WorldWideScience

Sample records for hybrid magnetic trap

  1. Trapped magnetic-field properties of prototype for Gd-Ba-Cu-O/MgB2 hybrid-type superconducting bulk magnet

    Science.gov (United States)

    Naito, Tomoyuki; Mochizuki, Hidehiko; Fujishiro, Hiroyuki; Teshima, Hidekazu

    2016-03-01

    We have studied experimentally and numerically the trapped magnetic-field properties of a hybrid-type superconducting bulk magnet, which comprised an inner Gd-Ba-Cu-O (GdBCO) disk-bulk and an outer MgB2 ring-bulk, under field-cooled magnetization (FCM) and pulsed-field magnetization (PFM). The trapped field by FCM at the center of the hybrid bulk was 4.5 T at 20 K, which was 0.2 T higher than that of the inner GdBCO disk-bulk without MgB2 ring-bulk. The experimental results by FCM were quantitatively reproduced by the numerical estimations for a model, which makes it possible to understand the trapped field properties of the hybrid bulk. The total magnetic flux by FCM, which was estimated numerically, was enhanced by about 1.7 times from 0.91 mWb of the single GdBCO bulk to 1.53 mWb of the hybrid bulk. We also succeeded in magnetizing the whole hybrid bulk by applying multi-pulsed-fields. The central trapped field of 1.88 T was not enhanced, but the total magnetic flux, which was obtained experimentally, was evidently increased by 2.5 times (0.25 \\to 0.62 mWb) for the hybrid bulk. The obtained results suggest that the hybridization is effective to enhance the total magnetic flux. To confirm the reinforcing effect of the MgB2 ring to the GdBCO disk during the cooling and magnetization processes, we have measured the thermal dilatation, {\\text{}}{dL}({\\text{}}T)/{\\text{}}L(300 K), of the GdBCO, MgB2 and stainless steel. As a result, the thermal dilatation of MgB2 was smaller than that of GdBCO. MgB2 ring-bulk shows no compression effect to resist the hoop stress of the GdBCO disk-bulk during the FCM process. The reinforcing material such as the stainless steel ring must be set outside the GdBCO disk-bulk.

  2. Hybrid ion, atom and light trap

    CERN Document Server

    Jyothi, S; Ram, N Bhargava; Rangwala, S A

    2013-01-01

    We present an unique experimental arrangement which permits the simultaneous trapping and cooling of ions and neutral atoms, within a Fabry-Perot (FP) cavity. The versatility of this hybrid trap experiment enables a variety of studies with trapped mixtures. The motivations behind the production of such a hybrid trap system are explained, followed by details of how the experiment is put together. Several experiments that have been performed with this system are presented and some opportunities with this system are discussed. However the primary emphasis is focussed on the aspects that pertain to the trapped ions, in this hybrid system.

  3. Production of 87Rb Bose-Einstein condensates in a hybrid trap

    Institute of Scientific and Technical Information of China (English)

    Duan Ya-Fan; Jiang Bo-Nan; Sun Jian-Fang; Liu Kang-Kang; Xu Zhen; Wang Yu-Zhu

    2013-01-01

    We report a rapid evaporative cooling method using a hybrid trap which is composed of a quadrupole magnetic trap and a one-beam optical dipole trap.It contains two kinds of evaporative coolings to reach the quantum degeneracy:initial radio-frequency (RF) enforced evaporative cooling in the quadrupole magnetic trap and further runaway evaporative cooling in the optical dipole trap.The hybrid trap does not require a very high power laser such as that in the traditional pure optical trap,but still has a deep trap depth and a large trap volume,and has better optical access than the normal magnetic trap like the quadrupole-Ioffe-configuration (QUIC) cloverleaf trap.A high trap frequency can be easily realized in the hybrid trap to enhance the elastic collision rate and shorten the evaporative cooling time.In our experiment,pure Bose-Einstein condensates (BECs) with about 1 × 105 atoms can be realized in 6 s evaporative cooling in the optical dipole trap.

  4. A magnetic particle micro-trap for large trapping surfaces

    KAUST Repository

    Gooneratne, Chinthaka P.

    2012-01-08

    Manipulation of micron-size magnetic particles of the superparamagnetic type contributes significantly in many applications like controlling the antibody/antigen binding process in immunoassays. Specifically, more target biomolecules can be attached/tagged and analyzed since the three dimensional structure of the magnetic particles increases the surface to volume ratio. Additionally, such biomolecular-tagged magnetic particles can be easily manipulated by an external magnetic field due to their superparamagnetic behavior. Therefore, magnetic particle- based immunoassays are extensively applied in micro-flow cytometry. The design of a square-loop micro-trap as a magnetic particle manipulator as well as numerical and experimental analysis is presented. Experimental results showed that the micro-trap could successfully trap and concentrate magnetic particles from a large to a small area with a high spatial range.

  5. Optical and Magnetic Trapping of Potassium 39

    Science.gov (United States)

    Ensher, Jason; Cornell, Eric; Cataliotti, Francesco; Fort, Chiara; Marin, Francesco; Prevedelli, Marco; Inguscio, Massimo; Ricci, Leonardo; Tino, Guglielmo

    1998-05-01

    We present measurments of optical trapping and cooling and magnetic trapping of ^39K in a double-MOT apparatus. (Optics Lett. 21, 290(1996)) We have measured light-assisted collisional loss rates from our second MOT over a range of trap light intensities. At an intensity of 10 mW/cm^2 we find a loss rate parameter β of 2 x 10-11 cc/s. β increases with trap light intensity and is consistent with the values measured by Williamson and Walker (JOSA B 12, 1393 (1995)). We also present studies of the temperature of atoms in a MOT of ^39K. Under certain conditions of repump light intensity and trap light detuning we measure temperatures nearly as low as the Doppler Limit. Finally, we report on prelimiary results of magnetic trapping in which we have trapped several 10^7 atoms in a quadrupole magnetic trap.

  6. Polaronic trapping in magnetic semiconductors

    Science.gov (United States)

    Raebiger, Hannes

    2012-02-01

    GaN doped with iron is an interesting candidate material for magnetic semiconductors, as p-d coupling between the localized Fe-d and extended N-p hole states is expected to facilitate long-range ferromagnetic alignment of the Fe spins [1]. This picture of extended states in GaN:Fe, however, falls apart due to a polaronic localization of the hole carriers nearby the Fe impurities. To elucidate the carrier localization in GaN:Fe and related iron doped III-V semiconductors, I present a systematic study using self-interaction corrected density-functional calculations [2]. These calculations predict three distinct scenarios. (i) Some systems do sustain extended host-like hole states, (ii) some exhibit polaronic trapping, (iii) and some exhibit carrier trapping at Fe-d orbitals. These behaviors are described in detail to give an insight as to how to distinguish them experimentally. I thank T. Fujita, C. Echeverria-Arrondo, and A. Ayuela for their collaboration.[4pt] [1] T. Dietl et al, Science, 287, 1019 (2000).[0pt] [2] S. Lany and A. Zunger, Phys. Rev. B, 80, 085202 (2009).

  7. Signal enhancement using a switchable magnetic trap

    Science.gov (United States)

    Beer, Neil Reginald [Pleasanton, CA

    2012-05-29

    A system for analyzing a sample including providing a microchannel flow channel; associating the sample with magnetic nanoparticles or magnetic polystyrene-coated beads; moving the sample with said magnetic nanoparticles or magnetic polystyrene-coated beads in the microchannel flow channel; holding the sample with the magnetic nanoparticles or magnetic polystyrene-coated beads in a magnetic trap in the microchannel flow channel; and analyzing the sample obtaining an enhanced analysis signal. An apparatus for analysis of a sample includes magnetic particles connected to the sample, a microchip, a flow channel in the microchip, a source of carrier fluid connected to the flow channel for moving the sample in the flow channel, an electromagnet trap connected to the flow line for selectively magnetically trapping the sample and the magnetic particles, and an analyzer for analyzing the sample.

  8. Magnetic Trapping of Molecules via Optical Loading and Magnetic Slowing

    CERN Document Server

    Lu, Hsin-I; Hemmerling, Boerge; Piskorski, Julia; Doyle, John M

    2013-01-01

    Calcium monofluoride (CaF) is magnetically slowed and trapped using optical pumping. Starting from a collisionally cooled slow beam, CaF with an initial velocity of ~ 30 m/s is slowed via magnetic forces as it enters a 800 mK deep magnetic trap. Employing two-stage optical pumping, CaF is irreversibly loaded into the trap via two scattered photons. We observe a trap lifetime exceeding 500 ms, limited by background collisions. This method paves the way for cooling and magnetic trapping of chemically diverse molecules without closed cycling transitions.

  9. Enhanced Magnetic Trap Loading for Atomic Strontium

    OpenAIRE

    Barker, D.S.; Reschovsky, B. J.; Pisenti, N. C.; Campbell, G. K.

    2015-01-01

    We report on a technique to improve the continuous loading of atomic strontium into a magnetic trap from a Magneto-Optical Trap (MOT). This is achieved by adding a depumping laser tuned to the 3P1 to 3S1 (688-nm) transition. The depumping laser increases atom number in the magnetic trap and subsequent cooling stages by up to 65 % for the bosonic isotopes and up to 30 % for the fermionic isotope of strontium. We optimize this trap loading strategy with respect to the 688-nm laser detuning, int...

  10. Cryogenic Hybrid Magnetic Bearing

    Science.gov (United States)

    Meeks, Crawford R.; Dirusso, Eliseo; Brown, Gerald V.

    1994-01-01

    Cryogenic hybrid magnetic bearing is example of class of magnetic bearings in which permanent magnets and electromagnets used to suspend shafts. Electromagnets provide active control of position of shaft. Bearing operates at temperatures from -320 degrees F (-196 degrees C) to 650 degrees F (343 degrees C); designed for possible use in rocket-engine turbopumps, where effects of cryogenic environment and fluid severely limit lubrication of conventional ball bearings. This and similar bearings also suitable for terrestrial rotating machinery; for example, gas-turbine engines, high-vacuum pumps, canned pumps, precise gimbals that suspend sensors, and pumps that handle corrosive or gritty fluids.

  11. Magnetic Trapping of Cold Bromine Atoms

    CERN Document Server

    Rennick, C J; Doherty, W G; Softley, T P

    2014-01-01

    Magnetic trapping of bromine atoms at temperatures in the milliKelvin regime is demonstrated for the first time. The atoms are produced by photodissociation of Br$_2$ molecules in a molecular beam. The lab-frame velocity of Br atoms is controlled by the wavelength and polarization of the photodissociation laser. Careful selection of the wavelength results in one of the pair of atoms having sufficient velocity to exactly cancel that of the parent molecule, and it remains stationary in the lab frame. A trap is formed at the null point between two opposing neodymium permanent magnets. Dissociation of molecules at the field minimum results in the slowest fraction of photofragments remaining trapped. After the ballistic escape of the fastest atoms, the trapped slow atoms are only lost by elastic collisions with the chamber background gas. The measured loss rate is consistent with estimates of the total cross section for only those collisions transferring sufficient kinetic energy to overcome the trapping potential...

  12. Enhanced Magnetic Trap Loading for Atomic Strontium

    CERN Document Server

    Barker, D S; Pisenti, N C; Campbell, G K

    2015-01-01

    We report on a technique to improve the continuous loading of atomic strontium into a magnetic trap from a Magneto-Optical Trap (MOT). This is achieved by adding a depumping laser tuned to the 3P1 to 3S1 (688-nm) transition. The depumping laser increases atom number in the magnetic trap and subsequent cooling stages by up to 65 % for the bosonic isotopes and up to 30 % for the fermionic isotope of strontium. We optimize this trap loading strategy with respect to the 688-nm laser detuning, intensity, and beam size. To understand the results, we develop a one-dimensional rate equation model of the system, which is in good agreement with the data. We discuss the use of other transitions in strontium for accelerated trap loading and the application of the technique to other alkaline-earth-like atoms.

  13. Enhanced magnetic trap loading for atomic strontium

    Science.gov (United States)

    Barker, D. S.; Reschovsky, B. J.; Pisenti, N. C.; Campbell, G. K.

    2015-10-01

    We report on a technique to improve the continuous loading of atomic strontium into a magnetic trap from a magneto-optical trap. This is achieved by adding a depumping laser tuned to the P31→S31 (688-nm) transition. The depumping laser increases atom number in the magnetic trap and subsequent cooling stages by up to 65% for the bosonic isotopes and up to 30% for the fermionic isotope of strontium. We optimize this trap loading strategy with respect to the 688-nm laser detuning, intensity, and beam size. To understand the results, we develop a one-dimensional rate equation model of the system, which is in good agreement with the data. We discuss the use of other transitions in strontium for accelerated trap loading and the application of the technique to other alkaline-earth-like atoms.

  14. Magnetic trapping of cold bromine atoms.

    Science.gov (United States)

    Rennick, C J; Lam, J; Doherty, W G; Softley, T P

    2014-01-17

    Magnetic trapping of bromine atoms at temperatures in the millikelvin regime is demonstrated for the first time. The atoms are produced by photodissociation of Br2 molecules in a molecular beam. The lab-frame velocity of Br atoms is controlled by the wavelength and polarization of the photodissociation laser. Careful selection of the wavelength results in one of the pair of atoms having sufficient velocity to exactly cancel that of the parent molecule, and it remains stationary in the lab frame. A trap is formed at the null point between two opposing neodymium permanent magnets. Dissociation of molecules at the field minimum results in the slowest fraction of photofragments remaining trapped. After the ballistic escape of the fastest atoms, the trapped slow atoms are lost only by elastic collisions with the chamber background gas. The measured loss rate is consistent with estimates of the total cross section for only those collisions transferring sufficient kinetic energy to overcome the trapping potential.

  15. Magnetic field of a combined plasma trap

    Science.gov (United States)

    Kotenko, V. G.; Moiseenko, V. E.; Ågren, O.

    2012-06-01

    This paper presents numerical simulations performed on the structure of a magnetic field created by the magnetic system of a combined plasma trap. The magnetic system includes the stellarator-type magnetic system and one of the mirror-type. For the stellarator type magnetic system the numeric model contains a magnetic system of an l=2 torsatron with the coils of an additional toroidal magnetic field. The mirror-type magnetic system element is considered as being single current-carrying turn enveloping the region of existence of closed magnetic surfaces of the torsatron. The calculations indicate the existence of a vast area of the values of the additional magnetic field magnitude and magnetic field of the single turn where, in principle, the implementation of the closed magnetic surface configuration is quite feasible.

  16. Invited Article: Development of high-field superconducting Ioffe magnetic traps

    Science.gov (United States)

    Yang, L.; Brome, C. R.; Butterworth, J. S.; Dzhosyuk, S. N.; Mattoni, C. E. H.; McKinsey, D. N.; Michniak, R. A.; Doyle, J. M.; Golub, R.; Korobkina, E.; O'Shaughnessy, C. M.; Palmquist, G. R.; Seo, P.-N.; Huffman, P. R.; Coakley, K. J.; Mumm, H. P.; Thompson, A. K.; Yang, G. L.; Lamoreaux, S. K.

    2008-03-01

    We describe the design, construction, and performance of three generations of superconducting Ioffe magnetic traps. The first two are low current traps, built from four racetrack shaped quadrupole coils and two solenoid assemblies. Coils are wet wound with multifilament NbTi superconducting wires embedded in epoxy matrices. The magnet bore diameters are 51 and 105mm with identical trap depths of 1.0T at their operating currents and at 4.2K. A third trap uses a high current accelerator-type quadrupole magnet and two low current solenoids. This trap has a bore diameter of 140mm and tested trap depth of 2.8T. Both low current traps show signs of excessive training. The high current hybrid trap, on the other hand, exhibits good training behavior and is amenable to quench protection.

  17. Testing the Model of Oscillating Magnetic Traps

    Science.gov (United States)

    Szaforz, Ż.; Tomczak, M.

    2015-01-01

    The aim of this paper is to test the model of oscillating magnetic traps (the OMT model), proposed by Jakimiec and Tomczak ( Solar Phys. 261, 233, 2010). This model describes the process of excitation of quasi-periodic pulsations (QPPs) observed during solar flares. In the OMT model energetic electrons are accelerated within a triangular, cusp-like structure situated between the reconnection point and the top of a flare loop as seen in soft X-rays. We analyzed QPPs in hard X-ray light curves for 23 flares as observed by Yohkoh. Three independent methods were used. We also used hard X-ray images to localize magnetic traps and soft X-ray images to diagnose thermal plasmas inside the traps. We found that the majority of the observed pulsation periods correlates with the diameters of oscillating magnetic traps, as was predicted by the OMT model. We also found that the electron number density of plasma inside the magnetic traps in the time of pulsation disappearance is strongly connected with the pulsation period. We conclude that the observations are consistent with the predictions of the OMT model for the analyzed set of flares.

  18. Hybrid Magnetics and Power Applications

    DEFF Research Database (Denmark)

    Mo, Wai Keung; Paasch, Kasper

    A hybrid magnetic approach, merging two different magnetic core properites such as ferrite and iron powder cores, is an effective solution for power converter applications. It can offer similar magnetic properties to that of magnetic powder cores but showing less copper loss than powder cores...

  19. Magnetic Trapping of Cold Methyl Radicals

    CERN Document Server

    Liu, Yang; Djuricanin, Pavle; Zhou, Sida; Zhong, Wei; Mittertreiner, Tony; Carty, David; Momose, Takamasa

    2016-01-01

    We have demonstrated that a supersonic beam of methyl radicals (CH3) in the ground rotational state of both para and ortho species has been slowed down to a standstill with a magnetic molecular decelerator, and successfully captured spatially in an anti-Helmholtz magnetic trap for > 1 s. The translational temperature of the trapped CH3 radicals was about 200 mK. The methyl radical is a non-polar polyatomic molecule, which is predicted to be an ideal system for further cooling below 1 mK via sympathetic cooling with ultracold atoms. In addition, it is a highly reactive intermediate that plays an important role in various processes in cold environments such as planetary atmospheres and the interstellar medium. The demonstrated trapping capability of methyl radicals opens up various possibilities for realizing ultracold ensembles of molecules towards Bose-Einstein condensation of polyatomic molecules and investigations of reactions governed by quantum statistics.

  20. Magnetic Trapping of Cold Methyl Radicals

    Science.gov (United States)

    Liu, Yang; Vashishta, Manish; Djuricanin, Pavle; Zhou, Sida; Zhong, Wei; Mittertreiner, Tony; Carty, David; Momose, Takamasa

    2017-03-01

    We have demonstrated that a supersonic beam of methyl radicals (CH3 ) in the ground rotational state of both para and ortho species has been slowed down to standstill with a magnetic molecular decelerator, and successfully captured spatially in an anti-Helmholtz magnetic trap for >1 s . The trapped CH3 radicals have a mean translational temperature of about 200 mK with an estimated density of >5.0 ×1 07 cm-3 . The methyl radical is an ideal system for the study of cold molecules not only because of its high reactivities at low temperatures, but also because further cooling below 1 mK is plausible via sympathetic cooling with ultracold atoms. The demonstrated trapping capability of methyl radicals opens up various possibilities for realizing ultracold ensembles of molecules towards Bose-Einstein condensation of polyatomic molecules and investigations of reactions governed by quantum statistics.

  1. Thermalization of magnetically trapped metastable helium

    CERN Document Server

    Browaeys, A; Sirjean, O; Poupard, J; Nowak, S; Boiron, D; Westbrook, C I; Aspect, Alain

    2001-01-01

    We have observed thermalization by elastic collisions of magnetically trapped metastable helium atoms. Our method directly samples the reconstruction of a thermal energy distribution after the application of an RF knife. The relaxation time of our sample towards equilibrium gives an elastic collision rate constant close to the unitarity limit.

  2. Hybrid superconductor magnet bearings

    Science.gov (United States)

    Chu, Wei-Kan

    1995-01-01

    Hybrid superconductor magnet bearings (HSMB's) utilize high temperature superconductors (HTS's) together with permanent magnets to form a frictionless interface between relatively rotating parts. They are low mass, stable, and do not incur expenditure of energy during normal operation. There is no direct physical contact between rotor and stator, and hence there is no wear and tear. However, just as any other applications of HTS's, it requires a very cold temperature to function. Whereas this might be perceived as a disadvantage on earth, it is of no great concern in space or on the moon. To astronomers, the moon is an excellent site for an observatory, but the cold and dusty vacuum environment on the moon precludes the use of mechanical bearings on the telescope mounts. Furthermore, drive mechanisms with very fine steps, and hence bearings with extremely low friction are needed to track a star from the moon, because the moon rotates very slowly. All aspects considered, the HSMB is about the only candidate that fits in naturally. Here, we present a design for one such bearing, capable of supporting a telescope that weighs about 3 lbs on Earth.

  3. 32 tesla hybrid magnet system

    Energy Technology Data Exchange (ETDEWEB)

    Leupold, M.J.; Iwasa, Y.; Weggel, R.J. (MIT Cambridge (U.S.A.))

    1984-01-01

    The paper describes the design and construction of a hybrid magnet system to generate 32T with 9MW of electrical power. The system consist of an 11T niobium-titanium superconducting magnet, a 1.8K/4.2K cryostat, and a high-performance, water-cooled Bitter magnet, all of which are discussed in the paper.

  4. Hybrid Magnetics and Power Applications

    DEFF Research Database (Denmark)

    Mo, Wai Keung; Paasch, Kasper

    2017-01-01

    . In order to prevent ferrite core saturation, placing an effective air gap within the ferrite core is a key method to obtain optimum hybrid magnetic performance. Furthermore, a relatively large inductance at low loading current is an excellent way to minimze power loss in order to achieve high efficiency...

  5. Ion tail formation by cascade trapping in lower-hybrid heating experiments

    Energy Technology Data Exchange (ETDEWEB)

    Gell, Y.; Nakach, R.

    1986-03-01

    The possibility of the operation of a multistep trapping process in the interaction of the ions of a plasma with lower--hybrid waves, leading to the formation of a tail in the ion velocity distribution, is investigated. Considering waves propagating perpendicularly to a homogeneous magnetic field, it is found that the spectral nature of the lower-hybrid excitation and the dependency of the perpendicular wave vector on the radial coordinate of the torus are the characteristics of the system which enable this cascading acceleration to take place. The conditions and limitations for the operation of this mechanism are discussed.

  6. Magnetic Properties and Intergranular Action in Bonded Hybrid Magnets

    Institute of Scientific and Technical Information of China (English)

    Hua Zhenghe; Li Shandong; Han Zhida; Wang Dunhui; Zhong Wei; Gu Benxi; Lu Mu; Zhang Jianrong; Du Youwei

    2007-01-01

    Magnetic properties and intergranular action in bonded hybrid magnets, based on NdFeB and strontium ferrite powders were investigated. The long-range magnetostatic interaction and short-range exchange coupling interaction existed simultaneously in bonded hybrid magnets, and neither of them could be neglected. Some magnetic property parameters of hybrid magnets could be approximately obtained by adding the hysteresis loops of two magnets pro rata.

  7. Production of rubidium Bose-Einstein condensate in an optically-plugged magnetic quadrupole trap

    CERN Document Server

    Zhang, Dong-Fang; Kong, Ling-Ran; Li, Kai; Jiang, Kai-Jun

    2016-01-01

    We have experimentally produced rubidium Bose-Einstein condensate in an optically-plugged magnetic quadrupole (OPQ) trap. A far blue-detuned focused laser beam with a wavelength of 532 nm is plugged in the center of the magnetic quadrupole trap to increase the number of trapped atoms and suppress the heating. A radio frequency (RF) evaporative cooling in the magneto-optical hybrid trap is applied to decrease the atom temperature into degeneracy. The atom number of the condensate is $1.2(0.4)\\times10^5$ and the temperature is below 100 nK. We have also studied characteristic behaviors of the condensate, such as phase space density (PSD), condensate fraction and anisotropic expansion.

  8. On Galateas - magnetic traps with plasma-embedded conductors

    Energy Technology Data Exchange (ETDEWEB)

    Morozov, A I [Russian Research Centre ' Kurchatov Institute' , Moscow (Russian Federation); Savel' ev, V V [M.V. Keldysh Institute for Applied Mathematics, Russian Academy of Sciences, Moscow (Russian Federation)

    1998-11-30

    The introduction of plasma-embedded magnetically insulated current-carrying conductors into a plasma trap magnetic system radically increases the number of possible trap designs. The present review focuses on the studies of {beta} = 1 Galateas conducted in the 1990s. Both general and design-specific Galatea properties are discussed and for a number of specific schemes analytical and numerical calculations are performed. Experimental data on a number of electrical discharge Galateas are presented. (reviews of topical problems)

  9. Surface-electrode trap with an integrated permanent magnet for generating a magnetic-field gradient at trapped ions

    Science.gov (United States)

    Kawai, Yuji; Shimizu, Kenji; Noguchi, Atsushi; Urabe, Shinji; Tanaka, Utako

    2017-01-01

    We report on a surface-electrode trap with SmCo magnets arranged in a quadrupole configuration underneath the trap electrode. Because the distance between the magnets and the trapped ions can be as little as several hundred micrometers, a large magnetic field is produced without any heat management. The magnetic-field gradient was measured using the Zeeman splitting of a single trapped 40Ca+ ion at several positions, and a field gradient of 36 T m-1 was obtained. Such a field gradient is useful for the generation of a state-dependent force, which is important for quantum simulation and/or quantum gate operation using radio-frequency or microwave radiation.

  10. Surface-electrode trap with an integrated permanent magnet for generating a magnetic-field gradient at trapped ions

    CERN Document Server

    Kawai, Yuji; Noguchi, Atsushi; Urabe, Shinji; Tanaka, Utako

    2016-01-01

    We report on a surface-electrode trap with SmCo magnets arranged in a quadrupole configuration underneath the trap electrode. Because the distance between the magnets and the trapped ions can be as little as several hundred micrometers, a large magnetic field is produced without any heat management. The magnetic-field gradient was measured using the Zeeman splitting of a single trapped $^{40}$Ca$^+$ ion at several positions, and a field gradient of 36 T/m was obtained. Such a field gradient is useful for the generation of a state-dependent force, which is important for quantum simulation and/or quantum gate operation using radio-frequency or microwave radiation.

  11. Enhanced Magnetic Trap Loading for Alkaline-Earth Atoms

    Science.gov (United States)

    Reschovsky, Benjamin J.; Barker, Daniel S.; Pisenti, Neal C.; Campbell, Gretchen K.

    2016-05-01

    We report on a technique to improve the continuous loading of atomic strontium into a magnetic trap from a Magneto-Optical Trap (MOT). This is achieved by adding a depumping laser addressing the 3P1 level. For the 3P1 -->3S1 (688-nm) transition in strontium, the depumping laser increases atom number in the magnetic trap and subsequent cooling stages by up to 65 % for the bosonic isotopes and up to 30 % for the fermionic isotope. We optimize this trap loading strategy with respect to the 688-nm laser detuning, intensity, and beam size. To understand the results, we develop a one-dimensional rate equation model of the system, which is in good agreement with the data. We discuss the use of other transitions in strontium for accelerated trap loading and the application of the technique to other alkaline-earth-like atoms.

  12. Effect of a transverse magnetic field on the parameters of a trap using a combination of the second and third harmonics of a helical field

    Energy Technology Data Exchange (ETDEWEB)

    Akshanov, B.S.; Pyatov, V.N.; Sebko, V.P.; Tyupa, V.I.

    1975-01-01

    In an analysis of the effect of a transverse magnetic field on the parameters of a trap using a combination of the second and third harmonics of a helical field, an averaging method is used to calculate the parameters of a hybrid (l = 2 plus l = 3) stellarator magnetic trap in a homogeneous, external, transverse magnetic field B/sub perpendicular/. The stabilizing effect of the second harmonic of the magnetic field on the configuration is discussed.

  13. Electron Cloud Trapping in Recycler Combined Function Dipole Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Antipov, Sergey A. [Chicago U.; Nagaitsev, S. [Fermilab

    2016-10-04

    Electron cloud can lead to a fast instability in intense proton and positron beams in circular accelerators. In the Fermilab Recycler the electron cloud is confined within its combined function magnets. We show that the field of combined function magnets traps the electron cloud, present the results of analytical estimates of trapping, and compare them to numerical simulations of electron cloud formation. The electron cloud is located at the beam center and up to 1% of the particles can be trapped by the magnetic field. Since the process of electron cloud build-up is exponential, once trapped this amount of electrons significantly increases the density of the cloud on the next revolution. In a Recycler combined function dipole this multiturn accumulation allows the electron cloud reaching final intensities orders of magnitude greater than in a pure dipole. The multi-turn build-up can be stopped by injection of a clearing bunch of 1010 p at any position in the ring.

  14. Tornado type closed magnetic trap for an ECR source

    CERN Document Server

    Abramova, K B; Voronin, A V; Zorin, V G

    1999-01-01

    We propose to use a Tornado type closed magnetic trap for creation of a source of mul-ticharged ions with plasma heating by microwave radiation. Plasma loss in closed traps is deter-mined by diffusion across the magnetic field, which increases substantially plasma confinement time as compared to the classical mirror trap [1]. We propose to extract ions with the aid of additional coils which partially destroy the closed structure of the magnetic lines in the trap, but don not influence the total confinement time. This allows for producing a controlled plasma flux that depends on the magnetic field of the additional coil. The Tornado trap also possesses merits such as an opportunity to produce high magnetic fields up to 3 T, which makes possible heating and confinement of plasma with a high density of electrons; plasma stability to magneto-hydrodynamic perturbations because the magnetic field structure corresponds to the "min B" configuration; and relatively low costs. All estimates and calculations were carrie...

  15. Atom Chip for Transporting and Merging Magnetically Trapped Atom Clouds

    CERN Document Server

    Hänsel, W; Hommelhoff, P; Hänsch, T W

    2000-01-01

    We demonstrate an integrated magnetic ``atom chip'' which transports cold trapped atoms near a surface with very high positioning accuracy. Time-dependent currents in a lithographic conductor pattern create a moving chain of magnetic potential wells; atoms are transported in these wells while remaining confined in all three dimensions. We achieve fluxes up to 10^6 /s with a negligible heating rate. An extension of this ``atomic conveyor belt'' allows the merging of magnetically trapped atom clouds by unification of two Ioffe-Pritchard potentials. Under suitable conditions, the clouds merge without loss of phase space density. We demonstrate this unification process experimentally.

  16. Cold atom trap with zero residual magnetic field: the ac magneto-optical trap.

    Science.gov (United States)

    Harvey, Matthew; Murray, Andrew James

    2008-10-24

    A novel atom trap is described using alternating current to generate the magnetic B field, together with high speed polarization switching of the damping laser field. This combination produces a trap as effective as a standard magneto-optical trap (MOT), with the advantage that the average B field is zero. No net current is hence induced in surrounding conductive elements, and the B field produced by the ac MOT is found to switch off >300 times faster than a conventional MOT. New experiments can hence be performed, including charged particle probing or detection of the cold target ensemble.

  17. Hybrid Shielding for Magnetic Fields

    Science.gov (United States)

    Mullins, David; Royal, Kevin

    2017-01-01

    Precision symmetry measurements such as the search for the electric dipole moment of the neutron require magnetic shielding rooms to reduce the ambient field to the pT scale. The massive mu-metal sheets and large separation between layers make these shield rooms bulky and expensive. Active field cancellation systems used to reduce the surrounding field are limited in uniformity of cancellation. A novel approach to reducing the space between shield layers and increasing the effectiveness of active cancellation is to combine the two systems into a hybrid system, with active and passive layers interspersed. We demonstrate this idea in a prototype with an active layer sandwiched between two passive layers of shielding.

  18. Compact setup for the production of $^{87}$Rb $|F = 2, m_F = +2\\rangle$ Bose-Einstein condensates in a hybrid trap

    CERN Document Server

    Nolli, Raffaele; Marmugi, Luca; Wickenbrock, Arne; Renzoni, Ferruccio

    2016-01-01

    We present a compact experimental apparatus for Bose-Einstein condensation of $^{87}$Rb in the $|F = 2, m_F = +2\\rangle$ state. A pre-cooled atomic beam of $^{87}$Rb is obtained by using an unbalanced magneto-optical trap, allowing controlled transfer of trapped atoms from the first vacuum chamber to the science chamber. Here, atoms are transferred to a hybrid trap, as produced by overlapping a magnetic quadrupole trap with a far-detuned optical trap with crossed beam configuration, where forced radiofrequency evaporation is realized. The final evaporation leading to Bose-Einstein condensation is then performed by exponentially lowering the optical trap depth. Control and stabilization systems of the optical trap beams are discussed in detail. The setup reliably produces a pure condensate in the $|F = 2, m_F = +2\\rangle$ state in 50 s, which include 33 s loading of the science magneto-optical trap and 17 s forced evaporation.

  19. Axisymmetric Magnetic Mirror Fusion-Fission Hybrid

    Energy Technology Data Exchange (ETDEWEB)

    Moir, R. W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Martovetsky, N. N. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Molvik, A. W. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Ryutov, D. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Simonen, T. C. [Univ. of California, Berkeley, CA (United States)

    2011-05-13

    The achieved performance of the gas dynamic trap version of magnetic mirrors and today’s technology we believe are sufficient with modest further efforts for a neutron source for material testing (Q=Pfusion/Pinput~0.1). The performance needed for commercial power production requires considerable further advances to achieve the necessary high Q>>10. An early application of the mirror, requiring intermediate performance and intermediate values of Q~1 are the hybrid applications. The Axisymmetric Mirror has a number of attractive features as a driver for a fusion-fission hybrid system: geometrical simplicity, inherently steady-state operation, and the presence of the natural divertors in the form of end tanks. This level of physics performance has the virtue of low risk and only modest R&D needed and its simplicity promises economy advantages. Operation at Q~1 allows for relatively low electron temperatures, in the range of 4 keV, for the DT injection energy ~ 80 keV. A simple mirror with the plasma diameter of 1 m and mirror-to-mirror length of 35 m is discussed. Simple circular superconducting coils are based on today’s technology. The positive ion neutral beams are similar to existing units but designed for steady state. A brief qualitative discussion of three groups of physics issues is presented: axial heat loss, MHD stability in the axisymmetric geometry, microstability of sloshing ions. Burning fission reactor wastes by fissioning actinides (transuranics: Pu, Np, Am, Cm, .. or just minor actinides: Np, Am, Cm, …) in the hybrid will multiply fusion’s energy by a factor of ~10 or more and diminish the Q needed to less than 1 to overcome the cost of recirculating power for good economics. The economic value of destroying actinides by fissioning is rather low based on either the cost of long-term storage or even deep geologic disposal so most of the revenues of hybrids will come from electrical power. Hybrids that obtain revenues from

  20. Manipulating Neutral Atoms in Chip-Based Magnetic Traps

    Science.gov (United States)

    Aveline, David; Thompson, Robert; Lundblad, Nathan; Maleki, Lute; Yu, Nan; Kohel, James

    2009-01-01

    Several techniques for manipulating neutral atoms (more precisely, ultracold clouds of neutral atoms) in chip-based magnetic traps and atomic waveguides have been demonstrated. Such traps and waveguides are promising components of future quantum sensors that would offer sensitivities much greater than those of conventional sensors. Potential applications include gyroscopy and basic research in physical phenomena that involve gravitational and/or electromagnetic fields. The developed techniques make it possible to control atoms with greater versatility and dexterity than were previously possible and, hence, can be expected to contribute to the value of chip-based magnetic traps and atomic waveguides. The basic principle of these techniques is to control gradient magnetic fields with suitable timing so as to alter a trap to exert position-, velocity-, and/or time-dependent forces on atoms in the trap to obtain desired effects. The trap magnetic fields are generated by controlled electric currents flowing in both macroscopic off-chip electromagnet coils and microscopic wires on the surface of the chip. The methods are best explained in terms of examples. Rather than simply allowing atoms to expand freely into an atomic waveguide, one can give them a controllable push by switching on an externally generated or a chip-based gradient magnetic field. This push can increase the speed of the atoms, typically from about 5 to about 20 cm/s. Applying a non-linear magnetic-field gradient exerts different forces on atoms in different positions a phenomenon that one can exploit by introducing a delay between releasing atoms into the waveguide and turning on the magnetic field.

  1. Shrink-induced sorting using integrated nanoscale magnetic traps.

    Science.gov (United States)

    Nawarathna, Dharmakeerthi; Norouzi, Nazila; McLane, Jolie; Sharma, Himanshu; Sharac, Nicholas; Grant, Ted; Chen, Aaron; Strayer, Scott; Ragan, Regina; Khine, Michelle

    2013-02-11

    We present a plastic microfluidic device with integrated nanoscale magnetic traps (NSMTs) that separates magnetic from non-magnetic beads with high purity and throughput, and unprecedented enrichments. Numerical simulations indicate significantly higher localized magnetic field gradients than previously reported. We demonstrated >20 000-fold enrichment for 0.001% magnetic bead mixtures. Since we achieve high purity at all flow-rates tested, this is a robust, rapid, portable, and simple solution to sort target species from small volumes amenable for point-of-care applications. We used the NSMT in a 96 well format to extract DNA from small sample volumes for quantitative polymerase chain reaction (qPCR).

  2. Superconducting Bulk Magnets: Very High Trapped Fields and Cracking

    OpenAIRE

    Gruss, S; Fuchs, G.; Krabbes, G.; Verges, P.; Stover, G.; Muller, K. -H.; Fink, J; L. Schultz

    2001-01-01

    Improved trapped fields are reported for bulk melt-textured YBa2Cu3O7-x (YBCO) material in the temperature range between 20 K and 50 K. Trapped fields up to 12.2 T were obtained at 22 K on the surface of single YBCO disks (with Ag and Zn additions). In YBCO mini-magnets, maximum trapped fields of 16 T (at 24 K) and of 11.2 T (at 47 K) were achieved using (Zn + Ag) and Zn additions, respectively. In all cases, the YBCO disks were encapsulated in steel tubes in order to reinforce the material a...

  3. Switchable Magnetic Bottles and Field Gradients for Particle Traps

    CERN Document Server

    Vogel, Manuel; Quint, Wolfgang; von Lindenfels, David; Wiesel, Marco

    2014-01-01

    Versatile methods for the manipulation of individual quantum systems, such as confined particles, have become central elements in current developments in precision spectroscopy, frequency standards, quantum information processing, quantum simulation, and alike. For atomic and some subatomic particles, both neutral and charged, a precise control of magnetic fields is essen- tial. In this paper, we discuss possibilities for the creation of specific magnetic field configurations which find appli- cation in these areas. In particular, we pursue the idea of a magnetic bottle which can be switched on and off by transition between the normal and the superconducting phase of a suitable material in cryogenic environments, for example in trap experiments in moderate magnetic fields. Methods for a fine-tuning of the magnetic field and its linear and quadratic components in a trap are presented together with possible applications.

  4. Dense stellar matter with trapped neutrinos under strong magnetic fields

    CERN Document Server

    Rabhi, A

    2009-01-01

    We investigate the effects of strong magnetic fields on the equation of state of dense stellar neutrino-free and neutrino-trapped matter. Relativistic nuclear models both with constant couplings (NLW) and with density dependent parameters (DDRH) and including hyperons are considered . It is shown that at low densities neutrinos are suppressed in the presence of the magnetic field. The magnetic field reduces the strangeness fraction of neutrino-free matter and increases the strangeness fraction of neutrino-trapped matter. The mass-radius relation of stars described by these equations of state are determined. The magnetic field makes the overall equation of state stiffer and the stronger the field the larger the mass of maximum mass star and the smaller the baryon density at the center of the star. As a consequence in the presence of strong magnetic fields the possibility that a protoneutron star evolves to a blackhole is smaller.

  5. Trapped magnetic field measurements on HTS bulk by peak controlled pulsed field magnetization

    Energy Technology Data Exchange (ETDEWEB)

    Ida, Tetsuya; Watasaki, Masahiro [Department of Electronic Control Engineering, Hiroshima National College of Maritime Technology, 4272-1, Higashino, Ohsakikamijima-cho, Toyota-gun, Hiroshima 725-0231 (Japan); Kimura, Yosuke [Kawasaki Heavy Industries, Ltd. Technical Institute System Technology Development Centre 1-1, Kawasaki-cho, Akashi-shi, Hyogo 673-8666 (Japan); Miki, Motohiro; Izumi, Mitsuru, E-mail: ida@hiroshima-cmt.ac.j [Department of Marine Electronics and Mechanical Engineering, Tokyo University of Marine Science and Technology, 2-1-6, Etchu-jima, Koto-ku, Tokyo 135-8533 (Japan)

    2010-06-01

    For the past several years, we have studied the high-temperature superconducting (HTS) synchronous motor assembled with melt-textured Gd-Ba-Cu-O bulk magnets. If the single pulse field magnetizes a bulk effectively, size of electrical motor will become small for the strong magnetic field of the HTS magnets without reducing output power of motor. In the previous study, we showed that the HTS bulk was magnetized to excellent cone-shape magnetic field distribution by using the waveform control pulse magnetization (WCPM) method. The WCPM technique made possible the active control of the waveform on which magnetic flux motion depended. We generated the pulse waveform with controlled risetime for HTS bulk magnetization to suppress the magnetic flux motion which decreases magnetization efficiency. The pulsed maximum magnetic flux density with slow risetime is not beyond the maximum magnetic flux density which is trapped by the static field magnetization. But, as for applying the pulse which has fast risetime, the magnetic flux which exceed greatly the threshold penetrates the bulk and causes the disorder of the trapped magnetic distribution. This fact suggests the possibility that the threshold at pulsed magnetization influences the dynamic magnetic flux motion. In this study, Gd-Ba-Cu-O bulk is magnetized by the controlled arbitrary trapezoidal shape pulse, of which the maximum magnetic flux density is controlled not to exceed the threshold. We will present the trapped magnetic characteristics and the technique to generate the controlled pulsed field.

  6. Quench-induced trapping of magnetic flux in annular

    DEFF Research Database (Denmark)

    Aaroe, M.; Monaco, R.; Rivers, R.;

    2008-01-01

    over 4 orders of magnitude. After the quench the result of the spontaneous production of topological defects, trapped fluxons, is unambiguously observed as zero-field steps in the DC I-V characteristic of the junction. A power-law scaling behavior of trapping probability versus quench rate is found...... with a critical exponent of 0.5 (within experimental error). The main experimental challenges are to generate many identical quenches with accurate cooling rate, to automate data analysis and acquisition, and to suppress external magnetic fields and noise by passive magnetic shielding and compensation....

  7. Field Evaluation of a Novel Mos-Hole Trap and Naphtha Compared with BG Sentinel Trap and Mosquito Magnet X Trap to Collect Adult Mosquitoes.

    Science.gov (United States)

    Xue, Rui-De; Smith, Michael L; Yi, Hoonbook; Kline, Daniel L

    2015-03-01

    The novel Mos-Hole trap™ with liquid attractant naphtha™ from Korea was compared with BG Sentinel™ trap and Mosquito Magnet X™ trap for field collection of adult mosquitoes in St. Johns County, northeastern Florida, from May to October 2013. The novel Mos-Hole trap baited with naphtha (liquid attractant) collected similar numbers of mosquitoes, compared with the number of mosquitoes caught by BG Sentinel traps baited with BG Lure™. Both Mos-Hole and BG Sentinel traps collected a significantly greater number of mosquitoes compared with the numbers collected by Mosquito Magnet X traps. In other field evaluations when switching lures, the Mos-Hole traps baited with BG Lure caught more mosquitoes than the BG Sentinel trap baited with liquid naphtha attractant. The results showed that the novel Mos-Hole trap has the potential to be used as an additional effective sampling tool for population surveillance and control of adult mosquitoes.

  8. Search for magnetic monopoles trapped in matter

    CERN Document Server

    Jeon, H

    1995-01-01

    There have been many searches for magnetic monopoles in flight, but few for monopoles in matter. We have searched for magnetic monopoles in meteorites, schists, ferromanganese nodules, iron ores and other materials. The detector was a superconducting induction coil connected to a SQUID (Superconducting Quantum Interference Device) with a room temperature bore 15 cm in diameter. We tested a total of more than 331 kg of material including 112 kg of meteorites. We found no monopole and conclude the overall monopole/nucleon ratio in the samples is <1.2 \\times 10^{-29} with a 90\\% confidence level.

  9. A biodetection method using magnetic particles and micro traps

    KAUST Repository

    Li, Fuquan

    2012-03-09

    The general working principle of magnetoresistive sensors for biological applications is to specifically attach bioanalytesto magnetic particles and then detect the particles that are immobilized on the sensor surface. The immobilization of the particles on the sensor surface commonly uses biomolecular interactions, e.g., antigen-antibody. Thus, the sensor surface needs to be functionalized via biological treatments in order to capture certain bioanalytes. In the presented work, a new method is proposed, which does not rely on functionalization of the sensor surface. Current carrying microstructures in combination with mechanical micro traps are used to immobilize magnetic particles. Analyte detection is based on the difference in size between bare magnetic particles and particles with analyte attached, which causes a different number of particles to be captured in the micro traps.

  10. A magnetic method to concentrate and trap biological targets

    KAUST Repository

    Li, Fuquan

    2012-11-01

    Magnetoresistive sensors in combination with magnetic particles have been used in biological applications due to, e.g., their small size and high sensitivity. A growing interest is to integrate magnetoresistive sensors with microchannels and electronics to fabricate devices that can perform complex analyses. A major task in such systems is to immobilize magnetic particles on top of the sensor surface, which is required to detect the particles\\' stray field. In the presented work, a bead concentrator, consisting of gold microstructures, at the bottom of a microchannel, is used to attract and move magnetic particles into a trap. The trap is made of a chamber with a gold microstructure underneath and is used to attract and immobilize a defined number of magnetic beads. In order to detect targets, two kinds of solutions were prepared; one containing only superparamagnetic particles, the other one containing beads with the protein Bovine serum albumin as the target and fluorescent markers. Due to the size difference between bare beads and beads with target, less magnetic beads were immobilized inside the volume chamber in case of magnetic beads with target as compared to bare magnetic beads. © 1965-2012 IEEE.

  11. Measurements of flux pumping activation of trapped field magnets

    Energy Technology Data Exchange (ETDEWEB)

    Weinstein, Roy; Parks, Drew; Sawh, Ravi-Persad [Texas Center for Superconductivity, 202 Houston Science Center, University of Houston, Houston, TX 77204-5002 (United States); Davey, Kent [Physics Department, 617 Science and Research Building I, University of Houston, Houston, TX 77204-5005 (United States)

    2010-11-15

    Large grains of high temperature superconducting (HTS) material can be utilized as trapped field magnets (TFMs). Persistent currents are set up in the HTS when it is cooled in a magnetic field, or exposed to a magnetic field after cooling. TFMs have been improved over the past two decades by the efforts of a large number of worldwide research groups. However, applications using TFMs have lagged, in part due to the problem of high fields needed for activation. We describe herein experiments designed to observe the behaviour of TFM activation using repeated applications of low fields (called 'pumping'). Significant partial activation is obtained using a non-uniform pumping field (e.g., a small permanent magnet) which is higher in the centre of the HTS than at the periphery. Cooling in zero field followed by pumping with such a field results in trapping the full applied field, in comparison to half of the applied field being trapped by cooling in zero field followed by application of a uniform field. We find that for partial activation by cooling in a field and subsequent activation by pumping, the resulting fields are additive. We also conclude that for activation by fluxoid pumping, creep assists the process.

  12. Force among magnetic nanocylinders trapped in triangular arrays

    Energy Technology Data Exchange (ETDEWEB)

    Cisternas, E., E-mail: ecisternas@ufro.cl [Departamento de Ciencias Fisicas, Universidad de La Frontera, Casilla 54-D, Temuco (Chile); Vasquez, Y.; Vogel, E.E. [Departamento de Ciencias Fisicas, Universidad de La Frontera, Casilla 54-D, Temuco (Chile)

    2012-03-15

    We study the effect of the forces among magnetic nanocylinders trapped in a membrane such as those used to produce them. The interaction force between two parallel and identical magnetic nanocylinders is revisited to obtain expressions that can later be used to add them both in a discrete and a continuum approximation. At this point a particular geometry has to be assumed and we use a particular configuration reported in the literature, namely, a bundle of parallel magnetic cylinders trapped in a circular membrane. When a strong enough external magnetic field is imposed along the axis of the membrane (also along the axes of the cylinders) all magnetizations point along this direction and cylinders repel among themselves. In a first approximation we will consider a soft enough membrane so energy is mostly relaxed through a deformation of the membrane leaving the magnetization of the cylinders basically as it was in the absence of external field. Then we obtain the forces among these cylinders by two methods: one summing the contributions of a discrete number of objects and another one in which we consider a continuum distribution of them to reach larger systems. Numerical evaluation of these forces can reach 50 mdyn approximately. Such forces will act on the membrane at the positions of the magnetic cylinders; in the case of a circular silicon membrane of radius 1.0 mm the radial expansion of the membrane can be of the order of 1 nm. This effect could be larger for softer membranes. A discussion of experimental techniques to detect this phenomenon is also done followed by the proposal of a possible application. - Highlights: Black-Right-Pointing-Pointer Force among magnetic nanocylinders ordered in triangular arrays within a membrane. Black-Right-Pointing-Pointer Macroscopic effect on a membrane containing cylinders by applying an external magnetic field. Black-Right-Pointing-Pointer Membrane deformation due to magnetostatic interaction among cylinders.

  13. Design and Synthesis of Microscale Opto-Magnetic Trapping Handles

    Science.gov (United States)

    Lawson, Joseph L.

    Opto-Magnetic Trapping (OMT) is a novel micromanipulation technology capable of translating particles with nanometer precision and producing forces on the order of pico-Newtons. OMT combines the benefits of optical trapping (OT) to manipulate handle particles in translational directions and magnetic trapping (MT) to provide rotational control. This combined manipulation technology shows promise for applications ranging from novel single molecule force spectroscopy to advanced manufacturing of smart micro or nano structures. Successful OMT requires handles containing material properties amenable to both OT and MT individually. Since these material properties are traditionally exclusive, novel anisotropic handles must be synthesized to accommodate both micromanipulation technologies. This body of research advances the state of the art in micromanipulation technology by addressing the fundamental material incompatibility issues associated with OMT. Novel micro-scale "patchy" handle particles were fabricated using a glancing angle deposition (GLAD) process. Due to their composite design combining dielectric and ferromagnetic materials, these particles successfully demonstrated OMT manipulation. These particles, along with the developed GLAD fabrication process, improve upon the current state of the art by enabling the robust synthesis of a wider range of particle sizes. Furthermore, the magnetic moments of these particles can be more accurately controlled over a wider range including producing magnetic moments grater than is capable with current techniques. A thorough numerical simulation was also conducted to identify the variation of OT performance of these patchy particles with respect to standard dielectric-only OT handles. While variations in trapping location do exist, they were found to be within an acceptable range for OMT applications and are still capable of manipulation with nanometer precision.

  14. Estimating effects from trapped magnetic fluxes in superconducting magnetic levitation measurement

    Institute of Scientific and Technical Information of China (English)

    Masakazu Nakanishi

    2008-01-01

    Superconducting magnetic levitation measurement is one of the most promising approaches to define mass standard based on the fundamental physical constants. However, the present system has unknown factors causing error larger than 50 ppm. We examined the effects of magnetic fluxes trapped in the superconducting coil and the superconducting floating body. When fluxes were trapped in either coil or floating body, their effects were able to be cancelled by reversing polarities of current and magnetic field, as had been believed. However, fluxes trapped in both coil and body induced an attractive force between them and caused error. In order to reduce the fluxes, the coil and the floating body should be cooled in low magnetic field in magnetic and electromagnetic shields.

  15. Properties of Magnetized Quark-Hybrid Stars

    CERN Document Server

    Orsaria, M; Vucetich, H; Weber, F

    2011-01-01

    The structure of a magnetized quark-hybrid stars (QHS) is modeled using a standard relativistic mean-field equation of state (EoS) for the description of hadronic matter. For quark matter we consider a bag model EoS which is modified perturbatively to account for the presence of a uniform magnetic field. The mass-radius (M-R) relationship, gravitational redshift and rotational Kepler periods of such stars are compared with those of standard neutron stars (NS).

  16. First Ever Storage of Ultracold Neutrons in a Magnetic Trap Made of Permanent Magnets.

    Science.gov (United States)

    Ezhov, V F; Andreev, A Z; Glushkov, A A; Glushkov, A G; Groshev, M N; Knyazkov, V A; Krygin, G B; Ryabov, V L; Serebrov, A P; Bazarov, B A; Geltenbort, P; Hartman, F J; Paul, S; Picker, R; Zimmer, O; Kovrizhnykh, N A

    2005-01-01

    Further improvement in the accuracy of any neutron lifetime experiment by means of ultracold neutrons (UCN) in material bottles is limited due to unavoidable systematic effects when the UCN are reflected from the walls. However, such effects can be excluded in principle if magnetic trapping of UCN is used. The storage of UCN in a small magnetic trap made of permanent magnets was demonstrated for the first time ever. The measured storage time in this feasibility study was (882 ± 16) s. At this level of accuracy no depolarization was observed.

  17. Photodissociation of trapped Rb$^+_2$ : Implications for hybrid molecular ion-atom trapping

    CERN Document Server

    Jyothi, S; Dutta, Sourav; Allouche, A R; Vexiau, Romain; Dulieu, Olivier; Rangwala, S A

    2016-01-01

    We observe direct photodissociation of trapped $^{85}$Rb$_2^+$ molecular ions in the presence of cooling light for the $^{85}$Rb magneto optical trap (MOT). Vibrationally excited Rb$_{2}^{+}$ ions are created by photoionization of Rb$_{2}$ molecules formed photoassociatively in the rubidium (Rb) MOT and are trapped in a modified spherical Paul trap co-centric with the MOT. The decay rate of the trapped Rb$_{2}^{+}$ ion signal in the presence of the MOT cooling light is measured and agreement with our calculated rates for molecular ion photodissociation is established. The photodissociation mechanism due to the MOT light is expected to be active and therefore universal for all homonuclear diatomic alkali metal molecular ions.

  18. Cold atom-ion experiments in hybrid traps

    CERN Document Server

    Härter, Arne

    2013-01-01

    In the last 5 years, a novel field of physics and chemistry has developed in which cold trapped ions and ultracold atomic gases are brought into contact with each other. Combining ion traps with traps for neutral atoms yields a variety of new possibilities for research and experiments. These range from studies of cold atom-ion collisions and atom-ion chemistry to applications in quantum information science and condensed matter related research. In this article we give a brief introduction into this new field and describe some of the perspectives for its future development.

  19. Influence of High Harmonics of Magnetic Fields on Trapped Magnetic Fluxes in HTS Bulk

    Science.gov (United States)

    Yamagishi, K.; Miyagi, D.; Tsukamoto, O.

    Various kinds of HTS bulk motors are proposed and have been developed. Generally, those motors are driven by semiconductor inverters and currents fed to the armature windings contain high harmonics. Therefore, the bulks are exposed to high harmonics magnetic fields and AC losses are produced in the bulks. The AC losses deteriorate the efficiency of the motors and cause temperature rise of the bulks which decrease the trapped magnetic fluxes of the bulks. Usually, electro-magnetic shielding devices are inserted between the bulks and armature windings. However, the shielding devices degrade compactness of the motors. Therefore, it is important to have knowledge of the influence of the high harmonics magnetic fields on the AC losses and trapped magnetic fluxes of the bulk for optimum design of the shielding devices. In this work, the authors experimentally study the influence of high harmonics magnetic fields.

  20. A hybrid density functional study on the electron and hole trap states in anatase titanium dioxide.

    Science.gov (United States)

    Yamamoto, Takenori; Ohno, Takahisa

    2012-01-14

    We present a theoretical study on electron and hole trap states in the bulk and (001) surface of anatase titanium dioxide using screened hybrid density functional calculations. In both the bulk and surface, calculations suggest that the neutral and ionized oxygen vacancies are possible electron traps. The doubly ionized oxygen vacancy is the most stable in the bulk, and is a candidate for a shallow donor in colorless anatase crystals. The hole trap states are localized at oxygen anions in both the bulk and surface. The self-trapped electron centered at a titanium cation cannot be produced in the bulk, but can be formed at the surface. The electron trap level at the surface oxygen vacancy is consistent with observations by photoelectron spectroscopy. The optical absorptions and luminescence in UV-irradiated anatase nanoparticles are found to come from the surface self-trapped hole and the surface oxygen vacancy.

  1. A new ring-shape high-temperature superconducting trapped-field magnet

    Science.gov (United States)

    Sheng, Jie; Zhang, Min; Wang, Yawei; Li, Xiaojian; Patel, Jay; Yuan, Weijia

    2017-09-01

    This paper presents a new trapped-field magnet made of second-generation high-temperature superconducting (2G HTS) rings. This so-called ring-shape 2G HTS magnet has the potential to provide much stronger magnetic fields relative to existing permanent magnets. Compared to existing 2G HTS trapped- field magnets, e.g. 2G HTS bulks and stacks, this new ring-shape 2G HTS magnet is more flexible in size and can be made into magnets with large dimensions for industrial applications. Effective magnetization is the key to being able to use trapped-field magnets. Therefore, this paper focuses on the magnetization mechanism of this new magnet using both experimental and numerical methods. Unique features have been identified and quantified for this new type of HTS magnet in the field cooling and zero field cooling process. The magnetization mechanism can be understood by the interaction between shielding currents and the penetration of external magnetic fields. An accumulation in the trapped field was observed by using multiple pulse field cooling. Three types of demagnetization were studied to measure the trapped-field decay for practical applications. Our results show that this new ring-shape HTS magnet is very promising in the trapping of a high magnetic field. As a super-permanent magnet, it will have a significant impact on large-scale industrial applications, e.g. the development of HTS machines with a very high power density and HTS magnetic resonance imaging devices.

  2. Superior homogeneity of trapped magnetic field in superconducting MgB2 bulk magnets

    Science.gov (United States)

    Ishihara, A.; Akasaka, T.; Tomita, M.; Kishio, K.

    2017-03-01

    Homogeneity of trapped magnetic field in radial and circumferential directions of high temperature superconducting bulk magnets, MgB2 (T c ˜38.3 K) and YBa2Cu3O y (T c ˜91.5 K), have been measured. In polycrystalline MgB2 bulks, the circularity of trapped magnetic field in a cylindrical disk is over 97% at 20-32.5 K, while that of YBa2Cu3O y was ˜87% at 77 K. Magnetic field distribution of MgB2 bulk was satisfactorily homogeneous and these measurements suggest MgB2 bulks with highly efficient cryocoolers should be very useful for novel high field permanent magnet applications.

  3. Superconducting Magnetic Energy Storage:. Conventional and Trapped Field

    Science.gov (United States)

    Rabinowitz, Mario

    Superconducting magnetic energy storage (SMES) is a most efficient system for energy storage because it stores energy directly in electrical form. The SMES concept is described and analyzed with an examination of its economic viability. The impact of high-temperature supeconductivity on SMES is explored, and a trapped energy storage (TES) innovation that may have beneficial technical and economic ramifications is introduced. In addition to presenting a broad overview, this paper may be of help to those making an evaluation of the potential impact of SMES/TES on the development of new energy sources, and to determine for which energy sources it is most appropriate.

  4. Inducing transparency with large magnetic response and group indices by hybrid dielectric metamaterials.

    Science.gov (United States)

    Chen, Cheng-Kuang; Lai, Yueh-Chun; Yang, Yu-Hang; Chen, Chia-Yun; Yen, Ta-Jen

    2012-03-26

    We present metamaterial-induced transparency (MIT) phenomena with enhanced magnetic fields in hybrid dielectric metamaterials. Using two hybrid structures of identical-dielectric-constant resonators (IDRs) and distinct-dielectric-constant resonators (DDRs), we demonstrate a larger group index (ng~354), better bandwidth-delay product (BDP~0.9) than metallic-type metamaterials. The keys to enable these properties are to excite either the trapped mode or the suppressed mode resonances, which can be managed by controlling the contrast of dielectric constants between the dielectric resonators in the hybrid metamaterials.

  5. High performance hybrid magnetic structure for biotechnology applications

    Science.gov (United States)

    Humphries, David E [El Cerrito, CA; Pollard, Martin J [El Cerrito, CA; Elkin, Christopher J [San Ramon, CA

    2009-02-03

    The present disclosure provides a high performance hybrid magnetic structure made from a combination of permanent magnets and ferromagnetic pole materials which are assembled in a predetermined array. The hybrid magnetic structure provides means for separation and other biotechnology applications involving holding, manipulation, or separation of magnetic or magnetizable molecular structures and targets. Also disclosed are further improvements to aspects of the hybrid magnetic structure, including additional elements and for adapting the use of the hybrid magnetic structure for use in biotechnology and high throughput processes.

  6. Levitation performance of the magnetized bulk high- Tc superconducting magnet with different trapped fields

    Science.gov (United States)

    Liu, W.; Wang, J. S.; Liao, X. L.; Zheng, S. J.; Ma, G. T.; Zheng, J.; Wang, S. Y.

    2011-03-01

    To a high- Tc superconducting (HTS) maglev system which needs large levitation force density, the magnetized bulk high- Tc superconductor (HTSC) magnet is a good candidate because it can supply additional repulsive or attractive force above a permanent magnet guideway (PMG). Because the induced supercurrent within a magnetized bulk HTSC is the key parameter for the levitation performance, and it is sensitive to the magnetizing process and field, so the magnetized bulk HTSC magnets with different magnetizing processes had various levitation performances, not only the force magnitude, but also its force relaxation characteristics. Furthermore, the distribution and configuration of the induced supercurrent are also important factor to decide the levitation performance, especially the force relaxation characteristics. This article experimentally investigates the influences of different magnetizing processes and trapped fields on the levitation performance of a magnetized bulk HTSC magnet with smaller size than the magnetic inter-pole distance of PMG, and the obtained results are qualitatively analyzed by the Critical State Model. The test results and analyses of this article are useful for the suitable choice and optimal design of magnetized bulk HTSC magnets.

  7. Mobile magnetic traps for manipulation of magnetically labeled and unlabeled cells

    Science.gov (United States)

    Henighan, Thomas; Chen, Aaron; Vieira, Greg; Hauser, Adam; Yang, Fengyuan; Chalmers, Jeffrey; Sooryakumar, Ratnasingham

    2010-03-01

    Magnetic forces are frequently used for the manipulation of biological cells because magnetic fields are typically easier to use and have fewer effects on the cells than optical or electrical fields. While magnetic forces are typically used for bulk separation, it is considerably harder to magnetically manipulate a single cell, or a small number of cells. In this study we employ reprogrammable magnetization profiles created through lithographically patterned ferromagnetic disks as a template for producing highly localized trapping fields. The resulting magnetic field gradients can be modulated by an external magnetic field enabling directed forces to be applied on, (a) single, or a small number of immunomagnetically labeled biological cells and, (b) magnetic microspheres that act as magnetically actuated force transmitting probes to navigate fluid-borne unlabeled cells with micrometer precision. We demonstrate the mobile traps by remotely transporting and arranging, with programmed routines (a la joystick), T-lymphocyte and leukemia cells on the platform. Without producing damage, the forces transport the cells with speeds up to 20 microns/sec across a silicon platform to predetermined sites.

  8. A hybrid transducer to magnetically and ultrasonically evaluate magnetic fluids.

    Science.gov (United States)

    Bruno, Alexandre Colello; Pavan, Théo Z; Baffa, Oswaldo; Carneiro, Antonio Adilton Oliveira

    2013-09-01

    Ultrasound, magnetic fields, and optical techniques have been explored for clinical diagnosis and therapy. However, these techniques have limitations. In this study, we constructed and characterized a transducer to magnetically and ultrasonically investigate samples labeled with magnetic particles. The transducer is a hybrid system consisting of an ac biosusceptometer (ACB) and an ultrasonic transducer. The basic operation principle consisted of measuring the magnetization and microvibrations of ferromagnetic particles (37 and 70 μm) mixed in yogurt and excited by an external alternating magnetic field generated by the ACB's excitation coils. The vibration of the ferromagnetic particles was measured in phantoms using a Doppler ultrasonic transducer; we verified the sensitivity to detecting the vibrations at low concentrations of ferromagnetic material (~1%). The responses of the susceptometer and Doppler ultrasound linearly depended on the voltage level applied to the magnetizing coils at low ferromagnetic particle concentrations (⩽ 5%). We also conducted a repeatability test on the prototype, which indicated a deviation of 0.94% and 0.25% in the Doppler and susceptometric measurements, respectively. We can conclude that the hybrid transducer technique has potential clinical applications.

  9. Neutron Lifetime Measurement Using Magnetically Trapped Ultracold Neutrons

    Science.gov (United States)

    Huffer, Craig; Huffman, P. R.; Schelhammer, K. W.; Dewey, M. S.; Huber, M. G.; Hughes, P. P.; Mumm, H. P.; Thompson, A. K.; Coakley, K.; Yue, A. T.; O'Shaughnessy, C. M.

    2017-01-01

    The neutron beta-decay lifetime is important in both nuclear astrophysics and in understanding weak interactions in the framework of the Standard Model. An experiment based at the NIST Center for Neutron Research was designed to address statistical and systematic limitations of former measurements. In our approach, a beam of 0.89 nm neutrons is incident on a superfluid 4He target within the minimum field region of an Ioffe-type magnetic trap. Some of the neutrons are subsequently downscattered by single phonons in the helium to low energies (decays the energetic electron produces a scintillation signal in the helium that is detected in real time using photomultiplier tubes. The current measurement is limited by larger than expected systematic corrections. We will discuss the result of the latest dataset and comment on the potential of future measurements.

  10. Trapping ultracold atoms in a sub-micron-period triangular magnetic lattice

    Science.gov (United States)

    Wang, Y.; Tran, T.; Surendran, P.; Herrera, I.; Balcytis, A.; Nissen, D.; Albrecht, M.; Sidorov, A.; Hannaford, P.

    2017-07-01

    We report the trapping of ultracold 87Rb atoms in a 0.7-μ m-period two-dimensional triangular magnetic lattice on an atom chip. The magnetic lattice is created by a lithographically patterned magnetic Co/Pd multilayer film plus bias fields. Rubidium atoms in the |F =1 , mF=-1 > low-field seeking state are trapped at estimated distances down to about 100 nm from the chip surface and with calculated mean trapping frequencies up to about 800 kHz . The measured lifetimes of the atoms trapped in the magnetic lattice are in the range 0.4-1.7 ms , depending on distance from the chip surface. Model calculations suggest the trap lifetimes are currently limited mainly by losses due to one-dimensional thermal evaporation following loading of the atoms from the Z -wire trap into the very tight magnetic lattice traps, rather than by fundamental loss processes such as surface interactions, three-body recombination, or spin flips due to Johnson magnetic noise. The trapping of atoms in a 0.7 -μ m -period magnetic lattice represents a significant step toward using magnetic lattices for quantum tunneling experiments and to simulate condensed matter and many-body phenomena in nontrivial lattice geometries.

  11. Bose-Einstein Condensation in an electro-pneumatically transformed quadrupole-Ioffe magnetic trap

    CERN Document Server

    Kumar, Sunil; Verma, Gunjan; Vishwakarma, Chetan; Noaman, Md; Rapol, Umakant

    2014-01-01

    We report a novel approach for preparing a Bose-Einstein condensate (BEC) of $^{87}$Rb atoms using electro-pneumatically driven transfer of atoms into a Quadrupole-Ioffe magnetic trap (QUIC Trap). More than 5$\\times$$10^{8}$ atoms from a Magneto-optical trap are loaded into a spherical quadrupole trap and then these atoms are transferred into an Ioffe trap by moving the Ioffe coil towards the center of the quadrupole coil, thereby, changing the distance between quadrupole trap center and the Ioffe coil. The transfer efficiency is more than 80 \\%. This approach is different from a conventional approach of loading the atoms into a QUIC trap wherein the spherical quadrupole trap is transformed into a QUIC trap by changing the currents in the quadrupole and the Ioffe coils. The phase space density is then increased by forced rf evaporative cooling to achieve the Bose-Einstein condensation having more than $10^{5}$ atoms.

  12. Magnetic trapping of neutral particles Classical and Quantum-mechanical study of a Ioffe-Pritchard type trap

    CERN Document Server

    Gov, S; Thomas, H

    1999-01-01

    Recently, we developed a method for calculating the lifetime of a particle inside a magnetic trap with respect to spin flips, as a first step in our efforts to understand the quantum-mechanics of magnetic traps. The 1D toy model that was used in this study was physically unrealistic because the magnetic field was not curl-free. Here, we study, both classically and quantum-mechanically, the problem of a neutral particle with spin S, mass m and magnetic moment mu, moving in 3D in an inhomogeneous magnetic field corresponding to traps of the Ioffe-Pritchard, `clover-leaf' and `baseball' type. Defining by omega_p, omega_z and omega_r the precessional, the axial and the lateral vibrational frequencies, respectively, of the particle in the adiabatic potential, we find classically the region in the $(ømega_{r}% (omega_r -- omega_z) plane where the particle is trapped. Quantum-mechanically, we study the problem of a spin-one particle in the same field. Treating omega_r / omega_p and omega_z / omega_p as small parame...

  13. Optically induced interaction of magnetic moments in hybrid metamaterials.

    Science.gov (United States)

    Miroshnichenko, Andrey E; Luk'yanchuk, Boris; Maier, Stefan A; Kivshar, Yuri S

    2012-01-24

    We propose a novel type of hybrid metal-dielectric structures composed of silicon nanoparticles and split-ring resonators for advanced control of optically induced magnetic response. We reveal that a hybrid "metamolecule" may exhibit a strong distance-dependent magnetic interaction that may flip the magnetization orientation and support "antiferromagnetic" ordering in a hybrid metamaterial created by a periodic lattice of such metamolecules. The propagation of magnetization waves in the hybrid structures opens new ways for manipulating artificial "antiferromagnetic" ordering at high frequencies. © 2011 American Chemical Society

  14. Quantum Simulation of Frustrated Magnetism with Many Trapped Ions

    Science.gov (United States)

    Senko, Crystal

    2013-05-01

    A collection of trapped atomic ions is an excellent system for simulating quantum many-body physics, like magnetism, which may be difficult to access via classical computation or traditional condensed-matter experiments. Our large crystals of 10-20 ions comprise a platform to study a long-range quantum Ising model with tunable couplings in a 1D spin chain. State-dependent optical dipole forces exploit the Coulomb interaction to generate the spin-spin couplings, and fluorescence measurements on a camera are used to read out individual spin states. We investigated the spin order resulting from changing the range of antiferromagnetic interactions or the strength of an axial magnetic field, demonstrating our control over the amount of frustration present. We are turning to the study of dynamics in this system, with the aim of exploring topics including adiabaticity, spectroscopy of the Hamiltonian, the emergence of Kibble-Zurek-like behavior in a finite system, thermalization in an isolated quantum system, and nonequilibrium phase transitions. There is great promise in extending the system to 30+ spins, where computations become classically intractable. Co-authors are R. Islam, P. Richerme, W. C. Campbell, S. Korenblit, J. Smith, A. Lee, E. E. Edwards, C.-C. J. Wang, J. K. Freericks, and C. Monroe. This work is supported by grants from the U.S. Army Research Office with funding from the DARPA OLE program, IARPA, and the MURI program; and the NSF Physics Frontier Center at JQI.

  15. Raman transitions between hyperfine clock states in a magnetic trap

    CERN Document Server

    Naber, J B; Hubert, T; Spreeuw, R J C

    2016-01-01

    We present our experimental investigation of an optical Raman transition between the magnetic clock states of $^{87}$Rb in an atom chip magnetic trap. The transfer of atomic population is induced by a pair of diode lasers which couple the two clock states off-resonantly to an intermediate state manifold. This transition is subject to destructive interference of two excitation paths, which leads to a reduction of the effective two-photon Rabi-frequency. Furthermore, we find that the transition frequency is highly sensitive to the intensity ratio of the diode lasers. Our results are well described in terms of light shifts in the multi-level structure of $^{87}$Rb. The differential light shifts vanish at an optimal intensity ratio, which we observe as a narrowing of the transition linewidth. We also observe the temporal dynamics of the population transfer and find good agreement with a model based on the system's master equation and a Gaussian laser beam profile. Finally, we identify several sources of decoheren...

  16. Accumulation and thermalization of cold atoms in a finite-depth magnetic trap

    CERN Document Server

    Chicireanu, R; Gorceix, O; Keller, J C; Laburthe-Tolra, B; Marechal, E; Porto, J V; Pouderous, A; Vernac, L

    2006-01-01

    We experimentally and theoretically study the continuous accumulation of cold atoms from a magneto-optical trap (MOT) into a finite depth trap, consisting in a magnetic quadrupole trap dressed by a radiofrequency (RF) field. Chromium atoms (52 isotope) in a MOT are continuously optically pumped by the MOT lasers to metastable dark states. In presence of a RF field, the temperature of the metastable atoms that remain magnetically trapped can be as low as 25 microK, with a density of 10^17 atoms.m-3, resulting in an increase of the phase-space density, still limited to 7.10^-6 by inelastic collisions. To investigate the thermalization issues in the truncated trap, we measure the free evaporation rate in the RF-truncated magnetic trap, and deduce the average elastic cross section for atoms in the 5D4 metastable states, equal to 7.0 10^-16m2.

  17. Improvement of persistent magnetic field trapping in bulk Y-Ba-Cu-O superconductors

    Science.gov (United States)

    Chen, In-Gann; Weinstein, Roy

    1993-01-01

    For type-II superconductors, magnetic field can be trapped due to persistent internal supercurrent. Quasi-persistent magnetic fields near 2 T at 60 K (and 1.4 T at 77 K) have been measured in minimagnets made of proton-irradiated melt-textured Y-Ba-Cu-O (MT-Y123) samples. Using the trapping effect, high-field permanent magnets with dipole, quadrupole, or more complicated configurations can be made of existing MT-Y123 material, thus bypassing the need for high-temperature superconductor (HTS) wires. A phenomenological current model has been developed to account for the trapped field intensity and profile in HTS samples. This model is also a guide to select directions of materials development to further improve field trapping properties. General properties such as magnetic field intensities, spatial distributions, stabilities, and temperature dependence of trapped field are discussed.

  18. Levitation performance of the magnetized bulk high-T{sub c} superconducting magnet with different trapped fields

    Energy Technology Data Exchange (ETDEWEB)

    Liu, W. [Applied Superconductivity Laboratory, Southwest Jiaotong University (ASCLab), Chengdu, Sichuan 610031 (China); State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); National Laboratory of Rail Transit, Chengdu, Sichuan 610031 (China); Wang, J.S., E-mail: tonny@mars.swjtu.edu.c [Applied Superconductivity Laboratory, Southwest Jiaotong University (ASCLab), Chengdu, Sichuan 610031 (China); National Laboratory of Rail Transit, Chengdu, Sichuan 610031 (China); Liao, X.L.; Zheng, S.J.; Ma, G.T.; Zheng, J. [Applied Superconductivity Laboratory, Southwest Jiaotong University (ASCLab), Chengdu, Sichuan 610031 (China); State Key Laboratory of Traction Power, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); National Laboratory of Rail Transit, Chengdu, Sichuan 610031 (China); Wang, S.Y. [Applied Superconductivity Laboratory, Southwest Jiaotong University (ASCLab), Chengdu, Sichuan 610031 (China); National Laboratory of Rail Transit, Chengdu, Sichuan 610031 (China)

    2011-03-15

    Research highlights: {yields} The different trapped fields bring entirely different levitation performance. {yields} The force relaxation characters is directly bound up with the trapped field. {yields} The higher trapped field not means better levitation performance. {yields} An profitable internal induced current configuration will benefit to suppress flux motion. - Abstract: To a high-T{sub c} superconducting (HTS) maglev system which needs large levitation force density, the magnetized bulk high-T{sub c} superconductor (HTSC) magnet is a good candidate because it can supply additional repulsive or attractive force above a permanent magnet guideway (PMG). Because the induced supercurrent within a magnetized bulk HTSC is the key parameter for the levitation performance, and it is sensitive to the magnetizing process and field, so the magnetized bulk HTSC magnets with different magnetizing processes had various levitation performances, not only the force magnitude, but also its force relaxation characteristics. Furthermore, the distribution and configuration of the induced supercurrent are also important factor to decide the levitation performance, especially the force relaxation characteristics. This article experimentally investigates the influences of different magnetizing processes and trapped fields on the levitation performance of a magnetized bulk HTSC magnet with smaller size than the magnetic inter-pole distance of PMG, and the obtained results are qualitatively analyzed by the Critical State Model. The test results and analyses of this article are useful for the suitable choice and optimal design of magnetized bulk HTSC magnets.

  19. Analysis and design of permanent magnet biased magnetic bearing based on hybrid factor

    Directory of Open Access Journals (Sweden)

    Jinji Sun

    2016-03-01

    Full Text Available In this article, hybrid factor is proposed for hybrid magnetic bearing. The hybrid factor is defined as the ratio of the force produced by the permanent magnet and the forces produced by the permanent magnet and current in hybrid magnetic bearing. It is deduced from a certain radial hybrid magnetic bearing using its important parameters such as the current stiffness and displacement stiffness at first and then the dynamic model of magnetically suspended rotor system is established. The relationship between structural parameters and control system parameters is analyzed based on the hybrid factor. Some influencing factors of hybrid factor in hybrid magnetic bearing, such as the size of the permanent magnet, length of air gap, and area of the stator poles, are analyzed in this article. It can be concluded that larger hybrid factor can be caused by the smaller power loss according to the definition of hybrid factor mentioned above. Meanwhile, the hybrid factor has a maximum value, which is related to control system parameters such as proportional factor expect for structural parameters. Finally, the design steps of parameters of hybrid magnetic bearing can be concluded.

  20. A dense gas of laser-cooled atoms for hybrid atom-ion trapping

    Science.gov (United States)

    Höltkemeier, Bastian; Glässel, Julian; López-Carrera, Henry; Weidemüller, Matthias

    2017-01-01

    We describe the realization of a dark spontaneous-force trap of rubidium atoms. The atoms are loaded from a beam provided by a two-dimensional magneto-optical trap yielding a capture efficiency of 75%. The dense and cold atomic sample is characterized by saturated absorption imaging. Up to 10^9 atoms are captured with a loading rate of 3× 10^9 atoms/s into a cloud at a temperature of 250 μK with the density exceeding 10^{11} atoms/cm^3. Under steady-state conditions, more than 90% of the atoms can be prepared into the absolute atomic ground state, which provides favorable conditions for the investigation of sympathetic cooling of ions in a hybrid atom-ion trap.

  1. Trapping a magnetic field of 7.9 T using a bulk magnet fabricated from stack of coated conductors

    Science.gov (United States)

    Tamegai, T.; Hirai, T.; Sun, Y.; Pyon, S.

    2016-11-01

    We have fabricated a bulk magnet using double stack, each 130 layers, of short segments of coated conductors (CCs). The bulk magnet is magnetized by field-cooling in a magnetic field of 9 T down to 4.2 K. After reducing the magnetic field down to zero, we have successfully trapped a magnetic field of 7.9 T at the centre of the double stack. The magnetic field profile of the bulk magnet is calculated by fully considering the Jc(B) characteristics of the short segment of the CC. The trapped magnetic field values measured by Hall probes at three locations near the centre of the double stacks agree reasonably well with the calculated magnetic induction.

  2. Maximum trapped field of a ring bulk superconductor by low pulsed field magnetization

    Energy Technology Data Exchange (ETDEWEB)

    Tsuchimoto, M. [Hokkaido Institute of Technology, 7-15 Maeda, Teine-ku, Sapporo 006-8585 (Japan)], E-mail: tsuchi@hit.ac.jp; Kamijo, H. [Railway Technical Research Institute, 2-8-38, Hikari-cho, Kokubunji, Tokyo 185-8540 (Japan)

    2007-10-01

    Pulsed field magnetization is an important technique for a bulk superconducting magnet, which is one practical application of a bulk high T{sub c} superconductor (HTS). Full magnetization of a ring HTS is effective to obtain large trapped field for low pulsed field magnetization. In this study, trapped field in a ring bulk superconductor by the low pulsed field magnetization is numerically analyzed under assumption of variable shielding current by the temperature control. Differences between one-dimensional Bean model and axisymmetric three-dimensional numerical solution are discussed through the analysis. There is maximum trapped field in the axisymmetric three-dimensional model because of finite thickness of the ring HTS. The shielding current density and inner radius of the ring HTS are discussed to obtain the maximum trapped field.

  3. Simulation of the magnetic field generated by wires with stationary current and magnets with constant magnetization applied to the mirror trap, minimum-B and zero-B

    Science.gov (United States)

    Murillo, M. T.; Otero, O.

    2016-02-01

    As a contribution to the computational simulation of magnetic confinement and heating of plasmas ECR (Electron Cyclotron Resonance), this work is dedicated to the calculation and subsequent analysis of the magnetic fields generated by permanent magnets and coils required in magnetic traps between which we can mention the mirror trap, minimum- B and zero-B. To do this, we solved numerically the Biot-Savart law in the case of the coils with stationary current and the Ampere law in the case of the permanent magnets. The study includes the characterization of the ECR areas as well as the display of the vector field all of this applied to the magnetic traps mentioned above. Additionally, in the case of the mirror type trap and minimum-B trap, it is determined the ratio of the mirror, because it is important in the description of confinement.

  4. Biomimetic and plasmonic hybrid light trapping for highly efficient ultrathin crystalline silicon solar cells.

    Science.gov (United States)

    Zhang, Y; Jia, B; Gu, M

    2016-03-21

    Designing effective light-trapping structures for the insufficiently absorbed long-wavelength light in ultrathin silicon solar cells represents a key challenge to achieve low cost and highly efficient solar cells. We propose a hybrid structure based on the biomimetic silicon moth-eye structure combined with Ag nanoparticles to achieve advanced light trapping in 2 μm thick crystalline silicon solar cells approaching the Yablonovitch limit. By synergistically using the Mie resonances of the silicon moth-eye structure and the plasmonic resonances of the Ag nanoparticles, the integrated absorption enhancement achieved across the usable solar spectrum is 69% compared with the cells with the conventional light trapping design. This is significantly larger than both the silicon moth-eye structure (58%) and Ag nanoparticle (41%) individual light trapping. The generated photocurrent in the 2 μm thick silicon layer is as large as 33.4 mA/cm2, which is equivalent to that generated by a 30 μm single-pass absorption in the silicon. The research paves the way for designing highly efficient light trapping structures in ultrathin silicon solar cells.

  5. Hybrid magnet project at Tohoku University

    Energy Technology Data Exchange (ETDEWEB)

    Nakagawa, Y.; Noto, K.; Hoshi, A.; Miura, S.; Watanabe, K.; Muto, Y. (Tohoku University (Japan))

    1984-01-01

    The construction of three hybrid magnets has been conceived in this project. The smallest one now in operation is composed of a non-cryostable NbTi coil weighing 270 kg and a Bitter coil with a power of 3.1 MW, producing 20 T field in a 32 mm diameter bore. The second one, 20 T in 52 mm at present, will produce 23 T when the power supply will be enlarged to 8 MW. The largest one, 31 T in 32 mm or 29 T in 52 mm, has been designed to consist of a multifilamentary Nb/sub 3/Sn + NbTi coil and a polyhelix-type water-cooled coil.

  6. Efficient Direct Evaporative Cooling in an Atom Chip Magnetic Trap

    CERN Document Server

    Farkas, Daniel M; Du, Shengwang; Anderson, Dana

    2013-01-01

    We demonstrate direct evaporative cooling of $^{87}$Rb atoms confined in a dimple trap produced by an atom chip. By changing the two chip currents and two external bias fields, we show theoretically that the trap depth can be lowered in a controlled way with no change in the trap frequencies or the value of the field at the trap center. Experimentally, we maximized the decrease in trap depth by allowing some loosening of the trap. In total, we reduced the trap depth by a factor of 20. The geometric mean of the trap frequencies was reduced by less than a factor of 6. The measured phase space density in the final two stages increased by more than two orders of magnitude, and we estimate an increase of four orders of magnitude over the entire sequence. A subsequent rf evaporative sweep of only a few megahertz produced Bose-Einstein condensates. We also produce condensates in which raising the trap bottom pushes hotter atoms into an rf "knife" operating at a fixed frequency of 5\\,MHz.

  7. Optimization of the Loading Process of the QUIC Magnetic Trap for the Experiment of Bose-Einstein Condensation

    Institute of Scientific and Technical Information of China (English)

    CHEN Shuai; ZHOU Xiao-Ji; YANG Fan; XIA Lin; WANG Yi-Qiu; CHEN Xu-Zong

    2004-01-01

    @@ The magnetic quadrupole-Ioffe configuration (QUIC) trap in our Bose-Einstein condensation experiment is introduced. The magnetic trap loading process after laser cooling is analysed and the optimization of the loading process is studied experimentally. Calculation of the magnetic field explains the loss of the atoms during the loading process of the QUIC trap. The number of atoms loaded in the QUIC trap is increased by 40%o after optimization in comparison with the normal loading process.

  8. Magnetic levitation for effective loading of cold cesium atoms in a crossed dipole trap

    Science.gov (United States)

    Li, Yuqing; Feng, Guosheng; Xu, Rundong; Wang, Xiaofeng; Wu, Jizhou; Chen, Gang; Dai, Xingcan; Ma, Jie; Xiao, Liantuan; Jia, Suotang

    2015-05-01

    We report a detailed study of effective magnetically levitated loading of cold atoms in a crossed dipole trap: an appropriate magnetic field gradient precisely compensates for the destructive gravitational force of the atoms and an additional bias field simultaneously eliminates the antitrapping potential induced by the magnetic field gradient. The magnetic levitation is required for a large-volume crossed dipole trap to form a shallow but very effective loading potential, making it a promising method for loading and trapping more cold atoms. For cold cesium atoms in the F =3 , m F =3 state prepared by three-dimensional degenerated Raman sideband cooling, a large number of atoms ˜3.2 ×106 have been loaded into a large-volume crossed dipole trap with the help of the magnetic levitation technique. The dependence of the number of atoms loaded and trapped in the dipole trap on the magnetic field gradient and bias field, respectively, is in good agreement with the theoretical analysis. The optimum magnetic field gradient of 31.13 G/cm matches the theoretical value of 31.3 G/cm well. This method can be used to obtain more cold atoms or a large number of Bose-Einstein condensation atoms for many atomic species in high-field seeking states.

  9. Magnetic trapping of superconducting submicron particles produced by laser ablation in superfluid helium

    Science.gov (United States)

    Takahashi, Yuta; Suzuki, Junpei; Yoneyama, Naoya; Tokawa, Yurina; Suzuki, Nobuaki; Matsushima, Fusakazu; Kumakura, Mitsutaka; Ashida, Masaaki; Moriwaki, Yoshiki

    2017-02-01

    We produced spherical superconducting submicron particles by laser ablation of their base metal tips in superfluid helium, and trapped them using a quadrupole magnetic field owing to the diamagnetism caused by the Meissner effect. We also measured their critical temperatures of superconductivity, by observing the threshold temperatures for the confinement of superconducting submicron particles in the trap.

  10. Hybrid Superconducting Magnetic Bearing (HSMB) for high load devices

    Science.gov (United States)

    McMichael, C. K.; Ma, K. B.; Lamb, M. A.; Lin, M. W.; Chow, L.; Meng, R. L.; Hor, P. H.; Chu, W. K.

    1992-05-01

    Lifting capacities greater than 41 N/cm(exp 2) (60 psi) at 77 K have been achieved with a new type of levitation (hybrid) using a combination of permanent magnets and high quality melt-mixtured YBa2Cu3O(7-delta) (YBCO). The key concept of the hybrid superconducting magnetic bearing (HSMB) is the use of strong magnetic repulsion and attraction from permanent magnets for high levitation or suspension forces in conjunction with a superconductor's flux pinning characteristics to counteract the inherent instabilities in a system consisting of magnets only. To illustrate this concept, radial and axial forces between magnet/superconductor, magnet/magnet, and magnet/superconductor/magnet, were measured and compared for the thrust bearing configuration

  11. Arrays of microscopic magnetic traps for cold atoms and their applications in atom optics

    Institute of Scientific and Technical Information of China (English)

    印建平; 高伟建; 胡建军

    2002-01-01

    A single microscopic magnetic trap for neutral atoms using planar current-carrying wires was proposed and studiedtheoretically by Weinstein et al. In this paper, we propose three structures of composite current-carrying wires to provide1D, 2D and 3D arrays of microscopic magnetic traps for cold alkali atoms. The spatial distributions of magnetic fieldsgenerated by these structures are calculated and the field gradient and curvature in each single microtrap are analysed.Our study shows that arrays of microscopic magnetic traps can be used to provide 1D, 2D or 3D atomic magneticlattices, and even to realize 1D, 2D and 3D arrays of magneto-optical traps, and so on.

  12. Mechanism of hybrid-magnetic-circuit multi-couple motor

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Discusses the interval between laminations in a permanent-magnet inductor motor which makes the air-gap magnetic field produced by the permanent magnet very uneven in the axial direction, and limits the performance of a motor. Proposes a hybrid-magnetic-circuit multi-couple motor to compensate for the uneven air-gap magnetic field, thereby improving the performance of a motor.

  13. REVIEWS OF TOPICAL PROBLEMS: On Galateas — magnetic traps with plasma-embedded conductors

    Science.gov (United States)

    Morozov, A. I.; Savel'ev, V. V.

    1998-11-01

    The introduction of plasma-embedded magnetically insulated current-carrying conductors into a plasma trap magnetic system radically increases the number of possible trap designs. The present review focuses on the studies of β = 1 Galateas conducted in the 1990s. Both general and design-specific Galatea properties are discussed and for a number of specific schemes analytical and numerical calculations are performed. Experimental data on a number of electrical discharge Galateas are presented.

  14. Design of Magnetic Flux Feedback Controller in Hybrid Suspension System

    Directory of Open Access Journals (Sweden)

    Wenqing Zhang

    2013-01-01

    Full Text Available Hybrid suspension system with permanent magnet and electromagnet consumes little power consumption and can realize larger suspension gap. But realizing stable suspension of hybrid magnet is a tricky problem in the suspension control sphere. Considering from this point, we take magnetic flux signal as a state variable and put this signal back to suspension control system. So we can get the hybrid suspension mathematical model based on magnetic flux signal feedback. By application of MIMO feedback linearization theory, we can further realize linearization of the hybrid suspension system. And then proportion, integral, differentiation, magnetic flux density B (PIDB controller is designed. Some hybrid suspension experiments have been done on CMS04 magnetic suspension bogie of National University of Defense Technology (NUDT in China. The experiments denote that the new hybrid suspension control algorithm based on magnetic flux signal feedback designed in this paper has more advantages than traditional position-current double cascade control algorithm. Obviously, the robustness and stability of hybrid suspension system have been enhanced.

  15. Controlled Flow Distortion in an Offset Diffuser using Hybrid Trapped Vorticity

    Science.gov (United States)

    Burrows, T. J.; Vukasinovic, B.; Glezer, A.

    2016-11-01

    Trapped vorticity concentration engendered by deliberate modification of the internal surface of an offset diffuser is coupled with a spanwise array of surface-integrated fluidic-oscillating jets for hybrid flow control of streamwise vorticity concentrations that dominate the base flow and give rise to flow distortions at the engine inlet. The local and global characteristics of the diffuser flow in the absence and presence of the actuation are investigated at Mach numbers up to M = 0.7, using surface oil-flow visualization and pressure distributions, and particle image velocimetry. It is shown that two sources of streamwise vorticity dominate the base flow distortion, namely, corner and a central pair of counter-rotating vortices. The present investigations demonstrate that the actuation affects the topology, strength and scale of the trapped vorticity and thereby its coupling to and interaction with the counter rotating streamwise vortices, where the central vortex pair becomes fully suppressed. As a result, the actuation significantly alters the evolution of the flow within the diffuser, and leads to significant suppression of pressure distortion at the engine inlet (by about 80%) at actuation level that is less than 0.7% of the diffuser's mass flow rate. These findings indicate the utility of hybrid trapped vorticity actuation for mitigating adverse effects of secondary vorticity concentrations formed by local separation and corner flows. Supported by ONR.

  16. Organic-inorganic hybrid polymer-encapsulated magnetic nanobead catalysts.

    Science.gov (United States)

    Arai, Takayoshi; Sato, Toru; Kanoh, Hirofumi; Kaneko, Katsumi; Oguma, Koichi; Yanagisawa, Akira

    2008-01-01

    A new strategy for the encapsulation of magnetic nanobeads was developed by using the in situ self-assembly of an organic-inorganic hybrid polymer. The hybrid polymer of {[Cu(bpy)(BF(4))(2)(H(2)O)(2)](bpy)}(n) (bpy=4,4'-bipyridine) was constructed on the surface of amino-functionalized magnetic beads and the resulting hybrid-polymer-encapsulated beads were utilized as catalysts for the oxidation of silyl enolates to provide the corresponding alpha-hydroxy carbonyl compounds in high yield. After the completion of the reaction, the catalyst was readily recovered by magnetic separation and the recovered catalyst could be reused several times. Because the current method did not require complicated procedures for incorporating the catalyst onto the magnetic beads, the preparation and the application of various other types of organic-inorganic hybrid-polymer-coated magnetic beads could be possible.

  17. Observation of single neutral atoms in a large-magnetic-gradient vapour-cell magneto-optical trap

    Institute of Scientific and Technical Information of China (English)

    Wang Jing; He Jun; Qiu Ying; Yang Bao-Dong; Zhao Jiang-Yan; Zhang Tian-Cai; Wang Jun-Min

    2008-01-01

    Single caesium atoms in a large-magnetic-gradient vapour-cell magneto-optical trap have been identified. The trapping of individual atoms is marked by the steps in fluorescence signal corresponding to the capture or loss of single atoms. The typical magnetic gradient is about 29 mT/cm, which evidently reduces the capture rate of magneto-optical trap.

  18. A magnetic trap for high-field seeking neutron spin states

    Directory of Open Access Journals (Sweden)

    Th. Brenner

    2015-02-01

    Full Text Available A first experimental demonstration of a new type of magnetic trap for ultra-cold neutrons is presented. High-field seeking spin-states are trapped in a potential formed by the magnetic field of a straight wire and a repulsive coating on the wire surface. Life-times of the trapped neutrons of 60 s could be observed. This configuration can in principle be used to form bound states of the wave function on the surface of the wire to probe new forces at short distances. Further applications include the use as a guide and selector for perfectly polarized neutrons.

  19. A magnetic trap for high-field seeking neutron spin states

    Energy Technology Data Exchange (ETDEWEB)

    Brenner, Th. [Institut Laue-Langevin, 38042 Grenoble Cedex 9 (France); Chesnevskaya, S. [Physik Department, Technische Universität München, D-85748 Garching (Germany); Fierlinger, P., E-mail: peter.fierlinger@tum.de [Physik Department, Technische Universität München, D-85748 Garching (Germany); Geltenbort, P. [Institut Laue-Langevin, 38042 Grenoble Cedex 9 (France); Gutsmiedl, E. [Physik Department, Technische Universität München, D-85748 Garching (Germany); Lauer, T. [Forschungsneutronenquelle Heinz Maier-Leibnitz, Technische Universität München, D-85748 Garching (Germany); Rezai, K. [University of California at Berkeley, CA 94720 (United States); Rothe, J. [Physik Department, Technische Universität München, D-85748 Garching (Germany); Zechlau, T. [Forschungsneutronenquelle Heinz Maier-Leibnitz, Technische Universität München, D-85748 Garching (Germany); Zou, R. [University of California at Berkeley, CA 94720 (United States)

    2015-02-04

    A first experimental demonstration of a new type of magnetic trap for ultra-cold neutrons is presented. High-field seeking spin-states are trapped in a potential formed by the magnetic field of a straight wire and a repulsive coating on the wire surface. Life-times of the trapped neutrons of 60 s could be observed. This configuration can in principle be used to form bound states of the wave function on the surface of the wire to probe new forces at short distances. Further applications include the use as a guide and selector for perfectly polarized neutrons.

  20. Plasma confinement time in trimix-M galatea multipole magnetic trap

    Science.gov (United States)

    Bishaev, A. M.; Bugrova, A. I.; Kozintseva, M. V.; Lipatov, A. S.; Sigov, A. S.; Kharchevnikov, V. K.

    2010-05-01

    The confinement time of hydrogen plasma trapped in a Trimix-M magnetic multipole galatea was studied in a range of plasma densities (1 × 1016 - 6 × 1018 m-3) and ion energies (˜100-300 eV). It is established that (i) the confinement time increases with decreasing plasma density in the trap and (ii) as the barrier magnetic field is increased, the plasma confinement time grows faster than according to a linear law. The obtained results are indicative of a collisional character of plasma diffusion through the barrier field in the trap.

  1. Light trapping in thin-film solar cells with randomly rough and hybrid textures.

    Science.gov (United States)

    Kowalczewski, Piotr; Liscidini, Marco; Andreani, Lucio Claudio

    2013-09-09

    We study light-trapping in thin-film silicon solar cells with rough interfaces. We consider solar cells made of different materials (c-Si and μc-Si) to investigate the role of size and nature (direct/indirect) of the energy band gap in light trapping. By means of rigorous calculations we demonstrate that the Lambertian Limit of absorption can be obtained in a structure with an optimized rough interface. We gain insight into the light trapping mechanisms by analysing the optical properties of rough interfaces in terms of Angular Intensity Distribution (AID) and haze. Finally, we show the benefits of merging ordered and disordered photonic structures for light trapping by studying a hybrid interface, which is a combination of a rough interface and a diffraction grating. This approach gives a significant absorption enhancement for a roughness with a modest size of spatial features, assuring good electrical properties of the interface. All the structures presented in this work are compatible with present-day technologies, giving recent progress in fabrication of thin monocrystalline silicon films and nanoimprint lithography.

  2. Negative thermal expansion in hybrid improper ferroelectric Ruddlesden-Popper perovskites by symmetry trapping.

    Science.gov (United States)

    Senn, M S; Bombardi, A; Murray, C A; Vecchini, C; Scherillo, A; Luo, X; Cheong, S W

    2015-01-23

    We present new results on the microscopic nature of the ferroelectricity mechanisms in Ca3 Mn2O7 and Ca3Ti2O7. To the first approximation, we confirm the hybrid improper ferroelectric mechanism recently proposed by Benedek and Fennie for these Ruddlesden-Popper compounds. However, in Ca3Mn2O7 we find that there is a complex competition between lattice modes of different symmetry which leads to a phase coexistence over a large temperature range and the "symmetry trapping" of a soft mode. This trapping of the soft mode leads to a large uniaxial negative thermal expansion (NTE) reaching a maximum between 250 and 350 K (3.6×10^(-6)  K^{-1}) representing the only sizable NTE reported for these and related perovskite materials to date. Our results suggest a systematic strategy for designing and searching for ceramics with large NTE coefficients.

  3. Hybrid Quantum System of a Nanofiber Mode Coupled to Two Chains of Optically Trapped Atoms

    CERN Document Server

    Zoubi, Hashem

    2010-01-01

    A tapered optical nanofiber simultaneously used to trap and optically interface of cold atoms through evanescent fields constitutes a new and well controllable hybrid quantum system. The atoms are trapped in two parallel 1D optical lattices generated by suitable far blue and red detuned evanescent field modes very close to opposite sides of the nanofiber surface. Collective electronic excitations (excitons) of each of the optical lattices are resonantly coupled to the second lattice forming symmetric and antisymmetric common excitons. In contrast to the inverse cube dependence of the individual atomic dipole-dipole interaction, we analytically find an exponentially decaying coupling strength with distance between the lattices. The resulting symmetric (bright) excitons strongly interact with the resonant nanofiber photons to form fiber polaritons, which can be observed through linear optical spectra. For large enough wave vectors the polariton decay rate to free space is strongly reduced, which should render t...

  4. Gap-related trapped magnetic flux dependence between single and combined bulk superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Z., E-mail: zgdeng@gmail.co [Laboratory of Applied Physics, Department of Marine Electronics and Mechanical Engineering, Tokyo University of Marine Science and Technology, Tokyo 135-8533 (Japan); Miki, M.; Felder, B.; Tsuzuki, K.; Shinohara, N.; Uetake, T.; Izumi, M. [Laboratory of Applied Physics, Department of Marine Electronics and Mechanical Engineering, Tokyo University of Marine Science and Technology, Tokyo 135-8533 (Japan)

    2011-05-15

    Highlights: {yields} Rectangular YBCO bulks to realize a compact combination. {yields} The gap effect was added to consider in the trapped flux density mapping. {yields} The trapped-flux dependence between single and combined bulks is gap related. {yields} It is possible to estimate the total magnetic flux of bulk combinations. - Abstract: Aiming at examining the trapped-flux dependence between single and combined bulk superconductors for field-pole applications, three rectangular Y{sub 1.65}Ba{sub 2}Cu{sub 3}O{sub 7-x} (YBCO) bulks with a possibly compact combination were employed to investigate the trapped-flux characteristics of single and combined bulks with a field-cooling magnetization (FCM) method. A gap-related dependence was found between them. At lower gaps of 1 mm and 5 mm, the peak trapped fields and total magnetic flux of combined bulks are both smaller than the additive values of each single bulk, which can be ascribed to the demagnetization influences of the field around the bulk generated by the adjacent ones. While, at larger gaps like 10 mm, the situation becomes reversed. The combined bulks can attain bigger peak trapped fields as well as total magnetic flux, which indicates that the magnetic field by the bulk combination can reach higher gaps, thanks to the bigger magnetic energy compared with the single bulk. The presented results show that, on one hand, it is possible to estimate the total trapped magnetic flux of combined bulks by an approximate additive method of each single bulk while considering a demagnetization factor; on the other hand, it also means that the performance of combined bulks will be superior to the addition of each single bulk at larger gaps, thus preferable for large-scaled magnet applications.

  5. Enhanced Magnetic Trap Loading and Coupled Optical Resonance Spectroscopy in Strontium

    Science.gov (United States)

    Barker, Daniel S.; Reschovsky, Benjamin J.; Pisenti, Neal C.; Campbell, Gretchen K.

    2015-05-01

    We investigate a technique to improve the loading of atomic strontium into a magnetic trap using a 688 nm de-pump laser on the 3P1 - 3S1 transition. Strontium degenerate gas experiments typically use a magnetic trap continuously loaded from a Magneto-Optical Trap (MOT) operating on the 461 nm line. A slow (~1:50,000) leak from the MOT transition populates the magnetically trapped 3P2 state and the 3P1 state in a 1:2 ratio. Pumping 3P1 atoms into 3P2 accelerates magnetic trap loading. For this purpose, we stabilize a 688 nm laser using Coupled Optical Resonance Laser Locking (COReLL) to the 679 nm, 688 nm, and 707 nm lines. The technique allows us to lock multiple lasers while only detecting absorption on the 707 nm transition. Error signals are generated with incommensurate frequency modulation of the pump beams. Preliminary application of the 688 nm laser to our 88Sr MOT results in 20% enhancement of magnetic trap atom number. We discuss the limitations of the loading rate enhancement and the potential for loading enhancement with other repumping strategies.

  6. The levitation characteristics of the magnetic substances using trapped HTS bulk annuli with various magnetic field distributions

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S.B., E-mail: kim@ec.okayama-u.ac.jp [Graduate School of Natural Science and Technology, Okayama University, 3-1-1, Tsushima-Naka, Kita-ku, Okayama 700-8530 (Japan); Ikegami, T.; Matsunaga, J.; Fujii, Y. [Graduate School of Natural Science and Technology, Okayama University, 3-1-1, Tsushima-Naka, Kita-ku, Okayama 700-8530 (Japan); Onodera, H. [Japan Science and Technology Agency–Core Research for Evolutional Science and Technology (JST–CREST), Tokyo 102-0076 (Japan)

    2013-11-15

    Highlights: •The spherical solenoid magnet can make a various magnetic field distributions. •We generated a large magnetic gradient at inner space of HTS bulks. •The levitation height of samples was improved by the reapplied field method. •The levitation height depends on the variation rate of magnetic field gradient. -- Abstract: We have been investigating the levitation system without any mechanical contact which is composed of a field-cooled ring-shaped high temperature superconducting (HTS) bulks [1]. In this proposed levitation system, the trapped magnetic field distributions of stacked HTS bulk are very important. In this paper, the spherical solenoid magnet composed of seven solenoid coils with different inner and outer diameters was designed and fabricated as a new magnetic source. The fabricated spherical solenoid magnet can easily make a homogeneous and various magnetic field distributions in inner space of stacked HTS bulk annuli by controlling the emerging currents of each coil. By using this spherical solenoid magnet, we tried to make a large magnetic field gradient in inner space of HTS bulk annuli, and it is very important on the levitation of magnetic substances. In order to improve the levitation properties of magnetic substances with various sizes, the external fields were reapplied to the initially trapped HTS bulk magnets. We could generate a large magnetic field gradient along the axial direction in inner space of HTS bulk annuli, and obtain the improved levitation height of samples by the proposed reapplied field method.

  7. Using injection molding and reversible bonding for easy fabrication of magnetic cell trapping and sorting devices

    Science.gov (United States)

    Royet, David; Hériveaux, Yoann; Marchalot, Julien; Scorretti, Riccardo; Dias, André; Dempsey, Nora M.; Bonfim, Marlio; Simonet, Pascal; Frénéa-Robin, Marie

    2017-04-01

    Magnetism and microfluidics are two key elements for the development of inexpensive and reliable tools dedicated to high-throughput biological analysis and providing a large panel of applications in domains ranging from fundamental biology to medical diagnostics. In this work, we introduce a simple protocol, relying on injection molding and reversible bonding for fabrication of magnetic cell trapping and sorting devices using only standard soft-lithography equipment. Magnetic strips or grids made of Polydimethylsiloxane (PDMS) doped with hard (NdFeB) or soft (carbonyl iron) magnetic powders were integrated at the bottom of whole PDMS chips. Preliminary results show the effective deviation/trapping of magnetic beads or magnetically-labeled bacteria as the sample flows through the microchannel, proving the potential of this rapid prototyping approach for easy fabrication of magnetic cell sorters.

  8. Preparation and characterization of functional silica hybrid magnetic nanoparticles

    Science.gov (United States)

    Digigow, Reinaldo G.; Dechézelles, Jean-François; Dietsch, Hervé; Geissbühler, Isabelle; Vanhecke, Dimitri; Geers, Christoph; Hirt, Ann M.; Rothen-Rutishauser, Barbara; Petri-Fink, Alke

    2014-08-01

    We report on the synthesis and characterization of functional silica hybrid magnetic nanoparticles (SHMNPs). The co-condensation of 3-aminopropyltriethoxysilane (APTES) and tetraethyl orthosilicate (TEOS) in presence of superparamagnetic iron oxide nanoparticles (SPIONs) leads to hybrid magnetic silica particles that are surface-functionalized with primary amino groups. In this work, a comprehensive synthetic study is carried out and completed by a detailed characterization of hybrid particles' size and morphology, surface properties, and magnetic responses using different techniques. Depending on the mass ratio of SPIONs and the two silanes (TEOS and APTES), we were able to adjust the number of surface amino groups and tune the magnetic properties of the superparamagnetic hybrid particles.

  9. Hybrid composites of xanthan and magnetic nanoparticles for cellular uptake.

    Science.gov (United States)

    Bueno, Vânia Blasques; Silva, Anielle Martins; Barbosa, Leandro Ramos Souza; Catalani, Luiz Henrique; Teixeira-Neto, Erico; Cornejo, Daniel Reinaldo; Petri, Denise Freitas Siqueira

    2013-11-04

    We describe a fast and simple method to prepare composite films of magnetite nanoparticles and xanthan networks. The particles are distributed close to hybrid film surface, generating a coercivity of 27 ± 2 Oe at 300 K. The proliferation of fibroblast cells on the hybrid composites was successful, particularly when an external magnetic field was applied.

  10. An integrated magnet array for trapping and manipulation of magnetotactic bacteria in microfluidics

    NARCIS (Netherlands)

    Hageman, T.A.G.; Pichel, M.P.; Altmeyer, M.O.; Manz, A.; Abelmann, L.

    2014-01-01

    We present a novel system for localized magnetic manipulation of magnetotactic bacteria in microfluidic systems. Where other methods require small conductive tracks directly below the sample, the new system consists of an array of permanent magnets switchable by a drive current to either trap or gui

  11. An integrated magnet array for trapping and manipulation of magnetotactic bacteria in microfluidics

    NARCIS (Netherlands)

    Hageman, Tijmen Antoon Geert; Pichel, Marc Philippe; Pichel, M.P.; Altmeyer, Matthias; Manz, A; Abelmann, Leon

    We present a novel system for localized magnetic manipulation of magnetotactic bacteria in microfluidic systems. Where other methods require small conductive tracks directly below the sample, the new system consists of an array of permanent magnets switchable by a drive current to either trap or

  12. The natural remanent magnetizations of the exeter volcanic traps (Permian, Europe)

    NARCIS (Netherlands)

    Zijderveld, J.D.A.

    1967-01-01

    The natural remanent magnetizations of 35 samples from five quarries in the Permian traps from the Exeter region were carefully examined. A considerable number of the samples contained a secondary magnetism, the intensity of which was directly proportional to the susceptibility. This secondary magne

  13. Design and performance of a cryogenic apparatus for magnetically trapping ultracold neutrons

    Science.gov (United States)

    Huffman, P. R.; Coakley, K. J.; Doyle, J. M.; Huffer, C. R.; Mumm, H. P.; O'Shaughnessy, C. M.; Schelhammer, K. W.; Seo, P.-N.; Yang, L.

    2014-11-01

    The cryogenic design and performance of an apparatus used to magnetically confine ultracold neutrons (UCN) is presented. The apparatus is part of an effort to measure the beta-decay lifetime of the free neutron and is comprised of a high-current superconducting magnetic trap that surrounds ∼21 l of isotopically pure 4He cooled to approximately 250 mK. A 0.89 nm neutron beam can enter the apparatus from one end of the magnetic trap and a light collection system allows visible light generated within the helium by decays to be transported to detectors at room temperature. Two cryocoolers are incorporated to reduce liquid helium consumption.

  14. Magnetic trap effect to restrict motion of self-powered tiny liquid metal motors

    Science.gov (United States)

    Tan, Si-Cong; Gui, Han; Yuan, Bin; Liu, Jing

    2015-08-01

    We reported a phenomenon that the magnetic field can make up a boundary to restrict motion of the aluminum powered liquid metal motor. For the droplet motors with diameter below 1 mm, such magnetic trap effect will be strong enough to bounce them off the boundary. We attributed the effect to the electromagnetic mechanism. Owing to the Lorentz force, the high magnetic field will break up the directional running of the motor. The more aluminum added in the metal droplet, the stronger the trap effect. This phenomenon suggests an important way to control behavior of the liquid metal motors.

  15. Effects of magnetization on fusion product trapping and secondary neutron spectra

    Energy Technology Data Exchange (ETDEWEB)

    Knapp, P. F.; Schmit, P. F.; Hansen, S. B.; Gomez, M. R.; Hahn, K. D.; Sinars, D. B.; Peterson, K. J.; Slutz, S. A.; Sefkow, A. B.; Awe, T. J.; Harding, E.; Jennings, C. A.; Desjarlais, M. P.; Chandler, G. A.; Cooper, G. W.; Cuneo, M. E.; Geissel, M.; Harvey-Thompson, A. J.; Porter, J. L.; Rochau, G. A. [Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States); and others

    2015-05-15

    By magnetizing the fusion fuel in inertial confinement fusion (ICF) systems, the required stagnation pressure and density can be relaxed dramatically. This happens because the magnetic field insulates the hot fuel from the cold pusher and traps the charged fusion burn products. This trapping allows the burn products to deposit their energy in the fuel, facilitating plasma self-heating. Here, we report on a comprehensive theory of this trapping in a cylindrical DD plasma magnetized with a purely axial magnetic field. Using this theory, we are able to show that the secondary fusion reactions can be used to infer the magnetic field-radius product, BR, during fusion burn. This parameter, not ρR, is the primary confinement parameter in magnetized ICF. Using this method, we analyze data from recent Magnetized Liner Inertial Fusion experiments conducted on the Z machine at Sandia National Laboratories. We show that in these experiments BR ≈ 0.34(+0.14/−0.06) MG · cm, a ∼ 14× increase in BR from the initial value, and confirming that the DD-fusion tritons are magnetized at stagnation. This is the first experimental verification of charged burn product magnetization facilitated by compression of an initial seed magnetic flux.

  16. Rotational characteristics in the resonance state of the HTSC-permanent magnet hybrid magnetic bearing

    Energy Technology Data Exchange (ETDEWEB)

    Morii, Y.; Sukedai, M. [Kansai University, 3-3-35 Yamate-cho, Suita, Osaka 564-8680 (Japan); Ohashi, S., E-mail: ohashi@kansai-u.ac.jp [Kansai University, 3-3-35 Yamate-cho, Suita, Osaka 564-8680 (Japan)

    2011-11-15

    The hybrid magnetic bearing has been developed. In the hybrid system, effect of the pinning force becomes smaller. Influence of the vibration and the gradient angle in the resonance state is large. The resonance frequency becomes small in the hybrid bearing system. The hybrid magnetic bearing using permanent magnets and the high-Tc bulk superconductor (HTSC) has been developed. Repulsive force of the permanent magnet is introduced to increase the load weight of the magnetic bearing. Effect of the hybrid system has been shown. In this paper, influence of the hybrid system on the dynamic characteristics of the rotor is studied. The rotational characteristics in the mechanical resonance state are studied, and the equivalent magnetic spring coefficient is estimated from the experimental results of the load weight. The resonance frequency is measured by the rotation experiments. The rotor achieves stable levitation even in the resonance state. In the hybrid system, effect of the pinning force becomes smaller than that of the lateral force generated by the repulsive force between the two permanent magnets at the smaller air gap. Thus influence of the lateral vibration and the gradient angle in the resonance state becomes larger at a smaller air gap. The equivalent magnetic spring coefficient becomes also small, and the resonance frequency becomes small in the hybrid bearing system.

  17. Two-Color Magneto-Optical Trap with Small Magnetic Field for Ytterbium

    CERN Document Server

    Kawasaki, Akio; Yu, QinQin; Vuletić, Vladan

    2015-01-01

    We report a two-color magneto-optical trap (MOT) for ytterbium atoms operating at a low magnetic field gradient down to 2 G/cm where a conventional MOT using the singlet transition (6s^2 1S0 -> 6s6p 1P1) is unable to trap atoms. By simultaneously applying laser light on both the broad-linewidth singlet transition and the narrow-linewidth triplet transition (6s^2 1S0 -> 6s6p 3P1), we load and trap 4.0 x 10^5 atoms directly from an atomic beam at 700 K. In the two-color MOT, the slowing and trapping functions are separately performed by the singlet transition light and the triplet transition light, respectively. The two-color MOT is highly robust against laser power imbalance even at very low magnetic field gradients.

  18. Deep cooling of optically trapped atoms implemented by magnetic levitation without transverse confinement

    Science.gov (United States)

    Li, Chen; Zhou, Tianwei; Zhai, Yueyang; Xiang, Jinggang; Luan, Tian; Huang, Qi; Yang, Shifeng; Xiong, Wei; Chen, Xuzong

    2017-05-01

    We report a setup for the deep cooling of atoms in an optical trap. The deep cooling is implemented by eliminating the influence of gravity using specially constructed magnetic coils. Compared to the conventional method of generating a magnetic levitating force, the lower trap frequency achieved in our setup provides a lower limit of temperature and more freedoms to Bose gases with a simpler solution. A final temperature as low as ˜ 6 nK is achieved in the optical trap, and the atomic density is decreased by nearly two orders of magnitude during the second stage of evaporative cooling. This deep cooling of optically trapped atoms holds promise for many applications, such as atomic interferometers, atomic gyroscopes, and magnetometers, as well as many basic scientific research directions, such as quantum simulations and atom optics.

  19. A micro-pillar array to trap magnetic beads in microfluidic systems

    KAUST Repository

    Gooneratne, Chinthaka Pasan

    2012-12-01

    A micro-pillar array (MPA) is proposed in this paper to trap and separate magnetic beads (MBs) in microfluidic systems. MBs are used in many biomedical applications due to being compatible in dimension to biomolecules, the large surface area available to attach biomolecules, and the fact that they can be controlled by a magnetic field. Trapping and separating these labeled biomolecules is an important step toward achieving reliable and accurate quantification for disease diagnostics. Nickel Iron (Ni50Fe 50) micro-pillars were fabricated on a Silicon (Si) substrate by standard microfabrication techniques. Experimental results showed that MBs could be trapped on the MPA at the single bead level and separated from other non-target particles. This principle can easily be extended to trap and separate target biomolecules in heterogeneous biological samples. © 2012 IEEE.

  20. Low-Energy Collective Excitation of Bose-Einstein Condensates in an Anisotropic Magnetic Trap

    Institute of Scientific and Technical Information of China (English)

    YANG Lu; WANG Xiao-Rui; LI Ke; TAN Xin-Zhou; XIONG Hong-Wei; LU Bao-Long

    2009-01-01

    We experimentally investigate the collective excitation of 87Rb Bose-Einstein condensates confined in a cigarshaped magnetic trap (QUIC trap).Using a method of magnetic perturbation,the center-of-mass oscillation of the condensate is excited, so that the radial trapping frequency of the QUIc trap can be precisely determined.A high-order excitation,characterized by a fast shape oscillation,also occurs simultaneously,with a noticeable damping in the oscillation ampfitude compared with the oscillation of the center ofmass.The measured oscillation frequencies,associated with these two low-energy exeiration modes.agree well with theoretical predictions based on the Gross-Pitaevskii equation.

  1. Trapping, anomalous transport and quasi-coherent structures in magnetically confined plasmas

    CERN Document Server

    Vlad, Madalina

    2009-01-01

    Strong electrostatic turbulence in magnetically confined plasmas is characterized by trapping or eddying of particle trajectories produced by the $E\\times B$ stochastic drift. Trapping is shown to produce strong effects on test particles and on test modes. It determines non-standard statistics of trajectories: non-Gaussian distribution, memory effects and coherence. Trapped trajectories form quasi-coherent structure. Trajectory trapping has strong nonlinear effects on the test modes on turbulent plasmas. We determine the growth rate of drift modes as function of the statistical characteristics of the background turbulence. We show that trapping provides the physical mechanism for the inverse cascade observed in drift turbulence and for the zonal flow generation.

  2. Trapped periosteum in a distal femoral physeal injury: magnetic resonance imaging evaluation

    Directory of Open Access Journals (Sweden)

    Marina Vimieiro Timponi de Moura

    2012-06-01

    Full Text Available Epiphyseal fractures are frequently associated with knee trauma during sports in children and adolescents. Usually, Salter-Harris types I and II fractures are conservatively treated. However, failed closed reduction of displaced fractures suggest the presence of trapped periosteum, with indication for surgery. The present report describes a case of Salter-Harris type I fracture of the distal femur in a child, complicated with trapped periosteum detected at magnetic resonance imaging.

  3. Hybrid Spintronic Structures With Magnetic Oxides and Heusler Alloys

    DEFF Research Database (Denmark)

    Xu, Y. B.; Hassan, S. S. A.; Wong, P. K. J.;

    2008-01-01

    Hybrid spintronic structures, integrating half-metallic magnetic oxides and Heusler alloys with their predicted high spin polarization, are important for the development of second-generation spintronics with high-efficient spin injection. We have synthesized epitaxial magnetic oxide Fe3O4 on GaAs...

  4. Formation of van der Waals molecules in buffer gas cooled magnetic traps

    CERN Document Server

    Brahms, N; Zhang, P; los, J K; Sadeghpour, H R; Dalgarno, A; Doyle, J M; Walker, T G

    2010-01-01

    We show that a large class of helium-containing cold polar molecules form readily in a cryogenic buffer gas, achieving densities as high as 10^12 cm^-3. We explore the spin relaxation of these molecules in buffer gas loaded magnetic traps, and identify a loss mechanism based on Landau-Zener transitions arising from the anisotropic hyperfine interaction. Our results show that the recently observed strong T^6 thermal dependence of spin change in buffer gas trapped silver (Ag) is accounted for by the formation and spin change of AgHe, thus providing evidence for molecular formation in a buffer gas trap.

  5. Trapped field measurements of Gd-Ba-Cu-O bulk superconductor in controlled pulse field magnetizing

    Energy Technology Data Exchange (ETDEWEB)

    Ida, T [Department of Electronic Control Engineering, Hiroshima National College of Maritime Technology, 4272-1, Higashino, Ohsakikamijima-cho, Toyota-gun, Hiroshima 725-0231 (Japan); Kimura, Y; Sano, T; Yamaguchi, K; Izumi, M [Department of Marine Electronics and Mechanical Engineering, Tokyo University of Marine Science and Technology, 2-1-6, Etchu-jima, Koto-ku, Tokyo 135-8533 (Japan); Miki, M [Kitano Seiki Co. Ltd., 7-13-7, Chuo, Ohta-ku, Tokyo 143-0024 (Japan)], E-mail: ida@hiroshima-cmt.ac.jp

    2008-02-01

    For large-scale electric power application of the melt-processed high temperature superconductor (HTS) bulks, especially at rotating machine, development of trapping much higher magnetic fields by using pulsed magnetization technique is essential. It is difficult to use static field cooling (FCM) technique that is most effective magnetizing method for the general industrial HTS applications, because the FCM requires large-scale superconducting magnets. Because the rise in temperature due to the magnetic flux motion decreases the pinning force, we controlled the magnetic flux penetrating to the bulk for the effective magnetization. A couple of vortex-type copper coils applied a magnetic field to a Gd-Ba-Cu-O bulk, which dimension was 45mm in diameter and 19 mm in thickness. HTS bulk was magnetized by the controlled pulse field without passive LCR pulse. We controlled waveform by using the discharge current that IGBT chopper in pulse magnetizer intermitted. We applied the pulse magnetic field with the various risetime to the HTS bulk in liquid nitrogen. The various conditions of the controlled waveform pulse to trap well-dressed profile magnetized the Gd-Ba-Cu-O bulk, strongly at 77K. In the present study, we show several properties which was measured in the PFM of the HTS bulk.

  6. Hybride magnetic nanostructure based on amino acids functionalized polypyrrole

    Science.gov (United States)

    Nan, Alexandrina; Bunge, Alexander; Turcu, Rodica

    2015-12-01

    Conducting polypyrrole is especially promising for many commercial applications because of its unique optical, electric, thermal and mechanical properties. We report the synthesis and characterization of novel pyrrole functionalized monomers and core-shell hybrid nanostructures, consisting of a conjugated polymer layer (amino acids functionalized pyrrole copolymers) and a magnetic nanoparticle core. For functionalization of the pyrrole monomer we used several amino acids: tryptophan, leucine, phenylalanine, serine and tyrosine. These amino acids were linked via different types of hydrophobic linkers to the nitrogen atom of the pyrrole monomer. The magnetic core-shell hybrid nanostructures are characterized by various methods such as FTIR spectroscopy, transmission electron microscopy (TEM) and magnetic measurements.

  7. Hybride magnetic nanostructure based on amino acids functionalized polypyrrole

    Energy Technology Data Exchange (ETDEWEB)

    Nan, Alexandrina, E-mail: alexandrina.nan@itim-cj.ro; Bunge, Alexander; Turcu, Rodica [National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat, 400293 Cluj-Napoca (Romania)

    2015-12-23

    Conducting polypyrrole is especially promising for many commercial applications because of its unique optical, electric, thermal and mechanical properties. We report the synthesis and characterization of novel pyrrole functionalized monomers and core-shell hybrid nanostructures, consisting of a conjugated polymer layer (amino acids functionalized pyrrole copolymers) and a magnetic nanoparticle core. For functionalization of the pyrrole monomer we used several amino acids: tryptophan, leucine, phenylalanine, serine and tyrosine. These amino acids were linked via different types of hydrophobic linkers to the nitrogen atom of the pyrrole monomer. The magnetic core-shell hybrid nanostructures are characterized by various methods such as FTIR spectroscopy, transmission electron microscopy (TEM) and magnetic measurements.

  8. Magnetic monopole search with the MoEDAL test trapping detector

    Directory of Open Access Journals (Sweden)

    Katre Akshay

    2016-01-01

    Full Text Available IMoEDAL is designed to search for monopoles produced in high-energy Large Hadron Collider (LHC collisions, based on two complementary techniques: nucleartrack detectors for high-ionisation signatures and other highly ionising avatars of new physics, and trapping volumes for direct magnetic charge measurements with a superconducting magnetometer. The MoEDAL test trapping detector array deployed in 2012, consisting of over 600 aluminium samples, was analysed and found to be consistent with zero trapped magnetic charge. Stopping acceptances are obtained from a simulation of monopole propagation in matter for a range of charges and masses, allowing to set modelindependent and model-dependent limits on monopole production cross sections. Multiples of the fundamental Dirac magnetic charge are probed for the first time at the LHC.

  9. Development of a 40 T compact hybrid magnet

    Energy Technology Data Exchange (ETDEWEB)

    Watanabe, K.; Awaji, S.; Kobayashi, N. [Tohoku Univ., Sendai (Japan). Inst. for Materials Research] [and others

    1996-07-01

    A 40 T compact hybrid magnet consisting of a 16 T outer superconducting magnet and a 24 T inner resistive magnet is conceptually designed. A highly strengthened superconducting magnet with a 360 mm room temperature bore can be made using newly developed (Nb,Ti){sub 3}Sn wires with Cu-Nb or Cu-Al{sub 2}O{sub 3} reinforcing stabilizer, and as a result the coil weight is outstandingly reduced by about 70%. A poly-Bitter resistive magnet which generates 24 T in a 14 mm room temperature bore is realized consuming 8 MW power.

  10. Stochastic modeling and survival analysis of marginally trapped neutrons for a magnetic trapping neutron lifetime experiment

    CERN Document Server

    Coakley, K J; M.,; Huber, G; P.,; Huffman, R; C.,; Huffer, R; Marley, D E; Mumm, H P; O'Shaughnessy, M; K.,; Schelhammer, W; Thompson, A K; Yue, A T

    2015-01-01

    In a variety of neutron lifetime experiments, in addition to $\\beta-$decay, neutrons can be lost by other mechanisms including wall losses. Failure to account for these other loss mechanisms produces systematic measurement error and associated systematic uncertainties in neutron lifetime measurements. In this work, we develop a physical model for neutron wall losses and construct a competing risks survival analysis model to account for losses due to the joint effect of $\\beta-$decay losses, wall losses of marginally trapped neutrons, and an additional absorption mechanism. We determine the survival probability function associated with the wall loss mechanism by a Monte Carlo method. Based on a fit of the competing risks model to a subset of the NIST experimental data, we determine the mean lifetime of trapped neutrons to be approximately 700 s -- considerably less than the current best estimate of (880.1 $\\pm$ 1.1) s promulgated by the Particle Data Group [1]. Currently, experimental studies are underway to d...

  11. Magnetic characterisation of large grain, bulk Y-Ba-Cu-O superconductor-soft ferromagnetic alloy hybrid structures

    Science.gov (United States)

    Philippe, M. P.; Fagnard, J.-F.; Kirsch, S.; Xu, Z.; Dennis, A. R.; Shi, Y.-H.; Cardwell, D. A.; Vanderheyden, B.; Vanderbemden, P.

    2014-07-01

    Large grain, bulk Y-Ba-Cu-O (YBCO) high temperature superconductors (HTS) have significant potential for use in a variety of practical applications that incorporate powerful quasi-permanent magnets. In the present work, we investigate how the trapped field of such magnets can be improved by combining bulk YBCO with a soft FeNi, ferromagnetic alloy. This involves machining the alloy into components of various shapes, such as cylinders and rings, which are attached subsequently to the top surface of a solid, bulk HTS cylinder. The effect of these modifications on the magnetic hysteresis curve and trapped field of the bulk superconductor at 77 K are then studied using pick-up coil and Hall probe measurements. The experimental data are compared to finite element modelling of the magnetic flux distribution using Campbell’s algorithm. Initially we establish the validity of the technique involving pick-up coils wrapped around the bulk superconductor to obtain its magnetic hysteresis curve in a non-destructive way and highlight the difference between the measured signal and the true magnetization of the sample. We then consider the properties of hybrid ferromagnet/superconductor (F/S) structures. Hall probe measurements, together with the results of the model, establish that flux lines curve outwards through the ferromagnet, which acts, effectively, like a magnetic short circuit. Magnetic hysteresis curves show that the effects of the superconductor and the ferromagnet simply add when the ferromagnet is saturated fully by the applied field. The trapped field of the hybrid structure is always larger than that of the superconductor alone below this saturation level, and especially when the applied field is removed. The results of the study show further that the beneficial effects on the trapped field are enhanced when the ferromagnet covers the entire surface of the superconductor for different ferromagnetic components of various shapes and fixed volume.

  12. Quench-induced trapping of magnetic flux in annular Josephson junctions

    DEFF Research Database (Denmark)

    Aarøe, Morten; Monaco, R.; Rivers, R.;

    2008-01-01

    over 4 orders of magnitude. After the quench the result of the spontaneous production of topological defects, trapped fluxons, is unambiguously observed as zero-field steps in the DC I-V characteristic of the junction. A power-law scaling behavior of trapping probability versus quench rate is found...... with a critical exponent of 0.5 (within experimental error). The main experimental challenges are to generate many identical quenches with accurate cooling rate, to automate data analysis and acquisition, and to suppress external magnetic fields and noise by passive magnetic shielding and compensation....

  13. Antimagnets: controlling magnetic fields with superconductor-metamaterial hybrids

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, Alvaro; Navau, Carles; Prat-Camps, Jordi; Chen Duxing, E-mail: alvar.sanchez@uab.cat [Grup d' Electromagnetisme, Departament de Fisica, Universitat Autonoma de Barcelona, 08193 Bellaterra, Barcelona, Catalonia (Spain)

    2011-09-15

    Magnetism is very important in various areas of science and technology, ranging from magnetic recording through energy generation to trapping cold atoms. Physicists have managed to master magnetism-to create and manipulate magnetic fields-almost at will. Surprisingly, there is at least one property that has been elusive until now: how to 'switch off' the magnetic interaction of a magnetic material with existing magnetic fields without modifying them. Here we introduce the antimagnet, a design that conceals the magnetic response of a given volume from its exterior, without altering the external magnetic fields, in some respects analogous to recent theoretical proposals for cloaking electromagnetic waves with metamaterials. However, unlike these devices, which require extreme material properties, our device is feasible and needs only two kinds of available materials: superconductors and isotropic magnetic materials. Antimagnets may have applications in magnetic-based medical techniques such as magnetic resonance imaging or in reducing the magnetic signature of vessels or planes.

  14. Characteristics of trapped magnetic fields in HTS bulk annuli with various axial spaces for compact NMR magnets

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S.B., E-mail: kim@elec.okayama-u.ac.j [Electrical and Electronic Engineering, Okayama University, 3-1-1, Tsushima Naka, Kita-ku, Okayama 700-8530 (Japan); Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139 (United States); Imai, M.; Takano, R.; Kashima, K.; Hahn, S. [Electrical and Electronic Engineering, Okayama University, 3-1-1, Tsushima Naka, Kita-ku, Okayama 700-8530 (Japan); Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, 170 Albany Street, Cambridge, MA 02139 (United States)

    2010-11-01

    Recently, the performance of high-temperature superconducting (HTS) bulks such as a critical current density, size, and mechanical strength has been improved. In consequence, various applications with HTS bulks such as motors, bearings, and flywheels are being investigated by many research groups; Compact nuclear magnetic resonance (NMR) magnet is one of the new applications after a technique to enhance maximum trapped field of an HTS bulk more than 11.7 T, 500 MHz {sup 1}H NMR frequency, has been developed. This new compact NMR magnet out of HTS bulks is far less expensive than those conventional NMR magnets and expected to be widely used in food and drug industry. In design and manufacture of those compact NMR magnets, the issues of spatial homogeneity and temporal stability of trapped magnetic fields in HTS bulk annuli are very important. In this paper, the characteristics of the trapped magnetic fields in a stack of assembled HTS bulk annuli were investigated with various axial spaces between HTS bulks, experimentally and analytically.

  15. Micro Penning Trap for Continuous Magnetic Field Monitoring in High Radiation Environments

    Science.gov (United States)

    Latorre, Javiera; Bollen, Georg; Gulyuz, Kerim; Ringle, Ryan; Bado, Philippe; Dugan, Mark; Lebit Team; Translume Collaboration

    2016-09-01

    As new facilities for rare isotope beams, like FRIB at MSU, are constructed, there is a need for new instrumentation to monitor magnetic fields in beam magnets that can withstand the higher radiation level. Currently NMR probes, the instruments used extensively to monitor magnetic fields, do not have a long lifespans in radiation-high environments. Therefore, a radiation-hard replacement is needed. We propose to use Penning trap mass spectrometry techniques to make high precision magnetic field measurements. Our Penning microtrap will be radiation resistant as all of the vital electronics will be at a safe distance from the radiation. The trap itself is made from materials not subject to radiation damage. Penning trap mass spectrometers can determine the magnetic field by measuring the cyclotron frequency of an ion with a known mass and charge. This principle is used on the Low Energy Beam Ion Trap (LEBIT) minitrap at NSCL which is the foundation for the microtrap. We have partnered with Translume, who specialize in glass micro-fabrication, to develop a microtrap in fused-silica glass. A microtrap is finished and ready for testing at NSCL with all of the electronic and hardware components setup. DOE Phase II SBIR Award No. DE-SC0011313, NSF Award Number 1062410 REU in Physics, NSF under Grant No. PHY-1102511.

  16. Tunable Magnetic Alignment between Trapped Exciton-Polariton Condensates

    Science.gov (United States)

    Ohadi, H.; del Valle-Inclan Redondo, Y.; Dreismann, A.; Rubo, Y. G.; Pinsker, F.; Tsintzos, S. I.; Hatzopoulos, Z.; Savvidis, P. G.; Baumberg, J. J.

    2016-03-01

    Tunable spin correlations are found to arise between two neighboring trapped exciton-polariton condensates which spin polarize spontaneously. We observe a crossover from an antiferromagnetic to a ferromagnetic pair state by reducing the coupling barrier in real time using control of the imprinted pattern of pump light. Fast optical switching of both condensates is then achieved by resonantly but weakly triggering only a single condensate. These effects can be explained as the competition between spin bifurcations and spin-preserving Josephson coupling between the two condensates, and open the way to polariton Bose-Hubbard ladders.

  17. Ultracold, radiative charge transfer in hybrid Yb ion - Rb atom traps

    CERN Document Server

    McLaughlin, B M; Lane, I C; McCann, J F

    2014-01-01

    Ultracold hybrid ion-atom traps offer the possibility of microscopic manipulation of quantum coherences in the gas using the ion as a probe. However, inelastic processes, particularly charge transfer can be a significant process of ion loss and has been measured experimentally for the Yb$^{+}$ ion immersed in a Rb vapour. We use first-principles quantum chemistry codes to obtain the potential energy curves and dipole moments for the lowest-lying energy states of this complex. Calculations for the radiative decay processes cross sections and rate coefficients are presented for the total decay processes. Comparing the semi-classical Langevin approximation with the quantum approach, we find it provides a very good estimate of the background at higher energies. The results demonstrate that radiative decay mechanisms are important over the energy and temperature region considered. In fact, the Langevin process of ion-atom collisions dominates cold ion-atom collisions. For spin dependent processes \\cite{kohl13} the...

  18. Designing dye-nanochannel antenna hybrid materials for light harvesting, transport and trapping.

    Science.gov (United States)

    Calzaferri, Gion; Méallet-Renault, Rachel; Brühwiler, Dominik; Pansu, Robert; Dolamic, Igor; Dienel, Thomas; Adler, Pauline; Li, Huanrong; Kunzmann, Andreas

    2011-02-25

    We discuss artificial photonic antenna systems that are built by incorporating chromophores into one-dimensional nanochannel materials and by organizing the latter in specific ways. Zeolite L (ZL) is an excellent host for the supramolecular organization of different kinds of molecules and complexes. The range of possibilities for filling its one-dimensional channels with suitable guests has been shown to be much larger than one might expect. Geometrical constraints imposed by the host structure lead to supramolecular organization of the guests in the channels. The arrangement of dyes inside the ZL channels is what we call the first stage of organization. It allows light harvesting within the volume of a dye-loaded ZL crystal and also the radiationless transport of energy to either the channel ends or center. One-dimensional FRET transport can be realized in these guest-host materials. The second stage of organization is realized by coupling either an external acceptor or donor stopcock fluorophore at the ends of the ZL channels, which can then trap or inject electronic excitation energy. The third stage of organization is obtained by interfacing the material to an external device via a stopcock intermediate. A possibility to achieve higher levels of organization is by controlled assembly of the host into ordered structures and preparation of monodirectional materials. The usually strong light scattering of ZL can be suppressed by refractive-index matching and avoidance of microphase separation in hybrid polymer/dye-ZL materials. The concepts are illustrated and discussed in detail on a bidirectional dye antenna system. Experimental results of two materials with a donor-to-acceptor ratio of 33:1 and 52:1, respectively, and a three-dye system illustrate the validity and challenges of this approach for synthesizing dye-nanochannel hybrid materials for light harvesting, transport, and trapping.

  19. CSEM-Steel hybrid wiggler/undulator magnetic field studies

    Energy Technology Data Exchange (ETDEWEB)

    Halbach, K.; Hoyer, E.; Marks, S.; Plate, D.; Shuman, D.

    1985-06-01

    Current design of permanent magnet wiggler/undulators use either pure charge sheet equivalent material (CSEM) or the CSEM-Steel hybrid configuration. Hybrid configurations offer higher field strength at small gaps, field distributions dominated by the pole surfaces and pole tuning. Nominal performance of the hybrid is generally predicted using a 2-D magnetic design code neglecting transverse geometry. Magnetic measurements are presented showing transverse configuration influence on performance, from a combination of models using CSEMs, REC (H/sub c/ = 9.2 KOe) and NdFe (H/sub c/ = 10.7 kOe), different pole widths and end configurations. Results show peak field improvement using NdFe in place of REC in identical models, gap peak field decrease with pole width decrease (all results less than computed 2-D fields), transverse gap field distributions, and importance of CSEM material overhanging the poles in the transverse direction for highest gap fields. 3 refs., 6 figs.

  20. Injection of electron beam into a toroidal trap using chaotic orbits near magnetic null.

    Science.gov (United States)

    Nakashima, C; Yoshida, Z; Himura, H; Fukao, M; Morikawa, J; Saitoh, H

    2002-03-01

    Injection of charged particle beam into a toroidal magnetic trap enables a variety of interesting experiments on non-neutral plasmas. Stationary radial electric field has been produced in a toroidal geometry by injecting electrons continuously. When an electron gun is placed near an X point of magnetic separatrix, the electron beam spreads efficiently through chaotic orbits, and electrons distribute densely in the torus. The current returning back to the gun can be minimized less than 1% of the total emission.

  1. Scanning instrumentation for measuring magnetic field trapping in high Tc superconductors

    Science.gov (United States)

    Sisk, R. C.; Helton, A. J.

    1993-01-01

    Computerized scanning instrumentation measures and displays trapped magnetic fields across the surface of high Tc superconductors at 77 K. Data are acquired in the form of a raster scan image utilizing stepping motor stages for positioning and a cryogenic Hall probe for magnetic field readout. Flat areas up to 45 mm in diameter are scanned with 0.5-mm resolution and displayed as false color images.

  2. FAST TRACK COMMUNICATION: Production of antihydrogen at reduced magnetic field for anti-atom trapping

    Science.gov (United States)

    Andresen, G. B.; Bertsche, W.; Boston, A.; Bowe, P. D.; Cesar, C. L.; Chapman, S.; Charlton, M.; Chartier, M.; Deutsch, A.; Fajans, J.; Fujiwara, M. C.; Funakoshi, R.; Gill, D. R.; Gomberoff, K.; Hangst, J. S.; Hayano, R. S.; Hydomako, R.; Jenkins, M. J.; Jørgensen, L. V.; Kurchaninov, L.; Madsen, N.; Nolan, P.; Olchanski, K.; Olin, A.; Page, R. D.; Povilus, A.; Robicheaux, F.; Sarid, E.; Silveira, D. M.; Storey, J. W.; Thompson, R. I.; van der Werf, D. P.; Wurtele, J. S.; Yamazaki, Y.

    2008-01-01

    We have demonstrated production of antihydrogen in a 1 T solenoidal magnetic field. This field strength is significantly smaller than that used in the first generation experiments ATHENA (3 T) and ATRAP (5 T). The motivation for using a smaller magnetic field is to facilitate trapping of antihydrogen atoms in a neutral atom trap surrounding the production region. We report the results of measurements with the Antihydrogen Laser PHysics Apparatus (ALPHA) device, which can capture and cool antiprotons at 3 T, and then mix the antiprotons with positrons at 1 T. We infer antihydrogen production from the time structure of antiproton annihilations during mixing, using mixing with heated positrons as the null experiment, as demonstrated in ATHENA. Implications for antihydrogen trapping are discussed.

  3. Production of antihydrogen at reduced magnetic field for anti-atom trapping

    CERN Document Server

    Andresen, G B; Boston, A; Bowe, P D; Cesar, C L; Chapman, S; Charlton, M; Chartier, M; Deutsch, A; Fajans, J; Fujiwara, M C; Funakoshi, R; Gill, D R; Gomberoff, K; Hangst, J S; Hayano, R S; Hydomako, R; Jenkins, M J; Jørgensen, L V; Kurchaninov, L; Madsen, N; Nolan, P; Olchanski, K; Olin, A; Page, R D; Povilus, A; Robicheaux, F; Sarid, E; Silveira, D M; Storey, J W; Thompson, R I; van der Werf, D P; Wurtele, J S; Yamazaki, Y

    2008-01-01

    We have demonstrated production of antihydrogen in a 1$,$T solenoidal magnetic field. This field strength is significantly smaller than that used in the first generation experiments ATHENA (3$,$T) and ATRAP (5$,$T). The motivation for using a smaller magnetic field is to facilitate trapping of antihydrogen atoms in a neutral atom trap surrounding the production region. We report the results of measurements with the ALPHA (Antihydrogen Laser PHysics Apparatus) device, which can capture and cool antiprotons at 3$,$T, and then mix the antiprotons with positrons at 1$,$T. We infer antihydrogen production from the time structure of antiproton annihilations during mixing, using mixing with heated positrons as the null experiment, as demonstrated in ATHENA. Implications for antihydrogen trapping are discussed.

  4. Design and resistive inserts for NHMFL 45-T hybrid magnet

    Energy Technology Data Exchange (ETDEWEB)

    Bird, M.D.; Bole, S.; Eyssa, Y.M.; Gao, B.J.; Zhang, H.; Schneider-Muntau, H.J. [National High Magnetic Field Lab., Tallahassee, FL (United States)

    1994-07-01

    The authors present conceptual designs for 24--27 MW hybrid magnet inserts generating more than 31 T in a warm bore of 32 mm to be installed at the new National High Magnetic Field Laboratory (NHMFL). The insert housing is designed to accommodate both axially and radially cooled magnets although here they only present axially cooled designs. The magnet coils are radially partitioned (poly-Bitter) to provide high fields at moderate stress and cooling levels. GlidCop, Cu-Be and Cu-Ag conductors are considered providing resistive fields at high as 34 T in a background field of 14 T.

  5. Thermal properties of a large-bore cryocooled 10 T superconducting magnet for a hybrid magnet

    Energy Technology Data Exchange (ETDEWEB)

    Ishizuka, M., E-mail: Mas_Ishizuka@shi.co.j [Graduate School of Engineering, Tohoku University, 6-6 Aramaki Aza Aoba, Aoba-ku, Sendai 980-8579 (Japan); Research and Development Center, Sumitomo Heavy Industries, Ltd., 19 Natsushima-chou, Yokosuka, Kanagawa 237-8555 (Japan); Hamajima, T. [Graduate School of Engineering, Tohoku University, 6-6 Aramaki Aza Aoba, Aoba-ku, Sendai 980-8579 (Japan); Itou, T. [Ehime Works, Sumitomo Heavy Industries, Ltd., 5-2 Soubiraki-cho, Niihama, Ehime 792-8588 (Japan); Sakuraba, J. [Research and Development Center, Sumitomo Heavy Industries, Ltd., 19 Natsushima-chou, Yokosuka, Kanagawa 237-8555 (Japan); Nishijima, G.; Awaji, S.; Watanabe, K. [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan)

    2010-11-01

    A cryocooled 10 T superconducting magnet with a 360 mm room temperature bore has been developed for a hybrid magnet. The superconducting magnet cooled by four Gifford-McMahon cryocoolers has been designed to generate a magnetic field of 10 T. Since superconducting wires composed of coils were subjected to large hoop stress over 150 MPa and Nb{sub 3}Sn superconducting wires particularly showed a low mechanical strength due to those brittle property, Nb{sub 3}Sn wires strengthened by NbTi-filaments were developed for the cryocooled superconducting magnet. We have already reported that the hybrid magnet could generate the resultant magnetic field of 27.5 T by adding 8.5 T from the superconducting magnet and 19 T from a water-cooled Bitter resistive magnet, after the water-cooled resistive magnet was inserted into the 360 mm room temperature bore of the cryocooled superconducting magnet. When the hybrid magnet generated the field of 27.5 T, it achieved the high magnetic-force field (B x {partial_derivative}Bz/{partial_derivative}z) of 4500 T{sup 2}/m, which was useful for magneto-science in high fields such as materials levitation research. In this paper, we particularly focus on the cause that the cryocooled superconducting magnet was limited to generate the designed magnetic field of 10 T in the hybrid magnet operation. As a result, it was found that there existed mainly two causes as the limitation of the magnetic field generation. One was a decrease of thermal conductive passes due to exfoliation from the coil bobbin of the cooling flange. The other was large AC loss due to both a thick Nb{sub 3}Sn layer and its large diameter formed on Nb-barrier component in Nb{sub 3}Sn wires.

  6. Phase Space Diagnostics of Trapped Atoms By Magnetic Ground-State Manipulation

    Science.gov (United States)

    Cahn, S. B.; Kumarakrishnan, A.; Shim, U.; Sleator, T.

    1997-04-01

    The in-situ measurement of the phase space distribution of atoms in a trap is important in the study of both ordinary and Bose-condensed matter. The current techniques for measuring the density distribution involve imaging the light emitted by atoms in the trap, time-of-flight measurement of the atoms as they fall through a sheet of light(C.D. Wallace, et al, JOSA B,11),703 (1994), resonant absorption imaging of the cloud(J.R. Ensher, et al, PRL 77), 4984 (1996), or off-resonant dispersive imaging. The first two techniques are in general use for imaging magneto-optical traps (MOTs) and the second two for Bose condensates. Velocity information is obtained indirectly by recording the expansion of the trap at different times following shut-off. By exploiting the magnetic field dependence of ground-state magnetic sublevel coherences, we have employed two techniques, MGE and MGFID(B. Dubetsky and P.R. Berman, Appl. Phys. B, 59), 147 (1994), to obtain atomic spatial information. This variant of atomic beam magnetic imaging(J.E. Thomas and L.J. Wang, Physics Reports 262), 311-366 (1995) also yields correlated position-velocity information by appropriate orientation of the applied magnetic field, as the detuning of the atom depends on both its position and velocity. Initial studies have given the velocity distribution and size of the MOT, and future experiments to measure correlations are proposed.

  7. The decay properties of the trapped magnetic field in HTS bulk superconducting actuator by AC controlled magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Kim, S.B. [Department of Electrical and Electronic Engineering, Okayama University, 3-1-1, Tsushima Naka, Okayama 700-8530 (Japan); Uwani, Y., E-mail: gen422310@s.okayama-u.ac.jp [Department of Electrical and Electronic Engineering, Okayama University, 3-1-1, Tsushima Naka, Okayama 700-8530 (Japan); Joo, J.H.; Kawamoto, R. [Department of Electrical and Electronic Engineering, Okayama University, 3-1-1, Tsushima Naka, Okayama 700-8530 (Japan); Jo, Y.S. [Center for Applied Superconductivity Technology, Korea Electrotechnology Research Institute, Seongju-dong, Changwon 641-120 (Korea, Republic of)

    2011-11-15

    The electric device applications of a high temperature superconducting (HTS) bulk magnet, having stable levitation and suspension properties according to their strong flux pinning force, have been proposed and developed. We have been investigating a three-dimensional (3-D) superconducting actuator using HTS bulks to develop a non-contract transportation device which moves freely in space. It is certain for our proposed 3-D superconducting actuator to be useful as a transporter used in a clean room where silicon wafers, which do not like mechanical contact and dust, are manufactured. The proposed actuator consists of the trapped HTS bulk as a mover and two-dimensionally arranged electromagnets as a stator. Up to now, the electromagnets consisted with iron core and copper coil were used as a stator, and each electromagnet was individually controlled using DC power supplies. In our previous work, the unstable movement characteristics of HTS bulk were observed under the DC operation, and the AC electromagnets driven with AC controlled current was proposed to solve these problems. In general, the trapped magnetic field in HTS bulk was decayed by a time-varying external magnetic field. Thus, it needs to optimize the shapes of AC electromagnets and operating patterns, the decay properties of the trapped magnetic field in the HTS bulk mover by the AC magnetic field should be cleared. In this paper, the influences of the frequency, the overall operating time, the strength of magnetization field and drive current against the decay of trapped magnetic field were experimentally studied using the fabricated AC electromagnets.

  8. Enhanced trapped field performance of bulk high-temperature superconductors using split coil, pulsed field magnetization with an iron yoke

    Science.gov (United States)

    Ainslie, M. D.; Fujishiro, H.; Mochizuki, H.; Takahashi, K.; Shi, Y.-H.; Namburi, D. K.; Zou, J.; Zhou, D.; Dennis, A. R.; Cardwell, D. A.

    2016-07-01

    Investigating and predicting the magnetization of bulk superconducting materials and developing practical magnetizing techniques is crucial to using them as trapped field magnets in engineering applications. The pulsed field magnetization (PFM) technique is considered to be a compact, mobile and relative inexpensive way to magnetize bulk samples, requiring shorter magnetization times (on the order of milliseconds) and a smaller and less complicated magnetization fixture; however, the trapped field produced by PFM is generally much smaller than that of slower zero field cooling or field cooling techniques, particularly at lower operating temperatures. In this paper, the PFM of two, standard Ag-containing Gd-Ba-Cu-O samples is carried out using two types of magnetizing coils: (1) a solenoid coil, and (2) a split coil, both of which make use of an iron yoke to enhance the trapped magnetic field. It is shown that a significantly higher trapped field can be achieved using a split coil with an iron yoke, and in order to explain these how this arrangement works in detail, numerical simulations using a 2D axisymmetric finite element method based on the H -formulation are carried to qualitatively reproduce and analyze the magnetization process from both electromagnetic and thermal points of view. It is observed that after the pulse peak significantly less flux exits the bulk when the iron core is present, resulting in a higher peak trapped field, as well as more overall trapped flux, after the magnetization process is complete. The results have important implications for practical applications of bulk superconductors as such a split coil arrangement with an iron yoke could be incorporated into the design of a portable, high magnetic field source/magnet to enhance the available magnetic field or in an axial gap-type bulk superconducting electric machine, where iron can be incorporated into the stator windings to (1) improve the trapped field from the magnetization process

  9. Single axis controlled hybrid magnetic bearing for left ventricular assist device: hybrid core and closed magnetic circuit.

    Science.gov (United States)

    da Silva, Isaias; Horikawa, Oswaldo; Cardoso, Jose R; Camargo, Fernando A; Andrade, Aron J P; Bock, Eduardo G P

    2011-05-01

    In previous studies, we presented main strategies for suspending the rotor of a mixed-flow type (centrifugal and axial) ventricular assist device (VAD), originally presented by the Institute Dante Pazzanese of Cardiology (IDPC), Brazil. Magnetic suspension is achieved by the use of a magnetic bearing architecture in which the active control is executed in only one degree of freedom, in the axial direction of the rotor. Remaining degrees of freedom, excepting the rotation, are restricted only by the attraction force between pairs of permanent magnets. This study is part of a joint project in development by IDPC and Escola Politecnica of São Paulo University, Brazil. This article shows advances in that project, presenting two promising solutions for magnetic bearings. One solution uses hybrid cores as electromagnetic actuators, that is, cores that combine iron and permanent magnets. The other solution uses actuators, also of hybrid type, but with the magnetic circuit closed by an iron core. After preliminary analysis, a pump prototype has been developed for each solution and has been tested. For each prototype, a brushless DC motor has been developed as the rotor driver. Each solution was evaluated by in vitro experiments and guidelines are extracted for future improvements. Tests have shown good results and demonstrated that one solution is not isolated from the other. One complements the other for the development of a single-axis-controlled, hybrid-type magnetic bearing for a mixed-flow type VAD.

  10. Hybrid high gradient permanent magnet quadrupole

    Science.gov (United States)

    N'gotta, P.; Le Bec, G.; Chavanne, J.

    2016-12-01

    This paper presents an innovative compact permanent magnet quadrupole with a strong gradient for potential use in future light source lattices. Its magnetic structure includes simple mechanical parts, rectangular permanent magnet blocks and soft iron poles. It has a wide aperture in the horizontal plane to accommodate an x-ray beam port, a common constraint in storage ring-based light sources. This specificity introduces field quality deterioration because of the resulting truncation of the poles; a suitable field quality can be restored with an optimized pole shape. A 82 T /m prototype with a bore radius of 12 mm and a 10 mm vertical gap between poles has been constructed and magnetically characterized. Gradient inhomogeneities better than 10-3 in the good field region were obtained after the installation of special shims.

  11. Universal nonmonotonic structure in the saturation curves of magneto-optical-trap-loaded Na+ ions stored in an ion-neutral hybrid trap: Prediction and observation

    Science.gov (United States)

    Blümel, R.; Wells, J. E.; Goodman, D. S.; Kwolek, J. M.; Smith, W. W.

    2015-12-01

    We predict that the maximal, steady-state ion capacity Ns(λ ) of radio-frequency (rf) traps, loaded at a rate of λ particles per rf cycle, shows universal, nonlinear, nonmonotonic behavior as a function of loading rate λ . The shape of Ns(λ ) , characterized by four dynamical regimes, is universal; i.e., it is predicted to manifest itself in all types of rf traps independent of the details of their construction and independent of particle species loaded. For λ ≪ 1 (region I), as expected, Ns(λ ) increases monotonically with λ . However, contrary to intuition, at intermediate λ ˜1 (region II), Ns(λ ) reaches a maximum, followed by a local minimum of Ns(λ ) (region III). For λ ≫1 (region IV), Ns(λ ) again rises monotonically. In region IV, numerical simulations, analytical calculations, and experiments show Ns(λ ) ˜λ2 /3 . We confirm our predictions both experimentally with magneto-optical-trap-loaded Na+ ions stored in a hybrid ion-neutral trap and numerically with the help of detailed ab initio molecular-dynamics simulations.

  12. Rotational characteristics in the resonance state of the HTSC-permanent magnet hybrid magnetic bearing

    Science.gov (United States)

    Morii, Y.; Sukedai, M.; Ohashi, S.

    2011-11-01

    The hybrid magnetic bearing using permanent magnets and the high-Tc bulk superconductor (HTSC) has been developed. Repulsive force of the permanent magnet is introduced to increase the load weight of the magnetic bearing. Effect of the hybrid system has been shown. In this paper, influence of the hybrid system on the dynamic characteristics of the rotor is studied. The rotational characteristics in the mechanical resonance state are studied, and the equivalent magnetic spring coefficient is estimated from the experimental results of the load weight. The resonance frequency is measured by the rotation experiments. The rotor achieves stable levitation even in the resonance state. In the hybrid system, effect of the pinning force becomes smaller than that of the lateral force generated by the repulsive force between the two permanent magnets at the smaller air gap. Thus influence of the lateral vibration and the gradient angle in the resonance state becomes larger at a smaller air gap. The equivalent magnetic spring coefficient becomes also small, and the resonance frequency becomes small in the hybrid bearing system.

  13. Superconducting and hybrid systems for magnetic field shielding

    Science.gov (United States)

    Gozzelino, L.; Gerbaldo, R.; Ghigo, G.; Laviano, F.; Truccato, M.; Agostino, A.

    2016-03-01

    In this paper we investigate and compare the shielding properties of superconducting and hybrid superconducting/ferromagnetic systems, consisting of cylindrical cups with an aspect ratio of height/radius close to unity. First, we reproduced, by finite-element calculations, the induction magnetic field values measured along the symmetry axis in a superconducting (MgB2) and in a hybrid configuration (MgB2/Fe) as a function of the applied magnetic field and of the position. The calculations are carried out using the vector potential formalism, taking into account simultaneously the non-linear properties of both the superconducting and the ferromagnetic material. On the basis of the good agreement between the experimental and the computed data we apply the same model to study the influence of the geometric parameters of the ferromagnetic cup as well as of the thickness of the lateral gap between the two cups on the shielding properties of the superconducting cup. The results show that in the considered non-ideal geometry, where the edge effect in the flux penetration cannot be disregarded, the superconducting shield is always the most efficient solution at low magnetic fields. However, a partial recovery of the shielding capability of the hybrid configuration occurs if a mismatch in the open edges of the two cups is considered. In contrast, at high magnetic fields the hybrid configurations are always the most effective. In particular, the highest shielding factor was found for solutions with the ferromagnetic cup protruding over the superconducting one.

  14. Influence of the magnetic field expansion on the core plasma in an axisymmetric mirror trap

    Science.gov (United States)

    Soldatkina, E.; Anikeev, M.; Bagryansky, P.; Korzhavina, M.; Maximov, V.; Savkin, V.; Yakovlev, D.; Yushmanov, P.; Dunaevsky, A.

    2017-02-01

    First measurements of plasma parameters in an expander of a mirror trap with sub-fusion plasma parameters are reported. Potential drop near the end plates of the expander appears to be much lower than the electron temperature in the center of the trap. Characteristic energy of electrons in the expander region is also substantially lower than the electron temperature in the confinement plasma. Variation of the magnetic field expansion ratio K between 30 and 160 does not influence the main parameters of the confinement plasma. Electron temperatures of the confinement plasma of about 700 eV were achieved at K = 30.

  15. Magnetic properties of hybrid elastomers with magnetically hard fillers: rotation of particles

    Science.gov (United States)

    Stepanov, G. V.; Borin, D. Yu; Bakhtiiarov, A. V.; Storozhenko, P. A.

    2017-03-01

    Hybrid magnetic elastomers belonging to the family of magnetorheological elastomers contain magnetically hard components and are of the utmost interest for the development of semiactive and active damping devices as well as actuators and sensors. The processes of magnetizing of such elastomers are accompanied by structural rearrangements inside the material. When magnetized, the elastomer gains its own magnetic moment resulting in changes of its magneto-mechanical properties, which remain permanent, even in the absence of external magnetic fields. Influenced by the magnetic field, magnetized particles move inside the matrix forming chain-like structures. In addition, the magnetically hard particles can rotate to align their magnetic moments with the new direction of the external field. Such an elastomer cannot be demagnetized by the application of a reverse field.

  16. Measurement of low-energy Na^+ -- Na total collision rate in an ion--neutral hybrid trap

    CERN Document Server

    Goodman, D S; Kwolek, J M; Blümel, R; Narducci, F A; Smith, W W

    2014-01-01

    We present measurements of the total elastic and resonant charge-exchange ion-atom collision rate coefficient $k_\\mathrm{ia}$ of cold sodium (\\ce{Na}) with optically-dark low energy \\ce{Na+} ions in a hybrid ion-neutral trap. To determine $k_\\mathrm{ia}$, we measured the trap loading and loss from both a \\ce{Na} magneto-optical trap (MOT) and a linear radio frequency quadrupole Paul trap. We found the total rate coefficient to be $7.4 \\pm 1.9 \\times 10^{-8}$ cm$^3$/s for the type I \\ce{Na} MOT immersed within an $\\approx 140$ K ion cloud and $1.10 \\pm 0.25 \\times 10^{-7}$ cm$^3$/s for the type II \\ce{Na} MOT within an $\\approx 1070$ K ion cloud. Our measurements show excellent agreement with previously reported theoretical fully quantal \\textit{ab initio} calculations. In the process of determining the total rate coefficient, we demonstrate that a MOT can be used to probe an optically dark ion cloud's spatial distribution within a hybrid trap.

  17. Statics of levitated vehicle model with hybrid magnets

    Institute of Scientific and Technical Information of China (English)

    Desheng LI; Zhiyuan LU; Tianwu DONG

    2009-01-01

    By studying the special characteristics of permanent and electronic magnets, a levitated vehicle model with hybrid magnets is established. The mathematical model of the vehicle is built based on its dynamics equation by studying its machine structure and working principle. Based on the model, the basic characteristics and the effect between the excluding forces from permanent magnets in three different spatial directions are analyzed, statics characteristics of the interference forces in three different spatial directions are studied, and self-adjusting equilibrium characteristics and stabilization are analyzed. Based on the structure above, the vehicle can levitate steadily by control system adjustment.

  18. Magnetic multipole induced zero-rotation frequency bounce-resonant loss in a Penning-Malmberg trap used for antihydrogen trapping

    Science.gov (United States)

    Andresen, G. B.; Bertsche, W.; Bray, C. C.; Butler, E.; Cesar, C. L.; Chapman, S.; Charlton, M.; Fajans, J.; Fujiwara, M. C.; Gill, D. R.; Hardy, W. N.; Hayano, R. S.; Hayden, M. E.; Humphries, A. J.; Hydomako, R.; Jørgensen, L. V.; Kerrigan, S. J.; Keller, J.; Kurchaninov, L.; Lambo, R.; Madsen, N.; Nolan, P.; Olchanski, K.; Olin, A.; Povilus, A.; Pusa, P.; Robicheaux, F.; Sarid, E.; El Nasr, S. Seif; Silveira, D. M.; Storey, J. W.; Thompson, R. I.; van der Werf, D. P.; Wurtele, J. S.; Yamazaki, Y.

    2009-10-01

    In many antihydrogen trapping schemes, antiprotons held in a short-well Penning-Malmberg trap are released into a longer well. This process necessarily causes the bounce-averaged rotation frequency Ω¯r of the antiprotons around the trap axis to pass through zero. In the presence of a transverse magnetic multipole, experiments and simulations show that many antiprotons (over 30% in some cases) can be lost to a hitherto unidentified bounce-resonant process when Ω¯r is close to zero.

  19. Magnetic multipole induced zero-rotation frequency bounce-resonant loss in a Penning–Malmberg trap used for antihydrogen trapping

    CERN Document Server

    Andresen, G B; Bray, C; Butler, E; Cesar, C L; Chapman, S; Charlton, M; Fajans, J; Fujiwara, M C; Gill, D R; Hardy, W N; Hayano, R S; Hayden, M E; Humphries, A J; Hydomako, R; Jørgensen, L V; Kerrigan, S J; Keller, J; Kurchaninov, L; Lambo, R; Madsen, N; Nolan, P; Olchanski, K; Olin, A; Povilus, A; Pusa, P; Robicheaux, F; Sarid, E; Seif El Nasr, S; Silveira, D M; Storey, J W; Thompson, R I; van der Werf, D P; Wurtele, J S; Yamazaki, Y

    2009-01-01

    In many antihydrogen trapping schemes, antiprotons held in a short-well Penning–Malmberg trap are released into a longer well. This process necessarily causes the bounce-averaged rotation frequency $\\overline{\\Omega}_r$ of the antiprotons around the trap axis to pass through zero. In the presence of a transverse magnetic multipole, experiments and simulations show that many antiprotons (over 30% in some cases) can be lost to a hitherto unidentified bounce-resonant process when $\\overline{\\Omega}_r$ is close to zero.

  20. Magnetic equivalent circuit model for unipolar hybrid excitation synchronous machine

    Directory of Open Access Journals (Sweden)

    Kupiec Emil

    2015-03-01

    Full Text Available Lately, there has been increased interest in hybrid excitation electrical machines. Hybrid excitation is a construction that combines permanent magnet excitation with wound field excitation. Within the general classification, these machines can be classified as modified synchronous machines or inductor machines. These machines may be applied as motors and generators. The complexity of electromagnetic phenomena which occur as a result of coupling of magnetic fluxes of separate excitation systems with perpendicular magnetic axis is a motivation to formulate various mathematical models of these machines. The presented paper discusses the construction of a unipolar hybrid excitation synchronous machine. The magnetic equivalent circuit model including nonlinear magnetization curves is presented. Based on this model, it is possible to determine the multi-parameter relationships between the induced voltage and magnetomotive force in the excitation winding. Particular attention has been paid to the analysis of the impact of additional stator and rotor yokes on above relationship. Induced voltage determines the remaining operating parameters of the machine, both in the motor and generator mode of operation. The analysis of chosen correlations results in an identification of the effective control range of electromotive force of the machine.

  1. A Practical Permanent Magnetic Motor Drive for Hybrid Motorcycle

    Institute of Scientific and Technical Information of China (English)

    崔巍; 江建中; 邵定国; 杨斌

    2003-01-01

    A novel embedded-type permanent magnetic motor for hybrid motorcycle, which employs asymmetric design of eccentric air-gap, is proposed in the paper. This special design of air-gap well conforms to the mono-directional operation characteristic of motorcycle and effectively suppresses the distortion of air-gap magnetic field caused by armature reaction. Hence the torque ripple is reduced. A drive system consisting of the newly-designed Nd-Fe-B permanent magnet synchronous motor and parallel-MOSFET threephase inverter for hybrid motorcycle propulsion is established. Wide-range speed operation is realized through a simple and novel control strategy. Computer simulation is described and experimental results given to verify the practicality of the proposed motor design and control strategy.

  2. Evaluation of Trapped Magnetic Field Properties in Superconducting MgB2 Bulk Magnets of Various Shapes by Finite Element Method

    Science.gov (United States)

    Hiramatsu, Y.; Otabe, E. S.; Kiuchi, M.

    The trapped magnetic field properties of superconducting MgB2 bulk magnets with various shapes such as a triangular, a quadrangular, a hexangular bulk were calculated by the Finite Elements Method (FEM). The effect for the combination of several numbers of bulks was also investigated for several kinds of shapes to obtain large area of bulk surface in spite of one large bulk. In this calculation, the simple magnetization process replaced by the field-cool magnetization was used to obtain the equivalent distribution of the magnetic field, and the thermal equation in FEM was omitted. The trapped magnetic field for the triangular bulk by FEM was compared with the experimental result. It was found that the calculated results agreed well with the experimental result. The maximum trapped magnetic field was obtained in the cylindrical shape among several kinds of shapes. The trapped magnetic field was increased by the combination of multi-bulks. It was confirmed that the trapped magnetic field of the multi-bulks was larger than that of the single bulk. The trapped magnetic field increases with increasing the number of the bulks.

  3. Formation of van der Waals molecules in buffer-gas-cooled magnetic traps [corrected].

    Science.gov (United States)

    Brahms, N; Tscherbul, T V; Zhang, P; Kłos, J; Sadeghpour, H R; Dalgarno, A; Doyle, J M; Walker, T G

    2010-07-16

    We predict that a large class of helium-containing cold polar molecules form readily in a cryogenic buffer gas, achieving densities as high as 10(12)  cm(-3). We explore the spin relaxation of these molecules in buffer-gas-loaded magnetic traps and identify a loss mechanism based on Landau-Zener transitions arising from the anisotropic hyperfine interaction. Our results show that the recently observed strong T(-6) thermal dependence of the spin-change rate of silver (Ag) trapped in dense (3)He is accounted for by the formation and spin change of Ag(3)He van der Waals molecules, thus providing indirect evidence for molecular formation in a buffer-gas trap.

  4. On-demand rapid transport and stable trapping of nanoparticles of nanoparticles by a hybrid electrothermoplasmonic nanotweezer (Conference Presentation)

    Science.gov (United States)

    Ndukaife, Justus C.; Nnanna, Agbai George Agwu; Kildishev, Alexander V.; Shalaev, Vladimir M.; Wereley, Steven T.; Boltasseva, Alexandra

    2016-09-01

    In plasmon nano-optical tweezers, plasmonic nanoantennas are illuminated to generate highly localized and enhanced electromagnetic field in the vicinity of the nanoantenna. The highly localized and enhanced electromagnetic field creates much stronger optical gradient forces and tighter potential wells for confining particles than in conventional optical tweezers, thus providing a means to trap nanoscale objects and molecules. This approach have been successfully applied for trapping small particles such as protein molecules. However a long standing problem in this field is how to rapidly load the potential well without relying on Brownian diffusion. Conventional design rely on Brownian diffusion to load the trap, which is very slow and could take several minutes to hours depending on the concentration of the nanoscale objects. Furthermore since the plasmonic trapping sites are pre-patterned on a substrate, current plasmonic nanotweezers suffer from the problem of lack of dynamic control over the particles in the trap. Recently we have addressed these challenges by introducing a novel design paradigm known as the Hybrid Electrothermoplasmonic Nanotweezer (HENT)1, where the intrinsic photo-induced heating of the plasmonic nanoantenna is combined with an applied AC electric field to induce a large scale microfluidic flow on-demand. The microfluidic flow enables rapid delivery of suspended nanoparticles to an illuminated plasmonic nanoantenna where they are trapped within a few seconds. In this talk I will discuss the working principle of HENT, as well as HENT-based nanotweezers utilizing alternative plasmonic materials.

  5. Chemical Reaction of Ultracold Atoms and Ions in a Hybrid Trap

    CERN Document Server

    Rellergert, Wade G; Kotochigova, Svetlana; Petrov, Alexander; Chen, Kuang; Schowalter, Steven J; Hudson, Eric R

    2011-01-01

    Interactions between cold ions and atoms have been proposed for use in implementing quantum gates\\cite{Idziaszek2007}, probing quantum gases\\cite{Sherkunov2009}, observing novel charge-transport dynamics\\cite{Cote2000}, and sympathetically cooling atomic and molecular systems which cannot be laser cooled\\cite{Smith2005,Hudson2009}. Furthermore, the chemistry between cold ions and atoms is foundational to issues in modern astrophysics, including the formation of stars, planets, and interstellar clouds\\cite{Smith1992}, the diffuse interstellar bands\\cite{Reddy2010}, and the post-recombination epoch of the early universe\\cite{Stancil1996b}. However, as pointed out in refs 9 and 10, both experimental data and a theoretical description of the ion-atom interaction at low temperatures, reached in these modern atomic physics experiments and the interstellar environment, are still largely missing. Here we observe a chemical reaction between ultracold $^{174}$Yb$^+$ ions and $^{40}$Ca atoms held in a hybrid trap. We me...

  6. Magnetic grain trapping and the hot excesses around early-type stars

    CERN Document Server

    Rieke, George H; Ballering, Nicholas P

    2015-01-01

    A significant fraction of main sequence stars observed interferometrically in the near infrared have slightly extended components that have been attributed to very hot dust. To match the spectrum appears to require the presence of large numbers of very small (< 200 nm in radius) dust grains. However, particularly for the hotter stars, it has been unclear how such grains can be retained close to the star against radiation pressure force. We find that the expected weak stellar magnetic fields are sufficient to trap nm-sized dust grains in epicyclic orbits for a few weeks or longer, sufficient to account for the hot excess emission. Our models provide a natural explanation for the requirement that the hot excess dust grains be smaller than 200 nm. They also suggest that magnetic trapping is more effective for rapidly rotating stars, consistent with the average vsini measurements of stars with hot excesses being larger (at about 2 sigma) than those for stars without such excesses.

  7. Optical and magnetic measurements of gyroscopically stabilized graphene nanoplatelets levitated in an ion trap

    Science.gov (United States)

    Nagornykh, Pavel; Coppock, Joyce E.; Murphy, Jacob P. J.; Kane, B. E.

    2017-07-01

    Using optical measurements, we demonstrate that the rotation of micron-scale graphene nanoplatelets levitated in a quadrupole ion trap in high vacuum can be frequency-locked to an applied radiofrequency electric field Erf. Over time, frequency-locking stabilizes the nanoplatelet so that its axis of rotation is normal to the nanoplatelet and perpendicular to Erf. We observe that residual slow dynamics of the direction of the axis of rotation in the plane normal to Erf is determined by an applied magnetic field. We present a simple model that accurately describes our observations. From our data and model, we can infer both a diamagnetic polarizability and a magnetic moment proportional to the frequency of rotation, which we compare to theoretical values. Our results establish that trapping technologies have applications for materials measurements at the nanoscale.

  8. MAGNETIC GRAIN TRAPPING AND THE HOT EXCESSES AROUND EARLY-TYPE STARS

    Energy Technology Data Exchange (ETDEWEB)

    Rieke, G. H.; Gáspár, András; Ballering, N. P., E-mail: grieke@as.arizona.edu, E-mail: agaspar@as.arizona.edu, E-mail: ballerin@email.arizona.edu [Steward Observatory, University of Arizona, Tucson, AZ 85721 (United States)

    2016-01-10

    A significant fraction of main sequence stars observed interferometrically in the near-infrared have slightly extended components that have been attributed to very hot dust. To match the spectrum appears to require the presence of large numbers of very small (<200 nm in radius) dust grains. However, particularly for the hotter stars, it has been unclear how such grains can be retained close to the star against radiation pressure force. We find that the expected weak stellar magnetic fields are sufficient to trap nm-sized dust grains in epicyclic orbits for a few weeks or longer, sufficient to account for the hot excess emission. Our models provide a natural explanation for the requirement that the hot excess dust grains be smaller than 200 nm. They also suggest that magnetic trapping is more effective for rapidly rotating stars, consistent with the average vsini measurements of stars with hot excesses being larger (at ∼2σ) than those for stars without such excesses.

  9. Dynamics of magnetically trapped particles foundations of the physics of radiation belts and space plasmas

    CERN Document Server

    Roederer, Juan G

    2014-01-01

    This book is a new edition of Roederer’s classic Dynamics of Geomagnetically Trapped Radiation, updated and considerably expanded. The main objective is to describe the dynamic properties of magnetically trapped particles in planetary radiation belts and plasmas and explain the physical processes involved from the theoretical point of view. The approach is to examine in detail the orbital and adiabatic motion of individual particles in typical configurations of magnetic and electric fields in the magnetosphere and, from there, derive basic features of the particles’ collective “macroscopic” behavior in general planetary environments. Emphasis is not on the “what” but on the “why” of particle phenomena in near-earth space, providing a solid and clear understanding of the principal basic physical mechanisms and dynamic processes involved. The book will also serve as an introduction to general space plasma physics, with abundant basic examples to illustrate and explain the physical origin of diff...

  10. Particle energisation in a collapsing magnetic trap model: the relativistic regime

    CERN Document Server

    Oskoui, Solmaz Eradat

    2014-01-01

    In solar flares, a large number of charged particles is accelerated to high energies. By which physical processes this is achieved is one of the main open problems in solar physics. It has been suggested that during a flare, regions of the rapidly relaxing magnetic field can form a collapsing magnetic trap (CMT) and that this trap may contribute to particle energisation.} In this Research Note we focus on a particular analytical CMT model based on kinematic magnetohydrodynamics. Previous investigations of particle acceleration for this CMT model focused on the non-relativistic energy regime. It is the specific aim of this Research Note to extend the previous work to relativistic particle energies. Particle orbits were calculated numerically using the relativistic guiding centre equations. We also calculated particle orbits using the non-relativistic guiding centre equations for comparison. For mildly relativistic energies the relativistic and non-relativistic particle orbits mainly agree well, but clear devia...

  11. Controlled trapping and detection of magnetic particles by a magnetic microactuator and a giant magnetoresistance (GMR) sensor

    KAUST Repository

    Giouroudi, Ioanna

    2014-04-01

    This paper presents the design and testing of an integrated micro-chip for the controlled trapping and detection of magnetic particles (MPs). A unique magnetic micro-actuator consisting of square-shaped conductors is used to manipulate the MPs towards a giant magnetoresistance (GMR) sensing element which rapidly detects the majority of MPs trapped around the square-shaped conductors. The ability to precisely transport a small number of MPs in a controlled manner over long distances by magnetic forces enables the rapid concentration of a majority of MPs to the sensing zone for detection. This is especially important in low concentration samples. The conductors are designed in such a manner so as to increase the capture efficiency as well as the precision and speed of transportation. By switching current to different conductors, MPs can be manipulated and immobilized on the innermost conductor where the GMR sensor is located. This technique rapidly guides the MPs towards the sensing zone. Secondly, for optimum measurement capability with high spatial resolution the GMR sensor is fabricated directly underneath and all along the innermost conductor to detect the stray fields originating from the MPs. Finally, a microfluidic channel is fabricated on top of this micro-chip. Experiments inside the microchannel were carried out and the MPs were successfully trapped at the sensing area. © (2014) Trans Tech Publications.

  12. Effects of external magnetic trap on two dark solitons of a two-component Bose-Einstein condensate

    Institute of Scientific and Technical Information of China (English)

    Hong Li; D. N. Wang

    2008-01-01

    Two dark solitons are considered in a two-component Bose-Einstein condensate with an external magnetic trap, and effects of the trap potential on their dynamics are investigated by the numerical simulation. The results show that the dark solitons attract, collide and repel periodically in two components as time changes, the time period depends strictly on the initial condition and the potential, and there are obvious self-trapping effects on the two dark solitons.

  13. Spatial configuration of a plasma bunch formed under gyromagnetic resonance in a magnetic mirror trap

    Science.gov (United States)

    Andreev, V. V.; Novitskii, A. A.; Umnov, A. M.; Chuprov, D. V.

    2016-06-01

    The spatial configuration of a relativistic plasma bunch generated under the gyromagnetic autoresonance and confined in a magnetic mirror trap has been studied experimentally and numerically. The characteristics of bremsstrahlung generated by the plasma bunch from the gas and chamber walls were investigated using X-ray spectroscopy and radiometry, which made it possible to determine the localization of the bunch and analyze the dynamics of its confinement.

  14. Magnetic characterisation of large grain, bulk Y–Ba–Cu–O superconductor–soft ferromagnetic alloy hybrid structures

    Energy Technology Data Exchange (ETDEWEB)

    Philippe, M.P., E-mail: M.Philippe@ulg.ac.be [SUPRATECS and Department of Electrical Engineering and Computer Science (B28), University of Liège, 4000 Liège (Belgium); Fagnard, J.-F.; Kirsch, S. [SUPRATECS and Department of Electrical Engineering and Computer Science (B28), University of Liège, 4000 Liège (Belgium); Xu, Z.; Dennis, A.R.; Shi, Y.-H.; Cardwell, D.A. [Bulk Superconductivity Group, Engineering Department, University of Cambridge, Cambridge CB2 1PZ (United Kingdom); Vanderheyden, B.; Vanderbemden, P. [SUPRATECS and Department of Electrical Engineering and Computer Science (B28), University of Liège, 4000 Liège (Belgium)

    2014-07-15

    Highlights: • Large grain, bulk YBaCuO superconductor (SC) combined with ferromagnetic elements. • The flux lines curve outwards through the ferromagnet in the remanent state. • The trapped field in the SC is enhanced by the presence of the ferromagnet. • The effects of the SC and the ferromagnet add when the ferromagnet is saturated. - Abstract: Large grain, bulk Y–Ba–Cu–O (YBCO) high temperature superconductors (HTS) have significant potential for use in a variety of practical applications that incorporate powerful quasi-permanent magnets. In the present work, we investigate how the trapped field of such magnets can be improved by combining bulk YBCO with a soft FeNi, ferromagnetic alloy. This involves machining the alloy into components of various shapes, such as cylinders and rings, which are attached subsequently to the top surface of a solid, bulk HTS cylinder. The effect of these modifications on the magnetic hysteresis curve and trapped field of the bulk superconductor at 77 K are then studied using pick-up coil and Hall probe measurements. The experimental data are compared to finite element modelling of the magnetic flux distribution using Campbell’s algorithm. Initially we establish the validity of the technique involving pick-up coils wrapped around the bulk superconductor to obtain its magnetic hysteresis curve in a non-destructive way and highlight the difference between the measured signal and the true magnetization of the sample. We then consider the properties of hybrid ferromagnet/superconductor (F/S) structures. Hall probe measurements, together with the results of the model, establish that flux lines curve outwards through the ferromagnet, which acts, effectively, like a magnetic short circuit. Magnetic hysteresis curves show that the effects of the superconductor and the ferromagnet simply add when the ferromagnet is saturated fully by the applied field. The trapped field of the hybrid structure is always larger than that of the

  15. Polarized neutron imaging and three-dimensional calculation of magnetic flux trapping in bulk of superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Treimer, Wolfgang; Ebrahimi, Omid; Karakas, Nursel; Prozorov, Ruslan

    2012-05-17

    Polarized neutron radiography was used to study the three-dimensional magnetic flux distribution inside of single-crystal and polycrystalline Pb cylinders with large (cm3) volume and virtually zero demagnetization. Experiments with single crystals being in the Meissner phase (Tmagnetic field. 99.9999 wt % pure polycrystalline samples were exposed to the same homogeneous magnetic field (6.4 mT) and only a portion of the applied field was expelled. The trapped field in the sample (Ttrapped flux was nearly constant. The expelled field outside of the samples followed 1/R dependence. These measurements provided a unique and detailed picture of macroscopic superconducting samples, confirming the existence of both uniform bulk Meissner expulsion in single crystals and bulk flux trapping with nearly-Bean-model profiles due to flux pinning in polycrystalline samples.

  16. Trapping and dynamic manipulation of polystyrene beads mimicking circulating tumor cells using targeted magnetic/photoacoustic contrast agents

    Science.gov (United States)

    Wei, Chen-Wei; Xia, Jinjun; Hu, Xiaoge; Gao, Xiaohu; O’Donnell, Matthew

    2012-01-01

    Abstract. Results on magnetically trapping and manipulating micro-scale beads circulating in a flow field mimicking metastatic cancer cells in human peripheral vessels are presented. Composite contrast agents combining magneto-sensitive nanospheres and highly optical absorptive gold nanorods were conjugated to micro-scale polystyrene beads. To efficiently trap the targeted objects in a fast stream, a dual magnet system consisting of two flat magnets to magnetize (polarize) the contrast agent and an array of cone magnets producing a sharp gradient field to trap the magnetized contrast agent was designed and constructed. A water-ink solution with an optical absorption coefficient of 10  cm−1 was used to mimic the optical absorption of blood. Magnetomotive photoacoustic imaging helped visualize bead trapping, dynamic manipulation of trapped beads in a flow field, and the subtraction of stationary background signals insensitive to the magnetic field. The results show that trafficking micro-scale objects can be effectively trapped in a stream with a flow rate up to 12  ml/min and the background can be significantly (greater than 15 dB) suppressed. It makes the proposed method very promising for sensitive detection of rare circulating tumor cells within high flow vessels with a highly absorptive optical background. PMID:23223993

  17. Trapped field of YBCO single-domain samples using pulse magnetization from 77K to 20K

    Energy Technology Data Exchange (ETDEWEB)

    Chaud, X [CNRS/CRETA, 25 avenue des martyrs, 38042 Grenoble Cedex 09 (France); Haanappel, E [LNCMP, 143 avenue de Rangueil, 31400 Toulouse (France); Noudem, J G; Horvath, D [CRISMAT/ENSICAEN, 6 bd Marechal Juin, 14050 Caen (France)], E-mail: xavier.chaud@grenoble.cnrs.fr

    2008-02-01

    ReBCO single-domain bulk superconductors have been shown to trap significant magnetic field at 77K and below. They can advantageously replace permanent magnets in cryogenic motors; more power in a smaller volume can be achieved. But practically, their magnetization has to be performed in situ. Usually it implies the use of pulse magnetization which is severe for the samples. This technique generates heat and stress on the superconductors. The magnetic-flux-trapping capabilities of YBCO single-domain samples were explored using the pulse-field facilities at the LNCMP (National Pulsed Magnetic Field Laboratory) at Toulouse, France. The flux dynamic was monitored during magnetic pulses by measuring the surface induction with a Hall probe on top of the samples at different temperatures from 77K to 20K. The samples were 16 mm in diameter and about 10 mm in height. The best one trapped 400 mT at 77K and 2.5T at 20K. The trapped field increases almost linearly down to 40K. The magnetic pulse is seen to generate heat. The temperature rise increases with decreasing temperature dwell because of lower heat capacity. The achieved trapped field is a compromise between the temperature rise and the applied field, and depends greatly of the magnetization history.

  18. Trapped magnetic field of a superconducting bulk magnet in high- T sub c RE-Ba-Cu-O

    CERN Document Server

    Fujimoto, H; Higuchi, T; Nakamura, Y; Kamijo, H; Nagashima, K; Murakami, M

    1999-01-01

    Superconducting magnets made of high-T sub c superconductors are promising for industrial applications. It is well known that REBa sub 2 Cu sub 3 O sub 7 sub - sub x and LRE (light rare-earth) Ba sub 2 Cu sub 3 O sub 7 sub - sub x superconductors prepared by melt processes have a high critical current density, J sub c , at 77 K and high magnetic fields. Therefore, the materials are very prospective for high magnetic field application as a superconducting permanent/bulk magnet with liquid-nitrogen refrigeration. LREBaCuO bulks, compared with REBaCuO bulks, exhibit a larger J sub c in high magnetic fields and a much improved irreversibility field, H sub i sub r sub r , at 77 K. In this study, we discuss the possibility and trapped field properties of a superconducting bulk magnet, as well as the melt processing for bulk superconductors and their characteristic superconducting properties. One of the applications is a superconducting magnet for the future magnetically levitated (Maglev) train.

  19. Trapped magnetic field of a superconducting bulk magnet in high- T{sub c} RE-Ba-Cu-O

    Energy Technology Data Exchange (ETDEWEB)

    Fujimoto, Hiroyuki; Yoo, Sang Im; Higuchi, Takamitsu; Nakamura, Yuichi; Kamijo, Hiroki; Nagashima, Ken [Railway Technical Research Institute, Tokyo (Japan); Murakami, Masato [International Superconductivity Technology Center, Tokyo (Japan)

    1999-07-01

    Superconducting magnets made of high-T{sub c} superconductors are promising for industrial applications. It is well known that REBa{sub 2}Cu{sub 3}O{sub 7-x} and LRE (light rare-earth) Ba{sub 2}Cu{sub 3}O{sub 7-x} superconductors prepared by melt processes have a high critical current density, J{sub c}, at 77 K and high magnetic fields. Therefore, the materials are very prospective for high magnetic field application as a superconducting permanent/bulk magnet with liquid-nitrogen refrigeration. LREBaCuO bulks, compared with REBaCuO bulks, exhibit a larger J{sub c} in high magnetic fields and a much improved irreversibility field, H{sub irr}, at 77 K. In this study, we discuss the possibility and trapped field properties of a superconducting bulk magnet, as well as the melt processing for bulk superconductors and their characteristic superconducting properties. One of the applications is a superconducting magnet for the future magnetically levitated (Maglev) train.

  20. Modeling of Hybrid Permanent Magnetic-Gas Bearings

    DEFF Research Database (Denmark)

    Morosi, Stefano; Santos, Ilmar

    2009-01-01

    Modern turbomachinery applications require nowadays ever-growing rotational speeds and high degree of reliability. It then becomes natural to focus the attention of the research to contact-free bearings elements. The present alternatives focus on gas lubricated journal bearings or magnetic bearings....... In the present paper both the technologies are combined with the aim of developing a new kind of hybrid permanent magnetic - gas bearing. This new kind of machine is intended to exploit the benefits of the two technologies while minimizing their drawbacks. The poor start-up and low speed operation performance...... of the gas bearing is balanced by the properties of the passive magnetic one. At high speeds the dynamic characteristics of the gas bearing are improved by offsetting the stator ring of the permanent magnetic bearing. Furthermore this design shows a kind of redundancy, which offers soft failure properties...

  1. Modeling of Hybrid Permanent Magnetic-Gas Bearings

    DEFF Research Database (Denmark)

    Morosi, Stefano; Santos, Ilmar

    2009-01-01

    Modern turbomachinery applications require nowadays ever-growing rotational speeds and high degree of reliability. It then becomes natural to focus the attention of the research to contact-free bearings elements. The present alternatives focus on gas lubricated journal bearings or magnetic bearings...... concentric rings with radial magnetic orientation - analytical expressions for the calculation of the magnetic flux density and forces are employed, opposed to the main literature trend where finite element software is utilized at least for the calculation of the B-field. Numerical analysis shows how...... the rotor equilibrium position can be made independent on the rotational speed and applied load; it becomes function of the passive magnetic bearing offset. By adjusting the offset it is possible to significantly influence the dynamic coefficients of the hybrid bearing....

  2. Photovoltaic-wind hybrid system for permanent magnet DC motor

    Science.gov (United States)

    Nasir, M. N. M.; Lada, M. Y.; Baharom, M. F.; Jaafar, H. I.; Ramani, A. N.; Sulaima, M. F.

    2015-05-01

    Hybrid system of Photovoltaic (PV) - Wind turbine (WT) generation has more advantages and reliable compared to PV or wind turbine system alone. The aim of this paper is to model and design hybrid system of PV-WT supplying 100W permanent-magnet dc motor. To achieve the objective, both of PV and WT are connected to converter in order to get the same source of DC supply. Then both sources were combined and straightly connected to 100W permanent magnet dc motor. All the works in this paper is only applied in circuit simulator by using Matlab Simulink. The output produced from each converter is expected to be suit to the motor specification. The output produced from each renewable energy system is as expected to be high as it can support the motor if one of them is breakdown

  3. Analysis and Design of Hybrid Excitation Permanent Magnet Synchronous Generators

    Institute of Scientific and Technical Information of China (English)

    JIN Wan-bing; ZHANG Dong; AN Zhong-liang; TAN Ren-yuan

    2006-01-01

    On the basis of a conventional permanent magnet (PM) synchronous generator's construction,a novel kind of Hybrid Excitation Permanent Magnet Synchronous Generator (HEPMSG) is introduced by inserting exciting winding in the stator or rotor.Firstly,the construction of HEPMSG is improved with the addition of PM excitation on the ferromagnetic pole,and its working principle and design method are studied in detail.Then,an appropriate exciting current control system is presented considering the characteristics of HEPMSG.Finally,a prototype is made,and test results confirm the analysis and design.

  4. Hybrid material as contrast agent in magnetic resonance images

    OpenAIRE

    Botella Asunción, Pablo; Cabrera García, Alejandro

    2015-01-01

    [EN] The invention relates to a contrast agent of magnetic resonance based on a hybrid material formed by an organo-metallic core derived from Prussian blue and a silica cover, and optionally, molecules of a poly(ethylene glycol), a fluorescent agent, a radio nucleus and/or a substance that directs to specific receptors, cells or tissues, joined by covalent bonding to the surface of the inorganic cover.

  5. Hybrid material as contrast agent in magnetic resonance images

    OpenAIRE

    Botella Asunción, Pablo; Cabrera García, Alejandro

    2015-01-01

    [EN] The invention relates to a contrast agent of magnetic resonance based on a hybrid material formed by an organo-metallic core derived from Prussian blue and a silica cover, and optionally, molecules of a poly(ethylene glycol), a fluorescent agent, a radio nucleus and/or a substance that directs to specific receptors, cells or tissues, joined by covalent bonding to the surface of the inorganic cover.

  6. Modelling and comparison of trapped fields in (RE)BCO bulk superconductors for activation using pulsed field magnetization

    Science.gov (United States)

    Ainslie, M. D.; Fujishiro, H.; Ujiie, T.; Zou, J.; Dennis, A. R.; Shi, Y.-H.; Cardwell, D. A.

    2014-06-01

    The ability to generate a permanent, stable magnetic field unsupported by an electromotive force is fundamental to a variety of engineering applications. Bulk high temperature superconducting (HTS) materials can trap magnetic fields of magnitude over ten times higher than the maximum field produced by conventional magnets, which is limited practically to rather less than 2 T. In this paper, two large c-axis oriented, single-grain YBCO and GdBCO bulk superconductors are magnetized by the pulsed field magnetization (PFM) technique at temperatures of 40 and 65 K and the characteristics of the resulting trapped field profile are investigated with a view of magnetizing such samples as trapped field magnets (TFMs) in situ inside a trapped flux-type superconducting electric machine. A comparison is made between the temperatures at which the pulsed magnetic field is applied and the results have strong implications for the optimum operating temperature for TFMs in trapped flux-type superconducting electric machines. The effects of inhomogeneities, which occur during the growth process of single-grain bulk superconductors, on the trapped field and maximum temperature rise in the sample are modelled numerically using a 3D finite-element model based on the H-formulation and implemented in Comsol Multiphysics 4.3a. The results agree qualitatively with the observed experimental results, in that inhomogeneities act to distort the trapped field profile and reduce the magnitude of the trapped field due to localized heating within the sample and preferential movement and pinning of flux lines around the growth section regions (GSRs) and growth sector boundaries (GSBs), respectively. The modelling framework will allow further investigation of various inhomogeneities that arise during the processing of (RE)BCO bulk superconductors, including inhomogeneous Jc distributions and the presence of current-limiting grain boundaries and cracks, and it can be used to assist optimization of

  7. Improvement of the Levitation Characteristics in the Magnetic Bearing System Using HTSC-Permanent Magnet Hybrid Structure

    Science.gov (United States)

    Ohashi, Shunsuke

    Magnetic bearing using pining force of a permanent magnet and a high-temperature superconductor has been developed. Additional permanent magnet is introduced to increase the levitation force of the magnetic bearing. In this hybrid magnetic bearing system, levitation force is mainly given by the repulsive force of the permanent magnets, and stability for the lateral direction is given by pining force of the superconductor. The experimental device is developed. A ring type superconductor and a bulk one are examined. Levitation characteristics of the hybrid magnetic bearing are measured. A bulk superconductor shows better characteristics both levitation and lateral stability than ring one. Levitation force of the hybrid system becomes about twice as large as that of the no-hybrid one. Although repulsive force of the permanent magnet decreases lateral stability of the system, its influence becomes small by choosing adequate position of the permanent magnets and the superconductor.

  8. Magnetic Hybrid Nanosorbents for the Uptake of Paraquat from Water.

    Science.gov (United States)

    Fernandes, Tiago; Soares, Sofia F; Trindade, Tito; Daniel-da-Silva, Ana L

    2017-03-18

    Although paraquat has been banned in European countries, this herbicide is still used all over the world, thanks to its low-cost, high-efficiency, and fast action. Because paraquat is highly toxic to humans and animals, there is interest in mitigating the consequences of its use, namely by implementing removal procedures capable of curbing its environmental and health risks. This research describes new magnetic nanosorbents composed of magnetite cores functionalized with bio-hybrid siliceous shells, that can be used to uptake paraquat from water using magnetically-assisted procedures. The biopolymers κ-carrageenan and starch were introduced into the siliceous shells, resulting in two hybrid materials, Fe₃O₄@SiO₂/SiCRG and Fe₃O₄@SiO₂/SiStarch, respectively, that exhibit a distinct surface chemistry. The Fe₃O₄@SiO₂/SiCRG biosorbents displayed a superior paraquat removal performance, with a good fitting to the Langmuir and Toth isotherm models. The maximum adsorption capacity of paraquat for Fe₃O₄@SiO₂/SiCRG biosorbents was 257 mg·g(-1), which places this sorbent among the best systems for the removal of this herbicide from water. The interesting performance of the κ-carrageenan hybrid, along with its magnetic properties and good regeneration capacity, presents a very efficient way for the remediation of water contaminated with paraquat.

  9. Magnetic Hybrid Nanosorbents for the Uptake of Paraquat from Water

    Directory of Open Access Journals (Sweden)

    Tiago Fernandes

    2017-03-01

    Full Text Available Although paraquat has been banned in European countries, this herbicide is still used all over the world, thanks to its low-cost, high-efficiency, and fast action. Because paraquat is highly toxic to humans and animals, there is interest in mitigating the consequences of its use, namely by implementing removal procedures capable of curbing its environmental and health risks. This research describes new magnetic nanosorbents composed of magnetite cores functionalized with bio-hybrid siliceous shells, that can be used to uptake paraquat from water using magnetically-assisted procedures. The biopolymers κ-carrageenan and starch were introduced into the siliceous shells, resulting in two hybrid materials, Fe3O4@SiO2/SiCRG and Fe3O4@SiO2/SiStarch, respectively, that exhibit a distinct surface chemistry. The Fe3O4@SiO2/SiCRG biosorbents displayed a superior paraquat removal performance, with a good fitting to the Langmuir and Toth isotherm models. The maximum adsorption capacity of paraquat for Fe3O4@SiO2/SiCRG biosorbents was 257 mg·g−1, which places this sorbent among the best systems for the removal of this herbicide from water. The interesting performance of the κ-carrageenan hybrid, along with its magnetic properties and good regeneration capacity, presents a very efficient way for the remediation of water contaminated with paraquat.

  10. Study on the Levitation and Restoring Force Characteristics of the Improved HTS-permanent Magnet Hybrid Magnetic Bearing

    Science.gov (United States)

    Sugiyama, R.; Oguni, K.; Ohashi, S.

    We have developed the hybrid magnetic bearing using permanent magnets and high temperature bulk super conductor (HTS). In this system, the permanent magnet has ring type structure so that the permanent magnet and the HTS can be set to the stator. The pinning force of the HTS is used for the levitation and the guidance. Repulsive force of the permanent magnets was used in the conventional hybrid system. However the restoring force in the guidance direction of the conventional hybrid system decreases by the side slip force of the permanent magnets. In this research, attractive force of permanent magnets is used for increasing the load weight in the guidance direction. In this paper, influence of the hybrid system on the static characteristics of the rotor is studied. Three-dimensional numerical analysis of the linkage flux (in the levitation and the guidance direction) in the HTS is undertaken. The stator side permanent magnet increases the linkage flux of the levitation direction. Therefore in the hybrid system the linkage flux of the levitation direction increases. The levitation and restoring force of the rotor is measured. The levitation force of the hybrid system becomes smaller than that of the non-hybrid one by attractive force. The rotor in the hybrid system is supported by the pinning force and attractive force. The restoring force of the hybrid system becomes larger than that of the non-hybrid one because of increasing the linkage flux of the levitation direction.

  11. Experimental investigations on the splitting of coherent population trapping resonances by the nuclear magnetic moment

    Energy Technology Data Exchange (ETDEWEB)

    Lammegger, Roland; Vasari, Ivan; Neureiter, Christian; Windholz, Laurentius [Inst. f. Experimentalphysik, Techn. Univ. Graz (Austria)

    2007-07-01

    Coherent population trapping (CPT) is a resonance phenomenon due to a quantum mechanical interference effect within an atomic system. The resonantly driven atomic level population is being trapped into a superpositional dark state, yielding the atomic medium transparent for the exciting electromagnetic fields. The observation of this effect requires a special electronic structure ({lambda}-system) and suitable lifetimes which can be found e.g. in alkali atoms. We present experimental investigations on the behavior of the CPT resonances split by the nuclear magnetic moment under different external magnetic fields, laser polarizations and laser intensities. We focus our considerations on a special type of the {lambda}-System formation. In this case the center of gravity of the pair of split CPT resonances (called pseudoresonance) is sensitive to external magnetic fields only to second order in the magnetic field strength. The short term frequency stability of this pseudoresonance approaches the level of 10{sup -14}/{radical}({tau}). Thus such resonances seems to be a good candidate for applications in compact atomic clocks used e.g. in GPS receivers and Satellites.

  12. High throughput transfection of cells: nano-electroporation and mobile magnetic traps

    Science.gov (United States)

    Howdyshell, M.; Gallego-Perez, D.; Vieira, G.; Malkoc, V.; Lee, L. J.; Sooryakumar, R.

    2014-03-01

    Injection of drugs or genes in vitro into cells is a critical technique for biomedical research; there are currently a number of techniques to perform such injections, but drawbacks include lack of control over dosage rates and sustained cell viability, as well as inability to inject into many cells in parallel. We have previously demonstrated a magnetically actuated nano-channel electroporation technique that multiplexes simultaneous transfection of biomolecules into cells by combining an array of remotely operated micro-magnetic traps with a nano-channel electroporation device. This device allows us to control the dosage delivered to each individual cell and reduce cell death during the experiment. The magnetic traps enable precise positioning of magnetically labeled cells and subsequent relocation of the cells for downstream processing. With this integrated approach, the number of cells transfected simultaneously has been increased nearly tenfold. In the current work, we present recent experiments with different types of cells as well as new multiplexed nano-electroporation device designs that are more high-throughput to streamline the parallel injection process, allowing the device to be implemented for a wider variety of applications.

  13. Quantum Magnetism of Spin-Ladder Compounds with Trapped-Ion Crystals

    CERN Document Server

    Bermudez, A; Ott, K; Kaufmann, H; Ulm, S; Schmidt-Kaler, F; Retzker, A; Plenio, M B

    2012-01-01

    The quest for experimental platforms that allow for the exploration, and even control, of the interplay of low dimensionality and frustration is a fundamental challenge in several fields of quantum many-body physics, such as quantum magnetism. Here, we propose the use of cold crystals of trapped ions to study a variety of frustrated quantum spin ladders. By optimizing the trap geometry, we show how to tailor the low dimensionality of the models by changing the number of legs of the ladders. Combined with a method for selectively hiding of ions provided by laser addressing, it becomes possible to synthesize stripes of both triangular and Kagome lattices. Besides, the degree of frustration of the phonon-mediated spin interactions can be controlled by shaping the trap frequencies. We support our theoretical considerations by initial experiments with planar ion crystals, where a high and tunable anisotropy of the radial trap frequencies is demonstrated. We take into account an extensive list of possible error sou...

  14. Magnetic properties of the magnetic hybrid membranes based on various polymer matrices and inorganic fillers

    Energy Technology Data Exchange (ETDEWEB)

    Rybak, Aleksandra, E-mail: Aleksandra.Rybak@polsl.pl [Department of Physical Chemistry and Technology of Polymers, Faculty of Chemistry, Silesian University of Technology, Strzody 9, 44-100 Gliwice (Poland); Kaszuwara, Waldemar [Faculty of Materials Science and Engineering, Warsaw University of Technology, Woloska 141, 02-507 Warszawa (Poland)

    2015-11-05

    Magnetic hybrid membranes based on ethylcellulose (EC), poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) and various magnetic praseodymium and neodymium powder microparticles as fillers were obtained. Permeability, diffusion and sorption coefficients of O{sub 2}, N{sub 2} and synthetic air components were estimated for homogeneous and heterogeneous membranes using the Time Lag method based on constant pressure permeation technique. The microstructure studies and the phase analysis of magnetic membranes were also performed using SEM and XRD. The influence of magnetic parameters, like coercivity, remanence and saturation magnetization of created membranes on the gas transport properties was studied. The results showed that their coercivity depended on composition and microstructure of the magnetic powder. On the other hand, remanence and saturation magnetization increased with the increase of the powder addition in the membrane. It was found that the magnetic membrane's gas transport properties were improved with the increase of membrane's remanence, saturation magnetization and magnetic particle filling. The decrease in powder particle size and associated increase of the membrane's coercivity also positively influenced the gas transport and separation properties of investigated membranes. It was observed that the magnetic ethylcellulose and poly(2,6-dimethyl-1,4-phenylene oxide) membranes had higher gas permeability, while their permselectivity and solubility coefficient values were rather maintained or slightly increased. The results also showed that the magnetic powder content enhanced significantly gas diffusivity in EC and PPO membranes. It was also analyzed the dependence of the drift coefficient w on the magnetic parameters of investigated membranes. The correlation between the membrane selectivity, permeability and magnetic properties with their XRD characteristics was stated. - Highlights: • Membrane's production consisting of EC or PPO

  15. Trapped Field Characteristics of Stacked YBCO Thin Plates for Compact NMR Magnets: Spatial Field Distribution and Temporal Stability.

    Science.gov (United States)

    Hahn, Seungyong; Kim, Seok Beom; Ahn, Min Cheol; Voccio, John; Bascuñán, Juan; Iwasa, Yukikazu

    2010-06-01

    This paper presents experimental and analytical results of trapped field characteristics of a stack of square YBCO thin film plates for compact NMR magnets. Each YBCO plate, 40 mm × 40 mm × 0.08 mm, has a 25-mm diameter hole at its center. A total of 500 stacked plates were used to build a 40-mm long magnet. Its trapped field, in a bath of liquid nitrogen, was measured for spatial field distribution and temporal stability. Comparison of measured and analytical results is presented: the effects on trapped field characteristics of the unsaturated nickel substrate and the non-uniform current distribution in the YBCO plate are discussed.

  16. On the multistream approach of relativistic Weibel instability. II. Bernstein-Greene-Kruskal-type waves in magnetic trapping

    Energy Technology Data Exchange (ETDEWEB)

    Ghizzo, A. [Institut Jean Lamour UMR 7163, Université de Lorraine, BP 239 F-54506 Vandoeuvre les Nancy (France)

    2013-08-15

    The stationary state with magnetically trapped particles is investigated at the saturation of the relativistic Weibel instability, within the “multiring” model in a Hamiltonian framework. The multistream model and its multiring extension have been developed in Paper I, under the assumption that the generalized canonical momentum is conserved in the perpendicular direction. One dimensional relativistic Bernstein-Greene-Kruskal waves with deeply trapped particles are addressed using similar mathematical formalism developed by Lontano et al.[Phys. Plasmas 9, 2562 (2002); Phys. Plasmas 10, 639 (2003)] using several streams and in the presence of both electrostatic and magnetic trapping mechanisms.

  17. Active control of light trapping by means of local magnetic coupling.pdf

    CERN Document Server

    Burresi, Matteo; van Oosten, Dries; Prangsma, Jord C; Song, Bong-Shik; Noda, Susumo; Kuipers, Laurens

    2009-01-01

    The ability to actively tune the properties of a nanocavity is crucial for future applications in photonics and quantum information. Two important man-made classes of materials have emerged to mold the flow of electromagnetic waves. Firstly, photonic crystals are dielectric nanostructures that can be used to confine and slow down light and control its emission. They act primarily on the electric component of the light field. More recently, a novel class of metallo-dielectric nanostructures has emerged. These so-called metamaterials enable fascinating phenomena, such as negative refraction, super-focusing and cloaking. This second class of materials realizes light control through effective interactions with both electric and magnetic component. In this work, we combine both concepts to gain an active and reversible control of light trapping on subwavelength length scales. By actuating a nanoscale magnetic coil close to a photonic crystal nanocavity, we interact with the rapidly varying magnetic field and accom...

  18. Control of light trapping in a large atomic system by a static magnetic field

    CERN Document Server

    Skipetrov, S E; Havey, M D

    2016-01-01

    We propose to control light trapping in a large ensemble of cold atoms by an external, static magnetic field. For an appropriate choice of frequency and polarization of the exciting pulse, the field is expected to speed up the fluorescence of a dilute atomic system but can significantly slow it down in a dense ensemble. The slowing down of fluorescence is due to the excitation of spatially localized collective atomic states that appear only under a strong magnetic field and have exponentially long lifetimes. The control of fluorescence by the magnetic field may be of interest for use in future quantum-information processing devices. It also paves a way towards the experimental observation of the disorder-induced localization of light in cold atomic systems.

  19. A review of the hybrid techniques for the fabrication of hard magnetic microactuators based on bonded magnetic powders

    Science.gov (United States)

    Pallapa, M.; Yeow, J. T. W.

    2015-02-01

    Polymer composites based on permanent magnetic bonded powders exhibit immense potential for applications in microactuators and sensors with magnetic performances comparable to their fully dense counterparts. While fabrication and integration of magnetic devices based on bonded magnetic powders is challenging via conventional deposition and electrochemical growth techniques, hybrid fabrication offers a promising alternative. This paper presents the evolution of permanent magnetic materials into bonded magnetic powders, the magnetic performance figures of merit of permanent magnetic materials significant for the design and manufacture of polymer based sensors and actuators. A review of the hybrid fabrication techniques such as replica molding, squeegee coating, spin casting etc are reported. Critical factors affecting the fabrication of polymer magnetic composites such as filler particle size and effect of magnetic field during fabrication are discussed. Prior art based on polymer magnetic composites for the fabrication of hard magnetic films and hard magnetic actuators are presented.

  20. Quasi-optical theory of microwave plasma heating in open magnetic trap

    Science.gov (United States)

    Shalashov, A. G.; Balakin, A. A.; Gospodchikov, E. D.; Khusainov, T. A.

    2016-11-01

    Microwave heating of a high-temperature plasma confined in a large-scale open magnetic trap, including all important wave effects like diffraction, absorption, dispersion, and wave beam aberrations, is described for the first time within the first-principle technique based on consistent Maxwell's equations. With this purpose, the quasi-optical approach is generalized over weakly inhomogeneous gyrotrotropic media with resonant absorption and spatial dispersion, and a new form of the integral quasi-optical equation is proposed. An effective numerical technique for this equation's solution is developed and realized in a new code QOOT, which is verified with the simulations of realistic electron cyclotron heating scenarios at the Gas Dynamic Trap at the Budker Institute of Nuclear Physics (Novosibirsk, Russia).

  1. Quasi-optical theory of microwave plasma heating in open magnetic trap

    CERN Document Server

    Shalashov, A G; Gospodchikov, E D; Khusainov, T A

    2016-01-01

    Microwave heating of a high-temperature plasma confined in a large-scale open magnetic trap, including all important wave effects like diffraction, absorption, dispersion and wave beam aberrations, is described for the first time within the first-principle technique based on consistent Maxwell's equations. With this purpose, the quasi-optical approach is generalized over weakly inhomogeneous gyrotrotropic media with resonant absorption and spatial dispersion, and a new form of the integral quasi-optical equation is proposed. An effective numerical technique for this equation's solution is developed and realized in a new code QOOT, which is verified with the simulations of realistic electron cyclotron heating scenarios at the Gas Dynamic Trap at the Budker Institute of Nuclear Physics (Novosibirsk, Russia).

  2. A rare-earth-magnet ion trap for confining low-Z, bare nuclei

    Science.gov (United States)

    Brewer, Samuel M.; Tan, Joseph N.

    2009-05-01

    Simplifications in the theory for Rydberg states of hydrogenlike ions allow a substantial improvement in the accuracy of predicted levels, which can yield information on the values of fundamental constants and test theory if they can be compared with precision frequency measurements.[1] We consider the trapping of bare nuclei (fully-stripped) to be used in making Rydberg states of one-electron ions with atomic number 1earth permanent magnets, and to model the capture of charge-state-selected ions extracted from an electron beam ion trap (EBIT). An experimental apparatus adapted to the NIST EBIT will also be discussed. Reference: [1] U.D. Jentschura, P.J. Mohr, J.N. Tan, and B.J. Wundt, ``Fundamental constants and tests of theory in Rydberg states of hydrogenlike ions,'' Phys. Rev. Lett. 100, 160404 (2008).

  3. Developing Density of Laser-Cooled Neutral Atoms and Molecules in a Linear Magnetic Trap

    Science.gov (United States)

    Velasquez, Joe, III; Walstrom, Peter; di Rosa, Michael

    2013-05-01

    In this poster we show that neutral particle injection and accumulation using laser-induced spin flips may be used to form dense ensembles of ultracold magnetic particles, i.e., laser-cooled paramagnetic atoms and molecules. Particles are injected in a field-seeking state, are switched by optical pumping to a field-repelled state, and are stored in the minimum-B trap. The analogous process in high-energy charged-particle accumulator rings is charge-exchange injection using stripper foils. The trap is a linear array of sextupoles capped by solenoids. Particle-tracking calculations and design of our linear accumulator along with related experiments involving 7Li will be presented. We test these concepts first with atoms in preparation for later work with selected molecules. Finally, we present our preliminary results with CaH, our candidate molecule for laser cooling. This project is funded by the LDRD program of Los Alamos National Laboratory.

  4. High-Resolution Imaging and Optical Control of Bose-Einstein Condensates in an Atom Chip Magnetic Trap

    CERN Document Server

    Salim, Evan A; Pfeiffer, Jonathan B; Anderson, Dana Z

    2012-01-01

    A high-resolution projection and imaging system for ultracold atoms is implemented using a compound silicon and glass atom chip. The atom chip is metalized to enable magnetic trapping while glass regions enable high numerical aperture optical access to atoms residing in the magnetic trap about 100 microns below the chip surface. The atom chip serves as a wall of the vacuum system, which enables the use of commercial microscope components for projection and imaging. Holographically generated light patterns are used to optically slice a cigar-shaped magnetic trap into separate regions; this has been used to simultaneously generate up to four Bose-condensates. Using fluorescence techniques we have demonstrated in-trap imaging resolution down to 2.5 microns

  5. Fast Transverse Beam Instability Caused by Electron Cloud Trapped in Combined Function Magnets

    Energy Technology Data Exchange (ETDEWEB)

    Antipov, Sergey [Univ. of Chicago, IL (United States)

    2017-03-01

    Electron cloud instabilities affect the performance of many circular high-intensity particle accelerators. They usually have a fast growth rate and might lead to an increase of the transverse emittance and beam loss. A peculiar example of such an instability is observed in the Fermilab Recycler proton storage ring. Although this instability might pose a challenge for future intensity upgrades, its nature had not been completely understood. The phenomena has been studied experimentally by comparing the dynamics of stable and unstable beam, numerically by simulating the build-up of the electron cloud and its interaction with the beam, and analytically by constructing a model of an electron cloud driven instability with the electrons trapped in combined function dipoles. Stabilization of the beam by a clearing bunch reveals that the instability is caused by the electron cloud, trapped in beam optics magnets. Measurements of microwave propagation confirm the presence of the cloud in the combined function dipoles. Numerical simulations show that up to 10$^{-2}$ of the particles can be trapped by their magnetic field. Since the process of electron cloud build-up is exponential, once trapped this amount of electrons significantly increases the density of the cloud on the next revolution. In a combined function dipole this multi-turn accumulation allows the electron cloud reaching final intensities orders of magnitude greater than in a pure dipole. The estimated fast instability growth rate of about 30 revolutions and low mode frequency of 0.4 MHz are consistent with experimental observations and agree with the simulations. The created instability model allows investigating the beam stability for the future intensity upgrades.

  6. Conceptual Design of the 45 T Hybrid Magnet at the Nijmegen High Field Magnet Laboratory

    CERN Document Server

    Wiegers, SAJ; Bird, M D; Rook, J; Perenboom, J A A J; Wiegers, S A J; Bonito-Oliva, A; den Ouden, A

    2010-01-01

    A 45 T Hybrid Magnet System is being developed at the Nijmegen High Field Magnet Laboratory as part of the Nijmegen Center for Advanced Spectroscopy. The 45 T Hybrid Magnet System will be used in combination with far-infra-red light produced by a Free Electron Laser under construction directly adjacent to the High Field Magnet Laboratory. The superconducting outsert magnet will consist of three CICC coils wound on a single coil form, using Nb3Sn strands. A test program for strand and cable qualification is underway. The CICC will carry 13 kA and the coils will produce 12 T on axis field in a 600 mm warm bore. The nominal operating temperature will be 4.5 K maintained with forced-flow supercritical helium. The insert magnet will produce 33 T at 40 kA in a 32 mm bore consuming 20 MW, and will consist of four coils. The insert magnet will be galvanically and mechanically isolated from the outsert magnet. Complete system availability for users is expected in 2014. In this paper we will report on the conceptual de...

  7. Control of ion density distribution by magnetic traps for plasma electrons

    Energy Technology Data Exchange (ETDEWEB)

    Baranov, Oleg; Romanov, Maxim [Plasma Laboratory, National Aerospace University ' KhAI,' Kharkov 61070 (Ukraine); Fang Jinghua [Plasma Nanoscience Centre Australia (PNCA), CSIRO Materials Science and Engineering, P.O. Box 218, Lindfield, New South Wales 2070 (Australia); School of Physics, University of Melbourne, Parkville, VIC 3010 (Australia); Cvelbar, Uros [Jozef Stefan Institute, Jamova cesta 39, SI-1000 Ljubljana (Slovenia); Ostrikov, Kostya [Plasma Nanoscience Centre Australia (PNCA), CSIRO Materials Science and Engineering, P.O. Box 218, Lindfield, New South Wales 2070 (Australia); University of Sydney, Sydney, NSW 2006 (Australia)

    2012-10-01

    The effect of a magnetic field of two magnetic coils on the ion current density distribution in the setup for low-temperature plasma deposition is investigated. The substrate of 400 mm diameter is placed at a distance of 325 mm from the plasma duct exit, with the two magnetic coils mounted symmetrically under the substrate at a distance of 140 mm relative to the substrate centre. A planar probe is used to measure the ion current density distribution along the plasma flux cross-sections at distances of 150, 230, and 325 mm from the plasma duct exit. It is shown that the magnetic field strongly affects the ion current density distribution. Transparent plastic films are used to investigate qualitatively the ion density distribution profiles and the effect of the magnetic field. A theoretical model is developed to describe the interaction of the ion fluxes with the negative space charge regions associated with the magnetic trapping of the plasma electrons. Theoretical results are compared with the experimental measurements, and a reasonable agreement is demonstrated.

  8. Microfluidic biosensing device for controlled trapping and detection of magnetic microparticles

    KAUST Repository

    Giouroudi, Ioanna

    2013-05-01

    A magnetic microfluidic device is proposed to transport and trap magnetic microparticles (MPs) to a sensing area. Once the MPs are concentrated in the vicinity of the sensing area, a spin valve type giant magnetoresistance (GMR) sensor is used to detect their presence. The device is used for the detection of biological targets once they are labeled with functionalized MPs. Manipulation of the MPs is achieved by employing a microstructure which consists of planar ringshaped conducting microloops. These microloops are designed to produce high magnetic field gradients which are directly proportional to the force applied to manipulate the MPs. Upon sequential application of current, starting from the outermost loop, MPs are directed to move from the outermost to the innermost loop. The speed with which the MPs move towards the sensing area is controlled by the speed with which current is switched between the loops. On top of the microstructure, a microfluidic channel is fabricated using a standard photolithography technique and a dry film resist layer (Ordyl SY355). Experimental results showed that MPs of different diameters were successfully trapped at the sensing area and detected by the GMR sensor located directly under the innermost square loop. © 2013 IEEE.

  9. Improvement of the rotational characteristics in the HTSC-permanent magnet hybrid bearing using ring shaped magnet

    Energy Technology Data Exchange (ETDEWEB)

    Emoto, Kozo; Sugiyama, Ryo; Takagi, Shogo; Ohashi, Shunsuke, E-mail: k145676@kansai-u.ac.jp

    2013-11-15

    Highlights: •We have developed the HTS-permanent magnet hybrid bearing system. •Three dimensional numerical analysis is undertaken to get the effective hybrid configuration. •Repulsive force and pinning force are combined effectively. •The hybrid system shows better levitation characteristics than the non-hybrid one. •In the mechanical resonance state, vibration of the rotor in the hybrid system is small. -- Abstract: We have developed the hybrid magnetic bearing using permanent magnets and the high-T{sub c} bulk superconductor (HTSC). Pinning force of the HTSC is used for the levitation and the guidance. Repulsive force of the permanent magnets is introduced to increase the load weight of the magnetic bearing. In this system, the stator side permanent magnet has the ring type structure so that both pinning force and repulsive force are used effectively. In this paper, influence of the hybrid system on dynamic characteristics of the rotor is studied. The rotor which is supported by the hybrid magnetic bearing is rotated. Then, vibration and the gradient angle of the rotor are measured until the rotor reaches to the end of the resonance state. Three dimensional numerical analysis of the flux which penetrates on the surface of the HTSC is undertaken. The relation between the dynamic characteristics and the flux is considered, and that of the hybrid system is compared with the non-hybrid one. In the hybrid system, the flux is changed by the influences of the stator side permanent magnet. Vibration and the gradient angle of the hybrid system are shown to be smaller than that of the non-hybrid one.

  10. High performance organic nonvolatile memory transistors based on HfO2 and poly(α-methylstyrene) electret hybrid charge-trapping layers

    Science.gov (United States)

    Xu, W. C.; He, H. X.; Jing, X. S.; Wu, S. J.; Zhang, Z.; Gao, J. W.; Gao, X. S.; Zhou, G. F.; Lu, X. B.; Liu, J.-M.

    2017-08-01

    In this work, we fabricated a high performance flash-type organic nonvolatile memory transistor, which adopted polymer-electret poly(α-methylstyrene) (PαMS) and HfO2 films as hybrid charge trapping layer (CTL). Compared with a single HfO2 or PαMS CTL structure, the hybrid HfO2/PαMS CTL structure can provide enhanced charge trapping efficiency to increase the device operation speed and reduce the leakage current to boost the device reliability. The fabricated nonvolatile organic memory transistors with the hybrid CTL shows excellent electrical properties, including low operation voltage (8 V), high speed (memories.

  11. Microstructured segmented Paul trap with tunable magnet field gradient; Mikrostrukturierte segmentierte Paul-Falle mit einstellbarem Magnetfeldgradienten

    Energy Technology Data Exchange (ETDEWEB)

    Kaufmann, Delia

    2012-02-03

    Strings of laser cooled ions stored in microstructured Paul traps (microtraps) have promising potential for quantum information science. They provide a system which can be screened from a decohering environment, accurately prepared, manipulated and state selectively detected with efficiency close to unity. Magnetic field gradients allow for addressing trapped ions in frequency space. Furthermore, coupling of the ions' motional and spin states and long range spin-spin coupling of the ions' internal states are induced by such a gradient. This method is called Magnetic Gradient Induced Coupling, MAGIC. In this thesis, the design, construction and first characterization of a novel microtrap with an integrated solenoid is reported. The solenoid is designed to create a high magnetic field gradient per dissipated heat. The microtrap consists of three layers stacked onto each other. The outer layers provide a trapping potential, while the inner layer creates the switchable magnetic field gradient. Another specialty of this trap is the 33 pairs of DC-electrodes, allowing to move the ions along the trap axis and to adjust the range and the strength of the ions' spin-spin interactions. The microtrap is fixed on top of a ceramic block that provides the necessary electrical connections via thick film printed wires, a technique adopted in the context of microtraps for the first time, and in addition acts as a vacuum interface. The volume of the vacuum chamber is quite small, allowing for pressures in the low 10{sup -11} mbar range. In this microtrap, {sup 172}Yb{sup +}-ions are trapped, cooled and shuttled over a distance of about 2 mm. Trapped ions are used as magnetic field gradient probes, with a relative magnetic field precision of {delta}B/B{sub 0}=7.10{sup -6}. The addressing of two ions with the MAGIC method in the solenoid's magnetic field gradient is demonstrated.

  12. Permanent magnet electron beam ion source/trap systems with bakeable magnets for improved operation conditions.

    Science.gov (United States)

    Schmidt, M; Zschornack, G; Kentsch, U; Ritter, E

    2014-02-01

    The magnetic system of a Dresden electron beam ion source (EBIS) generating the necessary magnetic field with a new type of permanent magnet made of high energy density NdFeB-type material operable at temperatures above 100 °C has been investigated and tested. The employment of such kind of magnets provides simplified operation without the time-consuming installation and de-installation procedures of the magnets for the necessary baking of the ion source after commissioning and maintenance work. Furthermore, with the use of a new magnetization technique the geometrical filling factor of the magnetic Dresden EBIS design could be increased to a filling factor of 100% leading to an axial magnetic field strength of approximately 0.5 T exceeding the old design by 20%. Simulations using the finite element method software Field Precision and their results compared with measurements are presented as well. It could be shown that several baking cycles at temperatures higher than 100 °C did not change the magnetic properties of the setup.

  13. A half-ring GMR sensor for detection of magnetic beads immobilized on a circular micro-trap

    KAUST Repository

    Gooneratne, Chinthaka Pasan

    2011-11-01

    Utilizing magnetic principles in biological immunoassays is an attractive option given its ability to remotely and non-invasively manipulate and detect cells tagged with micro/nano size superparamagnetic type beads and due to the fact that even the most complex biological immunoassays will have very little magnetic effect. The presence of magnetic beads can be detected by a magnetic sensor which quantifies the amount of target cells present in the immunoassay. In order to increase the detection rate a circular conducting micro-trap is employed to attract, trap and transport the magnetic beads to the sensing area. In this research we propose a half-ring spin valve type giant magnetoresistance (GMR) sensor for the measurement of stray fields produced by 2 μm magnetic beads which are around the circular micro-trap. A couple of half-ring GMR sensors can be used to cover the entire circular border width, in order to detect the majority of the immobilized magnetic beads. Analytical and numerical analysis leading towards the fabrication of the half-ring GMR sensor are presented. DC characterization of the fabricated sensor showed a magnetoresistance of 5.9 %. Experimental results showed that the half-ring GMR sensor detected the presence of 2 μm magnetic beads. Hence, half-ring GMR sensors integrated with a circular micro-trap have great potential to be used as an effective disease diagnostic device. © 2011 IEEE.

  14. 33. 6 T dc magnetic field produced in a hybrid magnet with Ho pole pieces

    Energy Technology Data Exchange (ETDEWEB)

    Rubin, L.G.; Brandt, B.L.; Weggel, R.J.; Foner, S.; McNiff E.J. Jr.

    1986-07-07

    A dc magnetic field of 33.6 +- 0.3 T was produced in a hybrid magnet whose central field was enhanced by a 3.5 T contribution from holmium pole pieces. The working (sample) volume was a 2-mm gap between the 19-mm-diam x 32-mm-long pole pieces tapered to 12-mm-diam faces. The magnetic field was measured with high-field/low-temperature Hall-effect sensors whose reproducibility and linearity made practical an extrapolation technique for fields above 30 T. Three superconducting samples with previously measured upper critical fields were used as calibration check points.

  15. Ambipolar transport via trapped-electron whistler instability along open magnetic field lines.

    Science.gov (United States)

    Guo, Zehua; Tang, Xian-Zhu

    2012-09-28

    An open field line plasma is bounded by a chamber wall which intercepts the magnetic field. Steady state requires an upstream plasma source balancing the particle loss to the boundary. In cases where the electrons have a long mean free path, ambipolarity in parallel transport critically depends on collisionless detrapping of the electrons via wave-particle interaction. The trapped-electron whistler instability, whose nonlinear saturation produces a spectrum of whistler waves that is responsible for the electron detrapping flux, is shown to be an unusually robust kinetic instability, which is essential to the universality of the ambipolar constraint in plasma transport.

  16. Coulomb scatter of diamagnetic dust particles in a cusp magnetic trap under microgravity conditions

    Energy Technology Data Exchange (ETDEWEB)

    Myasnikov, M. I., E-mail: miasnikovmi@mail.ru; D’yachkov, L. G.; Petrov, O. F.; Vasiliev, M. M., E-mail: mixxy@mail.ru; Fortov, V. E. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation); Savin, S. F.; Serova, E. O. [Korolev Rocket and Space Corporation Energia, ul. Lenina 4A (Russian Federation)

    2017-02-15

    The effect of a dc electric field on strongly nonideal Coulomb systems consisting of a large number (~10{sup 4}) of charged diamagnetic dust particles in a cusp magnetic trap are carried out aboard the Russian segment of the International Space Station (ISS) within the Coulomb Crystal experiment. Graphite particles of 100–400 μm in size are used in the experiments. Coulomb scatter of a dust cluster and the formation of threadlike chains of dust particles are observed experimentally. The processes observed are simulated by the molecular dynamics (MD) method.

  17. Pixel hybrid photon detector magnetic distortions characterization and compensation

    CERN Document Server

    Aglieri-Rinella, G; D'Ambrosio, Carmelo; Forty, Roger W; Gys, Thierry; Patel, Mitesh; Piedigrossi, Didier; Van Lysebetten, Ann

    2004-01-01

    The LHCb experiment requires positive kaon identification in the momentum range 2-100 GeV/c. This is provided by two ring imaging Cherenkov detectors. The stringent requirements on the photon detectors are fully satisfied by the novel pixel hybrid photon detector, HPD. The HPD is a vacuum tube with a quartz window, S20 photo-cathode, cross-focusing electron optics and a silicon anode encapsulated within the tube. The anode is a 32*256 pixels hybrid detector, with a silicon sensor bump-bonded onto a readout chip containing 8192 channels with analogue front-end and digital read-out circuitry. An external magnetic field influences the trajectory of the photoelectrons and could thereby degrade the inherent excellent space resolution of the HPD. The HPDs must be operational in the fringe magnetic field of the LHCb magnet. This paper reports on an extensive experimental characterization of the distortion effects. The characterization has allowed the development of parameterisations and of a compensation algorithm. ...

  18. Hybrid Method for 3D Segmentation of Magnetic Resonance Images

    Institute of Scientific and Technical Information of China (English)

    ZHANGXiang; ZHANGDazhi; TIANJinwen; LIUJian

    2003-01-01

    Segmentation of some complex images, especially in magnetic resonance brain images, is often difficult to perform satisfactory results using only single approach of image segmentation. An approach towards the integration of several techniques seems to be the best solution. In this paper a new hybrid method for 3-dimension segmentation of the whole brain is introduced, based on fuzzy region growing, edge detection and mathematical morphology, The gray-level threshold, controlling the process of region growing, is determined by fuzzy technique. The image gradient feature is obtained by the 3-dimension sobel operator considering a 3×3×3 data block with the voxel to be evaluated at the center, while the gradient magnitude threshold is defined by the gradient magnitude histogram of brain magnetic resonance volume. By the combined methods of edge detection and region growing, the white matter volume of human brain is segmented perfectly. By the post-processing using mathematical morphological techniques, the whole brain region is obtained. In order to investigate the validity of the hybrid method, two comparative experiments, the region growing method using only gray-level feature and the thresholding method by combining gray-level and gradient features, are carried out. Experimental results indicate that the proposed method provides much better results than the traditional method using a single technique in the 3-dimension segmentation of human brain magnetic resonance data sets.

  19. A hybrid data acquisition system for magnetic measurements of accelerator magnets

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X.; Hafalia, R.; Joseph, J.; Lizarazo, J.; Martchevsky, M.; Sabbi, G. L.

    2011-06-03

    A hybrid data acquisition system was developed for magnetic measurement of superconducting accelerator magnets at LBNL. It consists of a National Instruments dynamic signal acquisition (DSA) card and two Metrolab fast digital integrator (FDI) cards. The DSA card records the induced voltage signals from the rotating probe while the FDI cards records the flux increment integrated over a certain angular step. This allows the comparison of the measurements performed with two cards. In this note, the setup and test of the system is summarized. With a probe rotating at a speed of 0.5 Hz, the multipole coefficients of two magnets were measured with the hybrid system. The coefficients from the DSA and FDI cards agree with each other, indicating that the numerical integration of the raw voltage acquired by the DSA card is comparable to the performance of the FDI card in the current measurement setup.

  20. Pinning features of the magnetic flux trapped by YBCO single crystals in weak constant magnetic fields

    Science.gov (United States)

    Monarkha, V. Yu.; Paschenko, V. A.; Timofeev, V. P.

    2013-02-01

    The dynamics of Abrikosov vortices and their bundles was experimentally investigated in weak constant magnetic fields, in the range of Earth's magnetic field. Characteristics of the isothermal magnetization relaxation in YBCO single-crystal samples with strong pinning centers were studied for different sample-field orientation. The obtained values of normalized relaxation rate S allowed us to estimate the effective pinning potential U in the bulk of the YBCO sample and its temperature dependence, as well as the critical current density Jc. A comparison between the data obtained and the results of similar measurements in significantly higher magnetic fields was performed. To compare different techniques for evaluation of Jc, the magnetization loop measurements M(H), which relate the loop width to the critical current, were carried out. These measurements provided important parameters of the samples under study (penetration field Hp and first critical field Hc1), which involve the geometrical configuration of the samples.

  1. Significant flux trapping in single grain GdBCO bulk superconductor under off-axis field cooled magnetization

    Science.gov (United States)

    Li, Zhi; Ida, Tetsuya; Miki, Motohiro; Teshima, Hidekazu; Morita, Mitsuru; Izumi, Mitsuru

    2017-03-01

    A single grain bulk high-temperature superconductor (HTS) exhibits intensified flux trapping performance upon field cooled magnetization. The world record of trapped flux is 17.6 T achieved by using stacked two-fold GdBCO bulks. However, the majority of magnetization studies focused on the magnetization along the crystallographic c-axis. In the present study, we clarify the flux trapping performance under field cooled magnetization using an off-axis magnetic field with respect to the c-axis. The results show that the trapped flux is almost polarized along the applied field as expected. This tendency remains up to a high off-axis angle θ around 60°. It is worth mentioning that, with θ of 30°, the maximum trapped flux component B // max parallel to the c-axis significantly remains more than 96% of 1.6 T which occurs under on-axis magnetization. Meanwhile, the angular dependence of the c-axis parallel component exhibits that observed flux density is higher than that expected from 1.6 cosθ. In addition, to visualize the flux line upon magnetization at θ of 90°, we successfully demonstrate the continuous flux line trace using steel wires; different trapped flux behaviour appears when applied field penetrates the bulk through the growth sectors centre and along the growth sector boundary, respectively. We interpret these results may come from the microstructure as a result of melt growth. It is highly emphasized that the off-axis magnetization with the finite inclination angle is quite useful for introducing into the design of HTS applications.

  2. Particle Acceleration in Collapsing Magnetic Traps with a Braking Plasma Jet

    CERN Document Server

    Borissov, Alexei; Threlfall, James

    2016-01-01

    Collapsing magnetic traps (CMTs) are one proposed mechanism for generating non-thermal particle populations in solar flares. CMTs occur if an initially stretched magnetic field structure relaxes rapidly into a lower-energy configuration, which is believed to happen as a by-product of magnetic reconnection. A similar mechanism for energising particles has also been found to operate in the Earth's magnetotail. One particular feature proposed to be of importance for particle acceleration in the magnetotail is that of a braking plasma jet, i.e. a localised region of strong flow encountering stronger magnetic field which causes the jet to slow down and stop. Such a feature has not been included in previously proposed analytical models of CMTs for solar flares. In this work we incorporate a braking plasma jet into a well studied CMT model for the first time. We present results of test particle calculations in this new CMT model. We observe and characterise new types of particle behaviour caused by the magnetic stru...

  3. Impact of nitrogen doping of niobium superconducting cavities on the sensitivity of surface resistance to trapped magnetic flux

    Science.gov (United States)

    Gonnella, Dan; Kaufman, John; Liepe, Matthias

    2016-02-01

    Future particle accelerators such as the SLAC "Linac Coherent Light Source-II" (LCLS-II) and the proposed Cornell Energy Recovery Linac require hundreds of superconducting radio-frequency (SRF) niobium cavities operating in continuous wave mode. In order to achieve economic feasibility of projects such as these, the cavities must achieve a very high intrinsic quality factor (Q0) to keep cryogenic losses within feasible limits. To reach these high Q0's in the case of LCLS-II, nitrogen-doping of niobium cavities has been selected as the cavity preparation technique. When dealing with Q0's greater than 1 × 1010, the effects of ambient magnetic field on Q0 become significant. Here, we show that the sensitivity to RF losses from trapped magnetic field in a cavity's walls is strongly dependent on the cavity preparation. Specifically, standard electropolished and 120 °C baked cavities show a sensitivity of residual resistance from trapped magnetic flux of ˜0.6 and ˜0.8 nΩ/mG trapped, respectively, while nitrogen-doped cavities show a higher sensitivity of residual resistance from trapped magnetic flux of ˜1 to 5 nΩ/mG trapped. We show that this difference in sensitivities is directly related to the mean free path of the RF surface layer of the niobium: shorter mean free paths lead to less sensitivity of residual resistance to trapped magnetic flux in the dirty limit (ℓ ≪ ξ0), while longer mean free paths lead to lower sensitivity of residual resistance to trapped magnetic flux in the clean limit (ℓ ≫ ξ0). These experimental results are also shown to have good agreement with recent theoretical predictions for pinned vortex lines oscillating in RF fields.

  4. Coherent population trapping in diamond N-V centers at zero magnetic field.

    Science.gov (United States)

    Santori, Charles; Fattal, David; Spillane, Sean M; Fiorentino, Marco; Beausoleil, Raymond G; Greentree, Andrew D; Olivero, Paolo; Draganski, Martin; Rabeau, James R; Reichart, Patrick; Gibson, Brant C; Rubanov, Sergey; Jamieson, David N; Prawer, Steven

    2006-08-21

    Coherent population trapping at zero magnetic field was observed for nitrogen-vacancy centers in diamond under optical excitation. This was measured as a reduction in photoluminescence when the detuning between two excitation lasers matched the 2.88 GHz crystal-field splitting of the color center ground states. This behavior is highly sensitive to strain, which modifies the excited states, and was unexpected following recent experiments demonstrating optical readout of single nitrogen-vacancy electron spins based on cycling transitions. These results demonstrate for the first time that three-level Lambda configurations suitable for proposed quantum information applications can be realized simultaneously for all four orientations of nitrogen-vacancy centers at zero magnetic field.

  5. Countering the stray magnetic field of the CUSP trap by using additional coils

    CERN Document Server

    Thole, Jelle

    2016-01-01

    The ASACUSA experiment at the Antiproton Decelerator (AD) at CERN tries to measure the Hyperfine Structure (HFS) of Antihydrogen (H ̄) using a Rabi spectroscopy set-up. In measuring this HFS it will yield a very precise test of CPT-symmetry. For this set-up to work a homogeneous magnetic field is needed in the cavity where the Hyperfine transition of H ̄ occurs. Due to the stray fields from the CUSP trap, where H ̄ is produced, additional coils are needed to counter these fields. It is found, using COMSOL simulations, that two coils are suitable for this. Leading to a relative standard deviation of the magnetic field of σB/B = 1.06%.

  6. Control of light trapping in a large atomic system by a static magnetic field

    Science.gov (United States)

    Skipetrov, S. E.; Sokolov, I. M.; Havey, M. D.

    2016-07-01

    We propose to control light trapping in a large ensemble of cold atoms by an external, static magnetic field. For an appropriate choice of frequency and polarization of the exciting pulse, the field is expected to speed up the fluorescence of a dilute atomic system. In a dense ensemble, the field does not affect the early-time superradiant signal but amplifies intensity oscillations at intermediate times and induces a very slow, nonexponential long-time decay. The slowing down of fluorescence is due to the excitation of spatially localized collective atomic states that appear only under a strong magnetic field and have exponentially long lifetimes. Our results therefore pave a way towards experimental observation of the disorder-induced localization of light in cold atomic systems.

  7. Efficient light harvesting by photon downconversion and light trapping in hybrid ZnS nanoparticles/Si nanotips solar cells.

    Science.gov (United States)

    Huang, Chun-Ying; Wang, Di-Yan; Wang, Chun-Hsiung; Chen, Yung-Ting; Wang, Yaw-Tyng; Jiang, You-Ting; Yang, Ying-Jay; Chen, Chia-Chun; Chen, Yang-Fang

    2010-10-26

    A hybrid colloidal ZnS nanoparticles/Si nanotips p-n active layer has been demonstrated to have promising potential for efficient solar spectrum utilization in crystalline silicon-based solar cells. The hybrid solar cell shows an enhancement of 20% in the short-circuit current and approximately 10% in power conversion efficiency compared to its counterpart without integrating ZnS nanoparticles. The enhancement has been investigated by external quantum efficiency, photoluminescence excitation spectrum, photoluminescence, and reflectance to distinct the role of ZnS quantum dots for light harvesting. It is concluded that ZnS nanoparticles not only act as frequency downconversion centers in the ultraviolet region but also serve as antireflection coating for light trapping in the measured spectral regime. Our approach is ready to be extended to many other material systems for the creation of highly efficient photovoltaic devices.

  8. Improvement of the rotational characteristics in the HTSC-permanent magnet hybrid bearing using ring shaped magnet

    Science.gov (United States)

    Emoto, Kozo; Sugiyama, Ryo; Takagi, Shogo; Ohashi, Shunsuke

    2013-11-01

    We have developed the hybrid magnetic bearing using permanent magnets and the high-Tc bulk superconductor (HTSC). Pinning force of the HTSC is used for the levitation and the guidance. Repulsive force of the permanent magnets is introduced to increase the load weight of the magnetic bearing. In this system, the stator side permanent magnet has the ring type structure so that both pinning force and repulsive force are used effectively. In this paper, influence of the hybrid system on dynamic characteristics of the rotor is studied. The rotor which is supported by the hybrid magnetic bearing is rotated. Then, vibration and the gradient angle of the rotor are measured until the rotor reaches to the end of the resonance state. Three dimensional numerical analysis of the flux which penetrates on the surface of the HTSC is undertaken. The relation between the dynamic characteristics and the flux is considered, and that of the hybrid system is compared with the non-hybrid one. In the hybrid system, the flux is changed by the influences of the stator side permanent magnet. Vibration and the gradient angle of the hybrid system are shown to be smaller than that of the non-hybrid one.

  9. Improvement in field uniformity of the hybrid insert magnet

    Energy Technology Data Exchange (ETDEWEB)

    Asano, T; Yoshioka, H; Matsumoto, S; Kiyoshi, T [Tsukuba Magnet Laboratory, National Institute for Materials Science, Sakura 3-13, Tsukuba, Ibaraki 305-0003 (Japan)

    2006-11-15

    The hybrid magnet (HM) at the Tsukuba Magnet Laboratory (TML) generates 35 T in a 52-mm warm bore with a field uniformity of about 6500 ppm in a 10 mm diameter sphere volume (DSV). A new resistive insert magnet with the same bore was designed to provide the higher field uniformity in the HM operation and the construction was started. This e-magnet is composed of three concentric Bitter coils. The height of the outer coil is almost equal to that of present insert, . Tand the middle coil is made of a split-paired winding; . Tthe split gap is 53 mm. The A uniformity better than 10 ppm in a 10 mm DSV will be achieved at a themagnetic field of 34.0 T in a backup field of 14 T. This eimprovement in uniformity, in conjuncllaboration with the improvements of the DC power supply already in progress at the TML, will make it possible to expand the application fields of the HM of the TML.

  10. PIC numerical study of ECR plasmas confinement in a minimum-B and zero-B magnetic traps with GPU

    Science.gov (United States)

    Murillo Acevedo, M. T.; Dugar-Zhabon, V. D.

    2016-02-01

    This work analyzes through computational methods the phenomenon of confinement and heating of plasmas, in open magnetic traps, Minimum-B, and zero-B under conditions of resonance electron cyclotron (ECR). This simulation is made using electrostatic particle in cell method. First, it simulates the minimum-B trap, which has been studied both numerically and experimentally, by which is accomplished the confrontation of 6 different types of results that help us to validate our code. In the same way the zero-B trap is analysed. Proposed by Dr. Dugar-Zhabon, the main characteristic of the trap is the nullity of the magnetic field in the centre of the trap. The results show the detailed behaviour of the electronic component in the initial stage of the formation of plasma. Given the computational cost of the used model that allowed us to simulates fine details of the dynamics of plasma. Results were only reached in the time of half-life of the electrons. During this period the minimum-B trap proved to be better for the production of ions than the zero-B trap. Due to the huge amount of equations needed to solve the motion equations and the charge density, they are calculated in a Parallel way by GPU clustering.

  11. Preparation of Magnetic Hybrid Microspheres with Well-Defined Yolk-Shell Structure

    Directory of Open Access Journals (Sweden)

    Yuan Zhao

    2016-01-01

    Full Text Available A facile and efficient route was reported to prepare a kind of yolk-shell magnetic hybrid microspheres by suspension polymerization and calcinations method. The morphology, structure, and composition of the magnetic microspheres were characterized by FTIR, XRD, TEM, SEM, and TGA analysis. The vibrating-sample magnetometry (VSM results clearly showed that the magnetic particles were superparamagnetic with saturation magnetization of 32.82 emu/g which makes the microcomposites easily controlled by an external magnetic field. The results revealed that the magnetic hybrid microspheres might have important applications in magnetic bioseparation and drug delivery.

  12. The instability conditions of a weakly interacting Fermi gas trapped in weak magnetic field

    Institute of Scientific and Technical Information of China (English)

    Men Fu-Dian; Liu Hui

    2006-01-01

    In this paper the analytical expression of free energy expressed by small parameter r of a weakly interacting Fermi Based on the derived expression, the exact instability conditions of a weakly interacting Fermi gas trapped in weak magnetic field at both high and low temperatures are given. From the instability conditions we get the following two results. (1) At the whole low-temperature extent, whether the interactions are repulsive or attractive with (αn + 4εF/3)(n and εF denote the particle-number density and the Fermi energy respectively, c = 4πah2/m, and a is s-wave scattering length) positive, there is a lower-limit magnetic field of instability; in addition, there is an upper-limit magnetic field for the system of attractive interactions with (αn + 4eF/3) negative. (2) At the whole high-temperature extent, the system with repulsive interactions is always stable, but for the system with attractive interactions, the greater the scattering length of attractive interactions |a| is, the stronger the magnetic field is and the larger the particle-number density is,the bigger the possibility of instability in the system will be.

  13. Dust-acoustic solitary waves in a magnetized dusty plasma with nonthermal electrons and trapped ions

    CERN Document Server

    Misra, A P

    2014-01-01

    The nonlinear theory of electrostatic dust-acoustic (DA) waves in a magnetized dusty plasma consisting of negatively charged mobile dusts, nonthermal fast electrons and trapped ions with vortex-like distribution is revisited. Previous theory in the literature [Phys. Plasmas {\\bf 20}, 104505 (2013)] is rectified and put forward to include the effects of the external magnetic field, the adiabatic pressure of charged dusts as well as the obliqueness of propagation to the magnetic field. Using the reductive perturbation technique, a Korteweg-de Vries (KdV)-like equation is derived which governs the dynamics of the small-amplitude solitary waves in a magnetized dusty nonthermal plasma. It is found that due to the dust thermal pressure, there exists a critical value $(\\beta_c)$ of the nothermal parameter $\\beta (>1)$, denoting the percentage of energetic electrons, below which the DA solitary waves cease to propagate. The soliton solution (travelling wave) of the KdV-like equation is obtained, and is shown to be on...

  14. Trapped fields up to 2 T in a 12 mm square stack of commercial superconducting tape using pulsed field magnetization

    Science.gov (United States)

    Patel, A.; Hopkins, S. C.; Glowacki, B. A.

    2013-03-01

    The ability of superconductors to sustain persistent currents has been well exploited with (RE)BCO superconducting bulks, which can be magnetized to form a compact source of high magnetic field. However, thin films can also sustain persistent currents, which can be utilized by stacking them in layers to create a type of composite bulk. Such a stack is capable of trapping higher fields than a bulk, as reported in this paper. 12 mm wide, 55 μm thick commercial (RE)BCO tape from Superpower Inc was cut into 12 mm by 12 mm squares, stacked together and magnetized at temperatures between 10 and 77.4 K using a sequence of pulsed magnetic fields. The results are compared to a commercial 14 mm diameter YBCO bulk, showing that the stack of tapes outperformed the bulk at temperatures below approximately 60 K. Particularly high trapped fields were achieved below 50 K, with a maximum of 2.0 T at 10 K measured 0.8 mm from the stack surface. The maximum trapped field possible for a stack of tapes increases significantly with decreasing temperature down to 10 K, rather than saturating at a higher temperature as in the case of a bulk, due to superior thermal stability. The Jc, thermal and mechanical properties of commercial (RE)BCO tapes give them great potential for use as trapped field magnets activated by pulsed magnetic fields.

  15. A tubular hybrid Halbach/axially-magnetized permanent-magnet linear machine

    Directory of Open Access Journals (Sweden)

    Yi Sui

    2017-05-01

    Full Text Available A single-phase tubular permanent-magnet linear machine (PMLM with hybrid Halbach/axially-magnetized PM arrays is proposed for free-piston Stirling power generation system. Machine topology and operating principle are elaborately illustrated. With the sinusoidal speed characteristic of the free-piston Stirling engine considered, the proposed machine is designed and calculated by finite-element analysis (FEA. The main structural parameters, such as outer radius of the mover, radial length of both the axially-magnetized PMs and ferromagnetic poles, axial length of both the middle and end radially-magnetized PMs, etc., are optimized to improve both the force capability and power density. Compared with the conventional PMLMs, the proposed machine features high mass and volume power density, and has the advantages of simple control and low converter cost. The proposed machine topology is applicable to tubular PMLMs with any phases.

  16. A tubular hybrid Halbach/axially-magnetized permanent-magnet linear machine

    Science.gov (United States)

    Sui, Yi; Liu, Yong; Cheng, Luming; Liu, Jiaqi; Zheng, Ping

    2017-05-01

    A single-phase tubular permanent-magnet linear machine (PMLM) with hybrid Halbach/axially-magnetized PM arrays is proposed for free-piston Stirling power generation system. Machine topology and operating principle are elaborately illustrated. With the sinusoidal speed characteristic of the free-piston Stirling engine considered, the proposed machine is designed and calculated by finite-element analysis (FEA). The main structural parameters, such as outer radius of the mover, radial length of both the axially-magnetized PMs and ferromagnetic poles, axial length of both the middle and end radially-magnetized PMs, etc., are optimized to improve both the force capability and power density. Compared with the conventional PMLMs, the proposed machine features high mass and volume power density, and has the advantages of simple control and low converter cost. The proposed machine topology is applicable to tubular PMLMs with any phases.

  17. Dust-acoustic solitary waves in a magnetized dusty plasma with nonthermal electrons and trapped ions

    Science.gov (United States)

    Misra, A. P.; Wang, Yunliang

    2015-05-01

    The nonlinear propagation of electrostatic dust-acoustic (DA) waves in a magnetized dusty plasma consisting of negatively charged mobile dusts, nonthermal fast electrons and trapped ions with vortex-like distribution is studied. Using the reductive perturbation technique, a Korteweg-de Vries (KdV)-like equation is derived which governs the dynamics of the small-amplitude solitary waves in a magnetized dusty nonthermal plasma. It is found that due to the dust thermal pressure, there exists a critical value (βc) of the nonthermal parameter β (>1), denoting the percentage of energetic electrons, below which the DA solitary waves cease to propagate. The soliton solution (traveling wave) of the KdV-like equation is obtained, and is shown to be only of the rarefactive type. The properties of the solitons are analyzed numerically with the system parameters. It is also seen that the effect of the static magnetic field (which only modifies the soliton width) becomes significant when the dust gyrofrequency is smaller than one-tenth of the dust plasma frequency. Furthermore, the amplitude of the soliton is found to increase (decrease) when the ratio of the free to trapped ion temperatures (σ) is positive (negative). The effects of the system parameters including the obliqueness of propagation (lz) and σ on the dynamics of the DA solitons are also discussed numerically, and it is found that the soliton structures can withstand perturbations and turbulence during a considerable time. The results should be useful for understanding the nonlinear propagation of DA solitary waves in laboratory and space plasmas (e.g., Earth's magnetosphere, auroral region, heliospheric environments, etc.).

  18. A comparison of two magnetic ultra-cold neutron trapping concepts using a Halbach-octupole array

    CERN Document Server

    Leung, K; Martin, F; Rosenau, F; Simson, M; Zimmer, O

    2015-01-01

    This paper describes a new magnetic trap for ultra-cold neutrons (UCNs) made from a 1.2 m long Halbach-octupole array of permanent magnets with an inner bore radius of 47 mm combined with an assembly of superconducting end coils and bias field solenoid. The use of the trap in a vertical, magneto-gravitational and a horizontal setup are compared in terms of the effective volume and ability to control key systematic effects that need to be addressed in high precision neutron lifetime measurements.

  19. Observations of flux motion in niobium films. [study of magnetic field trapped in superconducting coatings of gyroscope rotor

    Science.gov (United States)

    Xiao, Y. M.; Keiser, G. M.

    1991-01-01

    A magnetic field trapped in a superconducting sphere was examined at temperatures from 4.6 K to 5.5 K. The sphere was the rotor of a precision gyroscope and was made of fused quartz and coated with a sputtered niobium film. The rotor diameter was 3.8 cm. The film thickness was 2.5 microns. The tests were carried out at an ambient magnetic field of about 1 mG. Unexpected instability of the trapped field was observed. The experimental results and possible explanations are presented.

  20. Semiconductor/Piezoelectrics Hybrid Heterostructures with Highly Effective Gate-Tunable Electrotransport and Magnetic Behaviors.

    Science.gov (United States)

    Chen, Lei; Zhao, Wei-Yao; Wang, Jing; Gao, Guan-Yin; Zhang, Jin-Xing; Wang, Yu; Li, Xiao-Min; Cao, Shi-Xun; Li, Xiao-Guang; Luo, Hao-Su; Zheng, Ren-Kui

    2016-10-12

    We report the epitaxial growth of oxygen deficient titanium dioxide thin films on 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 (PMN-PT) single crystals and realized highly effective in situ electrostatic manipulation of electrotransport and magnetism of TiO2-δ films via gate voltages. Upon the polarization switching in the PMN-PT, the carrier density of the TiO2-δ film could be reversibly modified, resulting in a large nonvolatile resistivity modulation by ∼51% at T = 300 K, approximately 4-12 times larger than that of other transition-metal oxide film/PMN-PT structures. By taking advantage of in situ manipulation of the carrier density via gate voltages, we found that competition between the trap of electrons by the Ti(3+)-VO pairs and that by the positive polarization charges at the interface results in a significant resistivity relaxation upon the polarization switching, and revealed that magnetization is inversely correlated with the carrier density of the TiO2-δ film. Such hybrid structures combining materials with dissimilar functionalities may have potential applications in multifunctional devices which can take advantage of the useful and unique properties of both materials.

  1. Hybrid magnetic – Semiconductor nanocomposites: optical, magnetic and nanosecond dynamical properties

    Energy Technology Data Exchange (ETDEWEB)

    Emam, A.N.; Girgis, E.; Mostafa, A.A. [National Research Center, Dokki, Giza (Egypt); Guirguis, O.W. [Biophysics Department, Faculty of Science, Cairo University, Giza (Egypt); Mohamed, M.B., E-mail: monabmohamed@gmail.com [National Institute of Laser Enhanced Science, Cairo University, Giza (Egypt); NanoTech Egypt for Photoelectronics, Dreamland, Giza (Egypt)

    2015-07-15

    A series of colloidal CdSe quantum dots doped with different concentration of cobalt ions has been prepared via organometallic pyrolysis of a mixture of cadmium stearate and cobalt dithiocarbazate. The conditions required for successful doping depend on the source of cobalt ions and the dopant concentration. The structure and morphology of the prepared nanocrystals have been characterized using X-Ray Diffraction (XRD), and Transmission Electron Microscope (TEM). Slight shift in the interplaner space was observed in the XRD pattern of the doped nanocrystals. Formation of separate cobalt nanoclusters has been observed in the TEM images upon increasing the cobalt concentration more than 2% of the original cadmium concentration. This was confirmed by magnetic measurements of the prepared samples. Room-temperature ferromagnetism has been observed, in which the switching field increases as the cobalt ratio increases. Increasing the cobalt ratio more than 5% increases the coercivity due to formation of Co{sup 0} nanoclusters. Moreover, the presence of localized magnetic ions in semiconductor QDs leads to strong exchange interactions between sp band electrons and the magnetic ions d electrons. This would influence the optical properties such as absorption, emission, as well as nanosecond relaxation dynamics. - Graphical abstract: Display Omitted - Highlights: • Hybrid semiconductor-magnetic nanostructure was prepared via chemical method. • Room-temperature ferromagnetism for hybrid CdSe–Co quantum dots has been observed. • Co{sup +2} ions induces slight shift in the interplaner space distance of the doped QDs. • Hybrid CdSe–Co QDs have better quantum yield than pure CdSe QDs. • Hybrid CdSe–Co nanocrystals have faster electron-hole dynamics than pure CdSe QDs.

  2. A Novel Integral 5-DOFs Hybrid Magnetic Bearing with One Permanent Magnet Ring Used for Turboexpander

    Directory of Open Access Journals (Sweden)

    Bangcheng Han

    2014-01-01

    Full Text Available We propose a novel combined five-degrees-of-freedom (5-DOFs hybrid magnetic bearing (HMB with only one permanent magnet ring (PMR used for turboexpanders. It has two radial magnetic bearing (RMB units; each has four poles and one thrust magnetic bearing (TMB to control 5-DOFs. Based on one PMR, the bias flux of the two radial magnetic bearing units and the one thrust magnetic bearing unit is constructed. As a result, ultra-high-speed, lower power loss, small size, and low cost can be achieved. Furthermore, the equivalent magnetic circuit method and 3D finite element method (FEM are used to model and analyze the combined 5-DOFs HMB. The force-current, force-position, torque-coil currents, the torque-angle position, and the stiffness models of the combined 5-DOFs HMB are given. Moreover, its coupling problems between the RMB units and the AMB unit are also proposed in this paper. An example is given to clarify the mathematical models and the coupling problems, and the linearized models are proposed for the follow-up controller design.

  3. Basic Characteristics of the Propulsion System in the Permanent Magnet-HTSC Hybrid Magnetic Conveyance System

    Science.gov (United States)

    Ohashi, Shunsuke; Kumano, Daiki; Goto, Yasuyuki

    The Hybrid magnetically levitated transportation system has been developed. The magnetic rail is set on the ground, and the carrier with permanent magnets and high-Tc superconductors (HTSC) levitates on the rail. Repulsive force of permanent magnet is introduced to support load weight. Pinning force of the HTSC is used to support weight of the frame of the carrier and to achieve lateral stability of the carrier. In this paper, propulsion system of the conveyance system is studied. Propulsion function is installed on the carrier body. Magnetic gradient is used to get propulsion force. Propulsion force of the system is little. So propulsion rail system is introduced. Air core copper coils are installed on the magnetic rail. Interaction between current of these coils and permanent magnets on the carrier generates propulsion force. Enough propulsion force is given. Influence of the propulsion system on the levitation and guidance system is measured. Stability of levitation and guidance system is enough even when propulsion system is operated.

  4. Thermometry of levitated nanoparticles in a hybrid electro-optical trap

    Science.gov (United States)

    Aranas, E. B.; Fonseca, P. Z. G.; Barker, P. F.; Monteiro, T. S.

    2017-03-01

    There have been recent rapid developments in stable trapping of levitated nanoparticles in high vacuum. Cooling of nanoparticles, from phonon occupancies of 107 down to ≃ 100{--}1000 phonons, have already been achieved by several groups. Prospects for quantum ground-state cooling seem extremely promising. Cavity-cooling without added stabilisation by feedback cooling remains challenging, but trapping at high vacuum in a cavity is now possible through the addition of a Paul trap. However, the Paul trap has been found to qualitatively modify the cavity output spectrum, with the latter acquiring an atypical ‘split-sideband’ structure, of different form from the displacement spectrum, and which depends on N, the optical well at which the particle localises. In the present work we investigate the N-dependence of the dynamics, in particular with respect to thermometry: we show that in strong cooling regions N≳ 100, the temperature may still be reliably inferred from the cavity output spectra. We also explain the N-dependence of the mechanical frequencies and optomechanical coupling showing that these may be accurately estimated. We present a simple ‘fast-cavity’ model for the cavity output and test all our findings against full numerical solutions of the nonlinear stochastic equations of motion for the system.

  5. Avalanche boron fusion by laser picosecond block ignition with magnetic trapping for clean and economic reactor

    CERN Document Server

    Hora, H; Eliezer, S; Lalousis, N Nissim P; Giuffrida, L; Margarone, D; Picciotto, A; Miley, G H; Moustaizis, S; Martinez-Val, J -M; Barty, C P J; Kirchhoff, G J

    2016-01-01

    After the very long consideration of the ideal energy source by fusion of the protons of light hydrogen with the boron isotope 11 (boron fusion HB11) the very first two independent measurements of very high reaction gains by lasers basically opens a fundamental breakthrough. The non-thermal plasma block ignition with extremely high power laser pulses above petawatt of picosecond duration in combination with up to ten kilotesla magnetic fields for trapping has to be combined to use the measured high gains as proof of an avalanche reaction for an environmentally clean, low cost and lasting energy source as potential option against global warming. The unique HB11 avalanche reaction is are now based on elastic collisions of helium nuclei (alpha particles) limited only to a reactor for controlled fusion energy during a very short time within a very small volume.

  6. Trapping neutral particles endowed with a magnetic moment by an electromagnetic wave carrying orbital angular momentum: Semiclassical theory

    CERN Document Server

    Bialynicki-Birula, Iwo

    2016-01-01

    The motion of a neutral atom endowed with a magnetic moment interacting with the magnetic field is determined from the Ehrenfest-like equations of motion. These equations for the average values of the translational and spin degrees of freedom are derived from the Schr\\"odinger-Pauli wave equation and they form a set of nine coupled nonlinear evolution equations. The numerical and analytic solutions of these equations are obtained for the combination of the rotating magnetic field of a wave carrying orbital angular momentum and a static magnetic field. The running wave traps the atom only in the transverse direction while the standing wave traps the atom also in the direction of the beam.

  7. Flywheel Energy Storage System Suspended by Hybrid Magnetic Bearing

    Science.gov (United States)

    Owusu-Ansah, Prince; Hu, Yefa; Misbawu, Adam

    This work presents a prototype flywheel energy storage system (FESS) suspended by hybrid magnetic bearing (HMB) rotating at a speed of 20000rpm with a maximum storage power capacity of 30W with a maximum tip speed of 300m/s. The design presented is an improvement of most existing FESS, as the design incorporates a unique feature in that the upper and the lower rotor and stator core are tapered which enhances larger thrust and much lower radial force to be exerted on the system. Without any adverse effect being experienced by the model. The work also focuses on the description of developing a prototype FESS suspended by HMB using solid works as a basis of developing in the nearer future a more improved FESS suspended by HMB capable of injecting the ever increasing high energy demand situation in the 21st century and beyond.

  8. Cryogenic Design of the 43 T LNCMI Grenoble Hybrid Magnet

    Science.gov (United States)

    Hervieu, B.; Berriaud, Ch.; Berthier, R.; Debray, F.; Fazilleau, Ph.; Manil, P.; Massinger, M.; Pfister, R.; Pugnat, P.; Ronayette, L.; Trophime, C.

    The association of two inner resistive coils (Polyhelix and Bitter) producing 34.5 T with an outer NbTi superconducting coil producing 8.5 T to obtain a 43 T hybrid magnet is a technical challenge. Accidental failure modes leading to complex electromagnetic behaviors and large transient dynamical forces should be anticipated. These considerations lead to a reinforced design and a thermo-hydraulic strategy to limit the overpressure. The cryostat has been designed with innovative thermo-mechanical supports sustaining the coil at 1.8 K-1200 hPa and the eddy current shield at 30 K, both being possibly overloaded by high dynamic forces in the worst accidental failure case.

  9. Hybrid Magnetic Core-Shell Nanophotocatalysts for Environmental Applications

    Energy Technology Data Exchange (ETDEWEB)

    Gaulden, Patrick [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Murph, Simona Hunyadi [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Univ. of Georgia, Athens, GA (United States). Dept. of Physics and Astronomy

    2016-07-29

    This research study describes a facile sol-gel method to creating hybrid iron (III) oxide/silica/titania nanomaterials decorated with gold nanoparticles for use in environmental applications. The multi-functional composition of the nanomaterials allows for photocatalyzed reactions to occur in both the visible and the UV range. The morphologies, elemental composition, and surface charge of the nanoparticles were determined by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), and Phase Analysis Light Scattering (PALS), respectively. The photocatalytic activity of the synthesized hybrid nanoparticles for breaking down a model analyte, methyl orange (MO), was then evaluated using UV-Vis Spectroscopy. The efficiency of the photocatalyst under UV light irradiation was measured and compared to other well-studied nanophotocatalysts, namely titanium oxide and iron oxide nanoparticles. The concentration dependence of both the photocatalyst and the analyte was also investigated. By utilizing the known UV-active properties of TiO2, the magnetic properties of Fe2O3, the optical properties of gold in the visible range of the spectrum, and the high stability of silica, a novel, highly efficient photocatalyst that is active on a broad range of the spectrum (UV-Vis) can be created to destroy organic pollutants in wastewater streams.

  10. Classification of magnetic inhomogeneities and 0 -π transitions in superconducting-magnetic hybrid structures

    Science.gov (United States)

    Baker, Thomas E.; Richie-Halford, Adam; Bill, Andreas

    2016-09-01

    We present a comparative study of pair correlations and currents through superconducting-magnetic hybrid systems with a particular emphasis on the tunable Bloch domain wall of an exchange spring. This study of the Gor'kov functions contrasts magnetic systems with domain walls that change at discrete points in the magnetic region with those that change continuously throughout. We present results for misaligned homogeneous magnetic multilayers, including spin valves, for discrete domain walls, as well as exchange springs and helical domain walls—such as Holmium—for the continuous case. Introducing a rotating basis to disentangle the role of singlet and triplet correlations, we demonstrate that substantial amounts of (so-called short-range) singlet correlations are generated throughout the magnetic system in a continuous domain wall via the cascade effect. We propose a classification of 0 -π transitions of the Josephson current into three types, according to the predominant pair correlations symmetries involved in the current. Properties of exchange springs for an experimental study of the proposed effects are discussed. The interplay between components of the Gor'kov function that are parallel and perpendicular to the local magnetization lead to a novel prediction about their role in a proximity system with a progressively twisting helix that is experimentally measurable.

  11. Towards hybrid quantum systems: Trapping a single atom near a nanoscale solid-state structure

    Directory of Open Access Journals (Sweden)

    Tiecke T.G.

    2013-08-01

    Full Text Available We describe and demonstrate a method to deterministically trap single atoms near nanoscale solid-state objects. The trap is formed by the interference of an optical tweezer and its reflection from the nano object, creating a one-dimensional optical lattice where the first lattice site is at z0 ∼ λ/4 from the surface. Using a tapered optical fiber as the nanoscopic object, we characterize the loading into different lattice sites by means of the AC-Stark shift induced by a guided fiber mode. We demonstrate a loading efficiency of 94(6% into the first lattice site, and measure the cooperativity for the emission of the atom into the guided mode of the nanofiber. We show that by tailoring the dimensions of the nanofiber the distance of the trap to the surface can be adjusted. This method is applicable to a large variety of nanostructures and represents a promising starting point for interfacing single atoms with arbitrary nanoscale solid-state systems.

  12. Recent Advances of Graphene-based Hybrids with Magnetic Nanoparticles for Biomedical Applications.

    Science.gov (United States)

    Alegret, Nuria; Criado, Alejandro; Prato, Maurizio

    2017-01-01

    The utilization of graphene-based nanomaterials combined with magnetic nanoparticles offers key benefits in the modern biomedicine. In this minireview, we focus on the most recent advances in hybrids of magnetic graphene derivatives for biomedical applications. We initially analyze the several methodologies employed for the preparation of graphene-based composites with magnetic nanoparticles, more specifically the kind of linkage between the two components. In the last section, we focus on the biomedical applications where these magnetic-graphene hybrids are essential and pay special attention on how the addition of graphene improves the resulting devices in magnetic resonance imaging, controlled drug delivery, magnetic photothermal therapy and cellular separation and isolation. Finally, we highlight the use of these magnetic hybrids as multifunctional material that will lead to a next generation of theranostics. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  13. Optical cooling and trapping of highly magnetic atoms: the benefits of a spontaneous spin polarization

    Science.gov (United States)

    Dreon, Davide; Sidorenkov, Leonid A.; Bouazza, Chayma; Maineult, Wilfried; Dalibard, Jean; Nascimbene, Sylvain

    2017-03-01

    From the study of long-range-interacting systems to the simulation of gauge fields, open-shell lanthanide atoms with their large magnetic moment and narrow optical transitions open novel directions in the field of ultracold quantum gases. As for other atomic species, the magneto-optical trap (MOT) is the working horse of experiments but its operation is challenging, due to the large electronic spin of the atoms. Here we present an experimental study of narrow-line dysprosium MOTs. We show that the combination of radiation pressure and gravitational forces leads to a spontaneous polarization of the electronic spin. The spin composition is measured using a Stern–Gerlach separation of spin levels, revealing that the gas becomes almost fully spin-polarized for large laser frequency detunings. In this regime, we reach the optimal operation of the MOT, with samples of typically 3× {10}8 atoms at a temperature of 15 μK. The spin polarization reduces the complexity of the radiative cooling description, which allows for a simple model accounting for our measurements. We also measure the rate of density-dependent atom losses, finding good agreement with a model based on light-induced Van der Waals forces. A minimal two-body loss rate β ∼ 2× {10}-11 cm3 s–1 is reached in the spin-polarized regime. Our results constitute a benchmark for the experimental study of ultracold gases of magnetic lanthanide atoms.

  14. Electron Cloud Generation and Trapping in a Quadrupole Magnet at the Los Alamos Proton Storage Ring

    Energy Technology Data Exchange (ETDEWEB)

    Macek, Robert J.; Browman, Andrew A.; Ledford, John E.; /TechSource, Santa Fe /Los Alamos; Borden, Michael J.; O' Hara, James F.; McCrady, Rodney C.; Rybarcyk, Lawrence J.; Spickermann, Thomas; Zaugg, Thomas J.; /Los Alamos; Pivi, Mauro T.F.; /SLAC

    2008-03-17

    Recent beam physics studies on the two-stream e-p instability at the LANL proton storage ring (PSR) have focused on the role of the electron cloud generated in quadrupole magnets where primary electrons, which seed beam-induced multipacting, are expected to be largest due to grazing angle losses from the beam halo. A new diagnostic to measure electron cloud formation and trapping in a quadrupole magnet has been developed, installed, and successfully tested at PSR. Beam studies using this diagnostic show that the 'prompt' electron flux striking the wall in a quadrupole is comparable to the prompt signal in the adjacent drift space. In addition, the 'swept' electron signal, obtained using the sweeping feature of the diagnostic after the beam was extracted from the ring, was larger than expected and decayed slowly with an exponential time constant of 50 to 100 {micro}s. Other measurements include the cumulative energy spectra of prompt electrons and the variation of both prompt and swept electron signals with beam intensity. Experimental results were also obtained which suggest that a good fraction of the electrons observed in the adjacent drift space for the typical beam conditions in the 2006 run cycle were seeded by electrons ejected from the quadrupole.

  15. Hybrid (particle in cell-fluid) simulation of ion-acoustic soliton generation including super-thermal and trapped electrons

    Energy Technology Data Exchange (ETDEWEB)

    Nopoush, M.; Abbasi, H. [Faculty of Physics, Amirkabir University of Technology, P. O. Box 15875-4413, Tehran (Iran, Islamic Republic of)

    2011-08-15

    The present paper is devoted to the simulation of the nonlinear disintegration of a localized perturbation into an ion-acoustic soliton in a plasma. Recently, this problem was studied by a simple model [H. Abbasi et al., Plasma Phys. Controlled Fusion 50, 095007 (2008)]. The main assumptions were (i) in the electron velocity distribution function (DF), the ion-acoustic soliton velocity was neglected in comparison to the electron thermal velocity, (ii) on the ion-acoustic evolution time-scale, the electron velocity DF was assumed to be stationary, and (iii) the calculation was restricted to the small amplitude case. In order to generalize the model, one has to consider the evolution of the electron velocity DF for finite amplitudes. For this purpose, a one dimensional electrostatic hybrid code, particle in cell (PIC)-fluid, was designed. It simulates the electrons dynamics by the PIC method and the cold ions dynamics by the fluid equations. The plasma contains a population of super-thermal electrons and, therefore, a Lorentzian (kappa) velocity DF is used to model the high energy tail in the electron velocity DF. Electron trapping is included in the simulation in view of their nonlinear resonant interaction with the localized perturbation. A Gaussian initial perturbation is used to model the localized perturbation. The influence of both the trapped and the super-thermal electrons on this process is studied and compared with the previous model.

  16. Assessment of Rock Magnetic Parameters for Fly Ash Pollution Screening in Topsoil of the Deccan Trap Basalt Area, India

    Science.gov (United States)

    Blaha, U.; Basavaiah, N.; Das, P. K.; Deenadayalan, K.

    2012-04-01

    Rock magnetic parameters of highly magnetic topsoil of the Deccan Trap basalt area are evaluated for their suitability for efficient environmental magnetic pollution screening. Parameters, such as magnetic susceptibility (χ), frequency dependence of magnetic susceptibility (κ fd%), anhysteretic remanent magnetization (ARM), saturation isothermal remanent magnetization (SIRM), soft isothermal remanent magnetization (Soft IRM), as well as thermo-magnetic analysis (κ-T) are compared and assessed for best depiction of topsoil contamination due to ash deposition around the Nashik thermal power station (NTPS). Fifty-five topsoil samples, collected along north-south and west-east stretching transects of 24 km length, are the basis for evaluation of the specific ash distribution pattern around the plant and its adjacent ash pond. Similar decline of the magnetic signals with increasing distance from the point source is observed in the concentration dependent magnetic parameters and can be modeled. The magnetic grain size parameters instead reveal increasing trends with increasing distance. Verwey-transition and Hopkinson peak obtained from κ-T analyses demonstrate to be important parameters to prove fly ash accumulation in soils of basaltic origin. The importance of magnetic parameters for indirect tracing of pollutants, such as heavy metals, is shown by Pb, Zn and Cu data, revealing similar distribution pattern as obtained from the concentration dependent magnetic parameters. Confirmation of the presence of a very high amount of ash particles in the vicinity of the NTPS and a low number of particles in more distant areas is provided by scanning electron microscopy (SEM) on quantitatively extracted magnetic particles at 5.5 km and 11.9 km distance in eastern direction. The investigation demonstrates that the majority of the rock magnetic parameters has the potential to be successfully applied in environmental magnetic studies in areas with high magnetic background

  17. Measurement of Absolute Atomic Collision Cross Section with Helium Using 87Rb Atoms Confined in Magneto-Optic and Magnetic Traps

    Institute of Scientific and Technical Information of China (English)

    WANG Ji-Cheng; ZHOU Ke-Ya; WANG Yue-Yuan; LIAO Qing-Hong; LIU Shu-Tian

    2011-01-01

    We present the measurements and calculations of the absolute total collision cross sections for a room-temperature gas of helium using 87 Rb atoms confined in either a magneto-optic or a magnetic quadrupole trap. The loss rates from the magneto-optic trap and the pure magnetic trap are compared and show significant differences. The collision cross sections as a function of trap depth for helium gas are obtained. These findings are significant for extracting the information about the different cross sections when the trap depth is changed.%@@ We present the measurements and calculations of the absolute total collision cross sections for a room-temperature gas of helium using 87Rb atoms confined in either a magneto-optic or a magnetic quadrupole trap.The loss rates from the magneto-optic trap and the pure magnetic trap are compared and show significant differences.The collision cross sections as a function of trap depth for helium gas are obtained.These findings are significant for extracting the information about the different cross sections when the trap depth is changed.

  18. Levitation and Guidance Characteristics of the Permanent magnet-HTSC Hybrid Magnetic Conveyance System

    Science.gov (United States)

    Ohashi, Shunsuke; Dodo, Daiki

    Hybrid magnetically levitated transportation system has been developed. The magnetic rail is set on the ground, and the carrier with permanent magnets and high-Tc superconductors (HTSC) levitates on the rail. In this system, pinning force of HTSC and repulsive force of permanent magnet is combined. Repulsive force of permanent magnet is introduced to support weight. Pinning force is used to support weight of the frame of the carrier and to achieve lateral stability of the carrier. To decrease influence of weight on the levitation gap of the carrier, the weight stage is fixed to the carrier frame by linear sliders, and moves freely for vertical direction. As a result, there is little influence on levitation gap of the carrier. Basic levitation and guidance characteristics of the system are shown. Repulsive force generates very large levitation force. It also generates unstable lateral force. Weight added to the carrier has some influence on lateral stability. Although lateral position recovery force by pinning effect decreases at a heavier weight, the carrier shows enough force to keep lateral stability.

  19. Generation of spin polarized currents with coherent trapping in magnetic semiconductors

    Science.gov (United States)

    Pereira, Pedro H.; Bezerra, Anibal T.; Farinas, Paulo F.; Maialle, Marcelo Z.; Degani, Marcos H.; Studart, Nelson

    2017-04-01

    A semiconductor heterostructure consisting of two quantum wells, one of them magnetically doped, is proposed for the generation of spin currents by two lasers tuned at the resonances formed between two lowest energy states (1 and 2) and the continuum (3), which are set by design to be in a Λ like configuration. By numerically simulating the proposed structure under the action of the laser fields, we are able to observe the formation of a quasi-dark state near the resonance. The structure’s design has been idealized as to place state 2 in the magnetically doped quantum-well, where a constant magnetic field breaks the electronic spin degeneracy, leading to the giant Zeeman splitting. This ensures that only one of the electronic spins is driven into a dark resonance, thus blocking it from escaping the system. The other spin is free to escape, so that a spin polarized photocurrent is generated. The polarization can be switched by changing the frequency of the controlling laser. Since this kind of trapping is based on quantum interference, the switching times are expected to be fast. In our simulation, we do not simplify the structure down to level modeling, rather we simulate the full structure under time dependent oscillating laser fields and then identify the signatures that indicate a three-level like behavior. We based our search for the structure on real doping parameters found in real materials used in the literature, however the idea relies on the potential profiles studied, and the presence of the giant splitting, regardless of the underlying material that may be used.

  20. Anisotropic Thermal Properties of Nanostructured Magnetic, Carbon and Hybrid Magnetic - Carbon Materials

    Science.gov (United States)

    Ramirez, Sylvester

    In this dissertation research we investigated thermal properties of three groups of nanostructured materials: (i) magnetic; (ii) reduced graphene oxide films; and (iii) hybrid magnetic -- graphite -- graphene composites. The thermal measurements were conducted using the transient "hot disk" and "laser flash" techniques. The rare-earth free nanostructured SrFe12O19 permanent magnets were produced by the current activated pressure assisted densification technique. The thermal conductivity of the nanostructured bulk magnets was found to range from 3.8 to 5.6 W/mK for the in-plane and 2.36 W/mk to 2.65 W/mK for the cross-plane directions, respectively. The heat conduction was dominated by phonons near the room temperature. The anisotropy of heat conduction was explained by the brick-like alignment of crystalline grains with the longer grain size in-plane direction. The thermal conductivity scales up with the average grain size and mass density of the material revealing weak temperature dependence. Using the nanostructured ferromagnetic Fe3O4 composites as an example system, we incorporated graphene and graphite fillers into magnetic material without changing their morphology. It was demonstrated that addition of 5 wt. % of equal mixture of graphene and graphite flakes to the composite results in a factor of x2.6 enhancement of the thermal conductivity without significant degradation of the saturation magnetization. We investigated thermal conductivity of free-standing reduced graphene oxide films subjected to a high-temperature treatment of up to 1000°C. It was found that the high-temperature annealing dramatically increased the in-plane thermal conductivity, K, of the films from ˜3 W/mK to ˜61 W/mK at room temperature. The cross-plane thermal conductivity, K⊥, revealed an interesting opposite trend of decreasing to a very small value of ˜0.09 W/mK in the reduced graphene oxide films annealed at 1000°C. The obtained films demonstrated an exceptionally strong

  1. Reversible photo-induced trap formation in mixed-halide hybrid perovskites for photovoltaics.

    Science.gov (United States)

    Hoke, Eric T; Slotcavage, Daniel J; Dohner, Emma R; Bowring, Andrea R; Karunadasa, Hemamala I; McGehee, Michael D

    2015-01-01

    We report on reversible, light-induced transformations in (CH3NH3)Pb(Br x I1-x )3. Photoluminescence (PL) spectra of these perovskites develop a new, red-shifted peak at 1.68 eV that grows in intensity under constant, 1-sun illumination in less than a minute. This is accompanied by an increase in sub-bandgap absorption at ∼1.7 eV, indicating the formation of luminescent trap states. Light soaking causes a splitting of X-ray diffraction (XRD) peaks, suggesting segregation into two crystalline phases. Surprisingly, these photo-induced changes are fully reversible; the XRD patterns and the PL and absorption spectra revert to their initial states after the materials are left for a few minutes in the dark. We speculate that photoexcitation may cause halide segregation into iodide-rich minority and bromide-enriched majority domains, the former acting as a recombination center trap. This instability may limit achievable voltages from some mixed-halide perovskite solar cells and could have implications for the photostability of halide perovskites used in optoelectronics.

  2. Hybrid magnet devices for molecule manipulation and small scale high gradient-field applications

    Science.gov (United States)

    Humphries, David E.; Hong, Seok-Cheol; Cozzarelli, legal representative, Linda A.; Pollard, Martin J.; Cozzarelli, Nicholas R.

    2009-01-06

    The present disclosure provides a high performance hybrid magnetic structure made from a combination of permanent magnets and ferromagnetic pole materials which are assembled in a predetermined array. The hybrid magnetic structure provides means for separation and other biotechnology applications involving holding, manipulation, or separation of magnetizable molecular structures and targets. Also disclosed are hybrid magnetic tweezers able to exert approximately 1 nN of force to 4.5 .mu.m magnetic bead. The maximum force was experimentally measured to be .about.900 pN which is in good agreement with theoretical estimations and other measurements. In addition, a new analysis scheme that permits fast real-time position measurement in typical geometry of magnetic tweezers has been developed and described in detail.

  3. Appropriate choice of collision-induced dissociation energy for qualitative analysis of notoginsenosides based on liquid chromatography hybrid ion trap time-of-flight mass spectrometry.

    Science.gov (United States)

    Wang, Guang-Ji; Fu, Han-Xu; Xiao, Jing-Cheng; Ye, Wei; Rao, Tai; Shao, Yu-Hao; Kang, Dian; Xie, Lin; Liang, Yan

    2016-04-01

    Liquid chromatography hybrid ion trap/time-of-flight mass spectrometry possessesd both the MS(n) ability of ion trap and the excellent resolution of a time-of-flight, and has been widely used to identify drug metabolites and determine trace multi-components for in natural products. Collision energy, one of the most important factors in acquiring MS(n) information, could be set freely in the range of 10%-400%. Herein, notoginsenosides were chosen as model compounds to build a novel methodology for the collision energy optimization. Firstly, the fragmental patterns of the representatives for the authentic standards of protopanaxadiol-type and protopanaxatriol-type notoginsenosides authentic standards were obtained based on accurate MS(2) and MS(3) measurements via liquid chromatography hybrid ion trap/time-of-flight mass spectrometry. Then the extracted ion chromatograms of characteristic product ions of notoginsenosides in Panax Notoginseng Extract, which were produced under a series of collision energies and, were compared to screen out the optimum collision energies values for MS(2) and MS(3). The results demonstrated that the qualitative capability of liquid chromatography hybrid ion trap/time-of-flight mass spectrometry was greatly influenced by collision energies, and 50% of MS(2) collision energy was found to produce the highest collision-induced dissociation efficiency for notoginsenosides. BesidesAddtionally, the highest collision-induced dissociation efficiency appeared when the collision energy was set at 75% in the MS(3) stage.

  4. Magnetic field mapping of the UCNTau magneto-gravitational trap: design study

    Energy Technology Data Exchange (ETDEWEB)

    Libersky, Matthew Murray [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-09-04

    The beta decay lifetime of the free neutron is an important input to the Standard Model of particle physics, but values measured using different methods have exhibited substantial disagreement. The UCN r experiment in development at Los Alamos National Laboratory (LANL) plans to explore better methods of measuring the neutron lifetime using ultracold neutrons (UCNs). In this experiment, UCNs are confined in a magneto-gravitational trap formed by a curved, asymmetric Halbach array placed inside a vacuum vessel and surrounded by holding field coils. If any defects present in the Halbach array are sufficient to reduce the local field near the surface below that needed to repel the desired energy level UCNs, loss by material interaction can occur at a rate similar to the loss by beta decay. A map of the magnetic field near the surface of the array is necessary to identify any such defects, but the array's curved geometry and placement in a vacuum vessel make conventional field mapping methods difficult. A system consisting of computer vision-based tracking and a rover holding a Hall probe has been designed to map the field near the surface of the array, and construction of an initial prototype has begun at LANL. The design of the system and initial results will be described here.

  5. Optical cooling and trapping highly magnetic atoms: The benefits of a spontaneous spin polarization

    CERN Document Server

    Dreon, Davide; Bouazza, Chayma; Maineult, Wilfried; Dalibard, Jean; Nascimbene, Sylvain

    2016-01-01

    From the study of long-range-interacting systems to the simulation of gauge fields, open-shell Lanthanide atoms with their large magnetic moment and narrow optical transitions open novel directions in the field of ultracold quantum gases. As for other atomic species, the magneto-optical trap (MOT) is the working horse of experiments but its operation is challenging, due to the large electronic spin of the atoms. Here we present an experimental study of narrow-line Dysprosium MOTs. We show that the combination of radiation pressure and gravitational forces leads to a spontaneous polarization of the electronic spin. The spin composition is measured using a Stern-Gerlach separation of spin levels, revealing that the gas becomes almost fully spin-polarized for large laser frequency detunings. In this regime, we reach the optimal operation of the MOT, with samples of typically $3\\times 10^8$ atoms at a temperature of 20$\\,\\mu$K. The spin polarization reduces the complexity of the radiative cooling description, whi...

  6. Green synthetic, multifunctional hybrid micelles with shell embedded magnetic nanoparticles for theranostic applications.

    Science.gov (United States)

    Li, Yongyong; Ma, Junping; Zhu, Haiyan; Gao, Xiaolong; Dong, Haiqing; Shi, Donglu

    2013-08-14

    The objective of this study is to design and develop a green-synthetic, multifunctional hybrid micelles with shell embedded magnetic nanoparticles for theranostic applications. The hybrid micelles were engineered based on complex micelles self-assembled from amphiphilic block copolymers Pluronic F127 and peptide-amphiphile (PA) pal-AAAAHHHD. The reason to choose PA is due to its amphiphilic character and the coordination capability for Fe(3+) and Fe(2+). The PA incorporation allows the in situ growth of the magnetic iron oxide nanoparticles onto the complex micelles, to yield the nanostructures with shell embedded magnetic nanoparticles at an ambient condition without any organic solvents. The anticancer drug doxorubicin (DOX) can be efficiently loaded into the hybrid micelles. Interestingly, the magnetic nanoparticles anchored on the shell were found to significantly retard the DOX release behavior of the drug loaded hybrid micelles. It was proposed that a cross-linking effect of the shell by magnetic nanoparticles is a key to underlie the above intriguing phenomenon, which could enhance the stability and control the drug diffusion of the hybrid micelles. Importantly, in vitro and in vivo magnetic resonance imaging (MRI) revealed the potential of these hybrid micelles to be served as a T2-weighted MR imaging contrast enhancer for clinical diagnosis.

  7. Electron Trapping in Multipole Magnet%多极场的电子云俘获效应研究

    Institute of Scientific and Technical Information of China (English)

    朱雄伟; 国智元

    2004-01-01

    The electron cloud effect limits the performance of several accelerators with high beam current, such as SLAC and KEK Bfactories, the CERN SPS and the CERN PS. In this paper, the electron trapping in general 2n multipole magnet ( n is integer) isstudied, and we find that there exists electron trapping in the adiabatic region of the multiple magnet ( n>1 ).%电子云效应限制了几台加速器的高束流密度运行,例如SLAC和KEK的B工厂,CERN的SPS与PS.本文运用辛流形上的1-form李摄动法研究了2n多极场的电子云俘获效应,结果发现在多极磁铁(n>1)的绝热区存在电子俘获.

  8. Dissipative dust-acoustic shock waves in a varying charge electronegative magnetized dusty plasma with trapped electrons

    Energy Technology Data Exchange (ETDEWEB)

    Bacha, Mustapha [Faculty of Physics, Theoretical Physics Laboratory, Plasma Physics Group, University of Bab-Ezzouar, USTHB, B.P. 32, El Alia, Algiers 16111 (Algeria); Tribeche, Mouloud, E-mail: mouloudtribeche@yahoo.fr, E-mail: mtribeche@usthb.dz [Faculty of Physics, Theoretical Physics Laboratory, Plasma Physics Group, University of Bab-Ezzouar, USTHB, B.P. 32, El Alia, Algiers 16111 (Algeria); Algerian Academy of Sciences and Technologies, Algiers (Algeria)

    2016-08-15

    The combined effects of an oblique magnetic field and electron trapping on dissipative dust-acoustic waves are examined in varying charge electronegative dusty plasmas with application to the Halley Comet plasma (∼10{sup 4} km from the nucleus). A weakly nonlinear analysis is carried out to derive a modified Korteweg-de Vries-Burger-like equation. Making use of the equilibrium current balance equation, the physically admissible values of the electron trapping parameter are first constrained. We then show that the Burger dissipative term is solely due to the dust charge variation process. It is found that an increase of the magnetic field obliqueness or a decrease of its magnitude renders the shock structure more dispersive.

  9. Shape-controlled fabrication of magnetite silver hybrid nanoparticles with high performance magnetic hyperthermia.

    Science.gov (United States)

    Ding, Qi; Liu, Dongfang; Guo, Dawei; Yang, Fang; Pang, Xingyun; Che, Renchao; Zhou, Naizhen; Xie, Jun; Sun, Jianfei; Huang, Zhihai; Gu, Ning

    2017-04-01

    Superparamagnetic Fe3O4 nanoparticles (NPs)-based hyperthermia is a promising non-invasive approach for cancer therapy. However, the heat transfer efficiency of Fe3O4 NPs is relative low, which hinders their practical clinical applications. Therefore, it is promising to improve the magnetic hyperthermia efficiency by exploring the higher performance magnetic NPs-based hybrid nanostructures. In the current study, it presents a straightforward in situ reduction method for the shape-controlled preparation of magnetite (Fe3O4) silver (Ag) hybrid NPs designed as magnetic hyperthermia heat mediators. The magnetite silver hybrid NPs with core-shell (Fe3O4@Ag) or heteromer (Fe3O4-Ag) structures exhibited a higher biocompatibility with SMMC-7721 cells and L02 cells than the individual Ag NPs. Importantly, in the magnetic hyperthermia, with the exposure to alternating current magnetic field, the Fe3O4@Ag and Fe3O4-Ag hybrid NPs indicated much better tumor suppression effect against SMMC-7721 cells than the individual Fe3O4 NPs in vitro and in vivo. These results demonstrate that the hybridisation of Fe3O4 and Ag NPs could greatly enhance the magnetic hyperthermia efficiency of Fe3O4 NPs. Therefore, the Fe3O4@Ag and Fe3O4-Ag hybrid NPs can be used to be as high performance magnetic hyperthermia mediators based on a simple and effective preparation approach.

  10. Effect of the repulsive force in the HTSC-permanent magnet hybrid bearing system

    Energy Technology Data Exchange (ETDEWEB)

    Ohashi, S., E-mail: ohashi@ipcku.kansai-u.ac.j [Kansai University, 3-3-35, Yamate-cho, Suita, Osaka 564-8680 (Japan); Kobayashi, S. [Kansai University, 3-3-35, Yamate-cho, Suita, Osaka 564-8680 (Japan)

    2009-10-15

    Magnetic levitation using the pinning force of the YBaCuO high-T{sub c} bulk superconductor (HTSC) materials has an advantage to achieve stable levitation without control. To increase levitation force, the HTSC-permanent magnet hybrid magnetic bearing system is introduced. A circular shaped three phase Nd-Fe-B permanent magnet is installed on the rotor, and HTSC bulk superconductor is set on the stator. The additional permanent magnet is installed under the HTSC. Repulsive force of the permanent magnet is used for levitation, and pinning force between the HTSC and permanent magnet is used for guidance force of the bearing. In this system, relationship between permanent magnet and the HTSC is important. When repulsive force of the permanent magnet is large, pinning force of superconductor is used to keep the rotor position. As a result, stability for the lateral direction is decreased with hybrid system. For levitation force, effect of the hybrid system is not observed with column HTSC. Compared with the ring HTSC results, the following thing is considered. Because there is no space that flux of one permanent magnet acts on the other one with the column HTSC configuration, interaction between two permanent magnets becomes small.

  11. Effect of the repulsive force in the HTSC-permanent magnet hybrid bearing system

    Science.gov (United States)

    Ohashi, S.; Kobayashi, S.

    2009-10-01

    Magnetic levitation using the pinning force of the YBaCuO high- Tc bulk superconductor (HTSC) materials has an advantage to achieve stable levitation without control. To increase levitation force, the HTSC-permanent magnet hybrid magnetic bearing system is introduced. A circular shaped three phase Nd-Fe-B permanent magnet is installed on the rotor, and HTSC bulk superconductor is set on the stator. The additional permanent magnet is installed under the HTSC. Repulsive force of the permanent magnet is used for levitation, and pinning force between the HTSC and permanent magnet is used for guidance force of the bearing. In this system, relationship between permanent magnet and the HTSC is important. When repulsive force of the permanent magnet is large, pinning force of superconductor is used to keep the rotor position. As a result, stability for the lateral direction is decreased with hybrid system. For levitation force, effect of the hybrid system is not observed with column HTSC. Compared with the ring HTSC results, the following thing is considered. Because there is no space that flux of one permanent magnet acts on the other one with the column HTSC configuration, interaction between two permanent magnets becomes small.

  12. Quantitation of isobaric phosphatidylcholine species in human plasma using a hybrid quadrupole linear ion-trap mass spectrometer.

    Science.gov (United States)

    Zacek, Petr; Bukowski, Michael; Rosenberger, Thad A; Picklo, Matthew

    2016-12-01

    Phosphatidylcholine (PC) species in human plasma are used as biomarkers of disease. PC biomarkers are often limited by the inability to separate isobaric PCs. In this work, we developed a targeted shotgun approach for analysis of isobaric and isomeric PCs. This approach is comprised of two MS methods: a precursor ion scanning (PIS) of mass m/z 184 in positive mode (PIS m/z +184) and MS(3) fragmentation in negative mode, both performed on the same instrument, a hybrid triple quadrupole ion-trap mass spectrometer. The MS(3) experiment identified the FA composition and the relative abundance of isobaric and sn-1, sn-2 positional isomeric PC species, which were subsequently combined with absolute quantitative data obtained by PIS m/z +184 scan. This approach was applied to the analysis of a National Institute of Standards and Technology human blood plasma standard reference material (SRM 1950). We quantified more than 70 PCs and confirmed that a majority are present in isobaric and isomeric mixtures. The FA content determined by this method was comparable to that obtained using GC with flame ionization detection, supporting the quantitative nature of this MS method. This methodology will provide more in-depth biomarker information for clinical and mechanistic studies.

  13. Design of a cryocooler-cooled magnet for a compact hybrid magnet; Konpakuto haiburiddo magunetto yo reitoki reikyaku chodendo magunetto no gainen sekkei

    Energy Technology Data Exchange (ETDEWEB)

    Asano, T. [National Research Inst. for Metals, Tokyo (Japan); Koyanagi, K.; Matsumoto, S.; Kiyoshi, T.; Wada, H. [National Research Inst. for Metals, Tokyo (Japan); Japan Science and Technology Corpration, Saitama (Japan)

    1999-11-10

    In Natl. Res. Inst. for Metals, we examine the possibility of the operation of the hybrid magnet which combined refrigerating machine conduction cooling style superconducting magnet of the large diameter with the water-cooling copper magnet. The examination of the stability considering the electromagnetic interaction with the water-cooling copper magnet is required so that the conduction-cooling magnet may be made to run as a superconducting magnet for the hybrid magnet. In this report, the result of making on the magnet considering thermal load and coil protection to refrigerating machine conceptual design is described. (NEDO)

  14. Electromagnetic Forces in a Hybrid Magnetic-Bearing Switched-Reluctance Motor

    Science.gov (United States)

    Morrison, Carlos R.; Siebert, Mark W.; Ho, Eric J.

    2008-01-01

    Analysis and experimental measurement of the electromagnetic force loads on the hybrid rotor in a novel hybrid magnetic-bearing switched-reluctance motor (MBSRM) have been performed. A MBSRM has the combined characteristics of a switched-reluctance motor and a magnetic bearing. The MBSRM discussed in this report has an eight-pole stator and a six-pole hybrid rotor, which is composed of circular and scalloped lamination segments. The hybrid rotor is levitated using only one set of four stator poles, while a second set of four stator poles imparts torque to the scalloped portion of the rotor, which is driven in a traditional switched reluctance manner by a processor. Static torque and radial force analysis were done for rotor poles that were oriented to achieve maximum and minimum radial force loads on the rotor. The objective is to assess whether simple one-dimensional magnetic circuit analysis is sufficient for preliminary evaluation of this machine, which may exhibit strong three-dimensional electromagnetic field behavior. Two magnetic circuit geometries, approximating the complex topology of the magnetic fields in and around the hybrid rotor, were employed in formulating the electromagnetic radial force equations. Reasonable agreement between the experimental and the theoretical radial force loads predictions was obtained with typical magnetic bearing derating factors applied to the predictions.

  15. Magnetic-field-mediated coupling and control in hybrid atomic-nanomechanical systems

    CERN Document Server

    Tretiakov, A

    2016-01-01

    Magnetically coupled hybrid quantum systems enable robust quantum state control through Landau-Zener transitions. Here, we show that an ultracold atomic sample coupled to a nanomechanical resonator via oscillating magnetic fields can be used to cool the resonator's mechanical motion, to measure the mechanical temperature, and to enable entanglement of these mesoscopic objects. We calculate the expected coupling for both permanent-magnet and current-conducting nanostring resonators and describe how this hybridization is attainable using recently developed fabrication techniques, including SiN nanostrings and atom chips.

  16. Hybrid R-Fe-B/R-Co Magnets with Improved Thermal Stability

    Science.gov (United States)

    2009-12-23

    known that Nd2Fe14B -based magnets display excellent room temperature magnetic performance with (BH)max up to 50 MGOe. However, their low Curie... Nd2Fe14B - and Sm2Co17-based permanent magnets. This temperature range covers the exact temperatures that are very critical for many important...make a hybrid Nd2Fe14B /Sm2(Co,Fe,Cu,Zr)17 magnet that may combine the high magnetic performance of Nd2Fe14B and excellent high temperature stability

  17. Destabilization of beta-induce Alfvén eigenmodes by energetic trapped ions in low-magnetic-shear plasma

    Science.gov (United States)

    Ma, Ruirui; Chen, Wei; He, Hongda; Yu, Liming; Ding, Xuantong

    2017-10-01

    The dispersion relation for high toroidal mode number n beta-induced Alfvén eigenmodes (BAEs) excited by magnetically trapped energetic ions generated with ion-cyclotron resonance heating via precessional resonance in low magnetic shear (s) tokamak plasma is investigated analytically and numerically. The dynamics of the energetic particles (EPs) is treated non-perturbatively and finite drift orbit width (FOW) effects are taken into account. It is found that, depending on the plasma parameters, the most unstable mode can be either the BAE mode or the energetic particle mode (EPM). Both modes can resonate with the trapped-particles' magnetic precessional drifts and become unstable. The mode frequencies and growth rates depend strongly on the EP parameters. FOW can stabilize high-n BAE modes by reducing the wave-particle interaction. Magnetic shear has an important effect on the growth rate of the modes. For BAE, the growth rate presents the trend of first increase and following decrease with the increase of s. The peak positions of the mode growth rate move towards small s with increasing EPs' density. Besides, the BAE growth rate increases with n for small kϑρLE , and decreases for kϑρLE>0.34 . On the other hand, the EPM becomes stable for sufficiently large s and enters into the second stability regime.

  18. Two-dimensional magnetic modeling of ferromagnetic materials by using a neural networks based hybrid approach

    Energy Technology Data Exchange (ETDEWEB)

    Cardelli, E.; Faba, A. [Department of Engineering, University of Perugia, Via G. Duranti 93, 06125 Perugia (Italy); Laudani, A.; Lozito, G.M.; Riganti Fulginei, F.; Salvini, A. [Department of Engineering, Roma Tre University, Via V. Volterra 62, 00146 Rome (Italy)

    2016-04-01

    This paper presents a hybrid neural network approach to model magnetic hysteresis at macro-magnetic scale. That approach aims to be coupled together with numerical treatments of magnetic hysteresis such as FEM numerical solvers of the Maxwell's equations in time domain, as in case of the non-linear dynamic analysis of electrical machines, and other similar devices, allowing a complete computer simulation with acceptable run times. The proposed Hybrid Neural System consists of four inputs representing the magnetic induction and magnetic field components at each time step and it is trained by 2D and scalar measurements performed on the magnetic material to be modeled. The magnetic induction B is assumed as entry point and the output of the Hybrid Neural System returns the predicted value of the field H at the same time step. Within the Hybrid Neural System, a suitably trained neural network is used for predicting the hysteretic behavior of the material to be modeled. Validations with experimental tests and simulations for symmetric, non-symmetric and minor loops are presented.

  19. Magnetic trapping of silver and copper, and anomolous spin relaxation in the Ag-He system

    CERN Document Server

    Brahms, N; Johnson, C; Greytak, T; Kleppner, D; Doyle, J

    2008-01-01

    We have trapped large numbers of copper (Cu) and silver (Ag) atoms using buffer gas cooling. Up to 3 trillion Cu atoms and 40 trillion Ag atoms are trapped. Lifetimes are as long as 5 s, limited by collisions with the buffer gas. Ratios of elastic to inelastic collision rates with He are > 10^6, suggesting Cu and Ag are favorable for use in ultracold applications. The temperature dependence of the Ag-3He collision rate displays anomolous behavior, varying as T^(5.8). Lifetimes of laser ablated gold (Au) in 3He buffer gas are too short to permit trapping.

  20. A modified Rogowski coil for measurements of hybrid permanent magnets

    Energy Technology Data Exchange (ETDEWEB)

    Bertsche, K.

    1996-08-01

    For large permanent magnets, as proposed for the Fermilab Recycler Ring, it may be important to quickly verify that the magnet`s strength is correct. This may be important, for example, if a magnet is suspected of having changed due to some sort of accident. The field strength of a pure dipole can be readily measured with a Hall probe, but for indexed dipoles and for quadrupoles a Hall probe will not give very accurate results without precise positioning. We have investigated a different approach, the use of a modified Rogowski coil to measure the magnetic potential of each pole. As long as magnet geometry is fixed and known, measurement of the magnetic potential at each pole gives a good measurement of field strength even for magnets with large quadrupole components. The construction and use of such a coil and the precision of measurements made with it will be discussed. 4 refs., 5 figs.

  1. Using NV centers to probe magnetization dynamics in normal metal/magnetic insulator hybrid system at the nanoscale

    Science.gov (United States)

    Zhang, Huiliang; Ku, Mark J. H.; Han, Minyong; Casola, Francesco; van der Sar, Toeno; Yacoby, Amir; Walsworth, Ronald L.

    2016-05-01

    Understanding magnetization dynamics induced by electric current is of great interest for both fundamental and practical reasons. Great endeavor has been dedicated to spin-orbit torques (SOT) in metallic structures, while quantitative study of analogous phenomena in magnetic insulators remains challenging where transport measurements are not feasible. Recently we have developed techniques using nitrogen vacancy (NV) centers in diamond to probe few-nanometre-scale correlated-electron magnetic excitations (i.e., spin waves). Here we demonstrate how this powerful tool can be implemented to study magnetization dynamics inside ferromagnetic insulator, Yttrium iron garnet (YIG) with spin injection from electrical current through normal metal (Platinum in our case). Particularly our work will focus on NV magnetic detection, imaging, and spectroscopy of coherent auto-oscillations in Pt/YIG microdisc. Magnetic fluctuations and local temperature measurements, both with nearby NV centers, will also be interesting topics relevant to SOT physics in Pt/YIG hybrid system.

  2. On relation between mid-latitude ionospheric ionization and quasi-trapped energetic electrons during 15 December 2006 magnetic storm

    CERN Document Server

    Suvorova, A V; Dmitriev, A V

    2011-01-01

    We report simultaneous observations of intense fluxes of quasi-trapped energetic electrons and substantial enhancements of ionospheric electron concentration (EC) at low and middle latitudes over Pacific region during geomagnetic storm on 15 December 2006. Electrons with energy of tens of keV were measured at altitude of ~800 to 900 km by POES and DMSP satellites. Experimental data from COSMIC/FS3 satellites and global network of ground-based GPS receivers were used to determine height profiles of EC and vertical total EC, respectively. A good spatial and temporal correlation between the electron fluxes and EC enhancements was found. This fact allows us to suggest that the quasi-trapped energetic electrons can be an important source of ionospheric ionization at middle latitudes during magnetic storms.

  3. Rock magnetic and anisotropy of magnetic susceptibility(AMS) of earthquake affected soft sediments: Examples from Shillong and Latur (Deccan Trap), India.

    Science.gov (United States)

    Lakshmi, B. V., ,, Dr.; Gawali, Mr. Praveen B.; Deenadayalan, K., ,, Dr.; Ramesh, D. S., ,, Prof.

    2017-04-01

    Rock magnetic and anisotropy of magnetic susceptibility (AMS) of earthquake affected soft sediments: Examples from Shillong and Latur (Deccan Trap), India. B.V.Lakshmi, Praveen B.Gawali, K.Deenadayalan and D.S.Ramesh Indian Institute of Geomagnetism, plot 5, sector 18, Near Kalamboli Highway, New Panvel(W), Navi Mumbai 410218 Combined rock magnetism and anisotropy of magnetic susceptibility (AMS) studies on earthquake induced soft and non-soft sediments from Shillong and Latur, India have thrown up interesting results. The morphology of hysteresis loops, the pattern of isothermal remanent magnetization (IRM) acquisition, and temperature dependence of susceptibility indicate that titano-magnetite/magnetite is the main magnetic carrier in these sediments. We also analyzed the anisotropy of magnetic susceptibility (AMS) of liquefaction features within the seismically active Dauki fault, Shillong Plateau. We discovered that host sediments (non-liquefied), are characterized by an oblate AMS ellipsoid and liquefied sediment are characterized by a triaxial AMS ellipsoid, well grouped maximum susceptibility axis K1 (NNW-SSE trend). Field evidence and AMS analysis indicate that most of these features were emplaced by injection inferred to be due to seismically triggered fluidization. Anisotropy of magnetic susceptibility (AMS) of deformed and undeformed unconsolidated clay samples of Deccan Trap terrain from the 2000-year-old paleoearthquake site of Ther village, Maharashtra, India, was also studied. Such deposits are rare in the compact basaltic terrain because of which the results acquired are very important. The undeformed clay samples exhibit typical sedimentary fabric with an oblate AMS ellipsoid, whereas the deformed samples are tightly grouped in the inferred compression direction, probably effected by an earthquake, exhibiting prolate as well as oblate AMS ellipsoids. Rock magnetic and AMS methodology can help understand the behavior of different sediments to the

  4. Nonvolatile, reversible electric-field controlled switching of remanent magnetization in multifunctional ferromagnetic/ferroelectric hybrids

    Science.gov (United States)

    Brandlmaier, A.; Geprägs, S.; Woltersdorf, G.; Gross, R.; Goennenwein, S. T. B.

    2011-08-01

    In spin-mechanics, the magnetoelastic coupling in ferromagnetic/ferroelectric hybrid devices is exploited in order to realize an electric-voltage control of magnetization orientation. To this end, different voltage-induced elastic strain states are used to generate different magnetization orientations. In our approach, we take advantage of the hysteretic expansion and contraction of a commercial piezoelectric actuator as a function of electrical voltage to deterministically select one of two electro-remanent elastic strain states. We investigate the resulting magnetic response in a nickel thin film/piezoelectric actuator hybrid device at room temperature, using simultaneous magneto-optical Kerr effect and magnetotransport measurements. The magnetic properties of the hybrid can be consistently described in a macrospin model, i.e., in terms of a single magnetic domain. At zero external magnetic field, the magnetization orientation in the two electro-remanent strain states differs by 15°, which corresponds to a magnetoresistance change of 0.5%. These results demonstrate that the spin-mechanics scheme indeed enables a nonvolatile electrically read- and writable memory bit where the information is encoded in a magnetic property.

  5. Numerical investigation of magnetic sensor for DNA hybridization detection using planar transformer

    Directory of Open Access Journals (Sweden)

    Sayyed M. Azimi

    2007-12-01

    Full Text Available This paper introduces a sensor for detection of DNA hybridization and investigates its performance by means of computer simulation. A planar transformer with spiral windings is proposed for hybridization detection. In order to detect the occurrence of hybridization, single strand target DNA’s are tagged with magnetic beads. Target DNA’s are then exposed to known single strand probe DNA’s which are immobilized on the surface of a functionalized layer in the proximity of the sensor. The primary winding of the transformer is driven by an AC current source. The voltage at the secondary winding is used for detection. Once the hybridization is occurred, a layer of magnetic material is formed and the coupling between the windings is varied. These variations are reflected into the detecting output voltage. The magnitude of the output voltage is numerically calculated in terms of geometrical and physical parameters and the parameter values resulting in maximum response are derived.

  6. A Magnetic Flux Leakage and Magnetostrictive Guided Wave Hybrid Transducer for Detecting Bridge Cables

    Directory of Open Access Journals (Sweden)

    Jiang Xu

    2012-01-01

    Full Text Available Condition assessment of cables has gained considerable attention for the bridge safety. A magnetic flux leakage and magnetostrictive guided wave hybrid transducer is provided to inspect bridge cables. The similarities and differences between the two methods are investigated. The hybrid transducer for bridge cables consists of an aluminum framework, climbing modules, embedded magnetizers and a ribbon coil. The static axial magnetic field provided by the magnetizers meets the needs of the magnetic flux leakage testing and the magnetostrictive guided wave testing. The magnetizers also provide the attraction for the climbing modules. In the magnetic flux leakage testing for the free length of cable, the coil induces the axial leakage magnetic field. In the magnetostrictive guided wave testing for the anchorage zone, the coil provides a pulse high power variational magnetic field for generating guided waves; the coil induces the magnetic field variation for receiving guided waves. The experimental results show that the transducer with the corresponding inspection system could be applied to detect the broken wires in the free length and in the anchorage zone of bridge cables.

  7. Study on control method of running velocity for the permanent magnet-HTSC hybrid magnetically levitated conveyance system

    Energy Technology Data Exchange (ETDEWEB)

    Nishio, R.; Ikeda, M.; Sasaki, R. [Kansai University, 3-3-35 Yamate-cho, Suita, Osaka 564-8680 (Japan); Ohashi, S., E-mail: ohashi@kansai-u.ac.jp [Kansai University, 3-3-35 Yamate-cho, Suita, Osaka 564-8680 (Japan)

    2011-11-15

    The hybrid magnetically levitated carrying system is developed. Control method of running velocity of the carrier is studied. Running velocity is controlled by current of the propulsion coils. Propulsion characteristcs are improved. We have developed the magnetically levitated carrying system. In this system, pinning force of high temperature bulk super conductor (HTSC) is used for the levitation and guidance. Four HTSCs are installed on the carrier. The magnetic rail is set on the ground, and flux from the magnetic rail is pinned by HTSCs. To increase levitation force, repulsive force of the permanent magnet is used. The hybrid levitation system is composed. The permanent magnet is installed under the load stage of the carrier. Repulsive force by the permanent magnet between the load stage on the carrier and the magnetic rail on the ground is used to support the load weight. Levitation and guidance one by pinning effect of the YBaCuO HTSC in the carrier is used to levitate the carrier body. The load stage is separated from the carrier flame and can move freely for vertical direction levitation. For the propulsion system, electromagnet is installed on the surface of the magnetic rail. In this paper, control method of running velocity of the carrier is studied. Propulsion force is given as follows; Air core copper coils are installed on the magnetic rail. Interaction between current of these coils and permanent magnets on the carrier generates propulsion force. Running velocity is controlled by current of the propulsion coils. It is also changed by position of the carrier and the load weight. From the results, stability of the propulsion system is given, and propulsion characteristics are improved.

  8. Hybrid nanomaterials: anchoring magnetic molecules on naked gold nanocrystals.

    Science.gov (United States)

    Holmberg, Rebecca J; Hutchings, Amy-Jayne; Habib, Fatemah; Korobkov, Ilia; Scaiano, Juan C; Murugesu, Muralee

    2013-12-16

    The pairing of molecular magnets and nanomaterials couples top-down and bottom-up approaches to nanotechnology; facilitating a unique methodology to the controlled study of interfacial magnetic properties. Attaching Single-Molecule Magnets (SMMs) to "naked" gold nanoparticles is a novel method of exploring various avenues of magnetic nanotechnology, such as drug delivery, information storage, catalysis, and assembly of magnetic-nanostructural motifs. Herein we report the successful capping of laser ablation synthesized "naked" gold nanoparticles with a dinuclear dysprosium complex, while introducing new information regarding the changes in molecular magnetic properties upon surface attachment. We anticipate that this methodology in producing these magneto-plasmonic nanostructures not only provides answers to fundamental questions but also has the potential to provide new avenues to applications including information storage, multimodal imaging, biomedicine, and optoelectronics.

  9. Adsorption mechanism of magnetically separable Fe{sub 3}O{sub 4}/graphene oxide hybrids

    Energy Technology Data Exchange (ETDEWEB)

    Ouyang, Ke [Department of Chemical and Environment Engineering, Wuyi University, Jiangmen, Guangdong 529020 (China); Zhu, Chuanhe [Department of Civil, Construction and Environmental Engineering, Department of Chemical and Biological Engineering, Iowa State University, Ames, IA 50011 (United States); Zhao, Ya; Wang, Leichao [Department of Chemical and Environment Engineering, Wuyi University, Jiangmen, Guangdong 529020 (China); Xie, Shan, E-mail: wyuchemxs@126.com [Department of Chemical and Environment Engineering, Wuyi University, Jiangmen, Guangdong 529020 (China); Wang, Qun, E-mail: qunwang@iastate.edu [Department of Civil, Construction and Environmental Engineering, Department of Chemical and Biological Engineering, Iowa State University, Ames, IA 50011 (United States)

    2015-11-15

    Graphical abstract: A recyclable Fe{sub 3}O{sub 4}/graphene oxide (GO) magnetic hybrid was successfully synthesized via a facile one-pot polylol approach and exhibited an effective adsorption of BPA in aqueous solution. - Highlights: • Magnetically separable Fe{sub 3}O{sub 4}/GO hybrids were synthesized via a facile one-pot polylol approach. • The Fe{sub 3}O{sub 4}/GO hybrid could be easily recovered and met the need of magnetic separation, exhibiting excellent reproducibility and reusability. • The hybrids showed excellent adsorption ability for bisphenol A in aqueous solution. • The effect of pH value, temperature and coexisting ions on the adsorption was studied. • π–π interactions were postulated to be the primary mechanisms of adsorption of BPA on Fe{sub 3}O{sub 4}/GO hybrids. - Abstract: A reclaimable Fe{sub 3}O{sub 4}/graphene oxide (GO) magnetic hybrid was successfully synthesized via a facile one-pot polyol approach and employed as a recyclable adsorbent for Bisphenol A (BPA) in aqueous solutions. The maximum adsorption capacity (q{sub m}) of the Fe{sub 3}O{sub 4}/GO hybrid for BPA was 72.80 mg/g at 273 K. The kinetics of the adsorption process and the adsorption isotherm data were fitted using the Freundlich equation and a pseudo-second-order kinetic model. The results of the thermodynamic parameters ΔH°, ΔS° and ΔG° showed that the adsorption process was exothermic and spontaneous. Furthermore, the reusability of the samples was investigated, and the results indicated that the samples exhibited high stability. The magnetic characterization demonstrated that hybrids were superparamagnetic and could be recovered conveniently by magnetic separation. The strong π–π interaction was determined to be the predominant driving force behind the adsorption of BPA onto the Fe{sub 3}O{sub 4}/GO hybrid. Therefore, the Fe{sub 3}O{sub 4}/GO hybrid could be regarded as a potential adsorbent for wastewater treatment and purification processes.

  10. Synthesis of Ni-Au-ZnO ternary magnetic hybrid nanocrystals with enhanced photocatalytic activity.

    Science.gov (United States)

    Zeng, Deqian; Chen, Yuanzhi; Wang, Zhichao; Wang, Junbao; Xie, Qingshui; Peng, Dong-Liang

    2015-07-14

    The functional synergy between the metal and the semiconductor in metal-semiconductor hybrid nanocrystals with specific structures and morphologies makes them suitable candidates for a wide range of applications. To date, the synthesis and the corresponding properties of ternary metal-semiconductor hetero-nanostructures, especially for hybrid nanocrystals containing magnetic metals, are seldom discussed and thus worthy of extensive research. In this study, we report a nonaqueous approach for the synthesis of Ni-Au-ZnO ternary hybrid nanocrystals with three morphologies, including nanomultipods, matchstick-like nanorods and nanopyramids. In the synthetic strategy, the Ni precursor dissolved in oleylamine was injected into a hot solution containing preformed Au-ZnO nanocrystals with specific morphologies. Then Ni prefers to grow on the unoccupied surfaces of Au, thus forming a hybrid hetero-nanostructure which retains the main morphologies of Au-ZnO nanocrystals. The ultraviolet-visible spectra not only show the band gap absorption of ZnO but also exhibit a broadened and weakened surface plasmon resonance (SPR) band of Au. The Ni-Au-ZnO nanocrystals exhibit much higher photocatalytic efficiency than pure ZnO in the degradation of Rhodamine B. Meanwhile, these hybrid nanocrystals are superparamagnetic at room temperature and can be readily recycled by a magnetic field for reuse. The as-prepared ternary Ni-Au-ZnO hybrid nanocrystals possess plasmonic, magnetic and enhanced photocatalytic properties, and thus are expected to find wide applications in the future.

  11. Design and Analysis of the AlNiCo Hybrid Magnet in EMS Maglev Vehicles

    Directory of Open Access Journals (Sweden)

    Lv Chao

    2017-01-01

    Full Text Available In order to solve the problem of hybrid electromagnet lock orbit, we design a new type of AlNiCo-NdFeB hybrid levitation electromagnet. The theoretical analysis has be carried on and mathematical model is established for AlNiCo-NdFeB hybrid levitation electromagnet. Through two dimensional simulation, the electromagnetic characteristics of the suspended electromagnet are analyzed in the 3 typical operating conditions , which are in heavy load at gap 8mm, in full load at gap 16mm and in no-load at gap 3mm. And it’s compared with the traditional electromagnetic magnet and NdFeB hybrid electromagnet. Calculation and analysis show that the new hybrid levitation electromagnet can effectively solve the problems of the electromagnet lock orbit, at the same time, have a good dynamic performance and suspension regulation performance.

  12. Study on control method of running velocity for the permanent magnet-HTSC hybrid magnetically levitated conveyance system

    Science.gov (United States)

    Nishio, R.; Ikeda, M.; Sasaki, R.; Ohashi, S.

    2011-11-01

    We have developed the magnetically levitated carrying system. In this system, pinning force of high temperature bulk super conductor (HTSC) is used for the levitation and guidance. Four HTSCs are installed on the carrier. The magnetic rail is set on the ground, and flux from the magnetic rail is pinned by HTSCs. To increase levitation force, repulsive force of the permanent magnet is used. The hybrid levitation system is composed. The permanent magnet is installed under the load stage of the carrier. Repulsive force by the permanent magnet between the load stage on the carrier and the magnetic rail on the ground is used to support the load weight. Levitation and guidance one by pinning effect of the YBaCuO HTSC in the carrier is used to levitate the carrier body. The load stage is separated from the carrier flame and can move freely for vertical direction levitation. For the propulsion system, electromagnet is installed on the surface of the magnetic rail. In this paper, control method of running velocity of the carrier is studied. Propulsion force is given as follows; Air core copper coils are installed on the magnetic rail. Interaction between current of these coils and permanent magnets on the carrier generates propulsion force. Running velocity is controlled by current of the propulsion coils. It is also changed by position of the carrier and the load weight. From the results, stability of the propulsion system is given, and propulsion characteristics are improved.

  13. Design of magnetic akaganeite-cyanobacteria hybrid biofilms

    Energy Technology Data Exchange (ETDEWEB)

    Dahoumane, Si Amar [Universite Paris Diderot (Paris 7), CNRS, UMR 7086, Interfaces, Traitements, Organisation et Dynamique des Systemes (ITODYS), 15 rue Jean de Baif, F-75205 Paris Cedex 13 (France); Djediat, Chakib; Yepremian, Claude; Coute, Alain [Museum National d' Histoire Naturelle (MNHN), Departement RDDM, USM 505, 57 rue Cuvier, F-75005 Paris (France); Fievet, Fernand [Universite Paris Diderot (Paris 7), CNRS, UMR 7086, Interfaces, Traitements, Organisation et Dynamique des Systemes (ITODYS), 15 rue Jean de Baif, F-75205 Paris Cedex 13 (France); Brayner, Roberta, E-mail: roberta.brayner@univ-paris-diderot.f [Universite Paris Diderot (Paris 7), CNRS, UMR 7086, Interfaces, Traitements, Organisation et Dynamique des Systemes (ITODYS), 15 rue Jean de Baif, F-75205 Paris Cedex 13 (France)

    2010-07-30

    Common Anabaena cyanobacteria are shown to form intra-cellularly akaganeite {beta}-FeOOH nanorods of well-controlled size and unusual morphology at room temperature. High-resolution transmission electron microscopy showed that these nanorods present a complex arrangement of pores forming a spongelike structure. These hybrid akaganeite-cyanobacteria were used to form 'one-pot' hybrid biofilms. The hybrid biofilm presents higher coercivity (H{sub c} = 44.6 kA m{sup -1} (560 Oe)) when compared to lyophilized akaganeite-cyanobacteria powder (H{sub c} = 0.8 kA m{sup -1} (10 Oe)) due to the quasi-assembly of the cells on the glass substrate compared to the lyophilized randomly akaganeite-cyanobacteria powder.

  14. Development of an extraction type magnetometer under low temperature and high magnetic fields over 20 T by the hybrid magnet

    Energy Technology Data Exchange (ETDEWEB)

    Koyama, K; Sakakura, R; Watanabe, K [High Field Laboratory for Superconducting materials, Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan)], E-mail: kkoyama@imr.tohoku.ac.jp

    2009-03-01

    An extraction-type magnetometer has been developed, which is performed under the low temperature of 0.5-0.6 K using a {sup 3}He-refrigerator and high magnetic fields up to 18 T using a superconducting magnet (SM) and 27 T using a hybrid magnet (HM). Magnetization curves can be measured with the absolute value over 0.0005 emu using SM and 0.005 emu using HM. We confirmed that the resolution is 0.001 emu for SM and 0.005 emu for HM. For demonstrating the ability of the magnetometer, high field magnetization curves of NdO{sub 4}Ag in 0.6-4.2 K are presented.

  15. Magnetic trapping of silver and copper, and anomalous spin relaxation in the ag-he system.

    Science.gov (United States)

    Brahms, Nathan; Newman, Bonna; Johnson, Cort; Greytak, Tom; Kleppner, Daniel; Doyle, John

    2008-09-01

    We have trapped large numbers of copper (Cu) and silver (Ag) atoms using buffer-gas cooling. Up to 3 x 10{12} Cu atoms and 4 x 10{13} Ag atoms are trapped. Lifetimes are as long as 5 s, limited by collisions with the buffer gas. Ratios of elastic to inelastic collision rates with He are >or=10{6}, suggesting Cu and Ag are favorable for use in ultracold applications. The temperature dependence of the Ag-3He collision rate varies as T;{5.8+/-0.4}. We find that this temperature dependence is inconsistent with the behavior predicted for relaxation arising from the spin-rotation interaction, and conclude that the Ag-3He system displays anomalous collisional behavior in the multiple-partial wave regime. Gold (Au) was ablated into 3He buffer gas, however, atomic Au lifetimes were observed to be too short to permit trapping.

  16. Fabrication of Magnetic-Antimicrobial-Fluorescent Multifunctional Hybrid Microspheres and Their Properties

    Directory of Open Access Journals (Sweden)

    Ling-Han Xiao

    2013-04-01

    Full Text Available Novel magnetic-antimicrobial-fluorescent multifunctional hybrid microspheres with well-defined nanostructure were synthesized by the aid of a poly(glycidyl methacrylate (PGMA template. The hybrid microspheres were fully characterized by scanning electron microscopy (SEM, transmission electron microscopy (TEM, Fourier transform infrared (FTIR, X-ray diffraction (XRD and digital fluorescence microscope. The as-synthesized microspheres PGMA, amino-modified PGMA (NH2-PGMA and magnetic PGMA (M-PGMA have a spherical shape with a smooth surface and fine monodispersity. M-PGMA microspheres are super-paramagnetic, and their saturated magnetic field is 4.608 emu·g−1, which made M-PGMA efficiently separable from aqueous solution by an external magnetic field. After poly(haxemethylene guanidine hydrochloride (PHGH functionalization, the resultant microspheres exhibit excellent antibacterial performance against both Gram-positive and Gram-negative bacteria. The fluorescence feature originating from the quantum dot CdTe endowed the hybrid microspheres with biological functions, such as targeted localization and biological monitoring functions. Combination of magnetism, antibiosis and fluorescence into one single hybrid microsphere opens up the possibility of the extensive study of multifunctional materials and widens the potential applications.

  17. Comparison of Mosquito Magnet and Biogents Sentinel Traps for Operational Surveillance of Container-Inhabiting Aedes (Diptera: Culicidae) Species.

    Science.gov (United States)

    Rochlin, Ilia; Kawalkowski, Margaret; Ninivaggi, Dominick V

    2016-03-01

    Container-inhabiting Aedes are among the most medically important mosquito vectors of diseases. They also impact health and quality of life by their persistent and severe biting. Monitoring of container-inhabiting Aedes species is challenging due to the need for specialized traps and lures. Biogents Sentinel (BGS) trap has become a standard for Aedes albopictus (Skuse) surveillance; however, it has substantial problems with durability, quality of construction, and sample exposure to the elements. The goal of this study was to develop a methodology for collecting medically important container-inhabiting Aedes species in numbers sufficient for population trend analysis, control efficacy studies, and pathogen testing. Mosquito Magnets (MM) baited with BG lure and R-octenol were selected as the most practical alternative to BGS, collecting significantly more Ae. albopictus (32.1 ± 0.7 vs. 5.6 ± 0.1), Aedes japonicus (Theobald) (10.1 ± 0.4 vs. 1.2 ± 0.02), and Aedes triseriatus (Say) (0.9 ± 0.04 vs. 0.04 ± 0.004) females on average per trapping under a variety of weather conditions. MM can be particularly useful for long-term surveillance or when large numbers of specimens are required for pathogen isolation, such as at the sites with suspected dengue or chikungunya transmission.

  18. Neutron lifetime measurements and effective spectral cleaning with an ultracold neutron trap using a vertical Halbach octupole permanent magnet array

    CERN Document Server

    Leung, K K H; Ivanov, S; Rosenau, F; Zimmer, O

    2016-01-01

    Ultracold neutron (UCN) storage measurements were made in a trap constructed from a 1.3 T Halbach Octupole PErmanent (HOPE) magnet array aligned vertically, using the TES-port of the PF2 source at the Institut Laue-Langevin. A mechanical UCN valve at the bottom of the trap was used for filling and emptying. This valve was covered with Fomblin grease to induce non-specular reflections and was used in combination with a movable polyethylene UCN remover inserted from the top for cleaning of above-threshold UCNs. Loss due to UCN depolarization was suppressed with a minimum 2 mT bias field. Without using the UCN remover, a total storage time constant of $(712 \\pm 19)$ s was observed; with the remover inserted for 80 s and used at either 80 cm or 65 cm from the bottom of the trap, time constants of $(824 \\pm 32)$ s and $(835 \\pm 36)$ s were observed. Combining the latter two values, a neutron lifetime of $\\tau_{\\rm n} = (887 \\pm 39)$ s is extracted after primarily correcting for losses at the UCN valve. The time co...

  19. Exchange coupling in hybrid anisotropy magnetic multilayers quantified by vector magnetometry

    Energy Technology Data Exchange (ETDEWEB)

    Morrison, C., E-mail: C.Morrison.2@warwick.ac.uk; Miles, J. J.; Thomson, T. [School of Computer Science, University of Manchester, Manchester M13 9PL (United Kingdom); Anh Nguyen, T. N. [Materials Physics, School of ICT, KTH Royal Institute of Technology, Electrum 229, 164 40 Kista (Sweden); Spintronics Research Group, Laboratory for Nanotechnology (LNT), VNU-HCM, Ho Chi Minh City (Viet Nam); Fang, Y.; Dumas, R. K. [Department of Physics, University of Gothenburg, 412 96 Gothenburg (Sweden); Åkerman, J. [Materials Physics, School of ICT, KTH Royal Institute of Technology, Electrum 229, 164 40 Kista (Sweden); Department of Physics, University of Gothenburg, 412 96 Gothenburg (Sweden)

    2015-05-07

    Hybrid anisotropy thin film heterostructures, where layers with perpendicular and in-plane anisotropy are separated by a thin spacer, are novel materials for zero/low field spin torque oscillators and bit patterned media. Here, we report on magnetization reversal and exchange coupling in a archetypal Co/Pd (perpendicular)-NiFe (in-plane) hybrid anisotropy system studied using vector vibrating sample magnetometry. This technique allows us to quantify the magnetization reversal in each individual magnetic layer, and measure of the interlayer exchange as a function of non-magnetic spacer thickness. At large (>1 nm) spacer thicknesses Ruderman-Kittel-Kasuya-Yosida-like exchange dominates, with orange-peel coupling providing a significant contribution only for sub-nm spacer thickness.

  20. Hybrid bronchoscope tracking using a magnetic tracking sensor and image registration.

    Science.gov (United States)

    Mori, Kensaku; Deguchi, Daisuke; Akiyama, Kenta; Kitasaka, Takayuki; Maurer, Calvin R; Suenaga, Yasuhito; Takabatake, Hirotsugu; Mori, Masaki; Natori, Hiroshi

    2005-01-01

    In this paper, we propose a hybrid method for tracking a bronchoscope that uses a combination of magnetic sensor tracking and image registration. The position of a magnetic sensor placed in the working channel of the bronchoscope is provided by a magnetic tracking system. Because of respiratory motion, the magnetic sensor provides only the approximate position and orientation of the bronchoscope in the coordinate system of a CT image acquired before the examination. The sensor position and orientation is used as the starting point for an intensity-based registration between real bronchoscopic video images and virtual bronchoscopic images generated from the CT image. The output transformation of the image registration process is the position and orientation of the bronchoscope in the CT image. We tested the proposed method using a bronchial phantom model. Virtual breathing motion was generated to simulate respiratory motion. The proposed hybrid method successfully tracked the bronchoscope at a rate of approximately 1 Hz.

  1. Trapped antihydrogen

    Science.gov (United States)

    Butler, E.; Andresen, G. B.; Ashkezari, M. D.; Baquero-Ruiz, M.; Bertsche, W.; Bowe, P. D.; Cesar, C. L.; Chapman, S.; Charlton, M.; Deller, A.; Eriksson, S.; Fajans, J.; Friesen, T.; Fujiwara, M. C.; Gill, D. R.; Gutierrez, A.; Hangst, J. S.; Hardy, W. N.; Hayden, M. E.; Humphries, A. J.; Hydomako, R.; Jenkins, M. J.; Jonsell, S.; Jørgensen, L. V.; Kemp, S. L.; Kurchaninov, L.; Madsen, N.; Menary, S.; Nolan, P.; Olchanski, K.; Olin, A.; Povilus, A.; Pusa, P.; Rasmussen, C. Ø.; Robicheaux, F.; Sarid, E.; Seif el Nasr, S.; Silveira, D. M.; So, C.; Storey, J. W.; Thompson, R. I.; van der Werf, D. P.; Wurtele, J. S.; Yamazaki, Y.

    Precision spectroscopic comparison of hydrogen and antihydrogen holds the promise of a sensitive test of the Charge-Parity-Time theorem and matter-antimatter equivalence. The clearest path towards realising this goal is to hold a sample of antihydrogen in an atomic trap for interrogation by electromagnetic radiation. Achieving this poses a huge experimental challenge, as state-of-the-art magnetic-minimum atom traps have well depths of only ˜1 T (˜0.5 K for ground state antihydrogen atoms). The atoms annihilate on contact with matter and must be `born' inside the magnetic trap with low kinetic energies. At the ALPHA experiment, antihydrogen atoms are produced from antiprotons and positrons stored in the form of non-neutral plasmas, where the typical electrostatic potential energy per particle is on the order of electronvolts, more than 104 times the maximum trappable kinetic energy. In November 2010, ALPHA published the observation of 38 antiproton annihilations due to antihydrogen atoms that had been trapped for at least 172 ms and then released—the first instance of a purely antimatter atomic system confined for any length of time (Andresen et al., Nature 468:673, 2010). We present a description of the main components of the ALPHA traps and detectors that were key to realising this result. We discuss how the antihydrogen atoms were identified and how they were discriminated from the background processes. Since the results published in Andresen et al. (Nature 468:673, 2010), refinements in the antihydrogen production technique have allowed many more antihydrogen atoms to be trapped, and held for much longer times. We have identified antihydrogen atoms that have been trapped for at least 1,000 s in the apparatus (Andresen et al., Nature Physics 7:558, 2011). This is more than sufficient time to interrogate the atoms spectroscopically, as well as to ensure that they have relaxed to their ground state.

  2. Improvement of the levitation stability of the HTSC-permanent magnet hybrid bearing by using the new arrangement of the permanent magnet

    Science.gov (United States)

    Sukedaia, M.; Emoto, K.; Sugiyama, R.; Ohashi, S.

    The hybrid magnetic bearing using permanent magnets and the high temperature superconductor (HTSC) has been developed. Repulsive force of the permanent magnet is introduced to increase the load weight of the magnetic bearing. Effect of the hybrid system has been shown. Although the previous configuration improves the load weight of the rotor, levitation and guidance stability has been decreased because of the repulsive force of the permanent magnet. Three-dimensional numerical analysis of the system has been undertaken to reduce lateral force which decreases lateral stability of the rotor. From the results, effective arrangement of the hybrid system is given. Increment of the load weight is confirmed. Influence of the hybrid system on the pinning force between the HTSC and the permanent magnet is shown to be smaller than previous one.

  3. Survey of Trapped Plasmas at the Earth’s Magnetic Equator

    Science.gov (United States)

    1991-12-01

    not sampled for ions in this survey). This local time dependence appears to reflect the L versus local time dependance of the plasmapause. The regions...versus local time dependance of the plasmapause. The regions of peak occurrence probability for trapped ions were mutually exclusive with the high...4 Figure 2. Plasma D...sity L Dependance

  4. A Hybrid Nonlinear Control Scheme for Active Magnetic Bearings

    Science.gov (United States)

    Xia, F.; Albritton, N. G.; Hung, J. Y.; Nelms, R. M.

    1996-01-01

    A nonlinear control scheme for active magnetic bearings is presented in this work. Magnet winding currents are chosen as control inputs for the electromechanical dynamics, which are linearized using feedback linearization. Then, the desired magnet currents are enforced by sliding mode control design of the electromagnetic dynamics. The overall control scheme is described by a multiple loop block diagram; the approach also falls in the class of nonlinear controls that are collectively known as the 'integrator backstepping' method. Control system hardware and new switching power electronics for implementing the controller are described. Various experiments and simulation results are presented to demonstrate the concepts' potentials.

  5. Synchronous motor with hybrid permanent magnets on the rotor.

    Science.gov (United States)

    Slusarek, Barbara; Kapelski, Dariusz; Antal, Ludwik; Zalas, Pawel; Gwoździewicz, Maciej

    2014-07-10

    Powder metallurgy allows designers of electric motors to implement new magnetic circuit structures. A relatively new concept is the use of a magnet system consisting of various types of magnets on one rotor, for example sintered and bonded magnets. This concept has been applied to the design and manufacture of the four-pole rotor of a synchronous motor with 400 W power and a rotational speed of 1500 rpm. In this motor, the stator of an asynchronous motor type Sh 71-4B is applied. The application of the new construction of the rotor resulted in an increase in motor efficiency and power factor compared to an asynchronous motor with the same volume.

  6. Adsorption mechanism of magnetically separable Fe3O4/graphene oxide hybrids

    Science.gov (United States)

    Ouyang, Ke; Zhu, Chuanhe; Zhao, Ya; Wang, Leichao; Xie, Shan; Wang, Qun

    2015-11-01

    A reclaimable Fe3O4/graphene oxide (GO) magnetic hybrid was successfully synthesized via a facile one-pot polyol approach and employed as a recyclable adsorbent for Bisphenol A (BPA) in aqueous solutions. The maximum adsorption capacity (qm) of the Fe3O4/GO hybrid for BPA was 72.80 mg/g at 273 K. The kinetics of the adsorption process and the adsorption isotherm data were fitted using the Freundlich equation and a pseudo-second-order kinetic model. The results of the thermodynamic parameters ΔH°, ΔS° and ΔG° showed that the adsorption process was exothermic and spontaneous. Furthermore, the reusability of the samples was investigated, and the results indicated that the samples exhibited high stability. The magnetic characterization demonstrated that hybrids were superparamagnetic and could be recovered conveniently by magnetic separation. The strong π-π interaction was determined to be the predominant driving force behind the adsorption of BPA onto the Fe3O4/GO hybrid. Therefore, the Fe3O4/GO hybrid could be regarded as a potential adsorbent for wastewater treatment and purification processes.

  7. Hybrid Molecular and Spin Dynamics Simulations for Ensembles of Magnetic Nanoparticles for Magnetoresistive Systems.

    Science.gov (United States)

    Teich, Lisa; Schröder, Christian

    2015-11-13

    The development of magnetoresistive sensors based on magnetic nanoparticles which are immersed in conductive gel matrices requires detailed information about the corresponding magnetoresistive properties in order to obtain optimal sensor sensitivities. Here, crucial parameters are the particle concentration, the viscosity of the gel matrix and the particle structure. Experimentally, it is not possible to obtain detailed information about the magnetic microstructure, i.e., orientations of the magnetic moments of the particles that define the magnetoresistive properties, however, by using numerical simulations one can study the magnetic microstructure theoretically, although this requires performing classical spin dynamics and molecular dynamics simulations simultaneously. Here, we present such an approach which allows us to calculate the orientation and the trajectory of every single magnetic nanoparticle. This enables us to study not only the static magnetic microstructure, but also the dynamics of the structuring process in the gel matrix itself. With our hybrid approach, arbitrary sensor configurations can be investigated and their magnetoresistive properties can be optimized.

  8. Hybrid magnetic mechanism for active locomotion based on inchworm motion

    Science.gov (United States)

    Kim, Sung Hoon; Hashi, Shuichiro; Ishiyama, Kazushi

    2013-02-01

    Magnetic robots have been studied in the past. Insect-type micro-robots are used in various biomedical applications; researchers have developed inchworm micro-robots for endoscopic use. A biological inchworm has a looping locomotion gait. However, most inchworm micro-robots depend on a general bending, or bellows, motion. In this paper, we introduce a new robotic mechanism using magnetic force and torque control in a rotating magnetic field for a looping gait. The proposed robot is controlled by the magnetic torque, attractive force, and body mechanisms (two stoppers, flexible body, and different frictional legs). The magnetic torque generates a general bending motion. In addition, the attractive force and body mechanisms produce the robot’s looping motion within a rotating magnetic field and without the use of an algorithm for field control. We verified the device’s performance and analyzed the motion through simulations and various experiments. The robot mechanism can be applied to active locomotion for various medical robots, such as wireless endoscopes.

  9. Electronic and magnetic properties of modified silicene/graphene hybrid: Ab initio study

    Energy Technology Data Exchange (ETDEWEB)

    Chowdhury, Suman; Jana, Debnarayan, E-mail: cujanad@yahoo.com

    2016-11-01

    Among other two-dimensional (2D) novel materials, graphene and silicene both have drawn intense research interest among the researchers because they possess some unique intriguing properties which can change the scenario of the current electronic industry. In this work we have studied the electronic and the magnetic properties of a new kind of materials which is the hybrid of these two materials. Density functional theory (DFT) has been employed to calculate the relevant electronic and magnetic properties of this hybrid material. The pristine structure is modified by substitutional doping or by creating vacancy (Y-X, where one Y atom (Si or C) has been replaced by one X atom (B, N, Al, P or void)). The calculations have revealed that void systems are unstable while Si-B and Si-N are most stable ones. It has been noticed that some of these doped structures are magnetic in nature having induced mid-gap states in the system. In particular, Si-void structure is unstable yet it possess the highest magnetic moment of the order of 4 μ{sub B} (μ{sub B} being the Bohr magneton). The estimated band gaps of modified silicene/graphene hybrid from spin polarized partial density of states (PDOS) vary between 1.43–2.38 eV and 1.58–2.50 eV for spin-up and spin-down channel respectively. The implication of midgap states has been critically analysed in the light of magnetic nature. This study may be useful to build hybrid spintronic devices with controllable gap for spin up and spin down states. - Graphical abstract: We have studied the electronic and magnetic properties of silicene/graphene hybrid by employing density functional theory (DFT). - Highlights: • Electronic and magnetic properties of two dimensional graphene/silicene hybrid have been explored. • There is no magnetism in the system for a single carbon atom vacancy. • A net magnetic moment of 4.0 Bohr magneton is observed for a single silicon atom vacancy. • Unpaired electrons introduce mid-gap states which

  10. CURRENT VECTOR CONTROL OF PERMANENT-MAGNET SYNCHRONOUS MOTOR OF HYBRID VEHICLE ENGINE

    Directory of Open Access Journals (Sweden)

    S. Serikov

    2009-01-01

    Full Text Available Characteristics of traction permanent-magnet synchronous motor under current vector optimum control in the possible traction-speed mode area which are relevant for hybrid vehicle engine have been investigated. As a criterion of optimality a maximum of electromagnetic moment per unit of current have been taken.

  11. The solvothermal synthesis of magnetic iron oxide nanocrystals and the preparation of hybrid poly(L-lactide)-polyethyleneimine magnetic particles.

    Science.gov (United States)

    Stojanović, Zoran; Otoničar, Mojca; Lee, Jongwook; Stevanović, Magdalena M; Hwang, Mintai P; Lee, Kwan Hyi; Choi, Jonghoon; Uskoković, Dragan

    2013-09-01

    We report a simple and green procedure for the preparation of magnetic iron oxide nanocrystals via solvothermal synthesis. The nanocrystal synthesis was carried out under mild conditions in the water-ethanol-oleic acid solvent system with the use of the oleate anion as a surface modifier of nanocrystals and glucose as a reducing agent. Specific conditions for homogenous precipitation achieved in such a reaction system lead to the formation of uniform high-quality nanocrystals down to 5 nm in diameter. The obtained hydrophobic nanocrystals can easily be converted to hydrophilic magnetic nanoparticles by being immobilized in a poly(L-lactide)-polyethyleneimine polymeric matrix. These hybrid nano-constructs may find various biomedical applications, such as magnetic separation, gene transfection and/or magnetic resonance imaging. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Magnetic ripple and the modeling of lower-hybrid current drive in tokamaks

    Energy Technology Data Exchange (ETDEWEB)

    Peysson, Y.; Arslanbekov, R.; Basiuk, V.; Carrasco, J.; Litaudon, X.; Moreau, D. [Association Euratom-CEA, Centre d`Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Bizarro, J.P. [Instituto Superior Tecnico, Lisbon (Portugal). Lab. de Quimica Organica

    1996-01-01

    Using ray-tracing, a detailed investigation of the lower hybrid (LH) wave propagation in presence of toroidal magnetic field ripple is presented. By coupling ray tracing with a one-dimensional relativistic Fokker-Planck code, simulations of LH experiments have been performed for the Tore Supra tokamak. Taking into account magnetic ripple in LH simulations, a better agreement is found between numerical predictions and experimental observations, such as non-thermal Bremsstrahlung emission, current profile, ripple-induced power losses in local magnetic mirrors, when plasma conditions correspond to the ` `few passes` regime. (author). 47 refs.

  13. Fast modeling of flux trapping cascaded explosively driven magnetic flux compression generators.

    Science.gov (United States)

    Wang, Yuwei; Zhang, Jiande; Chen, Dongqun; Cao, Shengguang; Li, Da; Liu, Chebo

    2013-01-01

    To predict the performance of flux trapping cascaded flux compression generators, a calculation model based on an equivalent circuit is investigated. The system circuit is analyzed according to its operation characteristics in different steps. Flux conservation coefficients are added to the driving terms of circuit differential equations to account for intrinsic flux losses. To calculate the currents in the circuit by solving the circuit equations, a simple zero-dimensional model is used to calculate the time-varying inductance and dc resistance of the generator. Then a fast computer code is programmed based on this calculation model. As an example, a two-staged flux trapping generator is simulated by using this computer code. Good agreements are achieved by comparing the simulation results with the measurements. Furthermore, it is obvious that this fast calculation model can be easily applied to predict performances of other flux trapping cascaded flux compression generators with complex structures such as conical stator or conical armature sections and so on for design purpose.

  14. Study on Torque Calculation for Hybrid Magnetic Coupling and Influencing Factor Analysis

    Science.gov (United States)

    Wang, Shuang; Guo, Yong-cun; Wang, Peng-yu; Li, De-yong

    2017-03-01

    Specific to a problem that the present transmission of magnetic coupling torque was subjected to restrictions of its own structure, a hybrid magnetic coupling was proposed. Then, finite element method was adopted to carry out numerical calculations for its three-dimensional magnetic field to obtain three-dimensional magnetic field distribution of radial and axial configurations. Major influencing factors of its torque, such as lengths of axial and radial air gaps, thicknesses of axial and radial permanent magnets, the number of slots in axial copper rotor, thickness of axial and radial copper rotor, etc., were analyzed. The relevant results indicated that in certain conditions of shapes, ten magnetic poles of the axial permanent magnet rotor, nine of the radial permanent magnet rotor and nine slots from the axial copper rotor were used. Correspondingly, the axial copper rotor had a thickness of 20 mm and it was 5 mm for the radial copper rotor. Moreover, the maximum torque could reach 190 N.m approximately. If lengths of axial and radial air gaps increased, the torque may go down otherwise. Within a certain scope, the torque rose in the first place and then fell with increases in the permanent magnet thickness of axial permanent magnetic rotor, the number of axial and radial magnetic poles, the number of slots in axial copper rotor, and the thickness of axial copper rotor. Additionally, the number of slots in the axial copper rotor could not be equivalent to that of magnetic poles in axial permanent magnetic rotor. However, as the permanent magnet thickness of radial permanent magnetic rotor rose, the torque went up as well.

  15. Reduction hybrid artifacts of EMG-EOG in electroencephalography evoked by prefrontal transcranial magnetic stimulation

    Science.gov (United States)

    Bai, Yang; Wan, Xiaohong; Zeng, Ke; Ni, Yinmei; Qiu, Lirong; Li, Xiaoli

    2016-12-01

    Objective. When prefrontal-transcranial magnetic stimulation (p-TMS) performed, it may evoke hybrid artifact mixed with muscle activity and blink activity in EEG recordings. Reducing this kind of hybrid artifact challenges the traditional preprocessing methods. We aim to explore method for the p-TMS evoked hybrid artifact removal. Approach. We propose a novel method used as independent component analysis (ICA) post processing to reduce the p-TMS evoked hybrid artifact. Ensemble empirical mode decomposition (EEMD) was used to decompose signal into multi-components, then the components were separated with artifact reduced by blind source separation (BSS) method. Three standard BSS methods, ICA, independent vector analysis, and canonical correlation analysis (CCA) were tested. Main results. Synthetic results showed that EEMD-CCA outperformed others as ICA post processing step in hybrid artifacts reduction. Its superiority was clearer when signal to noise ratio (SNR) was lower. In application to real experiment, SNR can be significantly increased and the p-TMS evoked potential could be recovered from hybrid artifact contaminated signal. Our proposed method can effectively reduce the p-TMS evoked hybrid artifacts. Significance. Our proposed method may facilitate future prefrontal TMS-EEG researches.

  16. Initial position estimation strategy for a surface permanent magnet synchronous motor used in hybrid electric vehicles

    Institute of Scientific and Technical Information of China (English)

    Bing TIAN; Qun-tao AN; Li SUN‡; Dong-yang SUN; Jian-dong DUAN

    2016-01-01

    A novel nonlinear model for surface permanent magnet synchronous motors (SPMSMs) is adopted to estimate the initial rotor position for hybrid electric vehicles (HEVs). Usually, the accuracy of initial rotor position estimation for SPMSMs relies on magnetic saturation. To verify the saturation effect, the transient finite element analysis (FEA) model is presented first. Hybrid injection of a static voltage vector (SVV) superimposed with a high-frequency rotating voltage is proposed. The magnetic polarity is roughly identified with the aid of the saturation evaluation function, based on which an estimation of the position is performed. During this procedure, a special demodulation is suggested to extract signals of iron core saturation and rotor position. A Simulink/MATLAB platform for SPMSMs at standstill is constituted, and the effectiveness of the proposed strategy is verified. The proposed method is also validated by experimental results of an SPMSM drive.

  17. Design of smart oligo(ethylene glycol)-based biocompatible hybrid microgels loaded with magnetic nanoparticles.

    Science.gov (United States)

    Boularas, Mohamed; Gombart, Emilie; Tranchant, Jean-François; Billon, Laurent; Save, Maud

    2015-01-01

    This article reports a rational strategy for preparing smart oligo(ethylene glycol)-based hybrid microgels loaded with high content of homogeneously distributed preformed magnetic nanoparticles (NPs) (up to 33 wt%). The strategy is based on the synthesis of biocompatible multiresponsive microgels by precipitation copolymerization of di(ethylene glycol) methyl ether methacrylate, oligo(ethylene glycol) methyl ether methacrylate, methacrylic acid, and oligo(ethylene glycol)diac-rylate. An aqueous dispersion of preformed magnetic NPs is straightforwardly loaded into the microgels. Robust monodisperse thermoresponsive magnetic microgels are produced, exhibiting a constant value of the volume phase transition temperature whatever the NPs content. The homogeneous microstructure of the initial stimuli-responsive biocompatible microgels plays a crucial role for the design of unique well-defined ethylene glycol-based thermoresponsive hybrid microgels. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Facile method to synthesize magnetic iron oxides/TiO2 hybrid nanoparticles and their photodegradation application of methylene blue

    Directory of Open Access Journals (Sweden)

    Wu Wei

    2011-01-01

    Full Text Available Abstract Many methods have been reported to improving the photocatalytic efficiency of organic pollutant and their reliable applications. In this work, we propose a facile pathway to prepare three different types of magnetic iron oxides/TiO2 hybrid nanoparticles (NPs by seed-mediated method. The hybrid NPs are composed of spindle, hollow, and ultrafine iron oxide NPs as seeds and 3-aminopropyltriethyloxysilane as linker between the magnetic cores and TiO2 layers, respectively. The composite structure and the presence of the iron oxide and titania phase have been confirmed by transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectra. The hybrid NPs show good magnetic response, which can get together under an external applied magnetic field and hence they should become promising magnetic recovery catalysts (MRCs. Photocatalytic ability examination of the magnetic hybrid NPs was carried out in methylene blue (MB solutions illuminated under Hg light in a photochemical reactor. About 50% to 60% of MB was decomposed in 90 min in the presence of magnetic hybrid NPs. The synthesized magnetic hybrid NPs display high photocatalytic efficiency and will find recoverable potential applications in cleaning polluted water with the help of magnetic separation.

  19. Nanoscale switch for vortex polarization mediated by Bloch core formation in magnetic hybrid systems

    Science.gov (United States)

    Wohlhüter, Phillip; Bryan, Matthew Thomas; Warnicke, Peter; Gliga, Sebastian; Stevenson, Stephanie Elizabeth; Heldt, Georg; Saharan, Lalita; Suszka, Anna Kinga; Moutafis, Christoforos; Chopdekar, Rajesh Vilas; Raabe, Jörg; Thomson, Thomas; Hrkac, Gino; Heyderman, Laura Jane

    2015-08-01

    Vortices are fundamental magnetic topological structures characterized by a curling magnetization around a highly stable nanometric core. The control of the polarization of this core and its gyration is key to the utilization of vortices in technological applications. So far polarization control has been achieved in single-material structures using magnetic fields, spin-polarized currents or spin waves. Here we demonstrate local control of the vortex core orientation in hybrid structures where the vortex in an in-plane Permalloy film coexists with out-of-plane maze domains in a Co/Pd multilayer. The vortex core reverses its polarization on crossing a maze domain boundary. This reversal is mediated by a pair of magnetic singularities, known as Bloch points, and leads to the transient formation of a three-dimensional magnetization structure: a Bloch core. The interaction between vortex and domain wall thus acts as a nanoscale switch for the vortex core polarization.

  20. Hybrid materials: Magnetite-Polyethylenimine-Montmorillonite, as magnetic adsorbents for Cr(VI) water treatment.

    Science.gov (United States)

    Larraza, Iñigo; López-Gónzalez, Mar; Corrales, Teresa; Marcelo, Gema

    2012-11-01

    Hybrid materials formed by the combination of a sodium rich Montmorillonite (MMT), with magnetite nanoparticles (40 nm, Fe(3)O(4) NPs) coated with Polyethylenimine polymer (PEI 800 g/mol or PEI 25000 g/mol) were prepared. The intercalation of the magnetite nanoparticles coated with PEI among MMT platelets was achieved by cationic exchange. The resulting materials presented a high degree of exfoliation of the MMT sheets and a good dispersion of Fe(3)O(4) NPs on both the surface and among the layers of MMT. The presence of amine groups in the PEI structure not only aids the exfoliation of the MMT layers, but also gives to the hybrid material the necessary functionality to interact with heavy metals. These hybrid materials were used as magnetic sorbent for the removal of hexavalent chromium from water. The effect that pH, Cr(VI) concentration, and adsorbent material composition have on the Cr(VI) removal efficiency was studied. A complete characterization of the materials was performed. The hybrid materials showed a slight dependence of the removal efficiency with the pH in a wide range (1-9). A maximum amount of adsorption capacity of 8.8 mg/g was determined by the Langmuir isotherm. Results show that these hybrid materials can be considered as potential magnetic adsorbent for the Cr(VI) removal from water in a wide range of pH.

  1. Detailed Analysis Case Studies of Trapped Plasmas at the Earth’s Magnetic Equator

    Science.gov (United States)

    1993-06-01

    5 Figure 2. Plasma Density L Dependance ...... ......... 7 Figure 3. Plasmapause Magnetic Activity Dependance . . 8 Figure 4. Plasma Density L... Dependance - Normalized . . 10 Figure 5. The Dusk Bulge . . . .............. 13 Figure 6. Magnetosphere’s Electric and Magnetic Fields 14 Figure 7...1970). 6 -. ~ .ZJ.:AUGUST 12,1968 . -. ----- OUTBOUND PASS - 2 3 4 5 ___ ... 7....9 L Figure 2. Plasma Density L Dependance 7 0D3 #n /2 OUT JND tN

  2. Hybrid model predictive control for speed control of permanent magnet synchronous motor with saturation

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    A discrete-time hybrid model of a permanent magnet synchronous motor (PMSM) with saturation in voltage and current is formulated.The controller design with incorporated constraints is achieved in a systematic way from modeling to control synthesis and implementation.The Hybrid System Description Language is used to obtain a mixed-logical dynamical (MLD) model.Based on the MLD model,a model predictive controller is designed for an optimal speed regulation of the motor.For reducing computation complexity and ...

  3. Basic Characteristics and Design of a Novel Hybrid Magnetic Bearing for Wind Turbines

    Directory of Open Access Journals (Sweden)

    Yanjun Yu

    2016-11-01

    Full Text Available This paper proposes a five-degree-of-freedom (5-DOF hybrid magnetic bearing (HMB for direct-drive wind turbines, which can realize suspension in the 4-DOF radial and 1-DOF axial directions. Only two sets of radial control windings are employed in the proposed HMB because only one set of radial control windings can achieve the 2-DOF suspension in the radial direction. Unlike the traditional active thrust magnetic bearings, this paper uses a cylindrical rotor core without a large thrust disc in the novel HMB. The numbers of the controller, power amplifier and system volume can be reduced in the magnetic suspension system. This paper also presents the structure and basic characteristics of the proposed magnetic bearing. A precision equivalent magnetic circuit analysis of the permanent magnet ring and control magnetic field is conducted in this study, in consideration of the non-uniform distribution of magnetic density. Accordingly, the mathematical models, including the suspension force expression, are derived based on the accurate equivalent magnetic circuit. The basic principle of the structure parameter design is presented, based on the given key parameters. The accuracy of the analytical method is further validated by 3D finite element analysis.

  4. Measuring out-of-time-order correlations and multiple quantum spectra in a trapped ion quantum magnet

    CERN Document Server

    Gärttner, Martin; Safavi-Naini, Arghavan; Wall, Michael L; Bollinger, John J; Rey, Ana Maria

    2016-01-01

    Highly controllable arrays of ions and ultra-cold atoms are providing exciting opportunities for realizing quantum simulators of complex many-body phenomena that can provide insights into unsolved problems in modern science. A fundamental step towards this goal is the development of protocols that can quantify how a quantum simulator builds up quantum correlations and stores quantum information starting from easily prepared uncorrelated states. Out-of-time-order correlation functions have been recently suggested as ideal probes to accomplish this task, because they can quantify the spreading, or "scrambling", of quantum information and set speed limits for thermalization. They might also enable experimental tests of the holographic duality between quantum and gravitational systems. Here we report experimental measurements of dynamics of out-of-time-order correlations in a quantum simulator of more than 100 ions in a Penning trap by using the many-body echo sequence developed in the context of nuclear magnetic...

  5. Hot-injection synthesis of Ni-ZnO hybrid nanocrystals with tunable magnetic properties and enhanced photocatalytic activity

    Science.gov (United States)

    Zeng, Deqian; Qiu, Yulong; Chen, Yuanzhi; Zhang, Qinfu; Liu, Xiang; Peng, Dong-Liang

    2017-04-01

    Magnetic metal-semiconductor hybrid nanocrystals containing ferromagnetic Ni and semiconductor ZnO have been prepared via a hot-injection route. The Ni-ZnO hybrid nanocrystals have a flower-like morphology that consists of Ni inner cores and ZnO petal shells. In spite of their large lattice mismatch, ZnO nanocrystals can still grow on faceted Ni nanocrystals to form stable interfaces. The composition of Ni-ZnO hybrid nanocrystals is readily controlled, and the average size of Ni core is tunable from 25 to 50 nm. Room temperature ferromagnetic properties are observed in these hybrid nanocrystals, and tunable magnetic properties also can be achieved by varying the size of Ni core. The as-prepared Ni-ZnO hybrid nanocrystals exhibit enhanced photocatalytic performance under ultraviolet light illumination as compared to pure ZnO nanocrystals. Furthermore, the superior reusability of hybrid nanocrystals for photocatalytic application is achieved by virtue of their magnetic properties. The facile and efficient seed-mediate strategy is particularly attractive to construct hybrid magnetic-semiconducting heterostructures. The as-obtained Ni-ZnO hybrid nanocrystals offer great potential for various applications due to their combined magnetic and semiconducting properties and low-cost earth-abundant availability.

  6. Improvement of charged particles transport across a transverse magnetic filter field by electrostatic trapping of magnetized electrons

    Energy Technology Data Exchange (ETDEWEB)

    Das, B. K., E-mail: bdyt.ds@rediffmail.com; Hazarika, P.; Chakraborty, M. [Centre of Plasma Physics-Institute for Plasma Research, Tepesia-782402, Kamrup, Assam (India); Bandyopadhyay, M., E-mail: mainak@iter-india.org [ITER-India, Institute for Plasma Research, Gandhinagar-382025, Gujarat (India)

    2014-07-15

    A study on the transport of charged particles across a magnetic filter field has been carried out in a double plasma device (DPD) and presented in this manuscript. The DPD is virtually divided into two parts viz. source and target regions by a transverse magnetic field (TMF) which is constructed by inserting strontium ferrite magnets into two stainless steel rectangular tubes. Plasma electrons are magnetized but ions are unmagnetized inside the TMF region. Negative voltages are applied to the TMF tubes in order to reduce the loss of electrons towards them. Plasma is produced in the source region by filament discharge method and allowed to flow towards the target region through this negatively biased TMF. It is observed that in the target region, plasma density can be increased and electron temperature decreased with the help of negatively biased TMF. This observation is beneficial for negative ion source development. Plasma diffusion across the negatively biased TMF follows Bohm or anomalous diffusion process when negative bias voltage is very less. At higher negative bias, diffusion coefficient starts deviating from the Bohm diffusion value, associated with enhanced plasma flow in the target region.

  7. Optimum Design and Analysis of Axial Hybrid Magnetic Bearings Using Multi-Objective Genetic Algorithms

    Science.gov (United States)

    Rao, J. S.; Tiwari, R.

    2012-01-01

    Design optimization of axial hybrid magnetic thrust bearings (with bias magnets) was carried out using multi-objective evolutionary algorithms (MOEAs) and compared with the case of electromagnetic bearings (without bias magnets). Mathematical models of objective functions and associated constraints are presented and discussed. The different aspects of implemented MOEA are discussed. It is observed that the size of the bearing with bias magnets is considerably reduced as compared to the case of those without bias magnets, with the objective function as the minimization of weight for the same operating conditions. Similarly, current densities aret reduced drastically with biased magnets when the objective function is chosen as the minimization of the power loss. For illustration of various performances of the bearing, a typical design has been chosen from the final optimized population by an "a posteriori" approach. Sensitivities for both the objective functions with respect to the outer radius, the inner radius, and the height of coil are observed to be approximately in the ratio 2.5:1.6:1. Analysis of final optimized population has been carried out and is compared with the case without bias magnets and some salient points are observed in the case of using bias magnets.

  8. Polystyrene-Core-Silica-Shell Hybrid Particles Containing Gold and Magnetic Nanoparticles.

    Science.gov (United States)

    Tian, Jia; Vana, Philipp

    2016-02-18

    Polystyrene-core-silica-shell hybrid particles were synthesized by combining the self-assembly of nanoparticles and the polymer with a silica coating strategy. The core-shell hybrid particles are composed of gold-nanoparticle-decorated polystyrene (PS-AuNP) colloids as the core and silica particles as the shell. PS-AuNP colloids were generated by the self-assembly of the PS-grafted AuNPs. The silica coating improved the thermal stability and dispersibility of the AuNPs. By removing the "free" PS of the core, hollow particles with a hydrophobic cage having a AuNP corona and an inert silica shell were obtained. Also, Fe3O4 nanoparticles were encapsulated in the core, which resulted in magnetic core-shell hybrid particles by the same strategy. These particles have potential applications in biomolecular separation and high-temperature catalysis and as nanoreactors.

  9. A Hybrid Extended Kalman Filter as an Observer for a Pot-Electro-Magnetic Actuator

    Science.gov (United States)

    Schmidt, Simon; Mercorelli, Paolo

    2017-01-01

    This paper deals with an application in which a hybrid extended Kalman Filter (HEKF) is used to estimate state variables in a U-shaped electro-magnetic actuator to be used in mechanical systems. In this context a hybrid Kalman Filter is the one which switches between different models. The paper proposes a hybrid model for an extended Kalman Filter to be used as an observer to estimate the state and to control the force of the actuator. Applications include position, velocity and force control in automotive, engine and manufacturing systems. This work is focused on the estimation of state variables of the actuator. Simulated results show the effectiveness of the proposed approach.

  10. MODELLING AND TORQUE TRACKING CONTROL OF PERMANENT MAGNET SYNCHRONOUS MOTOR FOR HYBRID ELECTRIC VEHICLES

    Directory of Open Access Journals (Sweden)

    Mohd Sabirin Rahmat

    2013-06-01

    Full Text Available This paper presents a detailed derivation of a permanent magnet synchronous motor, which may be used as the electric power train for the simulation of a hybrid electric vehicle. A torque tracking control of the permanent magnet synchronous motor is developed by using an adaptive proportional-integral-derivative controller. Several tests such as step function, saw tooth function, sine wave function and square wave function were used in order to examine the performance of the proposed control structure. The effectiveness of the proposed controller was verified and compared with the same system under a PID controller and the desired control. The result of the observations shows that the proposed control structure proves to be effective in tracking the desired torque with a good response. The findings of this study will be considered in the design, optimisation and experimentation of series hybrid electric vehicle.

  11. Relativistic Adiabatic Time-Dependent Density Functional Theory Using Hybrid Functionals and Noncollinear Spin Magnetization

    DEFF Research Database (Denmark)

    Bast, Radovan; Jensen, Hans Jørgen Aagaard; Saue, Trond

    2009-01-01

    We report an implementation of adiabatic time-dependent density functional theory based on the 4-component relativistic Dirac-Coulomb Hamiltonian and a closed-shell reference. The implementation includes noncollinear spin magnetization and full derivatives of functionals, including hybrid...... and time reversal symmetry on trial vectors to obtain even better reductions in terms of memory and run time, and without invoking approximations. Further reductions are obtained by exploiting point group symmetries for D2h and subgroups in a symmetry scheme where symmetry reductions translate...... into reduction of algebra from quaternion to complex or real. For hybrid GGAs with noncollinear spin magnetization we derive a new computationally advantageous equation for the full second variational derivatives of such exchange-correlation functionals. We apply our implementation to calculations on the ns2...

  12. Dust-cyclotron and dust-lower-hybrid modes in self-gravitating magnetized dusty plasmas

    Indian Academy of Sciences (India)

    A K Banerjee; M N Alam; A A Mamun

    2003-07-01

    Theoretical investigation has been made on two different ultra-low-frequency electrostatic modes, namely, dust-cyclotron mode and dust-lower-hybrid mode, propagating perpendicular to the external magnetic field, in a self-gravitating magnetized two-fluid dusty plasma system. It has been shown that the effect of the self-gravitational force, acting on both dust grains and ions, significantly modifies the dispersion properties of these two electrostatic modes. The implications of these results to some space and astrophysical dusty plasma systems, especially to planetary ring-systems and cometary tails, are briefly mentioned.

  13. An integrated hybrid system for genetic analysis combining EWOD sample preparation and magnetic detection

    Energy Technology Data Exchange (ETDEWEB)

    Brennan, Des; Dinca, Mihai; Aherne, Margaret; Galvin, Paul [Tyndall National Institute, University College, Cork, Lee Maltings, Prospect Row, Cork (Ireland); Jary, Dorothee; Peponnet, Christine [CEA-LETI, Department of Technology for Biology and Health, 17 Avenue Des Martyrs, 38054 Grenoble (France); Cardosa, Filipe; Freitas, Paolo, E-mail: des.brennan@tyndall.ie [INESC-MN, Rua Alves Redol, 9, 1000-029 Lisbon (Portugal)

    2011-08-17

    Over the last decade microelectronic technologies have delivered significant advances in devices for point of care diagnostics. Complex microfluidic systems integrate components such as valves, pumps etc. to manipulate liquids. In recent years, the drive is to combine biochemical protocols in a single system, delivering 'sample in answer out'. An Electrowetting on Dielectric (EWOD) device offers the possibility to move and manipulate 64nl volumes implementing biochemical processes, while the magnetic sensor facilitates hybridisation detection. We outline an injection molding approach where EWOD and magnetic devices are integrated into a hybrid microfluidic system with the potential to implement 'sample in answer out' biological protocols.

  14. An integrated hybrid system for genetic analysis combining EWOD sample preparation and magnetic detection

    Science.gov (United States)

    Brennan, Des; Jary, Dorothee; Peponnet, Christine; Cardosa, Filipe; Freitas, Paolo; Dinca, Mihai; Aherne, Margaret; Galvin, Paul

    2011-08-01

    Over the last decade microelectronic technologies have delivered significant advances in devices for point of care diagnostics. Complex microfluidic systems integrate components such as valves, pumps etc. to manipulate liquids. In recent years, the drive is to combine biochemical protocols in a single system, delivering "sample in answer out". An Electrowetting on Dielectric (EWOD) device offers the possibility to move and manipulate 64nl volumes implementing biochemical processes, while the magnetic sensor facilitates hybridisation detection. We outline an injection molding approach where EWOD and magnetic devices are integrated into a hybrid microfluidic system with the potential to implement "sample in answer out" biological protocols.

  15. Plasma environment of magnetized asteroids: a 3-D hybrid simulation study

    Directory of Open Access Journals (Sweden)

    S. Simon

    2006-03-01

    Full Text Available The interaction of a magnetized asteroid with the solar wind is studied by using a three-dimensional hybrid simulation code (fluid electrons, kinetic ions. When the obstacle's intrinsic magnetic moment is sufficiently strong, the interaction region develops signs of magnetospheric structures. On the one hand, an area from which the solar wind is excluded forms downstream of the obstacle. On the other hand, the interaction region is surrounded by a boundary layer which indicates the presence of a bow shock. By analyzing the trajectories of individual ions, it is demonstrated that kinetic effects have global consequences for the structure of the interaction region.

  16. Torque Analysis of Permanent Magnet Hybrid Stepper Motor using Finite Element Method for Different Design Topologies

    Directory of Open Access Journals (Sweden)

    E.V.C Sekhara Rao

    2012-01-01

    Full Text Available This paper discusses about permanent magnet hybrid stepper motor magnetic circuit using finite element model for different geometric designs like uniform air-gap, non uniform air-gap, for different air-gap lengths, different tooth pitches and extra teeth on stator using PDE toolbox of Matlab at different current densities. Implementing these results in equivalent circuit model (permeance model, motor performance is analyzed for an existing motor for steady state conditions. These results suggest modifications for better performance of the PMH stepper motor like reduction of cogging torque and improvement in steady state torque with minimum THD.

  17. Research on Operation Principle and Control of Novel Hybrid Excitation Bearingless Permanent Magnet Generator

    Directory of Open Access Journals (Sweden)

    Huangqiu Zhu

    2016-08-01

    Full Text Available Under the condition of load changing, the magnetic field of traditional permanent magnet generators (PMG is hard to be adjusted, and the mechanical bearings are significantly worn. To overcome the drawbacks above, a novel hybrid excitation bearingless permanent magnet generator (HEBPMG is proposed in this paper, which has integrated the merits of hybrid excitation permanent magnet generators and magnetic bearings. Firstly, the structure and winding configuration of the HEBPMG are introduced, and then the principles of radial suspension and power generation are presented. The suspension principle as well as power generation principle is analyzed in this paper. Then, the flux linkage and induced voltage equations are derived, and the accurate mathematical model of radial suspension force is built based on the Maxwell tensor method. Subsequently, by means of the finite element analysis software-ANSYS Maxwell, the corresponding electromagnetic characteristics are analyzed to verify the correctness of the mentioned models. In addition, a compensation control strategy based on flux-linkage observation is proposed to solve the problems of unstable suspension force and generating voltage under variable load condition in this paper. Meanwhile, the corresponding control system is constructed and its feasibility is validated by simulation results. Finally, an experimental prototype of a 2.2 kW HEBPMG is tested. Experimental researches show that the HEBPMG can operate steadily under variable load condition and possess good suspension performance and power generation quality.

  18. Bio-bar-code functionalized magnetic nanoparticle label for ultrasensitive flow injection chemiluminescence detection of DNA hybridization.

    Science.gov (United States)

    Bi, Sai; Zhou, Hong; Zhang, Shusheng

    2009-10-07

    A signal amplification strategy based on bio-bar-code functionalized magnetic nanoparticles as labels holds promise to improve the sensitivity and detection limit of the detection of DNA hybridization and single-nucleotide polymorphisms by flow injection chemiluminescence assays.

  19. Controllable synthesis, magnetism and solubility enhancement of graphene nanosheets/magnetite hybrid material by covalent bonding.

    Science.gov (United States)

    Zhan, Yingqing; Yang, Xulin; Meng, Fanbin; Wei, Junji; Zhao, Rui; Liu, Xiaobo

    2011-11-01

    Hybrids of Fe(3)O(4) nanoparticles and surface-modified graphene nanosheets (GNs) were synthesized by a two-step process. First, graphene nanosheets were modified by SOCl(2) and 4-aminophenoxyphthalonitrile to introduce nitrile groups on their surface. Second, the nitrile groups of surface-modified graphene nanosheets were reacted with ferric ions on the surface of Fe(3)O(4) with the help of relatively high boiling point solvent ethylene glycol to form a GNs/Fe(3)O(4) hybrid. The covalent attachment of Fe(3)O(4) nanoparticles on the graphene nanosheet surface was confirmed by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), energy-dispersive X-ray spectrometer (EDS) and scanning electron microscopy (SEM). TEM and HRTEM observations indicated that the sizes of the nanoparticles and their coverage density on GNs could be easily controlled by changing the concentration of the precursor and the weight ratio to GNs. Magnetic measurements showed that magnetization of the hybrid materials is strongly influenced by the reaction conditions. Chemically bonded by phthalocyanine, the solubility of as-synthesized GNs/Fe(3)O(4) hybrid materials was greatly enhanced, which was believed to have potential for applications in the fields of composites, wastewater treatment and biomaterials.

  20. The topological structure of the integral quantum Hall effect in magnetic semiconductor-superconductor hybrids

    Institute of Scientific and Technical Information of China (English)

    Ren Ji-Rong; Zhu Hui

    2009-01-01

    An unconventional integer quantum Hall regime was found in magnetic semiconductor-superconductor hybrids.By making use of the decomposition of the gauge potential on a U(1) principal fibre bundle over k-space, we study the topological structure of the integral Hall conductance. It is labeled by the Hopf index β and the Brouwer degree η. The Hall conductance topological current and its evolution is discussed.

  1. Magneto-rheological response of elastomer composites with hybrid-magnetic fillers

    Science.gov (United States)

    Aloui, Sahbi; Klüppel, Manfred

    2015-02-01

    We study the magneto-rheological response of hybrid-magnetic elastomer composites consisting of two different magnetic filler particles at fixed overall concentration. Thereby, we focus on an optimization of mechanical and magnetic properties by combining highly reinforcing magnetic nano-particles (MagSilica) with micro-sized carbonyl-iron particles (CIP), which exhibit high switch ability in a magnetic field. We observe a symbiotic interaction of both filler types, especially in the case when an orientation of the magnetic filler particles is achieved due to curing in an external magnetic field. The orientation effect is significant only for the micro-sized CIP particles with high saturation magnetization, indicating that the induced magnetic moment for the nano-sized particles is too small for delivering sufficient attraction between the particles in an external magnetic field. A pronounced switching behavior is observed for the non-cross-linked melts with 15 and 20 vol.% CIP, whereby the small strain modulus increases by more than 50%. For the sample without the coupling agent silane, one even observes a relative modulus increase of about 140%, which can be related to the combined effect of a higher mobility of the particles without a silane layer and the ability of the particles to come in close contact when they are arranged in strings along the field lines. For the cross-linked samples, a maximum switching effect of about 30% is achieved for the system with pure CIP. This magneto-sensitivity decreases successively if CIP is replaced by MagSilica, while the tensile strength of the systems increases significantly. The use of silane reduces the switching effect, but it is necessary for a good mechanical performance by delivering strong chemical bonding of the magnetic filler particles to the polymer matrix.

  2. PRINCIPLES AND PARAMETER DESIGN FOR AC-DC THREE-DEGREE FREEDOM HYBRID MAGNETIC BEARINGS

    Institute of Scientific and Technical Information of China (English)

    ZHU Huangqiu; XIE Zhiyi; ZHU Dehong

    2006-01-01

    To simplify the mechanical structure, decrease the overall system size of the 3-degree freedom axial-radial magnetic bearings and reduce the manufacturing costs as well as operating costs,an innovated AC-DC 3-degree freedom hybrid magnetic bearing is proposed, which is driven by a DC amplifier in axial direction and a 3-phase power converter in radial directions respectively, and the axial and radial bias magnetic fluxes are provided with a common radial polarized permanent magnet ring. The principle producing magnetic suspension forces is introduced. By using equivalent magnetic circuit method, the calculation formulas of magnetic suspension forces and the mathematics models of the system are deduced. Nonlinearities of suspension forces and cross coupling between different degree freedoms are studied further by calculating the suspension forces at different displacements and control currents to validate the feasibility of the mathematics model. Then based on the mathematics models of the bearing, a control method of this novel bearing is designed. Lastly, the methods on parameter design and calculations of the bearing are presented, and an applicable prototype is simulated to analyze the magnetic path by using finite element analysis. The theory analysis and simulation results have shown that this magnetic bearing incorporates the merits of 3-phase AC drive, permanent magnet flux biased and axial-radial combined control, and reduces overall system size and has higher efficiency and lower cost. This innovated magnetic bearing has a wide application in super-speed and super-precision numerical control machine tools, bearingless motors, high-speed flywheels, satellites, etc.

  3. Trapping mid-infrared rays in a lossy film with the Berreman mode, epsilon near zero mode, and magnetic polaritons.

    Science.gov (United States)

    Chen, Yu-Bin; Chiu, Feng-Cheng

    2013-09-09

    Triple mechanisms were employed to trap mid-infrared (mid-IR) rays within a semi-transparent SiO(2) film sandwiched between gold gratings and a gold substrate. Dimensions of four absorbers were explicitly determined using an LC (inductor-capacitor) circuit model considering the role transition of SiO(2) film. The film behaves as a capacitance and an inductance when the real part of relative electric permittivity for SiO(2) is positive and negative, respectively. At the normal incidence of transverse magnetic waves, every absorptance spectrum of absorbers showed a peak at wavelength λ = 10 μm due to the first mode excitation of magnetic polaritons (MP). At oblique incidence, the Berreman mode led to another peak at λ = 8 μm while its bandwidth was expanded with epsilon near zero mode excited by diffracted waves. The full-width-at-half-maximum of both peaks exceeded 0.6 μm thanks to the SiO(2) loss. Other minor absorptance peaks in the mid-IR were caused by variants of the same MP mode.

  4. Dark-resonance Doppler cooling and high fluorescence in trapped Ca-43 ions at intermediate magnetic field

    CERN Document Server

    Allcock, D T C; Sepiol, M A; Janacek, H A; Ballance, C J; Steane, A M; Lucas, D M; Stacey, D N

    2015-01-01

    We demonstrate simple and robust methods for Doppler cooling and obtaining high fluorescence from trapped 43Ca+ ions at a magnetic field of 146 Gauss. This field gives access to a magnetic-field-independent "atomic clock" qubit transition within the ground level hyperfine structure of the ion, but also causes the complex internal structure of the 64 states relevant to Doppler cooling to be spread over many times the atomic transition line-width. Using a time-dependent optical Bloch equation simulation of the system we develop a simple scheme to Doppler-cool the ion on a two-photon dark resonance, which is robust to typical experimental variations in laser intensities, detunings and polarizations. We experimentally demonstrate cooling to a temperature of 0.3 mK, slightly below the Doppler limit for the corresponding two-level system, and then use Raman sideband laser cooling to cool further to the ground states of the ion's radial motional modes. These methods will enable two-qubit entangling gates with this i...

  5. Effect of c-f hybridization on electric and magnetic properties of some Heavy Fermion (HF) systems

    Energy Technology Data Exchange (ETDEWEB)

    Sahoo, J., E-mail: jitendrasahoo2008@gmail.com [Regional Office of Vocational Education, Sambalpur, Odisha -768 004 (India); Nayak, P. [School of Physics, Sambalpur University, Sambalpur, Odisha - 768 019 (India)

    2017-02-01

    Representing the heavy fermion systems by the Periodic Anderson Model (PAM), we have used Zubarev technique to see the effect of c-f hybridization on the temperature dependence of resistivity and magnetic susceptibility. The calculated resistivity and magnetic susceptibility show the general features observed in these materials experimentally. Further, we have shown how the strength of hybridization as well as the position of the f-level affects both the properties and the Kondo temperature of these systems.

  6. Effect of c-f hybridization on electric and magnetic properties of some Heavy Fermion (HF) systems

    Science.gov (United States)

    Sahoo, J.; Nayak, P.

    2017-02-01

    Representing the heavy fermion systems by the Periodic Anderson Model (PAM), we have used Zubarev technique to see the effect of c-f hybridization on the temperature dependence of resistivity and magnetic susceptibility. The calculated resistivity and magnetic susceptibility show the general features observed in these materials experimentally. Further, we have shown how the strength of hybridization as well as the position of the f-level affects both the properties and the Kondo temperature of these systems.

  7. Development of a Hybrid Piezo Natural Rubber Piezoelectricity and Piezoresistivity Sensor with Magnetic Clusters Made by Electric and Magnetic Field Assistance and Filling with Magnetic Compound Fluid

    Directory of Open Access Journals (Sweden)

    Kunio Shimada

    2017-02-01

    Full Text Available Piezoelements used in robotics require large elasticity and extensibility to be installed in an artificial robot skin. However, the piezoelements used until recently are vulnerable to large forces because of the thin solid materials employed. To resolve this issue, we utilized a natural rubber and applied our proposed new method of aiding with magnetic and electric fields as well as filling with magnetic compound fluid (MCF and doping. We have verified the piezoproperties of the resulting MCF rubber. The effect of the created magnetic clusters is featured in a new two types of multilayered structures of the piezoelement. By measuring the piezoelectricity response to pressure, the synergetic effects of the magnetic clusters, the doping and the electric polymerization on the piezoelectric effect were clarified. In addition, by examining the relation between the piezoelectricity and the piezoresistivity created in the MCF piezo element, we propose a hybrid piezoelement.

  8. Development of a Hybrid Piezo Natural Rubber Piezoelectricity and Piezoresistivity Sensor with Magnetic Clusters Made by Electric and Magnetic Field Assistance and Filling with Magnetic Compound Fluid.

    Science.gov (United States)

    Shimada, Kunio; Saga, Norihiko

    2017-02-10

    Piezoelements used in robotics require large elasticity and extensibility to be installed in an artificial robot skin. However, the piezoelements used until recently are vulnerable to large forces because of the thin solid materials employed. To resolve this issue, we utilized a natural rubber and applied our proposed new method of aiding with magnetic and electric fields as well as filling with magnetic compound fluid (MCF) and doping. We have verified the piezoproperties of the resulting MCF rubber. The effect of the created magnetic clusters is featured in a new two types of multilayered structures of the piezoelement. By measuring the piezoelectricity response to pressure, the synergetic effects of the magnetic clusters, the doping and the electric polymerization on the piezoelectric effect were clarified. In addition, by examining the relation between the piezoelectricity and the piezoresistivity created in the MCF piezo element, we propose a hybrid piezoelement.

  9. Development of a Hybrid Piezo Natural Rubber Piezoelectricity and Piezoresistivity Sensor with Magnetic Clusters Made by Electric and Magnetic Field Assistance and Filling with Magnetic Compound Fluid

    Science.gov (United States)

    Shimada, Kunio; Saga, Norihiko

    2017-01-01

    Piezoelements used in robotics require large elasticity and extensibility to be installed in an artificial robot skin. However, the piezoelements used until recently are vulnerable to large forces because of the thin solid materials employed. To resolve this issue, we utilized a natural rubber and applied our proposed new method of aiding with magnetic and electric fields as well as filling with magnetic compound fluid (MCF) and doping. We have verified the piezoproperties of the resulting MCF rubber. The effect of the created magnetic clusters is featured in a new two types of multilayered structures of the piezoelement. By measuring the piezoelectricity response to pressure, the synergetic effects of the magnetic clusters, the doping and the electric polymerization on the piezoelectric effect were clarified. In addition, by examining the relation between the piezoelectricity and the piezoresistivity created in the MCF piezo element, we propose a hybrid piezoelement. PMID:28208625

  10. Trapped antihydrogen

    CERN Document Server

    Butler, E; Ashkezari, M D; Baquero-Ruiz, M; Bertsche, W; Bowe, P D; Cesar, C L; Chapman, S; Charlton, M; Deller, A; Eriksson, S; Fajans, J; Friesen, T; Fujiwara, M C; Gill, D R; Gutierrez, A; Hangst, J S; Hardy, W N; Hayden, M E; Humphries, A J; Hydomako, R; Jenkins, M J; Jonsell, S; Jørgensen, L V; Kemp, S L; Kurchaninov, L; Madsen, N; Menary, S; Nolan, P; Olchanski, K; Olin, A; Povilus, A; Pusa, P; Rasmussen, C Ø; Robicheaux, F; Sarid, E; Seif el Nasr, S; Silveira, D M; So, C; Storey, J W; Thompson, R I; van der Werf, D P; Wurtele, J S; Yamazaki,Y

    2012-01-01

    Precision spectroscopic comparison of hydrogen and antihydrogen holds the promise of a sensitive test of the Charge-Parity-Time theorem and matter-antimatter equivalence. The clearest path towards realising this goal is to hold a sample of antihydrogen in an atomic trap for interrogation by electromagnetic radiation. Achieving this poses a huge experimental challenge, as state-of-the-art magnetic-minimum atom traps have well depths of only ∼1 T (∼0.5 K for ground state antihydrogen atoms). The atoms annihilate on contact with matter and must be ‘born’ inside the magnetic trap with low kinetic energies. At the ALPHA experiment, antihydrogen atoms are produced from antiprotons and positrons stored in the form of non-neutral plasmas, where the typical electrostatic potential energy per particle is on the order of electronvolts, more than 104 times the maximum trappable kinetic energy. In November 2010, ALPHA published the observation of 38 antiproton annihilations due to antihydrogen atoms that had been ...

  11. Orientation and thickness dependence of magnetic levitation force and trapped magnetic field of single grain YBa{sub 2}Cu{sub 3}O{sub 7-y} bulk superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Y.; Go, S. J.; Joo, H. T. [Korea Science Academy of Korea Advanced Institute of Science and Technology, Pusan (Korea, Republic of); Lee, Y. J.; Park, S. D.; Jun, B. H.; KIm, C. J. [Neutron Utilization Technology Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2017-03-15

    The effects of the crystallographic orientation and sample thickness on the magnetic levitation forces (F) and trapped magnetic field (B) of single grain YBCO bulk superconductors were examined. Single grain YBCO samples with a (001), (110) or (100) surface were used as the test samples. The samples used for the force-distance (F-d) measurement were cooled at 77 K without a magnetic field (zero field cooling, ZFC), whereas the samples used for the B measurement were cooled under the external magnetic field of a Nd-B-Fe permanent magnet (field cooling, FC). It was found that F and B of the (001) surface were higher than those of the (110) or (100) surface, which is attributed to the higher critical current density (J{sub c}) of the (001) surface. For the (001) samples with t=5–18 mm, the maximum magnetic levitation forces (F{sub max}s) of the ZFC samples were larger than 40 N. About 80% of the applied magnetic field was trapped in the FC samples. However, the F and B decreased rapidly as t decreased below 5 mm. There exists a critical sample thickness (t=5 mm for the experimental condition of this study) for maintaining the large levitation/trapping properties, which is dependent on the material properties and magnitude of the external magnetic fields.

  12. Development of a Hybrid Magnetic Resonance and Ultrasound Imaging System

    Directory of Open Access Journals (Sweden)

    Victoria Sherwood

    2014-01-01

    Full Text Available A system which allows magnetic resonance (MR and ultrasound (US image data to be acquired simultaneously has been developed. B-mode and Doppler US were performed inside the bore of a clinical 1.5 T MRI scanner using a clinical 1–4 MHz US transducer with an 8-metre cable. Susceptibility artefacts and RF noise were introduced into MR images by the US imaging system. RF noise was minimised by using aluminium foil to shield the transducer. A study of MR and B-mode US image signal-to-noise ratio (SNR as a function of transducer-phantom separation was performed using a gel phantom. This revealed that a 4 cm separation between the phantom surface and the transducer was sufficient to minimise the effect of the susceptibility artefact in MR images. MR-US imaging was demonstrated in vivo with the aid of a 2 mm VeroWhite 3D-printed spherical target placed over the thigh muscle of a rat. The target allowed single-point registration of MR and US images in the axial plane to be performed. The system was subsequently demonstrated as a tool for the targeting and visualisation of high intensity focused ultrasound exposure in the rat thigh muscle.

  13. Hybrid Materials Based on Magnetic Layered Double Hydroxides: A Molecular Perspective.

    Science.gov (United States)

    Abellán, Gonzalo; Martí-Gastaldo, Carlos; Ribera, Antonio; Coronado, Eugenio

    2015-06-16

    Design of functional hybrids lies at the very core of synthetic chemistry as it has enabled the development of an unlimited number of solids displaying unprecedented or even improved properties built upon the association at the molecular level of quite disparate components by chemical design. Multifunctional hybrids are a particularly appealing case among hybrid organic/inorganic materials. Here, chemical knowledge is used to deploy molecular components bearing different functionalities within a single solid so that these properties can coexist or event interact leading to unprecedented phenomena. From a molecular perspective, this can be done either by controlled assembly of organic/inorganic molecular tectons into an extended architecture of hybrid nature or by intercalation of organic moieties within the empty channels or interlamellar space offered by inorganic solids with three-dimensional (MOFs, zeolites, and mesoporous hosts) or layered structures (phosphates, silicates, metal dichalcogenides, or anionic clays). This Account specifically illustrates the use of layered double hydroxides (LDHs) in the preparation of magnetic hybrids, in line with the development of soft inorganic chemistry processes (also called "Chimie Douce"), which has significantly contributed to boost the preparation hybrid materials based on solid-state hosts and subsequent development of applications. Several features sustain the importance of LDHs in this context. Their magnetism can be manipulated at a molecular level by adequate choice of constituting metals and interlayer separation for tuning the nature and extent of magnetic interactions across and between planes. They display unparalleled versatility in accommodating a broad range of anionic species in their interlamellar space that encompasses not only simple anions but chemical systems of increasing dimensionality and functionalities. Their swelling characteristics allow for their exfoliation in organic solvents with high

  14. DFT calculations of magnetic parameters for molybdenum complexes and hydroxymethyl intermediates trapped on silica surface

    Science.gov (United States)

    Sojka, Zbigniew; Pietrzyk, Piotr

    2006-03-01

    Density functional theory (DFT) calculations of EPR parameters and their structure sensitivity for selected surface paramagnetic species involved in oxidative dehydrogenation of methanol over silica grafted molybdenum catalyst were investigated. Two surface complexes, Mo 4 c/SiO 2 and {O -sbnd Mo 4 c}/SiO 2, as well as rad CH 2OH radical trapped on the SiO 2 matrix were taken as the examples. The spin-restricted zeroth order regular approximation (ZORA) implemented in the Amsterdam Density Functional suite was used to calculate the electronic g tensor for those species. The predicted values were in satisfactory agreement with experimental EPR results. Five different coordination modes of the rad CH 2OH radical on the silica surface were considered and the isotropic 13C, 17O, and 1H hyperfine coupling constants (HFCC) of the resultant surface complexes were calculated. Structure sensitivity of the HFCC values was discussed in terms of the angular deformations caused by hydrogen bonding with the silica surface.

  15. Numerical analysis of applied magnetic field dependence in Malmberg-Penning Trap for compact simulator of energy driver in heavy ion fusion

    Science.gov (United States)

    Sato, T.; Park, Y.; Soga, Y.; Takahashi, K.; Sasaki, T.; Kikuchi, T.; Harada, Nob

    2016-05-01

    To simulate a pulse compression process of space charge dominated beams in heavy ion fusion, we have demonstrated a multi-particle numerical simulation as an equivalent beam using the Malmberg-Penning trap device. The results show that both transverse and longitudinal velocities as a function of external magnetic field strength are increasing during the longitudinal compression. The influence of space-charge effect, which is related to the external magnetic field, was observed as the increase of high velocity particles at the weak external magnetic field.

  16. Bulk high-T{sub c} superconductors with drilled holes: how to arrange the holes to maximize the trapped magnetic flux?

    Energy Technology Data Exchange (ETDEWEB)

    Lousberg, Gregory P [SUPRATECS Research Group, Department of Electrical Engineering and Computer Science (B28), University of Liege (Belgium); Ausloos, M [SUPRATECS, Department of Physics (B5), University of Liege (Belgium); Vanderbemden, Ph [SUPRATECS Research Group, Department of Electrical Engineering and Computer Science (B28), University of Liege (Belgium); Vanderheyden, B [SUPRATECS Research Group, Department of Electrical Engineering and Computer Science (B28), University of Liege (Belgium)

    2008-02-15

    Drilling holes in a bulk high-T{sub c} superconductor enhances the oxygen annealing and the heat exchange with the cooling liquid. However, drilling holes also reduces the amount of magnetic flux that can be trapped in the sample. In this paper, we use the Bean model to study the magnetization and the current line distribution in drilled samples, as a function of the hole positions. A single hole perturbs the critical current flow over an extended region that is bounded by a discontinuity line, where the direction of the current density changes abruptly. We demonstrate that the trapped magnetic flux is maximized if the centre of each hole is positioned on one of the discontinuity lines produced by the neighbouring holes. For a cylindrical sample, we construct a polar triangular hole pattern that exploits this principle; in such a lattice, the trapped field is {approx}20% higher than in a squared lattice, for which the holes do not lie on discontinuity lines. This result indicates that one can simultaneously enhance the oxygen annealing, the heat transfer and maximize the trapped field.

  17. Qualitative analysis of major constituents from Xue Fu Zhu Yu Decoction using ultra high performance liquid chromatography with hybrid ion trap time-of-flight mass spectrometry.

    Science.gov (United States)

    Fu, Chunyan; Xia, Zian; Liu, Yonghui; Lu, Hongmei; Zhang, Zhimin; Wang, Yang; Fan, Xiaqiong

    2016-09-01

    Xue Fu Zhu Yu Decoction, a famous formula that has been used for treating many blood stasis-caused diseases for many centuries, comprises 11 kinds of traditional Chinese medicines. A convenient, efficient, and rapid analytical method was developed to simultaneously determine the major compounds in this decoction. An ultra-high performance liquid chromatography with hybrid ion trap time-of-flight mass spectrometry method was used to rapidly separate and detect the major constituents of the decoction. Using this technique, we identified or tentatively identified 34 compounds, including 21 flavonoids, 5 terpenoids, 3 organic acids, 2 lactones, 1 alkaloid, 1 amino acid, and 1 cyanogenic glycoside. The MS analysis of these constituents was described in detail. Findings may contribute to future metabolic and pharmacokinetic studies of this medicine.

  18. A dual-channel flux-switching permanent magnet motor for hybrid electric vehicles

    Science.gov (United States)

    Hua, Wei; Wu, Zhongze; Cheng, Ming; Wang, Baoan; Zhang, Jianzhong; Zhou, Shigui

    2012-04-01

    The flux-switching permanent magnet (FSPM) motor is a relatively novel brushless machine having both magnets and concentrated windings in the stator, which exhibits inherently sinusoidal PM flux-linkage, back-EMF waveforms, and high torque capability. However, in the application of hybrid electric vehicles, it is essential to prevent magnets and armature windings moving in radial direction due to the possible vibration during operation, and to ensure fault-tolerant capability. Hence, in this paper based on an original FSPM motor, a dual-channel FSPM (DC-FSPM) motor with modified structure to fix both armature windings and magnets and improved reliability is proposed for a practical 10 kW integral starter/generator (ISG) in hybrid electric vehicles. The influences of different solutions and the end-effect on the static characteristics, are evaluated based on the 2D and 3D finite element analysis, respectively. Finally, both the predicted and experimental results, compared with a prototype DC-FSPM motor and an interior PM motor used in Honda Civic, confirm that the more sinusoidal back-EMF waveform and lower torque ripple can be achieved in the DC-FSPM motor, whereas the torque is smaller under the same coil current.

  19. Optimization design of an interior permanent-magnet synchronous machine for a hybrid hydraulic excavator

    Institute of Scientific and Technical Information of China (English)

    Qi-huai CHEN; Qing-feng WANG; Tao WANG

    2015-01-01

    A hybrid power transmission system (HPTS) is a promising way to save energy in a hydraulic excavator and the electric machine is one of the key components of the system. In this paper, a design process for permanent-magnet synchronous machines (PMSMs) in a hybrid hydraulic excavator (HHE) is presented based on the analysis of the working conditions and requirements of an HHE. A parameterized design approach, which combines the analytical model and the 2D finite element method (FEM), is applied to the electric machine to improve the design efficiency and accuracy. The analytical model is employed to optimize the electric machine efficiency and obtain the stator dimension and flux density distribution. The rotor is designed with the FEM to satisfy the flux requirements obtained in stator design. The rotor configuration of the PMSM employs an interior magnet structure, thus resulting in some inverse saliency, which allows for much higher values in magnetic flux density. To reduce the rotor leakage, a disconnected type silicon steel block structure is adopted. To improve the air gap flux density distribution, the trapezoid permanent magnet (PM) and centrifugal rotor structure are applied to PMSM. Demagnetization and armature reactions are also taken into consideration and calculated by the FEM. A prototype of the newly designed electric machine has been fabri-cated and tested on the experimental platform. The analytical design results are validated by measurements.

  20. Detection of a magnetic bead by hybrid nanodevices using scanning gate microscopy

    Directory of Open Access Journals (Sweden)

    H. Corte-León

    2016-05-01

    Full Text Available Hybrid ferromagnetic(Py/non-magnetic metal(Au junctions with a width of 400 nm are studied by magnetotransport measurements, magnetic scanning gate microscopy (SGM with a magnetic bead (MB attached to the probe, and micromagnetic simulations. In the transverse geometry, the devices demonstrate a characteristic magnetoresistive behavior that depends on the direction of the in plane magnetic field, with minimum/maximum variation when the field is applied parallel/perpendicular to the Py wire. The SGM is performed with a NdFeB bead of 1.6 μm diameter attached to the scanning probe. Our results demonstrate that the hybrid junction can be used to detect this type of MB. A rough approximation of the sensing volume of the junction has the shape of elliptical cylinder with the volume of ∼1.51 μm3. Micromagnetic simulations coupled to a magnetotransport model including anisotropic magnetoresistance and planar Hall effects are in good agreement with the experimental findings, enabling the interpretation of the SGM images.

  1. Detection of a magnetic bead by hybrid nanodevices using scanning gate microscopy

    Science.gov (United States)

    Corte-León, H.; Krzysteczko, P.; Marchi, F.; Motte, J.-F.; Manzin, A.; Schumacher, H. W.; Antonov, V.; Kazakova, O.

    2016-05-01

    Hybrid ferromagnetic(Py)/non-magnetic metal(Au) junctions with a width of 400 nm are studied by magnetotransport measurements, magnetic scanning gate microscopy (SGM) with a magnetic bead (MB) attached to the probe, and micromagnetic simulations. In the transverse geometry, the devices demonstrate a characteristic magnetoresistive behavior that depends on the direction of the in plane magnetic field, with minimum/maximum variation when the field is applied parallel/perpendicular to the Py wire. The SGM is performed with a NdFeB bead of 1.6 μm diameter attached to the scanning probe. Our results demonstrate that the hybrid junction can be used to detect this type of MB. A rough approximation of the sensing volume of the junction has the shape of elliptical cylinder with the volume of ˜1.51 μm3. Micromagnetic simulations coupled to a magnetotransport model including anisotropic magnetoresistance and planar Hall effects are in good agreement with the experimental findings, enabling the interpretation of the SGM images.

  2. First Attempts at Antihydrogen Trapping in ALPHA

    Science.gov (United States)

    Andresen, G. B.; Bertsche, W.; Bowe, P. D.; Bray, C. C.; Butler, E.; Cesar, C. L.; Chapman, S.; Charlton, M.; Fajans, J.; Fujiwara, M. C.; Funakoshi, R.; Gill, D. R.; Hangst, J. S.; Hardy, W. N.; Hayano, R. S.; Hayden, M. E.; Humphries, A. J.; Hydomako, R.; Jenkins, M. J.; Jørgensen, L. V.; Kurchaninov, L.; Lambo, R.; Madsen, N.; Nolan, P.; Olchanski, K.; Olin, A.; Page, R. D.; Povilus, A.; Pusa, P.; Robicheaux, F.; Sarid, E.; El Nasr, S. Seif; Silveira, D. M.; Storey, J. W.; Thompson, R. I.; van der Werf, D. P.; Wurtele, J. S.; Yamazaki, Y.

    2008-08-01

    The ALPHA apparatus is designed to produce and trap antihydrogen atoms. The device comprises a multifunction Penning trap and a superconducting, neutral atom trap having a minimum-B configuration. The atom trap features an octupole magnet for transverse confinement and solenoidal mirror coils for longitudinal confinement. The magnetic trap employs a fast shutdown system to maximize the probability of detecting the annihilation of released antihydrogen. In this article we describe the first attempts to observe antihydrogen trapping.

  3. Characterization of Extremely Low Frequency Magnetic Fields from Diesel, Gasoline and Hybrid Cars under Controlled Conditions

    Directory of Open Access Journals (Sweden)

    Ronen Hareuveny

    2015-01-01

    Full Text Available This study characterizes extremely low frequency (ELF magnetic field (MF levels in 10 car models. Extensive measurements were conducted in three diesel, four gasoline, and three hybrid cars, under similar controlled conditions and negligible background fields. Averaged over all four seats under various driving scenarios the fields were lowest in diesel cars (0.02 μT, higher for gasoline (0.04–0.05 μT and highest in hybrids (0.06–0.09 μT, but all were in-line with daily exposures from other sources. Hybrid cars had the highest mean and 95th percentile MF levels, and an especially large percentage of measurements above 0.2 μT. These parameters were also higher for moving conditions compared to standing while idling or revving at 2500 RPM and higher still at 80 km/h compared to 40 km/h. Fields in non-hybrid cars were higher at the front seats, while in hybrid cars they were higher at the back seats, particularly the back right seat where 16%–69% of measurements were greater than 0.2 μT. As our results do not include low frequency fields (below 30 Hz that might be generated by tire rotation, we suggest that net currents flowing through the cars’ metallic chassis may be a possible source of MF. Larger surveys in standardized and well-described settings should be conducted with different types of vehicles and with spectral analysis of fields including lower frequencies due to magnetization of tires.

  4. Existence of Global Weak Solutions to a Hybrid Vlasov-MHD Model for Magnetized Plasmas

    CERN Document Server

    Cheng, Bin; Tronci, Cesare

    2016-01-01

    We prove the global-in-time existence of large-data finite-energy weak solutions to an incompressible hybrid Vlasov-magnetohydrodynamic model in three space dimensions. The model couples three essential ingredients of magnetized plasmas: a transport equation for the probability density function, which models energetic rarefied particles of one species; the incompressible Navier--Stokes system for the bulk fluid; and a parabolic evolution equation, involving magnetic diffusivity, for the magnetic field. The physical derivation of our model is given. It is also shown that the weak solution, whose existence is established, has nonincreasing total energy, and that it satisfies a number of physically relevant properties, including conservation of the total momentum, conservation of the total mass, and nonnegativity of the probability density function for the energetic particles. The proof is based on a one-level approximation scheme, which is carefully devised to avoid increase of the total energy for the sequence...

  5. Zero Power Levitation Control of Hybrid Electro-Magnetic Levitation System by Load Observer

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Youn Hyun; Lee, Ju [Hanyang University, Seoul (Korea)

    2001-06-01

    This paper introduces the scheme that improve the control performance of electromagnetic levitation system with zero power controller. Magnetic levitation is used widely, but the electromagnetic force has nonlinear characteristics because it is proportioned to a square of the magnetic flux density and it is in inverse proportion to a square of the air gap. So, it is complicate and difficult to control the electromagnetic force. Besides, it is more difficult to control if the equivalent gap is unknown in case of zero power control. Therefore, this paper proposed the hybrid electro-magnetic levitation control method in which the variable load is estimated by using a load observer and its system is controlled at a new zero power equilibrium air gap position. Also it is confirmed that the proposed control method improve the control performance through simulation and experiment. (author). 10 refs., 17 figs., 1 tab.

  6. Strain-controlled magnetic domain wall propagation in hybrid piezoelectric/ferromagnetic structures

    Science.gov (United States)

    Lei, Na; Devolder, Thibaut; Agnus, Guillaume; Aubert, Pascal; Daniel, Laurent; Kim, Joo-Von; Zhao, Weisheng; Trypiniotis, Theodossis; Cowburn, Russell P.; Chappert, Claude; Ravelosona, Dafiné; Lecoeur, Philippe

    2013-01-01

    The control of magnetic order in nanoscale devices underpins many proposals for integrating spintronics concepts into conventional electronics. A key challenge lies in finding an energy-efficient means of control, as power dissipation remains an important factor limiting future miniaturization of integrated circuits. One promising approach involves magnetoelectric coupling in magnetostrictive/piezoelectric systems, where induced strains can bear directly on the magnetic anisotropy. While such processes have been demonstrated in several multiferroic heterostructures, the incorporation of such complex materials into practical geometries has been lacking. Here we demonstrate the possibility of generating sizeable anisotropy changes, through induced strains driven by applied electric fields, in hybrid piezoelectric/spin-valve nanowires. By combining magneto-optical Kerr effect and magnetoresistance measurements, we show that domain wall propagation fields can be doubled under locally applied strains. These results highlight the prospect of constructing low-power domain wall gates for magnetic logic devices.

  7. Neutral atom traps.

    Energy Technology Data Exchange (ETDEWEB)

    Pack, Michael Vern

    2008-12-01

    This report describes progress in designing a neutral atom trap capable of trapping sub millikelvin atom in a magnetic trap and shuttling the atoms across the atom chip from a collection area to an optical cavity. The numerical simulation and atom chip design are discussed. Also, discussed are preliminary calculations of quantum noise sources in Kerr nonlinear optics measurements based on electromagnetically induced transparency. These types of measurements may be important for quantum nondemolition measurements at the few photon limit.

  8. Magnetic amphiphilic hybrid carbon nanotubes containing N-doped and undoped sections: powerful tensioactive nanostructures

    Science.gov (United States)

    Purceno, Aluir D.; Machado, Bruno F.; Teixeira, Ana Paula C.; Medeiros, Tayline V.; Benyounes, Anas; Beausoleil, Julien; Menezes, Helvecio C.; Cardeal, Zenilda L.; Lago, Rochel M.; Serp, Philippe

    2014-11-01

    In this work, unique amphiphilic magnetic hybrid carbon nanotubes (CNTs) are synthesized and used as tensioactive nanostructures in different applications. These CNTs interact very well with aqueous media due to the hydrophilic N-doped section, whereas the undoped hydrophobic one has strong affinity for organic molecules. The amphiphilic character combined with the magnetic properties of these CNTs opens the door to completely new and exciting applications in adsorption science and catalysis. These amphiphilic N-doped CNTs can also be used as powerful tensioactive emulsification structures. They can emulsify water/organic mixtures and by a simple magnetic separation the emulsion can be easily broken. We demonstrate the application of these CNTs in the efficient adsorption of various molecules, in addition to promoting biphasic processes in three different reactions, i.e. transesterification of soybean oil, quinoline extractive oxidation with H2O2 and a metal-catalyzed aqueous oxidation of heptanol with molecular oxygen.In this work, unique amphiphilic magnetic hybrid carbon nanotubes (CNTs) are synthesized and used as tensioactive nanostructures in different applications. These CNTs interact very well with aqueous media due to the hydrophilic N-doped section, whereas the undoped hydrophobic one has strong affinity for organic molecules. The amphiphilic character combined with the magnetic properties of these CNTs opens the door to completely new and exciting applications in adsorption science and catalysis. These amphiphilic N-doped CNTs can also be used as powerful tensioactive emulsification structures. They can emulsify water/organic mixtures and by a simple magnetic separation the emulsion can be easily broken. We demonstrate the application of these CNTs in the efficient adsorption of various molecules, in addition to promoting biphasic processes in three different reactions, i.e. transesterification of soybean oil, quinoline extractive oxidation with H2O2 and

  9. Design analysis and performance assessment of hybrid magnetic bearings for a rotary centrifugal blood pump.

    Science.gov (United States)

    Ren, Zhaohui; Jahanmir, Said; Heshmat, Hooshang; Hunsberger, Andrew Z; Walton, James F

    2009-01-01

    A hybrid magnetic bearing system was designed for a rotary centrifugal blood pump being developed to provide long-term circulatory support for heart failure patients. This design consists of two compact bearings to suspend the rotor in five degrees-of-freedom with single axis active control. Permanent magnets are used to provide passive radial support and electromagnets to maintain axial stability of the rotor. Characteristics of the passive radial and active thrust magnetic bearing system were evaluated by the electromagnetic finite element analysis. A proportional-integral-derivative controller with force balance algorithm was implemented for closed loop control of the magnetic thrust bearing. The control position is continuously adjusted based on the electrical energy in the bearing coils, and thus passive magnetic forces carry static thrust loads to minimize the bearing current. Performance of the magnetic bearing system with associated control algorithm was evaluated at different operating conditions. The bearing current was significantly reduced with the force balance control method and the power consumption was below 0.5 W under various thrust loads. The bearing parameters predicted by the analysis were validated by the experimental data.

  10. Hybrid Molecular and Spin Dynamics Simulations for Ensembles of Magnetic Nanoparticles for Magnetoresistive Systems

    Directory of Open Access Journals (Sweden)

    Lisa Teich

    2015-11-01

    Full Text Available The development of magnetoresistive sensors based on magnetic nanoparticles which are immersed in conductive gel matrices requires detailed information about the corresponding magnetoresistive properties in order to obtain optimal sensor sensitivities. Here, crucial parameters are the particle concentration, the viscosity of the gel matrix and the particle structure. Experimentally, it is not possible to obtain detailed information about the magnetic microstructure, i.e., orientations of the magnetic moments of the particles that define the magnetoresistive properties, however, by using numerical simulations one can study the magnetic microstructure theoretically, although this requires performing classical spin dynamics and molecular dynamics simulations simultaneously. Here, we present such an approach which allows us to calculate the orientation and the trajectory of every single magnetic nanoparticle. This enables us to study not only the static magnetic microstructure, but also the dynamics of the structuring process in the gel matrix itself. With our hybrid approach, arbitrary sensor configurations can be investigated and their magnetoresistive properties can be optimized.

  11. Experiments, modeling and simulation of the magnetic behavior of inhomogeneously coated nickel/aluminum hybrid foams

    Energy Technology Data Exchange (ETDEWEB)

    Jung, A., E-mail: anne.jung@mx.uni-saarland.de [Universität des Saarlandes, Institute of Applied Mechanics, Campus A4 2, 66123 Saarbrücken (Germany); Klis, D., E-mail: d.klis@lte.uni-saarland.de [Universität des Saarlandes, Laboratory for Electromagnetic Theory, Campus C6 3, 66123 Saarbrücken (Germany); Goldschmidt, F., E-mail: f.goldschmidt@mx.uni-saarland.de [Universität des Saarlandes, Institute of Applied Mechanics, Campus A4 2, 66123 Saarbrücken (Germany)

    2015-03-15

    Open-cell metal foams are used as lightweight construction elements, energy absorbers or as support for catalytic coatings. Coating of open-cell metal foams is not only used for catalytic applications, but it leads also to tremendous increase in stiffness and energy absorption capacity. A non-line of sight coating technique for complex 3D structures is electrodeposition. Unfortunately, due to the 3D porosity and the related problems in mass transport limitation during the deposition, it is not possible to produce homogeneously coated foams. In the present contribution, we present a semi-non-destructive technique applicable to determine the coating thickness distribution of magnetic coatings by measuring the remanent magnetic field of coated foams. In order to have a closer look at the mass transport mechanism, a numerical model was developed to predict the field scans for different coating thickness distributions in the foams. For long deposition times the deposition reaches a steady state whereas a Helmholtz equation is sufficient to predict the coating thickness distribution. The applied current density could be identified as the main influencing parameter. Based on the developed model, it is possible to improve the electrodeposition process and hence the homogeneity in the coating thickness of coated metal foams. This leads to enhanced mechanical properties of the hybrid foams and contributes to better and resource-efficient energy absorbers and lightweight materials. - Highlights: • Production of hybrid foams by electrodeposition of nickel on open-cell metal foams. • Magnetic field scans for visualization of spatial coating thickness distribution. • Modeling of magnetic fields of inhomogeneously coated hybrid foams. • Investigation of mass transport limitation during coating by a Helmholtz equation. • Increasing coating homogeneity by use of low current densities and deposition rates.

  12. Magnetic field activated lipid-polymer hybrid nanoparticles for stimuli-responsive drug release.

    Science.gov (United States)

    Kong, Seong Deok; Sartor, Marta; Hu, Che-Ming Jack; Zhang, Weizhou; Zhang, Liangfang; Jin, Sungho

    2013-03-01

    Stimuli-responsive nanoparticles (SRNPs) offer the potential of enhancing the therapeutic efficacy and minimizing the side-effects of chemotherapeutics by controllably releasing the encapsulated drug at the target site. Currently controlled drug release through external activation remains a major challenge during the delivery of therapeutic agents. Here we report a lipid-polymer hybrid nanoparticle system containing magnetic beads for stimuli-responsive drug release using a remote radio frequency (RF) magnetic field. These hybrid nanoparticles show long-term stability in terms of particle size and polydispersity index in phosphate-buffered saline (PBS). Controllable loading of camptothecin (CPT) and Fe(3)O(4) in the hybrid nanoparticles was demonstrated. RF-controlled drug release from these nanoparticles was observed. In addition, cellular uptake of the SRNPs into MT2 mouse breast cancer cells was examined. Using CPT as a model anticancer drug the nanoparticles showed a significant reduction in MT2 mouse breast cancer cell growth in vitro in the presence of a remote RF field. The ease of preparation, stability, and controllable drug release are the strengths of the platform and provide the opportunity to improve cancer chemotherapy.

  13. Search for magnetic monopoles with the MoEDAL prototype trapping detector in 8 TeV proton-proton collisions at the LHC

    CERN Document Server

    Acharya, B.

    2016-08-10

    The MoEDAL experiment is designed to search for magnetic monopoles and other highly-ionising particles produced in high-energy collisions at the LHC. The largely passive MoEDAL detector, deployed at Interaction Point 8 on the LHC ring, relies on two dedicated direct detection techniques. The first technique is based on stacks of nuclear-track detectors with surface area $\\sim$18 m$^2$, sensitive to particle ionisation exceeding a high threshold. These detectors are analysed offline by optical scanning microscopes. The second technique is based on the trapping of charged particles in an array of roughly 800 kg of aluminium samples. These samples are monitored offline for the presence of trapped magnetic charge at a remote superconducting magnetometer facility. We present here the results of a search for magnetic monopoles using a 160 kg prototype MoEDAL trapping detector exposed to 8 TeV proton-proton collisions at the LHC, for an integrated luminosity of 0.75 fb$^{-1}$. No magnetic charge exceeding $0.5g_{\\rm...

  14. Search for magnetic monopoles with the MoEDAL prototype trapping detector in 8 TeV proton-proton collisions at the LHC

    CERN Document Server

    CERN. Geneva

    2016-01-01

    The MoEDAL experiment is designed to search for magnetic monopoles and other highly-ionising particles produced in high-energy collisions at the LHC. The largely passive MoEDAL detector, deployed at Interaction Point 8 on the LHC ring, relies on two dedicated direct detection techniques. The first technique is based on stacks of nuclear-track detectors with surface area ∼18 m2, sensitive to particle ionisation exceeding a high threshold. These detectors are analysed offline by optical scanning microscopes. The second technique is based on the trapping of charged particles in an array of roughly 800 kg of aluminium samples. These samples are monitored offline for the presence of trapped magnetic charge at a remote superconducting magnetometer facility. We present here the results of a search for magnetic monopoles using a 160 kg prototype MoEDAL trapping detector exposed to 8 TeV proton-proton collisions at the LHC, for an integrated luminosity of 0.75 fb−1. No magnetic charge exceeding 0.5gD (where gD is ...

  15. Search for magnetic monopoles with the MoEDAL prototype trapping detector in 8 TeV proton-proton collisions at the LHC

    CERN Document Server

    Acharya, B.

    2016-01-01

    The MoEDAL experiment is designed to search for magnetic monopoles and other highly-ionising particles produced in high-energy collisions at the LHC. The largely passive MoEDAL detector, deployed at Interaction Point 8 on the LHC ring, relies on two dedicated direct detection techniques. The first technique is based on stacks of nuclear-track detectors with surface area $\\sim$18 m$^2$, sensitive to particle ionisation exceeding a high threshold. These detectors are analysed offline by optical scanning microscopes. The second technique is based on the trapping of charged particles in an array of roughly 800 kg of aluminium samples. These samples are monitored offline for the presence of trapped magnetic charge at a remote superconducting magnetometer facility. We present here the results of a search for magnetic monopoles using a 160 kg prototype MoEDAL trapping detector exposed to 8 TeV proton-proton collisions at the LHC, for an integrated luminosity of 0.75 fb$^{-1}$. No magnetic charge exceeding $0.5g_{\\rm...

  16. First-order perturbative calculation of the frequency-shifts caused by static cylindrically-symmetric electric and magnetic imperfections of a Penning trap

    CERN Document Server

    Ketter, Jochen; Höcker, Martin; Streubel, Sebastian; Blaum, Klaus

    2014-01-01

    The ideal Penning trap consists of a uniform magnetic field and an electrostatic quadrupole potential. Cylindrically-symmetric deviations thereof are parametrized by the coefficients Bn and Cn, respectively. Relativistic mass-increase aside, the three characteristic eigenfrequencies of a charged particle stored in an ideal Penning trap are independent of the three motional amplitudes. This three-fold harmonicity is a highly-coveted virtue for precision experiments that rely on the measurement of at least one eigenfrequency in order to determine fundamental properties of the stored particle, such as its mass. However, higher-order contributions to the ideal fields result in amplitude-dependent frequency-shifts. In turn, these frequency-shifts need to be understood for estimating systematic experimental errors, and eventually for correcting them by means of calibrating the imperfections. The problem of calculating the frequency-shifts caused by small imperfections of a near-ideal trap yields nicely to perturbat...

  17. Magnetically separable and recyclable Fe3O4-polydopamine hybrid hollow microsphere for highly efficient peroxidase mimetic catalysts.

    Science.gov (United States)

    Liu, Shujun; Fu, Jianwei; Wang, Minghuan; Yan, Ya; Xin, Qianqian; Cai, Lu; Xu, Qun

    2016-05-01

    Magnetic Fe3O4-polydopamine (PDA) hybrid hollow microspheres, in which Fe3O4 nanoparticles were firmly incorporated in the cross-linked PDA shell, have been prepared through the formation of core/shell PS/Fe3O4-PDA composites based on template-induced covalent assembly method, followed by core removal in a tetrahydrofuran solution. The morphology, composition, thermal property and magnetic property of the magnetic hybrid hollow microspheres were characterized by SEM, TEM, FT-IR, XRD, TGA, and vibrating sample magnetometer, respectively. Results revealed that the magnetic hybrid hollow microspheres had about 380 nm of inner diameter and about 30 nm of shell thickness, and 13.6 emu g(-1) of magnetization saturation. More importantly, the Fe3O4-PDA hybrid hollow microspheres exhibited intrinsic peroxidase-like activity, as they could quickly catalyze the oxidation of typical substrates 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide. Compared with PDA/Fe3O4 composites where Fe3O4 nanoparticles were loaded on the surface of PDA microspheres, the stability of Fe3O4-PDA hybrid hollow microspheres was greatly improved. As-prepared magnetic hollow microspheres might open up a new application field in biodetection, biocatalysis, and environmental monitoring. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. The Structure of Hydrated Electron. Part 1. Magnetic Resonance of Internally Trapping Water Anions: A Density Functional Theory Study

    CERN Document Server

    Shkrob, I A

    2006-01-01

    Density functional theory (DFT) is used to rationalize magnetic parameters of hydrated electron trapped in alkaline glasses as observed using Electron Paramagnetic Resonance (EPR) and Electron Spin Echo Envelope Modulation (ESEEM) spectroscopies. To this end, model water cluster anions (n=4-8 and n=20,24) that localize the electron internally are examined. It is shown that EPR parameters of such water anions (such as hyperfine coupling tensors of H/D nuclei in the water molecules) are defined mainly by the cavity size and the coordination number of the electron; the water molecules in the second solvation shell play a relatively minor role. An idealized model of hydrated electron (that is usually attributed to L. Kevan) in which six hydroxyl groups arranged in an octahedral pattern point towards the common center is shown to provide the closest match to the experimental parameters, such as isotropic and anisotropic hyperfine coupling constants for the protons (estimated from ESEEM), the second moment of the E...

  19. Magnetic characterisation of large grain, bulk Y–Ba–Cu–O superconductor–soft ferromagnetic alloy hybrid structures

    OpenAIRE

    Philippe, Matthieu; Fagnard, Jean-François; Kirsch, Sébastien; Xu, Zhihan; Dennis, Anthony; Shi, Yunhua; Cardwell, David A.; Vanderheyden, Benoît; Vanderbemden, Philippe

    2014-01-01

    Large grain, bulk Y–Ba–Cu–O (YBCO) high temperature superconductors (HTS) have significant potential for use in a variety of practical applications that incorporate powerful quasi-permanent magnets. In the present work, we investigate how the trapped field of such magnets can be improved by combining bulk YBCO with a soft FeNi, ferromagnetic alloy. This involves machining the alloy into components of various shapes, such as cylinders and rings, which are attached subsequently to the top surfa...

  20. A hybrid analytical model for open-circuit field calculation of multilayer interior permanent magnet machines

    Science.gov (United States)

    Zhang, Zhen; Xia, Changliang; Yan, Yan; Geng, Qiang; Shi, Tingna

    2017-08-01

    Due to the complicated rotor structure and nonlinear saturation of rotor bridges, it is difficult to build a fast and accurate analytical field calculation model for multilayer interior permanent magnet (IPM) machines. In this paper, a hybrid analytical model suitable for the open-circuit field calculation of multilayer IPM machines is proposed by coupling the magnetic equivalent circuit (MEC) method and the subdomain technique. In the proposed analytical model, the rotor magnetic field is calculated by the MEC method based on the Kirchhoff's law, while the field in the stator slot, slot opening and air-gap is calculated by subdomain technique based on the Maxwell's equation. To solve the whole field distribution of the multilayer IPM machines, the coupled boundary conditions on the rotor surface are deduced for the coupling of the rotor MEC and the analytical field distribution of the stator slot, slot opening and air-gap. The hybrid analytical model can be used to calculate the open-circuit air-gap field distribution, back electromotive force (EMF) and cogging torque of multilayer IPM machines. Compared with finite element analysis (FEA), it has the advantages of faster modeling, less computation source occupying and shorter time consuming, and meanwhile achieves the approximate accuracy. The analytical model is helpful and applicable for the open-circuit field calculation of multilayer IPM machines with any size and pole/slot number combination.

  1. Stationary magnetic shear reversal during Lower Hybrid experiments in Tore Supra

    Energy Technology Data Exchange (ETDEWEB)

    Litaudon, X.; Arslanbekov, R.; Hoang, G.T.; Joffrin, E.; Kazarian-Vibert, F.; Moreau, D.; Peysson, Y.; Bibet, P. [Association Euratom-CEA, Centre d`Etudes de Cadarache, 13 - Saint-Paul-lez-Durance (France). Dept. de Recherches sur la Fusion Controlee; Ferron, J.; Kupfer, K. [General Atomics, San Diego, CA (United States)] [and others

    1996-01-01

    Stable and stationary states with hollow current density profiles have been achieved with Lower Hybrid Current Drive (LHCD) during Lower Hybrid (LH) wave accessibility experiments. By analysing the bounded propagation domain in phase space which naturally limits the central penetration and absorption of the waves, off-axis LH power deposition has been realized in a reproducible manner. The resulting current density profile modifications have led to a global confinement enhancement attributed to the formation of an internal `transport barrier` in the central reversed shear region where the electron thermal diffusivity is reduced to its neoclassical collisional level. The multiple-pass LH wave propagation in the weak Landau damping and reversed magnetic shear regime is also investigated in the framework of a statistical theory and the experimental validation of this theory is discussed. (author). 37 refs.

  2. A hybrid liquid chromatography-mass spectrometry strategy in a forensic laboratory for opioid, cocaine and amphetamine classes in human urine using a hybrid linear ion trap-triple quadrupole mass spectrometer.

    Science.gov (United States)

    Dowling, Geraldine; Regan, Liam; Tierney, Julie; Nangle, Michael

    2010-10-29

    A rapid method has been developed to analyse morphine, codeine, morphine-3-glucuronide, 6-monoacetylmorphine, cocaine, benzoylegonine, buprenorphine, dihydrocodeine, cocaethylene, 3,4-methylenedioxyamphetamine, ketamine, 3,4-methylenedioxymethamphetamine, pseudoephedrine, lignocaine, benzylpiperazine, methamphetamine, amphetamine, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine and methadone in human urine. Urine samples were diluted with methanol:water (1:1, v/v) and sample aliquots were analysed by hybrid linear ion trap-triple quadrupole mass spectrometry with a runtime of 12.5 min. Multiple reaction monitoring (MRM) as survey scan and an enhanced product ion (EPI) scan as dependent scan were performed in an information-dependent acquisition (IDA) experiment. Finally, drug identification and confirmation was carried out by library search with a developed in-house MS/MS library based on EPI spectra at a collision energy spread of 35±15 in positive mode and MRM ratios. The method was validated in urine, according to the criteria defined in Commission Decision 2002/657/EC. At least two MRM transitions for each substance were monitored in addition to EPI spectra and deuterated analytes were used as internal standards for quantitation. The reporting level was 0.05 μg mL(-1) for the range of analytes tested. The regression coefficients (r(2)) for the calibration curves (0-4 μg mL(-1)) in the study were ≥0.98. The method proved to be simple and time efficient and was implemented as an analytical strategy for the illicit drug monitoring of opioids, cocaines and amphetamines in criminal samples from crime offenders, abusers or victims in the Republic of Ireland. To the best of our knowledge there are no hybrid LC-MS applications using MRM mode and product ion spectra in the linear ion trap mode for opioids, cocaines or amphetamines with validation data in urine.

  3. Comprehensive lipidome analysis by shotgun lipidomics on a hybrid quadrupole-orbitrap-linear ion trap mass spectrometer

    DEFF Research Database (Denmark)

    Almeida, Reinaldo; Pauling, Josch Konstantin; Sokol, Elena

    2015-01-01

    , including its high resolution power unsurpassed by any other contemporary Orbitrap instrumentation, its dynamic quantification range and its efficacy for in-depth structural characterization of molecular lipid species by quadrupole-based higher-energy collisional dissociation (HCD), and ion trap...... of fragmentation analysis demonstrated that combined use of HCD and CID yields complementary fragment ions of molecular lipid species. To support global lipidome analysis, we designed a method, termed MS(ALL), featuring high resolution FTMS analysis for lipid quantification, and FTMS(2) analysis using both HCD...... and CID and ITMS(3) analysis utilizing dual CID for in-depth structural characterization of molecular glycerophospholipid species. The performance of the MS(ALL) method was benchmarked in a comparative analysis of mouse cerebellum and hippocampus. This analysis demonstrated extensive lipidome...

  4. Magnetic loading of graphene-nickel nanoparticle hybrid for electrochemical sensing of carbohydrates.

    Science.gov (United States)

    Qu, Weidong; Zhang, Luyan; Chen, Gang

    2013-04-15

    Graphene-nickel nanoparticle hybrid was prepared by the one-step far infrared-assisted reduction of graphene oxide and nickel (II) ions using hydrazine. It was loaded on the surface of a magnetic electrode for electrochemical sensing. The feasibility and performance of the novel electrode were demonstrated by measuring carbohydrates using cyclic voltammetry and amperometry. It demonstrated that nickel nanoparticles decorated on graphene sheets exhibited higher electrocatalytic activity toward the oxidation of carbohydrates while graphene improved the electron transduction. The synergistic effect significantly enhanced the current response of carbohydrates.

  5. Influence of the lower-hybrid drift instability on magnetic reconnection in asymmetric configurations.

    Science.gov (United States)

    Roytershteyn, V; Daughton, W; Karimabadi, H; Mozer, F S

    2012-05-04

    Using fully kinetic 3D simulations of magnetic reconnection in asymmetric antiparallel configurations, we demonstrate that an electromagnetic lower-hybrid drift instability (LHDI) localized near the X line can substantially modify the reconnection mechanism in the regimes with large asymmetry, a moderate ratio of electron to ion temperature, and low plasma β. However, the mode saturates at a small amplitude in the regimes typical of Earth's magnetopause. In these cases, LHDI-driven turbulence is predominantly localized along the separatrices on the low-β side of the current sheet, in agreement with spacecraft observations.

  6. Planar Integrated Magnetics (PIM) Module in Hybrid Bidirectional DC-DC Converter for Fuel Cell Application

    DEFF Research Database (Denmark)

    Ouyang, Ziwei; Zhang, Zhe; Thomsen, Ole Cornelius

    2011-01-01

    , hereby increasing the power density of converters. In this paper, a new planar integrated magnetics (PIM) module for a phase-shift plus duty cycle controlled hybrid bi-directional dc-dc converter is proposed, which assembles one boost inductor and two transformers into an E-I-E core geometry, reducing...... and theoretical analysis, a lab prototype employing the PIM module is implemented for a fuel cell application with 20~40 V input voltage and 400 V output voltage. Detailed results from the experimental comparisons demonstrate that the PIM module is fully functional and electromagnetically equivalent...

  7. Towards trapped antihydrogen

    Science.gov (United States)

    Jørgensen, L. V.; Andresen, G.; Bertsche, W.; Boston, A.; Bowe, P. D.; Cesar, C. L.; Chapman, S.; Charlton, M.; Fajans, J.; Fujiwara, M. C.; Funakoshi, R.; Gill, D. R.; Hangst, J. S.; Hayano, R. S.; Hydomako, R.; Jenkins, M. J.; Kurchaninov, L.; Madsen, N.; Nolan, P.; Olchanski, K.; Olin, A.; Page, R. D.; Povilus, A.; Robicheaux, F.; Sarid, E.; Silveira, D. M.; Storey, J. W.; Thompson, R. I.; van der Werf, D. P.; Wurtele, J. S.; Yamazaki, Y.; Alpha Collaboration

    2008-02-01

    Substantial progress has been made in the last few years in the nascent field of antihydrogen physics. The next big step forward is expected to be the trapping of the formed antihydrogen atoms using a magnetic multipole trap. ALPHA is a new international project that started to take data in 2006 at CERN's Antiproton Decelerator facility. The primary goal of ALPHA is stable trapping of cold antihydrogen atoms to facilitate measurements of its properties. We discuss the status of the ALPHA project and the prospects for antihydrogen trapping.

  8. Towards trapped antihydrogen

    CERN Document Server

    Jorgensen, L V; Bertsche, W; Boston, A; Bowe, P D; Cesar, C L; Chapman, S; Charlton, M; Fajans, J; Fujiwara, M C; Funakoshi, R; Gill, D R; Hangst, J S; Hayano, R S; Hydomako, R; Jenkins, M J; Kurchaninov, L; Madsen, N; Nolan, P; Olchanski, K; Olin, A; Page, R D; Povilus, A; Robicheaux, F; Sarid, E; Silveira, D M; Storey, J W; Thompson, R I; van der Werf, D P; Wurtele, J S; Yamazaki, Y

    2008-01-01

    Substantial progress has been made in the last few years in the nascent field of antihydrogen physics. The next big step forward is expected to be the trapping of the formed antihydrogen atoms using a magnetic multipole trap. ALPHA is a new international project that started to take data in 2006 at CERN’s Antiproton Decelerator facility. The primary goal of ALPHA is stable trapping of cold antihydrogen atoms to facilitate measurements of its properties. We discuss the status of the ALPHA project and the prospects for antihydrogen trapping.

  9. Search for magnetic monopoles with the MoEDAL forward trapping detector in 13 TeV proton-proton collisions at the LHC

    CERN Document Server

    Acharya, B.; Baines, S.; Benes, P.; Bergmann, B.; Bernabéu, J.; Branzas, H.; Campbell, M.; Caramete, L.; Cecchini, S.; de Montigny, M.; De Roeck, A.; Ellis, J.R.; Fairbairn, M.; Felea, D.; Flores, J.; Frank, M.; Frekers, D.; Garcia, C.; Hirt, A.M.; Janecek, J.; Kalliokoski, M.; Katre, A.; Kim, D.-W.; Kinoshita, K.; Korzenev, A.; Lacarrère, D.H.; Lee, S.C.; Leroy, C.; Lionti, A.; Mamuzic, J.; Margiotta, A.; Mauri, N.; Mavromatos, N.E.; Mermod, P.; Mitsou, V.A.; Orava, R.; Parker, B.; Pasqualini, L.; Patrizii, L.; Păvălaş, G.E.; Pinfold, J.L.; Popa, V.; Pozzato, M.; Pospisil, S.; Rajantie, A.; Ruiz de Austri, R.; Sahnoun, Z.; Sakellariadou, M.; Sarkar, S.; Semenoff, G.; Shaa, A.; Sirri, G.; Sliwa, K.; Soluk, R.; Spurio, M.; Srivastava, Y.N.; Suk, M.; Swain, J.; Tenti, M.; Togo, V.; Tuszyński, J.A.; Vento, V.; Vives, O.; Vykydal, Z.; Whyntie, T.; Widom, A.; Willems, G.; Yoon, J.H.; Zgura, I.S.

    2017-02-10

    MoEDAL is designed to identify new physics in the form of long-lived highly-ionising particles produced in high-energy LHC collisions. Its arrays of plastic nuclear-track detectors and aluminium trapping volumes provide two independent passive detection techniques. We present here the results of a search for magnetic monopole production in 13 TeV proton-proton collisions using the trapping technique, extending a previous publication with 8~TeV data during LHC run-1. A total of 222~kg of MoEDAL trapping detector samples were exposed in the forward region and analysed by searching for induced persistent currents after passage through a superconducting magnetometer. Magnetic charges exceeding half the Dirac charge are excluded in all samples and limits are placed for the first time on the production of magnetic monopoles in 13 TeV collisions. The search probes mass ranges previously inaccessible to collider experiments for up to five times the Dirac charge.

  10. Search for Magnetic Monopoles with the MoEDAL Forward Trapping Detector in 13 TeV Proton-Proton Collisions at the LHC

    Science.gov (United States)

    Acharya, B.; Alexandre, J.; Baines, S.; Benes, P.; Bergmann, B.; Bernabéu, J.; Branzas, H.; Campbell, M.; Caramete, L.; Cecchini, S.; de Montigny, M.; De Roeck, A.; Ellis, J. R.; Fairbairn, M.; Felea, D.; Flores, J.; Frank, M.; Frekers, D.; Garcia, C.; Hirt, A. M.; Janecek, J.; Kalliokoski, M.; Katre, A.; Kim, D.-W.; Kinoshita, K.; Korzenev, A.; Lacarrère, D. H.; Lee, S. C.; Leroy, C.; Lionti, A.; Mamuzic, J.; Margiotta, A.; Mauri, N.; Mavromatos, N. E.; Mermod, P.; Mitsou, V. A.; Orava, R.; Parker, B.; Pasqualini, L.; Patrizii, L.; Pǎvǎlaş, G. E.; Pinfold, J. L.; Popa, V.; Pozzato, M.; Pospisil, S.; Rajantie, A.; Ruiz de Austri, R.; Sahnoun, Z.; Sakellariadou, M.; Sarkar, S.; Semenoff, G.; Shaa, A.; Sirri, G.; Sliwa, K.; Soluk, R.; Spurio, M.; Srivastava, Y. N.; Suk, M.; Swain, J.; Tenti, M.; Togo, V.; Tuszyński, J. A.; Vento, V.; Vives, O.; Vykydal, Z.; Whyntie, T.; Widom, A.; Willems, G.; Yoon, J. H.; Zgura, I. S.; MoEDAL Collaboration

    2017-02-01

    MoEDAL is designed to identify new physics in the form of long-lived highly ionizing particles produced in high-energy LHC collisions. Its arrays of plastic nuclear-track detectors and aluminium trapping volumes provide two independent passive detection techniques. We present here the results of a first search for magnetic monopole production in 13 TeV proton-proton collisions using the trapping technique, extending a previous publication with 8 TeV data during LHC Run 1. A total of 222 kg of MoEDAL trapping detector samples was exposed in the forward region and analyzed by searching for induced persistent currents after passage through a superconducting magnetometer. Magnetic charges exceeding half the Dirac charge are excluded in all samples and limits are placed for the first time on the production of magnetic monopoles in 13 TeV p p collisions. The search probes mass ranges previously inaccessible to collider experiments for up to five times the Dirac charge.

  11. Search for Magnetic Monopoles with the MoEDAL Forward Trapping Detector in 13 TeV Proton-Proton Collisions at the LHC.

    Science.gov (United States)

    Acharya, B; Alexandre, J; Baines, S; Benes, P; Bergmann, B; Bernabéu, J; Branzas, H; Campbell, M; Caramete, L; Cecchini, S; de Montigny, M; De Roeck, A; Ellis, J R; Fairbairn, M; Felea, D; Flores, J; Frank, M; Frekers, D; Garcia, C; Hirt, A M; Janecek, J; Kalliokoski, M; Katre, A; Kim, D-W; Kinoshita, K; Korzenev, A; Lacarrère, D H; Lee, S C; Leroy, C; Lionti, A; Mamuzic, J; Margiotta, A; Mauri, N; Mavromatos, N E; Mermod, P; Mitsou, V A; Orava, R; Parker, B; Pasqualini, L; Patrizii, L; Păvălaş, G E; Pinfold, J L; Popa, V; Pozzato, M; Pospisil, S; Rajantie, A; Ruiz de Austri, R; Sahnoun, Z; Sakellariadou, M; Sarkar, S; Semenoff, G; Shaa, A; Sirri, G; Sliwa, K; Soluk, R; Spurio, M; Srivastava, Y N; Suk, M; Swain, J; Tenti, M; Togo, V; Tuszyński, J A; Vento, V; Vives, O; Vykydal, Z; Whyntie, T; Widom, A; Willems, G; Yoon, J H; Zgura, I S

    2017-02-10

    MoEDAL is designed to identify new physics in the form of long-lived highly ionizing particles produced in high-energy LHC collisions. Its arrays of plastic nuclear-track detectors and aluminium trapping volumes provide two independent passive detection techniques. We present here the results of a first search for magnetic monopole production in 13 TeV proton-proton collisions using the trapping technique, extending a previous publication with 8 TeV data during LHC Run 1. A total of 222 kg of MoEDAL trapping detector samples was exposed in the forward region and analyzed by searching for induced persistent currents after passage through a superconducting magnetometer. Magnetic charges exceeding half the Dirac charge are excluded in all samples and limits are placed for the first time on the production of magnetic monopoles in 13 TeV pp collisions. The search probes mass ranges previously inaccessible to collider experiments for up to five times the Dirac charge.

  12. Upper-hybrid wave driven Alfvenic turbulence in magnetized dusty plasmas

    CERN Document Server

    Misra, A P

    2010-01-01

    The nonlinear dynamics of coupled electrostatic upper-hybrid (UH) and Alfven waves (AWs) is revisited in a magnetized electron-ion plasma with charged dust impurities. A pair of nonlinear equations [J.Plasma Phys. 73, 3 (2006)] that describe the interaction of UH wave envelopes (including the relativistic electron mass increase) and the density as well as the compressional magnetic field perturbations associated with the AWs is solved numerically to show that many coherent solitary patterns can be excited and saturated due to modulational instability of unstable UH waves. The evolution of these solitary patterns is also shown to appear in the states of spatiotemporal coherence, temporal as well as spatiotemporal chaos due to collision and fusion among the patterns in stochastic motion. Furthermore, these spatiotemporal features are demonstrated by the analysis of wavelet power spectra. It is found that a redistribution of wave energy takes place to higher harmonic modes with small wavelengths which, in turn, ...

  13. Direct observation of high-spin states in manganese dimer and trimer cations by x-ray magnetic circular dichroism spectroscopy in an ion trap

    Energy Technology Data Exchange (ETDEWEB)

    Zamudio-Bayer, V. [Physikalisches Institut, Universität Freiburg, Stefan-Meier-Straße 21, 79104 Freiburg (Germany); Institut für Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Straße 15, 12489 Berlin (Germany); Hirsch, K.; Langenberg, A.; Kossick, M. [Institut für Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Straße 15, 12489 Berlin (Germany); Institut für Optik und Atomare Physik, Technische Universität Berlin, Hardenbergstraße 36, 10623 Berlin (Germany); Ławicki, A.; Lau, J. T., E-mail: tobias.lau@helmholtz-berlin.de [Institut für Methoden und Instrumentierung der Forschung mit Synchrotronstrahlung, Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Albert-Einstein-Straße 15, 12489 Berlin (Germany); Terasaki, A. [Cluster Research Laboratory, Toyota Technological Institute, 717-86 Futamata, Ichikawa, Chiba 272-0001 (Japan); Department of Chemistry, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581 (Japan); Issendorff, B. von [Physikalisches Institut, Universität Freiburg, Stefan-Meier-Straße 21, 79104 Freiburg (Germany)

    2015-06-21

    The electronic structure and magnetic moments of free Mn{sub 2}{sup +} and Mn{sub 3}{sup +} are characterized by 2p x-ray absorption and x-ray magnetic circular dichroism spectroscopy in a cryogenic ion trap that is coupled to a synchrotron radiation beamline. Our results directly show that localized magnetic moments of 5 μ{sub B} are created by 3d{sup 5}({sup 6}S) states at each ionic core, which are coupled ferromagnetically to form molecular high-spin states via indirect exchange that is mediated in both cases by a delocalized valence electron in a singly occupied 4s derived antibonding molecular orbital with an unpaired spin. This leads to total magnetic moments of 11 μ{sub B} for Mn{sub 2}{sup +} and 16 μ{sub B} for Mn{sub 3}{sup +}, with no contribution of orbital angular momentum.

  14. Direct Observation of High-Spin States in Manganese Dimer and Trimer Cations by X-ray Magnetic Circular Dichroism Spectroscopy in an Ion Trap

    CERN Document Server

    Zamudio-Bayer, Vicente; Langenberg, Andreas; Kossick, Martin; Ławicki, Arkadiusz; Terasaki, Akira; von Issendorff, Bernd; Lau, J Tobias

    2015-01-01

    The electronic structure and magnetic moments of free Mn$_2^+$ and Mn$_3^+$ are characterized by $2p$ x-ray absorption and x-ray magnetic circular dichroism spectroscopy in a cryogenic ion trap that is coupled to a synchrotron radiation beamline. Our results show directly that localized magnetic moments of 5 $\\mu_B$ are created by $3d^5 (^6\\mathrm{S})$ states at each ionic core, which are coupled in parallel to form molecular high-spin states via indirect exchange that is mediated in both cases by a delocalized valence electron in a singly-occupied $4s$ derived orbital with an unpaired spin. This leads to total magnetic moments of 11 $\\mu_B$ for Mn$_2^+$ and 16 $\\mu_B$ for Mn$_3^+$, with no contribution of orbital angular momentum.

  15. Scanning a DNA molecule for bound proteins using hybrid magnetic and optical tweezers.

    Directory of Open Access Journals (Sweden)

    Marijn T J van Loenhout

    Full Text Available The functional state of the genome is determined by its interactions with proteins that bind, modify, and move along the DNA. To determine the positions and binding strength of proteins localized on DNA we have developed a combined magnetic and optical tweezers apparatus that allows for both sensitive and label-free detection. A DNA loop, that acts as a scanning probe, is created by looping an optically trapped DNA tether around a DNA molecule that is held with magnetic tweezers. Upon scanning the loop along the λ-DNA molecule, EcoRI proteins were detected with ~17 nm spatial resolution. An offset of 33 ± 5 nm for the detected protein positions was found between back and forwards scans, corresponding to the size of the DNA loop and in agreement with theoretical estimates. At higher applied stretching forces, the scanning loop was able to remove bound proteins from the DNA, showing that the method is in principle also capable of measuring the binding strength of proteins to DNA with a force resolution of 0.1 pN/[Formula: see text]. The use of magnetic tweezers in this assay allows the facile preparation of many single-molecule tethers, which can be scanned one after the other, while it also allows for direct control of the supercoiling state of the DNA molecule, making it uniquely suitable to address the effects of torque on protein-DNA interactions.

  16. Scanning a DNA molecule for bound proteins using hybrid magnetic and optical tweezers.

    Science.gov (United States)

    van Loenhout, Marijn T J; De Vlaminck, Iwijn; Flebus, Benedetta; den Blanken, Johan F; Zweifel, Ludovit P; Hooning, Koen M; Kerssemakers, Jacob W J; Dekker, Cees

    2013-01-01

    The functional state of the genome is determined by its interactions with proteins that bind, modify, and move along the DNA. To determine the positions and binding strength of proteins localized on DNA we have developed a combined magnetic and optical tweezers apparatus that allows for both sensitive and label-free detection. A DNA loop, that acts as a scanning probe, is created by looping an optically trapped DNA tether around a DNA molecule that is held with magnetic tweezers. Upon scanning the loop along the λ-DNA molecule, EcoRI proteins were detected with ~17 nm spatial resolution. An offset of 33 ± 5 nm for the detected protein positions was found between back and forwards scans, corresponding to the size of the DNA loop and in agreement with theoretical estimates. At higher applied stretching forces, the scanning loop was able to remove bound proteins from the DNA, showing that the method is in principle also capable of measuring the binding strength of proteins to DNA with a force resolution of 0.1 pN/[Formula: see text]. The use of magnetic tweezers in this assay allows the facile preparation of many single-molecule tethers, which can be scanned one after the other, while it also allows for direct control of the supercoiling state of the DNA molecule, making it uniquely suitable to address the effects of torque on protein-DNA interactions.

  17. Comprehensive profiling of N-acylhomoserine lactones produced by Yersinia pseudotuberculosis using liquid chromatography coupled to hybrid quadrupole-linear ion trap mass spectrometry.

    Science.gov (United States)

    Ortori, Catharine A; Atkinson, Steve; Chhabra, Siri Ram; Cámara, Miguel; Williams, Paul; Barrett, David A

    2007-01-01

    A method for the comprehensive profiling of the N-acylhomoserine lactone (AHL) family of bacterial quorum-sensing molecules is presented using liquid chromatography (LC) coupled to hybrid quadrupole-linear ion trap (QqQLIT) mass spectrometry. Information-dependent acquisition (IDA), using triggered combinations of triple-quadrupole and linear ion trap modes in the same LC-MS/MS run, was used to simultaneously screen, quantify and identify multiple AHLs in a single sample. This MS method uses common AHL fragment ions attributed to the homoserine moiety and the 3-oxo-, 3-hydroxy- or unsubstituted acyl side chains, to identify unknown AHLs in cell-free culture supernatants in an unbiased manner. This LC-MS technique was applied to determine the relative molar ratios of AHLs produced by Yersinia pseudotuberculosis and the consequences of inactivating by mutation either or both of the AHL synthase genes (ypsI and ytbI) on AHL profile and concentration. The Y. pseudotuberculosis wild type but not the ypsI ytbI double mutant produced at least 24 different AHLs with acyl chains ranging from C4 to C15 with or without 3-oxo or 3-hydroxy substituents. YtbI, in contrast to YpsI, could direct the synthesis of all of the AHLs identified. The most abundant and hence most biologically relevant Y. pseudotuberculosis AHLs were found to be the 3-oxo-substituted C6, C7 and C8 AHLs and the unsubstituted C6 and C8 compounds. The LC-QqQLIT methodology is broadly applicable to quorum-sensing signal molecule analysis and can provide comprehensive AHL profiles and concentrations from a single sample and simultaneously collect confirmatory spectra for each AHL identified.

  18. Feedforward-feedback hybrid control for magnetic shape memory alloy actuators based on the Krasnosel'skii-Pokrovskii model.

    Directory of Open Access Journals (Sweden)

    Miaolei Zhou

    Full Text Available As a new type of smart material, magnetic shape memory alloy has the advantages of a fast response frequency and outstanding strain capability in the field of microdrive and microposition actuators. The hysteresis nonlinearity in magnetic shape memory alloy actuators, however, limits system performance and further application. Here we propose a feedforward-feedback hybrid control method to improve control precision and mitigate the effects of the hysteresis nonlinearity of magnetic shape memory alloy actuators. First, hysteresis nonlinearity compensation for the magnetic shape memory alloy actuator is implemented by establishing a feedforward controller which is an inverse hysteresis model based on Krasnosel'skii-Pokrovskii operator. Secondly, the paper employs the classical Proportion Integration Differentiation feedback control with feedforward control to comprise the hybrid control system, and for further enhancing the adaptive performance of the system and improving the control accuracy, the Radial Basis Function neural network self-tuning Proportion Integration Differentiation feedback control replaces the classical Proportion Integration Differentiation feedback control. Utilizing self-learning ability of the Radial Basis Function neural network obtains Jacobian information of magnetic shape memory alloy actuator for the on-line adjustment of parameters in Proportion Integration Differentiation controller. Finally, simulation results show that the hybrid control method proposed in this paper can greatly improve the control precision of magnetic shape memory alloy actuator and the maximum tracking error is reduced from 1.1% in the open-loop system to 0.43% in the hybrid control system.

  19. Feedforward-feedback hybrid control for magnetic shape memory alloy actuators based on the Krasnosel'skii-Pokrovskii model.

    Science.gov (United States)

    Zhou, Miaolei; Zhang, Qi; Wang, Jingyuan

    2014-01-01

    As a new type of smart material, magnetic shape memory alloy has the advantages of a fast response frequency and outstanding strain capability in the field of microdrive and microposition actuators. The hysteresis nonlinearity in magnetic shape memory alloy actuators, however, limits system performance and further application. Here we propose a feedforward-feedback hybrid control method to improve control precision and mitigate the effects of the hysteresis nonlinearity of magnetic shape memory alloy actuators. First, hysteresis nonlinearity compensation for the magnetic shape memory alloy actuator is implemented by establishing a feedforward controller which is an inverse hysteresis model based on Krasnosel'skii-Pokrovskii operator. Secondly, the paper employs the classical Proportion Integration Differentiation feedback control with feedforward control to comprise the hybrid control system, and for further enhancing the adaptive performance of the system and improving the control accuracy, the Radial Basis Function neural network self-tuning Proportion Integration Differentiation feedback control replaces the classical Proportion Integration Differentiation feedback control. Utilizing self-learning ability of the Radial Basis Function neural network obtains Jacobian information of magnetic shape memory alloy actuator for the on-line adjustment of parameters in Proportion Integration Differentiation controller. Finally, simulation results show that the hybrid control method proposed in this paper can greatly improve the control precision of magnetic shape memory alloy actuator and the maximum tracking error is reduced from 1.1% in the open-loop system to 0.43% in the hybrid control system.

  20. Magnetic mesoporous organic-inorganic NiCo2O4 hybrid nanomaterials for electrochemical immunosensors.

    Science.gov (United States)

    Li, Qunfang; Zeng, Lingxing; Wang, Jinchao; Tang, Dianping; Liu, Bingqian; Chen, Guonan; Wei, Mingdeng

    2011-04-01

    This study demonstrates a facile and feasible strategy toward the development of advanced electrochemical immunosensors based on chemically functionalized magnetic mesoporous organic-inorganic hybrid nanomaterials, and the preparation, characterization, and measurement of relevant properties of the immunosensor for detection of carcinoembryonic antigen (CEA, as a model analyte) in clinical immunoassays. The as-prepared nanomaterials composed of a magnetic mesoporous NiCo(2)O(4) nanosheet, an interlayer of Nafion/thionine organic molecules and a nanogold layer show good adsorption properties for the attachment of horseradish peroxidase-labeled secondary anti-CEA antibody (HRP-anti-CEA). With a sandwich-type immunoassay format, the functional bionanomaterials present good analytical properties to facilitate and modulate the way it was integrated onto the electrochemical immunosensors, and allows the detection of CEA at a concentration as low as 0.5 pg/mL. Significantly, the immunosensor could be easily regenerated by only using an external magnet without the need of any dissociated reagents. Importantly, the as-synthesized magnetic mesoporous NiCo(2)O(4) nanomaterials could be further extended for detection of other biomarkers or biocompounds.

  1. Higgs mass and muon anomalous magnetic moment in the MSSM with gauge-gravity hybrid mediation

    Science.gov (United States)

    Zhu, Bin; Ding, Ran; Li, Tianjun

    2017-08-01

    In general, we can propose the hybrid supersymmetry breakings and hybrid mediations in the supersymmetric standard models. In this paper, we study the hybrid mediation for supersymmetry (SUSY) breaking. In particular, we study how to keep the good properties of gravity mediation, gauge mediation, and anomaly mediation, while solving their problems simultaneously. As an example, we consider the gauge-gravity mediation, where all the supersymmetric particles (sparticles) obtain the SUSY breaking soft terms from the traditional gravity mediation while gauge mediation gives dominant contributions to the soft terms in the colored sector due to the splitted messengers. Thus, we can realize the electroweak supersymmetry naturally where the sleptons, sneutrinos, and electroweakinos are light within one TeV while the squarks and gluino are heavy around a few TeVs. Then we can explain 125 GeV Higgs mass, satisfy the LHC SUSY search bounds, and explain the anomalous magnetic moment of muon, etc. Moreover, the gluino and squarks are well beyond the current LHC run II searches.

  2. Unidirectional Spin-Dependent Molecule-Ferromagnet Hybridized States Anisotropy in Cobalt Phthalocyanine Based Magnetic Tunnel Junctions

    Science.gov (United States)

    Barraud, Clément; Bouzehouane, Karim; Deranlot, Cyrile; Fusil, Stéphane; Jabbar, Hashim; Arabski, Jacek; Rakshit, Rajib; Kim, Dong-Jik; Kieber, Christophe; Boukari, Samy; Bowen, Martin; Beaurepaire, Eric; Seneor, Pierre; Mattana, Richard; Petroff, Frédéric

    2015-05-01

    Organic or molecular spintronics is a rising field of research at the frontier between condensed matter physics and chemistry. It aims to mix spin physics and the richness of chemistry towards designing new properties for spin electronics devices through engineering at the molecular scale. Beyond the expectation of a long spin lifetime, molecules can be also used to tailor the spin polarization of the injected current through the spin-dependent hybridization between molecules and ferromagnetic electrodes. In this Letter, we provide direct evidence of a hybrid interface spin polarization reversal due to the differing hybridization between phthalocyanine molecules and each cobalt electrode in Co /CoPc /Co magnetic tunnel junctions. Tunnel magnetoresistance and anisotropic tunnel magnetoresistance experiments show that interfacial hybridized electronic states have a unidirectional anisotropy that can be controlled by an electric field and that spin hybridization at the bottom and top interfaces differ, leading to an inverse tunnel magnetoresistance.

  3. A Novel Hybrid-Flux Magnetic Gear and Its Performance Analysis Using the 3-D Finite Element Method

    Directory of Open Access Journals (Sweden)

    Yiduan Chen

    2015-04-01

    Full Text Available This paper presents a novel hybrid-flux magnetic gear, which integrates a transverse-flux magnetic gear and an axial-flux magnetic gear into a single unit. Compared to its conventional counterparts, the proposed magnetic gear transmits a relatively high torque density. When compared to the transverse-flux magnetic gear, this new structure employs an extra iron segment between the low-speed rotor and high-speed rotor to modulate the magnetic field and contribute to the transmission of additional torque. A three-dimensional (3-D finite element method (FEM is used for the analysis of the magnetic field. In the paper a variables-decoupling method based on the sensitivity analysis of the design parameters is also presented to accelerate the optimization process of the proposed machine.

  4. Passive temperature compensation in hybrid magnets with application to the Fermilab stacker and recycler ring dipole design

    Energy Technology Data Exchange (ETDEWEB)

    Schlueter, R.D.; Marks, S.; Loper, C.; Halbach, K.

    1995-06-01

    Design theory of hybrid (permanent magnet plus iron) accelerator magnets with application to the proposed permanent magnet recycler and stacker rings at the Fermi National Laboratory is presented. Field stability in such devices requires that changes in the strength of the permanent magnet material with temperature be compensated. Field tuning techniques, including those employing variable capacitance between energized pole and magnet yoke and those employing variable energization of magnet pole pieces, are described. Mechanical configurations capable of achieving temperature compensation passively, including use of expanding liquids/gases and bimetallic springs are outlined. Active configurations, relying on a actuator, in addition to temperature compensation, have the additional benefit of enabling magnet tuning about a nominal operating field level.

  5. Comprehensive lipidome analysis by shotgun lipidomics on a hybrid quadrupole-orbitrap-linear ion trap mass spectrometer.

    Science.gov (United States)

    Almeida, Reinaldo; Pauling, Josch Konstantin; Sokol, Elena; Hannibal-Bach, Hans Kristian; Ejsing, Christer S

    2015-01-01

    Here we report on the application of a novel shotgun lipidomics platform featuring an Orbitrap Fusion mass spectrometer equipped with an automated nanoelectrospray ion source. To assess the performance of the platform for in-depth lipidome analysis, we evaluated various instrument parameters, including its high resolution power unsurpassed by any other contemporary Orbitrap instrumentation, its dynamic quantification range and its efficacy for in-depth structural characterization of molecular lipid species by quadrupole-based higher-energy collisional dissociation (HCD), and ion trap-based resonant-excitation collision-induced dissociation (CID). This evaluation demonstrated that FTMS analysis with a resolution setting of 450,000 allows distinguishing isotopes from different lipid species and features a linear dynamic quantification range of at least four orders of magnitude. Evaluation of fragmentation analysis demonstrated that combined use of HCD and CID yields complementary fragment ions of molecular lipid species. To support global lipidome analysis, we designed a method, termed MS(ALL), featuring high resolution FTMS analysis for lipid quantification, and FTMS(2) analysis using both HCD and CID and ITMS(3) analysis utilizing dual CID for in-depth structural characterization of molecular glycerophospholipid species. The performance of the MS(ALL) method was benchmarked in a comparative analysis of mouse cerebellum and hippocampus. This analysis demonstrated extensive lipidome quantification covering 311 lipid species encompassing 20 lipid classes, and identification of 202 distinct molecular glycerophospholipid species when applying a novel high confidence filtering strategy. The work presented here validates the performance of the Orbitrap Fusion mass spectrometer for in-depth lipidome analysis.

  6. A hybrid magnetic/complementary metal oxide semiconductor three-context memory bit cell for non-volatile circuit design

    Science.gov (United States)

    Jovanović, B.; Brum, R. M.; Torres, L.

    2014-04-01

    After decades of continued scaling to the beat of Moore's law, it now appears that conventional silicon based devices are approaching their physical limits. In today's deep-submicron nodes, a number of short-channel and quantum effects are emerging that affect the manufacturing process, as well as, the functionality of the microelectronic systems-on-chip. Spintronics devices that exploit both the intrinsic spin of the electron and its associated magnetic moment, in addition to its fundamental electronic charge, are promising solutions to circumvent these scaling threats. Being compatible with the CMOS technology, such devices offer a promising synergy of radiation immunity, infinite endurance, non-volatility, increased density, etc. In this paper, we present a hybrid (magnetic/CMOS) cell that is able to store and process data both electrically and magnetically. The cell is based on perpendicular spin-transfer torque magnetic tunnel junctions (STT-MTJs) and is suitable for use in magnetic random access memories and reprogrammable computing (non-volatile registers, processor cache memories, magnetic field-programmable gate arrays, etc). To demonstrate the potential our hybrid cell, we physically implemented a small hybrid memory block using 45 nm × 45 nm round MTJs for the magnetic part and 28 nm fully depleted silicon on insulator (FD-SOI) technology for the CMOS part. We also report the cells measured performances in terms of area, robustness, read/write speed and energy consumption.

  7. Magnetic-responsive hybrids of Fe3O4 nanoparticles with β-lactoglobulin amyloid fibrils and nanoclusters.

    Science.gov (United States)

    Bolisetty, Sreenath; Vallooran, Jijo J; Adamcik, Jozef; Mezzenga, Raffaele

    2013-07-23

    We report on the synthesis and magnetic-responsive behavior of hybrids formed by dispersing negatively charged iron oxide (Fe3O4) magnetic nanoparticles in positively charged β-lactoglobulin protein solutions at acidic pH, followed by heating at high temperatures. Depending on the pH used, different hybrid aggregates can be obtained, such as nanoparticle-modified amyloid fibrils (pH 3) and spherical nanoclusters (pH 4.5). We investigate the effect of magnetic fields of varying strengths (0-5 T) on the alignment of these Fe3O4-modified amyloid fibrils and spherical nanoclusters using a combination of scattering, birefringence and microscopic techniques and we find a strong alignment of the hybrids upon increasing the intensity of the magnetic field, which we quantify via 2D and 3D order parameters. We also demonstrate the possibility of controlling magnetically the sol-gel behavior of these hybrids: addition of salt (NaCl, 150 mM) to a solution containing nanoparticles modified with β-lactoglobulin amyloid fibrils (2 wt % fibrils modified with 0.6 wt % Fe3O4 nanoparticles) induces first the formation of a reversible gel, which can then be converted back to solution upon application of a moderate magnetic field of 1.1 T. These hybrids offer a new appealing functional colloidal system in which the aggregation, orientational order and rheological behavior can be efficiently controlled in a purely noninvasive way by external magnetic fields of weak intensity.

  8. Presentation and Performance Evaluation of a Novel Stator-Permanent-Magnet Hybrid Stepping Motor

    Directory of Open Access Journals (Sweden)

    Binglin Lu

    2017-05-01

    Full Text Available In this paper, a new type of hybrid stepping motor (HSM with permanent magnets (PMs embedded in the stator, namely the stator-permanent-magnet hybrid stepping motor (SHSM, is presented. It has the same operation principles as the traditional HSM, with a 2-D distributed magnetic field nature and superiorities such as simpler rotor structure, easier PM cooling, higher torque and power density, and higher power grade. Its structural topology and operation principles are initially presented. Then an investigation on the performance comparison between the HSM and the SHSM, in terms of PM flux density, PM torque, detent torque, positional holding accuracy, stator core saturation issue, PM flux leakage, and PM utilization rate is carried out theoretically to make an assessment of the performance superiorities of the SHSM. A prototype of a 2-phase 8-pole 50-rotor-tooth SHSM is fabricated and experimentally compared with the HSM by using finite element analysis (FEA to verify the motor’s operational feasibility and the theoretical analysis. The FEA and experimental results show that the proposed SHSM has performance advantages such as higher torque density, higher power grade, and higher pull-out torque, holding torque, and torque-speed property, although it has performance defects such as higher torque ripple and relatively lower positional holding accuracy in the open-loop operation than the conventional HSM. Consequently, this novel SHSM is more suitable for electromechanical energy conversion applications rather than positioning mechanisms, especially taking into account the open-loop control advantage.

  9. Ion-neutral chemistry at ultralow energies: Dynamics of reactive collisions between laser-cooled Ca^+ ions and Rb atoms in an ion-atom hybrid trap

    CERN Document Server

    Hall, Felix H J; Hegi, Gregor; Raoult, Maurice; Aymar, Mireille; Dulieu, Olivier; Willitsch, Stefan

    2013-01-01

    Cold chemical reactions between laser-cooled Ca^+ ions and Rb atoms were studied in an ion-atom hybrid trap. Reaction rate constants were determined in the range of collision energies /k_B = 20 mK-20 K. The lowest energies were achieved in experiments using single localized Ca^+ ions. Product branching ratios were studied using resonant-excitation mass spectrometry. The dynamics of the reactive processes in this system (non-radiative and radiative charge transfer as well as radiative association leading to the formation of CaRb^+ molecular ions) have been analyzed using high-level quantum-chemical calculations of the potential energy curves of CaRb^+ and quantum-scattering calculations for the radiative channels. For the present low-energy scattering experiments, it is shown that the energy dependence of the reaction rate constants is governed by long-range interactions in line with the classical Langevin model, but their magnitude is determined by short-range non-adiabatic and radiative couplings which only ...

  10. Absence of long-range order in the frustrated magnet SrDy2O4 due to trapped defects from a dimensionality crossover

    Science.gov (United States)

    Gauthier, N.; Fennell, A.; Prévost, B.; Uldry, A.-C.; Delley, B.; Sibille, R.; Désilets-Benoit, A.; Dabkowska, H. A.; Nilsen, G. J.; Regnault, L.-P.; White, J. S.; Niedermayer, C.; Pomjakushin, V.; Bianchi, A. D.; Kenzelmann, M.

    2017-04-01

    Magnetic frustration and low dimensionality can prevent long-range magnetic order and lead to exotic correlated ground states. SrDy2O4 consists of magnetic Dy3 + ions forming magnetically frustrated zigzag chains along the c axis and shows no long-range order to temperatures as low as T =60 mK. We carried out neutron scattering and ac magnetic susceptibility measurements using powder and single crystals of SrDy2O4 . Diffuse neutron scattering indicates strong one-dimensional (1D) magnetic correlations along the chain direction that can be qualitatively accounted for by the axial next-nearest-neighbor Ising model with nearest-neighbor and next-nearest-neighbor exchange J1=0.3 meV and J2=0.2 meV, respectively. Three-dimensional (3D) correlations become important below T*≈0.7 K. At T =60 mK, the short-range correlations are characterized by a putative propagation vector k1 /2=(0 ,1/2 ,1/2 ) . We argue that the absence of long-range order arises from the presence of slowly decaying 1D domain walls that are trapped due to 3D correlations. This stabilizes a low-temperature phase without long-range magnetic order, but with well-ordered chain segments separated by slowly moving domain walls.

  11. Magnetism in Sc-doped ZnO with zinc vacancies: A hybrid density functional and GGA + U approaches

    KAUST Repository

    Kanoun, Mohammed

    2012-04-01

    We investigate the zinc vacancy effects on the electronic structures and magnetic properties of Sc-doped ZnO, by performing first-principles calculations within both GGA + U and Heyd-Scuseria-Ernzerhof hybrid functional methods. We find that Sc impurities stabilize considerably Zn vacancies. The electronic and magnetic analysis shows a half metallic ferromagnetic character with a total magnetic moment of 2.01 μ B. The magnetism mainly stems from the O 2p states around the Zn vacancies. Calculations with the hybrid density functional agree with the GGA + U results but give an accurate description of the electronic structure for pure ZnO and Sc-doped ZnO with Zn vacancies. © 2012 Elsevier B.V. All rights reserved.

  12. Design,analysis and control of hybrid excited doubly salient stator-permanent-magnet motor

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In this paper,a new hybrid excited doubly salient stator-permanent-magnet motor is proposed,where both permanent magnets and DC field windings are located in the stator.In theory,the mathematical model and design method of the motor are developed.The corresponding output power equation and the relationship between the flux control capability and the extended speed range are deduced in details.By using an efficient "one-step" three-dimensional(3D) finite element method,the electromagnetic performances are analyzed,in which the leakage flux outside the stator circumference and end-effect are taken into account.Based on the operation principle of the motor,the control strategy and scheme are developed and implemented experimentally.Both experimental results and finite element analysis show that the proposed motor not only maintains the advantages of doubly salient permanent magnet motors,but also offers high energy efficiency over a wide speed range,which makes the motor an interesting candidate for electric vehicles.

  13. Discrimination of clostridium species using a magnetic bead based hybridization assay

    Science.gov (United States)

    Pahlow, Susanne; Seise, Barbara; Pollok, Sibyll; Seyboldt, Christian; Weber, Karina; Popp, Jürgen

    2014-05-01

    Clostridium chauvoei is the causative agent of blackleg, which is an endogenous bacterial infection. Mainly cattle and other ruminants are affected. The symptoms of blackleg are very similar to those of malignant edema, an infection caused by Clostridium septicum. [1, 2] Therefore a reliable differentiation of Clostridium chauvoei from other Clostridium species is required. Traditional microbiological detection methods are time consuming and laborious. Additionally, the unique identification is hindered by the overgrowing tendency of swarming Clostridium septicum colonies when both species are present. [1, 3, 4] Thus, there is a crucial need to improve and simplify the specific detection of Clostridium chauvoei and Clostridium septicum. Here we present an easy and fast Clostridium species discrimination method combining magnetic beads and fluorescence spectroscopy. Functionalized magnetic particles exhibit plentiful advantages, like their simple manipulation in combination with a large binding capacity of biomolecules. A specific region of the pathogenic DNA is amplified and labelled with biotin by polymerase chain reaction (PCR). These PCR products were then immobilized on magnetic beads exploiting the strong biotin-streptavidin interaction. The specific detection of different Clostridium species is achieved by using fluorescence dye labeled probe DNA for the hybridization with the immobilized PCR products. Finally, the samples were investigated by fluorescence spectroscopy. [5

  14. A novel integrated 4-DOF radial hybrid magnetic bearing for MSCMG

    Science.gov (United States)

    Jinji, Sun; Ziyan, Ju; Weitao, Han; Gang, Liu

    2017-01-01

    This paper proposes a novel integrated radial hybrid magnetic bearing (RHMB) for application with the small-sized magnetically suspended control moment gyroscope (MSCMG), which can control four degrees of freedom (4-DOFs), including two radial translational DOFs and two radial tilting DOFs, and provide the axial passive resilience. The configuration and working principle of the RHMB are introduced. Mathematical models of radial force, axial resilience and moment are established by using equivalent magnetic circuit method (EMCM), from which the radial force-radial displacement, radial force-current relationships are derived, as well as axial resilience-axial displacement, moment-tilting angle and moment-current. Finite element method (FEM) is also applied to analyze the performance and characteristics of the RHMB. The analysis results are in good agreement with that calculated by the EMCM, which is helpful in designing, optimizing and controlling the RHMB. The comparisons between the performances of the integrated 4-DOF RHMB and the traditional 4-DOF RHMB are made. The contrast results indicate that the proposed integrated 4-DOF RHMB possesses better performance compared to the traditional structure, such as copper loss, current stiffness, and tilting current stiffness.

  15. Studies of a hybrid avalanche photo-detector in magnetic field

    Science.gov (United States)

    Šantelj, L.; Adachi, I.; Hataya, K.; Iori, S.; Iwata, S.; Kakuno, H.; Kataura, R.; Kawai, H.; Kindo, H.; Korpar, S.; Križan, P.; Mrvar, M.; Nath, K.; Nishida, S.; Ogawa, S.; Pestotnik, R.; Stanovnik, A.; Seljak, A.; Sumiyoshi, T.; Tabata, M.; Tahirovič, E.; Yusa, Y.

    2017-02-01

    For the Belle II spectrometer a proximity focusing RICH counter with an aerogel radiator (ARICH) will be employed as a PID system in the forward endcap region of the spectrometer. The main challenge was the development of a reliable multichannel sensor for single photons that operates in the high magnetic field of the spectrometer (1.5 T) and withstands the radiation levels expected at the experiment. A 144-channel Hybrid Avalanche Photo-Detector (HAPD) was developed with Hamamatsu Photonics K.K. and the mass production of ∼480 HAPDs was completed recently. While our first tests of HAPD performance in the magnetic field (before mass production) showed no issues, we lately observed a presence of very large signal pulses (∼5000× single photon signal), generated internally within about 20% of HAPDs, while operating in the magnetic field. The rate of these pulses varies from sample to sample. These pulses impact the HAPD performance in two ways: they introduce periods of dead time and, in some cases, damage to the front-end electronics was observed. Here we present conditions under which such large pulses are generated, their properties and impact on HAPD performance, and discuss possible mechanism of their origin.

  16. Hybrid Adaptive Filter development for the minimisation of transient fluctuations superimposed on electrotelluric field recordings mainly by magnetic storms

    Directory of Open Access Journals (Sweden)

    A. Konstantaras

    2006-01-01

    Full Text Available The method of Hybrid Adaptive Filtering (HAF aims to recover the recorded electric field signals from anomalies of magnetotelluric origin induced mainly by magnetic storms. An adaptive filter incorporating neuro-fuzzy technology has been developed to remove any significant distortions from the equivalent magnetic field signal, as retrieved from the original electric field signal by reversing the magnetotelluric method. Testing with further unseen data verifies the reliability of the model and demonstrates the effectiveness of the HAF method.

  17. Hybrid Integration of Magnetoresistive Sensors with MEMS as a Strategy to Detect Ultra-Low Magnetic Fields

    Directory of Open Access Journals (Sweden)

    João Valadeiro

    2016-05-01

    Full Text Available In this paper, we describe how magnetoresistive sensors can be integrated with microelectromechanical systems (MEMS devices enabling the mechanical modulation of DC or low frequency external magnetic fields to high frequencies using MEMS structures incorporating magnetic flux guides. In such a hybrid architecture, lower detectivities are expected when compared with those obtained for individual sensors. This particularity results from the change of sensor’s operating point to frequencies above the 1/f noise knee.

  18. Electron--electron double resonance study of magnetic energy transfer between trapped electrons and radicals in organic glasses: Relation between dipolar cross relaxation times and dipolar interaction distances

    Energy Technology Data Exchange (ETDEWEB)

    Lin, D.P.; Feng, D.F.; Ngo, F.Q.H.; Kevan, L.

    1976-11-15

    Electron--electron double resonance (ELDOR) has been used to measure cross-relaxation times between trapped electrons and trapped radicals produced by ..gamma.. irradiation of 2-methyltetrahydrofuran and 3-methylhexane organic glasses. The cross-relaxation times are measured as a function of temperature, radiation dose, and the frequency difference ..delta..f of the microwave frequencies used. The cross-relaxation times are nearly temperature independent and depend on ..delta..f/sup 2/ at doses where the spin concentrations approach uniformity; these features indicate the dominance of single step over multistep cross-relaxation processes. Equations have been derived to relate the dipolar cross-relaxation distance to the measured cross-relaxation times, and it is suggested that the cross-relaxation line shape is Lorentzian in magnetically dilute systems. Typical electron--radical correlation distances in these organic glasses are 10 A. (AIP)

  19. Zeeman spectrum and magnetic effect of trapped 199Hg+ ions%囚禁汞(199Hg+)离子Zeeman谱及磁场效应

    Institute of Scientific and Technical Information of China (English)

    黄雄; 杨玉娜; 柳浩; 高克林; 佘磊; 李交美

    2011-01-01

    The experiment of optical-microwave double-resonance in trapped mercury is the basis for the research of mercury ion microwave frequency standard.The second-order Zeeman effect is one of the important factor affecting frequency stability and the magnetic field effect.The Zeeman spectrum of ground state of trapped 199Hg+ ion was measured by the method of optical-microwave double-resonance.The clock transition frequency and linewidth of the clock transition line were obtained by scanning the microwave frequency in a narrow region.The magnetic field in trapping area was shielded by the materials of permalloy.The linewidth of the clock transition line is decreased to about 1.5 Hz.Comparing the clock transition frequency without magnetic shielding, the clock transition frequency of magnetic shielding decreases 13.5 Hz.According to the second-order Zeeman effect, it's calculated that the magnetic field of trapped region is about 0.1 Guass.%囚禁汞离子的光微波双共振实验是开展汞离子微波频标的实验基础.二级Zeeman效应是影响频率稳定度和磁场效应的重要因素之一.利用光学微波双共振方法测量了囚禁199Hg+离子基态Zeeman分裂.通过减小微波扫描的频率范围,得到钟跃迁频率和谱线线宽.采用磁屏蔽材料(坡莫合金)对离子阱囚禁区域的磁场进行屏蔽.使得囚禁汞离子的钟跃迁谱线的线宽减小到1.5 Hz.相对于无磁场屏蔽时,钟跃迁频率减小13.5 Hz,并利用二级Zeeman效应估算出磁屏蔽后离子囚禁区域磁场大小为0.1高斯.

  20. Trapping of ultra cold atoms in a 3He/4He dilution refrigerator

    CERN Document Server

    Jessen, F; Bell, S C; Vergien, P; Hattermann, H; Weiss, P; Rudolph, M; Reinschmidt, M; Meyer, K; Gaber, T; Cano, D; Guenther, A; Bernon, S; Koelle, D; Kleiner, R; Fortagh, J

    2013-01-01

    We describe the preparation of ultra cold atomic clouds in a dilution refrigerator. The closed cycle 3He/4He cryostat was custom made to provide optical access for laser cooling, optical manipulation and detection of atoms. We show that the cryostat meets the requirements for cold atom experiments, specifically in terms of operating a magneto-optical trap, magnetic traps and magnetic transport under ultra high vacuum conditions. The presented system is a step towards the creation of a quantum hybrid system combining ultra cold atoms and solid state quantum devices.

  1. Progress in the manufacture of the cable-in-conduit Nb{sub 3}Sn outsert coils for the 45 Tesla Hybrid Magnet

    Energy Technology Data Exchange (ETDEWEB)

    Painter, T.A.; Miller, J.R.; Summers, L.T. [Florida State Univ., Tallahassee, FL (United States). National High Magnetic Field Lab.] [and others

    1994-07-01

    The 45 Tesla Hybrid Magnet is being built in a collaborative effort between the National High Magnetic Field Laboratory at Florida State University and the Francis Bitter National Magnet Laboratory at the Massachusetts Institute of Technology. The Hybrid Magnet combines a resistive insert magnet with two Nb3Sn and one NbTi superconducting cable-in-conduit outsert coil to produce the required field on axis. The Nb3Sn outsert coils are being built at Intermagnetics General Corporation under contract with FSU. A design summary for the entire 100 MJ outsert magnet is presented. The design criteria and manufacturing status for the two Nb3Sn outsert coils are described.

  2. Oxygen trapped by rare earth tetrahedral clusters in Nd{sub 4}FeOS{sub 6}: Crystal structure, electronic structure, and magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Qisheng, E-mail: qslin@ameslab.gov [Division of Materials Sciences and Engineering, Ames Laboratory, US-DOE, Ames, IA 50011 (United States); Taufour, Valentin [Division of Materials Sciences and Engineering, Ames Laboratory, US-DOE, Ames, IA 50011 (United States); Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States); Zhang, Yuemei [Department of Chemistry, Iowa State University, Ames, IA 50011 (United States); Wood, Max; Drtina, Thomas; Bud’ko, Sergey L.; Canfield, Paul C. [Division of Materials Sciences and Engineering, Ames Laboratory, US-DOE, Ames, IA 50011 (United States); Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States); Miller, Gordon J. [Division of Materials Sciences and Engineering, Ames Laboratory, US-DOE, Ames, IA 50011 (United States); Department of Chemistry, Iowa State University, Ames, IA 50011 (United States)

    2015-09-15

    Single crystals of Nd{sub 4}FeOS{sub 6} were grown from an Fe–S eutectic solution. Single crystal X-ray diffraction analysis revealed a Nd{sub 4}MnOSe{sub 6}-type structure (P6{sub 3}mc, a=9.2693(1) Å, c=6.6650(1)Å, V=495.94(1) Å{sup 3}, Z=2), featuring parallel chains of face-sharing [FeS{sub 6×1/2}]{sup 4−} trigonal antiprisms and interlinked [Nd{sub 4}OS{sub 3}]{sup 4+} cubane-like clusters. Oxygen atoms were found to be trapped by Nd{sub 4} clusters in the [Nd{sub 4}OS{sub 3}]{sup 4{sub +}} chains. Structural differences among Nd{sub 4}MnOSe{sub 6}-type Nd{sub 4}FeOS{sub 6} and the related La{sub 3}CuSiS{sub 7}− and Pr{sub 8}CoGa{sub 3}-type structures have been described. Magnetic susceptibility measurements on Nd{sub 4}FeOS{sub 6} suggested the dominance of antiferromagnetic interactions at low temperature, but no magnetic ordering down to 2 K was observed. Spin-polarized electronic structure calculations revealed magnetic frustration with dominant antiferromagnetic interactions. - Graphical abstract: Trapping of oxygen in Nd{sub 4} tetrahedral clusters results in the formation of the Nd{sub 4}MnOSe{sub 6}-type Nd{sub 4}FeOS{sub 6}, in contrast to the La{sub 3}CuSiS{sub 7}-type oxygen-free Nd{sub 4}FeS{sub 7} and related Pr{sub 8}CoGa{sub 3}-type structures. Complex magnetic frustration inhibits magnetic ordering at low temperature. - Highlights: • Single crystals of Nd{sub 4}FeOS{sub 6} were grown using self-flux method. • Oxygen was found trapped by Nd{sub 4} tetrahedral clusters. • Comparison with two closely related structural types were discussed. • Magnetic measurements revealed antiferromagnetic (AFM) interaction. • VASP calculations confirmed strong magnetic frustration in AFM model.

  3. Low eddy loss axial hybrid magnetic bearing with gimballing control ability for momentum flywheel

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Jiqiang, E-mail: tjq_72@163.com [School of Instrument Science and Opto-electronics Engineering, Beihang University, Beijing 100191 (China); Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576 (Singapore); Sun, Jinji; Fang, Jiancheng [School of Instrument Science and Opto-electronics Engineering, Beihang University, Beijing 100191 (China); Shuzhi Sam, Ge [Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576 (Singapore)

    2013-03-15

    For a magnetically suspended momentum flywheel (MSMF), the spinning rotor can be tilted by a pair of the presented axial hybrid magnetic bearing (AHMB) with eight poles and rotates around the radial axes to generate a large torque to maneuver the spacecraft. To improve the control performance and gimballing control ability of the AHMB, characteristics such as magnetic suspension force, angular stiffness and tilting momentum are researched. These segmented stator poles cause the magnetic density in the thrust rotor plate to be uneven unavoidably and the rotational loss is large at high speed, but we optimized the stator poles configuration and caused the thrust rotor plate formed by bulk DT4C and laminated material to make the magnetic density in the thrust rotor plate change less and be smoother. Laminated material such as 1J50 film with a thickness of 0.1 mm can make the variation of the magnetic density in DT4C become very small and the eddy loss of it be negligible, but the stress produced in the 'O' shape stacks by reeling has a bad effect on its power loss. Nanocrystalline can reduce eddy losses and is not affected by the reeling process. Based on the AHBM consisting of the stator with eight improved poles and the presented thrust rotor plate with DT4 and nanocrystalline, the rotational loss of 5-DOF magnetically suspended momentum flywheel with angular momentum of 15 N m s at 5000 rpm has reduced from 23.4 W to 3.2 W, which proved that this AHMB has low eddy loss for the gimballing control ability. - Highlights: Black-Right-Pointing-Pointer Control methods of rotor driven by AHMBs and their characteristics are researched. Black-Right-Pointing-Pointer Optimized stator and rotor of AHMB reduce its eddy losses greatly. Black-Right-Pointing-Pointer Presented the factors affecting the eddy losses of AHMBs. Black-Right-Pointing-Pointer The good performances of AHMB with low eddy loss are proved by experiments.

  4. Perpendicular magnetic anisotropy in the Heusler alloy Co2TiSi/GaAs(001 hybrid structure

    Directory of Open Access Journals (Sweden)

    M. T. Dau

    2015-05-01

    Full Text Available Investigation of the thickness dependence of the magnetic anisotropy in B2-type Co2TiSi films on GaAs(001, shows a pronounced perpendicular magnetic anisotropy at 10 K for thicknesses up to 13.5 nm. We have evidenced that the interfacial anisotropy induced by interface clusters has a strong influence on the perpendicular magnetic anisotropy of this hybrid structure, especially at temperatures lower than the blocking temperature of the clusters (28 K. However, as this influence can be ruled out at higher temperatures, the perpendicular magnetic anisotropy which is found to persist up to room-temperature can be ascribed to the magnetic properties of the Co2TiSi films. For thicknesses larger than 15.0 nm, we observe an alignment of the magnetic easy axis parallel to the sample surface, which is most likely due to the shape anisotropy and the film structure.

  5. New Magnetic Thin Film Hybrid Materials Built by the Incorporation of Octanickel(II)-oxamato Clusters Between Clay Mineral Platelets

    NARCIS (Netherlands)

    Toma, Luminita M.; Gengler, Regis Y. N.; Cangussu, Danielle; Pardo, Emilio; Lloret, Francesc; Rudolf, Petra

    2011-01-01

    We report on a new method based on the combination of Langmuir-Schaefer deposition with self-assembly to insert highly anisotropic Ni(8) molecules in a hybrid organic-inorganic nanostructure. Spectroscopic, crystallographic, and magnetic data prove the successful insertion of the guest cationic mole

  6. Whole-body magnetic resonance angiography at 3 tesla using a hybrid protocol in patients with peripheral arterial disease

    DEFF Research Database (Denmark)

    Nielsen, Yousef W; Eiberg, Jonas P; Logager, Vibeke B

    2009-01-01

    The purpose of this study was to determine the diagnostic performance of 3T whole-body magnetic resonance angiography (WB-MRA) using a hybrid protocol in comparison with a standard protocol in patients with peripheral arterial disease (PAD). In 26 consecutive patients with PAD two different proto...

  7. Application of Nuclear Magnetic Resonance and Hybrid Methods to Structure Determination of Complex Systems.

    Science.gov (United States)

    Prischi, Filippo; Pastore, Annalisa

    2016-01-01

    The current main challenge of Structural Biology is to undertake the structure determination of increasingly complex systems in the attempt to better understand their biological function. As systems become more challenging, however, there is an increasing demand for the parallel use of more than one independent technique to allow pushing the frontiers of structure determination and, at the same time, obtaining independent structural validation. The combination of different Structural Biology methods has been named hybrid approaches. The aim of this review is to critically discuss the most recent examples and new developments that have allowed structure determination or experimentally-based modelling of various molecular complexes selecting them among those that combine the use of nuclear magnetic resonance and small angle scattering techniques. We provide a selective but focused account of some of the most exciting recent approaches and discuss their possible further developments.

  8. Using multimedia learning modules in a hybrid-online course in electricity and magnetism

    Science.gov (United States)

    Sadaghiani, Homeyra R.

    2011-06-01

    We have been piloting web-based multimedia learning modules (MLMs), developed by the Physics Education Research Group at the University of Illinois at Urbana Champaign (UIUC), as a “prelecture assignment” in several introductory physics courses at California State Polytechnic University at Pomona. In this study, we report the results from a controlled study utilizing modules on electricity and magnetism as a part of a blended hybrid-online course. We asked students in the experimental section to view the MLMs prior to attending the face-to-face class, and to make sure this would not result in additional instructional time, we reduced the weekly class time by one-third. We found that despite reduced class time, student-learning outcomes were not hindered; in fact, the implementation of the UIUC MLMs resulted in a positive effect on student performance on conceptual tests and classroom discussion questions.

  9. Magnetic composites based on hybrid spheres of aluminum oxide and superparamagnetic nanoparticles of iron oxides

    Energy Technology Data Exchange (ETDEWEB)

    Braga, Tiago P. [Langmuir - Laboratorio de Adsorcao e Catalise, Departamento de Quimica Analitica e Fisico-Quimica, Universidade Federal do Ceara, CP 6021, CEP 60455-970 Campus do Pici, Fortaleza (Brazil); Vasconcelos, Igor F. [Departamento de Engenharia Metalurgica e de Materiais, Universidade Federal do Ceara, Fortaleza (Brazil); Sasaki, Jose M. [Laboratorio de Raios X, Departamento de Fisica, Universidade Federal do Ceara, Campus do Pici, Fortaleza, CE (Brazil); Fabris, J.D.; Oliveira, Diana Q.L. de [Departamento de Quimica, Universidade Federal de Minas Gerais, Belo Horizonte (Brazil); Valentini, Antoninho, E-mail: valent@ufc.b [Langmuir - Laboratorio de Adsorcao e Catalise, Departamento de Quimica Analitica e Fisico-Quimica, Universidade Federal do Ceara, CP 6021, CEP 60455-970 Campus do Pici, Fortaleza (Brazil)

    2010-03-15

    Materials containing hybrid spheres of aluminum oxide and superparamagnetic nanoparticles of iron oxides were obtained from a chemical precursor prepared by admixing chitosan and iron and aluminum hydroxides. The oxides were first characterized with scanning electron microscopy, X-ray diffraction, and Moessbauer spectroscopy. Scanning electron microscopy micrographs showed the size distribution of the resulting spheres to be highly homogeneous. The occurrence of nano-composites containing aluminum oxides and iron oxides was confirmed from powder X-ray diffraction patterns; except for the sample with no aluminum, the superparamagnetic relaxation due to iron oxide particles were observed from Moessbauer spectra obtained at 298 and 110 K; the onset six line-spectrum collected at 20 K indicates a magnetic ordering related to the blocking relaxation effect for significant portion of small spheres in the sample with a molar ratio Al:Fe of 2:1.

  10. Using multimedia learning modules in a hybrid-online course in electricity and magnetism

    Directory of Open Access Journals (Sweden)

    Homeyra R. Sadaghiani

    2011-03-01

    Full Text Available We have been piloting web-based multimedia learning modules (MLMs, developed by the Physics Education Research Group at the University of Illinois at Urbana Champaign (UIUC, as a “prelecture assignment” in several introductory physics courses at California State Polytechnic University at Pomona. In this study, we report the results from a controlled study utilizing modules on electricity and magnetism as a part of a blended hybrid-online course. We asked students in the experimental section to view the MLMs prior to attending the face-to-face class, and to make sure this would not result in additional instructional time, we reduced the weekly class time by one-third. We found that despite reduced class time, student-learning outcomes were not hindered; in fact, the implementation of the UIUC MLMs resulted in a positive effect on student performance on conceptual tests and classroom discussion questions.

  11. General and hybrid correlation nuclear magnetic resonance analysis of phosphorus in Phytophthora palmivora.

    Science.gov (United States)

    Kirwan, Gemma M; Fernandez, David I; Niere, Julie O; Adams, Michael J

    2012-10-01

    Generalized two-dimensional (Gen2D) correlation analysis and hybrid correlation analysis have been applied to a series of dynamic (31)P nuclear magnetic resonance (NMR) spectra to monitor the in vivo metabolic changes of the plant pathogen Phytophthora palmivora in the presence and absence of phosphonate over an 18-h period. Results indicate that phosphonate exposure causes cleavage in organism polyphosphate chains as well as an increase in total sugar phosphates. In the presence of phosphonate, the NMR resonances attributed to terminal polyphosphate phosphorus reduced at a lower rate than those of middle polyphosphate phosphorus, indicating a change in average chain length and suggesting cleavage in the middle of the chain as well as at the ends. The correlation analysis techniques serve to identify and confirm spectral regions undergoing major change in the time-series data and facilitate the analysis of these dynamic changes.

  12. Magnetic silica hybrids modified with guanidine containing co-polymers for drug delivery applications

    Energy Technology Data Exchange (ETDEWEB)

    Timin, Alexander S., E-mail: a_timin@mail.ru [Inorganic Chemistry Department, Ivanovo State University of Chemistry and Technology (ISUCT), 7, Sheremetevsky prosp., 153000 Ivanovo (Russian Federation); RASA Center in Tomsk, Tomsk Polytechnic University, 30, Lenin Avenue, 634500 Tomsk (Russian Federation); Khashirova, Svetlana Yu. [Kabardino-Balkar State University, ul. Chernyshevskogo 173, Nal' chik, 360004 Kabardino-Balkaria (Russian Federation); Rumyantsev, Evgeniy V.; Goncharenko, Alexander A. [Inorganic Chemistry Department, Ivanovo State University of Chemistry and Technology (ISUCT), 7, Sheremetevsky prosp., 153000 Ivanovo (Russian Federation)

    2016-07-01

    Guanidine containing co-polymers grafted onto silica nanoparticles to form core-shell structure were prepared by sol-gel method in the presence of γ-Fe{sub 2}O{sub 3} nanoparticles. The morphological features for uncoated and coated silica particles have been characterized with scanning electron microscopy. The results show that the polymer coated silicas exhibit spherical morphology with rough polymeric surface covered by γ-Fe{sub 2}O{sub 3} nanoparticles. The grafting amount of guanidine containing co-polymers evaluated by thermogravimetric analysis was in the range from 17 to 30%. Then, the drug loading properties and cumulative release of silica hybrids modified with guanidine containing co-polymers were evaluated using molsidomine as a model drug. It was shown that after polymer grafting the loading content of molsidomine could reach up to 3.42 ± 0.21 and 2.34 ± 0.14 mg/g respectively. The maximum drug release of molsidomine is achieved at pH 1.6 (approximately 71–75% release at 37 °C), whereas at pH 7.4 drug release is lower (50.4–59.6% release at 37 °C). These results have an important implication that our magneto-controlled silica hybrids modified with guanidine containing co-polymers are promising as drug carriers with controlled behaviour under influence of magnetic field. - Highlights: • Polymer coated silica hybrids containing γ-Fe{sub 2}O{sub 3} were prepared via sol–gel method. • Polymer grafting influences pH-response and surface properties of final products. • Molsidomine as a model drug was effectively loaded into polymer coated silicas. • The drug loading depends on the nature of grafted polymer and its content.

  13. The Nanocluster Trap endstation at BESSY II

    Directory of Open Access Journals (Sweden)

    Tobias Lau

    2017-05-01

    Full Text Available The Nanocluster Trap endstation at BESSY II combines a cryogenic linear radio-frequency ion trap with an applied magnetic field for x-ray magnetic circular dichroism studies of cold and size-selected trapped ions. Applications include atomic, molecular, and cluster ions as well as ionic complexes.

  14. Structure and magnetic properties of SiO{sub 2}/PCL novel sol–gel organic–inorganic hybrid materials

    Energy Technology Data Exchange (ETDEWEB)

    Catauro, Michelina, E-mail: michelina.catauro@unina2.it [Department of Industrial and Information Engineering, Second University of Naples, Via Roma 29, 81031 Aversa (Italy); Bollino, Flavia [Department of Industrial and Information Engineering, Second University of Naples, Via Roma 29, 81031 Aversa (Italy); Cristina Mozzati, Maria [Department of Physics, CNISM and INSTM, University of Pavia, Via Bassi 6, 27100 Pavia (Italy); Ferrara, Chiara; Mustarelli, Piercarlo [Department of Chemistry, Section of Physical Chemistry, University of Pavia and INSTM, Via Taramelli 16, 27100 Pavia (Italy)

    2013-07-15

    Organic–inorganic nanocomposite materials have been synthesized via sol–gel. They consist of an inorganic SiO{sub 2} matrix, in which different percentages of poly(ε-caprolactone) (PCL) have been incorporated. The formation of H-bonds among the carbonyl groups of the polymer chains and Si–OH group of the inorganic matrix has been proved by means of Fourier transform infrared spectroscopy (FT-IR) analysis and has been confirmed by solid-state nuclear magnetic resonance (NMR). X-Ray diffraction (XRD) analysis highlighted the amorphous nature of the synthesized materials. Scanning electron microscope (SEM) micrograph and atomic force microscope (AFM) topography showed their homogeneous morphology and nanostructure nature. Considering the opportunity to synthesize these hybrid materials under microgravity conditions by means of magnetic levitation, superconducting quantum interference device (SQUID) magnetometry has been used to quantify their magnetic susceptibility. This measure has shown that the SiO{sub 2}/PCL hybrid materials are diamagnetic and that their diamagnetic susceptibility is independent of temperature and increases with the PCL amount. - Graphical abstract: Characterization and magnetic properties of SiO{sub 2}/PCL organic–inorganic hybrid materials synthesized via sol–gel. FT-IR, Fourier transform infrared spectroscopy; solid-state NMR: solid-state nuclear magnetic resonance; SQUID: superconducting quantum interference device. - Highlights: • Sol–gel synthesis of SiO{sub 2}/PCL amorphous class I organic–inorganic hybrid materials. • FT-IR and NMR analyses show the hydrogen bonds formation between SiO{sub 2} and PCL. • AFM and SEM analyses confirm that the SiO{sub 2}/PCL are homogenous hybrid materials. • The SQUID measures show that the simples are diamagnetic. • Diamagnetic susceptibility of SiO{sub 2}/PCL materials increases with the PCL amount.

  15. A validated hybrid quadrupole linear ion-trap LC-MS method for the analysis of morphine and morphine glucuronides applied to opiate deaths.

    Science.gov (United States)

    Taylor, Kerry; Elliott, Simon

    2009-05-30

    A hybrid quadrupole linear ion-trap mass spectrometer using an electrospray ionisation ion source coupled to a HPLC system has been used to develop a method which can accurately measure morphine, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) in plasma, whole blood and post-mortem blood following solid-phase extraction. The method can also qualitatively detect various other opioids and related compounds including: codeine, dihydrocodeine (and metabolites), noscapine, papaverine and 6-acetylmorphine (6-AM). The method has been favourably compared to an existing laboratory method using a now discontinued radio-immunoassay technique. The advantage of measuring the glucuronides directly rather than following deconjugation by beta-glucuronidase has also been shown. Detection and quantification of compounds was achieved using multiple reaction monitoring (MRM) incorporating the use of deuterated morphine and M3G as internal standards. Precision and accuracy was determined to be less than 10% at both high and low levels for all analytes and the calibration curve was deemed linear over an acceptable range. Recovery in blood was greater than 90% and ion suppression/enhancement was shown to be less than 15%. This method was applied to over 130 post-mortem cases involving the use of heroin, prescribed morphine and codeine. The range of concentrations of morphine, M3G and M6G was large (particularly in heroin and prescribed morphine cases), reflecting the many different factors involved with therapeutic use or fatal opiate poisonings, including tolerance associated with regular use, variable dose regimens and co-administration of other drugs. Detection of other constituents of the opium poppy such as noscapine and papaverine and metabolites of diacetylmorphine in the blood (6-AM) was useful in determining the source of the morphine (i.e. illicit heroin) and the rapidity of death after administration.

  16. Multiple and sequential data acquisition method: an improved method for fragmentation and detection of cross-linked peptides on a hybrid linear trap quadrupole Orbitrap Velos mass spectrometer.

    Science.gov (United States)

    Rudashevskaya, Elena L; Breitwieser, Florian P; Huber, Marie L; Colinge, Jacques; Müller, André C; Bennett, Keiryn L

    2013-02-05

    The identification and validation of cross-linked peptides by mass spectrometry remains a daunting challenge for protein-protein cross-linking approaches when investigating protein interactions. This includes the fragmentation of cross-linked peptides in the mass spectrometer per se and following database searching, the matching of the molecular masses of the fragment ions to the correct cross-linked peptides. The hybrid linear trap quadrupole (LTQ) Orbitrap Velos combines the speed of the tandem mass spectrometry (MS/MS) duty circle with high mass accuracy, and these features were utilized in the current study to substantially improve the confidence in the identification of cross-linked peptides. An MS/MS method termed multiple and sequential data acquisition method (MSDAM) was developed. Preliminary optimization of the MS/MS settings was performed with a synthetic peptide (TP1) cross-linked with bis[sulfosuccinimidyl] suberate (BS(3)). On the basis of these results, MSDAM was created and assessed on the BS(3)-cross-linked bovine serum albumin (BSA) homodimer. MSDAM applies a series of multiple sequential fragmentation events with a range of different normalized collision energies (NCE) to the same precursor ion. The combination of a series of NCE enabled a considerable improvement in the quality of the fragmentation spectra for cross-linked peptides, and ultimately aided in the identification of the sequences of the cross-linked peptides. Concurrently, MSDAM provides confirmatory evidence from the formation of reporter ions fragments, which reduces the false positive rate of incorrectly assigned cross-linked peptides.

  17. Selenium metabolomics in yeast using complementary reversed-phase/hydrophilic ion interaction (HILIC) liquid chromatography-electrospray hybrid quadrupole trap/Orbitrap mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Arnaudguilhem, C.; Bierla, K.; Ouerdane, L.; Preud' homme, H. [CNRS/UPPA, Laboratoire de Chimie Analytique Bio-inorganique et Environnement, UMR 5254, Helioparc, 2, Av. Pr. Angot, 64053 Pau (France); Yiannikouris, A. [Alltech Inc., 3031 Catnip Hill Pike, Nicholasville, KY (United States); Lobinski, R., E-mail: ryszard.lobinski@univ-pau.fr [CNRS/UPPA, Laboratoire de Chimie Analytique Bio-inorganique et Environnement, UMR 5254, Helioparc, 2, Av. Pr. Angot, 64053 Pau (France); Chair of Analytical Chemistry, Warsaw University of Technology, 00-664 Warszawa (Poland)

    2012-12-13

    Highlights: Black-Right-Pointing-Pointer The use of bimodal chromatographic separation enlarged amount of compounds identified. Black-Right-Pointing-Pointer The method allowed the largest scale ever (>60 compounds) speciation analysis of selenium metabolites in Se-rich yeast. Black-Right-Pointing-Pointer The estimated concentration of compounds was given. - Abstract: A high efficiency chromatographic separation on a porous graphitic carbon stationary phase was developed for a large-scale separation of selenium metabolites in Se-rich yeast prior to their identification by electrospray hybrid quadrupole trap/Orbitrap mass spectrometry (Orbitrap MS{sup n}). The reversed-phase (RP) separation mode offered distinctly higher separation efficiency than the hydrophilic ion interaction (HILIC) mode. The latter was nevertheless complementary and useful to validate the detection of several compounds. The method allowed the detection of 64 metabolites including 30 Se-Se or Se-S conjugates (3 triple S/Se/S ones) and 14 selenoethers. 21 previously unreported metabolites were detected on the basis of the selenium isotopic pattern usually matched with the sub-ppm mass accuracy. 9 of these metabolites were subsequently identified using the multi-stage high mass accuracy (<5 ppm) mass spectrometry. The identified metabolites (and their groups) were quantified on-line by ICP-MS fitted with a frequency-matching generator allowing a quasi-uniform response over the large (20-90%) acetonitrile mobile phase concentration range. The morphology of HPLC-ICP-MS chromatograms was remarkably similar to that of HPLC multi-ion extracted ESI-MS chromatograms. The detection limits obtained by ICP MS and ESI MS were 1 and 2 ppb, respectively.

  18. Design and parameter estimation of hybrid magnetic bearings for blood pump applications

    Science.gov (United States)

    Lim, Tau Meng; Zhang, Dongsheng; Yang, Juanjuan; Cheng, Shanbao; Low, Sze Hsien; Chua, Leok Poh; Wu, Xiaowei

    2009-10-01

    This paper discusses the design and parameter estimation of the dynamics characteristics of a high-speed hybrid magnetic bearings (HMBs) system for axial flow blood pump applications. The rotor/impeller of the pump is driven by a three-phase permanent magnet (PM) brushless and sensorless DC motor. It is levitated by two HMBs at both ends in five-degree-of-freedom with proportional-integral-derivative (PID) controllers; among which four radial directions are actively controlled and one axial direction is passively controlled. Test results show that the rotor can be stably supported to speeds of 14,000 rpm. The frequency domain parameter estimation technique with statistical analysis is adopted to validate the stiffness and damping coefficients of the HMBs system. A specially designed test rig facilitated the estimation of the bearing's coefficients in air—in both the radial and axial directions. The radial stiffness of the HMBs is compared to the Ansoft's Maxwell 2D/3D finite element magnetostatic results. Experimental estimation showed that the dynamics characteristics of the HMBs system are dominated by the frequency-dependent stiffness coefficients. The actuator gain was also successfully calibrated and may potentially extend the parameter estimation technique developed in the study of identification and monitoring of the pump's dynamics properties under normal operating conditions with fluid.

  19. Design, manufacture and performance evaluation of HTS electromagnets for the hybrid magnetic levitation system

    Energy Technology Data Exchange (ETDEWEB)

    Chu, S.Y.; Hwang, Y.J.; Choi, S.; Na, J.B.; Kim, Y.J.; Chang, K.S. [School of Electrical and Electronic Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of); Bae, D.K. [Chungju National University, Chungju 380-702 (Korea, Republic of); Lee, C.Y. [Ultra High-Speed Train Research Department, Korea Railroad Research Institute, Uiwang-Si 437-757 (Korea, Republic of); Ko, T.K., E-mail: tkko@yonsei.ac.kr [School of Electrical and Electronic Engineering, Yonsei University, Seoul 120-749 (Korea, Republic of)

    2011-11-15

    A high speed electromagnetic suspension (EMS) maglev has emerged as the solution to speed limit problem that conventional high-speed railroad has. In the EMS maglev, small levitation gap needs uniform guide-way which leads to increase the construction cost. The large levitation gap can reduce the construction cost. However it is hard for normal conducting electromagnet to produce larger magneto-motive force (MMF) for generating levitation force as increased levitation gap. This is because normal conductors have limited rating current to their specific volume. Therefore, the superconducting electromagnet can be one of the solutions for producing both large levitation gap and sufficient MMF. The superconducting electromagnets have incomparably high allowable current density than what normal conductors have. In this paper, the prototype of high temperature superconducting (HTS) electromagnets were designed and manufactured applicable to hybrid electromagnetic suspension system (H-EMS). The H-EMS consists of control coils for levitation control and superconducting coils for producing MMF for levitation. The required MMF for generating given levitation force was calculated by both equations of ideal U-core magnet and magnetic field analysis using the finite element method (FEM). The HTS electromagnets were designed as double pancakes with Bi-2223/Ag tapes. Experiments to confirm its operating performance were performed in liquid nitrogen (LN{sub 2}).

  20. Study of Lower Hybrid Frequency Turbulence in the Magnetic Reconnection Experiment (MRX)

    Science.gov (United States)

    Dorfman, S. E.; Ji, H.; Roytershteyn, V.; Yamada, M.; Daughton, W. S.; Yoo, J.; Oz, E.; Tharp, T.; Lawrence, E. E.; Myers, C.

    2010-12-01

    One of the key open questions in magnetic reconnection is the nature of the mechanism that governs the reconnection rate in real astrophysical and laboratory systems. Comparisons between fully kinetic 2-D simulations of the Magnetic Reconnection Experiment (MRX) and experimental data indicate that three-dimensional dynamics, such as current layer disruptions recently observed in MRX, may play a key role in resolving an important discrepancy in the reconnection rate and layer width [1,2,3]. These disruptions are often associated with fluctuations in the lower hybrid frequency range and a rapid local reconnection rate. Fluctuations are observed not only in MRX [4], but also in space [5] and 3-D kinetic simulations. Comparison of fluctuation characteristics between the three domains may shed light on the underlying physics. In both the simulation and the experiments, the fluctuations are related to density gradients across the layer. The frequency range is similarly broadband up to the lower hybrid range, and the phase velocities are comparable in appropriately normalized units. However, while the electron drift speed is comparable to the phase velocity at the layer center in the experiment (consistent with previous MRX results [4]), the drift speed in the simulations is considerably larger. Furthermore, the fluctuations observed in the experiment are fully turbulent with correlation lengths the same order as the wavelength while those observed in the simulations and in space are more coherent. Some discharges also display "O-point" signatures consistent with magnetic island like structures. The present research explores the relationship between the disruptions and fluctuations in the context of the reconnection rate problem. Experiments are ongoing to determine what physics is responsible for the broader current layers (and correspondingly smaller drift speeds) observed in the experiment. [1] Y. Ren, et al., Phys. Plasmas 15, 082113 (2008). [2] S. Dorfman, et al

  1. Search for trapped antihydrogen

    Science.gov (United States)

    Andresen, G. B.; Ashkezari, M. D.; Baquero-Ruiz, M.; Bertsche, W.; Bowe, P. D.; Bray, C. C.; Butler, E.; Cesar, C. L.; Chapman, S.; Charlton, M.; Fajans, J.; Friesen, T.; Fujiwara, M. C.; Gill, D. R.; Hangst, J. S.; Hardy, W. N.; Hayano, R. S.; Hayden, M. E.; Humphries, A. J.; Hydomako, R.; Jonsell, S.; Jørgensen, L. V.; Kurchaninov, L.; Lambo, R.; Madsen, N.; Menary, S.; Nolan, P.; Olchanski, K.; Olin, A.; Povilus, A.; Pusa, P.; Robicheaux, F.; Sarid, E.; Seif El Nasr, S.; Silveira, D. M.; So, C.; Storey, J. W.; Thompson, R. I.; van der Werf, D. P.; Wilding, D.; Wurtele, J. S.; Yamazaki, Y.; Alpha Collaboration

    2011-01-01

    We present the results of an experiment to search for trapped antihydrogen atoms with the ALPHA antihydrogen trap at the CERN Antiproton Decelerator. Sensitive diagnostics of the temperatures, sizes, and densities of the trapped antiproton and positron plasmas have been developed, which in turn permitted development of techniques to precisely and reproducibly control the initial experimental parameters. The use of a position-sensitive annihilation vertex detector, together with the capability of controllably quenching the superconducting magnetic minimum trap, enabled us to carry out a high-sensitivity and low-background search for trapped synthesised antihydrogen atoms. We aim to identify the annihilations of antihydrogen atoms held for at least 130 ms in the trap before being released over ∼30 ms. After a three-week experimental run in 2009 involving mixing of 10 7 antiprotons with 1.3×10 positrons to produce 6×10 antihydrogen atoms, we have identified six antiproton annihilation events that are consistent with the release of trapped antihydrogen. The cosmic ray background, estimated to contribute 0.14 counts, is incompatible with this observation at a significance of 5.6 sigma. Extensive simulations predict that an alternative source of annihilations, the escape of mirror-trapped antiprotons, is highly unlikely, though this possibility has not yet been ruled out experimentally.

  2. Search for magnetic monopoles with the MoEDAL prototype trapping detector in 8 TeV proton-proton collisions at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Acharya, B. [Theoretical Particle Physics & Cosmology Group, Physics Dept., King’s College London (United Kingdom); International Centre for Theoretical Physics, Trieste (Italy); Alexandre, J. [Theoretical Particle Physics & Cosmology Group, Physics Dept., King’s College London (United Kingdom); Bendtz, K. [Physics Department, Stockholm University, Stockholm (Sweden); Benes, P. [IEAP, Czech Technical University in Prague (Czech Republic); Collaboration: The MoEDAL collaboration; and others

    2016-08-10

    The MoEDAL experiment is designed to search for magnetic monopoles and other highly-ionising particles produced in high-energy collisions at the LHC. The largely passive MoEDAL detector, deployed at Interaction Point 8 on the LHC ring, relies on two dedicated direct detection techniques. The first technique is based on stacks of nuclear-track detectors with surface area ∼18 m{sup 2}, sensitive to particle ionisation exceeding a high threshold. These detectors are analysed offline by optical scanning microscopes. The second technique is based on the trapping of charged particles in an array of roughly 800 kg of aluminium samples. These samples are monitored offline for the presence of trapped magnetic charge at a remote superconducting magnetometer facility. We present here the results of a search for magnetic monopoles using a 160 kg prototype MoEDAL trapping detector exposed to 8 TeV proton-proton collisions at the LHC, for an integrated luminosity of 0.75 fb{sup −1}. No magnetic charge exceeding 0.5g{sub D} (where g{sub D} is the Dirac magnetic charge) is measured in any of the exposed samples, allowing limits to be placed on monopole production in the mass range 100 GeV≤m≤ 3500 GeV. Model-independent cross-section limits are presented in fiducial regions of monopole energy and direction for 1g{sub D}≤|g|≤6g{sub D}, and model-dependent cross-section limits are obtained for Drell-Yan pair production of spin-1/2 and spin-0 monopoles for 1g{sub D}≤|g|≤4g{sub D}. Under the assumption of Drell-Yan cross sections, mass limits are derived for |g|=2g{sub D} and |g|=3g{sub D} for the first time at the LHC, surpassing the results from previous collider experiments.

  3. PHOTOSPHERE EMISSION FROM A HYBRID RELATIVISTIC OUTFLOW WITH ARBITRARY DIMENSIONLESS ENTROPY AND MAGNETIZATION IN GRBs

    Energy Technology Data Exchange (ETDEWEB)

    Gao, He [Current address: Department of Astronomy and Astrophysics, Department of Physics, Center for Particle Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States); Zhang, Bing, E-mail: gaohe@physics.unlv.edu, E-mail: zhang@physics.unlv.edu, E-mail: hug18@psu.edu [Department of Physics and Astronomy, University of Nevada, Las Vegas, NV 89154 (United States)

    2015-03-10

    In view of the recent Fermi observations of gamma-ray burst (GRB) prompt emission spectra, we develop a theory of photosphere emission of a hybrid relativistic outflow with a hot fireball component (defined by dimensionless entropy η) and a cold Poynting-flux component (defined by magnetization σ{sub 0} at the central engine). We consider the scenarios both without and with sub-photospheric magnetic dissipations. Based on a simplified toy model of jet dynamics, we develop two approaches: a 'bottom-up' approach to predict the temperature (for a non-dissipative photosphere) and luminosity of the photosphere emission and its relative brightness for a given pair of (η, σ{sub 0}); and a 'top-down' approach to diagnose central engine parameters (η and σ{sub 0}) based on the observed quasi-thermal photosphere emission properties. We show that a variety of observed GRB prompt emission spectra with different degrees of photosphere thermal emission can be reproduced by varying η and σ{sub 0} within the non-dissipative photosphere scenario. In order to reproduce the observed spectra, the outflows of most GRBs need to have a significant σ, both at the central engine and at the photosphere. The σ value at 10{sup 15} cm from the central engine (a possible non-thermal emission site) is usually also greater than unity, so that internal-collision-induced magnetic reconnection and turbulence (ICMART) may be the mechanism to power the non-thermal emission. We apply our top-down approach to GRB 110721A and find that the temporal evolution behavior of its blackbody component can be well interpreted with a time-varying (η, σ{sub 0}) at the central engine, instead of invoking a varying engine base size r {sub 0} as proposed by previous authors.

  4. Heat transfer and entropy generation analysis of hybrid graphene/Fe3O4 ferro-nanofluid flow under the influence of a magnetic field

    DEFF Research Database (Denmark)

    Mehrali, Mohammad; Sadeghinezhad, Emad; Akhiani, Amir Reza

    2017-01-01

    The heat transfer characteristics and entropy generation rate of hybrid graphene-magnetite nanofluids under forced laminar flow that subjected to the permanent magnetic fields were investigated. For this purpose, a nanoscale reduced graphene oxide-Fe3O4 hybrid was synthesized by using graphene...... oxide, iron salts and tannic acid as the reductant and stabilizer. The thermophysical and magnetic properties of the hybrid nanofluid have been widely characterized and thermal conductivity has shown an enhancement of 11%. The experimental results indicated that the heat transfer enhancement of hybrid...

  5. Experimental studies of highly charged ions in a Penning trap for the measurement of electron magnetic moments by double-resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lindenfels, David-Friedrich von

    2015-11-18

    A precise measurement of bound-electron g factors in highly charged ions provides stringent tests for state-of-the-art theoretical calculations, such as relativistic electron-correlation, bound-state QED, and higher-order Zeeman effects. We excite the fine-structure transition of boronlike argon ({sup 40}Ar{sup 13+}) with laser radiation and probe microwave transitions between Zeeman sub-levels in the magnetic field of a Penning trap. From this laser-microwave double-resonance technique the g factor can be determined on a ppb level of accuracy in our apparatus. We have built a novel 'half-open' Penning trap with high fluorescence-detection efficiency and an integrated electron-beam ion source for production of highly charged ions from gas, injected through a cryogenic valve. In the future, heavier ions shall be captured from the HITRAP facility at GSI and the method shall be applied to hyperfine-structure transitions of hydrogenlike bismuth ({sup 209}Bi{sup 82+}) in order to measure electronic and nuclear magnetic moments. This thesis presents experimental developments as well as production, cooling, transport, and long-term storage of highly charged argon ions.

  6. Influence of soft ferromagnetic sections on the magnetic flux density profile of a large grain, bulk Y-Ba-Cu-O superconductor

    OpenAIRE

    Philippe, Matthieu; Ainslie, Mark D.; Wera, Laurent; Fagnard, Jean-François; Dennis, Anthony; Shi, Yunhua; Cardwell, David A.; Vanderheyden, Benoît; Vanderbemden, Philippe

    2015-01-01

    Bulk, high temperature superconductors have significant potential for use as powerful permanent magnets in a variety of practical applications due to their ability to trap record magnetic fields. In this paper, soft ferromagnetic sections are combined with a bulk, large grain Y-Ba-Cu-O (YBCO) high temperature superconductor to form superconductor/ferromagnet (SC/FM) hybrid structures. We study how the ferromagnetic sections influence the shape of the profile of the trapped magnetic induction ...

  7. Efficient boron abstraction using honeycomb-like porous magnetic hybrids: Assessment of techno-economic recovery of boric acid.

    Science.gov (United States)

    Oladipo, Akeem Adeyemi; Gazi, Mustafa

    2016-12-01

    Porous magnetic hybrids were synthesized and functionalized with glycidol to produce boron-selective adsorbent. The magnetic hybrid (MH) comparatively out-performed the existing expensive adsorbents. MH had a saturation magnetisation of 63.48 emu/g and average pore diameter ranging from meso to macropores. The magnetic hybrids showed excellent selectivity towards boron and resulted in 79-93% boron removal even in the presence of competing metal ions (Na(+) and Cr(2+)). Experiments were performed in a column system, and breakthrough time was observed to increase with bed depths and decreased with flow rates. The batch experiments revealed that 60 min was enough to achieve equilibrium, and the level of boron sorption was 108.5 mg/g from a synthetic solution. Several adsorption-desorption cycles were performed using a simple acid-water treatment and evaluated using various kinetic models. The spent adsorbents could be separated easily from the mixture by an external magnetic field. The cost-benefit analysis was performed for the treatment of 72 m(3)/year boron effluent, including five years straight line depreciation charges of equipment. The net profit and standard percentage confirmed that the recovery process is economically feasible.

  8. Discriminating between antihydrogen and mirror-trapped antiprotons in a minimum-B trap

    CERN Document Server

    Amole, C; Ashkezari, M D; Baquero-Ruiz, M; Bertsche, W; Butler, E; Cesar, C L; Chapman, S; Charlton, M; Deller, A; Eriksson, S; Fajans, J; Friesen, T; Fujiwara, M C; Gill, D R; Gutierrez, A; Hangst, J S; Hardy, W N; Hayden, M E; Humphries, A J; Hydomako, R; Kurchaninov, L; Jonsell, S; Madsen, N; Menary, S; Nolan, P; Olchanski, K; Olin, A; Povilus, A; Pusa, P; Robicheaux, F; Sarid, E; Silveira, D M; So, C; Storey, J W; Thompson, R I; van der Werf, D P; Wurtele, J S

    2012-01-01

    Recently, antihydrogen atoms were trapped at CERN in a magnetic minimum (minimum-B) trap formed by superconducting octupole and mirror magnet coils. The trapped antiatoms were detected by rapidly turning off these magnets, thereby eliminating the magnetic minimum and releasing any antiatoms contained in the trap. Once released, these antiatoms quickly hit the trap wall, whereupon the positrons and antiprotons in the antiatoms annihilated. The antiproton annihilations produce easily detected signals; we used these signals to prove that we trapped antihydrogen. However, our technique could be confounded by mirror-trapped antiprotons, which would produce seemingly-identical annihilation signals upon hitting the trap wall. In this paper, we discuss possible sources of mirror-trapped antiprotons and show that antihydrogen and antiprotons can be readily distinguished, often with the aid of applied electric fields, by analyzing the annihilation locations and times. We further discuss the general properties of antipr...

  9. Wide Variety of Experiments Using a Cryogen-Free 27.5 T Hybrid Magnet and a Cryogen-Free 18.1 T Superconducting Magnet

    Science.gov (United States)

    Watanabe, K.; Awaji, S.; Oguro, H.

    2013-03-01

    A cryogen-free hybrid magnet without liquid helium for operation, generating 27.5 T in a 32 mm room temperature bore of an 8 MW water-cooled resistive insert magnet in an 8.5 T background field of a cryogen-free superconducting outsert magnet, is being operated for basic research at low temperatures down to 17 mK in combination with a dilution refrigerator. In addition, we are developing functional materials using a differential thermal analysis DTA at high temperatures up to 1473 K in high fields up to 27 T. This cryogen-free hybrid magnet will be upgraded to generate 29 T by improving the outer superconducting magnet. A cryogen-free 18.1 T superconducting magnet with a 52 mm room temperature experimental bore, consisting of a Bi2Sr2Ca2Cu3O10 (Bi2223) insert coil, has been developed using a GM-JT cryocooler. Recently, bronze-tape-laminated Bi2223 has revealed excellent irreversible stress tolerance of 250 MPa at 77 K. In addition, the critical current properties for recent Bi2223 tapes are largely improved from 200 to 400 A/cm-width at 77 K in a self-field. Therefore, the stainless steel reinforcement tape incorporated for the previous Bi2223 insert coil is no longer needed for a new Bi2223 one. A new Bi2223 insert coil with almost the same size as the existing insert coil can generate two times higher fields at the elevated operation current from 162 to 191 A. An upgraded cryogen-free superconducting magnet can offer a long-term experiment at the constant magnetic field of 20 T for an in-field heat-treatment investigation.

  10. A Smart Polymer Composite Based on a NiTi Ribbon and a Magnetic Hybrid Material for Actuators with Multiphysic Transduction

    Directory of Open Access Journals (Sweden)

    Beatriz López-Walle

    2015-12-01

    Full Text Available A smart composite material constituted of a magnetic hybrid film and a NiTi shape memory alloy (SMA ribbon was obtained and characterized. The magnetic hybrid film was joined to the NiTi ribbon in order to combine the properties of both materials. This new composite material combines magnetic properties of the hybrid film, (Fe2O3-CMC/(polyvinyl butyral, and the shape memory properties of the NiTi ribbon, which has a chemical composition of Ti-50.13 at. % Ni. This smart composite material has a mass of 18.3% NiTi ribbon and 81.7% magnetic hybrid film. Results obtained by DSC show that the smart composite material presents a small delay of transformation during warming and cooling because the magnetic hybrid film acts like a thermal insulator. Thermomechanical results indicate that the hybrid material also acts as a mechanical reinforcement, since it is observed that the Stress-Assisted Two-Way Memory Effect (SATWME of the smart composite is lower than the SATWME of the SMA ribbon. The density current values of phase transformations were clearly identified with a thermomechanical apparatus developed in our laboratory. Finally, displacements of the smart composite material in cantilever configuration are obtained by applying an external magnetic field. All these results demonstrate that the smart composite material can be activated by temperature, electrical current, stress, and/or magnetic field, offering good expectations for actuating applications with multiphysic transduction.

  11. Material and cooling requirements for poly-Bitter resistive magnets and hybrid inserts generating continuous fields up to 50 T

    Energy Technology Data Exchange (ETDEWEB)

    Gao, B.J.; Bird, M.D.; Eyssa, Y.M.; Schneider-Muntau, H.J. [National High Magnetic Field Lab., Tallahassee, FL (United States)

    1994-07-01

    The new National High Magnetic Field Laboratory (NHMFL), equipped with a 40 MW DC power supply, will design and construct the next generation of high field resistive magnets and hybrid inserts generating DC fields up to 50 T. The authors present a study on the required materials and the necessary cooling characteristics, these magnets need. The configuration selected for this study consists of a combination of thin poly-Bitter and thick Bitter coils optimized in dimensions and power under constraint of maximum design stress and heat removal to obtain maximum field. The study shows that each design requires a different optimum ratio of conductor strength to electrical conductivity and that efficient cooling is only advantageous if strong copper alloys are used. For efficient use of the available power the development of new high strength, high conductivity materials will be necessary. Equally important are improvements in the heat transfer characteristics of these high power density magnets.

  12. Shimming with permanent magnets for the x-ray detector in a hybrid x-ray/ MR system.

    Science.gov (United States)

    Wen, Zhifei; Fahrig, Rebecca; Williams, Scott T; Pelc, Norbert J

    2008-09-01

    In this x-ray/MR hybrid system an x-ray flat panel detector is placed under the patient cradle, close to the MR volume of interest (VOI), where the magnetic field strength is approximately 0.5 T. Immersed in this strong field, several electronic components inside the detector become magnetized and create an additional magnetic field that is superimposed on the original field of the MR scanner. Even after linear shimming, the field homogeneity of the MR scanner remains disrupted by the detector. The authors characterize the field due to the detector with the field of two magnetic dipoles and further show that two sets of permanent magnets (NdFeB) can withstand the main magnetic field and compensate for the nonlinear components of the additional field. The ideal number of magnets and their locations are calculated based on a field map measured with the detector in place. Experimental results demonstrate great promise for this technique, which may be useful in many settings where devices with magnetic components need to be placed inside or close to an MR scanner.

  13. Design and Mathematical Analysis of a Novel Reluctance Force-Type Hybrid Magnetic Bearing for Flywheel with Gimballing Capability

    Directory of Open Access Journals (Sweden)

    Chun'e Wang

    2013-01-01

    Full Text Available Magnetically suspended flywheel (MSFW with gimballing capability fulfills requirements of precision and maneuvers for space applications. A novel reluctance force-type hybrid magnetic bearing (RFHMB is presented based on analysis of demerits of Lorentz force-type magnetic bearing and common RFHMB. It features that radial and axial magnetic bearing units are integrated into a compact assembly with four separate biased permanent magnets and two conical stators; four radial poles with shoes and rotor made of iron-based amorphousness can reduce eddy loss. Equivalent magnetic circuits of permanent magnets and their control currents are presented. Simulation results indicate flux density fluctuates from 0.272 T to 0.41 T; rotor tilting does not affect the suspension force when rotor only tilts around X-axis or Y-axis. When rotor drifts in X, Y, or Z direction and tilts around X-axis or Y-axis simultaneously, force in corresponding directions slightly increases with tilting angle’s enlargement, but the maximum change does not exceed 14%. Additional tilting torque mainly determined by uniformity of flux density in conical air gaps is 0.05 Nm which is far smaller than 11 Nm in common RFHMB; magnetic suspension force is effectively decoupled among X, Y, and Z directions; results prove that MSFW with gimballing capability theoretically meets maneuvering requirement of spacecraft.

  14. Parameter estimation and actuator characteristics of hybrid magnetic bearings for axial flow blood pump applications.

    Science.gov (United States)

    Lim, Tau Meng; Cheng, Shanbao; Chua, Leok Poh

    2009-07-01

    Axial flow blood pumps are generally smaller as compared to centrifugal pumps. This is very beneficial because they can provide better anatomical fit in the chest cavity, as well as lower the risk of infection. This article discusses the design, levitated responses, and parameter estimation of the dynamic characteristics of a compact hybrid magnetic bearing (HMB) system for axial flow blood pump applications. The rotor/impeller of the pump is driven by a three-phase permanent magnet brushless and sensorless motor. It is levitated by two HMBs at both ends in five degree of freedom with proportional-integral-derivative controllers, among which four radial directions are actively controlled and one axial direction is passively controlled. The frequency domain parameter estimation technique with statistical analysis is adopted to validate the stiffness and damping coefficients of the HMB system. A specially designed test rig facilitated the estimation of the bearing's coefficients in air-in both the radial and axial directions. Experimental estimation showed that the dynamic characteristics of the HMB system are dominated by the frequency-dependent stiffness coefficients. By injecting a multifrequency excitation force signal onto the rotor through the HMBs, it is noticed in the experimental results the maximum displacement linear operating range is 20% of the static eccentricity with respect to the rotor and stator gap clearance. The actuator gain was also successfully calibrated and may potentially extend the parameter estimation technique developed in the study of identification and monitoring of the pump's dynamic properties under normal operating conditions with fluid.

  15. Testing of a centrifugal blood pump with a high efficiency hybrid magnetic bearing.

    Science.gov (United States)

    Locke, Dennis H; Swanson, Erik S; Walton, James F; Willis, John P; Heshmat, Hooshang

    2003-01-01

    The purpose of this article is to present test results for a second generation, high efficiency, nonpulsatile centrifugal blood pump that is being developed for use as a left ventricular assist device (LVAD). The LVAD pump uses a hybrid passive-active magnetic bearing support system that exhibits extremely low power loss, low vibration, and high reliability under transient conditions and varying pump orientations. A unique feature of the second generation design configuration is the very simple and direct flow path for both main and washing blood flows. The pump was tested in both vertical and horizontal orientations using a standard flow loop to demonstrate the performance and durability of the second generation LVAD. Steady state and transient orientation pump operating characteristics including pressure, flow, speed, temperatures, vibration, and rotor orientation were measured. During the tests, pump performance was mapped at several operating conditions including points above and below the nominal design of 5 L/min at 100 mm Hg pressure rise. Flow rates from 2 to 7 L/min and pressure rises from 50 to 150 mm Hg were measured. Pump speeds were varied during these tests from 2,500 to 3,500 rpm. The nominal design flow of 5 L/min at 100 mm Hg pressure rise was successfully achieved at the design speed of 3,000 rpm. After LVAD performance testing, both 28 day continuous duty and 5 day transient orientation durability tests were completed without incident. A hydrodynamic backup bearing design feasibility study was also conducted. Results from this design study indicate that an integral hydrodynamic backup bearing may be readily incorporated into the second generation LVAD and other magnetically levitated pump rotors.

  16. Self-assembled organic–inorganic magnetic hybrid adsorbent ferrite based on cyclodextrin nanoparticles

    Directory of Open Access Journals (Sweden)

    Ângelo M. L. Denadai

    2012-11-01

    Full Text Available Organic–inorganic magnetic hybrid materials (MHMs combine a nonmagnetic and a magnetic component by means of electrostatic interactions or covalent bonds, and notable features can be achieved. Herein, we describe an application of a self-assembled material based on ferrite associated with β-cyclodextrin (Fe-Ni/Zn/βCD at the nanoscale level. This MHM and pure ferrite (Fe-Ni/Zn were used as an adsorbent system for Cr3+ and Cr2O72− ions in aqueous solutions. Prior to the adsorption studies, both ferrites were characterized in order to determine the particle size distribution, morphology and available binding sites on the surface of the materials. Microscopy analysis demonstrated that both ferrites present two different size domains, at the micro- and nanoscale level, with the latter being able to self-assemble into larger particles. Fe-Ni/Zn/βCD presented smaller particles and a more homogeneous particle size distribution. Higher porosity for this MHM compared to Fe-Ni/Zn was observed by Brunauer–Emmett–Teller isotherms and positron-annihilation-lifetime spectroscopy. Based on the pKa values, potentiometric titrations demonstrated the presence of βCD in the inorganic matrix, indicating that the lamellar structures verified by transmission electronic microscopy can be associated with βCD assembled structures. Colloidal stability was inferred as a function of time at different pH values, indicating the sedimentation rate as a function of pH. Zeta potential measurements identified an amphoteric behavior for the Fe-Ni/Zn/βCD, suggesting its better capability to remove ions (cations and anions from aqueous solutions compared to that of Fe-Ni/Zn.

  17. Food contaminant analysis at ultra-high mass resolution: application of hybrid linear ion trap - orbitrap mass spectrometry for the determination of the polyether toxins, azaspiracids, in shellfish.

    LENUS (Irish Health Repository)

    2010-10-30

    The biotoxins, azaspiracids (AZAs), from marine phytoplankton accumulate in shellfish and affect human health by causing severe gastrointestinal disturbance, diarrhea, nausea and vomiting. Specific and sensitive methods have been developed and validated for the determination of the most commonly occurring azaspiracid analogs. An LTQ Orbitrap mass spectrometer is a hybrid instrument that combines linear ion trap (LIT) mass spectrometry (MS) with high-resolution Fourier transform (FT) MS and this was exploited to perform simultaneous ultra-high-resolution full-scan MS analysis and collision-induced dissociation (CID) tandem mass spectrometry (MS\\/MS). Using the highest mass resolution setting (100,000 FWHM) in full-scan mode, the methodology was validated for the determination of six AZAs in mussel (Mytilus galloprovincialis) tissue extracts. Ultra-high mass resolution, together with a narrow mass tolerance window of ±2 mDa, dramatically improved detection sensitivity. In addition to employing chromatographic resolution to distinguish between the isomeric azaspiracid analogs, AZA1\\/AZA6 and AZA4\\/AZA5, higher energy collisionally induced dissociation (HCD) fragmentation on selected precursor ions were performed in parallel with full-scan FTMS. Using HCD MS\\/MS, most precursor and product ion masses were determined within 1 ppm of the theoretical m\\/z values throughout the mass spectral range and this enhanced the reliability of analyte identity.For the analysis of mussels (M. galloprovincialis), the method limit of quantitation (LOQ) was 0.010 µg\\/g using full-scan FTMS and this was comparable with the LOQ (0.007 µg\\/g) using CID MS\\/MS. The repeatability data were; intra-day RSD% (1.8-4.4%; n = 6) and inter-day RSD% (4.7-8.6%; n = 3). Application of these methods to the analysis of mussels (M. edulis) that were naturally contaminated with azaspiracids, using high-resolution full-scan Orbitrap MS and low-resolution CID MS\\/MS, produced

  18. Jovian plasma torus interaction with Europa. Plasma wake structure and effect of inductive magnetic field: 3D Hybrid kinetic simulation

    CERN Document Server

    Lipatov, A S; Paterson, W R; Sittler, E C; Hartle, R E; Simpson, D G

    2012-01-01

    The hybrid kinetic model supports comprehensive simulation of the interaction between different spatial and energetic elements of the Europa moon-magnetosphere system with respect a to variable upstream magnetic field and flux or density distributions of plasma and energetic ions, electrons, and neutral atoms. This capability is critical for improving the interpretation of the existing Europa flyby measurements from the Galileo Orbiter mission, and for planning flyby and orbital measurements (including the surface and atmospheric compositions) for future missions. The simulations are based on recent models of the atmosphere of Europa (Cassidy et al., 2007; Shematovich et al., 2005). In contrast to previous approaches with MHD simulations, the hybrid model allows us to fully take into account the finite gyroradius effect and electron pressure, and to correctly estimate the ion velocity distribution and the fluxes along the magnetic field (assuming an initial Maxwellian velocity distribution for upstream backgr...

  19. Spin Seebeck effect and thermoelectric phenomena in superconducting hybrids with magnetic textures or spin-orbit coupling

    Science.gov (United States)

    Bathen, Marianne Etzelmüller; Linder, Jacob

    2017-01-01

    We theoretically consider the spin Seebeck effect, the charge Seebeck coefficient, and the thermoelectric figure of merit in superconducting hybrid structures including either magnetic textures or intrinsic spin-orbit coupling. We demonstrate that large magnitudes for all these quantities are obtainable in Josephson-based systems with either zero or a small externally applied magnetic field. This provides an alternative to the thermoelectric effects generated in high-field (~1 T) superconducting hybrid systems, which were recently experimentally demonstrated. The systems studied contain either conical ferromagnets, spin-active interfaces, or spin-orbit coupling. We present a framework for calculating the linear thermoelectric response for both spin and charge of a system upon applying temperature and voltage gradients based on quasiclassical theory which allows for arbitrary spin-dependent textures and fields to be conveniently incorporated.

  20. The ALPHA antihydrogen trapping apparatus

    Science.gov (United States)

    Amole, C.; Andresen, G. B.; Ashkezari, M. D.; Baquero-Ruiz, M.; Bertsche, W.; Bowe, P. D.; Butler, E.; Capra, A.; Carpenter, P. T.; Cesar, C. L.; Chapman, S.; Charlton, M.; Deller, A.; Eriksson, S.; Escallier, J.; Fajans, J.; Friesen, T.; Fujiwara, M. C.; Gill, D. R.; Gutierrez, A.; Hangst, J. S.; Hardy, W. N.; Hayano, R. S.; Hayden, M. E.; Humphries, A. J.; Hurt, J. L.; Hydomako, R.; Isaac, C. A.; Jenkins, M. J.; Jonsell, S.; Jørgensen, L. V.; Kerrigan, S. J.; Kurchaninov, L.; Madsen, N.; Marone, A.; McKenna, J. T. K.; Menary, S.; Nolan, P.; Olchanski, K.; Olin, A.; Parker, B.; Povilus, A.; Pusa, P.; Robicheaux, F.; Sarid, E.; Seddon, D.; Seif El Nasr, S.; Silveira, D. M.; So, C.; Storey, J. W.; Thompson, R. I.; Thornhill, J.; Wells, D.; van der Werf, D. P.; Wurtele, J. S.; Yamazaki, Y.

    2014-01-01

    The ALPHA collaboration, based at CERN, has recently succeeded in confining cold antihydrogen atoms in a magnetic minimum neutral atom trap and has performed the first study of a resonant transition of the anti-atoms. The ALPHA apparatus will be described herein, with emphasis on the structural aspects, diagnostic methods and techniques that have enabled antihydrogen trapping and experimentation to be achieved.

  1. The ALPHA antihydrogen trapping apparatus

    Energy Technology Data Exchange (ETDEWEB)

    Amole, C. [Department of Physics and Astronomy, York University, Toronto ON Canada, M3J 1P3 (Canada); Andresen, G.B. [Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark); Ashkezari, M.D. [Department of Physics, Simon Fraser University, Burnaby, BC Canada, V5A 1S6 (Canada); Baquero-Ruiz, M. [Department of Physics, University of California at Berkeley, Berkeley, CA 94720-7300 (United States); Bertsche, W. [Department of Physics, College of Science, Swansea University, Swansea SA2 8PP (United Kingdom); School of Physics and Astronomy, University of Manchester, Manchester M13 9PL (United Kingdom); The Cockcroft Institute, Warrington WA4 4AD (United Kingdom); Bowe, P.D. [Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark); Butler, E. [Physics Department, CERN, CH-1211 Geneva 23 (Switzerland); Capra, A. [Department of Physics and Astronomy, York University, Toronto ON Canada, M3J 1P3 (Canada); Carpenter, P.T. [Department of Physics, Auburn University, Auburn, AL 36849-5311 (United States); Cesar, C.L. [Instituto de Física, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-972 (Brazil); Chapman, S. [Department of Physics, University of California at Berkeley, Berkeley, CA 94720-7300 (United States); Charlton, M.; Deller, A.; Eriksson, S. [Department of Physics, College of Science, Swansea University, Swansea SA2 8PP (United Kingdom); Escallier, J. [Brookhaven National Laboratory, Upton, NY 11973 (United States); Fajans, J. [Department of Physics, University of California at Berkeley, Berkeley, CA 94720-7300 (United States); Friesen, T. [Department of Physics and Astronomy, University of Calgary, Calgary AB, Canada, T2N 1N4 (Canada); Fujiwara, M.C.; Gill, D.R. [TRIUMF, 4004 Wesbrook Mall, Vancouver BC, Canada V6T 2A3 (Canada); Gutierrez, A. [Department of Physics and Astronomy, University of British Columbia, Vancouver BC, Canada V6T 1Z4 (Canada); and others

    2014-01-21

    The ALPHA collaboration, based at CERN, has recently succeeded in confining cold antihydrogen atoms in a magnetic minimum neutral atom trap and has performed the first study of a resonant transition of the anti-atoms. The ALPHA apparatus will be described herein, with emphasis on the structural aspects, diagnostic methods and techniques that have enabled antihydrogen trapping and experimentation to be achieved.

  2. Design and Manufacture of 20 kA HTS Current Leads for a Hybrid Magnet System

    Science.gov (United States)

    Wesche, R.; Bruzzone, P.; March, S.; Vogel, M.; Ehmler, H.; Smeibidl, P.

    A new series connected 25 T hybrid magnet system is being developed by the Helmholtz Zentrum Berlin (HZB) for neutron scattering experiments. In collaboration with CRPP, high temperature superconducting (HTS) current leads have been developed for the powering of the outer superconducting coil. These HTS current leads, with a nominal current rating of 20 kA, have been designed and are being manufactured by CRPP, based on the design of the 18 kA EDIPO leads. Each of the two current leads consists of an HTS module cooled only by heat conduction from the cold end and a copper part actively cooled by helium gas of 44 K inlet temperature. To reach a temperature of 53.7 K at the warm end of the HTS a helium mass flow rate of 1.37 g/s per lead is required at a current of 20 kA. The estimated heat leak at the 4.5 K level caused only by heat conduction is as low as 1.4 W. The evolution of the temperatures in the case of a loss of flow has been calculated. In addition to the design, the main fabrication steps are described.

  3. Dressed topological insulators. Rashba impurity, Kondo effect, magnetic impurities, proximity-induced superconductivity, hybrid systems

    Energy Technology Data Exchange (ETDEWEB)

    Posske, Thore Hagen

    2016-02-26

    Topological insulators are electronic phases that insulate in the bulk and accommodate a peculiar, metallic edge liquid with a spin-dependent dispersion. They are regarded to be of considerable future use in spintronics and for quantum computation. Besides determining the intrinsic properties of this rather novel electronic phase, considering its combination with well-known physical systems can generate genuinely new physics. In this thesis, we report on such combinations including topological insulators. Specifically, we analyze an attached Rashba impurity, a Kondo dot in the two channel setup, magnetic impurities on the surface of a strong three-dimensional topological insulator, the proximity coupling of the latter system to a superconductor, and hybrid systems consisting of a topological insulator and a semimetal. Let us summarize our primary results. Firstly, we determine an analytical formula for the Kondo cloud and describe its possible detection in current correlations far away from the Kondo region. We thereby rely on and extend the method of refermionizable points. Furthermore, we find a class of gapless topological superconductors and semimetals, which accommodate edge states that behave similarly to the ones of globally gapped topological phases. Unexpectedly, we also find edge states that change their chirality when affected by sufficiently strong disorder. We regard the presented research helpful in future classifications and applications of systems containing topological insulators, of which we propose some examples.

  4. Superconductivity-induced magnetization depletion in a ferromagnet through an insulator in a ferromagnet-insulator-superconductor hybrid oxide heterostructure.

    Science.gov (United States)

    Prajapat, C L; Singh, Surendra; Paul, Amitesh; Bhattacharya, D; Singh, M R; Mattauch, S; Ravikumar, G; Basu, S

    2016-05-21

    Coupling between superconducting and ferromagnetic states in hybrid oxide heterostructures is presently a topic of intense research. Such a coupling is due to the leakage of the Cooper pairs into the ferromagnet. However, tunneling of the Cooper pairs though an insulator was never considered plausible. Using depth sensitive polarized neutron reflectivity we demonstrate the coupling between superconductor and magnetic layers in epitaxial La2/3Ca1/3MnO3 (LCMO)/SrTiO3/YBa2Cu3O7-δ (YBCO) hybrid heterostructures, with SrTiO3 as an intervening oxide insulator layer between the ferromagnet and the superconductor. Measurements above and below the superconducting transition temperature (TSC) of YBCO demonstrate a large modulation of magnetization in the ferromagnetic layer below the TSC of YBCO in these heterostructures. This work highlights a unique tunneling phenomenon between the epitaxial layers of an oxide superconductor (YBCO) and a magnetic layer (LCMO) through an insulating layer. Our work would inspire further investigations on the fundamental aspect of a long range order of the triplet spin-pairing in hybrid structures.

  5. Resonant photoluminescence and dynamics of a hybrid Mn hole spin in a positively charged magnetic quantum dot

    Science.gov (United States)

    Lafuente-Sampietro, A.; Boukari, H.; Besombes, L.

    2017-06-01

    We analyze, through resonant photoluminescence, the spin dynamics of an individual magnetic atom (Mn) coupled to a hole in a semiconductor quantum dot. The hybrid Mn hole spin and the positively charged exciton in a CdTe/ZnTe quantum dot form an ensemble of Λ systems which can be addressed optically. Autocorrelation of the resonant photoluminescence and resonant optical pumping experiments are used to study the spin relaxation channels in this multilevel spin system. We identified for the hybrid Mn hole spin an efficient relaxation channel driven by the interplay of the Mn hole exchange interaction and the coupling to acoustic phonons. We also show that the optical Λ systems are connected through inefficient spin flips than can be enhanced under weak transverse magnetic field. The dynamics of the resonant photoluminescence in a p -doped magnetic quantum dot is well described by a complete rate equation model. Our results suggest that long-lived hybrid Mn hole spin could be obtained in quantum dot systems with large heavy-hole/light-hole splitting.

  6. Superconductivity-induced magnetization depletion in a ferromagnet through an insulator in a ferromagnet-insulator-superconductor hybrid oxide heterostructure

    Science.gov (United States)

    Prajapat, C. L.; Singh, Surendra; Paul, Amitesh; Bhattacharya, D.; Singh, M. R.; Mattauch, S.; Ravikumar, G.; Basu, S.

    2016-05-01

    Coupling between superconducting and ferromagnetic states in hybrid oxide heterostructures is presently a topic of intense research. Such a coupling is due to the leakage of the Cooper pairs into the ferromagnet. However, tunneling of the Cooper pairs though an insulator was never considered plausible. Using depth sensitive polarized neutron reflectivity we demonstrate the coupling between superconductor and magnetic layers in epitaxial La2/3Ca1/3MnO3 (LCMO)/SrTiO3/YBa2Cu3O7-δ (YBCO) hybrid heterostructures, with SrTiO3 as an intervening oxide insulator layer between the ferromagnet and the superconductor. Measurements above and below the superconducting transition temperature (TSC) of YBCO demonstrate a large modulation of magnetization in the ferromagnetic layer below the TSC of YBCO in these heterostructures. This work highlights a unique tunneling phenomenon between the epitaxial layers of an oxide superconductor (YBCO) and a magnetic layer (LCMO) through an insulating layer. Our work would inspire further investigations on the fundamental aspect of a long range order of the triplet spin-pairing in hybrid structures.

  7. Magnetic order in hybrid frustrated magnets Gd2-xTbxTi2O7 (x = 0.2 and 0.5)

    Science.gov (United States)

    Orendáč, M.; Vrábel, P.; Orendáčová, A.; Prokleška, J.; Sechovský, V.; Singh, S.; Suryanarayanan, R.; Revcolevschi, A.

    2012-05-01

    We report on the specific heat, magnetization and ac susceptibility measurements of single crystals of hybrid frustrated magnets Gd1.8Tb0.2Ti2O7 and Gd1.5Tb0.5Ti2O7. The analysis of experimental data revealed that, although partial replacing of the Gd3+ ions by the Tb3+ ions in the Gd2Ti2O7 host lattice slightly enhances antiferromagnetic coupling, as inferred from the evolution of the paramagnetic Curie-Weiss temperature, the ordering temperature gradually decreases. Paramagnetic correlations introduced by the Tb3+ ions cause this perturbation, altering the effective further neighbor interactions and destabilizing the ground state in Gd2Ti2O7. In addition, the low-energy states of Gd2-xTbxTi2O7 are suggested to possess a nature different from those in parent members Tb2Ti2O7 and Gd2Ti2O7. Finally, the frequency-dependent magnetic susceptibility behavior in Gd1.5Tb0.5Ti2O7 is consistent with the formation of a spin-glass-like state indicating a pronounced slowing down of the dynamical response of the studied hybrid magnets.

  8. Investigating distribution patterns of airborne magnetic grains trapped in tree barks in Milan, Italy: insights for pollution mitigation strategies

    Science.gov (United States)

    Vezzola, Laura C.; Muttoni, Giovanni; Merlini, Marco; Rotiroti, Nicola; Pagliardini, Luca; Hirt, Ann M.; Pelfini, Manuela

    2017-08-01

    High levels of air particulate matter (PM) have been positively correlated with respiratory diseases. In this study, we performed a biomonitoring investigation using samples of bark obtained from trees in a selected study area in the city of Milan (northern Italy). Here, we analyse the magnetic and mineralogical properties of the outer and inner barks of 147 trees, finding that magnetite is the prevalent magnetic mineral. The relative concentration of magnetite is estimated in the samples using saturation isothermal remanent magnetization (SIRM) and hysteresis parameters. We also make a first-order estimate of absolute magnetite concentration from the SIRM. The spatial distribution of the measured magnetic parameters is evaluated as a function of the distance to the main sources of magnetic PM in the study area, for example, roads and tram stops. These results are compared with data from a substantially pollution-free control site in the Central Italian Alps. Magnetic susceptibility, SIRM and magnetite concentration are found to be the highest in the outer tree barks for samples that are closest to roads and especially tram stops. In contrast, the inner bark samples are weakly magnetic and are not correlated to the distance from magnetite PM sources. The results illustrate that trees play an important role acting as a sink for airborne PM in urban areas.

  9. Cyto/hemocompatible magnetic hybrid nanoparticles (Ag2S-Fe3O4) with luminescence in the near-infrared region as promising theranostic materials.

    Science.gov (United States)

    Hocaoglu, Ibrahim; Asik, Didar; Ulusoy, Gulen; Grandfils, Christian; Ojea-Jimenez, Isaac; Rossi, François; Kiraz, Alper; Doğan, Nurcan; Acar, Havva Yagci

    2015-09-01

    Small hybrid nanoparticles composed of highly biocompatible Ag2S quantum dots (QD) emitting in the near-infrared region and superparamagnetic iron oxide (SPION) are produced in a simple extraction method utilizing ligand exchange mechanism. Hybrid nanoparticles luminesce at the same wavelength as the parent QD, therefore an array of hybrid nanoparticles with emission between 840 and 912nm were easily produced. Such hybrid structures have (1) strong luminescence in the medical imaging window eliminating the autofluoresence of cells as effective optical probes, (2) strong magnetic response for magnetic targeting and (3) good cyto/hemocompatibility. An interesting size dependent cytotoxicity behavior was observed in HeLa and NIH/3T3 cell lines: smallest particles are internalized significantly more by both of the cell lines, yet showed almost no significant cytotoxicity in HeLa between 10 and 25μg/mL Ag concentration but were most toxic in NIH/3T3 cells. Cell internalization and hence the cytotoxicity enhanced when cells were incubated with the hybrid nanoparticles under magnetic field, especially with the hybrid nanoparticles containing larger amounts of SPION in the hybrid composition. These results prove them as effective optical imaging agents and magnetic delivery vehicles. Combined with the known advantages of SPIONs as a contrast agent in MRI, these particles are a step forward for new theranostics for multimode imaging and magnetic targeting.

  10. On a new scenario for the saturation of the low-threshold two-plasmon parametric decay instability of an extraordinary wave in the inhomogeneous plasma of magnetic traps

    Energy Technology Data Exchange (ETDEWEB)

    Gusakov, E. Z., E-mail: Evgeniy.Gusakov@mail.ioffe.ru; Popov, A. Yu., E-mail: a.popov@mail.ioffe.ru; Irzak, M. A., E-mail: irzak@mail.ioffe.ru [Russian Academy of Sciences, Ioffe Physical–Technical Institute (Russian Federation)

    2016-10-15

    The most probable scenario for the saturation of the low-threshold two-plasmon parametric decay instability of an electron cyclotron extraordinary wave has been analyzed. Within this scenario two upperhybrid plasmons at frequencies close to half the pump wave frequency radially trapped in the vicinity of the local maximum of the plasma density profile are excited due to the excitation of primary instability. The primary instability saturation results from the decays of the daughter upper-hybrid waves into secondary upperhybrid waves that are also radially trapped in the vicinity of the local maximum of the plasma density profile and ion Bernstein waves.

  11. On a new scenario for the saturation of the low-threshold two-plasmon parametric decay instability of an extraordinary wave in the inhomogeneous plasma of magnetic traps

    Science.gov (United States)

    Gusakov, E. Z.; Popov, A. Yu.; Irzak, M. A.

    2016-10-01

    The most probable scenario for the saturation of the low-threshold two-plasmon parametric decay instability of an electron cyclotron extraordinary wave has been analyzed. Within this scenario two upperhybrid plasmons at frequencies close to half the pump wave frequency radially trapped in the vicinity of the local maximum of the plasma density profile are excited due to the excitation of primary instability. The primary instability saturation results from the decays of the daughter upper-hybrid waves into secondary upperhybrid waves that are also radially trapped in the vicinity of the local maximum of the plasma density profile and ion Bernstein waves.

  12. A trapped magnetic field of 3 T in homogeneous, bulk MgB2 superconductors fabricated by a modified precursor infiltration and growth process

    Science.gov (United States)

    Bhagurkar, A. G.; Yamamoto, A.; Anguilano, L.; Dennis, A. R.; Durrell, J. H.; Babu, N. Hari; Cardwell, D. A.

    2016-03-01

    The wetting of boron with liquid magnesium is a critical factor in the synthesis of MgB2 bulk superconductors by the infiltration and growth (IG) process. Poor wetting characteristics can therefore result potentially in non-uniform infiltration, formation of defects in the final sample structure and poor structural homogeneity throughout the bulk material. Here we report the fabrication of near-net-shaped MgB2 bulk superconductors by a modified precursor infiltration and growth (MPIG) technique. A homogeneous bulk microstructure has subsequently been achieved via the uniform infiltration of Mg liquid by enriching pre-reacted MgB2 powder within the green precursor pellet as a wetting enhancer, leading to relatively little variation in superconducting properties across the entire bulk sample. Almost identical values of trapped magnetic field of 2.12 T have been measured at 5 K at both the top and bottom surfaces of a sample fabricated by the MPIG process, confirming the uniformity of the bulk microstructure. A maximum trapped field of 3 T has been measured at 5 K at the centre of a stack of two bulk MgB2 samples fabricated using this technique. A steady rise in trapped field was observed for this material with decreasing temperature down to 5 K without the occurrence of flux avalanches and with a relatively low field decay rate (1.5%/d). These properties are attributed to the presence of a fine distribution of residual Mg within the bulk microstructure generated by the MPIG processing technique.

  13. MAGNETIC AND PALAEOMAGNETIC STUDIES AS AN AID IN DECIPHERING GROUNDWATER FLOW: A CASE STUDY FROM DECCAN TRAPS

    Directory of Open Access Journals (Sweden)

    Poornachandra Rao G.V.S.

    2009-07-01

    Full Text Available This paper reports the utility of palaeomagnetic investigations first time in the ground water studies. The magnetic anomalies along with palaeomagnetic studies are used to locate barriers obstructing groundwater flow in a basaltic terrain. Magnetic anomalies in an area of around 4 sq. km in the university campus, Nanded, Maharashtra, India brought out two distinct anomaly closures that can be attributed to bodies with different directions of magnetizations. Palaeomagnetic investigations reveal that the basalts are almost uniformly magnetized, asserting that the anomalies come form the subsurface and the anomalous sources are attributed to weathering of basal basaltic flows. The difference between the measured palaeomagnetic directions of the surface rocks and the observed magnetic anomalies, in corroboration with local geomorphologic conditions and thenature of the basaltic flows in thin basaltic terrains suggest that subsurface weathering plays a major role in the ground water movement. This paper presents a novel idea on the utilization of the palaeomagnetic studies coupled with ground magnetic anomalies in deciphering groundwater flow.

  14. Retraction notice to "Measurements of total absolute collision cross section of ultracold Rb atom using magneto-optic and pure magnetic traps" [Chinese Optics Letters 9, 060201 (2011)

    Institute of Scientific and Technical Information of China (English)

    Jicheng Wang; Yueyuan Wang; Yueke Wang; Guangyu Fang; Shutian Liu

    2011-01-01

    This article "Measurements of total absolute collision cross section of ultracold Rb atom using magneto-optic and pure magnetic traps",which was published on Chinese Optics Letters (9,060201 (2011)) has been retracted at the request of the authors.Reason:The first author,Jicheng Wang,participated in a related research in Professor Kirk Madison's group in the Department of Physics & Astronomy at the University of British Columbia,Canada from September 2008 to February 2010.Some of the experimental data have not been authorized for publication,even though they have been consented to be used by Jicheng Wang in his own research.The authors apologize to Professor K.Madison for misunderstanding,and to Chinese Optics Letters and the readers of Chinese Optics Letters for any inconvenience this mistake may have caused.

  15. MAGNET

    CERN Multimedia

    B. Curé

    2012-01-01

      The magnet and its sub-systems were stopped at the beginning of the winter shutdown on 8th December 2011. The magnet was left without cooling during the cryogenics maintenance until 17th January 2012, when the cryoplant operation resumed. The magnet temperature reached 93 K. The vacuum pumping was maintained during this period. During this shutdown, the yearly maintenance was performed on the cryogenics, the vacuum pumps, the magnet control and safety systems, and the power converter and discharge lines. Several preventive actions led to the replacement of the electrovalve command coils, and the 20A DC power supplies of the magnet control system. The filters were cleaned on the demineralised water circuits. The oil of the diffusion pumps was changed. On the cryogenics, warm nitrogen at 343 K was circulated in the cold box to regenerate the filters and the heat exchangers. The coalescing filters have been replaced at the inlet of both the turbines and the lubricant trapping unit. The active cha...

  16. Helicity-dependent all-optical switching in hybrid metal-ferromagnet structures for ultrafast magnetic data storage

    Science.gov (United States)

    Cheng, Feng

    The emerging Big Data era demands the rapidly increasing need for speed and capacity of storing and processing information. Standalone magnetic recording devices, such as hard disk drives (HDDs), have always been playing a central role in modern data storage and continuously advancing. Recognizing the growing capacity gap between the demand and production, industry has pushed the bit areal density in HDDs to 900 Giga-bit/square-inch, a remarkable 450-million-fold increase since the invention of the first hard disk drive in 1956. However, the further development of HDD capacity is facing a pressing challenge, the so-called superparamagnetic effect, that leads to the loss of information when a single bit becomes too small to preserve the magnetization. This requires new magnetic recording technologies that can write more stable magnetic bits into hard magnetic materials. Recent research has shown that it is possible to use ultrafast laser pulses to switch the magnetization in certain types of magnetic thin films. Surprisingly, such a process does not require an externally applied magnetic field that always exists in conventional HDDs. Furthermore, the optically induced magnetization switching is extremely fast, up to sub-picosecond (10 -12 s) level, while with traditional recording method the deterministic switching does not take place shorter than 20 ps. It's worth noting that the direction of magnetization is related to the helicity of the incident laser pulses. Namely, the right-handed polarized laser pulses will generate magnetization pointing in one direction while left-handed polarized laser pulses generate magnetization pointing in the other direction. This so-called helicity-dependent all-optical switching (HD-AOS) phenomenon can be potentially used in the next-generation of magnetic storage systems. In this thesis, I explore the HD-AOS phenomenon in hybrid metal-ferromagnet structures, which consist of gold and Co/Pt multilayers. The experiment results show

  17. Trapping and manipulating single molecules of DNA

    Science.gov (United States)

    Shon, Min Ju

    This thesis presents the development and application of nanoscale techniques to trap and manipulate biomolecules, with a focus on DNA. These methods combine single-molecule microscopy and nano- and micro-fabrication to study biophysical properties of DNA and proteins. The Dimple Machine is a lab-on-a-chip device that can isolate and confine a small number of molecules from a bulk solution. It traps molecules in nanofabricated chambers, or "dimples", and the trapped molecules are then studied on a fluorescence microscope at the single-molecule level. The sampling of bulk solution by dimples is representative, reproducible, and automated, enabling highthroughput single-molecule experiments. The device was applied to study hybridization of oligonucleotides, particularly in the context of reaction thermodynamics and kinetics in nanoconfinement. The DNA Pulley is a system to study protein binding and the local mechanical properties of DNA. A molecule of DNA is tethered to a surface on one end, and a superparamagnetic bead is attached to the other. A magnet pulls the DNA taut, and a silicon nitride knife with a nanoscale blade scans the DNA along its contour. Information on the local properties of the DNA is extracted by tracking the bead with nanometer precision in a white-light microscope. The system can detect proteins bound to DNA and localize their recognition sites, as shown with a model protein, EcoRI restriction enzyme. Progress on the measurements of nano-mechanical properties of DNA is included.

  18. Hybrid magnetic amphiphilic composites based on carbon nanotube/nanofibers and layered silicates fragments as efficient adsorbent for ethynilestradiol.

    Science.gov (United States)

    Purceno, Aluir D; Teixeira, Ana Paula C; de Souza, Nubia Janaína; Fernandez-Outon, Luis E; Ardisson, José D; Lago, Rochel M

    2012-08-01

    In this work, hybrid magnetic amphiphilic composites were prepared by the catalytic growth of carbon nanotubes (CNTs) and nanofibers CNF on layered silicates fragments. SEM, TEM, Raman, XRD, Mössbauer, TG/DTA showed that CVD with CH(4) at 800°C produced CNF and magnetic Fe cores fixed on the surface of microfragments of silicates layers. Due to the amphiphilic character, the composites can be easily dispersed in water and efficiently adsorb hydrophobic contaminant molecules. For example, the composites showed remarkable adsorption capacities for the hormone ethinylestradiol, e.g. 2-4 mg m(-2), compared to ca. 0.1 mg m(-2) obtained for high surface area activated carbon and multiwall CNT. These results are discussed in terms of a high hydrophobic exposed surface area of the CNT and CNF fixed on the layered silicates fragments surface. Moreover, the composites can be easily removed from water by a simple magnetic separation process.

  19. Search For Trapped Antihydrogen

    CERN Document Server

    Andresen, Gorm B; Baquero-Ruiz, Marcelo; Bertsche, William; Bowe, Paul D; Bray, Crystal C; Butler, Eoin; Cesar, Claudio L; Chapman, Steven; Charlton, Michael; Fajans, Joel; Friesen, Tim; Fujiwara, Makoto C; Gill, David R; Hangst, Jeffrey S; Hardy, Walter N; Hayano, Ryugo S; Hayden, Michael E; Humphries, Andrew J; Hydomako, Richard; Jonsell, Svante; Jørgensen, Lars V; Kurchaninov, Lenoid; Lambo, Ricardo; Madsen, Niels; Menary, Scott; Nolan, Paul; Olchanski, Konstantin; Olin, Art; Povilus, Alexander; Pusa, Petteri; Robicheaux, Francis; Sarid, Eli; Nasr, Sarah Seif El; Silveira, Daniel M; So, Chukman; Storey, James W; Thompson, Robert I; van der Werf, Dirk P; Wilding, Dean; Wurtele, Jonathan S; Yamazaki, Yasunori

    2011-01-01

    We present the results of an experiment to search for trapped antihydrogen atoms with the ALPHA antihydrogen trap at the CERN Antiproton Decelerator. Sensitive diagnostics of the temperatures, sizes, and densities of the trapped antiproton and positron plasmas have been developed, which in turn permitted development of techniques to precisely and reproducibly control the initial experimental parameters. The use of a position-sensitive annihilation vertex detector, together with the capability of controllably quenching the superconducting magnetic minimum trap, enabled us to carry out a high-sensitivity and low-background search for trapped synthesised antihydrogen atoms. We aim to identify the annihilations of antihydrogen atoms held for at least 130 ms in the trap before being released over ~30 ms. After a three-week experimental run in 2009 involving mixing of 10^7 antiprotons with 1.3 10^9 positrons to produce 6 10^5 antihydrogen atoms, we have identified six antiproton annihilation events that are consist...

  20. Sol-gel-derived Hybrid Conductive Films for Electro magnetic Interference (EMI) Shielding

    Institute of Scientific and Technical Information of China (English)

    XIE Jiyuan; GUO Wenfeng; WANG Jianzhong

    2011-01-01

    The conductive nano-sized zinc particles were embedded in an insulating amorphous silica matrix, and the hybrid films were obtained by a sol-gel method. The stable hybrid sol solution was prepared by hydrolysis and condensation of Methyltrimethoxysilane (MTMS) with a one-step acidic catalyst process. Hybrid films were dip-coated on silicon wafer and cured at 120 ℃ for 60minutes. The structural characterization of hybrid films were investigated by means of attenuated total reflection infrared (ATR-IR) spectroscopy and X-ray diffraetion (XRD). The electrical properties of the films were examined with four-point probe. Hybrid films showed to be relatively dense, uniform and defect free. The conductivity of hybrid films was varied with the different contents of zinc nanoparticles and the thickness of the film. It was observed that there was the percolation threshold for the film's electrical properties.

  1. Jovian Plasmas Torus Interaction with Europa. Plasma Wake Structure and Effect of Inductive Magnetic Field: 3D Hybrid Kinetic Simulation

    Science.gov (United States)

    Lipatov, A. S.; Cooper, J F.; Paterson, W. R.; Sittler, E. C., Jr.; Hartle, R. E.; Simpson, David G.

    2013-01-01

    The hybrid kinetic model supports comprehensive simulation of the interaction between different spatial and energetic elements of the Europa moon-magnetosphere system with respect to a variable upstream magnetic field and flux or density distributions of plasma and energetic ions, electrons, and neutral atoms. This capability is critical for improving the interpretation of the existing Europa flyby measurements from the Galileo Orbiter mission, and for planning flyby and orbital measurements (including the surface and atmospheric compositions) for future missions. The simulations are based on recent models of the atmosphere of Europa (Cassidy et al., 2007; Shematovich et al., 2005). In contrast to previous approaches with MHD simulations, the hybrid model allows us to fully take into account the finite gyroradius effect and electron pressure, and to correctly estimate the ion velocity distribution and the fluxes along the magnetic field (assuming an initial Maxwellian velocity distribution for upstream background ions). Photoionization, electron-impact ionization, charge exchange and collisions between the ions and neutrals are also included in our model. We consider the models with Oþ þ and Sþ þ background plasma, and various betas for background ions and electrons, and pickup electrons. The majority of O2 atmosphere is thermal with an extended non-thermal population (Cassidy et al., 2007). In this paper, we discuss two tasks: (1) the plasma wake structure dependence on the parameters of the upstream plasma and Europa's atmosphere (model I, cases (a) and (b) with a homogeneous Jovian magnetosphere field, an inductive magnetic dipole and high oceanic shell conductivity); and (2) estimation of the possible effect of an induced magnetic field arising from oceanic shell conductivity. This effect was estimated based on the difference between the observed and modeled magnetic fields (model II, case (c) with an inhomogeneous Jovian magnetosphere field, an inductive

  2. Microchip-Based Trapped-Atom Clocks

    CERN Document Server

    Vuletic, Vladan; Schleier-Smith, Monika H

    2011-01-01

    This is a chapter of a recently published book entitled Atom Chips, edited by Jakob Reichel and Vladan Vuletic. The contents of this chapter include: Basic Principles; Atomic-Fountain versus Trapped-Atom Clocks; Optical-Transition Clocks versus Microwave Clocks; Clocks with Magnetically Trapped Atoms--Fundamental Limits and Experimental Demonstrations; Readout in Trapped-Atom Clocks; and Spin Squeezing.

  3. Magnetic Flux-Trapping of Anisotropic-Grown Y-Ba-Cu-O Bulk Superconductors during and after Pulsed-Field Magnetizing Processes

    Science.gov (United States)

    Oka, T.; Yamada, Y.; Horiuchi, T.; Ogawa, J.; Fukui, S.; Sato, T.; Yokoyama, K.; Langer, M.

    2014-05-01

    The magnetic flux penetration into the melt-textured Y-Ba-Cu-O high temperature superconducting bulk magnets were precisely evaluated during and after the pulsed field magnetization processes operated at 30 K. The bulk magnets were carefully fabricated by the cold seeding method with use of a single and a pair of seed crystals composed of the Nd-Ba-Cu-O thin films. These seed crystals were put on the top surfaces of the precursors to let the large grains grow during the heat treatments. We observed the flux penetrations which occurred in the lower applied-field regions at around 3.1 T for the samples bearing the twin seeds than those of the single-seeded crystals at around 3.8 T. This means that the magnetic fluxes are capable of invading into the twin-seeded samples more easily than the single-seeds. It suggests that the anisotropic grain growths of parallel and normal to the rows of seed crystals affects the variations of Jc values with different distributions of the pinning centers, results in the preferential paths for the invading magnetic fluxes.

  4. A Novel Integrated Magnetic Structure Based DC/DC Converter for Hybrid Battery/Ultracapacitor Energy Storage Systems

    Energy Technology Data Exchange (ETDEWEB)

    Onar, Omer C [ORNL

    2012-01-01

    This manuscript focuses on a novel actively controlled hybrid magnetic battery/ultracapacitor based energy storage system (ESS) for vehicular propulsion systems. A stand-alone battery system might not be sufficient to satisfy peak power demand and transient load variations in hybrid and plug-in hybrid electric vehicles (HEV, PHEV). Active battery/ultracapacitor hybrid ESS provides a better solution in terms of efficient power management and control flexibility. Moreover, the voltage of the battery pack can be selected to be different than that of the ultracapacitor, which will result in flexibility of design as well as cost and size reduction of the battery pack. In addition, the ultracapacitor bank can supply or recapture a large burst of power and it can be used with high C-rates. Hence, the battery is not subjected to supply peak and sharp power variations, and the stress on the battery will be reduced and the battery lifetime would be increased. Utilizing ultracapacitor results in effective capturing of the braking energy, especially in sudden braking conditions.

  5. Hybrid metal-dielectric ring resonators for homogenizable optical metamaterials with strong magnetic response at short wavelengths down to the ultraviolet range.

    Science.gov (United States)

    Tang, Jianwei; He, Sailing

    2013-10-07

    We derive an analytical LC model from Maxwell's equations for the magnetic resonance of subwavelength ring resonators. Using the LC model, we revisit the scaling of split-ring resonators. Inspired by the LC model, we propose a hybrid metal-dielectric ring resonator mainly composed of high index dielectric material (e.g., TiO₂) with some gaps filled with metal (e.g., Ag). The saturation frequency of magnetic response for the hybrid metal-dielectric ring resonator is much higher (up to the ultraviolet range) than that for split-ring resonators, and can be controlled by the metal fraction in the ring. The hybrid metal-dielectric ring resonator can also overcome the homogenization problem of all-dielectric magnetic resonators, and therefore can form homogenizable magnetic metamaterials at short wavelengths down to the ultraviolet range.

  6. Parametric decay instability near the upper hybrid resonance in magnetically confined fusion plasmas

    DEFF Research Database (Denmark)

    Hansen, Søren Kjer; Nielsen, Stefan Kragh; Salewski, Mirko

    2017-01-01

    In this paper we investigate parametric decay of an electromagnetic pump wave into two electrostatic daughter waves, particularly an X-mode pump wave decaying into a warm upper hybrid wave (a limit of an electron Bernstein wave) and a warm lower hybrid wave. We describe the general theory...

  7. Magnetic particle-based sandwich sensor with DNA-modified carbon nanotubes as recognition elements for detection of DNA hybridization.

    Science.gov (United States)

    Hu, Po; Huang, Cheng Zhi; Li, Yuan Fang; Ling, Jian; Liu, Yu Ling; Fei, Liang Run; Xie, Jian Ping

    2008-03-01

    In this contribution, we design a visual sensor for DNA hybridization with DNA probe-modified magnetic particles (MPs) and multiwalled carbon nanotubes (MWNTs) without involving a visual recognition element such as fluorescent/chemiluminescent reagents. It was found that DNA probe-modified MWNTs, which could be dispersed in aqueous medium and have strong light scattering signals under the excitation of a light beam in the UV-vis region, could connect with DNA probe-modified MPs together in the presence of perfectly complementary target DNA and form a sandwich structure. In a magnetic field, the formed MP-MWNT species can easily be removed from the solution, resulting in a decrease of light scattering signals. Thus, a magnetic particle-based sandwich sensor could be developed to detect DNA hybridization by measuring the light scattering signals with DNA-modified MWNTs as recognition elements. Experiments showed that the DNA-modified MPs sensor could be reused at least 17 times and was stable for more than 6 months.

  8. Research on the filtering characteristic of single phase series hybrid active power filter based on fundamental magnetic flux compensation

    Science.gov (United States)

    Tian, Jun; Chen, Qiaofu; Zhang, Yuqi

    2012-12-01

    In this article, the PWM inverter works as a controlled fundamental current source in the single phase series hybrid active power filter (APF) based on fundamental magnetic flux compensation (FMFC). The series transformer can exhibit the self-impedance of primary winding to harmonic current, which forces harmonic current to flow into passive power filter. With the influence of harmonic current, the voltage of primary winding of transformer is a harmonic voltage, which makes the inverter output currents have a certain harmonic component, and it degrades the filtering characteristics. On the basis of PWM inverter, the mathematical model of series hybrid APF is established, and the filtering characteristics of single phase APF are analysed in detail. Three methods are gained to improve filtering characteristics: reasonably designing the inverter output filter inductance, increasing series transformer ratio and adopting voltage feed-forward control. Experimental results show that the proposed APF has greater validity.

  9. Estimation of Curie temperature of manganite-based materials for magnetic refrigeration application using hybrid gravitational based support vector regression

    Science.gov (United States)

    Owolabi, Taoreed O.; Akande, Kabiru O.; Olatunji, Sunday O.; Alqahtani, Abdullah; Aldhafferi, Nahier

    2016-10-01

    Magnetic refrigeration (MR) technology stands a good chance of replacing the conventional gas compression system (CGCS) of refrigeration due to its unique features such as high efficiency, low cost as well as being environmental friendly. Its operation involves the use of magnetocaloric effect (MCE) of a magnetic material caused by application of magnetic field. Manganite-based material demonstrates maximum MCE at its magnetic ordering temperature known as Curie temperature (TC). Consequently, manganite-based material with TC around room temperature is essentially desired for effective utilization of this technology. The TC of manganite-based materials can be adequately altered to a desired value through doping with appropriate foreign materials. In order to determine a manganite with TC around room temperature and to circumvent experimental challenges therein, this work proposes a model that can effectively estimates the TC of manganite-based material doped with different materials with the aid of support vector regression (SVR) hybridized with gravitational search algorithm (GSA). Implementation of GSA algorithm ensures optimum selection of SVR hyper-parameters for improved performance of the developed model using lattice distortions as the descriptors. The result of the developed model is promising and agrees excellently with the experimental results. The outstanding estimates of the proposed model suggest its potential in promoting room temperature magnetic refrigeration through quick estimation of the effect of dopants on TC so as to obtain manganite that works well around the room temperature.

  10. Estimation of Curie temperature of manganite-based materials for magnetic refrigeration application using hybrid gravitational based support vector regression

    Directory of Open Access Journals (Sweden)

    Taoreed O. Owolabi

    2016-10-01

    Full Text Available Magnetic refrigeration (MR technology stands a good chance of replacing the conventional gas compression system (CGCS of refrigeration due to its unique features such as high efficiency, low cost as well as being environmental friendly. Its operation involves the use of magnetocaloric effect (MCE of a magnetic material caused by application of magnetic field. Manganite-based material demonstrates maximum MCE at its magnetic ordering temperature known as Curie temperature (TC. Consequently, manganite-based material with TC around room temperature is essentially desired for effective utilization of this technology. The TC of manganite-based materials can be adequately altered to a desired value through doping with appropriate foreign materials. In order to determine a manganite with TC around room temperature and to circumvent experimental challenges therein, this work proposes a model that can effectively estimates the TC of manganite-based material doped with different materials with the aid of support vector regression (SVR hybridized with gravitational search algorithm (GSA. Implementation of GSA algorithm ensures optimum selection of SVR hyper-parameters for improved performance of the developed model using lattice distortions as the descriptors. The result of the developed model is promising and agrees excellently with the experimental results. The outstanding estimates of the proposed model suggest its potential in promoting room temperature magnetic refrigeration through quick estimation of the effect of dopants on TC so as to obtain manganite that works well around the room temperature.

  11. Status and Outlook of CHIP-TRAP: the Central Michigan University High Precision Penning Trap

    CERN Document Server

    Redshaw, Matthew; Hawks, Paul; Gamage, Nadeesha D; Hunt, Curtis; Kandegedara, Rathnayake M E B; Ratnayake, Ishara S; Sharp, Lance

    2015-01-01

    At Central Michigan University we are developing a high-precision Penning trap mass spectrometer (CHIP-TRAP)that will focus on measurements with long-lived radioactive isotopes. CHIP-TRAP will consist of a pair of hyperbolic precision-measurement Penning traps, and a cylindrical capture/?filter trap in a 12 T magnetic field. Ions will be produced by external ion sources, including a laser ablation source, and transported to the capture trap at low energies enabling ions of a given m=q ratio to be selected via their time-of-flight. In the capture trap, contaminant ions will be removed with a mass-selective rf dipole excitation and the ion of interest will be transported to the measurement traps. A phase-sensitive image charge detection technique will be used for simultaneous cyclotron frequency measurements on single ions in the two precision traps, resulting in a reduction in statistical uncertainty due to magnetic field fluctuations.

  12. Two Contemporary Problems in Magnetized Plasmas: the ion-ion hybrid resonator and MHD stability in a snowflake divertor

    Energy Technology Data Exchange (ETDEWEB)

    Farmer, William Anthony [Univ. of California, Los Angeles, CA (United States)

    2014-01-01

    The rst part of the dissertation investigates the e ects of multiple-ions on the propagation of shear Alfv en waves. It is shown that the presence of a second ion-species allows for the formation of an ion-ion hybrid resonator in the presence of a magnetic well. A fullwave description is shown to explain the measured eigenfrequencies and spatial form of the resonator modes identi ed in experiments in the Large Plasma Device (LAPD) at UCLA. However, it is determined that neither electron collisions or radial convection of the mode due to coupling to either the compressional or ion-Bernstein wave can explain the observed dissipation.

  13. Redox-active organometallics: magnetic and electronic couplings through carbon-silicon hybrid molecular connectors.

    Science.gov (United States)

    Hamon, Paul; Justaud, Frederic; Cador, Olivier; Hapiot, Philippe; Rigaut, Stéphane; Toupet, Loïc; Ouahab, Lahcène; Stueger, Harald; Hamon, Jean-René; Lapinte, Claude

    2008-12-24

    Treatment of the triflate complex Cp*(dppe)FeOTf [12; Cp* = eta(5)-C(5)(CH(3))(5), dppe = 1,2-bis(diphenylphosphino)ethane, OTf = CF(3)SO(3)] with an excess of HC[triple bond]C-(Si(CH(3))(2))(x)-C[triple bond]CH (x = 2-4) in diethyl ether provides the binuclear bis(vinylidene) derivatives [Cp*(dppe)Fe=C=CH(Si(CH(3))(2))(x)CH=C=Fe(dppe)Cp*][OTf](2) (x = 2, 13; x = 3, 14; x = 4, 15), which were isolated as ochre solids and rapidly characterized by FT-IR, (1)H, (31)P, and (13)C NMR spectroscopies. The complexes 13-15 were reacted with potassium tert-butoxide to afford the bis(alkynediyl) complexes [Cp*(dppe)Fe-C[triple bond]C(Si(CH(3))(2))(x)C[triple bond]C-Fe(dppe)Cp*] (x = 2, 1; x = 3, 2; x = 4, 3), which were isolated as orange powders in yields ranging from 76 to 91%. The IR, cyclic voltammetry, and UV-vis data obtained for 1-3 and the X-ray crystal structures determined for 1 and 3 reveal the importance of the sigma-pi conjugation (hyperconjugation) between the Si-Si sigma bond and the adjacent C[triple bond]C pi-symmetric orbitals in the description of the electronic structure of the ground state of these complexes. When reacted at low temperature with 2 equiv of [(C(5)H(5))(2)Fe]X or AgX [X = BPh(4), B(3,5-(CF(3))(2)C(6)H(3))(4))], compounds 1-3 provide 1[X](2), 2[X](2), and 3[X](2), which can be isolated and stored below -20 degrees C. EPR spectroscopy and magnetization measurements established that the superexchange interaction propagates through the Si-Si bonds (J = -0.97(2) cm(-1) for 3[X](2)). UV-vis-near-IR spectra were obtained with an optically transparent thin-layer electrosynthetic (OTTLE) cell for 1-3[OTf](n) (n = 0-2). A band with a maximum that increases from 6400 cm(-1) (1[OTf]) to 8500 cm(-1) (3[OTf]) observed for the mixed-valence species was ascribed to intervalence charge transfer evidencing photodriven electron transfer through the carbon-silicon hybrid connectors with H(ab) parameters ranging from 64 to 285 cm(-1).

  14. 新型混合径向磁轴承结构及其磁力特性%Structure and magnetic characteristics of novel hybrid radial magnetic bearing

    Institute of Scientific and Technical Information of China (English)

    陈君辉; 杨逢瑜; 聂朝瑞; 李正贵; 杨军; 王鹏雁

    2012-01-01

    Aimed at some problems in the permanent magnetic circuit of available magnetic radial bearings with permanent magnet bias such as small magnetic force, low magnetic flux density, and lack of self-stabilization. A new hybrid radial magnetic bearing structure for vertical axial flow pump was proposed. The nonlinear model and linearization equation of the bearing capacity of the new hybrid radial magnetic bearing were established by using current molecular method and virtual displacement theorem. It was found by a-nalysis that with this permanent magnetic suspension bearing, its self-stabilization would exhibit in some radial degrees of freedom and the total displacement negative stiffness of the system could be reduced. The investigation result showed that the air gap flux density was greatly improved with the new hybrid magnetic bearing when Halbach array structure was used. Current stiffness and displacement rigidity were closely related to initial current and initial gap at the equilibrium position. Around the equilibrium position, the variation of current stiffness and displacement rigidity was linear. With the increase of air gap, its linearity was well kept. With the decrease of air gap, however, a certain nonlinear characteristics exhibited.%针对当前永磁偏置径向磁轴承的永磁磁路的磁通密度低,磁力小,缺乏自稳定的问题,提出一种应用于立式轴流泵的新型混合径向磁轴承结构.应用分子电流法及虚位移定理建立新型混合径向磁轴承承载力的非线性模型及其线性化方程,分析得出新型径向混合磁悬浮轴承在径向某个自由度上具有自稳定的特点,且水磁轴承可以减小系统总的位移负刚度.研究结果表明,采用Halbach阵列结构后,混合磁轴承气隙的磁通密得到很大提高.电流刚度和位移刚度与平衡点的初始电流及初始间隙密切相关,在平衡位置附近电流刚度和位移刚度呈线性变化,当气隙增大时仍保

  15. 68Ga-TRAP-(RGD)3 Hybrid Imaging for the In Vivo Monitoring of αvß3-Integrin Expression as Biomarker of Anti-Angiogenic Therapy Effects in Experimental Breast Cancer

    Science.gov (United States)

    Kazmierczak, Philipp M.; Todica, Andrei; Gildehaus, Franz-Josef; Hirner-Eppeneder, Heidrun; Brendel, Matthias; Eschbach, Ralf S.; Hellmann, Magdalena; Nikolaou, Konstantin; Reiser, Maximilian F.; Wester, Hans-Jürgen; Kropf, Saskia; Rominger, Axel; Cyran, Clemens C.

    2016-01-01

    Objectives To investigate 68Ga-TRAP-(RGD)3 hybrid imaging for the in vivo monitoring of αvß3-integrin expression as biomarker of anti-angiogenic therapy effects in experimental breast cancer. Materials and Methods Human breast cancer (MDA-MB-231) xenografts were implanted orthotopically into the mammary fat pads of n = 25 SCID mice. Transmission/emission scans (53 min to 90 min after i.v. injection of 20 MBq 68Ga-TRAP-(RGD)3) were performed on a dedicated small animal PET before (day 0, baseline) and after (day 7, follow-up) a 1-week therapy with the VEGF antibody bevacizumab or placebo (imaging cohort n = 13; therapy n = 7, control n = 6). The target-to-background ratio (TBR, VOImaxtumor/VOImeanmuscle) served as semiquantitative measure of tumor radiotracer uptake. Unenhanced CT data sets were subsequently acquired for anatomic coregistration and morphology-based tumor response assessments (CT volumetry). The imaging results were validated by multiparametric ex vivo immunohistochemistry (αvß3-integrin, microvascular density–CD31, proliferation–Ki-67, apoptosis–TUNEL) conducted in a dedicated immunohistochemistry cohort (n = 12). Results 68Ga-TRAP-(RGD)3 binding was significantly reduced under VEGF inhibition and decreased in all bevacizumab-treated animals (ΔTBRfollow-up/baseline: therapy -1.07±0.83, control +0.32±1.01, p = 0.022). No intergroup difference in tumor volume development between day 0 and day 7 was observed (Δvolumetherapy 134±77 μL, Δvolumecontrol 132±56 μL, p = 1.000). Immunohistochemistry revealed a significant reduction of αvß3-integrin expression (308±135 vs. 635±325, p = 0.03), microvascular density (CD31, 168±108 vs. 432±70, p = 0.002), proliferation (Ki-67, 5,195±1,002 vs. 7,574±418, p = 0.004) and significantly higher apoptosis (TUNEL, 14,432±1,974 vs. 3,776±1,378, p = 0.002) in the therapy compared to the control group. Conclusions 68Ga-TRAP-(RGD)3 hybrid imaging allows for the in vivo assessment of αvß3

  16. Coherence in Microchip Traps

    CERN Document Server

    Treutlein, P; Steinmetz, T; Hänsch, T W; Reichel, J; Treutlein, Philipp; Hommelhoff, Peter; Steinmetz, Tilo; H\\"ansch, Theodor W.; Reichel, Jakob

    2003-01-01

    We report the coherent manipulation of internal states of neutral atoms in a magnetic microchip trap. Coherence lifetimes exceeding 1 s are observed with atoms at distances of $4-130 \\mu$m from the microchip surface. The coherence lifetime in the microtrap is independent of atom-surface distance and agrees well with the results of similar measurements in macroscopic magnetic traps. Due to the absence of surface-induced decoherence, a miniaturized atomic clock with a relative stability in the $10^{-13}$ range can be realized. For applications in quantum information processing, we propose to use microwave near-fields in the proximity of chip wires to create potentials that depend on the internal state of the atoms.

  17. Multi-responsive hybrid particles: thermo-, pH-, photo-, and magneto-responsive magnetic hydrogel cores with gold nanorod optical triggers

    Science.gov (United States)

    Rittikulsittichai, Supparesk; Kolhatkar, Arati G.; Sarangi, Subhasis; Vorontsova, Maria A.; Vekilov, Peter G.; Brazdeikis, Audrius; Randall Lee, T.

    2016-06-01

    The research strategy described in this manuscript harnesses the attractive properties of hydrogels, gold nanorods (Aurods), and magnetic nanoparticles (MNPs) by synthesizing one unique multi-responsive nanostructure. This novel hybrid structure consists of silica-coated magnetic particles encapsulated within a thermo-responsive P(NIPAM-co-AA) hydrogel network on which Aurods are assembled. Furthermore, this research demonstrates that these composite particles respond to several forms of external stimuli (temperature, pH, light, and/or applied magnetic field) owing to their specific architecture. Exposure of the hybrid particles to external stimuli led to a systematic and reversible variation in the hydrodynamic diameter (swelling-deswelling) and thus in the optical properties of the hybrid particles (red-shifting of the plasmon band). Such stimuli-responsive volume changes can be effectively exploited in drug-delivery applications.The research strategy described in this manuscript harnesses the attractive properties of hydrogels, gold nanorods (Aurods), and magnetic nanoparticles (MNPs) by synthesizing one unique multi-responsive nanostructure. This novel hybrid structure consists of silica-coated magnetic particles encapsulated within a thermo-responsive P(NIPAM-co-AA) hydrogel network on which Aurods are assembled. Furthermore, this research demonstrates that these composite particles respond to several forms of external stimuli (temperature, pH, light, and/or applied magnetic field) owing to their specific architecture. Exposure of the hybrid particles to external stimuli led to a systematic and reversible variation in the hydrodynamic diameter (swelling-deswelling) and thus in the optical properties of the hybrid particles (red-shifting of the plasmon band). Such stimuli-responsive volume changes can be effectively exploited in drug-delivery applications. Electronic supplementary information (ESI) available: Contains detailed information about the synthesis of

  18. Structural and magnetic properties of TlTF{sub 3} (T=Fe, Co and Ni) by hybrid functional theory

    Energy Technology Data Exchange (ETDEWEB)

    Zeb, Raham [Center for Computational Materials Science, University of Malakand, Chakdara, Dir (Lower) (Pakistan); Department of Physics, University of Malakand, Chakdara, Dir (Lower) (Pakistan); Ali, Zahid, E-mail: zahidf82@gmail.com [Center for Computational Materials Science, University of Malakand, Chakdara, Dir (Lower) (Pakistan); Department of Physics, University of Malakand, Chakdara, Dir (Lower) (Pakistan); Ahmad, Iftikhar; Khan, Imad [Center for Computational Materials Science, University of Malakand, Chakdara, Dir (Lower) (Pakistan); Department of Physics, University of Malakand, Chakdara, Dir (Lower) (Pakistan)

    2015-08-15

    DFT studies are performed to investigate the structural, mechanical and magneto-electronic properties of the TlTF{sub 3} (T=Fe, Co and Ni) perovskites for the first time using GGA, GGA+U and hybrid density functional theory (HF). Our calculations show that HF give better results than GGA and GGA+U and more consistent with the experiments. The comparison of the lattice constants calculated by HF with experiments shows a maximum underestimation less than 0.2%. The chemical bonding between different ions in these compounds is explained on the bases of electronic clouds, which reveals that in TlFeF{sub 3}, Fe has more ionic character with F than the rest. The mechanical properties explain the hardness of these compounds and show that TlFeF{sub 3} is more ductile. Spin-dependent electronic band profiles show that TlFeF{sub 3} and TlCoF{sub 3} are metallic, whereas TlNiF{sub 3} is pseudo direct wide bandgap semiconductor. The stable magnetic phase optimizations and the calculated magnetic susceptibility confirm that TlFeF{sub 3} and TlNiF{sub 3} are ferromagnetic whereas TlCoF{sub 3} is anti-ferromagnetic material. - Highlights: • TlTF{sub 3} (T=Fe, Co and Ni) perovskites are investigated theoretically by hybrid density functional theory. • Mechanical properties explain the hardness of these compounds and show that TlFeF{sub 3} is more ductile. • The bandgap calculations show that TlFeF{sub 3} and TlCoF{sub 3} are metallic, whereas TlNiF{sub 3} is a wide bandgap semiconductor. • Magnetic optimizations and magnetic susceptibility confirm that TlFeF{sub 3} and TlNiF{sub 3} are ferromagnetic whereas TlCoF{sub 3} is anti-ferromagnetic material.

  19. Trapped field properties of a Y–Ba–Cu–O bulk by pulsed field magnetization using a split coil inserted by iron yokes with various geometries and electromagnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, K., E-mail: t2216017@iwate-u.ac.jp [Department of Physical Science and Materials Engineering, Faculty of Science and Engineering, Iwate University, 4-3-5 Ueda, Morioka 020-8551 (Japan); Ainslie, M.D. [Bulk Superconductivity Group, Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ (United Kingdom); Fujishiro, H.; Naito, T. [Department of Physical Science and Materials Engineering, Faculty of Science and Engineering, Iwate University, 4-3-5 Ueda, Morioka 020-8551 (Japan); Shi, Y-H.; Cardwell, D.A. [Bulk Superconductivity Group, Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ (United Kingdom)

    2017-05-15

    Highlights: • The trapped field characteristics of a standard Y–Ba–Cu–O bulk magnetized by PFM was investigated using a split coil with three kinds of iron yokes inserted in the bores of coil,both experimentally and numerically. • Numerical results encourage better understanding of the role of yoke, including the typical behavior of the magnetic flux, such as a flux jump during PFM. • A higher saturation magnetic flux density of the yoke material was effective to reduce flux flow in the descending stage of the pulsed field. • A conductivity of the yoke material also acts to reduce the velocity of the flux intruding the bulk because of eddy currents that flow in the yoke that oppose the magnetization, which reduces the temperature rise in the bulk. - Abstract: We have investigated, both experimentally and numerically, the trapped field characteristics of a standard Y–Ba–Cu–O bulk of 30 mm in diameter and 14 mm in thickness magnetized by pulsed field magnetization (PFM) using a split coil, in which three kinds of iron yoke are inserted in the bore of the coil: soft iron with a flat surface, soft iron with a taper, and permendur (50Fe + 50Co alloy) with a flat surface. The highest trapped field, B{sub Tmax}, of 2.93 T was achieved at 40 K in the case of the permendur yoke, which was slightly higher than that obtained for the flat soft iron or the tapered soft iron yokes, and was much higher than 2.20 T in the case without the yoke. The insertion effect of the yoke on the trapped field characteristics was also investigated using numerical simulations. The results suggest that the saturation magnetic flux density, B{sub sat}, of the yoke acts to reduce the flux flow due to its hysteretic magnetization curve and the higher electrical conductivity, σ, of the yoke material also acts to suppress the flux increase rate. A flux jump (or flux leap) can be reproduced in the ascending stage of PFM using numerical simulation, using an assumption of relatively

  20. Modified Penning-Malmberg Trap for Storing Antiprotons

    Science.gov (United States)

    Sims, William H.; Martin, James; Lewis, Raymond

    2005-01-01

    A modified Penning-Malmberg trap that could store a small cloud of antiprotons for a relatively long time (weeks) has been developed. This trap is intended for use in research on the feasibility of contemplated future matter/antimatter-annihilation systems as propulsion sources for spacecraft on long missions. This trap is also of interest in its own right as a means of storing and manipulating antiprotons for terrestrial scientific experimentation. The use of Penning-Malmberg traps to store antiprotons is not new. What is new here is the modified trap design, which utilizes state-of-the-art radiofrequency (RF) techniques, including ones that, heretofore, have been used in radio-communication applications but not in iontrap applications. A basic Penning-Malmberg trap includes an evacuated round tube that contains or is surrounded by three or more collinear tube electrodes. A steady axial magnetic field that reaches a maximum at the geometric center of the tube is applied by an external source, and DC bias voltages that give rise to an electrostatic potential that reaches a minimum at the center are applied to the electrodes. The combination of electric and magnetic fields confines the charged particles (ions or electrons) for which it was designed to a prolate spheroidal central region. However, geometric misalignments and the diffusive cooling process prevent the steady fields of a basic Penning- Malmberg trap from confining the particles indefinitely. In the modified Penning-Malmberg trap, the loss of antiprotons is reduced or eliminated by use of a "rotating-wall" RF stabilization scheme that also heats the antiproton cloud to minimize loss by matter/antimatter annihilation. The scheme involves the superposition of a quadrupole electric field that rotates about the cylindrical axis at a suitably chosen radio frequency. The modified Penning-Malmberg trap (see Figure 1) includes several collinear sets of electrodes inside a tubular vacuum chamber. Each set