coordinate factor of the form e±niα. The resulting operator is capable of connecting the two components of a degenerate torsion-rotation E state. This has the effect of turning the hyperfine splitting pattern upside down for some nuclear-spin states, which leads to bottom-to-top and top-to-bottom hyperfine selection rules for some transitions, and thus to an explanation for the unexpectedly large observed hyperfine splittings. The constructed operator cannot contribute to hyperfine splittings in the A-species manifold because its matrix elements within the set of torsion-rotation A1 and A2 states are all zero. The theory developed here fits the observed large doublet splittings to a root-mean-square residual of less than 1 kHz and predicts unresolvable splittings for a number of transitions in which no doublet splitting was detected.

  7. Magnetic field devices for neutron spin transport and manipulation in precise neutron spin rotation measurements

    Energy Technology Data Exchange (ETDEWEB)

    Maldonado-Velázquez, M. [Posgrado en Ciencias Físicas, Universidad Nacional Autónoma de México, 04510 (Mexico); Barrón-Palos, L., E-mail: libertad@fisica.unam.mx [Instituto de Física, Universidad Nacional Autónoma de México, Apartado Postal 20-364, 01000 (Mexico); Crawford, C. [University of Kentucky, Lexington, KY 40506 (United States); Snow, W.M. [Indiana University, Bloomington, IN 47405 (United States)

    2017-05-11

    The neutron spin is a critical degree of freedom for many precision measurements using low-energy neutrons. Fundamental symmetries and interactions can be studied using polarized neutrons. Parity-violation (PV) in the hadronic weak interaction and the search for exotic forces that depend on the relative spin and velocity, are two questions of fundamental physics that can be studied via the neutron spin rotations that arise from the interaction of polarized cold neutrons and unpolarized matter. The Neutron Spin Rotation (NSR) collaboration developed a neutron polarimeter, capable of determining neutron spin rotations of the order of 10{sup −7} rad per meter of traversed material. This paper describes two key components of the NSR apparatus, responsible for the transport and manipulation of the spin of the neutrons before and after the target region, which is surrounded by magnetic shielding and where residual magnetic fields need to be below 100 μG. These magnetic field devices, called input and output coils, provide the magnetic field for adiabatic transport of the neutron spin in the regions outside the magnetic shielding while producing a sharp nonadiabatic transition of the neutron spin when entering/exiting the low-magnetic-field region. In addition, the coils are self contained, forcing the return magnetic flux into a compact region of space to minimize fringe fields outside. The design of the input and output coils is based on the magnetic scalar potential method.

  8. Spin-rotation and NMR shielding constants in HCl

    Energy Technology Data Exchange (ETDEWEB)

    Jaszuński, Michał, E-mail: michal.jaszunski@icho.edu.pl [Institute of Organic Chemistry, Polish Academy of Sciences, 01-224 Warszawa, Kasprzaka 44 (Poland); Repisky, Michal; Demissie, Taye B.; Komorovsky, Stanislav; Malkin, Elena; Ruud, Kenneth [Centre for Theoretical and Computational Chemistry, University of Tromsø—The Arctic University of Norway, N-9037 Tromsø (Norway); Garbacz, Piotr; Jackowski, Karol; Makulski, Włodzimierz [Laboratory of NMR Spectroscopy, Department of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw (Poland)

    2013-12-21

    The spin-rotation and nuclear magnetic shielding constants are analysed for both nuclei in the HCl molecule. Nonrelativistic ab initio calculations at the CCSD(T) level of approximation show that it is essential to include relativistic effects to obtain spin-rotation constants consistent with accurate experimental data. Our best estimates for the spin-rotation constants of {sup 1}H{sup 35}Cl are C{sub Cl}  = −53.914 kHz and C{sub H}  = 42.672 kHz (for the lowest rovibrational level). For the chlorine shielding constant, the ab initio value computed including the relativistic corrections, σ(Cl) = 976.202 ppm, provides a new absolute shielding scale; for hydrogen we find σ(H) = 31.403 ppm (both at 300 K). Combining the theoretical results with our new gas-phase NMR experimental data allows us to improve the accuracy of the magnetic dipole moments of both chlorine isotopes. For the hydrogen shielding constant, including relativistic effects yields better agreement between experimental and computed values.

  9. Spin-rotation and NMR shielding constants in HCl

    International Nuclear Information System (INIS)

    Jaszuński, Michał; Repisky, Michal; Demissie, Taye B.; Komorovsky, Stanislav; Malkin, Elena; Ruud, Kenneth; Garbacz, Piotr; Jackowski, Karol; Makulski, Włodzimierz

    2013-01-01

    The spin-rotation and nuclear magnetic shielding constants are analysed for both nuclei in the HCl molecule. Nonrelativistic ab initio calculations at the CCSD(T) level of approximation show that it is essential to include relativistic effects to obtain spin-rotation constants consistent with accurate experimental data. Our best estimates for the spin-rotation constants of 1 H 35 Cl are C Cl   = −53.914 kHz and C H   = 42.672 kHz (for the lowest rovibrational level). For the chlorine shielding constant, the ab initio value computed including the relativistic corrections, σ(Cl) = 976.202 ppm, provides a new absolute shielding scale; for hydrogen we find σ(H) = 31.403 ppm (both at 300 K). Combining the theoretical results with our new gas-phase NMR experimental data allows us to improve the accuracy of the magnetic dipole moments of both chlorine isotopes. For the hydrogen shielding constant, including relativistic effects yields better agreement between experimental and computed values

  10. Experimental verification of the rotational type of chiral spin spiral structures by spin-polarized scanning tunneling microscopy.

    Science.gov (United States)

    Haze, Masahiro; Yoshida, Yasuo; Hasegawa, Yukio

    2017-10-16

    We report on experimental verification of the rotational type of chiral spin spirals in Mn thin films on a W(110) substrate using spin-polarized scanning tunneling microscopy (SP-STM) with a double-axis superconducting vector magnet. From SP-STM images using Fe-coated W tips magnetized to the out-of-plane and [001] directions, we found that both Mn mono- and double-layers exhibit cycloidal rotation whose spins rotate in the planes normal to the propagating directions. Our results agree with the theoretical prediction based on the symmetry of the system, supporting that the magnetic structures are driven by the interfacial Dzyaloshinskii-Moriya interaction.

  11. Efficient calculation of nuclear spin-rotation constants from auxiliary density functional theory

    International Nuclear Information System (INIS)

    Zuniga-Gutierrez, Bernardo; Camacho-Gonzalez, Monica; Bendana-Castillo, Alfonso; Simon-Bastida, Patricia; Calaminici, Patrizia; Köster, Andreas M.

    2015-01-01

    The computation of the spin-rotation tensor within the framework of auxiliary density functional theory (ADFT) in combination with the gauge including atomic orbital (GIAO) scheme, to treat the gauge origin problem, is presented. For the spin-rotation tensor, the calculation of the magnetic shielding tensor represents the most demanding computational task. Employing the ADFT-GIAO methodology, the central processing unit time for the magnetic shielding tensor calculation can be dramatically reduced. In this work, the quality of spin-rotation constants obtained with the ADFT-GIAO methodology is compared with available experimental data as well as with other theoretical results at the Hartree-Fock and coupled-cluster level of theory. It is found that the agreement between the ADFT-GIAO results and the experiment is good and very similar to the ones obtained by the coupled-cluster single-doubles-perturbative triples-GIAO methodology. With the improved computational performance achieved, the computation of the spin-rotation tensors of large systems or along Born-Oppenheimer molecular dynamics trajectories becomes feasible in reasonable times. Three models of carbon fullerenes containing hundreds of atoms and thousands of basis functions are used for benchmarking the performance. Furthermore, a theoretical study of temperature effects on the structure and spin-rotation tensor of the H 12 C– 12 CH–DF complex is presented. Here, the temperature dependency of the spin-rotation tensor of the fluorine nucleus can be used to identify experimentally the so far unknown bent isomer of this complex. To the best of our knowledge this is the first time that temperature effects on the spin-rotation tensor are investigated

  12. Efficient calculation of nuclear spin-rotation constants from auxiliary density functional theory

    Energy Technology Data Exchange (ETDEWEB)

    Zuniga-Gutierrez, Bernardo, E-mail: bzuniga.51@gmail.com [Departamento de Ciencias Computacionales, Universidad de Guadalajara, Blvd. Marcelino García Barragán 1421, C.P. 44430 Guadalajara, Jalisco (Mexico); Camacho-Gonzalez, Monica [Universidad Tecnológica de Tecámac, División A2, Procesos Industriales, Carretera Federal México Pachuca Km 37.5, Col. Sierra Hermosa, C.P. 55740 Tecámac, Estado de México (Mexico); Bendana-Castillo, Alfonso [Universidad Tecnológica de Tecámac, División A3, Tecnologías de la Información y Comunicaciones, Carretera Federal México Pachuca Km 37.5, Col. Sierra Hermosa, C.P. 55740 Tecámac, Estado de México (Mexico); Simon-Bastida, Patricia [Universidad Tecnlógica de Tulancingo, División Electromecánica, Camino a Ahuehuetitla No. 301, Col. Las Presas, C.P. 43642 Tulancingo, Hidalgo (Mexico); Calaminici, Patrizia; Köster, Andreas M. [Departamento de Química, CINVESTAV, Avenida Instituto Politécnico Nacional 2508, A.P. 14-740, México D.F. 07000 (Mexico)

    2015-09-14

    The computation of the spin-rotation tensor within the framework of auxiliary density functional theory (ADFT) in combination with the gauge including atomic orbital (GIAO) scheme, to treat the gauge origin problem, is presented. For the spin-rotation tensor, the calculation of the magnetic shielding tensor represents the most demanding computational task. Employing the ADFT-GIAO methodology, the central processing unit time for the magnetic shielding tensor calculation can be dramatically reduced. In this work, the quality of spin-rotation constants obtained with the ADFT-GIAO methodology is compared with available experimental data as well as with other theoretical results at the Hartree-Fock and coupled-cluster level of theory. It is found that the agreement between the ADFT-GIAO results and the experiment is good and very similar to the ones obtained by the coupled-cluster single-doubles-perturbative triples-GIAO methodology. With the improved computational performance achieved, the computation of the spin-rotation tensors of large systems or along Born-Oppenheimer molecular dynamics trajectories becomes feasible in reasonable times. Three models of carbon fullerenes containing hundreds of atoms and thousands of basis functions are used for benchmarking the performance. Furthermore, a theoretical study of temperature effects on the structure and spin-rotation tensor of the H{sup 12}C–{sup 12}CH–DF complex is presented. Here, the temperature dependency of the spin-rotation tensor of the fluorine nucleus can be used to identify experimentally the so far unknown bent isomer of this complex. To the best of our knowledge this is the first time that temperature effects on the spin-rotation tensor are investigated.

  13. Efficient calculation of nuclear spin-rotation constants from auxiliary density functional theory.

    Science.gov (United States)

    Zuniga-Gutierrez, Bernardo; Camacho-Gonzalez, Monica; Bendana-Castillo, Alfonso; Simon-Bastida, Patricia; Calaminici, Patrizia; Köster, Andreas M

    2015-09-14

    The computation of the spin-rotation tensor within the framework of auxiliary density functional theory (ADFT) in combination with the gauge including atomic orbital (GIAO) scheme, to treat the gauge origin problem, is presented. For the spin-rotation tensor, the calculation of the magnetic shielding tensor represents the most demanding computational task. Employing the ADFT-GIAO methodology, the central processing unit time for the magnetic shielding tensor calculation can be dramatically reduced. In this work, the quality of spin-rotation constants obtained with the ADFT-GIAO methodology is compared with available experimental data as well as with other theoretical results at the Hartree-Fock and coupled-cluster level of theory. It is found that the agreement between the ADFT-GIAO results and the experiment is good and very similar to the ones obtained by the coupled-cluster single-doubles-perturbative triples-GIAO methodology. With the improved computational performance achieved, the computation of the spin-rotation tensors of large systems or along Born-Oppenheimer molecular dynamics trajectories becomes feasible in reasonable times. Three models of carbon fullerenes containing hundreds of atoms and thousands of basis functions are used for benchmarking the performance. Furthermore, a theoretical study of temperature effects on the structure and spin-rotation tensor of the H(12)C-(12)CH-DF complex is presented. Here, the temperature dependency of the spin-rotation tensor of the fluorine nucleus can be used to identify experimentally the so far unknown bent isomer of this complex. To the best of our knowledge this is the first time that temperature effects on the spin-rotation tensor are investigated.

  14. Spin rotation after a spin-independent scattering. Spin properties of an electron gas in a solid

    International Nuclear Information System (INIS)

    Zayets, V.

    2014-01-01

    It is shown that spin direction of an electron may not be conserved after a spin-independent scattering. The spin rotations occur due to a quantum-mechanical fact that when a quantum state is occupied by two electrons of opposite spins, the total spin of the state is zero and the spin direction of each electron cannot be determined. It is shown that it is possible to divide all conduction electrons into two group distinguished by their time-reversal symmetry. In the first group the electron spins are all directed in one direction. In the second group there are electrons of all spin directions. The number of electrons in each group is conserved after a spin-independent scattering. This makes it convenient to use these groups for the description of the magnetic properties of conduction electrons. The energy distribution of spins, the Pauli paramagnetism and the spin distribution in the ferromagnetic metals are described within the presented model. The effects of spin torque and spin-torque current are described. The origin of spin-transfer torque is explained within the presented model

  15. Quantum spin liquids in the absence of spin-rotation symmetry: Application to herbertsmithite

    Science.gov (United States)

    Dodds, Tyler; Bhattacharjee, Subhro; Kim, Yong Baek

    2013-12-01

    It has been suggested that the nearest-neighbor antiferromagnetic Heisenberg model on the Kagome lattice may be a good starting point for understanding the spin-liquid behavior discovered in herbertsmithite. In this work, we investigate possible quantum spin liquid phases in the presence of spin-rotation symmetry-breaking perturbations such as Dzyaloshinskii-Moriya and Ising interactions, as well as second-neighbor antiferromagnetic Heisenberg interactions. Experiments suggest that such perturbations are likely to be present in herbertsmithite. We use the projective symmetry group analysis within the framework of the slave-fermion construction of quantum spin liquid phases and systematically classify possible spin liquid phases in the presence of perturbations mentioned above. The dynamical spin-structure factor for relevant spin liquid phases is computed and the effect of those perturbations are studied. Our calculations reveal dispersive features in the spin structure factor embedded in a generally diffuse background due to the existence of fractionalized spin-1/2 excitations called spinons. For two of the previously proposed Z2 states, the dispersive features are almost absent, and diffuse scattering dominates over a large energy window throughout the Brillouin zone. This resembles the structure factor observed in recent inelastic neutron-scattering experiments on singlet crystals of herbertsmithite. Furthermore, one of the Z2 states with the spin structure factor with mostly diffuse scattering is gapped, and it may be adiabatically connected to the gapped spin liquid state observed in recent density-matrix renormalization group calculations for the nearest-neighbor antiferromagnetic Heisenberg model. The perturbations mentioned above are found to enhance the diffuse nature of the spin structure factor and reduce the momentum dependencies of the spin gap. We also calculate the electron spin resonance (ESR) absorption spectra that further characterize the role of

  16. Torsionally mediated spin-rotation hyperfine splittings at moderate to high J values in methanol

    Energy Technology Data Exchange (ETDEWEB)

    Belov, S. P.; Golubiatnikov, G. Yu.; Lapinov, A. V. [Institute of Applied Physics of the Russian Academy of Sciences, 46 Ulyanov Street, 603950 Nizhny Novgorod (Russian Federation); Ilyushin, V. V.; Mescheryakov, A. A. [Institute of Radio Astronomy of National Academy of Sciences of Ukraine, Chervonopraporna 4, 61002 Kharkov (Ukraine); Alekseev, E. A. [Institute of Radio Astronomy of National Academy of Sciences of Ukraine, Chervonopraporna 4, 61002 Kharkov (Ukraine); Quantum Radiophysics Department of V. N. Karazin Kharkiv National University, Svobody Square 4, 61022 Kharkov (Ukraine); Hougen, J. T., E-mail: jon.hougen@nist.gov [Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8441 (United States); Xu, Li-Hong [Department of Physics and Centre for Laser, Atomic, and Molecular Sciences, University of New Brunswick, Saint John, New Brunswick E2L 4L5 (Canada)

    2016-07-14

    This paper presents an explanation based on torsionally mediated proton-spin–overall-rotation interaction for the observation of doublet hyperfine splittings in some Lamb-dip sub-millimeter-wave transitions between ground-state torsion-rotation states of E symmetry in methanol. These unexpected doublet splittings, some as large as 70 kHz, were observed for rotational quantum numbers in the range of J = 13 to 34, and K = − 2 to +3. Because they increase nearly linearly with J for a given branch, we confined our search for an explanation to hyperfine operators containing one nuclear-spin angular momentum factor I and one overall-rotation angular momentum factor J (i.e., to spin-rotation operators) and ignored both spin-spin and spin-torsion operators, since they contain no rotational angular momentum operator. Furthermore, since traditional spin-rotation operators did not seem capable of explaining the observed splittings, we constructed totally symmetric “torsionally mediated spin-rotation operators” by multiplying the E-species spin-rotation operator by an E-species torsional-coordinate factor of the form e{sup ±niα}. The resulting operator is capable of connecting the two components of a degenerate torsion-rotation E state. This has the effect of turning the hyperfine splitting pattern upside down for some nuclear-spin states, which leads to bottom-to-top and top-to-bottom hyperfine selection rules for some transitions, and thus to an explanation for the unexpectedly large observed hyperfine splittings. The constructed operator cannot contribute to hyperfine splittings in the A-species manifold because its matrix elements within the set of torsion-rotation A{sub 1} and A{sub 2} states are all zero. The theory developed here fits the observed large doublet splittings to a root-mean-square residual of less than 1 kHz and predicts unresolvable splittings for a number of transitions in which no doublet splitting was detected.

  17. Quantum measurement of a rapidly rotating spin qubit in diamond.

    Science.gov (United States)

    Wood, Alexander A; Lilette, Emmanuel; Fein, Yaakov Y; Tomek, Nikolas; McGuinness, Liam P; Hollenberg, Lloyd C L; Scholten, Robert E; Martin, Andy M

    2018-05-01

    A controlled qubit in a rotating frame opens new opportunities to probe fundamental quantum physics, such as geometric phases in physically rotating frames, and can potentially enhance detection of magnetic fields. Realizing a single qubit that can be measured and controlled during physical rotation is experimentally challenging. We demonstrate quantum control of a single nitrogen-vacancy (NV) center within a diamond rotated at 200,000 rpm, a rotational period comparable to the NV spin coherence time T 2 . We stroboscopically image individual NV centers that execute rapid circular motion in addition to rotation and demonstrate preparation, control, and readout of the qubit quantum state with lasers and microwaves. Using spin-echo interferometry of the rotating qubit, we are able to detect modulation of the NV Zeeman shift arising from the rotating NV axis and an external DC magnetic field. Our work establishes single NV qubits in diamond as quantum sensors in the physically rotating frame and paves the way for the realization of single-qubit diamond-based rotation sensors.

  18. Spin-orbit-coupled Bose-Einstein condensates of rotating polar molecules

    Science.gov (United States)

    Deng, Y.; You, L.; Yi, S.

    2018-05-01

    An experimental proposal for realizing spin-orbit (SO) coupling of pseudospin 1 in the ground manifold 1Σ (υ =0 ) of (bosonic) bialkali polar molecules is presented. The three spin components are composed of the ground rotational state and two substates from the first excited rotational level. Using hyperfine resolved Raman processes through two select excited states resonantly coupled by a microwave, an effective coupling between the spin tensor and linear momentum is realized. The properties of Bose-Einstein condensates for such SO-coupled molecules exhibiting dipolar interactions are further explored. In addition to the SO-coupling-induced stripe structures, the singly and doubly quantized vortex phases are found to appear, implicating exciting opportunities for exploring novel quantum physics using SO-coupled rotating polar molecules with dipolar interactions.

  19. Non-exponential decoherence of radio-frequency resonance rotation of spin in storage rings

    Science.gov (United States)

    Saleev, A.; Nikolaev, N. N.; Rathmann, F.; Hinder, F.; Pretz, J.; Rosenthal, M.

    2017-08-01

    Precision experiments, such as the search for electric dipole moments of charged particles using radio-frequency spin rotators in storage rings, demand for maintaining the exact spin resonance condition for several thousand seconds. Synchrotron oscillations in the stored beam modulate the spin tune of off-central particles, moving it off the perfect resonance condition set for central particles on the reference orbit. Here, we report an analytic description of how synchrotron oscillations lead to non-exponential decoherence of the radio-frequency resonance driven up-down spin rotations. This non-exponential decoherence is shown to be accompanied by a nontrivial walk of the spin phase. We also comment on sensitivity of the decoherence rate to the harmonics of the radio-frequency spin rotator and a possibility to check predictions of decoherence-free magic energies.

  20. Exploring the dynamics about the glass transition by muon spin relaxation and muon spin rotation

    International Nuclear Information System (INIS)

    Bermejo, F J; Bustinduy, I; Cox, S F J; Lord, J S; Cabrillo, C; Gonzalez, M A

    2006-01-01

    The capability of muon spin rotation and muon spin relaxation to explore dynamics in the vicinity of the glass transition is illustrated by results pertaining to three materials exhibiting two different glass-forming abilities. Measurements under transverse magnetic fields enable us to monitor the dynamics of muonium-labelled closed-shell molecules within the microsecond range. The results display the onset of stochastic molecular motions taking place upon crossing from below the glass-transition temperature. In turn, the molecular dynamics of radicals formed by addition of atomic muonium to unsaturated organic molecules can also be explored up to far shorter times by means of relaxation measurements under longitudinal fields. The technique is then shown to be capable of singling out stochastic reorientational motions from others, which usually are strongly coupled to them and usually dominate the material response when measured using higher-frequency probes such as neutron and light scattering

  1. Rotational and spin viscosities of water: Application to nanofluidics

    DEFF Research Database (Denmark)

    Hansen, Jesper Søndergaard; Bruus, Henrik; Todd, B.D.

    2010-01-01

    In this paper we evaluate the rotational viscosity and the two spin viscosities for liquid water using equilibrium molecular dynamics. Water is modeled via the flexible SPC/Fw model where the Coulomb interactions are calculated via the Wolf method which enables the long simulation times required....... We find that the rotational viscosity is independent of the temperature in the range from 284 to 319 K. The two spin viscosities, on the other hand, decrease with increasing temperature and are found to be two orders of magnitude larger than that estimated by Bonthuis et al. [Phys. Rev. Lett. 103...

  2. Spin imaging in solids using synchronously rotating field gradients and samples

    International Nuclear Information System (INIS)

    Wind, R.A.; Yannoni, C.S.

    1983-01-01

    A method for spin-imaging in solids using nuclear magnetic resonance (NMR) spectroscopy is described. With this method, the spin density distribution of a two- or three-dimensional object such as a solid can be constructed resulting in an image of the sample. This method lends itself to computer control to map out an image of the object. This spin-imaging method involves the steps of placing a solid sample in the rf coil field and the external magnetic field of an NMR spectrometer. A magnetic field gradient is superimposed across the sample to provide a field gradient which results in a varying DC field that has different values over different parts of the sample. As a result, nuclei in different parts of the sample have different resonant NMR frequencies. The sample is rotated about an axis which makes a particular angle of 54.7 degrees with the static external magnetic field. The magnetic field gradient which has a spatial distribution related to the sample spinning axis is then rotated synchronously with the sample. Data is then collected while performing a solid state NMR line narrowing procedure. The next step is to change the phase relation between the sample rotation and the field gradient rotation. The data is again collected as before while the sample and field gradient are synchronously rotated. The phase relation is changed a number of times and data collected each time. The spin image of the solid sample is then reconstructed from the collected data

  3. Spin in stationary gravitational fields and rotating frames

    International Nuclear Information System (INIS)

    Obukhov, Yuri N.; Silenko, Alexander J.; Teryaev, Oleg V.

    2010-01-01

    A spin motion of particles in stationary spacetimes is investigated in the framework of the classical gravity and relativistic quantum mechanics. We bring the Dirac equation for relativistic particles in nonstatic spacetimes to the Hamiltonian form and perform the Foldy-Wouthuysen transformation. We show the importance of the choice of tetrads for description of spin dynamics in the classical gravity. We derive classical and quantum mechanical equations of motion of the spin for relativistic particles in stationary gravitational fields and rotating frames and establish the full agreement between the classical and quantum mechanical approaches.

  4. Muon spin-rotation study on magnetite

    International Nuclear Information System (INIS)

    Boekema, C.; Brabers, V.A.M.; Denison, A.B.; Heffner, R.H.; Hutson, R.L.; Leon, M.; Olsen, C.E.; Schillaci, M.E.

    1982-01-01

    Muon spin-rotation (μSR) results on synthetic single crystals of magnetite (Fe 3 O 4 ) support the idea of muon bond formation in oxides. The anomaly in the temperature dependence of the μSR signal observed in Fe 3 O 4 may be attributed to the existence of molecular polarons in the Verwey transition-temperature region

  5. Spin Tunneling in a Rotating Nanomagnet

    Science.gov (United States)

    O'Keeffe, Michael; Chudnovsky, Eugene; Lehman College Theoretical Condensed Matter Physics Team

    2011-03-01

    We study spin tunneling in a magnetic nanoparticle with biaxial anisotropy that is free to rotate about its anisotropy axis. Exact instanton of the coupled equations of motion is found that connects degenerate classical energy minima. We show that mechanical freedom of the particle renormalizes magnetic anisotropy and increases the tunnel splitting. M. F. O'Keeffe and E. M. Chudnovsky, cond-mat, arXiv:1011.3134.

  6. Beyond RPA in nuclear rotation and wobbling motion at high spin

    International Nuclear Information System (INIS)

    Kaneko, Kazunari

    1991-01-01

    A quantum mechanical method of the nuclear rotation and the wobbling motion at high spin beyond the small-oscillation approximation is represented within the framework of time-dependent mean-field theory with some constraints. The constraints which determine the choice of the rotating reference frame are considered in the spin-orientation frame and the principal-axis frame. The quantization under such constraints is performed by making use of the Dirac bracket. Then the commutation relations of the angular momentum are derived. (orig.)

  7. Predicting superdeformed rotational band-head spin in A ∼ 190 mass region using variable moment of inertia model

    International Nuclear Information System (INIS)

    Uma, V.S.; Goel, Alpana; Yadav, Archana; Jain, A.K.

    2016-01-01

    The band-head spin (I 0 ) of superdeformed (SD) rotational bands in A ∼ 190 mass region is predicted using the variable moment of inertia (VMI) model for 66 SD rotational bands. The superdeformed rotational bands exhibited considerably good rotational property and rigid behaviour. The transition energies were dependent on the prescribed band-head spins. The ratio of transition energies over spin Eγ/ 2 I (RTEOS) vs. angular momentum (I) have confirmed the rigid behaviour, provided the band-head spin value is assigned correctly. There is a good agreement between the calculated and the observed transition energies. This method gives a very comprehensive interpretation for spin assignment of SD rotational bands which could help in designing future experiments for SD bands. (author)

  8. Spin dependence of rotational damping by the rotational plane mapping method

    Energy Technology Data Exchange (ETDEWEB)

    Leoni, S; Bracco, A; Million, B [Milan Univ. (Italy). Ist. di Fisica; Herskind, B; Dossing, T; Rasmussen, P [Niels Bohr Inst., Copenhagen (Denmark); Bergstrom, M; Brockstedt, A; Carlsson, H; Ekstrom, P; Nordlund, A; Ryde, H [Lund Univ. (Sweden). Dept. of Physics; Ingebretsen, F; Tjom, P O [Oslo Univ. (Norway); Lonnroth, T [Aabo Akademi, Turku (Finland). Dept. of Physics

    1992-08-01

    In the study of deformed nuclei by gamma spectroscopy, the large quadrupole transition strength known from rotational bands at high excitation energy may be distributed over all final states of a given parity within an interval defined as the rotational damping width {Gamma}{sub rot} The method of rotational plane mapping extracts a value of {Gamma}{sub rot} from the width of valleys in certain planes in the grid plots of triple gamma coincidence data sets. The method was applied to a high spin triple data set on {sup 162,163}Tm taken with NORDBALL at the tandem accelerator of the Niels Bohr Institute, and formed in the reaction {sup 37}Cl + {sup 130}Te. The value {Gamma}{sub rot} = 85 keV was obtained. Generally, experimental values seem to be lower than theoretical predictions, although the only calculation made was for {sup 168}Yb. 6 refs., 3 figs.

  9. Rotational bands terminating at maximal spin in the valence space

    Energy Technology Data Exchange (ETDEWEB)

    Ragnarsson, I.; Afanasjev, A.V. [Lund Institute of Technology (Sweden)

    1996-12-31

    For nuclei with mass A {le} 120, the spin available in {open_quotes}normal deformation configurations{close_quotes} is experimentally accessible with present detector systems. Of special interest are the nuclei which show collective features at low or medium-high spin and where the corresponding rotational bands with increasing spin can be followed in a continuous way to or close to a non-collective terminating state. Some specific features in this context are discussed for nuclei in the A = 80 region and for {sup 117,118}Xe.

  10. Muon spin rotation measurements on LaNiSn

    International Nuclear Information System (INIS)

    Drew, A.J.; Lee, S.L.; Ogrin, F.Y.; Charalambous, D.; Bancroft, N.; Paul, D. McK.; Takabatake, T.; Baines, C.

    2006-01-01

    The first microscopic investigation of superconductivity in LaNiSn is reported using muon spin rotation. LaNiSn is found to be mainly a type I superconductor in an intermediate state with some evidence for type II behaviour at low temperatures, possibly due to a temperature dependent Ginzburg Landau parameter κ

  11. Gravitational waves from rotating neutron stars and evaluation of fast chirp transform techniques

    CERN Document Server

    Strohmayer, T E

    2002-01-01

    X-ray observations suggest that neutron stars in low mass x-ray binaries (LMXB) are rotating with frequencies in the range 300-600 Hz. These spin rates are significantly less than the break-up rates for essentially all realistic neutron star equations of state, suggesting that some process may limit the spin frequencies of accreting neutron stars to this range. If the accretion-induced spin up torque is in equilibrium with gravitational radiation losses, these objects could be interesting sources of gravitational waves. I present a brief summary of current measurements of neutron star spins in LMXBs based on the observations of high-Q oscillations during thermonuclear bursts (so-called 'burst oscillations'). Further measurements of neutron star spins will be important in exploring the gravitational radiation hypothesis in more detail. To this end, I also present a study of fast chirp transform (FCT) techniques as described by Jenet and Prince (Prince T A and Jenet F A 2000 Phys. Rev. D 62 122001) in the conte...

  12. High-spin rotational states in {sup 179}Os

    Energy Technology Data Exchange (ETDEWEB)

    Burde, J [Lawrence Berkeley Lab., CA (United States); [Hebrew Univ., Jerusalem (Israel). Racah Inst. of Physics; Deleplanque, M A; Diamond, R M; Macchiavelli, A O; Stephens, F S; Beausang, C W [Lawrence Berkeley Lab., CA (United States)

    1992-08-01

    The rotational bands of the osmium isotopes display very interesting properties that vary with the neutron number. On the one hand the yrast bands of {sup 182,184,186}Os display a sudden and rather strong gain in aligned angular momentum,, whereas the lighter osmium nuclei such as {sup 176,178,180}Os show a more gradual increase of alignment characteristic of strongly interacting bands. In addition, an unusual rotational band has been found in {sup 178}Os. It consists of seven regularly spaced transitions about 36 keV apart which correspond closely to the spacing of the superdeformed band in {sup 152}Dy after an A{sup 5/3} normalization. this band populates the yrast band directly, and the moment of inertia J{sup (1)} is found to be much smaller than J{sup (2)}. The most likely interpretation of this is a band with large deformation which is undergoing systematic changes in deformation, pairing and/or alignment. This latter finding in particular motivated us to carry out research on the higher spin states in {sup 179}Os. Dracoulis et al. have published their results on 5 rotational bands in {sup 179}Os. In the present work we found six new bands and extended appreciably the spin limits in the other five. (author). 5 refs., 3 figs.

  13. High-efficiency resonant rf spin rotator with broad phase space acceptance for pulsed polarized cold neutron beams

    Directory of Open Access Journals (Sweden)

    P.-N. Seo

    2008-08-01

    Full Text Available High precision fundamental neutron physics experiments have been proposed for the intense pulsed spallation neutron beams at JSNS, LANSCE, and SNS to test the standard model and search for new physics. Certain systematic effects in some of these experiments have to be controlled at the few ppb level. The NPDGamma experiment, a search for the small parity-violating γ-ray asymmetry A_{γ} in polarized cold neutron capture on parahydrogen, is one example. For the NPDGamma experiment we developed a radio-frequency resonant spin rotator to reverse the neutron polarization in a 9.5  cm×9.5  cm pulsed cold neutron beam with high efficiency over a broad cold neutron energy range. The effect of the spin reversal by the rotator on the neutron beam phase space is compared qualitatively to rf neutron spin flippers based on adiabatic fast passage. We discuss the design of the spin rotator and describe two types of transmission-based neutron spin-flip efficiency measurements where the neutron beam was both polarized and analyzed by optically polarized ^{3}He neutron spin filters. The efficiency of the spin rotator was measured at LANSCE to be 98.8±0.5% for neutron energies from 3 to 20 meV over the full phase space of the beam. Systematic effects that the rf spin rotator introduces to the NPDGamma experiment are considered.

  14. Rotating Wigner molecules and spin-related behaviors in quantum rings

    International Nuclear Information System (INIS)

    Yang Ning; Zhu Jialin; Dai Zhensheng

    2008-01-01

    The trial wavefunctions for few-electron quantum rings are presented to describe the spin-dependent rotating Wigner molecule states. The wavefunctions are constructed from the single-particle orbits which contain two variational parameters to describe the shape and size dependence of electron localization in the ring-like confinement. They can explicitly show the size dependence of single-particle orbital occupation to give an understanding of the spin rules of ground states without magnetic fields. They can also correctly describe the spin and angular momentum transitions in magnetic fields. By examining the von Neumann entropy, it is demonstrated that the wavefunctions can illustrate the entanglement between electrons in quantum rings, including the AB oscillations as well as the spin and size dependence of the entropy. Such trial wavefunctions will be useful in investigating spin-related quantum behaviors of a few electrons in quantum rings

  15. Sorting photons of different rotational Doppler shifts (RDS) by orbital angular momentum of single-photon with spin-orbit-RDS entanglement.

    Science.gov (United States)

    Chen, Lixiang; She, Weilong

    2008-09-15

    We demonstrate that single photons from a rotating q-plate exhibit an entanglement in three degrees of freedom of spin, orbital angular momentum, and the rotational Doppler shift (RDS) due to the nonconservation of total spin and orbital angular momenta. We find that the rotational Doppler shift deltaomega = Omega((delta)s + deltal) , where s, l and Omega are quantum numbers of spin, orbital angular momentum, and rotating velocity of the q-plate, respectively. Of interest is that the rotational Doppler shift directly reflects the rotational symmetry of q-plates and can be also expressed as deltaomega = (Omega)n , where n = 2(q-1) denotes the fold number of rotational symmetry. Besides, based on this single-photon spin-orbit-RDS entanglement, we propose an experimental scheme to sort photons of different frequency shifts according to individual orbital angular momentum.

  16. Relativistic theory of nuclear spin-rotation tensor with kinetically balanced rotational London orbitals

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Yunlong; Zhang, Yong; Liu, Wenjian, E-mail: liuwjbdf@gmail.com [Beijing National Laboratory for Molecular Sciences, Institute of Theoretical and Computational Chemistry, State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, and Center for Computational Science and Engineering, Peking University, Beijing 100871 (China)

    2014-10-28

    Both kinetically balanced (KB) and kinetically unbalanced (KU) rotational London orbitals (RLO) are proposed to resolve the slow basis set convergence in relativistic calculations of nuclear spin-rotation (NSR) coupling tensors of molecules containing heavy elements [Y. Xiao and W. Liu, J. Chem. Phys. 138, 134104 (2013)]. While they perform rather similarly, the KB-RLO Ansatz is clearly preferred as it ensures the correct nonrelativistic limit even with a finite basis. Moreover, it gives rise to the same “direct relativistic mapping” between nuclear magnetic resonance shielding and NSR coupling tensors as that without using the London orbitals [Y. Xiao, Y. Zhang, and W. Liu, J. Chem. Theory Comput. 10, 600 (2014)].

  17. Muon spin rotation studies of defect states in solids: the story of anomalous muonium

    International Nuclear Information System (INIS)

    Estle, T.L.

    1983-01-01

    Muon spin rotation (μSR) is a powerful technique to study magnetic phenomena, light interstitial diffusion, and hydrogenic chemistry. However it has been applied in several other areas of science where its applicability was not immediately apparent. One of these is the study of an unusual muonic defect, anomalous muonium, produced when μ + stops in semiconducting crystals. The study of anomalous muonium and the process of inferring its structure are described. For this defect, μSR has learned far more than have efforts to study the analogous hydrogenic center

  18. Demonstrating multibit magnetic memory in the Fe8 high-spin molecule by muon spin rotation

    Science.gov (United States)

    Shafir, Oren; Keren, Amit; Maegawa, Satoru; Ueda, Miki; Amato, Alex; Baines, Chris

    2005-09-01

    We develop a method to detect the quantum nature of high-spin molecules using muon spin rotation and a three-step field cycle ending always with the same field. We use this method to demonstrate that the Fe8 molecule can remember six (possibly eight) different histories (bits). A wide range of fields can be used to write a particular bit, and the information is stored in discrete states. Therefore, Fe8 can be used as a model compound for multibit magnetic memory. Our experiment also paves the way for magnetic quantum tunneling detection in films.

  19. Development of a 3He nuclear spin flip system on an in-situ SEOP 3He spin filter and demonstration for a neutron reflectometer and magnetic imaging technique

    International Nuclear Information System (INIS)

    Hayashida, H; Kira, H; Miyata, N; Akutsu, K; Mizusawa, M; Parker, J D; Matsumoto, Y; Oku, T; Sakai, K; Hiroi, K; Shinohara, T; Takeda, M; Yamazaki, D; Oikawa, K; Harada, M; Ino, T; Imagawa, T; Ohkawara, M; Ohoyama, K; Kakurai, K

    2016-01-01

    We have been developing a 3 He neutron spin filter (NSF) using the spin exchange optical pumping (SEOP) technique. The 3 He NSF provides a high-energy polarized neutron beam with large beam size. Moreover the 3 He NSF can work as a π-flipper for a polarized neutron beam by flipping the 3 He nuclear spin using a nuclear magnetic resonance (NMR) technique. For NMR with the in-situ SEOP technique, the polarization of the laser must be reversed simultaneously because a non-reversed laser reduces the polarization of the spin-flipped 3 He. To change the polarity of the laser, a half-wavelength plate was installed. The rotation angle of the half-wavelength plate was optimized, and a polarization of 97% was obtained for the circularly polarized laser. The 3 He polarization reached 70% and was stable over one week. A demonstration of the 3 He nuclear spin flip system was performed at the polarized neutron reflectometer SHARAKU (BL17) and NOBORU (BL10) at J-PARC. Off-specular measurement from a magnetic Fe/Cr thin film and magnetic imaging of a magnetic steel sheet were performed at BL17 and BL10, respectively. (paper)

  20. Demonstrating Multi-bit Magnetic Memory in the Fe8 High Spin Molecule by Muon Spin Rotation

    OpenAIRE

    Shafir, Oren; Keren, Amit; Maegawa, Satoru; Ueda, Miki; Amato, Alex; Baines, Chris

    2005-01-01

    We developed a method to detect the quantum nature of high spin molecules using muon spin rotation, and a three-step field cycle ending always with the same field. We use this method to demonstrate that the Fe8 molecule can remember 6 (possibly 8) different histories (bits). A wide range of fields can be used to write a particular bit, and the information is stored in discrete states. Therefore, Fe8 can be used as a model compound for Multi-bit Magnetic Memory. Our experiment also paves the w...

  1. Pulsar spin-down: the glitch-dominated rotation of PSR J0537-6910

    Science.gov (United States)

    Antonopoulou, D.; Espinoza, C. M.; Kuiper, L.; Andersson, N.

    2018-01-01

    The young, fast-spinning X-ray pulsar J0537-6910 displays an extreme glitch activity, with large spin-ups interrupting its decelerating rotation every ∼100 d. We present nearly 13 yr of timing data from this pulsar, obtained with the Rossi X-ray Timing Explorer. We discovered 22 new glitches and performed a consistent analysis of all 45 glitches detected in the complete data span. Our results corroborate the previously reported strong correlation between glitch spin-up size and the time to the next glitch, a relation that has not been observed so far in any other pulsar. The spin evolution is dominated by the glitches, which occur at a rate of ∼3.5 per year, and the post-glitch recoveries, which prevail the entire interglitch intervals. This distinctive behaviour provides invaluable insights into the physics of glitches. The observations can be explained with a multicomponent model that accounts for the dynamics of the neutron superfluid present in the crust and core of neutron stars. We place limits on the moment of inertia of the component responsible for the spin-up and, ignoring differential rotation, the velocity difference it can sustain with the crust. Contrary to its rapid decrease between glitches, the spin-down rate increased over the 13 yr, and we find the long-term braking index nl = -1.22(4), the only negative braking index seen in a young pulsar. We briefly discuss the plausible interpretations of this result, which is in stark contrast to the predictions of standard models of pulsar spin-down.

  2. Muon spin rotation studies of niobium for superconducting rf applications

    Directory of Open Access Journals (Sweden)

    A. Grassellino

    2013-06-01

    Full Text Available In this work we investigate superconducting properties of niobium samples via application of the muon spin rotation/relaxation (μSR technique. We employ for the first time the μSR technique to study samples that are cut out from large and small grain 1.5 GHz radio frequency (rf single cell niobium cavities. The rf test of these cavities was accompanied by full temperature mapping to characterize the rf losses in each of the samples. Results of the μSR measurements show that standard cavity surface treatments like mild baking and buffered chemical polishing performed on the studied samples affect their surface pinning strength. We find an interesting correlation between high field rf losses and field dependence of the sample magnetic volume fraction measured via μSR. The μSR line width observed in zero-field-μSR measurements matches the behavior of Nb samples doped with minute amounts of Ta or N impurities. A lower and an upper bound for the upper critical field H_{c2} of these cutouts is found.

  3. Rotational bands on few-particle excitations of very high spin

    International Nuclear Information System (INIS)

    Andersson, C.G.; Krumlinde, J.; Leander, G.; Szymanski, Z.

    1980-01-01

    An RPA formalism is developed to investigate the existence and properties of slow collective rotation around a non-symmetry axis, when there already exists a large angular momentum K along the symmetry axis built up by aligned single-particle spins. It is found necessary to distinguish between the collectivity and the repeatability of the rotational excitations. First the formalism is applied to bands on hihg-K isomers in the well-deformed nucleus 176 Hf, where the rotational-model picture is reproduced for intermediate K-values in agreement with experiment. At high K there is a suppression of the collectivity corresponding to the diminishing vector-coupling coefficient of the rotational model, but the repeatability actually improves. The moment of inertia is predicted to remain substantially smaller than the rigid-body value so the bands slope up steeply from the yrast line at spins where pairing effects are gone. A second application is to the initially spherical nucleus 212 Rn, which is believed to acquire an oblate deformation that increases steadily with K due to the oblate shape of the aligned orbitals. In this case the repeatable excitations come higher above the yrast line than in 176 Hf, even at comparable deformations. Some collective states may occur very close to yrast, but these are more like dressed singleparticle excitations. The main differences between the two nuclei studied is interpreted as a general consequence of their different shell structure. (author)

  4. Biologically aggressive regions within glioblastoma identified by spin-lock contrast T1 relaxation in the rotating frame (T1ρ MRI

    Directory of Open Access Journals (Sweden)

    Ramon Francisco Barajas, Jr., MD

    2017-12-01

    Full Text Available Spin-lattice relaxation in the rotating frame magnetic resonance imaging allows for the quantitative assessment of spin-lock contrast within tissues. We describe the utility of spin-lattice relaxation in the rotating frame metrics in characterizing glioblastoma biological heterogeneity. A 84-year-old man presented to our institution with a right frontal temporal mass. Prior tissue sampling from a peripheral nonenhancing lesion was nondiagnostic. Stereotactic image-guided tissue sampling of the nonenhancing T2-fluid-attenuated inversion recovery hyperintense region involving the anterior cingulate gyrus with elevated spin-lattice relaxation in the rotating frame metrics provided a pathologic diagnosis of glioblastoma. This case illustrates the utility of spin-lattice relaxation in the rotating frame magnetic resonance imaging in identifying biologically aggressive regions within glioblastoma.

  5. A low energy muon spin rotation and point contact tunneling study of niobium films prepared for superconducting cavities

    Science.gov (United States)

    Junginger, Tobias; Calatroni, S.; Sublet, A.; Terenziani, G.; Prokscha, T.; Salman, Z.; Suter, A.; Proslier, T.; Zasadzinski, J.

    2017-12-01

    Point contact tunneling and low energy muon spin rotation are used to probe, on the same samples, the surface superconducting properties of micrometer thick niobium films deposited onto copper substrates using different sputtering techniques: diode, dc magnetron and HIPIMS. The combined results are compared to radio-frequency tests performances of RF cavities made with the same processes. Degraded surface superconducting properties are found to correlate to lower quality factors and stronger Q-slope. In addition, both techniques find evidence for surface paramagnetism on all samples and particularly on Nb films prepared by HIPIMS.

  6. Optical rotation and electron spin resonance of an electro-optically active polythiophene

    International Nuclear Information System (INIS)

    Goto, Hiromasa

    2010-01-01

    Graphical abstract: The electro-chiroptical polythiophene displays optical rotation at wavelengths corresponding to the doping band observable in the absorption spectra. The formation of polarons on the main-chain is confirmed by electron spin resonance measurements. - Abstract: A chiroptical polythiophene, is synthesized by electrolytic polymerization in a cholesteric liquid crystal electrolyte solution. The polymer displays a fingerprint texture similar to that of the cholesteric electrolyte solution. Upon electrochemical doping, the polymer displays optical rotation at wavelengths corresponding to the doping band observable in the absorption spectra. The formation of polarons on the main-chain is confirmed by electron spin resonance measurements. The results demonstrate the intermolecular chirality of polarons in this π-conjugated polymer, indicating continuum delocalized polarons are in a three-dimensional helical environment.

  7. Strong coupling between a single nitrogen-vacancy spin and the rotational mode of diamonds levitating in an ion trap

    Science.gov (United States)

    Delord, T.; Nicolas, L.; Chassagneux, Y.; Hétet, G.

    2017-12-01

    A scheme for strong coupling between a single atomic spin and the rotational mode of levitating nanoparticles is proposed. The idea is based on spin readout of nitrogen-vacancy centers embedded in aspherical nanodiamonds levitating in an ion trap. We show that the asymmetry of the diamond induces a rotational confinement in the ion trap. Using a weak homogeneous magnetic field and a strong microwave driving we then demonstrate that the spin of the nitrogen-vacancy center can be strongly coupled to the rotational mode of the diamond.

  8. Output-only cyclo-stationary linear-parameter time-varying stochastic subspace identification method for rotating machinery and spinning structures

    Science.gov (United States)

    Velazquez, Antonio; Swartz, R. Andrew

    2015-02-01

    Economical maintenance and operation are critical issues for rotating machinery and spinning structures containing blade elements, especially large slender dynamic beams (e.g., wind turbines). Structural health monitoring systems represent promising instruments to assure reliability and good performance from the dynamics of the mechanical systems. However, such devices have not been completely perfected for spinning structures. These sensing technologies are typically informed by both mechanistic models coupled with data-driven identification techniques in the time and/or frequency domain. Frequency response functions are popular but are difficult to realize autonomously for structures of higher order, especially when overlapping frequency content is present. Instead, time-domain techniques have shown to possess powerful advantages from a practical point of view (i.e. low-order computational effort suitable for real-time or embedded algorithms) and also are more suitable to differentiate closely-related modes. Customarily, time-varying effects are often neglected or dismissed to simplify this analysis, but such cannot be the case for sinusoidally loaded structures containing spinning multi-bodies. A more complex scenario is constituted when dealing with both periodic mechanisms responsible for the vibration shaft of the rotor-blade system and the interaction of the supporting substructure. Transformations of the cyclic effects on the vibrational data can be applied to isolate inertial quantities that are different from rotation-generated forces that are typically non-stationary in nature. After applying these transformations, structural identification can be carried out by stationary techniques via data-correlated eigensystem realizations. In this paper, an exploration of a periodic stationary or cyclo-stationary subspace identification technique is presented here for spinning multi-blade systems by means of a modified Eigensystem Realization Algorithm (ERA) via

  9. The rotational mobility of spin labels in wool creatine depending on temperature, humidity and deformation

    International Nuclear Information System (INIS)

    Bobodzhanov, P.Kh.; Yusupov, I.Kh.; Marupov, R.

    2001-01-01

    Present article is devoted to study of rotational mobility of spin labels in wool creatine depending on temperature, humidity and deformation. The experimental data of study of structure and molecular mobility of wool creatine modified by spin labels was considered.

  10. Slotted rotatable target assembly and systematic error analysis for a search for long range spin dependent interactions from exotic vector boson exchange using neutron spin rotation

    Science.gov (United States)

    Haddock, C.; Crawford, B.; Fox, W.; Francis, I.; Holley, A.; Magers, S.; Sarsour, M.; Snow, W. M.; Vanderwerp, J.

    2018-03-01

    We discuss the design and construction of a novel target array of nonmagnetic test masses used in a neutron polarimetry measurement made in search for new possible exotic spin dependent neutron-atominteractions of Nature at sub-mm length scales. This target was designed to accept and efficiently transmit a transversely polarized slow neutron beam through a series of long open parallel slots bounded by flat rectangular plates. These openings possessed equal atom density gradients normal to the slots from the flat test masses with dimensions optimized to achieve maximum sensitivity to an exotic spin-dependent interaction from vector boson exchanges with ranges in the mm - μm regime. The parallel slots were oriented differently in four quadrants that can be rotated about the neutron beam axis in discrete 90°increments using a Geneva drive. The spin rotation signals from the 4 quadrants were measured using a segmented neutron ion chamber to suppress possible systematic errors from stray magnetic fields in the target region. We discuss the per-neutron sensitivity of the target to the exotic interaction, the design constraints, the potential sources of systematic errors which could be present in this design, and our estimate of the achievable sensitivity using this method.

  11. Spinning and rotating strings for N=1 SYM theory and brane constructions

    International Nuclear Information System (INIS)

    Schvellinger, Martin

    2004-01-01

    We obtain spinning and rotating closed string solutions in AdS 5 x T 1,1 background, and show how these solutions can be mapped onto rotating closed strings embedded in configurations of intersecting branes in type IIA string theory. Then, we discuss spinning closed string solutions in the UV limit of the Klebanov-Tseytlin background, and also properties of classical solutions in the related intersecting brane constructions in the UV limit. We comment on extensions of this analysis to the deformed conifold background, and in the corresponding intersecting brane construction, as well as its relation to the deep IR limit of the Klebanov-Strassler solution. We briefly discuss on the relation between type IIA brane constructions and their related M-theory descriptions, and how solitonic solutions are related in both descriptions. (author)

  12. Observability of the probability current density using spin rotator as a quantum clock

    International Nuclear Information System (INIS)

    Home, D.; Alok Kumar Pan; Md Manirul Ali

    2005-01-01

    Full text: An experimentally realizable scheme is formulated which can test any quantum mechanical approach for calculating the arrival time distribution. This is specifically illustrated by using the modulus of the probability current density for calculating the arrival time distribution of spin-1/2 neutral particles at the exit point of a spin rotator (SR) which contains a constant magnetic field. Such a calculated time distribution is then used for evaluating the distribution of spin orientations along different directions for these particles emerging from the SR. Based on this, the result of spin measurement along any arbitrary direction for such an ensemble is predicted. (author)

  13. Spin alignment and collective moment of inertia of the basic rotational band in the cranking model

    International Nuclear Information System (INIS)

    Tanaka, Yoshihide

    1982-01-01

    By making an attempt to separate the intrinsic particle and collective rotational motions in the cranking model, the spin alignment and the collective moment of inertia characterizing the basic rotational bands are defined, and are investigated by using a simple i sub(13/2) shell model. The result of the calculation indicates that the collective moment of inertia decreases under the presence of the quasiparticles which are responsible for the increase of the spin alignment of the band. (author)

  14. Four-Component Relativistic Density-Functional Theory Calculations of Nuclear Spin-Rotation Constants: Relativistic Effects in p-Block Hydrides.

    Science.gov (United States)

    Komorovsky, Stanislav; Repisky, Michal; Malkin, Elena; Demissie, Taye B; Ruud, Kenneth

    2015-08-11

    We present an implementation of the nuclear spin-rotation (SR) constants based on the relativistic four-component Dirac-Coulomb Hamiltonian. This formalism has been implemented in the framework of the Hartree-Fock and Kohn-Sham theory, allowing assessment of both pure and hybrid exchange-correlation functionals. In the density-functional theory (DFT) implementation of the response equations, a noncollinear generalized gradient approximation (GGA) has been used. The present approach enforces a restricted kinetic balance condition for the small-component basis at the integral level, leading to very efficient calculations of the property. We apply the methodology to study relativistic effects on the spin-rotation constants by performing calculations on XHn (n = 1-4) for all elements X in the p-block of the periodic table and comparing the effects of relativity on the nuclear SR tensors to that observed for the nuclear magnetic shielding tensors. Correlation effects as described by the density-functional theory are shown to be significant for the spin-rotation constants, whereas the differences between the use of GGA and hybrid density functionals are much smaller. Our calculated relativistic spin-rotation constants at the DFT level of theory are only in fair agreement with available experimental data. It is shown that the scaling of the relativistic effects for the spin-rotation constants (varying between Z(3.8) and Z(4.5)) is as strong as for the chemical shieldings but with a much smaller prefactor.

  15. Spin rotation in ErGa{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Murasik, A. E-mail: amur@cyf.gov.pl; Czopnik, A. E-mail: czopnik@int.pan.wroc.pl; Keller, L. E-mail: lukas.keller@psi.ch; Fischer, P. E-mail: peter.fischer@psi.ch

    2000-04-01

    The magnetic phase diagram of ErGa{sub 3}, built up from bulk magnetisation data, shows in zero-applied magnetic field two successive transitions at T{sub 1}=2.6 and T{sub 2} congruent with 2.8 K, respectively. The magnetic ordering of ErGa{sub 3} examined by neutron diffraction, can be derived from the so-called {l_brace}((1)/(2)), ((1)/(2)), 0{r_brace} structure, i.e. one in which the successive antiparallel (1 1 0) sheets of spins have additionally superimposed on them a sinusoidal modulation parallel to the [1 0 0] axis. The temperature dependence of neutron diffraction diagrams studied on the single crystal, revealed in the range of (2.6-2.78) K an abrupt reorientation of the Er{sup 3+} spins from the nearly [1 1 0] direction, towards the [1 0 0] axis. In this way previously observed effect on the polycrystalline sample has been confirmed. This rotation can be attributed to the T{sub 1} transition found in the H-T magnetic phase diagram.

  16. Search for right-handed currents by means of muon spin rotation

    International Nuclear Information System (INIS)

    Stoker, D.P.

    1985-01-01

    A muon spin rotation (μSR) technique has been used to place limits on right-handed weak currents in μ + decay. A beam of almost 100% polarized surface muons obtained from the TRIUMF M13 beamline was stopped in essentially non-depolarizing >99.99% pure metal foils. The μ + spins were precessed by 70-G or 110-G transverse fields. Decay e + emitted within 225 mrad of the beam direction and with momenta above 46 MeV/c were momentum-analyzed to 0.2%. Comparison of the μSR signal amplitude with that expected for (V-A) decay yields an endpoint asymmetry XiP/sub μ/δ/rho > 0.9951 with 90% confidence. In the context of manifest left-right symmetric models with massless neutrinos the results imply the 90% confidence limits M(W 2 ) > 381 GeV/c 2 and -0.057 2 is a predominantly right-handed gauge boson and zeta is the left-right mixing angle. Limits on M(W 2 ) for M(nu/sub μR/) does not equal 0 are also presented. The endpoint asymmetry is used to deduce limits on the nu/sub μL/ mass and helicity in π + decay, non-(V-A) couplings in helicity projection form, and the mass scale of composite leptons

  17. Search for right-handed currents by means of muon spin rotation

    International Nuclear Information System (INIS)

    Stoker, D.P.

    1985-09-01

    A muon spin rotation (μSR) technique has been used to place limits on right-handed weak currents in μ + decay. A beam of almost 100% polarized 'surface' muons obtained from the TRIUMF M13 beamline was stopped in essentially non-depolarizing >99.99% pure metal foils. The μ + spins were precessed by 70-G or 110-G transverse fields. Decay e + emitted within 225 mrad of the beam direction and with momenta above 46 MeV/c were momentum-analyzed to 0.2%. Comparison of the μSR signal amplitude with that expected for (V-A) decay yields an endpoint asymmetry xiPμdelta/rho>0.9951 with 90% confidence. In the context of manifest left-right symmetric models with massless neutrinos the results imply the 90% confidence limits M(W 2 )>381 GeV/c 2 and -0.057 2 is a predominantly right-handed gauge boson and zeta is the left-right mixing angle. Limits on M(W 2 ) for M(nu/sub μR) is not equal to 0 are also presented. The endpoint asymmetry is used to deduce limits on the nu/sub nu/sub μL/ mass and helicity in π + decay, non-(V-A) couplings in helicity projection form, and the mass scale of composite leptons

  18. Stationary states and rotational properties of spin-orbit-coupled Bose-Einstein condensates held under a toroidal trap

    Science.gov (United States)

    He, Zhang-Ming; Zhang, Xiao-Fei; Kato, Masaya; Han, Wei; Saito, Hiroki

    2018-06-01

    We consider a pseudospin-1/2 Bose-Einstein condensate with Rashba spin-orbit coupling in a two-dimensional toroidal trap. By solving the damped Gross-Pitaevskii equations for this system, we show that the system exhibits a rich variety of stationary states, such as vehicle wheel and flower-petal stripe patterns. These stationary states are stable against perturbation with thermal energy and can survive for a long time. In the presence of rotation, our results show that the rotating systems have exotic vortex configurations. These phenomenon originates from the interplay among spin-orbit coupling, trap geometry, and rotation.

  19. Protein rotational dynamics investigated with a dual EPR/optical molecular probe. Spin-labeled eosin.

    Science.gov (United States)

    Cobb, C E; Hustedt, E J; Beechem, J M; Beth, A H

    1993-01-01

    An acyl spin-label derivative of 5-aminoeosin (5-SLE) was chemically synthesized and employed in studies of rotational dynamics of the free probe and of the probe when bound noncovalently to bovine serum albumin using the spectroscopic techniques of fluorescence anisotropy decay and electron paramagnetic resonance (EPR) and their long-lifetime counterparts phosphorescence anisotropy decay and saturation transfer EPR. Previous work (Beth, A. H., Cobb, C. E., and J. M. Beechem, 1992. Synthesis and characterization of a combined fluorescence, phosphorescence, and electron paramagnetic resonance probe. Society of Photo-Optical Instrumentation Engineers. Time-Resolved Laser Spectroscopy III. 504-512) has shown that the spin-label moiety only slightly altered the fluorescence and phosphorescence lifetimes and quantum yields of 5-SLE when compared with 5-SLE whose nitroxide had been reduced with ascorbate and with the diamagnetic homolog 5-acetyleosin. In the present work, we have utilized time-resolved fluorescence anisotropy decay and linear EPR spectroscopies to observe and quantitate the psec motions of 5-SLE in solution and the nsec motions of the 5-SLE-bovine serum albumin complex. Time-resolved phosphorescence anisotropy decay and saturation transfer EPR studies have been carried out to observe and quantitate the microseconds motions of the 5-SLE-albumin complex in glycerol/buffer solutions of varying viscosity. These latter studies have enabled a rigorous comparison of rotational correlation times obtained from these complementary techniques to be made with a single probe. The studies described demonstrate that it is possible to employ a single molecular probe to carry out the full range of fluorescence, phosphorescence, EPR, and saturation transfer EPR studies. It is anticipated that "dual" molecular probes of this general type will significantly enhance capabilities for extracting dynamics and structural information from macromolecules and their functional

  20. High spin rotations of nuclei with the harmonic oscillator potential

    International Nuclear Information System (INIS)

    Cerkaski, M.; Szymanski, Z.

    1978-01-01

    Calculations of the nuclear properties at high angular momentum have been performed recently. They are based on the liquid drop model of a nucleus and/or on the assumption of the single particle shell structure of the nucleonic motion. The calculations are usually complicated and involve long computer codes. In this article we shall discuss general trends in fast rotating nuclei in the approximation of the harmonic oscillator potential. We shall see that using the Bohr Mottelson simplified version of the rigorous solution of Valatin one can perform a rather simple analysis of the rotational bands, structure of the yrast line, moments of inertia etc. in the rotating nucleus. While the precision fit to experimental data in actual nuclei is not the purpose of this paper, one can still hope to reach some general understanding within the model of the simple relations resulting in nuclei at high spin. (author)

  1. Nonlinear quantum dynamics in diatomic molecules: Vibration, rotation and spin

    International Nuclear Information System (INIS)

    Yang, Ciann-Dong; Weng, Hung-Jen

    2012-01-01

    Highlights: ► This paper reveals the internal nonlinear dynamics embedded in a molecular quantum state. ► Analyze quantum molecular dynamics in a deterministic way, while preserving the consistency with probability interpretation. ► Molecular vibration–rotation interaction and spin–orbital coupling are considered simultaneously. ► Spin is just the remnant angular motion when orbital angular momentum is zero. ► Spin is the “zero dynamics” of nonlinear quantum dynamics. - Abstract: For a given molecular wavefunction Ψ, the probability density function Ψ ∗ Ψ is not the only information that can be extracted from Ψ. We point out in this paper that nonlinear quantum dynamics of a diatomic molecule, completely consistent with the probability prediction of quantum mechanics, does exist and can be derived from the quantum Hamilton equations of motion determined by Ψ. It can be said that the probability density function Ψ ∗ Ψ is an external representation of the quantum state Ψ, while the related Hamilton dynamics is an internal representation of Ψ, which reveals the internal mechanism underlying the externally observed random events. The proposed internal representation of Ψ establishes a bridge between nonlinear dynamics and quantum mechanics, which allows the methods and tools already developed by the former to be applied to the latter. Based on the quantum Hamilton equations of motion derived from Ψ, vibration, rotation and spin motions of a diatomic molecule and the interactions between them can be analyzed simultaneously. The resulting dynamic analysis of molecular motion is compared with the conventional probability analysis and the consistency between them is demonstrated.

  2. Nuclear spin optical rotation and Faraday effect in gaseous and liquid water.

    Science.gov (United States)

    Pennanen, Teemu S; Ikäläinen, Suvi; Lantto, Perttu; Vaara, Juha

    2012-05-14

    Nuclear spin optical rotation (NSOR) of linearly polarized light, due to the nuclear spins through the Faraday effect, provides a novel probe of molecular structure and could pave the way to optical detection of nuclear magnetization. We determine computationally the effects of the liquid medium on NSOR and the Verdet constant of Faraday rotation (arising from an external magnetic field) in water, using the recently developed theory applied on a first-principles molecular dynamics trajectory. The gas-to-liquid shifts of the relevant antisymmetric polarizability and, hence, NSOR magnitude are found to be -14% and -29% for (1)H and (17)O nuclei, respectively. On the other hand, medium effects both enhance the local electric field in water and, via bulk magnetization, the local magnetic field. Together these two effects partially cancel the solvation influence on the single-molecular property. We find a good agreement for the hydrogen NSOR with a recent pioneering experiment on H(2)O(l).

  3. Hawking radiation of spin-1 particles from a three-dimensional rotating hairy black hole

    Energy Technology Data Exchange (ETDEWEB)

    Sakalli, I.; Ovgun, A., E-mail: ali.ovgun@emu.edu.tr [Eastern Mediterranean University Famagusta, North Cyprus, Department of Physics (Turkey)

    2015-09-15

    We study the Hawking radiation of spin-1 particles (so-called vector particles) from a three-dimensional rotating black hole with scalar hair using a Hamilton–Jacobi ansatz. Using the Proca equation in the WKB approximation, we obtain the tunneling spectrum of vector particles. We recover the standard Hawking temperature corresponding to the emission of these particles from a rotating black hole with scalar hair.

  4. PREFACE: 13th International Conference on Muon Spin Rotation, Relaxation and Resonance

    Science.gov (United States)

    2014-12-01

    The 13th International Conference on Muon Spin Rotation, Relaxation and Resonance (μSR2014) organized by the Laboratory for Muon Spin Spectroscopy, Paul Scherrer Institute in collaboration with the University of Zurich and the University of Fribourg, was held in Grindelwald, Switzerland from 1st to 6th June 2014. The conference provided a forum for researchers from around the world with interests in the applications of μSR to study a wide range of topics including condensed matter physics, materials and molecular sciences, chemistry and biology. Polarized muons provide a unique and versatile probe of matter, enabling studies at the atomic level of electronic structure and dynamics in a wide range of systems. The conference was the thirteenth in a series, which began in Rorschach in 1978 and it took place for the third time in Switzerland. The previous conferences were held in Cancun, Mexico (2011), Tsukuba, Japan (2008), Oxford, UK (2005), Williamsburg, USA (2002), Les Diablerets, Switzerland (1999), Nikko, Japan (1996), Maui, USA (1993), Oxford, UK (1990), Uppsala, Sweden (1986), Shimoda, Japan (1983), Vancouver, Canada (1980), and Rorschach, Switzerland (1978). These conference proceedings contain 67 refereed publications from presentations covering magnetism, superconductivity, chemistry, semiconductors, biophysics and techniques. The conference logo, displayed in the front pages of these proceedings, represents both the location of μSR2014 in the Alps and the muon-spin rotation technique. The silhouette represents the famous local mountains Eiger, Mönch and Jungfrau as drawn by the Swiss painter Ferdinand Hodler and the apple with arrow is at the same time a citation of the Wilhelm Tell legend and a remembrance of the key role played by the muon spin and the asymmetric muon decay (which for the highest positron energy has an apple like shape). More than 160 participants (including 32 registered as students and 13 as accompanying persons) from 19 countries

  5. Real-space observation of a right-rotating inhomogeneous cycloidal spin spiral by spin-polarized scanning tunneling microscopy in a triple axes vector magnet.

    Science.gov (United States)

    Meckler, S; Mikuszeit, N; Pressler, A; Vedmedenko, E Y; Pietzsch, O; Wiesendanger, R

    2009-10-09

    Using spin-polarized scanning tunneling microscopy performed in a triple axes vector magnet, we show that the magnetic structure of the Fe double layer on W(110) is an inhomogeneous right-rotating cycloidal spin spiral. The magnitude of the Dzyaloshinskii-Moriya vector is extracted from the experimental data using micromagnetic calculations. The result is confirmed by comparison of the measured saturation field along the easy axis to the respective value as obtained from Monte Carlo simulations. We find that the Dzyaloshinskii-Moriya interaction is too weak to destabilize the single domain state. However, it can define the sense of rotation and the cycloidal spiral type once the single domain state is destabilized by dipolar interaction.

  6. Spin-rotation symmetry breaking and triplet superconducting state in doped topological insulator CuxBi2Se3

    Science.gov (United States)

    Zheng, Guo-Qing

    Spontaneous symmetry breaking is an important concept for understanding physics ranging from the elementary particles to states of matter. For example, the superconducting state breaks global gauge symmetry, and unconventional superconductors can break additional symmetries. In particular, spin rotational symmetry is expected to be broken in spin-triplet superconductors. However, experimental evidence for such symmetry breaking has not been obtained so far in any candidate compounds. We report 77Se nuclear magnetic resonance measurements which showed that spin rotation symmetry is spontaneously broken in the hexagonal plane of the electron-doped topological insulator Cu0.3Bi2Se3 below the superconducting transition temperature Tc =3.4 K. Our results not only establish spin-triplet (odd parity) superconductivity in this compound, but also serve to lay a foundation for the research of topological superconductivity (Ref.). We will also report the doping mechanism and superconductivity in Sn1-xInxTe.

  7. Neutron scattering and muon spin rotation as probes of light interstitial transport

    International Nuclear Information System (INIS)

    Brown, D.W.

    1985-01-01

    The transport of light interstitials, specifically of hydrogen isotopes and the positive muon, is studied with the help of microscopic transport models. The principal observables are the differential neutron scattering cross section of the hydrogen isotopes and the muon spin rotation signal of the positive muon. The transport feature of primary interest is coherence arising as a result of persistence of quantum mechanical phase memory. Evaluation of observables is based on the generalized master equation, or alternatively, the stochastic Liouville equation. The latter is applied to obtain the neutron scattering lineshapes for local tunneling systems as well as for extended Bravais and non-Bravais lattices. It is found that the usual form of the stochastic Liouville equation does not address adequately transport among non-degenerate site-states. An appropriate modification is suggested and employed to obtain scattering lineshapes applicable to recent experiments on impurity-trapped hydrogen. The muon spin rotation signal is formulated under the assumption that spin interactions constitute a negligible source of scattering for muon transport. The depolarization function is evaluated for the cases of local tunneling systems and simple models of spatially extended transport. The former addresses consequences of coherence and both address the consequences of the spatial extent of the muon wavefunction. It is found that the depolarization function is sensitive to the wave function extent, and the detail attributable to it is characterized

  8. The new conceptual design of snakes and spin rotators in RHIC

    International Nuclear Information System (INIS)

    Lee, S.Y.; Courant, E.D.

    1990-01-01

    We discuss the generalized snake configurations, which offers either the advantages of shorter total snake length and smaller horizontal orbit displacement in the compact configuration or the dual functions of a snake and a 90 degree spin rotation for the helicity state. The generalized snake is then applied to the polarized proton collision in RHIC. The possible schemes of obtaining high luminosity are discussed

  9. The relativistic rotation of spin and asymptotic behaviour of the form factor of the composite system

    International Nuclear Information System (INIS)

    Trubnikov, S.V.

    1984-01-01

    The relativistic rotation of nucleon spin in addition to deuteron spin leads to the appearance of the new term in the deuteron charge form factor (DCFF). This term is absent in the traditional approaches and essentially influences the asymptotic behaviour of DCFF. General formulae are obtained for the DCFF asymptotics in the relativistic and nonrelativistic impulse approximation

  10. Resonant amplification of neutrino spin rotation in matter and the solar-neutrino problem

    International Nuclear Information System (INIS)

    Akhmedov, E.Kh.

    1988-01-01

    It is shown that in the presence of matter there can occur resonant amplification of the flavor-changing neutrino spin rotation in transverse magnetic fields, which is roughly analogous to the Mikheyev-Smirnov-Wolfenstein effect in neutrino oscillations. Possible consequences for solar neutrinos are briefly discussed. (orig.)

  11. Spin-Rotation Hyperfine Splittings at Moderate to High J Values in Methanol

    Science.gov (United States)

    Xu, Li-Hong; Hougen, Jon T.; Belov, Sergey; Golubiatnikov, G. Yu; Lapinov, Alexander; Ilyushin, V.; Alekseev, E. A.; Mescheryakov, A. A.

    2015-06-01

    In this talk we present a possible explanation, based on torsionally mediated proton-spin-overall-rotation interaction operators, for the surprising observation in Nizhny Novgorod several years ago of doublets in some Lamb-dip sub-millimeter-wave transitions between torsion-rotation states of E symmetry in methanol. These observed doublet splittings, some as large as 70 kHz, were later confirmed by independent Lamb-dip measurements in Kharkov. In this talk we first show the observed J-dependence of the doublet splittings for two b-type Q branches (one from each laboratory), and then focus on our theoretical explanation. The latter involves three topics: (i) group theoretically allowed terms in the spin-rotation Hamiltonian, (ii) matrix elements of these terms between the degenerate components of torsion-rotation E states, calculated using wavefunctions from an earlier global fit of torsion-rotation transitions of methanol in the vt = 0, 1, and 2 states, and (iii) least-squares fits of coefficients of these terms to about 35 experimentally resolved doublet splittings in the quantum number ranges of K = -2 to +2, J = 13 to 34, and vt = 0. Rather pleasing residuals are obtained for these doublet splittings, and a number of narrow transitions, in which no doublet splitting could be detected, are also in agreement with predictions from the theory. Some remaining disagreements between experiment and the present theoretical explanation will be mentioned. G. Yu. Golubiatnikov, S. P. Belov, A. V. Lapinov, "CH_3OH Sub-Doppler Spectroscopy," (Paper MF04) and S.P. Belov, A.V. Burenin, G.Yu. Golubiatnikov, A.V. Lapinov, "What is the Nature of the Doublets in the E-Methanol Lamb-dip Spectra?" (Paper FB07), 68th International Symposium on Molecular Spectroscopy, Columbus, Ohio, June 2013. Li-Hong Xu, J. Fisher, R.M. Lees, H.Y. Shi, J.T. Hougen, J.C. Pearson, B.J. Drouin, G.A. Blake, R. Braakman, "Torsion-Rotation Global Analysis of the First Three Torsional States (vt = 0, 1, 2

  12. Rotation of the swing plane of Foucault's pendulum and Thomas spin precession: two sides of one coin

    International Nuclear Information System (INIS)

    Krivoruchenko, Mikhail I

    2009-01-01

    Using elementary geometric tools, we apply essentially the same methods to derive expressions for the rotation angle of the swing plane of Foucault's pendulum and the rotation angle of the spin of a relativistic particle moving in a circular orbit (the Thomas precession effect). (methodological notes)

  13. Complete snake and rotator schemes for spin polarization in proton rings and large electron rings

    International Nuclear Information System (INIS)

    Steffen, K.

    1983-11-01

    In order to maintain spin polarization in proton rings and large electron rings, some generalized Siberian Snake scheme may be required to make the spin tune almost independent of energy and thus avoid depolarizing resonances. The practical problem of finding such schemes that, at reasonable technical effort, can be made to work over large energy ranges has been addressed before and is here revisited in a broadened view and with added new suggestions. As a result, possibly optimum schemes for electron rings (LEP) and proton rings are described. In the proposed LEP scheme, spin rotation is devised such that, at the interaction points, the spin direction is longitudinal as required for experiments. (orig.)

  14. Spinning targets for laser fusion

    International Nuclear Information System (INIS)

    Baldwin, D.E.; Ryutov, D.D.

    1995-09-01

    Several techniques for spinning the ICF targets up prior to or in the course of their compression are suggested. Interference of the rotational shear flow with Rayleigh-Taylor instability is briefly discussed and possible consequences for the target performance are pointed out

  15. Voltage switching technique for detecting nuclear spin polarization in a quantum dot

    International Nuclear Information System (INIS)

    Takahashi, Ryo; Kono, Kimitoshi; Tarucha, Seigo; Ono, Keiji

    2010-01-01

    We have introduced a source-drain voltage switching technique for studying nuclear spins in a vertical double quantum dot. Switching the source-drain voltage between the spin-blockade state and the zero-bias Coulomb blockade state can tune the energy difference between the spin singlet and triplet, and effectively turn on/off the hyperfine interaction. Since the change in the nuclear spin state affects the source-drain current, nuclear spin properties can only be detected by transport measurement. Using this technique, we have succeeded in measuring the timescale of nuclear spin depolarization. Furthermore, combining this technique and an RF ac magnetic field, we successfully detected continuous-wave NMR signals of 75 As, 69 Ga, and 71 Ga, which are contained in a quantum dot. (author)

  16. Units of rotational information

    Science.gov (United States)

    Yang, Yuxiang; Chiribella, Giulio; Hu, Qinheping

    2017-12-01

    Entanglement in angular momentum degrees of freedom is a precious resource for quantum metrology and control. Here we study the conversions of this resource, focusing on Bell pairs of spin-J particles, where one particle is used to probe unknown rotations and the other particle is used as reference. When a large number of pairs are given, we show that every rotated spin-J Bell state can be reversibly converted into an equivalent number of rotated spin one-half Bell states, at a rate determined by the quantum Fisher information. This result provides the foundation for the definition of an elementary unit of information about rotations in space, which we call the Cartesian refbit. In the finite copy scenario, we design machines that approximately break down Bell states of higher spins into Cartesian refbits, as well as machines that approximately implement the inverse process. In addition, we establish a quantitative link between the conversion of Bell states and the simulation of unitary gates, showing that the fidelity of probabilistic state conversion provides upper and lower bounds on the fidelity of deterministic gate simulation. The result holds not only for rotation gates, but also to all sets of gates that form finite-dimensional representations of compact groups. For rotation gates, we show how rotations on a system of given spin can simulate rotations on a system of different spin.

  17. Local spin structure of the α -RuCl3 honeycomb-lattice magnet observed via muon spin rotation/relaxation

    Science.gov (United States)

    Yamauchi, Ichihiro; Hiraishi, Masatoshi; Okabe, Hirotaka; Takeshita, Soshi; Koda, Akihiro; Kojima, Kenji M.; Kadono, Ryosuke; Tanaka, Hidekazu

    2018-04-01

    We report a muon spin rotation/relaxation (μ SR ) study of single-crystalline samples of the α -RuCl3 honeycomb magnet, which is presumed to be a model compound for the Kitaev-Heisenberg interaction. It is inferred from magnetic susceptibility and specific-heat measurements that the present samples exhibit successive magnetic transitions at different critical temperatures TN with decreasing temperature, eventually falling into the TN=7 K antiferromagnetic (7 K) phase that has been observed in only single-crystalline specimens with the least stacking fault. Via μ SR measurements conducted under a zero external field, we show that such behavior originates from a phase separation induced by the honeycomb plane stacking fault, yielding multiple domains with different TN's. We also perform μ SR measurements under a transverse field in the paramagnetic phase to identify the muon site from the muon-Ru hyperfine parameters. Based on a comparison of the experimental and calculated internal fields at the muon site for the two possible spin structures inferred from neutron diffraction data, we suggest a modulated zigzag spin structure for the 7 K phase, with the amplitude of the ordered magnetic moment being significantly reduced from that expected for the orbital quenched spin-1/2 state.

  18. Spin-transfer torque in spin filter tunnel junctions

    KAUST Repository

    Ortiz Pauyac, Christian

    2014-12-08

    Spin-transfer torque in a class of magnetic tunnel junctions with noncollinear magnetizations, referred to as spin filter tunnel junctions, is studied within the tight-binding model using the nonequilibrium Green\\'s function technique within Keldysh formalism. These junctions consist of one ferromagnet (FM) adjacent to a magnetic insulator (MI) or two FM separated by a MI. We find that the presence of the magnetic insulator dramatically enhances the magnitude of the spin-torque components compared to conventional magnetic tunnel junctions. The fieldlike torque is driven by the spin-dependent reflection at the MI/FM interface, which results in a small reduction of its amplitude when an insulating spacer (S) is inserted to decouple MI and FM layers. Meanwhile, the dampinglike torque is dominated by the tunneling electrons that experience the lowest barrier height. We propose a device of the form FM/(S)/MI/(S)/FM that takes advantage of these characteristics and allows for tuning the spin-torque magnitudes over a wide range just by rotation of the magnetization of the insulating layer.

  19. Spin-transfer torque in spin filter tunnel junctions

    KAUST Repository

    Ortiz Pauyac, Christian; Kalitsov, Alan; Manchon, Aurelien; Chshiev, Mairbek

    2014-01-01

    Spin-transfer torque in a class of magnetic tunnel junctions with noncollinear magnetizations, referred to as spin filter tunnel junctions, is studied within the tight-binding model using the nonequilibrium Green's function technique within Keldysh formalism. These junctions consist of one ferromagnet (FM) adjacent to a magnetic insulator (MI) or two FM separated by a MI. We find that the presence of the magnetic insulator dramatically enhances the magnitude of the spin-torque components compared to conventional magnetic tunnel junctions. The fieldlike torque is driven by the spin-dependent reflection at the MI/FM interface, which results in a small reduction of its amplitude when an insulating spacer (S) is inserted to decouple MI and FM layers. Meanwhile, the dampinglike torque is dominated by the tunneling electrons that experience the lowest barrier height. We propose a device of the form FM/(S)/MI/(S)/FM that takes advantage of these characteristics and allows for tuning the spin-torque magnitudes over a wide range just by rotation of the magnetization of the insulating layer.

  20. METHODOLOGICAL NOTES: Rotation of the swing plane of Foucault's pendulum and Thomas spin precession: two sides of one coin

    Science.gov (United States)

    Krivoruchenko, Mikhail I.

    2009-08-01

    Using elementary geometric tools, we apply essentially the same methods to derive expressions for the rotation angle of the swing plane of Foucault's pendulum and the rotation angle of the spin of a relativistic particle moving in a circular orbit (the Thomas precession effect).

  1. ROTATING STARS AND THE FORMATION OF BIPOLAR PLANETARY NEBULAE. II. TIDAL SPIN-UP

    Energy Technology Data Exchange (ETDEWEB)

    García-Segura, G. [Instituto de Astronomía, Universidad Nacional Autónoma de Mexico, Km. 103 Carr. Tijuana-Ensenada, 22860, Ensenada, B. C. (Mexico); Villaver, E. [Departamento de Física Teórica, Universidad Autónoma de Madrid, Cantoblanco, E-28049 Madrid (Spain); Manchado, A. [Instituto de Astrofísica de Canarias, Via Láctea s/n, E-38200 La Laguna, Tenerife (Spain); Langer, N. [Argelander-Institut für Astronomie, Universität Bonn, D-53121 Bonn (Germany); Yoon, S.-C., E-mail: ggs@astrosen.unam.mx [Astronomy Program, Department of Physics and Astronomy, Seoul National University, Seoul, 151-747 (Korea, Republic of)

    2016-06-01

    We present new binary stellar evolution models that include the effects of tidal forces, rotation, and magnetic torques with the goal of testing planetary nebulae (PNs) shaping via binary interaction. We explore whether tidal interaction with a companion can spin-up the asymptotic giant brach (AGB) envelope. To do so, we have selected binary systems with main-sequence masses of 2.5 M {sub ⊙} and 0.8 M {sub ⊙} and evolve them allowing initial separations of 5, 6, 7, and 8 au. The binary stellar evolution models have been computed all the way to the PNs formation phase or until Roche lobe overflow (RLOF) is reached, whatever happens first. We show that with initial separations of 7 and 8 au, the binary avoids entering into RLOF, and the AGB star reaches moderate rotational velocities at the surface (∼3.5 and ∼2 km s{sup −1}, respectively) during the inter-pulse phases, but after the thermal pulses it drops to a final rotational velocity of only ∼0.03 km s{sup −1}. For the closest binary separations explored, 5 and 6 au, the AGB star reaches rotational velocities of ∼6 and ∼4 km s{sup −1}, respectively, when the RLOF is initiated. We conclude that the detached binary models that avoid entering the RLOF phase during the AGB will not shape bipolar PNs, since the acquired angular momentum is lost via the wind during the last two thermal pulses. This study rules out tidal spin-up in non-contact binaries as a sufficient condition to form bipolar PNs.

  2. Microwave Amplitude Modulation Technique to Measure Spin-Lattice (T 1) and Spin-Spin (T 2) Relaxation Times

    Science.gov (United States)

    Misra, Sushil K.

    The measurement of very short spin-lattice, or longitudinal, relaxation (SLR) times (i.e., 10-10 Misra, 1998), and polymer resins doped with rare-earth ions (Pescia et al., 1999a; Pescia et al. 1999b). The ability to measure such fast SLR data on amorphous Si and copper-chromium-tin spinel led to an understanding of the role of exchange interaction in affecting spin-lattice relaxation, while the data on polymer resins doped with rare-earth ions provided evidence of spin-fracton relaxation (Pescia et al., 1999a, b). But such fast SLR times are not measurable by the most commonly used techniques of saturation- and inversion-recovery (Poole, 1982; Alger, 1968), which only measure spin-lattice relaxation times longer than 10-6 s. A summary of relevant experimental data is presented in Table 1.

  3. Rotation of the swing plane of Foucault's pendulum and Thomas spin precession: two sides of one coin

    Energy Technology Data Exchange (ETDEWEB)

    Krivoruchenko, Mikhail I [Alikhanov Institute for Theoretical and Experimental Physics, Russian Federation State Scientific Center, Moscow (Russian Federation)

    2009-08-31

    Using elementary geometric tools, we apply essentially the same methods to derive expressions for the rotation angle of the swing plane of Foucault's pendulum and the rotation angle of the spin of a relativistic particle moving in a circular orbit (the Thomas precession effect). (methodological notes)

  4. Nuclear spin circular dichroism

    International Nuclear Information System (INIS)

    Vaara, Juha; Rizzo, Antonio; Kauczor, Joanna; Norman, Patrick; Coriani, Sonia

    2014-01-01

    Recent years have witnessed a growing interest in magneto-optic spectroscopy techniques that use nuclear magnetization as the source of the magnetic field. Here we present a formulation of magnetic circular dichroism (CD) due to magnetically polarized nuclei, nuclear spin-induced CD (NSCD), in molecules. The NSCD ellipticity and nuclear spin-induced optical rotation (NSOR) angle correspond to the real and imaginary parts, respectively, of (complex) quadratic response functions involving the dynamic second-order interaction of the electron system with the linearly polarized light beam, as well as the static magnetic hyperfine interaction. Using the complex polarization propagator framework, NSCD and NSOR signals are obtained at frequencies in the vicinity of optical excitations. Hartree-Fock and density-functional theory calculations on relatively small model systems, ethene, benzene, and 1,4-benzoquinone, demonstrate the feasibility of the method for obtaining relatively strong nuclear spin-induced ellipticity and optical rotation signals. Comparison of the proton and carbon-13 signals of ethanol reveals that these resonant phenomena facilitate chemical resolution between non-equivalent nuclei in magneto-optic spectra

  5. Muon spin rotation studies of electronic excitations and magnetism in the vortex cores of superconductors

    International Nuclear Information System (INIS)

    Sonier, J E

    2007-01-01

    The focus of this paper is on recent progress in muon spin rotation (μSR) studies of the vortex cores in type-II superconductors. By comparison of μSR measurements of the vortex core size in a variety of materials with results from techniques that directly probe electronic states, the effect of delocalized quasiparticles on the spatial variation of field in a lattice of interacting vortices has been determined for both single-band and multi-band superconductors. These studies demonstrate the remarkable accuracy of what some still consider an exotic technique. In recent years μSR has also been used to search for magnetism in and around the vortex cores of high-temperature superconductors. As a local probe μSR is specially suited for detecting static or quasistatic magnetism having short-range or random spatial correlations. As discussed in this review, μSR experiments support a generic phase diagram of competing superconducting and magnetic order parameters, characterized by a quantum phase transition to a state where the competing order is spatially nonuniform

  6. High spin structure in 130Ba

    International Nuclear Information System (INIS)

    Singh, Amandeep; Kaur, Navneet; Kumar, A.; Singh, Varinderjit; Sandal, Rohit; Kaur, Rajbir; Behera, B.R.; Singh, K.P.; Singh, G.; Shukla, Aaradhya; Sharma, H.P.; Kumar, Suresh; Kumar Raja, M.; Madhusudan Rao, P.V.; Muralithar, S.; Singh, R.P.; Kumar, Rakesh; Madhvan, M.; Bhowmik, R.K.

    2009-01-01

    Nuclei with mass A ∼130 has been of great interest to experimental studies on high spin states. This is particularly so for the nuclei in the A∼130 region which exhibit a softness to γ. Evidence for characteristics such as shape coexistence and γ-softness has been gathered during the last two decades for many nuclei from Xe to Nd. Another interesting feature of this mass region is the existence of a regular M1 band which has been considered to be a promising candidate for magnetic rotation. In several nuclei of the A ∼130 mass region M1 bands like those observed in the A < 200 mass region are known. One signature of magnetic rotation is the decrease of the B (M1) values with increasing spin. The aim of the work is to study the high spin states and lifetime measurements using the DSAM technique

  7. Coupling between magnetic field and curvature in Heisenberg spins on surfaces with rotational symmetry

    International Nuclear Information System (INIS)

    Carvalho-Santos, Vagson L.; Dandoloff, Rossen

    2012-01-01

    We study the nonlinear σ-model in an external magnetic field applied on curved surfaces with rotational symmetry. The Euler–Lagrange equations derived from the Hamiltonian yield the double sine-Gordon equation (DSG) provided the magnetic field is tuned with the curvature of the surface. A 2π skyrmion appears like a solution for this model and surface deformations are predicted at the sector where the spins point in the opposite direction to the magnetic field. We also study some specific examples by applying the model on three rotationally symmetric surfaces: the cylinder, the catenoid and the hyperboloid.

  8. Homogenization of Doppler broadening in spin-noise spectroscopy

    Science.gov (United States)

    Petrov, M. Yu.; Ryzhov, I. I.; Smirnov, D. S.; Belyaev, L. Yu.; Potekhin, R. A.; Glazov, M. M.; Kulyasov, V. N.; Kozlov, G. G.; Aleksandrov, E. B.; Zapasskii, V. S.

    2018-03-01

    The spin-noise spectroscopy, being a nonperturbative linear optics tool, is still reputed to reveal a number of capabilities specific to nonlinear optics techniques. The effect of the Doppler broadening homogenization discovered in this work essentially widens these unique properties of spin-noise spectroscopy. We investigate spin noise of a classical system—cesium atoms vapor with admixture of buffer gas—by measuring the spin-induced Faraday rotation fluctuations in the region of D 2 line. The line, under our experimental conditions, is strongly inhomogeneously broadened due to the Doppler effect. Despite that, optical spectrum of the spin-noise power has the shape typical for the homogeneously broadened line with a dip at the line center. This fact is in stark contrast with the results of previous studies of inhomogeneous quantum dot ensembles and Doppler broadened atomic systems. In addition, the two-color spin-noise measurements have shown, in a highly spectacular way, that fluctuations of the Faraday rotation within the line are either correlated or anticorrelated depending on whether the two wavelengths lie on the same side or on different sides of the resonance. The experimental data are interpreted in the frame of the developed theoretical model which takes into account both kinetics and spin dynamics of Cs atoms. It is shown that the unexpected behavior of the Faraday rotation noise spectra and effective homogenization of the optical transition in the spin-noise measurements are related to smallness of the momentum relaxation time of the atoms as compared with their spin-relaxation time. Our findings demonstrate abilities of spin-noise spectroscopy for studying dynamic properties of inhomogeneously broadened ensembles of randomly moving spins.

  9. The one-parameter subgroup of rotations generated by spin transformations in three-dimensional real space

    International Nuclear Information System (INIS)

    Gazoya, E.D.K.; Prempeh, E.; Banini, G.K.

    2015-01-01

    The relationship between the spin transformations of the special linear group of order 2, SL (2, C) and the aggregate SO(3) of the three-dimensional pure rotations when considered as a group in itself (and not as a subgroup of the Lorentz group), is investigated. It is shown, by the spinor map X - → AXA ct which is all action of SL(2. C) on the space of Hermitian matrices, that the one- parameter subgroup of rotations generated are precisely those of angles which are multiples 2π. (au)

  10. Spin Chirality of Cu3 and V3 Nanomagnets. 1. Rotation Behavior of Vector Chirality, Scalar Chirality, and Magnetization in the Rotating Magnetic Field, Magnetochiral Correlations.

    Science.gov (United States)

    Belinsky, Moisey I

    2016-05-02

    The rotation behavior of the vector chirality κ, scalar chirality χ, and magnetization M in the rotating magnetic field H1 is considered for the V3 and Cu3 nanomagnets, in which the Dzialoshinsky-Moriya coupling is active. The polar rotation of the field H1 of the given strength H1 results in the energy spectrum characterized by different vector and scalar chiralities in the ground and excited states. The magnetochiral correlations between the vector and scalar chiralities, energy, and magnetization in the rotating field were considered. Under the uniform polar rotation of the field H1, the ground-state chirality vector κI performs sawtooth oscillations and the magnetization vector MI performs the sawtooth oscillating rotation that is accompanied by the correlated transformation of the scalar chirality χI. This demonstrates the magnetochiral effect of the joint rotation behavior and simultaneous frustrations of the spin chiralities and magnetization in the rotating field, which are governed by the correlation between the chiralities and magnetization.

  11. Spin-filter scanning tunneling microscopy : a novel technique for the analysis of spin polarization on magnetic surfaces and spintronic devices

    NARCIS (Netherlands)

    Vera Marun, I.J.

    2010-01-01

    This thesis deals with the development of a versatile technique to measure spin polarization with atomic resolution. A microscopy technique that can measure electronic spin polarization is relevant for characterization of magnetic nanostructures and spintronic devices. Scanning tunneling microscopy

  12. Simultaneous time-optimal control of the inversion of two spin-(1/2) particles

    International Nuclear Information System (INIS)

    Assemat, E.; Lapert, M.; Sugny, D.; Zhang, Y.; Braun, M.; Glaser, S. J.

    2010-01-01

    We analyze the simultaneous time-optimal control of two-spin systems. The two noncoupled spins, which differ in the value of their chemical offsets, are controlled by the same magnetic fields. Using an appropriate rotating frame, we restrict the study to the case of opposite shifts. We then show that the optimal solution of the inversion problem in a rotating frame is composed of a pulse sequence of maximum intensity and is similar to the optimal solution for inverting only one spin by using a nonresonant control field in the laboratory frame. An example is implemented experimentally using nuclear magnetic resonance techniques.

  13. Spin dynamics of the itinerant helimagnet MnSi studied by positive muon spin relaxation

    International Nuclear Information System (INIS)

    Kadono, R.; Matsuzaki, T.; Yamazaki, T.; Kreitzman, S.R.; Brewer, J.H.

    1990-03-01

    The local magnetic fields and spin dynamics of the itinerant helimagnet MnSi(T c ≅ 29.5 K) have been studied experimentally using positive muon spin rotation/relaxation (μ + SR) methods. In the ordered phase (T c ), zero-field μSR was used to measure the hyperfine fields at the muon sites as well as the muon spin-lattice relaxation time T 1 μ . Two magnetically inequivalent interstitial μ + sites were found with hyperfine coupling constants A hf (1) = -3.94 kOe/μ B and A hf (2) = -6.94 kOe/μ B , respectively. In the paramagnetic phase (T > T c ), the muon-nuclear spin double relaxation technique was used to simultaneously but independently determine the spin-lattice relaxation time T 1 Mn of 55 Mn spins and that of positive muons (T 1 μ ) over a wide temperature range (T c 1 Mn and T 1 μ in both phases shows systematic deviations from the predictions of self-consistent renormalization (SCR) theory. (author)

  14. The global percutaneous shuttling technique tip for arthroscopic rotator cuff repair

    Directory of Open Access Journals (Sweden)

    Bryan G. Vopat

    2014-05-01

    Full Text Available Most arthroscopic rotator cuff repairs utilize suture passing devices placed through arthro- scopic cannulas. These devices are limited by the size of the passing device where the suture is passed through the tendon. An alternative technique has been used in the senior author’s practice for the past ten years, where sutures are placed through the rotator cuff tendon using percutaneous passing devices. This technique, dubbed the global percutaneous shuttling technique of rotator cuff repair, affords the placement of sutures from nearly any angle and location in the shoulder, and has the potential advantage of larger suture bites through the tendon edge. These advantages may increase the area of tendon available to compress to the rotator cuff footprint and improve tendon healing and outcomes. The aim of this study is to describe the global percutaneous shuttling (GPS technique and report our results using this method. The GPS technique can be used for any full thickness rotator cuff tear and is particularly useful for massive cuff tears with poor tissue quality. We recently followed up 22 patients with an average follow up of 32 months to validate its usefulness. American Shoulder and Elbow Surgeons scores improved significantly from 37 preoperatively to 90 postoperatively (P<0.0001. This data supports the use of the GPS technique for arthroscopic rotator cuff repair. Further biomechanical studies are currently being performed to assess the improvements in tendon footprint area with this technique.

  15. Effect of nuclear spin on chemical reactions and internal molecular rotation

    International Nuclear Information System (INIS)

    Sterna, L.L.

    1980-12-01

    Part I of this dissertation is a study of the magnetic isotope effect, and results are presented for the separation of 13 C and 12 C isotopes. Two models are included in the theoretical treatment of the effect. In the first model the spin states evolve quantum mechanically, and geminate recombination is calculated by numerically integrating the collision probability times the probability the radical pair is in a singlet state. In the second model the intersystem crossing is treated via first-order rate constants which are average values of the hyperfine couplings. Using these rate constants and hydrodynamic diffusion equations, an analytical solution, which accounts for all collisions, is obtained for the geminate recombination. The two reactions studied are photolysis of benzophenone and toluene and the photolytic decomposition of dibenzylketone (1,3-diphenyl-2-propanone). No magnetic isotope effect was observed in the benzophenone reaction. 13 C enrichment was observed for the dibenzylketone reaction, and this enrichment was substantially enhanced at intermediate viscosities and low temperatures. Part II of this dissertation is a presentation of theory and results for the use of Zeeman spin-lattice relaxation as a probe of methyl group rotation in the solid state. Experimental results are presented for the time and angular dependences of rotational polarization, the methyl group magnetic moment, and methyl-methyl steric interactions. The compounds studied are 2,6-dimethylphenol, methyl iodide, 1,4,5,8-tetramethylanthracene, 1,4,5,8-tetramethylnaphthalene, 1,2,4,5-tetramethylbenzene, and 2,3-dimethylmaleicanhydride

  16. Anisotropic Rotational Diffusion Studied by Nuclear Spin Relaxation and Molecular Dynamics Simulation: An Undergraduate Physical Chemistry Laboratory

    Science.gov (United States)

    Fuson, Michael M.

    2017-01-01

    Laboratories studying the anisotropic rotational diffusion of bromobenzene using nuclear spin relaxation and molecular dynamics simulations are described. For many undergraduates, visualizing molecular motion is challenging. Undergraduates rarely encounter laboratories that directly assess molecular motion, and so the concept remains an…

  17. Spinning like a blue straggler: the population of fast rotating blue straggler stars in ω Centauri

    Energy Technology Data Exchange (ETDEWEB)

    Mucciarelli, A.; Lovisi, L.; Ferraro, F. R.; Dalessandro, E.; Lanzoni, B. [Dipartimento di Fisica and Astronomia, Università degli Studi di Bologna, Viale Berti Pichat 6/2, I-40127 Bologna (Italy); Monaco, L. [European Southern Observatory, Casilla 19001, Santiago (Chile)

    2014-12-10

    By using high-resolution spectra acquired with FLAMES-GIRAFFE at the ESO/VLT, we measured the radial and rotational velocities for 110 blue straggler stars (BSSs) in ω Centauri, the globular cluster-like stellar system harboring the largest known BSS population. According to their radial velocities, 109 BSSs are members of the system. The rotational velocity distribution is very broad, with the bulk of BSSs spinning at less than ∼40 km s{sup –1} (in agreement with the majority of such stars observed in other globular clusters) and a long tail reaching ∼200 km s{sup –1}. About 40% of the sample has v{sub e} sin i > 40 km s{sup –1} and about 20% has v{sub e} sin i > 70 km s{sup –1}. Such a large fraction is very similar to the percentage of fast rotating BSSs observed in M4. Thus, ω Centauri is the second stellar cluster, beyond M4, with a surprisingly high population of fast spinning BSSs. We found a hint of radial behavior for a fraction of fast rotating BSSs, with a mild peak within one core radius, and a possible rise in the external regions (beyond four core radii). This may suggest that recent formation episodes of mass transfer BSSs occurred preferentially in the outskirts of ω Centauri, or that braking mechanisms able to slow down these stars are least efficient in the lowest density environments.

  18. Mechanical generation of spin current

    Directory of Open Access Journals (Sweden)

    Mamoru eMatsuo

    2015-07-01

    Full Text Available We focus the recent results on spin-current generation from mechanical motion such as rigid rotation and elastic deformations. Spin transport theory in accelerating frames is constructed by using the low energy expansion of the generally covariant Dirac equation. Related issues on spin-manipulation by mechanical rotation are also discussed.

  19. Episodic Spin-up and Spin-down Torque on Earth

    Science.gov (United States)

    Slabinski, Victor J.; Mendonca, Antonio A.

    2018-04-01

    Variations in Earth rotation angle are traditionally expressed by the time difference (ΔT=TT-UT1) between Terrestrial Time (TT) as told by atomic clocks and Universal Time UT1, the time variable used by the Earth-rotation formula. A plot of ΔT versus TT over the past 160 years shows a continuous curve with approximate straight-line segments with different spans of order ~20 years. Removing the tidal and seasonal variations from the data gives these line segments which represent the “decadal variations” in Earth rotation.The slope of a straight-line segment is proportional to the departure of Earth rotation rate from a reference value at the time. The change in slope over the relatively short time between segments indicates an episodic spin-up or spin-down in Earth rotation. The daily combination of VLBI, SLR, and other modern data available since 1973 gives us accurate, daily values of ΔT and the corresponding LOD (Length Of Day) values during these episodes. These allow us to determine the rotational acceleration occurring then.The three largest spin-speed changes found during the VLBI era have the following characteristics:Episode _____________ Duration__ ΔLOD__LOD Rate1983 Dec 30-1984 Jan 28 ... 29 d ...-0.65 ms ..-8.3 ms/y ..........spin-up1989 Mar 15-1989 May 23 ...69 d ....0.68 .......+3.6 ..............spin-down1994 Jan 21-2001 Apr 01 ... 6.5 y ...-2.2 .........-0.36 ..extended spin-upFor the first two episodes listed, we find the acceleration grows from zero (or at least a relatively small value) to its extreme value in ~1 day, stays approximately constant at this value for 29 or 69 days, and then decays back to zero over ~1 day. The acceleration, while it occurs, gives an LOD rate much greater than the 0.02 ms/y rate from tidal friction.The third episode shows that occasionally a several-year-long episode occurs. The acceleration magnitude is smaller but can make a larger total change in LOD (and spin rate). Tidal friction requires >100 y to equal

  20. Microscopic magnetic nature of layered cobalt dioxides investigated by muon-spin rotation and relaxation

    International Nuclear Information System (INIS)

    Sugiyama, Jun; Ikedo, Yutaka; Mukai, Kazuhiko; Nozaki, Hiroshi; Russo, Peter L.; Ansaldo, Eduardo J.; Brewer, Jess H.; Andreica, Daniel; Amato, Alex

    2009-01-01

    In order to elucidate the nature of layered cobalt dioxides A x CoO 2 , we have investigated their microscopic magnetism by means of positive muon-spin rotation and relaxation (μ + SR) spectroscopy, in particular for A=Li, Na, and K. The dome-shaped magnetic phase diagram for Na x CoO 2 with x≥0.75 suggests the competition between the spin concentration and geometrical frustration on the two-dimensional triangular lattice of the CoO 2 plane. The additional experiment on Li x CoO 2 and K x CoO 2 indicates both a weakly coupled regime for the d electrons in the CoO 2 plane and an ignorable weak effect of the inter-plane interaction on their magnetic order at low T.

  1. Exploiting adiabatically switched RF-field for manipulating spin hyperpolarization induced by parahydrogen

    International Nuclear Information System (INIS)

    Kiryutin, Alexey S.; Yurkovskaya, Alexandra V.; Lukzen, Nikita N.; Ivanov, Konstantin L.; Vieth, Hans-Martin

    2015-01-01

    A method for precise manipulation of non-thermal nuclear spin polarization by switching a RF-field is presented. The method harnesses adiabatic correlation of spin states in the rotating frame. A detailed theory behind the technique is outlined; examples of two-spin and three-spin systems prepared in a non-equilibrium state by Para-Hydrogen Induced Polarization (PHIP) are considered. We demonstrate that the method is suitable for converting the initial multiplet polarization of spins into net polarization: compensation of positive and negative lines in nuclear magnetic resonance spectra, which is detrimental when the spectral resolution is low, is avoided. Such a conversion is performed for real two-spin and three-spin systems polarized by means of PHIP. Potential applications of the presented technique are discussed for manipulating PHIP and its recent modification termed signal amplification by reversible exchange as well as for preparing and observing long-lived spin states

  2. Rotational acceleration during head impact resulting from different judo throwing techniques.

    Science.gov (United States)

    Murayama, Haruo; Hitosugi, Masahito; Motozawa, Yasuki; Ogino, Masahiro; Koyama, Katsuhiro

    2014-01-01

    Most severe head injuries in judo are reported as acute subdural hematoma. It is thus necessary to examine the rotational acceleration of the head to clarify the mechanism of head injuries. We determined the rotational acceleration of the head when the subject is thrown by judo techniques. One Japanese male judo expert threw an anthropomorphic test device using two throwing techniques, Osoto-gari and Ouchi-gari. Rotational and translational head accelerations were measured with and without an under-mat. For Osoto-gari, peak resultant rotational acceleration ranged from 4,284.2 rad/s(2) to 5,525.9 rad/s(2) and peak resultant translational acceleration ranged from 64.3 g to 87.2 g; for Ouchi-gari, the accelerations respectively ranged from 1,708.0 rad/s(2) to 2,104.1 rad/s(2) and from 120.2 g to 149.4 g. The resultant rotational acceleration did not decrease with installation of an under-mat for both Ouchi-gari and Osoto-gari. We found that head contact with the tatami could result in the peak values of translational and rotational accelerations, respectively. In general, because kinematics of the body strongly affects translational and rotational accelerations of the head, both accelerations should be measured to analyze the underlying mechanism of head injury. As a primary preventative measure, throwing techniques should be restricted to participants demonstrating ability in ukemi techniques to avoid head contact with the tatami.

  3. Rotational velocities of low-mass stars

    International Nuclear Information System (INIS)

    Stauffer, J.B.; Hartmann, L.W.; Harvard-Smithsonian Center for Astrophysics, Cambridge, MA)

    1986-01-01

    The rotational velocities of stars provide important clues to how stars form and evolve. Yet until recently, studies of stellar rotation were limited to stars more massive than the sun. This is beginning to change, and an observational outline of the rotational velocity evolution of stars less massive than the sun can now be provided. Low-mass stars rotate slowly during the early stages of premain-sequence evolution, and spin up as they contract to the main sequence. This spin-up culminates in a brief period of very rapid rotation at an age of order 50 million years. Physical interpretation of this increase in rotation and the subsequent main-sequence spin-down are complicated by the possibility of differential internal rotation. The observed rapidity of spin-down among G dwarfs suggests that initially only the outer convective envelopes of these stars are slowed. The data suggest an intrinsic spread in angular momentum among young stars of the same mass and age, a spread which is apparently minimized by the angular-momentum loss mechanism in old low-mass stars. 83 references

  4. Fast spin echo MRI techniques. Contrast characteristics and clinical potential. Techniques d'IRM en fast spin echo. Caracteristiques de contraste et potentiels cliniques

    Energy Technology Data Exchange (ETDEWEB)

    Melki, P.; Mulkern, R.V.; Dacher, J.N.; Helenon, O.; Higuchi, N. (Harvard Medical School, Boston, MA (United States)); Oshio, K.; Jolesz, F. (Keio Univ., Tokyo (Japan)); Pourcelot, L. (Hopital Bretonneau, 37 - Tours (France)); Einstein, S. (General Electric Medical System, Milwaukee, WI (United States))

    1993-03-01

    Based on partial RF echo planar principles, Fast Spin Echo techniques (FSE) were implemented on high field systems. These methods produce image quality and contrast which resemble to conventional spin echo (SE) techniques. By reducing acquisition times by factors between 1.4 and 16 over SE methods, FSE allows for several imaging options usually prohibitive with conventional spin echo (SE) sequences. These include fast scans (especially breathold acquisitions); improved T2 contrast with longer TR intervals; increased spatial resolution with the use of larger image matrices and/or smaller fields of view; and 3D volume imaging with a 3D multislab FSE technique. Contrast features of FSE techniques are directly comparable to those of multiple echo SE sequences using the same echo spacing than FSE methods. However, essential contrast differences existing between the FSE sequences and their routine asymmetric dual SE counterpart can be identified. Decreased magnetic susceptibility effects and increased fat signal present within T2 weighted images compared to conventional dual SE images are due to the use of shorter echo spacings employed in FSE sequences. Off-resonance irradiation inherent to the use of a large number of radio frequency pulses in shown to results in dramatic magnetization contrast transfer effects in FSE images acquired in multislice mode.

  5. Spin transport in non-inertial frame

    Energy Technology Data Exchange (ETDEWEB)

    Chowdhury, Debashree, E-mail: debashreephys@gmail.com; Basu, B., E-mail: sribbasu@gmail.com

    2014-09-01

    The influence of acceleration and rotation on spintronic applications is theoretically investigated. In our formulation, considering a Dirac particle in a non-inertial frame, different spin related aspects are studied. The spin current appearing due to the inertial spin–orbit coupling (SOC) is enhanced by the interband mixing of the conduction and valence band states. Importantly, one can achieve a large spin current through the k{sup →}.p{sup →} method in this non-inertial frame. Furthermore, apart from the inertial SOC term due to acceleration, for a particular choice of the rotation frequency, a new kind of SOC term can be obtained from the spin rotation coupling (SRC). This new kind of SOC is of Dresselhaus type and controllable through the rotation frequency. In the field of spintronic applications, utilizing the inertial SOC and SRC induced SOC term, theoretical proposals for the inertial spin filter, inertial spin galvanic effect are demonstrated. Finally, one can tune the spin relaxation time in semiconductors by tuning the non-inertial parameters.

  6. Rotational Acceleration during Head Impact Resulting from Different Judo Throwing Techniques

    OpenAIRE

    MURAYAMA, Haruo; HITOSUGI, Masahito; MOTOZAWA, Yasuki; OGINO, Masahiro; KOYAMA, Katsuhiro

    2014-01-01

    Most severe head injuries in judo are reported as acute subdural hematoma. It is thus necessary to examine the rotational acceleration of the head to clarify the mechanism of head injuries. We determined the rotational acceleration of the head when the subject is thrown by judo techniques. One Japanese male judo expert threw an anthropomorphic test device using two throwing techniques, Osoto-gari and Ouchigari. Rotational and translational head accelerations were measured with and without an ...

  7. Kinetic study of formic acid oxidation on Ti/IrO{sub 2} electrodes prepared using the spin coating deposition technique

    Energy Technology Data Exchange (ETDEWEB)

    Fierro, Stephane, E-mail: stephane.fierro@epfl.c [Institute of Chemical Sciences and Engineering, Swiss Federal Institute of Technology, ISIC-EPFL, CH-1015 Lausanne (Switzerland); Comninellis, Christos [Institute of Chemical Sciences and Engineering, Swiss Federal Institute of Technology, ISIC-EPFL, CH-1015 Lausanne (Switzerland)

    2010-09-30

    In the first part of this paper, IrO{sub 2} electrodes produced by thermal decomposition of H{sub 2}IrCl{sub 6} precursor were manufactured using the spin coating deposition technique, where centrifugal forces spread the precursor solution with simultaneous evaporation of the solvent on the rotating Ti substrate. It was found using this technique, that it is possible to obtain thin and uniform IrO{sub 2} coatings with controlled loadings. The influence of the concentration of iridium salt in the precursor solution (c{sub 0}) as well as the influence of the rotation speed at which the substrate spins ({omega}) on the IrO{sub 2} loading have been studied using voltammetric charge measurements. From these results, a simple relation has been proposed for the estimation of the IrO{sub 2} loading for a given c{sub 0} and {omega}. In the second part of this paper and from measurements performed using different IrO{sub 2} loadings and formic acid concentrations, the kinetic parameters of the oxidation of formic acid have been quantitatively determined using a model that involves the redox couple IrO{sub 3}/IrO{sub 2} as mediator of this reaction. Furthermore, using the kinetic parameters obtained together with the Nernst equation and the I-V curves of the supporting electrolyte (1 M HClO{sub 4}), theoretical I-V curves could be constructed for different concentrations of formic acid and different IrO{sub 2} loadings.

  8. Unraveling multi-spin effects in rotational resonance nuclear magnetic resonance using effective reduced density matrix theory

    International Nuclear Information System (INIS)

    SivaRanjan, Uppala; Ramachandran, Ramesh

    2014-01-01

    A quantum-mechanical model integrating the concepts of reduced density matrix and effective Hamiltonians is proposed to explain the multi-spin effects observed in rotational resonance (R 2 ) nuclear magnetic resonance (NMR) experiments. Employing this approach, the spin system of interest is described in a reduced subspace inclusive of its coupling to the surroundings. Through suitable model systems, the utility of our theory is demonstrated and verified with simulations emerging from both analytic and numerical methods. The analytic results presented in this article provide an accurate description/interpretation of R 2 experimental results and could serve as a test-bed for distinguishing coherent/incoherent effects in solid-state NMR

  9. Unraveling multi-spin effects in rotational resonance nuclear magnetic resonance using effective reduced density matrix theory

    Energy Technology Data Exchange (ETDEWEB)

    SivaRanjan, Uppala; Ramachandran, Ramesh, E-mail: rramesh@iisermohali.ac.in [Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, Manauli, P.O. Box-140306, Mohali, Punjab (India)

    2014-02-07

    A quantum-mechanical model integrating the concepts of reduced density matrix and effective Hamiltonians is proposed to explain the multi-spin effects observed in rotational resonance (R{sup 2}) nuclear magnetic resonance (NMR) experiments. Employing this approach, the spin system of interest is described in a reduced subspace inclusive of its coupling to the surroundings. Through suitable model systems, the utility of our theory is demonstrated and verified with simulations emerging from both analytic and numerical methods. The analytic results presented in this article provide an accurate description/interpretation of R{sup 2} experimental results and could serve as a test-bed for distinguishing coherent/incoherent effects in solid-state NMR.

  10. Fast spin echo MRI techniques. Contrast characteristics and clinical potential

    International Nuclear Information System (INIS)

    Melki, P.; Mulkern, R.V.; Dacher, J.N.; Helenon, O.; Higuchi, N.; Oshio, K.; Jolesz, F.; Pourcelot, L.; Einstein, S.

    1993-01-01

    Based on partial RF echo planar principles, Fast Spin Echo techniques (FSE) were implemented on high field systems. These methods produce image quality and contrast which resemble to conventional spin echo (SE) techniques. By reducing acquisition times by factors between 1.4 and 16 over SE methods, FSE allows for several imaging options usually prohibitive with conventional spin echo (SE) sequences. These include fast scans (especially breathold acquisitions); improved T2 contrast with longer TR intervals; increased spatial resolution with the use of larger image matrices and/or smaller fields of view; and 3D volume imaging with a 3D multislab FSE technique. Contrast features of FSE techniques are directly comparable to those of multiple echo SE sequences using the same echo spacing than FSE methods. However, essential contrast differences existing between the FSE sequences and their routine asymmetric dual SE counterpart can be identified. Decreased magnetic susceptibility effects and increased fat signal present within T2 weighted images compared to conventional dual SE images are due to the use of shorter echo spacings employed in FSE sequences. Off-resonance irradiation inherent to the use of a large number of radio frequency pulses in shown to results in dramatic magnetization contrast transfer effects in FSE images acquired in multislice mode

  11. Spin spring behavior in exchange coupled soft and high-coercivity hard ferromagnets.

    Energy Technology Data Exchange (ETDEWEB)

    Shull, R. D.; Shapiro, A. J.; Gornakov, V. S.; Nikitenko, V. I.; Jiang, J. S.; Kaper, H.; Leaf, G.; Bader, S. D.

    2000-11-01

    The magnetization reversal processes in an epitaxial Fe/Sm{sub 2}Co{sub 7} structure were investigated using the magneto-optical indicator film technique. The dependence of the magnitude and the orientation of the structure average magnetization have been studied on both cycling and rotating the external magnetic field. It was discovered that the magnetization reversal of the soft ferromagnet can proceed by formation of not only one-dimensional, but also two-dimensional, exchange spin springs. Experimental data is compared with a theoretical estimation of the rotational hysteresis loop for a spin system containing a one-dimensional exchange spring.

  12. Properties of rotational bands at the spin limit in A {approximately} 50, A {approximately} 65 and A {approximately} 110 nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Janzen, V.P.; Andrews, H.R.; Ball, G.C. [Chalk River Labs., Ontario (Canada)] [and others

    1996-12-31

    There is now widespread evidence for the smooth termination of rotational bands in A {approx_equal} 110 nuclei at spins of 40-to-50{Dirac_h}s. The characteristics of these bands are compared to those of bands recently observed to high spin in {sup 64}Zn and {sup 48}Cr, studied with the 8{pi} {gamma}-ray spectrometer coupled to the Chalk River miniball charged-particle-detector array.

  13. Spin Hall conductance in a Y-shaped junction device in presence of tunable spin-orbit coupling

    Science.gov (United States)

    Ganguly, Sudin; Basu, Saurabh

    2017-06-01

    We study spin Hall effect in a three terminal Y-shaped device in presence of tunable spin-orbit (SO) interactions via Landauer-Büttiker formalism. We have evolved a fabrication technique for creating different angular separation between the two arms of the Y-shaped device so as to investigate the effect of angular width on the spin Hall conductance (SHC). A smaller angular separation yields a larger conductance. Also arbitrary orientation of the spin quantization axes yields interesting three dimensional contour maps for the SHC corresponding to different angular separation of the Y-shaped device. In addition to the GSH demonstrating bounded behaviour for different angular separations, there are distinct symmetry axes about which SHC demonstrates reflection symmetry. The results explicitly show breaking of the spin rotational symmetry. Further a systematic study is carried out to compare and contrast between the different SO terms, such as Rashba and Dresselhaus SO interactions and the interplay of the angular separation therein.

  14. Mitigation of rotational instability of high-beta field-reversed configuration by double-sided magnetized plasmoid injection

    Energy Technology Data Exchange (ETDEWEB)

    Itagaki, H.; Inomoto, M. [Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8561 (Japan); Asai, T.; Takahashi, Ts. [College of Science and Technology, Nihon University, 1-8-14 Kanda Surugadai, Chiyoda-ku, Tokyo 101-8308 (Japan)

    2014-03-15

    Active control of destructive rotational instability in a high-beta field-reversed configuration (FRC) plasma was demonstrated by using double-sided plasmoid injection technique. The elliptical deformation of the FRC's cross section was mitigated as a result of substantial suppression of spontaneous spin-up by the plasmoid injection. It was found that the injected plasmoid provided better stability against the rotational mode, suggesting that the compensation of the FRC's decaying magnetic flux might help to suppress its spin-up.

  15. Spin-Mechatronics

    Science.gov (United States)

    Matsuo, Mamoru; Saitoh, Eiji; Maekawa, Sadamichi

    2017-01-01

    We investigate the interconversion phenomena between spin and mechanical angular momentum in moving objects. In particular, the recent results on spin manipulation and spin-current generation by mechanical motion are examined. In accelerating systems, spin-dependent gauge fields emerge, which enable the conversion from mechanical angular momentum into spins. Such a spin-mechanical effect is predicted by quantum theory in a non-inertial frame. Experiments which confirm the effect, i.e., the resonance frequency shift in nuclear magnetic resonance, the stray field measurement of rotating metals, and electric voltage generation in liquid metals, are discussed.

  16. Symmetry fractionalization of visons in Z2 spin liquids

    Science.gov (United States)

    Qi, Yang; Cheng, Meng; Fang, Chen

    In this work we study symmetry fractionalization of vison excitations in topological Z2 spin liquids. We show that in the presence of the full SO (3) spin-rotational symmetry and if there is an odd number of spin-1/2 per unit cell, the symmetry fractionalization of visons is completely fixed. On the other hand, visons can have different classes of symmetry fractionalization if the spin-rotational symmetry is reduced. As a concrete example, we show that visons in the Balents-Fisher-Girvin Z2 spin liquid have crystal symmetry fractionalization classes which are not allowed in SO (3) symmetric spin liquids, due to the reduced spin-rotational symmetry.

  17. Changes in the Earth’s Spin Rotation due to the Atmospheric Effects and Reduction in Glaciers

    Directory of Open Access Journals (Sweden)

    Sung-Ho Na

    2016-12-01

    Full Text Available The atmosphere strongly affects the Earth’s spin rotation in wide range of timescale from daily to annual. Its dominant role in the seasonal perturbations of both the pole position and spinning rate of the Earth is once again confirmed by a comparison of two recent data sets; i the Earth orientation parameter and ii the global atmospheric state. The atmospheric semi-diurnal tide has been known to be a source of the Earth’s spin acceleration, and its magnitude is re-estimated by using an enhanced formulation and an up-dated empirical atmospheric S2 tide model. During the last twenty years, an unusual eastward drift of the Earth’s pole has been observed. The change in the Earth’s inertia tensor due to glacier mass redistribution is directly assessed, and the recent eastward movement of the pole is ascribed to this change. Furthermore, the associated changes in the length of day and UT1 are estimated.

  18. Robust techniques for polarization and detection of nuclear spin ensembles

    Science.gov (United States)

    Scheuer, Jochen; Schwartz, Ilai; Müller, Samuel; Chen, Qiong; Dhand, Ish; Plenio, Martin B.; Naydenov, Boris; Jelezko, Fedor

    2017-11-01

    Highly sensitive nuclear spin detection is crucial in many scientific areas including nuclear magnetic resonance spectroscopy, magnetic resonance imaging (MRI), and quantum computing. The tiny thermal nuclear spin polarization represents a major obstacle towards this goal which may be overcome by dynamic nuclear spin polarization (DNP) methods. The latter often rely on the transfer of the thermally polarized electron spins to nearby nuclear spins, which is limited by the Boltzmann distribution of the former. Here we utilize microwave dressed states to transfer the high (>92 % ) nonequilibrium electron spin polarization of a single nitrogen-vacancy center (NV) induced by short laser pulses to the surrounding 13C carbon nuclear spins. The NV is repeatedly repolarized optically, thus providing an effectively infinite polarization reservoir. A saturation of the polarization of the nearby nuclear spins is achieved, which is confirmed by the decay of the polarization transfer signal and shows an excellent agreement with theoretical simulations. Hereby we introduce the polarization readout by polarization inversion method as a quantitative magnetization measure of the nuclear spin bath, which allows us to observe by ensemble averaging macroscopically hidden polarization dynamics like Landau-Zener-Stückelberg oscillations. Moreover, we show that using the integrated solid effect both for single- and double-quantum transitions nuclear spin polarization can be achieved even when the static magnetic field is not aligned along the NV's crystal axis. This opens a path for the application of our DNP technique to spins in and outside of nanodiamonds, enabling their application as MRI tracers. Furthermore, the methods reported here can be applied to other solid state systems where a central electron spin is coupled to a nuclear spin bath, e.g., phosphor donors in silicon and color centers in silicon carbide.

  19. Spin-orbit beams for optical chirality measurement

    Science.gov (United States)

    Samlan, C. T.; Suna, Rashmi Ranjan; Naik, Dinesh N.; Viswanathan, Nirmal K.

    2018-01-01

    Accurate measurement of chirality is essential for the advancement of natural and pharmaceutical sciences. We report here a method to measure chirality using non-separable states of light with geometric phase-gradient in the circular polarization basis, which we refer to as spin-orbit beams. A modified polarization Sagnac interferometer is used to generate spin-orbit beams wherein the spin and orbital angular momentum of the input Gaussian beam are coupled. The out-of-phase interference between counter-propagating Gaussian beams with orthogonal spin states and lateral-shear or/and linear-phase difference between them results in spin-orbit beams with linear and azimuthal phase gradient. The spin-orbit beams interact efficiently with the chiral medium, inducing a measurable change in the center-of-mass of the beam, using the polarization rotation angle and hence the chirality of the medium are accurately calculated. Tunable dynamic range of measurement and flexibility to introduce large values of orbital angular momentum for the spin-orbit beam, to improve the measurement sensitivity, highlight the techniques' versatility.

  20. Magnetism of iron and nickel from rotationally invariant Hirsch-Fye quantum Monte Carlo calculations

    Science.gov (United States)

    Belozerov, A. S.; Leonov, I.; Anisimov, V. I.

    2013-03-01

    We present a rotationally invariant Hirsch-Fye quantum Monte Carlo algorithm in which the spin rotational invariance of Hund's exchange is approximated by averaging over all possible directions of the spin quantization axis. We employ this technique to perform benchmark calculations for the two- and three-band Hubbard models on the infinite-dimensional Bethe lattice. Our results agree quantitatively well with those obtained using the continuous-time quantum Monte Carlo method with rotationally invariant Coulomb interaction. The proposed approach is employed to compute the electronic and magnetic properties of paramagnetic α iron and nickel. The obtained Curie temperatures agree well with experiment. Our results indicate that the magnetic transition temperature is significantly overestimated by using the density-density type of Coulomb interaction.

  1. Particle-rotation coupling in atomic nuclei

    International Nuclear Information System (INIS)

    Almberger, J.

    1980-01-01

    Recently an increased interest in the rotational nuclei has been spurred by the new experimental high-spin activities and by the possibilities for lower spins to interpret an impressive amount of experimental data by some comparatively simple model calculations. The author discusses the particle modes of excitation for rotational nuclei in the pairing regime where some puzzles in the theoretical description remain to be resolved. A model comparison is made between the particle-rotor and cranking models which have different definitions of the collective rotation. The cranking model is found to imply a smaller value of the quasiparticle spin alignment than the particle-rotor model. Rotational spectra for both even and odd nuclei are investigated with the use of the many-BCS-quasiparticles plus rotor model. This model gives an accurate description of the ground and S-bands in many even-even rare-earth nuclei. However, the discrepancies for odd-A nuclei between theory and experiments point to the importance of additional physical components. Therefore the rotationally induced quadrupole pair field is considered. This field has an effect on the low spin states in odd-A nuclei, but is not sufficient to account for the experimental data. Another topic considered is the interaction matrix element in crossings for given spin between quasiparticle rotational bands. The matrix elements are found to oscillate as a function of the number of particles, thereby influencing the sharpness of the backbending. Finally the low-spin continuation of the S-band is studied and it is shown that such states can be populated selectively by means of one-particle pickup reactions involving high angular momentum transfer. (Auth.)

  2. Band head spin assignment of superdeformed bands in 133Pr using two-parameter formulae

    Science.gov (United States)

    Sharma, Honey; Mittal, H. M.

    2018-03-01

    The two-parameter formulae viz. the power index formula, the nuclear softness formula and the VMI model are adopted to accredit the band head spin (I0) of four superdeformed rotational bands in 133Pr. The technique of least square fitting is used to accredit the band head spin for four superdeformed rotational bands in 133Pr. The root mean deviation among the computed transition energies and well-known experimental transition energies are attained by extracting the model parameters from the two-parameter formulae. The determined transition energies are in excellent agreement with the experimental transition energies, whenever exact spins are accredited. The power index formula coincides well with the experimental data and provides minimum root mean deviation. So, the power index formula is more efficient tool than the nuclear softness formula and the VMI model. The deviation of dynamic moment of inertia J(2) against the rotational frequency is also examined.

  3. Simultaneous rotational and vibrational CARS generation through a multiple-frequency combination technique

    International Nuclear Information System (INIS)

    Alden, M.; Bengtsson, P.E.; Edner, H.

    1987-01-01

    One most promising laser technique for probing combustion processes is coherent anti-Stokes Raman scattering (CARS), which due to its coherent nature and signal strength is applied in several real-world applications. Until today almost all CARS experiments are based on probing the population of molecular vibrational energy levels. However, there are several reasons rotational CARS, i.e. probing of rotational energy levels, may provide a complement to or even a better choice than vibrational CARS. Recently an alternative way to produce rotational CARS spectra is proposed, which is based on a multiple-frequency combination technique. The energy-level diagram for this process is presented. Two dye laser beams at ω/sub r/, and one fix frequency laser beam at ω/sub g/ are employed. ω/sub r,1/ and ω/sub r,2/ are two frequencies of many possible pairs with a frequency difference matching a rotational transition in a molecule. The excitation induced by ω/sub r,1/ and ω/sub r,2/ is then scattered by the narrowband ω/sub g/ beam resulting in a CARS beam ω/sub g/ at ω/sub g/ + ω/sub r,1/ - ω/sub r,2/. An interesting feature with this technique is that it is possible to generate simultaneously a rotational and vibrational CARS spectrum by using a double-folded boxcars phase matching approach. The authors believe that the proposed technique for producing rotational and vibration CARS spectra could be of interest, e.g., when measuring in highly turbulent flows. In this case the rotational CARS spectra could use for temperature measurements in the cooler parts, whereas vibrational CARS are to be preferred when measuring in the hotter parts

  4. Longitudinal and transverse spin dynamics of donor-bound electrons in fluorine-doped ZnSe: Spin inertia versus Hanle effect

    Science.gov (United States)

    Heisterkamp, F.; Zhukov, E. A.; Greilich, A.; Yakovlev, D. R.; Korenev, V. L.; Pawlis, A.; Bayer, M.

    2015-06-01

    The spin dynamics of strongly localized donor-bound electrons in fluorine-doped ZnSe epilayers is studied using pump-probe Kerr rotation techniques. A method exploiting the spin inertia is developed and used to measure the longitudinal spin relaxation time T1 in a wide range of magnetic fields, temperatures, and pump densities. The T1 time of the donor-bound electron spin of about 1.6 μ s remains nearly constant for external magnetic fields varied from zero up to 2.5 T (Faraday geometry) and in a temperature range 1.8-45 K. These findings impose severe restrictions on possible spin relaxation mechanisms. In our opinion they allow us to rule out scattering between free and donor-bound electrons, jumping of electrons between different donor centers, scattering between phonons and donor-bound electrons, and with less certainty charge fluctuations in the environment of the donors caused by the 1.5 ps pulsed laser excitation.

  5. Spin, quadrupole moment, and deformation of the magnetic-rotational band head in Pb193

    Science.gov (United States)

    Balabanski, D. L.; Ionescu-Bujor, M.; Iordachescu, A.; Bazzacco, D.; Brandolini, F.; Bucurescu, D.; Chmel, S.; Danchev, M.; de Poli, M.; Georgiev, G.; Haas, H.; Hübel, H.; Marginean, N.; Menegazzo, R.; Neyens, G.; Pavan, P.; Rossi Alvarez, C.; Ur, C. A.; Vyvey, K.; Frauendorf, S.

    2011-01-01

    The spectroscopic quadrupole moment of the T1/2=9.4(5) ns isomer in Pb193 at an excitation energy Eex=(2585+x) keV is measured by the time-differential perturbed angular distribution method as |Qs|=2.6(3) e b. Spin and parity Iπ=27/2- are assigned to it based on angular distribution measurements. This state is the band head of a magnetic-rotational band, described by the 1i13/2 subshell with the (3s1/2-21h9/21i13/2)11- proton excitation. The pairing-plus-quadrupole tilted-axis cranking calculations reproduce the measured quadrupole moment with a moderate oblate deformation ɛ2=-0.11, similar to that of the 11-proton intruder states, which nuclei in the region. This is the first direct measurement of a quadrupole moment and thus of the deformation of a magnetic-rotational band head.

  6. Drones, quasi-spin or iso-spin. A comparison of many-body techniques for general spin

    International Nuclear Information System (INIS)

    McKenzie, B.J.; Stedman, G.E.

    1976-01-01

    For an effective-spin system with 2S + 1 levels there are a number of possible mappings of spin onto pseudo-fermion operators. The relative merits of three of these methods are investigated by calculating to second order the dispersion relation for coupled spin-phonon modes in crystals containing S = 1 effective spin impurities. It is found that the drone formalism quickly becomes intractable at higher spin values, as does the related quasi-spin formalism developed in contrast with the iso-spin (or Abrinkosov projection) formalism. (author)

  7. Three-dimensional image reconstruction using rotational digital subtraction technique: the initial experience of the clinical application

    International Nuclear Information System (INIS)

    Ouyang Zhongnan; Tang Jun; He Jianjun; Lu Xiaohe; Xun Yanping

    2002-01-01

    Objective: To evaluate the benefit of three-dimensional (3D) reconstruction images with rotational digital subtraction technique for the clinical applications. Methods: Conventional two-dimensional digital substraction angiography (2D DSA) was obtained on A-P and lateral view. Three-dimensional digital subtraction angiography (3D DSA) images were obtained by reconstruction of a rotational acquisition on a C-arm (LCV +, GE Medical Systems) spinning at 40 degrees per second. 53 cases of cerebral angiographies were performed (32 men and 21 women; the age ranged from 19 to 72 years, mean 46.3 years). Results: In this series of 53 cases of cerebral angiographies, 5 cases of arteriovenous malformation were all correctly diagnosed by 3D DSA and 2D DSA. Seven cases were misdiagnosed as intracranial aneurysms at conventional 2D DSA but confirmed to be kinking of the vessel by 3D DSA. 41 cases were confirmed to be intracranial aneurysms. Of the 41 cases, 5 cases were diagnosed as normal at 2D DSA but confirmed to be intracranial aneurysms at 3D DSA. The total consistency rate of 3D DSA and 2D DSA for the diagnosis of intracranial aneurysm is 77.4% (41/53). The consistent test shows that there was consistency between the two modalities (chi-square test, χ 2 = 5.267, P < 0.05). 29 cases were treated with endovascular coil embolization. Among them only 3 cases of the aneurysm's neck could be best visualized by 2D DSA but 29 cases by 3D DSA. Conclusion: 3D reconstruction images with rotational digital subtraction technique is a useful tool to study the vascular diseases using less contrast agent and a lower radiation dose and shortening the examination process. It is replenishment for conventional 2D DSA. This technique enables better diagnosis for intracranial vascular lesion and visualization of complex vascular relationships and structures. It is valuable for surgical planning and interventional procedure

  8. Microwave imaging of spinning object using orbital angular momentum

    Science.gov (United States)

    Liu, Kang; Li, Xiang; Gao, Yue; Wang, Hongqiang; Cheng, Yongqiang

    2017-09-01

    The linear Doppler shift used for the detection of a spinning object becomes significantly weakened when the line of sight (LOS) is perpendicular to the object, which will result in the failure of detection. In this paper, a new detection and imaging technique for spinning objects is developed. The rotational Doppler phenomenon is observed by using the microwave carrying orbital angular momentum (OAM). To converge the radiation energy on the area where objects might exist, the generation method of OAM beams is proposed based on the frequency diversity principle, and the imaging model is derived accordingly. The detection method of the rotational Doppler shift and the imaging approach of the azimuthal profiles are proposed, which are verified by proof-of-concept experiments. Simulation and experimental results demonstrate that OAM beams can still be used to obtain the azimuthal profiles of spinning objects even when the LOS is perpendicular to the object. This work remedies the insufficiency in existing microwave sensing technology and offers a new solution to the object identification problem.

  9. Muon spin rotation studies involving muonium at high pH

    International Nuclear Information System (INIS)

    Ng, B.W.; Stadlbauer, J.M.; Walker, D.C.

    1983-06-01

    The muon spin rotation method was used to determine the muon yields in concentrated KOH solutions and to evaluate Arrhenius parameters for the reaction of muonium with hydroxyl ions in dilute aqueous solutions. This latter reaction is relatively slow due to a substantial activation energy, yet there is no kinetic isotope effect at room temperature. The kinetics are well represented by the relationship log ksub(M) = 14.38 - 2100(+-260)/T. The observed enhancement of the diamagentic muon yield (Psub(D)) from 0.62 to 0.79 as the (KOH) was increased from 0 to 20 M can be accounted for in terms of a 'hot-model' mechanism, by allowing Ksub(M) (or the hot fraction) to vary somewhat. The failure of Psub(D) to reach 1.0 in such concentrated OH - solutions shows that the muons do not all emerge from the epithermal processes of the track as free μ + ions

  10. Design and Analysis of A Spin-Stabilized Projectile Experimental Apparatus

    Science.gov (United States)

    Siegel, Noah; Rodebaugh, Gregory; Elkins, Christopher; van Poppel, Bret; Benson, Michael; Cremins, Michael; Lachance, Austin; Ortega, Raymond; Vanderyacht, Douglas

    2017-11-01

    Spinning objects experience an effect termed `The Magnus Moment' due to an uneven pressure distribution based on rotation within a crossflow. Unlike the Magnus force, which is often small for spin-stabilized projectiles, the Magnus moment can have a strong detrimental effect on aerodynamic flight stability. Simulations often fail to accurately predict the Magnus moment in the subsonic flight regime. In an effort to characterize the conditions that cause the Magnus moment, researchers in this work employed Magnetic Resonance Velocimetry (MRV) techniques to measure three dimensional, three component, sub-millimeter resolution fluid velocity fields around a scaled model of a spinning projectile in flight. The team designed, built, and tested using a novel water channel apparatus that was fully MRI-compliant - water-tight and non-ferrous - and capable of spinning a projectile at a constant rotational speed. A supporting numerical simulation effort informed the design process of the scaled projectile to thicken the hydrodynamic boundary layer near the outer surface of the projectile. Preliminary testing produced two-dimensional and three-dimensional velocity data and revealed an asymmetric boundary layer around the projectile, which is indicative of the Magnus effect.

  11. Percutaneous vertebroplasty with the rotational fluoroscopy imaging technique

    Energy Technology Data Exchange (ETDEWEB)

    Cannavale, Alessandro; Salvatori, Filippo Maria; Wlderk, Andrea; Cirelli, Carlo; D' Adamo, Alessandro; Fanelli, Fabrizio [University of Rome, Vascular and Interventional Unit, Department of Radiological Sciences, Rome (Italy)

    2014-11-15

    To evaluate the feasibility of the rotational angiography unit (RAU) as a single technique to guide percutaneous vertebroplasty (PVP). Twenty-five consecutive patients (35 vertebral bodies, 20 lumbar and 15 thoracic) were treated using RA fluoroscopy. Using a state-of-the-art flat-panel angiographer (Artis zee, Siemens, Erlangen, Germany), rotational acquisitions were obtained in all patients for immediate post-procedure 2D/3D reconstructions. Pre- and postoperative back pain was assessed with the visual analog scale (VAS). Fluoroscopy time, patient radiation dose exposure, technical success, mean procedure time, mean number of rotational acquisitions and procedural complications were recorded. All features were compared with a historical cohort of patients (N = 25) who underwent PVP under CT and mobile C-arm fluoroscopy guidance. In all cases, safe and accurate control of the needle insertion and bone-cement injection was successfully obtained with high-quality fluoroscopy images. One cement leakage was detected in the RAU group, and two leakages were detected in the CT and C-arm fluoroscopy group. Technical features were significantly different between the two groups (RAU vs. CT): mean procedure time: 38.2 min vs. 60.2 min (p = 0.02); median fluoroscopy time: 14.58 and 4.58 min (p = 0.02); median number of rotational acquisitions: 5 vs. 10 (p = 0.02); mean patient dose: 6 ± 1.3 mSv vs. 23 ± 1.3 mSv (p = 0.02). There were minor complications (pain, small hematoma) in two patients (8%) in the study group and three cases (12%) in the control group. RAU guidance is an effective and safe technique for performing PVP because it reduces the procedural time and radiation exposure. (orig.)

  12. A low-background piston-cylinder type hybrid high pressure cell for muon-spin rotation/relaxation experiments

    OpenAIRE

    Shermadini, Z.; Khasanov, R.; Elender, M.; Simutis, G.; Guguchia, Z.; Kamenev, K. V.; Amato, A.

    2017-01-01

    A low background double-wall piston-cylinder-type pressure cell is developed at the Paul Scherrer Institute. The cell is made from BERLYCO-25 (beryllium copper) and MP35N nonmagnetic alloys with the design and dimensions which are specifically adapted to muon-spin rotation/relaxation (muSR) measurements. The mechanical design and performance of the pressure cell are evaluated using finite-element analysis (FEA). By including the measured stress-strain characteristics of the material into the ...

  13. Imaging of the brain using the fast-spin-echo and gradient-spin-echo techniques

    International Nuclear Information System (INIS)

    Umek, W.; Ba-Ssalamah, A.; Prokesch, R.; Mallek, R.; Heimberger, K.; Hittmair, K.

    1998-01-01

    The aim of our study was to compare gradient-spin-echo (GRASE) to fast-spin-echo (FSE) sequences for fast T2-weighted MR imaging of the brain. Thirty-one patients with high-signal-intensity lesions on T2-weighted images were examined on a 1.5-T MR system. The FSE and GRASE sequences with identical sequence parameters were obtained and compared side by side. Image assessment criteria included lesion conspicuity, contrast between different types of normal tissue, and image artifacts. In addition, signal-to-noise, contrast-to-noise, and contrast ratios and were determined. The FSE technique demonstrated more lesions than GRASE and with generally better conspicuity. Smaller lesions in particular were better demonstrated on FSE because of lower image noise and slightly weaker image artifacts. Gray-white differentiation was better on FSE. Ferritin and hemosiderin depositions appeared darker on GRASE, which resulted in better contrast. Fatty tissue was less bright on GRASE. With current standard hardware equipment, the FSE technique seems preferable to GRASE for fast T2-weighted routine MR imaging of the brain. For the assessment of hemosiderin or ferritin depositions, GRASE might be considered. (orig.)

  14. Errors and corrections in the separation of spin-flip and non-spin-flip thermal neutron scattering using the polarization analysis technique

    International Nuclear Information System (INIS)

    Williams, W.G.

    1975-01-01

    The use of the polarization analysis technique to separate spin-flip from non-spin-flip thermal neutron scattering is especially important in determining magnetic scattering cross-sections. In order to identify a spin-flip ratio in the scattering with a particular scattering process, it is necessary to correct the experimentally observed 'flipping-ratio' to allow for the efficiencies of the vital instrument components (polarizers and spin-flippers), as well as multiple scattering effects in the sample. Analytical expressions for these corections are presented and their magnitudes in typical cases estimated. The errors in measurement depend strongly on the uncertainties in the calibration of the efficiencies of the polarizers and the spin-flipper. The final section is devoted to a discussion of polarization analysis instruments

  15. Spin-torsion effects in the hyperfine structure of methanol

    International Nuclear Information System (INIS)

    Coudert, L. H.; Gutlé, C.; Huet, T. R.; Grabow, J.-U.; Levshakov, S. A.

    2015-01-01

    The magnetic hyperfine structure of the non-rigid methanol molecule is investigated experimentally and theoretically. 12 hyperfine patterns are recorded using molecular beam microwave spectrometers. These patterns, along with previously recorded ones, are analyzed in an attempt to evidence the effects of the magnetic spin-torsion coupling due to the large amplitude internal rotation of the methyl group [J. E. M. Heuvel and A. Dymanus, J. Mol. Spectrosc. 47, 363 (1973)]. The theoretical approach setup to analyze the observed data accounts for this spin-torsion in addition to the familiar magnetic spin-rotation and spin-spin interactions. The theoretical approach relies on symmetry considerations to build a hyperfine coupling Hamiltonian and spin-rotation-torsion wavefunctions compatible with the Pauli exclusion principle. Although all experimental hyperfine patterns are not fully resolved, the line position analysis yields values for several parameters including one describing the spin-torsion coupling

  16. Vibration dependence of the tensor spin-spin and scalar spin-spin hyperfine interactions by precision measurement of hyperfine structures of 127I2 near 532 nm

    International Nuclear Information System (INIS)

    Hong Fenglei; Zhang Yun; Ishikawa, Jun; Onae, Atsushi; Matsumoto, Hirokazu

    2002-01-01

    Hyperfine structures of the R(87)33-0, R(145)37-0, and P(132)36-0 transitions of molecular iodine near 532 nm are measured by observing the heterodyne beat-note signal of two I 2 -stabilized lasers, whose frequencies are bridged by an optical frequency comb generator. The measured hyperfine splittings are fit to a four-term Hamiltonian, which includes the electric quadrupole, spin-rotation, tensor spin-spin, and scalar spin-spin interactions, with an accuracy of ∼720 Hz. High-accurate hyperfine constants are obtained from this fit. Vibration dependences of the tensor spin-spin and scalar spin-spin hyperfine constants are determined for molecular iodine, for the first time to our knowledge. The observed hyperfine transitions are good optical frequency references in the 532-nm region

  17. Muon-spin-rotation measurements of the London penetration depths in YBa2Cu3O6.97

    International Nuclear Information System (INIS)

    Puempin, B.; Keller, H.; Kuendig, W.; Odermatt, W.; Savic, I.M.; Schneider, J.W.; Simmler, H.; Zimmermann, P.; Kaldis, E.; Rusiecki, S.; Maeno, Y.; Rossel, C.

    1990-01-01

    Muon-spin-rotation (μSR) experiments on a high-quality sintered YBa 2 Cu 3 O x sample [x=6.970(1)] were performed, in order to obtain an accurate knowledge of the magnitude and the temperature dependence of the magnetic penetration depth in this copper oxide superconductor. Special attention was given to the data analysis. In particular, the systematic errors introduced by different types of analyses were estimated. Our results show that the temperature dependence of the effective penetration depth λ eff into the sintered sample is well described by the two-fluid model, with λ eff (0)=155(10) nm. This behavior of λ eff (T) is consistent with conventional s-wave pairing. With the anisotropy ratio γ=λ c /λ ab =5(1) measured in a previous μSR experiment, the penetration depths λ ab (0)=130(10) nm and λ c (0)=500--800 nm (parallel and perpendicular to the CuO 2 planes, respectively) were extracted. Our results are compared with those obtained by other experimental techniques and theoretical predictions

  18. Electron-spin dynamics in Mn-doped GaAs using time-resolved magneto-optical techniques

    Science.gov (United States)

    Akimov, I. A.; Dzhioev, R. I.; Korenev, V. L.; Kusrayev, Yu. G.; Zhukov, E. A.; Yakovlev, D. R.; Bayer, M.

    2009-08-01

    We study the electron-spin dynamics in p -type GaAs doped with magnetic Mn acceptors by means of time-resolved pump-probe and photoluminescence techniques. Measurements in transverse magnetic fields show a long spin-relaxation time of 20 ns that can be uniquely related to electrons. Application of weak longitudinal magnetic fields above 100 mT extends the spin-relaxation times up to microseconds which is explained by suppression of the Bir-Aronov-Pikus spin relaxation for the electron on the Mn acceptor.

  19. MR cholangiography using a fast spin-echo technique: prospective evaluation in 20 patients

    International Nuclear Information System (INIS)

    Rondeau, Y.; Meduri, B.; Spelle, L.; Gouhiri, M.; Aubert, A.; Scherrer, A.; Soyer, Ph.; Rymer, R.

    1998-01-01

    To evaluate a MR cholangiographic technique using a non breath-hold fast spin-echo technique in patients with suspected bile duct obstruction. Twenty patients with suspected bile duct obstruction were prospectively investigated with MR cholangiography using a T2-weighted non breath-hold fast spin-echo technique (TR 8000-9000 msec, effective TE 120-266 msec, ETL = 16-32, acquisition time = 1-3 min) with a body coil. Results of MR cholangiography were compared to those obtained with endoscopic retrograde cholangiography (n = 20 patients) and endoscopic sonography (n 12 patients) that were considered as reference. MR cholangiography provided high-quality images in 19 out of 20 cases (95 %). MR cholangiography had 100 % sensitivity, 100 % specificity and 73 % accuracy in the diagnosis of bile duct obstruction. MR cholangiography failed to depict small stones (< 3 mm) of the main bile duct in 4 cases in which no bile duct dilation was found. MR cholangiography using a non breath-hold fast spin-echo technique depicts bile duct dilatation with a degree of accuracy comparable to that achieved with endoscopic examination. In the absence of bile duct dilatation, small stones of the main bile duct may be undetected with MR cholangiography. (author)

  20. A new corrective technique for adolescent idiopathic scoliosis (Ucar′s convex rod rotation

    Directory of Open Access Journals (Sweden)

    Bekir Yavuz Ucar

    2014-01-01

    Full Text Available Study Design: Prospective single-center study. Objective: To analyze the efficacy and safety of a new technique of global vertebral correction with convex rod rotation performed on the patients with adolescent idiopathic scoliosis. Summary of Background Data: Surgical goal is to obtain an optimal curve correction in scoliosis surgery. There are various correction techniques. This report describes a new technique of global vertebral correction with convex rod rotation. Materials and Methods: A total of 12 consecutive patients with Lenke type I adolescent idiopathic scoliosis and managed by convex rod rotation technique between years 2012 and 2013 having more than 1 year follow-up were included. Mean age was 14.5 (range = 13-17 years years at the time of operation. The hospital charts were reviewed for demographic data. Measurements of curve magnitude and balance were made on 36-inch standing anteroposterior and lateral radiographs taken before surgery and at most recent follow up to assess deformity correction, spinal balance, and complications related to the instrumentation. Results: Preoperative coronal plane major curve of 62° (range = 50°-72° with flexibility of less than 30% was corrected to 11.5°(range = 10°-14° showing a 81% scoliosis correction at the final follow-up. Coronal imbalance was improved 72% at the most recent follow-up assessment. No complications were found. Conclusion: The new technique of global vertebral correction with Ucar′s convex rod rotation is an effective technique. This method is a vertebral rotation procedure from convex side and it allows to put screws easily to the concave side.

  1. Analysis of state-of-the-art single-thruster attitude control techniques for spinning penetrator

    Science.gov (United States)

    Raus, Robin; Gao, Yang; Wu, Yunhua; Watt, Mark

    2012-07-01

    The attitude dynamics and manoeuvre survey in this paper is performed for a mission scenario involving a penetrator-type spacecraft: an axisymmetric prolate spacecraft spinning around its minor axis of inertia performing a 90° spin axis reorientation manoeuvre. In contrast to most existing spacecraft only one attitude control thruster is available, providing a control torque perpendicular to the spin axis. Having only one attitude thruster on a spinning spacecraft could be preferred for spacecraft simplicity (lower mass, lower power consumption etc.), or it could be imposed in the context of redundancy/contingency operations. This constraint does yield restrictions on the thruster timings, depending on the ratio of minor to major moments of inertia among other parameters. The Japanese Lunar-A penetrator spacecraft proposal is a good example of such a single-thruster spin-stabilised prolate spacecraft. The attitude dynamics of a spinning rigid body are first investigated analytically, then expanded for the specific case of a prolate and axisymmetric rigid body and finally a cursory exploration of non-rigid body dynamics is made. Next two well-known techniques for manoeuvring a spin-stabilised spacecraft, the Half-cone/Multiple Half-cone and the Rhumb line slew, are compared with two new techniques, the Sector-Arc Slew developed by Astrium Satellites and the Dual-cone developed at Surrey Space Centre. Each technique is introduced and characterised by means of simulation results and illustrations based on the penetrator mission scenario and a brief robustness analysis is performed against errors in moments of inertia and spin rate. Also, the relative benefits of each slew algorithm are discussed in terms of slew accuracy, energy (propellant) efficiency and time efficiency. For example, a sequence of half-cone manoeuvres (a Multi-half-cone manoeuvre) tends to be more energy-efficient than one half-cone for the same final slew angle, but more time-consuming. As another

  2. Topological spin excitations induced by an external magnetic field coupled to a surface with rotational symmetry

    International Nuclear Information System (INIS)

    Carvalho-Santos, Vagson L.; Dandoloff, Rossen

    2013-01-01

    We study the Heisenberg model in an external magnetic field on curved surfaces with rotational symmetry. The Euler-Lagrange static equations, derived from the Hamiltonian, lead to the inhomogeneous double sine-Gordon equation. Nonetheless, if the magnetic field is coupled to the metric elements of the surface, and consequently to its curvature, the homogeneous double sine-Gordon equation emerges and a 2π-soliton solution is obtained. In order to satisfy the self-dual equations, surface deformations are predicted to appear at the sector where the spin direction is opposite to the magnetic field. On the basis of the model, we find the characteristic length of the 2π-soliton for three specific rotationally symmetric surfaces: the cylinder, the catenoid, and the hyperboloid. On finite surfaces, such as the sphere, torus, and barrels, fractional 2π-solitons are predicted to appear. (author)

  3. Arthroscopic Double-Row Transosseous Equivalent Rotator Cuff Repair with a Knotless Self-Reinforcing Technique.

    Science.gov (United States)

    Mook, William R; Greenspoon, Joshua A; Millett, Peter J

    2016-01-01

    Rotator cuff tears are a significant cause of shoulder morbidity. Surgical techniques for repair have evolved to optimize the biologic and mechanical variables critical to tendon healing. Double-row repairs have demonstrated superior biomechanical advantages to a single-row. The preferred technique for rotator cuff repair of the senior author was reviewed and described in a step by step fashion. The final construct is a knotless double row transosseous equivalent construct. The described technique includes the advantages of a double-row construct while also offering self reinforcement, decreased risk of suture cut through, decreased risk of medial row overtensioning and tissue strangulation, improved vascularity, the efficiency of a knotless system, and no increased risk for subacromial impingement from the burden of suture knots. Arthroscopic knotless double row rotator cuff repair is a safe and effective method to repair rotator cuff tears.

  4. Titanium dioxide antireflective coating for silicon solar cells by spinning technique

    Energy Technology Data Exchange (ETDEWEB)

    Murozono, M; Kitamura, S

    1982-01-01

    Antireflective (AR) TiO2 films for Si solar cells are presently obtained by coating a solution that is derived from organotitanium compounds (with an acetylacetone ligand and an ethanol solvent) on the Si surface using a spinning technique, and then firing at high temperature. AR film thickness can be controlled by up to 1200 A by changing solution concentration and spin speed. Si solar cells with these AR films exhibit as much as a 50 percent improvement in conversion efficiency over uncoated cells. 12 references.

  5. Accelerated territorial arterial spin labeling based on shared rotating control acquisition: an observer study for validation

    International Nuclear Information System (INIS)

    Kamano, Hironori; Yoshiura, Takashi; Hiwatashi, Akio; Yamashita, Koji; Takayama, Yukihisa; Nagao, Eiki; Sagiyama, Koji; Honda, Hiroshi; Zimine, Ivan

    2012-01-01

    Shared rotating control acquisition can shorten the imaging time of territorial arterial spin labeling (tASL) by 33% compared with the normal control acquisition scheme but potentially results in an inaccurate estimate of vascular territories due to imperfect magnetization transfer compensation. Our purpose was to validate the accuracy of the shared rotating control acquisition method in evaluation of vascular territories. Twenty-four patients underwent tASL at a 3.0-T MRI with the conventional normal control acquisition method. Composite vascular territory maps, in which the blood flows from the right and left internal carotid arteries and the posterior circulation were encoded in red-green-blue, were generated as a normal averaged control-label scheme and as a simulated shared rotating control scheme. Two observers independently reported the most dominant territorial flow in 26 brain regions corresponding to the arterial segments at three post-labeling time points. Inter-reader and inter-method agreements were analyzed using κ statistics. Overall inter-reader agreements were excellent for both the normal control and the shared rotating control methods (κ = 0.98, respectively). Overall inter-method agreement was also excellent (κ = 0.98), although relatively low agreement was noted in the bilateral posterior cerebral artery territories (κ = 0.79 to 0.93). Our results suggested that tASL using shared rotating control acquisition can provide information on the vascular territories comparable to that obtained using the normal control acquisition while substantially shortening the imaging time. (orig.)

  6. Spin, quadrupole moment, and deformation of the magnetic-rotational band head in (193)Pb

    CERN Document Server

    Balabanski, D L; Iordachescu, A; Bazzacco, D; Brandolini, F; Bucurescu, D; Chmel, S; Danchev, M; De Poli, M; Georgiev, G; Haas, H; Hubel, H; Marginean, N; Menegazzo, R; Neyens, G; Pavan, P; Rossi Alvarez, C; Ur, C A; Vyvey, K; Frauendorf, S

    2011-01-01

    The spectroscopic quadrupole moment of the T(1/2) = 9.4(5) ns isomer in (193)Pb at an excitation energy E(ex) = (2585 + x) keV is measured by the time-differential perturbed angular distribution method as vertical bar Q(s)vertical bar = 2.6(3) e b. Spin and parity I(pi) = 27/2(-) are assigned to it based on angular distribution measurements. This state is the band head of a magnetic-rotational band, described by the coupling of a neutron hole in the 1i(13/2) subshell with the (3s(1/2)(-2)1h(9/2)1i(13/2))(11-) proton excitation. The pairing-plus-quadrupole tilted-axis cranking calculations reproduce the measured quadrupole moment with a moderate oblate deformation epsilon(2) = -0.11, similar to that of the 11(-)proton intruder states, which occur in the even-even Pb nuclei in the region. This is the first direct measurement of a quadrupole moment and thus of the deformation of a magnetic-rotational band head.

  7. Muon-spin rotation studies of the flux lattice in {kappa}-(BEDT-TTF){sub 2}Cu(SCN){sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.L. [Saint Andrews Univ. (United Kingdom). Sch. of Phys. and Astron.; Blundell, S.J. [Oxford Univ. (United Kingdom). Dept. of Physics; Pratt, F.L. [RIKEN-RAL, Didcot (United Kingdom); Pattenden, P.A. [Oxford Univ. (United Kingdom). Dept. of Physics; Forgan, E.M. [Birmingham Univ. (United Kingdom). School of Physics and Space Research; Sasaki, T. [Tohoku Univ., Sendai (Japan). Inst. for Materials Research; Aegerter, C.M. [Zurich Univ. (Switzerland). Inst. fuer Physik; Hunt, M. [Zurich Univ. (Switzerland). Inst. fuer Physik; Chow, K.H. [Oxford Univ. (United Kingdom). Dept. of Physics; Hayes, W. [Oxford Univ. (United Kingdom). Dept. of Physics; Singleton, J. [Oxford Univ. (United Kingdom). Dept. of Physics; Keller, H. [Zurich Univ. (Switzerland). Inst. fuer Physik; Savic, I.M. [Zurich Univ. (Switzerland). Inst. fuer Physik

    1997-02-15

    Muon spin rotation ({mu}SR) studies of the vortex lattice in the superconductor {kappa}-(BEDT-TTF){sub 2}Cu(SCN){sub 2} have revealed a crossover from a quasi-2d to a vortex-line lattice structure for fields below a characteristic field B{sub cr}. The {mu}SR-lineshapes measured from the vortex-line lattice have allowed a re-evaluation of the in-plane penetration depth. (orig.)

  8. Design and Simulation of a Spin Rotator for Longitudinal Field Measurements in the Low Energy Muons Spectrometer

    Science.gov (United States)

    Salman, Z.; Prokscha, T.; Keller, P.; Morenzoni, E.; Saadaoui, H.; Sedlak, K.; Shiroka, T.; Sidorov, S.; Suter, A.; Vrankovic, V.; Weber, H.-P.

    We usedGeant4 to accurately model the low energy muons (LEM) beam line, including scattering due to the 10-nm thin carbon foil in the trigger detector. Simulations of the beam line transmission give excellent agreement with experimental results for beam energies higher than ∼ 12keV.We use these simulations to design and model the operation of a spin rotator for the LEM spectrometer, which will enable longitudinal field measurements in the near future.

  9. EPR spin probe and spin label studies of some low molecular and polymer micelles

    Science.gov (United States)

    Wasserman, A. M.; Kasaikin, V. A.; Timofeev, V. P.

    1998-12-01

    The rotational mobility of spin probes of different shape and size in low molecular and polymer micelles has been studied. Several probes having nitroxide fragment localized either in the vicinity of micelle interface or in the hydrocarbon core have been used. Upon increasing the number of carbon atoms in hydrocarbon chain of detergent from 7 to 13 (sodium alkyl sulfate micelles) or from 12 to 16 (alkyltrimethylammonium bromide micelles) the rotational mobility of spin probes is decreased by the factor 1.5-2.0. The spin probe rotational mobility in polymer micelles (the complexes of alkyltrimethylammonium bromides and polymethacrylic or polyacrylic acids) is less than mobility in free micelles of the same surfactants. The study of EPR-spectra of spin labeled polymethacrylic acid (PMA) indicated that formation of water soluble complexes of polymer and alkyltrimethylammonium bromides in alkaline solutions (pH 9) does not affect the polymer segmental mobility. On the other hand, the polymer complexes formation in slightly acidic water solution (pH 6) breaks down the compact PMA conformation, thus increasing the polymer segmental mobility. Possible structures of polymer micelles are discussed.

  10. The lateral crural rein flap: a novel technique for management of tip rotation in primary rhinoplasty.

    Science.gov (United States)

    Kuran, Ismail; Öreroğlu, Ali Rıza; Efendioğlu, Kamran

    2014-09-01

    An important consideration in rhinoplasty is maintenance of the applied tip rotation. Different techniques have been proposed to accomplish this. Loss of rotation after surgery not only results in a derotated tip but also can create a supratip deformity. As a supplement to dorsal reconstruction, the authors introduced and applied the lateral crural rein flap technique, whereby cartilage flaps are created from the cephalic portion of the lateral crura to control and stabilize tip rotation. Eleven patients underwent primary open-approach rhinoplasty that included the lateral crural rein technique; the mean follow-up time was 18 months. Excess cephalic portions of the lateral crura were prepared as medial crura-based cartilaginous flaps and were incorporated into the nasal dorsum (similar to spreader grafts) and stabilized to achieve the desired tip rotation. The lateral crural rein flap technique provided stability to the nasal tip while minimizing derotation in the postoperative period. Long-term follow-up revealed maintenance of the nasal tip rotation and symmetric dorsal aesthetic lines. The lateral crural rein flap technique is effective for controlling nasal tip rotation while reducing lateral crural cephalic excess. Longevity of the applied tip rotation is reinforced by secure attachment of the lower nasal cartilage complex to the midvault structures. 4. © 2014 The American Society for Aesthetic Plastic Surgery, Inc.

  11. Investigation of a Cross-Correlation Based Optical Strain Measurement Technique for Detecting radial Growth on a Rotating Disk

    Science.gov (United States)

    Clem, Michelle M.; Woike, Mark R.

    2013-01-01

    The Aeronautical Sciences Project under NASA`s Fundamental Aeronautics Program is extremely interested in the development of novel measurement technologies, such as optical surface measurements in the internal parts of a flow path, for in situ health monitoring of gas turbine engines. In situ health monitoring has the potential to detect flaws, i.e. cracks in key components, such as engine turbine disks, before the flaws lead to catastrophic failure. In the present study, a cross-correlation imaging technique is investigated in a proof-of-concept study as a possible optical technique to measure the radial growth and strain field on an already cracked sub-scale turbine engine disk under loaded conditions in the NASA Glenn Research Center`s High Precision Rotordynamics Laboratory. The optical strain measurement technique under investigation offers potential fault detection using an applied high-contrast random speckle pattern and imaging the pattern under unloaded and loaded conditions with a CCD camera. Spinning the cracked disk at high speeds induces an external load, resulting in a radial growth of the disk of approximately 50.0-im in the flawed region and hence, a localized strain field. When imaging the cracked disk under static conditions, the disk will be undistorted; however, during rotation the cracked region will grow radially, thus causing the applied particle pattern to be .shifted`. The resulting particle displacements between the two images will then be measured using the two-dimensional cross-correlation algorithms implemented in standard Particle Image Velocimetry (PIV) software to track the disk growth, which facilitates calculation of the localized strain field. In order to develop and validate this optical strain measurement technique an initial proof-of-concept experiment is carried out in a controlled environment. Using PIV optimization principles and guidelines, three potential speckle patterns, for future use on the rotating disk, are developed

  12. Neutron spin echo: A new concept in polarized thermal neutron techniques

    International Nuclear Information System (INIS)

    Mezei, F.

    1980-01-01

    A simple method to change and keep track of neutron beam polarization non-parallel to the magnetic field is described. It makes possible the establishment of a new focusing effect we call neutron spin echo. The technique developed and tested experimentally can be applied in several novel ways, e.g. for neutron spin flipper of superior characteristics, for a very high resolution spectrometer for direct determination of the Fourier transform of the scattering function, for generalised polarization analysis and for the measurement of neutron particle properties with significantly improved precision. (orig.)

  13. Arthroscopic modified Mason-Allen technique for large U- or L-shaped rotator cuff tears.

    Science.gov (United States)

    Jung, Sung-Weon; Kim, Dong-Hee; Kang, Seung-Hoon; Lee, Ji-Heon

    2017-07-01

    While a conventional single- or double-row repair technique could be applied for repair of C-shaped tears, a different surgical strategy should be considered for repair of U- or L-shaped tears because they typically have complex patterns with anterior, posterior, or both mobile leaves. This study was performed to examine the outcomes of the modified Mason-Allen technique for footprint restoration in the treatment of large U- or L-shaped rotator cuff tears. Thirty-two patients who underwent an arthroscopic modified Mason-Allen technique for large U- or L-shaped rotator cuff tears between January 2012 and December 2013 were included in this study. Margin convergence was first performed to reduce the tear gap and tension, and then, an arthroscopic Mason-Allen technique was performed to restore the rotator cuff footprint in a side-to-end repair fashion. All patients were evaluated preoperatively and for a minimum of 2 years of follow-up with a visual analog scale (VAS) for pain, Constant score, and ultrasonography. There was significant improvement in all VAS and Constant scores compared with the preoperative values (P rotator cuff in our data. Overall satisfactory results were achieved in most patients, with the exception of those with severe fatty degeneration. An arthroscopic modified Mason-Allen technique could be an effective and reliable alternative for patients with large U- or L-shaped rotator cuff tears. Case Series, Therapeutic Level IV.

  14. An efficient numerical technique for solving navier-stokes equations for rotating flows

    International Nuclear Information System (INIS)

    Haroon, T.; Shah, T.M.

    2000-01-01

    This paper simulates an industrial problem by solving compressible Navier-Stokes equations. The time-consuming tri-angularization process of a large-banded matrix, performed by memory economical Frontal Technique. This scheme successfully reduces the time for I/O operations even for as large as (40, 000 x 40, 000) matrix. Previously, this industrial problem can solved by using modified Newton's method with Gaussian elimination technique for the large matrix. In the present paper, the proposed Frontal Technique is successfully used, together with Newton's method, to solve compressible Navier-Stokes equations for rotating cylinders. By using the Frontal Technique, the method gives the solution within reasonably acceptance computational time. Results are compared with the earlier works done, and found computationally very efficient. Some features of the solution are reported here for the rotating machines. (author)

  15. Experimental study on the spin-orbit coupling property in low-dimensional semiconductor structures

    International Nuclear Information System (INIS)

    Zhao, Hongming

    2010-01-01

    The spin-orbit coupling and optical properties have been studied in several low-dimensional semiconductor structures. First, the spin dynamics in (001) GaAs/AlGaAs two-dimensional electron gas was investigated by time resolved Kerr rotation technique under a transverse magnetic field. The in-plane spin lifetime is found to be anisotropic. The results show that the electron density in two-dimensional electron gas channel strongly affects the Rashba spin-orbit coupling. Then, a large anisotropy of the magnitude of in-plane conduction electron g factor in asymmetric (001) GaAs/AlGaAs QWs was observed and its tendency of temperature dependence was studied. Second, the experimental study of the in-plane-orientation dependent spin splitting in the C(0001) GaN/AlGaN two-dimensional electron gas at room temperature was reported. The measurement of circular photo-galvanic effect current clearly shows the isotropic in-plane spin splitting in this system for the first time. Third, the first measurement of conduction electron g factor in GaAsN at room temperature was done by using time resolved Kerr rotation technique. It demonstrates that the g factor can be modified drastically by introducing a small amount of nitrogen in GaAs bulk. Finally, the optical characteristic of indirect type II transition in a series of size and shape-controlled linear CdTe/CdSe/CdTe heterostructure nano-rods was studied by steady-state and time resolved photoluminescence. Results show the steady transfer from the direct optical transition (type I) within CdSe to the indirect transition (type II) between CdSe/CdTe as the length of the nano-rods increases. (author)

  16. All-electric spin modulator based on a two-dimensional topological insulator

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Xianbo; Ai, Guoping [School of Computer Science, Jiangxi University of Traditional Chinese Medicine, Nanchang 330004 (China); Liu, Ying; Yang, Shengyuan A., E-mail: shengyuan-yang@sutd.edu.sg [Research Laboratory for Quantum Materials, Singapore University of Technology and Design, Singapore 487372 (Singapore); Liu, Zhengfang [School of Science, East China Jiaotong University, Nanchang 330013 (China); Zhou, Guanghui, E-mail: ghzhou@hunnu.edu.cn [Key Laboratory for Low-Dimensional Structures and Quantum Manipulation (Ministry of Education), and Synergetic Innovation Center for Quantum Effects and Applications, Hunan Normal University, Changsha 410081 (China)

    2016-01-18

    We propose and investigate a spin modulator device consisting of two ferromagnetic leads connected by a two-dimensional topological insulator as the channel material. It exploits the unique features of the topological spin-helical edge states, such that the injected carriers with a non-collinear spin-polarization direction would travel through both edges and show interference effect. The conductance of the device can be controlled in a simple and all-electric manner by a side-gate voltage, which effectively rotates the spin-polarization of the carrier. At low voltages, the rotation angle is linear in the gate voltage, and the device can function as a good spin-polarization rotator by replacing the drain electrode with a non-magnetic material.

  17. Anisotropic in-plane spin splitting in an asymmetric (001 GaAs/AlGaAs quantum well

    Directory of Open Access Journals (Sweden)

    Zhang Xiuwen

    2011-01-01

    Full Text Available Abstract The in-plane spin splitting of conduction-band electron has been investigated in an asymmetric (001 GaAs/Al x Ga1-x As quantum well by time-resolved Kerr rotation technique under a transverse magnetic field. The distinctive anisotropy of the spin splitting was observed while the temperature is below approximately 200 K. This anisotropy emerges from the combined effect of Dresselhaus spin-orbit coupling plus asymmetric potential gradients. We also exploit the temperature dependence of spin-splitting energy. Both the anisotropy of spin splitting and the in-plane effective g-factor decrease with increasing temperature. PACS: 78.47.jm, 71.70.Ej, 75.75.+a, 72.25.Fe,

  18. X-ray wavefront characterization using a rotating shearing interferometer technique.

    Science.gov (United States)

    Wang, Hongchang; Sawhney, Kawal; Berujon, Sébastien; Ziegler, Eric; Rutishauser, Simon; David, Christian

    2011-08-15

    A fast and accurate method to characterize the X-ray wavefront by rotating one of the two gratings of an X-ray shearing interferometer is described and investigated step by step. Such a shearing interferometer consists of a phase grating mounted on a rotation stage, and an absorption grating used as a transmission mask. The mathematical relations for X-ray Moiré fringe analysis when using this device are derived and discussed in the context of the previous literature assumptions. X-ray beam wavefronts without and after X-ray reflective optical elements have been characterized at beamline B16 at Diamond Light Source (DLS) using the presented X-ray rotating shearing interferometer (RSI) technique. It has been demonstrated that this improved method allows accurate calculation of the wavefront radius of curvature and the wavefront distortion, even when one has no previous information on the grating projection pattern period, magnification ratio and the initial grating orientation. As the RSI technique does not require any a priori knowledge of the beam features, it is suitable for routine characterization of wavefronts of a wide range of radii of curvature. © 2011 Optical Society of America

  19. ROTATION STATE OF COMET 103P/HARTLEY 2 FROM RADIO SPECTROSCOPY AT 1 mm

    International Nuclear Information System (INIS)

    Drahus, Michal; Jewitt, David; Guilbert-Lepoutre, Aurelie; Waniak, Waclaw; Hoge, James; Lis, Dariusz C.; Yoshida, Hiroshige; Peng, Ruisheng; Sievers, Albrecht

    2011-01-01

    The nuclei of active comets emit molecules anisotropically from discrete vents. As the nucleus rotates, we expect to observe periodic variability in the molecular emission line profiles, which can be studied through millimeter/submillimeter spectroscopy. Using this technique we investigated the HCN atmosphere of comet 103P/Hartley 2, the target of NASA's EPOXI mission, which had an exceptionally favorable apparition in late 2010. We detected short-term evolution of the spectral line profile, which was stimulated by the nucleus rotation, and which provides evidence for rapid deceleration and excitation of the rotation state. The measured rate of change in the rotation period is +1.00 ± 0.15 minutes day -1 and the period itself is 18.32 ± 0.03 hr, both applicable at the epoch of the EPOXI encounter. Surprisingly, the spin-down efficiency is lower by two orders of magnitude than the measurement in comet 9P/Tempel 1 and the best theoretical prediction. This secures rotational stability of the comet's nucleus during the next few returns, although we anticipate a catastrophic disruption from spin-up as its ultimate fate.

  20. Spin Dynamics in (111) GaAs/AlGaAs Undoped Asymmetric Quantum Wells

    International Nuclear Information System (INIS)

    Wang Gang; Ye Hui-Qi; Shi Zhen-Wu; Wang Wen-Xin; Liu Bao-Li; Xavier Marie; Andrea Balocchi; Thierry Amand

    2012-01-01

    The electron spin dynamics is investigated by the time-resolved Kerr rotation technique in a pair of special GaAs/AlGaAs asymmetric quantum well samples grown on (111)-oriented substrates, whose structures are the same except for their opposite directions of potential asymmetry. A large difference of spin lifetimes between the two samples is observed at low temperature. This difference is interpreted in terms of a cancellation effect between the Dresselhaus spin-splitting term in the conduction band and another term induced by interface inversion asymmetry. The deviation decreases with the increasing temperature, and almost disappears when T > 100 K because the cubic Dresselhaus term becomes more important

  1. Realization of tunable spin-dependent splitting in intrinsic photonic spin Hall effect

    Energy Technology Data Exchange (ETDEWEB)

    Ling, Xiaohui [SZU-NUS Collaborative Innovation Center for Optoelectronic Science and Technology, and Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060 (China); Laboratory for spin photonics, College of Physics and Microelectronic Science, Hunan University, Changsha 410082 (China); Department of Physics and Electronic Information Science, Hengyang Normal University, Hengyang 421002 (China); Yi, Xunong [SZU-NUS Collaborative Innovation Center for Optoelectronic Science and Technology, and Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060 (China); Zhou, Xinxing; Liu, Yachao; Shu, Weixing; Wen, Shuangchun [Laboratory for spin photonics, College of Physics and Microelectronic Science, Hunan University, Changsha 410082 (China); Luo, Hailu, E-mail: hailuluo@hnu.edu.cn [SZU-NUS Collaborative Innovation Center for Optoelectronic Science and Technology, and Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen 518060 (China); Laboratory for spin photonics, College of Physics and Microelectronic Science, Hunan University, Changsha 410082 (China)

    2014-10-13

    We report the realization of tunable spin-dependent splitting in intrinsic photonic spin Hall effect. By breaking the rotational symmetry of a cylindrical vector beam, the intrinsic vortex phases that the two spin components of the vector beam carries, which is similar to the geometric Pancharatnam-Berry phase, are no longer continuous in the azimuthal direction, and leads to observation of spin accumulation at the opposite edge of the beam. Due to the inherent nature of the phase and independency of light-matter interaction, the observed photonic spin Hall effect is intrinsic. Modulating the topological charge of the vector beam, the spin-dependent splitting can be enhanced and the direction of spin accumulation is switchable. Our findings may provide a possible route for generation and manipulation of spin-polarized photons, and enables spin-based photonics applications.

  2. The Spin Move: A Reliable and Cost-Effective Gowning Technique for the 21st Century.

    Science.gov (United States)

    Ochiai, Derek H; Adib, Farshad

    2015-04-01

    Operating room efficiency (ORE) and utilization are considered one of the most crucial components of quality improvement in every hospital. We introduced a new gowning technique that could optimize ORE. The Spin Move quickly and efficiently wraps a surgical gown around the surgeon's body. This saves the operative time expended through the traditional gowning techniques. In the Spin Move, while the surgeon is approaching the scrub nurse, he or she uses the left heel as the fulcrum. The torque, which is generated by twisting the right leg around the left leg, helps the surgeon to close the gown as quickly and safely as possible. From 2003 to 2012, the Spin Move was performed in 1,725 consecutive procedures with no complication. The estimated average time was 5.3 and 7.8 seconds for the Spin Move and traditional gowning, respectively. The estimated time saving for the senior author during this period was 71.875 minutes. Approximately 20,000 orthopaedic surgeons practice in the United States. If this technique had been used, 23,958 hours could have been saved. The money saving could have been $14,374,800.00 (23,958 hours × $600/operating room hour) during the past 10 years. The Spin Move is easy to perform and reproducible. It saves operating room time and increases ORE.

  3. Giant spin rotation under quasiparticle-photoelectron conversion: Joint effect of sublattice interference and spin-orbit coupling

    DEFF Research Database (Denmark)

    Kuemmeth, Ferdinand; Rashba, E I

    2009-01-01

    Spin- and angular-resolved photoemission spectroscopy is a basic experimental tool for unveiling spin polarization of electron eigenstates in crystals. We prove, by using spin-orbit coupled graphene as a model, that photoconversion of a quasiparticle inside a crystal into a photoelectron can...... be accompanied with a dramatic change in its spin polarization, up to a total spin flip. This phenomenon is typical of quasiparticles residing away from the Brillouin-zone center and described by higher rank spinors and results in exotic patterns in the angular distribution of photoelectrons....

  4. Flying spin-qubit gates implemented through Dresselhaus and Rashba spin-orbit couplings

    International Nuclear Information System (INIS)

    Gong, S.J.; Yang, Z.Q.

    2007-01-01

    A theoretical scheme is proposed to implement flying spin-qubit gates based on two semiconductor wires with Dresselhaus and Rashba spin-orbit couplings (SOCs), respectively. It is found that under the manipulation of the Dresselhaus/Rashba SOC, spin rotates around x/y axis in the three-dimensional spin space. By combining the two kinds of manipulations, i.e. connecting the two kinds of semiconductor wires in series, we obtain a universal set of losses flying single-qubit gates including Hadamard, phase, and π/8 gates. A ballistic switching effect of electronic flow is also found in the investigation. Our results may be useful in future spin or nanoscale electronics

  5. Electric-field assisted spin torque nano-oscillator and binary frequency shift keying modulation

    Science.gov (United States)

    Zhang, Xiangli; Chen, Hao-Hsuan; Zhang, Zongzhi; Liu, Yaowen

    2018-04-01

    Electric-controlled magnetization precession introduces technologically relevant possibility for developing spin torque nano-oscillators (STNO) with potential applications in microwave emission. Using the perpendicularly magnetized magnetic tunnel junction (MTJ), we show that the magnetization oscillation frequency can be tuned by the co-action of electric field and spin polarized current. The dynamical phase diagram of MTJ-based STNO is analytically predicted through coordinate transformation from the laboratory frame to the rotation frame, by which the nonstationary out-of-plane magnetization precession process is therefore transformed into the stationary process in the rotation frame. Furthermore, using this STNO as a microwave source, we numerically demonstrate that the bit signal can be transmitted by a binary frequency shift keying (BFSK) modulation technique. The BFSK scheme shows good modulation features with no transient state.

  6. High resolution x-ray fluorescence spectroscopy - a new technique for site- and spin-selectivity

    International Nuclear Information System (INIS)

    Wang, Xin

    1996-12-01

    X-ray spectroscopy has long been used to elucidate electronic and structural information of molecules. One of the weaknesses of x-ray absorption is its sensitivity to all of the atoms of a particular element in a sample. Through out this thesis, a new technique for enhancing the site- and spin-selectivity of the x-ray absorption has been developed. By high resolution fluorescence detection, the chemical sensitivity of K emission spectra can be used to identify oxidation and spin states; it can also be used to facilitate site-selective X-ray Absorption Near Edge Structure (XANES) and site-selective Extended X-ray Absorption Fine Structure (EXAFS). The spin polarization in K fluorescence could be used to generate spin selective XANES or spin-polarized EXAFS, which provides a new measure of the spin density, or the nature of magnetic neighboring atoms. Finally, dramatic line-sharpening effects by the combination of absorption and emission processes allow observation of structure that is normally unobservable. All these unique characters can enormously simplify a complex x-ray spectrum. Applications of this novel technique have generated information from various transition-metal model compounds to metalloproteins. The absorption and emission spectra by high resolution fluorescence detection are interdependent. The ligand field multiplet model has been used for the analysis of Kα and Kβ emission spectra. First demonstration on different chemical states of Fe compounds has shown the applicability of site selectivity and spin polarization. Different interatomic distances of the same element in different chemical forms have been detected using site-selective EXAFS

  7. Spin injection and detection in lanthanum- and niobium-doped SrTiO3 using the Hanle technique

    KAUST Repository

    Han, Wei

    2013-07-08

    There has been much interest in the injection and detection of spin-polarized carriers in semiconductors for the purposes of developing novel spintronic devices. Here we report the electrical injection and detection of spin-polarized carriers into Nb-doped strontium titanate single crystals and La-doped strontium titanate epitaxial thin films using MgO tunnel barriers and the three-terminal Hanle technique. Spin lifetimes of up to ∼100 ps are measured at room temperature and vary little as the temperature is decreased to low temperatures. However, the mobility of the strontium titanate has a strong temperature dependence. This behaviour and the carrier doping dependence of the spin lifetime suggest that the spin lifetime is limited by spin-dependent scattering at the MgO/strontium titanate interfaces, perhaps related to the formation of doping induced Ti 3+. Our results reveal a severe limitation of the three-terminal Hanle technique for measuring spin lifetimes within the interior of the subject material. © 2013 Macmillan Publishers Limited. All rights reserved.

  8. Muon spin rotation study of the topological superconductor SrxBi2Se3

    Science.gov (United States)

    Leng, H.; Cherian, D.; Huang, Y. K.; Orain, J.-C.; Amato, A.; de Visser, A.

    2018-02-01

    We report transverse-field (TF) muon spin rotation experiments on single crystals of the topological superconductor SrxBi2Se3 with nominal concentrations x =0.15 and 0.18 (Tc˜3 K). The TF spectra (B =10 mT), measured after cooling to below Tc in field, did not show any additional damping of the muon precession signal due to the flux line lattice within the experimental uncertainty. This puts a lower bound on the magnetic penetration depth λ ≥2.3 μ m . However, when we induce disorder in the vortex lattice by changing the magnetic field below Tc, a sizable damping rate is obtained for T →0 . The data provide microscopic evidence for a superconducting volume fraction of ˜70 % in the x =0.18 crystal and thus bulk superconductivity.

  9. Adiabatic quantum computing with spin qubits hosted by molecules.

    Science.gov (United States)

    Yamamoto, Satoru; Nakazawa, Shigeaki; Sugisaki, Kenji; Sato, Kazunobu; Toyota, Kazuo; Shiomi, Daisuke; Takui, Takeji

    2015-01-28

    A molecular spin quantum computer (MSQC) requires electron spin qubits, which pulse-based electron spin/magnetic resonance (ESR/MR) techniques can afford to manipulate for implementing quantum gate operations in open shell molecular entities. Importantly, nuclear spins, which are topologically connected, particularly in organic molecular spin systems, are client qubits, while electron spins play a role of bus qubits. Here, we introduce the implementation for an adiabatic quantum algorithm, suggesting the possible utilization of molecular spins with optimized spin structures for MSQCs. We exemplify the utilization of an adiabatic factorization problem of 21, compared with the corresponding nuclear magnetic resonance (NMR) case. Two molecular spins are selected: one is a molecular spin composed of three exchange-coupled electrons as electron-only qubits and the other an electron-bus qubit with two client nuclear spin qubits. Their electronic spin structures are well characterized in terms of the quantum mechanical behaviour in the spin Hamiltonian. The implementation of adiabatic quantum computing/computation (AQC) has, for the first time, been achieved by establishing ESR/MR pulse sequences for effective spin Hamiltonians in a fully controlled manner of spin manipulation. The conquered pulse sequences have been compared with the NMR experiments and shown much faster CPU times corresponding to the interaction strength between the spins. Significant differences are shown in rotational operations and pulse intervals for ESR/MR operations. As a result, we suggest the advantages and possible utilization of the time-evolution based AQC approach for molecular spin quantum computers and molecular spin quantum simulators underlain by sophisticated ESR/MR pulsed spin technology.

  10. BROOKHAVEN: Spin rotator to boost polarization

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    The Alternating Gradient Synchrotron (AGS) at Brookhaven holds the world record energy for spin polarized proton beams at 22 GeV. However this required a complicated two-week commissioning effort to overcome 39 imperfection depolarizing resonances and six intrinsic depolarizing resonances

  11. A technique for measurement of vector and tensor polarization in solid spin one polarized targets

    International Nuclear Information System (INIS)

    Kielhorn, W.F.

    1991-06-01

    Vector and tensor polarizations are explicitly defined and used to characterize the polarization states of spin one polarized targets, and a technique for extracting these polarizations from nuclear magnetic resonance (NMR) data is developed. This technique is independent of assumptions about spin temperature, but assumes the target's crystal structure induces a quadrupole interaction with the spin one particles. Analysis of the NMR signals involves a computer curve fitting algorithm implemented with a fast Fourier transform method which speeds and simplifies curve fitting algorithms used previously. For accurate curve fitting, the NMR electronic circuit must be modeled by the fitting algorithm. Details of a circuit, its model, and data collected from this circuit are given for a solid deuterated ammonia target. 37 refs., 19 figs., 3 tabs

  12. Developing an Asteroid Rotational Theory

    Science.gov (United States)

    Geis, Gena; Williams, Miguel; Linder, Tyler; Pakey, Donald

    2018-01-01

    The goal of this project is to develop a theoretical asteroid rotational theory from first principles. Starting at first principles provides a firm foundation for computer simulations which can be used to analyze multiple variables at once such as size, rotation period, tensile strength, and density. The initial theory will be presented along with early models of applying the theory to the asteroid population. Early results confirm previous work by Pravec et al. (2002) that show the majority of the asteroids larger than 200m have negligible tensile strength and have spin rates close to their critical breakup point. Additionally, results show that an object with zero tensile strength has a maximum rotational rate determined by the object’s density, not size. Therefore, an iron asteroid with a density of 8000 kg/m^3 would have a minimum spin period of 1.16h if the only forces were gravitational and centrifugal. The short-term goal is to include material forces in the simulations to determine what tensile strength will allow the high spin rates of asteroids smaller than 150m.

  13. NMR system and method having a permanent magnet providing a rotating magnetic field

    Science.gov (United States)

    Schlueter, Ross D [Berkeley, CA; Budinger, Thomas F [Berkeley, CA

    2009-05-19

    Disclosed herein are systems and methods for generating a rotating magnetic field. The rotating magnetic field can be used to obtain rotating-field NMR spectra, such as magic angle spinning spectra, without having to physically rotate the sample. This result allows magic angle spinning NMR to be conducted on biological samples such as live animals, including humans.

  14. Quantum rings in magnetic fields and spin current generation.

    Science.gov (United States)

    Cini, Michele; Bellucci, Stefano

    2014-04-09

    We propose three different mechanisms for pumping spin-polarized currents in a ballistic circuit using a time-dependent magnetic field acting on an asymmetrically connected quantum ring at half filling. The first mechanism works thanks to a rotating magnetic field and produces an alternating current with a partial spin polarization. The second mechanism works by rotating the ring in a constant field; like the former case, it produces an alternating charge current, but the spin current is dc. Both methods do not require a spin-orbit interaction to achieve the polarized current, but the rotating ring could be used to measure the spin-orbit interaction in the ring using characteristic oscillations. On the other hand, the last mechanism that we propose depends on the spin-orbit interaction in an essential way, and requires a time-dependent magnetic field in the plane of the ring. This arrangement can be designed to pump a purely spin current. The absence of a charge current is demonstrated analytically. Moreover, a simple formula for the current is derived and compared with the numerical results.

  15. Nuclear spin conversion in formaldehyde

    OpenAIRE

    Chapovsky, Pavel L.

    2000-01-01

    Theoretical model of the nuclear spin conversion in formaldehyde (H2CO) has been developed. The conversion is governed by the intramolecular spin-rotation mixing of molecular ortho and para states. The rate of conversion has been found equal 1.4*10^{-4}~1/s*Torr. Temperature dependence of the spin conversion has been predicted to be weak in the wide temperature range T=200-900 K.

  16. Imaging of propagation dynamics of optically-excited spin waves in a garnet film

    International Nuclear Information System (INIS)

    Hashimoto, Yusuke; Saitoh, Eiji

    2016-01-01

    We demonstrate the direct imaging of the propagation dynamics of the optically-excited spin waves in a garnet film observed with an all-optical pump-and-probe magneto-optical imaging technique having sub-pico second time-resolution, sub-micrometer spatial resolution, and milli-degrees of accuracy in the rotation angle of the light polarization. (author)

  17. New spoiled spin-echo technique for three-dimensional MR imaging

    International Nuclear Information System (INIS)

    Darrasse, L.; Mao, L.; Saint-Jalmes, H.

    1989-01-01

    For 3D MR imaging within a convenient scanning time, the authors propose an improved spin-echo technique that permits the use of TRs shorter than 100 msec. They use a two-pulse RF sequence (α-π echo). The echo is read with conventional 3DFT encoding. To avoid steady-state signal refocusing before either α or (imperfect) π pulses, we apply randomized gradient spoilers both before each α pulse and on each side of the π pulse. So the sequence works like standard spin- echo sequences, with the z-magnetization recovery being adjusted by means of α rather than TR. The authors have investigated the method on a new 0.1-T Magnetom system dedicated for 3D MR imaging

  18. The Spin Vector of (832) Karin

    Science.gov (United States)

    Slivan, Stephen M.; Molnar, L. A.

    2010-10-01

    We observed rotation lightcurves of Koronis family and Karin cluster member (832) Karin during its four consecutive apparitions in 2006-2009, and combined the new observations with previously published lightcurves to determine its spin vector orientation and preliminary model shape. Karin is a prograde rotator with a period of 18.352 h, spin obliquity near 41°, and pole ecliptic longitude near either 51° or 228°. Although the two ambiguous pole solutions are near the clustered pole solutions of four Koronis family members whose spins are thought to be trapped in a spin-orbit resonance (Vokrouhlický et al., 2003), Karin does not seem to be trapped in the resonance; this is consistent with the expectation that the 6 My age of Karin (Nesvorný et al., 2002) is too young for YORP torques to have modified its spin since its formation. The spin vector and shape results for Karin will constrain family formation models that include spin properties, and we discuss the Karin results in the context of the other members of the Karin cluster, the Karin parent body, and the parent body's siblings in the Koronis family.

  19. Innovative Measurement Diagnostics for Analysis of Jet Interactions in Rotating Flowfields; TOPICAL

    International Nuclear Information System (INIS)

    AMATUCCI, VINCENT A.; BERESH, STEVEN J.; HENFLING, JOHN F.; ERVEN, ROCKY J.; BOURDON, CHRIS J.

    2002-01-01

    baseline non-rotating experiments to validate the durability of the technologies and techniques. The program successfully investigated a wide variety of instrumentation and experimental techniques and ended with basic experiments for a non-rotating model with jet-on with the onboard jets operating and both rotating and non-rotating model conditions

  20. Quantum dynamics of nuclear spins and spin relaxation in organic semiconductors

    Science.gov (United States)

    Mkhitaryan, V. V.; Dobrovitski, V. V.

    2017-06-01

    We investigate the role of the nuclear-spin quantum dynamics in hyperfine-induced spin relaxation of hopping carriers in organic semiconductors. The fast-hopping regime, when the carrier spin does not rotate much between subsequent hops, is typical for organic semiconductors possessing long spin coherence times. We consider this regime and focus on a carrier random-walk diffusion in one dimension, where the effect of the nuclear-spin dynamics is expected to be the strongest. Exact numerical simulations of spin systems with up to 25 nuclear spins are performed using the Suzuki-Trotter decomposition of the evolution operator. Larger nuclear-spin systems are modeled utilizing the spin-coherent state P -representation approach developed earlier. We find that the nuclear-spin dynamics strongly influences the carrier spin relaxation at long times. If the random walk is restricted to a small area, it leads to the quenching of carrier spin polarization at a nonzero value at long times. If the random walk is unrestricted, the carrier spin polarization acquires a long-time tail, decaying as 1 /√{t } . Based on the numerical results, we devise a simple formula describing the effect quantitatively.

  1. Arthroscopic Double-Row Transosseous Equivalent Rotator Cuff Repair with a Knotless Self-Reinforcing Technique

    OpenAIRE

    Mook, William R.; Greenspoon, Joshua A.; Millett, Peter J.

    2016-01-01

    Background: Rotator cuff tears are a significant cause of shoulder morbidity. Surgical techniques for repair have evolved to optimize the biologic and mechanical variables critical to tendon healing. Double-row repairs have demonstrated superior biomechanical advantages to a single-row. Methods: The preferred technique for rotator cuff repair of the senior author was reviewed and described in a step by step fashion. The final construct is a knotless double row transosseous equivalent construc...

  2. Constraints on Spin Axis and Thermal Properties of Asteroids in the WISE Catalog

    Science.gov (United States)

    MacLennan, Eric M.; Emery, J. P.

    2013-10-01

    It has widely been accepted that dynamical state of asteroids can strongly be influenced by radiation forces (e.g., Yarkovsky and YORP). Determination of an object’s thermal properties and spin state are a critical step towards understanding the effects of these forces. In this respect, observations of thermal flux emitted from the surfaces of asteroids are a powerful tool. The emission of flux is determined by the temperature distribution which is controlled by the thermal inertia, rotation rate, and spin axis orientation. By gathering data at multiple viewing geometries, the temperature distribution can be modeled accurately enough to separate the effects attributed to (some of) these parameters. Over the length of its mission, the Wide-Field Infrared Survey Explorer (WISE) observed many asteroids in two epochs (i.e., on either side of opposition) such that data for both morning and afternoon times were gathered. We have begun a project that employs a Thermophysical Model (TPM) in order to analyze these multi-epoch thermal observations with the goal of deriving the thermal properties and spin axis of a large number of asteroids. Here, we first investigate the validity and limits of our method on objects with a previously determined spin axis. Asteroid (413) Edburga has a published spin axis of λ = 202o, β = - 45o (ecliptic longitude and latitude, respectively) using the lightcurve inversion method. With our technique, we estimate a solution consistent with the previous estimate. Applying our TPM to WISE multi-epoch thermal observations of (155) Scylla (no known spin axis estimate), we also place estimates for the ecliptic longitude and latitude of its spin axis. Analysis of multi-epoch thermal data enables determination of spin axis orientation without knowing the rotation period, in contrast to the lightcurve inversion method. This is due to the coupling of thermal inertia and rotation rate in determining the longitudinal distribution of temperature. Their

  3. Is the arthroscopic suture bridge technique suitable for full-thickness rotator cuff tears of any size?

    Science.gov (United States)

    Lee, Sung Hyun; Kim, Jeong Woo; Kim, Tae Kyun; Kweon, Seok Hyun; Kang, Hong Je; Kim, Se Jin; Park, Jin Sung

    2017-07-01

    The purpose of this study was to compare functional outcomes and tendon integrity between the suture bridge and modified tension band techniques for arthroscopic rotator cuff repair. A consecutive series of 128 patients who underwent the modified tension band (MTB group; 69 patients) and suture bridge (SB group; 59 patients) techniques were enrolled. The pain visual analogue scale (VAS), Constant, and American Shoulder and Elbow Surgeons (ASES) scores were determined preoperatively and at the final follow-up. Rotator cuff hypotrophy was quantified by calculating the occupation ratio (OR). Rotator cuff integrity and the global fatty degeneration index were determined by using magnetic resonance imaging at 6 months postoperatively. The average VAS, Constant, and ASES scores improved significantly at the final follow-up in both groups (p bridge groups (7.0 vs. 6.8%, respectively; p = n.s.). The retear rate of large-to-massive tears was significantly lower in the suture bridge group than in the modified tension band group (33.3 vs. 70%; p = 0.035). Fatty infiltration (postoperative global fatty degeneration index, p = 0.022) and muscle hypotrophy (postoperative OR, p = 0.038) outcomes were significantly better with the suture bridge technique. The retear rate was lower with the suture bridge technique in the case of large-to-massive rotator cuff tears. Additionally, significant improvements in hypotrophy and fatty infiltration of the rotator cuff were obtained with the suture bridge technique, possibly resulting in better anatomical outcomes. The suture bridge technique was a more effective method for the repair of rotator cuff tears of all sizes as compared to the modified tension band technique. Retrospective Cohort Design, Treatment Study, level III.

  4. A technique for measurement of vector and tensor polarization in solid spin one polarized targets

    Energy Technology Data Exchange (ETDEWEB)

    Kielhorn, W.F.

    1991-06-01

    Vector and tensor polarizations are explicitly defined and used to characterize the polarization states of spin one polarized targets, and a technique for extracting these polarizations from nuclear magnetic resonance (NMR) data is developed. This technique is independent of assumptions about spin temperature, but assumes the target's crystal structure induces a quadrupole interaction with the spin one particles. Analysis of the NMR signals involves a computer curve fitting algorithm implemented with a fast Fourier transform method which speeds and simplifies curve fitting algorithms used previously. For accurate curve fitting, the NMR electronic circuit must be modeled by the fitting algorithm. Details of a circuit, its model, and data collected from this circuit are given for a solid deuterated ammonia target. 37 refs., 19 figs., 3 tabs.

  5. Gel spinning of silk tubes for tissue engineering

    Science.gov (United States)

    Lovett, Michael; Cannizzaro, Christopher; Vunjak-Novakovic, Gordana; Kaplan, David L.

    2011-01-01

    Tubular vessels for tissue engineering are typically fabricated using a molding, dipping, or electrospinning technique. While these techniques provide some control over inner and outer diameters of the tube, they lack the ability to align the polymers or fibers of interest throughout the tube. This is an important aspect of biomaterial composite structure and function for mechanical and biological impact of tissue outcomes. We present a novel aqueous process system to spin tubes from biopolymers and proteins such as silk fibroin. Using silk as an example, this method of winding an aqueous solution around a reciprocating rotating mandrel offers substantial improvement in the control of the tube properties, specifically with regard to winding pattern, tube porosity, and composite features. Silk tube properties are further controlled via different post-spinning processing mechanisms such as methanol-treatment, air-drying, and lyophilization. This approach to tubular scaffold manufacture offers numerous tissue engineering applications such as complex composite biomaterial matrices, blood vessel grafts and nerve guides, among others. PMID:18801570

  6. Relativistic motion of spinning particles in a gravitational field

    International Nuclear Information System (INIS)

    Chicone, C.; Mashhoon, B.; Punsly, B.

    2005-01-01

    The relative motion of a classical relativistic spinning test particle is studied with respect to a nearby free test particle in the gravitational field of a rotating source. The effects of the spin-curvature coupling force are elucidated and the implications of the results for the motion of rotating plasma clumps in astrophysical jets are discussed

  7. Interfacial spin-orbit splitting and current-driven spin torque in anisotropic tunnel junctions

    KAUST Repository

    Manchon, Aurelien

    2011-05-17

    Spin transport in magnetic tunnel junctions comprising a single magnetic layer in the presence of interfacial spin-orbit interaction (SOI) is investigated theoretically. Due to the presence of interfacial SOI, a current-driven spin torque can be generated at the second order in SOI, even in the absence of an external spin polarizer. This torque possesses two components, one in plane and one perpendicular to the plane of rotation, that can induce either current-driven magnetization switching from an in-plane to out-of-plane configuration or magnetization precessions, similar to spin transfer torque in spin valves. Consequently, it appears that it is possible to control the magnetization steady state and dynamics by either varying the bias voltage or electrically modifying the SOI at the interface.

  8. Determination of proton-nucleon analyzing powers and spin-rotation-depolarization parameters at 500 MeV

    International Nuclear Information System (INIS)

    Marshall, J.A.; Barlett, M.L.; Fergerson, R.W.; Hoffmann, G.W.; Milner, E.C.; Ray, L.; Amann, J.F.; Bonner, B.E.; McClelland, J.B.

    1986-01-01

    500 MeV p-arrow-right+p elastic and quasielastic, and p-arrow-right+n quasielastic, analyzing powers (A/sub y/) and spin-rotation-depolarization parameters (D/sub S//sub S/, D/sub S//sub L/, D/sub L//sub S/, D/sub L//sub L/, D/sub N//sub N/) were determined for center-of-momentum angular ranges 6.8 0 -55.4 0 (elastic) and 22.4 0 -55.4 0 (quasielastic); liquid hydrogen and deuterium targets were used. The p-arrow-right+p elastic and quasielastic results are in good agreement; both the p-arrow-right+p and p-arrow-right+n parameters are well described by current phase shift solutions

  9. Bias Dependent Spin Relaxation in a [110]-InAs/AlSb Two Dimensional Electron System

    Science.gov (United States)

    Hicks, J.; Holabird, K.

    2005-03-01

    Manipulation of electron spin is a critical component of many proposed semiconductor spintronic devices. One promising approach utilizes the Rashba effect by which an applied electric field can be used to reduce the spin lifetime or rotate spin orientation through spin-orbit interaction. The large spin-orbit interaction needed for this technique to be effective typically leads to fast spin relaxation through precessional decay, which may severely limit device architectures and functionalities. An exception arises in [110]-oriented heterostructures where the crystal magnetic field associated with bulk inversion asymmetry lies along the growth direction and in which case spins oriented along the growth direction do not precess. These considerations have led to a recent proposal of a spin-FET that incorporates a [110]-oriented, gate-controlled InAs quantum well channel [1]. We report measurements of the electron spin lifetime as a function of applied electric field in a [110]-InAs 2DES. Measurements made using an ultrafast, mid-IR pump-probe technique indicate that the spin lifetime can be reduced from its maximum to minimum value over a range of less than 0.2V per quantum well at room temperature. This work is supported by DARPA, NSERC and the NSF grant ECS - 0322021. [1] K. C. Hall, W. H. Lau, K. Gundogdu, M. E. Flatte, and T. F. Boggess, Appl. Phys. Lett. 83, 2937 (2003).

  10. Long-lived nanosecond spin coherence in high-mobility 2DEGs confined in double and triple quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Ullah, S.; Gusev, G. M.; Hernandez, F. G. G., E-mail: felixggh@if.usp.br [Instituto de Física, Universidade de São Paulo, Caixa Postal 66318, CEP 05315-970 São Paulo, SP (Brazil); Bakarov, A. K. [Institute of Semiconductor Physics and Novosibirsk State University, Novosibirsk 630090 (Russian Federation)

    2016-06-07

    We investigated the spin coherence of high-mobility two-dimensional electron gases confined in multilayer GaAs quantum wells. The dynamics of the spin polarization was optically studied using pump-probe techniques: time-resolved Kerr rotation and resonant spin amplification. For double and triple quantum wells doped beyond the metal-to-insulator transition, the spin-orbit interaction was tailored by the sample parameters of structural symmetry (Rashba constant), width, and electron density (Dresselhaus linear and cubic constants) which allow us to attain long dephasing times in the nanoseconds range. The determination of the scales, namely, transport scattering time, single-electron scattering time, electron-electron scattering time, and spin polarization decay time further supports the possibility of using n-doped multilayer systems for developing spintronic devices.

  11. High spin rotational bands in Zn

    Indian Academy of Sciences (India)

    We present here some preliminary results from our studies in the. ~ ¼ region in which we have observed an yrast band structure in Zn extending to spin (41/2 ). ... gaps implies that nuclei may exhibit different shapes at different excitation energies. .... uration, identifying previously unobserved states up to an excitation energy ...

  12. Angular dependence of the disorder crossover in the vortex lattice of Bi2.15Sr1.85CaCu2O8+δ by muon spin rotation and torque magnetometry

    International Nuclear Information System (INIS)

    Aegerter, C.M.; Hofer, J.; Savic, I.M.; Keller, H.; Lee, S.L.; Ager, C.; Lloyd, S.H.; Forgan, E.M.

    1998-01-01

    Using the techniques of muon spin rotation and torque magnetometry, we investigate the crossover field B cr in Bi 2.15 Sr 1.85 Ca 1 Cu 2 O 8+δ at which the vortex lattice becomes disordered along the field direction. It is found that B cr scales as the projection of the applied field along the perpendicular to the superconducting planes. This has the implication that a field large enough to give a disordered lattice when applied perpendicular to the planes, can give a well-ordered vortex-line lattice for angles of the field to the c axis greater than a critical value. copyright 1998 The American Physical Society

  13. Macroscopic spin-orbit coupling in non-uniform magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Tabat, N.; Edelman, H. S.; Song, D. [Semaphore Scientific, Inc., St. Cloud, Minnesota 56301 (United States); Vogt, T. [Department of Electrical and Computer Engineering, St. Cloud State University, St. Cloud, Minnesota 56301 (United States)

    2015-03-02

    Translational dynamics of aggregated magnetic nano-particles placed in a rotating external magnetic field is described. It is observed and explained that aggregates that spin within a radially decreasing field strength must execute an orbital motion of their center of mass in a sense that counters their spin rotation. This orbital motion is tightly coupled to the spin dynamics of the aggregates. An analytical model for the canonical variables describing the orbital motion is derived and shown to be in good agreement with the measured values.

  14. Macroscopic spin-orbit coupling in non-uniform magnetic fields

    International Nuclear Information System (INIS)

    Tabat, N.; Edelman, H. S.; Song, D.; Vogt, T.

    2015-01-01

    Translational dynamics of aggregated magnetic nano-particles placed in a rotating external magnetic field is described. It is observed and explained that aggregates that spin within a radially decreasing field strength must execute an orbital motion of their center of mass in a sense that counters their spin rotation. This orbital motion is tightly coupled to the spin dynamics of the aggregates. An analytical model for the canonical variables describing the orbital motion is derived and shown to be in good agreement with the measured values

  15. Counter-rotating standing spin waves: A magneto-optical illusion

    Science.gov (United States)

    Shihab, S.; Thevenard, L.; Lemaître, A.; Gourdon, C.

    2017-04-01

    We excite perpendicular standing spin waves by a laser pulse in a GaMnAsP ferromagnetic layer and detect them using time-resolved magneto-optical effects. Quite counterintuitively, we find the first two excited modes to be of opposite chirality. We show that this can only be explained by taking into account absorption and optical phase shift inside the layer. This optical illusion is particularly strong in weakly absorbing layers. These results provide a correct identification of spin waves modes, enabling a trustworthy estimation of their respective weight as well as an unambiguous determination of the spin stiffness parameter.

  16. FITTING HELICAL SNAKE AND ROTATOR FIELD STRENGTH MEASUREMENTS IN RHIC

    International Nuclear Information System (INIS)

    RANJBAR, V.; LUCCIO, A.U.; MACKAY, W.W.; TSOUPAS, N.

    2001-01-01

    We examined recent multi-pole measurements for the helical snakes and rotators in RHIC to generate a full field map. Since multi-pole measurements yield real field values for B, field components we developed a unique technique to evaluate the full fields using a traditional finite element analysis software [1]. From these measurements we employed SNIG [2] to generate orbit and Spin plots. From orbit values we generated a transfer matrix for the first snake

  17. Developing lignin-based bio-nanofibers by centrifugal spinning technique.

    Science.gov (United States)

    Stojanovska, Elena; Kurtulus, Mustafa; Abdelgawad, Abdelrahman; Candan, Zeki; Kilic, Ali

    2018-07-01

    Lignin-based nanofibers were produced via centrifugal spinning from lignin-thermoplastic polyurethane polymer blends. The most suitable process parameters were chosen by optimization of the rotational speed, nozzle diameter and spinneret-to-collector distance using different blend ratios of the two polymers at different total polymer concentrations. The basic characteristics of polymer solutions were enlightened by their viscosity and surface tension. The morphology of the fibers produced was characterized by SEM, while their thermal properties by DSC and TG analysis. Multiply regression was used to determine the parameters that have higher impact on the fiber diameter. It was possible to obtain thermally stable lignin/polyurethane nanofibers with diameters below 500nm. From the aspect of spinnability, 1:1 lignin/TPU contents were shown to be more feasible. On the other side, the most suitable processing parameters were found to be angular velocity of 8500rpm for nozzles of 0.5mm diameter and working distance of 30cm. Copyright © 2018 Elsevier B.V. All rights reserved.

  18. Self-gravitating axially symmetric disks in general-relativistic rotation

    Science.gov (United States)

    Karkowski, Janusz; Kulczycki, Wojciech; Mach, Patryk; Malec, Edward; Odrzywołek, Andrzej; Piróg, Michał

    2018-05-01

    We integrate numerically axially symmetric stationary Einstein equations describing self-gravitating disks around spinless black holes. The numerical scheme is based on a method developed by Shibata, but contains important new ingredients. We derive a new general-relativistic Keplerian rotation law for self-gravitating disks around spinning black holes. Former results concerning rotation around spinless black holes emerge in the limit of a vanishing spin parameter. These rotation curves might be used for the description of rotating stars, after appropriate modification around the symmetry axis. They can be applied to the description of compact torus-black hole configurations, including active galactic nuclei or products of coalescences of two neutron stars.

  19. A brief review of intruder rotational bands and magnetic rotation in the A = 110 mass region

    Science.gov (United States)

    Banerjee, P.

    2018-05-01

    Nuclei in the A ∼ 110 mass region exhibit interesting structural features. One of these relates to the process by which specific configurations, built on the excitation of one or more protons across the Z = 50 shell-gap, manifest as collective rotational bands at intermediate spins and gradually lose their collectivity with increase in spin and terminate in a non-collective state at the maximum spin which the configuration can support. These bands are called terminating bands that co-exist with spherical states. Some of these bands are said to terminate smoothly underlining the continuous character of the process by which the band evolves from significant collectivity at low spin to a pure particle-hole non-collective state at the highest spin. The neutron-deficient A ∼ 110 mass region provides the best examples of smoothly terminating bands. The present experimental and theoretical status of such bands in several nuclei with 48 ≤ Z ≤ 52 spanning the 106 ≤ A ≤ 119 mass region have been reviewed in this article. The other noteworthy feature of nuclei in the A ∼ 110 mass region is the observation of regular rotation-like sequences of strongly enhanced magnetic dipole transitions in near-spherical nuclei. These bands, unlike the well-studied rotational sequences in deformed nuclei, arise from a spontaneous symmetry breaking by the anisotropic currents of a few high-j excited particles and holes. This mode of excitation is called magnetic rotation and was first reported in the Pb region. Evidence in favor of the existence of such structures, also called shears bands, are reported in the literature for a large number of Cd, In, Sn and Sb isotope with A ∼ 110. The present article provides a general overview of these reported structures across this mass region. The review also discusses antimagnetic rotation bands and a few cases of octupole correlations in the A = 110 mass region.

  20. Studies of LENRA-Toughened PVC non-woven membranes prepared by electro spinning technique

    International Nuclear Information System (INIS)

    Dahlan Mohd; Mahathir Mohamed; Khirul Hafiz mohd Yusof

    2010-01-01

    Lately research in use of so-called green chemicals draws strong interest from research community due to the climate change issues. Malaysia is in strong position to take this advantage because we are among the world biggest producers of natural rubber and palm oil - the two sources of important green renewable chemical feedstock in the near future. For the last couple of years we have shown how modified natural rubbers especially liquid natural rubber and its derivatives such as liquid epoxidized natural rubber acrylate (LENRA) could be used in various applications via among others sol-gel technique and radiation curing technology. This time around we will show another application on how non-woven membranes made from PVC can be prepared by electro spinning technique using radiation curable LENRA as toughener. The electro spinning technique has great potential in producing nano fiber materials to be used in various applications to ensure sustainable energy and environments for the future. (author)

  1. Spin Transport in Nondegenerate Si with a Spin MOSFET Structure at Room Temperature

    Science.gov (United States)

    Sasaki, Tomoyuki; Ando, Yuichiro; Kameno, Makoto; Tahara, Takayuki; Koike, Hayato; Oikawa, Tohru; Suzuki, Toshio; Shiraishi, Masashi

    2014-09-01

    Spin transport in nondegenerate semiconductors is expected to pave the way to the creation of spin transistors, spin logic devices, and reconfigurable logic circuits, because room-temperature (RT) spin transport in Si has already been achieved. However, RT spin transport has been limited to degenerate Si, which makes it difficult to produce spin-based signals because a gate electric field cannot be used to manipulate such signals. Here, we report the experimental demonstration of spin transport in nondegenerate Si with a spin metal-oxide-semiconductor field-effect transistor (MOSFET) structure. We successfully observe the modulation of the Hanle-type spin-precession signals, which is a characteristic spin dynamics in nondegenerate semiconductors. We obtain long spin transport of more than 20 μm and spin rotation greater than 4π at RT. We also observe gate-induced modulation of spin-transport signals at RT. The modulation of the spin diffusion length as a function of a gate voltage is successfully observed, which we attribute to the Elliott-Yafet spin relaxation mechanism. These achievements are expected to lead to the creation of practical Si-based spin MOSFETs.

  2. Rotating fluid models in classical and quantum mechanics

    International Nuclear Information System (INIS)

    Arvieu, R.; Troudet, T.

    1979-01-01

    To describe the behavior of high-spin nuclei it is necessary to refer back to the classical mechanics of fluids in rotation where some results are general enough to apply to the rotational nuclear fluid. It is then shown that the quantum model of rotational oscillator gives a simple classification of rotating configurations [fr

  3. The ideal relativistic rotating gas as a perfect fluid with spin

    International Nuclear Information System (INIS)

    Becattini, F.; Tinti, L.

    2010-01-01

    We show that the ideal relativistic spinning gas at complete thermodynamical equilibrium is a fluid with a non-vanishing spin density tensor σ μν . After having obtained the expression of the local spin-dependent phase-space density f(x, p) στ in the Boltzmann approximation, we derive the spin density tensor and show that it is proportional to the acceleration tensor Ω μν constructed with the Frenet-Serret tetrad. We recover the proper generalization of the fundamental thermodynamical relation, involving an additional term -(1/2)Ω μν σ μν . We also show that the spin density tensor has a non-vanishing projection onto the four-velocity field, i.e. t μ = σ μν u ν ≠ 0, in contrast to the common assumption t μ = 0, known as Frenkel condition, in the thus-far proposed theories of relativistic fluids with spin. We briefly address the viewpoint of the accelerated observer and inertial spin effects.

  4. Magnetic interactions in strongly correlated systems: Spin and orbital contributions

    Energy Technology Data Exchange (ETDEWEB)

    Secchi, A., E-mail: a.secchi@science.ru.nl [Radboud University, Institute for Molecules and Materials, 6525 AJ Nijmegen (Netherlands); Lichtenstein, A.I. [Universitat Hamburg, Institut für Theoretische Physik, Jungiusstraße 9, D-20355 Hamburg (Germany); Katsnelson, M.I. [Radboud University, Institute for Molecules and Materials, 6525 AJ Nijmegen (Netherlands)

    2015-09-15

    We present a technique to map an electronic model with local interactions (a generalized multi-orbital Hubbard model) onto an effective model of interacting classical spins, by requiring that the thermodynamic potentials associated to spin rotations in the two systems are equivalent up to second order in the rotation angles, when the electronic system is in a symmetry-broken phase. This allows to determine the parameters of relativistic and non-relativistic magnetic interactions in the effective spin model in terms of equilibrium Green’s functions of the electronic model. The Hamiltonian of the electronic system includes, in addition to the non-relativistic part, relativistic single-particle terms such as the Zeeman coupling to an external magnetic field, spin–orbit coupling, and arbitrary magnetic anisotropies; the orbital degrees of freedom of the electrons are explicitly taken into account. We determine the complete relativistic exchange tensors, accounting for anisotropic exchange, Dzyaloshinskii–Moriya interactions, as well as additional non-diagonal symmetric terms (which may include dipole–dipole interaction). The expressions of all these magnetic interactions are determined in a unified framework, including previously disregarded features such as the vertices of two-particle Green’s functions and non-local self-energies. We do not assume any smallness in spin–orbit coupling, so our treatment is in this sense exact. Finally, we show how to distinguish and address separately the spin, orbital and spin–orbital contributions to magnetism, providing expressions that can be computed within a tight-binding Dynamical Mean Field Theory.

  5. Black hole spin from wobbling and rotation of the M87 jet and a sign of a magnetically arrested disc

    Science.gov (United States)

    Sob'yanin, Denis Nikolaevich

    2018-06-01

    New long-term Very Long Baseline Array observations of the well-known jet in the M87 radio galaxy at 43 GHz show that the jet experiences a sideways shift with an approximately 8-10 yr quasi-periodicity. Such jet wobbling can be indicative of a relativistic Lense-Thirring precession resulting from a tilted accretion disc. The wobbling period together with up-to-date kinematic data on jet rotation opens up the possibility for estimating angular momentum of the central supermassive black hole. In the case of a test-particle precession, the specific angular momentum is J/Mc = (2.7 ± 1.5) × 1014 cm, implying moderate dimensionless spin parameters a = 0.5 ± 0.3 and 0.31 ± 0.17 for controversial gas-dynamic and stellar-dynamic black hole masses. However, in the case of a solid-body-like precession, the spin parameter is much smaller for both masses, 0.15 ± 0.05. Rejecting this value on the basis of other independent spin estimations requires the existence of a magnetically arrested disc in M87.

  6. Nuclear magnetic resonance in solids: evolution of spin temperature under multipulse irradiation and high symmetry molecular motions

    International Nuclear Information System (INIS)

    Quiroga, Luis

    1982-01-01

    In a first part, autocorrelation functions are calculated taking into account the symmetry of molecular motions by group theoretical techniques. This very general calculation method is then used to evaluate the NMR spin-lattice relaxation times T 1 and T 1 p as a function of the relative orientations of the magnetic field, the crystal and the rotation axis, in particular for cyclic, dihedral and cubic groups. Models of molecular reorientations such as jumps between a finite number of allowed orientations, rotational diffusion and superimposed reorientations are all investigated with the same formalism. In part two, the effect of the coherent excitation of spins, by multipulse sequences of the WHH-4 type, on the evolution of the heat capacity and spin temperature of the dipolar reservoir is analysed. It is shown both theoretically and experimentally that adiabatic (reversible) reduction of the dipolar Hamiltonian and its spin temperature is obtained when the amplitude of pulses (rotation angle) is slowly raised. The sudden switching on and off of the HW-8 sequence is then shown to lead to the same reversible reduction in a shorter time. It is also shown that, by this way, sensibility and selectivity of double resonance measurements of weak gyromagnetic ratio nuclei are strongly increased. This is experimentally illustrated in some cases. (author) [fr

  7. Spin precession and spin waves in a chiral electron gas: Beyond Larmor's theorem

    Science.gov (United States)

    Karimi, Shahrzad; Baboux, Florent; Perez, Florent; Ullrich, Carsten A.; Karczewski, Grzegorz; Wojtowicz, Tomasz

    2017-07-01

    Larmor's theorem holds for magnetic systems that are invariant under spin rotation. In the presence of spin-orbit coupling this invariance is lost and Larmor's theorem is broken: for systems of interacting electrons, this gives rise to a subtle interplay between the spin-orbit coupling acting on individual single-particle states and Coulomb many-body effects. We consider a quasi-two-dimensional, partially spin-polarized electron gas in a semiconductor quantum well in the presence of Rashba and Dresselhaus spin-orbit coupling. Using a linear-response approach based on time-dependent density-functional theory, we calculate the dispersions of spin-flip waves. We obtain analytic results for small wave vectors and up to second order in the Rashba and Dresselhaus coupling strengths α and β . Comparison with experimental data from inelastic light scattering allows us to extract α and β as well as the spin-wave stiffness very accurately. We find significant deviations from the local density approximation for spin-dependent electron systems.

  8. Asteroid spin-rate studies using large sky-field surveys

    Science.gov (United States)

    Chang, Chan-Kao; Lin, Hsing-Wen; Ip, Wing-Huen; Prince, Thomas A.; Kulkarni, Shrinivas R.; Levitan, David; Laher, Russ; Surace, Jason

    2017-12-01

    Eight campaigns to survey asteroid rotation periods have been carried out using the intermediate Palomar Transient Factory in the past 3 years. 2780 reliable rotation periods were obtained, from which we identified two new super-fast rotators (SFRs), (335433) 2005 UW163 and (40511) 1999 RE88, and 23 candidate SFRs. Along with other three known super-fast rotators, there are five known SFRs so far. Contrary to the case of rubble-pile asteroids (i.e., bounded aggregations by gravity only), an internal cohesion, ranging from 100 to 1000 Pa, is required to prevent these five SFRs from flying apart because of their super-fast rotations. This cohesion range is comparable with that of lunar regolith. However, some candidates of several kilometers in size require unusually high cohesion (i.e., a few thousands of Pa). Therefore, the confirmation of these kilometer-sized candidates can provide important information about asteroid interior structure. From the rotation periods we collected, we also found that the spin-rate limit of C-type asteroids, which has a lower bulk density, is lower than for S-type asteroids. This result is in agreement with the general picture of rubble-pile asteroids (i.e., lower bulk density, lower spin-rate limit). Moreover, the spin-rate distributions of asteroids of 3 5 rev/day, regardless of the location in the main belt. The YORP effect is indicated to be less efficient in altering asteroid spin rates from our results when compared with the flat distribution found by Pravec et al. (Icarus 197:497-504, 2008. doi: 10.1016/j.icarus.2008.05.012). We also found a significant number drop at f = 5 rev/day in the spin-rate distributions of asteroids of D < 3 km.

  9. Molecular spinning by a chiral train of short laser pulses

    Science.gov (United States)

    Floß, Johannes; Averbukh, Ilya Sh.

    2012-12-01

    We provide a detailed theoretical analysis of molecular rotational excitation by a chiral pulse train, a sequence of linearly polarized pulses with the polarization direction rotating from pulse to pulse by a controllable angle. Molecular rotation with a preferential rotational sense (clockwise or counterclockwise) can be excited by this scheme. We show that the directionality of the rotation is caused by quantum interference of different excitation pathways. The chiral pulse train is capable of selective excitation of molecular isotopologs and nuclear spin isomers in a mixture. We demonstrate this using 14N2 and 15N2 as examples for isotopologs and para- and ortho-nitrogen as examples for nuclear-spin isomers.

  10. Investigation of antimagnetic rotation in 100Pd

    International Nuclear Information System (INIS)

    Zhu, S.; Garg, U.; Afanasjev, A. V.; Frauendorf, S.; Kharraja, B.; Ghugre, S. S.; Chintalapudi, S. N.; Janssens, R. V. F.; Carpenter, M. P.; Kondev, F. G.

    2001-01-01

    High spin states have been studied in the nucleus 100 Pd with the aim of investigating the novel phenomenon of ''antimagnetic rotation.'' A cascade of four ''rotational-band-like'' transitions is proposed as corresponding to antimagnetic rotation, based on the observed spectroscopic properties and a comparison with calculations in the configuration-dependent cranked Nilsson-Strutinsky formalism

  11. Electropumping of water with rotating electric fields

    DEFF Research Database (Denmark)

    Hansen, Jesper Schmidt; De Luca, Sergio; Todd, Billy

    2013-01-01

    exploiting the coupling of spin angular momentum to linear streaming momentum. A spatially uniform rotating electric field is applied to water molecules, which couples to their permanent electric dipole moments. The resulting molecular rotational momentum is converted into linear streaming momentum...

  12. Spinning gravitating objects in the effective field theory in the post-Newtonian scheme

    Energy Technology Data Exchange (ETDEWEB)

    Levi, Michele [Université Pierre et Marie Curie-Paris VI, CNRS-UMR 7095,Institut d’Astrophysique de Paris, 98 bis Boulevard Arago, 75014 Paris (France); Sorbonne Universités, Institut Lagrange de Paris,98 bis Boulevard Arago, 75014 Paris (France); Steinhoff, Jan [Max-Planck-Institute for Gravitational Physics (Albert-Einstein-Institute),Am Mühlenberg 1, 14476 Potsdam-Golm (Germany); Centro Multidisciplinar de Astrofisica, Instituto Superior Tecnico, Universidade de Lisboa,Avenida Rovisco Pais 1, 1049-001 Lisboa (Portugal)

    2015-09-30

    We introduce a formulation for spinning gravitating objects in the effective field theory in the post-Newtonian scheme in the context of the binary inspiral problem. We aim at an effective action, where all field modes below the orbital scale are integrated out. We spell out the relevant degrees of freedom, in particular the rotational ones, and the associated symmetries. Building on these symmetries, we introduce the minimal coupling part of the point particle action in terms of gauge rotational variables, and construct the spin-induced nonminimal couplings, where we obtain the leading order couplings to all orders in spin. We specify the gauge for the rotational variables, where the unphysical degrees of freedom are eliminated already from the Feynman rules, and all the orbital field modes are integrated out. The equations of motion of the spin can be directly obtained via a proper variation of the action, and Hamiltonians may be straightforwardly derived. We implement this effective field theory for spin to derive all spin dependent potentials up to next-to-leading order to quadratic level in spin, namely up to the third post-Newtonian order for rapidly rotating compact objects. In particular, the proper next-to-leading order spin-squared potential and Hamiltonian for generic compact objects are also derived. For the implementations we use the nonrelativistic gravitational field decomposition, which is found here to eliminate higher-loop Feynman diagrams also in spin dependent sectors, and facilitates derivations. This formulation for spin is thus ideal for treatment of higher order spin dependent sectors.

  13. A review on prognostic techniques for non-stationary and non-linear rotating systems

    Science.gov (United States)

    Kan, Man Shan; Tan, Andy C. C.; Mathew, Joseph

    2015-10-01

    The field of prognostics has attracted significant interest from the research community in recent times. Prognostics enables the prediction of failures in machines resulting in benefits to plant operators such as shorter downtimes, higher operation reliability, reduced operations and maintenance cost, and more effective maintenance and logistics planning. Prognostic systems have been successfully deployed for the monitoring of relatively simple rotating machines. However, machines and associated systems today are increasingly complex. As such, there is an urgent need to develop prognostic techniques for such complex systems operating in the real world. This review paper focuses on prognostic techniques that can be applied to rotating machinery operating under non-linear and non-stationary conditions. The general concept of these techniques, the pros and cons of applying these methods, as well as their applications in the research field are discussed. Finally, the opportunities and challenges in implementing prognostic systems and developing effective techniques for monitoring machines operating under non-stationary and non-linear conditions are also discussed.

  14. Habitability of extrasolar planets and tidal spin evolution.

    Science.gov (United States)

    Heller, René; Barnes, Rory; Leconte, Jérémy

    2011-12-01

    Stellar radiation has conservatively been used as the key constraint to planetary habitability. We review here the effects of tides, exerted by the host star on the planet, on the evolution of the planetary spin. Tides initially drive the rotation period and the orientation of the rotation axis into an equilibrium state but do not necessarily lead to synchronous rotation. As tides also circularize the orbit, eventually the rotation period does equal the orbital period and one hemisphere will be permanently irradiated by the star. Furthermore, the rotational axis will become perpendicular to the orbit, i.e. the planetary surface will not experience seasonal variations of the insolation. We illustrate here how tides alter the spins of planets in the traditional habitable zone. As an example, we show that, neglecting perturbations due to other companions, the Super-Earth Gl581d performs two rotations per orbit and that any primordial obliquity has been eroded.

  15. Comparison of dynamic dual spin-echo and fast-gradient-echo techniques in the evaluation of cardiac diseases

    International Nuclear Information System (INIS)

    Pettigrew, R.I.; Eisner, R.L.; Groen, J.P.; Baron, M.G.

    1987-01-01

    To determine the relative roles of a dynamic spin-echo method and a fast acquisition with multiphase excitations (FAME) technique, ten patients with myocardial infarction (MI), five with myocardial masses, and five healthy patients were studied with both methods. The dynamic dual-spin-echo (DSE) technique allows acquisition of each of seven sections at 14 cardiac phases in 20 minutes. Wall motion abnormalities were seen equally well with both techniques, but FAME usually required a shorter study time (10 minutes). DSE, however, was superior for evaluating cardiac masses and provided superior wall blood contrast. Thus, these techniques are complementary, and both are now a routine part of the authors' study of cardiac patients

  16. Muon spin relaxation and rotation studies of the filled skutterudite alloys praseodymium osmium ruthenium antimonide and praseodymium lanthanum osmium antimonide

    Science.gov (United States)

    Shu, Lei

    Some filled skutterudite compounds have recently been found to exhibit very interesting properties. The first Pr-based heavy-fermion superconductor, PrOs4Sb12, is an intriguing material due to the unusual properties of both its normal and superconducting states. Comprehensive muon spin rotation and relaxation studies and magnetic susceptibility measurements, described in this dissertation, have been performed to investigate the microscopic properties of PrOs4Sb12 and its Ru and La doped alloys. The temperature dependence of penetration depth measured in the vortex state of PrOs4Sb12 using transverse-field muon spin rotation (TF-muSR) is weaker than those measured by radiofrequency measurements. A scenario based on two-band superconductivity in PrOs4Sb 12, is proposed to resolve this difference. TF-muSR experiments also suggest the suppression of superfluid density with Ru doping, probably due to impurity scattering. In addition, magnetic susceptibility data as well as analysis of the muSR data in PrOs4Sb12 reveal a nearly linear relation of mu+ Knight shift vs. magnetic susceptibility. This suggests that the muon charge does not affect the crystalline electric field splitting of Pr3+ near neighbors. Additional evidence comes from the fact that the superconducting transition temperature Tc measured from muSR is consistent with the bulk superconducting values. Zero-field muon spin relaxation (ZF-muSR) experiments have been carried out in the Pr(Os1-xRux) 4Sb12 and Pr1-yLayOs 4Sb12 alloy systems to investigate the time-reversal symmetry (TRS) breaking found in an earlier ZF-muSR study of the end compound PrOs 4Sb12. The results from measurements at KEK, Japan, suggest that Ru doping is considerably more efficient than La doping in suppressing TRS breaking superconducting in PrOs4Sb12. However, we think that the spontaneous local field that indicates TRS breaking detected by ZF-muSR may depend on sample quality if those fields are from inhomogeneity in the

  17. Evaluation of footprint contact area and pressure using a triple-row modification of the suture-bridge technique for rotator cuff repair.

    Science.gov (United States)

    Ostrander, Roger V; McKinney, Bart I

    2012-10-01

    Studies suggest that arthroscopic repair techniques may have high recurrence rates for larger rotator cuff tears. A more anatomic repair may improve the success rate when performing arthroscopic rotator cuff repair. We hypothesized that a triple-row modification of the suture-bridge technique for rotator cuff repair would result in significantly more footprint contact area and pressure between the rotator cuff and the humeral tuberosity. Eighteen ovine infraspinatus tendons were repaired using 1 of 3 simulated arthroscopic techniques: a double-row repair, the suture-bridge technique, and a triple-row repair. The triple-row repair technique is a modification of the suture-bridge technique that uses an additional reducing anchor between the medial and lateral rows. Six samples were tested per group. Pressure-indicating film was used to measure the footprint contact area and pressure after each repair. The triple-row repair resulted in significantly more rotator cuff footprint contact area and contact pressure compared with the double-row technique and the standard suture-bridge technique. No statistical difference in contact area or contact pressure was found between the double-row technique and the suture-bridge technique. The triple-row technique for rotator cuff repair results in significantly more footprint contact area and contact pressure compared with the double-row and standard suture-bridge techniques. This more anatomic repair may improve the healing rate when performing arthroscopic rotator cuff repair. Copyright © 2012 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

  18. Simultaneous double-rod rotation technique in posterior instrumentation surgery for correction of adolescent idiopathic scoliosis.

    Science.gov (United States)

    Ito, Manabu; Abumi, Kuniyoshi; Kotani, Yoshihisa; Takahata, Masahiko; Sudo, Hideki; Hojo, Yoshihiro; Minami, Akio

    2010-03-01

    The authors present a new posterior correction technique consisting of simultaneous double-rod rotation using 2 contoured rods and polyaxial pedicle screws with or without Nesplon tapes. The purpose of this study is to introduce the basic principles and surgical procedures of this new posterior surgery for correction of adolescent idiopathic scoliosis. Through gradual rotation of the concave-side rod by 2 rod holders, the convex-side rod simultaneously rotates with the the concave-side rod. This procedure does not involve any force pushing down the spinal column around the apex. Since this procedure consists of upward pushing and lateral translation of the spinal column with simultaneous double-rod rotation maneuvers, it is simple and can obtain thoracic kyphosis as well as favorable scoliosis correction. This technique is applicable not only to a thoracic single curve but also to double major curves in cases of adolescent idiopathic scoliosis.

  19. Time-resolved lateral spin-caloric transport of optically generated spin packets in n-GaAs

    Science.gov (United States)

    Göbbels, Stefan; Güntherodt, Gernot; Beschoten, Bernd

    2018-05-01

    We report on lateral spin-caloric transport (LSCT) of electron spin packets which are optically generated by ps laser pulses in the non-magnetic semiconductor n-GaAs at K. LSCT is driven by a local temperature gradient induced by an additional cw heating laser. The spatio-temporal evolution of the spin packets is probed using time-resolved Faraday rotation. We demonstrate that the local temperature-gradient induced spin diffusion is solely driven by a non-equilibrium hot spin distribution, i.e. without involvement of phonon drag effects. Additional electric field-driven spin drift experiments are used to verify directly the validity of the non-classical Einstein relation for moderately doped semiconductors at low temperatures for near band-gap excitation.

  20. Orbital rotation without orbital angular momentum: mechanical action of the spin part of the internal energy flow in light beams

    DEFF Research Database (Denmark)

    Angelsky, O. V.; Bekshaev, A. Ya; Maksimyak, P. P.

    2012-01-01

    flow upon tight focusing of the beam, usually applied for energy flow detection by means of the mechanical action upon probe particles. We propose a two-beam interference technique that results in an appreciable level of spin flow in moderately focused beams and detection of the orbital motion of probe...... particles within a field where the transverse energy circulation is associated exclusively with the spin flow. This result can be treated as the first demonstration of mechanical action of the spin flow of a light field....

  1. THE SHORT ROTATION PERIOD OF HI’IAKA, HAUMEA’S LARGEST SATELLITE

    Energy Technology Data Exchange (ETDEWEB)

    Hastings, Danielle M.; Margot, Jean-Luc [University of California, Los Angeles, Department of Earth, Planetary, and Space Sciences, 595 Charles Young Drive East, Los Angeles, CA 90095 (United States); Ragozzine, Darin [Florida Institute of Technology, Department of Physics and Space Sciences, 150 West University Boulevard, Melbourne, FL 32901 (United States); Fabrycky, Daniel C. [Department of Astronomy and Astrophysics, University of Chicago, 5640 South Ellis Avenue, Chicago, IL 60637 (United States); Burkhart, Luke D.; Holman, Matthew [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Fuentes, Cesar [Departamento de Astronomía, Universidad de Chile, Camino El Observatorio 1515, Santiago (Chile); Brown, Michael E., E-mail: dhastings@g.ucla.edu [California Institute of Technology, Division of Geological and Planetary Sciences, MC 150-21, Pasadena, CA 91125 (United States)

    2016-12-01

    Hi’iaka is the larger outer satellite of the dwarf planet Haumea. Using relative photometry from the Hubble Space Telescope and Magellan and a phase dispersion minimization analysis, we have identified the rotation period of Hi’iaka to be ∼9.8 hr (double peaked). This is ∼120 times faster than its orbital period, creating new questions about the formation of this system and possible tidal evolution. The rapid rotation suggests that Hi’iaka could have a significant obliquity and spin precession that could be visible in light curves within a few years. We then turn to an investigation of what we learn about the (currently unclear) formation of the Haumea system and family based on this unexpectedly rapid rotation rate. We explore the importance of the initial semimajor axis and rotation period in tidal evolution theory and find that they strongly influence the time required to despin to synchronous rotation, relevant to understanding a wide variety of satellite and binary systems. We find that despinning tides do not necessarily lead to synchronous spin periods for Hi’iaka, even if it formed near the Roche limit. Therefore, the short rotation period of Hi’iaka does not rule out significant tidal evolution. Hi’iaka’s spin period is also consistent with formation near its current location and spin-up due to Haumea-centric impactors.

  2. Rotary spin echoes

    Energy Technology Data Exchange (ETDEWEB)

    Solomon, I. [Commissariat a l' energie atomique et aux energies alternatives - CEA, Centre d' Etudes Nucleaires de Saclay, BP2, Gif-sur-Yvette (France)

    1959-07-01

    Torrey has observed the free precession of nuclear spins around an r-f field H{sub 1}, fixed in a frame rotating at the Larmor frequency ω{sub 0} = γH{sub 0} around a large d-c magnetic field H{sub 0}. He showed that for an H{sub 1}, much larger than inhomogeneity of H{sub 0}, the latter has a negligible effect on the decay of the spin magnetization which is mainly due to the inhomogeneity of H{sub 1}. We report here on a method of overcoming the inhomogeneity of H{sub 1}, by production of echoes in the rotating frame ('rotary echoes'). These echoes are obtained by a 180 deg. phase shift at t = τ on the r-f field so that H{sub 1}, is suddenly reversed, producing a re-focussing of the magnetization vectors at the time t = 2 τ. The rotary echoes so obtained are very similar to the usual spin-echoes with, however some specific features that make them particularly suitable for the measurement of long relaxation times. Reprint of a paper published in Physical Review Letters, vol. 2, no. 7, Apr 1959, p. 301-302.

  3. Rotary spin echoes

    International Nuclear Information System (INIS)

    Solomon, I.

    1959-01-01

    Torrey has observed the free precession of nuclear spins around an r-f field H 1 , fixed in a frame rotating at the Larmor frequency ω 0 = γH 0 around a large d-c magnetic field H 0 . He showed that for an H 1 , much larger than inhomogeneity of H 0 , the latter has a negligible effect on the decay of the spin magnetization which is mainly due to the inhomogeneity of H 1 . We report here on a method of overcoming the inhomogeneity of H 1 , by production of echoes in the rotating frame ('rotary echoes'). These echoes are obtained by a 180 deg. phase shift at t = τ on the r-f field so that H 1 , is suddenly reversed, producing a re-focussing of the magnetization vectors at the time t = 2 τ. The rotary echoes so obtained are very similar to the usual spin-echoes with, however some specific features that make them particularly suitable for the measurement of long relaxation times. Reprint of a paper published in Physical Review Letters, vol. 2, no. 7, Apr 1959, p. 301-302

  4. Electron spin control and spin-libration coupling of a levitated nanodiamond

    Science.gov (United States)

    Hoang, Thai; Ma, Yue; Ahn, Jonghoon; Bang, Jaehoon; Robicheaux, Francis; Gong, Ming; Yin, Zhang-Qi; Li, Tongcang

    2017-04-01

    Hybrid spin-mechanical systems have great potentials in sensing, macroscopic quantum mechanics, and quantum information science. Recently, we optically levitated a nanodiamond and demonstrated electron spin control of its built-in nitrogen-vacancy (NV) centers in vacuum. We also observed the libration (torsional vibration) of a nanodiamond trapped by a linearly polarized laser beam in vacuum. We propose to achieve strong coupling between the electron spin of a NV center and the libration of a levitated nanodiamond with a uniform magnetic field. With a uniform magnetic field, multiple spins can couple to the torsional vibration at the same time. We propose to use this strong coupling to realize the Lipkin-Meshkov-Glick (LMG) model and generate rotational superposition states. This work is supported by the National Science Foundation under Grant No. 1555035-PHY.

  5. Theory of generation of angular momentum of phonons by heat current and its conversion to spins

    Science.gov (United States)

    Hamada, Masato; Murakami, Shuichi

    Spin-rotation coupling in crystals will enable us to convert between spin current and mechanical rotations, as has been studied in surface acoustic waves, in liquid metals, and in carbon nanotubes. In this presentation we focus on angular momentum of phonons. In nonmagnetic crystals without inversion symmetry, we theoretically demonstrate that phonon modes generally have angular momenta depending on their wave vectors. In equilibrium the sum of the angular momenta is zero. On the other hand, if a heat current flows in the crystal, nonequilibrium phonon distribution leads to nonzero total angular momentum of phonons. It can be observed as a rotation of crystal itself, and as a spin current induced by these phonons via the spin-rotation coupling.

  6. Single-row versus double-row rotator cuff repair: techniques and outcomes.

    Science.gov (United States)

    Dines, Joshua S; Bedi, Asheesh; ElAttrache, Neal S; Dines, David M

    2010-02-01

    Double-row rotator cuff repair techniques incorporate a medial and lateral row of suture anchors in the repair configuration. Biomechanical studies of double-row repair have shown increased load to failure, improved contact areas and pressures, and decreased gap formation at the healing enthesis, findings that have provided impetus for clinical studies comparing single-row with double-row repair. Clinical studies, however, have not yet demonstrated a substantial improvement over single-row repair with regard to either the degree of structural healing or functional outcomes. Although double-row repair may provide an improved mechanical environment for the healing enthesis, several confounding variables have complicated attempts to establish a definitive relationship with improved rates of healing. Appropriately powered rigorous level I studies that directly compare single-row with double-row techniques in matched tear patterns are necessary to further address these questions. These studies are needed to justify the potentially increased implant costs and surgical times associated with double-row rotator cuff repair.

  7. Nuclear spin-lattice relaxation in nitroxide spin-label EPR.

    Science.gov (United States)

    Marsh, Derek

    2016-11-01

    Nuclear relaxation is a sensitive monitor of rotational dynamics in spin-label EPR. It also contributes competing saturation transfer pathways in T 1 -exchange spectroscopy, and the determination of paramagnetic relaxation enhancement in site-directed spin labelling. A survey shows that the definition of nitrogen nuclear relaxation rate W n commonly used in the CW-EPR literature for 14 N-nitroxyl spin labels is inconsistent with that currently adopted in time-resolved EPR measurements of saturation recovery. Redefinition of the normalised 14 N spin-lattice relaxation rate, b=W n /(2W e ), preserves the expressions used for CW-EPR, whilst rendering them consistent with expressions for saturation recovery rates in pulsed EPR. Furthermore, values routinely quoted for nuclear relaxation times that are deduced from EPR spectral diffusion rates in 14 N-nitroxyl spin labels do not accord with conventional analysis of spin-lattice relaxation in this three-level system. Expressions for CW-saturation EPR with the revised definitions are summarised. Data on nitrogen nuclear spin-lattice relaxation times are compiled according to the three-level scheme for 14 N-relaxation: T 1 n =1/W n . Results are compared and contrasted with those for the two-level 15 N-nitroxide system. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Rotational partition functions for linear molecules

    International Nuclear Information System (INIS)

    McDowell, R.S.

    1988-01-01

    An accurate closed-form expression for the rotational partition function of linear polyatomic molecules in 1 summation electronic states is derived, including the effect of nuclear spin (significant at very low temperatures) and of quartic and sextic centrifugal distortion terms (significant at moderate and high temperatures). The proper first-order quantum correction to the classical rigid-rotator partition function is shown to yield Q/sub r/ ≅β -1 exp(β/3), where βequivalenthcB/kT and B is the rotational constant in cm -1 ; for β≥0.2 additional power-series terms in β are necessary. Comparison between the results of this treatment and exact summations are made for HCN and C 2 H 2 at temperatures from 2 to 5000 K, including separate evaluation of the contributions of nuclear spin and centrifugal distortion

  9. Spinning superfluid 4He nanodroplets

    Science.gov (United States)

    Ancilotto, Francesco; Barranco, Manuel; Pi, Martí

    2018-05-01

    We have studied spinning superfluid 4He nanodroplets at zero temperature using density functional theory. Due to the irrotational character of the superfluid flow, the shapes of the spinning nanodroplets are very different from those of a viscous normal fluid drop in steady rotation. We show that when vortices are nucleated inside the superfluid droplets, their morphology, which evolves from axisymmetric oblate to triaxial prolate to two-lobed shapes, is in good agreement with experiments. The presence of vortex arrays confers to the superfluid droplets the rigid-body behavior of a normal fluid in steady rotation, and this is the ultimate reason for the surprising good agreement between recent experiments and the classical models used for their description.

  10. Electron spin dynamics of Ce.sup.3+./sup. ions in YAG crystals studied by pulse-EPR and pump-probe Faraday rotation

    Czech Academy of Sciences Publication Activity Database

    Azamat, Dmitry; Belykh, V.V.; Yakovlev, D.R.; Fobbe, F.; Feng, D.H.; Evers, E.; Jastrabík, Lubomír; Dejneka, Alexandr; Bayer, M.

    2017-01-01

    Roč. 96, č. 7 (2017), s. 1-10, č. článku 075160. ISSN 2469-9950 R&D Projects: GA MŠk LO1409; GA ČR GA16-22092S Institutional support: RVO:68378271 Keywords : electron spin dynamics * Ce 3+ ions * YAG crystals * pulse-EPR * Faraday rotation Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 3.836, year: 2016

  11. Spin transfer torque in antiferromagnetic spin valves: From clean to disordered regimes

    KAUST Repository

    Saidaoui, Hamed Ben Mohamed; Manchon, Aurelien; Waintal, Xavier

    2014-01-01

    Current-driven spin torques in metallic spin valves composed of antiferromagnets are theoretically studied using the nonequilibrium Green's function method implemented on a tight-binding model. We focus our attention on G-type and L-type antiferromagnets in both clean and disordered regimes. In such structures, spin torques can either rotate the magnetic order parameter coherently (coherent torque) or compete with the internal antiferromagnetic exchange (exchange torque). We show that, depending on the symmetry of the spin valve, the coherent and exchange torques can either be in the plane, ∝n×(q×n) or out of the plane ∝n×q, where q and n are the directions of the order parameter of the polarizer and the free antiferromagnetic layers, respectively. Although disorder conserves the symmetry of the torques, it strongly reduces the torque magnitude, pointing out the need for momentum conservation to ensure strong spin torque in antiferromagnetic spin valves.

  12. Spin transfer torque in antiferromagnetic spin valves: From clean to disordered regimes

    KAUST Repository

    Saidaoui, Hamed Ben Mohamed

    2014-05-28

    Current-driven spin torques in metallic spin valves composed of antiferromagnets are theoretically studied using the nonequilibrium Green\\'s function method implemented on a tight-binding model. We focus our attention on G-type and L-type antiferromagnets in both clean and disordered regimes. In such structures, spin torques can either rotate the magnetic order parameter coherently (coherent torque) or compete with the internal antiferromagnetic exchange (exchange torque). We show that, depending on the symmetry of the spin valve, the coherent and exchange torques can either be in the plane, ∝n×(q×n) or out of the plane ∝n×q, where q and n are the directions of the order parameter of the polarizer and the free antiferromagnetic layers, respectively. Although disorder conserves the symmetry of the torques, it strongly reduces the torque magnitude, pointing out the need for momentum conservation to ensure strong spin torque in antiferromagnetic spin valves.

  13. Spin-orbit qubit in a semiconductor nanowire.

    Science.gov (United States)

    Nadj-Perge, S; Frolov, S M; Bakkers, E P A M; Kouwenhoven, L P

    2010-12-23

    Motion of electrons can influence their spins through a fundamental effect called spin-orbit interaction. This interaction provides a way to control spins electrically and thus lies at the foundation of spintronics. Even at the level of single electrons, the spin-orbit interaction has proven promising for coherent spin rotations. Here we implement a spin-orbit quantum bit (qubit) in an indium arsenide nanowire, where the spin-orbit interaction is so strong that spin and motion can no longer be separated. In this regime, we realize fast qubit rotations and universal single-qubit control using only electric fields; the qubits are hosted in single-electron quantum dots that are individually addressable. We enhance coherence by dynamically decoupling the qubits from the environment. Nanowires offer various advantages for quantum computing: they can serve as one-dimensional templates for scalable qubit registers, and it is possible to vary the material even during wire growth. Such flexibility can be used to design wires with suppressed decoherence and to push semiconductor qubit fidelities towards error correction levels. Furthermore, electrical dots can be integrated with optical dots in p-n junction nanowires. The coherence times achieved here are sufficient for the conversion of an electronic qubit into a photon, which can serve as a flying qubit for long-distance quantum communication.

  14. Quark Deconfinement in Rotating Neutron Stars

    Directory of Open Access Journals (Sweden)

    Richard D. Mellinger

    2017-01-01

    Full Text Available In this paper, we use a three flavor non-local Nambu–Jona-Lasinio (NJL model, an improved effective model of Quantum Chromodynamics (QCD at low energies, to investigate the existence of deconfined quarks in the cores of neutron stars. Particular emphasis is put on the possible existence of quark matter in the cores of rotating neutron stars (pulsars. In contrast to non-rotating neutron stars, whose particle compositions do not change with time (are frozen in, the type and structure of the matter in the cores of rotating neutron stars depends on the spin frequencies of these stars, which opens up a possible new window on the nature of matter deep in the cores of neutron stars. Our study shows that, depending on mass and rotational frequency, up to around 8% of the mass of a massive neutron star may be in the mixed quark-hadron phase, if the phase transition is treated as a Gibbs transition. We also find that the gravitational mass at which quark deconfinement occurs in rotating neutron stars varies quadratically with spin frequency, which can be fitted by a simple formula.

  15. Time-dependent dynamical behavior of surface tension on rotating fluids under microgravity environment

    Science.gov (United States)

    Hung, R. J.; Tsao, Y. D.; Hong, B. B.; Leslie, F. W.

    1988-01-01

    Time dependent evolutions of the profile of free surface (bubble shapes) for a cylindrical container partially filled with a Newtonian fluid of constant density, rotating about its axis of symmetry, have been studied. Numerical computations of the dynamics of bubble shapes have been carried out with the following situations: (1) linear functions of spin-up and spin-down in low and microgravity environments, (2) step functions of spin-up and spin-down in a low gravity environment, and (3) sinusoidal function oscillation of gravity environment in high and low rotating cylinder speeds.

  16. Quantum computing with acceptor spins in silicon.

    Science.gov (United States)

    Salfi, Joe; Tong, Mengyang; Rogge, Sven; Culcer, Dimitrie

    2016-06-17

    The states of a boron acceptor near a Si/SiO2 interface, which bind two low-energy Kramers pairs, have exceptional properties for encoding quantum information and, with the aid of strain, both heavy hole and light hole-based spin qubits can be designed. Whereas a light-hole spin qubit was introduced recently (arXiv:1508.04259), here we present analytical and numerical results proving that a heavy-hole spin qubit can be reliably initialised, rotated and entangled by electrical means alone. This is due to strong Rashba-like spin-orbit interaction terms enabled by the interface inversion asymmetry. Single qubit rotations rely on electric-dipole spin resonance (EDSR), which is strongly enhanced by interface-induced spin-orbit terms. Entanglement can be accomplished by Coulomb exchange, coupling to a resonator, or spin-orbit induced dipole-dipole interactions. By analysing the qubit sensitivity to charge noise, we demonstrate that interface-induced spin-orbit terms are responsible for sweet spots in the dephasing time [Formula: see text] as a function of the top gate electric field, which are close to maxima in the EDSR strength, where the EDSR gate has high fidelity. We show that both qubits can be described using the same starting Hamiltonian, and by comparing their properties we show that the complex interplay of bulk and interface-induced spin-orbit terms allows a high degree of electrical control and makes acceptors potential candidates for scalable quantum computation in Si.

  17. Spin-polarized spin excitation spectroscopy

    International Nuclear Information System (INIS)

    Loth, Sebastian; Lutz, Christopher P; Heinrich, Andreas J

    2010-01-01

    We report on the spin dependence of elastic and inelastic electron tunneling through transition metal atoms. Mn, Fe and Cu atoms were deposited onto a monolayer of Cu 2 N on Cu(100) and individually addressed with the probe tip of a scanning tunneling microscope. Electrons tunneling between the tip and the substrate exchange energy and spin angular momentum with the surface-bound magnetic atoms. The conservation of energy during the tunneling process results in a distinct onset threshold voltage above which the tunneling electrons create spin excitations in the Mn and Fe atoms. Here we show that the additional conservation of spin angular momentum leads to different cross-sections for spin excitations depending on the relative alignment of the surface spin and the spin of the tunneling electron. For this purpose, we developed a technique for measuring the same local spin with a spin-polarized and a non-spin-polarized tip by exchanging the last apex atom of the probe tip between different transition metal atoms. We derive a quantitative model describing the observed excitation cross-sections on the basis of an exchange scattering process.

  18. Examining transition metal hydrosulfides: The pure rotational spectrum of ZnSH (X̃2A').

    Science.gov (United States)

    Bucchino, M P; Adande, G R; Halfen, D T; Ziurys, L M

    2017-10-21

    The pure rotational spectrum of the ZnSH (X̃ 2 A') radical has been measured using millimeter-wave direct absorption and Fourier transform microwave (FTMW) methods across the frequency range 18-468 GHz. This work is the first gas-phase detection of ZnSH by any spectroscopic technique. Spectra of the 66 ZnSH, 68 ZnSH, and 64 ZnSD isotopologues were also recorded. In the mm-wave study, ZnSH was synthesized in a DC discharge by the reaction of zinc vapor, generated by a Broida-type oven, with H 2 S; for FTMW measurements, the radical was made in a supersonic jet expansion by the same reactants but utilizing a discharge-assisted laser ablation source. Between 7 and 9 rotational transitions were recorded for each isotopologue. Asymmetry components with K a = 0 through 6 were typically measured in the mm-wave region, each split into spin-rotation doublets. In the FTMW spectra, hyperfine interactions were also resolved, arising from the hydrogen or deuterium nuclear spins of I = 1/2 or I = 1, respectively. The data were analyzed using an asymmetric top Hamiltonian, and rotational, spin-rotation, and magnetic hyperfine parameters were determined for ZnSH, as well as the quadrupole coupling constant for ZnSD. The observed spectra clearly indicate that ZnSH has a bent geometry. The r m (1) structure was determined to be r Zn-S = 2.213(5) Å, r S-H = 1.351(3) Å, and θ Zn-S-H = 90.6(1)°, suggesting that the bonding occurs primarily through sulfur p orbitals, analogous to H 2 S. The hyperfine constants indicate that the unpaired electron in ZnSH primarily resides on the zinc nucleus.

  19. Observation of the in-plane spin-dephasing anisotropy in [111]-grown GaAs/AlGaAs quantum well

    International Nuclear Information System (INIS)

    Zhao, Chunbo; Li, Junbin; Yu, Ying; Ni, Haiqiao; Niu, Zhichuan; Zhang, Xinhui

    2014-01-01

    The electron density and temperature dependent in-plane spin-dephasing anisotropy in [111]-grown GaAs quantum well (QW) has been investigated by time-resolved magneto-Kerr rotation technique. Due to the specific symmetry of [111]-grown quantum well, the in-plane Rashba and linear Dresselhaus effective spin-orbit magnetic field is parallel to each other for electron wave vectors in all directions. However, an obvious in-plane spin-dephasing anisotropy comparing [2 ¯ 11] with [01 ¯ 1] crystalline orientations has been observed and discussed in this work. Our results demonstrate the innegligible spin dephasing channel through inhomogeneous broadening induced by the out-of-plane non-linear Dresselhaus field, which arises naturally from the C 3 symmetry of [111]-grown GaAs QW

  20. Magnon Spin-Momentum Locking: Various Spin Vortices and Dirac magnons in Noncollinear Antiferromagnets

    Science.gov (United States)

    Okuma, Nobuyuki

    2017-09-01

    We generalize the concept of the spin-momentum locking to magnonic systems and derive the formula to calculate the spin expectation value for one-magnon states of general two-body spin Hamiltonians. We give no-go conditions for magnon spin to be independent of momentum. As examples of the magnon spin-momentum locking, we analyze a one-dimensional antiferromagnet with the Néel order and two-dimensional kagome lattice antiferromagnets with the 120° structure. We find that the magnon spin depends on its momentum even when the Hamiltonian has the z -axis spin rotational symmetry, which can be explained in the context of a singular band point or a U (1 ) symmetry breaking. A spin vortex in momentum space generated in a kagome lattice antiferromagnet has the winding number Q =-2 , while the typical one observed in topological insulator surface states is characterized by Q =+1 . A magnonic analogue of the surface states, the Dirac magnon with Q =+1 , is found in another kagome lattice antiferromagnet. We also derive the sum rule for Q by using the Poincaré-Hopf index theorem.

  1. Magnon Spin-Momentum Locking: Various Spin Vortices and Dirac magnons in Noncollinear Antiferromagnets.

    Science.gov (United States)

    Okuma, Nobuyuki

    2017-09-08

    We generalize the concept of the spin-momentum locking to magnonic systems and derive the formula to calculate the spin expectation value for one-magnon states of general two-body spin Hamiltonians. We give no-go conditions for magnon spin to be independent of momentum. As examples of the magnon spin-momentum locking, we analyze a one-dimensional antiferromagnet with the Néel order and two-dimensional kagome lattice antiferromagnets with the 120° structure. We find that the magnon spin depends on its momentum even when the Hamiltonian has the z-axis spin rotational symmetry, which can be explained in the context of a singular band point or a U(1) symmetry breaking. A spin vortex in momentum space generated in a kagome lattice antiferromagnet has the winding number Q=-2, while the typical one observed in topological insulator surface states is characterized by Q=+1. A magnonic analogue of the surface states, the Dirac magnon with Q=+1, is found in another kagome lattice antiferromagnet. We also derive the sum rule for Q by using the Poincaré-Hopf index theorem.

  2. Spin-flip configuration interaction singles with exact spin-projection: Theory and applications to strongly correlated systems.

    Science.gov (United States)

    Tsuchimochi, Takashi

    2015-10-14

    Spin-flip approaches capture static correlation with the same computational scaling as the ordinary single reference methods. Here, we extend spin-flip configuration interaction singles (SFCIS) by projecting out intrinsic spin-contamination to make it spin-complete, rather than by explicitly complementing it with spin-coupled configurations. We give a general formalism of spin-projection for SFCIS, applicable to any spin states. The proposed method is viewed as a natural unification of SFCIS and spin-projected CIS to achieve a better qualitative accuracy at a low computational cost. While our wave function ansatz is more compact than previously proposed spin-complete SF approaches, it successfully offers more general static correlation beyond biradicals without sacrificing good quantum numbers. It is also shown that our method is invariant with respect to open-shell orbital rotations, due to the uniqueness of spin-projection. We will report benchmark calculations to demonstrate its qualitative performance on strongly correlated systems, including conical intersections that appear both in ground-excited and excited-excited degeneracies.

  3. Controllable Micro-Particle Rotation and Transportation Using Sound Field Synthesis Technique

    Directory of Open Access Journals (Sweden)

    Shuang Deng

    2018-01-01

    Full Text Available Rotation and transportation of micro-particles using ultrasonically-driven devices shows promising applications in the fields of biological engineering, composite material manufacture, and micro-assembly. Current interest in mechanical effects of ultrasonic waves has been stimulated by the achievements in manipulations with phased array. Here, we propose a field synthesizing method using the fewest transducers to control the orientation of a single non-spherical micro-particle as well as its spatial location. A localized acoustic force potential well is established and rotated by using sound field synthesis technique. The resultant acoustic radiation torque on the trapped target determines its equilibrium angular position. A prototype device consisting of nine transducers with 2 MHz center frequency is designed and fabricated. Controllable rotation of a silica rod with 90 μm length and 15 μm diameter is then successfully achieved. There is a good agreement between the measured particle orientation and the theoretical prediction. Within the same device, spatial translation of the silica rod can also be realized conveniently. When compared with the existing acoustic rotation methods, the employed transducers of our method are strongly decreased, meanwhile, device functionality is improved.

  4. Mergers of Black-Hole Binaries with Aligned Spins: Waveform Characteristics

    Science.gov (United States)

    Kelly, Bernard J.; Baker, John G.; vanMeter, James R.; Boggs, William D.; McWilliams, Sean T.; Centrella, Joan

    2011-01-01

    "We apply our gravitational-waveform analysis techniques, first presented in the context of nonspinning black holes of varying mass ratio [1], to the complementary case of equal-mass spinning black-hole binary systems. We find that, as with the nonspinning mergers, the dominant waveform modes phases evolve together in lock-step through inspiral and merger, supporting the previous model of the binary system as an adiabatically rigid rotator driving gravitational-wave emission - an implicit rotating source (IRS). We further apply the late-merger model for the rotational frequency introduced in [1], along with a new mode amplitude model appropriate for the dominant (2, plus or minus 2) modes. We demonstrate that this seven-parameter model performs well in matches with the original numerical waveform for system masses above - 150 solar mass, both when the parameters are freely fit, and when they are almost completely constrained by physical considerations."

  5. Zero-Field Spin Structure and Spin Reorientations in Layered Organic Antiferromagnet, κ-(BEDT-TTF)2Cu[N(CN)2]Cl, with Dzyaloshinskii-Moriya Interaction

    Science.gov (United States)

    Ishikawa, Rui; Tsunakawa, Hitoshi; Oinuma, Kohsuke; Michimura, Shinji; Taniguchi, Hiromi; Satoh, Kazuhiko; Ishii, Yasuyuki; Okamoto, Hiroyuki

    2018-06-01

    Detailed magnetization measurements enabled us to claim that the layered organic insulator κ-(BEDT-TTF)2Cu[N(CN)2]Cl [BEDT-TTF: bis(ethylenedithio)tetrathiafulvalene] with the Dzyaloshinskii-Moriya interaction has an antiferromagnetic spin structure with the easy axis being the crystallographic c-axis and the net canting moment parallel to the a-axis at zero magnetic field. This zero-field spin structure is significantly different from that proposed in the past studies. The assignment was achieved by arguments including a correction of the direction of the weak ferromagnetism, reinterpretations of magnetization behaviors, and reasoning based on known high-field spin structures. We suggest that only the contributions of the strong intralayer antiferromagnetic interaction, the moderately weak Dzyaloshinskii-Moriya interaction, and the very weak interlayer ferromagnetic interaction can realize this spin structure. On the basis of this model, characteristic magnetic-field dependences of the magnetization can be interpreted as consequences of intriguing spin reorientations. The first reorientation is an unusual spin-flop transition under a magnetic field parallel to the b-axis. Although the existence of this transition is already known, the interpretation of what happens at this transition has been significantly revised. We suggest that this transition can be regarded as a spin-flop phenomenon of the local canting moment. We also claim that half of the spins rotate by 180° at this transition, in contrast to the conventional spin flop transition. The second reorientation is the gradual rotation of the spins during the variation of the magnetic field parallel to the c-axis. In this process, all the spins rotate around the Dzyaloshinskii-Moriya vectors by 90°. The results of our simulation based on the classical spin model well reproduce these spin reorientation behaviors, which strongly support our claimed zero-field spin structure. The present study highlights the

  6. Stability of a dual-spin satellite with two dampers

    Science.gov (United States)

    Alfriend, K. T.; Hubert, C. H.

    1974-01-01

    The rotational stability of a dual-spin satellite consisting of a main body and a symmetric rotor, both spinning about a common axis, is investigated. The main body is equipped with a spring-mass damper, while a partially filled viscous ring damper is mounted on the rapidly spinning rotor. The effect of fluid motion on the rotational stability of the satellite is calculated, considering the fluid as a single particle moving in a tube with viscous damping. Time constants are obtained by solving approximate equations of motion for the nutation-synchronous and the spin-synchronous modes, and the results are found to agree well with the numerical integrations of the exact equations. A limit cycle may exist for some configurations; the nutation angle tends to increase in such cases.

  7. Advantages of Arthroscopic Rotator Cuff Repair With a Transosseous Suture Technique: A Prospective Randomized Controlled Trial.

    Science.gov (United States)

    Randelli, Pietro; Stoppani, Carlo Alberto; Zaolino, Carlo; Menon, Alessandra; Randelli, Filippo; Cabitza, Paolo

    2017-07-01

    Rotator cuff tear is a common finding in patients with painful, poorly functioning shoulders. The surgical management of this disorder has improved greatly and can now be fully arthroscopic. To evaluate clinical and radiological results of arthroscopic rotator cuff repair using 2 different techniques: single-row anchor fixation versus transosseous hardware-free suture repair. Randomized controlled trial; Level of evidence, 1. Sixty-nine patients with rotator cuff tears were enrolled: 35 patients were operated with metal anchors and 34 with standardized transosseous repair. The patients were clinically evaluated before surgery, during the 28 days after surgery, and at least 1 year after the operation by the use of validated rating scores (Constant score, QuickDASH, and numerical rating scale [NRS]). Final follow-up was obtained at more than 3 years by a QuickDASH evaluation to detect any difference from the previous follow-up. During the follow-up, rotator cuff integrity was determined through magnetic resonance imaging and was classified according to the 5 Sugaya categories. Patients operated with the transosseous technique had significantly less pain, especially from the 15th postoperative day: In the third week, the mean NRS value for the anchor group was 3.00 while that for transosseous group was 2.46 ( P = .02); in the fourth week, the values were 2.44 and 1.76, respectively ( P rotator cuff repair integrity, based on Sugaya magnetic resonance imaging classification, no significant difference was found between the 2 techniques in terms of retear rate ( P = .81). No significant differences were found between the 2 arthroscopic repair techniques in terms of functional and radiological results. However, postoperative pain decreased more quickly after the transosseous procedure, which therefore emerges as a possible improvement in the surgical repair of the rotator cuff. Registration: NCT01815177 ( ClinicalTrials.gov identifier).

  8. Rotational Failure of Rubble-pile Bodies: Influences of Shear and Cohesive Strengths

    Science.gov (United States)

    Zhang, Yun; Richardson, Derek C.; Barnouin, Olivier S.; Michel, Patrick; Schwartz, Stephen R.; Ballouz, Ronald-Louis

    2018-04-01

    The shear and cohesive strengths of a rubble-pile asteroid could influence the critical spin at which the body fails and its subsequent evolution. We present results using a soft-sphere discrete element method to explore the mechanical properties and dynamical behaviors of self-gravitating rubble piles experiencing increasing rotational centrifugal forces. A comprehensive contact model incorporating translational and rotational friction and van der Waals cohesive interactions is developed to simulate rubble-pile asteroids. It is observed that the critical spin depends strongly on both the frictional and cohesive forces between particles in contact; however, the failure behaviors only show dependence on the cohesive force. As cohesion increases, the deformation of the simulated body prior to disruption is diminished, the disruption process is more abrupt, and the component size of the fissioned material is increased. When the cohesive strength is high enough, the body can disaggregate into similar-size fragments, which could be a plausible mechanism to form asteroid pairs or active asteroids. The size distribution and velocity dispersion of the fragments in high-cohesion simulations show similarities to the disintegrating asteroid P/2013 R3, indicating that this asteroid may possess comparable cohesion in its structure and experience rotational fission in a similar manner. Additionally, we propose a method for estimating a rubble pile’s friction angle and bulk cohesion from spin-up numerical experiments, which provides the opportunity for making quantitative comparisons with continuum theory. The results show that the present technique has great potential for predicting the behaviors and estimating the material strengths of cohesive rubble-pile asteroids.

  9. Optical spin generation/detection and spin transport lifetimes

    International Nuclear Information System (INIS)

    Miah, M. Idrish

    2011-01-01

    We generate electron spins in semiconductors by optical pumping. The detection of them is also performed by optical technique using time-resolved pump-probe photoluminescence polarization measurements in the presence of an external magnetic field perpendicular to the generated spin. The spin polarization in dependences of the pulse length, pump-probe delay and external magnetic field is studied. From the dependence of spin-polarization on the delay of the probe, the electronic spin transport lifetimes and the spin relaxation frequencies as a function of the strength of the magnetic field are estimated. The results are discussed based on hyperfine effects for interacting electrons.

  10. Optical spin generation/detection and spin transport lifetimes

    Energy Technology Data Exchange (ETDEWEB)

    Miah, M. Idrish, E-mail: m.miah@griffith.edu.au [Department of Physics, University of Chittagong, Chittagong 4331 (Bangladesh)

    2011-02-25

    We generate electron spins in semiconductors by optical pumping. The detection of them is also performed by optical technique using time-resolved pump-probe photoluminescence polarization measurements in the presence of an external magnetic field perpendicular to the generated spin. The spin polarization in dependences of the pulse length, pump-probe delay and external magnetic field is studied. From the dependence of spin-polarization on the delay of the probe, the electronic spin transport lifetimes and the spin relaxation frequencies as a function of the strength of the magnetic field are estimated. The results are discussed based on hyperfine effects for interacting electrons.

  11. Topological defect formation in rotating binary dipolar Bose–Einstein condensate

    International Nuclear Information System (INIS)

    Zhang, Xiao-Fei; Han, Wei; Jiang, Hai-Feng; Liu, Wu-Ming; Saito, Hiroki; Zhang, Shou-Gang

    2016-01-01

    We investigate the topological defects and spin structures of a rotating binary Bose–Einstein condensate, which consists of both dipolar and scalar bosonic atoms confined in spin-dependent optical lattices, for an arbitrary orientation of the dipoles with respect to their plane of motion. Our results show that the tunable dipolar interaction, especially the orientation of the dipoles, can be used to control the direction of stripe phase and its related half-vortex sheets. In addition, it can also be used to obtain a regular arrangement of various topological spin textures, such as meron, circular and cross disgyration spin structures. We point out that such topological defects and regular arrangement of spin structures arise primarily from the long-range and anisotropic nature of dipolar interaction and its competition with the spin-dependent optical lattices and rotation. - Highlights: • Effects of both strength and orientation of the dipoles are discussed. • Various topological defects can be formed in different parameter regions. • Present one possible way to obtain regular arrangements of spin textures.

  12. Spin-flip and spin orbit interactions in heavy ion systems

    International Nuclear Information System (INIS)

    Bybell, D.P.

    1983-01-01

    The role of spin orbit forces in heavy ion reactions is not completely understood. Experimental data is scarce for these systems but the data that does exist indicates a stronger spin orbit force than predicted by the folding models. The spin-flip probability of non-spin zero projectiles is one technique used for these measurements and is often taken as a direct indicator of a spin orbit interaction. This work measures the projectile spin-flip probability for three inelastic reactions; 13 C + 24 Mg, E/sub cm/ = 22.7 MeV; 13 C + 12 C, E/sub cm/ = 17.3 MeV; and 6 Li + 12 C, E/sub cm/ = 15.2 MeV, all leading to the first J/sup π/ = 2 + state of the target. The technique of particle-γ angular correlations was used for measuring the final state density matrix elements, of which the absolute value M = 1 magnetic substate population is equivalent to the spin-flip probability. The method was explored in detail and found to be sensitive to spin-flip probabilities smaller than 1%. The technique was also found to be a good indicator of the reaction mechanism involved. Nonzero and occasionally large spin-flip probabilities were observed in all systems, much larger than the folding model predictions. Information was obtained on the non-spin-flip density matrix elements. In the 13 C + 24 Mg reaction, these were found to agree with calculations when the finite size of the particle detector is included

  13. Biomechanical comparison of single-row arthroscopic rotator cuff repair technique versus transosseous repair technique.

    Science.gov (United States)

    Tocci, Stephen L; Tashjian, Robert Z; Leventhal, Evan; Spenciner, David B; Green, Andrew; Fleming, Braden C

    2008-01-01

    This study determined the effect of tear size on gap formation of single-row simple-suture arthroscopic rotator cuff repair (ARCR) vs transosseous Mason-Allen suture open RCR (ORCR) in 13 pairs of human cadaveric shoulders. A massive tear was created in 6 pairs and a large tear in 7. Repairs were cyclically tested in low-load and high-load conditions, with no significant difference in gap formation. Under low-load, gapping was greater in massive tears. Under high-load, there was a trend toward increased gap with ARCR for large tears. All repairs of massive tears failed in high-load. Gapping was greater posteriorly in massive tears for both techniques. Gap formation of a modeled RCR depends upon the tear size. ARCR of larger tears may have higher failure rates than ORCR, and the posterior aspect appears to be the site of maximum gapping. Specific attention should be directed toward maximizing initial fixation of larger rotator cuff tears, especially at the posterior aspect.

  14. Diagnosis of partial and complete rotator cuff tears using combined gradient echo and spin echo imaging

    International Nuclear Information System (INIS)

    Tuite, M.J.; Yandow, D.R.; DeSmet, A.A.; Orwin, J.F.; Quintana, F.A.

    1994-01-01

    Most magnetic resonance (MR) studies evaluating the rotator cuff for tears have used T2-weighted imaging in the coronal oblique and sagittal oblique planes. T2 * -weighted gradient echo imaging, however, has advantages over spin echo imaging, including contiguous slices without cross-talk, high contrast around the cuff, and intrinsically shorter imaging times which can be used to increase the number of signals averaged and thus improve the signal-to-noise ratio. We reviewed the shoulder MR scans of 87 consecutive patients who underwent both a MR scan and a shoulder arthroscopy during which the size of tears, if present, was graded. The reviewers were blinded as to the history and arthroscopic results. The MR scans included oblique coronal T2 * -weighted gradient echo and oblique sagittal T2-weighted spin echo images. MR cuff grades were correlated with arthroscopic findings. For complete tears, the sensitivity of MR was 0.91 and the specificity 0.95. For partial tears, the sensitivity was 0.74 and the specificity 0.87. This accuracy is similar to two-plane T2-weighted imaging as previously reported in the literature. There was a statistically significant correlation (p < 0.0005) between the cuff grade as determined by MR and the arthroscopic findings. (orig.)

  15. Diagnosis of partial and complete rotator cuff tears using combined gradient echo and spin echo imaging

    Energy Technology Data Exchange (ETDEWEB)

    Tuite, M J [Dept. of Radiology, Univ. of Wisconsin, Madison, WI (United States); Yandow, D R [Dept. of Radiology, Univ. of Wisconsin, Madison, WI (United States); DeSmet, A A [Dept. of Radiology, Univ. of Wisconsin, Madison, WI (United States); Orwin, J F [Div. of Orthopedic Surgery, Univ. of Wisconsin, Madison, WI (United States); Quintana, F A [Dept. of Biostatistics, Univ. of Wisconsin, Madison, WI (United States)

    1994-10-01

    Most magnetic resonance (MR) studies evaluating the rotator cuff for tears have used T2-weighted imaging in the coronal oblique and sagittal oblique planes. T2{sup *}-weighted gradient echo imaging, however, has advantages over spin echo imaging, including contiguous slices without cross-talk, high contrast around the cuff, and intrinsically shorter imaging times which can be used to increase the number of signals averaged and thus improve the signal-to-noise ratio. We reviewed the shoulder MR scans of 87 consecutive patients who underwent both a MR scan and a shoulder arthroscopy during which the size of tears, if present, was graded. The reviewers were blinded as to the history and arthroscopic results. The MR scans included oblique coronal T2{sup *}-weighted gradient echo and oblique sagittal T2-weighted spin echo images. MR cuff grades were correlated with arthroscopic findings. For complete tears, the sensitivity of MR was 0.91 and the specificity 0.95. For partial tears, the sensitivity was 0.74 and the specificity 0.87. This accuracy is similar to two-plane T2-weighted imaging as previously reported in the literature. There was a statistically significant correlation (p < 0.0005) between the cuff grade as determined by MR and the arthroscopic findings. (orig.)

  16. Basis for calculating cross sections for nuclear magnetic resonance spin-modulated polarized neutron scattering.

    Science.gov (United States)

    Kotlarchyk, Michael; Thurston, George M

    2016-12-28

    In this work we study the potential for utilizing the scattering of polarized neutrons from nuclei whose spin has been modulated using nuclear magnetic resonance (NMR). From first principles, we present an in-depth development of the differential scattering cross sections that would arise in such measurements from a hypothetical target system containing nuclei with non-zero spins. In particular, we investigate the modulation of the polarized scattering cross sections following the application of radio frequency pulses that impart initial transverse rotations to selected sets of spin-1/2 nuclei. The long-term aim is to provide a foundational treatment of the scattering cross section associated with enhancing scattering signals from selected nuclei using NMR techniques, thus employing minimal chemical or isotopic alterations, so as to advance the knowledge of macromolecular or liquid structure.

  17. Spin Injection in Indium Arsenide

    Directory of Open Access Journals (Sweden)

    Mark eJohnson

    2015-08-01

    Full Text Available In a two dimensional electron system (2DES, coherent spin precession of a ballistic spin polarized current, controlled by the Rashba spin orbit interaction, is a remarkable phenomenon that’s been observed only recently. Datta and Das predicted this precession would manifest as an oscillation in the source-drain conductance of the channel in a spin-injected field effect transistor (Spin FET. The indium arsenide single quantum well materials system has proven to be ideal for experimental confirmation. The 2DES carriers have high mobility, low sheet resistance, and high spin orbit interaction. Techniques for electrical injection and detection of spin polarized carriers were developed over the last two decades. Adapting the proposed Spin FET to the Johnson-Silsbee nonlocal geometry was a key to the first experimental demonstration of gate voltage controlled coherent spin precession. More recently, a new technique measured the oscillation as a function of channel length. This article gives an overview of the experimental phenomenology of the spin injection technique. We then review details of the application of the technique to InAs single quantum well (SQW devices. The effective magnetic field associated with Rashba spin-orbit coupling is described, and a heuristic model of coherent spin precession is presented. The two successful empirical demonstrations of the Datta Das conductance oscillation are then described and discussed.

  18. Nuclear spins in nanostructures

    International Nuclear Information System (INIS)

    Coish, W.A.; Baugh, J.

    2009-01-01

    We review recent theoretical and experimental advances toward understanding the effects of nuclear spins in confined nanostructures. These systems, which include quantum dots, defect centers, and molecular magnets, are particularly interesting for their importance in quantum information processing devices, which aim to coherently manipulate single electron spins with high precision. On one hand, interactions between confined electron spins and a nuclear-spin environment provide a decoherence source for the electron, and on the other, a strong effective magnetic field that can be used to execute local coherent rotations. A great deal of effort has been directed toward understanding the details of the relevant decoherence processes and to find new methods to manipulate the coupled electron-nuclear system. A sequence of spectacular new results have provided understanding of spin-bath decoherence, nuclear spin diffusion, and preparation of the nuclear state through dynamic polarization and more general manipulation of the nuclear-spin density matrix through ''state narrowing.'' These results demonstrate the richness of this physical system and promise many new mysteries for the future. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  19. Vortices in spin-orbit-coupled Bose-Einstein condensates

    International Nuclear Information System (INIS)

    Radic, J.; Sedrakyan, T. A.; Galitski, V.; Spielman, I. B.

    2011-01-01

    Realistic methods to create vortices in spin-orbit-coupled Bose-Einstein condensates are discussed. It is shown that, contrary to common intuition, rotation of the trap containing a spin-orbit condensate does not lead to an equilibrium state with static vortex structures but gives rise instead to nonequilibrium behavior described by an intrinsically time-dependent Hamiltonian. We propose here the following alternative methods to induce thermodynamically stable static vortex configurations: (i) to rotate both the lasers and the anisotropic trap and (ii) to impose a synthetic Abelian field on top of synthetic spin-orbit interactions. Effective Hamiltonians for spin-orbit condensates under such perturbations are derived for most currently known realistic laser schemes that induce synthetic spin-orbit couplings. The Gross-Pitaevskii equation is solved for several experimentally relevant regimes. The new interesting effects include spatial separation of left- and right-moving spin-orbit condensates, the appearance of unusual vortex arrangements, and parity effects in vortex nucleation where the topological excitations are predicted to appear in pairs. All these phenomena are shown to be highly nonuniversal and depend strongly on a specific laser scheme and system parameters.

  20. Spinning phenomena and energetics of spherically pulsating patterns in stratified fluids

    International Nuclear Information System (INIS)

    Ibragimov, Ranis N; Dameron, Michael

    2011-01-01

    The nonlinear solutions of the two-dimensional Boussinesq equations describing internal waves in rotating stratified fluids were obtained as group invariant solutions. The latter nonlinear solutions correspond to the rotation transformation preserving the form of the original nonlinear equations of motion. It is shown that the obtained class of exact solutions can be associated with the spherically pulsating patterns observed in uniformly stratified fluids. It is also shown that the obtained rotationally symmetric solutions are bounded functions that can be visualized as spinning patterns in stratified fluids. It is also shown that the rotational transformation provides the energy conservation law together with other conservation laws for which the spinning phenomena is observed. The effects of nonlinearity and the Earth's rotation on such a phenomenon are also discussed.

  1. High spin rotational bands in 65 Zn

    Indian Academy of Sciences (India)

    The nucleus 30 65 Zn was studied using the 52Cr(16O, 2)65Zn reaction at a beam energy of 65 MeV. The level scheme is extended up to an excitation energy of 10.57 MeV for spin-parity (41/2ħ) with several newly observed transitions placed in it.

  2. Muon spin rotation study of magnetism and superconductivity in Ba(Fe1-xCox)2As2 single crystals

    DEFF Research Database (Denmark)

    Bernhard, C.; Wang, C. N.; Nuccio, L.

    2012-01-01

    Using muon spin rotation (μSR) we investigated the magnetic and superconducting properties of a series of Ba(Fe1−xCox)2As2 single crystals with 0 ≤x ≤0.15. Our study details how the antiferromagnetic order is suppressed upon Co substitution and how it coexists with superconductivity. In the nonsu......Using muon spin rotation (μSR) we investigated the magnetic and superconducting properties of a series of Ba(Fe1−xCox)2As2 single crystals with 0 ≤x ≤0.15. Our study details how the antiferromagnetic order is suppressed upon Co substitution and how it coexists with superconductivity....... In the nonsuperconducting samples at 0 demonstrated by μSR at x = 0.055 [P. Marsik et al., Phys. Rev. Lett. 105...

  3. Dynamical behavior of surface tension on rotating fluids in low and microgravity environments

    Science.gov (United States)

    Hung, R. J.; Tsao, Y. D.; Hong, B. B.; Leslie, F. W.

    1989-01-01

    Consideration is given to the time-dependent evolutions of the free surface profile (bubble shapes) of a cylindrical container, partially filled with a Newtonian fluid of constant density, rotating about its axis of symmetry in low and microgravity environments. The dynamics of the bubble shapes are calculated for four cases: linear time-dependent functions of spin-up and spin-down in low and microgravity, linear time-dependent functions of increasing and decreasing gravity at high and low rotating cylinder speeds, time-dependent step functions of spin-up and spin-down in low gravity, and sinusoidal function oscillation of the gravity environment in high and low rotating cylinder speeds. It is shown that the computer algorithms developed by Hung et al. (1988) may be used to simulate the profile of time-dependent bubble shapes under variations of centrifugal, capillary, and gravity forces.

  4. Copper electrodeposition in a through-silicon via evaluated by rotating disc electrode techniques

    International Nuclear Information System (INIS)

    Tsai, Tzu-Hsuan; Huang, Jui-Hsiung

    2010-01-01

    Via filling is a critical process for metallization of a through-silicon via (TSV) in a 3D MEMS device. This study uses a rotating disc electrode (RDE) at 1000 rpm, 100 rpm and 10 rpm to simulate the mass-transfer environment of metallization on the wafer surface, at the bottom of shallow vias and the deep vias, respectively. RDE techniques display the difference of suppression action among three rotation speeds clearly. The calculated filling power is higher over a wide surface current density using the plating bath of 50 g L −1 Cu 2+ than that of 25 or 75 g L −1 Cu 2+ . TSV filling in a wafer-segment scale, with 15 µm via diameter and 150 µm via depth, verifies the performance predicted by the RDE techniques

  5. Flow past an axially aligned spinning cylinder: Experimental Study

    Science.gov (United States)

    Carlucci, Pasquale; Buckley, Liam; Mehmedagic, Igbal; Carlucci, Donald; Thangam, Siva

    2017-11-01

    Experimental investigation of flow past a spinning cylinder is presented in the context of its application and relevance to flow past projectiles. A subsonic wind tunnel is used to perform experiments on the flow past a spinning cylinder that is mounted on a forward sting and oriented such that its axis of rotation is aligned with the mean flow. The experiments cover a Reynolds number of range of up to 45000 and rotation numbers of up to 2 (based on cylinder diameter). Time-averaged mean flow and turbulence profiles in the wake flow are presented with and without spin along with comparison to published experimental data. Funded in part by the U. S. Army ARDEC, Picatinny Arsenal, NJ.

  6. Interface-induced chiral domain walls, spin spirals and skyrmions revealed by spin-polarized scanning tunneling microscopy.

    Science.gov (United States)

    von Bergmann, Kirsten; Kubetzka, André; Pietzsch, Oswald; Wiesendanger, Roland

    2014-10-01

    The spin textures of ultra-thin magnetic layers exhibit surprising variety. The loss of inversion symmetry at the interface of the magnetic layer and substrate gives rise to the so-called Dzyaloshinskii-Moriya interaction which favors non-collinear spin arrangements with unique rotational sense. Here we review the application of spin-polarized scanning tunneling microscopy to such systems, which has led to the discovery of interface-induced chiral domain walls and spin spirals. Recently, different interface-driven skyrmion lattices have been found, and the writing as well as the deleting of individual skyrmions based on local spin-polarized current injection has been demonstrated. These interface-induced non-collinear magnetic states offer new exciting possibilities to study fundamental magnetic interactions and to tailor material properties for spintronic applications.

  7. Determination of the activation energy of rotational microviscosity in the DPPC multilayer dispersions and the effects of high electrolyte concentration on rotational microviscosity

    Energy Technology Data Exchange (ETDEWEB)

    Aydas, C. [Ankara Nuclear Research and Training Center, Ankara (Turkmenistan); Korkmaz, M. [Hacettepe University, Beytepe, Ankara (Turkmenistan)

    2004-10-15

    In the present work, electron spin resonance (ESR) spectroscopy was used to study, through the rotational microviscosity approach, the effects of high electrolyte concentrations on the phase behaviors of DPPC (dipalmitoylphosphatidylcholine) multilayer aqueous dispersions of lipid concentrations of 25 mg/ml and 50 mg/ml containing a 5-SASL spin label. The correlation time involved in the definition of rotational microviscosity was calculated using two different equations given in the literature. The activation energies of the rotational viscosity in the gel and the liquid crystal phases and the main transition temperatures were calculated from constructed Andrade plots. The results obtained are discussed in light of the literature data, and the validity of the approach was emphasized.

  8. Spin vectors in the Koronis family: III. (832) Karin

    Science.gov (United States)

    Slivan, Stephen M.; Molnar, Lawrence A.

    2012-08-01

    Studies of asteroid families constrain models of asteroid collisions and evolution processes, and the Karin cluster within the Koronis family is among the youngest families known (Nesvorný, D., Bottke, Jr., W.F., Dones, L., Levison, H.F. [2002]. Nature 417, 720-722). (832) Karin itself is by far the largest member of the Karin cluster, thus knowledge of Karin's spin vector is important to constrain family formation and evolution models that include spin, and to test whether its spin properties are consistent with the Karin cluster being a very young family. We observed rotation lightcurves of Karin during its four consecutive apparitions in 2006-2009, and combined the new observations with previously published lightcurves to determine its spin vector orientation and preliminary model shape. Karin is a prograde rotator with a period of (18.352 ± 0.003) h, spin obliquity near (42 ± 5)°, and pole ecliptic longitude near either (52 ± 5)° or (230 ± 5)°. The spin vector and shape results for Karin will constrain models of family formation that include spin properties; in the meantime we briefly discuss Karin's own spin in the context of those of other members of the Karin cluster and the parent body's siblings in the Koronis family.

  9. Application of interferometry and Faraday rotation techniques for density measurements on ITER

    International Nuclear Information System (INIS)

    Snider, R.T.; Carlstrom, T.N.; Ma, C.H.; Peebles, W.A.

    1995-01-01

    There is a need for real time, reliable density measurement for density control, compatible with the restricted access and radiation environment on ITER. Line average density measurements using microwave or laser interferometry techniques have proven to be robust and reliable for density control on contemporary tokamaks. In ITER, the large path length, high density and density gradients, limit the wavelength of a probing beam to shorter then about 50 microm due to refraction effects. In this paper the authors consider the design of short wavelength vibration compensated interferometers and Faraday rotation techniques for density measurements on ITER. These techniques allow operation of the diagnostics without a prohibitively large vibration isolated structure and permits the optics to be mounted directly on the radial port plugs on ITER. A beam path designed for 10.6 microm (CO2 laser) with a tangential path through the plasma allows both an interferometer and a Faraday rotation measurement of the line average density with good density resolution while avoiding refraction problems. Plasma effects on the probing beams and design tradeoffs will be discussed along with radiation and long pulse issues. A proposed layout of the diagnostic for ITER will be present

  10. [Clinical research of arthroscopic separate double-layer suture bridge technique for delaminated rotator cuff tear].

    Science.gov (United States)

    Ren, Jiangtao; Xu, Cong; Liu, Xianglin; Wang, Jiansong; Li, Zhihuai; Lü, Yongming

    2017-10-01

    To explore the effectiveness of the arthroscopic separate double-layer suture bridge technique in treatment of the delaminated rotator cuff tear. Between May 2013 and May 2015, 54 patients with the delaminated rotator cuff tears were recruited in the study. They were randomly allocated into 2 groups to receive repair either using arthroscopic separate double-layer suture bridge technique (trial group, n =28) or using arthroscopic whole-layer suture bridge technique (control group, n =26). There was no significant difference in gender, age, injured side, tear type, and preoperative visual analogue scale (VAS) score, Constants score, American Shoulder and Elbow Surgeons (ASES) score, University of California Los Angeles (UCLA) score, and the range of motion of shoulder joint between 2 groups ( P >0.05). Postoperative functional scores, range of motion, and recurrence rate of tear in 2 groups were observed and compared. The operation time was significant longer in trial group than in control group ( t =8.383, P =0.000). All incisions healed at stage Ⅰ without postoperative complication. All the patients were followed up 12 months. At 12 months postoperatively, the UCLA score, ASES score, VAS score, Constant score, and the range of motion were significantly improved when compared with the preoperative values in 2 groups ( P 0.05). Four cases (14.3%) of rotator cuff tear recurred in trial group while 5 cases (19.2%) in control group, showing no significant difference ( χ 2 =0.237, P =0.626). Compared with the arthroscopic whole-layer suture bridge technique, arthroscopic separate double-layer suture bridge technique presents no significant difference in the shoulder function score, the range of motion, and recurrence of rotator cuff tear, while having a longer operation time.

  11. Generalized Faraday law derived from classical forces in a rotating frame

    OpenAIRE

    Choi, Taeseung

    2009-01-01

    We show the additional spin dependent classical force due to the rotation of an electron spin's rest frame is essential to derive a spin-Faraday law by using an analogy with the usual Faraday law. The contribution of the additional spin dependent force to the spin-Faraday law is the same as that of the spin geometric phase. With this observations, Faraday law is generalized to include both the usual Faraday and the spin-Faraday laws in a unified manner.

  12. Helical modes generate antimagnetic rotational spectra in nuclei

    Science.gov (United States)

    Malik, Sham S.

    2018-03-01

    A systematic analysis of the antimagnetic rotation band using r -helicity formalism is carried out for the first time. The observed octupole correlation in a nucleus is likely to play a role in establishing the antimagnetic spectrum. Such octupole correlations are explained within the helical orbits. In a rotating field, two identical fermions (generally protons) with paired spins generate these helical orbits in such a way that its positive (i.e., up) spin along the axis of quantization refers to one helicity (right-handedness) while negative (down) spin along the same quantization-axis decides another helicity (left-handedness). Since the helicity remains invariant under rotation, therefore, the quantum state of a fermion is represented by definite angular momentum and helicity. These helicity represented states support a pear-shaped structure of a rotating system having z axis as the symmetry axis. A combined operation of parity, time-reversal, and signature symmetries ensures an absence of one of the signature partner band from the observed antimagnetic spectrum. This formalism has also been tested for the recently observed negative parity Δ I =2 antimagnetic spectrum in odd-A 101Pd nucleus and explains nicely its energy spectrum as well as the B (E 2 ) values. Further, this formalism is found to be fully consistent with twin-shears mechanism popularly known for such type of rotational bands. It also provides significant clue for extending these experiments in various mass regions spread over the nuclear chart.

  13. Heisenberg Model in a Rotating Magnetic Field

    Institute of Scientific and Technical Information of China (English)

    LIN Qiong-Gui

    2005-01-01

    We study the Heisenberg model under the influence of a rotating magnetic field. By using a time-dependent unitary transformation, the time evolution operator for the Schrodinger equation is obtained, which involves no chronological product. The spin vectors (mean values of the spin operators) are obtained as explicit functions of time in the most general case. A series of cyclic solutions are presented. The nonadiabatic geometric phases of these cyclic solutions are calculated, and are expressed in terms of the solid angle subtended by the closed trace of the total spin vector, as well as in terms of those of the individual spins.

  14. Symmetries and rotational line intensities in diatomic molecules

    International Nuclear Information System (INIS)

    Veseth, L.

    1986-02-01

    The general theory of angular momenta and the full rotation group is used to reconsider the theory of the intensity factors of rotational lines in the spectra of diatomic molecules (Hoenl-London factors). It is shown that the use of the rotational symmetry (rotation matrices) leads to compact derivations of the symmetry properties of the molecular wave functions, as well as the matrix elements of the transitions operator. The present work is restricted to spin-allowed electric dipole transitions, and the general sum rule characteristic of this type of transitions is rederived by use of the general angular momentum theory. A main purpose of the present work has been to provide a unified theoretical basis for exact numerical computations of Hoenl-London factors for all types of spin-allowed electric dipole transitions in diatomic molecules. The computed Hoenl-London factors are then in the next step intended to be the basis for construction of synthetic molecular band spectra, with particular applications to upper atmosperic emissions (aurora)

  15. Investigation of antimagnetic rotation in {sup 100}Pd

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, S.; Garg, U.; Afanasjev, A. V.; Frauendorf, S.; Kharraja, B.; Ghugre, S. S.; Chintalapudi, S. N.; Janssens, R. V. F.; Carpenter, M. P.; Kondev, F. G. (and others)

    2001-10-01

    High spin states have been studied in the nucleus {sup 100}Pd with the aim of investigating the novel phenomenon of ''antimagnetic rotation.'' A cascade of four ''rotational-band-like'' transitions is proposed as corresponding to antimagnetic rotation, based on the observed spectroscopic properties and a comparison with calculations in the configuration-dependent cranked Nilsson-Strutinsky formalism.

  16. Development of basic theories and techniques for determining stresses in rotating turbine or compressor blades

    Science.gov (United States)

    Chien, C. H.; Swinson, W. F.; Turner, J. L.; Moslehy, F. A.; Ranson, W. F.

    1980-01-01

    A method for measuring in-plane displacement of a rotating structure by using two laser speckle photographs is described. From the displacement measurements one can calculate strains and stresses due to a centrifugal load. This technique involves making separate speckle photographs of a test model. One photograph is made with the model loaded (model is rotating); the second photograph is made with no load on the model (model is stationary). A sandwich is constructed from the two speckle photographs and data are recovered in a manner similar to that used with conventional speckle photography. The basic theory, experimental procedures of this method, and data analysis of a simple rotating specimen are described. In addition the measurement of in-plane surface displacement components of a deformed solid, and the application of the coupled laser speckle interferometry and boundary-integral solution technique to two dimensional elasticity problems are addressed.

  17. Rotation technique for irradiation of the bladder and the results obtained

    Energy Technology Data Exchange (ETDEWEB)

    Backhouse, T W [Coventry and Warwickshire Hospital (UK). Dept. of Radiotherapy and Oncology

    1979-05-01

    An argument is advanced for the use of partial rotational techniques for the treatment of carcinoma of the bladder. One hundred and seventy cases are analysed; the majority were T3 solid transitional cell lesions with an overall (corrected) survival rate of 24.7%. Salvage cystectomy produced a four-year survival rate of 40% when performed within six months of the radiotherapy.

  18. Anomalous magnetic structure and spin dynamics in magnetoelectric LiFePO4

    DEFF Research Database (Denmark)

    Toft-Petersen, Rasmus; Reehuis, Manfred; Jensen, Thomas Bagger Stibius

    2015-01-01

    We report significant details of the magnetic structure and spin dynamics of LiFePO4 obtained by single-crystal neutron scattering. Our results confirm a previously reported collinear rotation of the spins away from the principal b axis, and they determine that the rotation is toward the a axis...

  19. Spin lattices of walking droplets

    Science.gov (United States)

    Saenz, Pedro; Pucci, Giuseppe; Goujon, Alexis; Dunkel, Jorn; Bush, John

    2017-11-01

    We present the results of an experimental investigation of the spontaneous emergence of collective behavior in spin lattice of droplets walking on a vibrating fluid bath. The bottom topography consists of relatively deep circular wells that encourage the walking droplets to follow circular trajectories centered at the lattice sites, in one direction or the other. Wave-mediated interactions between neighboring drops are enabled through a thin fluid layer between the wells. The sense of rotation of the walking droplets may thus become globally coupled. When the coupling is sufficiently strong, interactions with neighboring droplets may result in switches in spin that lead to preferred global arrangements, including correlated (all drops rotating in the same direction) or anti-correlated (neighboring drops rotating in opposite directions) states. Analogies with ferromagnetism and anti-ferromagnetism are drawn. Different spatial arrangements are presented in 1D and 2D lattices to illustrate the effects of topological frustration. This work was supported by the US National Science Foundation through Grants CMMI-1333242 and DMS-1614043.

  20. Rotational Osteotomy for Hallux Valgus. A New Technique for Primary and Revision Cases

    Science.gov (United States)

    Ortiz, Cristian; Wagner, Emilio

    2017-01-01

    More than 200 different surgical techniques exist for hallux valgus (HV). Some of them are designed for mild, moderate, or severe deformities depending on their correction power. Nevertheless, they all correct only the coronal and/or sagittal plane deformity. Just a handful of them correct the known axial malrotation that exists in most HV cases. This malrotation is one possible factor that could be the source of recurrence of an operated HV as it has been described. We describe a new technique which simultaneously corrects the metatarsal internal rotation and varus deformity by rotating the metatarsal through an oblique plane osteotomy. This is performed with no bone wedge resection. Also, there is a broader bone surface contact than on a transverse proximal osteotomy. This technique is easy to remember and relatively simple to perform in primary and revision cases. The authors results show that it is as safe and effective as other procedures, with some advantages to be discussed. Levels of Evidence: Diagnostic Level 5. See Instructions for Authors for a complete description of levels of evidence. PMID:28286430

  1. Evaluation of the functional results after rotator cuff arthroscopic repair with the suture bridge technique

    Directory of Open Access Journals (Sweden)

    Alberto Naoki Miyazaki

    Full Text Available ABSTRACT OBJECTIVE: To evaluate the results of arthroscopic treatment of large and extensive rotator cuff injuries (RCI that involved the supra and infraspinatus muscles using the suture bridge (SB technique. METHODS: Between July 2010 and November 2014, 37 patients with RCI who were treated with SB technique were evaluated. The study included all patients with a minimum follow-up of 12 months who underwent primary surgery of the shoulder. Twenty-four patients were male and 13 were female. The mean age was 60 years (45-75. The dominant side was affected in 32 cases. The most common cause of injury was trauma (18 cases. The mean preoperative motion was 123°, 58°, T11. Through magnetic resonance imaging, 36 fatty degenerations were classified according to Goutallier. Patients underwent rotator cuff repair with SB technique, which consists of using a medial row anchor with two Corkscrew(r fibertape(r or fiberwire(r at the articular margin, associated with lateral fixation without stitch using PushLocks(r or SwiveLocks(r. RESULTS: The mean age was 60 years and mean fatty degeneration was 2.6. The mean range of motion (following the AAOS in the postoperative evaluation was 148° of forward elevation, 55° in lateral rotation and medial rotation in T9. Using the criteria of the University of California at Los Angeles (UCLA, 35 (94% patients had excellent and good results; one (2.7%, fair; and one (2.7%, poor. CONCLUSION: Arthroscopic repair of a large and extensive RCI using SB technique had good and excellent results in 94% of the patients.

  2. Interfacial spin-orbit splitting and current-driven spin torque in anisotropic tunnel junctions

    KAUST Repository

    Manchon, Aurelien

    2011-01-01

    be generated at the second order in SOI, even in the absence of an external spin polarizer. This torque possesses two components, one in plane and one perpendicular to the plane of rotation, that can induce either current-driven magnetization switching from

  3. Edge rotational magnons in magnonic crystals

    International Nuclear Information System (INIS)

    Lisenkov, Ivan; Kalyabin, Dmitry; Nikitov, Sergey

    2013-01-01

    It is predicted that in 2D magnonic crystals the edge rotational magnons of forward volume magnetostatic spin waves can exist. Under certain conditions, locally bounded magnons may appear within the crystal consisting of the ferromagnetic matrix and periodically inserted magnetic/non-magnetic inclusions. It is also shown that interplay of different resonances in 2D magnonic crystal may provide conditions for spin wave modes existence with negative group velocity

  4. IMPACT CRATERING ON MERCURY: CONSEQUENCES FOR THE SPIN EVOLUTION

    Energy Technology Data Exchange (ETDEWEB)

    Correia, Alexandre C. M. [Department of Physics, I3N, University of Aveiro, Campus de Santiago, 3810-193 Aveiro (Portugal); Laskar, Jacques, E-mail: correia@ua.pt [ASD, IMCCE-CNRS UMR8028, Observatoire de Paris, UPMC, 77 Av. Denfert-Rochereau, 75014 Paris (France)

    2012-06-01

    Impact basins identified by Mariner 10 and Messenger flyby images provide us with a fossilized record of the impactor flux of asteroids on Mercury during the last stages of the early solar system. The distribution of these basins is not uniform across the surface and is consistent with a primordial synchronous rotation. By analyzing the size of the impacts, we derive a simple collisional model coherent with the observations. When combining it with the secular evolution of the spin of Mercury, we are able to reproduce the present 3/2 spin-orbit resonance ({approx}50% of chances), as well as a primordial synchronous rotation. This result is robust with respect to variations in the dissipation and collisional models, or in the initial spin state of the planet.

  5. IMPACT CRATERING ON MERCURY: CONSEQUENCES FOR THE SPIN EVOLUTION

    International Nuclear Information System (INIS)

    Correia, Alexandre C. M.; Laskar, Jacques

    2012-01-01

    Impact basins identified by Mariner 10 and Messenger flyby images provide us with a fossilized record of the impactor flux of asteroids on Mercury during the last stages of the early solar system. The distribution of these basins is not uniform across the surface and is consistent with a primordial synchronous rotation. By analyzing the size of the impacts, we derive a simple collisional model coherent with the observations. When combining it with the secular evolution of the spin of Mercury, we are able to reproduce the present 3/2 spin-orbit resonance (∼50% of chances), as well as a primordial synchronous rotation. This result is robust with respect to variations in the dissipation and collisional models, or in the initial spin state of the planet.

  6. Subscapularis slide correction of the shoulder internal rotation contracture after brachial plexus birth injury: technique and outcomes.

    Science.gov (United States)

    Immerman, Igor; Valencia, Herbert; DiTaranto, Patricia; DelSole, Edward M; Glait, Sergio; Price, Andrew E; Grossman, John A I

    2013-03-01

    Internal rotation contracture is the most common shoulder deformity in patients with brachial plexus birth injury. The purpose of this investigation is to describe the indications, technique, and results of the subscapularis slide procedure. The technique involves the release of the subscapularis muscle origin off the scapula, with preservation of anterior shoulder structures. A standard postoperative protocol is used in all patients and includes a modified shoulder spica with the shoulder held in 60 degrees of external rotation and 30 degrees of abduction, aggressive occupational and physical therapy, and subsequent shoulder manipulation under anesthesia with botulinum toxin injections as needed. Seventy-one patients at 2 institutions treated with subscapularis slide between 1997 and 2010, with minimum follow-up of 39.2 months, were identified. Patients were divided into 5 groups based on the index procedure performed: subscapularis slide alone (group 1); subscapularis slide with a simultaneous microsurgical reconstruction (group 2); primary microsurgical brachial plexus reconstruction followed later by a subscapularis slide (group 3); primary microsurgical brachial plexus reconstruction followed later by a subscapularis slide combined with tendon transfers for shoulder external rotation (group 4); and subscapularis slide with simultaneous tendon transfers, with no prior brachial plexus surgery (group 5). Full passive external rotation equivalent to the contralateral side was achieved in the operating room in all cases. No cases resulted in anterior instability or internal rotation deficit. Internal rotation contracture of the shoulder after brachial plexus birth injury can be effectively managed with the technique of subscapularis slide.

  7. Solid state {sup 1}H spin-lattice relaxation and isolated-molecule and cluster electronic structure calculations in organic molecular solids: The relationship between structure and methyl group and t-butyl group rotation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xianlong, E-mail: WangXianlong@uestc.edu.cn, E-mail: pbeckman@brynmawr.edu [Key Laboratory for NeuroInformation of Ministry of Education, School of Life Science and Technology, University of Electronic Science and Technology of China, 4 North Jianshe Rd., 2nd Section, Chengdu 610054 (China); Mallory, Frank B. [Department of Chemistry, Bryn Mawr College, 101 North Merion Ave., Bryn Mawr, Pennsylvania 19010-2899 (United States); Mallory, Clelia W. [Department of Chemistry, Bryn Mawr College, 101 North Merion Ave., Bryn Mawr, Pennsylvania 19010-2899 (United States); Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323 (United States); Odhner, Hosanna R.; Beckmann, Peter A., E-mail: WangXianlong@uestc.edu.cn, E-mail: pbeckman@brynmawr.edu [Department of Physics, Bryn Mawr College, 101 North Merion Ave., Bryn Mawr, Pennsylvania 19010-2899 (United States)

    2014-05-21

    We report ab initio density functional theory electronic structure calculations of rotational barriers for t-butyl groups and their constituent methyl groups both in the isolated molecules and in central molecules in clusters built from the X-ray structure in four t-butyl aromatic compounds. The X-ray structures have been reported previously. We also report and interpret the temperature dependence of the solid state {sup 1}H nuclear magnetic resonance spin-lattice relaxation rate at 8.50, 22.5, and 53.0 MHz in one of the four compounds. Such experiments for the other three have been reported previously. We compare the computed barriers for methyl group and t-butyl group rotation in a central target molecule in the cluster with the activation energies determined from fitting the {sup 1}H NMR spin-lattice relaxation data. We formulate a dynamical model for the superposition of t-butyl group rotation and the rotation of the t-butyl group's constituent methyl groups. The four compounds are 2,7-di-t-butylpyrene, 1,4-di-t-butylbenzene, 2,6-di-t-butylnaphthalene, and 3-t-butylchrysene. We comment on the unusual ground state orientation of the t-butyl groups in the crystal of the pyrene and we comment on the unusually high rotational barrier of these t-butyl groups.

  8. Generalized Faraday law derived from classical forces in a rotating frame

    International Nuclear Information System (INIS)

    Choi, Taeseung

    2010-01-01

    We show that an additional spin-dependent classical force due to the rotation of an electron spin's rest frame is essential to derive a spin-Faraday law that has the same form as the usual Faraday law. We show that the contribution of the additional spin-dependent force to the spin-Faraday law is the same as the time derivative of the spin geometric phase. With this observations, the spin-Faraday law is generalized to include both an Aharonov-Casher (AC) effect and a scalar AC effect in a unified manner.

  9. Numerical simulation of 3D unsteady flow in a rotating pump by dynamic mesh technique

    International Nuclear Information System (INIS)

    Huang, S; Guo, J; Yang, F X

    2013-01-01

    In this paper, the numerical simulation of unsteady flow for three kinds of typical rotating pumps, roots blower, roto-jet pump and centrifugal pump, were performed using the three-dimensional Dynamic Mesh technique. In the unsteady simulation, all the computational domains, as stationary, were set in one inertial reference frame. The motions of the solid boundaries were defined by the Profile file in FLUENT commercial code, in which the rotational orientation and speed of the rotors were specified. Three methods (Spring-based Smoothing, Dynamic Layering and Local Re-meshing) were used to achieve mesh deformation and re-meshing. The unsteady solutions of flow field and pressure distribution were solved. After a start-up stage, the flow parameters exhibit time-periodic behaviour corresponding to blade passing frequency of rotor. This work shows that Dynamic Mesh technique could achieve numerical simulation of three-dimensional unsteady flow field in various kinds of rotating pumps and have a strong versatility and broad application prospects

  10. The effects of spin in gases

    International Nuclear Information System (INIS)

    Laloee, F.; Freed, J.H.

    1988-01-01

    Low-density gases, in which atoms are separated by large distances, have long provided an enjoyable playground for physicists. One might suppose the pleasure of the playground would by now have been exhausted by the very simplicity of low-density gases. Recent work by a number of investigators including the author shows that this is not the case low-density gases continue to serve up a rich variety of phenomena as well as counterintuitive surprises. In particular, the macroscopic properties of a gas composed of individual hydrogen or helium atoms can under special circumstances by changed dramatically by quantum-mechanical effects. According to quantum theory, the nucleus of an atom behaves in a way similar to a rotating top, which has angular momentum about its axis of rotation; that is, the nucleus has spin, known more precisely as spin angular momentum. If the atoms of a gas are spin-polarized, so that their nuclei all have their spins pointing in the same direction, the viscosity of the gas can be changed enormously and so can its ability to conduct heat. Quantum-mechanical correlations among the nuclei called spin waves, which up to now had been observed only in certain liquids and solids such as magnets, can also arise. The changes are large enough for one to say the quantum-mechanical effects have caused the gas to take on entirely new properties. In a certain sense it is amazing to think that polarizing the nuclear spins can have any effect on the macroscopic properties of the gas, since the nuclear spins are son weakly coupled to the outside world. Yet the observations are in full agreement with with theory. Moreover, because spin-polarized gases are still fairly simple systems, they can be understood in terms fundamental principles, something that is still not possible to do in the case of liquids and solids

  11. The kinematic differences between off-spin and leg-spin bowling in cricket.

    Science.gov (United States)

    Beach, Aaron J; Ferdinands, René E D; Sinclair, Peter J

    2016-09-01

    Spin bowling is generally coached using a standard technical framework, but this practice has not been based upon a comparative biomechanical analysis of leg-spin and off-spin bowling. This study analysed the three-dimensional (3D) kinematics of 23 off-spin and 20 leg-spin bowlers using a Cortex motion analysis system to identify how aspects of the respective techniques differed. A multivariate ANOVA found that certain data tended to validate some of the stated differences in the coaching literature. Off-spin bowlers had a significantly shorter stride length (p = 0.006) and spin rate (p = 0.001), but a greater release height than leg-spinners (p = 0.007). In addition, a number of other kinematic differences were identified that were not previously documented in coaching literature. These included a larger rear knee flexion (p = 0.007), faster approach speed (p < 0.001), and flexing elbow action during the arm acceleration compared with an extension action used by most of the off-spin bowlers. Off-spin and leg-spin bowlers also deviated from the standard coaching model for the shoulder alignment, front knee angle at release, and forearm mechanics. This study suggests that off-spin and leg-spin are distinct bowling techniques, supporting the development of two different coaching models in spin bowling.

  12. Eating a planet and spinning up

    Science.gov (United States)

    Qureshi, Ahmed; Naoz, Smadar; Shkolnik, Evgenya L.

    2018-01-01

    One of the predictions of high eccentricity planetary migration is that many planets will end up plunging into their host stars. We investigate the consequence of planetary mergers on their stellar hosts’ spin-period. Energy and angular momentum conservation yield that a planet consumption by a star will spin-up of the star. We find that our calculations align with the observed bifurcation in the stellar spin-period in young clusters. After a Sun-like star has eaten a planet, it will then, spin down due to magnetic braking, consistent with the observed lack of fast rotators in old clusters. The agreement between the calculations presented here and the observed spin-period of stars in young clusters provides circumstantial evidence that planetary accretion onto their host stars is a generic feature in planetary-system evolution.

  13. Influence of Rotator Cuff Tear Size and Repair Technique on the Creation and Management of Dog Ear Deformities in a Transosseous-Equivalent Rotator Cuff Repair Model

    Science.gov (United States)

    Redler, Lauren H.; Byram, Ian R.; Luchetti, Timothy J.; Tsui, Ying Lai; Moen, Todd C.; Gardner, Thomas R.; Ahmad, Christopher S.

    2014-01-01

    Background: Redundancies in the rotator cuff tissue, commonly referred to as “dog ear” deformities, are frequently encountered during rotator cuff repair. Knowledge of how these deformities are created and their impact on rotator cuff footprint restoration is limited. Purpose: The goals of this study were to assess the impact of tear size and repair method on the creation and management of dog ear deformities in a human cadaveric model. Study Design: Controlled laboratory study. Methods: Crescent-shaped tears were systematically created in the supraspinatus tendon of 7 cadaveric shoulders with increasing medial to lateral widths (0.5, 1.0, and 1.5 cm). Repair of the 1.5-cm tear was performed on each shoulder with 3 methods in a randomized order: suture bridge, double-row repair with 2-mm fiber tape, and fiber tape with peripheral No. 2 nonabsorbable looped sutures. Resulting dog ear deformities were injected with an acrylic resin mixture, digitized 3-dimensionally (3D), and photographed perpendicular to the footprint with calibration. The volume, height, and width of the rotator cuff tissue not in contact with the greater tuberosity footprint were calculated using the volume injected, 3D reconstructions, and calibrated photographs. Comparisons were made between tear size, dog ear measurement technique, and repair method utilizing 2-way analysis of variance and Student-Newman-Keuls multiple-comparison tests. Results: Utilizing 3D digitized and injection-derived volumes and dimensions, anterior dog ear volume, height, and width were significantly smaller for rotator cuff repair with peripheral looped sutures compared with a suture bridge (P repair with 2-mm fiber tape alone (P repair with looped peripheral sutures compared with a suture bridge (P repair technique, peripheral No. 2 nonabsorbable looped sutures significantly decreased the volume, height, and width of dog ear deformities, better restoring the anatomic footprint of the rotator cuff. Clinical

  14. Computer modeling of the dynamics of surface tension on rotating fluids in low and microgravity environments

    Science.gov (United States)

    Hung, R. J.; Tsao, Y. D.; Hong, B. B.; Leslie, Fred W.

    1989-01-01

    Time-dependent evolutions of the profile of the free surface (bubble shapes) for a cylindrical container partially filled with a Newtonian fluid of constant density, rotating about its axis of symmetry, have been studied. Numerical computations have been carried out with the following situations: (1) linear functions of spin-up and spin-down in low- and microgravity environments, (2) linear functions of increasing and decreasing gravity environments at high- and low-rotating cylinder speeds, and (3) step functions of spin-up and spin-down in a low-gravity environment.

  15. Spin-flip tunneling in quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Schreiber, Lars; Braakman, Floris; Meunier, Tristan; Calado, Victor; Vandersypen, Lieven [Kavli Institute of NanoScience, Delft (Netherlands); Wegscheider, Werner [Institute for Experimental and Applied Physics, University of Regensburg (Germany)

    2010-07-01

    Electron spins in a gate-defined double quantum dot formed in a GaAs/(Al,Ga)As 2DEG are promising candidates for quantum information processing as coherent single spin rotation and spin swap has been demonstrated recently. In this system we investigate the two-electron spin dynamics in the presence of microwaves (5.20 GHz) applied to one side gate. During microwave excitation we observe characteristic photon assisted tunneling (PAT) peaks at the (1,1) to (0,2) charge transition. Some of the PAT peaks are attributed to photon tunneling events between the singlet S(0,2) and the singlet S(1,1) states, a spin-conserving transition. Surprisingly, other PAT peaks stand out by their different external magnetic field dependence. They correspond to tunneling involving a spin-flip, from the (0,2) singlet to a (1,1) triplet. The full spectrum of the observed PAT lines is captured by simulations. This process offers novel possibilities for 2-electron spin manipulation and read-out.

  16. Effect of Orbital Hybridization on Spin-Polarized Tunneling across Co/C60 Interfaces.

    Science.gov (United States)

    Wang, Kai; Strambini, Elia; Sanderink, Johnny G M; Bolhuis, Thijs; van der Wiel, Wilfred G; de Jong, Michel P

    2016-10-26

    The interaction between ferromagnetic surfaces and organic semiconductors leads to the formation of hybrid interfacial states. As a consequence, the local magnetic moment is altered, a hybrid interfacial density of states (DOS) is formed, and spin-dependent shifts of energy levels occur. Here, we show that this hybridization affects spin transport across the interface significantly. We report spin-dependent electronic transport measurements for tunnel junctions comprising C 60 molecular thin films grown on top of face-centered-cubic (fcc) epitaxial Co electrodes, an AlO x tunnel barrier, and an Al counter electrode. Since only one ferromagnetic electrode (Co) is present, spin-polarized transport is due to tunneling anisotropic magnetoresistance (TAMR). An in-plane TAMR ratio of approximately 0.7% has been measured at 5 K under application of a magnetic field of 800 mT. The magnetic switching behavior shows some remarkable features, which are attributed to the rotation of interfacial magnetic moments. This behavior can be ascribed to the magnetic coupling between the Co thin films and the newly formed Co/C 60 hybridized interfacial states. Using the Tedrow-Meservey technique, the tunnel spin polarization of the Co/C 60 interface was found to be 43%.

  17. Patch-augmented rotator cuff repair: influence of the patch fixation technique on primary biomechanical stability.

    Science.gov (United States)

    Jung, Christian; Spreiter, Gregor; Audigé, Laurent; Ferguson, Stephen J; Flury, Matthias

    2016-05-01

    There is an ongoing debate about the potential of patch augmentation to improve biomechanical stability and healing associated with rotator cuff repair. The biomechanical properties of three different patch-augmented rotator cuff repair techniques were assessed in vitro and compared with a standard repair. Dermal collagen patch augmentation may increase the primary stability and strength of the repaired tendon in vitro, depending on the technique used for patch application. Forty cadaveric sheep shoulders with dissected infraspinatus tendons were randomized into four groups (n = 10/group) for tendon repair using a knotless double-row suture anchor technique. A xenologous dermal extracellular matrix patch was used for augmentation in the three test groups using an "integrated", "cover", or "hybrid" technique. Tendons were preconditioned, cyclically loaded from 10 to 30 N at 1 Hz, and then loaded monotonically to failure. Biomechanical properties and the mode of failure were evaluated. Patch augmentation significantly increased the maximum load at failure by 61 % in the "cover" technique test group (225.8 N) and 51 % in the "hybrid" technique test group (211.4 N) compared with the non-augmented control group (140.2 N) (P ≤ 0.015). For the test group with "integrated" patch augmentation, the load at failure was 28 % lower (101.6 N) compared with the control group (P = 0.043). There was no significant difference in initial and linear stiffness among the four experimental groups. The most common mode of failure was tendon pullout. No anchor dislocation, patch disruption or knot breakage was observed. Additional patch augmentation with a collagen patch influences the biomechanical properties of a rotator cuff repair in a cadaveric sheep model. Primary repair stability can be significantly improved depending on the augmentation technique.

  18. Evolution of nuclear shapes at high spins

    International Nuclear Information System (INIS)

    Johnson, N.R.

    1985-01-01

    The dynamic electric quadrupole (E2) moments are a direct reflection of the collective aspects of the nuclear wave functions. For this, Doppler-shift lifetime measurements have been done utilizing primarily the recoil-distance technique. The nuclei with neutron number N approx. 90 possess many interesting properties. These nuclei have very shallow minima in their potential energy surfaces, and thus, are very susceptible to deformation driving influences. It is the evolution of nuclear shapes as a function of spin or rotational frequency for these nuclei that has commanded much interest in the lifetime measurements discussed here. There is growing evidence that many deformed nuclei which have prolate shapes in their ground states conform to triaxial or oblate shapes at higher spins. Since the E2 matrix elements along the yrast line are sensitive indicators of deformation changes, measurements of lifetimes of these states to provide the matrix elements has become the major avenue for tracing the evolving shape of a nucleus at high spin. Of the several nuclei we have studied with N approx. 90, those to be discussed here are /sup 160,161/Yb and 158 Er. In addition, the preliminary, but interesting and surprising results from our recent investigation of the N = 98 nucleus, 172 W are briefly discussed. 14 refs., 5 figs

  19. RACE-OC project: Rotation and variability of young stellar associations within 100 pc

    Science.gov (United States)

    Messina, S.; Desidera, S.; Turatto, M.; Lanzafame, A. C.; Guinan, E. F.

    2010-09-01

    Context. Examining the angular momentum of stars and its interplay with their magnetic fields represent a promising way to probe the stellar internal structure and evolution of low-mass stars. Aims: We attempt to determine the rotational and magnetic-related activity properties of stars at different stages of evolution.We focused our attention primarily on members of clusters and young stellar associations of known ages. In this study, our targets are 6 young loose stellar associations within 100 pc and with ages in the range 8-70 Myr: TW Hydrae (~8 Myr), β Pictoris (~10 Myr), Tucana/Horologium, Columba, Carina (~30 Myr), and AB Doradus (~70 Myr). Additional rotational data for α Persei and the Pleiades from the literature are also considered. Methods: Rotational periods of stars exhibiting rotational modulation due to photospheric magnetic activity (i.e., starspots) were determined by applying the Lomb-Scargle periodogram technique to photometric time-series data obtained by the All Sky Automated Survey (ASAS). The magnetic activity level was derived from the amplitude of the V lightcurves. The statistical significance of the rotational evolution at different ages was inferred by applying a two-sided Kolmogorov-Smirnov test to subsequent age-bins. Results: We detected the rotational modulation and measured the rotation periods of 93 stars for the first time, and confirmed the periods of 41 stars already known from the literature. For an additional 10 stars, we revised the period determinations by other authors. The sample was augmented with periods of 21 additional stars retrieved from the literature. In this way, for the first time we were able to determine the largest set of rotation periods at ages of ~8, ~10 and ~30 Myr, as well as increase by 150% the number of known periodic members of AB Dor. Conclusions: The analysis of the rotation periods in young stellar associations, supplemented by Orion Nebula Cluster (ONC) and NGC 2264 data from the literature

  20. Solid state NMR, basic theory and recent progress for quadrupole nuclei with half-integer spin

    International Nuclear Information System (INIS)

    Dieter, F.

    1998-01-01

    This review describes the basic theory and some recently developed techniques for the study of quadrupole nuclei with half integer spins in powder materials. The latter is connected to the introduction of the double rotation (DOR) by A. Samoson et al. (1) and to the introduction of the multiple quantum magic-angle spinning (MQ MAS) technique by L. Frydman et. al. (2). For integer spins, especially the solid-state deuterium magnetic resonance, we refer to the review of G.L. Hoatson and R.L. Vold: '' 2 H-NMR Spectroscopy of Solids and Liquid Crystals'' (3). For single crystals we refer to O. Kanert and M. Mehring: ''Static quadrupole effects in disordered cubic solids''(4) and we would like also to mention the ''classic'' review of M.H. Cohen and F. Reif: ''Quadrupole effects in NMR studies of solids'' (5). Some more recent reviews in the field under study are D. Freude and J. Haase ''Quadrupole effects in solid-state NMR'' (6). Ch. Jager: ''Satellite Transition Spectroscopy of Quadrupolar Nuclei'' (7) and B.F. Chmelka and J.W. Zwanziger: ''Solid State NMR Line Narrowing Methods for Quadrupolar Nuclei - Double Rotation and Dynamic-Angle Spinning'' (8). A survey of nuclear quadrupole frequency data published before the end of 1982 is given by H. Chihara and N. Nakamura in Landolt-Bornstein, Vol. 20 (9). Values of the chemical shift of quadrupole nuclei in solids can be found in books such as ''Multinuclear NMR'' edited by J. Mason (10). In section 9 of ref (6) some electric field gradient and chemical shift data published from 1983 to 1992 for the most studied quadrupole nuclei sup 27 Al, sup 23 Na, and sup 17 O are given

  1. Field control of anisotropic spin transport and spin helix dynamics in a modulation-doped GaAs quantum well

    Science.gov (United States)

    Anghel, S.; Passmann, F.; Singh, A.; Ruppert, C.; Poshakinskiy, A. V.; Tarasenko, S. A.; Moore, J. N.; Yusa, G.; Mano, T.; Noda, T.; Li, X.; Bristow, A. D.; Betz, M.

    2018-03-01

    Electron spin transport and dynamics are investigated in a single, high-mobility, modulation-doped, GaAs quantum well using ultrafast two-color Kerr-rotation microspectroscopy, supported by qualitative kinetic theory simulations of spin diffusion and transport. Evolution of the spins is governed by the Dresselhaus bulk and Rashba structural inversion asymmetries, which manifest as an effective magnetic field that can be extracted directly from the experimental coherent spin precession. A spin-precession length λSOI is defined as one complete precession in the effective magnetic field. It is observed that application of (i) an out-of-plane electric field changes the spin decay time and λSOI through the Rashba component of the spin-orbit coupling, (ii) an in-plane magnetic field allows for extraction of the Dresselhaus and Rashba parameters, and (iii) an in-plane electric field markedly modifies both the λSOI and diffusion coefficient.

  2. Spin at Lausanne

    International Nuclear Information System (INIS)

    Anon.

    1980-01-01

    From 25 September to 1 October, some 150 spin enthusiasts gathered in Lausanne for the 1980 International Symposium on High Energy Physics with Polarized Beams and Polarized Targets. The programme was densely packed, covering physics interests with spin as well as the accelerator and target techniques which make spin physics possible

  3. MR alterations of the rotator cuff and anterior gienold labrum

    International Nuclear Information System (INIS)

    Kjellin, I.; Ho, C.; Haghighi, P.; Kerr, R.; Trudell, D.; Cervilla, V.; Resnick, D.

    1990-01-01

    This paper determines the histopathologic causes of alterations in signal and morphology in the tendinous rotator cuff and glenoid labrum on shoulder MR images. MR imaging was performed in 13 cadaveric shoulders. Coronal oblique imaging of the rotator cuff was performed with spin-echo sequences (TR 2,000; TE 25/80). The labrum was examined with transaxial spin-echo, fat-suppression (HYBRID), and MPGR sequences. The shoulders then were frozen and sectioned at 3-mm intervals in the plane of interest. Areas corresponding to sites of MR alterations were examined histologically

  4. Manifest rotation symmetric expressions for angular momentum eigenfunctions

    International Nuclear Information System (INIS)

    Eeg, J.O.; Wroldsen, J.

    1983-01-01

    Manifest rotation symmetric expressions for eigenfunctions for spin s, orbital angular momentum l and total angular momentum j = l+s, .... , /l-s/ in terms of (2j+1) x (2s+1) multipole transition matrices (MTM) is given. These matrices, which are irreducible tensor matrices, have an algebra together with ordinary spin matrices for spin s and spin j. Explicit expressions for MTM's and their algebra are given for angular momenta <-3. By means of some examples it is shown that within this formalism angular integrations in central field problems will be simplified considerably. Thus the formalism turns out to be very useful for instance for calculations within the MIT-bag and also within spin-spin interactions in atomic physics. (Auth.)

  5. Spin-polarized photoemission

    International Nuclear Information System (INIS)

    Johnson, Peter D.

    1997-01-01

    Spin-polarized photoemission has developed into a versatile tool for the study of surface and thin film magnetism. In this review, we examine the methodology of the technique and its application to a number of different problems, including both valence band and core level studies. After a detailed review of spin-polarization measurement techniques and the related experimental requirements we consider in detail studies of the bulk properties both above and below the Curie temperature. This section also includes a discussion of observations relating to unique metastable phases obtained via epitaxial growth. The application of the technique to the study of surfaces, both clean and adsorbate covered, is reviewed. The report then examines, in detail, studies of the spin-polarized electronic structure of thin films and the related interfacial magnetism. Finally, observations of spin-polarized quantum well states in non-magnetic thin films are discussed with particular reference to their mediation of the oscillatory exchange coupling in related magnetic multilayers. (author)

  6. Piezoelectric Vibration Damping Study for Rotating Composite Fan Blades

    Science.gov (United States)

    Min, James B.; Duffy, Kirsten P.; Choi, Benjamin B.; Provenza, Andrew J.; Kray, Nicholas

    2012-01-01

    Resonant vibrations of aircraft engine blades cause blade fatigue problems in engines, which can lead to thicker and aerodynamically lower performing blade designs, increasing engine weight, fuel burn, and maintenance costs. In order to mitigate undesirable blade vibration levels, active piezoelectric vibration control has been investigated, potentially enabling thinner blade designs for higher performing blades and minimizing blade fatigue problems. While the piezoelectric damping idea has been investigated by other researchers over the years, very little study has been done including rotational effects. The present study attempts to fill this void. The particular objectives of this study were: (a) to develop and analyze a multiphysics piezoelectric finite element composite blade model for harmonic forced vibration response analysis coupled with a tuned RLC circuit for rotating engine blade conditions, (b) to validate a numerical model with experimental test data, and (c) to achieve a cost-effective numerical modeling capability which enables simulation of rotating blades within the NASA Glenn Research Center (GRC) Dynamic Spin Rig Facility. A numerical and experimental study for rotating piezoelectric composite subscale fan blades was performed. It was also proved that the proposed numerical method is feasible and effective when applied to the rotating blade base excitation model. The experimental test and multiphysics finite element modeling technique described in this paper show that piezoelectric vibration damping can significantly reduce vibrations of aircraft engine composite fan blades.

  7. Dynamical scaling in polymer solutions investigated by the neutron spin echo technique

    International Nuclear Information System (INIS)

    Richter, D.; Ewen, B.

    1979-01-01

    Chain dynamics in polymer solutions was investigated by means of the recently developed neutron spin echo spectroscopy. - By this technique, it was possible for the first time to verify unambiguously the scaling predictions of the Zimm model in the case of single chain behaviour and to observe the cross over to many chain behaviour. The segmental diffusion of single chains exhibits deviations from a simple exponential law, indicating the importance of memory effects. (orig.) [de

  8. SPIN EVOLUTION OF ACCRETING YOUNG STARS. II. EFFECT OF ACCRETION-POWERED STELLAR WINDS

    International Nuclear Information System (INIS)

    Matt, Sean P.; Pinzón, Giovanni; Greene, Thomas P.; Pudritz, Ralph E.

    2012-01-01

    We present a model for the rotational evolution of a young, solar-mass star interacting magnetically with an accretion disk. As in a previous paper (Paper I), the model includes changes in the star's mass and radius as it descends the Hayashi track, a decreasing accretion rate, and a prescription for the angular momentum transfer between the star and disk. Paper I concluded that, for the relatively strong magnetic coupling expected in real systems, additional processes are necessary to explain the existence of slowly rotating pre-main-sequence stars. In the present paper, we extend the stellar spin model to include the effect of a spin-down torque that arises from an accretion-powered stellar wind (APSW). For a range of magnetic field strengths, accretion rates, initial spin rates, and mass outflow rates, the modeled stars exhibit rotation periods within the range of 1-10 days in the age range of 1-3 Myr. This range coincides with the bulk of the observed rotation periods, with the slow rotators corresponding to stars with the lowest accretion rates, strongest magnetic fields, and/or highest stellar wind mass outflow rates. We also make a direct, quantitative comparison between the APSW scenario and the two types of disk-locking models (namely, the X-wind and Ghosh and Lamb type models) and identify some remaining theoretical issues for understanding young star spins.

  9. Relaxation processes in rotational motion

    International Nuclear Information System (INIS)

    Broglia, R.A.

    1986-01-01

    At few MeV above the yrast line the normally strong correlations among γ-ray energies in a rotational sequence become weaker. This observation can be interpreted as evidence for the damping of rotational motion in hot nuclei. It seems possible to relate the spreading width of the E2-rotational decay strength to the spread in frequency Δω 0 of rotational bands. The origin of these fluctuations is found in: (1) fluctuations in the occupation of special single-particle orbits which contribute a significant part of the total angular momentum; and (2) fluctuations in the moment of inertia induced by vibrations of the nuclear shape. Estimates of Δω 0 done making use of the hundred-odd known discrete rotational bands in the rare-earth region lead, for moderate spin and excitation energies (I ≅ 30 and U ≅ 3 to 4 MeV), to rotational spreading widths of the order of 60 to 160 keV in overall agreement with the data. 24 refs

  10. Accelerating proton spin diffusion in perdeuterated proteins at 100 kHz MAS

    Energy Technology Data Exchange (ETDEWEB)

    Wittmann, Johannes J.; Agarwal, Vipin; Hellwagner, Johannes; Lends, Alons; Cadalbert, Riccardo; Meier, Beat H., E-mail: beme@ethz.ch; Ernst, Matthias, E-mail: maer@ethz.ch [ETH Zurich, Physical Chemistry (Switzerland)

    2016-12-15

    Fast magic-angle spinning (>60 kHz) has many advantages but makes spin-diffusion-type proton–proton long-range polarization transfer inefficient and highly dependent on chemical-shift offset. Using 100%-HN-[{sup 2}H,{sup 13}C,{sup 15}N]-ubiquitin as a model substance, we quantify the influence of the chemical-shift difference on the spin diffusion between proton spins and compare two experiments which lead to an improved chemical-shift compensation of the transfer: rotating-frame spin diffusion and a new experiment, reverse amplitude-modulated MIRROR. Both approaches enable broadband spin diffusion, but the application of the first variant is limited due to fast spin relaxation in the rotating frame. The reverse MIRROR experiment, in contrast, is a promising candidate for the determination of structurally relevant distance restraints. The applied tailored rf-irradiation schemes allow full control over the range of recoupled chemical shifts and efficiently drive spin diffusion. Here, the relevant relaxation time is the larger longitudinal relaxation time, which leads to a higher signal-to-noise ratio in the spectra.

  11. Propagator for a spin-Bose system with the Bose field coupled to a reservoir of harmonic oscillators

    CERN Document Server

    Banerjee, S

    2003-01-01

    We consider the general problem of a single two-level atom interacting with a multimode radiation field (without the rotating-wave approximation), and additionally take the field to be coupled to a thermal reservoir. Using the method of bosonization of the spin operators in the Hamiltonian, and working in the Bargmann representation for all the boson operators, we obtain the propagator for the composite system using the techniques of functional integration, under a reasonable approximation scheme. The propagator is explicitly evaluated for a simplified version of the system with one spin and a dynamically coupled single-mode field. The results are also checked on the known problem of quantum Brownian motion.

  12. ΔI = 2 Nuclear Staggering in Superdeformed Rotational Bands

    Directory of Open Access Journals (Sweden)

    Okasha M. D.

    2014-01-01

    Full Text Available A four parameters model including collective rotational en ergies to fourth order is ap- plied to reproduce the ∆ I = 2 staggering in transition energies in four selected super deformed rotational bands, namely, 148 Gd (SD6, 194 Hg (SD1, SD2, SD3. The model parameters and the spin of the bandhead have been extracted a ssuming various val- ues to the lowest spin of the bandhead at nearest integer, in o rder to obtain a minimum root mean square deviation between calculated and the exper imental transition energies. This allows us to suggest the spin values for the energy level s which are experimentally unknown. For each band a staggering parameter represent the deviation of the transition energies from a smooth reference has been determined by calc ulating the fourth order derivative of the transition energies at a given spin. The st aggering parameter contains five consecutive transition energies which is denoted here a s the five-point formula. In order to get information about the dynamical moment of ine rtia, the two point for- mula which contains only two consecutive transition energi es has been also considered. The dynamical moment of inertia decreasing with increasing rotational frequency for A ∼ 150, while increasing for A ∼ 190 mass regions.

  13. Accurate and efficient spin integration for particle accelerators

    Directory of Open Access Journals (Sweden)

    Dan T. Abell

    2015-02-01

    Full Text Available Accurate spin tracking is a valuable tool for understanding spin dynamics in particle accelerators and can help improve the performance of an accelerator. In this paper, we present a detailed discussion of the integrators in the spin tracking code gpuSpinTrack. We have implemented orbital integrators based on drift-kick, bend-kick, and matrix-kick splits. On top of the orbital integrators, we have implemented various integrators for the spin motion. These integrators use quaternions and Romberg quadratures to accelerate both the computation and the convergence of spin rotations. We evaluate their performance and accuracy in quantitative detail for individual elements as well as for the entire RHIC lattice. We exploit the inherently data-parallel nature of spin tracking to accelerate our algorithms on graphics processing units.

  14. Effect of a high-frequency magnetic field on the resonant behavior displayed by a spin-1/2 particle under the influence of a rotating magnetic field

    International Nuclear Information System (INIS)

    Casado-Pascual, Jesus

    2010-01-01

    Graphical abstract: In this paper, we investigate the role of a high-frequency magnetic field in the resonant behavior displayed by a spin-1/2 particle under the influence of a rotating magnetic field. We propose two alternative methods for analyzing the system dynamics, namely, the averaging method and the multiple scale method. - Abstract: In this paper, we investigate the role of a high-frequency magnetic field in the resonant behavior displayed by a spin-1/2 particle under the influence of a rotating magnetic field. We propose two alternative methods for analyzing the system dynamics, namely, the averaging method and the multiple scale method. The analytical results achieved by applying these two methods are compared with those obtained from the numerical solution of the Schroedinger equation. This comparison leads to the conclusion that the multiple scale method provides a better understanding of the system dynamics than the averaging method. In particular, the averaging method predicts the complete destruction of the resonant behavior by an appropriate choice of the parameter values of the high-frequency magnetic field. This conclusion is disproved both by the numerical results, and also by the results obtained from the multiple scale method.

  15. Arthroscopic suture bridge technique for intratendinous tear of rotator cuff in chronically painful calcific tendinitis of the shoulder.

    Science.gov (United States)

    Ji, Jong-Hun; Shafi, Mohamed; Moon, Chang-Yun; Park, Sang-Eun; Kim, Yeon-Jun; Kim, Sung-Eun

    2013-11-01

    Arthroscopic removal, now the main treatment option, has almost replaced open surgery for treatment of resistant calcific tendinitis. In some cases of chronic calcific tendinitis of the shoulder, the calcific materials are hard and adherent to the tendon. Removal of these materials can cause significant intratendinous tears between the superficial and deep layers of the degenerated rotator cuff. Thus far, there are no established surgical techniques for removing the calcific materials while ensuring cuff integrity. Good clinical results for rotator cuff repair were achieved by using an arthroscopic suture bridge technique in patients with long-standing calcific tendinitis. Intact rotator cuff integrity and recovery of signal change on follow-up magnetic resonance imaging scans were confirmed. This is a technical note about a surgical technique and its clinical results with a review of relevant published reports. © 2013 Chinese Orthopaedic Association and Wiley Publishing Asia Pty Ltd.

  16. Accurate and efficient spin integration for particle accelerators

    International Nuclear Information System (INIS)

    Abell, Dan T.; Meiser, Dominic; Ranjbar, Vahid H.; Barber, Desmond P.

    2015-01-01

    Accurate spin tracking is a valuable tool for understanding spin dynamics in particle accelerators and can help improve the performance of an accelerator. In this paper, we present a detailed discussion of the integrators in the spin tracking code GPUSPINTRACK. We have implemented orbital integrators based on drift-kick, bend-kick, and matrix-kick splits. On top of the orbital integrators, we have implemented various integrators for the spin motion. These integrators use quaternions and Romberg quadratures to accelerate both the computation and the convergence of spin rotations. We evaluate their performance and accuracy in quantitative detail for individual elements as well as for the entire RHIC lattice. We exploit the inherently data-parallel nature of spin tracking to accelerate our algorithms on graphics processing units.

  17. Accurate and efficient spin integration for particle accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Abell, Dan T.; Meiser, Dominic [Tech-X Corporation, Boulder, CO (United States); Ranjbar, Vahid H. [Brookhaven National Laboratory, Upton, NY (United States); Barber, Desmond P. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2015-01-15

    Accurate spin tracking is a valuable tool for understanding spin dynamics in particle accelerators and can help improve the performance of an accelerator. In this paper, we present a detailed discussion of the integrators in the spin tracking code GPUSPINTRACK. We have implemented orbital integrators based on drift-kick, bend-kick, and matrix-kick splits. On top of the orbital integrators, we have implemented various integrators for the spin motion. These integrators use quaternions and Romberg quadratures to accelerate both the computation and the convergence of spin rotations. We evaluate their performance and accuracy in quantitative detail for individual elements as well as for the entire RHIC lattice. We exploit the inherently data-parallel nature of spin tracking to accelerate our algorithms on graphics processing units.

  18. Modes of uncontrolled rotational motion of the Progress M-29M spacecraft

    Science.gov (United States)

    Belyaev, M. Yu.; Matveeva, T. V.; Monakhov, M. I.; Rulev, D. N.; Sazonov, V. V.

    2018-01-01

    We have reconstructed the uncontrolled rotational motion of the Progress M-29M transport cargo spacecraft in the single-axis solar orientation mode (the so-called sunward spin) and in the mode of the gravitational orientation of a rotating satellite. The modes were implemented on April 3-7, 2016 as a part of preparation for experiments with the DAKON convection sensor onboard the Progress spacecraft. The reconstruction was performed by integral statistical techniques using the measurements of the spacecraft's angular velocity and electric current from its solar arrays. The measurement data obtained in a certain time interval have been jointly processed using the least-squares method by integrating the equations of the spacecraft's motion relative to the center of mass. As a result of processing, the initial conditions of motion and parameters of the mathematical model have been estimated. The motion in the sunward spin mode is the rotation of the spacecraft with an angular velocity of 2.2 deg/s about the normal to the plane of solar arrays; the normal is oriented toward the Sun or forms a small angle with this direction. The duration of the mode is several orbit passes. The reconstruction has been performed over time intervals of up to 1 h. As a result, the actual rotational motion of the spacecraft relative to the Earth-Sun direction was obtained. In the gravitational orientation mode, the spacecraft was rotated about its longitudinal axis with an angular velocity of 0.1-0.2 deg/s; the longitudinal axis executed small oscillated relative to the local vertical. The reconstruction of motion relative to the orbital coordinate system was performed in time intervals of up to 7 h using only the angularvelocity measurements. The measurements of the electric current from solar arrays were used for verification.

  19. Friction spinning - Twist phenomena and the capability of influencing them

    Science.gov (United States)

    Lossen, Benjamin; Homberg, Werner

    2016-10-01

    The friction spinning process can be allocated to the incremental forming techniques. The process consists of process elements from both metal spinning and friction welding. The selective combination of process elements from these two processes results in the integration of friction sub-processes in a spinning process. This implies self-induced heat generation with the possibility of manufacturing functionally graded parts from tube and sheets. Compared with conventional spinning processes, this in-process heat treatment permits the extension of existing forming limits and also the production of more complex geometries. Furthermore, the defined adjustment of part properties like strength, grain size/orientation and surface conditions can be achieved through the appropriate process parameter settings and consequently by setting a specific temperature profile in combination with the degree of deformation. The results presented from tube forming start with an investigation into the resulting twist phenomena in flange processing. In this way, the influence of the main parameters, such as rotation speed, feed rate, forming paths and tool friction surface, and their effects on temperature, forces and finally the twist behavior are analyzed. Following this, the significant correlations with the parameters and a new process strategy are set out in order to visualize the possibility of achieving a defined grain texture orientation.

  20. Shapes and alignments at high spin in some rare-earth nuclei

    International Nuclear Information System (INIS)

    Deleplanque, M.A.; Diamond, R.M.; Stephens, F.S.; Macchiavelli, A.O.; Doessing, T.; Draper, J.E.; Dines, E.L.

    1985-01-01

    The structure of nuclei at high spins is dominated by an interplay between deformation and alignment effects. Cranking models predict various shapes but at the highest spins, there is a tendency towards large triaxial deformations and sometimes towards very large prolate deformations (superdeformations). Directly involved in the shape changes are aligned orbitals which come down to the Fermi level as the nucleus rotates more rapidly. At a certain frequency, they become populated and cause large alignments. The mechanism of these changes has been explored by looking at a series of rare earth quasirotational nuclei from Dy to W in the transition region around N = 90 neutrons. The continuum spectra, corrected for incomplete population (feeding) of the high spins, are directly proportional to dynamic effective moments of inertia which describe how much spin is generated at each rotational frequency

  1. Magnetization transfer and spin lock MR imaging of patellar cartilage degeneration at 0.1 T

    International Nuclear Information System (INIS)

    Koskinen, S.K.; Ylae-Outinen, H.; Komu, M.E.S.; Aho, H.J.

    1997-01-01

    Purpose: To investigate magnetization transfer (MT) parameters and rotating frame relaxation time T1ρ in patellar cartilage at different levels of degeneration. Material and Methods: Thirty cadaveric patellae were examined at 0.1 T using the time-dependent saturation-transfer MT technique and the spin lock (SL) technique. In an SL experiment, nuclear spins are locked with a radiofrequency (RF) field, and the locked nuclear magnetization relaxes along the magnetic component of the locking RF field. The specimens were divided into three groups according to the level of cartilage degeneration. MT parameters and T1ρ were measured. Results: The MT effect was greater in degenerated cartilage than in normal cartilage. T1ρ was longer in advanced cartilage degeneration than in intermediate cartilage degeneration. Conculsion: The results suggest that more studies are needed to fully establish the value of SL imaging in cartilage degeneration. (orig.)

  2. Depolarization of neutron spin echo by magnetic fluid

    International Nuclear Information System (INIS)

    Achiwa, N.; Sirozu, G.; Nishioka, T.; Ebisawa, T.; Hino, M.; Tasaki, S.; Kawai, T.; Yamazaki, D.

    2001-01-01

    A new method to study the fluctuations of magnetization in magnetic fluids by measuring relations between the phase shift of Larmor precession and the visibility of the neutron spin echo caused by the change of flight path length is studied. Magnetic fluid in which fine particles of magnetite of about 10 nm diameters coated with oleic acid and suspended in water was used. Thickness of the sample was 2 mm. In the dynamics of magnetic fluids, Brownian motions of colloids and the thermal fluctuations of magnetization known as the superparamagnetism are dominant. Isolated ferromagnetic particles of the present size are superparamagnetic but they aggregate to form clusters in a weak magnetic field in the sample of 40% weight density. When neutrons pass the sample, spins process in the magnetic flux density of the clusters fluctuating in time and space. Consequently the Larmor precession phases become distributed and the quantization axes are fluctuated. The result is observed as a decrease of the visibility of the spin echo signals. The change of magnetic flux density in the magnetic fluid is measured from the change of echo visibility of the neutrons, vice versa. In the present experiment, echo was measured at q=0. It is observed that the phase shift changes as a quadratic function of the sample angle reflecting the change of the path length through the sample. Since the number of Larmor precession is proportional to the product of the magnetic field and the length of the flight path, mean flux density in the magnetic fluid is calculated from the phase shift. On the other hand, the decrease of the spin echo amplitude as the function of the sample angle reflects the time and space fluctuations of the flux density in the sample. If the direction of the magnetic flux density vector (quantization axis) changes slowly enough compared to the Larmor precession period while a neutron passes one magnetic domain, the neutron spin rotation in the domain is given by the spin

  3. Spin doctoring

    OpenAIRE

    Vozková, Markéta

    2011-01-01

    1 ABSTRACT The aim of this text is to provide an analysis of the phenomenon of spin doctoring in the Euro-Atlantic area. Spin doctors are educated people in the fields of semiotics, cultural studies, public relations, political communication and especially familiar with the infrastructure and the functioning of the media industry. Critical reflection of manipulative communication techniques puts spin phenomenon in historical perspective and traces its practical use in today's social communica...

  4. A planning and delivery study of a rotational IMRT technique with burst delivery

    International Nuclear Information System (INIS)

    Kainz, Kristofer; Chen, Guang-Pei; Chang, Yu-Wen; Prah, Douglas; Sharon Qi, X.; Shukla, Himanshu P.; Stahl, Johannes; Allen Li, X.

    2011-01-01

    Purpose: A novel rotational IMRT (rIMRT) technique using burst delivery (continuous gantry rotation with beam off during MLC repositioning) is investigated. The authors evaluate the plan quality and delivery efficiency and accuracy of this dynamic technique with a conventional flat 6 MV photon beam. Methods: Burst-delivery rIMRT was implemented in a planning system and delivered with a 160-MLC linac. Ten rIMRT plans were generated for five anonymized patient cases encompassing head and neck, brain, prostate, and prone breast. All plans were analyzed retrospectively and not used for treatment. Among the varied plan parameters were the number of optimization points, number of arcs, gantry speed, and gantry angle range (alpha) over which the beam is turned on at each optimization point. Combined rotational/step-and-shoot rIMRT plans were also created by superimposing multiple-segment static fields at several optimization points. The rIMRT trial plans were compared with each other and with plans generated using helical tomotherapy and VMAT. Burst-mode rotational IMRT plans were delivered and verified using a diode array, ionization chambers, thermoluminescent dosimeters, and film. Results: Burst-mode rIMRT can achieve plan quality comparable to helical tomotherapy, while the former may lead to slightly better OAR sparing for certain cases and the latter generally achieves slightly lower hot spots. Few instances were found in which increasing the number of optimization points above 36, or superimposing step-and-shoot IMRT segments, led to statistically significant improvements in OAR sparing. Using an additional rIMRT partial arc yielded substantial OAR dose improvements for the brain case. Measured doses from the rIMRT plan delivery were within 4% of the plan calculation in low dose gradient regions. Delivery time range was 228-375 s for single-arc rIMRT 200-cGy prescription with a 300 MU/min dose rate, comparable to tomotherapy and VMAT. Conclusions: Rotational IMRT

  5. Flow past a rotating cylinder

    Science.gov (United States)

    Mittal, Sanjay; Kumar, Bhaskar

    2003-02-01

    Flow past a spinning circular cylinder placed in a uniform stream is investigated via two-dimensional computations. A stabilized finite element method is utilized to solve the incompressible Navier Stokes equations in the primitive variables formulation. The Reynolds number based on the cylinder diameter and free-stream speed of the flow is 200. The non-dimensional rotation rate, [alpha] (ratio of the surface speed and freestream speed), is varied between 0 and 5. The time integration of the flow equations is carried out for very large dimensionless time. Vortex shedding is observed for [alpha] cylinder. The results from the stability analysis for the rotating cylinder are in very good agreement with those from direct numerical simulations. For large rotation rates, very large lift coefficients can be obtained via the Magnus effect. However, the power requirement for rotating the cylinder increases rapidly with rotation rate.

  6. Part II: Biomechanical assessment for a footprint-restoring transosseous-equivalent rotator cuff repair technique compared with a double-row repair technique.

    Science.gov (United States)

    Park, Maxwell C; Tibone, James E; ElAttrache, Neal S; Ahmad, Christopher S; Jun, Bong-Jae; Lee, Thay Q

    2007-01-01

    We hypothesized that a transosseous-equivalent repair would demonstrate improved tensile strength and gap formation between the tendon and tuberosity when compared with a double-row technique. In 6 fresh-frozen human shoulders, a transosseous-equivalent rotator cuff repair was performed: a suture limb from each of two medial anchors was bridged over the tendon and fixed laterally with an interference screw. In 6 contralateral matched-pair specimens, a double-row repair was performed. For all repairs, a materials testing machine was used to load each repair cyclically from 10 N to 180 N for 30 cycles; each repair underwent tensile testing to measure failure loads at a deformation rate of 1 mm/sec. Gap formation between the tendon edge and insertion was measured with a video digitizing system. The mean ultimate load to failure was significantly greater for the transosseous-equivalent technique (443.0 +/- 87.8 N) compared with the double-row technique (299.2 +/- 52.5 N) (P = .043). Gap formation during cyclic loading was not significantly different between the transosseous-equivalent and double-row techniques, with mean values of 3.74 +/- 1.51 mm and 3.79 +/- 0.68 mm, respectively (P = .95). Stiffness for all cycles was not statistically different between the two constructs (P > .40). The transosseous-equivalent rotator cuff repair technique improves ultimate failure loads when compared with a double-row technique. Gap formation is similar for both techniques. A transosseous-equivalent repair helps restore footprint dimensions and provides a stronger repair than the double-row technique, which may help optimize healing biology.

  7. On Physical Interpretation of the In-Site Measurement of Earth Rotation by Ring Laser Gyrometers

    Science.gov (United States)

    Chao, B. F.

    2004-01-01

    Large ring laser gyrometers under development have demonstrated the capability of detecting minute ground motions and deformations on a wide range of timescales. The next challenge and goal is to measure the Earth's rotation variations to a precision that rivals that of the present space-geodesy techniques, thus providing an in-situ (and cost effective alternatives of Earth rotation measurement for geophysical research and geodetic applications. Aside from thermal and mechanical instabilities, "undesirable" ground motion and tilt that appear in the signal will need to be removed before any variation in Earth rotation can be detected. Removal of these signals, some of them are larger than the sought rotation signals, has been a typical procedure in many precise geophysical instruments, such as gravimeters, seismometers, and tiltmeters. The remaining Earth rotation signal resides in both the spin around the axis and in the orientation of the axis. In the case of the latter, the in-situ measurement is complementary to the space-geodetic observables in terms of polar motion and nutation, a fact to be exploited.

  8. The Wibbly-Wobbly Moon: Rotational Dynamics of the Moon After Large Impacts

    Science.gov (United States)

    Keane, J. T.; Johnson, B. C.; Matsuyama, I.; Siegler, M.

    2017-12-01

    The spins of planets are not constant with time; they continuously evolve in response to both external and internal forces. One of the most dramatic ways a planet's spin can change is via impacts. Impacts change the planet's angular momentum, energy, and moments of inertia. These changes can have important consequences for the geology of the planet. For the well-studied case of the Moon, these repercussions include everything from changing the orientation of the magnetic field, controlling the geometry of fault networks, and altering the stability of volatiles (e.g. water ice) in permanently shadowed regions. While previous studies have investigated the dynamical effects of impacts on the Moon, most use simplistic models for the impact basin formation process—often only considering the impulsive change in the Moon's angular momentum, and occasionally the change in the Moon's moments of inertia from a simplified basin geometry (e.g. a cylindrical hole surrounded by a cylindrical ejecta blanket). These simplifications obscure some of the subtler and more complicated dynamics that occur in the aftermath of an impact. In this work, we present new model results for the rotational dynamics of the Moon after large, basin-forming impacts. We couple iSALE hydrocode simulations with the analytical and numerical formalisms of rotational dynamics. These simulations allow us to quantitatively track how different impact processes alter the Moon's moments of inertia, including basin formation, mantle uplift, impact heating, and ejecta-blanket emplacement. This unique combination of techniques enables us to more accurately track the spin of the Moon in the aftermath of these impacts, including periods of non-synchronous and non-principal-axis rotation, libration, and long-term reorientation (true polar wander). We find that the perturbation of the Moon's moments of inertia immediately after impact is several times larger than what is expected based on the present-day gravity

  9. 'Static' octupole deformation at high spin

    International Nuclear Information System (INIS)

    Nazarewicz, W.

    1985-01-01

    Rotational bands characterized by spin states of alternating parity p=(-1) I connected by enhanced E1 transitions have recently been observed in several nuclei from the Ra-Th region. They can be interpreted by means of a reflection asymmetric mean field theory. The interplay between octupole deformation and rotation is briefly discussed. For nuclei with ground state octupole deformation a transition to a reflection symmetric shape is expected around I=22. (orig.)

  10. All-optical evaluation of spin-orbit interaction based on diffusive spin motion in a two-dimensional electron gas

    Energy Technology Data Exchange (ETDEWEB)

    Kohda, M. [IBM Research–Zürich, Säumerstrasse 4, CH-8803 Rüschlikon (Switzerland); Department of Materials Science, Tohoku University, 980-8579 Sendai (Japan); Altmann, P.; Salis, G. [IBM Research–Zürich, Säumerstrasse 4, CH-8803 Rüschlikon (Switzerland); Schuh, D.; Ganichev, S. D. [Institute of Experimental and Applied Physics, University of Regensburg, D-93040 Regensburg (Germany); Wegscheider, W. [Solid State Physics Laboratory, ETH Zürich, CH-8093 Zürich (Switzerland)

    2015-10-26

    A method is presented that enables the measurement of spin-orbit coefficients in a diffusive two-dimensional electron gas without the need for processing the sample structure, applying electrical currents or resolving the spatial pattern of the spin mode. It is based on the dependence of the average electron velocity on the spatial distance between local excitation and detection of spin polarization, resulting in a variation of spin precession frequency that in an external magnetic field is linear in the spatial separation. By scanning the relative positions of the exciting and probing spots in a time-resolved Kerr rotation microscope, frequency gradients along the [100] and [010] crystal axes of GaAs/AlGaAs QWs are measured to obtain the Rashba and Dresselhaus spin-orbit coefficients, α and β. This simple method can be applied in a variety of materials with electron diffusion for evaluating spin-orbit coefficients.

  11. Spinning rate decay of levitated high-Tc superconductors in rotational magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Terentiev, A.N.; Kutukova, E.O.; Kuznetsov, A.A. (Inst. of Chemical Physics, Academy of Sciences, Moscow (Russia)); Mozhaev, A.P. (Moscow State Univ., Dept. of Chemistry (Russia))

    1992-04-01

    The rotation damping of a levitated superconductor was examined in the static field of a ring-shaped magnet and in the rotating field of coils. It was demonstrated that the pinning force mainly contributed to magnetic friction while the influence of a viscous component was negligible. The rotating magnetic field created a torque, reducing the angular deceleration under relaxation. Dependence of the rotational field-induced torque on the field-intensity was step-like. A relationship between the step-like behavior of rotational field-induced torque and pinning center distribution is discussed. The origins of friction torque and rotational field-produced torque are discussed. (orig.).

  12. Boson-mediated quantum spin simulators in transverse fields: X Y model and spin-boson entanglement

    Science.gov (United States)

    Wall, Michael L.; Safavi-Naini, Arghavan; Rey, Ana Maria

    2017-01-01

    The coupling of spins to long-wavelength bosonic modes is a prominent means to engineer long-range spin-spin interactions, and has been realized in a variety of platforms, such as atoms in optical cavities and trapped ions. To date, much of the experimental focus has been on the realization of long-range Ising models, but generalizations to other spin models are highly desirable. In this work, we explore a previously unappreciated connection between the realization of an X Y model by off-resonant driving of a single sideband of boson excitation (i.e., a single-beam Mølmer-Sørensen scheme) and a boson-mediated Ising simulator in the presence of a transverse field. In particular, we show that these two schemes have the same effective Hamiltonian in suitably defined rotating frames, and analyze the emergent effective X Y spin model through a truncated Magnus series and numerical simulations. In addition to X Y spin-spin interactions that can be nonperturbatively renormalized from the naive Ising spin-spin coupling constants, we find an effective transverse field that is dependent on the thermal energy of the bosons, as well as other spin-boson couplings that cause spin-boson entanglement not to vanish at any time. In the case of a boson-mediated Ising simulator with transverse field, we discuss the crossover from transverse field Ising-like to X Y -like spin behavior as a function of field strength.

  13. Asteroseismology of Red-Giant Stars: Mixed Modes, Differential Rotation, and Eccentric Binaries

    Science.gov (United States)

    Beck, Paul G.

    2013-12-01

    Astronomers are aware of rotation in stars since Galileo Galilei attributed the movement of sunspots to rotation of the Sun in 1613. In contrast to the Sun, whose surface can be resolved by small telescopes or even the (protected) eye, we detect stars as point sources with no spatial information. Numerous techniques have been developed to derive information about stellar rotation. Unfortunately, most observational data allow only for the surface rotational rate to be inferred. The internal rotational profile, which has a great effect on the stellar structure and evolution, remains hidden below the top layers of the star - the essential is hidden to the eyes. Asteroseismology allows us to "sense" indirectly deep below the stellar surface. Oscillations that propagate through the star provide information about the deep stellar interiors while they also distort the stellar surface in characteristic patterns leading to detectable brightness or velocity variations. Also, certain oscillation modes are sensitive to internal rotation and carry information on how the star is spinning deep inside. Thanks to the unprecedented quality of NASA's space telescope Kepler, numerous detailed observations of stars in various evolutionary stages are available. Such high quality data allow that for many stars, rotation can not only be constrained from surface rotation, but also investigated through seismic studies. The work presented in this thesis focuses on the oscillations and internal rotational gradient of evolved single and binary stars. It is shown that the seismic analysis can reach the cores of oscillating red-giant stars and that these cores are rapidly rotating, while nested in a slowly rotating convective envelope.

  14. Attempt to explain black hole spin in X-ray binaries by new physics

    International Nuclear Information System (INIS)

    Bambi, Cosimo

    2015-01-01

    It is widely believed that the spin of black holes in X-ray binaries is mainly natal. A significant spin-up from accretion is not possible. If the secondary has a low mass, the black hole spin cannot change too much even if the black hole swallows the whole stellar companion. If the secondary has a high mass, its lifetime is too short to transfer the necessary amount of matter and spin the black hole up. However, while black holes formed from the collapse of a massive star with solarmetallicity are expected to have low birth spin, current spin measurements show that some black holes in X-ray binaries are rotating very rapidly. Here we show that, if these objects are not the Kerr black holes of general relativity, the accretion of a small amount of matter (∝2 M s un) can make them look like very fast-rotating Kerr black holes. Such a possibility is not in contradiction with any observation and it can explain current spin measurements in a very simple way. (orig.)

  15. Computational efficiency improvement with Wigner rotation technique in studying atoms in intense few-cycle circularly polarized pulses

    International Nuclear Information System (INIS)

    Yuan, Minghu; Feng, Liqiang; Lü, Rui; Chu, Tianshu

    2014-01-01

    We show that by introducing Wigner rotation technique into the solution of time-dependent Schrödinger equation in length gauge, computational efficiency can be greatly improved in describing atoms in intense few-cycle circularly polarized laser pulses. The methodology with Wigner rotation technique underlying our openMP parallel computational code for circularly polarized laser pulses is described. Results of test calculations to investigate the scaling property of the computational code with the number of the electronic angular basis function l as well as the strong field phenomena are presented and discussed for the hydrogen atom

  16. In-beam study of the rotational states in actinides after alpha-induced nuclear reactions

    International Nuclear Information System (INIS)

    Hardt, K.

    1983-01-01

    In the experiments described in this thesis the ground state rotational bands of a whole series of actinide isotopes has been studied by means of α-induced nuclear reactions. The rotational bands studied in the even isotopes could be identified up to a spin of about 16 (h/2π). With this data it was now possible to establish a broad systematic of the rotational energies up to relatively high angular momenta. Also in the odd isotopes 233 U and 239 Pu it was possible to follow the ground state rotational bands up to higher spins and to compare them with predictions of the rotational model. By means of the (α,α'2n) reaction the nuclei 230 Th and especially 228 Th could by populated. (orig./HSI) [de

  17. Deformation and shape transitions in hot rotating neutron deficient Te isotopes

    International Nuclear Information System (INIS)

    Aggarwal, Mamta; Mazumdar, I.

    2009-01-01

    Evolution of the nuclear shapes and deformations under the influence of temperature and rotation is investigated in Te isotopes with neutron number ranging from the proton drip line to the stability valley. Spin dependent critical temperatures for the shape transitions in Te nuclei are computed. Shape transitions from prolate at low temperature and spin to oblate via triaxiality are seen with increasing neutron number and spin.

  18. Hole dynamics and spin currents after ionization in strong circularly polarized laser fields

    International Nuclear Information System (INIS)

    Barth, Ingo; Smirnova, Olga

    2014-01-01

    We apply the time-dependent analytical R-matrix theory to develop a movie of hole motion in a Kr atom upon ionization by strong circularly polarized field. We find rich hole dynamics, ranging from rotation to swinging motion. The motion of the hole depends on the final energy and the spin of the photoelectron and can be controlled by the laser frequency and intensity. Crucially, hole rotation is a purely non-adiabatic effect, completely missing in the framework of quasistatic (adiabatic) tunneling theories. We explore the possibility to use hole rotation as a clock for measuring ionization time. Analyzing the relationship between the relative phases in different ionization channels we show that in the case of short-range electron-core interaction the hole is always initially aligned along the instantaneous direction of the laser field, signifying zero delays in ionization. Finally, we show that strong-field ionization in circular fields creates spin currents (i.e. different flow of spin-up and spin-down density in space) in the ions. This phenomenon is intimately related to the production of spin-polarized electrons in strong laser fields Barth and Smirnova (2013 Phys. Rev. A 88 013401). We demonstrate that rich spin dynamics of electrons and holes produced during strong field ionization can occur in typical experimental conditions and does not require relativistic intensities or strong magnetic fields. (paper)

  19. Electron charge and spin delocalization revealed in the optically probed longitudinal and transverse spin dynamics in n -GaAs

    Science.gov (United States)

    Belykh, V. V.; Kavokin, K. V.; Yakovlev, D. R.; Bayer, M.

    2017-12-01

    The evolution of the electron spin dynamics as consequence of carrier delocalization in n -type GaAs is investigated by the recently developed extended pump-probe Kerr/Faraday rotation spectroscopy. We find that isolated electrons localized on donors demonstrate a prominent difference between the longitudinal and transverse spin relaxation rates in a magnetic field, which is almost absent in the metallic phase. The inhomogeneous transverse dephasing time T2* of the spin ensemble strongly increases upon electron delocalization as a result of motional narrowing that can be induced by increasing either the donor concentration or the temperature. An unexpected relation between T2* and the longitudinal spin relaxation time T1 is found, namely, that their product is about constant, as explained by the magnetic field effect on the spin diffusion. We observe a two-stage longitudinal spin relaxation, which suggests the establishment of spin temperature in the system of exchange-coupled donor-bound electrons.

  20. Spinning charged test particles and Cosmic Censorship

    Energy Technology Data Exchange (ETDEWEB)

    Caderni, N [Cambridge Univ. Inst. of Astronomy (UK); Calvani, M [Padua Univ. (Italy). Ist. di Astronomia

    1979-04-16

    The authors consider spinning charged test particles in the gravitational field of a rotating charged black hole, and it is shown that the hole cannot be destroyed, according to the Cosmic Censorship hypothesis.

  1. LARGE SUPER-FAST ROTATOR HUNTING USING THE INTERMEDIATE PALOMAR TRANSIENT FACTORY

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Chan-Kao; Lin, Hsing-Wen; Ip, Wing-Huen [Institute of Astronomy, National Central University, Jhongli, Taiwan (China); Prince, Thomas A.; Kulkarni, Shrinivas R.; Levitan, David [Division of Physics, Mathematics and Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States); Laher, Russ; Surace, Jason, E-mail: rex@astro.ncu.edu.tw [Spitzer Science Center, California Institute of Technology, M/S 314-6, Pasadena, CA 91125 (United States)

    2016-12-01

    In order to look for large super-fast rotators, in late 2014 and early 2015, five dedicated surveys covering ∼188 deg{sup 2} in the ecliptic plane have been carried out in the R -band, with ∼10 minute cadence using the intermediate Palomar Transient Factory. Among 1029 reliable rotation periods obtained from the surveys, we discovered 1 new large super-fast rotator, (40511) 1999 RE88, and 18 other candidates. (40511) 1999 RE88 is an S-type inner main-belt asteroid with a diameter of D  = 1.9 ± 0.3 km, a rotation period of P  = 1.96 ± 0.01 hr, and a light curve amplitude of Δ m  ∼ 1.0 mag. To maintain such fast rotation, an internal cohesive strength of ∼780 Pa is required. Combining all known large super-fast rotators, their cohesive strengths all fall in the range of 100–1000 Pa of lunar regolith. However, the number of large super-fast rotators seems to be far less than the whole asteroid population. This might indicate a peculiar asteroid group for them. Although the detection efficiency for a long rotation period is greatly reduced due to our two-day observation time span, the spin-rate distributions of this work show consistent results with Chang et al. (2015), after considering the possible observational bias in our surveys. It shows a number decrease with an increase of spin rate for asteroids with a diameter of 3 ⩽  D  ⩽ 15 km, and a number drop at a spin rate of f  = 5 rev day{sup −1} for asteroids with D  ⩽ 3 km.

  2. Modified suture-bridge technique to prevent a marginal dog-ear deformity improves structural integrity after rotator cuff repair.

    Science.gov (United States)

    Ryu, Keun Jung; Kim, Bang Hyun; Lee, Yohan; Lee, Yoon Seok; Kim, Jae Hwa

    2015-03-01

    The arthroscopic suture-bridge technique has proved to provide biomechanically firm fixation of the torn rotator cuff to the tuberosity by increasing the footprint contact area and pressure. However, a marginal dog-ear deformity is encountered not infrequently when this technique is used, impeding full restoration of the torn cuff. To evaluate the structural and functional outcomes of the use of a modified suture-bridge technique to prevent a marginal dog-ear deformity compared with a conventional suture-bridge method in rotator cuff repair. Cohort study; Level of evidence 2. A consecutive series of 71 patients aged 50 to 65 years who underwent arthroscopic rotator cuff repair for full-thickness medium-sized to massive tears was evaluated. Patients were divided into 2 groups according to repair technique: a conventional suture-bridge technique (34 patients; group A) versus a modified suture-bridge technique to prevent a marginal dog-ear deformity (37 patients; group B). Radiographic evaluations included postoperative cuff integrity using MRI. Functional evaluations included pre- and postoperative range of motion (ROM), pain visual analog scale (VAS), the University of California, Los Angeles (UCLA) shoulder rating scale, the Constant score, and the American Shoulder and Elbow Surgeons (ASES) score. All patients were followed up clinically at a minimum of 1 year. When the 2 surgical techniques were compared, postoperative structural integrity by Sugaya classification showed the distribution of types I:II:III:IV:V to be 4:20:2:4:4 in group A and 20:12:4:0:1 in group B. More subjects in group B had a favorable Sugaya type compared with group A (P bridge technique repairs were found in the retear group (P = .03). There were significant differences between healed and retear groups in functional outcome scores, with worse results in the retear group. A modified suture-bridge technique to prevent a marginal dog-ear deformity provided better structural outcomes than a

  3. The pure rotational spectrum of the CrS radical in its X  5Π(r) state.

    Science.gov (United States)

    Pulliam, R L; Ziurys, L M

    2010-11-07

    The pure rotational spectrum of the CrS radical has been measured in its ground X (5)Π(r) state using gas-phase millimeter/submillimeter direct absorption methods. The molecule was created by the reaction of chromium vapor, sublimed in a Broida-type oven, with hydrogen sulfide. Eleven rotational transitions were recorded for this free radical in the frequency range of 280-405 GHz; in most transitions, all five spin components were observed, and lambda-doubling was resolved in the Ω=0, 1, and 2 ladders. The data were fit with a Hund's case (a) Hamiltonian and rotational, spin-orbit, spin-spin, and lambda-doubling constants were established. Higher order spin and spin-orbit terms were essential in the analysis. The lambda-doubling constants indicate a nearby (5)Σ(+) state at an energy of ∼1500-2000 cm(-1). A bond length of 2.0781 Å was derived for CrS from the data, which is larger than the value of 2.0682 Å found for MnS by ∼0.01 Å. In contrast, the bond distance for MnO is greater than that of CrO by 0.03 Å, an illustration of the subtle differences between 3d oxide and sulfides. CrS is the second molecule in a (5)Π state that has been studied by rotational spectroscopy.

  4. Effect of surface tension on the dynamical behavior of bubble in rotating fluids under low gravity environment

    Science.gov (United States)

    Hung, R. J.; Tsao, Y. D.; Leslie, Fred W.; Hong, B. B.

    1988-01-01

    Time dependent evolutions of the profile of free surface (bubble shapes) for a cylindrical container partially filled with a Newtonian fluid of constant density, rotating about its axis of symmetry, have been studied. Numerical computations of the dynamics of bubble shapes have been carried out with the following situations: (1) linear functions of spin-up and spin-down in low and microgravity environments, (2) linear functions of increasing and decreasing gravity enviroment in high and low rotating cylidner speeds, (3) step functions of spin-up and spin-down in a low gravity environment, and (4) sinusoidal function oscillation of gravity environment in high and low rotating cylinder speeds. The initial condition of bubble profiles was adopted from the steady-state formulations in which the computer algorithms have been developed by Hung and Leslie (1988), and Hung et al. (1988).

  5. Effect of high-frequency excitation on natural frequencies of spinning discs

    DEFF Research Database (Denmark)

    Hansen, Morten Hartvig

    2000-01-01

    The effect of high-frequency, non-resonant parametric excitation on the low-frequency response of spinning discs is considered. The parametric excitation is obtained through a non-constant rotation speed, where the frequency of the pulsating overlay is much higher than the lowest natural frequenc......The effect of high-frequency, non-resonant parametric excitation on the low-frequency response of spinning discs is considered. The parametric excitation is obtained through a non-constant rotation speed, where the frequency of the pulsating overlay is much higher than the lowest natural...

  6. Vertical-to-Horizontal Rotational Myocutaneous Flap for Repairing Cicatricial Lower Lid Ectropion: A Novel Surgical Technique

    Directory of Open Access Journals (Sweden)

    Yu-Fan Chang

    2017-01-01

    Full Text Available Objective. To evaluate the efficacy and complications of a novel surgical technique for cicatricial lower lid ectropion that uses a vertical-to-horizontal (V-to-H rotational myocutaneous flap procedure (Tsai procedure. Methods. We performed the V-to-H rotational myocutaneous flap procedure on 20 eyelids in 20 patients with mild to moderate cicatricial lower lid ectropion. A vertical myocutaneous flap was created from the anterior lamella of the vertical pedicle in the lateral third of the lower eyelid. Following a horizontal relaxing incision from the base of the flap, a vertical myocutaneous flap was created and rotated to horizontal. Two patients with combined cicatricial ectropion and paralytic lagophthalmos simultaneously underwent additional lateral tarsorrhaphy. Results. After a minimum follow-up period of 6 months, all patients showed good anatomical and functional improvement with decreased dependence on topical lubricants and a satisfactory cosmetic appearance. Two patients with combined cicatricial and paralytic ectropion had mild residual asymptomatic lagophthalmos. No patients required further revision surgery and there were no complications or recurrence. Conclusion. The V-to-H rotational myocutaneous flap technique was an effective and simple one-stage procedure for correcting cicatricial lower lid ectropion. It lengthened the anterior lamella and tightened horizontal eyelid laxity without the need for a free skin graft.

  7. Neutron spin precession in samples of polarised nuclei and neutron spin phase imaging

    Energy Technology Data Exchange (ETDEWEB)

    Piegsa, Florian Michael

    2009-07-09

    The doublet neutron-deuteron (nd) scattering length b{sub 2,d}, which is at present only known with an accuracy of 5%, is particularly well suited to fix three-body forces in novel effective field theories at low energies. The understanding of such few-nucleon systems is essential, e.g. for predictions of element abundances in the big-bang and stellar fusion. b{sub 2,d} can be obtained via a linear combination of the spin-independent nd scattering length b{sub c,d} and the spin-dependent one, b{sub i,d}. The aim of this thesis was to perform a high-accuracy measurement of the latter to improve the relative accuracy of b{sub 2,d} below 1%. The experiment was performed at the fundamental neutron physics beam line FUNSPIN at the Paul Scherrer Institute in Switzerland. It utilises the effect that the spin of a neutron passing through a target with polarised nuclei performs a pseudomagnetic precession proportional to the spin-dependent scattering length of the nuclei. An ideal method to measure this precession angle very accurately is Ramsey's atomic beam technique, adapted to neutrons. The most crucial part of the experimental setup is the so-called frozen spin target, which consists of a specially designed dilution refrigerator and contains a sample with dynamically polarised nuclear spins. The polarisation of the sample is determined by nuclear magnetic resonance (NMR) techniques. It turned out that the relaxation of the nuclear spins during the necessary ''cross-calibration'' of the two employed NMR systems is ultimately limiting the achievable accuracy of b{sub i,d}. During the extensive use of the Ramsey resonance method in the neutron-deuteron experiment, an idea emerged that the applied technique could be exploited in a completely different context, namely polarised neutron radiography. Hence, the second part of the thesis covers the development of a novel neutron radiography technique, based on the spin-dependent interaction of the

  8. Neutron spin precession in samples of polarised nuclei and neutron spin phase imaging

    International Nuclear Information System (INIS)

    Piegsa, Florian Michael

    2009-01-01

    The doublet neutron-deuteron (nd) scattering length b 2,d , which is at present only known with an accuracy of 5%, is particularly well suited to fix three-body forces in novel effective field theories at low energies. The understanding of such few-nucleon systems is essential, e.g. for predictions of element abundances in the big-bang and stellar fusion. b 2,d can be obtained via a linear combination of the spin-independent nd scattering length b c,d and the spin-dependent one, b i,d . The aim of this thesis was to perform a high-accuracy measurement of the latter to improve the relative accuracy of b 2,d below 1%. The experiment was performed at the fundamental neutron physics beam line FUNSPIN at the Paul Scherrer Institute in Switzerland. It utilises the effect that the spin of a neutron passing through a target with polarised nuclei performs a pseudomagnetic precession proportional to the spin-dependent scattering length of the nuclei. An ideal method to measure this precession angle very accurately is Ramsey's atomic beam technique, adapted to neutrons. The most crucial part of the experimental setup is the so-called frozen spin target, which consists of a specially designed dilution refrigerator and contains a sample with dynamically polarised nuclear spins. The polarisation of the sample is determined by nuclear magnetic resonance (NMR) techniques. It turned out that the relaxation of the nuclear spins during the necessary ''cross-calibration'' of the two employed NMR systems is ultimately limiting the achievable accuracy of b i,d . During the extensive use of the Ramsey resonance method in the neutron-deuteron experiment, an idea emerged that the applied technique could be exploited in a completely different context, namely polarised neutron radiography. Hence, the second part of the thesis covers the development of a novel neutron radiography technique, based on the spin-dependent interaction of the neutron with ferromagnetic samples and magnetic fields

  9. Microscopic studies of nonlocal spin dynamics and spin transport (invited)

    Energy Technology Data Exchange (ETDEWEB)

    Adur, Rohan; Du, Chunhui; Cardellino, Jeremy; Scozzaro, Nicolas; Wolfe, Christopher S.; Wang, Hailong; Herman, Michael; Bhallamudi, Vidya P.; Pelekhov, Denis V.; Yang, Fengyuan; Hammel, P. Chris, E-mail: hammel@physics.osu.edu [Department of Physics, The Ohio State University, Columbus, Ohio 43210 (United States)

    2015-05-07

    Understanding the behavior of spins coupling across interfaces in the study of spin current generation and transport is a fundamental challenge that is important for spintronics applications. The transfer of spin angular momentum from a ferromagnet into an adjacent normal material as a consequence of the precession of the magnetization of the ferromagnet is a process known as spin pumping. We find that, in certain circumstances, the insertion of an intervening normal metal can enhance spin pumping between an excited ferromagnetic magnetization and a normal metal layer as a consequence of improved spin conductance matching. We have studied this using inverse spin Hall effect and enhanced damping measurements. Scanned probe magnetic resonance techniques are a complementary tool in this context offering high resolution magnetic resonance imaging, localized spin excitation, and direct measurement of spin lifetimes or damping. Localized magnetic resonance studies of size-dependent spin dynamics in the absence of lithographic confinement in both ferromagnets and paramagnets reveal the close relationship between spin transport and spin lifetime at microscopic length scales. Finally, detection of ferromagnetic resonance of a ferromagnetic film using the photoluminescence of nitrogen vacancy spins in neighboring nanodiamonds demonstrates long-range spin transport between insulating materials, indicating the complexity and generality of spin transport in diverse, spatially separated, material systems.

  10. Microscopic studies of nonlocal spin dynamics and spin transport (invited)

    Science.gov (United States)

    Adur, Rohan; Du, Chunhui; Cardellino, Jeremy; Scozzaro, Nicolas; Wolfe, Christopher S.; Wang, Hailong; Herman, Michael; Bhallamudi, Vidya P.; Pelekhov, Denis V.; Yang, Fengyuan; Hammel, P. Chris

    2015-05-01

    Understanding the behavior of spins coupling across interfaces in the study of spin current generation and transport is a fundamental challenge that is important for spintronics applications. The transfer of spin angular momentum from a ferromagnet into an adjacent normal material as a consequence of the precession of the magnetization of the ferromagnet is a process known as spin pumping. We find that, in certain circumstances, the insertion of an intervening normal metal can enhance spin pumping between an excited ferromagnetic magnetization and a normal metal layer as a consequence of improved spin conductance matching. We have studied this using inverse spin Hall effect and enhanced damping measurements. Scanned probe magnetic resonance techniques are a complementary tool in this context offering high resolution magnetic resonance imaging, localized spin excitation, and direct measurement of spin lifetimes or damping. Localized magnetic resonance studies of size-dependent spin dynamics in the absence of lithographic confinement in both ferromagnets and paramagnets reveal the close relationship between spin transport and spin lifetime at microscopic length scales. Finally, detection of ferromagnetic resonance of a ferromagnetic film using the photoluminescence of nitrogen vacancy spins in neighboring nanodiamonds demonstrates long-range spin transport between insulating materials, indicating the complexity and generality of spin transport in diverse, spatially separated, material systems.

  11. Microscopic studies of nonlocal spin dynamics and spin transport (invited)

    International Nuclear Information System (INIS)

    Adur, Rohan; Du, Chunhui; Cardellino, Jeremy; Scozzaro, Nicolas; Wolfe, Christopher S.; Wang, Hailong; Herman, Michael; Bhallamudi, Vidya P.; Pelekhov, Denis V.; Yang, Fengyuan; Hammel, P. Chris

    2015-01-01

    Understanding the behavior of spins coupling across interfaces in the study of spin current generation and transport is a fundamental challenge that is important for spintronics applications. The transfer of spin angular momentum from a ferromagnet into an adjacent normal material as a consequence of the precession of the magnetization of the ferromagnet is a process known as spin pumping. We find that, in certain circumstances, the insertion of an intervening normal metal can enhance spin pumping between an excited ferromagnetic magnetization and a normal metal layer as a consequence of improved spin conductance matching. We have studied this using inverse spin Hall effect and enhanced damping measurements. Scanned probe magnetic resonance techniques are a complementary tool in this context offering high resolution magnetic resonance imaging, localized spin excitation, and direct measurement of spin lifetimes or damping. Localized magnetic resonance studies of size-dependent spin dynamics in the absence of lithographic confinement in both ferromagnets and paramagnets reveal the close relationship between spin transport and spin lifetime at microscopic length scales. Finally, detection of ferromagnetic resonance of a ferromagnetic film using the photoluminescence of nitrogen vacancy spins in neighboring nanodiamonds demonstrates long-range spin transport between insulating materials, indicating the complexity and generality of spin transport in diverse, spatially separated, material systems

  12. Spinning charged test particles and Cosmic Censorship

    International Nuclear Information System (INIS)

    Caderni, N.; Calvani, M.

    1979-01-01

    The authors consider spinning charged test particles in the gravitational field of a rotating charged black hole, and it is shown that the hole cannot be destroyed, according to the Cosmic Censorship hypothesis. (Auth.)

  13. Inhomogeneous nuclear spin polarization induced by helicity-modulated optical excitation of fluorine-bound electron spins in ZnSe

    Science.gov (United States)

    Heisterkamp, F.; Greilich, A.; Zhukov, E. A.; Kirstein, E.; Kazimierczuk, T.; Korenev, V. L.; Yugova, I. A.; Yakovlev, D. R.; Pawlis, A.; Bayer, M.

    2015-12-01

    Optically induced nuclear spin polarization in a fluorine-doped ZnSe epilayer is studied by time-resolved Kerr rotation using resonant excitation of donor-bound excitons. Excitation with helicity-modulated laser pulses results in a transverse nuclear spin polarization, which is detected as a change of the Larmor precession frequency of the donor-bound electron spins. The frequency shift in dependence on the transverse magnetic field exhibits a pronounced dispersion-like shape with resonances at the fields of nuclear magnetic resonance of the constituent zinc and selenium isotopes. It is studied as a function of external parameters, particularly of constant and radio frequency external magnetic fields. The width of the resonance and its shape indicate a strong spatial inhomogeneity of the nuclear spin polarization in the vicinity of a fluorine donor. A mechanism of optically induced nuclear spin polarization is suggested based on the concept of resonant nuclear spin cooling driven by the inhomogeneous Knight field of the donor-bound electron.

  14. Reynolds-Stress and Triple-Product Models Applied to Flows with Rotation and Curvature

    Science.gov (United States)

    Olsen, Michael E.

    2016-01-01

    Predictions for Reynolds-stress and triple product turbulence models are compared for flows with significant rotational effects. Driver spinning cylinder flowfield and Zaets rotating pipe case are to be investigated at a minimum.

  15. Electrically tunable spin polarization in silicene: A multi-terminal spin density matrix approach

    International Nuclear Information System (INIS)

    Chen, Son-Hsien

    2016-01-01

    Recent realized silicene field-effect transistor yields promising electronic applications. Using a multi-terminal spin density matrix approach, this paper presents an analysis of the spin polarizations in a silicene structure of the spin field-effect transistor by considering the intertwined intrinsic and Rashba spin–orbit couplings, gate voltage, Zeeman splitting, as well as disorder. Coexistence of the stagger potential and intrinsic spin–orbit coupling results in spin precession, making any in-plane polarization directions reachable by the gate voltage; specifically, the intrinsic coupling allows one to electrically adjust the in-plane components of the polarizations, while the Rashba coupling to adjust the out-of-plan polarizations. Larger electrically tunable ranges of in-plan polarizations are found in oppositely gated silicene than in the uniformly gated silicene. Polarizations in different phases behave distinguishably in weak disorder regime, while independent of the phases, stronger disorder leads to a saturation value. - Highlights: • Density matrix with spin rotations enables multi-terminal arbitrary spin injections. • Gate-voltage tunable in-plane polarizations require intrinsic SO coupling. • Gate-voltage tunable out-of-plane polarizations require Rashba SO coupling. • Oppositely gated silicene yields a large tunable range of in-plan polarizations. • Polarizations in different phases behave distinguishably only in weak disorder.

  16. Spherical neutron polarimetry applied to spin-echo and time-of-flight spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lelievre-Berna, E., E-mail: lelievre@ill.e [Institut Laue Langevin (ILL), 6 rue Jules Horowitz, 38042 Grenoble Cedex 9 (France); Bentley, P.; Bourgeat-Lami, E.; Thomas, M. [Institut Laue Langevin (ILL), 6 rue Jules Horowitz, 38042 Grenoble Cedex 9 (France); Pappas, C. [Helmholtz Centre Berlin for Materials and Energy (HCB), Glienickerstr. 100, 14109 Berlin (Germany); Faculty of Applied Sciences, Delft University of Technology, Mekelweg 15, 2629 JB Delft (Netherlands); Kischnik, R.; Moskvin, E. [Helmholtz Centre Berlin for Materials and Energy (HCB), Glienickerstr. 100, 14109 Berlin (Germany)

    2009-09-01

    The changes in direction of the neutron spin that take place on scattering by a magnetic interaction vector are highly dependent on their relative directions. In some circumstances, without zero-field polarimeter, it is impossible to distinguish between a simple depolarisation and a rotation of the polarisation vector. Motivated by the investigation of chiral magnetic fluctuations, we have implemented the third-generation zero-field polarimeter Cryopad on the neutron spin-echo spectrometer SPAN at the Helmholtz Centre Berlin (HCB). We present the method and the limitations of this novel technique that is now available on IN15 at the ILL. The huge progress accomplished with {sup 3}He neutron spin filters/flippers are going to facilitate the exploitation of polarised beams at spallation sources. Zero-field polarimeters like Cryopad are used routinely at several steady-state sources but their design would be inefficient at a pulse source. We have investigated the possibility to implement a zero-field polarimeter on a time-of-flight spectrometer. We propose a design that would lead to a better efficiency and present the finite element calculations.

  17. EVOLUTION OF SPINNING AND BRAIDING HELICITY FLUXES IN SOLAR ACTIVE REGION NOAA 10930

    Energy Technology Data Exchange (ETDEWEB)

    Ravindra, B. [Indian Institute of Astrophysics, Koramangala, Bangalore 560 034 (India); Yoshimura, Keiji [Department of Physics, Montana State University Bozeman, MT 59717 (United States); Dasso, Sergio, E-mail: ravindra@iiap.res.in, E-mail: yosimura@solar.physics.montana.edu, E-mail: dasso@df.uba.ar [Instituto de Astronomia y Fisica del Espacio (CONICET-UBA), 1428 Buenos Aires (Argentina)

    2011-12-10

    The line-of-sight magnetograms from Solar Optical Telescope Narrowband Filter Imager observations of NOAA Active Region 10930 have been used to study the evolution of spinning and braiding helicities over a period of five days starting from 2006 December 9. The north (N) polarity sunspot was the follower and the south (S) polarity sunspot was the leader. The N-polarity sunspot in the active region was rotating in the counterclockwise direction. The rate of rotation was small during the first two days of observations and it increased up to 8 Degree-Sign hr{sup -1} on the third day of the observations. On the fourth and fifth days it remained at 4 Degree-Sign hr{sup -1} with small undulations in its magnitude. The sunspot rotated about 260 Degree-Sign in the last three days. The S-polarity sunspot did not complete more than 20 Degree-Sign in five days. However, it changed its direction of rotation five times over a period of five days and injected both the positive and negative type of spin helicity fluxes into the corona. Through the five days, both the positive and negative sunspot regions injected equal amounts of spin helicity. The total injected helicity is predominantly negative in sign. However, the sign of the spin and braiding helicity fluxes computed over all the regions were reversed from negative to positive five times during the five-day period of observations. The reversal in spinning helicity flux was found before the onset of the X3.4-class flare, too. Though, the rotating sunspot has been observed in this active region, the braiding helicity has contributed more to the total accumulated helicity than the spinning helicity. The accumulated helicity is in excess of -7 Multiplication-Sign 10{sup 43} Mx{sup 2} over a period of five days. Before the X3.4-class flare that occurred on 2006 December 13, the rotation speed and spin helicity flux increased in the S-polarity sunspot. Before the flare, the total injected helicity was larger than -6

  18. Evolution of nuclear collectivity at high spins and temperatures

    International Nuclear Information System (INIS)

    Baktash, C.

    1989-01-01

    In the past few years, we have utilized the Spin Spectrometer and a variety of complementary probes (continuum γrays, proton-γ coincidence spectroscopy and γ decay of GDR) to study the nuclear response to the DIFFERENTIAL effects of increasing spin and temperature for constant values of excitation energy or spin, respectively. In this paper we shall describe two of the experiments that trace the properties of rapidly-rotating nuclei at small to moderate excitation energies. 22 refs., 7 figs

  19. Rotational population patterns and searches for the nuclear SQUID (Superconducting Quantum Interference Device)

    International Nuclear Information System (INIS)

    Canto, L.F.; Donangelo, R.J.; Farhan, A.R.; Guidry, M.W.; Rasmussen, J.O.; Ring, P.; Stoyer, M.A.

    1989-11-01

    This paper presents new theoretical results for rotational population patterns in the nuclear SQUID effect. (The term nuclear SQUID is in analogy to the solid-state Superconducting Quantum Interference Devices.) The SQUID effect is an interesting new twist to an old quest to understand Coriolis anti-pairing (CAP) effects in nuclear rotational bands. Two-neutron transfer reaction cross sections among high-spin states have long been touted as more specific CAP probes than other nuclear properties. Heavy projectiles like Sn or Pb generally are recommended to pump the deformed nucleus to as high spin as possible for transfer. The interference and sign reversal of 2n transfer amplitudes at high spin, as predicted in the early SQUID work imposes the difficult requirement of Coulomb pumping to near back-bending spins at closest approach. For Pb on rare earths we find a dramatic departure from sudden-approximation, so that the population depression occurs as low as final spin 10h. 14 refs., 8 figs

  20. Interplay between tilted and principal axis rotation

    Energy Technology Data Exchange (ETDEWEB)

    Datta, Pradip [Ananda Mohan College, 102/1 Raja Rammohan Sarani, Kolkata 700 009 (India); Roy, Santosh; Chattopadhyay, S. [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata 700 064 (India)

    2014-08-14

    At IUAC-INGA, our group has studied four neutron rich nuclei of mass-110 region, namely {sup 109,110}Ag and {sup 108,110}Cd. These nuclei provide the unique platform to study the interplay between Tilted and Principal axis rotation since these are moderately deformed and at the same time, shears structures are present at higher spins. The salient features of the high spin behaviors of these nuclei will be discussed which are the signatures of this interplay.

  1. Interplay between tilted and principal axis rotation

    International Nuclear Information System (INIS)

    Datta, Pradip; Roy, Santosh; Chattopadhyay, S.

    2014-01-01

    At IUAC-INGA, our group has studied four neutron rich nuclei of mass-110 region, namely 109,110 Ag and 108,110 Cd. These nuclei provide the unique platform to study the interplay between Tilted and Principal axis rotation since these are moderately deformed and at the same time, shears structures are present at higher spins. The salient features of the high spin behaviors of these nuclei will be discussed which are the signatures of this interplay

  2. SPIN–SPIN COUPLING IN THE SOLAR SYSTEM

    International Nuclear Information System (INIS)

    Batygin, Konstantin; Morbidelli, Alessandro

    2015-01-01

    The richness of dynamical behavior exhibited by the rotational states of various solar system objects has driven significant advances in the theoretical understanding of their evolutionary histories. An important factor that determines whether a given object is prone to exhibiting non-trivial rotational evolution is the extent to which such an object can maintain a permanent aspheroidal shape, meaning that exotic behavior is far more common among the small body populations of the solar system. Gravitationally bound binary objects constitute a substantial fraction of asteroidal and TNO populations, comprising systems of triaxial satellites that orbit permanently deformed central bodies. In this work, we explore the rotational evolution of such systems with specific emphasis on quadrupole–quadrupole interactions, and show that for closely orbiting, highly deformed objects, both prograde and retrograde spin–spin resonances naturally arise. Subsequently, we derive capture probabilities for leading order commensurabilities and apply our results to the illustrative examples of (87) Sylvia and (216) Kleopatra asteroid systems. Cumulatively, our results suggest that spin–spin coupling may be consequential for highly elongated, tightly orbiting binary objects

  3. SPIN–SPIN COUPLING IN THE SOLAR SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    Batygin, Konstantin [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125 (United States); Morbidelli, Alessandro, E-mail: kbatygin@gps.caltech.edu [Departement Lagrange, Observatoire de la Côte d’Azur, F-06304 Nice (France)

    2015-09-10

    The richness of dynamical behavior exhibited by the rotational states of various solar system objects has driven significant advances in the theoretical understanding of their evolutionary histories. An important factor that determines whether a given object is prone to exhibiting non-trivial rotational evolution is the extent to which such an object can maintain a permanent aspheroidal shape, meaning that exotic behavior is far more common among the small body populations of the solar system. Gravitationally bound binary objects constitute a substantial fraction of asteroidal and TNO populations, comprising systems of triaxial satellites that orbit permanently deformed central bodies. In this work, we explore the rotational evolution of such systems with specific emphasis on quadrupole–quadrupole interactions, and show that for closely orbiting, highly deformed objects, both prograde and retrograde spin–spin resonances naturally arise. Subsequently, we derive capture probabilities for leading order commensurabilities and apply our results to the illustrative examples of (87) Sylvia and (216) Kleopatra asteroid systems. Cumulatively, our results suggest that spin–spin coupling may be consequential for highly elongated, tightly orbiting binary objects.

  4. RHIC spin flipper AC dipole controller

    Energy Technology Data Exchange (ETDEWEB)

    Oddo, P.; Bai, M.; Dawson, C.; Gassner, D.; Harvey, M.; Hayes, T.; Mernick, K.; Minty, M.; Roser, T.; Severino, F.; Smith, K.

    2011-03-28

    The RHIC Spin Flipper's five high-Q AC dipoles which are driven by a swept frequency waveform require precise control of phase and amplitude during the sweep. This control is achieved using FPGA based feedback controllers. Multiple feedback loops are used to and dynamically tune the magnets. The current implementation and results will be presented. Work on a new spin flipper for RHIC (Relativistic Heavy Ion Collider) incorporating multiple dynamically tuned high-Q AC-dipoles has been developed for RHIC spin-physics experiments. A spin flipper is needed to cancel systematic errors by reversing the spin direction of the two colliding beams multiple times during a store. The spin flipper system consists of four DC-dipole magnets (spin rotators) and five AC-dipole magnets. Multiple AC-dipoles are needed to localize the driven coherent betatron oscillation inside the spin flipper. Operationally the AC-dipoles form two swept frequency bumps that minimize the effect of the AC-dipole dipoles outside of the spin flipper. Both AC bumps operate at the same frequency, but are phase shifted from each other. The AC-dipoles therefore require precise control over amplitude and phase making the implementation of the AC-dipole controller the central challenge.

  5. Dynamical pairing correlations in rotating nuclei

    International Nuclear Information System (INIS)

    Szymanski, Z.

    1985-01-01

    When the atomic nucleus rotates fast enough the static pair correlations may be destroyed. In this situation the pair-vibrations become an important manifestation of the short-range attractive pairing force. The influence of this effect on nuclear properties at high spin is discussed. (orig.)

  6. Charges in nonlinear higher-spin theory

    Energy Technology Data Exchange (ETDEWEB)

    Didenko, V.E. [I.E. Tamm Department of Theoretical Physics, Lebedev Physical Institute,Leninsky prospect 53, 119991, Moscow (Russian Federation); Misuna, N.G. [I.E. Tamm Department of Theoretical Physics, Lebedev Physical Institute,Leninsky prospect 53, 119991, Moscow (Russian Federation); Moscow Institute of Physics and Technology,Institutsky lane 9, 141700, Dolgoprudny, Moscow region (Russian Federation); Vasiliev, M.A. [I.E. Tamm Department of Theoretical Physics, Lebedev Physical Institute,Leninsky prospect 53, 119991, Moscow (Russian Federation)

    2017-03-30

    Nonlinear higher-spin equations in four dimensions admit a closed two-form that defines a gauge-invariant global charge as an integral over a two-dimensional cycle. In this paper we argue that this charge gives rise to partitions depending on various lower- and higher-spin chemical potentials identified with modules of topological fields in the theory. The vacuum contribution to the partition is calculated to the first nontrivial order for a solution to higher-spin equations that generalizes AdS{sub 4} Kerr black hole of General Relativity. The resulting partition is non-zero being in parametric agreement with the ADM-like behavior of a rotating source. The linear response of chemical potentials to the partition function is also extracted. The explicit unfolded form of 4d GR black holes is given. An explicit formula relating asymptotic higher-spin charges expressed in terms of the generalized higher-spin Weyl tensor with those expressed in terms of Fronsdal fields is obtained.

  7. Charges in nonlinear higher-spin theory

    International Nuclear Information System (INIS)

    Didenko, V.E.; Misuna, N.G.; Vasiliev, M.A.

    2017-01-01

    Nonlinear higher-spin equations in four dimensions admit a closed two-form that defines a gauge-invariant global charge as an integral over a two-dimensional cycle. In this paper we argue that this charge gives rise to partitions depending on various lower- and higher-spin chemical potentials identified with modules of topological fields in the theory. The vacuum contribution to the partition is calculated to the first nontrivial order for a solution to higher-spin equations that generalizes AdS 4 Kerr black hole of General Relativity. The resulting partition is non-zero being in parametric agreement with the ADM-like behavior of a rotating source. The linear response of chemical potentials to the partition function is also extracted. The explicit unfolded form of 4d GR black holes is given. An explicit formula relating asymptotic higher-spin charges expressed in terms of the generalized higher-spin Weyl tensor with those expressed in terms of Fronsdal fields is obtained.

  8. Spin-orbit scattering in superconducting nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Alhassid, Y. [Center for Theoretical Physics, Sloane Physics Laboratory, Yale University, New Haven, Connecticut, 06520 (United States); Nesterov, K.N. [Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin, 53706 (United States)

    2017-06-15

    We review interaction effects in chaotic metallic nanoparticles. Their single-particle Hamiltonian is described by the proper random-matrix ensemble while the dominant interaction terms are invariants under a change of the single-particle basis. In the absence of spin-orbit scattering, the nontrivial invariants consist of a pairing interaction, which leads to superconductivity in the bulk, and a ferromagnetic exchange interaction. Spin-orbit scattering breaks spin-rotation invariance and when it is sufficiently strong, the only dominant nontrivial interaction is the pairing interaction. We discuss how the magnetic response of discrete energy levels of the nanoparticle (which can be measured in single-electron tunneling spectroscopy experiments) is affected by such pairing correlations and how it can provide a signature of pairing correlations. We also consider the spin susceptibility of the nanoparticle and discuss how spin-orbit scattering changes the signatures of pairing correlations in this observable. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  9. Spin tomography

    Energy Technology Data Exchange (ETDEWEB)

    D' Ariano, G M [Quantum Optics and Information Group, INFM Udr Pavia, Dipartimento di Fisica ' Alessandro Volta' and INFM, Via Bassi 6, 27100 Pavia (Italy); Maccone, L [Quantum Optics and Information Group, INFM Udr Pavia, Dipartimento di Fisica ' Alessandro Volta' and INFM, Via Bassi 6, 27100 Pavia (Italy); Paini, M [Quantum Optics and Information Group, INFM Udr Pavia, Dipartimento di Fisica ' Alessandro Volta' and INFM, Via Bassi 6, 27100 Pavia (Italy)

    2003-02-01

    We propose a tomographic reconstruction scheme for spin states. The experimental set-up, which is a modification of the Stern-Gerlach scheme, can be easily performed with currently available technology. The method is generalized to multiparticle states, analysing the spin-1/2 case for indistinguishable particles. Some Monte Carlo numerical simulations are given to illustrate the technique.

  10. Spin tomography

    International Nuclear Information System (INIS)

    D'Ariano, G M; Maccone, L; Paini, M

    2003-01-01

    We propose a tomographic reconstruction scheme for spin states. The experimental set-up, which is a modification of the Stern-Gerlach scheme, can be easily performed with currently available technology. The method is generalized to multiparticle states, analysing the spin-1/2 case for indistinguishable particles. Some Monte Carlo numerical simulations are given to illustrate the technique

  11. A rapid decrease in the rotation rate of comet 41P/Tuttle-Giacobini-Kresák.

    Science.gov (United States)

    Bodewits, Dennis; Farnham, Tony L; Kelley, Michael S P; Knight, Matthew M

    2018-01-10

    Cometary outgassing can produce torques that change the spin state of the cometary nucleus, which in turn influences the evolution and lifetime of the comet. If these torques increase the rate of rotation to the extent that centripetal forces exceed the material strength of the nucleus, the comet can fragment. Torques that slow down the rotation can cause the spin state to become unstable, but if the torques persist the nucleus can eventually reorient itself and the rotation rate can increase again. Simulations predict that most comets go through a short phase of rapid changes in spin state, after which changes occur gradually over longer times. Here we report observations of comet 41P/Tuttle-Giacobini-Kresák during its close approach to Earth (0.142 astronomical units, approximately 21 million kilometres, on 1 April 2017) that reveal a rapid decrease in rotation rate. Between March and May 2017, the apparent rotation period of the nucleus increased from 20 hours to more than 46 hours-a rate of change of more than an order of magnitude larger than has hitherto been measured. This phenomenon must have been caused by the gas emission from the comet aligning in such a way that it produced an anomalously strong torque that slowed the spin rate of the nucleus. The behaviour of comet 41P/Tuttle-Giacobini-Kresák suggests that it is in a distinct evolutionary state and that its rotation may be approaching the point of instability.

  12. A rapid decrease in the rotation rate of comet 41P/Tuttle–Giacobini–Kresák

    Science.gov (United States)

    Bodewits, Dennis; Farnham, Tony L.; Kelley, Michael S. P.; Knight, Matthew M.

    2018-01-01

    Cometary outgassing can produce torques that change the spin state of the cometary nucleus, which in turn influences the evolution and lifetime of the comet. If these torques increase the rate of rotation to the extent that centripetal forces exceed the material strength of the nucleus, the comet can fragment. Torques that slow down the rotation can cause the spin state to become unstable, but if the torques persist the nucleus can eventually reorient itself and the rotation rate can increase again. Simulations predict that most comets go through a short phase of rapid changes in spin state, after which changes occur gradually over longer times. Here we report observations of comet 41P/Tuttle–Giacobini–Kresák during its close approach to Earth (0.142 astronomical units, approximately 21 million kilometres, on 1 April 2017) that reveal a rapid decrease in rotation rate. Between March and May 2017, the apparent rotation period of the nucleus increased from 20 hours to more than 46 hours—a rate of change of more than an order of magnitude larger than has hitherto been measured. This phenomenon must have been caused by the gas emission from the comet aligning in such a way that it produced an anomalously strong torque that slowed the spin rate of the nucleus. The behaviour of comet 41P/Tuttle–Giacobini–Kresák suggests that it is in a distinct evolutionary state and that its rotation may be approaching the point of instability.

  13. Transient flows occurring during the accelerated crucible rotation technique

    International Nuclear Information System (INIS)

    Horowitz, Atara; Horowitz, Yigal

    1992-11-01

    The transient flows occurring after a change in the angular velocity of the cylindrical container are described. The dependence of the transient (known as spin-up or spin-down time) on experimental parameters as kinematic viscosity, cylinder dimensions and the cylinder's initial and final angular velocities are elucidates by a review of the literature. It is emphasized that with large Rossby numbers the spin-up time is longer and the amount of fluid mixing is greater than small and moderate Rossby numbers. It is also elucidated that most crystal growth crucibles cannot be considered as infinitely-long cylinders for the evaluation of the fluid dynamics (authors)

  14. Spin currents in metallic nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Czeschka, Franz Dominik

    2011-09-05

    A pure spin current, i.e., a flow of angular momentum without accompanying net charge current, is a key ingredient in the field of spintronics. In this thesis, we experimentally investigated two different concepts for pure spin current sources suggested by theory. The first is based on a time-dependent magnetization precession which ''pumps'' a pure spin current into an adjacent non-magnetic conductor. Our experiments quantitatively corroborated important predictions expected theoretically for this approach, including the dependence of the spin current on the sample geometry and the microwave power. Even more important, we could show for the first time that the spin pumping concept is viable in a large variety of ferromagnetic materials and that it only depends on the magnetization damping. Therefore, our experiments established spin pumping as generic phenomenon and demonstrated that it is a powerful way to generate pure spin currents. The second theoretical concept is based on the conversion of charge currents into spin currents in non-magnetic nanostructures via the spin Hall effect. We experimentally investigated this approach in H-shaped, metallic nanodevices, and found that the predictions are linked to requirements not realizable with the present experimental techniques, neither in sample fabrication nor in measurement technique. Indeed, our experimental data could be consistently understood by a spin-independent transport model describing the transition from diffusive to ballistic transport. In addition, the implementation of advanced fabrication and measurement techniques allowed to discover a new non-local phenomenon, the non-local anisotropic magnetoresistance. Finally, we also studied spin-polarized supercurrents carried by spin-triplet Cooper pairs. We found that low resistance interfaces are a key requirement for further experiments in this direction. (orig.)

  15. Spin-down of radio millisecond pulsars at genesis.

    Science.gov (United States)

    Tauris, Thomas M

    2012-02-03

    Millisecond pulsars are old neutron stars that have been spun up to high rotational frequencies via accretion of mass from a binary companion star. An important issue for understanding the physics of the early spin evolution of millisecond pulsars is the impact of the expanding magnetosphere during the terminal stages of the mass-transfer process. Here, I report binary stellar evolution calculations that show that the braking torque acting on a neutron star, when the companion star decouples from its Roche lobe, is able to dissipate >50% of the rotational energy of the pulsar. This effect may explain the apparent difference in observed spin distributions between x-ray and radio millisecond pulsars and help account for the noticeable age discrepancy with their young white dwarf companions.

  16. High spin structures in 194Hg

    International Nuclear Information System (INIS)

    Fotiades, N.; Vlastou, R.; Serris, M.; Sharpey-Schafer, J.F.; Fallon, P.; Riley, M.A.; Clark, R.M.; Hauschild, K.; Wadsworth, R.

    1996-01-01

    High spin states in the isotope 194 Hg were populated using the 150 Nd( 48 Ca,4n) reaction at a beam energy of 213 MeV. The analysis of γ-γ coincidences has revealed two new structures at excitation energies above 6 MeV and at moderate spin. The two structures are a manifestation of the deviation of nucleus from the collective rotation which dominates its lower excitation behaviour. A comparison with similar structures in the neighbouring Hg isotopes is also attempted. (orig.)

  17. Evidence of nontermination of collective rotation near the maximum angular momentum in Rb75

    Science.gov (United States)

    Davies, P. J.; Afanasjev, A. V.; Wadsworth, R.; Andreoiu, C.; Austin, R. A. E.; Carpenter, M. P.; Dashdorj, D.; Finlay, P.; Freeman, S. J.; Garrett, P. E.; Görgen, A.; Greene, J.; Grinyer, G. F.; Hyland, B.; Jenkins, D. G.; Johnston-Theasby, F. L.; Joshi, P.; Macchiavelli, A. O.; Moore, F.; Mukherjee, G.; Phillips, A. A.; Reviol, W.; Sarantites, D.; Schumaker, M. A.; Seweryniak, D.; Smith, M. B.; Svensson, C. E.; Valiente-Dobon, J. J.; Ward, D.

    2010-12-01

    Two of the four known rotational bands in Rb75 were studied via the Ca40(Ca40,αp)Rb75 reaction at a beam energy of 165 MeV. Transitions were observed up to the maximum spin Imax of the assigned configuration in one case and one-transition short of Imax in the other. Lifetimes were determined using the residual Doppler shift attenuation method. The deduced transition quadrupole moments show a small decrease with increasing spin, but remain large at the highest spins. The results obtained are in good agreement with cranked Nilsson-Strutinsky calculations, which indicate that these rotational bands do not terminate, but remain collective at Imax.

  18. Dynamic characterization, monitoring and control of rotating flexible beam-mass structures via piezo-embedded techniques

    Science.gov (United States)

    Lai, Steven H.-Y.

    1992-01-01

    A variational principle and a finite element discretization technique were used to derive the dynamic equations for a high speed rotating flexible beam-mass system embedded with piezo-electric materials. The dynamic equation thus obtained allows the development of finite element models which accommodate both the original structural element and the piezoelectric element. The solutions of finite element models provide system dynamics needed to design a sensing system. The characterization of gyroscopic effect and damping capacity of smart rotating devices are addressed. Several simulation examples are presented to validate the analytical solution.

  19. Spin diffusion in bulk GaN measured with MnAs spin injector

    KAUST Repository

    Jahangir, Shafat; Dogan, Fatih; Kum, Hyun; Manchon, Aurelien; Bhattacharya, Pallab

    2012-01-01

    Spin injection and precession in bulk wurtzite n-GaN with different doping densities are demonstrated with a ferromagnetic MnAs contact using the three-terminal Hanle measurement technique. Theoretical analysis using minimum fitting parameters indicates that the spin accumulation is primarily in the n-GaN channel rather than at the ferromagnet (FM)/semiconductor (SC) interface states. Spin relaxation in GaN is interpreted in terms of the D’yakonov-Perel mechanism, yielding a maximum spin lifetime of 44 ps and a spin diffusion length of 175 nm at room temperature. Our results indicate that epitaxial ferromagnetic MnAs is a suitable high-temperature spin injector for GaN.

  20. Spin diffusion in bulk GaN measured with MnAs spin injector

    KAUST Repository

    Jahangir, Shafat

    2012-07-16

    Spin injection and precession in bulk wurtzite n-GaN with different doping densities are demonstrated with a ferromagnetic MnAs contact using the three-terminal Hanle measurement technique. Theoretical analysis using minimum fitting parameters indicates that the spin accumulation is primarily in the n-GaN channel rather than at the ferromagnet (FM)/semiconductor (SC) interface states. Spin relaxation in GaN is interpreted in terms of the D’yakonov-Perel mechanism, yielding a maximum spin lifetime of 44 ps and a spin diffusion length of 175 nm at room temperature. Our results indicate that epitaxial ferromagnetic MnAs is a suitable high-temperature spin injector for GaN.

  1. The nucleon-nucleon spin-orbit interaction in the Skyrme model

    International Nuclear Information System (INIS)

    Riska, D.O.; Dannbom, K.

    1987-01-01

    The spin-orbit and quadratic spin-orbit components of the nucleon-nucleon interaction are derived in the Skyrme model at the classical level. These interaction components arise from the orbital and rotational motion of the soliton fields that form the nucleons. The isospin dependent part of the spin-orbit interaction is similar to the corresponding component obtained from boson exchange mechanisms at long distances although at short distances it is weaker. The isospin independent spin-orbit component is however different from the prediction of boson exchange mechanisms and has the opposite sign. The quadratic spin-orbit interaction is weak and has only an isospin dependent component

  2. Distributed quantum information processing via quantum dot spins

    International Nuclear Information System (INIS)

    Jun, Liu; Qiong, Wang; Le-Man, Kuang; Hao-Sheng, Zeng

    2010-01-01

    We propose a scheme to engineer a non-local two-qubit phase gate between two remote quantum-dot spins. Along with one-qubit local operations, one can in principal perform various types of distributed quantum information processing. The scheme employs a photon with linearly polarisation interacting one after the other with two remote quantum-dot spins in cavities. Due to the optical spin selection rule, the photon obtains a Faraday rotation after the interaction process. By measuring the polarisation of the final output photon, a non-local two-qubit phase gate between the two remote quantum-dot spins is constituted. Our scheme may has very important applications in the distributed quantum information processing

  3. Anisotropic interactions of a single spin and dark-spin spectroscopy in diamond

    Science.gov (United States)

    Epstein, R. J.; Mendoza, F. M.; Kato, Y. K.; Awschalom, D. D.

    2005-11-01

    Experiments on single nitrogen-vacancy (N-V) centres in diamond, which include electron spin resonance, Rabi oscillations, single-shot spin readout and two-qubit operations with a nearby13C nuclear spin, show the potential of this spin system for solid-state quantum information processing. Moreover, N-V centre ensembles can have spin-coherence times exceeding 50 μs at room temperature. We have developed an angle-resolved magneto-photoluminescence microscope apparatus to investigate the anisotropic electron-spin interactions of single N-V centres at room temperature. We observe negative peaks in the photoluminescence as a function of both magnetic-field magnitude and angle that are explained by coherent spin precession and anisotropic relaxation at spin-level anti-crossings. In addition, precise field alignment unmasks the resonant coupling to neighbouring `dark' nitrogen spins, otherwise undetected by photoluminescence. These results demonstrate the capability of our spectroscopic technique for measuring small numbers of dark spins by means of a single bright spin under ambient conditions.

  4. Spin inelastic electron tunneling spectroscopy on local spin adsorbed on surface.

    Science.gov (United States)

    Fransson, J

    2009-06-01

    The recent experimental conductance measurements taken on magnetic impurities on metallic surfaces, using scanning tunneling microscopy technique and suggesting occurrence of inelastic scattering processes, are theoretically addressed. We argue that the observed conductance signatures are caused by transitions between the spin states that have opened due to, for example, exchange coupling between the local spins and the tunneling electrons, and are directly interpretable in terms of inelastic transitions energies. Feasible measurements using spin-polarized scanning tunneling microscopy that would enable new information about the excitation spectrum of the local spins are discussed.

  5. Spin dynamics of large-spin fermions in a harmonic trap

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Junjun; Feng, Tongtong; Gu, Qiang, E-mail: qgu@ustb.edu.cn

    2017-04-15

    Understanding the collective dynamics in a many-body system has been a central task in condensed matter physics. To achieve this task, we develop a Hartree–Fock theory to study the collective oscillations of spinor Fermi system, motivated by recent experiment on spin-9/2 fermions. We observe an oscillation period shoulder for small rotation angles. Different from previous studies, where the shoulder is found connected to the resonance from periodic to running phase, here the system is always in a running phase in the two-body phase space. This shoulder survives even in the many-body oscillations, which could be tested in the experiments. We also show how these collective oscillations evolve from two- to many-body. Our theory provides an alternative way to understand the collective dynamics in large-spin Fermi systems.

  6. New Methodology For Use in Rotating Field Nuclear MagneticResonance

    Energy Technology Data Exchange (ETDEWEB)

    Jachmann, Rebecca C. [Univ. of California, Berkeley, CA (United States)

    2007-01-01

    High-resolution NMR spectra of samples with anisotropicbroadening are simplified to their isotropic spectra by fast rotation ofthe sample at the magic angle 54.7 circ. This dissertation concerns thedevelopment of novel Nuclear Magnetic Resonance (NMR) methodologies basedwhich would rotate the magnetic field instead of the sample, rotatingfield NMR. It provides an over of the NMR concepts, procedures, andexperiments needed to understand the methodologies that will be used forrotating field NMR. A simple two-dimensional shimming method based onharmonic corrector rings which can provide arbitrary multiple ordershimming corrections were developed for rotating field systems, but couldbe used in shimming other systems as well. Those results demonstrate, forexample, that quadrupolar order shimming improves the linewidth by up toan order of magnitude. An additional order of magnitude reduction is inprinciple achievable by utilizing this shimming method for z-gradientcorrection and higher order xy gradients. A specialized pulse sequencefor the rotating field NMR experiment is under development. The pulsesequence allows for spinning away from the magic angle and spinningslower than the anisotropic broadening. This pulse sequence is acombination of the projected magic angle spinning (p-MAS) and magic angleturning (MAT) pulse sequences. This will be useful to rotating field NMRbecause there are limits on how fast a field can be spun and spin at themagic angle is difficult. One of the goals of this project is forrotating field NMR to be used on biological systems. The p-MAS pulsesequence was successfully tested on bovine tissue samples which suggeststhat it will be a viable methodology to use in a rotating field set up. Aside experiment on steering magnetic particle by MRI gradients was alsocarried out. Some movement was seen in these experiment, but for totalcontrol over steering further experiments would need to bedone.

  7. New Methodology For Use in Rotating Field Nuclear MagneticResonance

    Energy Technology Data Exchange (ETDEWEB)

    Jachmann, Rebecca C. [Univ. of California, Berkeley, CA (United States)

    2007-05-18

    High-resolution NMR spectra of samples with anisotropicbroadening are simplified to their isotropic spectra by fast rotation ofthe sample at the magic angle 54.7 circ. This dissertation concerns thedevelopment of novel Nuclear Magnetic Resonance (NMR) methodologies basedwhich would rotate the magnetic field instead of the sample, rotatingfield NMR. It provides an over of the NMR concepts, procedures, andexperiments needed to understand the methodologies that will be used forrotating field NMR. A simple two-dimensional shimming method based onharmonic corrector rings which can provide arbitrary multiple ordershimming corrections were developed for rotating field systems, but couldbe used in shimming other systems as well. Those results demonstrate, forexample, that quadrupolar order shimming improves the linewidth by up toan order of magnitude. An additional order of magnitude reduction is inprinciple achievable by utilizing this shimming method for z-gradientcorrection and higher order xy gradients. A specialized pulse sequencefor the rotating field NMR experiment is under development. The pulsesequence allows for spinning away from the magic angle and spinningslower than the anisotropic broadening. This pulse sequence is acombination of the projected magic angle spinning (p-MAS) and magic angleturning (MAT) pulse sequences. This will be useful to rotating field NMRbecause there are limits on how fast a field can be spun and spin at themagic angle is difficult. One of the goals of this project is forrotating field NMR to be used on biological systems. The p-MAS pulsesequence was successfully tested on bovine tissue samples which suggeststhat it will be a viable methodology to use in a rotating field set up. Aside experiment on steering magnetic particle by MRI gradients was alsocarried out. Some movement was seen in these experiment, but for totalcontrol over steering further experiments would need to bedone.

  8. Measurement of small light absorption in microparticles by means of optically induced rotation

    DEFF Research Database (Denmark)

    Angelsky, O. V.; Bekshaev, A. Ya; Maksimyak, P. P.

    2015-01-01

    The absorption parameters of micro-particles have been associated with the induced spin exerted upon the particle, when embedded in a circularly polarized coherent field. The induced rotational speed is theoretically analyzed, showing the influence of the beam parameters, the parameters of the pa......The absorption parameters of micro-particles have been associated with the induced spin exerted upon the particle, when embedded in a circularly polarized coherent field. The induced rotational speed is theoretically analyzed, showing the influence of the beam parameters, the parameters...

  9. Gyrochronology of Low-mass Stars - Age-Rotation-Activity Relations for Young M Dwarfs

    Science.gov (United States)

    Kidder, Benjamin; Shkolnik, E.; Skiff, B.

    2014-01-01

    New rotation periods for 34 young understanding of the underlying mechanisms that govern angular momentum evolution. Yet, on average, the data still support the predicted trends for spin-up during contraction and spin-down on the main sequence, with the turnover occurring at around 150 Myr for early Ms. This suggests that rotation period distributions can be helpful in evaluating the ages of coeval groups of stars. Many thanks to the National Science Foundation for their support through the Research Experience for Undergraduates Grant AST- 1004107.

  10. Nuclear-spin-dependent parity-nonconserving effects in thallium, lead and bismuth atoms

    International Nuclear Information System (INIS)

    Khriplovich, I.B.

    1994-01-01

    Nuclear-spin-dependent P-odd optical activity in atomic Tl, Pb and Bi is calculated. Its magnitude is expressed analytically through the main contribution to the optical rotation, which is independent of nuclear spin. The accuracy of results is discussed. 31 refs., 2 tabs

  11. Exchange-Mediated Contrast in CEST and Spin-Lock Imaging

    Science.gov (United States)

    Cobb, Jared Guthrie; Li, Ke; Xie, Jingping; Gochberg, Daniel F.; Gore, John C.

    2014-01-01

    PURPOSE Magnetic resonance images of biological media based on chemical exchange saturation transfer (CEST) show contrast that depends on chemical exchange between water and other protons. In addition, spin-lattice relaxation rates in the rotating frame (R1ρ) are also affected by exchange, especially at high fields, and can be exploited to provide novel, exchange-dependent contrast. Here, we evaluate and compare the factors that modulate the exchange contrast for these methods using simulations and experiments on simple, biologically relevant samples. METHODS Simulations and experimental measurements at 9.4T of rotating frame relaxation rate dispersion and CEST contrast were performed on solutions of macromolecules containing amide and hydroxyl exchanging protons. RESULTS The simulations and experimental measurements confirm that both CEST and R1ρ measurements depend on similar exchange parameters, but they manifest themselves differently in their effects on contrast. CEST contrast may be larger in the slow and intermediate exchange regimes for protons with large resonant frequency offsets (e.g. > 2ppm). Spin-locking techniques can produce larger contrast enhancement when resonant frequency offsets are small (exchange is in the intermediate to fast regime. The image contrasts scale differently with field strength, exchange rate and concentration. CONCLUSION CEST and R1ρ measurements provide different and somewhat complementary information about exchange in tissues. Whereas CEST can depict exchange of protons with specific chemical shifts, appropriate R1ρ dependent acquisitions can be employed to selectively portray protons of specific exchange rates. PMID:24239335

  12. Exchange-mediated contrast in CEST and spin-lock imaging.

    Science.gov (United States)

    Cobb, Jared Guthrie; Li, Ke; Xie, Jingping; Gochberg, Daniel F; Gore, John C

    2014-01-01

    Magnetic resonance images of biological media based on chemical exchange saturation transfer (CEST) show contrast that depends on chemical exchange between water and other protons. In addition, spin-lattice relaxation rates in the rotating frame (R1ρ) are also affected by exchange, especially at high fields, and can be exploited to provide novel, exchange-dependent contrast. Here, we evaluate and compare the factors that modulate the exchange contrast for these methods using simulations and experiments on simple, biologically relevant samples. Simulations and experimental measurements at 9.4 T of rotating frame relaxation rate dispersion and CEST contrast were performed on solutions of macromolecules containing amide and hydroxyl exchanging protons. The simulations and experimental measurements confirm that both CEST and R1ρ measurements depend on similar exchange parameters, but they manifest themselves differently in their effects on contrast. CEST contrast may be larger in the slow and intermediate exchange regimes for protons with large resonant frequency offsets (e.g. >2 ppm). Spin-locking techniques can produce larger contrast enhancement when resonant frequency offsets are small (exchange is in the intermediate-to-fast regime. The image contrasts scale differently with field strength, exchange rate and concentration. CEST and R1ρ measurements provide different and somewhat complementary information about exchange in tissues. Whereas CEST can depict exchange of protons with specific chemical shifts, appropriate R1ρ-dependent acquisitions can be employed to selectively portray protons of specific exchange rates. © 2013.

  13. Lifetimes of high-spin states in {sup 162}Yb

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter, M.P.; Janssens, R.V.F.; Henry, R.G. [and others

    1995-08-01

    A measurement on lifetimes of high-spin states in the yrast and near-yrast rotational bands in {sup 162}Yb was carried out at ATLAS in order to determine the evolution of collectivity as a function of angular momentum using the {sup 126}Te({sup 40}Ar,4n){sup 162}Yb reaction at 170 MeV. Previous lifetime measurements in the {sup 164,166,168}Yb isotopes showed a dramatic decrease in the transition quadrupole moment Q{sub t} with increasing spin. It was suggested that this decrease in Q{sub t} is brought about by the rotationally-induced deoccupation of high-j configurations, mainly i{sub 13/2} neutrons. If this interpretation is correct, the heavier isotopes should have a larger decrease in Q{sub t} than the lighter mass nuclides due to the position of the Fermi surface in the i{sub 13/2} subshell. Indeed, {sup 160}Yb does not show a clear decrease in Q{sub t} at high spin. No high spin lifetime information exists for {sup 162}Yb, thus this experiment fills the gap of measured Q{sub t}`s in the light Yb series. The data is currently being analyzed.

  14. Non-adiabatic Landau-Zener transitions in low-spin molecular magnet V sub 1 sub 5

    CERN Document Server

    Chiorescu, I; Müller, A; Bögge, H; Barbara, B

    2000-01-01

    The V sub 1 sub 5 polyoxovanadate molecule is made of 15 spins ((1)/(2)) with antiferromagnetic couplings. It belongs to the class of molecules with very large Hilbert space dimension (2 sup 1 sup 5 in V sub 1 sub 5 , 10 sup 8 in Mn sub 1 sub 2 -AC). It is a low spin/large molecule with spin S=((1)/(2)). Contrary to large spins/large molecules of the Mn sub 1 sub 2 -AC type, V sub 1 sub 5 has no energy barrier against spin rotation. Magnetization measurements have been performed and despite the absence of a barrier, magnetic hysteresis is observed over a timescale of several seconds. This new phenomenon characterized by a 'butterfly' hysteresis loop is due to the effect of the environment on the quantum rotation of the entangled 15 spins of the molecule, in which the phonon density of states is not at its equilibrium (phonon bottleneck).

  15. Spin-reorientation magnetic transitions in Mn-doped SmFeO3

    Directory of Open Access Journals (Sweden)

    Jian Kang

    2017-09-01

    Full Text Available Spin reorientation is a magnetic phase transition in which rotation of the magnetization vector with respect to the crystallographic axes occurs upon a change in the temperature or magnetic field. For example, SmFeO3 shows a magnetization rotation from the c axis above 480 K to the a axis below 450 K, known as the Γ4 → Γ2 transition. This work reports the successful synthesis of the new single-crystal perovskite SmFe0.75Mn0.25O3 and finds interesting spin reorientations above and below room temperature. In addition to the spin reorientation of the Γ4 → Γ2 magnetic phase transition observed at around TSR2 = 382 K, a new spin reorientation, Γ2 → Γ1, was seen at around TSR1 = 212 K due to Mn doping, which could not be observed in the parent rare earth perovskite compound. This unexpected spin configuration has complete antiferromagnetic order without any canting-induced weak ferromagnetic moment, resulting in zero magnetization in the low-temperature regime. M–T and M–H measurements have been made to study the temperature and magnetic-field dependence of the observed spin reorientation transitions.

  16. Spin tracking for a deuteron EDM storage ring

    Science.gov (United States)

    Skawran, A.; Lehrach, A.

    2017-07-01

    The aim of the Jülich Electric Dipole moment Investigations (JEDI) collaboration is the measurement of the Electric Dipole Moment (EDM) of charged particles like protons or deuterons. There are two possible concepts under consideration for the realization of EDM measurement with deuterons; the Frozen Spin (FS) and Quasi-Frozen Spin (QFS) method. Both approaches are discussed and compared in this paper. Detailed spin- and beam dynamics simulations are performed to investigate the effect of various misalignments of ring elements and systematic effects. Furthermore, the utilization of counter rotating beams is studied and checked for its validity.

  17. Spin tracking for a deuteron EDM storage ring

    International Nuclear Information System (INIS)

    Skawran, A; Lehrach, A

    2017-01-01

    The aim of the Jülich Electric Dipole moment Investigations (JEDI) collaboration is the measurement of the Electric Dipole Moment (EDM) of charged particles like protons or deuterons. There are two possible concepts under consideration for the realization of EDM measurement with deuterons; the Frozen Spin (FS) and Quasi-Frozen Spin (QFS) method. Both approaches are discussed and compared in this paper. Detailed spin- and beam dynamics simulations are performed to investigate the effect of various misalignments of ring elements and systematic effects. Furthermore, the utilization of counter rotating beams is studied and checked for its validity. (paper)

  18. On the Terminal Rotation Rates of Giant Planets

    Science.gov (United States)

    Batygin, Konstantin

    2018-04-01

    Within the general framework of the core-nucleated accretion theory of giant planet formation, the conglomeration of massive gaseous envelopes is facilitated by a transient period of rapid accumulation of nebular material. While the concurrent build-up of angular momentum is expected to leave newly formed planets spinning at near-breakup velocities, Jupiter and Saturn, as well as super-Jovian long-period extrasolar planets, are observed to rotate well below criticality. In this work, we demonstrate that the large luminosity of a young giant planet simultaneously leads to the generation of a strong planetary magnetic field, as well as thermal ionization of the circumplanetary disk. The ensuing magnetic coupling between the planetary interior and the quasi-Keplerian motion of the disk results in efficient braking of planetary rotation, with hydrodynamic circulation of gas within the Hill sphere playing the key role of expelling spin angular momentum to the circumstellar nebula. Our results place early-stage giant planet and stellar rotation within the same evolutionary framework, and motivate further exploration of magnetohydrodynamic phenomena in the context of the final stages of giant planet formation.

  19. Physics of high spin nuclear states

    Energy Technology Data Exchange (ETDEWEB)

    Wyss, R [Joint Inst. for Heavy Ion Research, Oak Ridge, TN (United States); [MSI, Frescativ, Stockholm (Sweden)

    1992-08-01

    High spin physics is a vast topic addressing the variety of nuclear excitation modes. In the present paper, some general aspects related to recent highlights of nuclear spectroscopy are discussed. The relation between signature splitting and shape changes in the unique parity orbitals is elucidated. The relevance of the Pseudo SU(3) symmetry in the understanding of rotational band structure is addressed. Specific features of rotational bands of intruder configurations are viewed as a probe of the neutron-proton interaction. (author). 36 refs., 5 figs.

  20. Spin dynamics in high-mobility two-dimensional electron systems embedded in GaAs/AlGaAs quantum wells

    Energy Technology Data Exchange (ETDEWEB)

    Griesbeck, Michael

    2012-11-22

    Since many years there has been great effort to explore the spin dynamics in low-dimensional electron systems embedded in GaAs/AlGaAs based heterostructures for the purpose of quantum computation and spintronics applications. Advances in technology allow for the design of high quality and well-defined two-dimensional electron systems (2DES), which are perfectly suited for the study of the underlying physics that govern the dynamics of the electron spin system. In this work, spin dynamics in high-mobility 2DES is studied by means of the all-optical time-resolved Kerr/Faraday rotation technique. In (001)-grown 2DES, a strong in-plane spin dephasing anisotropy is studied, resulting from the interference of comparable Rashba and Dresselhaus contributions to the spin-orbit field (SOF). The dependence of this anisotropy on parameters like the confinement length of the 2DES, the sample temperature, as well as the electron density is demonstrated. Furthermore, coherent spin dynamics of an ensemble of ballistically moving electrons is studied without and within an applied weak magnetic field perpendicular to the sample plane, which forces the electrons to move on cyclotron orbits. Finally, strongly anisotropic spin dynamics is investigated in symmetric (110)-grown 2DES, using the resonant spin amplification method. Here, extremely long out-of-plane spin dephasing times can be achieved, in consequence of the special symmetry of the Dresselhaus SOF.

  1. Spin-spin correlations in the tt'-Hubbard model

    International Nuclear Information System (INIS)

    Husslein, T.; Newns, D.M.; Mattutis, H.G.; Pattnaik, P.C.; Morgenstern, I.; Singer, J.M.; Fettes, W.; Baur, C.

    1994-01-01

    We present calculations of the tt'-Hubbard model using Quantum Monte Carlo techniques. The parameters are chosen so that the van Hove Singularity in the density of states and the Fermi level coincide. We study the behaviour of the system with increasing Hubbard interaction U. Special emphasis is on the spin-spin correlation (SSC). Unusual behaviour for large U is observed there and in the momentum distribution function (n(q)). (orig.)

  2. Slow Manifold and Hannay Angle in the Spinning Top

    Science.gov (United States)

    Berry, M. V.; Shukla, P.

    2011-01-01

    The spin of a top can be regarded as a fast variable, coupled to the motion of the axis which is slow. In pure precession, the rotation of the axis round a cone (without nutation), can be considered as the result of a reaction from the fast spin. The resulting restriction of the total state space of the top is an illustrative example, at…

  3. Frame-dragging effect in the field of non rotating body due to unit gravimagnetic moment

    Science.gov (United States)

    Deriglazov, Alexei A.; Ramírez, Walberto Guzmán

    2018-04-01

    Nonminimal spin-gravity interaction through unit gravimagnetic moment leads to modified Mathisson-Papapetrou-Tulczyjew-Dixon equations with improved behavior in the ultrarelativistic limit. We present exact Hamiltonian of the resulting theory and compute an effective 1/c2-Hamiltonian and leading post-Newtonian corrections to the trajectory and spin. Gravimagnetic moment causes the same precession of spin S as a fictitious rotation of the central body with angular momentum J = M/m S. So the modified equations imply a number of qualitatively new effects, that could be used to test experimentally, whether a rotating body in general relativity has null or unit gravimagnetic moment.

  4. Instability of ultra-spinning black holes

    International Nuclear Information System (INIS)

    Emparan, Roberto; Myers, Robert C.

    2003-01-01

    It has long been known that, in higher-dimensional general relativity, there are black hole solutions with an arbitrarily large angular momentum for a fixed mass. We examine the geometry of the event horizon of such ultra-spinning black holes and argue that these solutions become unstable at large enough rotation. Hence we find that higher-dimensional general relativity imposes an effective 'Kerr-bound' on spinning black holes through a dynamical decay mechanism. Our results also give indications of the existence of new stationary black holes with 'rippled' horizons of spherical topology. We consider various scenarios for the possible decay of ultra-spinning black holes, and finally discuss the implications of our results for black holes in braneworld scenarios. (author)

  5. Semiconductors put spin in spintronics

    International Nuclear Information System (INIS)

    Weiss, Dieter

    2000-01-01

    Electrons and holes, which carry the current in semiconductor devices, are quantum-mechanical objects characterized by a set of quantum numbers - the band index, the wave-vector (which is closely related to the electron or hole velocity) and spin. The spin, however, is one of the strangest properties of particles. In simple terms, we can think of the spin as an internal rotation of the electron, but it has no classical counterpart. The spin is connected to a quantized magnetic moment and hence acts as a microscopic magnet. Thus the electron spin can adopt one of two directions (''up'' or ''down'') in a magnetic field. The spin plays no role in conventional electronics and the current in any semiconductor device is made up of a mixture of electrons with randomly oriented spins. However, a new range of electronic devices that transport the spin of the electrons, in addition to their charge, is being developed. But the biggest obstacle to making practical ''spin electronic'' or ''spintronic'' devices so far has been finding a way of injecting spin-polarized electrons or holes into the semiconductor and then detecting them. Recently a team of physicists from the University of Wuerzburg in Germany, and also a collaboration of researchers from Tohoku University in Japan and the University of California at Santa Barbara, have found a way round these problems using either semi-magnetic or ferromagnetic semiconductors as ''spin aligners'' (R Fiederling et al. 1999 Nature 402 787; Y Ohno et al. 1999 Nature 402 790). In this article the author presents the latest breakthrough in spintronics research. (UK)

  6. Field of first magnetic flux entry and pinning strength of superconductors for rf application measured with muon spin rotation

    Science.gov (United States)

    Junginger, T.; Abidi, S. H.; Maffett, R. D.; Buck, T.; Dehn, M. H.; Gheidi, S.; Kiefl, R.; Kolb, P.; Storey, D.; Thoeng, E.; Wasserman, W.; Laxdal, R. E.

    2018-03-01

    The performance of superconducting radiofrequency (SRF) cavities used for particle accelerators depends on two characteristic material parameters: field of first flux entry Hentry and pinning strength. The former sets the limit for the maximum achievable accelerating gradient, while the latter determines how efficiently flux can be expelled related to the maximum achievable quality factor. In this paper, a method based on muon spin rotation (μ SR ) is developed to probe these parameters on samples. It combines measurements from two different spectrometers, one being specifically built for these studies and samples of different geometries. It is found that annealing at 1400 °C virtually eliminates all pinning. Such an annealed substrate is ideally suited to measure Hentry of layered superconductors, which might enable accelerating gradients beyond bulk niobium technology.

  7. Efficient Spin Injection into Semiconductor

    International Nuclear Information System (INIS)

    Nahid, M.A.I.

    2010-06-01

    Spintronic research has made tremendous progress nowadays for making future devices obtain extra advantages of low power, and faster and higher scalability compared to present electronic devices. A spintronic device is based on the transport of an electron's spin instead of charge. Efficient spin injection is one of the very important requirements for future spintronic devices. However, the effective spin injection is an exceedingly difficult task. In this paper, the importance of spin injection, basics of spin current and the essential requirements of spin injection are illustrated. The experimental technique of electrical spin injection into semiconductor is also discussed based on the experimental experience. The electrical spin injection can easily be implemented for spin injection into any semiconductor. (author)

  8. Spin-exchange and spin-destruction rates for the 3He-Na system

    International Nuclear Information System (INIS)

    Borel, P.I.; Soegaard, L.V.; Svendsen, W.E.; Andersen, N.

    2003-01-01

    Optically pumped Na is used as a spin-exchange partner to polarize 3 He. Polarizations around 20% have routinely been achieved in sealed spherical glass cells containing 3 He, N 2 , and a few droplets of Na. An optical technique has been developed to determine the Na- 3 He spin-exchange rate coefficient. By monitoring the Na spin relaxation ''in the dark,'' the average Na-Na spin-destruction cross section at 330 degree sign C is estimated to be around 5x10 -19 cm 2 . This value is 2-5 (15-30) times smaller than the previously reported values for the K-K (Rb-Rb) spin-relaxation cross section. In the temperature range 310-355 degree sign C the spin-exchange rate coefficient is found to be (6.1±0.6)x10 -20 cm 3 /s with no detectable temperature dependence. This value is in good agreement with a previous theoretical estimate reported by Walker and it is only slightly lower than the corresponding Rb- 3 He spin-exchange rate coefficient. The total Na- 3 He spin-destruction rate coefficient is, within errors, found to be the same as the Na- 3 He spin-exchange rate coefficient, thereby indicating that the maximum possible photon efficiency may approach unity for the Na- 3 He system. A technique, in which a charge-coupled device camera is used to take images of faint unquenched fluorescence light, has been utilized to allow for an instantaneous determination of the sodium number densities during the rate coefficient measurements

  9. SDSS-IV MaNGA: a distinct mass distribution explored in slow-rotating early-type galaxies

    Science.gov (United States)

    Rong, Yu; Li, Hongyu; Wang, Jie; Gao, Liang; Li, Ran; Ge, Junqiang; Jing, Yingjie; Pan, Jun; Fernández-Trincado, J. G.; Valenzuela, Octavio; Ortíz, Erik Aquino

    2018-06-01

    We study the radial acceleration relation (RAR) for early-type galaxies (ETGs) in the SDSS MaNGA MPL5 data set. The complete ETG sample show a slightly offset RAR from the relation reported by McGaugh et al. (2016) at the low-acceleration end; we find that the deviation is due to the fact that the slow rotators show a systematically higher acceleration relation than the McGaugh's RAR, while the fast rotators show a consistent acceleration relation to McGaugh's RAR. There is a 1σ significant difference between the acceleration relations of the fast and slow rotators, suggesting that the acceleration relation correlates with the galactic spins, and that the slow rotators may have a different mass distribution compared with fast rotators and late-type galaxies. We suspect that the acceleration relation deviation of slow rotators may be attributed to more galaxy merger events, which would disrupt the original spins and correlated distributions of baryons and dark matter orbits in galaxies.

  10. Magnetic Field Studies in BL Lacertae through Faraday Rotation and a Novel Astrometric Technique

    Directory of Open Access Journals (Sweden)

    Sol N. Molina

    2017-12-01

    Full Text Available It is thought that dynamically important helical magnetic fields twisted by the differential rotation of the black hole’s accretion disk or ergosphere play an important role in the launching, acceleration, and collimation of active galactic nuclei (AGN jets. We present multi-frequency astrometric and polarimetric Very Long Baseline Array (VLBA images at 15, 22, and 43 GHz, as well as Faraday rotation analyses of the jet in BL Lacertae as part of a sample of AGN jets aimed to probe the magnetic field structure at the innermost scales to test jet formation models. The novel astrometric technique applied allows us to obtain the absolute position at mm wavelengths without any external calibrator.

  11. Phenomenological aspects of new gravitational forces. I. Rapidly rotating compact objects

    International Nuclear Information System (INIS)

    Nieto, M.M.; Goldman, T.; Hughes, R.J.

    1987-01-01

    A general phenomenological feature of theories of quantum gravity is the existence of spin-1 and spin-0 partners of the graviton, which are expected to be massive (have finite ranges). In the static limit, the forces associated with these partners could almost cancel for particle-particle interactions and yet still produce dramatic effects for antiparticle-particle interactions (such as the gravitational attraction of antiprotons to Earth). However, at relativistic velocities the new forces could become significant even for particle-particle interactions. In this paper we show how these partners could modify the dynamics of particles at the surface of rotating, compact objects, specifically, rapidly rotating pulsars

  12. Electron spin exchange of shallow donor muonium states

    International Nuclear Information System (INIS)

    Senba, Masayoshi

    2005-01-01

    Shallow donor muonium states with small hyperfine frequencies, recently observed in II-VI semiconductor compounds, have a number of unique features that present both opportunities and challenges in understanding muon spin dynamics in the presence of Heisenberg spin exchange. First, the shallow muonium state in CdSe with hyperfine frequency ω 0 /2π ∼ 0.1 MHz is already in the high field regime even in the earth's magnetic field, where only two precession frequencies are observable by the muon spin rotation (μSR) technique. Second, unlike in the case of more conventional muonium species with a larger hyperfine frequency, the μSR signal of shallow muonium states can be observed even in the transition region, between the slow spin-flip regime and the fast spin-flip regime, where the spin-flip rate and the hyperfine frequency are comparable. The muon spin dynamics in the transition region has not been theoretically explored previously, mainly because normal muonium in vacuum gives no observable signal in this region. Third, in the case of shallow muonium states, the incoherent process defined to be those spin-flip collisions that cause changes in muon spin precession frequencies, becomes crucially important in the transition region, where the incoherent process is entirely negligible in more conventional muonium species. By taking incoherent multiple collisions into account, an analytical expression for the time evolution of the muon spin polarization in Mu is derived, where Mu undergoes repeated spin-flip collisions. Comparisons with Monte Carlo calculations show that the analytical expression obtained in this work can reliably be used to analyse experimental data for shallow donor states not only in the slow spin-flip regime, but also in the transition region up to the onset of the fast regime. The present work confirms a recent experimental finding that, in the transition region, the initial phases of the two precession components of shallow donor states

  13. Double-decker phthalocyanine complex: Scanning tunneling microscopy study of film formation and spin properties

    Science.gov (United States)

    Komeda, Tadahiro; Katoh, Keiichi; Yamashita, Masahiro

    2014-05-01

    We review recent studies of double-decker and triple-decker phthalocyanine (Pc) molecules adsorbed on surfaces in terms of the bonding configuration, electronic structure and spin state. The Pc molecule has been studied extensively in surface science. A Pc molecule can contain various metal atoms at the center, and the class of the molecule is called as metal phthalocyanine (MPc). If the center metal has a large radius, like as lanthanoid metals, it becomes difficult to incorporate the metal atom inside of the Pc ring. Pc ligands are placed so as to sandwich the metal atom, where the metal atom is placed out of the Pc plane. The molecule in this configuration is called as a multilayer-decker Pc molecule. After the finding that the double-decker Pc lanthanoid complex shows single-molecule magnet (SMM) behavior, it has attracted a large attention. This is partly due to a rising interest for the ‘molecular spintronics’, in which the freedoms of spin and charge of an electron are applied to the quantum process of information. SMMs represent a class of compounds in which a single molecule behaves as a magnet. The reported blocking temperature, below which a single SMM molecule works as an quantum magnet, has been increasing with the development in the molecular design and synthesis techniques of multiple-decker Pc complex. However, even the bulk properties of these molecules are promising for the use of electronic materials, the films of multi-decker Pc molecules is less studied than those for the MPc molecules. An intriguing structural property is expected for the multi-decker Pc molecules since the Pc planes are linked by metal atoms. This gives an additional degree of freedom to the rotational angle between the two Pc ligands, and they can make a wheel-like symmetric rotation. Due to a simple and well-defined structure of a multi-decker Pc complex, the molecule can be a model molecule for molecular machine studies. The multi-decker Pc molecules can provide

  14. Adaptive, Small-Rotation-Based, Corotational Technique for Analysis of 2D Nonlinear Elastic Frames

    Directory of Open Access Journals (Sweden)

    Jaroon Rungamornrat

    2014-01-01

    Full Text Available This paper presents an efficient and accurate numerical technique for analysis of two-dimensional frames accounted for both geometric nonlinearity and nonlinear elastic material behavior. An adaptive remeshing scheme is utilized to optimally discretize a structure into a set of elements where the total displacement can be decomposed into the rigid body movement and one possessing small rotations. This, therefore, allows the force-deformation relationship for the latter part to be established based on small-rotation-based kinematics. Nonlinear elastic material model is integrated into such relation via the prescribed nonlinear moment-curvature relationship. The global force-displacement relation for each element can be derived subsequently using corotational formulations. A final system of nonlinear algebraic equations along with its associated gradient matrix for the whole structure is obtained by a standard assembly procedure and then solved numerically by Newton-Raphson algorithm. A selected set of results is then reported to demonstrate and discuss the computational performance including the accuracy and convergence of the proposed technique.

  15. Drift-Induced Enhancement of Cubic Dresselhaus Spin-Orbit Interaction in a Two-Dimensional Electron Gas

    Science.gov (United States)

    Kunihashi, Yoji; Sanada, Haruki; Tanaka, Yusuke; Gotoh, Hideki; Onomitsu, Koji; Nakagawara, Keita; Kohda, Makoto; Nitta, Junsaku; Sogawa, Tetsuomi

    2017-11-01

    We investigated the effect of an in-plane electric field on drifting spins in a GaAs quantum well. Kerr rotation images of the drifting spins revealed that the spin precession wavelength increases with increasing drift velocity regardless of the transport direction. A model developed for drifting spins with a heated electron distribution suggests that the in-plane electric field enhances the effective magnetic field component originating from the cubic Dresselhaus spin-orbit interaction.

  16. Nanofiber production of poly (vinylidene fluoride) / hexaferrite, obtained by Blow Spinning Technique

    International Nuclear Information System (INIS)

    Dias, G.C.; Zadorosny, L.; Malmonge, J.A.; Malmonge, L.F.

    2014-01-01

    In this study, fibrous films of poly (vinylidene fluoride) - PVDF with barium hexaferrite particles were obtained by Solution Blow Spinning technique. In such technique, the polymer solution is injected through an inner nozzle which experiences the action of an accelerated flux of gas that drags and stretches the jet solution forming the nanofibers. The films were obtained from solutions of PVDF/DMF (30% w/v), which was incorporated into barium hexaferrite particles in proportions of 1, 3 and 5% (w / w). The results of the micrographs revealed the formation of a fibrous film with good dispersion of the particles. Xray analyzes showed the predominance of the β crystalline phase of PVDF. The increase of the amount of particles induces the appearance of a characteristic peak of PVDF. EDX measurements confirmed the presence of particles in the films. (author)

  17. Moderately T2-weighted images obtained with the single-shot fast spin-echo technique. Differentiating between malignant and benign urinary obstructions

    International Nuclear Information System (INIS)

    Obuchi, Masao; Sugimoto, Hideharu; Kubota, Hayato; Yamamoto, Wakako; Kinebuchi, Yuko; Honda, Minoru; Takahara, Taro

    2002-01-01

    The purpose of this study was to determine whether a distinction could be made between benign and malignant urinary obstructions in moderately T 2 -weighted images obtained with the single-shot fast spin-echo technique. Forty-four lesions in 39 patients with urinary obstruction were evaluated with the single-shot fast spin-echo (SSFSE) technique with an effective TE of 90-100 ms and without fat saturation. Benign and malignant lesions were compared for the presence of ureteral wall thickening and a signal intensity relative to the proximal ureteral wall. Statistically significant differences were found between benign and malignant lesions in both morphologic change (P 2 -weighted SSFSE technique without fat saturation can accurately distinguish between benign and malignant urinary obstructions. (author)

  18. Single-spin stochastic optical reconstruction microscopy.

    Science.gov (United States)

    Pfender, Matthias; Aslam, Nabeel; Waldherr, Gerald; Neumann, Philipp; Wrachtrup, Jörg

    2014-10-14

    We experimentally demonstrate precision addressing of single-quantum emitters by combined optical microscopy and spin resonance techniques. To this end, we use nitrogen vacancy (NV) color centers in diamond confined within a few ten nanometers as individually resolvable quantum systems. By developing a stochastic optical reconstruction microscopy (STORM) technique for NV centers, we are able to simultaneously perform sub-diffraction-limit imaging and optically detected spin resonance (ODMR) measurements on NV spins. This allows the assignment of spin resonance spectra to individual NV center locations with nanometer-scale resolution and thus further improves spatial discrimination. For example, we resolved formerly indistinguishable emitters by their spectra. Furthermore, ODMR spectra contain metrology information allowing for sub-diffraction-limit sensing of, for instance, magnetic or electric fields with inherently parallel data acquisition. As an example, we have detected nuclear spins with nanometer-scale precision. Finally, we give prospects of how this technique can evolve into a fully parallel quantum sensor for nanometer resolution imaging of delocalized quantum correlations.

  19. Theoretical prediction of a rotating magnon wave packet in ferromagnets.

    Science.gov (United States)

    Matsumoto, Ryo; Murakami, Shuichi

    2011-05-13

    We theoretically show that the magnon wave packet has a rotational motion in two ways: a self-rotation and a motion along the boundary of the sample (edge current). They are similar to the cyclotron motion of electrons, but unlike electrons the magnons have no charge and the rotation is not due to the Lorentz force. These rotational motions are caused by the Berry phase in momentum space from the magnon band structure. Furthermore, the rotational motion of the magnon gives an additional correction term to the magnon Hall effect. We also discuss the Berry curvature effect in the classical limit of long-wavelength magnetostatic spin waves having macroscopic coherence length.

  20. Circuit quantum electrodynamics with a spin qubit.

    Science.gov (United States)

    Petersson, K D; McFaul, L W; Schroer, M D; Jung, M; Taylor, J M; Houck, A A; Petta, J R

    2012-10-18

    Electron spins trapped in quantum dots have been proposed as basic building blocks of a future quantum processor. Although fast, 180-picosecond, two-quantum-bit (two-qubit) operations can be realized using nearest-neighbour exchange coupling, a scalable, spin-based quantum computing architecture will almost certainly require long-range qubit interactions. Circuit quantum electrodynamics (cQED) allows spatially separated superconducting qubits to interact via a superconducting microwave cavity that acts as a 'quantum bus', making possible two-qubit entanglement and the implementation of simple quantum algorithms. Here we combine the cQED architecture with spin qubits by coupling an indium arsenide nanowire double quantum dot to a superconducting cavity. The architecture allows us to achieve a charge-cavity coupling rate of about 30 megahertz, consistent with coupling rates obtained in gallium arsenide quantum dots. Furthermore, the strong spin-orbit interaction of indium arsenide allows us to drive spin rotations electrically with a local gate electrode, and the charge-cavity interaction provides a measurement of the resulting spin dynamics. Our results demonstrate how the cQED architecture can be used as a sensitive probe of single-spin physics and that a spin-cavity coupling rate of about one megahertz is feasible, presenting the possibility of long-range spin coupling via superconducting microwave cavities.

  1. Study of the joining particle rotation in nuclei of 161-167 Er and 235 U

    International Nuclear Information System (INIS)

    Fernandez L, M.

    1996-01-01

    The residual quadrupole pairing and spin-spin interactions among the nucleons, in presence of the rotational motion, lead to additional terms in the particle-rotation coupling which attenuate the effects of the Coriolis interaction. These couplings are determined by using the density matrix formalism, under the consideration of the exact conservation of the nuclear angular moment. Finally the energy levels of the rotational bands and the mixing amplitudes of the BE2 transition probabilities are calculated for some odd deformed nuclei. A very good agreement between the theoretical and experimental energies is obtained. The Coriolis attenuation produced by these interactions shows itself as relevant for explaining the experimental results. (Author)

  2. Spinning strings in AdS3×S3 with NS–NS flux

    Directory of Open Access Journals (Sweden)

    Rafael Hernández

    2014-11-01

    Full Text Available The sigma model describing closed strings rotating in AdS3×S3 is known to reduce to the one-dimensional Neumann–Rosochatius integrable system. In this article we show that closed spinning strings in AdS3×S3×T4 in the presence of NS–NS three-form flux can be described by an extension of the Neumann–Rosochatius system. We consider closed strings rotating with one spin in AdS3 and two different angular momenta in S3. For a class of solutions with constant radii we find the dependence of the classical energy on the spin and the angular momenta as an expansion in the square of the 't Hooft coupling of the theory.

  3. Einstein-aether theory: dynamics of relativistic particles with spin or polarization in a Gödel-type universe

    Energy Technology Data Exchange (ETDEWEB)

    Balakin, Alexander B.; Popov, Vladimir A., E-mail: alexander.balakin@kpfu.ru, E-mail: vladipopov@mail.ru [Department of General Relativity and Gravitation, Institute of Physics, Kazan Federal University, Kremlevskaya str. 18, Kazan 420008 (Russian Federation)

    2017-04-01

    In the framework of the Einstein-aether theory we consider a cosmological model, which describes the evolution of the unit dynamic vector field with activated rotational degree of freedom. We discuss exact solutions of the Einstein-aether theory, for which the space-time is of the Gödel-type, the velocity four-vector of the aether motion is characterized by a non-vanishing vorticity, thus the rotational vectorial modes can be associated with the source of the universe rotation. The main goal of our paper is to study the motion of test relativistic particles with a vectorial internal degree of freedom (spin or polarization), which is coupled to the unit dynamic vector field. The particles are considered as the test ones in the given space-time background of the Gödel-type; the spin (polarization) coupling to the unit dynamic vector field is modeled using exact solutions of three types. The first exact solution describes the aether with arbitrary Jacobson's coupling constants; the second one relates to the case, when the Jacobson's constant responsible for the vorticity is vanishing; the third exact solution is obtained using three constraints for the coupling constants. The analysis of the exact expressions, which are obtained for the particle momentum and for the spin (polarization) four-vector components, shows that the interaction of the spin (polarization) with the unit vector field induces a rotation, which is additional to the geodesic precession of the spin (polarization) associated with the universe rotation as a whole.

  4. Spin dynamics in the anisotropic spin glass Fe2TiO5

    DEFF Research Database (Denmark)

    Yeshurun, Y.; Tholence, J. L.; Kjems, Jørgen

    1985-01-01

    We have studied spin-freezing phenomena along the magnetic easy axis of the insulating spin glass Fe2TiOS by magnetisation, AC susceptibility and neutron scattering experiments. The characteristic measurement time for these techniques varies over more than fourteen orders of magnitude. The results...

  5. Fast spin of the young extrasolar planet β Pictoris b.

    Science.gov (United States)

    Snellen, Ignas A G; Brandl, Bernhard R; de Kok, Remco J; Brogi, Matteo; Birkby, Jayne; Schwarz, Henriette

    2014-05-01

    The spin of a planet arises from the accretion of angular momentum during its formation, but the details of this process are still unclear. In the Solar System, the equatorial rotation velocities and, consequently, spin angular momenta of most of the planets increase with planetary mass; the exceptions to this trend are Mercury and Venus, which, since formation, have significantly spun down because of tidal interactions. Here we report near-infrared spectroscopic observations, at a resolving power of 100,000, of the young extrasolar gas giant planet β Pictoris b (refs 7, 8). The absorption signal from carbon monoxide in the planet's thermal spectrum is found to be blueshifted with respect to that from the parent star by approximately 15 kilometres per second, consistent with a circular orbit. The combined line profile exhibits a rotational broadening of about 25 kilometres per second, meaning that β Pictoris b spins significantly faster than any planet in the Solar System, in line with the extrapolation of the known trend in spin velocity with planet mass.

  6. MFM observation of spin structures in nano-magnetic-dot arrays fabricated by damascene technique

    International Nuclear Information System (INIS)

    Sato, K.; Yamamoto, T.; Tezuka, T.; Ishibashi, T.; Morishita, Y.; Koukitu, A.; Machida, K.; Yamaoka, T.

    2006-01-01

    Regularly aligned arrays of magnetic nano dots buried in silicon wafers have been fabricated using damascene technique with the help of electron beam lithography. Arrays of square, rectangular, cross-shaped and Y-shaped structures of submicron size have been obtained. Spin distributions have been observed by means of magnetic force microscopy and analyzed by a micromagnetic simulation with Landau-Lifshitz-Gilbert equations. Importance of magnetostatic interactions working between adjacent dots has been elucidated

  7. Quantum computation in semiconductor quantum dots of electron-spin asymmetric anisotropic exchange

    International Nuclear Information System (INIS)

    Hao Xiang; Zhu Shiqun

    2007-01-01

    The universal quantum computation is obtained when there exists asymmetric anisotropic exchange between electron spins in coupled semiconductor quantum dots. The asymmetric Heisenberg model can be transformed into the isotropic model through the control of two local unitary rotations for the realization of essential quantum gates. The rotations on each qubit are symmetrical and depend on the strength and orientation of asymmetric exchange. The implementation of the axially symmetric local magnetic fields can assist the construction of quantum logic gates in anisotropic coupled quantum dots. This proposal can efficiently use each physical electron spin as a logical qubit in the universal quantum computation

  8. Data structure techniques for the graphical special unitary group approach to arbitrary spin representations

    International Nuclear Information System (INIS)

    Kent, R.D.; Schlesinger, M.

    1987-01-01

    For the purpose of computing matrix elements of quantum mechanical operators in complex N-particle systems it is necessary that as much of each irreducible representation be stored in high-speed memory as possible in order to achieve the highest possible rate of computations. A graph theoretic approach to the representation of N-particle systems involving arbitrary single-particle spin is presented. The method involves a generalization of a technique employed by Shavitt in developing the graphical group approach (GUGA) to electronic spin-orbitals. The methods implemented in GENDRT and DRTDIM overcome many deficiencies inherent in other approaches, particularly with respect to utilization of memory resources, computational efficiency in the recognition and evaluation of non-zero matrix elements of certain group theoretic operators and complete labelling of all the basis states of the permutation symmetry (S N ) adapted irreducible representations of SU(n) groups. (orig.)

  9. The Influence of Stellar Spin on Ignition of Thermonuclear Runaways

    Science.gov (United States)

    Galloway, Duncan K.; in ’t Zand, Jean J. M.; Chenevez, Jérôme; Keek, Laurens; Sanchez-Fernandez, Celia; Worpel, Hauke; Lampe, Nathanael; Kuulkers, Erik; Watts, Anna; Ootes, Laura; The MINBAR collaboration

    2018-04-01

    Runaway thermonuclear burning of a layer of accumulated fuel on the surface of a compact star provides a brief but intense display of stellar nuclear processes. For neutron stars accreting from a binary companion, these events manifest as thermonuclear (type-I) X-ray bursts, and recur on typical timescales of hours to days. We measured the burst rate as a function of accretion rate, from seven neutron stars with known spin rates, using a burst sample accumulated over several decades. At the highest accretion rates, the burst rate is lower for faster spinning stars. The observations imply that fast (>400 Hz) rotation encourages stabilization of nuclear burning, suggesting a dynamical dependence of nuclear ignition on the spin rate. This dependence is unexpected, because faster rotation entails less shear between the surrounding accretion disk and the star. Large-scale circulation in the fuel layer, leading to enhanced mixing of the burst ashes into the fuel layer, may explain this behavior; further numerical simulations are required to confirm this.

  10. Systematic construction of spin liquids on the square lattice from tensor networks with SU(2) symmetry

    Science.gov (United States)

    Mambrini, Matthieu; Orús, Román; Poilblanc, Didier

    2016-11-01

    We elaborate a simple classification scheme of all rank-5 SU(2) spin rotational symmetric tensors according to (i) the onsite physical spin S , (ii) the local Hilbert space V⊗4 of the four virtual (composite) spins attached to each site, and (iii) the irreducible representations of the C4 v point group of the square lattice. We apply our scheme to draw a complete list of all SU(2)-symmetric translationally and rotationally invariant projected entangled pair states (PEPS) with bond dimension D ≤6 . All known SU(2)-symmetric PEPS on the square lattice are recovered and simple generalizations are provided in some cases. More generally, to each of our symmetry class can be associated a (D -1 )-dimensional manifold of spin liquids (potentially) preserving lattice symmetries and defined in terms of D -independent tensors of a given bond dimension D . In addition, generic (low-dimensional) families of PEPS explicitly breaking either (i) particular point-group lattice symmetries (lattice nematics) or (ii) time-reversal symmetry (chiral spin liquids) or (iii) SU(2) spin rotation symmetry down to U(1 ) (spin nematics or Néel antiferromagnets) can also be constructed. We apply this framework to search for new topological chiral spin liquids characterized by well-defined chiral edge modes, as revealed by their entanglement spectrum. In particular, we show how the symmetrization of a double-layer PEPS leads to a chiral topological state with a gapless edge described by a SU (2) 2 Wess-Zumino-Witten model.

  11. Nuclear spin-lattice relaxation in carbon nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Panich, A.M., E-mail: pan@bgu.ac.i [Department of Physics, Ben-Gurion University of the Negev, P.O. Box 653, Beer Sheva 84105 (Israel); Sergeev, N.A. [Institute of Physics, University of Szczecin, 70-451 Szczecin (Poland)

    2010-04-15

    Interpretation of nuclear spin-lattice relaxation data in the carbon nanostructures is usually based on the analysis of fluctuations of dipole-dipole interactions of nuclear spins and anisotropic electron-nuclear interactions responsible for chemical shielding, which are caused by molecular dynamics. However, many nanocarbon systems such as fullerene and nanotube derivatives, nanodiamonds and carbon onions reveal noticeable amount of paramagnetic defects with unpaired electrons originating from dangling bonds. The interaction between nuclear and electron spins strongly influences the nuclear spin-lattice relaxation, but usually is not taken into account, thus the relaxation data are not correctly interpreted. Here we report on the temperature dependent NMR spectra and spin-lattice relaxation measurements of intercalated fullerenes C{sub 60}(MF{sub 6}){sub 2} (M=As and Sb), where nuclear relaxation is caused by both molecular rotation and interaction between nuclei and unpaired electron spins. We present a detailed theoretical analysis of the spin-lattice relaxation data taking into account both these contributions. Good agreement between the experimental data and calculations is obtained. The developed approach would be useful in interpreting the NMR relaxation data in different nanostructures and their intercalation compounds.

  12. Theoretical studies on nuclear spin selective quantum dynamics of non-linear molecules; Theoretische Untersuchung zur Quantendynamik der Kernspinisomere nicht-linearer Molekuele

    Energy Technology Data Exchange (ETDEWEB)

    Grohmann, Thomas

    2012-05-31

    In this thesis the wave packet dynamics of nuclear spin isomers of polyatomic molecules after interaction with static and time-dependent magnetic fields and moderate intense nonresonant laser pulses is investigated. In particular, the process of inducing (internal) molecular rotation as well as alignment of molecules by manipulating their rotational or rotational-torsional degrees of freedom is studied. In the first part of the thesis all theoretical concepts for identifying nuclear spin isomers and for describing their quantum dynamics will be discussed. Especially the symmetrization postulate and themolecular symmetry group will be introduced and illustrated for some examples of molecules. These concepts will be extended to the case of identifying nuclear spin isomers in the presence of an external field. In the second part it is shown for nitromethane that magnetic fields are able to induce unidirectional rotations in opposite directions for different nuclear spin isomers of molecules containing methyl groups if the dipolar interaction is included. Additionally, it is demonstrated that different nuclear spin isomers of a chemical compound may show different alignment after the interaction with a moderate intense laser pulse. As shown for the rigid symmetric top propadien and the rigid asymmetric tops ethene and analogues, distinct pairs of nuclear spin isomers show at certain points in time a complementary behavior: while one isomer is showing alignment the partner isomer is showing anti-alignment. Moreover, it is illustrated that not every nuclear spin isomer can be aligned equally efficient. The alignment of non-rigid molecules is considered as well. As an example for a molecule with feasible torsion in the electronic ground state, the alignment of diboron tetrafluoride is investigated. It becomes apparent that not only rotational but also the torsional dynamics of the molecules is nuclear spin selective; different nuclear spin isomers have at distinct points

  13. Spin-wave propagation and spin-polarized electron transport in single-crystal iron films

    Science.gov (United States)

    Gladii, O.; Halley, D.; Henry, Y.; Bailleul, M.

    2017-11-01

    The techniques of propagating spin-wave spectroscopy and current-induced spin-wave Doppler shift are applied to a 20-nm-thick Fe/MgO(001) film. The magnetic parameters extracted from the position of the spin-wave resonance peaks are very close to those tabulated for bulk iron. From the zero-current propagating wave forms, a group velocity of 4 km/s and an attenuation length of about 6 μ m are extracted for 1.6-μ m -wavelength spin wave at 18 GHz. From the measured current-induced spin-wave Doppler shift, we extract a surprisingly high degree of spin polarization of the current of 83 % , which constitutes the main finding of this work. This set of results makes single-crystalline iron a promising candidate for building devices utilizing high-frequency spin waves and spin-polarized currents.

  14. Research on the development of the centrifugal spinning

    Directory of Open Access Journals (Sweden)

    Zhang Zhiming

    2017-01-01

    Full Text Available Centrifugal spinning is a new and efficient method to produce nanofibers quickly. It makes use of the centrifugal force instead of high voltage to produce the nanofibers. The centrifugal spinning has many advantages such as no high voltage, high yield, simple structure, no pollution and can be applied to high polymer material, ceramic and metal material. In order to have more understand about this novel nanofibers formation method, this paper introduces the method of centrifugal spinning and the effect of rotation speed, the properties of material such as viscosity and solvent evaporation, collector distance which have an impact on nanofibers morphology and diameter were also analyzed.

  15. A scanning tunneling microscopy based potentiometry technique and its application to the local sensing of the spin Hall effect

    Directory of Open Access Journals (Sweden)

    Ting Xie

    2017-12-01

    Full Text Available A scanning tunneling microscopy based potentiometry technique for the measurements of the local surface electric potential is presented. A voltage compensation circuit based on this potentiometry technique is developed and employed to maintain a desired tunneling voltage independent of the bias current flow through the film. The application of this potentiometry technique to the local sensing of the spin Hall effect is outlined and some experimental results are reported.

  16. Effect of shoulder abduction angle on biomechanical properties of the repaired rotator cuff tendons with 3 types of double-row technique.

    Science.gov (United States)

    Mihata, Teruhisa; Fukuhara, Tetsutaro; Jun, Bong Jae; Watanabe, Chisato; Kinoshita, Mitsuo

    2011-03-01

    After rotator cuff repair, the shoulder is immobilized in various abduction positions. However, there is no consensus on the proper abduction angle. To assess the effect of shoulder abduction angle on the biomechanical properties of the repaired rotator cuff tendons among 3 types of double-row techniques. Controlled laboratory study. Thirty-two fresh-frozen porcine shoulders were used. A simulated rotator cuff tear was repaired by 1 of 3 double-row techniques: conventional double-row repair, transosseous-equivalent repair, and a combination of conventional double-row and bridging sutures (compression double-row repair). Each specimen underwent cyclic testing followed by tensile testing to failure at a simulated shoulder abduction angle of 0° or 40° on a material testing machine. Gap formation and failure loads were measured. Gap formation in conventional double-row repair at 0° (1.2 ± 0.5 mm) was significantly greater than that at 40° (0.5 ± 0.3mm, P = .01). The yield and ultimate failure loads for conventional double-row repair at 40° were significantly larger than those at 0° (P row repair (P row repair was the greatest among the 3 double-row techniques at both 0° and 40° of abduction. Bridging sutures have a greater effect on the biomechanical properties of the repaired rotator cuff tendon at a low abduction angle, and the conventional double-row technique has a greater effect at a high abduction angle. Proper abduction position after rotator cuff repair differs between conventional double-row repair and transosseous-equivalent repair. The authors recommend the use of the combined technique of conventional double-row and bridging sutures to obtain better biomechanical properties at both low and high abduction angles.

  17. Electronic changes induced by μ+ in PrIn3: Muon-spin-rotation observation and crystalline-electric-field model calculation

    International Nuclear Information System (INIS)

    Tashma, T.; Amato, A.; Grayevsky, A.; Gygax, F.N.; Pinkpank, M.; Schenck, A.; Kaplan, N.

    1997-01-01

    Muon spin rotation in a single crystal of PrIn 3 reveals a significant influence of the implanted μ + on the local susceptibility χ 1 of the neighboring Pr +3 ions below ∼60K. It is found that χ 1 differs from χ bulk both in magnitude and in symmetry. All of the changes are accounted for by a model calculation based on crystalline-electric-field theory. The extent of the μ + -induced magnetic changes in the present system of PrIn 3 is rather modest compared to previously reported induced changes in PrNi 5 . However, the model-derived electronic-structure changes around the μ + in PrIn 3 appear remarkably similar to those in PrNi 5 , as is to be expected if the driving perturbation in both systems is primarily Coulombic in nature. copyright 1997 The American Physical Society

  18. The first muon spin rotation experiment

    CERN Document Server

    Garwin, Richard L

    2003-01-01

    The February 15, 1957 issue of Physical Review Letters shows the first muon precession curve resulting from the stopping of `85 MeV' muons in graphite, and the resulting counting rate in a gate of fixed delay, duration, and orientation, as a function of an applied vertical magnetic field. The purpose of the four-day experiment was to test the conservation of parity in the weak interactions. It involved the sudden recognition that existing muon beams would be polarized if parity were not conserved, together with the appreciation that the angular distribution of decay electrons from the population of stopped muons could be observed (much more reliably and sensitively) by the variation with time or current of the detections in a fixed counter telescope than by the measurement of the decay asymmetry of nominally fixed muon spins. This retrospective paper explains the context, the state of the art at the time, and what we expected as a consequence of this experiment. We went on to study more accurately the magneti...

  19. Preservation of bursal-sided tendon in partial-thickness articular-sided rotator cuff tears: a novel arthroscopic transtendon anatomic repair technique.

    Science.gov (United States)

    Shin, Sang-Jin; Jeong, Jae-Hoon; Jeon, Yoon Sang; Kim, Rag Gyu

    2016-12-01

    The purpose of this study was to introduce a novel arthroscopic transtendon anatomic repair technique that spares the intact bursal-sided tendon in articular-sided partial-thickness rotator cuff tears (PTRCT) and to present shoulder functional outcomes in patients with symptomatic articular-sided PCRCT that involves more than 50 % of its thickness after arthroscopic repair using a novel technique. Eighteen patients with symptomatic articular-sided PCRCT involving more than 50 % of the tendon's thickness underwent arthroscopic repair using a devised technique. The devised technique restores only the torn articular portion of the rotator cuff at the anatomical footprint using a suture anchor, and preserves the integrity of the corresponding bursal-sided tendon by tying knots at the most lateral bursal side on the subacromial space. Clinical and functional outcome using ASES and Constant scores were evaluated. The structural integrity of the rotator cuff was evaluated by MRI at 6 months postoperatively. Pain relief and shoulder functional outcomes were encouraging during the recovery phase after operation. ASES (preoperative 54.0 ± 10.3 to postoperative 92.6 ± 8.0), Constant score (61.2 ± 8.5-88.0 ± 5.3), VAS for pain (4.9 ± 2.6-0.6 ± 0.7) improved significantly after arthroscopic transtendon anatomic repair (p rotator cuff retears on 6-month MRI. No complications related to surgical procedures had occurred. The devised technique of arthroscopic transtendon repair provided satisfactory functional outcomes without postoperative discomforts. This technique minimizes over-tightening of the articular layer and reduces tension mismatches between the articular and bursal layers, which are considered as important factors for improvement of postoperative shoulder motion.

  20. Investigation of the field dependent spin structure of exchange coupled magnetic heterostructures

    International Nuclear Information System (INIS)

    Gurieva, Tatiana

    2016-05-01

    This thesis describes the investigation of the field dependent magnetic spin structure of an antiferromagnetically (AF) coupled Fe/Cr heterostructure sandwiched between a hardmagnetic FePt buffer layer and a softmagnetic Fe top layer. The depth-resolved experimental studies of this system were performed via Magneto-optical Kerr effect (MOKE), Vibrating Sample Magnetometry (VSM) and various measuring methods based on nuclear resonant scattering (NRS) technique. Nucleation and evolution of the magnetic spiral structure in the AF coupled Fe/Cr multilayer structure in an azimuthally rotating external magnetic field were observed using NRS. During the experiment a number of time-dependent magnetic side effects (magnetic after-effect, domain-wall creep effect) caused by the non-ideal structure of a real sample were observed and later explained. Creation of the magnetic spiral structure in rotating external magnetic field was simulated using a one-dimensional micromagnetic model.The cross-sectional magnetic X-ray diffraction technique was conceived and is theoretically described in the present work. This method allows to determine the magnetization state of an individual layer in the magnetic heterostructure. It is also applicable in studies of the magnetic structure of tiny samples where conventional x-ray reflectometry fails.

  1. Thermoelectric effects and spin injection into superconductors with exchange field

    Energy Technology Data Exchange (ETDEWEB)

    Heikkilae, Tero [Dept. Phys., Univ. Jyvaeskylae (Finland); Silaev, Mihail [O.V. Lounasmaa Lab, Aalto Univ. (Finland); Dept. Theor. Physics, KTH, Stockholm (Sweden); Virtanen, Pauli [O.V. Lounasmaa Lab, Aalto Univ. (Finland); Giazotto, Francesco [NEST CNR-INFM and SNS Pisa (Italy); Ozaeta, Asier; Bergeret, Sebastian [CFM-CSIC and DIPC, San Sebastian (Spain)

    2015-07-01

    When a thin superconducting film is exposed to a longitudinal magnetic field or is in proximity to a ferromagnet, an exchange field separating the spin bands emerges in it. For low enough exchange fields superconductivity survives, but its response to external driving is strongly modified. In my talk I will show how at linear response such systems exhibit very strong thermoelectric response with an almost ideal efficiency. For strong driving, this effect creates a spin accumulation that can only relax via thermalization, and therefore at low temperatures has a very long range. Therefore our work explains recent observations of the long-range spin accumulation in spin-split superconductors. When injecting spin from injectors with non-collinear magnetization compared to the exchange field, the spins start to rotate around the latter. I will describe how superconductivity modifies this spin Hanle effect so that the resulting nonlocal magnetoresistance depends on the details of spin relaxation, therefore allowing for probing them.

  2. Asteroid collisional history - Effects on sizes and spins

    International Nuclear Information System (INIS)

    Davis, D.R.; Weidenschilling, S.J.; Farinella, P.; Paolicchi, P.; Binzel, R.P.

    1989-01-01

    The effects of asteroid collisional history on sizes and spins of present-day objects are discussed. Collisional evolution studies indicate that collisions have altered the spin-rates of small bodies, but that the largest asteroids may have retained their primordial rotation rates. Most asteroids larger than 100 km diam have probably been shattered, but have gravitationally recaptured their fragments to form a rubble-pile structure. Large angular momentum asteroids appear to have Maclaurian spheroidal or Jacobi-ellipsoid-like shapes; some of them may have fissioned into binaries. An integrated size and spin collisional evolution model is presented, with two critical parameters: one which determines the spin rates for small fragments resulting from a shattering collision, and the other determines the fraction of impact angular momentum that is retained by the target. 36 refs

  3. EFFECTS OF SPIN ON HIGH-ENERGY RADIATION FROM ACCRETING BLACK HOLES

    Energy Technology Data Exchange (ETDEWEB)

    O’ Riordan, Michael; Pe’er, Asaf [Physics Department, University College Cork, Cork (Ireland); McKinney, Jonathan C., E-mail: michael_oriordan@umail.ucc.ie [Department of Physics and Joint Space-Science Institute, University of Maryland, College Park, MD 20742 (United States)

    2016-11-01

    Observations of jets in X-ray binaries show a correlation between radio power and black hole spin. This correlation, if confirmed, points toward the idea that relativistic jets may be powered by the rotational energy of black holes. In order to examine this further, we perform general relativistic radiative transport calculations on magnetically arrested accretion flows, which are known to produce powerful jets via the Blandford–Znajek (BZ) mechanism. We find that the X-ray and γ -ray emission strongly depend on spin and inclination angle. Surprisingly, the high-energy power does not show the same dependence on spin as the BZ jet power, but instead can be understood as a redshift effect. In particular, photons observed perpendicular to the spin axis suffer little net redshift until originating from close to the horizon. Such observers see deeper into the hot, dense, highly magnetized inner disk region. This effect is largest for rapidly rotating black holes due to a combination of frame dragging and decreasing horizon radius. While the X-ray emission is dominated by the near horizon region, the near-infrared (NIR) radiation originates at larger radii. Therefore, the ratio of X-ray to NIR power is an observational signature of black hole spin.

  4. Perturbation of nuclear spin polarizations in solid state NMR of nitroxide-doped samples by magic-angle spinning without microwaves

    Energy Technology Data Exchange (ETDEWEB)

    Thurber, Kent R., E-mail: thurberk@niddk.nih.gov; Tycko, Robert [Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520 (United States)

    2014-05-14

    We report solid state {sup 13}C and {sup 1}H nuclear magnetic resonance (NMR) experiments with magic-angle spinning (MAS) on frozen solutions containing nitroxide-based paramagnetic dopants that indicate significant perturbations of nuclear spin polarizations without microwave irradiation. At temperatures near 25 K, {sup 1}H and cross-polarized {sup 13}C NMR signals from {sup 15}N,{sup 13}C-labeled L-alanine in trinitroxide-doped glycerol/water are reduced by factors as large as six compared to signals from samples without nitroxide doping. Without MAS or at temperatures near 100 K, differences between signals with and without nitroxide doping are much smaller. We attribute most of the reduction of NMR signals under MAS near 25 K to nuclear spin depolarization through the cross-effect dynamic nuclear polarization mechanism, in which three-spin flips drive nuclear polarizations toward equilibrium with spin polarization differences between electron pairs. When T{sub 1e} is sufficiently long relative to the MAS rotation period, the distribution of electron spin polarization across the nitroxide electron paramagnetic resonance lineshape can be very different from the corresponding distribution in a static sample at thermal equilibrium, leading to the observed effects. We describe three-spin and 3000-spin calculations that qualitatively reproduce the experimental observations.

  5. Perturbation of nuclear spin polarizations in solid state NMR of nitroxide-doped samples by magic-angle spinning without microwaves

    International Nuclear Information System (INIS)

    Thurber, Kent R.; Tycko, Robert

    2014-01-01

    We report solid state 13 C and 1 H nuclear magnetic resonance (NMR) experiments with magic-angle spinning (MAS) on frozen solutions containing nitroxide-based paramagnetic dopants that indicate significant perturbations of nuclear spin polarizations without microwave irradiation. At temperatures near 25 K, 1 H and cross-polarized 13 C NMR signals from 15 N, 13 C-labeled L-alanine in trinitroxide-doped glycerol/water are reduced by factors as large as six compared to signals from samples without nitroxide doping. Without MAS or at temperatures near 100 K, differences between signals with and without nitroxide doping are much smaller. We attribute most of the reduction of NMR signals under MAS near 25 K to nuclear spin depolarization through the cross-effect dynamic nuclear polarization mechanism, in which three-spin flips drive nuclear polarizations toward equilibrium with spin polarization differences between electron pairs. When T 1e is sufficiently long relative to the MAS rotation period, the distribution of electron spin polarization across the nitroxide electron paramagnetic resonance lineshape can be very different from the corresponding distribution in a static sample at thermal equilibrium, leading to the observed effects. We describe three-spin and 3000-spin calculations that qualitatively reproduce the experimental observations

  6. Perturbation of nuclear spin polarizations in solid state NMR of nitroxide-doped samples by magic-angle spinning without microwaves.

    Science.gov (United States)

    Thurber, Kent R; Tycko, Robert

    2014-05-14

    We report solid state (13)C and (1)H nuclear magnetic resonance (NMR) experiments with magic-angle spinning (MAS) on frozen solutions containing nitroxide-based paramagnetic dopants that indicate significant perturbations of nuclear spin polarizations without microwave irradiation. At temperatures near 25 K, (1)H and cross-polarized (13)C NMR signals from (15)N,(13)C-labeled L-alanine in trinitroxide-doped glycerol/water are reduced by factors as large as six compared to signals from samples without nitroxide doping. Without MAS or at temperatures near 100 K, differences between signals with and without nitroxide doping are much smaller. We attribute most of the reduction of NMR signals under MAS near 25 K to nuclear spin depolarization through the cross-effect dynamic nuclear polarization mechanism, in which three-spin flips drive nuclear polarizations toward equilibrium with spin polarization differences between electron pairs. When T1e is sufficiently long relative to the MAS rotation period, the distribution of electron spin polarization across the nitroxide electron paramagnetic resonance lineshape can be very different from the corresponding distribution in a static sample at thermal equilibrium, leading to the observed effects. We describe three-spin and 3000-spin calculations that qualitatively reproduce the experimental observations.

  7. Protostellar formation in rotation interstellar clouds. III. Nonaxisymmetric collapse

    International Nuclear Information System (INIS)

    Boss, A.P.

    1980-01-01

    A full three spatial-dimension gravitational hydrodynamics code has been used to follow the collapse of isothermal rotating clouds subjected to various nonaxialy symmetric perturbations (NAP). An initially axially symmetric cloud collapsed to form a ring which then fragmented into a binary protostellar system. A low thermal energy cloud with a large bar-shaped NAP collapsed and fragmented directly into a binary; higher thermal energy clouds damp out such NAPs while higher rotational rotational energy clouds produce binaries with wider separations. Fragmentation into single and binary systems has been seen. The tidal effects of other nearby protostellar clouds are shown to have an important effect upon the collapse and should not be neglected. The three-dimensional calculations indicate that isothermal interstellar clouds may fragment (with or without passing through a transitory ring phase) into protostellar objects while still in the isothermal regime. The fragments obtained have masses and specific spin angular momenta roughly a 10th that of the original cloud. Interstellar clouds and their fragments may pass through successive collapse phases with fragmentation and reduction of spin angular momentum (by conversion to orbital angular momentum and preferential accretion of low angular momentum matter) terminating in the formation of pre--main-sequence stars with the observed pre--main-sequence rotation rates

  8. Shell structure in superdeformed nuclei at high rotational frequencies

    International Nuclear Information System (INIS)

    Ploszajczak, M.

    1980-01-01

    Properties of the shell structure in superdeformed nuclei at high rotational frequencies are discussed. Moreover, stability of the high spin compound nucleus with respect to the fission and the emission of light particles is investigated. (author)

  9. Spin-spin cross relaxation and spin-Hamiltonian spectroscopy by optical pumping of Pr/sup 3+/:LaF3

    International Nuclear Information System (INIS)

    Lukac, M.; Otto, F.W.; Hahn, E.L.

    1989-01-01

    We report the observation of an anticrossing in solid-state laser spectroscopy produced by cross relaxation. Spin-spin cross relaxation between the /sup 141/Pr- and /sup 19/F-spin reservoirs in Pr/sup 3+/:LaF 3 and its influence on the /sup 141/Pr NMR spectrum is detected by means of optical pumping. The technique employed combines optical pumping and hole burning with either external magnetic field sweep or rf resonance saturation in order to produce slow transient changes in resonant laser transmission. At a certain value of the external Zeeman field, where the energy-level splittings of Pr and F spins match, a level repulsion and discontinuity of the Pr/sup 3+/ NMR lines is observed. This effect is interpreted as the ''anticrossing'' of the combined Pr-F spin-spin reservoir energy states. The Zeeman-quadrupole-Hamiltonian spectrum of the hyperfine optical ground states of Pr/sup 3+/:LaF 3 is mapped out over a wide range of Zeeman magnetic fields. A new scheme is proposed for dynamic polarization of nuclei by means of optical pumping, based on resonant cross relaxation between rare spins and spin reservoirs

  10. Reconstructing 1/2 BPS space-time metrics from matrix models and spin chains

    International Nuclear Information System (INIS)

    Vazquez, Samuel E.

    2007-01-01

    Using the anti-de Sitter/conformal field theories (AdS/CFT) correspondence, we address the question of how to measure complicated space-time metrics using gauge theory probes. In particular, we consider the case of the 1/2 Bogomol'nyi-Prasad-Sommerfield geometries of type IIB supergravity. These geometries are classified by certain droplets in a two-dimensional spacelike hypersurface. We show how to reconstruct the full metric inside these droplets using the one-loop N=4 super Yang-Mills theory dilatation operator. This is done by considering long operators in the SU(2) sector, which are dual to fast rotating strings on the droplets. We develop new powerful techniques for large N complex matrix models that allow us to construct the Hamiltonian for these strings. We find that the Hamiltonian can be mapped to a dynamical spin chain. That is, the length of the chain is not fixed. Moreover, all of these spin chains can be explicitly constructed using an interesting algebra which is derived from the matrix model. Our techniques work for general droplet configurations. As an example, we study a single elliptical droplet and the hypotrochoid

  11. Rapidly rotating pulsar radiation in vacuum nonlinear electrodynamics

    Energy Technology Data Exchange (ETDEWEB)

    Denisov, V.I.; Pimenov, A.B.; Sokolov, V.A. [Moscow State University, Physics Department, Moscow (Russian Federation); Denisova, I.P. [Moscow Aviation Institute (National Research University), Moscow (Russian Federation)

    2016-11-15

    In this paper we investigate the corrections of vacuum nonlinear electrodynamics on rapidly rotating pulsar radiation and spin-down in the perturbative QED approach (post-Maxwellian approximation). An analytical expression for the pulsar's radiation intensity has been obtained and analyzed. (orig.)

  12. Spinning Up Interest: Classroom Demonstrations of Rotating Fluid Dynamics

    Science.gov (United States)

    Aurnou, J.

    2005-12-01

    The complex relationship between rotation and its effect on fluid motions presents some of the most difficult and vexing concepts for both undergraduate and graduate level students to learn. We have found that student comprehension is greatly increased by the presentation of in-class fluid mechanics experiments. A relatively inexpensive experimental set-up consists of the following components: a record player, a wireless camera placed in the rotating frame, a tank of fluid, and food coloring. At my poster, I will use this set-up to carry out demonstrations that illustrate the Taylor-Proudman theorem, flow within the Ekman layer, columnar convection, and flow around high and low pressure centers. By sending the output of the wireless camera through an LCD projection system, such demonstrations can be carried out even for classes in large lecture halls.

  13. Does double-row rotator cuff repair improve functional outcome of patients compared with single-row technique? A systematic review.

    Science.gov (United States)

    DeHaan, Alexander M; Axelrad, Thomas W; Kaye, Elizabeth; Silvestri, Lorenzo; Puskas, Brian; Foster, Timothy E

    2012-05-01

    The advantage of single-row versus double-row arthroscopic rotator cuff repair techniques has been a controversial issue in sports medicine and shoulder surgery. There is biomechanical evidence that double-row techniques are superior to single-row techniques; however, there is no clinical evidence that the double-row technique provides an improved functional outcome. When compared with single-row rotator cuff repair, double-row fixation, although biomechanically superior, has no clinical benefit with respect to retear rate or improved functional outcome. Systematic review. The authors reviewed prospective studies of level I or II clinical evidence that compared the efficacy of single- and double-row rotator cuff repairs. Functional outcome scores included the American Shoulder and Elbow Surgeons (ASES) shoulder scale, the Constant shoulder score, and the University of California, Los Angeles (UCLA) shoulder rating scale. Radiographic failures and complications were also analyzed. A test of heterogeneity for patient demographics was also performed to determine if there were differences in the patient profiles across the included studies. Seven studies fulfilled our inclusion criteria. The test of heterogeneity across these studies showed no differences. The functional ASES, Constant, and UCLA outcome scores revealed no difference between single- and double-row rotator cuff repairs. The total retear rate, which included both complete and partial retears, was 43.1% for the single-row repair and 27.2% for the double-row repair (P = .057), representing a trend toward higher failures in the single-row group. Through a comprehensive literature search and meta-analysis of current arthroscopic rotator cuff repairs, we found that the single-row repairs did not differ from the double-row repairs in functional outcome scores. The double-row repairs revealed a trend toward a lower radiographic proven retear rate, although the data did not reach statistical significance. There

  14. M-dwarf rapid rotators and the detection of relatively young multiple M-star systems

    International Nuclear Information System (INIS)

    Rappaport, S.; Joss, M.; Sanchis-Ojeda, R.

    2014-01-01

    We have searched the Kepler light curves of ∼3900 M-star targets for evidence of periodicities that indicate, by means of the effects of starspots, rapid stellar rotation. Several analysis techniques, including Fourier transforms, inspection of folded light curves, 'sonograms', and phase tracking of individual modulation cycles, were applied in order to distinguish the periodicities due to rapid rotation from those due to stellar pulsations, eclipsing binaries, or transiting planets. We find 178 Kepler M-star targets with rotation periods, P rot , of <2 days, and 110 with P rot < 1 day. Some 30 of the 178 systems exhibit two or more independent short periods within the same Kepler photometric aperture, while several have 3 or more short periods. Adaptive optics imaging and modeling of the Kepler pixel response function for a subset of our sample support the conclusion that the targets with multiple periods are highly likely to be relatively young physical binary, triple, and even quadruple M star systems. We explore in detail the one object with four incommensurate periods all less than 1.2 days, and show that two of the periods arise from one of a close pair of stars, while the other two arise from the second star, which itself is probably a visual binary. If most of these M-star systems with multiple periods turn out to be bound M stars, this could prove a valuable way discovering young hierarchical M-star systems; the same approach may also be applicable to G and K stars. The ∼5% occurrence rate of rapid rotation among the ∼3900 M star targets is consistent with spin evolution models that include an initial contraction phase followed by magnetic braking, wherein a typical M star can spend several hundred Myr before spinning down to periods longer than 2 days.

  15. 3-D collapse of rotating stars to Kerr black holes

    International Nuclear Information System (INIS)

    Baiotti, L; Hawke, I; Montero, P J; Loeffler, F L; Rezzolla, L; Stergioulas, N; Font, J A; Seidel, E

    2005-01-01

    We study gravitational collapse of uniformly rotating neutron stars to Kerr black holes, using a new three-dimensional, fully general relativistic hydrodynamics code, which uses high-resolution shock-capturing techniques and a conformal traceless formulation of the Einstein equations. We investigate the gravitational collapse by carefully studying not only the dynamics of the matter, but also that of the trapped surfaces, i.e. of both the apparent and event horizons formed during the collapse. The use of these surfaces, together with the dynamical horizon framework, allows for a precise measurement of the black-hole mass and spin. The ability to successfully perform these simulations for sufficiently long times relies on excising a region of the computational domain which includes the singularity and is within the apparent horizon. The dynamics of the collapsing matter is strongly influenced by the initial amount of angular momentum in the progenitor star and, for initial models with sufficiently high angular velocities, the collapse can lead to the formation of an unstable disc in differential rotation

  16. Spin chains and string theory.

    Science.gov (United States)

    Kruczenski, Martin

    2004-10-15

    Recently, an important test of the anti de Sitter/conformal field theory correspondence has been done using rotating strings with two angular momenta. We show that such a test can be described more generally as the agreement between two actions: one a low energy description of a spin chain appearing in the field theory side, and the other a limit of the string action in AdS5xS5. This gives a map between the mean value of the spin in the boundary theory and the position of the string in the bulk, and shows how a string action can emerge from a gauge theory in the large-N limit.

  17. You Spin my Head Right Round: Threshold of Limited Immersion for Rotation Gains in Redirected Walking.

    Science.gov (United States)

    Schmitz, Patric; Hildebrandt, Julian; Valdez, Andre Calero; Kobbelt, Leif; Ziefle, Martina

    2018-04-01

    In virtual environments, the space that can be explored by real walking is limited by the size of the tracked area. To enable unimpeded walking through large virtual spaces in small real-world surroundings, redirection techniques are used. These unnoticeably manipulate the user's virtual walking trajectory. It is important to know how strongly such techniques can be applied without the user noticing the manipulation-or getting cybersick. Previously, this was estimated by measuring a detection threshold (DT) in highly-controlled psychophysical studies, which experimentally isolate the effect but do not aim for perceived immersion in the context of VR applications. While these studies suggest that only relatively low degrees of manipulation are tolerable, we claim that, besides establishing detection thresholds, it is important to know when the user's immersion breaks. We hypothesize that the degree of unnoticed manipulation is significantly different from the detection threshold when the user is immersed in a task. We conducted three studies: a) to devise an experimental paradigm to measure the threshold of limited immersion (TLI), b) to measure the TLI for slowly decreasing and increasing rotation gains, and c) to establish a baseline of cybersickness for our experimental setup. For rotation gains greater than 1.0, we found that immersion breaks quite late after the gain is detectable. However, for gains lesser than 1.0, some users reported a break of immersion even before established detection thresholds were reached. Apparently, the developed metric measures an additional quality of user experience. This article contributes to the development of effective spatial compression methods by utilizing the break of immersion as a benchmark for redirection techniques.

  18. Exact solution of the mixed spin-1/2 and spin-S Ising-Heisenberg diamond chain

    Directory of Open Access Journals (Sweden)

    L. Čanová

    2009-01-01

    Full Text Available The geometric frustration in a class of the mixed spin-1/2 and spin-S Ising-Heisenberg diamond chains is investigated by combining three exact analytical techniques: Kambe projection method, decoration-iteration transformation and transfer-matrix method. The ground state, the magnetization process and the specific heat as a function of the external magnetic field are particularly examined for different strengths of the geometric frustration. It is shown that the increase of the Heisenberg spin value S raises the number of intermediate magnetization plateaux, which emerge in magnetization curves provided that the ground state is highly degenerate on behalf of a sufficiently strong geometric frustration. On the other hand, all intermediate magnetization plateaux merge into a linear magnetization versus magnetic field dependence in the limit of classical Heisenberg spin S → ∞. The enhanced magnetocaloric effect with cooling rate exceeding the one of paramagnetic salts is also detected when the disordered frustrated phase constitutes the ground state and the external magnetic field is small enough.

  19. Propulsion health monitoring of a turbine engine disk using spin test data

    Science.gov (United States)

    Abdul-Aziz, Ali; Woike, Mark; Oza, Nikunj; Matthews, Bryan; Baakilini, George

    2010-03-01

    On line detection techniques to monitor the health of rotating engine components are becoming increasingly attractive options to aircraft engine companies in order to increase safety of operation and lower maintenance costs. Health monitoring remains a challenging feature to easily implement, especially, in the presence of scattered loading conditions, crack size, component geometry and materials properties. The current trend, however, is to utilize noninvasive types of health monitoring or nondestructive techniques to detect hidden flaws and mini cracks before any catastrophic event occurs. These techniques go further to evaluate materials' discontinuities and other anomalies that have grown to the level of critical defects which can lead to failure. Generally, health monitoring is highly dependent on sensor systems that are capable of performing in various engine environmental conditions and able to transmit a signal upon a predetermined crack length, while acting in a neutral form upon the overall performance of the engine system. Efforts are under way at NASA Glenn Research Center through support of the Intelligent Vehicle Health Management Project (IVHM) to develop and implement such sensor technology for a wide variety of applications. These efforts are focused on developing high temperature, wireless, low cost and durable products. Therefore, in an effort to address the technical issues concerning health monitoring of a rotor disk, this paper considers data collected from an experimental study using high frequency capacitive sensor technology to capture blade tip clearance and tip timing measurements in a rotating engine-like-disk-to predict the disk faults and assess its structural integrity. The experimental results collected at a range of rotational speeds from tests conducted at the NASA Glenn Research Center's Rotordynamics Laboratory will be evaluated using multiple data-driven anomaly detection techniques to identify anomalies in the disk. This study

  20. Measurements of the spin rotation parameter R in high energy elastic scattering and helicity amplitudes at Serpukhov energies

    International Nuclear Information System (INIS)

    Pierrard, J.; Bruneton, C.; Bystricky, J.; Cozzika, G.; Deregel, J.; Ducros, Y.; Gaidot, A.; Khantine-Langlois, F.; Lehar, F.; Lesquen, A. de; Merlo, J.P.; Miyashita, S.; Movchet, J.; Raoul, J.C.; Van Rossum, L.; Kanavets, V.P.

    1975-01-01

    The spin rotation parameter R in pp and π + p elastic scattering at 45GeV/c has been measured at the Serpukhov accelerator, for /t/ ranging from 0.2 to 0.5(GeV/c) 2 . The results are presented, together with previous R measurements at 3.8, 6, 16 and 40GeV/c, and are compared with the predictions of Regge pole models. The equality of the values for R in proton-proton and pion-proton scattering, within the experimental errors, is a test of factorization of the residues. An s-channel helicity amplitude analysis for pion-nucleon scattering at 40GeV/c is made using all available data. Significant results are obtained for the non flip amplitude in isoscalar exchange and for flip amplitudes on both isovector and isoscalar exchanges. The helicity flip in isoscalar exchange is non negligible. The energy dependence of this amplitude, at 6, 16 and 40GeV/c, is compared with predictions of Regge pole models [fr

  1. Virtual processes and superradiance in spin-boson modes

    International Nuclear Information System (INIS)

    Alcalde, M. Aparicio; Kullock, R.; Svaiter, N.F.

    2008-01-01

    We consider spin-boson models composed by a single bosonic mode and an ensemble of N identical two-level atoms. The situation where the coupling between the bosonic mode and the atoms generates real and virtual processes is studied, where the whole system is in thermal equilibrium with a reservoir at temperature β -1 . Phase transitions from ordinary fluorescence to super radiant phase in three different models is investigated. First a model where the coupling between the bosonic mode and the j - th atom is via the pseudo-spin operator σ (j) z is studied. Second, we investigate the generalized Dicke model, introducing different coupling constants between the single mode bosonic field and the environment, g 1 and g 2 for rotating and counter-rotating terms, respectively. Finally it is considered a modified version of the generalized Dicke model with intensity-dependent coupling in the rotating terms. In the first model the zero mode contributes to render the canonical entropy a negative quantity for low temperatures. The last two models presents phase transitions, even when only Hamiltonian terms which generates virtual processes are considered. (author)

  2. Distribution of rotational velocities for low-mass stars in the Pleiades

    International Nuclear Information System (INIS)

    Stauffer, J.R.; Hartmann, L.W.; Dominion Astrophysical Observatory, Victoria, Canada; Smithsonian Astrophysical Observatory, Cambridge, MA)

    1987-01-01

    The available spectral type and color data for late-type Pleiades members have been reanalyzed, and new reddening estimates are obtained. New photometry for a small number of stars and a compilation of H-alpha equivalent widths for Pleiades dwarfs are presented. These data are used to examine the location of the rapid rotators in color-magnitude diagrams and the correlation between chromospheric activity and rotation. It is shown that the wide range of angular momenta exhibited by Pleiades K and M dwarfs is not necessarily produced by a combination of main-sequence spin-downs and a large age spread; it can also result from a plausible spread in initial angular momenta, coupled with initial main-sequence spin-down rates that are only weakly dependent on rotation. The new reddening estimates confirm Breger's (1985) finding of large extinctions confined to a small region in the southern portion of the Merope nebula. 79 references

  3. Modeling the Anomalous Microwave Emission with Spinning Nanoparticles: No PAHs Required

    Energy Technology Data Exchange (ETDEWEB)

    Hensley, Brandon S. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Draine, B. T., E-mail: brandon.s.hensley@jpl.nasa.gov [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

    2017-02-20

    In light of recent observational results indicating an apparent lack of correlation between the anomalous microwave emission (AME) and mid-infrared emission from polycyclic aromatic hydrocarbons, we assess whether rotational emission from spinning silicate and/or iron nanoparticles could account for the observed AME without violating observational constraints on interstellar abundances, ultraviolet extinction, and infrared emission. By modifying the SpDust code to compute the rotational emission from these grains, we find that nanosilicate grains could account for the entirety of the observed AME, whereas iron grains could be responsible for only a fraction, even for extreme assumptions on the amount of interstellar iron concentrated in ultrasmall iron nanoparticles. Given the added complexity of contributions from multiple grain populations to the total spinning dust emission, as well as existing uncertainties due to the poorly constrained grain size, charge, and dipole moment distributions, we discuss generic, carrier-independent predictions of spinning dust theory and observational tests that could help identify the AME carrier(s).

  4. Free and binary rotation of polyatomic molecules

    International Nuclear Information System (INIS)

    Konyukhov, V K

    2003-01-01

    A modification of the quantum-mechanical theory of rotation of polyatomic molecules (binary rotation) is proposed, which is based on the algebra and representations of the SO(4) group and allows the introduction of the concept of parity, as in atomic spectroscopy. It is shown that, if an asymmetric top molecule performing binary rotation finds itself in a spatially inhomogeneous electric field, its rotational levels acquire the additional energy due to the quadrupole moment. The existence of the rotational states of polyatomic molecules that cannot transfer to the free rotation state is predicted. In particular, the spin isomers of a water molecule, which corresponds to such states, can have different absolute values of the adsorption energy due to the quadrupole interaction of the molecule with a surface. The difference in the adsorption energies allows one to explain qualitatively the behaviour of the ortho- and para-molecules of water upon their adsorption on the surface of solids in accordance with experimental data. (laser applications and other topics in quantum electronics)

  5. Ultrafast rotation in an amphidynamic crystalline metal organic framework.

    Science.gov (United States)

    Vogelsberg, Cortnie S; Uribe-Romo, Fernando J; Lipton, Andrew S; Yang, Song; Houk, K N; Brown, Stuart; Garcia-Garibay, Miguel A

    2017-12-26

    Amphidynamic crystals are an emergent class of condensed phase matter designed with a combination of lattice-forming elements linked to components that display engineered dynamics in the solid state. Here, we address the design of a crystalline array of molecular rotors with inertial diffusional rotation at the nanoscale, characterized by the absence of steric or electronic barriers. We solved this challenge with 1,4-bicyclo[2.2.2]octane dicarboxylic acid (BODCA)-MOF, a metal-organic framework (MOF) built with a high-symmetry bicyclo[2.2.2]octane dicarboxylate linker in a Zn 4 O cubic lattice. Using spin-lattice relaxation 1 H solid-state NMR at 29.49 and 13.87 MHz in the temperature range of 2.3-80 K, we showed that internal rotation occurs in a potential with energy barriers of 0.185 kcal mol -1 These results were confirmed with 2 H solid-state NMR line-shape analysis and spin-lattice relaxation at 76.78 MHz obtained between 6 and 298 K, which, combined with molecular dynamics simulations, indicate that inertial diffusional rotation is characterized by a broad range of angular displacements with no residence time at any given site. The ambient temperature rotation of the bicyclo[2.2.2]octane (BCO) group in BODCA-MOF constitutes an example where engineered rotational dynamics in the solid state are as fast as they would be in a high-density gas or in a low-density liquid phase.

  6. Musculoskeletal ultrasound: how to treat calcific tendinitis of the rotator cuff by ultrasound-guided single-needle lavage technique.

    Science.gov (United States)

    Lee, Kenneth S; Rosas, Humberto G

    2010-09-01

    The purpose of this video article is to illustrate the ultrasound appearance of calcium deposition in the rotator cuff and provide a detailed step-by-step protocol for performing the ultrasound-guided single-needle lavage technique for the treatment of calcific tendinitis with emphasis on patient positioning, necessary supplies, real-time lavage technique, and steroid injection into the subacromial subdeltoid bursa. Musculoskeletal ultrasound is well established as a safe, cost-effective imaging tool in diagnosing and treating common musculoskeletal disorders. Calcific tendinitis of the rotator cuff is a common disabling cause of shoulder pain. Although most cases are self-limiting, a subset of patients is refractory to conservative therapy and requires treatment intervention. Ultrasound-guided lavage is an effective and safe minimally-invasive treatment not readily offered in the United States as an alternative to surgery, perhaps because of the limited prevalence of musculoskeletal ultrasound programs and limited training. On completion of this video article, the participant should be able to develop an appropriate diagnostic and therapeutic algorithm for the treatment of calcific tendinitis of the rotator cuff using ultrasound.

  7. High-spin {gamma}-ray spectroscopy of {sup 124}Ba, {sup 124}Xe and {sup 125}Xe

    Energy Technology Data Exchange (ETDEWEB)

    Al-Khatib, Ali

    2008-08-18

    Rotational spectra had been observed for the first time in excited atomic nuclei in 1938. This observation was attributed to the deviation from spherical shape. In quantum mechanics, when a perfectly spherical system rotates, it appears identical when it is viewed from any direction and no point of reference exists to which the change in position can be identified. Therefore, rotation cannot be defined for spherical nuclei. If the shape deviates from spherical symmetry, the nucleus can rotate and rotational spectra are observed. Many nucleons contribute to the rotation which is referred to as collective excitation. Depending on the mass region, nuclei have different deformations and, therefore, different shapes. Many nuclei show larger deformation with increasing excitation energy. Transitional nuclei between spherical and strongly deformed regions of the nuclear chart are usually soft with respect to deformation changes. In the mass region around A{proportional_to}125, which is the subject of this thesis, nuclei are predicted to be soft with respect to deformation. Rotational motion leads to Coriolis-induced alignments of high-j nucleons, which are in this mass region predominantly protons and neutrons from the h{sub 11/2} unique-parity intruder subshells. The proton Fermi level lies in the lower part of the h{sub 11/2} subshell which favours prolate shape whereas the neutron Fermi level lies in the upper part of the h{sub 11/2} subshell which favours oblate shape. According to the opposite shape-driving forces of protons and neutrons, shape co-existence is expected and the interplay between the h{sub 11/2} proton and neutron orbitals is of great interest for spectroscopic investigations. In addition, superdeformation has been established in this mass region. An interesting observation in this mass region is that nuclei undergo a shape-change from collective prolate to non-collective oblate states at high spins. In this spin range the transitions within the

  8. Comparison of Passive Stiffness Changes in the Supraspinatus Muscle after Double-row and Knotless Transosseous-equivalent Rotator Cuff Repair Techniques: A Cadaveric Study

    Science.gov (United States)

    Hatta, Taku; Giambini, Hugo; Hooke, Alexander W.; Zhao, Chunfeng; Sperling, John W.; Steinmann, Scott P.; Yamamoto, Nobuyuki; Itoi, Eiji; An, Kai-Nan

    2016-01-01

    Purpose To investigate the alteration of passive stiffness in the supraspinatus muscle after double-row (DR) and knotless transosseous-equivalent (KL-TOE) repair techniques, using the shear wave elastography (SWE) in cadavers with rotator cuff tears. We also aimed to compare altered muscular stiffness after these repairs to that obtained from shoulders with intact rotator cuff tendon. Methods Twelve fresh-frozen cadaveric shoulders with rotator cuff tear (tear size; small [6], medium-large [6]) were used. Passive stiffness of four anatomical regions in the supraspinatus muscle was measured based on an established SWE method. Each specimen underwent DR and KL-TOE footprint repairs at 30° glenohumeral abduction. SWE values, obtained at 0°, 10°, 20°, 30°, 60°, and 90° abduction, were assessed in 3 different conditions: preoperative (torn) and postoperative conditions with the 2 techniques. The increase ratio of SWE values after repair was compared among the four regions to assess stiffness distribution. In addition, SWE values were obtained on 12 shoulders with intact rotator cuff tendons as control. Results In shoulders with medium-large size tears, supraspinatus muscles showed an increased passive stiffness after rotator cuff repairs, and this was significantly observed at adducted positions. KL-TOE repair showed uniform stiffness changes among the four regions of the supraspinatus muscle (mean, 189-218% increase after repair), whereas, DR repair caused a significantly heterogeneous stiffness distribution within the muscle (mean, 187-319% after repair, P = 0.002). Although a repair-induced increase in muscle stiffness was observed also in small size tear, there were no significant differences in repaired stiffness changes between DR and KL-TOE (mean, 127-138% and 127-130% after repairs, respectively). Shoulders with intact rotator cuff tendon showed uniform SWE values among the four regions of the supraspinatus muscle (mean, 38.2-43.0 kPa). Conclusion Passive

  9. Accretion by rotating magnetic neutron stars. III. Accretion torques and period changes in pulsating X-ray sources

    International Nuclear Information System (INIS)

    Ghosh, P.; Lamb, F.K.

    1979-01-01

    We use the solutions of the two-dimensional hydromagnetic equations obtained previously to calculate the torque on a magnetic neutron star accreting from a Keplerian disk. We find that the magnetic coupling between the star and the plasma outside the inner edge of the disk is appreciable. As a result of this coupling the spin-up torque on fast rotators is substantially less than that on slow rotators; for sufficiently high stellar angular velocities or sufficiently low accretion rates this coupling dominates that de to the plasma and the magnetic field at the inner edge of the disk, braking the star's rotation even while accretion, and hence X-ray emission, continues.We apply these results to pulsating X-ray sources, and show that the observed secular spin-up rates of all the sources in which this rate has been measured can be accounted for quantitatively if one assumes that these sources are accreting from Keplerian disks and have magnetic moments approx.10 29 --10 32 gauss cm 3 . The reduction of the torque on fast rotators provides a natural explanation of the spin-up rate of Her X-1, which is much below that expected for slow rotators. We show further that a simple relation between the secular spin-up rate : P and the quantity PL/sup 3/7/ adequately represents almost all the observational data, P and L being the pulse period and the luminosity of the source, respectively. This ''universal'' relation enables one to estimate any one of the parameters P, P, and L for a given source if the other two are known. We show that the short-term period fluctuations observed in Her X-1, Cen X-3, Vela X-1, and X Per can be accounted for quite naturally as consequences of torque variations caused by fluctuations in the mass transfer rate. We also indicate how the spin-down torque at low luminosities found here may account for the paradoxical existence of a large number of long-period sources with short spin-up time scales

  10. Inverse spin Hall effect from pulsed spin current in organic semiconductors with tunable spin-orbit coupling.

    Science.gov (United States)

    Sun, Dali; van Schooten, Kipp J; Kavand, Marzieh; Malissa, Hans; Zhang, Chuang; Groesbeck, Matthew; Boehme, Christoph; Valy Vardeny, Z

    2016-08-01

    Exploration of spin currents in organic semiconductors (OSECs) induced by resonant microwave absorption in ferromagnetic substrates is appealing for potential spintronics applications. Owing to the inherently weak spin-orbit coupling (SOC) of OSECs, their inverse spin Hall effect (ISHE) response is very subtle; limited by the microwave power applicable under continuous-wave (cw) excitation. Here we introduce a novel approach for generating significant ISHE signals in OSECs using pulsed ferromagnetic resonance, where the ISHE is two to three orders of magnitude larger compared to cw excitation. This strong ISHE enables us to investigate a variety of OSECs ranging from π-conjugated polymers with strong SOC that contain intrachain platinum atoms, to weak SOC polymers, to C60 films, where the SOC is predominantly caused by the curvature of the molecule's surface. The pulsed-ISHE technique offers a robust route for efficient injection and detection schemes of spin currents at room temperature, and paves the way for spin orbitronics in plastic materials.

  11. The Biomechanics of Cranial Forces During Figure Skating Spinning Elements.

    Science.gov (United States)

    Wang, David H; Kostyun, Regina O; Solomito, Matthew J

    2015-03-01

    Several facets of figure skating, such as the forces associated with jumping and landing, have been evaluated, but a comprehensive biomechanical understanding of the cranial forces associated with spinning has yet to be explored. The purpose of this case study was to quantify the cranial rotational acceleration forces generated during spinning elements. This case report was an observational, biomechanical analysis of a healthy, senior-level, female figure skating athlete who is part of an on-going study. A triaxial accelerometer recorded the gravitational forces (G) during seven different spinning elements. Our results found that the layback spin generated significant cranial force and these forces were greater than any of the other spin elements recorded. These forces led to physical findings of ruptured capillaries, dizziness, and headaches in our participant.

  12. Spin analysis and new effects in reflectivity measurements

    International Nuclear Information System (INIS)

    Fermon, C.

    1996-01-01

    We present two new effects in polarized neutron reflectivity. We show that we have a non symmetric spin-flip signal in reflectivity measurements on magnetic films when the external field is not negligible. This phenomenon is due to different Larmor precessions for the two spin states and has to be taken into account in some experiments. The second effect is still not understood but we present results indicating that the specular reflection on a non magnetic surface can induce a neutron beam depolarization or rotation. (authors)

  13. Spin-hydrodynamic equations with external disturbances and suitable Green's functions for superfluid 3He-B. New Onsager relations

    International Nuclear Information System (INIS)

    Galasiewicz, Z.M.

    1984-01-01

    The spin-hydrodynamic equations for superfluid 3 He-B are obtained for the case of external, time-dependent fields. On the basis of a microscopic approach, expressions are found for additional terms in equations containing these fields. Considering the linear response of the system to the switching on of external fields, formulas are found for suitable Green's functions (magnetization-magnetization, rotation-rotation, magnetization-rotation , rotation-magnetization). The rotation-rotation Green's function has the 1/q 2 singularity characteristic of superfluid systems. Connections between Green's functions lead to relations among kinetic coefficients nu, μ 1 , and μ 2 . It is also shown that there is a conserved quantity Q/sup (B)/ = div nu/sub s//sup (B)/ that describes sources or magnetic type charges (monopoles) of the superfluid velocity nu/sub s//sup (B)/. Comparison with the phenomenological approach suggests that Q/sup (B)/ is proportional to a pseudoscalar giving the projection of the spin density onto the vector describing that axis of rotation. 14 references

  14. On the origin of galaxies rotation in Ambarzumian's cosmology

    International Nuclear Information System (INIS)

    Muradyan, R.M.

    1975-01-01

    The paper discusses the possibility of explaining the origin of momentum of galaxies rotations and their clusters by the spin conservation of superheavy hadrons, whose decay results in formation of galaxies according to the ideas of Ambartsumyan's cosmogonic conception

  15. Correlation Effects and Hidden Spin-Orbit Entangled Electronic Order in Parent and Electron-Doped Iridates Sr_{2}IrO_{4}

    Directory of Open Access Journals (Sweden)

    Sen Zhou

    2017-10-01

    Full Text Available Analogs of the high-T_{c} cuprates have been long sought after in transition metal oxides. Because of the strong spin-orbit coupling, the 5d perovskite iridates Sr_{2}IrO_{4} exhibit a low-energy electronic structure remarkably similar to the cuprates. Whether a superconducting state exists as in the cuprates requires understanding the correlated spin-orbit entangled electronic states. Recent experiments discovered hidden order in the parent and electron-doped iridates, some with striking analogies to the cuprates, including Fermi surface pockets, Fermi arcs, and pseudogap. Here, we study the correlation and disorder effects in a five-orbital model derived from the band theory. We find that the experimental observations are consistent with a d-wave spin-orbit density wave order that breaks the symmetry of a joint twofold spin-orbital rotation followed by a lattice translation. There is a Berry phase and a plaquette spin flux due to spin procession as electrons hop between Ir atoms, akin to the intersite spin-orbit coupling in quantum spin Hall insulators. The associated staggered circulating J_{eff}=1/2 spin current can be probed by advanced techniques of spin-current detection in spintronics. This electronic order can emerge spontaneously from the intersite Coulomb interactions between the spatially extended iridium 5d orbitals, turning the metallic state into an electron-doped quasi-2D Dirac semimetal with important implications on the possible superconducting state suggested by recent experiments.

  16. The distribution of rotational velocities for low-mass stars in the Pleiades

    Science.gov (United States)

    Stauffer, John R.; Hartmann, Lee W.

    1987-01-01

    The available spectral type and color data for late-type Pleiades members have been reanalyzed, and new reddening estimates are obtained. New photometry for a small number of stars and a compilation of H-alpha equivalent widths for Pleiades dwarfs are presented. These data are used to examine the location of the rapid rotators in color-magnitude diagrams and the correlation between chromospheric activity and rotation. It is shown that the wide range of angular momenta exhibited by Pleiades K and M dwarfs is not necessarily produced by a combination of main-sequence spin-downs and a large age spread; it can also result from a plausible spread in initial angular momenta, coupled with initial main-sequence spin-down rates that are only weakly dependent on rotation. The new reddening estimates confirm Breger's (1985) finding of large extinctions confined to a small region in the southern portion of the Merope nebula.

  17. Spin-forming Project Report

    Energy Technology Data Exchange (ETDEWEB)

    Switzner, Nathan; Henry, Dick

    2009-03-20

    In a second development order, spin-forming equipment was again evaluated using the test shape, a hemispherical shell. In this second development order, pure vanadium and alloy titanium (Ti-6Al-4V) were spin-formed, as well as additional copper and 21-6-9 stainless. In the first development order the following materials had been spin-formed: copper (alloy C11000 ETP), 6061 aluminum, 304L stainless steel, 21-6-9 stainless steel, and tantalum-2.5% tungsten. Significant challenges included properly adjusting the rotations-per-minute (RPM), cracking at un-beveled edges and laser marks, redressing of notches, surface cracking, non-uniform temperature evolution in the titanium, and cracking of the tailstock. Lessons learned were that 300 RPM worked better than 600 RPM for most materials (at the feed rate of 800 mm/min); beveling the edges to lower the stress reduces edge cracking; notches, laser marks, or edge defects in the preform doom the process to cracking and failure; coolant is required for vanadium spin-forming; increasing the number of passes to nine or more eliminates surface cracking for vanadium; titanium develops a hot zone in front of the rollers; and the tailstock should be redesigned to eliminate the cylindrical stress concentrator in the center.

  18. Neutron spin echo spectroscopy. Its application to the study of the dynamics of polymers in solution; La spectrometrie par echos de spins de neutrons. Application a l'etude de la dynamique des polymeres en solution

    Energy Technology Data Exchange (ETDEWEB)

    Papoular, Robert

    1992-06-15

    This work focuses on Neutron Spin Echo (NSE) spectroscopy and on the NSE spectrometer MESS, which we have built at the L.L.B. (CE Saclay). After analyzing in detail the classical and quantum principles of this type of instrument, and illustrated them with optical analogies, we expound a simple formalism for the interpretation of polarized neutron experiments of the most general type. In a second part, we describe the MESS spectrometer extensively; its characteristics and performances as well as the first results obtained with this instrument. In particular, we include two papers showing how the neutron depolarization, spin rotation and echoes can be used to investigate high-Tc superconductors. The last part deals with the dynamics of Polymer-Polymer-Solvent ternary solutions and demonstrates how the Neutron Spin Echo technique becomes a privileged tool for such physico-chemical studies thanks to the joint use of NSE and contrast variation methods, coupled with the adequate ranges of time and scattering vectors accessible. Finally, we describe the specific case of partially deuterated polydimethyl-siloxane (PDMS) in semi-dilute solution in Toluene. We have experimentally and separately evidenced the cooperative and inter-diffusive diffusion modes predicted by the theory of Akcasu, Benoit, Benmouna et al. These results, obtained at the L.L.B. (CE Saclay) are the subject matter of the last paper included in this work. (author) [French] Ce memoire est centre sur la spectroscopie par echos de spins de neutrons, et plus particulierement, sur le spectrometre a echos de spins MESS que nous avons construit au L.L.B (CE/Saclay). Apres avoir detaille les principes classique et quantique de ce type d'instrument et les avoir illustres par des analogies optiques, nous detaillons un formalisme simple permettant d'interpreter les experiences utilisant les neutrons polarises dans le cas le plus general. Une seconde partie decrit de maniere approfondie le spectrometre MESS de Saclay

  19. Spin formalism and applications to new physics searches

    Energy Technology Data Exchange (ETDEWEB)

    Haber, H.E. [Univ. of California, Santa Cruz, CA (United States)

    1994-12-01

    An introduction to spin techniques in particle physics is given. Among the topics covered are: helicity formalism and its applications to the decay and scattering of spin-1/2 and spin-1 particles, techniques for evaluating helicity amplitudes (including projection operator methods and the spinor helicity method), and density matrix techniques. The utility of polarization and spin correlations for untangling new physics beyond the Standard Model at future colliders such as the LHC and a high energy e{sup +}e{sup {minus}} linear collider is then considered. A number of detailed examples are explored including the search for low-energy supersymmetry, a non-minimal Higgs boson sector, and new gauge bosons beyond the W{sup {+-}} and Z.

  20. Electron spin resonance and spin-valley physics in a silicon double quantum dot.

    Science.gov (United States)

    Hao, Xiaojie; Ruskov, Rusko; Xiao, Ming; Tahan, Charles; Jiang, HongWen

    2014-05-14

    Silicon quantum dots are a leading approach for solid-state quantum bits. However, developing this technology is complicated by the multi-valley nature of silicon. Here we observe transport of individual electrons in a silicon CMOS-based double quantum dot under electron spin resonance. An anticrossing of the driven dot energy levels is observed when the Zeeman and valley splittings coincide. A detected anticrossing splitting of 60 MHz is interpreted as a direct measure of spin and valley mixing, facilitated by spin-orbit interaction in the presence of non-ideal interfaces. A lower bound of spin dephasing time of 63 ns is extracted. We also describe a possible experimental evidence of an unconventional spin-valley blockade, despite the assumption of non-ideal interfaces. This understanding of silicon spin-valley physics should enable better control and read-out techniques for the spin qubits in an all CMOS silicon approach.