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Sample records for spin valves highly

  1. High frequency spin torque oscillators with composite free layer spin valve

    International Nuclear Information System (INIS)

    Natarajan, Kanimozhi; Arumugam, Brinda; Rajamani, Amuda

    2016-01-01

    We report the oscillations of magnetic spin components in a composite free layer spin valve. The associated Landau–Lifshitz–Gilbert–Slonczewski (LLGS) equation is studied by stereographically projecting the spin on to a complex plane and the spin components were found. A fourth order Runge–Kutta numerical integration on LLGS equation also confirms the similar trajectories of the spin components. This study establishes the possibility of a Spin Torque Oscillator in a composite free layer spin valve, where the exchange coupling is ferromagnetic in nature. In-plane and out-of-plane precessional modes of magnetization oscillations were found in zero applied magnetic field and the frequencies of the oscillations were calculated from Fast Fourier Transform of the components of magnetization. Behavior of Power Spectral Density for a range of current density is studied. Finally our analysis shows the occurrence of highest frequency 150 GHz, which is in the second harmonics for the specific choice of system parameters.

  2. High frequency spin torque oscillators with composite free layer spin valve

    Energy Technology Data Exchange (ETDEWEB)

    Natarajan, Kanimozhi; Arumugam, Brinda; Rajamani, Amuda

    2016-07-15

    We report the oscillations of magnetic spin components in a composite free layer spin valve. The associated Landau–Lifshitz–Gilbert–Slonczewski (LLGS) equation is studied by stereographically projecting the spin on to a complex plane and the spin components were found. A fourth order Runge–Kutta numerical integration on LLGS equation also confirms the similar trajectories of the spin components. This study establishes the possibility of a Spin Torque Oscillator in a composite free layer spin valve, where the exchange coupling is ferromagnetic in nature. In-plane and out-of-plane precessional modes of magnetization oscillations were found in zero applied magnetic field and the frequencies of the oscillations were calculated from Fast Fourier Transform of the components of magnetization. Behavior of Power Spectral Density for a range of current density is studied. Finally our analysis shows the occurrence of highest frequency 150 GHz, which is in the second harmonics for the specific choice of system parameters.

  3. Spin transport at high temperatures in epitaxial Heusler alloy/n-GaAs lateral spin valves

    Science.gov (United States)

    Peterson, Timothy A.; Christie, Kevin D.; Patel, Sahil J.; Crowell, Paul A.; Palmstrøm, Chris J.

    2015-03-01

    We report on electrical injection and detection of spin accumulation in ferromagnet/ n-GaAs lateral spin-valve devices, observed up to and above room temperature. The ferromagnet in these measurements is the Heusler alloy Co2FeSi, and the semiconductor channel is GaAs doped at 3 ×1016 cm-3. The spin signal is enhanced by operating the detection contact under forward bias. The enhancement originates from drift effects at low-temperatures and an increase of the detection efficiency at all temperatures. The detector bias dependence of the observed spin-valve signal is interpreted by taking into account the quantum well (QW) which forms in the degenerately doped region immediately behind the Schottky tunnel barrier. In particular, we believe the QW is responsible for the minority spin accumulation (majority spin current) under large forward bias. The spin diffusion length and lifetime are determined by measuring the separation dependence of the non-local spin valve signal in a family of devices patterned by electron beam lithography. A spin diffusion length of 700 nm and lifetime of 46 picoseconds are found at a temperature of 295 K. This work was supported by the NSF under DMR-1104951, the NSF MRSEC program and C-SPIN, a SRC STARNET center sponsored by MARCO and DARPA.

  4. Large Magnetoresistance at High Bias Voltage in Double-layer Organic Spin Valves

    Science.gov (United States)

    Subedi, R. C.; Liang, S. H.; Geng, R.; Zhang, Q. T.; Lou, L.; Wang, J.; Han, X. F.; Nguyen, T. D.

    We report studies of magnetoresistance (MR) in double-layer organic spin valves (DOSV) using tris (8-hydroxyquinolinato) aluminum (Alq3) spacers. The device exhibits three distinct resistance levels depending on the relative magnetizations of the ferromagnetic electrodes. We observed a much weaker bias voltage dependence of MR in the device compared to that in the conventional organic spin valve (OSV). The MR magnitude reduces by the factor of two at 0.7 V bias voltage in the DOSV compared to 0.02 V in the conventional OSV. Remarkably, the MR magnitude reaches 0.3% at 6 V bias in the DOSVs, the largest MR response ever reported in OSVs at this bias. Our finding may have a significant impact on achieving high efficient bipolar OSVs strictly performed at high voltages. University of Georgia start-up fund, Ministry of Education, Singapore, National Natural Science Foundation of China.

  5. FY1995 study of high density near-contact magnetic recording using spin valve head; 1995 nendo spin valve head ni yoru chokomitsudo near contact jiki kiroku no kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    Development of high performance spin valves formed by amorphous magnetic layer and head-medium interface with nano-thickness molecular film for realizing an ultra-high density of 20 Gbit/in{sup 2} using contact recording. The giant magnetoresistance effect was investigated for spin valves using very thin amorphous magnetic layer. In amorphous-CoFeB/Cu/ Co spin valves, the maximum MR ratio of 6% was achieved at the thickness of the amorphous layer of 2 nm. The spin valves with the amorphous layer exhibit very good thermal stability. Design guideline for molecularly thin lubricant was established using newly derived lubrication equation considering lubricant porosity. Novel method for accurately measuring surface force due to molecularly thin lubricant was developed by using Michelson interferometry to detect cantilever displacement, which enabled two-dimensional transient force measurement. (NEDO)

  6. Spin Switching via Quantum Dot Spin Valves

    Science.gov (United States)

    Gergs, N. M.; Bender, S. A.; Duine, R. A.; Schuricht, D.

    2018-01-01

    We develop a theory for spin transport and magnetization dynamics in a quantum dot spin valve, i.e., two magnetic reservoirs coupled to a quantum dot. Our theory is able to take into account effects of strong correlations. We demonstrate that, as a result of these strong correlations, the dot gate voltage enables control over the current-induced torques on the magnets and, in particular, enables voltage-controlled magnetic switching. The electrical resistance of the structure can be used to read out the magnetic state. Our model may be realized by a number of experimental systems, including magnetic scanning-tunneling microscope tips and artificial quantum dot systems.

  7. Interlayer quality dependent graphene spin valve

    International Nuclear Information System (INIS)

    Iqbal, Muhammad Zahir; Hussain, Ghulam; Siddique, Salma; Iqbal, Muhammad Waqas; Murtaza, Ghulam; Ramay, Shahid Mahmood

    2017-01-01

    It is possible to utilize the new class of materials for emerging two-dimensional (2D) spintronic applications. Here, the role of defects in the graphene interlayer and its influence on the spin valve signal is reported. The emergence of D peak in Raman spectrum reveals defects in the graphene layer. The linear I-V curve for defective and non-defective graphene samples indicate the ohmic nature of NiFe and graphene contact. A non-uniform magnetoresistive effect with a bump is persistently observed for defective graphene device at various temperatures, while a smooth and symmetric signal is detected for non-defective graphene spin valve. Parallel and antiparallel alignments of magnetization of magnetic materials shows low and high resistance states, respectively. The magnetoresistance (MR) ratio for defective graphene NiFe/graphene/NiFe spin valve is measured to be ~0.16% at 300 K which progresses to ~0.39% for non-defective graphene device at the same temperature. Similarly at 4.2 K the MR ratios are reported to be ~0.41% and ~0.78% for defective and non-defective graphene devices, respectively. Our investigation provides an evidence for relatively better response of the spin valve signal with high quality graphene interlayer.

  8. Interlayer quality dependent graphene spin valve

    Energy Technology Data Exchange (ETDEWEB)

    Iqbal, Muhammad Zahir, E-mail: zahir.upc@gmail.com [Faculty of Engineering Sciences, GIK Institute of Engineering Sciences and Technology, Topi, Khyber Pakhtunkhwa, 23640 Pakistan (Pakistan); Hussain, Ghulam [Faculty of Engineering Sciences, GIK Institute of Engineering Sciences and Technology, Topi, Khyber Pakhtunkhwa, 23640 Pakistan (Pakistan); Siddique, Salma [Department of Bioscience & Biotechnology, Sejong University, Seoul, 143-747 (Korea, Republic of); Iqbal, Muhammad Waqas [Department of Physics, Riphah Institute of Computing and Applied Sciences (RICAS), Riphah International University, Lahore (Pakistan); Murtaza, Ghulam [Centre for Advanced Studies in Physics, Government College University, Lahore 54000 (Pakistan); Ramay, Shahid Mahmood [Physics & Astronomy Department, College of Science, King Saud University, Riyadh 11451 (Saudi Arabia)

    2017-01-15

    It is possible to utilize the new class of materials for emerging two-dimensional (2D) spintronic applications. Here, the role of defects in the graphene interlayer and its influence on the spin valve signal is reported. The emergence of D peak in Raman spectrum reveals defects in the graphene layer. The linear I-V curve for defective and non-defective graphene samples indicate the ohmic nature of NiFe and graphene contact. A non-uniform magnetoresistive effect with a bump is persistently observed for defective graphene device at various temperatures, while a smooth and symmetric signal is detected for non-defective graphene spin valve. Parallel and antiparallel alignments of magnetization of magnetic materials shows low and high resistance states, respectively. The magnetoresistance (MR) ratio for defective graphene NiFe/graphene/NiFe spin valve is measured to be ~0.16% at 300 K which progresses to ~0.39% for non-defective graphene device at the same temperature. Similarly at 4.2 K the MR ratios are reported to be ~0.41% and ~0.78% for defective and non-defective graphene devices, respectively. Our investigation provides an evidence for relatively better response of the spin valve signal with high quality graphene interlayer.

  9. MnNi-based spin valve sensors combining high thermal stability, small footprint and pTesla detectivities

    Science.gov (United States)

    Silva, Marília; Leitao, Diana C.; Cardoso, Susana; Freitas, Paulo

    2018-05-01

    Magnetoresistive sensors with high thermal robustness, low noise and high spatial resolution are the answer to a number of challenging applications. Spin valve sensors including MnNi as antiferromagnet layer provide higher exchange bias field and improved thermal stability. In this work, the influence of the buffer layer type (Ta, NiFeCr) and thickness on key sensor parameters (e.g. offset field, Hf) is investigated. A Ta buffer layer promotes a strong (111) texture which leads to a higher value of MR. In contrast, Hf is lower for NiFeCr buffer. Micrometric sensors display thermal noise levels of 1 nT/Hz1/2 and 571 pT/Hz1/2 for a sensor height (h) of 2 and 4 μm, respectively. The temperature dependence of MR and sensitivity is also addressed and compared with MnIr based spin valves. In this case, MR abruptly decreases after heating at 160°C (without magnetic field), contrary to MnNi-based spin valves, where only a 10% MR decrease (relative to the initial value) is seen at 275°C. Finally, to further decrease the noise levels and improve detectivity, MnNi spin-valves are deposited vertically, and connected in parallel and series (in-plane) to create a device with low resistance and high sensitivity. A field detection at thermal level of 346 pT/Hz1/2 is achieved for a device with a total of 300 SVs (4 vertical, 15 in series, 5 in parallel).

  10. Large spin current injection in nano-pillar-based lateral spin valve

    Energy Technology Data Exchange (ETDEWEB)

    Nomura, Tatsuya [Department of Physics, Kyushu University, 744 Motooka, Fukuoka, 819-0395 (Japan); Ohnishi, Kohei; Kimura, Takashi, E-mail: t-kimu@phys.kyushu-u.ac.jp [Department of Physics, Kyushu University, 744 Motooka, Fukuoka, 819-0395 (Japan); Research Center for Quantum Nano-Spin Sciences, Kyushu University, 744 Motooka, Fukuoka, 819-0395 (Japan)

    2016-08-26

    We have investigated the influence of the injection of a large pure spin current on a magnetization process of a non-locally located ferromagnetic dot in nano-pillar-based lateral spin valves. Here, we prepared two kinds of the nano-pillar-type lateral spin valve based on Py nanodots and CoFeAl nanodots fabricated on a Cu film. In the Py/Cu lateral spin valve, although any significant change of the magnetization process of the Py nanodot has not been observed at room temperature. The magnetization reversal process is found to be modified by injecting a large pure spin current at 77 K. Switching the magnetization by the nonlocal spin injection has also been demonstrated at 77 K. In the CoFeAl/Cu lateral spin valve, a room temperature spin valve signal was strongly enhanced from the Py/Cu lateral spin valve because of the highly spin-polarized CoFeAl electrodes. The room temperature nonlocal switching has been demonstrated in the CoFeAl/Cu lateral spin valve.

  11. Spin motive forces, 'measurements', and spin-valves

    International Nuclear Information System (INIS)

    Barnes, S.E.

    2007-01-01

    Discussed is the spin motive force (smf) produced by a spin valve, this reflecting its dynamics. Relaxation implies an implicit measurement of the magnetization of the free layer of a valve. It is shown this has implications for the angular dependence of the torque transfer. Some discussion of recent experiments is included

  12. Inverse spin-valve effect in nanoscale Si-based spin-valve devices

    Science.gov (United States)

    Hiep, Duong Dinh; Tanaka, Masaaki; Hai, Pham Nam

    2017-12-01

    We investigated the spin-valve effect in nano-scale silicon (Si)-based spin-valve devices using a Fe/MgO/Ge spin injector/detector deposited on Si by molecular beam epitaxy. For a device with a 20 nm Si channel, we observed clear magnetoresistance up to 3% at low temperature when a magnetic field was applied in the film plane along the Si channel transport direction. A large spin-dependent output voltage of 20 mV was observed at a bias voltage of 0.9 V at 15 K, which is among the highest values in lateral spin-valve devices reported so far. Furthermore, we observed that the sign of the spin-valve effect is reversed at low temperatures, suggesting the possibility of a spin-blockade effect of defect states in the MgO/Ge tunneling barrier.

  13. Enhanced magnetoresistance in graphene spin valve

    Energy Technology Data Exchange (ETDEWEB)

    Iqbal, Muhammad Zahir, E-mail: zahir.upc@gmail.com [Faculty of Engineering Sciences, GIK Institute of Engineering Sciences and Technology, Topi 23640, Khyber Pakhtunkhwa (Pakistan); Hussain, Ghulam [Faculty of Engineering Sciences, GIK Institute of Engineering Sciences and Technology, Topi 23640, Khyber Pakhtunkhwa (Pakistan); Siddique, Salma [Department of Bioscience & Biotechnology, Sejong University, Seoul 143-747 (Korea, Republic of); Iqbal, Muhammad Waqas [Department of Physics, Riphah Institute of Computing and Applied Sciences (RICAS), Riphah International University, Lahore (Pakistan)

    2017-05-01

    Graphene has been explored as a promising candidate for spintronics due to its atomically flat structure and novel properties. Here we fabricate two spin valve junctions, one from directly grown graphene on Ni electrode (DG) and other from transferred graphene (TG). The magnetoresistance (MR) ratio for DG device is found to be higher than TG device i.e. ~0.73% and 0.14%, respectively. Also the spin polarization of Ni electrode is determined to be 6.03% at room temperature in case of DG device, however it reduces to 2.1% for TG device. From this analysis, we infer how environmental exposure of the sample degrades the spin properties of the magnetic junctions. Moreover, the transport measurements reveal linear behavior for current-voltage (I-V) characteristics, indicating ohmic behavior of the junctions. Our findings unveil the efficiency of direct growth of graphene for spin filtering mechanism in spin valve devices.

  14. Nanosized perpendicular organic spin-valves

    Energy Technology Data Exchange (ETDEWEB)

    Göckeritz, Robert; Homonnay, Nico; Müller, Alexander; Richter, Tim [Institut für Physik, Martin Luther University Halle-Wittenberg, 06099 Halle (Saale) (Germany); Fuhrmann, Bodo [Interdisziplinäres Zentrum für Materialwissenschaften, Martin Luther University Halle-Wittenberg, 06099 Halle (Saale) (Germany); Schmidt, Georg, E-mail: georg.schmidt@physik.uni-halle.de [Institut für Physik, Martin Luther University Halle-Wittenberg, 06099 Halle (Saale) (Germany); Interdisziplinäres Zentrum für Materialwissenschaften, Martin Luther University Halle-Wittenberg, 06099 Halle (Saale) (Germany)

    2015-03-09

    A fabrication process for perpendicular organic spin-valve devices based on the organic semiconductor Alq3 has been developed which offers the possibility to achieve active device areas of less than 500 × 500 nm{sup 2} and is flexible in terms of material choice for the active layers. Characterization of the resulting devices shows a large magnetoresistance of sometimes more than 100%, however with equally large variation from device to device. Comparison with large area spin-valves indicates that the magnetoresistance of both large and small devices most likely originates from tunneling through pinholes and tunneling magnetoresistance.

  15. Spin Valve Systems for Angle Sensor Applications

    OpenAIRE

    Johnson, Andrew

    2004-01-01

    A contact-less sensor with the ability to measure over a 360° range has been long sought after in the automotive industry. Such a sensor could be realized by utilizing the angle dependence of the Giant Magneto Resistance (GMR) Effect in a special type of magnetic multilayer called a spin valve arranged in a wheatstone bridge circuit [Spo96]. A spin valve consists of two ferromagnetic layers separated by nonmagnetic spacer layer where the magnetization of one of the ferromagnetic layers is pin...

  16. Graphene spin valve: An angle sensor

    Energy Technology Data Exchange (ETDEWEB)

    Iqbal, Muhammad Zahir, E-mail: zahir.upc@gmail.com [Faculty of Engineering Sciences, GIK Institute of Engineering Sciences and Technology, Topi 23640, Khyber Pakhtunkhwa (Pakistan); Hussain, Ghulam [Faculty of Engineering Sciences, GIK Institute of Engineering Sciences and Technology, Topi 23640, Khyber Pakhtunkhwa (Pakistan); Siddique, Salma [Department of Bioscience & Biotechnology, Sejong University, Seoul 143-747 (Korea, Republic of); Iqbal, Muhammad Waqas [Department of Physics, Riphah Institute of Computing and Applied Sciences (RICAS), Riphah International University, Lahore (Pakistan)

    2017-06-15

    Graphene spin valves can be optimized for various spintronic applications by tuning the associated experimental parameters. In this work, we report the angle dependent magnetoresistance (MR) in graphene spin valve for different orientations of applied magnetic field (B). The switching points of spin valve signals show a clear shift towards higher B for each increasing angle of the applied field, thus sensing the response for respective orientation of the magnetic field. The angular variation of B shifts the switching points from ±95 G to ±925 G as the angle is varied from 0° to 90° at 300 K. The observed shifts in switching points become more pronounced (±165 G to ±1450 G) at 4.2 K for similar orientation. A monotonic increase in MR ratio is observed as the angle of magnetic field is varied in the vertical direction at 300 K and 4.2 K temperatures. This variation of B (from 0° to 90°) increases the magnitude of MR ratio from ∼0.08% to ∼0.14% at 300 K, while at 4.2 K it progresses to ∼0.39% from ∼0.14%. The sensitivity related to angular variation of such spin valve structure can be employed for angle sensing applications.

  17. Spin current through quantum-dot spin valves

    International Nuclear Information System (INIS)

    Wang, J; Xing, D Y

    2006-01-01

    We report a theoretical study of the influence of the Coulomb interaction on the equilibrium spin current in a quantum-dot spin valve, in which the quantum dot described by the Anderson impurity model is coupled to two ferromagnetic leads with noncollinear magnetizations. In the Kondo regime, electrons transmit through the quantum dot via higher-order virtual processes, in which the spin of either lead electrons or a localized electron on the quantum dot may reverse. It is found that the magnitude of the spin current decreases with increasing Coulomb interactions due to spin flip effects on the dot. However, the spatial direction of the spin current remains unchanged; it is determined only by the exchange coupling between two noncollinear magnetizations

  18. Improved corrosion resistance of spin-valve film

    International Nuclear Information System (INIS)

    Tetsukawa, H.; Hommura, H.; Okabe, A.; Soda, Y.

    2007-01-01

    We investigated the corrosion behavior and magnetoresistance of spin-valve film in order to improve the corrosion resistance of the spin-valve head for a tape recording system. The conventional spin-valve head (sub./Ta/NiFe/CoFe/Cu/CoFe/PtMn/Ta) with no diamond-like carbon (DLC) protective layer showed poor corrosion resistance. This is because the CoFe for ferromagnetic layer and Cu for spacer in the spin-valve film exhibited poor corrosion resistance. The corrosion resistance of the CoFe film and Cu film improved with the addition of Ni and Au, respectively. The spin-valve film (sub./Ta/NiFe/CoNiFe/CuAu/CoNiFe/PtMn/Ta) showed higher pitting potential than the conventional spin-valve film by +0.45 V. This presents a significant improvement over the conventional spin-valve film. We also investigated the effect of the composition of ferromagnetic layer and spacer on the magnetoresistance of the spin-valve film. The magnetoresistance of the spin-valve film by substitution of CoNiFe for CoFe in ferromagnetic layer decreased slightly. The magnetoresistance of the spin-valve film decreased as the addition of Au of the spacer increased. The diffusion at CoNiFe/CuAu interface has not been observed in annealing process. The quantitative relation between corrosion resistance and magnetoresistance of spin-valve film, and its ferromagnetic layer and spacer's compositions have been clarified. The output voltage at 50 Oe of the corrosion-resistant spin-valve head with CoNiFe ferromagnetic layer and CuAu spacer was about 50% of that of the conventional spin-valve head

  19. Improved corrosion resistance of spin-valve film

    Energy Technology Data Exchange (ETDEWEB)

    Tetsukawa, H. [Sony Corporation, 6-7-35 Kitashinagawa, Shinagawa-ku, Tokyo 141-0001 (Japan)]. E-mail: tetsukaw@arc.sony.co.jp; Hommura, H. [Sony Corporation, 6-7-35 Kitashinagawa, Shinagawa-ku, Tokyo 141-0001 (Japan); Okabe, A. [Sony Corporation, 6-7-35 Kitashinagawa, Shinagawa-ku, Tokyo 141-0001 (Japan); Soda, Y. [Sony Corporation, 6-7-35 Kitashinagawa, Shinagawa-ku, Tokyo 141-0001 (Japan)

    2007-06-15

    We investigated the corrosion behavior and magnetoresistance of spin-valve film in order to improve the corrosion resistance of the spin-valve head for a tape recording system. The conventional spin-valve head (sub./Ta/NiFe/CoFe/Cu/CoFe/PtMn/Ta) with no diamond-like carbon (DLC) protective layer showed poor corrosion resistance. This is because the CoFe for ferromagnetic layer and Cu for spacer in the spin-valve film exhibited poor corrosion resistance. The corrosion resistance of the CoFe film and Cu film improved with the addition of Ni and Au, respectively. The spin-valve film (sub./Ta/NiFe/CoNiFe/CuAu/CoNiFe/PtMn/Ta) showed higher pitting potential than the conventional spin-valve film by +0.45 V. This presents a significant improvement over the conventional spin-valve film. We also investigated the effect of the composition of ferromagnetic layer and spacer on the magnetoresistance of the spin-valve film. The magnetoresistance of the spin-valve film by substitution of CoNiFe for CoFe in ferromagnetic layer decreased slightly. The magnetoresistance of the spin-valve film decreased as the addition of Au of the spacer increased. The diffusion at CoNiFe/CuAu interface has not been observed in annealing process. The quantitative relation between corrosion resistance and magnetoresistance of spin-valve film, and its ferromagnetic layer and spacer's compositions have been clarified. The output voltage at 50 Oe of the corrosion-resistant spin-valve head with CoNiFe ferromagnetic layer and CuAu spacer was about 50% of that of the conventional spin-valve head.

  20. Spin injection and spin accumulation in all-metal mesoscopic spin valves

    NARCIS (Netherlands)

    Jedema, FJ; Nijboer, MS; Filip, AT; van Wees, BJ

    2003-01-01

    We study the electrical injection and detection of spin accumulation in lateral ferromagnetic-metal-nonmagnetic-metal-ferromagnetic-metal (F/N/F) spin valve devices with transparent interfaces. Different ferromagnetic metals, Permalloy (Py), cobalt (Co), and nickel (Ni), are used as electrical spin

  1. Magnetic structure of the spin valve interface

    International Nuclear Information System (INIS)

    Nicholson, D.M.C.; Butler, W.H.; Zhang, X.; MacLaren, J.M.; Gurney, B.A.; Speriosu, V.S.

    1994-01-01

    Nonferromagnetic atoms present at Ni/Cu and Permalloy/Cu interfaces in sputtered spin valve magnetoresistive layered structures have been shown to cause reduced magnetoresistance. Here we show that a model in which the moments on the Ni atoms in the interfacial region of Ni/Cu are reduced substantially by interdiffusion with Cu is consistent with the experimental results. In contrast, we believe that moments persist at the permalloy/Cu interface, which first principle total energy calculations suggest will be disordered at finite temperatures. These reduced or disordered moments are expected to significantly reduce the GMR

  2. Spin current and spin transfer torque in ferromagnet/superconductor spin valves

    Science.gov (United States)

    Moen, Evan; Valls, Oriol T.

    2018-05-01

    Using fully self-consistent methods, we study spin transport in fabricable spin valve systems consisting of two magnetic layers, a superconducting layer, and a spacer normal layer between the ferromagnets. Our methods ensure that the proper relations between spin current gradients and spin transfer torques are satisfied. We present results as a function of geometrical parameters, interfacial barrier values, misalignment angle between the ferromagnets, and bias voltage. Our main results are for the spin current and spin accumulation as functions of position within the spin valve structure. We see precession of the spin current about the exchange fields within the ferromagnets, and penetration of the spin current into the superconductor for biases greater than the critical bias, defined in the text. The spin accumulation exhibits oscillating behavior in the normal metal, with a strong dependence on the physical parameters both as to the structure and formation of the peaks. We also study the bias dependence of the spatially averaged spin transfer torque and spin accumulation. We examine the critical-bias effect of these quantities, and their dependence on the physical parameters. Our results are predictive of the outcome of future experiments, as they take into account imperfect interfaces and a realistic geometry.

  3. Inverse Magnetoresistance in Polymer Spin Valves.

    Science.gov (United States)

    Ding, Shuaishuai; Tian, Yuan; Li, Yang; Mi, Wenbo; Dong, Huanli; Zhang, Xiaotao; Hu, Wenping; Zhu, Daoben

    2017-05-10

    In this work, both negative and positive magnetoresistance (MR) in solution-processed regioregular poly(3-hexylthiophene) (RR-P3HT) is observed in organic spin valves (OSVs) with vertical La 2/3 Sr 1/3 MnO 3 (LSMO)/P3HT/AlO x /Co configuration. The ferromagnetic (FM) LSMO electrode with near-atomic flatness is fabricated by a DC facing-target magnetron sputtering method. This research is focused on the origin of the MR inversion. Two types of devices are investigated in details: One with Co penetration shows a negative MR of 0.2%, while the other well-defined device with a nonlinear behavior has a positive MR of 15.6%. The MR measurements in LSMO/AlO x /Co and LSMO/Co junctions are carried to exclude the interference of insulating layer and two FM electrodes themselves. By examining the Co thicknesses and their corresponding magnetic hysteresis loops, a spin-dependent hybrid-interface-state model by Co penetration is induced to explain the MR sign inversion. These results proven by density functional theory (DFT) calculations may shed light on the controllable interfacial properties in designing novel OSV devices.

  4. Spin-polarized light-emitting diodes based on organic bipolar spin valves

    Science.gov (United States)

    Vardeny, Zeev Valentine; Nguyen, Tho Duc; Ehrenfreund, Eitan Avraham

    2017-10-25

    Spin-polarized organic light-emitting diodes are provided. Such spin-polarized organic light-emitting diodes incorporate ferromagnetic electrodes and show considerable spin-valve magneto-electroluminescence and magneto-conductivity responses, with voltage and temperature dependencies that originate from the bipolar spin-polarized space charge limited current.

  5. Spin valve sensor for biomolecular identification: Design, fabrication, and characterization

    Science.gov (United States)

    Li, Guanxiong

    Biomolecular identification, e.g., DNA recognition, has broad applications in biology and medicine such as gene expression analysis, disease diagnosis, and DNA fingerprinting. Therefore, we have been developing a magnetic biodetection technology based on giant magnetoresistive spin valve sensors and magnetic nanoparticle (developed for the magnetic nanoparticle detection, assuming the equivalent average field of magnetic nanoparticles and the coherent rotation of spin valve free layer magnetization. Micromagnetic simulations have also been performed for the spin valve sensors. The analytical model and micromagnetic simulations are found consistent with each other and are in good agreement with experiments. The prototype spin valve sensors have been fabricated at both micron and submicron scales. We demonstrated the detection of a single 2.8-mum magnetic microbead by micron-sized spin valve sensors. Based on polymer-mediated self-assembly and fine lithography, a bilayer lift-off process was developed to deposit magnetic nanoparticles onto the sensor surface in a controlled manner. With the lift-off deposition method, we have successfully demonstrated the room temperature detection of monodisperse 16-nm Fe3O 4 nanoparticles in a quantity from a few tens to several hundreds by submicron spin valve sensors, proving the feasibility of the nanoparticle detection. As desired for quantitative biodetection, a fairly linear dependence of sensor signal on the number of nanoparticles has been confirmed. The initial detection of DNA hybridization events labeled by magnetic nanoparticles further proved the magnetic biodetection concept.

  6. Local spin valve effect in lateral (Ga,MnAs/GaAs spin Esaki diode devices

    Directory of Open Access Journals (Sweden)

    M. Ciorga

    2011-06-01

    Full Text Available We report here on a local spin valve effect observed unambiguously in lateral all-semiconductor all-electrical spin injection devices, employing p+ −(Ga,MnAs/n+ −GaAs Esaki diode structures as spin aligning contacts. We discuss the observed local spin-valve signal as a result of the interplay between spin-transport-related contribution and the tunneling anisotropic magnetoresistance of the magnetic contacts. The magnitude of the spin-related magnetoresistance change is equal to 30 Ω which is twice the magnitude of the measured non-local signal.

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

    KAUST Repository

    Saidaoui, Hamed Ben Mohamed

    2014-05-28

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

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

    KAUST Repository

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

    2014-01-01

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

  9. Spin valve effect in single-atom contacts

    International Nuclear Information System (INIS)

    Ziegler, M; Neel, N; Berndt, R; Lazo, C; Ferriani, P; Heinze, S; Kroeger, J

    2011-01-01

    Magnetic single-atom contacts have been controllably fabricated with a scanning tunnelling microscope. A voltage-dependent spin valve effect with conductance variations of ∼40% is reproducibly observed from contacts comprising a Cr-covered tip and Co and Cr atoms on ferromagnetic nanoscale islands on W(110) with opposite magnetization. The spin-dependent conductances are interpreted from first-principles calculations in terms of the orbital character of the relevant electronic states of the junction.

  10. Magnon detection using a ferroic collinear multilayer spin valve.

    Science.gov (United States)

    Cramer, Joel; Fuhrmann, Felix; Ritzmann, Ulrike; Gall, Vanessa; Niizeki, Tomohiko; Ramos, Rafael; Qiu, Zhiyong; Hou, Dazhi; Kikkawa, Takashi; Sinova, Jairo; Nowak, Ulrich; Saitoh, Eiji; Kläui, Mathias

    2018-03-14

    Information transport and processing by pure magnonic spin currents in insulators is a promising alternative to conventional charge-current-driven spintronic devices. The absence of Joule heating and reduced spin wave damping in insulating ferromagnets have been suggested for implementing efficient logic devices. After the successful demonstration of a majority gate based on the superposition of spin waves, further components are required to perform complex logic operations. Here, we report on magnetization orientation-dependent spin current detection signals in collinear magnetic multilayers inspired by the functionality of a conventional spin valve. In Y 3 Fe 5 O 12 |CoO|Co, we find that the detection amplitude of spin currents emitted by ferromagnetic resonance spin pumping depends on the relative alignment of the Y 3 Fe 5 O 12 and Co magnetization. This yields a spin valve-like behavior with an amplitude change of 120% in our systems. We demonstrate the reliability of the effect and identify its origin by both temperature-dependent and power-dependent measurements.

  11. Large spin-valve effect in a lateral spin-valve device based on ferromagnetic semiconductor GaMnAs

    Science.gov (United States)

    Asahara, Hirokatsu; Kanaki, Toshiki; Ohya, Shinobu; Tanaka, Masaaki

    2018-03-01

    We investigate the spin-dependent transport properties of a lateral spin-valve device based on the ferromagnetic semiconductor GaMnAs. This device is composed of a GaMnAs channel layer grown on GaAs with a narrow trench across the channel. Its current-voltage characteristics show tunneling behavior. Large magnetoresistance (MR) ratios of more than ˜10% are obtained. These values are much larger than those (˜0.1%) reported for lateral-type spin metal-oxide-semiconductor field-effect transistors. The magnetic field direction dependence of the MR curve differs from that of the anisotropic magnetoresistance of GaMnAs, which confirms that the MR signal originates from the spin-valve effect between the GaMnAs electrodes.

  12. Thermal stability of low dose Ga+ ion irradiated spin valves

    International Nuclear Information System (INIS)

    Qi Xianjin; Wang Yingang; Zhou Guanghong; Li Ziquan

    2009-01-01

    The thermal stability of low dose Ga + ion irradiated spin valves has been investigated and compared with that of the as-prepared ones. The dependences of exchange field, measured using vibrating sample magnetometer at room temperature, on magnetic field sweep rate and time spent at negative saturation of the pinned ferromagnetic layer, and training effect were explored. The training effect is observed on both the irradiated spin valves and the as-prepared ones. The magnetic field sweep rate dependence of the exchange bias field of the irradiated spin valves is nearly the same as that of the as-prepared ones. For the as-prepared structure thermal activation has been observed, which showed that holding the irradiated structure at negative saturation of the pinned ferromagnetic layer for up to 28 hours results in no change in the exchange field. The results indicate that the thermal stability of the ion irradiated spin valves is the same as or even better than the as-prepared ones.

  13. Reduction of shunt current in buffer-free IrMn based spin-valve structures

    Science.gov (United States)

    Kocaman, B.; Akdoğan, N.

    2018-06-01

    The presence of thick buffer layers in magnetic sensor devices decreases sensor sensitivity due to shunt currents. With this motivation, we produced IrMn-based spin-valve multilayers without using buffer layer. We also studied the effects of post-annealing and IrMn thickness on exchange bias field (HEB) and blocking temperature (TB) of the system. Magnetization measurements indicate that both HEB and TB values are significantly enhanced with post-annealing of IrMn layer. In addition, we report that IrMn thickness of the system strongly influences the magnetization and transport characteristics of the spin-valve structures. We found that the minimum thickness of IrMn layer is 6 nm in order to achieve the lowest shunt current and high blocking temperature (>300 K). We also investigated the training of exchange bias to check the long-term durability of IrMn-based spin-valve structures for device applications.

  14. Spin-dependent Seebeck coefficients of Ni80Fe20 and Co in nanopillar spin valves

    NARCIS (Netherlands)

    Dejene, F. K.; Flipse, J.; van Wees, B. J.

    2012-01-01

    We have experimentally determined the spin-dependent Seebeck coefficient of permalloy (Ni80Fe20) and cobalt (Co) using nanopillar spin valve devices, a stack of two ferromagnetic layers separated by a nonmagnetic layer. The devices were specifically designed to separate heat-related effects from

  15. Flexible semi-transparent organic spin valve based on bathocuproine

    International Nuclear Information System (INIS)

    Sun, Xiangnan; Bedoya-Pinto, Amilcar; Llopis, Roger; Casanova, Fèlix; Hueso, Luis E.

    2014-01-01

    Organic semiconductors are attractive materials for advanced spintronic applications due to their long spin lifetimes and, simultaneously, their mechanical flexibility. With the aim of combining these advantages in a single device, we report on the fabrication and properties of a mechanically flexible bathocuproine-based spin valve. This organic spin device shows great stability on both electrical and magneto-transport properties upon mechanical bending at different radius (up to r = 5 mm), while featuring long-lasting endurance (on bending over 50 times). The room-temperature magnetoresistance ratio reaches up to 3.5%, and is notably preserved under air atmosphere. The observation of spin transport at room-temperature, combined with the outstanding mechanical properties and air stability, highlights the potential of bathocuproine-based spin devices towards applications.

  16. Spin-resolved electron waiting times in a quantum-dot spin valve

    Science.gov (United States)

    Tang, Gaomin; Xu, Fuming; Mi, Shuo; Wang, Jian

    2018-04-01

    We study the electronic waiting-time distributions (WTDs) in a noninteracting quantum-dot spin valve by varying spin polarization and the noncollinear angle between the magnetizations of the leads using the scattering matrix approach. Since the quantum-dot spin valve involves two channels (spin up and down) in both the incoming and outgoing channels, we study three different kinds of WTDs, which are two-channel WTD, spin-resolved single-channel WTD, and cross-channel WTD. We analyze the behaviors of WTDs in short times, correlated with the current behaviors for different spin polarizations and noncollinear angles. Cross-channel WTD reflects the correlation between two spin channels and can be used to characterize the spin-transfer torque process. We study the influence of the earlier detection on the subsequent detection from the perspective of cross-channel WTD, and define the influence degree quantity as the cumulative absolute difference between cross-channel WTDs and first-passage time distributions to quantitatively characterize the spin-flip process. We observe that influence degree versus spin-transfer torque for different noncollinear angles as well as different polarizations collapse into a single curve showing universal behaviors. This demonstrates that cross-channel WTDs can be a pathway to characterize spin correlation in spintronics system.

  17. Giant magneto-spin-Seebeck effect and magnon transfer torques in insulating spin valves

    Science.gov (United States)

    Cheng, Yihong; Chen, Kai; Zhang, Shufeng

    2018-01-01

    We theoretically study magnon transport in an insulating spin valve (ISV) made of an antiferromagnetic insulator sandwiched between two ferromagnetic insulator (FI) layers. In the conventional metal-based spin valve, the electron spins propagate between two metallic ferromagnetic layers, giving rise to giant magnetoresistance and spin transfer torque. Here, the incoherent magnons in the ISV serve as angular momentum carriers and are responsible for the angular momentum transport between two FI layers across the antiferromagnetic spacer. We predict two transport phenomena in the presence of the temperature gradient: a giant magneto-spin-Seebeck effect in which the output voltage signal is controlled by the relative orientation of the two FI layers and magnon transfer torque that can be used for switching the magnetization of the FI layers with a temperature gradient of the order of 0.1 Kelvin per nanometer.

  18. Spin relaxation through Kondo scattering in Cu/Py lateral spin valves

    Science.gov (United States)

    Batley, J. T.; Rosaond, M. C.; Ali, M.; Linfield, E. H.; Burnell, G.; Hickey, B. J.

    Within non-magnetic metals it is reasonable to expect the Elliot-Yafet mechanism to govern spin-relaxation and thus the temperature dependence of the spin diffusion length might be inversely proportional to resistivity. However, in lateral spin valves, measurements have found that at low temperatures the spin diffusion length unexpectedly decreases. We have fabricated lateral spin valves from Cu with different concentrations of magnetic impurities. Through temperature dependent charge and spin transport measurements we present clear evidence linking the presence of the Kondo effect within Cu to the suppression of the spin diffusion length below 30 K. We have calculated the spin-relaxation rate and isolated the contribution from magnetic impurities. At very low temperatures electron-electron interactions play a more prominent role in the Kondo effect. Well below the Kondo temperature a strong-coupling regime exists, where the moments become screened and the magnetic dephasing rate is reduced. We also investigate the effect of this low temperature regime (>1 K) on a pure spin current. This work shows the dominant role of Kondo scattering, even in low concentrations of order 1 ppm, within pure spin transport.

  19. Magneto-resistive and spin valve heads fundamentals and applications

    CERN Document Server

    Mallinson, John C

    2002-01-01

    This book is aims to be a comprehensive source on the physics and engineering of magneto-resistive heads. Most of the material is presented in a nonmathematical manner to make it more digestible for researchers, students, developers, and engineers.In addition to revising and updating material available in the first edition, Mallinson has added nine new chapters dealing with various aspects concerning spin valves, the electron spin tunneling effect, the electrostatic discharge effects, read amplifiers, and signal-to-noise ratios, making this a completely up-to-date reference.Th

  20. Superconducting spin valve effect in Fe/In based heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Leksin, Pavel; Schumann, Joachim; Kataev, Vladislav; Schmidt, Oliver; Buechner, Bernd [Leibniz Institute for Solid State and Materials Research IFW Dresden (Germany); Garifyanov, Nadir; Garifullin, Ilgiz [Zavoisky Physical-Technical Institute, Kazan Scientific Center, Russian Academy of Sciences (Russian Federation)

    2015-07-01

    We report on magnetic and superconducting properties of the spin-valve multilayer system CoOx/Fe1/Cu/Fe2/In. The Superconducting Spin Valve Effect (SSVE) assumes the T{sub c} difference between parallel (P) and antiparallel (AP) orientations of the Fe1 and Fe2 layers' magnetizations. The SSVE value oscillates and changes its sign when the Fe2 layer thickness d{sub Fe2} is varied from 0 to 5 nm. The SSVE value is positive, as expected, in the range 0.4 nm ≤ d{sub Fe2} ≤ 0.8 nm. For a rather broad range of thicknesses 1 nm ≤ d{sub Fe2} ≤ 2.6 nm the SSVE has negative sign assuming the inverse SSVE. Moreover, the magnitude of the inverse effect is larger than that of the positive direct effect. We attribute these oscillations to a quantum interference of the cooper pair wave functions in the magnetic part of the system. For most of the spin-valve samples from this set we experimentally realized the full switching between normal and superconducting states due to direct and inverse SSVE. The analysis of the experimental data has enabled the determination of all microscopic parameters of the studied system.

  1. A review on organic spintronic materials and devices: II. Magnetoresistance in organic spin valves and spin organic light emitting diodes

    Directory of Open Access Journals (Sweden)

    Rugang Geng

    2016-09-01

    Full Text Available In the preceding review paper, Paper I [Journal of Science: Advanced Materials and Devices 1 (2016 128–140], we showed the major experimental and theoretical studies on the first organic spintronic subject, namely organic magnetoresistance (OMAR in organic light emitting diodes (OLEDs. The topic has recently been of renewed interest as a result of a demonstration of the magneto-conductance (MC that exceeds 1000% at room temperature using a certain type of organic compounds and device operating condition. In this report, we will review two additional organic spintronic devices, namely organic spin valves (OSVs where only spin polarized holes exist to cause magnetoresistance (MR, and spin organic light emitting diodes (spin-OLEDs where both spin polarized holes and electrons are injected into the organic emissive layer to form a magneto-electroluminescence (MEL hysteretic loop. First, we outline the major advances in OSV studies for understanding the underlying physics of the spin transport mechanism in organic semiconductors (OSCs and the spin injection/detection at the organic/ferromagnet interface (spinterface. We also highlight some of outstanding challenges in this promising research field. Second, the first successful demonstration of spin-OLEDs is reviewed. We also discuss challenges to achieve the high performance devices. Finally, we suggest an outlook on the future of organic spintronics by using organic single crystals and aligned polymers for the spin transport layer, and a self-assembled monolayer to achieve more controllability for the spinterface.

  2. Spin injection and detection in lateral spin valves with hybrid interfaces

    Science.gov (United States)

    Wang, Le; Liu, Wenyu; Ying, Hao; Chen, Luchen; Lu, Zhanjie; Han, Shuo; Chen, Shanshan; Zhao, Bing; Xu, Xiaoguang; Jiang, Yong

    2018-06-01

    Spin injection and detection in lateral spin valves with hybrid interfaces comprising a Co/Ag transparent contact and a Co/MgO/Ag junction (III) are investigated at room temperature in comparison with pure Co/Ag transparent contacts (I) and Co/MgO/Ag junctions (II). The measured spin-accumulation signals of a type III device are five times higher than those for type I. The extracted spin diffusion length in Ag is 180 nm for all three types of devices. The enhancement of the spin signal of the hybrid structure is mainly attributed to the increase of the interfacial spin polarization from the Co/MgO/Ag junction.

  3. Valley- and spin-switch effects in molybdenum disulfide superconducting spin valve

    Science.gov (United States)

    Majidi, Leyla; Asgari, Reza

    2014-10-01

    We propose a hole-doped molybdenum disulfide (MoS2) superconducting spin valve (F/S/F) hybrid structure in which the Andreev reflection process is suppressed for all incoming waves with a determined range of the chemical potential in ferromagnetic (F) region and the cross-conductance in the right F region depends crucially on the configuration of magnetizations in the two F regions. Using the scattering formalism, we find that the transport is mediated purely by elastic electron cotunneling (CT) process in a parallel configuration and changes to the pure crossed Andreev reflection (CAR) process in the low-energy regime, without fixing of a unique parameter, by reversing the direction of magnetization in the right F region. This suggests both valley- and spin-switch effects between the perfect elastic CT and perfect CAR processes and makes the nonlocal charge current to be fully valley- and spin-polarized inside the right F region where the type of the polarizations can be changed by reversing the magnetization direction in the right F region. We further demonstrate that the presence of the strong spin-orbit interaction λ and an additional topological term (β ) in the Hamiltonian of MoS2 result in an enhancement of the charge conductance of the CT and CAR processes and make them to be present for long lengths of the superconducting region. Besides, we find that the thermal conductance of the structure with a small length of the highly doped superconducting region exhibits linear dependence on the temperature at low temperatures, whereas it enhances exponentially at higher temperatures. In particular, we demonstrate that the thermal conductance versus the strength of the exchange field (h ) in F region displays a maximum value at h <λ , which moves towards larger exchange fields by increasing the temperature.

  4. Vortex Flipping in Superconductor-Ferromagnet Spin Valve Structures

    Science.gov (United States)

    Patino, Edgar J.; Aprili, Marco; Blamire, Mark; Maeno, Yoshiteru

    2014-03-01

    We report in plane magnetization measurements on Ni/Nb/Ni/CoO and Co/Nb/Co/CoO spin valve structures with one of the ferromagnetic layers pinned by an antiferromagnetic layer. In samples with Ni, below the superconducting transition Tc, our results show strong evidence of vortex flipping driven by the ferromagnets magnetization. This is a direct consequence of proximity effect that leads to vortex supercurrents leakage into the ferromagnets. Here the polarized electron spins are subject to vortices magnetic field occasioning vortex flipping. Such novel mechanism has been made possible for the first time by fabrication of the F/S/F/AF multilayered spin valves with a thin-enough S layer to barely confine vortices inside as well as thin-enough F layers to align and control the magnetization within the plane. When Co is used there is no observation of vortex flipping effect. This is attributed to Co shorter coherence length. Interestingly instead a reduction in pinning field of about 400 Oe is observed when the Nb layer is in superconducting state. This effect cannot be explained in terms of vortex fields. In view of these facts any explanation must be directly related to proximity effect and thus a remarkable phenomenon that deserves further investigation. Programa Nacional de Ciencias Basicas COLCIENCIAS (No. 120452128168).

  5. Strain effects on anisotropic magnetoresistance in a nanowire spin valve

    Science.gov (United States)

    Hossain, Md I.; Maksud, M.; Subramanian, A.; Atulasimha, J.; Bandyopadhyay, S.

    2016-11-01

    The longitudinal magnetoresistance of a copper nanowire contacted by two cobalt contacts shows broad spin-valve peaks at room temperature. However, when the contacts are slightly heated, the peaks change into troughs which are signature of anisotropic magnetoresistance (AMR). Under heating, the differential thermal expansion of the contacts and the substrate generates a small strain in the cobalt contacts which enhances the AMR effect sufficiently to change the peak into a trough. This shows the extreme sensitivity of AMR to strain. The change in the AMR resistivity coefficient due to strain is estimated to be a few m Ω -m/microstrain.

  6. Influence of mechanical strain on magnetic characteristics of spin valves

    International Nuclear Information System (INIS)

    Ac, V; Anwarzai, B; Luby, S; Majkova, E

    2008-01-01

    Giant magnetoresistance (GMR) of Co and Fe-Co based e-beam evaporated spin valves with Cu and Au spacers was studied. The effect of strain on samples, which is detrimental in standard GMR sensors, was measured in a bending configuration. The different dependences of coercivity H c and magnetic field H ip in the point of inflection of MR loops vs. strain were found. For sample with Co/Au/Co core, H c , H ip increase with increasing compressive stress, whereas for sample with FeCo/Cu/Co core they increase with tensile stress. The highest relative change of MR ratio vs. bending in the strain interval ± 300 x 10 -6 is 1-2 % of the basic magnetoresistance and, practically, it does not influence the SV output

  7. Effective suppression of thermoelectric voltage in nonlocal spin-valve measurement

    Science.gov (United States)

    Ariki, Taisei; Nomura, Tatsuya; Ohnishi, Kohei; Kimura, Takashi

    2017-06-01

    We demonstrate that the background signal in the nonlocal spin-valve measurement can be sufficiently suppressed by optimizing the electrode design of the lateral spin valve. A relatively long length scale of heat propagation produces spin-independent thermoelectric signals under the combination of the Peltier and Seebeck effects. These unfavorable signals can be reduced by mixing the Peltier effects in two transparent ferromagnetic/nonmagnetic junctions. Proper understanding of the contribution from the heat current in no spin-current area is a key for effective reduction of the spin-independent background signal.

  8. Superconducting spin valves controlled by spiral re-orientation in B20-family magnets

    Science.gov (United States)

    Pugach, N. G.; Safonchik, M.; Champel, T.; Zhitomirsky, M. E.; Lähderanta, E.; Eschrig, M.; Lacroix, C.

    2017-10-01

    We propose a superconducting spin-triplet valve, which consists of a superconductor and an itinerant magnetic material, with the magnet showing an intrinsic non-collinear order characterized by a wave vector that may be aligned in a few equivalent preferred directions under the control of a weak external magnetic field. Re-orienting the spiral direction allows one to controllably modify long-range spin-triplet superconducting correlations, leading to spin-valve switching behavior. Our results indicate that the spin-valve effect may be noticeable. This bilayer may be used as a magnetic memory element for cryogenic nanoelectronics. It has the following advantages in comparison to superconducting spin valves proposed previously: (i) it contains only one magnetic layer, which may be more easily fabricated and controlled; (ii) its ground states are separated by a potential barrier, which solves the "half-select" problem of the addressed switch of memory elements.

  9. Magnetoresistance effect of heat generation in a single-molecular spin-valve

    International Nuclear Information System (INIS)

    Jiang, Feng; Yan, Yonghong; Wang, Shikuan; Yan, Yijing

    2016-01-01

    Based on non-equilibrium Green's functions' theory and small polaron transformation's technology, we study the heat generation by current through a single-molecular spin-valve. Numerical results indicate that the variation of spin polarization degree can change heat generation effectively, the spin-valve effect happens not only in electrical current but also in heat generation when Coulomb repulsion in quantum dot is smaller than phonon frequency and interestingly, when Coulomb repulsion is larger than phonon frequency, the inverse spin-valve effect appears by sweeping gate voltage and is enlarged with bias increasing. The inverse spin-valve effect will induce the unique heat magnetoresistance effect, which can be modulated from heat-resistance to heat-gain by gate voltage easily. - Highlights: • Spin-valve effect of heat generation happens when Coulomb repulsion in quantum dot is less than phonon frequency. • When Coulomb repulsion is larger than phonon frequency, inverse spin-valve effect appears and is enlarged with bias increasing. • The variation of spin polarization degree can change heat generation effectively. • The heat magnetoresistance can be modulated from heat-resistance to heat-gain by gate voltage easily.

  10. Aging effect of spin accumulation in non-local spin valves

    International Nuclear Information System (INIS)

    Zhao, Bing; Zhang, Ziyu; Chen, Xiaobing; Zhang, Xiaohan; Pan, Jiahui; Ma, Jiajun; Li, Juan; Wang, Zhicheng; Wang, Le; Xu, Xiaoguang; Jiang, Yong

    2017-01-01

    Highlights: • First time to reveal the whole temporal evolution life of spintronics devices. • The gradual oxidation of the junctions’ areas and that of the channel are confirmed to be the predominant factors to determine the temporal evolution. • Physically, the temporal evolution can be evaluated by theories of S. Takahashi and A. Fert. • This study may offer some useful advice for the design and protection of future industrial spintronics devices. - Abstract: A temporal evolution of spin accumulation of Co/MgO/Ag spin valves have been studied by using the nonlocal spin detection technique over almost a 3-month period in the ambient environment after the fabrication of the devices. Three different stages of the spin accumulation are first observed due to aging effect. The aging effect comes from two contributions–the gradual oxidation of the Ag/MgO and MgO/Co interfaces at the junctions’ areas which arises from the annealing process and the oxidation of the side surfaces of the Ag channels. The theories of S. Takahashi and A. Fert are introduced to evaluate the different evolution stages of spin accumulation.

  11. Aging effect of spin accumulation in non-local spin valves

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Bing; Zhang, Ziyu; Chen, Xiaobing; Zhang, Xiaohan; Pan, Jiahui; Ma, Jiajun; Li, Juan; Wang, Zhicheng [State Key Laboratory for Advanced Metals and Materials, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Wang, Le, E-mail: wangle@ruc.edu.cn [Department of Physics, Renmin University of China, Beijing 100872 (China); Xu, Xiaoguang, E-mail: xgxu@ustb.edu.cn [State Key Laboratory for Advanced Metals and Materials, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China); Jiang, Yong [State Key Laboratory for Advanced Metals and Materials, School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083 (China)

    2017-06-15

    Highlights: • First time to reveal the whole temporal evolution life of spintronics devices. • The gradual oxidation of the junctions’ areas and that of the channel are confirmed to be the predominant factors to determine the temporal evolution. • Physically, the temporal evolution can be evaluated by theories of S. Takahashi and A. Fert. • This study may offer some useful advice for the design and protection of future industrial spintronics devices. - Abstract: A temporal evolution of spin accumulation of Co/MgO/Ag spin valves have been studied by using the nonlocal spin detection technique over almost a 3-month period in the ambient environment after the fabrication of the devices. Three different stages of the spin accumulation are first observed due to aging effect. The aging effect comes from two contributions–the gradual oxidation of the Ag/MgO and MgO/Co interfaces at the junctions’ areas which arises from the annealing process and the oxidation of the side surfaces of the Ag channels. The theories of S. Takahashi and A. Fert are introduced to evaluate the different evolution stages of spin accumulation.

  12. Contact induced spin relaxation in graphene spin valves with Al2O3 and MgO tunnel barriers

    Directory of Open Access Journals (Sweden)

    Walid Amamou

    2016-03-01

    Full Text Available We investigate spin relaxation in graphene by systematically comparing the roles of spin absorption, other contact-induced effects (e.g., fringe fields, and bulk spin relaxation for graphene spin valves with MgO barriers, Al2O3 barriers, and transparent contacts. We obtain effective spin lifetimes by fitting the Hanle spin precession data with two models that include or exclude the effect of spin absorption. Results indicate that additional contact-induced spin relaxation other than spin absorption dominates the contact effect. For tunneling contacts, we find reasonable agreement between the two models with median discrepancy of ∼20% for MgO and ∼10% for Al2O3.

  13. Role of the magnetic anisotropy in organic spin valves

    Directory of Open Access Journals (Sweden)

    V. Kalappattil

    2017-09-01

    Full Text Available Magnetic anisotropy plays an important role in determining the magnetic functionality of thin film based electronic devices. We present here, the first systematic study of the correlation between magnetoresistance (MR response in organic spin valves (OSVs and magnetic anisotropy of the bottom ferromagnetic electrode over a wide temperature range (10 K–350 K. The magnetic anisotropy of a La0.67Sr0.33MnO3 (LSMO film epitaxially grown on a SrTiO3 (STO substrate was manipulated by reducing film thickness from 200 nm to 20 nm. Substrate-induced compressive strain was shown to drastically increase the bulk in-plane magnetic anisotropy when the LSMO became thinner. In contrast, the MR response of LSMO/OSC/Co OSVs for many organic semiconductors (OSCs does not depend on either the in-plane magnetic anisotropy of the LSMO electrodes or their bulk magnetization. All the studied OSV devices show a similar temperature dependence of MR, indicating a similar temperature-dependent spinterface effect irrespective of LSMO thickness, resulting from the orbital hybridization of carriers at the OSC/LSMO interface.

  14. Current-induced magnetization changes in a spin valve due to incoherent emission of non-equilibrium magnons

    OpenAIRE

    Kozub, V. I.; Caro, J.

    2004-01-01

    We describe spin transfer in a ferromagnet/normal metal/ferromagnet spin-valve point contact. Spin is transferred from the spin-polarized device current to the magnetization of the free layer by the mechanism of incoherent magnon emission by electrons. Our approach is based on the rate equation for the magnon occupation, using Fermi's golden rule for magnon emission and absorption and the non-equilibrium electron distribution for a biased spin valve. The magnon emission reduces the magnetizat...

  15. Magnetoresistance in hybrid organic spin valves at the onset of multiple-step tunneling

    NARCIS (Netherlands)

    Schoonus, J.J.H.M.; Lumens, P.G.E.; Wagemans, W.; Kohlhepp, J.T.; Bobbert, P.A.; Swagten, H.J.M.; Koopmans, B.

    2009-01-01

    By combining experiments with simple model calculations, we obtain new insight in spin transport through hybrid, CoFeB/Al2O3(1.5nm)/tris(8- hydroxyquinoline)aluminium (Alq3)/Co spin valves. We have measured the characteristic changes in the I-V behavior as well as the intrinsic loss of

  16. The multi-step tunneling analogue of conductivity mismatch in organic spin valves

    NARCIS (Netherlands)

    Tran, T. Lan Ahn; Le, T.Q.; Sanderink, Johannes G.M.; van der Wiel, Wilfred Gerard; de Jong, Machiel Pieter

    Carbon-based, molecular semiconductors offer several attractive attributes for spintronics, such as exceptionally weak spin-orbit coupling and compatibility with bottom-up nanofabrication. In spite of the promising properties of organic spin valves, however, the physical mechanisms governing

  17. Transcatheter, valve-in-valve transapical aortic and mitral valve implantation, in a high risk patient with aortic and mitral prosthetic valve stenoses

    Directory of Open Access Journals (Sweden)

    Harish Ramakrishna

    2015-01-01

    Full Text Available Transcatheter valve implantation continues to grow worldwide and has been used principally for the nonsurgical management of native aortic valvular disease-as a potentially less invasive method of valve replacement in high-risk and inoperable patients with severe aortic valve stenosis. Given the burden of valvular heart disease in the general population and the increasing numbers of patients who have had previous valve operations, we are now seeing a growing number of high-risk patients presenting with prosthetic valve stenosis, who are not potential surgical candidates. For this high-risk subset transcatheter valve delivery may be the only option. Here, we present an inoperable patient with severe, prosthetic valve aortic and mitral stenosis who was successfully treated with a trans catheter based approach, with a valve-in-valve implantation procedure of both aortic and mitral valves.

  18. Spin filter effect of hBN/Co detector electrodes in a 3D topological insulator spin valve

    Science.gov (United States)

    Vaklinova, Kristina; Polyudov, Katharina; Burghard, Marko; Kern, Klaus

    2018-03-01

    Topological insulators emerge as promising components of spintronic devices, in particular for applications where all-electrical spin control is essential. While the capability of these materials to generate spin-polarized currents is well established, only very little is known about the spin injection/extraction into/out of them. Here, we explore the switching behavior of lateral spin valves comprising the 3D topological insulator Bi2Te2Se as channel, which is separated from ferromagnetic Cobalt detector contacts by an ultrathin hexagonal boron nitride (hBN) tunnel barrier. The corresponding contact resistance displays a notable variation, which is correlated with a change of the switching characteristics of the spin valve. For contact resistances below ~5 kΩ, the hysteresis in the switching curve reverses upon reversing the applied current, as expected for spin-polarized currents carried by the helical surface states. By contrast, for higher contact resistances an opposite polarity of the hysteresis loop is observed, which is independent of the current direction, a behavior signifying negative spin detection efficiency of the multilayer hBN/Co contacts combined with bias-induced spin signal inversion. Our findings suggest the possibility to tune the spin exchange across the interface between a ferromagnetic metal and a topological insulator through the number of intervening hBN layers.

  19. High Reliability Cryogenic Piezoelectric Valve Actuator, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Cryogenic fluid valves are subject to harsh exposure and actuators to drive these valves require robust performance and high reliability. DSM's piezoelectric...

  20. The effect of electrodes on 11 acene molecular spin valve: Semi-empirical study

    Science.gov (United States)

    Aadhityan, A.; Preferencial Kala, C.; John Thiruvadigal, D.

    2017-10-01

    A new revolution in electronics is molecular spintronics, with the contemporary evolution of the two novel disciplines of spintronics and molecular electronics. The key point is the creation of molecular spin valve which consists of a diamagnetic molecule in between two magnetic leads. In this paper, non-equilibrium Green's function (NEGF) combined with Extended Huckel Theory (EHT); a semi-empirical approach is used to analyse the electron transport characteristics of 11 acene molecular spin valve. We examine the spin-dependence transport on 11 acene molecular junction with various semi-infinite electrodes as Iron, Cobalt and Nickel. To analyse the spin-dependence transport properties the left and right electrodes are joined to the central region in parallel and anti-parallel configurations. We computed spin polarised device density of states, projected device density of states of carbon and the electrode element, and transmission of these devices. The results demonstrate that the effect of electrodes modifying the spin-dependence behaviours of these systems in a controlled way. In Parallel and anti-parallel configuration the separation of spin up and spin down is lager in the case of iron electrode than nickel and cobalt electrodes. It shows that iron is the best electrode for 11 acene spin valve device. Our theoretical results are reasonably impressive and trigger our motivation for comprehending the transport properties of these molecular-sized contacts.

  1. Magnetoresistance Effect in NiFe/BP/NiFe Vertical Spin Valve Devices

    Directory of Open Access Journals (Sweden)

    Leilei Xu

    2017-01-01

    Full Text Available Two-dimensional (2D layered materials such as graphene and transition metal dichalcogenides are emerging candidates for spintronic applications. Here, we report magnetoresistance (MR properties of a black phosphorus (BP spin valve devices consisting of thin BP flakes contacted by NiFe ferromagnetic (FM electrodes. The spin valve effect has been observed from room temperature to 4 K, with MR magnitudes of 0.57% at 4 K and 0.23% at 300 K. In addition, the spin valve resistance is found to decrease monotonically as temperature is decreased, indicating that the BP thin film works as a conductive interlayer between the NiFe electrodes.

  2. Organic Spin-Valves and Beyond: Spin Injection and Transport in Organic Semiconductors and the Effect of Interfacial Engineering.

    Science.gov (United States)

    Jang, Hyuk-Jae; Richter, Curt A

    2017-01-01

    Since the first observation of the spin-valve effect through organic semiconductors, efforts to realize novel spintronic technologies based on organic semiconductors have been rapidly growing. However, a complete understanding of spin-polarized carrier injection and transport in organic semiconductors is still lacking and under debate. For example, there is still no clear understanding of major spin-flip mechanisms in organic semiconductors and the role of hybrid metal-organic interfaces in spin injection. Recent findings suggest that organic single crystals can provide spin-transport media with much less structural disorder relative to organic thin films, thus reducing momentum scattering. Additionally, modification of the band energetics, morphology, and even spin magnetic moment at the metal-organic interface by interface engineering can greatly impact the efficiency of spin-polarized carrier injection. Here, progress on efficient spin-polarized carrier injection into organic semiconductors from ferromagnetic metals by using various interface engineering techniques is presented, such as inserting a metallic interlayer, a molecular self-assembled monolayer (SAM), and a ballistic carrier emitter. In addition, efforts to realize long spin transport in single-crystalline organic semiconductors are discussed. The focus here is on understanding and maximizing spin-polarized carrier injection and transport in organic semiconductors and insight is provided for the realization of emerging organic spintronics technologies. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Magnetostrictive GMR spin valves with composite FeGa/FeCo free layers

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Luping [Key Laboratory of Magnetic Materials and Devices & Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Institute of Materials Science, School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); Zhan, Qingfeng, E-mail: zhanqf@nimte.ac.cn, E-mail: runweili@nimte.ac.cn; Yang, Huali; Li, Huihui; Zhang, Shuanglan; Liu, Yiwei; Wang, Baomin; Li, Run-Wei, E-mail: zhanqf@nimte.ac.cn, E-mail: runweili@nimte.ac.cn [Key Laboratory of Magnetic Materials and Devices & Zhejiang Province Key Laboratory of Magnetic Materials and Application Technology, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Tan, Xiaohua [Institute of Materials Science, School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China)

    2016-03-15

    We have fabricated strain-sensitive spin valves on flexible substrates by utilizing the large magnetostrictive FeGa alloy to promote the strain sensitivity and the composite free layer of FeGa/FeCo to avoid the drastic reduction of giant magnetoresistance (GMR) ratio. This kind of spin valve (SV-FeGa/FeCo) displays a MR ratio about 5.9%, which is comparable to that of the conventional spin valve (SV-FeCo) with a single FeCo free layer. Different from the previously reported works on magnetostrictive spin valves, the SV-FeGa/FeCo displays an asymmetric strain dependent GMR behavior. Upon increasing the lateral strain, the MR ratio for the ascending branch decreases more quickly than that for the descending branch, which is ascribed to the formation of a spiraling spin structure around the FeGa/FeCo interface under the combined influences of both magnetic field and mechanical strain. A strain sensitivity of GF = 7.2 was achieved at a magnetic bias field of -30 Oe in flexible SV-FeGa/FeCo, which is significantly larger than that of SV-FeCo.

  4. Magnetostrictive GMR spin valves with composite FeGa/FeCo free layers

    International Nuclear Information System (INIS)

    Liu, Luping; Zhan, Qingfeng; Yang, Huali; Li, Huihui; Zhang, Shuanglan; Liu, Yiwei; Wang, Baomin; Li, Run-Wei; Tan, Xiaohua

    2016-01-01

    We have fabricated strain-sensitive spin valves on flexible substrates by utilizing the large magnetostrictive FeGa alloy to promote the strain sensitivity and the composite free layer of FeGa/FeCo to avoid the drastic reduction of giant magnetoresistance (GMR) ratio. This kind of spin valve (SV-FeGa/FeCo) displays a MR ratio about 5.9%, which is comparable to that of the conventional spin valve (SV-FeCo) with a single FeCo free layer. Different from the previously reported works on magnetostrictive spin valves, the SV-FeGa/FeCo displays an asymmetric strain dependent GMR behavior. Upon increasing the lateral strain, the MR ratio for the ascending branch decreases more quickly than that for the descending branch, which is ascribed to the formation of a spiraling spin structure around the FeGa/FeCo interface under the combined influences of both magnetic field and mechanical strain. A strain sensitivity of GF = 7.2 was achieved at a magnetic bias field of -30 Oe in flexible SV-FeGa/FeCo, which is significantly larger than that of SV-FeCo.

  5. Magnetostrictive GMR spin valves with composite FeGa/FeCo free layers

    Science.gov (United States)

    Liu, Luping; Zhan, Qingfeng; Yang, Huali; Li, Huihui; Zhang, Shuanglan; Liu, Yiwei; Wang, Baomin; Tan, Xiaohua; Li, Run-Wei

    2016-03-01

    We have fabricated strain-sensitive spin valves on flexible substrates by utilizing the large magnetostrictive FeGa alloy to promote the strain sensitivity and the composite free layer of FeGa/FeCo to avoid the drastic reduction of giant magnetoresistance (GMR) ratio. This kind of spin valve (SV-FeGa/FeCo) displays a MR ratio about 5.9%, which is comparable to that of the conventional spin valve (SV-FeCo) with a single FeCo free layer. Different from the previously reported works on magnetostrictive spin valves, the SV-FeGa/FeCo displays an asymmetric strain dependent GMR behavior. Upon increasing the lateral strain, the MR ratio for the ascending branch decreases more quickly than that for the descending branch, which is ascribed to the formation of a spiraling spin structure around the FeGa/FeCo interface under the combined influences of both magnetic field and mechanical strain. A strain sensitivity of GF = 7.2 was achieved at a magnetic bias field of -30 Oe in flexible SV-FeGa/FeCo, which is significantly larger than that of SV-FeCo.

  6. High spin structure functions

    International Nuclear Information System (INIS)

    Khan, H.

    1990-01-01

    This thesis explores deep inelastic scattering of a lepton beam from a polarized nuclear target with spin J=1. After reviewing the formation for spin-1/2, the structure functions for a spin-1 target are defined in terms of the helicity amplitudes for forward compton scattering. A version of the convolution model, which incorporates relativistic and binding energy corrections is used to calculate the structure functions of a neutron target. A simple parameterization of these structure functions is given in terms of a few neutron wave function parameters and the free nucleon structure functions. This allows for an easy comparison of structure functions calculated using different neutron models. (author)

  7. Phenomena at very high spins

    International Nuclear Information System (INIS)

    Stephens, F.S.

    1980-03-01

    The present talk has three parts: first, a discussion of current ideas about the physics of very high spin states; second, some comments about noncollective behavior up to the highest spins where it is known, approx. 40 h; and finally, a presentation of the newest method for studying collective behavior up to spins of 60 to 70 h. The intention is that the overview presented in the first part will be sufficiently broad to indicate the relationship of the noncollective and collective behavior discussed in the other parts, and to provide some understanding of the compromise in behavior that seems to occur at the very highest spins. 13 figures

  8. Resistive switching and voltage induced modulation of tunneling magnetoresistance in nanosized perpendicular organic spin valves

    Directory of Open Access Journals (Sweden)

    Robert Göckeritz

    2016-04-01

    Full Text Available Nanoscale multifunctional perpendicular organic spin valves have been fabricated. The devices based on an La0.7Sr0.3MnO3/Alq3/Co trilayer show resistive switching of up to 4-5 orders of magnitude and magnetoresistance as high as -70% the latter even changing sign when voltage pulses are applied. This combination of phenomena is typically observed in multiferroic tunnel junctions where it is attributed to magnetoelectric coupling between a ferromagnet and a ferroelectric material. Modeling indicates that here the switching originates from a modification of the La0.7Sr0.3MnO3 surface. This modification influences the tunneling of charge carriers and thus both the electrical resistance and the tunneling magnetoresistance which occurs at pinholes in the organic layer.

  9. Measurement of variable magnetic reversal paths in electrically contacted pseudo-spin-valve rings

    International Nuclear Information System (INIS)

    Hayward, T J; Llandro, J; Schackert, F D O; Morecroft, D; Balsod, R B; Bland, J A C; Castano, F J; Ross, C A

    2007-01-01

    In this work we show that the measurement of single magnetic reversal events is of critical importance in order to correctly characterize the switching of magnetic microstructures. Magnetoresistance measurements are performed on two pseudo-spin-valve ring structures with high enough signal to noise to allow the probing of single reversal events. Using this technique we acquire 'switching spectra' which demonstrate that the rings exhibit a range of variable reversal paths, including a bistable reversal mechanism of the hard layer, where the two switching routes have substantially different switching fields. The signature of the variable reversal paths would have been obscured in field cycle averaged data and in the bistable case would cause a fundamental misinterpretation of the reversal behaviour

  10. Electrical spin injection into high mobility 2D systems.

    Science.gov (United States)

    Oltscher, M; Ciorga, M; Utz, M; Schuh, D; Bougeard, D; Weiss, D

    2014-12-05

    We report on spin injection into a high mobility 2D electron system confined at an (Al,Ga)As/GaAs interface, using (Ga,Mn)As Esaki diode contacts as spin aligners. We measured a clear nonlocal spin valve signal, which varies nonmonotonically with the applied bias voltage. The magnitude of the signal cannot be described by the standard spin drift-diffusion model, because at maximum this would require the spin polarization of the injected current to be much larger than 100%, which is unphysical. A strong correlation of the spin signal with contact width and electron mean free path suggests that ballistic transport in the 2D region below ferromagnetic contacts should be taken into account to fully describe the results.

  11. Current-induced magnetic switching of a single molecule magnet on a spin valve

    International Nuclear Information System (INIS)

    Zhang, Xiao; Wang, Zheng-Chuan; Zheng, Qing-Rong; Zhu, Zheng-Gang; Su, Gang

    2015-01-01

    The current-induced magnetic switching of a single-molecule magnet (SMM) attached on the central region of a spin valve is explored, and the condition for the switching current is derived. Electrons flowing through the spin valve will interact with the SMM via the s–d exchange interaction, producing the spin accumulation that satisfies the spin diffusion equation. We further describe the spin motion of the SMM by a Heisenberg-like equation. Based on the linear stability analysis, we obtain the critical current from two coupled equations. The results of the critical current versus the external magnetic field indicate that one can manipulate the magnetic state of the SMM by an external magnetic field. - Highlights: • We theoretically study the current-induced magnetic switching of the SMM. • We describe the spin motion of the SMM by a Heisenberg-like equation. • We describe the spin accumulation by the spin diffusion equation. • We obtain the critical current by the linear stability analysis. • Our approach can be easily extended to other SMMs

  12. Current-induced magnetic switching of a single molecule magnet on a spin valve

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiao [Theoretical Condensed Matter Physics and Computational Materials Physics Laboratory, School of Physics, University of Chinese Academy of Sciences, Beijing 100049 (China); Wang, Zheng-Chuan, E-mail: wangzc@ucas.ac.cn [Theoretical Condensed Matter Physics and Computational Materials Physics Laboratory, School of Physics, University of Chinese Academy of Sciences, Beijing 100049 (China); Zheng, Qing-Rong [Theoretical Condensed Matter Physics and Computational Materials Physics Laboratory, School of Physics, University of Chinese Academy of Sciences, Beijing 100049 (China); Zhu, Zheng-Gang [Theoretical Condensed Matter Physics and Computational Materials Physics Laboratory, School of Physics, University of Chinese Academy of Sciences, Beijing 100049 (China); School of Electronics, Electric and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100049 (China); Su, Gang, E-mail: gsu@ucas.ac.cn [Theoretical Condensed Matter Physics and Computational Materials Physics Laboratory, School of Physics, University of Chinese Academy of Sciences, Beijing 100049 (China)

    2015-04-17

    The current-induced magnetic switching of a single-molecule magnet (SMM) attached on the central region of a spin valve is explored, and the condition for the switching current is derived. Electrons flowing through the spin valve will interact with the SMM via the s–d exchange interaction, producing the spin accumulation that satisfies the spin diffusion equation. We further describe the spin motion of the SMM by a Heisenberg-like equation. Based on the linear stability analysis, we obtain the critical current from two coupled equations. The results of the critical current versus the external magnetic field indicate that one can manipulate the magnetic state of the SMM by an external magnetic field. - Highlights: • We theoretically study the current-induced magnetic switching of the SMM. • We describe the spin motion of the SMM by a Heisenberg-like equation. • We describe the spin accumulation by the spin diffusion equation. • We obtain the critical current by the linear stability analysis. • Our approach can be easily extended to other SMMs.

  13. The magnetoresistive effect induced by stress in spin-valve structures

    International Nuclear Information System (INIS)

    Li-Jie, Qian; Xiao-Yong, Xu; Jing-Guo, Hu

    2009-01-01

    Using a method of free energy minimization, this paper investigates the magnetization properties of a ferromagnetic (FM) monolayer and an FM/antiferromagnetic (AFM) bilayer under a stress field, respectively. It then investigates the magnetoresistance (MR) of the spin-valve structure, which is built by an FM monolayer and an FM/AFM bilayer, and its dependence upon the applied stress field. The results show that under the stress field, the magnetization properties of the FM monolayer is obviously different from that of the FM/AFM bilayer, since the coupled AFM layer can obviously block the magnetization of the FM layer. This phenomenon makes the MR of the spin-valve structure become obvious. In detail, there are two behaviors for the MR of the spin-valve structure dependence upon the stress field distinguished by the coupling (FM coupling or AFM coupling) between the FM layer and the FM/AFM bilayer. Either behavior of the MR of the spin-valve structure depends on the stress field including its value and orientation. Based on these investigations, a perfect mechanical sensor at the nano-scale is suggested to be devised experimentally

  14. Interplay of Peltier and Seebeck Effects in Nanoscale Nonlocal Spin Valves

    NARCIS (Netherlands)

    Bakker, F. L.; Slachter, A.; Adam, J-P; van Wees, B. J.

    2010-01-01

    We have experimentally studied the role of thermoelectric effects in nanoscale nonlocal spin valve devices. A finite element thermoelectric model is developed to calculate the generated Seebeck voltages due to Peltier and Joule heating in the devices. By measuring the first, second, and third

  15. Analysis of high-pressure safety valves

    NARCIS (Netherlands)

    Beune, A.

    2009-01-01

    In presently used safety valve sizing standards the gas discharge capacity is based on a nozzle flow derived from ideal gas theory. At high pressures or low temperatures real gas effects can no longer be neglected, so the discharge coefficient corrected for flow losses cannot be assumed constant

  16. IV. Workshop on High Energy Spin Physics

    International Nuclear Information System (INIS)

    Nurushev, S.

    1992-01-01

    In this proceedings the results on high energy spin physics are summarized. The theory of spin phenomenon and the experimental results at intermediate energy and at high energy spin physics and new technical developments in polarization experiments are presented

  17. High Temperature, High Frequency Fuel Metering Valve, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Active Signal Technologies and its subcontractor Moog propose to develop a high-frequency actuator driven valve intended to achieve TRL 6 by the end of Phase II....

  18. On the temperature dependence of spin pumping in ferromagnet–topological insulator–ferromagnet spin valves

    Directory of Open Access Journals (Sweden)

    A.A. Baker

    Full Text Available Topological insulators (TIs have a large potential for spintronic devices owing to their spin-polarized, counter-propagating surface states. Recently, we have investigated spin pumping in a ferromagnet–TI–ferromagnet structure at room temperature. Here, we present the temperature-dependent measurement of spin pumping down to 10 K, which shows no variation with temperature. Keywords: Topological insulator, Spin pumping, Spintronics, Ferromagnetic resonance

  19. Magnetoresistance in hybrid organic spin valves at the onset of multiple-step tunneling.

    Science.gov (United States)

    Schoonus, J J H M; Lumens, P G E; Wagemans, W; Kohlhepp, J T; Bobbert, P A; Swagten, H J M; Koopmans, B

    2009-10-02

    By combining experiments with simple model calculations, we obtain new insight in spin transport through hybrid, CoFeB/Al2O3(1.5 nm)/tris(8-hydroxyquinoline)aluminium (Alq3)/Co spin valves. We have measured the characteristic changes in the I-V behavior as well as the intrinsic loss of magnetoresistance at the onset of multiple-step tunneling. In the regime of multiple-step tunneling, under the condition of low hopping rates, spin precession in the presence of hyperfine coupling is conjectured to be the relevant source of spin relaxation. A quantitative analysis leads to the prediction of a symmetric magnetoresistance around zero magnetic field in addition to the hysteretic magnetoresistance curves, which are indeed observed in our experiments.

  20. Gate-tunable large magnetoresistance in an all-semiconductor spin valve device.

    Science.gov (United States)

    Oltscher, M; Eberle, F; Kuczmik, T; Bayer, A; Schuh, D; Bougeard, D; Ciorga, M; Weiss, D

    2017-11-27

    A large spin-dependent and electric field-tunable magnetoresistance of a two-dimensional electron system is a key ingredient for the realization of many novel concepts for spin-based electronic devices. The low magnetoresistance observed during the last few decades in devices with lateral semiconducting transport channels between ferromagnetic source and drain contacts has been the main obstacle for realizing spin field effect transistor proposals. Here, we show both a large two-terminal magnetoresistance in a lateral spin valve device with a two-dimensional channel, with up to 80% resistance change, and tunability of the magnetoresistance by an electric gate. The enhanced magnetoresistance is due to finite electric field effects at the contact interface, which boost spin-to-charge conversion. The gating scheme that we use is based on switching between uni- and bidirectional spin diffusion, without resorting to spin-orbit coupling. Therefore, it can also be employed in materials with low spin-orbit coupling.

  1. Magnetotransport in spin-valve systems with amorphous magnetic and superconducting partial layers

    International Nuclear Information System (INIS)

    Steiner, Roland Johannes

    2006-01-01

    The first part of this work deals with the fabrication and characterisation of spin valves with an amorphous FeB layer acting as a weak ferromagnet embedded into the structure. In the second part of this work ferromagnet/superconductor hybrid structures are fabricated and the relevant magnetic field dependent transport phenomena are analyzed. The interlayer of a conventional spin valve was replaced by a superconducting niobium layer. Small applied fields close to the coercivity field of the involved ferromagnets - and thus far below the critical magnetic field of the superconductor - affected the critical temperature of the niobium layer. Measurements of the field dependent resistance and the critical temperature of a FM/SC/FMsystem showed a local maximum in the T c (H)- and the R(H)-curve. (orig.)

  2. Stretchable Spin Valve with Stable Magnetic Field Sensitivity by Ribbon-Patterned Periodic Wrinkles.

    Science.gov (United States)

    Li, Huihui; Zhan, Qingfeng; Liu, Yiwei; Liu, Luping; Yang, Huali; Zuo, Zhenghu; Shang, Tian; Wang, Baomin; Li, Run-Wei

    2016-04-26

    A strain-relief structure by combining the strain-engineered periodic wrinkles and the parallel ribbons was employed to fabricate flexible dual spin valves onto PDMS substrates in a direct sputtering method. The strain-relief structure can accommodate the biaxial strain accompanying with stretching operation (the uniaxial applied tensile strain and the induced transverse compressive strain due to the Poisson effect), thus significantly reducing the influence of the residual strain on the giant magnetoresistance (GMR) performance. The fabricated GMR dual spin-valve sensor exhibits the nearly unchanged MR ratio of 9.9%, magnetic field sensitivity up to 0.69%/Oe, and zero-field resistance in a wide range of stretching strain, making it promising for applications on a conformal shape or a movement part.

  3. Giant tunneling electroresistance effect driven by an electrically controlled spin valve at a complex oxide interface.

    Science.gov (United States)

    Burton, J D; Tsymbal, E Y

    2011-04-15

    A giant tunneling electroresistance effect may be achieved in a ferroelectric tunnel junction by exploiting the magnetoelectric effect at the interface between the ferroelectric barrier and a magnetic La(1-x)Sr(x)MnO3 electrode. Using first-principles density-functional theory we demonstrate that a few magnetic monolayers of La(1-x)Sr(x)MnO3 near the interface act, in response to ferroelectric polarization reversal, as an atomic-scale spin valve by filtering spin-dependent current. This produces more than an order of magnitude change in conductance, and thus constitutes a giant resistive switching effect.

  4. High-spin nuclear spectroscopy

    International Nuclear Information System (INIS)

    Diamond, R.M.

    1986-07-01

    High-spin spectroscopy is the study of the changes in nuclear structure, properties, and behavior with increasing angular momentum. It involves the complex interplay between collective and single-particle motion, between shape and deformation changes, particle alignments, and changes in the pairing correlations. A review of progress in theory, experimentation, and instrumentation in this field is given

  5. Photoemission microscopy study of picosecond magnetodynamics in spin-valve-type thin film elements

    International Nuclear Information System (INIS)

    Schneider, C.M.; Kaiser, A.; Wiemann, C.; Tieg, C.; Cramm, S.

    2010-01-01

    Exploring ultimate time scales of magnetic switching processes is an important issue in spin electronics. In spin valves or magnetic tunnelling junctions magnetic anisotropies and coupling phenomena alter the magnetodynamic response of the entire system. Understanding the role of these interactions is a key to the design of optimized devices. We have employed time-resolved X-ray photoemission microscopy to address the magnetodynamics in spin-valve-type model systems in the ns- and ps-regime. In Co/Cr/Fe(0 0 1) single crystal elements we find a strong influence of the magnetocrystalline anisotropy, which tends to suppress rotation processes. In addition, we observe a dynamic 'decoupling' of the layers. In low-anisotropy FeNi/Cr/FeCo trilayers, the interlayer coupling character determines the dynamic response. Particularly, rotational processes in the FeNi and FeCo layers are temporarily shifted to each other, which can be related to different coercivities of the individual layers. By contrast, the domain wall motion in both layers closely agrees, caused by an enhanced coupling due to the domain wall stray fields. Our examples demonstrate that the detailed magnetodynamics in coupled magnetic layers is quite complex and depends strongly on the timescale under consideration.

  6. Magnetic scanning gate microscopy of CoFeB lateral spin valve

    Directory of Open Access Journals (Sweden)

    Héctor Corte-León

    2017-05-01

    Full Text Available Devices comprised of CoFeB nanostructures with perpendicular magnetic anisotropy and non-magnetic Ta channel were operated in thermal lateral spin valve (LSV mode and studied by magnetotransport measurements and magnetic scanning gate microscopy (SGM. Due to the short spin diffusion length of Ta, the spin diffusion signal was suppressed, allowing the study of the contribution from the anomalous Nernst (ANE and anomalous Hall effects (AHE. The magnetotransport measurements identified the switching fields of the CoFeB nanostructures and demonstrated a combination of AHE and ANE when the devices were operated in thermally-driven spin-injection mode. Modified scanning probe microscopy probes were fabricated by placing a NdFeB magnetic bead (MB on the apex of a commercial Si probe. The dipole magnetic field distribution around the MB was characterized by using differential phase contrast technique and direct measurement of the switching field induced by the bead in the CoFeB nanodevices. Using SGM we demonstrate the influence of localized magnetic field on the CoFeB nanostructures near the non-magnetic channel. This approach provides a promising route towards the study of thermal and spin diffusion effects using local magnetic fields.

  7. Magnetic scanning gate microscopy of CoFeB lateral spin valve

    Science.gov (United States)

    Corte-León, Héctor; Scarioni, Alexander Fernandez; Mansell, Rhodri; Krzysteczko, Patryk; Cox, David; McGrouther, Damien; McVitie, Stephen; Cowburn, Russell; Schumacher, Hans W.; Antonov, Vladimir; Kazakova, Olga

    2017-05-01

    Devices comprised of CoFeB nanostructures with perpendicular magnetic anisotropy and non-magnetic Ta channel were operated in thermal lateral spin valve (LSV) mode and studied by magnetotransport measurements and magnetic scanning gate microscopy (SGM). Due to the short spin diffusion length of Ta, the spin diffusion signal was suppressed, allowing the study of the contribution from the anomalous Nernst (ANE) and anomalous Hall effects (AHE). The magnetotransport measurements identified the switching fields of the CoFeB nanostructures and demonstrated a combination of AHE and ANE when the devices were operated in thermally-driven spin-injection mode. Modified scanning probe microscopy probes were fabricated by placing a NdFeB magnetic bead (MB) on the apex of a commercial Si probe. The dipole magnetic field distribution around the MB was characterized by using differential phase contrast technique and direct measurement of the switching field induced by the bead in the CoFeB nanodevices. Using SGM we demonstrate the influence of localized magnetic field on the CoFeB nanostructures near the non-magnetic channel. This approach provides a promising route towards the study of thermal and spin diffusion effects using local magnetic fields.

  8. Microwave spectroscopy and electronic transport properties of ferromagnetic Josephson junctions and superconducting spin-valves

    Energy Technology Data Exchange (ETDEWEB)

    Thalmann, Marcel; Rudolf, Marcel; Pietsch, Torsten [Zukunftskolleg and Department of Physics, University of Konstanz, Universitaetsstrasse 10, 78464 Konstanz (Germany)

    2016-07-01

    Hybrid superconducting nanostructures recently attracted tremendous interest, due to their great potential in dissipation-less spin-electronics with unprecedented switching rates. The practical realisation of such devices, however, requires a complete understanding of the transfer and dynamics of spin- and charge currents between superconducting (S) and ferromagnetic (F) circuit elements, as well as the coupling between spin- and charge degrees of freedom in these systems. We investigate novel transport phenomena in superconductor-ferromagnet hybrid nanostructures under non-equilibrium conditions. Microwave spectroscopy is used to elucidate fundamental questions related to the complex interplay of competing order parameters and the question of relaxation mechanisms of non-equilibrium distributions with respect to spin, charge and energy. Recent experiments on two complimentary device structures are discussed: (I) in diffusive S/F/S Josephson junctions with non-sinusoidal current-phase relationship and (II) local and non-local transport measurements and microwave spectroscopy in F/S/F lateral spin-valves.

  9. Development of high-spin isomer beams

    International Nuclear Information System (INIS)

    Zhou Xiaohong

    2000-01-01

    The physical motivations with high-spin isomer beams were introduced. Taking HSIB of RIKEN as an example, the methods to produce, separate, transport and purity high-spin isomer beams were described briefly, and the detection of γ rays emitted from the reactions induced by the high-spin isomer beams was presented. Finally, the progress to develop the high-spin isomers in the N = 83 isotones as second beams was stressed

  10. Role of the antiferromagnetic pinning layer on spin wave properties in IrMn/NiFe based spin-valves

    Energy Technology Data Exchange (ETDEWEB)

    Gubbiotti, G., E-mail: gubbiotti@fisica.unipg.it; Tacchi, S. [Istituto Officina dei Materiali del CNR (IOM-CNR), Unità di Perugia, I-06123 Perugia (Italy); Del Bianco, L. [Department of Physics and Astronomy, University of Bologna, I-40127 Bologna (Italy); Department of Physics and Earth Sciences and CNISM, University of Ferrara, I-44122 Ferrara (Italy); Bonfiglioli, E.; Giovannini, L.; Spizzo, F.; Zivieri, R. [Department of Physics and Earth Sciences and CNISM, University of Ferrara, I-44122 Ferrara (Italy); Tamisari, M. [Department of Physics and Earth Sciences and CNISM, University of Ferrara, I-44122 Ferrara (Italy); Dipartimento di Fisica e Geologia, Università di Perugia, I-06123 Perugia (Italy)

    2015-05-07

    Brillouin light scattering (BLS) was exploited to study the spin wave properties of spin-valve (SV) type samples basically consisting of two 5 nm-thick NiFe layers (separated by a Cu spacer of 5 nm), differently biased through the interface exchange coupling with an antiferromagnetic IrMn layer. Three samples were investigated: a reference SV sample, without IrMn (reference); one sample with an IrMn underlayer (10 nm thick) coupled to the bottom NiFe film; one sample with IrMn underlayer and overlayer of different thickness (10 nm and 6 nm), coupled to the bottom and top NiFe film, respectively. The exchange coupling with the IrMn, causing the insurgence of the exchange bias effect, allowed the relative orientation of the NiFe magnetization vectors to be controlled by an external magnetic field, as assessed through hysteresis loop measurements by magneto-optic magnetometry. Thus, BLS spectra were acquired by sweeping the magnetic field so as to encompass both the parallel and antiparallel alignment of the NiFe layers. The BLS results, well reproduced by the presented theoretical model, clearly revealed the combined effects on the spin dynamic properties of the dipolar interaction between the two NiFe films and of the interface IrMn/NiFe exchange coupling.

  11. Tunneling Planar Hall Effect in Topological Insulators: Spin Valves and Amplifiers.

    Science.gov (United States)

    Scharf, Benedikt; Matos-Abiague, Alex; Han, Jong E; Hankiewicz, Ewelina M; Žutić, Igor

    2016-10-14

    We investigate tunneling across a single ferromagnetic barrier on the surface of a three-dimensional topological insulator. In the presence of a magnetization component along the bias direction, a tunneling planar Hall conductance (TPHC), transverse to the applied bias, develops. Electrostatic control of the barrier enables a giant Hall angle, with the TPHC exceeding the longitudinal tunneling conductance. By changing the in-plane magnetization direction, it is possible to change the sign of both the longitudinal and transverse differential conductance without opening a gap in the topological surface state. The transport in a topological-insulator-ferromagnet junction can, thus, be drastically altered from a simple spin valve to an amplifier.

  12. Pseudo spin-valve behavior in oxide ferromagnet/superconductor/ferromagnet trilayers

    International Nuclear Information System (INIS)

    Pang, B.S.H.; Bell, C.; Tomov, R.I.; Durrell, J.H.; Blamire, M.G.

    2005-01-01

    La 0.7 Ca 0.3 MnO 3 /YBa 2 Cu 3 O 7-δ /La 0.67 Sr 0.33 MnO 3 heterostructural devices with double coercivity have been fabricated. The superconducting critical current (I c ) and critical temperature in both parallel (P) and antiparallel (AP) magnetic configurations remained unchanged within our measurement limits. This observation is contrary to results obtained elsewhere using similar metallic systems. A pseudo spin-valve magnetoresistive (MR) characteristic was observed at bias current (I bias )∼I c at temperatures below the onset of superconductivity. The effect increased with decreasing temperature and I bias and can be explained using the assumption of the electron spin-charge separation

  13. Anomalous superconducting spin-valve effect in NbN/FeN/Cu/FeN/FeMn multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Tae Jong; Kim, Dong Ho [Yeungnam University, Gyeongsan (Korea, Republic of)

    2017-09-15

    We have studied magnetic and transport properties of NbN/FeN/Cu/FeN/FeMn spin-valve structure. In-plane magnetic moment exhibited typical hysteresis loops of spin valves in the normal state of NbN film at 20 K. On the other hand, the magnetic hysteresis loop in the superconducting state exhibited more complex behavior in which exchange bias provided by antiferrmagnetic FeMn layer to adjacent FeN layer was disturbed by superconductivity. Because of this, the ideal superconducting spin-valve effect was not detected. Instead the stray field originated from unsaturated magnetic states dominated the transport properties of NbN/FeN/Cu/FeN/FeMn multilayer.

  14. Spin-motive Force Induced by Domain Wall Dynamics in the Antiferromagnetic Spin Valve

    Science.gov (United States)

    Sugano, Ryoko; Ichimura, Masahiko; Takahashi, Saburo; Maekawa, Sadamichi; Crest Collaboration

    2014-03-01

    In spite of no net magnetization in antiferromagnetic (AF) textures, the local magnetic properties (Neel magnetization) can be manipulated in a similar fashion to ferromagnetic (F) ones. It is expected that, even in AF metals, spin transfer torques (STTs) lead to the domain wall (DW) motion and that the DW motion induces spin-motive force (SMF). In order to study the Neel magnetization dynamics and the resultant SMF, we treat the nano-structured F1/AF/F2 junction. The F1 and F2 leads behave as a spin current injector and a detector, respectively. Each F lead is fixed in the different magnetization direction. Torsions (DW in AF) are introduced reflecting the fixed magnetization of two F leads. We simulated the STT-induced Neel magnetization dynamics with the injecting current from F1 to F2 and evaluate induced SMF. Based on the adiabatic electron dynamics in the AF texture, Langevin simulations are performed at finite temperature. This research was supported by JST, CREST, Japan.

  15. Ultra-low-pressure sputtering to improve exchange bias and tune linear ranges in spin valves

    Energy Technology Data Exchange (ETDEWEB)

    Tang, XiaoLi, E-mail: tangtang1227@163.com; Yu, You; Liu, Ru; Su, Hua; Zhang, HuaiWu; Zhong, ZhiYong; Jing, YuLan

    2017-05-01

    A series of CoFe/IrMn exchange bilayers was grown by DC-sputtering at different ultra-low argon pressures ranging from 0.008 to 0.1 Pa. This pressure range was one to two orders lower than the normal sputtering pressure. Results revealed that the exchange bias increased from 140 to 250 Oe in CoFe(10 nm)/IrMn (15 nm) bilayers of fixed thickness because of the improved crystalline structure and morphological uniformity of films. Since ferromagnetic /antiferromagnetic (FM/AF) bilayers are always used in linear magnetic sensors as detection layers, the varying exchange bias can successfully achieve tunable linear range in a crossed pinning spin valve. The linear range could be adjustable from −80 Oe – +80 Oe to −150 Oe – +150 Oe on the basis of giant magnetoresistance responses. Therefore, this method provides a simple method to tune the operating range of magnetic field sensors. - Highlights: • Increasing exchange bias was achieved in bilayer at ultra-low-pressure sputtering. • The low void density and smooth surface were achieved in low pressure. • Varying exchange bias achieved tunable linear range in spin valve.

  16. Magnetic transport property of NiFe/WSe{sub 2}/NiFe spin valve structure

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Kangkang [Key Lab of Opto-electronics Technology, Ministry of Education, College of Electronic Information and Control Engineering, Beijing University of Technology, Beijing 100124 (China); Key Lab of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences (CAS), Suzhou 215123 (China); Xing, Yanhui, E-mail: xingyanhui@bjut.edu.cn [Key Lab of Opto-electronics Technology, Ministry of Education, College of Electronic Information and Control Engineering, Beijing University of Technology, Beijing 100124 (China); Han, Jun [Key Lab of Opto-electronics Technology, Ministry of Education, College of Electronic Information and Control Engineering, Beijing University of Technology, Beijing 100124 (China); Feng, Jiafeng [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences (CAS), Beijing 100190 (China); Shi, Wenhua; Zhang, Baoshun [Key Lab of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences (CAS), Suzhou 215123 (China); Zeng, Zhongming, E-mail: zmzeng2012@sinano.ac.cn [Key Lab of Nanodevices and Applications, Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences (CAS), Suzhou 215123 (China)

    2017-06-15

    Highlight: • Two-dimensional (2D) materials have been proposed as promising candidate for spintronic applications due to their atomic crystal structure and physical properties. • In this article, we introduce exfoliated few-layer tungsten diselenide (WSe{sub 2}) as spacer in a Py/WSe{sub 2}/Py vertical spin valve. • In this junction, the WSe{sub 2} spacer exhibits metallic behavior. • We observed negative magnetoresistance (MR) with a ratio of −1.1% at 4 K and −0.21% at 300 K. • A general phenomenological analysis of the negative MR property is discussed. • Our result is anticipated to be beneficial for future spintronic applications. - Abstract: Two-dimensional (2D) materials have been proposed as promising candidate for spintronic applications due to their atomic crystal structure and physical properties. Here, we introduce exfoliated few-layer tungsten diselenide (WSe{sub 2}) as spacer in a Py/WSe{sub 2}/Py vertical spin valve. In this junction, the WSe{sub 2} spacer exhibits metallic behavior. We observed negative magnetoresistance (MR) with a ratio of −1.1% at 4 K and −0.21% at 300 K. A general phenomenological analysis of the negative MR property is discussed. Our result is anticipated to be beneficial for future spintronic applications.

  17. High spin isomer beam line at RIKEN

    Energy Technology Data Exchange (ETDEWEB)

    Kishida, T.; Ideguchi, E.; Wu, H.Y. [Institute of Physical and Chemical Research, Saitama (Japan)] [and others

    1996-12-31

    Nuclear high spin states have been the subject of extensive experimental and theoretical studies. For the production of high spin states, fusion reactions are usually used. The orbital angular momentum brought in the reaction is changed into the nuclear spin of the compound nucleus. However, the maximum induced angular momentum is limited in this mechanism by the maximum impact parameter of the fusion reaction and by the competition with fission reactions. It is, therefore, difficult to populate very high spin states, and as a result, large {gamma}-detector arrays have been developed in order to detect subtle signals from such very high spin states. The use of high spin isomers in the fusion reactions can break this limitation because the high spin isomers have their intrinsic angular momentum, which can bring the additional angular momentum without increasing the excitation energy. There are two methods to use the high spin isomers for secondary reactions: the use of the high spin isomers as a target and that as a beam. A high spin isomer target has already been developed and used for several experiments. But this method has an inevitable shortcoming that only {open_quotes}long-lived{close_quotes} isomers can be used for a target: {sup 178}Hf{sup m2} (16{sup +}) with a half-life of 31 years in the present case. By developing a high spin isomer beam, the authors can utilize various short-lived isomers with a short half-life around 1 {mu}s. The high spin isomer beam line of RIKEN Accelerator Facility is a unique apparatus in the world which provides a high spin isomer as a secondary beam. The combination of fusion-evaporation reaction and inverse kinematics are used to produce high spin isomer beams; in particular, the adoption of `inverse kinematics` is essential to use short-lived isomers as a beam.

  18. Ultra-Compact 100 × 100 μm2 Footprint Hybrid Device with Spin-Valve Nanosensors

    Directory of Open Access Journals (Sweden)

    Diana C. Leitao

    2015-12-01

    Full Text Available Magnetic field mapping with micrometric spatial resolution and high sensitivity is a challenging application, and the technological solutions are usually based on large area devices integrating discrete magnetic flux guide elements. In this work we demonstrate a high performance hybrid device with improved field sensitivity levels and small footprint, consisting of a ultra-compact 2D design where nanometric spin valve sensors are inserted within the gap of thin-film magnetic flux concentrators. Pole-sensor distances down to 400 nm are demonstrated using nanofabrication techniques combined with an optimized liftoff process. These 100 × 100 μm 2 pixel sensors can be integrated in modular devices for surface mapping without moving parts.

  19. High energy spin isospin modes in nuclei

    International Nuclear Information System (INIS)

    Chanfray, G.; Ericson, M.

    1984-01-01

    The high energy response of nuclei to a spin-isospin excitation is investigated. We show the existence of a strong contrast between the spin transverse and spin longitudinal responses. The second one undergoes a shadow effect in the Δ region and displays the occurrence of the pionic branch

  20. High readmission rate after heart valve surgery

    DEFF Research Database (Denmark)

    Sibilitz, K L; Berg, S K; Thygesen, L C

    2015-01-01

    investigated. RESULTS: After valve surgery, the self-reported health was lower (Short Form-36 (SF-36) Physical Component Scale (PCS): 44.5 vs. 50.6 and Mental Component Scale (MCS): 51.9 vs. 55.0, pClinical signs......BACKGROUND: After heart valve surgery, knowledge on long-term self-reported health status and readmission is lacking. Thus, the optimal strategy for out-patient management after surgery remains unclear. METHODS: Using a nationwide survey with linkage to Danish registers with one year follow-up, we...... included all adults 6-12months after heart valve surgery irrespective of valve procedure, during Jan-June 2011 (n=867). Participants completed a questionnaire regarding health-status (n=742), and answers were compared with age- and sex-matched healthy controls. Readmission rates and mortality were...

  1. High-field spin dynamics of antiferromagnetic quantum spin chains

    DEFF Research Database (Denmark)

    Enderle, M.; Regnault, L.P.; Broholm, C.

    2000-01-01

    present recent work on the high-field spin dynamics of the S = I antiferromagnetic Heisenberg chains NENP (Haldane ground state) and CsNiCl3 (quasi-1D HAF close to the quantum critical point), the uniform S = 1/2 chain CTS, and the spin-Peierls system CuGeO3. (C) 2000 Elsevier Science B,V. All rights...

  2. Compressed gas domestic aerosol valve design using high viscous product

    Directory of Open Access Journals (Sweden)

    A Nourian

    2016-10-01

    Full Text Available Most of the current universal consumer aerosol products using high viscous product such as cooking oil, antiperspirants, hair removal cream are primarily used LPG (Liquefied Petroleum Gas propellant which is unfriendly environmental. The advantages of the new innovative technology described in this paper are: i. No butane or other liquefied hydrocarbon gas is used as a propellant and it replaced with Compressed air, nitrogen or other safe gas propellant. ii. Customer acceptable spray quality and consistency during can lifetime iii. Conventional cans and filling technology There is only a feasible energy source which is inert gas (i.e. compressed air to replace VOCs (Volatile Organic Compounds and greenhouse gases, which must be avoided, to improve atomisation by generating gas bubbles and turbulence inside the atomiser insert and the actuator. This research concentrates on using "bubbly flow" in the valve stem, with injection of compressed gas into the passing flow, thus also generating turbulence. The new valve designed in this investigation using inert gases has advantageous over conventional valve with butane propellant using high viscous product (> 400 Cp because, when the valving arrangement is fully open, there are negligible energy losses as fluid passes through the valve from the interior of the container to the actuator insert. The use of valving arrangement thus permits all pressure drops to be controlled, resulting in improved control of atomising efficiency and flow rate, whereas in conventional valves a significant pressure drops occurs through the valve which has a complex effect on the corresponding spray.

  3. Magnetism reflectometer study shows LiF layers improve efficiency in spin valve devices

    Energy Technology Data Exchange (ETDEWEB)

    Bardoel, Agatha A [ORNL; Lauter, Valeria [ORNL; Szulczewski, Greg J [ORNL

    2012-01-01

    New, more efficient materials for spin valves - a device used in magnetic sensors, random access memories, and hard disk drives - may be on the way based on research using the magnetism reflectometer at Oak Ridge National Laboratory (ORNL). Spin valve devices work by means of two or more conducting magnetic material layers that alternate their electrical resistance depending on the layers alignment. Giant magnetoresistance is a quantum mechanical effect first observed in thin film structures about 20 years ago. The effect is observed as a significant change in electrical resistance, depending on whether the magnetization of adjacent ferromagnetic layers is in a parallel or an antiparallel magnetic alignment. 'What we are doing here is developing new materials. The search for new materials suitable for injecting and transferring carriers with a preferential spin orientation is most important for the development of spintronics,' said Valeria Lauter, lead instrument scientist on the magnetism reflectometer at the Spallation Neutron Source (SNS), who collaborated on the experiment. The researchers discovered that the conductivity of such materials is improved when an organic polymer semiconductor layer is placed between the magnetic materials. Organic semiconductors are now the material of choice for future spin valve devices because they preserve spin coherence over longer times and distances than conventional semiconductors. While research into spin valves has been ongoing, research into organic semiconductors is recent. Previous research has shown that a 'conductivity mismatch' exists in spin valve systems in which ferromagnetic metal electrodes interface with such organic semiconductors as Alq3 ({pi}-conjugated molecule tris(8-hydroxy-quinoline) aluminium). This mismatch limits the efficient injection of the electrons from the electrodes at the interface with the semiconductor material. However, lithium fluoride (LiF), commonly used in light

  4. Biomolecule detection using wheatstone bridge giant magnetoresistance (GMR) sensors based on CoFeB spin-valve thin film

    Science.gov (United States)

    Elda Swastika, P.; Antarnusa, G.; Suharyadi, E.; Kato, T.; Iwata, S.

    2018-04-01

    A potential wheatstone bridge giant magnetoresistance (GMR) biosensor have been successfully developed for biomolecule detection. [IrMn(10 nm)/CoFe(3 nm)/Cu(2.2 nm)/CoFeB(10 nm)] spin-valve structure has been chosen as the magnetic sensing surface, showing a magnetoresistance (MR) of 6% fabricated by DC magnetron sputtering method. The Fe3O4 magnetic nanoparticles used as biomolecular labels (nanotags) was synthesized by co-precipitation method, exhibiting soft magnetic behavior with saturation magnetization (Ms), remanent magnetization (Mr) and coercivity (Hc) is 77.2 emu/g, 7.8 emu/g and 51 Oe, respectively. The X-ray diffraction (XRD) patterns and transmission electron microscopy (TEM) images showed that Fe3O4 was well crystallized and grew in their inverse spinel structure, highly uniform morphology with an average grain size was about 20 nm. Fe3O4 was coated with polyethylene-glycol (PEG)-4000 for surface functionalization. Detection of biomolecule such as formalin, gelatin from bovine-skin and porcine-skin were dispersed in ethanol at room temperature. Induction would cause a shift in output voltage with a minimum delta output voltage (ΔV) 4.937 mV (10%) for formalin detection, 2.268 mV (7%) for bovine-skin gelatin and 2.943 mV (7%) for porcine-skin gelatin detection. The ΔV of the wheatstone bridge in real-time measurement decrease by increase in biomolecules concentration. The change of ΔV with various concentration of biomolecule indicates that the spin-valve thin film with wheatstone-bridge circuit is potential as a biosensor.

  5. Abrupt relaxation in high-spin molecules

    International Nuclear Information System (INIS)

    Chang, C.-R.; Cheng, T.C.

    2000-01-01

    Mean-field model suggests that the rate of resonant quantum tunneling in high-spin molecules is not only field-dependent but also time-dependent. The relaxation-assisted resonant tunneling in high-spin molecules produces an abrupt magnetization change during relaxation. When the applied field is very close to the resonant field, a time-dependent interaction field gradually shifts the energies of different collective spin states, and magnetization tunneling is observed as two energies of the spin states coincide

  6. FERMILAB: High energy spin effects

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1991-03-15

    While many physicists would agree that it is important to study interactions of different isospin states (for example comparing proton and neutron data), many of them also accept as normal data averaged or integrated over ordinary spin. However an ongoing programme at Brookhaven studying elastic scattering (where the incoming particles 'bounce' off each other) produced marked spin effects which are not well understood. Our understanding of particle interactions should not be influenced by which observables are easy to measure and which aren't, and until a clear understanding of spin effects emerges, it is important to continue and extend these studies.

  7. Experimental status of high-spin states

    International Nuclear Information System (INIS)

    Stephens, F.S.

    1975-09-01

    Changes occurring in high spin nuclear states are discussed. Experimental methods for studying reduction and eventual quenching of pairing interactions, changes in nuclear shapes, and alignment of individual particle angular momenta with increasing spin are reviewed. Emphasis is placed on the study of continuum gamma rays following heavy ion reactions. (12 figures)

  8. The study of very high spin states

    International Nuclear Information System (INIS)

    Nolan, P.J.

    1992-01-01

    Some examples are given of the study of very high spin states that decay by discrete line gamma-ray emission. States up to spin 70(h/2π) have been seen in superdeformed bands. In other bands with normal deformation the limit is near 50(h/2π). (Author)

  9. Experimental investigation of the fluid dynamic efficiency of a high performance multi-valve internal combustion engine during the intake phase: Influence of valve-valve interference phenomena

    Directory of Open Access Journals (Sweden)

    Algieri Angelo

    2013-01-01

    Full Text Available The purpose of the present work is the analysis of the fluid dynamic behavior of a high performance internal combustion engine during the intake phase. In particular, a four-valve spark-ignition engine has been characterized at the steady flow rig. Dimensionless discharge coefficients have been used to define the global fluid dynamic efficiency of the intake system, while the Laser Doppler Anemometry (LDA technique has been employed to evaluate the mean flow in the valve curtain area and to characterise the interference phenomena between the two intake valves. The investigation has shown the significant influence of the valve lift on the volumetric efficiency of the intake apparatus. Moreover, the experimental analysis has highlighted that the valve-valve interference phenomena have a relevant impact on the head breathability, on the flow development within the combustion chamber and on the velocity standard deviations.

  10. Development of nuclear quality high pressure valve bellows in Canada

    International Nuclear Information System (INIS)

    Janzen, P.; Astill, C.J.

    1978-06-01

    Concurrent with the decision to use bellows stem sealed nuclear valves where feasible in commercial-scale CANDU plants, AECL undertook to develop an indigenous high pressure valve bellows technology. This program included developing the capability to fabricate improved high pressure valve bellows in conjunction with a Canadian manufacturer. This paper describes the evolution of a two-stage bellows fabrication process involving: (1) manufacture of discrete lengths of precision thin wall telescoping tubes - from preparation of strip blanks through edge grinding and edge forming to longitudinal welding; (2) forming of bellows from tube assemblies using a novel combination of mechanical inward forming followed by hydraulic outward forming. Bellows of Inconel 600 and Inconel 625 have been manufactured and evaluated. Test results indicate comparable to improved performance over alternative high quality bellows. (author)

  11. Nanostructures based on superconducting Nb and ferromagnetic CuNi alloy for elaboration of spin-valve core

    International Nuclear Information System (INIS)

    Morari, Roman

    2013-01-01

    The main goal of our research group is the elaboration of superconducting spin-switch (valve) based on Ferromagnetic/Superconductor/Ferromagnetic core. We could realize all building blocks necessary for the fabrication of the core structure of the superconducting spin valve, consisting of two mirror symmetric bilayers. In other words, the spin valve consists of a F/S * /F trilayer, which can be regarded as a package of a F/S and S/F bilayer so that S * =2S in the trilayer. For such a trilayer, the theory predicts that the critical temperature depends on the relative orientation of the magnetization of the ferromagnetic layers. To enable a reversal of one of the magnetizations of the layers with respect to the other by an external magnetic field, the coercive forces of the F layers have to be different due to either intrinsic properties or to an antiferromagnetic pinning layer delivering an exchange bias. The main points of our study are presented here. (author)

  12. Electric field-induced magnetoresistance in spin-valve/piezoelectric multiferroic laminates for low-power spintronics

    International Nuclear Information System (INIS)

    Huong Giang, D.T.; Thuc, V.N.; Duc, N.H.

    2012-01-01

    Electric field-induced magnetic anisotropy has been realized in the spin-valve-based {Ni 80 Fe 20 /Cu/Fe 50 Co 50 /IrMn}/piezoelectric multiferroic laminates. In this system, electric-field control of magnetization is accomplished by strain mediated magnetoelectric coupling. Practically, the magnetization in the magnetostrictive FeCo layer of the spin-valve structure rotates under an effective compressive stress caused by the inverse piezoelectric effect in external electrical fields. This phenomenon is evidenced by the magnetization and magnetoresistance changes under the electrical field applied across the piezoelectric layer. The result shows great potential for advanced low-power spintronic devices. - Highlights: ► Investigate electric field-induced magnetic anisotropy in spin-valve/piezoelectric. ► Magnetization, magnetoresistance changes under electric field across piezoelectric. ► Magnetization in magnetostrictive FeCo-layer rotates under a compressive stress. ► This advance shows great implications for low-power electronics and spintronics.

  13. High PT electronuclear reactions and spin observables

    International Nuclear Information System (INIS)

    Laget, J.M.

    1990-01-01

    The main arguments of the following topics are reviewed: the high transverse momentum exclusive reactions, the determination of various spin observables and the production of different flavours in reactions induced by real and virtual photons

  14. Thickness dependence of the triplet spin-valve effect in superconductor-ferromagnet heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Lenk, Daniel; Zdravkov, Vladimir I.; Kehrle, Jan; Obermeier, Guenther; Krug von Nidda, Hans-Albrecht; Mueller, Claus; Horn, Siegfried; Tidecks, Reinhard [Institut fuer Physik, Universitaet Augsburg (Germany); Morari, Roman [Institut fuer Physik, Universitaet Augsburg (Germany); D. Ghitsu Institute of Electronic Engineering and Nanotechnologies ASM, Kishinev (Moldova, Republic of); Sidorenko, Anatolie S. [D. Ghitsu Institute of Electronic Engineering and Nanotechnologies ASM, Kishinev (Moldova, Republic of); Tagirov, Lenar [Solid State Physics Department, Kazan Federal University (Russian Federation)

    2015-07-01

    We investigated the triplet spin-valve effect in nanoscale layered S/F{sub 1}/N/F{sub 2}/AF heterostructures with varying F{sub 1}-layer thickness (where S=Nb is a singlet superconducting, F{sub 1}=Cu{sub 41}Ni{sub 59} and F{sub 2}=Co a ferromagnetic, and N a normal-conducting, non-magnetic layer). The theory predicts a long-range, odd-in-frequency triplet component of superconductivity at non-collinear alignment of the magnetizations of F{sub 1} and F{sub 2}. This triplet component exhausts the singlet state and, thus, lowers the superconducting transition temperature, T{sub c}, yielding a global minimum of T{sub c} close to the perpendicular mutual orientations of the magnetizations. We found an oscillating decay of T{sub c} suppression, due to the generation of the triplet component, with increasing F{sub 1} layer thickness, which we discuss in the framework of recent theories.

  15. Investigations of the polymer/magnetic interface of organic spin-valves

    Energy Technology Data Exchange (ETDEWEB)

    Morley, N.A., E-mail: n.a.morley@sheffield.ac.uk [Department of Materials Science and Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom); Dost, R.; Lingam, A.S.V. [Department of Materials Science and Engineering, University of Sheffield, Mappin Street, Sheffield S1 3JD (United Kingdom); Barlow, A.J. [National EPSRC XPS Users’ Service, School of Mechanical and Systems Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU (United Kingdom)

    2015-12-30

    Graphical abstract: - Highlights: • Metal carbide and sulphide species are detected at a polymer–magnetic interface. • Top magnetic electrodes on P3HT have uniaxial anisotropy. • Top magnetic electrodes on PBTTT are isotropic. - Abstract: This work investigates the top interface of an organic spin-valve, to determine the interactions between the polymer and top magnetic electrode. The polymers studied are regio-regular poly(3-hexylthiophene) (RR-P3HT) and poly(2,5-bis(3-hexadecylthiophen-2-yl)thieno[3,2-b]thiophene (PBTTT) and the magnetic top electrodes are NiFe and Fe. X-ray photoelectron spectroscopy (XPS) is used to determine the bonding at the interface, along with the extent of how oxidised the magnetic layers are, while atomic force microscopy (AFM) is used to determine the surface roughness. A magneto-optic Kerr effect (MOKE) magnetometer is used to study the magnetic properties of the top electrode. It is shown that at the organic–magnetic interface the magnetic atoms interact with the polymer, as metallic–sulphide and metallic-carbide species are present at the interface. It is also shown that the structure of the polymer influences the anisotropy of the magnetic electrode, such that the magnetic electrodes grown on RR-P3HT have uniaxial anisotropy, while those grown on PBTTT are isotropic.

  16. Resistive Switching and Voltage Induced Modulation of Tunneling Magnetoresistance in Nanosized Perpendicular Organic Spin Valves

    Science.gov (United States)

    Schmidt, Georg; Goeckeritz, Robert; Homonnay, Nico; Mueller, Alexander; Fuhrmann, Bodo

    Resistive switching has already been reported in organic spin valves (OSV), however, its origin is still unclear. We have fabricated nanosized OSV based on La0.7Sr0.3MnO3/Alq3/Co. These devices show fully reversible resistive switching of up to five orders of magnitude. The magnetoresistance (MR) is modulated during the switching process from negative (-70%) to positive values (+23%). The results are reminiscent of experiments claiming magnetoelectric coupling in LSMO based tunneling structures using ferroelectric barriers. By analyzing the I/V characteristics of the devices we can show that transport is dominated by tunneling through pinholes. The resistive switching is caused by voltage induced creation and motion of oxygen vacancies at the LSMO surface, however, the resulting tunnel barrier is complemented by a second adjacent barrier in the organic semiconductor. Our model shows that the barrier in the organic material is constant, causing the initial MR while the barrier in the LMSO can be modulated by the voltage resulting in the resistive switching and the modulation of the MR as the coupling to the states in the LSMO changes. A switching caused by LSMO only is also supported by the fact that replacing ALQ3 by H2PC yields almost identical results. Supported by the DFG in the SFB762.

  17. Nanoscale magnetic characterization of tunneling magnetoresistance spin valve head by electron holography.

    Science.gov (United States)

    Park, Hyun Soon; Hirata, Kei; Yanagisawa, Keiichi; Ishida, Yoichi; Matsuda, Tsuyoshi; Shindo, Daisuke; Tonomura, Akira

    2012-12-07

    Nanostructured magnetic materials play an important role in increasing miniaturized devices. For the studies of their magnetic properties and behaviors, nanoscale imaging of magnetic field is indispensible. Here, using electron holography, the magnetization distribution of a TMR spin valve head of commercial design is investigated without and with a magnetic field applied. Characterized is the magnetic flux distribution in complex hetero-nanostructures by averaging the phase images and separating their component magnetic vectors and electric potentials. The magnetic flux densities of the NiFe (shield and 5 nm-free layers) and the CoPt (20 nm-bias layer) are estimated to be 1.0 T and 0.9 T, respectively. The changes in the magnetization distribution of the shield, bias, and free layers are visualized in situ for an applied field of 14 kOe. This study demonstrates the promise of electron holography for characterizing the magnetic properties of hetero-interfaces, nanostructures, and catalysts. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Ordinary and triplet superconducting spin valve effect in Fe/Pb based systems

    Energy Technology Data Exchange (ETDEWEB)

    Leksin, Pavel; Schumann, Joachim; Krupskaya, Yulia; Kataev, Vladislav; Hess, Christian; Schmidt, Oliver; Buechner, Bernd [Leibniz Institute for Solid State and Materials Research IFW Dresden (Germany); Garifyanov, Nadir; Garifullin, Ilgiz [Zavoisky Physical-Technical Institute of RAS, Kazan (Russian Federation); Fominov, Yakov [L. D. Landau Institute for Theoretical Physics of RAS, Moscow (Russian Federation)

    2015-07-01

    We report on experimental evidence for the occurrence of the long range triplet correlations (LRTC) of the superconducting (SC) condensate in the spin-valve heterostructures CoO{sub x}/Fe1/Cu/Fe2/Pb. The LRTC generation in this layer sequence is accompanied by a T{sub c} suppression near the orthogonal mutual orientation of the Fe1 and Fe2 layers' magnetization. This T{sub c} drop reaches its maximum of 60mK at the Fe2 layer thickness d{sub Fe2} = 0.6 nm and falls down when d{sub Fe2} is increased. The modification of the Fe/Pb interface by using a thin Cu layer between Fe and Pb layers reduces the SC transition width without preventing the interaction between Pb and Fe2 layers. The dependence of the SSVE magnitude on Fe1 layer thickness d{sub Fe1} reveals maximum of the effect when d{sub Fe1} and d{sub Fe2} are equal and the d{sub Fe2} value is minimal. Using the optimal d{sub Fe1}, d{sub Fe2} and the intermediate Cu layer we realized almost full switching from normal to SC state due to SSVE.

  19. Superconducting spin valves based on epitaxial Fe/V-hybrid thin film heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Nowak, Gregor

    2010-12-10

    This study presents a systematic investigation of the SSV effect in FM/SC/FM and FM/N/FM/SC heterostructures. Before investigating the actual SSV effect, we first pre-analyzed structural, magnetic and superconducting properties of the Fe/V system. In these preliminary studies we demonstrated, that epitaxial Fe/V heterostructures of superior crystalline quality can be grown by DC sputter deposition. With a Fe/V interface thickness of only one monolayer, the chemical separation of the Fe and V layers is extremely sharp. Moreover, the magnetic investigation showed that from thicknesses of two Fe(001) monolayers on the Fe layers in the superlattice possess a magnetic moment. Furthermore, we demonstrated the interlayer exchange coupling as oscillatory function of the V interlayer thickness. The investigations of the superconducting parameters of the Fe/V system revealed a non-monotonic T{sub S} vs. d{sub Fe} dependence in sample series (1). This observation proves the presence of the FM/SC proximity effect. The studies of various heterostructures of the design AFM/FM/SC/FM revealed a strong counteracting influence on the SSV effect, the stray field effect. The sample containing Fe{sub 25}V{sub 75} alloy layers, has the highest ratio of Cooper pair coherence length and superconductor thickness (ξ{sub S})/(d{sub S}), and its superconducting transition temperature is comparable to the sample with Fe{sub 35}V{sub 65} alloy layers. Nevertheless, the SSV effect in sample Fe{sub 25}V{sub 75} with alloy layers is much smaller than in sample with Fe{sub 35}V{sub 65} alloy layers. For a high-performance superconducting spin valve based on a FM1/SC/FM2 heterostructure at least four parameters have to be optimized simultaneously. 1. The magnetic domain size in FM1 and FM2 has to be as large as possible in order to reduce the stray field effect resulting from magnetization components in the FM domain walls perpendicular to the SC layer. 2. When using ferromagnetic alloys as

  20. Analysis of fatigue reliability for high temperature and high pressure multi-stage decompression control valve

    Science.gov (United States)

    Yu, Long; Xu, Juanjuan; Zhang, Lifang; Xu, Xiaogang

    2018-03-01

    Based on stress-strength interference theory to establish the reliability mathematical model for high temperature and high pressure multi-stage decompression control valve (HMDCV), and introduced to the temperature correction coefficient for revising material fatigue limit at high temperature. Reliability of key dangerous components and fatigue sensitivity curve of each component are calculated and analyzed by the means, which are analyzed the fatigue life of control valve and combined with reliability theory of control valve model. The impact proportion of each component on the control valve system fatigue failure was obtained. The results is shown that temperature correction factor makes the theoretical calculations of reliability more accurate, prediction life expectancy of main pressure parts accords with the technical requirements, and valve body and the sleeve have obvious influence on control system reliability, the stress concentration in key part of control valve can be reduced in the design process by improving structure.

  1. Spin-valves with modified synthetic antiferromagnets exhibiting an enhanced bias point control capability at submicrometer dimensions

    International Nuclear Information System (INIS)

    Park, J.-S.; Lee, S.-R.; Kim, Y.K.

    2004-01-01

    Bias point control is of practical importance for operating read sensors for magnetic recording and magnetic random access memory devices. To attain bias point control capability, in particular, at submicrometer cell size, a modified synthetic antiferromagnet-based spin-valve (MSSV) structure was devised. A series of calculations were carried out to investigate the effect of size variation on their MR transfer behaviors. The cell dimension was varied from 10 to 0.05 μm. The typical MSSV comprises IrMn (9.0)/CoFe (P1, 1.5)/Ru (0.7)/CoFe (P2, 3.0)/Ru (0.7)/CoFe (P3, 1.5)/Cu (2.8)/CoFe (1.6)/NiFe (3.2) (in nm). As the cell size decreased, the bias point in the MSSV maintained nearly zero regardless of the cell size. The bias point was further tuned by varying the P3 layer thickness. Moreover, the effective exchange field (H ex.eff ) of the MSSV was much larger than that of the conventional SSV. The field sensitivity of the MSSV was very high indicating that the free layer can rotate more sharply

  2. Spin-valves with modified synthetic antiferromagnets exhibiting an enhanced bias point control capability at submicrometer dimensions

    Science.gov (United States)

    Park, Jeong-Suk; Lee, Seong-Rae; Kim, Young Keun

    2004-08-01

    Bias point control is of practical importance for operating read sensors for magnetic recording and magnetic random access memory devices. To attain bias point control capability, in particular, at submicrometer cell size, a modified synthetic antiferromagnet-based spin-valve (MSSV) structure was devised. A series of calculations were carried out to investigate the effect of size variation on their MR transfer behaviors. The cell dimension was varied from 10 to 0.05 μm. The typical MSSV comprises IrMn (9.0)/CoFe (P1, 1.5)/Ru (0.7)/CoFe (P2, 3.0)/Ru (0.7)/CoFe (P3, 1.5)/Cu (2.8)/CoFe (1.6)/NiFe (3.2) (in nm). As the cell size decreased, the bias point in the MSSV maintained nearly zero regardless of the cell size. The bias point was further tuned by varying the P3 layer thickness. Moreover, the effective exchange field ( Hex.eff) of the MSSV was much larger than that of the conventional SSV. The field sensitivity of the MSSV was very high indicating that the free layer can rotate more sharply.

  3. Interplay between interface structure and magnetism in NiFe/Cu/Ni-based pseudo-spin valves

    Science.gov (United States)

    Loving, Melissa G.; Ambrose, Thomas F.; Ermer, Henry; Miller, Don; Naaman, Ofer

    2018-05-01

    Magnetic pseudo spin valves (PSVs) with superconducting Nb electrodes, have been leading candidates for an energy-efficient memory solution compatible with cryogenic operation of ultra-low power superconducting logic. Integration of these PSV Josephson junctions in a standard multi-layer Nb process requires growing high-quality thin magnetic films on a thick Nb bottom electrode (i.e. ≥1.5kÅ, to achieve bulk superconducting properties). However, as deposited, 1.5kÅ Nb exhibits a rough surface with a characteristic rice grain morphology, which severely degrades the switching properties of subsequently deposited PSVs. Therefore, in order to achieve coherent switching throughout a PSV, the Nb interface must be modified. Here, we demonstrate that the Nb surface morphology and PSV crystallinity can be altered with the incorporation of separate 50Å Cu or 100Å Al/50Å Cu non-magnetic seed layers, and demonstrate their impact on the magnetic switching of a 15Å Ni80Fe20/50Å Cu/20Å Ni PSV, at both room temperature and at 10 K. Most notably, these results show that the incorporation of an Al seed layer leads to an improved face centered cubic templating through the bulk of the PSV, and ultimately to superior magnetic switching.

  4. Research design and improvement of high temperature high pressure solenoid valve

    International Nuclear Information System (INIS)

    Luo Yongtang

    1987-12-01

    A process for development of the pilot type high temperature high pressure solenoid valve used in a PWR power plant is described. The whole development process might be divided into two phases: research design and improvement. In the former phase the questions had chiefly been approached in the following several aspects: the principle construction design, the determination of values for the constructionally key elements, the valve seal design and the solenoid actuator design, and made such valve's successful design in the main. In the latter phase an improvement had been made upon such valve against the problems during the testing use of the valve for a period of time, i.e. the unsatisfactory leak tightness, and achieved satisfactory results. The consummate success in this development not only has met the needs of the engineering project, but also made us obtain a valuable experience useful to design the similar valves

  5. Percutaneous implantation of the CoreValve aortic valve prosthesis in patients at high risk or rejected for surgical valve replacement: Clinical evaluation and feasibility of the procedure in the first 30 patients in the AMC-UvA

    NARCIS (Netherlands)

    Baan, J.; Yong, Z. Y.; Koch, K. T.; Henriques, J. P. S.; Bouma, B. J.; de Hert, S. G.; van der Meulen, J.; Tijssen, J. G. P.; Piek, J. J.; de Mol, B. A. J. M.

    2010-01-01

    Objective. To report the feasibility, safety and efficacy of percutaneous aortic valve implantation (PAVI) with the CoreValve self-expanding aortic valve bioprosthesis in elderly patients with aortic valve stenosis who are rejected for surgery or have a high surgical risk.Methods. PAVI using the

  6. High energy hadron spin-flip amplitude

    International Nuclear Information System (INIS)

    Selyugin, O.V.

    2016-01-01

    The high-energy part of the hadron spin-flip amplitude is examined in the framework of the new high-energy general structure (HEGS) model of the elastic hadron scattering at high energies. The different forms of the hadron spin-flip amplitude are compared in the impact parameter representation. It is shown that the existing experimental data of the proton-proton and proton-antiproton elastic scattering at high energy in the region of the diffraction minimum and at large momentum transfer give support in the presence of the energy-independent part of the hadron spin-flip amplitude with the momentum dependence proposed in the works by Galynskii-Kuraev. [ru

  7. Spin structure in high energy processes: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    DePorcel, L.; Dunwoodie, C. [eds.

    1994-12-01

    This report contains papers as the following topics: Spin, Mass, and Symmetry; physics with polarized Z{sup 0}s; spin and precision electroweak physics; polarized electron sources; polarization phenomena in quantum chromodynamics; polarized lepton-nucleon scattering; polarized targets in high energy physics; spin dynamics in storage rings and linear accelerators; spin formalism and applications to new physics searches; precision electroweak physics at LEP; recent results on heavy flavor physics from LEP experiments using 1990--1992 data; precise measurement of the left-right cross section asymmetry in Z boson production by electron-positron collisions; preliminary results on heavy flavor physics at SLD; QCD tests with SLD and polarized beams; recent results from TRISTAN at KEK; recent B physics results from CLEO; searching for the H dibaryon at Brookhaven; recent results from the compton observatory; the spin structure of the deuteron; spin structure of the neutron ({sup 3}HE) and the Bjoerken sum rule; a consumer`s guide to lattice QCD results; top ten models constrained by b {yields} sy; a review of the Fermilab fixed target program; results from the D0 experiment; results from CDF at FNAL; quantum-mechanical suppression of bremsstrahlung; report from the ZEUS collaboration at HERA; physics from the first year of H1 at HERA, and hard diffraction. These papers have been cataloged separately elsewhere.

  8. Spin structure in high energy processes: Proceedings

    International Nuclear Information System (INIS)

    DePorcel, L.; Dunwoodie, C.

    1994-12-01

    This report contains papers as the following topics: Spin, Mass, and Symmetry; physics with polarized Z 0 s; spin and precision electroweak physics; polarized electron sources; polarization phenomena in quantum chromodynamics; polarized lepton-nucleon scattering; polarized targets in high energy physics; spin dynamics in storage rings and linear accelerators; spin formalism and applications to new physics searches; precision electroweak physics at LEP; recent results on heavy flavor physics from LEP experiments using 1990--1992 data; precise measurement of the left-right cross section asymmetry in Z boson production by electron-positron collisions; preliminary results on heavy flavor physics at SLD; QCD tests with SLD and polarized beams; recent results from TRISTAN at KEK; recent B physics results from CLEO; searching for the H dibaryon at Brookhaven; recent results from the compton observatory; the spin structure of the deuteron; spin structure of the neutron ( 3 HE) and the Bjoerken sum rule; a consumer's guide to lattice QCD results; top ten models constrained by b → sy; a review of the Fermilab fixed target program; results from the D0 experiment; results from CDF at FNAL; quantum-mechanical suppression of bremsstrahlung; report from the ZEUS collaboration at HERA; physics from the first year of H1 at HERA, and hard diffraction. These papers have been cataloged separately elsewhere

  9. High spin studies with radioactive ion beams

    International Nuclear Information System (INIS)

    Garrett, J.D.

    1992-01-01

    The variety of new research possibilities afforded by the culmination of the two frontier areas of nuclear structure: high spin and studies far from nuclear stability (utilizing intense radioactive ion beams) are discussed. Topics presented include: new regions of exotic nuclear shape (e.g. superdeformation, hyperdeformation, and reflection-asymmetric shapes); the population of and consequences of populating exotic nuclear configurations; and complete spectroscopy (i.e. the overlap of state of the art low-and high-spin studies in the same nucleus)

  10. High spin spectroscopy of 70Ge

    International Nuclear Information System (INIS)

    Kumar Raju, M.; Sugathan, P.; Seshi Reddy, T.; Thirumala Rao, B.V.; Madhusudhana Rao, P.V.; Muralithar, S.; Singh, R.P.; Bhowmik, R.K.

    2011-01-01

    Structure of nuclei in mass 70 region is of interest due to presence of a variety of complex phenomenon. In these nuclei rapid change of nuclear shape with proton and neutron numbers, spin and excitation energy. Valance nucleons in f-p-g shell configuration will drive the nuclei towards high deformations. Relatively large values of quadrupole deformation are evident in the even-even nuclei in this region. Present study is aimed to explore the high spin structure of the 70 Ge nucleus. A negative parity structure was reported in an earlier study

  11. High spin studies with radioactive ion beams

    Energy Technology Data Exchange (ETDEWEB)

    Garrett, J D [Oak Ridge National Lab., TN (United States)

    1992-08-01

    The variety of new research possibilities afforded by the culmination of the two frontier areas of nuclear structure: high spin and studies far from nuclear stability (utilizing intense radioactive ion beams) are discussed. Topics presented include: new regions of exotic nuclear shape (e.g. superdeformation, hyperdeformation, and reflection-asymmetric shapes); the population of and consequences of populating exotic nuclear configurations; and, complete spectroscopy (i.e. the overlap of state of the art low- and high-spin studies in the same nucleus). (author). 47 refs., 8 figs.

  12. High spin structure in 130Ba

    International Nuclear Information System (INIS)

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

    2009-01-01

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

  13. Strong spin-filtering and spin-valve effects in a molecular V–C60–V contact

    Directory of Open Access Journals (Sweden)

    Mohammad Koleini

    2012-08-01

    Full Text Available Motivated by the recent achievements in the manipulation of C60 molecules in STM experiments, we study theoretically the structure and electronic properties of a C60 molecule in an STM tunneljunction with a magnetic tip and magnetic adatom on a Cu(111 surface using first-principles calculations. For the case of a vanadium tip/adatom, we demonstrate how spin coupling between the magnetic V atoms, mediated by the C60, can be observed in the electronic transport, which display a strong spin-filtering effect, allowing mainly majority-spin electrons to pass (>95%. Moreover, we find a significant change in the conductance between parallel and anti-parallel spin polarizations in the junction (86% which suggests that STM experiments should be able to characterize the magnetism and spin coupling for these systems.

  14. Strong spin-filtering and spin-valve effects in a molecular V-C-60-V contact

    DEFF Research Database (Denmark)

    Koleini, Mohammad; Brandbyge, Mads

    2012-01-01

    Motivated by the recent achievements in the manipulation of C-60 molecules in STM experiments, we study theoretically the structure and electronic properties of a C-60 molecule in an STM tunneljunction with a magnetic tip and magnetic adatom on a Cu(111) surface using first-principles calculations....... For the case of a vanadium tip/adatom, we demonstrate how spin coupling between the magnetic V atoms, mediated by the C-60, can be observed in the electronic transport, which display a strong spin-filtering effect, allowing mainly majority-spin electrons to pass (>95%). Moreover, we find a significant change...... in the conductance between parallel and anti-parallel spin polarizations in the junction (86%) which suggests that STM experiments should be able to characterize the magnetism and spin coupling for these systems....

  15. Chemical properties and GMR improvement of specular spin valves with nano-oxide layers, formed in ambient mixed gases

    International Nuclear Information System (INIS)

    Quang, H D; Hien, N T; Oh, S K; Sinh, N H; Yu, S C

    2004-01-01

    Specular spin valves (SVs) containing nano-oxide layers (NOLs) structured as substrate/seed/AF/P 1 /NOL/P 2 /Cu/F/NOL, have been fabricated. The NOLs were formed by natural oxidation in different ambient atmospheres of pure oxygen, oxygen/nitrogen and oxygen/argon gas mixtures. The fabrication conditions were optimized to enhance the magnetoresistance (MR) ratio, to suppress the interlayer coupling fields (H f ) between the free and pinned layers, to suppress the high interface density of the NOL, to ease the control of the NOL thickness and to form a smooth NOL/P 2 interface for promoting specular electron scattering. The characteristics of our specular SVs are the MR ratio of 14.1%, the exchange bias field of 44-45 mT, and H f weaker than 1.0 mT. The optimal conditions for oxidation time, total oxidation pressure and the annealing temperature were found to be 300 s, 0.14 Pa (oxygen/argon = 80/20) and 250 deg. C, respectively. Also, the origin of thermal stability of MMn-based (M = Fe, Pt, Ir, etc) specular SVs has been explained in detail by chemical properties of NOL using secondary-ion mass spectroscopy and x-ray photoelectron spectroscopy depth profile analyses. Thermal stability turns out to be caused by a decrease in MR ratios at high temperatures (>250 deg. C), which is a serious problem for device applications using the SV structure as a high density read head device

  16. High spin effects in superdense matter

    International Nuclear Information System (INIS)

    Bowers, R.L.; Gleeson, A.M.; Pedigo, R.D.

    1978-04-01

    A model of relativistic interacting superdense matter with vector, scalar and symmetric second rank tensor exchange is developed. The Green's functions of the model are solved in the self consistent Hartree approximation. The contributions of the symmetric second rank tensor are emphasized. It is found that these high spin contributions effect the superdense matter at densities just beyond those predicted to occur in neutron star matter or nuclear collisions. The spin-two effects do produce an unusual asymptotic dependence, p = - 1 / 3 epsilon. This effect is examined in a simple model of the early universe

  17. High spin structures in 194Hg

    International Nuclear Information System (INIS)

    Fotiades, N.; Vlastou, R.; Serris, M.; Sharpey-Schafer, J.F.; Fallon, P.; Riley, M.A.; Clark, R.M.; Hauschild, K.; Wadsworth, R.

    1996-01-01

    High spin states in the isotope 194 Hg were populated using the 150 Nd( 48 Ca,4n) reaction at a beam energy of 213 MeV. The analysis of γ-γ coincidences has revealed two new structures at excitation energies above 6 MeV and at moderate spin. The two structures are a manifestation of the deviation of nucleus from the collective rotation which dominates its lower excitation behaviour. A comparison with similar structures in the neighbouring Hg isotopes is also attempted. (orig.)

  18. Effect of uniaxial strain on the tunnel magnetoresistance of T-shaped graphene nanoribbon based spin-valve

    Science.gov (United States)

    Fouladi, A. Ahmadi

    2016-07-01

    We theoretically investigated the spin-dependent transport through a T-shaped graphene nanoribbon (TsGNR) based spin-valve consisting of armchair graphene sandwiched between two semi-infinite ferromagnetic armchair graphene nanoribbon leads in the presence of an applied uniaxial strain. Based on a tight-binding model and standard nonequilibrium Green's function technique, it is demonstrated that the tunnel magnetoresistance (TMR) for the system can be increased about 98% by tuning the uniaxial strain. Our results show that the absolute values of TMR around the zero bias voltage for compressive strain are larger than tensile strain. In addition, the TMR of the system can be nicely controlled by GNR width.

  19. High spin levels in 151Ho

    International Nuclear Information System (INIS)

    Gizon, J.; Gizon, A.; Andre, S.; Genevey, J.; Jastrzebski, J.; Kossakowski, R.; Moszinski, M.; Preibisz, Z.

    1981-02-01

    We report here on the first study of the level structure of 151 Ho. High spin levels in 151 Ho have been populated in the 141 Pr + 16 O and 144 Sm + 12 C reactions. The level structure has been established up to 6.6 MeV energy and the spins and particles determined up to 49/2 - . Most of the proposed level configurations can be explained by the coupling of hsub(11/2) protons to fsub(7/2) and/or hsub(9/2) neutrons. An isomer with 14 +- 3 ns half-life and a delayed gamma multiplicity equal to 17 +- 2 has been found. Its spin is larger than 57/2 h units

  20. High-spin states in 82Sr

    International Nuclear Information System (INIS)

    Baktash, C.; Halper, M.L.; Garcia Bermudez, G.J.

    1989-01-01

    As recent theoretical calculations that predicted the onset of superdeformation in the A ≅ 80 region, the 52 Cr( 34 S,2p2n) reaction at 130 MeV beam energy was employed to populate the high-spin states in 82 Sr. The detection system consisted of the ORNL Compton-Suppression Spectrometer System (18 Ge detectors), the Spin Spectrometer, and the 4 φ CsI Dwarf Ball of Washington University. Off-line analysis of the proton-gated data resulted in nearly 170 million Ge-Ge pairs, which were mostly due to the 2p2n channel. A decay scheme extending to spin I=27h has been established. No strong evidence for the presence of superdeformed states in 82 Sr was found in a preliminary analysis of the data. (Author) [es

  1. High Temperature Resistant Exhaust Valve Spindle

    DEFF Research Database (Denmark)

    Bihlet, Uffe Ditlev

    by experimental laser cladding. Heat treatments proved that these alloys were precipitation hardenable, and that some of them reached high levels of hardness. Based on these results, five Ni-based alloys containing 35-45 wt% Cr and 4-6 wt% Nb were ordered, to narrow down the feasible alloy compositions. During...

  2. Correlations between atomic structure and giant magnetoresistance ratio in Co2(Fe,Mn)Si spin valves

    International Nuclear Information System (INIS)

    Lari, L; Sizeland, J; Gilks, D; Uddin, G M; Nedelkoski, Z; Hasnip, P J; Lazarov, V K; Yoshida, K; Galindo, P L; Sato, J; Oogane, M; Ando, Y; Hirohata, A

    2014-01-01

    We show that the magnetoresistance of Co 2 Fe x Mn 1−x Si-based spin valves, over 70% at low temperature, is directly related to the structural ordering in the electrodes and at the electrodes/spacer (Co 2 Fe x Mn 1−x Si/Ag) interfaces. Aberration-corrected atomic resolution Z-contrast scanning transmission electron microscopy of device structures reveals that annealing at 350 °C and 500 °C creates partial B2/L2 1 and fully L2 1 ordering of electrodes, respectively. Interface structural studies show that the Ag/Co 2 Fe x Mn 1−x Si interface is more ordered compared to the Co 2 Fe x Mn 1−x Si/Ag interface. The release of interface strain is mediated by misfit dislocations that localize the strain around the dislocation cores, and the effect of this strain is assessed by first principles electronic structure calculations. This study suggests that by improving the atomic ordering and strain at the interfaces, further enhancement of the magnetoresistance of CFMS-based current-perpendicular-to-plane spin valves is possible. (fast track communication)

  3. Ferromagnetic resonance study of the half-Heusler alloy NiMnSb. The benefit of using NiMnSb as a ferromagnetic layer in pseudo-spin-valve based spin-torque oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Riegler, Andreas

    2011-11-25

    Since the discovery of spin torque in 1996, independently by Berger and Slonczewski, and given its potential impact on information storage and communication technologies, (e.g. through the possibility of switching the magnetic configuration of a bit by current instead of a magnetic field, or the realization of high frequency spin torque oscillators (STO)), this effect has been an important field of spintronics research. One aspect of this research focuses on ferromagnets with low damping. The lower the damping in a ferromagnet, the lower the critical current that is needed to induce switching of a spin valve or induce precession of its magnetization. In this thesis ferromagnetic resonance (FMR) studies of NiMnSb layers are presented along with experimental studies on various spin-torque (ST) devices using NiMnSb. NiMnSb, when crystallized in the half-Heusler structure, is a half-metal which is predicted to have 100% spin polarization, a consideration which further increases its potential as a candidate for memory devices based on the giant magnetoresistance (GMR) effect. The FMR measurements show an outstandingly low damping factor for NiMnSb, in low 10{sup -3} range. This is about a factor of two lower than permalloy and well comparable to lowest damping for iron grown by molecular beam epitaxy (MBE). According to theory the 100% spin polarization properties of the bulk disappear at interfaces where the break in translational symmetry causes the gap in the minority spin band to collapse but can remain in other crystal symmetries such as (111). Consequently NiMnSb layers on (111)(In,Ga)As buffer are characterized in respect of anisotropies and damping. The FMR measurements on these samples indicates a higher damping that for the 001 samples, and a thickness dependent uniaxial in-plane anisotropy. Investigations of the material for device use is pursued by considering sub-micrometer sized elements of NiMnSb on 001 substrates, which were fabricated by electron

  4. High-risk Trans-Catheter Aortic Valve Replacement in a Failed Freestyle Valve with Low Coronary Height: A Case Report

    OpenAIRE

    Karimi, Ashkan; Pourafshar, Negiin; Dibu, George; Beaver, Thomas M.; Bavry, Anthony A.

    2017-01-01

    A 55-year-old male with a history of two prior cardiac surgeries presented with decompensated heart failure due to severe bioprosthetic aortic valve insufficiency. A third operation was viewed prohibitively high risk and valve-in-valve trans-catheter aortic valve replacement was considered. There were however several high-risk features and technically challenging aspects including low coronary ostia height, poor visualization of the aortic sinuses, and difficulty in identification of the copl...

  5. Spin Filters as High-Performance Spin Polarimeters

    International Nuclear Information System (INIS)

    Rougemaille, N.; Lampel, G.; Peretti, J.; Drouhin, H.-J.; Lassailly, Y.; Filipe, A.; Wirth, T.; Schuhl, A.

    2003-01-01

    A spin-dependent transport experiment in which hot electrons pass through a ferromagnetic metal / semiconductor Schottky diode has been performed. A spin-polarized free-electron beam, emitted in vacuum from a GaAs photocathode, is injected into the thin metal layer with an energy between 5 and 1000 eV above to the Fermi level. The transmitted current collected in the semiconductor substrate increases with injection energy because of secondary - electron multiplication. The spin-dependent part of the transmitted current is first constant up to about 100 eV and then increases by 4 orders of magnitude. As an immediate application, the solid-state hybrid structure studied here leads to a very efficient and compact device for spin polarization detection

  6. Future directions for high-spin studies

    International Nuclear Information System (INIS)

    Stephens, F.S.

    1982-11-01

    Some future directions for experimental high-spin studies are discussed, concentrating mainly on the region above I -- 30h, where the γ-ray spectra are currently unresolvable. The 4π NaI balls offer a means to exploit the temperature effects recently shown to exist in such spectra. Large arrays of Compton-suppressed Ge detectors, on the other and, lead to higher effective resolution as it becomes possible to study triple and quadruple coincident events

  7. High-spin states in 60Cu

    International Nuclear Information System (INIS)

    Tsan, U.C.; Agard, M.; Bruandet, J.F.; Dauchy, A.; Giorni, A.; Glasser, F.; Morand, C.; Chambon, B.; Drain, D.

    1981-04-01

    The 60 Cu nucleus has been studied via the 58 Ni(α, pnγ) reaction using different in-beam γ spectroscopy techniques. As for the other odd-odd Cu, the gsub(9/2) shell plays an important role for the explanation of observed high-spin states. Some of them (in particular 6 - and 9 + states) could be interpreted as two-nucleon states in the framework of a crude shell model

  8. Transient flow characteristics of a high speed rotary valve

    Science.gov (United States)

    Browning, Patrick H.

    were experimentally mapped as a function of valve speed, inter-cylinder pressure ratios and volume ratios and the results were compared to compressible flow theoretical models. Specifically, the transient behavior suggested a short-lived loss-mode initiation closely resembled by shock tube theory followed by a quasi-steady flow regime resembling choked flow behavior. An empirical model was then employed to determine the useful range of the CCV design as applied to a four-stroke CIBAI engine cycle modeled using a 1-D quasi-steady numerical method, with particular emphasis on the cyclic timing of the CCV opening. Finally, a brief discussion of a high-temperature version of the CCV design is presented.

  9. Hydraulic High Pressure Valve Controller Using the In-Situ Pressure Difference

    Science.gov (United States)

    Bao, Xiaoqi (Inventor); Sherrit, Stewart (Inventor); Badescu, Mircea (Inventor); Bar-Cohen, Yoseph (Inventor); Hall, Jeffery L. (Inventor)

    2016-01-01

    A hydraulic valve controller that uses an existing pressure differential as some or all of the power source for valve operation. In a high pressure environment, such as downhole in an oil or gas well, the pressure differential between the inside of a pipe and the outside of the pipe may be adequately large to drive a linear slide valve. The valve is operated hydraulically by a piston in a bore. When a higher pressure is applied to one end of the bore and a lower pressure to the other end, the piston moves in response to the pressure differential and drives a valve attached to it. If the pressure differential is too small to drive the piston at a sufficiently high speed, a pump is provided to generate a larger pressure differential to be applied. The apparatus is conveniently constructed using multiport valves, which can be rotary valves.

  10. High spin states in 143Sm

    International Nuclear Information System (INIS)

    Raut, R.; Ganguly, S.; Kshetri, R.; Banerjee, P.; Bhattacharya, S.; Dasmahapatra, B.; Mukherjee, A.; Mukherjee, G.; Sarkar, M. Saha; Goswami, A.; Gangopadhyay, G.; Mukhopadhyay, S.; Krishichayan,; Chakraborty, A.; Ghughre, S. S.; Bhattacharjee, T.; Basu, S. K.

    2006-01-01

    The high spin states of 143 Sm have been studied by in-beam γ-spectroscopy following the reaction 130 Te( 20 Ne,7n) 143 Sm at E lab =137 MeV, using a Clover detector array. More than 50 new gamma transitions have been placed above the previously known J π =23/2 - , 30 ms isomer at 2795 keV. The level scheme of 143 Sm has been extended up to 12 MeV and spin-parity assignments have been made to most of the newly proposed level. Theoretical calculation with the relativistic mean field approach using blocked BCS method, has been performed. A sequence of levels connected by M1 transitions have been observed at an excitation energy ∼8.6 MeV. The sequence appears to be a magnetic rotational band from systematics

  11. Spin Hall magnetoresistance at high temperatures

    International Nuclear Information System (INIS)

    Uchida, Ken-ichi; Qiu, Zhiyong; Kikkawa, Takashi; Iguchi, Ryo; Saitoh, Eiji

    2015-01-01

    The temperature dependence of spin Hall magnetoresistance (SMR) in Pt/Y 3 Fe 5 O 12 (YIG) bilayer films has been investigated in a high temperature range from room temperature to near the Curie temperature of YIG. The experimental results show that the magnitude of the magnetoresistance ratio induced by the SMR monotonically decreases with increasing the temperature and almost disappears near the Curie temperature. We found that, near the Curie temperature, the temperature dependence of the SMR in the Pt/YIG film is steeper than that of a magnetization curve of the YIG; the critical exponent of the magnetoresistance ratio is estimated to be 0.9. This critical behavior of the SMR is attributed mainly to the temperature dependence of the spin-mixing conductance at the Pt/YIG interface

  12. High spin states of 141Pm

    Science.gov (United States)

    Bhattacharyya, Sarmishtha; Chanda, Somen; Bhattacharjee, Tumpa; Basu, Swapan Kumar; Bhowmik, R. K.; Muralithar, S.; Singh, R. P.; Ghugre, S. S.

    2004-01-01

    The high spin states in the N=80 odd- A141Pm nucleus have been investigated by in-beam γ-spectroscopic techniques following the reaction 133Cs( 12C, 4n) 141Pm at E=65 MeV using a modest γ detector array, consisting of seven Compton-suppressed high purity germanium detectors and a multiplicity ball of 14 bismuth germanate elements. Thirty new γ rays have been assigned to 141Pm on the basis of γ-ray singles and γγ-coincidence data. The level scheme of 141Pm has been extended upto an excitation energy of 5.2 MeV and spin {35}/{2}ℏ and 16 new levels have been proposed. Spin-parity assignments for most of the newly proposed levels have been made on the basis of the deduced directional correlation orientation ratios for strong transitions. The meanlives of a few excited states have been determined from the pulsed beam- γγ coincidence data using the generalised centroid-shift method. The level structure is discussed in the light of known systematics of neighbouring N=80 isotonic nuclei.

  13. 16th Workshop on High Energy Spin Physics

    CERN Document Server

    2016-01-01

    The Workshop will cover a wide range of spin phenomena at high and intermediate energies such as: recent experimental data on spin physics the nucleon spin structure and GPD's spin physics and QCD spin physics in the Standard Model and beyond T-odd spin effects polarization and heavy ion physics spin in gravity and astrophysics the future spin physics facilities spin physics at NICA polarimeters for high energy polarized beams acceleration and storage of polarized beams the new polarization technology related subjects The Workshop will be held in the Bogoliubov Laboratory of Theoretical Physics of the Joint Institute for Nuclear Research, 141980 Dubna, Moscow Region, Russia. The program of the workshop will include plenary and parallel (if necessary) sessions. Plenary sessions will be held in the Conference Hall. Parallel sections will take place in the same building. There will be invited talks (up to 40 min) and original reports (20 min). The invited speakers will present new experimental and theoretical re...

  14. Evolution of nuclear shapes at high spins

    International Nuclear Information System (INIS)

    Johnson, N.R.

    1985-01-01

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

  15. Electromagnetic properties of nuclei at high spins

    International Nuclear Information System (INIS)

    Leander, G.A.

    1986-01-01

    A photon emitted by an excited state is likely to carry away, at most, 1 or 2 h-bar of angular momentum. Therefore, a profusion of photons is needed to deexcite the rapidly rotating states of nuclei formed by heavy-ion reactions. The study of electromagnetic properties has become the primary source of information on nuclear structure at high spins and, also, at the warm temperatures present in the initial stage of the electromagnetic cascade process. The purpose of this paper is a review of the E1, M1, and E2 properties of such highly excited states. 42 refs., 5 figs

  16. Nuclear moments of inertia at high spin

    International Nuclear Information System (INIS)

    Deleplanque, M.A.

    1982-10-01

    The competition between collective motion and alignment at high spin can be evaluated by measuring two complementary dynamic moments of inertia. The first, I band, measured in γ-γ correlation experiments, relates to the collective properties of the nucleus. A new moment of inertia I/sub eff/ is defined here, which contains both collective and alignment effects. Both of these can be measured in continuum γ-ray spectra of rotational nuclei up to high frequencies. The evolution of γ-ray spectra for Er nuclei from mass 160 to 154 shows that shell effects can directly be observed in the spectra of the lighter nuclei

  17. High-risk Trans-Catheter Aortic Valve Replacement in a Failed Freestyle Valve with Low Coronary Height: A Case Report.

    Science.gov (United States)

    Karimi, Ashkan; Pourafshar, Negiin; Dibu, George; Beaver, Thomas M; Bavry, Anthony A

    2017-06-01

    A 55-year-old male with a history of two prior cardiac surgeries presented with decompensated heart failure due to severe bioprosthetic aortic valve insufficiency. A third operation was viewed prohibitively high risk and valve-in-valve trans-catheter aortic valve replacement was considered. There were however several high-risk features and technically challenging aspects including low coronary ostia height, poor visualization of the aortic sinuses, and difficulty in identification of the coplanar view due to severe aortic insufficiency, and a highly mobile aortic valve mass. After meticulous peri-procedural planning, trans-catheter aortic valve replacement was carried out with a SAPIEN 3 balloon-expandable valve without any complication. Strategies undertaken to navigate the technically challenging aspects of the case are discussed.

  18. Identification of high-spin states in 235U

    International Nuclear Information System (INIS)

    Lorenz, A.; Makarenko, V.E.; Chukreev, F.E.

    1994-02-01

    The results of a 235 U high spin states study are analysed. A new way to assign newly observed gamma ray transitions is proposed. Such assignments deals with low spin parts of the level scheme without introducing high spin level states. (author)

  19. Effect of NiAl underlayer and spacer on magnetoresistance of current-perpendicular-to-plane spin valves using Co2Mn(Ga0.5Sn0.5) Heusler alloy

    International Nuclear Information System (INIS)

    Hase, N.; Nakatani, T.M.; Kasai, S.; Takahashi, Y.K.; Furubayashi, T.; Hono, K.

    2012-01-01

    We investigated the effect of a NiAl underlayer and spacer on magnetoresistive (MR) properties in current-perpendicular-to-plane spin valves (CPP-SVs) using Co 2 Mn(Ga 0.5 Sn 0.5 ) (CMGS) Heusler alloy ferromagnetic layers. The usage of a NiAl underlayer allowed a high temperature annealing for the L2 1 ordering of the bottom CMGS layer, giving rise to a MR ratio of 10.2% at room temperature. We found that the usage of a NiAl spacer layer also improved the tolerance of the multilayer structure against thermal delamination, which allowed annealing to induce the L2 1 structure in both the bottom and top CMGS layers. However, the short spin diffusion length of NiAl resulted in a lower MR ratio compared to that obtained using a Ag spacer. Transmission electron microscopy of the multilayer structure of CPP-SVs showed that the atomically flat layered structure was maintained after the annealing. - Highlights: → CPP spin valves using Co 2 Mn(Ga 0.5 Sn 0.5 ) ferromagnetic layers with a new underlayer material. → NiAl underlayer and spacer improve the thermal tolerance of the spin valve structure. → NiAl underlayer improves MR ratio compared to Ag because of higher annealing temperature. → NiAl spacer degrades MR ratios compared to Ag because of short spin diffusion length. → Potential of heat resistant underlayer and spacer layer for CPP-SV using Heusler alloy.

  20. Performance of current-in-plane pseudo-spin-valve devices on CMOS silicon-on-insulator underlayers

    Science.gov (United States)

    Katti, R. R.; Zou, D.; Reed, D.; Schipper, D.; Hynes, O.; Shaw, G.; Kaakani, H.

    2003-05-01

    Prior work has shown that current-in-plane (CIP) giant magnetoresistive (GMR) pseudo-spin-valve (PSV) devices grown on bulk Si wafers and bulk complementary metal-oxide semiconductor (CMOS) underlayers exhibit write and read characteristics that are suitable for application as nonvolatile memory devices. In this work, CIP GMR PSV devices fabricated on silicon-on-insulator CMOS underlayers are shown to support write and read performance. Reading and writing fields for selected devices are shown to be approximately 25%-50% that of unselected devices, which provides a margin for reading and writing specific bits in a memory without overwriting bits and without disturbing other bits. The switching characteristics of experimental devices were compared to and found to be similar with Landau-Lifschitz-Gilbert micromagnetic modeling results, which allowed inferring regions of reversible and irreversible rotations in magnetic reversal processes.

  1. High spin-filter efficiency and Seebeck effect through spin-crossover iron–benzene complex

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Qiang; Zhou, Liping, E-mail: zhoulp@suda.edu.cn; Cheng, Jue-Fei; Wen, Zhongqian; Han, Qin; Wang, Xue-Feng [College of Physics, Optoelectronics and Energy and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006 (China)

    2016-04-21

    Electronic structures and coherent quantum transport properties are explored for spin-crossover molecule iron-benzene Fe(Bz){sub 2} using density functional theory combined with non-equilibrium Green’s function. High- and low-spin states are investigated for two different lead-molecule junctions. It is found that the asymmetrical T-shaped contact junction in the high-spin state behaves as an efficient spin filter while it has a smaller conductivity than that in the low-spin state. Large spin Seebeck effect is also observed in asymmetrical T-shaped junction. Spin-polarized properties are absent in the symmetrical H-shaped junction. These findings strongly suggest that both the electronic and contact configurations play significant roles in molecular devices and metal-benzene complexes are promising materials for spintronics and thermo-spintronics.

  2. High spin spectroscopy of 34Cl

    International Nuclear Information System (INIS)

    Bisoi, Abhijit; Ray, S.; Kshetri, R.; Goswami, A.; Saha Sarkar, M.; Pramanik, D.; Sarkar, S.; Nag, S.; Selva Kumar, K.; Singh, P.; Saha, S.; Sethi, J.; Trivedi, T.; Naidu, B.S.; Donthi, R.; Nanal, V.; Palit, R.

    2011-01-01

    Spectroscopic information for 34 Cl is of interest for understanding the large 33 S abundance observed in nova. This nucleus has been extensively studied using proton, light ions and alpha beams but there are few experiments where heavy ions were used. In the present work, heavy ion beams are used to extract spectroscopic data for high spin states above ∼ 5 MeV, important for astrophysical scenario. Spherical shell model calculations have been done to interpret the experimental data. Several options of truncation adopted have provided useful insight into the sd - fp cross-shell calculations

  3. Physics of high spin nuclear states

    Energy Technology Data Exchange (ETDEWEB)

    Wyss, R [Joint Inst. for Heavy Ion Research, Oak Ridge, TN (United States); [MSI, Frescativ, Stockholm (Sweden)

    1992-08-01

    High spin physics is a vast topic addressing the variety of nuclear excitation modes. In the present paper, some general aspects related to recent highlights of nuclear spectroscopy are discussed. The relation between signature splitting and shape changes in the unique parity orbitals is elucidated. The relevance of the Pseudo SU(3) symmetry in the understanding of rotational band structure is addressed. Specific features of rotational bands of intruder configurations are viewed as a probe of the neutron-proton interaction. (author). 36 refs., 5 figs.

  4. Spin crossover and high spin filtering behavior in Co-Pyridine and Co-Pyrimidine molecules

    Science.gov (United States)

    Wen, Zhongqian; Zhou, Liping; Cheng, Jue-Fei; Li, Shu-Jin; You, Wen-Long; Wang, Xuefeng

    2018-03-01

    We present a theoretical study on a series of cobalt complexes, which are constructed with cobalt atoms and pyridine/pyrimidine rings, using density functional theory. We investigate the structural and electric transport properties of spin crossover (SCO) Co complex with two spin states, namely low-spin configuration [LS] and high-spin configuration [HS]. Energy analyses of the two spin states imply that the SCO Co-Pyridine2 and Co-Pyrimidine2 complexes may display a spin transition process accompanied by a geometric modification driven by external stimuli. A nearly perfect spin filtering effect is observed in the Co-Pyrimidine2 complex with [HS] state. In addition, we also discover the contact-dependent transmission properties of Co-Pyridine2. These findings indicate that SCO Co complexes are promising materials for molecular spintronic devices.

  5. Nuclear moments of inertia at high spins

    International Nuclear Information System (INIS)

    Deleplanque, M.A.

    1984-01-01

    For nuclei in high spin states a yrast-like part of a continuum γ-ray spectrum shows naturally how angular momentum is generated as a function of frequency. In rotational nuclei, the rotational frequency is omega = dE/dI approx. E/sub γ/2, half the collective E2 transition energy. The height of the spectrum for a rotor is proportional to dN/dE/sub γ/ = dI/4d omega. dI/d omega is a dynamic (second derivative of energy with spin) moment of inertia. It contains both alignments and collective effects and is therefore an effective moment of inertia J/sub eff//sup (2)/. It shows how much angular momentum is generated at each frequency. If the collective moment of inertia J/sub band//sup (2)/(omega) is measured (from γ-γ correlation experiments) for the same system, the collective and aligned (Δi) contributions to the increase of angular momentum ΔI in a frequency interval Δ omega can be separated: Δi/ΔI = 1 - J/sub band//sup (2)//J/sub eff//sup (2)/. This is at present the only way to extract such detailed information at the highest spin states where discrete lines cannot be resolved. An example of the spectra obtained in several Er nuclei is shown. They are plotted in units of the moment of inertia J/sub eff//sup (2)/. The high-energy part of the spectra has been corrected for incomplete feeding at these frequencies

  6. Quantum interference effect in electron tunneling through a quantum-dot-ring spin valve.

    Science.gov (United States)

    Ma, Jing-Min; Zhao, Jia; Zhang, Kai-Cheng; Peng, Ya-Jing; Chi, Feng

    2011-03-28

    Spin-dependent transport through a quantum-dot (QD) ring coupled to ferromagnetic leads with noncollinear magnetizations is studied theoretically. Tunneling current, current spin polarization and tunnel magnetoresistance (TMR) as functions of the bias voltage and the direct coupling strength between the two leads are analyzed by the nonequilibrium Green's function technique. It is shown that the magnitudes of these quantities are sensitive to the relative angle between the leads' magnetic moments and the quantum interference effect originated from the inter-lead coupling. We pay particular attention on the Coulomb blockade regime and find the relative current magnitudes of different magnetization angles can be reversed by tuning the inter-lead coupling strength, resulting in sign change of the TMR. For large enough inter-lead coupling strength, the current spin polarizations for parallel and antiparallel magnetic configurations will approach to unit and zero, respectively.PACS numbers:

  7. Quantum interference effect in electron tunneling through a quantum-dot-ring spin valve

    Directory of Open Access Journals (Sweden)

    Ma Jing-Min

    2011-01-01

    Full Text Available Abstract Spin-dependent transport through a quantum-dot (QD ring coupled to ferromagnetic leads with noncollinear magnetizations is studied theoretically. Tunneling current, current spin polarization and tunnel magnetoresistance (TMR as functions of the bias voltage and the direct coupling strength between the two leads are analyzed by the nonequilibrium Green's function technique. It is shown that the magnitudes of these quantities are sensitive to the relative angle between the leads' magnetic moments and the quantum interference effect originated from the inter-lead coupling. We pay particular attention on the Coulomb blockade regime and find the relative current magnitudes of different magnetization angles can be reversed by tuning the inter-lead coupling strength, resulting in sign change of the TMR. For large enough inter-lead coupling strength, the current spin polarizations for parallel and antiparallel magnetic configurations will approach to unit and zero, respectively. PACS numbers:

  8. A high performance magnetorheological valve with a meandering flow path

    International Nuclear Information System (INIS)

    Imaduddin, Fitrian; Amri Mazlan, Saiful; Azizi Abdul Rahman, Mohd; Zamzuri, Hairi; Ubaidillah; Ichwan, Burhanuddin

    2014-01-01

    The huge developments in the field of magnetorheological (MR) fluid-based devices will have a great influence on the future of mechatronic applications due to the ease of interfacing between electronic controls and the mechanical components that they provide. Among various MR fluid-based devices, an MR valve would be particularly significant for the development of other devices, if it could be successfully achieved. One of the most challenging obstacles to MR valve development is the difficulty of achieving device miniaturization while, at the same time, improving the achievable performance. This study demonstrates a novel design for an MR valve, using the meandering flow path approach in order to increase the effective area so that the MR fluid can be regulated within a small-sized valve. The meandering flow path is formed by combining multiple annular, radial and orifice flow channels. In order to analyze the valve performance, a mathematical model of the proposed MR valve is derived and combined with numerical simulation using the finite element method, with the intention of predicting the achievable pressure drop that can be generated by the valve. The predicted MR valve performances are then experimentally evaluated using an oscillation-disturbed bypass hydraulic cylinder. The simulation results show that the proposed MR valve design could yield substantial pressure drop improvement, which is confirmed by the experiment

  9. Spin effects in high energy quark-quark scattering

    International Nuclear Information System (INIS)

    Goloskokov, S.V.; Selyugin, O.V.

    1993-01-01

    The spin amplitudes in high-energy quark-quark scattering at /t/>1 GeV 2 are analyzed. It is shown that the gluon contributions in the QCDα s 3 order lead to the spin-flip amplitude growing as s. This means the existence of the spin-flip part in pomeron exchange. The resulting T f is about few per cent of the spin-non-flip contribution. The factorization of the large-distance and high-energy effects in the spin-flip amplitude is obtained. 13 refs.; 2 figs.; 1 tab

  10. Absence of hyperfine effects in 13C-graphene spin-valve devices

    NARCIS (Netherlands)

    Wojtaszek, M.; Vera-Marun, I.J.; Whiteway, E.; Hilke, M.; Wees, B.J. van

    2014-01-01

    The carbon isotope 13C, in contrast to 12C, possesses a nuclear magnetic moment and can induce electron spin dephasing in graphene. This effect is usually neglected due to the low abundance of 13C in natural carbon allotropes (~1%). Chemical vapor deposition (CVD) allows for artificial synthesis of

  11. A comparison of conventional surgery, transcatheter aortic valve replacement, and sutureless valves in "real-world" patients with aortic stenosis and intermediate- to high-risk profile.

    Science.gov (United States)

    Muneretto, Claudio; Alfieri, Ottavio; Cesana, Bruno Mario; Bisleri, Gianluigi; De Bonis, Michele; Di Bartolomeo, Roberto; Savini, Carlo; Folesani, Gianluca; Di Bacco, Lorenzo; Rambaldini, Manfredo; Maureira, Juan Pablo; Laborde, Francois; Tespili, Maurizio; Repossini, Alberto; Folliguet, Thierry

    2015-12-01

    We sought to investigate the clinical outcomes of patients with isolated severe aortic stenosis and an intermediate- to high-risk profile treated by means of conventional surgery (surgical aortic valve replacement), sutureless valve implantation, or transcatheter aortic valve replacement in a multicenter evaluation. Among 991 consecutive patients with isolated severe aortic stenosis and an intermediate- to high-risk profile (Society of Thoracic Surgeons score >4 and logistic European System for Cardiac Operative Risk Evaluation I >10), a propensity score analysis was performed on the basis of the therapeutic strategy: surgical aortic valve replacement (n = 204), sutureless valve implantation (n = 204), and transcatheter aortic valve replacement (n = 204). Primary end points were 30-day mortality and overall survival at 24-month follow-up; the secondary end point was survival free from a composite end point of major adverse cardiac events (defined as cardiac-related mortality, myocardial infarction, cerebrovascular accidents, and major hemorrhagic events) and periprosthetic regurgitation greater than 2. Thirty-day mortality was significantly higher in the transcatheter aortic valve replacement group (surgical aortic valve replacement = 3.4% vs sutureless = 5.8% vs transcatheter aortic valve replacement = 9.8%; P = .005). The incidence of postprocedural was 3.9% in asurgical aortic valve replacement vs 9.8% in sutureless vs 14.7% in transcatheter aortic valve replacement (Prisk factor for overall mortality hazard ratio (hazard ratio, 2.5; confidence interval, 1.1-4.2; P = .018). The use of transcatheter aortic valve replacement in patients with an intermediate- to high-risk profile was associated with a significantly higher incidence of perioperative complications and decreased survival at short- and mid-term when compared with conventional surgery and sutureless valve implantation. Copyright © 2015 The American Association for Thoracic Surgery. Published by

  12. High-spin excitations of atomic nuclei

    International Nuclear Information System (INIS)

    Xu Furong; National Laboratory of Heavy Ion Physics, Lanzhou; Chinese Academy of Sciences, Beijing

    2004-01-01

    The authors used the cranking shell model to investigate the high-spin motions and structures of atomic nuclei. The authors focus the collective rotations of the A∼50, 80 and 110 nuclei. The A∼50 calculations show complicated g spectroscopy, which can have significant vibration effects. The A≅80 N≅Z nuclei show rich shape coexistence with prolate and oblate rotational bands. The A≅110 nuclei near the r-process path can have well-deformed oblate shapes that become yrast and more stable with increasing rotational frequency. As another important investigation, the authors used the configuration-constrained adiabatic method to calculate the multi-quasiparticle high-K states in the A∼130, 180 and superheavy regions. The calculations show significant shape polarizations due to quasi-particle excitations for soft nuclei, which should be considered in the investigations of high-K states. The authors predicted some important high-K isomers, e.g., the 8 - isomers in the unstable nuclei of 140 Dy and 188 Pb, which have been confirmed in experiments. In superheavy nuclei, our calculations show systematic existence of high-K states. The high-K excitations can increase the productions of synthesis and the survival probabilities of superheavy nuclei. (authors)

  13. Magnetotransport in spin-valve systems with amorphous magnetic and superconducting partial layers; Magnetotransport in Spinventil-Systemen mit amorphen magnetischen und supraleitenden Teilschichten

    Energy Technology Data Exchange (ETDEWEB)

    Steiner, Roland Johannes

    2006-04-27

    The first part of this work deals with the fabrication and characterisation of spin valves with an amorphous FeB layer acting as a weak ferromagnet embedded into the structure. In the second part of this work ferromagnet/superconductor hybrid structures are fabricated and the relevant magnetic field dependent transport phenomena are analyzed. The interlayer of a conventional spin valve was replaced by a superconducting niobium layer. Small applied fields close to the coercivity field of the involved ferromagnets - and thus far below the critical magnetic field of the superconductor - affected the critical temperature of the niobium layer. Measurements of the field dependent resistance and the critical temperature of a FM/SC/FMsystem showed a local maximum in the T{sub c}(H)- and the R(H)-curve. (orig.)

  14. Interfacial spectroscopic characterization of organic/ferromagnet hetero-junction of 3,4,9,10-perylene-teracarboxylic dianhydride-based organic spin valves

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Jhen-Yong; Ou Yang, Kui-Hon; Li, Kai-Shin [Department of Physics, National Taiwan University, 10617 Taipei, Taiwan (China); Wang, Bo-Yao [Department of Physics, National Taiwan University, 10617 Taipei, Taiwan (China); Department of Physics, National Changhua University of Education, Changhua 500, Taiwan (China); Shiu, Hung-Wei; Chen, Chia-Hao; Chan, Yuet-Loy; Wei, Der-Hsin; Chang, Fan-Hsiu; Lin, Hong-Ji [National Synchrotron Radiation Research Center, 30076 Hsinchu, Taiwan (China); Chiang, Wen-Chung, E-mail: wchiang@faculty.pccu.edu.tw [Department of Physics, Chinese Culture University, 11114 Taipei, Taiwan (China); Lin, Minn-Tsong, E-mail: mtlin@phys.ntu.edu.tw [Department of Physics, National Taiwan University, 10617 Taipei, Taiwan (China); Institute of Atomic and Molecular Sciences, Academia Sinica, 10617 Taipei, Taiwan (China)

    2014-02-24

    We report interfacial characterization of 3,4,9,10-perylene-teracarboxylic dianhydride (PTCDA)-based organic spin valves (OSV) dusted with a thin layer of partially oxidized alumina at the organic semiconductor (OSC)/ferromagnet (FM) interfaces. Up to 13.5% magnetoresistance is achieved at room temperature. X-ray photoelectron spectroscopy measurements reveal interfacial electronic interaction between PTCDA and FM while the application of a thin alumina layer at the PTCDA/FM interfaces prevents the electronic hybridization and effectively preserves the spin injection into the OSC spacer. This finding demonstrates the critical effect of interfacial structure on magnetotransport behavior in OSV.

  15. Yrast and high spin states in 22Ne

    International Nuclear Information System (INIS)

    Szanto, E.M.; Toledo, A.S. de

    1982-08-01

    High spin states in 22 Ne have been investigated by the reactions 11 B( 13 C,d) 22 Ne and 13 C( 11 B,d) 22 Ne up to E* approximately=19 MeV. Yrast states were observed at 11.02 MeV (8 + ) and 15.46 MeV (10 + ) excitation energy. A backbending in 22 Ne is observed around spin 8 + . The location of high spin states I [pt

  16. SPIN SUSCEPTIBILITY IN HIGH - TC SUPERCONDUCTIVITY

    African Journals Online (AJOL)

    USER

    2012-07-05

    Jul 5, 2012 ... remains unchanged as a result of which the oxygen site will remain deficient ... kinetic energy, a hole's spin hooks up with the random Cu moment to form a ... reach out to each other magnetically to form spin singlet pairs with ...

  17. Spin Dynamics in Highly Spin Polarized Co1-xFexS2

    Science.gov (United States)

    Hoch, Michael J. R.; Kuhns, Philip L.; Moulton, William G.; Reyes, Arneil P.; Lu, Jun; Wang, Lan; Leighton, Chris

    2006-09-01

    Highly spin polarized or half-metallic systems are of considerable current interest because of their potential for spin injection in spintronics applications. The ferromagnet (FM) CoS2 is close to being a half-metal. Recent theoretical and experimental work has shown that the alloys Co1-xFexS2 (0.07 < x < 0.9) are highly spin polarized at low temperatures. The Fe concentration may be used to tune the spin polarization. Using 59Co FM- NMR we have investigated the spin dynamics in this family of alloys and have obtained information on the evolution of the d-band density of states at the Fermi level with x in the range 0 to 0.3. The results are compared with available theoretical predictions.

  18. Performance evaluation of a piezoactuator-based single-stage valve system subjected to high temperature

    Science.gov (United States)

    Jeon, Juncheol; Han, Chulhee; Chung, Jye Ung; Choi, Seung-Bok

    2015-01-01

    In this paper, a novel single-stage valve system activated by a piezostack actuator is proposed and experimentally evaluated at both room temperature (20 °C) and high temperature (100 °C) conditions. A hinge-lever displacement amplifier is adopted in the valve system to magnify the displacement generated from the piezostack actuator. After explaining the operating principle of the proposed piezostack-driven single-stage valve system, the geometric dimensions and mechanical properties of the valve components are discussed in details. An experimental apparatus is then manufactured to evaluate the performances of the valve system such as flow rate. The experimental apparatus consists of a heat chamber, which can regulate the temperature of the valve system and oil, pneumatic-hydraulic cylinders, a hydraulic circuit, a pneumatic circuit, electronic devices, an interface card, and a high voltage amplifier. The pneumatic-hydraulic cylinder transforms the pneumatic pressure into hydraulic pressure. The performances of the valve system regarding spool response, pressure drop, and flow rate are evaluated and presented. In addition, the performance of the valve system under high temperature condition is compared with that under room temperature condition. The experimental results are plotted in both frequency and time domains.

  19. Performance evaluation of a piezoactuator-based single-stage valve system subjected to high temperature

    International Nuclear Information System (INIS)

    Jeon, Juncheol; Han, Chulhee; Ung Chung, Jye; Choi, Seung-Bok

    2015-01-01

    In this paper, a novel single-stage valve system activated by a piezostack actuator is proposed and experimentally evaluated at both room temperature (20 °C) and high temperature (100 °C) conditions. A hinge-lever displacement amplifier is adopted in the valve system to magnify the displacement generated from the piezostack actuator. After explaining the operating principle of the proposed piezostack-driven single-stage valve system, the geometric dimensions and mechanical properties of the valve components are discussed in details. An experimental apparatus is then manufactured to evaluate the performances of the valve system such as flow rate. The experimental apparatus consists of a heat chamber, which can regulate the temperature of the valve system and oil, pneumatic-hydraulic cylinders, a hydraulic circuit, a pneumatic circuit, electronic devices, an interface card, and a high voltage amplifier. The pneumatic-hydraulic cylinder transforms the pneumatic pressure into hydraulic pressure. The performances of the valve system regarding spool response, pressure drop, and flow rate are evaluated and presented. In addition, the performance of the valve system under high temperature condition is compared with that under room temperature condition. The experimental results are plotted in both frequency and time domains. (paper)

  20. Dynamic behavior of prosthetic aortic tissue valves as viewed by high-speed cinematography.

    Science.gov (United States)

    Rainer, W G; Christopher, R A; Sadler, T R; Hilgenberg, A D

    1979-09-01

    Using a valve testing apparatus of our own design and with a high-speed (600 to 800 frames per second) 16 mm movie camera, films were made of Hancock porcine, Carpentier-Edwards porcine, and Ionescu-Shiley bovine pericardial valves mounted in the aortic position and cycled under physiological conditions at 72 to 100 beats per minute. Fresh and explanted valves were observed using saline or 36.5% glycerol as the pumping solution. When fresh valves were studied using saline solution as the pumpint fluid, the Hancock and Carpentier-Edwards porcine valves showed high-frequency leaflet vibration, which increased in frequency with higher cycling rates. Abnormal leaflet motion was decreased when glycerol was used as the blood analogue. The Ionescu-Shiley bovine pericardial valve did not show abnormal leaflet motion under these conditions. Conclusions drawn from tissue valve testing studies that use excessively high pulsing rates and pressures (accelerated testing) and saline or water as pumping solutions cannot be transposed to predict the fate of tissue valves in a clinical setting.

  1. Effect of nano-oxide layers on giant magnetoresistance in pseudo-spin-valves using Co2FeAl electrodes

    International Nuclear Information System (INIS)

    Zhang, D.L.; Xu, X.G.; Wu, Y.; Miao, J.; Jiang, Y.

    2011-01-01

    We studied the pseudo-spin-valves (PSVs) with a structure of Ta/Co 2 FeAl/NOL 1 /Co 2 FeAl/Cu/Co 2 FeAl/NOL 2 /Ta, where NOL represents the nano-oxide layer. Compared with the normal Co 2 FeAl (CFA) PSV with a structure of Ta/Co 2 FeAl/Cu/Co 2 FeAl/Ta, which shows only a current-in-plane (CIP) giant magnetoresistance (GMR) of 0.03%, the CFA PSV with NOLs shows a large CIP-GMR of 5.84%. The enhanced GMR by the NOLs inserted in the CFA PSV is due to the large specular reflection caused by [(CoO)(Fe 2 O 3 )(Al 2 O 3 )] in NOL 1 and [(Fe 2 O 3 )(Al 2 O 3 )(Ta 2 O 5 )] in NOL 2 . Another reason is that the roughness of the interface between Ta and CFA is improved by the oxidation procedure. - Research highlights: → Nano-oxide layers are applied in the pseudo-spin-valves with the Heusler alloy. → The CIP-GMR of pseudo-spin-valves is improved from 0.03% to 5.84%. → The GMR ratio is decided by the position of nano-oxide layers.

  2. High Reliability Cryogenic Piezoelectric Valve Actuator, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Piezoelectric actuators constructed with the "smart material" PZT offer many potential advantages for use in NASA cryo-valve missions relative to conventional...

  3. Study on high reliability safety valve for railway vehicle

    Science.gov (United States)

    Zhang, Xuan; Chen, Ruikun; Zhang, Shixi; Xu, BuDu

    2017-09-01

    Now, the realization of most of the functions of the railway vehicles rely on compressed air, so the demand for compressed air is growing higher and higher. This safety valve is a protection device for pressure limitation and pressure relief in an air supply system of railway vehicles. I am going to introduce the structure, operating principle, research and development process of the safety valve designed by our company in this document.

  4. High-spin states in sd-shell nuclei

    International Nuclear Information System (INIS)

    Poel, C.J. van der.

    1982-01-01

    A systematic picture of the structure of high-spin states in the mass range A = 29 - 41 is developed on the basis of experimental results for the nuclei 34 Cl, 38 K and 39 K. It is shown that for 34 Cl the difficulties induced by the relatively low cross section can be overcome. Combination of the data obtained from a γ-γ coincidence experiment with the 24 Mg + 12 C reaction, using the LACSS, and from threshold measurements in the 31 P + α reaction, establishes an unambiguous level scheme. By means of accurate angular-distribution measurements unambiguous spin and parity assignments are made to the high-spin levels. From the results a rather simple shell-model picture for the structure of the high-spin states evolves. Several authors have published experimental work on high-spin states in 39 K, with seriously conflicting conclusions, however, for the spin-parity assignments. The powerful coincidence set-up with the LACSS enables a discrimination between the conflicting results from the previous studies. In this way, unambiguous, model-independent, spin-parity assignments to the high-spin levels are established. Highly selective experimental methods are used to identify the high-spin states of 38 K. It is shown that with a pulsed beam in the reaction 24 Mg + 16 O advantage can be taken of the presence of a long-lived high-spin isomeric level in this nucleus. The gamma-decay of the isomer is extensively studied. With the pulsed beam, also some states above the isomer could be located. The subsequent use of two Compton-suppression spectrometers in a γ-γ coincidence experiment reveals a number of high-spin levels at higher excitation energies. (Auth.)

  5. Significant manipulation of output performance of a bridge-structured spin valve magnetoresistance sensor via an electric field

    Science.gov (United States)

    Zhang, Yue; Yan, Baiqian; Ou-Yang, Jun; Wang, Xianghao; Zhu, Benpeng; Chen, Shi; Yang, Xiaofei

    2016-01-01

    Through principles of spin-valve giant magnetoresistance (SV-GMR) effect and its application in magnetic sensors, we have investigated electric-field control of the output performance of a bridge-structured Co/Cu/NiFe/IrMn SV-GMR sensor on a PZN-PT piezoelectric substrate using the micro-magnetic simulation. We centered on the influence of the variation of uniaxial magnetic anisotropy constant (K) of Co on the output of the bridge, and K was manipulated via the stress of Co, which is generated from the strain of a piezoelectric substrate under an electric field. The results indicate that when K varies between 2 × 104 J/m3 and 10 × 104 J/m3, the output performance can be significantly manipulated: The linear range alters from between -330 Oe and 330 Oe to between -650 Oe and 650 Oe, and the sensitivity is tuned by almost 7 times, making it possible to measure magnetic fields with very different ranges. According to the converse piezoelectric effect, we have found that this variation of K can be realized by applying an electric field with the magnitude of about 2-20 kV/cm on a PZN-PT piezoelectric substrate, which is realistic in application. This result means that electric-control of SV-GMR effect has potential application in developing SV-GMR sensors with improved performance.

  6. Development of high pressure-high vacuum-high conductance piston valve for gas-filled radiation detectors

    International Nuclear Information System (INIS)

    Prasad, D N; Ayyappan, R; Kamble, L P; Singh, J P; Muralikrishna, L V; Alex, M; Balagi, V; Mukhopadhyay, P K

    2008-01-01

    Gas-filled radiation detectors need gas filling at pressures that range from few cms of mercury to as high as 25kg/cm 2 at room temperature. Before gas-filling these detectors require evacuation to a vacuum of the order of ∼1 x 10 -5 mbar. For these operations of evacuation and gas filling a system consisting of a vacuum pump with a high vacuum gauge, gas cylinder with a pressure gauge and a valve is used. The valve has to meet the three requirements of compatibility with high-pressure and high vacuum and high conductance. A piston valve suitable for the evacuation and gas filling of radiation detectors has been designed and fabricated to meet the above requirements. The stainless steel body (80mmx160mm overall dimensions) valve with a piston arrangement has a 1/2 inch inlet/outlet opening, neoprene/viton O-ring at piston face and diameter for sealing and a knob for opening and closing the valve. The piston movement mechanism is designed to have minimum wear of sealing O-rings. The valve has been hydrostatic pressure tested up to 75bars and has Helium leak rate of less than 9.6x10 -9 m bar ltr/sec in vacuum mode and 2x10 -7 mbar ltr/sec in pressure mode. As compared to a commercial diaphragm valve, which needed 3 hours to evacuate a 7 litre chamber to 2.5x10 -5 mbar, the new valve achieved vacuum 7.4x10 -6 mbar in the same time under the same conditions

  7. A spin-valve-like magnetoresistance of an antiferromagnet-based tunnel junction

    Czech Academy of Sciences Publication Activity Database

    Park, B.G.; Wunderlich, Joerg; Martí, X.; Holý, V.; Kurosaki, Y.; Yamada, M.; Yamamoto, H.; Nishide, A.; Hayakawa, J.; Takahashi, H.; Shick, Alexander; Jungwirth, Tomáš

    2011-01-01

    Roč. 10, č. 5 (2011), s. 347-351 ISSN 1476-1122 R&D Projects: GA AV ČR KAN400100652; GA MŠk LC510; GA MŠk(CZ) 7E08087 EU Projects: European Commission(XE) 268066 - 0MSPIN; European Commission(XE) 214499 - NAMASTE; European Commission(XE) 215368 - SemiSpinNet Grant - others:AV ČR(CZ) AP0801 Program:Akademická prémie - Praemium Academiae Institutional research plan: CEZ:AV0Z10100521; CEZ:AV0Z10100520 Keywords : spintronics * antiferromagnets Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 32.841, year: 2011

  8. CFD simulation on flow induced vibrations in high pressure control and emergency stop turbine valve

    International Nuclear Information System (INIS)

    Lindqvist, H.

    2011-01-01

    During the refuelling outage at Unit 2 of Forsmark NPP in 2009, the high pressure turbine valves were replaced. Three month after recommissioning, an oil pipe connected to one of the actuators was broken. Measurements showed high-frequency vibration levels. The pipe break was suspected to be an effect of highly increased vibrations caused by the new valve. In order to establish the origin of the vibrations, investigations by means of CFD-simulations were made. The simulations showed that the increased vibrations most likely stems from the open cavity that the valves centre consists of. (author)

  9. Element-specific ferromagnetic resonance in epitaxial Heusler spin valve systems

    Energy Technology Data Exchange (ETDEWEB)

    Klaer, P; Jorge, E Arbelo; Jourdan, M; Elmers, H J [Institut fuer Physik, Johannes Gutenberg-Universitaet Mainz, D-55128 Mainz (Germany); Hoffmann, F; Woltersdorf, G; Back, C H, E-mail: elmers@uni-mainz.de [Institut fuer Experimentelle und Angewandte Physik, Universitaet Regensburg, D-93040 Regensburg (Germany)

    2011-10-26

    Time-resolved x-ray magnetic circular dichroism was used to investigate epitaxial MgO(100)/Co{sub 2}Cr{sub 0.6}Fe{sub 0.4}Al and MgO(100)/Co{sub 2}Cr{sub 0.6}Fe{sub 0.4}Al/Cr/CoFe films. The precessional motion of the individual sublattice magnetization, excited by continuous microwave excitation in the range 2-10 GHz, was detected by tuning the x-ray photon energy to the L{sub 3} absorption edges of Cr, Fe and Co. The relative phase angle of the sublattice magnetization's response is smaller than the detection limit of 2{sup 0}. A weakly antiferromagnetically coupled CoFe layer causes an increase in the ferromagnetic resonance linewidth consisting of a constant offset and a component linearly increasing with frequency that we partly attribute to non-local damping due to spin pumping.

  10. Spin valve-like magnetic tunnel diode exhibiting giant positive junction magnetoresistance at low temperature in Co2MnSi/SiO2/p-Si heterostructure

    Science.gov (United States)

    Maji, Nilay; Kar, Uddipta; Nath, T. K.

    2018-02-01

    The rectifying magnetic tunnel diode has been fabricated by growing Co2MnSi (CMS) Heusler alloy film carefully on a properly cleaned p-Si (100) substrate with the help of electron beam physical vapor deposition technique and its structural, electrical and magnetic properties have been experimentally investigated in details. The electronic- and magneto-transport properties at various isothermal conditions have been studied in the temperature regime of 78-300 K. The current-voltage ( I- V) characteristics of the junction show an excellent rectifying magnetic tunnel diode-like behavior throughout that temperature regime. The current ( I) across the junction has been found to decrease with the application of a magnetic field parallel to the plane of the CMS film clearly indicating positive junction magnetoresistance (JMR) of the heterostructure. When forward dc bias is applied to the heterostructure, the I- V characteristics are highly influenced on turning on the field B = 0.5 T at 78 K, and the forward current reduces abruptly (99.2% current reduction at 3 V) which is nearly equal to the order of the magnitude of the current observed in the reverse bias. Hence, our Co2MnSi/SiO2/p-Si heterostructure can perform in off ( I off)/on ( I on) states with the application of non-zero/zero magnetic field like a spin valve at low temperature (78 K).

  11. High Risk Aortic Valve Replacement - The Challenges of Multiple Treatment Strategies with an Evolving Technology.

    Science.gov (United States)

    Booth, K; Beattie, R; McBride, M; Manoharan, G; Spence, M; Jones, J M

    2016-01-01

    Deciding on the optimal treatment strategy for high risk aortic valve replacement is challenging. Transcatheter Aortic Valve implantation (TAVI) has been available in our centre as an alternative treatment modality for patients since 2008. We present our early experience of TAVI and SAVR (surgical Aortic Valve Replacement) in high risk patients who required SAVR because TAVI could not be performed. The database for Surgical aortic valve and Transcatheter aortic valve replacement referrals was interrogated to identify relevant patients. Survival to hospital discharge was 95.5% in the forty five patients who had SAVR when TAVI was deemed technically unsuitable. One year survival was 86%. Defining who is appropriate for TAVI or high risk SAVR is challenging and multidisciplinary team discussion has never been more prudent in this field of evolving technology with ever decreasing risks of surgery. The introduction of TAVI at our institution has seen a rise in our surgical caseload by approximately by 25%. Overall, the option of aortic valve intervention is being offered to more patients in general which is a substantial benefit in the treatment of aortic valve disease.

  12. Significant manipulation of output performance of a bridge-structured spin valve magnetoresistance sensor via an electric field

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yue; Yan, Baiqian; Ou-Yang, Jun; Zhu, Benpeng; Chen, Shi; Yang, Xiaofei, E-mail: hust-yangxiaofei@163.com [School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan 430074 (China); Wang, Xianghao [School of Information Engineering, Wuhan University of Technology, Wuhan 430070 (China)

    2016-01-28

    Through principles of spin-valve giant magnetoresistance (SV-GMR) effect and its application in magnetic sensors, we have investigated electric-field control of the output performance of a bridge-structured Co/Cu/NiFe/IrMn SV-GMR sensor on a PZN-PT piezoelectric substrate using the micro-magnetic simulation. We centered on the influence of the variation of uniaxial magnetic anisotropy constant (K) of Co on the output of the bridge, and K was manipulated via the stress of Co, which is generated from the strain of a piezoelectric substrate under an electric field. The results indicate that when K varies between 2 × 10{sup 4 }J/m{sup 3} and 10 × 10{sup 4 }J/m{sup 3}, the output performance can be significantly manipulated: The linear range alters from between −330 Oe and 330 Oe to between −650 Oe and 650 Oe, and the sensitivity is tuned by almost 7 times, making it possible to measure magnetic fields with very different ranges. According to the converse piezoelectric effect, we have found that this variation of K can be realized by applying an electric field with the magnitude of about 2–20 kV/cm on a PZN-PT piezoelectric substrate, which is realistic in application. This result means that electric-control of SV-GMR effect has potential application in developing SV-GMR sensors with improved performance.

  13. Significant manipulation of output performance of a bridge-structured spin valve magnetoresistance sensor via an electric field

    International Nuclear Information System (INIS)

    Zhang, Yue; Yan, Baiqian; Ou-Yang, Jun; Zhu, Benpeng; Chen, Shi; Yang, Xiaofei; Wang, Xianghao

    2016-01-01

    Through principles of spin-valve giant magnetoresistance (SV-GMR) effect and its application in magnetic sensors, we have investigated electric-field control of the output performance of a bridge-structured Co/Cu/NiFe/IrMn SV-GMR sensor on a PZN-PT piezoelectric substrate using the micro-magnetic simulation. We centered on the influence of the variation of uniaxial magnetic anisotropy constant (K) of Co on the output of the bridge, and K was manipulated via the stress of Co, which is generated from the strain of a piezoelectric substrate under an electric field. The results indicate that when K varies between 2 × 10 4  J/m 3 and 10 × 10 4  J/m 3 , the output performance can be significantly manipulated: The linear range alters from between −330 Oe and 330 Oe to between −650 Oe and 650 Oe, and the sensitivity is tuned by almost 7 times, making it possible to measure magnetic fields with very different ranges. According to the converse piezoelectric effect, we have found that this variation of K can be realized by applying an electric field with the magnitude of about 2–20 kV/cm on a PZN-PT piezoelectric substrate, which is realistic in application. This result means that electric-control of SV-GMR effect has potential application in developing SV-GMR sensors with improved performance

  14. High spin rotational bands in 65 Zn

    Indian Academy of Sciences (India)

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

  15. High spin states in 68Zn

    International Nuclear Information System (INIS)

    Bruandet, J.-F.; Berthet, B.; Morand, C.; Gironi, A.; Longequeue, J.-P.; Tsan Ung Chan.

    1976-01-01

    Yrast levels of 68 Zn have been investigated via measurements of excitation functions and angular distributions of single γ-rays and of γ-γ coincidences. Following the 65 Cu(α,pγ) 68 Zn reaction with α particle energies between 12-21MeV. Spin up to J=8 were assigned to observed states [fr

  16. High-spin states in 66Zn

    International Nuclear Information System (INIS)

    Bruandet, J.F.; Agard, M.; Giorni, A.; Longequeue, J.P.; Morand, C.; Tsan Ung Chan.

    1975-01-01

    The structure of 66 Zn has been investigated by studying the yield functions, angular distributions and coincidence relationships of the γ-rays emitted during bombardment of an enriched 64 Ni foil by α particles of medium energy 27MeV. Spins up to 10 h were assigned to observed states [fr

  17. High spin rotational bands in Zn

    Indian Academy of Sciences (India)

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

  18. Structure of Se at high spin

    Indian Academy of Sciences (India)

    the proton-rich mass-80 nuclei shows considerable variation in going from one nucleus to ... shell gaps at N, Z = 34, 36 and 38 at large deformation. ... systematic increase of the B(E2) values for spins up to I = 14-h has been observed [2] in. 72.

  19. Analysis of Valve Requirements for High-Efficiency Digital Displacement Fluid Power Motors

    DEFF Research Database (Denmark)

    Rømer, Daniel; Johansen, Per; Pedersen, Henrik C.

    2013-01-01

    Digital displacement fluid power motors have been shown to enable high-efficiency operation in a wide operation range, including the part load range where conventional fluid power motors suffers from poor efficiencies. The use of these digital displacement motors set new requirements for the valve...... transition time and flow-pressure coefficient are normalized, leading to a presentation of the general efficiency map of the digital displacement motor. Finally the performance of existing commercial valves with respect to digital motors is commented....

  20. On the testing fast response NPP's valves of large nominal bores and high parameters

    International Nuclear Information System (INIS)

    Majorov, A.P.; Ostretsov, I.N.

    1990-01-01

    Investigation technique for valves of large norminal bores and high parameters which is based on application of simulation effect for operation and accident loadings during movement of valve lock at bench tests with medium flow rate by 100-1000 times less than during operation is given. Loading simulation technique is provided using simulator of lock loading. Investigation results are essential to make decision concerning advisability of serial production of fittings without full-scale test conducting

  1. High spin states in 143Sm

    International Nuclear Information System (INIS)

    Raut, R.; Ganguly, S.; Kshetri, R.; Mukherjee, G.; Mukherjee, A.; Banerjee, P.; Saha Sarkar, M.; Bhattacharya, S.; Goswami, A.; Bhattacharjee, T.; Basu, S.K.; Mukhopadhyaya, S.; Krishichayan; Chakraborty, A.; Gangopadhyay, G.

    2004-01-01

    Large amount of experimental data has been obtained in the recent past on several Nd (Z=60) and Pm (Z=61) isotopes near N=82 shell closure which exhibits an irregular yrast sequence, typical of a non-spherical shape at low spins. The nucleus 143 Sm (Z=62) with a single neutron hole in the N=82 closed shell was investigated as a part of this proposed study

  2. 'Static' octupole deformation at high spin

    International Nuclear Information System (INIS)

    Nazarewicz, W.

    1985-01-01

    Rotational bands characterized by spin states of alternating parity p=(-1) I connected by enhanced E1 transitions have recently been observed in several nuclei from the Ra-Th region. They can be interpreted by means of a reflection asymmetric mean field theory. The interplay between octupole deformation and rotation is briefly discussed. For nuclei with ground state octupole deformation a transition to a reflection symmetric shape is expected around I=22. (orig.)

  3. DEAP actuator and its high voltage driver for heating valve application

    DEFF Research Database (Denmark)

    Huang, Lina; Nørmølle, L. F.; Sarban, R.

    2014-01-01

    Due to the advantages of DEAP (Dielectric Electro Active Polymer) material, such as light weight, noise free operation, high energy and power density and fast response speed, it can be applied in a variety of applications to replace the conventional transducers or actuators. This paper introduces...... DEAP actuator to the heating valve system and conducts a case study to discuss the feasible solution in designing DEAP actuator and its driver for heating valve application. First of all, the heating valves under study are briefly introduced. Then the design and the development for DEAP actuator...... is illustrated in detail, and followed by the detailed investigation of the HV driver for DEAP actuator. In order to verify the implementation, the experimental measurements are carried out for DEAP actuator, its HV driver as well as the entire heating valve system....

  4. Giant magnetoresistance effect in CoZr/Cu/Co spin-valve films (abstract)

    Energy Technology Data Exchange (ETDEWEB)

    Ben-Youssef, J. [CNRS-LMIMS, 92195 Meudon-Bellevue (France)]|[LPM Universite Mohammed V, Rabat (Morocco); Koshkina, O.; Le Gall, H. [CNRS-LMIMS, 92195 Meudon-Bellevue (France); Harfaoui, M.E. [LPMC Universite Ibn Tofail Kenitra (Morocco); Bouziane, K. [CNRS-LMIMS, 92195 Meudon-Bellevue (France); Yamani, M.E. [LPM Universite Mohammed V, Rabat (Morocco); Desvignes, J.M. [CNRS-LMIMS, 92195 Meudon-Bellevue (France)

    1997-04-01

    A high sensitivity of giant magnetoresistance (GMR) has been observed recently from soft magnetic layers such as NiFe, NiFeCo, and FeCoB. Amorphous CoZr alloys present ultrasoft properties compared to NiFe. GMR has been investigated for amorphous CoZr/Cu/Co thin films grown by rf diode sputtering using a target consisting of a Co disk partially covered with a Zr foil. The influence of the argon pressure on Cu layer deposition, Cu thickness, and Zr content on magnetic and transport properties was analyzed. The highest value of transverse GMR obtained along the easy axis is 3.6{percent} and the MR curve was saturated in a magnetic field of 100 Oe at room temperature. GMR shows scaling behavior with the sample composition. Very high sensitivity, around 1{endash}2{percent}/Oe was observed in a CoZr (3 nm)/Cu (3 nm)/Co (2 nm) sandwich. This study shows a large dependence of GMR on Cu thickness and the maximum of magnetoresistance strongly depending on the Ar pressure which modifies the interface roughness. The Zr content also influences the magnetotransport properties ({Delta}R/R and {Delta}R/R{Delta}H). The difference in coercivity between soft magnetic CoZr and hard magnetic Co layers induces antiferromagnetic alignment. Therefore a high MR ratio and field sensitivity are achieved by improving the magnetic properties of the CoZr layer.{copyright} {ital 1997 American Institute of Physics.}

  5. High spin states in 62Cu

    International Nuclear Information System (INIS)

    Tsan Ung Chan; Agard, M.; Bruandet, J.F.; Giorni, A.; Glasser, F.; Longequeue, J.P.; Morand, C.

    1977-06-01

    The 62 Cu nucleus has been studied via the reactions 60 Ni(α,pnγ), 63 Cu(p,pnγ), 52 Cr( 14 N,2p2nγ) using different in beam γ-spectroscopy techniques. The intensity of the principal γ-lines observed in different reactions leading to the 62 Cu has been compared. A brief discussion is made in terms of the independent particle model. A level scheme including levels with spin up to 9 + is proposed [fr

  6. Observational signature of high spin at the Event Horizon Telescope

    Science.gov (United States)

    Gralla, Samuel E.; Lupsasca, Alexandru; Strominger, Andrew

    2018-04-01

    We analytically compute the observational appearance of an isotropically emitting point source on a circular, equatorial orbit near the horizon of a rapidly spinning black hole. The primary image moves on a vertical line segment, in contrast to the primarily horizontal motion of the spinless case. Secondary images, also on the vertical line, display a rich caustic structure. If detected, this unique signature could serve as a `smoking gun' for a high spin black hole in nature.

  7. Nuclear structure at high and very high spin theoretical description

    International Nuclear Information System (INIS)

    Szymanski, Z.

    1983-11-01

    When the existence of nuclear shell structure is ignored and nuclear motion is assumed to be classical we may expect that the nuclear rotation resembles that of a liquid drop. Energy of the nucleus can be thus considered as a sum of three terms: surface energy, Coulomb energy and rotational energy. Nuclear moment of inertia is assumed to be that of a rigid-body. The results of a calculation of the energy surfaces in rotating nuclei by Cohen, Plasil and Swiatecki are discussed. Cranking procedure is analysed as a tool to investigate nucleonic orbits in a rotating nuclear potential. Some predictions concerning the possible onset of a superdeformed phase are given. The structure of nuclear rotation is examined in the presence of the short-range pairing forces that generate the superfluid correlations in the nucleus. Examples of the Bengtsson-Frauendorf plots (quasiparticle energies versus angular velocity of rotation) are given and discussed. The backbending phenomenon is analysed in terms of band crossing. The dependence of the crossing frequency on the pairing-force strength is discussed. Possibilities of the role of new components in the two-body force (quadrupole-pairing) are considered. Possibilities of the phase transition from superfluid to normal states in the nucleus are analysed. The role of the second (dynamic) moment of inertia I(2) in this analysis is discussed. In spherical weekly deformed nuclei (mostly oblate) angular momentum is aligned parallel to the nuclear symmetry axis. Rotation is of non collective origin in this case. Examples of the analysis of nuclear spectra in this case (exhibiting also the isomeric states called yrast (traps)) are given. Possible forms of the collective excitations superimposed on top of the high-spin states are discussed. In particular, the giant resonance excitations formed on top of the high-spin states are considered and their properties discussed

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

    Science.gov (United States)

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

    2005-09-01

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

  9. Steps toward an all-electric spin valve using side-gated quantum point contacts with lateral spin-orbit coupling

    Science.gov (United States)

    Bhandari, Nikhil; Dutta, Maitreya; Charles, James; Newrock, Richard S.; Cahay, Marc; Herbert, Stephen T.

    2013-03-01

    Spin-based electronics or ‘spintronics’ has been a topic of interest for over two decades. Electronic devices based on the manipulation of the electron spin are believed to offer the possibility of very small, non-volatile and ultrafast devices with very low power consumption. Since the proposal of a spin-field-effect transistor (SpinFET) by Datta and Das in 1990, many attempts have been made to achieve spin injection, detection and manipulation in semiconductor materials either by incorporating ferromagnetic materials into device architectures or by using external magnetic fields. This approach has significant design complexities, partly due to the influence of stray magnetic fields on device operation. In addition, magnetic electrodes can have magneto-resistance and spurious Hall voltages that can complicate device performance. To date, there has been no successful report of a working Datta-Das SpinFET. Over the last few years we have investigated an all-electric means of manipulating spins, one that only relies on electric fields and voltages and not on ferromagnetic materials or external magnetic fields. We believe we have found a pathway toward this goal, using in-plane side-gated quantum point contacts (QPCs) that rely on lateral spin-orbit coupling to create spin polarization. In this paper we discuss several aspects of our work, beginning with our finding what we believe is nearly complete spin-polarization in InAs QPCs by purely electrical means, our theoretical work to understand the basic mechanisms leading to that situation (asymmetric lateral confinement, lateral spin-orbit coupling and a strong e-e interaction), and our recent work extending the effort to GaAs and to dual QPC systems where one QPC acts as a polarizer and the other as an analyzer. Keynote talk at the 6th International Workshop on Advanced Materials Science and Nanotechnology, 30 October-2 November 2012, Ha Long, Vietnam.

  10. Performance Evaluation of a High Bandwidth Liquid Fuel Modulation Valve for Active Combustion Control

    Science.gov (United States)

    Saus, Joseph R.; DeLaat, John C.; Chang, Clarence T.; Vrnak, Daniel R.

    2012-01-01

    At the NASA Glenn Research Center, a characterization rig was designed and constructed for the purpose of evaluating high bandwidth liquid fuel modulation devices to determine their suitability for active combustion control research. Incorporated into the rig s design are features that approximate conditions similar to those that would be encountered by a candidate device if it were installed on an actual combustion research rig. The characterized dynamic performance measures obtained through testing in the rig are planned to be accurate indicators of expected performance in an actual combustion testing environment. To evaluate how well the characterization rig predicts fuel modulator dynamic performance, characterization rig data was compared with performance data for a fuel modulator candidate when the candidate was in operation during combustion testing. Specifically, the nominal and off-nominal performance data for a magnetostrictive-actuated proportional fuel modulation valve is described. Valve performance data were collected with the characterization rig configured to emulate two different combustion rig fuel feed systems. Fuel mass flows and pressures, fuel feed line lengths, and fuel injector orifice size was approximated in the characterization rig. Valve performance data were also collected with the valve modulating the fuel into the two combustor rigs. Comparison of the predicted and actual valve performance data show that when the valve is operated near its design condition the characterization rig can appropriately predict the installed performance of the valve. Improvements to the characterization rig and accompanying modeling activities are underway to more accurately predict performance, especially for the devices under development to modulate fuel into the much smaller fuel injectors anticipated in future lean-burning low-emissions aircraft engine combustors.

  11. SLAC workshop on high energy electroproduction and spin physics

    International Nuclear Information System (INIS)

    1992-01-01

    These Proceedings contain copies of the transparencies presented at the Workshop on High Energy Electroproduction and Spin Physics held at SLAC on February 5--8, 1992. The purpose of this Workshop was to bring people together to discuss the possibilities for new experiments using the SLAC high intensity electron and photon beams and the facilities of End Station A

  12. El strength function at high spin and excitation energy

    International Nuclear Information System (INIS)

    Barrette, J.

    1983-04-01

    Recently giant dipole resonance-like concentration of the dipole strength function in nuclei was observed at both high excitation energies and high spins. This observation raises the possibility of obtaining new information on the shape of rapidly rotating heated nuclei. Recent experimental results on this subject are reviewed

  13. High spin states in 162Lu

    International Nuclear Information System (INIS)

    Gupta, S.L.; Pancholi, S.C.; Juneja, P.; Mehta, D.; Kumar, A.; Bhowmik, R.K.; Muralithar, S.; Rodrigues, G.; Singh, R.P.

    1997-01-01

    An experimental investigation of the odd-odd 162 Lu nucleus, following the 148 Sm( 19 F,5n) reaction at beam energy E lab =112MeV, has been performed through in-beam gamma-ray spectroscopy. It revealed three signature-split bands. The yrast band based on πh 11/2 circle-times νi 13/2 configuration exhibits anomalous signature splitting (the unfavored signature Routhian lying lower than the favored one) whose magnitude Δe ' ∼25keV, is considerably reduced in contrast to sizable normal signature splitting Δe ' ∼125 and 60 keV observed in the yrast πh 11/2 bands of the neighboring odd-A 161,163 Lu nuclei, respectively. The signature inversion in this band occurs at spin ∼20ℎ (frequency=0.37MeV). The second signature-split band, observed above the band crossing associated with the alignment of a pair of i 13/2 quasineutrons, is a band based on the four-quasiparticle [πh 11/2 [523]7/2 - times νh 9/2 [521]3/2 - times(νi 13/2 ) 2 ], i.e., EABA p (B p ), configuration. The third signature-split band is also likely to be a four-quasiparticle band with configuration similar to the second band but involving F quasineutron, i.e., FABA p (B p ). The experimental results are discussed in comparison with the existing data in the neighboring nuclei and in the framework of the cranking shell model. copyright 1997 The American Physical Society

  14. Backbending in high spin states of 80Kr

    International Nuclear Information System (INIS)

    Kaushik, M.; Saxena, G.

    2014-01-01

    The study of high-spin states in Kr isotopes near A = 80 region has attracted a considerable interest in recent years. A variety of shapes, shape coexistence as well as backbending phenomenon have been studied in the many of Kr isotopes. In the case of 80 Kr, the high spin structure has been studied by Doring et al. rather extensively and has provided considerable insight into the structure of f-p-g shell nuclei and the competition between single-particle and collective degrees of freedom. Backbending phenomenon is reported in 80 Kr at ω = 0.5 MeV

  15. Optimization of a pressure control valve for high power automatic transmission considering stability

    Science.gov (United States)

    Jian, Hongchao; Wei, Wei; Li, Hongcai; Yan, Qingdong

    2018-02-01

    The pilot-operated electrohydraulic clutch-actuator system is widely utilized by high power automatic transmission because of the demand of large flowrate and the excellent pressure regulating capability. However, a self-excited vibration induced by the inherent non-linear characteristics of valve spool motion coupled with the fluid dynamics can be generated during the working state of hydraulic systems due to inappropriate system parameters, which causes sustaining instability in the system and leads to unexpected performance deterioration and hardware damage. To ensure a stable and fast response performance of the clutch actuator system, an optimal design method for the pressure control valve considering stability is proposed in this paper. A non-linear dynamic model of the clutch actuator system is established based on the motion of the valve spool and coupling fluid dynamics in the system. The stability boundary in the parameter space is obtained by numerical stability analysis. Sensitivity of the stability boundary and output pressure response time corresponding to the valve parameters are identified using design of experiment (DOE) approach. The pressure control valve is optimized using particle swarm optimization (PSO) algorithm with the stability boundary as constraint. The simulation and experimental results reveal that the optimization method proposed in this paper helps in improving the response characteristics while ensuring the stability of the clutch actuator system during the entire gear shift process.

  16. Theory of high-resolution tunneling spin transport on a magnetic skyrmion

    OpenAIRE

    Palotás, Krisztián; Rózsa, Levente; Szunyogh, László

    2018-01-01

    Tunneling spin transport characteristics of a magnetic skyrmion are described theoretically in magnetic scanning tunneling microscopy (STM). The spin-polarized charge current in STM (SP-STM) and tunneling spin transport vector quantities, the longitudinal spin current and the spin transfer torque are calculated in high spatial resolution within the same theoretical framework. A connection between the conventional charge current SP-STM image contrasts and the magnitudes of the spin transport v...

  17. Selection and evaluation of an ultra high vacuum gate valve for Isabelle beam line vacuum system

    International Nuclear Information System (INIS)

    Foerster, C.L.; McCafferty, D.

    1980-01-01

    A minimum of eighty-four (84) Ultra High Vacuum Gate Valves will be utilized in ISABELLE to protect proton beam lines from catastrophic vacuum failure and to provide sector isolation for maintenance requirements. The valve to be selected must function at less than 1 x 10 -11 Torr pressure and be bakeable to 300 0 C in its open or closed position. In the open position, the valve must have an RF shield to make the beam line walls appear continuous. Several proposed designs were built and evaluated. The evaluation consisted mainly of leak testing, life tests, thermal cycling, mass spectrometer analysis, and 10 -12 Torr operation. Problems with initial design and fabrication were resolved. Special requirements for design and construction were developed. This paper describes the tests on two final prototypes which appear to be the best candidates for ISABELLE operation

  18. Highly Efficient Spin-Current Operation in a Cu Nano-Ring

    Science.gov (United States)

    Murphy, Benedict A.; Vick, Andrew J.; Samiepour, Marjan; Hirohata, Atsufumi

    2016-11-01

    An all-metal lateral spin-valve structure has been fabricated with a medial Copper nano-ring to split the diffusive spin-current path. We have demonstrated significant modulation of the non-local signal by the application of a magnetic field gradient across the nano-ring, which is up to 30% more efficient than the conventional Hanle configuration at room temperature. This was achieved by passing a dc current through a current-carrying bar to provide a locally induced Ampère field. We have shown that in this manner a lateral spin-valve gains an additional functionality in the form of three-terminal gate operation for future spintronic logic.

  19. High spin states in the f-p shell

    International Nuclear Information System (INIS)

    Delaunay, J.

    1975-01-01

    The high spin states (HSS) in Fe, Co, Ni (Z=26,27,28) isotopes exhibit features characteristics of soft or transition nuclei, 56 Fe being as well deformed prolate nucleus and the Ni isotopes often throught of as spherical. The methodology used to identify these HSS is the so called DCO (directional correlation of oriented nuclei) or ratio method which, by combining the angular distribution data plus one point of a triple γ-γ correlation in an asymmetric geometry, gives result that is found equivalent to a complete angular correlation to assign spin and mixing ratios. Some results collected with this methodology are presented [fr

  20. Spins in the vortices of a high-temperature superconductor

    DEFF Research Database (Denmark)

    Lake, B.; Aeppli, G.; Clausen, K.N.

    2001-01-01

    Neutron scattering is used to characterize the magnetism of the vortices for the optimally doped high-temperature superconductor La2-xSrxCuO4 (x = 0.163) in an applied magnetic field. As temperature is reduced, Low-frequency spin fluctuations first disappear with the loss of vortex mobility......, but then reappear. We find that the vortex state can be regarded as an inhomogeneous mixture of a superconducting spin fluid and a material containing a nearly ordered antiferromagnet. These experiments show that as for many other properties of cuprate superconductors, the important underlying microscopic forces...

  1. Gross shell structure at high spin in heavy nuclei

    International Nuclear Information System (INIS)

    Deleplanque, Marie-Agnes; Frauendorf, Stefan; Pashkevich, Vitaly V.; Chu, S.Y.; Unzhakova, Anja

    2003-01-01

    Experimental nuclear moments of inertia at high spins along the yrast line have been determined systematically and found to differ from the rigid-body values. The difference is attributed to shell effect and these have been calculated microscopically. The data and quantal calculations are interpreted by means of the semiclassical Periodic Orbit Theory. From this new perspective, features in the moments of inertia as a function of neutron number and spin, as well as their relation to the shell energies can be understood. Gross shell effects persist up to the highest angular momenta observed

  2. Level Structure of 103Ag at high spins

    OpenAIRE

    Ray, S.; Pattabiraman, N. S.; Krishichayan; Chakraborty, A.; Mukhopadhyay, S.; Ghugre, S. S.; Chintalapudi, S. N.; Sinha, A. K.; Garg, U.; Zhu, S.; Kharraja, B.; Almehed, D.

    2007-01-01

    High spin states in $^{103}$Ag were investigated with the Gammasphere array, using the $^{72}$Ge($^{35}$Cl,$2p2n$)$^{103}$Ag reaction at an incident beam energy of 135 MeV. A $\\Delta J$=1 sequence with predominantly magnetic transitions and two nearly-degenerate $\\Delta J=1$ doublet bands have been observed. The dipole band shows a decreasing trend in the $B(M1)$ strength as function of spin, a well established feature of magnetic bands. The nearly-degenerate band structures satisfy the three...

  3. Significance of high energy spin effects in constituent pictures

    International Nuclear Information System (INIS)

    Chen, C.K.

    1977-01-01

    The spin information about high energy hadronic reactions is important for further understanding of the nature and the behavior of hadronic constituents. The usefulness of the information is discussed in the cases of dilepton production from hadronic collisions, large P/sub T/ inclusive and elastic scatterings, and small angle elastic scattering and quantum number exchanged reactions

  4. High-spin structure of neutron-rich Dy isotopes

    Indian Academy of Sciences (India)

    Neutron-rich Dy isotopes; high-spin states; g-factors; cranked HFB theory. ... for 164Dy marking a clear separation in the behaviour as a function of neutron ... cipal x-axis as the cranking axis) in this mass region we have planned to make a sys-.

  5. Experimental evidence for shape changes at high spin

    International Nuclear Information System (INIS)

    Twin, P.J.

    1985-01-01

    Recent experimental evidence obtained with TESSA for shape changes at high spin is presented. Continuum γ-ray spectroscopy data indicates the co-existence of both prolate and oblate shapes in N = 90 nuclei and lifetime data in 152 Dy shows that the super deformed decays are very enhanced. (orig.)

  6. 3 QP plus rotor model and high spin states

    International Nuclear Information System (INIS)

    Mathur, Tripti

    1995-01-01

    Nuclear models are approximate methods to describe certain properties of a large number of nuclei. In this paper details of 3 QP (three quasi particle) plus rotor model and high spin state are discussed. The band head energies for the 3 QP rotational bands for 157 Ho and 159 Tm are also given. 5 refs., 8 figs

  7. Moments of inertia in 162Yb at very high spins

    International Nuclear Information System (INIS)

    Simon, R.S.; Banaschik, M.V.; Colombani, P.; Soroka, D.P.; Stephens, F.S.; Diamond, R.M.

    1976-01-01

    Two methods have been used to obtain values of the effective moment of inertia of very-high-spin (20h-bar--50h-bar) states populated in heavy-ion compound-nucleus reactions. The 162 Yb nucleus studied has effective moments of inertia smaller than, but approaching, the rigid-body estimate

  8. Lifetimes of high-spin states in {sup 162}Yb

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter, M.P.; Janssens, R.V.F.; Henry, R.G. [and others

    1995-08-01

    A measurement on lifetimes of high-spin states in the yrast and near-yrast rotational bands in {sup 162}Yb was carried out at ATLAS in order to determine the evolution of collectivity as a function of angular momentum using the {sup 126}Te({sup 40}Ar,4n){sup 162}Yb reaction at 170 MeV. Previous lifetime measurements in the {sup 164,166,168}Yb isotopes showed a dramatic decrease in the transition quadrupole moment Q{sub t} with increasing spin. It was suggested that this decrease in Q{sub t} is brought about by the rotationally-induced deoccupation of high-j configurations, mainly i{sub 13/2} neutrons. If this interpretation is correct, the heavier isotopes should have a larger decrease in Q{sub t} than the lighter mass nuclides due to the position of the Fermi surface in the i{sub 13/2} subshell. Indeed, {sup 160}Yb does not show a clear decrease in Q{sub t} at high spin. No high spin lifetime information exists for {sup 162}Yb, thus this experiment fills the gap of measured Q{sub t}`s in the light Yb series. The data is currently being analyzed.

  9. Observation of high spin levels in Cs from Ba decay

    Indian Academy of Sciences (India)

    physics pp. 1157–1162. Observation of high spin levels in. 131. Cs from. 131. Ba decay. M SAINATH, DWARAKA RANI RAO*, K VENKATARAMANIAH and P C SOOD. Department of Physics, Sri Sathya Sai Institute of Higher Learning, Prasanthinilayam 515 134, India. £Permanent address: Department of Physics, ...

  10. Andreev spectrum with high spin-orbit interactions: Revealing spin splitting and topologically protected crossings

    Science.gov (United States)

    Murani, A.; Chepelianskii, A.; Guéron, S.; Bouchiat, H.

    2017-10-01

    In order to point out experimentally accessible signatures of spin-orbit interaction, we investigate numerically the Andreev spectrum of a multichannel mesoscopic quantum wire (N) with high spin-orbit interaction coupled to superconducting electrodes (S), contrasting topological and nontopological behaviors. In the nontopological case (square lattice with Rashba interactions), we find that the Kramers degeneracy of Andreev levels is lifted by a phase difference between the S reservoirs except at multiples of π , when the normal quantum wires can host several conduction channels. The level crossings at these points invariant by time-reversal symmetry are not lifted by disorder. Whereas the dc Josephson current is insensitive to these level crossings, the high-frequency admittance (susceptibility) at finite temperature reveals these level crossings and the lifting of their degeneracy at π by a small Zeeman field. We have also investigated the hexagonal lattice with intrinsic spin-orbit interaction in the range of parameters where it is a two-dimensional topological insulator with one-dimensional helical edges protected against disorder. Nontopological superconducting contacts can induce topological superconductivity in this system characterized by zero-energy level crossing of Andreev levels. Both Josephson current and finite-frequency admittance carry then very specific signatures at low temperature of this disorder-protected Andreev level crossing at π and zero energy.

  11. Toroidal high-spin isomers in the nucleus 304120

    Science.gov (United States)

    Staszczak, A.; Wong, Cheuk-Yin; Kosior, A.

    2017-05-01

    Background: Strongly deformed oblate superheavy nuclei form an intriguing region where the toroidal nuclear structures may bifurcate from the oblate spheroidal shape. The bifurcation may be facilitated when the nucleus is endowed with a large angular moment about the symmetry axis with I =Iz . The toroidal high-K isomeric states at their local energy minima can be theoretically predicted using the cranked self-consistent Skyrme-Hartree-Fock method. Purpose: We use the cranked Skyrme-Hartree-Fock method to predict the properties of the toroidal high-spin isomers in the superheavy nucleus 120304184. Method: Our method consists of three steps: First, we use the deformation-constrained Skyrme-Hartree-Fock-Bogoliubov approach to search for the nuclear density distributions with toroidal shapes. Next, using these toroidal distributions as starting configurations, we apply an additional cranking constraint of a large angular momentum I =Iz about the symmetry z axis and search for the energy minima of the system as a function of the deformation. In the last step, if a local energy minimum with I =Iz is found, we perform at this point the cranked symmetry- and deformation-unconstrained Skyrme-Hartree-Fock calculations to locate a stable toroidal high-spin isomeric state in free convergence. Results: We have theoretically located two toroidal high-spin isomeric states of 120304184 with an angular momentum I =Iz=81 ℏ (proton 2p-2h, neutron 4p-4h excitation) and I =Iz=208 ℏ (proton 5p-5h, neutron 8p-8h) at the quadrupole moment deformations Q20=-297.7 b and Q20=-300.8 b with energies 79.2 and 101.6 MeV above the spherical ground state, respectively. The nuclear density distributions of the toroidal high-spin isomers 120304184(Iz=81 ℏ and 208 ℏ ) have the maximum density close to the nuclear matter density, 0.16 fm-3, and a torus major to minor radius aspect ratio R /d =3.25 . Conclusions: We demonstrate that aligned angular momenta of Iz=81 ℏ and 208 ℏ arising from

  12. DEVELOPMENT OF NEW VALVE STEELS FOR APPLICATION IN HIGH PERFORMANCE ENGINES

    Directory of Open Access Journals (Sweden)

    Alexandre Bellegard Farina

    2013-12-01

    Full Text Available UNS N07751 and UNS N07080 alloys are commonly applied for automotive valves production for high performance internal combustion engines. These alloys present high hot resistance to mechanical strength, oxidation, corrosion, creep and microstructural stability. However, these alloys presents low wear resistance and high cost due to the high nickel contents. In this work it is presented the development of two new Ni-based alloys for application in high performance automotive valve as an alternative to the alloys UNS N07751 and UNS N07080. The new developed alloys are based on a high nickel-chromium austenitic matrix with dispersion of γ’ and γ’’ phases and containing different NbC contents. Due to the nickel content reduction in the developed alloys in comparison with these actually used alloys, the new alloys present an economical advantage for substitution of UNS N07751 and UNS N0780 alloys.

  13. Novel room-temperature spin-valve-like magnetoresistance in magnetically coupled nano-column Fe3O4/Ni heterostructure.

    Science.gov (United States)

    Xiao, Wen; Song, Wendong; Herng, Tun Seng; Qin, Qing; Yang, Yong; Zheng, Ming; Hong, Xiaoliang; Feng, Yuan Ping; Ding, Jun

    2016-08-25

    Herein, we design a room-temperature spin-valve-like magnetoresistance in a nano-column Fe3O4/Ni heterostructure without using a non-magnetic spacer or pinning layer. An Fe3O4 nano-column film is self-assembled on a Ni underlayer by the thermal decomposition method. The wet-chemical self-assembly is facile, economical and scalable. The magnetoresistance (MR) response of the Ni underlayer in the heterostructure under positive and negative out-of-plane magnetic fields differ by ∼0.25 at room temperature and ∼0.43 at 100 K. We attribute the spin-valve-like magnetoresistance to the unidirectional magnetic anisotropy of the Ni underlayer when being magnetically coupled by the Fe3O4 nano-column film. The out-of-plane negative-field magnetization is higher than the positive-field magnetization, affirming the unidirectional magnetic anisotropy of the Fe3O4/Ni heterostructure. Temperature-dependent magnetic and resistivity studies illustrate a close correlation between the magnetization transition of Fe3O4 and resistivity transition of Ni and prove a magnetic coupling between the Fe3O4 and Ni. First-principles calculations reveal that the Fe3O4/Ni model under a negative magnetic field is energetically more stable than that under a positive magnetic field. Furthermore, partial density of states (PDOS) analysis demonstrates the unidirectional magnetic anisotropy of the Ni 3d orbital. This is induced by the strong ferromagnetic coupling between Fe3O4 and Ni via oxygen-mediated Fe 3d-O 2p-Ni 3d hybridizations.

  14. Control performances of a piezoactuator direct drive valve system at high temperatures with thermal insulation

    Science.gov (United States)

    Han, Yung-Min; Han, Chulhee; Kim, Wan Ho; Seong, Ho Yong; Choi, Seung-Bok

    2016-09-01

    This technical note presents control performances of a piezoactuator direct drive valve (PDDV) operated at high temperature environment. After briefly discussing operating principle and mechanical dimensions of the proposed PDDV, an appropriate size of the PDDV is manufactured. As a first step, the temperature effect on the valve performance is experimentally investigated by measuring the spool displacement at various temperatures. Subsequently, the PDDV is thermally insulated using aerogel and installed in a large-size heat chamber in which the pneumatic-hydraulic cylinders and sensors are equipped. A proportional-integral-derivative feedback controller is then designed and implemented to control the spool displacement of the valve system. In this work, the spool displacement is chosen as a control variable since it is directly related to the flow rate of the valve system. Three different sinusoidal displacements with different frequencies of 1, 10 and 50 Hz are used as reference spool displacement and tracking controls are undertaken up to 150 °C. It is shown that the proposed PDDV with the thermal insulation can provide favorable control responses without significant tracking errors at high temperatures.

  15. First example of a high-level correlated calculation of the indirect spin-spin coupling constants involving tellurium

    DEFF Research Database (Denmark)

    Rusakov, Yury Yu; Krivdin, Leonid B.; Østerstrøm, Freja From

    2013-01-01

    This paper documents a very first example of a high-level correlated calculation of spin-spin coupling constants involving tellurium taking into account relativistic effects, vibrational corrections and solvent effects for the medium sized organotellurium molecules. The 125Te-1H spin-spin coupling...... constants of tellurophene and divinyl telluride were calculated at the SOPPA and DFT levels in a good agreement with experiment. A new full-electron basis set av3z-J for tellurium derived from the "relativistic" Dyall's basis set, dyall.av3z, and specifically optimized for the correlated calculations...... of spin-spin coupling constants involving tellurium, was developed. The SOPPA methods show much better performance as compared to 15 those of DFT, if relativistic effects calculated within the ZORA scheme are taken into account. Vibrational and solvent corrections are next to negligible, while...

  16. Spin polarization in high density quark matter

    DEFF Research Database (Denmark)

    Bohr, Henrik; Panda, Prafulla K.; Providênci, Constanca

    2013-01-01

    We investigate the occurrence of a ferromagnetic phase transition in high density hadronic matter (e.g., in the interior of a neutron star). This could be induced by a four-fermion interaction analogous to the one which is responsible for chiral symmetry breaking in the Nambu-Jona-Lasinio model, ...... the so-called 2 flavor super-conducting phase to the ferromagnetic phase arises. The color-flavor-locked phase may be completely hidden by the FP....

  17. High precision pulsar timing and spin frequency second derivatives

    Science.gov (United States)

    Liu, X. J.; Bassa, C. G.; Stappers, B. W.

    2018-05-01

    We investigate the impact of intrinsic, kinematic and gravitational effects on high precision pulsar timing. We present an analytical derivation and a numerical computation of the impact of these effects on the first and second derivative of the pulsar spin frequency. In addition, in the presence of white noise, we derive an expression to determine the expected measurement uncertainty of a second derivative of the spin frequency for a given timing precision, observing cadence and timing baseline and find that it strongly depends on the latter (∝t-7/2). We show that for pulsars with significant proper motion, the spin frequency second derivative is dominated by a term dependent on the radial velocity of the pulsar. Considering the data sets from three Pulsar Timing Arrays, we find that for PSR J0437-4715 a detectable spin frequency second derivative will be present if the absolute value of the radial velocity exceeds 33 km s-1. Similarly, at the current timing precision and cadence, continued timing observations of PSR J1909-3744 for about another eleven years, will allow the measurement of its frequency second derivative and determine the radial velocity with an accuracy better than 14 km s-1. With the ever increasing timing precision and observing baselines, the impact of the, largely unknown, radial velocities of pulsars on high precision pulsar timing can not be neglected.

  18. Theory of high-resolution tunneling spin transport on a magnetic skyrmion

    Science.gov (United States)

    Palotás, Krisztián; Rózsa, Levente; Szunyogh, László

    2018-05-01

    Tunneling spin transport characteristics of a magnetic skyrmion are described theoretically in magnetic scanning tunneling microscopy (STM). The spin-polarized charge current in STM (SP-STM) and tunneling spin transport vector quantities, the longitudinal spin current and the spin transfer torque, are calculated in high spatial resolution within the same theoretical framework. A connection between the conventional charge current SP-STM image contrasts and the magnitudes of the spin transport vectors is demonstrated that enables the estimation of tunneling spin transport properties based on experimentally measured SP-STM images. A considerable tunability of the spin transport vectors by the involved spin polarizations is also highlighted. These possibilities and the combined theory of tunneling charge and vector spin transport pave the way for gaining deep insight into electric-current-induced tunneling spin transport properties in SP-STM and to the related dynamics of complex magnetic textures at surfaces.

  19. Very high-spin states in nuclei

    International Nuclear Information System (INIS)

    Diamond, R.M.

    1977-03-01

    The continuum γ-ray spectrum following emission in a (HI,xn) reaction consists of a high-energy tail, the statistical cascade, and a lower-energy bump, the yrast cascade, which contains most of the intensity and consists mostly of stretched E2 transitions. Thus, a good approximation to the average angular momentum carried by the γ-ray is 2Nsub(γ). Under favourable conditions, effective moments of inertia can be deduced for states up to the top of the γ-ray cascade. The maximum angular momentum in the cascades is probably limited by α-emission for nuclei with A 150. (Author)

  20. Modeling the collective excitations in a full Heusler Co2 FeAl0.5 Si0.5 (CFAS) spin valve magnetic nanopillar in the electromagnetic field

    International Nuclear Information System (INIS)

    David, Cherine; Arumugam, Brinda; Rajamani, Amuda; Natarajan, Kanimozhi

    2014-01-01

    This paper describes the physics of collective excitations that are caused by spin-transfer torques in CFAS magnetic multilayer. When the magnetizations of the pinned and free layers are not collinear with each other, the spin-polarized currents transfer angular momentum to the magnetizations near the interfaces, giving rise to spin-transfer torques. The currents in magnetic multilayer are spin polarised and can carry enough angular momentum. When an electron spin carried by the current interacts with a magnetic layer, the exchange interaction leads to torque between the spin and the magnetization vector of the free layer. This is Spin Transfer Torque (STT) and it excites the magnetization when it is large enough. The Spin Transfer Torque induced collective excitations for the CFAS spin valve pillar have been extensively studied in this paper. - Highlights: • We have modeled LLGS equation for CFAS multilayer array. • The dynamics of collective excitation induced by STT is investigated. • The interactions exhibit solitonic behaviour at both limiting modes of polarization. • The spin components of the solitons are graphically represented

  1. Island of high-spin isomers near N = 82

    International Nuclear Information System (INIS)

    Pedersen, J.; Back, B.B.; Bernthal, F.M.; Bjornholm, S.; Borggreen, J.; Christensen, O.; Folkmann, F.; Herskind, B.; Khoo, T.L.; Neiman, M.; Puehlhofer, F.; Sletten, G.

    1977-01-01

    Experiments aimed at testing for the existence of yrast traps are reported. A search for delayed γ radiation of lifetimes longer than approx. 10 ns and of high multiplicity has been performed by producing more than 100 compound nuclei between Ba and Pb in bombardments with 40 Ar, 50 Ti, and 65 Cu projectiles. An island of high-spin isomers is found to exist in the region 64 or approx. = 71 and N < or approx. = 82

  2. High temperature resistant nanofiber by bubbfil-spinning

    Directory of Open Access Journals (Sweden)

    Li Ya

    2015-01-01

    Full Text Available Heat-resisting nanofibers have many potential applications in various industries, and the bubbfil spinning is the best candidate for mass-production of such materials. Polyether sulfone/zirconia solution with a bi-solvent system is used in the experiment. Experimental result reveals that polyether sulfone/zirconia nanofibers have higher resistance to high temperature than pure polyether sulfone fibers, and can be used as high-temperature-resistant filtration materials.

  3. Very high-spin states in nuclei

    International Nuclear Information System (INIS)

    Diamond, R.M.

    1977-01-01

    The continuum γ-ray spectrum following neutron emission in a (HI,xn) reaction consists of a high-energy tail, the statistical cascade, and a lower-energy bump, the yrast cascade, which contains most of the intensity and consists mostly of stretched E2 transitions. Thus, a good approximation to the average angular momentum carried by the γ-rays is 2N/sub γ/-bar. Under favourable conditions, effective moments of inertia can be deduced for states up to the top of the γ-ray cascade. The maximum angular momentum in the cascades is probably limited by α-emission for nuclei with A 150. 17 figures

  4. High and highest spin states in nuclei

    International Nuclear Information System (INIS)

    Ploszajczak, M.

    1977-06-01

    A study of the following phenomena in rotating nuclei is presented, namely: 1) the destruction of the pair-correlation between the protons and the neutrons as well as decoupling and orientation of the particles along the rotation axis; 2) the formation of a nucleus with axial symmetry rotating around the symmetry axis, caused by the strong centrifugal and Coriolis forces; 3) the shell effects at low angular momentum, which led in some Pb, Hg and Pt isotopes to the formation of a prolate nucleus, rotating around the symmetry axis; 4) the formation of longliving states at very high angular momenta ('Yrast-traps'). At low angular momenta the nucleus is described by the Cranking-Hartree-Fock-Bogolyubov theory (CHFB) with the pair-(P), quadrupole-(QQ) and hexade coupole force (HH) as residual interaction. (orig.) [de

  5. Spin-polarons and high-Tc superconductivity

    International Nuclear Information System (INIS)

    Wood, R.F.

    1994-03-01

    The spin-polaron concept is introduced in analogy to ionic and electronic polarons and the assumptions underlying the author's approach to spin-polaron mediated high-T c superconductivity are discussed. Elementary considerations about the spin-polaron formation energy are reviewed and the possible origin of the pairing mechanism illustrated schematically. The electronic structure of the CuO 2 planes is treated from the standpoint of antiferromagnetic band calculations that lead directly to the picture of holes predominantly on the oxygen sublattice in a Mott-Hubbard/charge transfer insulator. Assuming the holes to be described in a Bloch representation but with the effective mass renormalized by spin-polaron formation, equations for the superconducting gap, Δ, and transition temperature, T c , are developed and the symmetry of Δ discussed. After further simplifications, T c is calculated as a function of the carrier concentration, x. It is shown that the calculated behavior of T c (x) follows the experimental results closely and leads to a natural explanation of the effects of under- and over-doping. The paper concludes with a few remarks about the evidence for the carriers being fermions (polarons) or bosons (bipolarons)

  6. 91Mo and 89Nb high-spin states

    International Nuclear Information System (INIS)

    Baktybaev, K.; Kojlyk, N.; Ramankulov, K.E.

    2003-01-01

    In the work the shell-model calculation for 91 Mo and 89 Nb nuclei high-spin states with several valente nucleons is worked out. The nucleons have been arranged in the {2p 1/2 1g 9 / 2 } configurations above the 88 Sr twice magic frame. Using of formalism of generalized quasi-spin with H=H 0 +H pp +H nn +H pn Hamiltonian in which H pp , H nn , H pn the residual nucleon interactions have being written through generalized quasi-spin operators. The obtained scheme well reproduces experimental data for examined nuclei up to 31/2 + , 33/2 - levels with seniority ν=3.5. Similarity of the spectroscopic structures of the nucleus levels with different protons and neutrons numbers above inert frame shows independence of nucleon-nucleon interactions from isotope spins of particles. There are analogous comparison of some negative yrast bands parity levels. The theory well transmits intensity values for electromagnet transitions between states. Besides the observed nuclei's properties does not give any indication on presence of valent nucleons collective motion in the both nuclei

  7. Study on microstructure and high temperature wear resistance of laser cladded nuclear valve clack

    International Nuclear Information System (INIS)

    Zhang Chunliang; Chen Zichen

    2002-01-01

    Laser cladding of Co-base alloy on the nuclear valve-sealing surface are performed with a 5 kW CO 2 transverse flowing laser. The microstructure and the high temperature impact-slide wear resistance of the laser cladded coating and the plasma cladded coating are studied. The results show that the microstructure, the dilution rate and the high temperature impact-slide wear resistance of the laser cladded coating have obvious advantages over the spurt cladding processing

  8. Design, fabrication and characterization of an arrayable all-polymer microfluidic valve employing highly magnetic rare-earth composite polymer

    International Nuclear Information System (INIS)

    Rahbar, Mona; Gray, Bonnie L; Shannon, Lesley

    2016-01-01

    We present a new magnetically actuated microfluidic valve that employs a highly magnetic composite polymer (M-CP) containing rare-earth hard-magnetic powder for its actuating element and for its valve seat. The M-CP offers much higher magnetization compared to the soft-magnetic, ferrite-based composite polymers typically used in microfluidic applications. Each valve consists of a permanently magnetized M-CP flap and valve seat mounted on a microfluidic channel system fabricated in poly(dimethylsiloxane) (PDMS). Each valve is actuated under a relatively small external magnetic field of 80 mT provided by a small permanent magnet mounted on a miniature linear actuator. The performance of the valve with different flap thicknesses is characterized. In addition, the effect of the magnetic valve seat on the valve’s performance is also characterized. It is experimentally shown that a valve with a 2.3 mm flap thickness, actuated under an 80 mT magnetic field, is capable of completely blocking liquid flow at a flow rate of 1 ml min −1 for pressures up to 9.65 kPa in microfluidic channels 200 μ m wide and 200 μ m deep. The valve can also be fabricated into an array for flow switching between multiple microfluidic channels under continuous flow conditions. The performance of arrays of valves for flow routing is demonstrated for flow rates up to 5 ml min −1 with larger microfluidic channels of up to 1 mm wide and 500 μ m deep. The design of the valves is compatible with other commonly used polymeric microfluidic components, as well as other components that use the same novel permanently magnetic composite polymer, such as our previously reported cilia-based mixing devices. (paper)

  9. Nuclear spin relaxation in a spin-1/2 antiferromagnetic Heisenberg chain at high fields

    International Nuclear Information System (INIS)

    Lyo, S.K.

    1981-01-01

    The proton spin relaxation rate is calculated in the one-dimensional spin-1/2 Heisenberg antiferromagnet α-bis (N-methylsalicylaldiminato)-copper (II), α-CuNSal by using a fermion representation for magnons above the critical field where the magnon spectrum develops a gap. The one-magnon process which is dominant below the critical field is shown to be absent in the presence of a gap in contrast to a previous theory. Instead, we find that the three-magnon rate is large enough to explain the data at low fields. The two-magnon off-resonance damping which enters the expression for the three-magnon rate is calculated by solving the two-magnon scattering exactly, leading to a much smaller value of the rate than that predicted by the Born approximation. Also, in an unsuccessful attempt to resolve the discrepancy between the recently calculated two-magnon rate (dominant at high fields) and the data of α-CuNSal reported by Azevedo et al., we carry out the vertex correction for the spin-density correlation function by summing the RPA series as well as the exchange ladders for the polarization part. We find that, although the exchange enhancement is significantly large, it is nearly canceled out by the RPA correction, and the net effect of the vertex correction is small. This result agrees with the recent data of the similar spin-1/2 antiferromagnetic Heisenberg chain system CuSO 4 x5H 2 O reported by Groen et al. On the other hand, it disagrees with a recent calculation of the two-magnon rate based on a boson representation of spins. To resolve this discrepancy we examine the effect of the boson self-energy correction on the two-magnon rate. The boson spectral shift is found to be quite large in the region where the cited two-boson rate deviates from the two-fermion rate. As a result the two-boson rate is significantly reduced, leading to reasonable agreement with the two-fermion rate

  10. Fluid dynamics of giant resonances on high spin states

    International Nuclear Information System (INIS)

    Di Nardo, M.; Di Toro, M.; Giansiracusa, G.; Lombardo, U.; Russo, G.

    1983-01-01

    We describe giant resonances built on high spin states along the yrast line as scaling solutions of a linearized Vlasov equation in a rotating frame obtained from a TDHF theory in phase space. For oblate cranked solutions we get a shift and a splitting of the isoscalar giant resonances in terms of the angular velocity. Results are shown for 40 Ca and 168 Er. The relative CM strengths are also calculated. (orig.)

  11. Nuclear data for the high-spin community

    Energy Technology Data Exchange (ETDEWEB)

    Firestone, R B [Lawrence Berkeley Lab., CA (United States); Singh, B [McMaster Univ., Hamilton, ON (Canada). Tandem Accelerator Lab.

    1992-08-01

    The Isotopes Project at Berkeley is developing the Evaluated High-Spin Data File, a subset of the Evaluated Nuclear Structure Data File (ENSDF). The following products were under development at the time of the conference: eighth edition of the Table of Isotopes, electronic table of isotopes, data bases, nuclear charts, nuclear wallet cards, nuclear CD-ROM, FAX data services, on-line data services.

  12. High spin states and backbending in the light tungsten isotopes

    International Nuclear Information System (INIS)

    Walker, P.M.; Dracoulis, G.D.; Johnston, A.; Leigh, J.R.; Slocombe, M.G.; Wright, I.F.

    1976-09-01

    High spin states in 172 W, 174 W, 175 W and 176 W have been studied with ( 16 O,xn) reactions. The ground state bands in 174 W and 176 W backbend in contrast to the more regular gsb in the N = 98 nucleus 172 W. This behaviour and the anomalies in the odd nucleus 175 W are discussed in terms of the influence of neutrons on backbending. (author)

  13. STUDY OF THE HIGH-SPIN STRUCTURE OF PM-146

    NARCIS (Netherlands)

    RZACAURBAN, T; DURELL, JL; PHILLIPS, WR; VARLEY, BJ; HESS, CP; PEARSON, CJ; VERMEER, WJ; VIEU, C; DIONISIO, JS; PAUTRAT, M; Urban, W

    1995-01-01

    Excited states in Pm-146 have been investigated through the Xe-136(N-15,5n) and the Nd-146(d,xn) compound-nucleus reactions. A level scheme extending up to 6.9 MeV of excitation energy and (I = 25HBAR) is proposed. Most of the high-spin levels are interpreted in terms of multi-particle-hole states

  14. pp spin correlations at high p/sub T/

    International Nuclear Information System (INIS)

    Auer, I.P.; Colton, E.; Ditzler, W.R.

    1980-01-01

    New data are presented for measurements of the spin correlation in pp reactions with longitudinally polarized beam and target. Data were obtained at 11.75 GeV/c for both elastic scattering and for π + - and π - -production at high p/sub T/ in pp reactions at 11.75 GeV/c. A comparison is made with recent predictions of quark-parton models

  15. High-mobility ultrathin semiconducting films prepared by spin coating.

    Science.gov (United States)

    Mitzi, David B; Kosbar, Laura L; Murray, Conal E; Copel, Matthew; Afzali, Ali

    2004-03-18

    The ability to deposit and tailor reliable semiconducting films (with a particular recent emphasis on ultrathin systems) is indispensable for contemporary solid-state electronics. The search for thin-film semiconductors that provide simultaneously high carrier mobility and convenient solution-based deposition is also an important research direction, with the resulting expectations of new technologies (such as flexible or wearable computers, large-area high-resolution displays and electronic paper) and lower-cost device fabrication. Here we demonstrate a technique for spin coating ultrathin (approximately 50 A), crystalline and continuous metal chalcogenide films, based on the low-temperature decomposition of highly soluble hydrazinium precursors. We fabricate thin-film field-effect transistors (TFTs) based on semiconducting SnS(2-x)Se(x) films, which exhibit n-type transport, large current densities (>10(5) A cm(-2)) and mobilities greater than 10 cm2 V(-1) s(-1)--an order of magnitude higher than previously reported values for spin-coated semiconductors. The spin-coating technique is expected to be applicable to a range of metal chalcogenides, particularly those based on main group metals, as well as for the fabrication of a variety of thin-film-based devices (for example, solar cells, thermoelectrics and memory devices).

  16. High-mobility ultrathin semiconducting films prepared by spin coating

    Science.gov (United States)

    Mitzi, David B.; Kosbar, Laura L.; Murray, Conal E.; Copel, Matthew; Afzali, Ali

    2004-03-01

    The ability to deposit and tailor reliable semiconducting films (with a particular recent emphasis on ultrathin systems) is indispensable for contemporary solid-state electronics. The search for thin-film semiconductors that provide simultaneously high carrier mobility and convenient solution-based deposition is also an important research direction, with the resulting expectations of new technologies (such as flexible or wearable computers, large-area high-resolution displays and electronic paper) and lower-cost device fabrication. Here we demonstrate a technique for spin coating ultrathin (~50Å), crystalline and continuous metal chalcogenide films, based on the low-temperature decomposition of highly soluble hydrazinium precursors. We fabricate thin-film field-effect transistors (TFTs) based on semiconducting SnS2-xSex films, which exhibit n-type transport, large current densities (>105Acm-2) and mobilities greater than 10cm2V-1s-1-an order of magnitude higher than previously reported values for spin-coated semiconductors. The spin-coating technique is expected to be applicable to a range of metal chalcogenides, particularly those based on main group metals, as well as for the fabrication of a variety of thin-film-based devices (for example, solar cells, thermoelectrics and memory devices).

  17. Orientation estimation algorithm applied to high-spin projectiles

    International Nuclear Information System (INIS)

    Long, D F; Lin, J; Zhang, X M; Li, J

    2014-01-01

    High-spin projectiles are low cost military weapons. Accurate orientation information is critical to the performance of the high-spin projectiles control system. However, orientation estimators have not been well translated from flight vehicles since they are too expensive, lack launch robustness, do not fit within the allotted space, or are too application specific. This paper presents an orientation estimation algorithm specific for these projectiles. The orientation estimator uses an integrated filter to combine feedback from a three-axis magnetometer, two single-axis gyros and a GPS receiver. As a new feature of this algorithm, the magnetometer feedback estimates roll angular rate of projectile. The algorithm also incorporates online sensor error parameter estimation performed simultaneously with the projectile attitude estimation. The second part of the paper deals with the verification of the proposed orientation algorithm through numerical simulation and experimental tests. Simulations and experiments demonstrate that the orientation estimator can effectively estimate the attitude of high-spin projectiles. Moreover, online sensor calibration significantly enhances the estimation performance of the algorithm. (paper)

  18. Orientation estimation algorithm applied to high-spin projectiles

    Science.gov (United States)

    Long, D. F.; Lin, J.; Zhang, X. M.; Li, J.

    2014-06-01

    High-spin projectiles are low cost military weapons. Accurate orientation information is critical to the performance of the high-spin projectiles control system. However, orientation estimators have not been well translated from flight vehicles since they are too expensive, lack launch robustness, do not fit within the allotted space, or are too application specific. This paper presents an orientation estimation algorithm specific for these projectiles. The orientation estimator uses an integrated filter to combine feedback from a three-axis magnetometer, two single-axis gyros and a GPS receiver. As a new feature of this algorithm, the magnetometer feedback estimates roll angular rate of projectile. The algorithm also incorporates online sensor error parameter estimation performed simultaneously with the projectile attitude estimation. The second part of the paper deals with the verification of the proposed orientation algorithm through numerical simulation and experimental tests. Simulations and experiments demonstrate that the orientation estimator can effectively estimate the attitude of high-spin projectiles. Moreover, online sensor calibration significantly enhances the estimation performance of the algorithm.

  19. Nuclear high-spin data for A = 174, 176 and 184

    Energy Technology Data Exchange (ETDEWEB)

    Junde, Huo [Jilin Univ. (China). Dept. of Physics

    1996-06-01

    Nuclear high-spin data are important in the frontier areas of nuclear structure physics. The information on A = 174, 176 and 184 mass chains from various reaction experiments together with their adopted high-spin levels and gamma transition properties are presented and discussed. High-spin data for A = 174, 176 and 184 mass chains were evaluated in 1995.

  20. High spin cycles: topping the spin record for a single molecule verging on quantum criticality

    Science.gov (United States)

    Baniodeh, Amer; Magnani, Nicola; Lan, Yanhua; Buth, Gernot; Anson, Christopher E.; Richter, Johannes; Affronte, Marco; Schnack, Jürgen; Powell, Annie K.

    2018-03-01

    The cyclisation of a short chain into a ring provides fascinating scenarios in terms of transforming a finite array of spins into a quasi-infinite structure. If frustration is present, theory predicts interesting quantum critical points, where the ground state and thus low-temperature properties of a material change drastically upon even a small variation of appropriate external parameters. This can be visualised as achieving a very high and pointed summit where the way down has an infinity of possibilities, which by any parameter change will be rapidly chosen, in order to reach the final ground state. Here we report a mixed 3d/4f cyclic coordination cluster that turns out to be very near or even at such a quantum critical point. It has a ground state spin of S = 60, the largest ever observed for a molecule (120 times that of a single electron). [Fe10Gd10(Me-tea)10(Me-teaH)10(NO3)10].20MeCN forms a nano-torus with alternating gadolinium and iron ions with a nearest neighbour Fe-Gd coupling and a frustrating next-nearest neighbour Fe-Fe coupling. Such a spin arrangement corresponds to a cyclic delta or saw-tooth chain, which can exhibit unusual frustration effects. In the present case, the quantum critical point bears a `flatland' of tens of thousands of energetically degenerate states between which transitions are possible at no energy costs with profound caloric consequences. Entropy-wise the energy flatland translates into the pointed summit overlooking the entropy landscape. Going downhill several target states can be reached depending on the applied physical procedure which offers new prospects for addressability.

  1. High Frequency QPOs due to Black Hole Spin

    Science.gov (United States)

    Kazanas, Demos; Fukumura, K.

    2009-01-01

    We present detailed computations of photon orbits emitted by flares at the innermost stable circular orbit (ISCO) of accretion disks around rotating black holes. We show that for sufficiently large spin parameter, i.e. a > 0.94 M, flare a sufficient number of photons arrive at an observer after multiple orbits around the black hole, to produce an "photon echo" of constant lag, i.e. independent of the relative phase between the black hole and the observer, of T approximates 14 M. This constant time delay, then, leads to a power spectrum with a QPO at a frequency nu approximates 1/14M, even for a totally random ensemble of such flares. Observation of such a QPO will provide incontrovertible evidence for the high spin of the black hole and a very accurate, independent, measurement of its mass.

  2. High spin structure in 130,131Ba

    International Nuclear Information System (INIS)

    Kaur, Navneet; Kumar, A.; Singh, Amandeep; Kumar, S.; Kaur, Rajbir; Singh, Varinderjit; Behera, B.R.; Singh, K.P.; Singh, G.; Mukherjee, G.; Sharma, H.P.; Kumar, Suresh; Kumar Raju, M.; Madhusudhan Rao, P.V.; Muralithar, S.; Singh, R.P.; Kumar, Rakesh; Madhvan, N.; Bhowmik, R.K.

    2014-01-01

    High spin states of 130,131 Ba have been investigated via fusion evaporation reactions 122 Sn( 13 C,4n) 131 Ba and 122 Sn( 13 C, 5n) 130 Ba at E beam =65 MeV. The level schemes of 130,131 Ba have been extended by placing several new γ transitions. A few interband transitions connecting two negative-parity bands, which are the experimental fingerprints of signature partners, have been established in 130 Ba. Spin and parity of a side band have been assigned in 131 Ba and this dipole band is proposed to have a three-quasiparticle configuration, νh 11/2 x πh 11/2 x πg 7/2 . The observed band structures and nuclear shape evolution as a function of the angular momentum have been discussed in the light of Total-Routhian-Surface calculations. (orig.)

  3. Fully aligned high-spin states in 86Zr

    International Nuclear Information System (INIS)

    Doring, J.; Hohns, G.D.; Sylvan, G.N.

    1995-01-01

    To study multi-quasiparticle excitations and their interplay with collective degrees of freedom at very high spins, a new in-beam investigation of the even-even 86 Zr has been performed via the 58 Ni( 32 S,4p) reaction at 135 MeV using the early implementation of GAMMASPHERE combined with the 47π charged particle detector system MICROBALL. The yrast positive- and negative-parity sequences have been extended up to 30 + and 27 - levels, respectively. Calculations within the configuration-dependent shell-correction method using a cranked Nilsson potential have shown that the highest spins are built from the six g 9 /2 neutrons and at most four protons excited from the p 1/2 , p 3/2 , f 5/2 subshells to the g 9 /2 subshell at a small deformation. The 30 + and 27 - states are the highest possible fully-aligned states based on holes in the N = 3 shell. Higher spins can be built by promotion of one neutron from the g 9 /2 to the g 7 /2 subshell but with a quite high energy cost

  4. Collectivity of high spin states in {sup 84}Zr

    Energy Technology Data Exchange (ETDEWEB)

    Lister, C.J.; Blumenthal, D.; Crowell, B. [and others

    1995-08-01

    {sup 84}Zr is one of the most extensively studied of the A {approximately} 80 rotors, both from theoretical and experimental approaches. It was predicted to be a good candidate to support superdeformation, and to show interesting spectroscopic properties including saturation of its shell-model space at lower spin. We performed an experiment using Gammasphere in its early implementation phase. The reaction of {sup 29}Si on {sup 58}Ni was used to strongly populate {sup 84}Zr at high spin. Thin and thick targets were used to allow the extraction of transitional matrix elements at very high spin, and to allow a sensitive search for superdeformed states. Data analysis is in progress. The large data set allowed us to extend the previously known bands considerably. Candidates for a staggered M1-band, found previously {sup 86}Zr, were located. To date, no evidence for superdeformed bands was found. Analysis was slowed by the relocation of all the participants in this experiment, but we hope to complete the lifetime analysis this year. This analysis has become especially topical, due to reported measurements of superdeformation in this region.

  5. Causes of death from the randomized CoreValve US Pivotal High-Risk Trial.

    Science.gov (United States)

    Gaudiani, Vincent; Deeb, G Michael; Popma, Jeffrey J; Adams, David H; Gleason, Thomas G; Conte, John V; Zorn, George L; Hermiller, James B; Chetcuti, Stan; Mumtaz, Mubashir; Yakubov, Steven J; Kleiman, Neal S; Huang, Jian; Reardon, Michael J

    2017-06-01

    Explore causes and timing of death from the CoreValve US Pivotal High-Risk Trial. An independent clinical events committee adjudicated causes of death, followed by post hoc hierarchical classification. Baseline characteristics, early outcomes, and causes of death were evaluated for 3 time periods (selected based on threshold of surgical 30-day mortality and on the differences in the continuous hazard between the 2 groups): early (0-30 days), recovery (31-120 days), and late (121-365 days). Differences in the rate of death were evident only during the recovery period (31-120 days), whereas 15 patients undergoing transcatheter aortic valve replacement (TAVR) (4.0%) and 27 surgical aortic valve replacement (SAVR) patients (7.9%) died (P = .025). This mortality difference was largely driven by higher rates of technical failure, surgical complications, and lack of recovery following surgery. From 0 to 30 days, the causes of death were more technical failures in the TAVR group and lack of recovery in the SAVR group. Mortality in the late period (121-365 days) in both arms was most commonly ascribed to other circumstances, comprising death from medical complications from comorbid disease. Mortality at 1 year in the CoreValve US Pivotal High-Risk Trial favored TAVR over SAVR. The major contributor was that more SAVR patients died during the recovery period (31-121 days), likely affected by the overall influence of physical stress associated with surgery. Similar rates of technical failure and complications were observed between the 2 groups. This suggests that early TAVR results can improve with technical refinements and that high-risk surgical patients will benefit from reducing complications. Copyright © 2017 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

  6. Summary of the 9th international symposium on high energy spin-physics

    International Nuclear Information System (INIS)

    Prescott, C.Y.

    1990-11-01

    Summarizing an international conference in high energy spin physics is never an easy task, because of the wide-ranging subjects in physics and technology that are involved. I have chosen to organize the topics of this conference into three broad categories relating to spin; intrinsic spin; composite spin; and spin, the experimental tool. In the first category, I will briefly revisit some historical and recent developments to set a background. In the second category, composite spin, I will discuss the status and developments in several areas, including magnetic moments of baryons, hyperon polarization in high energy high p perpendicular production, transverse polarization and asymmetries from transversely polarized targets in high p perpendicular scattering, spin structure of the proton, and the Bjorken sum rule. In the third category, I will discuss the steady, and at times rapid, progress in spin technology. In this part I include recent progress in high energy facilities, and comment on the highlights of the Workshops

  7. Bioprosthetic Valve Fracture Improves the Hemodynamic Results of Valve-in-Valve Transcatheter Aortic Valve Replacement.

    Science.gov (United States)

    Chhatriwalla, Adnan K; Allen, Keith B; Saxon, John T; Cohen, David J; Aggarwal, Sanjeev; Hart, Anthony J; Baron, Suzanne J; Dvir, Danny; Borkon, A Michael

    2017-07-01

    Valve-in-valve (VIV) transcatheter aortic valve replacement (TAVR) may be less effective in small surgical valves because of patient/prosthesis mismatch. Bioprosthetic valve fracture (BVF) using a high-pressure balloon can be performed to facilitate VIV TAVR. We report data from 20 consecutive clinical cases in which BVF was successfully performed before or after VIV TAVR by inflation of a high-pressure balloon positioned across the valve ring during rapid ventricular pacing. Hemodynamic measurements and calculation of the valve effective orifice area were performed at baseline, immediately after VIV TAVR, and after BVF. BVF was successfully performed in 20 patients undergoing VIV TAVR with balloon-expandable (n=8) or self-expanding (n=12) transcatheter valves in Mitroflow, Carpentier-Edwards Perimount, Magna and Magna Ease, Biocor Epic and Biocor Epic Supra, and Mosaic surgical valves. Successful fracture was noted fluoroscopically when the waist of the balloon released and by a sudden drop in inflation pressure, often accompanied by an audible snap. BVF resulted in a reduction in the mean transvalvular gradient (from 20.5±7.4 to 6.7±3.7 mm Hg, P valve effective orifice area (from 1.0±0.4 to 1.8±0.6 cm 2 , P valves to facilitate VIV TAVR with either balloon-expandable or self-expanding transcatheter valves and results in reduced residual transvalvular gradients and increased valve effective orifice area. © 2017 American Heart Association, Inc.

  8. Design and manufacture of high performance hollow engine valves by Additive Layer Manufacturing

    International Nuclear Information System (INIS)

    Cooper, D.; Thornby, J.; Blundell, N.; Henrys, R.; Williams, M.A.; Gibbons, G.

    2015-01-01

    Highlights: • High performance engine valve has been redesigned and optimised for and using ALM. • FEA was utilised to optimise and select a design for manufacture and testing. • Micro computed tomography was used in design and validation as an NDT technique. • Real world test of components was conducted to evaluate their performance. • Has demonstrated the potential for ALM in a high performance engineering context. - Abstract: Additive Layer Manufacture (ALM) of metallic components provides significant opportunities for the reduction of component weight, in order to realise improvements in vehicle fuel efficiency or performance. This paper examines the potential benefits of ALM with regard to reducing the weight of Internal Combustion Engine inlet or exhaust valves. A case study component is presented, for which an improved ALM design has been created, manufactured and evaluated. Micro-Computed Tomography (μ-CT) scanning was utilised to reverse engineer an original component, and to assess the ALM component’s internal geometry and material integrity. The case study valve was re-designed using Finite Element Analysis (FEA) to select a light weighted design which provides a conservative 9.4 g, (20%) weight saving on the Original Equipment Manufacturer (OEM) component. An engine test of over 175,000 cycles at between 2000 and 9500 rpm was conducted, after which μ-CT scanning confirmed no evidence of internal cracking, failure or significant deformation

  9. Electron spin polarization in high-energy storage rings

    International Nuclear Information System (INIS)

    Mane, S.R.

    1987-01-01

    In a high energy storage ring, a single photon emission has relatively little effect on the orbital motion, but it can produce a relatively large change in the electron spin state. Hence the unperturbed orbital motion can be satisfactorily described using classical mechanics, but the spin must be treated quantum mechanically. The electron motion is therefore treated semi-classically in this thesis. It is explained how to diagonalize the unperturbed Hamiltonian to the leading order in Planck's constant. The effects of perturbations are then included, and the relevant time-scales and ensemble averages are elucidated. The Derbenev-Kondratenko formula for the equilibrium degree of polarization is rederived. Mathematical details of the rederivation are given. Since the original authors used a different formalism, a proof is offered of the equivalence between their method and the one used in this thesis. An algorithm is also presented to evaluate the equilibrium polarization. It has a number of new features, which enable the polarization to be calculated to a higher degree of approximation than has hitherto been possible. This facilitates the calculation of so-called spin resonances, which are points at which the polarization almost vanishes. A computer program has been written to implement the above algorithm, in the approximation of linear orbital dynamics, and sample results are presented

  10. Recent developments in high-spin calculations in atomic nuclei

    International Nuclear Information System (INIS)

    Szymanski, Z.

    1980-01-01

    A brief introduction to the recent achievements in the high-spin domain in nuclear physics is given. Results of the calculations in highly developed rotational bands in deformed nuclei, as well as the calculations in the structure of the yrast isomers are presented. The calculations fail in two aspects: local minima in the yrast line are not confirmed experimentally, the overall slope of the yrast line in 152 Dy is considerably overestimated. The calculations of the yrast line with new Woods-Saxon parameters are now in progress. The parameters are chosen to reproduce the large gap in the levels at proton number Z=64. (M.H.)

  11. Two-proton radioactivity in proton-rich fp shell nuclei at high spin

    Energy Technology Data Exchange (ETDEWEB)

    Aggarwal, Mamta [Nuclear Science Centre, Aruna Asaf Ali Marg, Post Box 10502, New Delhi 110067 (India)

    2006-07-15

    Two-proton radioactivity in extremely proton-rich fp shell nuclei at high spins is investigated in a theoretical framework. Separation energy and entropy fluctuate with spin and hence affect the location of the proton drip line.

  12. Two-proton radioactivity in proton-rich fp shell nuclei at high spin

    International Nuclear Information System (INIS)

    Aggarwal, Mamta

    2006-01-01

    Two-proton radioactivity in extremely proton-rich fp shell nuclei at high spins is investigated in a theoretical framework. Separation energy and entropy fluctuate with spin and hence affect the location of the proton drip line

  13. Exchange bias mechanism in FM/FM/AF spin valve systems in the presence of random unidirectional anisotropy field at the AF interface: The role played by the interface roughness due to randomness

    Science.gov (United States)

    Yüksel, Yusuf

    2018-05-01

    We propose an atomistic model and present Monte Carlo simulation results regarding the influence of FM/AF interface structure on the hysteresis mechanism and exchange bias behavior for a spin valve type FM/FM/AF magnetic junction. We simulate perfectly flat and roughened interface structures both with uncompensated interfacial AF moments. In order to simulate rough interface effect, we introduce the concept of random exchange anisotropy field induced at the interface, and acting on the interface AF spins. Our results yield that different types of the random field distributions of anisotropy field may lead to different behavior of exchange bias.

  14. Spin dynamics in relativistic ionization with highly charged ions in super-strong laser fields

    International Nuclear Information System (INIS)

    Klaiber, Michael; Yakaboylu, Enderalp; Bauke, Heiko; Hatsagortsyan, Karen Z; Müller, Carsten; Paulus, Gerhard G

    2014-01-01

    Spin dynamics and induced spin effects in above-threshold ionization of hydrogenlike highly charged ions in super-strong laser fields are investigated. Spin-resolved ionization rates in the tunnelling regime are calculated by employing two versions of a relativistic Coulomb-corrected strong-field approximation (SFA). An intuitive simpleman model is developed which explains the derived scaling laws for spin flip and spin asymmetry effects. The intuitive model as well as our ab initio numerical simulations support the analytical results for the spin effects obtained in the dressed SFA where the impact of the laser field on the electron spin evolution in the bound state is taken into account. In contrast, the standard SFA is shown to fail in reproducing spin effects in ionization even at a qualitative level. The anticipated spin-effects are expected to be measurable with modern laser techniques combined with an ion storage facility. (paper)

  15. Highly spin-polarized materials and devices for spintronics∗.

    Science.gov (United States)

    Inomata, Koichiro; Ikeda, Naomichi; Tezuka, Nobuki; Goto, Ryogo; Sugimoto, Satoshi; Wojcik, Marek; Jedryka, Eva

    2008-01-01

    The performance of spintronics depends on the spin polarization of the current. In this study half-metallic Co-based full-Heusler alloys and a spin filtering device (SFD) using a ferromagnetic barrier have been investigated as highly spin-polarized current sources. The multilayers were prepared by magnetron sputtering in an ultrahigh vacuum and microfabricated using photolithography and Ar ion etching. We investigated two systems of Co-based full-Heusler alloys, Co 2 Cr 1 - x Fe x Al (CCFA( x )) and Co 2 FeSi 1 - x Al x (CFSA( x )) and revealed the structure and magnetic and transport properties. We demonstrated giant tunnel magnetoresistance (TMR) of up to 220% at room temperature and 390% at 5 K for the magnetic tunnel junctions (MTJs) using Co 2 FeSi 0.5 Al 0.5 (CFSA(0.5)) Heusler alloy electrodes. The 390% TMR corresponds to 0.81 spin polarization for CFSA(0.5) at 5 K. We also investigated the crystalline structure and local structure around Co atoms by x-ray diffraction (XRD) and nuclear magnetic resonance (NMR) analyses, respectively, for CFSA films sputtered on a Cr-buffered MgO (001) substrate followed by post-annealing at various temperatures in an ultrahigh vacuum. The disordered structures in CFSA films were clarified by NMR measurements and the relationship between TMR and the disordered structure was discussed. We clarified that the TMR of the MTJs with CFSA(0.5) electrodes depends on the structure, and is significantly higher for L2 1 than B2 in the crystalline structure. The second part of this paper is devoted to a SFD using a ferromagnetic barrier. The Co ferrite is investigated as a ferromagnetic barrier because of its high Curie temperature and high resistivity. We demonstrate the strong spin filtering effect through an ultrathin insulating ferrimagnetic Co-ferrite barrier at a low temperature. The barrier was prepared by the surface plasma oxidization of a CoFe 2 film deposited on a MgO (001) single crystal substrate, wherein the spinel

  16. Managing high risk glaucoma with the Ahmed valve implant: 20 years of experience.

    Science.gov (United States)

    Rotsos, Tryfon; Tsioga, Anastasia; Andreanos, Konstantinos; Diagourtas, Andreas; Petrou, Petros; Georgalas, Ilias; Papaconstantinou, Dimitrios

    2018-01-01

    To estimate the efficacy and safety of the Ahmed implant in patients with high risk for failure after glaucoma surgery. In 342 eyes of 342 patients with refractory glaucoma, even with application of medical treatment, the Ahmed valve was introduced for intraocular pressure (IOP) control, in the period of the last 20y. The nature of glaucoma was neovascular in 162 eyes, pseudophakic or aphakic in 49 eyes, inflammatory in 29 eyes and non working previous antiglaucomatic surgical interventions in 102 eyes. Follow-up ranged from 18 to 120mo with a mean follow-up of 63.2mo. IOP before the operation decreased from 31.6±10.4 mm Hg to 18.3±5.4 mm Hg (no systemic treatment) at the end of follow up period. When we compared the IOP values before the operation using ANOVA showed statistically significant difference ( P glaucoma, 63.2% in aphakic glaucoma and 73.8% in non working previous antiglaucomatic surgical interventions. Complications due to the implant were: serous choroidal detachment in 14.8%, blockage of the tube in 2.8%, malposition of the tube in 4.9%, suprachoroidal hemorrhage in 2.1%, cataract progression in 39.6% (phakic eyes), shallow anterior chamber in 9.2%, hyphaema in 28.9%, exposure of valve in 2.6%, exposure of tube in 9.3%, hypotony in 4.9% and conjunctival fibrosis in 41.5%. Despite the fact that Ahmed valve implant had suchlike results as other implants concerning the IOP control, complications rate due to hypotony or over filtration in the first days after the intervention are not that frequent as with other valve implants.

  17. Denervation of pulmonary artery during mitral valve surgery in patients with high pulmonary hypertension

    Directory of Open Access Journals (Sweden)

    А. В. Богачев-Прокофьев

    2016-01-01

    Full Text Available Objective. Pulmonary hypertension impairs the mitral valve and often leads to more severe symptoms of heart failure, low exercise tolerance and thus higher rates of morbidity and mortality. The purpose of this study is to evaluate the safety and efficacy of simultaneous radiofrequency ablation of ganglionated plexi of the pulmonary artery in patients with high pulmonary hypertension during mitral valve surgery.Methods. The inclusion criteria were based on patients’ echocardiography/right heart catheterization data. The main criteria were mean pulmonary artery pressure ≥40 mm Hg at rest and a positive reactive test with nitric oxide inhalation. From January 2014 to May 2015, 14 patients underwent radiofrequency denervation of the pulmonary artery in addition to planned mitral valve surgery. Mean patient age was 53.4±7.8 years, with 57.1% of patients being females.Results. Mean cardiopulmonary bypass time was 116±12 minutes, mean cross-clamp time was 95±13 minutes, and mean ablation time amounted to 9.5±3.1 minutes. Pulmonary artery pressure decreased significantly from a mean of 56.5±9.8 mmHg to 32.0±7.3 mmHg immediately after the operation (p<0.001, and to 28.4±5.2 mmHg and 29.7±4.4 mmHg on the first and third days at ICU respectively. Mean ICU stay was 3.1±1.2 days. There were neither early deaths nor specific complications.Conclusions. Simultaneous radiofrequency ablation of pulmonary artery ganglionated plexi when performing mitral valve surgery in patients with pulmonary hypertension is a safe and effective procedure. Further research and long-term follow-up would help to determine whether a decrease in the mean pressure of the pulmonary artery can be interpreted as a clinical advantage.

  18. Low Temperature Electrical Spin Injection from Highly Spin Polarized Co₂CrAl Heusler Alloy into p-Si.

    Science.gov (United States)

    Kar, Uddipta; Panda, J; Nath, T K

    2018-06-01

    The low temperature spin accumulation in p-Si using Co2CrAl/SiO2 tunnel junction has been investigated in detail. The heterojunction has been fabricated using electron beam evaporation (EBE) technique. The 3-terminal contacts in Hanle geometry has been made for spin transport measurements. The electrical transport properties have been investigated at different isothermal conditions in the temperature range of 10-300 K. The current-voltage characteristics of the junction shows excellent rectifying magnetic diode like behaviour in lower temperature range (below 200 K). At higher temperature, the junction shows nonlinear behaviour without rectifying characteristics. We have observed spin accumulation signal in p-Si semiconductor using SiO2/Co2CrAl tunnel junction in the low temperature regime (30-100 K). Hence the highly spin polarized Full Heusler alloys compounds, like Co2CrAl etc., are very attractive and can act as efficient tunnel device for spin injection in the area of spintronics devices in near future. The estimated spin life time is τ = 54 pS and spin diffusion length inside p-Si is LSD = 289 nm at 30 K for this heterostructure.

  19. Swing check valve

    International Nuclear Information System (INIS)

    Eminger, H.E.

    1977-01-01

    A swing check valve which includes a valve body having an inlet and outlet is described. A recess in the valve body designed to hold a seal ring and a check valve disc swingable between open and closed positions. The disc is supported by a high strength wire secured at one end in a support spacer pinned through bearing blocks fixed to the valve body and at its other end in a groove formed on the outer peripheral surface of the disc. The parts are designed and chosen such to provide a lightweight valve disc which is held open by minimum velocity of fluid flowing through the valve which thus reduces oscillations and accompanying wear of bearings supporting the valve operating parts. (Auth.)

  20. Collective properties and shapes of nuclei at very high spins

    International Nuclear Information System (INIS)

    Johnson, N.R.

    1991-01-01

    A topic which has been of major interest to us for some years now involves the evolution of nuclear collectivity at high rotational frequencies and the accompanying changes in the shapes of nuclei in these extreme conditions. We carry out these studies by determining the dynamic electromagnetic multipole moments which are a reflection of the collective aspects of the nuclear wave functions. The most direct way to get these multipole moments is by measurements of excited-state lifetimes which provide the transition matrix elements in a fairly straightforward fashion. Although the primary emphasis of this paper is on the collectivity of the high-spin states in 160 Yb and 164 Yb, it is important to review briefly some work we began about ten years ago lifetime studies of moderately high spins in nuclei near N=90 using the recoil-distance (RD) method. These nuclei are just at the onset of permanent deformation and are known to be very soft with respect to deformation changes. This softness is clearly illustrated in contour diagrams of their potential-energy surfaces. For example, the potential energy surface of 160 Yb reveals that the minimum in the potential occurs around var-epsilon ∼ 0.2 and that it is very shallow in the γ degree of freedom. Because of their γ softness, we have studied several nuclei near N=90 to assess to what extent the polarization effects induced by rotation alignment of high-j quasiparticles affect their collectivity

  1. Spin dynamics in high-TC superconducting cuprates

    International Nuclear Information System (INIS)

    Bourges, Ph.

    2003-07-01

    This work is dedicated to the detailed investigations of the magnetic resonance peak in the superconducting state of cuprates. The existence of such a peak could be the signature of a mechanism linked to magnetism that could explain high critical temperature superconductivity. Inelastic neutron scattering is an adequate tool for the understanding of cuprate properties because it reveals magnetic fluctuations whose behaviour and variety depend strongly on temperature and on the level of doping. The last part of this work is dedicated to the study of spin dynamics in YBa 2 Cu 3 O 6+x system

  2. Modeling, Parameters Identification, and Control of High Pressure Fuel Cell Back-Pressure Valve

    Directory of Open Access Journals (Sweden)

    Fengxiang Chen

    2014-01-01

    Full Text Available The reactant pressure is crucial to the efficiency and lifespan of a high pressure PEMFC engine. This paper analyses a regulated back-pressure valve (BPV for the cathode outlet flow in a high pressure PEMFC engine, which can achieve precisely pressure control. The modeling, parameters identification, and nonlinear controller design of a BPV system are considered. The identified parameters are used in designing active disturbance rejection controller (ADRC. Simulations and extensive experiments are conducted with the xPC Target and show that the proposed controller can not only achieve good dynamic and static performance but also have strong robustness against parameters’ disturbance and external disturbance.

  3. CCF analysis of high redundancy systems safety/relief valve data analysis and reference BWR application

    International Nuclear Information System (INIS)

    Mankamo, T.; Bjoere, S.; Olsson, Lena

    1992-12-01

    Dependent failure analysis and modeling were developed for high redundancy systems. The study included a comprehensive data analysis of safety and relief valves at the Finnish and Swedish BWR plants, resulting in improved understanding of Common Cause Failure mechanisms in these components. The reference application on the Forsmark 1/2 reactor relief system, constituting of twelve safety/relief lines and two regulating relief lines, covered different safety criteria cases of reactor depressurization and overpressure protection function, and failure to re close sequences. For the quantification of dependencies, the Alpha Factor Model, the Binomial Probability Model and the Common Load Model were compared for applicability in high redundancy systems

  4. Structure and magnetoresistive properties of current-perpendicular-to-plane pseudo-spin valves using polycrystalline Co2Fe-based Heusler alloy films

    International Nuclear Information System (INIS)

    Nakatani, T.M.; Du, Ye; Takahashi, Y.K.; Furubayashi, T.; Hono, K.

    2013-01-01

    We report current-perpendicular-to-plane giant magnetoresistance (CPP–GMR) of pseudo-spin valves (PSVs) with polycrystalline Co 2 Fe(Al 0.5 Si 0.5 ) (CFAS) and Co 2 Fe(Ga 0.5 Ge 0.5 ) (CFGG) Heusler alloy films. Strongly [0 1 1] textured polycrystalline Heusler alloy films grew on the Ta/Ru/Ag underlayer. Relatively large CPP–GMR values of ΔRA up to 4 mΩ μm 2 and ΔR/R up to 10% were obtained with 5 nm thick Heusler alloy films and Ag spacer layer by annealing CFAS PSV at 450 °C and CFGG PSV at 350 °C. Transmission electron microscopy revealed a flat and sharp interface between the [0 1 1] textured CFAS layers and the [1 1 1] textured Ag spacer layer. Annealing above an optimal temperature for each PSV led to reductions in MR values as a result of the thickening of the spacer layer induced by the Ag diffusion from the outer Ag layers

  5. Towards sub-200 nm nano-structuring of linear giant magneto-resistive spin valves by a direct focused ion beam milling process

    International Nuclear Information System (INIS)

    Riedmüller, Benjamin; Huber, Felix; Herr, Ulrich

    2014-01-01

    In this work, we present a detailed investigation of a focused ion beam (FIB) assisted nano-structuring process for giant magneto-resistive (GMR) spin valve sensors. We have performed a quantitative study of the dependence of the GMR ratio as well as the sensor resistance on the ion dose, which is implanted in the active region of our sensors. These findings are correlated with the decrease of magneto-resistive properties after micro- and nano-structuring by the FIB and reveal the importance of ion damage which limits the applicability of FIB milling to GMR devices in the low μm range. Deposition of a protective layer (50 nm SiO 2 ) on top of the sensor structure before milling leads to a preservation of the magneto-resistive properties after the milling procedure down to sensor dimensions of ∼300 nm. The reduction of the sensor dimensions to the nanometer regime is accompanied by a shift of the GMR curves, and a modification of the saturation behavior. Both effects can be explained by a micromagnetic model including the magnetic interaction of free and pinned layer as well as the effect of the demagnetizing field of the free layer on the sensor behavior. The results demonstrate that the FIB technology can be successfully used to prepare spintronic nanostructures

  6. Heart valve surgery

    Science.gov (United States)

    ... replacement; Valve repair; Heart valve prosthesis; Mechanical valves; Prosthetic valves ... surgery. Your heart valve has been damaged by infection ( endocarditis ). You have received a new heart valve ...

  7. Strength and water-tightness of the closure head and valves of a model cask under high external pressure

    International Nuclear Information System (INIS)

    Terada, O.; Kumada, M.; Hayakawa, T.; Mochizuki, S.; Ohrui, K.

    1978-01-01

    This paper describes experimental research on the strength and water-tightness of the closure head and attached valves of a model cask under high external pressure, in simulation of its having been accidentally lost in the deep sea. Both the external pressure tests and the corrosion tests were carried out using scale models of the closure head of an 80-ton spent-fuel shipping cask, and the full size pressure relief valves and drain valves which were to be attached to the actual cask. Based on the results of the above tests, evaluations were made, and new information was obtained on the pressure-proof strength and water-tightness of the closure head of the cask and the valves. Lastly, research which is being carried on in Japan on the pressure equalizer is also introduced

  8. High-spin nuclear structure studies with radioactive ion beams

    International Nuclear Information System (INIS)

    Baktash, C.

    1992-01-01

    Two important developments in the sixties, namely the advent of heavy-ion accelerators and fabrication of Ge detectors, opened the way for the experimental studies of nuclear properties at high angular momentum. Addition of a new degree of freedom, namely spin, made it possible to observe such fascinating phenomena as occurrences and coexistence of a variety of novel shapes, rise, fall and occasionally rebirth of nuclear collectivity, and disappearance of pairing correlations. Today, with the promise of development of radioactive ion beams (RIB) and construction of the third-generation Ge-detection systems (GAMMASPHERE and EUROBALL), nuclear physicists are poised to explore new and equally fascinating phenomena that have been hitherto inaccessible. With the addition of yet another dimension, namely the isospin, they will be able to observe and verify predictions for exotic shapes as varied as rigid triaxiality, hyperdeformation and triaxial-octupole shapes, or to investigate the T=O pairing correlations. In this paper, the author reviews, separately for neutron-deficient and neutron-rich nuclei, these and a few other new high-spin physics opportunities that may be realized with RIB. Following this discussion, a list of the beam species, intensities and energies that are needed to fulfill these goals is presented. The paper concludes with a description of the experimental techniques and instrumentations that are required for these studies

  9. A remote control valve

    International Nuclear Information System (INIS)

    Cachard, Maurice de; Dumont, Maurice.

    1976-01-01

    This invention concerns a remote control valve for shutting off or distributing a fluid flowing at a high rate and low pressure. Among the different valves at present in use, electric valves are the most recommended for remote control but their reliability is uncertain and they soon become costly when large diameter valves are used. The valve described in this invention does away with this drawback owing to its simplicity and the small number of moving parts, this makes it particularly reliable. It mainly includes: a tubular body fitted with at least one side opening; at least one valve wedge for this opening, coaxial with the body, and mobile; a mobile piston integral with this wedge. Several valves to the specifications of this invention can be fitted in series (a shut-off valve can be used in conjunction with one or more distribution valves). The fitting and maintenance of the valve is very simple owing to its design. It can be fabricated in any material such as metals, alloys, plastics and concrete. The structure of the valve prevents the flowing fluid from coming into contact with the outside environment, thereby making it particularly suitable in the handling of dangerous or corrosive fluids. Finally, the opening and shutting of the valve occurs slowly, thereby doing away with the water hammer effect so frequent in large bore pipes [fr

  10. Resistance calculation of un-fully developed two-phase flow through high differential pressure regulating valves

    International Nuclear Information System (INIS)

    Xu Mingyang; Wang Wenran; Wang Jiaying

    1999-01-01

    To reduce the flow velocity in the high differential pressure regulating valve with labyrinth. A type of complicated valve core structure were designed with tortuous flow path made from reversal double elbows. It is very difficult to calculate the pressure-drop of the un-fully developed two-phase flow under high temperature and pressure which flow through the valve core. A calculation method called 'constant (varing) pressure-drop progressing step by step design method' was developed. The complicated flow path was disintegrated into a series of independent resistance units and with the valve stem end progressing step by step the dimensions of the flow path were designed in accordance with the principle that in every position the total pressure-drop of the valve should amount to that required by the design goal curve. In the course of calculating the total pressure-drop, the valve flow path was also divided into a series of independent resistance units. The experiment results show that design flow characteristics are approximately consistent with the flow characteristics measured in the test

  11. Minimally invasive mitral valve surgery expands the surgical options for high-risks patients.

    Science.gov (United States)

    Petracek, Michael R; Leacche, Marzia; Solenkova, Natalia; Umakanthan, Ramanan; Ahmad, Rashid M; Ball, Stephen K; Hoff, Steven J; Absi, Tarek S; Balaguer, Jorge M; Byrne, John G

    2011-10-01

    A simplified minimally invasive mitral valve surgery (MIMVS) approach avoiding cross-clamping and cardioplegic myocardial arrest using a small (5 cm) right antero-lateral incision was developed. We hypothesized that, in high-risk patients and in patients with prior sternotomy, this approach would yield superior results compared to those predicted by the Society of Thoracic Surgeons (STS) algorithm for standard median sternotomy mitral valve surgery. Five hundred and four consecutive patients (249 males/255 females), median age 65 years (range 20-92 years) underwent MIMVS between 1/06 and 8/09. Median preoperative New York Heart Association function class was 3 (range 1-4). Eighty-two (16%) patients had an ejection fraction ≤35%. Forty-seven (9%) had a STS predicted mortality ≥10%. Under cold fibrillatory arrest (median temperature 28°C) without aortic cross-clamp, mitral valve repair (224/504, 44%) or replacement (280/504, 56%) was performed. Thirty-day mortality for the entire cohort was 2.2% (11/504). In patients with a STS predicted mortality ≥ 10% (range 10%-67%), the observed 30-day mortality was 4% (2/47), lower than the mean STS predicted mortality of 20%. Morbidity in this high-risk group was equally low: 1 of 47 (2%) patients underwent reexploration for bleeding, 1 of 47 (2%) patients suffered a permanent neurologic deficit, none had wound infection. The median length of stay was 8 days (range 1-68 days). This study demonstrates that MIMVS without aortic cross-clamp is reproducible with low mortality and morbidity rates. This approach expands the surgical options for high-risk patients and yields to superior results than the conventional median sternotomy approach.

  12. Heavy gas valves

    Energy Technology Data Exchange (ETDEWEB)

    Steier, L [Vereinigte Armaturen Gesellschaft m.b.H., Mannheim (Germany, F.R.)

    1979-01-01

    Heavy gas valves must comply with special requirements. Apart from absolute safety in operation there are stringent requirements for material, sealing and ease of operation even in the most difficult conditions. Ball valves and single plate pipe gate valves lateral sealing rings have a dual, double sided sealing effect according to the GROVE sealing system. Single plate gate valves with lateral protective plates are suitable preferably for highly contaminated media. Soft sealing gate valves made of cast iron are used for low pressure applications.

  13. Nuclear structure of 94,95Mo at high spins

    International Nuclear Information System (INIS)

    Kharraja, B.; Ghugre, S.S.; Garg, U.; Janssens, R.V.; Carpenter, M.P.; Crowell, B.; Khoo, T.L.; Lauritsen, T.; Nisius, D.; Reviol, W.; Mueller, W.F.; Riedinger, L.L.; Kaczarowski, R.

    1998-01-01

    The high-spin level structures of 94,95 Mo (N=52,53) have been investigated via the 65 Cu( 36 S, αp2n) 94 Mo and 65 Cu( 36 S, αpn) 95 Mo reactions at 142 MeV. The level schemes have been extended up to spin J∼19ℎ and excitation energies E x ∼12 MeV. Spherical shell-model calculations have been performed and compared with the experimental energy levels. The level structure of 94 Mo exhibits a single-particle nature and the higher-angular-momentum states are dominated by the excitation of a g 9/2 neutron across the N=50 shell gap. The level sequences observed in 95 Mo have been interpreted on the basis of the spherical shell model and weak coupling of a d 5/2 or a g 7/2 neutron to the 94 Mo core. copyright 1998 The American Physical Society

  14. PREFACE: Spin Electronics

    Science.gov (United States)

    Dieny, B.; Sousa, R.; Prejbeanu, L.

    2007-04-01

    Conventional electronics has in the past ignored the spin on the electron, however things began to change in 1988 with the discovery of giant magnetoresistance in metallic thin film stacks which led to the development of a new research area, so called spin-electronics. In the last 10 years, spin-electronics has achieved a number of breakthroughs from the point of view of both basic science and application. Materials research has led to several major discoveries: very large tunnel magnetoresistance effects in tunnel junctions with crystalline barriers due to a new spin-filtering mechanism associated with the spin-dependent symmetry of the electron wave functions new magnetic tunnelling barriers leading to spin-dependent tunnelling barrier heights and acting as spin-filters magnetic semiconductors with increasingly high ordering temperature. New phenomena have been predicted and observed: the possibility of acting on the magnetization of a magnetic nanostructure with a spin-polarized current. This effect, due to a transfer of angular momentum between the spin polarized conduction electrons and the local magnetization, can be viewed as the reciprocal of giant or tunnel magnetoresistance. It can be used to switch the magnetization of a magnetic nanostructure or to generate steady magnetic excitations in the system. the possibility of generating and manipulating spin current without charge current by creating non-equilibrium local accumulation of spin up or spin down electrons. The range of applications of spin electronics materials and phenomena is expanding: the first devices based on giant magnetoresistance were the magnetoresistive read-heads for computer disk drives. These heads, introduced in 1998 with current-in plane spin-valves, have evolved towards low resistance tunnel magnetoresistice heads in 2005. Besides magnetic recording technology, these very sensitive magnetoresistive sensors are finding applications in other areas, in particular in biology. magnetic

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

    International Nuclear Information System (INIS)

    Cerkaski, M.; Szymanski, Z.

    1978-01-01

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

  16. Bioprosthetic Valve Fracture to Facilitate Transcatheter Valve-in-Valve Implantation.

    Science.gov (United States)

    Allen, Keith B; Chhatriwalla, Adnan K; Cohen, David J; Saxon, John T; Aggarwal, Sanjeev; Hart, Anthony; Baron, Suzanne; Davis, J Russell; Pak, Alex F; Dvir, Danny; Borkon, A Michael

    2017-11-01

    Valve-in-valve transcatheter aortic valve replacement is less effective in small surgical bioprostheses. We evaluated the feasibility of bioprosthetic valve fracture with a high-pressure balloon to facilitate valve-in-valve transcatheter aortic valve replacement. In vitro bench testing on aortic tissue valves was performed on 19-mm and 21-mm Mitroflow (Sorin, Milan, Italy), Magna and Magna Ease (Edwards Lifesciences, Irvine, CA), Trifecta and Biocor Epic (St. Jude Medical, Minneapolis, MN), and Hancock II and Mosaic (Medtronic, Minneapolis, MN). High-pressure balloons Tru Dilation, Atlas Gold, and Dorado (C.R. Bard, Murray Hill, NJ) were used to determine which valves could be fractured and at what pressure fracture occurred. Mitroflow, Magna, Magna Ease, Mosaic, and Biocor Epic surgical valves were successfully fractured using high-pressures balloon 1 mm larger than the labeled valve size whereas Trifecta and Hancock II surgical valves could not be fractured. Only the internal valve frame was fractured, and the sewing cuff was never disrupted. Manufacturer's rated burst pressures for balloons were exceeded, with fracture pressures ranging from 8 to 24 atmospheres depending on the surgical valve. Testing further demonstrated that fracture facilitated the expansion of previously constrained, underexpanded transcatheter valves (both balloon and self-expanding) to the manufacturer's recommended size. Bench testing demonstrates that the frame of most, but not all, bioprosthetic surgical aortic valves can be fractured using high-pressure balloons. The safety of bioprosthetic valve fracture to optimize valve-in-valve transcatheter aortic valve replacement in small surgical valves requires further clinical investigation. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

  17. High-spin research with HERA [High Energy-Resolution Array

    International Nuclear Information System (INIS)

    Diamond, R.M.

    1987-06-01

    The topic of this report is high spin research with the High Energy Resolution Array (HERA) at Lawrence Berkeley Laboratory. This is a 21 Ge detector system, the first with bismuth germanate (BGO) Compton suppression. The array is described briefly and some of the results obtained during the past year using this detector facility are discussed. Two types of studies are described: observation of superdeformation in the light Nd isotopes, and rotational damping at high spin and excitation energy in the continuum gamma ray spectrum

  18. Valve Disease

    Science.gov (United States)

    ... blood. There are 4 valves in the heart: tricuspid, pulmonary, mitral, and aortic. Two types of problems can disrupt blood flow through the valves: regurgitation or stenosis. Regurgitation is also called insufficiency or incompetence. Regurgitation happens when a valve doesn’ ...

  19. Spin-polaron theory of high-Tc superconductivity: I, spin polarons and high-Tc pairing

    International Nuclear Information System (INIS)

    Wood, R.F.

    1993-06-01

    The concept of a spin polaron is introduced and contrasted with the more familiar ionic polaron picture. A brief review of aspects of ionic bipolaronic superconductivity is given with particular emphasis on the real-space pairing and true Bose condensation characteristics. The formation energy of spin polarons is then calculated in analogy with ionic polarons. The spin-flip energy of a Cu spin in an antiferromagnetically aligned CuO 2 plane is discussed. It is shown that the introduction of holes into the CuO 2 planes will always lead to the destruction of long-range AF ordering due to the formation of spin polarons. The pairing of two spin polarons can be expected because of the reestablishment of local (short-range) AF ordering; the magnitude of the pairing energy is estimated using a simplified model. The paper closes with a brief discussion of the formal theory of spin polarons

  20. Spin transport and relaxation in graphene

    International Nuclear Information System (INIS)

    Han Wei; McCreary, K.M.; Pi, K.; Wang, W.H.; Li Yan; Wen, H.; Chen, J.R.; Kawakami, R.K.

    2012-01-01

    We review our recent work on spin injection, transport and relaxation in graphene. The spin injection and transport in single layer graphene (SLG) were investigated using nonlocal magnetoresistance (MR) measurements. Spin injection was performed using either transparent contacts (Co/SLG) or tunneling contacts (Co/MgO/SLG). With tunneling contacts, the nonlocal MR was increased by a factor of ∼1000 and the spin injection/detection efficiency was greatly enhanced from ∼1% (transparent contacts) to ∼30%. Spin relaxation was investigated on graphene spin valves using nonlocal Hanle measurements. For transparent contacts, the spin lifetime was in the range of 50-100 ps. The effects of surface chemical doping showed that for spin lifetimes in the order of 100 ps, charged impurity scattering (Au) was not the dominant mechanism for spin relaxation. While using tunneling contacts to suppress the contact-induced spin relaxation, we observed the spin lifetimes as long as 771 ps at room temperature, 1.2 ns at 4 K in SLG, and 6.2 ns at 20 K in bilayer graphene (BLG). Furthermore, contrasting spin relaxation behaviors were observed in SLG and BLG. We found that Elliot-Yafet spin relaxation dominated in SLG at low temperatures whereas Dyakonov-Perel spin relaxation dominated in BLG at low temperatures. Gate tunable spin transport was studied using the SLG property of gate tunable conductivity and incorporating different types of contacts (transparent and tunneling contacts). Consistent with theoretical predictions, the nonlocal MR was proportional to the SLG conductivity for transparent contacts and varied inversely with the SLG conductivity for tunneling contacts. Finally, bipolar spin transport in SLG was studied and an electron-hole asymmetry was observed for SLG spin valves with transparent contacts, in which nonlocal MR was roughly independent of DC bias current for electrons, but varied significantly with DC bias current for holes. These results are very important for

  1. Evolution of nuclear collectivity at high spins and temperatures

    International Nuclear Information System (INIS)

    Baktash, C.

    1989-01-01

    In the past few years, we have utilized the Spin Spectrometer and a variety of complementary probes (continuum γrays, proton-γ coincidence spectroscopy and γ decay of GDR) to study the nuclear response to the DIFFERENTIAL effects of increasing spin and temperature for constant values of excitation energy or spin, respectively. In this paper we shall describe two of the experiments that trace the properties of rapidly-rotating nuclei at small to moderate excitation energies. 22 refs., 7 figs

  2. Neutron spin echo and high resolution inelastic spectroscopy

    International Nuclear Information System (INIS)

    Mezei, F.; Hungarian Academy of Sciences, Budapest. Central Research Inst. for Physics)

    1982-01-01

    The principles of neutrons spin echo (NSE) technique are considered. It is shown that the basis of NSE principle is a single step measurement of the change of the neutron velocity in the scattering process. The backscattering soectroscopy and the NSE techniques are compared. The NSF spectrometer is described. It is shown that 0.5 MeV energy resolution achieved in the NSE experiment is about 40 times superior to those achieved by the other techniques. The NSE technique has the unique feature that provides high resolution in neutron energy change independently of the monochromatization of the beam. The NSE instrument not only covers a wider dynamic range on a pulsed source that on a continuous one, but also collects data more efficiently

  3. High spin states in 66,68Ge

    International Nuclear Information System (INIS)

    Hermkens, U.; Becker, F.; Eberth, J.; Freund, S.; Mylaeus, T.; Skoda, S.; Teichert, W.; Werth, A. v.d.

    1992-01-01

    High spin states of 66,68 Ge have been investigated at the FN Tandem accelerator of the University of Koeln via the reactions 40 Ca( 32 S,α2p,4p) 66,68 Ge at a beam energy of 100 MeV and 58 Ni( 16 O,α2p) 68 Ge at 65 MeV. The OSIRIS spectrometer with 12 escape suppressed Ge detectors was used to measure γγ coincidences and γ-ray angular distributions. In 66 Ge ( 68 Ge) 33 (22) new levels were found and 63 (62) new γ-transitions were placed in the level scheme. Both nuclei show a rather complicated but similar excitation pattern, ruled by the interplay of quasiparticle and collective degrees of freedom. The results are compared to the recently published EXVAM calculations for 68 Ge. (orig.)

  4. Observation of high spin states in 117Xe

    International Nuclear Information System (INIS)

    Liu, Z.; Yuan, G.J.; Li, G.S.; Yang, C.X.; Luo, W.D.; Chen, Y.S.

    1995-01-01

    High spin states of 117 Xe have been investigated by means of in-beam γ-ray spectroscopy using the reaction 92 Mo( 28 Si, 2pn) at beam energies of 100 to 120 MeV. The previously known νh 11/2 bands are confirmed and the νg 7/2 favored-signature band is extended up to 47/2 + , in which two band crossings are observed at hω=0.33 and 0.44 MeV, respectively. Two new positive-parity bands have been established, one of which is most likely the νg 7/2 unfavored-signature band. A new transition cascade with irregular level spacings is also observed. (orig.)

  5. High-dose dosimetry using electron spin resonance (ESR) spectroscopy

    International Nuclear Information System (INIS)

    Kojima, Takuji; Tanaka, Ryuichi

    1992-01-01

    An electron spin resonance (ESR) dosimeter capable of measuring large doses of radiation in radiotherapy and radiation processing is outlined. In particular, an alanine/ESR dosimeter is discussed, focusing on the development of elements, the development of the ESR dosimetric system, the application of alanine/ESR dosimeter, and basic researches. Rod elements for gamma radiation and x radiation and film elements for electron beams are described in detail. The following recent applications of the alanine/ESR dosimeter are introduced: using as a transfer dosimeter, applying to various types of radiation, diagnosing the deterioration of radiological materials and equipments, and applying to ESR imaging. The future subjects to be solved in the alanine/ESR dosimetric system are referred to as follows: (1) improvement of highly accurate elements suitable for the measurement of various types of radiation, (2) establishment of sensitive calibration method of the ESR equipment itself, and (3) calibration and standardization of radiation doses. (K.N.) 65 refs

  6. High-frequency EPR on high-spin transition-metal sites

    NARCIS (Netherlands)

    Mathies, Guinevere

    2012-01-01

    The electronic structure of transition-metal sites can be probed by electron-paramagnetic-resonance (EPR) spectroscopy. The study of high-spin transition-metal sites benefits from EPR spectroscopy at frequencies higher than the standard 9.5 GHz. However, high-frequency EPR is a developing field. In

  7. Synchronization and chaos in spin-transfer-torque nano-oscillators coupled via a high-speed operational amplifier

    International Nuclear Information System (INIS)

    Sanid, C; Murugesh, S

    2014-01-01

    We propose a system of two coupled spin-torque nano-oscillators (STNOs), one driver and another response, and demonstrate using numerical studies the synchronization of the response system to the frequency of the driver system. To this end we use a high-speed operational amplifier in the form of a voltage follower, which essentially isolates the drive system from the response system. We find the occurrence of 1 : 1 as well as 2 : 1 synchronization in the system, wherein the oscillators show limit cycle dynamics. An increase in power output is noticed when the two oscillators are locked in 1 : 1 synchronization. Moreover in the crossover region between these two synchronization dynamics we show the existence of chaotic dynamics in the slave system. The coupled dynamics under periodic forcing, using a small ac input current in addition to that of the dc part, is also studied. The slave oscillator is seen to retain its qualitative identity in the parameter space in spite of being fed in, at times, a chaotic signal. Such electrically coupled STNOs will be highly useful in fabricating commercial spin-valve oscillators with high power output, when integrated with other spintronic devices. (paper)

  8. Storing quantum information in spins and high-sensitivity ESR.

    Science.gov (United States)

    Morton, John J L; Bertet, Patrice

    2018-02-01

    Quantum information, encoded within the states of quantum systems, represents a novel and rich form of information which has inspired new types of computers and communications systems. Many diverse electron spin systems have been studied with a view to storing quantum information, including molecular radicals, point defects and impurities in inorganic systems, and quantum dots in semiconductor devices. In these systems, spin coherence times can exceed seconds, single spins can be addressed through electrical and optical methods, and new spin systems with advantageous properties continue to be identified. Spin ensembles strongly coupled to microwave resonators can, in principle, be used to store the coherent states of single microwave photons, enabling so-called microwave quantum memories. We discuss key requirements in realising such memories, including considerations for superconducting resonators whose frequency can be tuned onto resonance with the spins. Finally, progress towards microwave quantum memories and other developments in the field of superconducting quantum devices are being used to push the limits of sensitivity of inductively-detected electron spin resonance. The state-of-the-art currently stands at around 65 spins per Hz, with prospects to scale down to even fewer spins. Copyright © 2017. Published by Elsevier Inc.

  9. Storing quantum information in spins and high-sensitivity ESR

    Science.gov (United States)

    Morton, John J. L.; Bertet, Patrice

    2018-02-01

    Quantum information, encoded within the states of quantum systems, represents a novel and rich form of information which has inspired new types of computers and communications systems. Many diverse electron spin systems have been studied with a view to storing quantum information, including molecular radicals, point defects and impurities in inorganic systems, and quantum dots in semiconductor devices. In these systems, spin coherence times can exceed seconds, single spins can be addressed through electrical and optical methods, and new spin systems with advantageous properties continue to be identified. Spin ensembles strongly coupled to microwave resonators can, in principle, be used to store the coherent states of single microwave photons, enabling so-called microwave quantum memories. We discuss key requirements in realising such memories, including considerations for superconducting resonators whose frequency can be tuned onto resonance with the spins. Finally, progress towards microwave quantum memories and other developments in the field of superconducting quantum devices are being used to push the limits of sensitivity of inductively-detected electron spin resonance. The state-of-the-art currently stands at around 65 spins per √{ Hz } , with prospects to scale down to even fewer spins.

  10. Managing high risk glaucoma with the Ahmed valve implant: 20 years of experience

    Directory of Open Access Journals (Sweden)

    Tryfon Rotsos

    2018-02-01

    Full Text Available AIM: To estimate the efficacy and safety of the Ahmed implant in patients with high risk for failure after glaucoma surgery. METHODS: In 342 eyes of 342 patients with refractory glaucoma, even with application of medical treatment, the Ahmed valve was introduced for intraocular pressure (IOP control, in the period of the last 20y. The nature of glaucoma was neovascular in 162 eyes, pseudophakic or aphakic in 49 eyes, inflammatory in 29 eyes and non working previous antiglaucomatic surgical interventions in 102 eyes. RESULTS: Follow-up ranged from 18 to 120mo with a mean follow-up of 63.2mo. IOP before the operation decreased from 31.6±10.4 mm Hg to 18.3±5.4 mm Hg (no systemic treatment at the end of follow up period. When we compared the IOP values before the operation using ANOVA showed statistically significant difference (P<0.001. The success rate was 85.2% during the first semester, 76.8% at 12mo and 50.3% at the end of follow up period (18 to 120mo after implantation. Success rate was 25.7% in neovascular glaucoma, 63.2% in aphakic glaucoma and 73.8% in non working previous antiglaucomatic surgical interventions. Complications due to the implant were: serous choroidal detachment in 14.8%, blockage of the tube in 2.8%, malposition of the tube in 4.9%, suprachoroidal hemorrhage in 2.1%, cataract progression in 39.6% (phakic eyes, shallow anterior chamber in 9.2%, hyphaema in 28.9%, exposure of valve in 2.6%, exposure of tube in 9.3%, hypotony in 4.9% and conjunctival fibrosis in 41.5%. CONCLUSION: Despite the fact that Ahmed valve implant had suchlike results as other implants concerning the IOP control, complications rate due to hypotony or over filtration in the first days after the intervention are not that frequent as with other valve implants.

  11. High field electron-spin transport and observation of the Dyakonov-Perel spin relaxation of drifting electrons in low temperature-grown gallium arsenide

    International Nuclear Information System (INIS)

    Miah, M. Idrish

    2008-01-01

    High field electron-spin transport in low temperature-grown gallium arsenide is studied. We generate electron spins in the samples by optical pumping. During transport, we observe the Dyakonov-Perel (DP) [M.I. Dyakonov, V.I. Perel, Zh. Eksp. Teor. Fiz. 60 (1971) 1954] spin relaxation of the drifting electrons. The results are discussed and are compared with those obtained in calculations of the DP spin relaxation frequency of the hot electrons. A good agreement is obtained

  12. High field electron-spin transport and observation of the Dyakonov-Perel spin relaxation of drifting electrons in low temperature-grown gallium arsenide

    Energy Technology Data Exchange (ETDEWEB)

    Miah, M. Idrish [Nanoscale Science and Technology Centre, Griffith University, Nathan, Brisbane, QLD 4111 (Australia); Biomolecular and Physical Sciences, Griffith University, Nathan, Brisbane, QLD 4111 (Australia); Department of Physics, University of Chittagong, Chittagong-4331 (Bangladesh)], E-mail: m.miah@griffith.edu.au

    2008-11-17

    High field electron-spin transport in low temperature-grown gallium arsenide is studied. We generate electron spins in the samples by optical pumping. During transport, we observe the Dyakonov-Perel (DP) [M.I. Dyakonov, V.I. Perel, Zh. Eksp. Teor. Fiz. 60 (1971) 1954] spin relaxation of the drifting electrons. The results are discussed and are compared with those obtained in calculations of the DP spin relaxation frequency of the hot electrons. A good agreement is obtained.

  13. Fusion with highly spin polarized HD and D2

    International Nuclear Information System (INIS)

    Honig, A.; Letzring, S.; Skupsky, S.

    1993-01-01

    Our experimental efforts over the past 5 years have been aimed at cazrying out ICF shots with spin-polarized 0 fuel. We successfully prepared polarized 0 in HD, and solved the problems of loading target shells with our carefully prepared isotopic -rnixt.l.l?-es, polarizing them so that the 0 polarization remains metastably frozen-in for about half a day, and carrying out the various cold transfer requirements at Syracuse, where the target is prepared, and at Rochester, where the cold target is inserted fusion chamber. Upon shooting the accurately positioned unpolarized high density cold target, no neutron yield was observed. Inspection inside the OMEGA tank after the shot indicated the absence of neutron yield was dus to mal-timing or insufficient retraction rate of OMEGA'S fast shroud mechanism, resulting in interception of at least 20 of the 24 laser beams by the faulty shroud. In spits of this, all alements of the complex experiment we originally undertook have been successfully demonstrated, and the cold retrieval concepts and methods we developed are being utilized on the ICF upgrades at Rochester and at Livermore. In addition to the solution of the interface problems, we obtained novel results on polymer shell characteristics at low temperatures, and continuation of these experiments is c = ently supported by KLUP. Extensive additional mappings were ca=ied out of nuclear spin relaxation rates of H and D in solid HD in the temperature-magnetic field rangs of 0.01 to 4.2K and 0 - 13 Tesla. New phenomena were discovered, such as association of impurity clustering with very low temperature motion, and inequality of the growth-rate and decay-rate of the magnetization

  14. Fusion with highly spin polarized HD and D2

    International Nuclear Information System (INIS)

    Honig, A.

    1992-01-01

    This report discusses the following topics relating to inertial confinement with spin polarized hydrogen targets: low temperature implementation of mating a target to omega; dilution-refrigerator cold-entry and retrieval system; target shell tensile strength characterization at low temperatures; and proton and deuteron spin-lattice relaxation measurements in HD in the millikelvin temperature range

  15. Elimination of Power Divergences in Consistent Model for Spinless and High-Spin Particle Interactions

    International Nuclear Information System (INIS)

    Kulish, Yu.V.; Rybachuk, E.V.

    2007-01-01

    The currents for the interaction of the massive high-spin boson (J≥1) with two spinless particles are derived. These currents obey the theorem on currents and fields as well as the theorem on current asymptotics. In one-loop approximation the contributions of high-spin boson to the self-energy operator for a spinless particle are calculated. It is shown that in one loop approximation the high-spin boson contributions for any spin J and mass lead to finite self-energy operators of spinless-particle

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

    OpenAIRE

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

    2005-01-01

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

  17. Evaluation and compensation of steady gas flow force on the high-pressure electro-pneumatic servo valve direct-driven by voice coil motor

    International Nuclear Information System (INIS)

    Li, Baoren; Gao, Longlong; Yang, Gang

    2013-01-01

    Highlights: ► A novel energy saving high-pressure electro-pneumatic servo valve is presented. ► An evaluated method for steady gas flow forces on pneumatic valves is proposed. ► Gas jet angles at the orifices for the valve are larger than 69° commonly used. ► The steady gas flow force is strongly nonlinear with valve opening. ► The steady gas flow force is compensated and the aim at energy saving is realized. - Abstract: A novel voice coil motor (VCM) direct drive single stage high-pressure pneumatic servo valve is designed, and then the steady gas flow force acting on the spool of the servo valve is investigated by numerical simulation and experimental methods in this paper. At present, many studies about flow force are concentrated mainly on hydraulic valves, but rarely on pneumatic valves. However, the velocity of gas is up to sonic when high-pressure gas flows through the servo valve orifice. And therefore, the steady gas flow force, generated by high pressure and high speed gas flow, cannot be neglected and is an important disturbance for the VCM direct-drive single stage high-pressure pneumatic servo valve. Consequently, the numerical simulation with computational fluid dynamics (CFD) is adopted to analyze the flow filed, jet angles, and steady gas flow forces for the servo valve with different valve openings and inlet pressures. The experimental study is performed to evaluate and confirm the numerical analysis. Then the compensated approach is proposed to reduce the steady gas flow force for the servo valve, changing the angle of non-metering port designed in the valve sleeve to the spool axis. The results demonstrate that the presented numerical analysis method is validated, the gas jet angle for the servo valve orifice is more than 69° and varies with different spool openings, and the steady gas flow force is nonlinear with valve opening and linear with inlet pressure when the outlet boundary is atmospheric pressure. Moreover, the steady gas

  18. Time-resolved PIV technique for high temporal resolution measurement of mechanical prosthetic aortic valve fluid dynamics.

    Science.gov (United States)

    Kaminsky, R; Morbiducci, U; Rossi, M; Scalise, L; Verdonck, P; Grigioni, M

    2007-02-01

    Prosthetic heart valves (PHVs) have been used to replace diseased native valves for more than five decades. Among these, mechanical PHVs are the most frequently implanted. Unfortunately, these devices still do not achieve ideal behavior and lead to many complications, many of which are related to fluid mechanics. The fluid dynamics of mechanical PHVs are particularly complex and the fine-scale characteristics of such flows call for very accurate experimental techniques. Adequate temporal resolution can be reached by applying time-resolved PIV, a high-resolution dynamic technique which is able to capture detailed chronological changes in the velocity field. The aim of this experimental study is to investigate the evolution of the flow field in a detailed time domain of a commercial bileaflet PHV in a mock-loop mimicking unsteady conditions, by means of time-resolved 2D Particle Image Velocimetry (PIV). The investigated flow field corresponded to the region immediately downstream of the valve plane. Spatial resolution as in "standard" PIV analysis of prosthetic valve fluid dynamics was used. The combination of a Nd:YLF high-repetition-rate double-cavity laser with a high frame rate CMOS camera allowed a detailed, highly temporally resolved acquisition (up to 10000 fps depending on the resolution) of the flow downstream of the PHV. Features that were observed include the non-homogeneity and unsteadiness of the phenomenon and the presence of large-scale vortices within the field, especially in the wake of the valve leaflets. Furthermore, we observed that highly temporally cycle-resolved analysis allowed the different behaviors exhibited by the bileaflet valve at closure to be captured in different acquired cardiac cycles. By accurately capturing hemodynamically relevant time scales of motion, time-resolved PIV characterization can realistically be expected to help designers in improving PHV performance and in furnishing comprehensive validation with experimental data

  19. Tight valve

    International Nuclear Information System (INIS)

    Guedj, F.

    1987-01-01

    This sealed valve is made with a valve seat, an axial valve with a rod fixed to its upper end, a thick bell surrounding the rod and welded by a thin join on the valve casing, a threated ring screwed onto the upper end of the rod and a magnet or electromagnet rotating the ring outside the bell [fr

  20. Cost-effectiveness of transcatheter aortic valve replacement compared with surgical aortic valve replacement in high-risk patients with severe aortic stenosis: results of the PARTNER (Placement of Aortic Transcatheter Valves) trial (Cohort A).

    Science.gov (United States)

    Reynolds, Matthew R; Magnuson, Elizabeth A; Lei, Yang; Wang, Kaijun; Vilain, Katherine; Li, Haiyan; Walczak, Joshua; Pinto, Duane S; Thourani, Vinod H; Svensson, Lars G; Mack, Michael J; Miller, D Craig; Satler, Lowell E; Bavaria, Joseph; Smith, Craig R; Leon, Martin B; Cohen, David J

    2012-12-25

    The aim of this study was to evaluate the cost-effectiveness of transcatheter aortic valve replacement (TAVR) compared with surgical aortic valve replacement (AVR) for patients with severe aortic stenosis and high surgical risk. TAVR is an alternative to AVR for patients with severe aortic stenosis and high surgical risk. We performed a formal economic analysis based on cost, quality of life, and survival data collected in the PARTNER A (Placement of Aortic Transcatheter Valves) trial in which patients with severe aortic stenosis and high surgical risk were randomized to TAVR or AVR. Cumulative 12-month costs (assessed from a U.S. societal perspective) and quality-adjusted life-years (QALYs) were compared separately for the transfemoral (TF) and transapical (TA) cohorts. Although 12-month costs and QALYs were similar for TAVR and AVR in the overall population, there were important differences when results were stratified by access site. In the TF cohort, total 12-month costs were slightly lower with TAVR and QALYs were slightly higher such that TF-TAVR was economically dominant compared with AVR in the base case and economically attractive (incremental cost-effectiveness ratio economically dominated by AVR in the base case and economically attractive in only 7.1% of replicates. In the PARTNER trial, TAVR was an economically attractive strategy compared with AVR for patients suitable for TF access. Future studies are necessary to determine whether improved experience and outcomes with TA-TAVR can improve its cost-effectiveness relative to AVR. Copyright © 2012 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.

  1. Anisotropic spin relaxation in graphene

    NARCIS (Netherlands)

    Tombros, N.; Tanabe, S.; Veligura, A.; Jozsa, C.; Popinciuc, M.; Jonkman, H. T.; van Wees, B. J.

    2008-01-01

    Spin relaxation in graphene is investigated in electrical graphene spin valve devices in the nonlocal geometry. Ferromagnetic electrodes with in-plane magnetizations inject spins parallel to the graphene layer. They are subject to Hanle spin precession under a magnetic field B applied perpendicular

  2. Magnetic proximity control of spin currents and giant spin accumulation in graphene

    Science.gov (United States)

    Singh, Simranjeet

    Two dimensional (2D) materials provide a unique platform to explore the full potential of magnetic proximity driven phenomena. We will present the experimental study showing the strong modulation of spin currents in graphene layers by controlling the direction of the exchange field due to the ferromagnetic-insulator (FMI) magnetization in graphene/FMI heterostructures. Owing to clean interfaces, a strong magnetic exchange coupling leads to the experimental observation of complete spin modulation at low externally applied magnetic fields in short graphene channels. We also discover that the graphene spin current can be fully dephased by randomly fluctuating exchange fields. This is manifested as an unusually strong temperature dependence of the non-local spin signals in graphene, which is due to spin relaxation by thermally-induced transverse fluctuations of the FMI magnetization. Additionally, it has been a challenge to grow a smooth, robust and pin-hole free tunnel barriers on graphene, which can withstand large current densities for efficient electrical spin injection. We have experimentally demonstrated giant spin accumulation in graphene lateral spin valves employing SrO tunnel barriers. Nonlocal spin signals, as large as 2 mV, are observed in graphene lateral spin valves at room temperature. This high spin accumulations observed using SrO tunnel barriers puts graphene on the roadmap for exploring the possibility of achieving a non-local magnetization switching due to the spin torque from electrically injected spins. Financial support from ONR (No. N00014-14-1-0350), NSF (No. DMR-1310661), and C-SPIN, one of the six SRC STARnet Centers, sponsored by MARCO and DARPA.

  3. Low noise control valve

    International Nuclear Information System (INIS)

    Christie, R.S.

    1975-01-01

    Noise is one of the problems associated with the use of any type of control valve in systems involving the flow of fluids. The advent of OSHA standards has prompted control valve manufacturers to design valves with special trim to lower the sound pressure level to meet these standards. However, these levels are in some cases too high, particularly when a valve must be located in or near an area where people are working at tasks requiring a high degree of concentration. Such locations are found around and near research devices and in laboratory-office areas. This paper describes a type of fluid control device presently being used at PPL as a bypass control valve in deionized water systems and designed to reduce sound pressure levels considerably below OSHA standards. Details of the design and construction of this constant pressure drop variable flow control valve are contained in the text and are shown in photographs and drawings. Test data taken are included

  4. Large spin accumulation due to spin-charge coupling across a break-junction

    Science.gov (United States)

    Chen, Shuhan; Zou, Han; Chui, Siu-Tat; Ji, Yi

    2013-03-01

    We investigate large spin signals in break-junction nonlocal spin valves (NLSV). The break-junction is a nanometer-sized vacuum tunneling gap between the spin detector and the nonmagnetic channel, formed by electro-static discharge. The spin signals can be either inverted or non-inverted and the magnitudes are much larger than those of standard NLSV. Spin signals with high percentage values (10% - 0%) have been observed. When the frequency of the a.c. modulation is varied, the absolute magnitudes of signals remain the same although the percentage values change. These observations affirm the nonlocal nature of the measurements and rule out local magnetoresistive effects. Owing to the spin-charge coupling across the break-junction, the spin accumulation in a ferromagnet splits into two terms. One term decays on the charge screening length (0.1 nm) and the other decays on the spin diffusion length (10 nm nm). The magnitude of the former is proportional to the resistance of the junction. Therefore a highly resistive break-junction leads to a large spin accumulation and thereby a large spin signal. The signs of the spin signal are determined by the relationship between spin-dependent conductivities, diffusion constants, and density of states of the ferromagnet. This work was supported by US DOE grant No. DE-FG02-07ER46374.

  5. High-fidelity state transfer over an unmodulated linear XY spin chain

    International Nuclear Information System (INIS)

    Bishop, C. Allen; Ou Yongcheng; Byrd, Mark S.; Wang Zhaoming

    2010-01-01

    We provide a class of initial encodings that can be sent with a high fidelity over an unmodulated, linear, XY spin chain. As an example, an average fidelity of 96% can be obtained using an 11-spin encoding to transmit a state over a chain containing 10 000 spins. An analysis of the magnetic-field dependence is given, and conditions for field optimization are provided.

  6. Spiral spin state in high-temperature copper-oxide superconductors: Evidence from neutron scattering measurements

    DEFF Research Database (Denmark)

    Lindgård, Per-Anker

    2005-01-01

    An effective spiral spin phase ground state provides a new paradigm for the high-temperature superconducting cuprates. It accounts for the recent neutron scattering observations of spin excitations regarding both the energy dispersion and the intensities, including the "universal" rotation by 45...... model. The form of the exchange interaction function reveals the effects of the Fermi surface, and the unique shape predicts large quantum spin fluctuations in the ground state....

  7. Decoupling Analysis on Pressure Fluctuation and Needle Valve Response for High Pressure Common Rail Injector

    Directory of Open Access Journals (Sweden)

    Hao Wang

    2017-01-01

    Full Text Available In the process of multiple injections, the influence of different injections makes the controlling of cycle fuel injection quantity more difficult. The high pressure common rail (HPCR simulation model is established in AMESim environment. Through the method of combining numerical simulation and experiment test, it is found that the strong coupling of pressure fluctuation and needle valve response is the fundamental reason, which leads to the fluctuation of main injection fuel quantity (MIFQ with dwell time (DT. The result shows that the largest fluctuation quantity is 3.6mm3 when the reference value of main injection is 60.0mm3. Non-damping LC hydraulic system model is also established. Through the analysis of the model, reducing the length-diameter ratio of internal oil duct and the delivery chamber volume are decoupling methods to the strong coupling.

  8. New materials research for high spin polarized current

    International Nuclear Information System (INIS)

    Tezuka, Nobuki

    2012-01-01

    The author reports here a thorough investigation of structural and magnetic properties of Co 2 FeAl 0.5 Si 0.5 Heusler alloy films, and the tunnel magnetoresistance effect for junctions with Co 2 FeAl 0.5 Si 0.5 electrodes, spin injection into GaAs semiconductor from Co 2 FeAl 0.5 Si 0.5 , and spin filtering phenomena for junctions with CoFe 2 O 4 ferrite barrier. It was observed that tunnel magnetoresistance ratio up to 832%(386%) at 9 K (room temperature), which corresponds to the tunnel spin polarization of 0.90 (0.81) for the junctions using Co 2 FeAl 0.5 Si 0.5 Heusler electrodes by optimizing the fabrication condition. It was also found that the tunnel magnetoresistance ratio are almost the same between the junctions with Co 2 FeAl 0.5 Si 0.5 Heusler electrodes on Cr buffered (1 0 0) and (1 1 0) MgO substrates, which indicates that tunnel spin polarization of Co 2 FeAl 0.5 Si 0.5 for these two direction are almost the same. The next part of this paper is a spin filtering effect using a Co ferrite. The spin filtering effect was observed through a thin Co-ferrite barrier. The inverse type tunnel magnetoresistance ratio of −124% measured at 10 K was obtained. The inverse type magnetoresistance suggests the negative spin polarization of Co-ferrite barrier. The magnetoresistance ratio of −124% corresponds to the spin polarization of −0.77 by the Co-ferrite barrier. The last part is devoted to the spin injection from Co 2 FeAl 0.5 Si 0.5 into GaAs. The spin injection signal was clearly obtained by three terminal Hanle measurement. The spin relaxation time was estimated to be 380 ps measured at 5 K.

  9. Thrombocytopenia in Moderate- to High-Risk Sutureless Aortic Valve Replacement

    Directory of Open Access Journals (Sweden)

    Puwadon Thitivaraporn

    2018-06-01

    Full Text Available Background : This study aimed to compare preliminary data on the outcomes of sutureless aortic valve replacement (SU-AVR with those of aortic valve replacement (AVR. Methods : We conducted a retrospective study of SU-AVR in moderate- to high-risk patients from 2013 to 2016. Matching was performed at a 1:1 ratio using the Society of Thoracic Surgeons predicted risk of mortality score with sex and age. The primary outcome was 30-day mortality. The secondary outcomes were operative outcomes and complications. Results : A total of 277 patients were studied. Ten patients (50% males; median age, 81.5 years underwent SU-AVR. Postoperative echocardiography showed impressive outcomes in the SU-AVR group. The 30-day mortality was 10% in both groups. In our study, the patients in the SU-AVR group developed postoperative thrombocytopenia. Platelet counts decreased from 225X103 /μL preoperatively to 94.5, 54.5, and 50.1X10 3/μL on postoperative days 1, 2, and 3, respectively, showing significant differences compared with the AVR group (p=0.04, p=0.16, and p=0.20, respectively. The median amount of platelet transfusion was higher in the AVR group (12.5 vs. 0 units, p=0.052. Conclusion : There was no difference in the 30-day mortality of moderate- to high-risk patients depending on whether they underwent SU-AVR or AVR. Although SU-AVR is associated with favorable cardiopulmonary bypass and cross-clamp times, it may be associated with postoperative thrombocytopenia.

  10. Beneficial Effects of High-Density Lipoproteins on Acquired von Willebrand Syndrome in Aortic Valve Stenosis.

    Science.gov (United States)

    Gebhard, C; Maafi, F; Stähli, B E; Bonnefoy, A; Gebhard, C E; Nachar, W; de Oliveira Moraes, A Benjamim; Mecteau, M; Mihalache-Avram, T; Lavoie, V; Kernaleguen, A E; Shi, Y; Busseuil, D; Chabot-Blanchet, M; Perrault, L P; Rhainds, D; Rhéaume, E; Tardif, J C

    2018-02-01

     Infusions of apolipoprotein A-I (apoA-I), the major protein component of high-density lipoproteins (HDL), result in aortic valve stenosis (AVS) regression in experimental models. Severe AVS can be complicated by acquired von Willebrand syndrome, a haemorrhagic disorder associated with loss of high-molecular-weight von Willebrand factor (vWF) multimers (HMWM), the latter being a consequence of increased shear stress and enhanced vWF-cleaving protease (ADAMTS-13) activity. Although antithrombotic actions of HDL have been described, its effects on ADAMTS-13 and vWF in AVS are unknown.  We assessed ADAMTS-13 activity in plasma derived from a rabbit model of AVS ( n  = 29) as well as in plasma collected from 64 patients with severe AVS (age 65.0 ± 10.4 years, 44 males) undergoing aortic valve replacement (AVR). In both human and rabbit AVS plasma, ADAMTS-13 activity was higher than that in controls ( p  AVS patients had less HMWM than controls (66.3 ± 27.2% vs. 97.2 ± 24.1%, p  AVS rabbits as compared with the placebo group (2.0 ± 0.5 RFU/sec vs. 3.8 ± 0.4 RFU/sec, p  AVS ( r  = -0.3, p  = 0.045).  Our data indicate that HDL levels are associated with reduced ADAMTS-13 activity and increased HMWM. HDL-based therapies may reduce the haematologic abnormalities of the acquired von Willebrand syndrome in AVS. Schattauer GmbH Stuttgart.

  11. Long-term followup of bilateral high (Sober) urinary diversion in patients with posterior urethral valves and its effect on bladder function

    NARCIS (Netherlands)

    Ghanem, MA; Nijman, RJM

    Purpose: Although valve ablation is the treatment of choice in patients with posterior urethral valves (PLTV), temporary high (ureterostomy) diversion remains controversial. In this study we evaluated the effect of bilateral Sober high urinary diversion on renal and bladder function. Materials and

  12. High spin states and Yrast isomers in 211Rn

    International Nuclear Information System (INIS)

    Poletti, A.R.; Dracoulis, G.D.; Fahlander, C.; Morrison, I.

    1981-01-01

    Excited states in 211 Rn with spins up to 53/2 have been identified using (HI,xn) reactions and γ-ray techniques. A shell model calculation can reproduce the ordering of the yrast sequence up to spin 41/2 - . Several yrast isomers have been identified. Enhanced E3 transitions are observed and their systematic occurrence in this region discussed. The influence of the neutron hole, and possible core excitations on the effective moment of inertia are also pointed out

  13. High spin states and yrast isomers in 211Rn

    International Nuclear Information System (INIS)

    Poletti, A.R.; Dracoulis, G.D.; Fahlander, C.; Morrison, I.

    1980-12-01

    Excited states in 211 Rn with spins up to 53/2 have been identified using (HI,xn) reactions and γ-ray techniques. A shell model calculation can reproduce the ordering of the yrast sequence up to spin 41/2. Several yrast isomers have been identified. Enhanced E3 transitions are observed and their systematic occurrence in this region discussed. The influence of the neutron hole, and possible core excitations on the effective moment of inertia are also pointed out

  14. High signal intensity of fat on fast spin echo imaging

    International Nuclear Information System (INIS)

    Ogura, Akio; Yamazaki, Masaru; Hongoh, Takaharu; Inoue, Hiroshi; Ishikuro, Akihiro

    2000-01-01

    The fast spin echo (FSE) technique of producing T 2 -weighted images in greatly reduced imaging times has recently been used for routine clinical study. FSE images show contrast that is very similar in most tissues to that of conventional SE images. However, fat shows a high signal intensity that is influenced by j-coupling and the magnetization transfer effect. The purpose of this study was to assess whether the higher signal intensity of fat is different among MRI systems and to examine the effects of j-coupling and magnetization transfer on the high signal intensity of fat on FSE. The contrast in signal intensity between fat and water was measured for various echo train lengths (ETL) with and without multislicing on FSE using a contrast phantom. Measurements were obtained with four different MRI systems. In addition, the effective T 2 values of fat were calculated for the above conditions. Results indicated that contrast for fat and water was reduced with increased ETL and by using multislicing and was different among the four MRI systems. The effective T 2 values of fat were extended for increased ETL and were not dependent on multislicing. They also differed among the four MRI systems. The extent of effective T 2 values was affected by j-coupling. In this study, it was indicated that the degree of the high signal intensity of fat on FSE differed for different MRI systems. In addition, the reasons for the high signal intensity of fat on FSE were related to the effects of j-coupling and magnetization transfer. (author)

  15. Nuclear structure at high-spin and large-deformation

    International Nuclear Information System (INIS)

    Shimizu, Yoshifumi R.

    2000-01-01

    Atomic nucleus is a finite quantal system and shows various marvelous features. One of the purposes of the nuclear structure study is to understand such features from a microscopic viewpoint of nuclear many-body problem. Recently, it is becoming possible to explore nuclear states under 'extreme conditions', which are far different from the usual ground states of stable nuclei, and new aspects of such unstable nuclei attract our interests. In this lecture, I would like to discuss the nuclear structure in the limit of rapid rotation, or the extreme states with very large angular momenta, which became accessible by recent advent of large arrays of gamma-ray detecting system; these devices are extremely useful to measure coincident multiple γ-rays following heavy-ion fusion reactions. Including such experimental aspects as how to detect the nuclear rotational states, I review physics of high-spin states starting from the elementary subjects of nuclear structure study. In would like also to discuss the extreme states with very large nuclear deformation, which are easily realized in rapidly rotating nuclei. (author)

  16. Gyromagnetic factors for high spin states in the actinides

    International Nuclear Information System (INIS)

    Ring, P.

    1984-01-01

    The cranked Hartree-Fock-Bogoliubov theory was used for a systematic investigation of gyromagnetic factors in the yrast states of even-even actinide nuclei. The theory used was the most simplified version with fixed deformation and gap parameters, that is, so-called rotating shell model. The gyromagnetic factor g and the contribution gsub(p) and gsub(n) were obtained for a large number of nuclei in the actinide region. The aligned angular momenta for protons and for neutrons are shown in the same actinide region. The general behaviour of g-factor was able to be understood in terms of simple rules: (i) For fixed proton number, neutron alignment becomes more difficult with increasing the neutron number, and vice versa. (ii) A sudden neutron alignment was observed for N=140 and N=146, and a sudden proton alignment was also observed for Z=94. The alignment between these critical numbers was smooth. The pattern obtained for the values of the aligned angular momentum was clearly reflected to the g-factor, and it provided an excellent tool to study the structure of level in the high spin region. (Asami, T.)

  17. High spin exotic states and new method for pairing energy

    International Nuclear Information System (INIS)

    Molique, H.

    1996-01-01

    We present a new method called 'PSY-MB', initially developed in the framework of abstract group theory for the solution of the problem of strongly interacting multi-fermionic systems with particular to systems in an external rotating field. The validity of the new method (PSY-MB) is tested on model Hamiltonians. A detailed comparison between the obtained solutions and the exact ones is performed. The new method is used in the study of realistic nuclear Hamiltonians based on the Woods-Saxon potential within the cranking approximation to study the influence of residual monopole pairing interactions in the rare-earth mass region. In parallel with this new technique we present original results obtained with the Woods-Saxon mean-field and the self-consistent Hartree-Fock approximation in order to investigate such exotic effects as octupole deformations and hexadecapole C 4 -polarizing deformations in the framework of high-spin physics. By developing these three approaches in one single work we prepare the ground for the nuclear structure calculations of the new generation - where the residual two-body interactions are taken into account also in the weak pairing limit. (author)

  18. A new high-spin isomer in {sup 195}Bi

    Energy Technology Data Exchange (ETDEWEB)

    Roy, T.; Mukherjee, G.; Rana, T.K.; Bhattacharya, Soumik; Asgar, Md.A.; Bhattacharya, C.; Bhattacharya, S.; Bhattacharyya, S.; Pai, H. [Variable Energy Cyclotron Centre, Kolkata (India); Madhavan, N.; Bala, I.; Gehlot, J.; Gurjar, R.K.; Jhingan, A.; Kumar, R.; Muralithar, S.; Nath, S.; Singh, R.P.; Varughese, T. [Inter University Acclerator Centre, New Delhi (India); Basu, K.; Bhattacharjee, S.S.; Ghugre, S.S.; Raut, R.; Sinha, A.K. [UGC-DAE-CSR Kolkata Centre, Kolkata (India); Palit, R. [Tata Institute of Fundamental Research, Department of Nuclear and Atomic Physics, Mumbai (India)

    2015-11-15

    A new high-spin isomer has been identified in {sup 195}Bi at the focal plane of the HYbrid Recoil mass Analyser (HYRA) used in the gas-filled mode. The fusion evaporation reactions {sup 169}Tm ({sup 30}Si, x n) {sup 193,} {sup 195}Bi were used with the beam energies on targets of 168 and 146MeV for 6n and 4n channels, respectively. The evaporation residues, separated from the fission fragments, and their decays were detected at the focal plane of HYRA using MWPC, Si-Pad and clover HPGe detectors. The half-life of the new isomer in {sup 195}Bi has been measured to be 1.6(1) μs. The configuration of the new isomer has been proposed and compared with the other isomers in this region. The Total Routhian Surface (TRS) calculations for the three-quasiparticle configurations corresponding to the new isomer suggest an oblate deformation for this isomeric state. The same calculations for different configurations in {sup 195}Bi and for the even-even {sup 194}Pb core indicate that the proton i{sub 13/2} orbital has a large shape driving effect towards oblate shape in these nuclei. (orig.)

  19. Observations of high spin states in {sup 179}Au

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter, M.P.; Ahmad, I.; Blumenthal, D.J. [and others

    1995-08-01

    As part of a current study on the properties of the {pi} i{sub 13/2} intruder state in the A = 175-190 region, we conducted an experiment at ATLAS to observe high spin states in {sup 179}Au utilizing the reaction {sup 144}Sm({sup 40}Ar,p4n) at beam energies of 207 MeV and 215 MeV. To aid in the identification of {sup 179}Au, and to filter out the large amount of events from fission by-products, the Fragment Mass Analyzer was utilized in conjunction with ten Compton-suppression germanium detectors. In total, 11 x 10{sup 6} {gamma}-{gamma} and 4 x 10{sup 5} {gamma}-recoil events were collected. By comparing {gamma}-rays in coincidence with an A = 179 recoil mass gate and {gamma}-rays in coincidence with Au K{alpha} and K{beta} X-rays, ten {gamma}-rays were identified as belonging to {sup 179}Au. Based on {gamma}-ray coincidence relationships and on comparisons with neighboring odd-A Au nuclei, we constructed a tentative level scheme and assigned a rotational-like sequence to the {pi} i{sub 13/2} proton configuration.

  20. High-fidelity adiabatic inversion of a {sup 31}P electron spin qubit in natural silicon

    Energy Technology Data Exchange (ETDEWEB)

    Laucht, Arne, E-mail: a.laucht@unsw.edu.au; Kalra, Rachpon; Muhonen, Juha T.; Dehollain, Juan P.; Mohiyaddin, Fahd A.; Hudson, Fay; Dzurak, Andrew S.; Morello, Andrea [Centre for Quantum Computation and Communication Technology, School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, New South Wales 2052 (Australia); McCallum, Jeffrey C.; Jamieson, David N. [Centre for Quantum Computation and Communication Technology, School of Physics, University of Melbourne, Melbourne, Victoria 3010 (Australia)

    2014-03-03

    The main limitation to the high-fidelity quantum control of spins in semiconductors is the presence of strongly fluctuating fields arising from the nuclear spin bath of the host material. We demonstrate here a substantial improvement in single-qubit inversion fidelities for an electron spin qubit bound to a {sup 31}P atom in natural silicon, by applying adiabatic sweeps instead of narrow-band pulses. We achieve an inversion fidelity of 97%, and we observe signatures in the spin resonance spectra and the spin coherence time that are consistent with the presence of an additional exchange-coupled donor. This work highlights the effectiveness of simple adiabatic inversion techniques for spin control in fluctuating environments.

  1. High performance current and spin diode of atomic carbon chain between transversely symmetric ribbon electrodes.

    Science.gov (United States)

    Dong, Yao-Jun; Wang, Xue-Feng; Yang, Shuo-Wang; Wu, Xue-Mei

    2014-08-21

    We demonstrate that giant current and high spin rectification ratios can be achieved in atomic carbon chain devices connected between two symmetric ferromagnetic zigzag-graphene-nanoribbon electrodes. The spin dependent transport simulation is carried out by density functional theory combined with the non-equilibrium Green's function method. It is found that the transverse symmetries of the electronic wave functions in the nanoribbons and the carbon chain are critical to the spin transport modes. In the parallel magnetization configuration of two electrodes, pure spin current is observed in both linear and nonlinear regions. However, in the antiparallel configuration, the spin-up (down) current is prohibited under the positive (negative) voltage bias, which results in a spin rectification ratio of order 10(4). When edge carbon atoms are substituted with boron atoms to suppress the edge magnetization in one of the electrodes, we obtain a diode with current rectification ratio over 10(6).

  2. Optical-coupling nuclear spin maser under highly stabilized low static field

    Energy Technology Data Exchange (ETDEWEB)

    Yoshimi, A., E-mail: yoshimi@ribf.riken.jp [RIKEN Nishina Center (Japan); Inoue, T.; Uchida, M.; Hatakeyama, N.; Asahi, K. [Tokyo Institute of Technology, Department of Physics (Japan)

    2008-01-15

    A nuclear spin maser of a new type, that employs a feedback scheme based on optical nuclear spin detection, has been fabricated. The spin maser is operated at a low static field of 30 mG by using the optical detection method. The frequency stability and precision of the spin maser have been improved by a highly stabilized current source for the static magnetic field. An experimental setup to search for an electric dipole moment (EDM) in {sup 129}Xe atom is being developed.

  3. Check valve

    Science.gov (United States)

    Upton, H.A.; Garcia, P.

    1999-08-24

    A check valve for use in a GDCS of a nuclear reactor and having a motor driven disk including a rotatable armature for rotating the check valve disk over its entire range of motion is described. In one embodiment, the check valve includes a valve body having a coolant flow channel extending therethrough. The coolant flow channel includes an inlet end and an outlet end. A valve body seat is located on an inner surface of the valve body. The check valve further includes a disk assembly, sometimes referred to as the motor driven disc, having a counterweight and a disk shaped valve. The disk valve includes a disk base having a seat for seating with the valve body seat. The disk assembly further includes a first hinge pin member which extends at least partially through the disk assembly and is engaged to the disk. The disk valve is rotatable relative to the first hinge pin member. The check valve also includes a motor having a stator frame with a stator bore therein. An armature is rotatably positioned within the stator bore and the armature is coupled to the disk valve to cause the disk valve to rotate about its full range of motion. 5 figs.

  4. Check valve

    International Nuclear Information System (INIS)

    Upton, H.A.; Garcia, P.

    1999-01-01

    A check valve for use in a GDCS of a nuclear reactor and having a motor driven disk including a rotatable armature for rotating the check valve disk over its entire range of motion is described. In one embodiment, the check valve includes a valve body having a coolant flow channel extending therethrough. The coolant flow channel includes an inlet end and an outlet end. A valve body seat is located on an inner surface of the valve body. The check valve further includes a disk assembly, sometimes referred to as the motor driven disc, having a counterweight and a disk shaped valve. The disk valve includes a disk base having a seat for seating with the valve body seat. The disk assembly further includes a first hinge pin member which extends at least partially through the disk assembly and is engaged to the disk. The disk valve is rotatable relative to the first hinge pin member. The check valve also includes a motor having a stator frame with a stator bore therein. An armature is rotatably positioned within the stator bore and the armature is coupled to the disk valve to cause the disk valve to rotate about its full range of motion. 5 figs

  5. Fusion with highly spin polarized HD and D2

    International Nuclear Information System (INIS)

    Honig, A.; Letzring, S.; Skupsky, S.

    1993-01-01

    The experimental efforts over the past 5 years have been aimed at carrying out ICF shots with spin-polarized D fuel. The authors successfully prepared polarized D in HD, and solved the problems of loading target shells with their carefully prepared isotopic mixtures, polarizing them so that the D polarization remains metastably frozen-in for about half a day, and carrying out the various cold transfer requirements at Syracuse, where the target is prepared, and at Rochester, where the cold target is inserted into the OMEGA fusion chamber. A principal concern during this past year was overcoming difficulties encountered in maintaining the integrity of the fragile cold target during the multitude of cold-transfers required for the experiment. These difficulties arose from insufficient rigidity of the cold transfer systems, which were constrained to be of small diameter by the narrow central access bore of the dilution refrigerator, and were exacerbated by the multitude of required target shell manipulations between different environments, each with different coupling geometry, including target shell permeation, polarization, storage, transport, retrieval and insertion into OMEGA. The authors did solve all of these problems, and were able to position a cold, high density but unpolarized target with required precision in OMEGA. Upon shooting the accurately positioned unpolarized high density cold target, no neutron yield was observed. Inspection inside the OMEGA tank after the shot indicated the absence of neutron yield was due to mal-timing or insufficient retraction rate of OMEGA's fast shroud mechanism, resulting in interception of at least 20 of the 24 laser beams by the faulty shroud. In spite of this, all elements of the complex experiment the authors originally undertook have been successfully demonstrated, and the cold retrieval concepts and methods they developed are being utilized on the ICF upgrades at Rochester and at Livermore

  6. High-performance spinning device for DVD-based micromechanical signal transduction

    DEFF Research Database (Denmark)

    Hwu, En-Te; Chen, Ching-Hsiu; Bosco, Filippo

    2013-01-01

    Here we report a high-throughput spinning device for nanometric scale measurements of microstructures with instrumentation details and experimental results. The readout technology implemented in the designed disc-like device is based on a DVD data storage optical pick-up unit (OPU). With a spinning...

  7. High-spin isomer in 211Rn, and the shape of the yrast line

    International Nuclear Information System (INIS)

    Dracoulis, G.D.; Fahlander, C.; Poletti, A.R.

    1981-08-01

    High spin yrast states in 211 Rn have been identified. A 61/2 - , 380 ns isomer found at 8856 keV is characterised as a core-excited configuration. The average shape of the yrast line shows a smooth behaviour with spin, in contrast to its neighbour 212 Rn. This difference is attributed to the presence of the neutron hole

  8. Nuclear shape transitions and some properties of aligned-particle configurations at high spin

    International Nuclear Information System (INIS)

    Koo, T.L.; Chowdhury, P.; Emling, H.

    1982-01-01

    Two topics are addressed in this paper. First, we discuss the variation of shapes with spin and neutron number for nuclei in the N approx. = 88 transitional region. Second, we present comments on the feeding times of very high spin single-particle yrast states

  9. Interplay between spin polarization and color superconductivity in high density quark matter

    DEFF Research Database (Denmark)

    Tsue, Yasuhiko; da Providência, João; Providência, Constança

    2013-01-01

    Here, it is suggested that a four-point interaction of the tensor type may lead to spin polarization in quark matter at high density. It is found that the two-flavor superconducting phase and the spin polarized phase correspond to distinct local minima of a certain generalized thermodynamical pot...

  10. Topics on frustrated spin systems and high-temperature superconductors

    International Nuclear Information System (INIS)

    Lu Yong.

    1990-01-01

    The numerical study of frustrated spin systems using the Monte Carlo simulation method and the analytic study of fluctuation phenomenon of the thermoelectric power near the superconducting transition using Green's function techniques are presented. The first frustrated system considered is the B-site antiferromagnetic (AF) spinel. Based on an Ising model, various thermodynamic and magnetic properties were studied for both the fully frustrated structure and partially frustrated cases of a small tetragonal distortion. When fully frustrated, an interesting short-range order and some unusual scaling behavior were obtained. The other frustrated spin system studied is the magnetic phase of YBa 2 Cu 3 O 6+x via a classical spin model, with appropriate anisotropic exchange couplings and randomly located spins of distribution probability as a function of x. There is a first order boundary between Type 1 and Type 2 in the Ising case, while there is no real phase boundary in the cases of continuous spin. In the study on the thermopower fluctuation, the thermopower was determined by the linear response of the electric and heat currents to an electric field, and the linear responses were in turn calculated from correlation functions of the current

  11. Magnetic Nanostructures Spin Dynamics and Spin Transport

    CERN Document Server

    Farle, Michael

    2013-01-01

    Nanomagnetism and spintronics is a rapidly expanding and increasingly important field of research with many applications already on the market and many more to be expected in the near future. This field started in the mid-1980s with the discovery of the GMR effect, recently awarded with the Nobel prize to Albert Fert and Peter Grünberg. The present volume covers the most important and most timely aspects of magnetic heterostructures, including spin torque effects, spin injection, spin transport, spin fluctuations, proximity effects, and electrical control of spin valves. The chapters are written by internationally recognized experts in their respective fields and provide an overview of the latest status.

  12. High spin polarization and the origin of unique ferromagnetic ground state in CuFeSb

    International Nuclear Information System (INIS)

    Sirohi, Anshu; Saha, Preetha; Gayen, Sirshendu; Gaurav, Abhishek; Jyotsna, Shubhra; Sheet, Goutam; Singh, Chandan K.; Kabir, Mukul; Thakur, Gohil S.; Haque, Zeba; Gupta, L. C.; Ganguli, Ashok K.

    2016-01-01

    CuFeSb is isostructural to the ferro-pnictide and chalcogenide superconductors and it is one of the few materials in the family that are known to stabilize in a ferromagnetic ground state. Majority of the members of this family are either superconductors or antiferromagnets. Therefore, CuFeSb may be used as an ideal source of spin polarized current in spin-transport devices involving pnictide and the chalcogenide superconductors. However, for that the Fermi surface of CuFeSb needs to be sufficiently spin polarized. In this paper we report direct measurement of transport spin polarization in CuFeSb by spin-resolved Andreev reflection spectroscopy. From a number of measurements using multiple superconducting tips we found that the intrinsic transport spin polarization in CuFeSb is high (∼47%). In order to understand the unique ground state of CuFeSb and the origin of large spin polarization at the Fermi level, we have evaluated the spin-polarized band structure of CuFeSb through first principles calculations. Apart from supporting the observed 47% transport spin polarization, such calculations also indicate that the Sb-Fe-Sb angles and the height of Sb from the Fe plane are strikingly different for CuFeSb than the equivalent parameters in other members of the same family thereby explaining the origin of the unique ground state of CuFeSb.

  13. High spin polarization and the origin of unique ferromagnetic ground state in CuFeSb

    Energy Technology Data Exchange (ETDEWEB)

    Sirohi, Anshu; Saha, Preetha; Gayen, Sirshendu; Gaurav, Abhishek; Jyotsna, Shubhra; Sheet, Goutam, E-mail: goutam@iisermohali.ac.in [Department of Physical Sciences, Indian Institute of Science Education and Research Mohali, Sector 81, S. A. S. Nagar, Manauli PO 140306 (India); Singh, Chandan K.; Kabir, Mukul [Department of Physics, Indian Institute of Science Education and Research, Pune 411008 (India); Thakur, Gohil S.; Haque, Zeba; Gupta, L. C. [Department of Chemistry, Indian Institute of Technology, New Delhi 110016 (India); Ganguli, Ashok K. [Department of Chemistry, Indian Institute of Technology, New Delhi 110016 (India); Institute of Nano Science & Technology, Mohali 160064 (India)

    2016-06-13

    CuFeSb is isostructural to the ferro-pnictide and chalcogenide superconductors and it is one of the few materials in the family that are known to stabilize in a ferromagnetic ground state. Majority of the members of this family are either superconductors or antiferromagnets. Therefore, CuFeSb may be used as an ideal source of spin polarized current in spin-transport devices involving pnictide and the chalcogenide superconductors. However, for that the Fermi surface of CuFeSb needs to be sufficiently spin polarized. In this paper we report direct measurement of transport spin polarization in CuFeSb by spin-resolved Andreev reflection spectroscopy. From a number of measurements using multiple superconducting tips we found that the intrinsic transport spin polarization in CuFeSb is high (∼47%). In order to understand the unique ground state of CuFeSb and the origin of large spin polarization at the Fermi level, we have evaluated the spin-polarized band structure of CuFeSb through first principles calculations. Apart from supporting the observed 47% transport spin polarization, such calculations also indicate that the Sb-Fe-Sb angles and the height of Sb from the Fe plane are strikingly different for CuFeSb than the equivalent parameters in other members of the same family thereby explaining the origin of the unique ground state of CuFeSb.

  14. Spin Torque Oscillator for High Performance Magnetic Memory

    Directory of Open Access Journals (Sweden)

    Rachid Sbiaa

    2015-06-01

    Full Text Available A study on spin transfer torque switching in a magnetic tunnel junction with perpendicular magnetic anisotropy is presented. The switching current can be strongly reduced under a spin torque oscillator (STO, and its use in addition to the conventional transport in magnetic tunnel junctions (MTJ should be considered. The reduction of the switching current from the parallel state to the antiparallel state is greater than in  the opposite direction, thus minimizing the asymmetry of the resistance versus current in the hysteresis loop. This reduction of both switching current and asymmetry under a spin torque oscillator occurs only during the writing process and does not affect the thermal stability of the free layer.

  15. Tunneling-Magnetoresistance Ratio Comparison of MgO-Based Perpendicular-Magnetic-Tunneling-Junction Spin Valve Between Top and Bottom Co2Fe6B2 Free Layer Structure.

    Science.gov (United States)

    Lee, Du-Yeong; Lee, Seung-Eun; Shim, Tae-Hun; Park, Jea-Gun

    2016-12-01

    For the perpendicular-magnetic-tunneling-junction (p-MTJ) spin valve with a nanoscale-thick bottom Co2Fe6B2 free layer ex situ annealed at 400 °C, which has been used as a common p-MTJ structure, the Pt atoms of the Pt buffer layer diffused into the MgO tunneling barrier. This transformed the MgO tunneling barrier from a body-centered cubic (b.c.c) crystallized layer into a mixture of b.c.c, face-centered cubic, and amorphous layers and rapidly decreased the tunneling-magnetoresistance (TMR) ratio. The p-MTJ spin valve with a nanoscale-thick top Co2Fe6B2 free layer could prevent the Pt atoms diffusing into the MgO tunneling barrier during ex situ annealing at 400 °C because of non-necessity of a Pt buffer layer, demonstrating the TMR ratio of ~143 %.

  16. High spin structure of nuclei near N = 50 shell gap and search for high-spin isomers using time stamped data

    International Nuclear Information System (INIS)

    Saha, S.; Palit, R.; Trivedi, T.; Sethi, J.; Joshi, P.K.; Naidu, B.S.; Donthi, R.; Jadhav, S.; Nanal, V.; Pillay, R.G.; Jain, H.C.; Kumar, S.; Biswas, D.C.; Mukherjee, G.; Saha, S.

    2011-01-01

    Information on the high-spin states of nuclei promises to provide stringent test of the interaction of the Hamiltonian used in the calculation due to smaller basis space for high J-values. It is reported in a recent shell model review that no interaction is optimized for the region of interest around N = 50 and Z = 40 shell closure. The detailed spectroscopic information of the medium and high spin states in these nuclei is required to understand the shape transition between spherical and deformed shapes at N =60 as the higher orbitals are filled. Structure of isomers near shell closure carries important information of, for example, the extent of core excitation. In the present work, the spectroscopic study of the high spin states of 89 Zr isotope have been discussed

  17. Clinical efficacy of transcatheter aortic valve replacement for severe aortic stenosis in high-risk patients: the PREVAIL JAPAN trial.

    Science.gov (United States)

    Sawa, Yoshiki; Takayama, Morimasa; Mitsudo, Kazuaki; Nanto, Shinsuke; Takanashi, Shuichiro; Komiya, Tatsuhiko; Kuratani, Toru; Tobaru, Tetsuya; Goto, Tsuyoshi

    2015-01-01

    Transcatheter aortic valve replacement (TAVR) is suggested to be less invasive and/or equally effective in comparison to conventional aortic valve replacement for high-risk symptomatic aortic stenosis patients. We herein report the initial results of a pivotal clinical trial of TAVR in Japan (the PREVAIL JAPAN). Sixty-four aortic stenosis patients (mean age 84.3 ± 6.1 years) not suitable for surgery were enrolled at three centers in Japan, with a primary composite endpoint of the 6-month post-procedure improvements in the aortic valve area and New York Heart Association (NYHA) functional classification. A transfemoral approach was used in 37 patients and a transapical approach was used in 27. The device success rate was 91.9 %. After 30 days and 6 months, the rates of mortality from any cause were 8.1 and 11.3 %, respectively. At 6 months, symptomatic stroke was found in 3.1 % of the patients, and silent infarction in 7.8 %. The aortic valve area and mean pressure gradient were significantly improved over time with both approaches (p < 0.001). At 6 months, the NYHA functional classification based on a conventional physician's assessment was improved in 87.9 % of the patients. We found results that were equivalent to those in other major TAVR trials, such as an acceptable 30-day survival (91.9 %), suggesting that balloon-expandable TAVR is effective for small Japanese AS patients classified as high-risk or inoperable.

  18. BWR reactor water cleanup system flexible wedge gate isolation valve qualification and high energy flow interruption test

    International Nuclear Information System (INIS)

    DeWall, K.G.; Steele, R. Jr.

    1989-10-01

    This report presents the results of research performed to develop technical insights for the NRC effort regarding Generic Issue 87, ''Failure of HPCI Steam Line Without Isolation.'' Volume III of this report contains the data and findings from the original research performed to assess the qualification of the valves and reported in EGG-SSRE-7387, ''Qualification of Valve Assemblies in High Energy BWR Systems Penetrating Containment.'' We present the original work here to complete the documentation trail. The recommendations contained in Volume III of this report resulted in the test program described in Volume I and II. The research began with a survey to characterize the population of normally open containment isolation valves in those process lines that connect to the primary system and penetrate containment. The qualification methodology used by the various manufacturers identified in the survey is reviewed and deficiencies in that methodology are identified. Recommendations for expanding the qualification of valve assemblies for high energy pipe break conditions are presented. 11 refs., 1 fig., 2 tabs

  19. Analysis of possibilities for a spin flip in high energy electron ring HERA

    International Nuclear Information System (INIS)

    Stres, S.; Pestotnik, R.

    2007-01-01

    In a high energy electron ring the spins of electrons become spontaneously polarized via the emission of spin-flip synchrotron radiation. By employing a radio frequency (RF) radial dipole field kicker, particle spin directions can be rotated slowly over many turns. A model which couples three dimensional spin motion and longitudinal particle motion was constructed to describe non-equilibrium spin dynamics in high energy electron storage rings. The effects of a stochastic synchrotron radiation on the orbital motion in the accelerator synchrotron plane and its influence on the spin motion are studied. The main contributions to the spin motion, the synchrotron oscillations and the stochastic synchrotron radiation, have different influence on the spin polarization reversal in different regions of the parameter space. The results indicate that polarization reversal might be obtained in high energy electron storage rings with a significant noise even with relatively small strengths of a perturbing magnetic field. The only experimental datum avaliable agrees with the model prediction, however further experimental data would be necessary to validate the model

  20. Unresolved gamma rays from high-spin states

    International Nuclear Information System (INIS)

    Stephens, F.S.

    1985-08-01

    The γ-rays which are emitted from the highest spin states in nuclei cannot be resolved using present techniques. Nevertheless, methods are being developed to study nuclear structures in this spin range. For example, coincidence data has been used in the study of superdeformations and moments of inertia. While the general properties of these correlation plots are in accord with present expectations, there are several puzzling features of the data which require more study. One unresolved aspect concerns γ-ray energy spreads in a given decay pathway. In addition, higher-order correlation methods are in various stages of inception. 15 refs., 16 figs

  1. Control Valve

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Wayne R.

    2018-03-20

    A control valve includes a first conduit having a first inlet and a first outlet and defining a first passage; a second conduit having a second inlet and a second outlet and defining a second passage, the second conduit extending into the first passage such that the second inlet is located within the first passage; and a valve plate disposed pivotably within the first passage, the valve plate defining a valve plate surface. Pivoting of the valve plate within the first passage varies flow from the first inlet to the first outlet and the valve plate is pivotal between a first position and a second position such that in the first position the valve plate substantially prevents fluid communication between the first passage and the second passage and such that in the second position the valve plate permits fluid communication between the first passage and the second passage.

  2. Investigation on Electromagnetic Models of High-Speed Solenoid Valve for Common Rail Injector

    Directory of Open Access Journals (Sweden)

    Jianhui Zhao

    2017-01-01

    Full Text Available A novel formula easily applied with high precision is proposed in this paper to fit the B-H curve of soft magnetic materials, and it is validated by comparison with predicted and experimental results. It can accurately describe the nonlinear magnetization process and magnetic saturation characteristics of soft magnetic materials. Based on the electromagnetic transient coupling principle, an electromagnetic mathematical model of a high-speed solenoid valve (HSV is developed in Fortran language that takes the saturation phenomena of the electromagnetic force into consideration. The accuracy of the model is validated by the comparison of the simulated and experimental static electromagnetic forces. Through experiment, it is concluded that the increase of the drive current is conducive to improving the electromagnetic energy conversion efficiency of the HSV at a low drive current, but it has little effect at a high drive current. Through simulation, it is discovered that the electromagnetic energy conversion characteristics of the HSV are affected by the drive current and the total reluctance, consisting of the gap reluctance and the reluctance of the iron core and armature soft magnetic materials. These two influence factors, within the scope of the different drive currents, have different contribution rates to the electromagnetic energy conversion efficiency.

  3. Nadir creatinine in posterior urethral valves: How high is low enough?

    Science.gov (United States)

    Coleman, R; King, T; Nicoara, C-D; Bader, M; McCarthy, L; Chandran, H; Parashar, K

    2015-12-01

    Large retrospective studies of people with posterior urethral valves (PUV) have reported chronic renal insufficiency (CRI) in up to one third of the participants and end-stage renal failure in up to one quarter of them. Nadir creatinine (lowest creatinine during the first year following diagnosis) is the recognised prognostic indicator for renal outcome in PUV, the most commonly used cut-off being 1 mg/dl (88.4 umol/l). To conduct a statistical analysis of nadir creatinine in PUV patients in order to identify the optimal cut-off level as a prognostic indicator for CRI. Patients treated by endoscopic valve ablation at the present institution between 1993 and 2004 were reviewed. Chronic renal insufficiency was defined as CKD2 or higher. Statistical methods included receiver operating characteristic (ROC) curve analysis, Fisher exact test and diagnostic utility tests. Statistical significance was defined as P creatinine was identified in 96 patients. The median follow-up was 9.4 (IQR 7.0, 13.4) years. A total of 29 (30.2%) patients developed CRI, with nine (9.4%) reaching end-stage renal failure. On ROC analysis, Nadir creatinine was highly prognostic for future CRI, with an Area Under the Curve of 0.887 (P creatinine >88.4 umol/l compared with 19 of 86 (22.2%) patients with lower nadir creatinine (P creatinine cut-off of 88.4 umol/l gave a specificity of 100%, but poor sensitivity of 34.5%. Lowering the cut-off to 75 umol/l resulted in improvement in all diagnostic utility tests (Table). All 14 (100%) patients with nadir creatinine >75 umol/l developed CRI, compared with 15 of 82 (18.3%) patients with lower nadir creatinine (P creatinine creatinine >75 umol/l (OR 48.988; CI 4.9-490.11) to be independent risk factors for progression to CRI. Using cut-off values of 35 umol/l and 75 umol/l, patients can be stratified into low-, intermediate- and high-risk groups, with development of CRI in 5.3%, 28.3% and 100%, respectively (P creatinine >75 umol/l (0.85

  4. Coherent spin transport through a 350 micron thick silicon wafer.

    Science.gov (United States)

    Huang, Biqin; Monsma, Douwe J; Appelbaum, Ian

    2007-10-26

    We use all-electrical methods to inject, transport, and detect spin-polarized electrons vertically through a 350-micron-thick undoped single-crystal silicon wafer. Spin precession measurements in a perpendicular magnetic field at different accelerating electric fields reveal high spin coherence with at least 13pi precession angles. The magnetic-field spacing of precession extrema are used to determine the injector-to-detector electron transit time. These transit time values are associated with output magnetocurrent changes (from in-plane spin-valve measurements), which are proportional to final spin polarization. Fitting the results to a simple exponential spin-decay model yields a conduction electron spin lifetime (T1) lower bound in silicon of over 500 ns at 60 K.

  5. High energy spin waves in iron measured by neutron scattering

    International Nuclear Information System (INIS)

    Boothroyd, A.T.; Paul, D.M.; Mook, H.A.

    1991-01-01

    We present new results for the spin were dispersion relation measured along the [ζζ0] direction in bcc iron (12% silicon) by time-of-flight, neutron inelastic scattering. The excitations were followed to the zone boundary, where they are spread over a range of energies around 300meV. 6 refs., 2 figs

  6. A study of applying variable valve timing to highly rated diesel engines

    Energy Technology Data Exchange (ETDEWEB)

    Stone, C R; Leonard, H J [comps.; Brunel Univ., Uxbridge (United Kingdom); Charlton, S J [comp.; Bath Univ. (United Kingdom)

    1992-10-01

    The main objective of the research was to use Simulation Program for Internal Combustion Engines (SPICE) to quantify the potential offered by Variable Valve Timing (VVT) in improving engine performance. A model has been constructed of a particular engine using SPICE. The model has been validated with experimental data, and it has been shown that accurate predictions are made when the valve timing is changed. (author)

  7. Valve assembly

    International Nuclear Information System (INIS)

    Sandling, M.

    1981-01-01

    An improved valve assembly, used for controlling the flow of radioactive slurry, is described. Radioactive contamination of the air during removal or replacement of the valve is prevented by sucking air from the atmosphere through a portion of the structure above the valve housing. (U.K.)

  8. High-resolution measurement of the unsteady velocity field to evaluate blood damage induced by a mechanical heart valve.

    Science.gov (United States)

    Bellofiore, Alessandro; Quinlan, Nathan J

    2011-09-01

    We investigate the potential of prosthetic heart valves to generate abnormal flow and stress patterns, which can contribute to platelet activation and lysis according to blood damage accumulation mechanisms. High-resolution velocity measurements of the unsteady flow field, obtained with a standard particle image velocimetry system and a scaled-up model valve, are used to estimate the shear stresses arising downstream of the valve, accounting for flow features at scales less than one order of magnitude larger than blood cells. Velocity data at effective spatial and temporal resolution of 60 μm and 1.75 kHz, respectively, enabled accurate extraction of Lagrangian trajectories and loading histories experienced by blood cells. Non-physiological stresses up to 10 Pa were detected, while the development of vortex flow in the wake of the valve was observed to significantly increase the exposure time, favouring platelet activation. The loading histories, combined with empirical models for blood damage, reveal that platelet activation and lysis are promoted at different stages of the heart cycle. Shear stress and blood damage estimates are shown to be sensitive to measurement resolution.

  9. Magnon Valve Effect between Two Magnetic Insulators

    Science.gov (United States)

    Wu, H.; Huang, L.; Fang, C.; Yang, B. S.; Wan, C. H.; Yu, G. Q.; Feng, J. F.; Wei, H. X.; Han, X. F.

    2018-03-01

    The key physics of the spin valve involves spin-polarized conduction electrons propagating between two magnetic layers such that the device conductance is controlled by the relative magnetization orientation of two magnetic layers. Here, we report the effect of a magnon valve which is made of two ferromagnetic insulators (YIG) separated by a nonmagnetic spacer layer (Au). When a thermal gradient is applied perpendicular to the layers, the inverse spin Hall voltage output detected by a Pt bar placed on top of the magnon valve depends on the relative orientation of the magnetization of two YIG layers, indicating the magnon current induced by the spin Seebeck effect at one layer affects the magnon current in the other layer separated by Au. We interpret the magnon valve effect by the angular momentum conversion and propagation between magnons in two YIG layers and conduction electrons in the Au layer. The temperature dependence of the magnon valve ratio shows approximately a power law, supporting the above magnon-electron spin conversion mechanism. This work opens a new class of valve structures beyond the conventional spin valves.

  10. Spin-polarized high-energy scattering of charged leptons on nucleons

    Energy Technology Data Exchange (ETDEWEB)

    Burkardt, Matthias; Nowak, Wolf-Dieter; MILLER, A.

    2009-01-01

    The proton is a composite object with spin one-half, understood to contain highly relativistic spin one-half quarks exchanging spin-one gluons, each possibly with significant orbital angular momenta. While their fundamental interactions are well described by Quantum ChromoDynamics (QCD), our standard theory of the strong interaction, nonperturbative calculations of the internal structure of the proton based directly on QCD are beginning to provide reliable results. Most of our present knowledge of the structure of the proton is based on experimental measurements interpreted within the rich framework of QCD. An area presently attracting intense interest, both experimental and theoretical, is the relationship between the spin of the proton and the spins and orbital angular momenta of its constituents. While remarkable progress has been made, especially in the last decade, the discovery and investigation of new concepts have revealed that much more remains to be learned. This progress i

  11. Large-amplitude superexchange of high-spin fermions in optical lattices

    International Nuclear Information System (INIS)

    Jürgensen, Ole; Heinze, Jannes; Lühmann, Dirk-Sören

    2013-01-01

    We show that fermionic high-spin systems with spin-changing collisions allow one to monitor superexchange processes in optical superlattices with large amplitudes and strong spin fluctuations. By investigating the non-equilibrium dynamics, we find a superexchange dominated regime at weak interactions. The underlying mechanism is driven by an emerging tunneling-energy gap in shallow few-well potentials. As a consequence, the interaction-energy gap that is expected to occur only for strong interactions in deep lattices is re-established. By tuning the optical lattice depth, a crossover between two regimes with negligible particle number fluctuations is found: firstly, the common regime with vanishing spin-fluctuations in deep lattices and, secondly, a novel regime with strong spin fluctuations in shallow lattices. We discuss the possible experimental realization with ultracold 40 K atoms and observable quantities in double wells and two-dimensional plaquettes. (paper)

  12. Generating highly polarized nuclear spins in solution using dynamic nuclear polarization

    DEFF Research Database (Denmark)

    Wolber, J.; Ellner, F.; Fridlund, B.

    2004-01-01

    A method to generate strongly polarized nuclear spins in solution has been developed, using Dynamic Nuclear Polarization (DNP) at a temperature of 1.2K, and at a field of 3.354T, corresponding to an electron spin resonance frequency of 94GHz. Trityl radicals are used to directly polarize 13C...... and other low-γ nuclei. Subsequent to the DNP process, the solid sample is dissolved rapidly with a warm solvent to create a solution of molecules with highly polarized nuclear spins. Two main applications are proposed: high-resolution liquid state NMR with enhanced sensitivity, and the use...

  13. Properties of high-spin boson interaction currents and elimination of power divergences

    International Nuclear Information System (INIS)

    Kulish, Yu.V.; Rybachuk, E.V.

    2001-01-01

    The problem of the elimination of the power divergences for the interactions of the high-spin bosons (J ≥ 1) is investigated. It is proved that in the consistent theory the high-spin boson interaction currents and the field tensors must obey similar requirements. Therefore the momentum dependencies of the propagators for all the bosons are the same. The partial differential equations derived for some components include the derivatives of order 2J for the currents. Therefore the current components for the spin-J boson must decrease with the momentum Kombi scalar p v Kombi scalar → ∞ at least as Kombi scalar p v Kombi scalar -2J

  14. Concerning moderate seniority mixing and the high spin states of some N=50 isotones

    International Nuclear Information System (INIS)

    Amusa, A.

    1987-11-01

    The high spin states of some N=50 isotones are studied in a shell model scheme involving the restriction of the valence nucleons to 2p 1/2 and 1g 9/2 orbits as well as the use of an interaction that has slight seniority non-conservation. Our results indicate that the high spin states of these nuclei, in direct contrast to their low spin states, have extra-(2p 1/2 ,1g 9/2 ) n space contributions that support violation of seniority conservation. (author). 17 refs, 2 figs, 1 tab

  15. Recent trends in high spin sensitivity magnetic resonance

    Science.gov (United States)

    Blank, Aharon; Twig, Ygal; Ishay, Yakir

    2017-07-01

    new ideas, show how these limiting factors can be mitigated to significantly improve the sensitivity of induction detection. Finally, we outline some directions for the possible applications of high-sensitivity induction detection in the field of electron spin resonance.

  16. High spin states in odd-odd {sup 132}Cs

    Energy Technology Data Exchange (ETDEWEB)

    Hayakawa, Takehito [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment; Lu, J; Furuno, K [and others

    1998-03-01

    Excited states with spin larger than 5 {Dirac_h} were newly established in the {sup 132}Cs nucleus via the {sup 124}Sn({sup 11}B,3n) reaction. Rotational bands built on the {nu}h{sub 11/2} x {pi}d{sub 5/2}, {nu}h{sub 11/2} x {pi}g{sub 7/2} and {nu}h{sub 11/2} x {pi}h{sub 11/2} configurations were observed up to spin I {approx} 16 {Dirac_h}. The {nu}h{sub 11/2} x {pi}h{sub 11/2} band shows inverted signature splitting below I < 14 {Dirac_h}. A dipole band was firstly observed in doubly odd Cs nuclei. (author)

  17. Critical emission from a high-spin black hole

    Science.gov (United States)

    Lupsasca, Alexandru; Porfyriadis, Achilleas P.; Shi, Yichen

    2018-03-01

    We consider a rapidly spinning black hole surrounded by an equatorial, geometrically thin, slowly accreting disk that is stationary and axisymmetric. We analytically compute the broadening of electromagnetic line emissions from the innermost part of the disk, which resides in the near-horizon region. The result is independent of the disk's surface emissivity and therefore universal. This is an example of critical behavior in astronomy that is potentially observable by current or future telescopes.

  18. High spin polarisation at the HERA electron storage ring

    International Nuclear Information System (INIS)

    Barber, D.P.; Boege, M.; Bremer, H.D.; Brinkmann, R.; Gianfelice-Wendt, E.; Kaiser, R.; Klanner, R.; Lewin, H.C.; Meyners, N.; Ripken, G.; Zapfe, K.; Boettcher, H.; Dueren, M.; Steffens, E.; Lomperski, M.; Rith, K.; Westphal, D.; Zetsche, F.

    1993-04-01

    This paper describes the progress made in 1992 towards increasing the vertical electron beam polarization at HERA. Utilizing harmonic spin-orbit corrections and beam tuning, the vertical polarization has been increased from 15% to nearly 60% at a beam energy of 26.7 GeV. The long-term reproducibility of the polarization is excellent. Measurements of the build-up time and the energy dependence of the polarization are also described. (orig.)

  19. Windowless microfluidic platform based on capillary burst valves for high intensity x-ray measurements

    International Nuclear Information System (INIS)

    Vig, Asger Laurberg; Enevoldsen, Nikolaj; Thilsted, Anil Haraksingh; Eriksen, Johan; Kristensen, Anders; Haldrup, Kristoffer; Feidenhans'l, Robert; Nielsen, Martin Meedom

    2009-01-01

    We propose and describe a microfluidic system for high intensity x-ray measurements. The required open access to a microfluidic channel is provided by an out-of-plane capillary burst valve (CBV). The functionality of the out-of-plane CBV is characterized with respect to the diameter of the windowless access hole, ranging from 10 to 130 μm. Maximum driving pressures from 22 to 280 mbar corresponding to refresh rates of the exposed sample from 300 Hz to 54 kHz is demonstrated. The microfluidic system is tested at beamline ID09b at the ESRF synchrotron radiation facility in Grenoble, and x-ray scattering measurements are shown to be feasible and to require only very limited amounts of sample, <1 ml/h of measurements without recapturing of sample. With small adjustments of the present chip design, scattering angles up to 30 deg. can be achieved without shadowing effects and integration on-chip mixing and spectroscopy appears straightforward.

  20. Reference book for design of valve packings, sealing high temperature water

    International Nuclear Information System (INIS)

    Doubt, G.L.

    1976-01-01

    Mockups of stuffing boxes for valves in the 1/4 to 1 in. (0.6-2.54cm) pipe size range and ASA 900 and up pressure class were tested to determine how temperature, stuffing box dimensions, packing compressive stress and stem surface finish affect water leak rate, packing friction torque and packing volume loss (creep). One brand of wire-reinforced asbestos braid on graphite-and-asbestos core packing was used in all tests. The theory of leakage through porous media was reviewed with emphasis on application to packed stuffing boxes, and a mathematical framework for relating leakage and packing friction to stuffing box dimensions and compressive stress was developed. The tests gave empirical relationships (1) for leak rate vs temperature, packing compressive stress, stem diameter and packing size, (2) for packing friction torque vs the above variables and (3) for packing creep vs temperature and stress. Packing stress affected leakage far more than any other variable, the leak rate being inversely proportional to stress to the 7.3 power at a packing temperature of 350 deg F (175 deg C). Factors which increase packing compression (density) have a strong reducing effect on leakage and a moderate to zero effect on packing friction torque. Surface finish had no visible effect on leakage, torque or creep. Empirical results and theory have been combined to show how stuffing boxes can be designed for a given leakage rate. Suggestions for decreasing leakage from existing high temperature stuffing boxes are included. (author)

  1. Topics on frustrated spin systems and high-temperature superconductors

    International Nuclear Information System (INIS)

    Lu, Yong.

    1990-01-01

    The numerical study of frustrated spin systems using the Monte Carlo simulation method and the analytic study of fluctuation phenomenon of the thermoelectric power near the superconducting transition using Green's function techniques are presented. The first frustrated system considered was the B-site antiferromagnetic (AF) spinel. Based on an Ising model, various thermodynamic and magnetic properties for both the fully frustrated structure and partially frustrated cases of a small tetragonal distortion were studied. When fully frustrated, an interesting short range order and some unusual scaling behavior were obtained. In the two tetragonally distorted cases, contracting and expanding in the crystallographic c-direction, AF long range orders and some hysteresis behavior were found. A general phase diagram was constructed as a function of the degree of the distortion. The other frustrated spin system that was studied is the magnetic phase of YBa2Cu3O(6+x). A classical spin model, was constructed, and various properties in its Ising, Heisenberg, and x-y versions were studied. The susceptibility was calculated as a function of temperature for various values of x. In the study on the thermopower fluctuation, the thermopower was determined by the linear response of the electric and heat currents to an electric field, and the linear responses were in turn calculated from correlation functions of the current

  2. High spin states in 63Cu. 17/2+ isomeric yrast state

    International Nuclear Information System (INIS)

    Tsan Ung Chan; Bruandet, J.F.; Dauchy, A.; Giorni, A.; Glasser, F.; Morand, C.; Chambon, B.; Drain, D.

    1979-01-01

    The 63 Cu nucleus has been studied via the reaction 61 Ni(α, pnγ), using different in beam γ spectroscopy techniques. An isomeric high-spin Yrast state 17/2 + (tau = 6.1 +- 0.6ns) is located at 4498 keV. The gsub(9/2) shell must be involved to explain positive high-spin states established in this work [fr

  3. Explorations on High Dimensional Landscapes: Spin Glasses and Deep Learning

    Science.gov (United States)

    Sagun, Levent

    This thesis deals with understanding the structure of high-dimensional and non-convex energy landscapes. In particular, its focus is on the optimization of two classes of functions: homogeneous polynomials and loss functions that arise in machine learning. In the first part, the notion of complexity of a smooth, real-valued function is studied through its critical points. Existing theoretical results predict that certain random functions that are defined on high dimensional domains have a narrow band of values whose pre-image contains the bulk of its critical points. This section provides empirical evidence for convergence of gradient descent to local minima whose energies are near the predicted threshold justifying the existing asymptotic theory. Moreover, it is empirically shown that a similar phenomenon may hold for deep learning loss functions. Furthermore, there is a comparative analysis of gradient descent and its stochastic version showing that in high dimensional regimes the latter is a mere speedup. The next study focuses on the halting time of an algorithm at a given stopping condition. Given an algorithm, the normalized fluctuations of the halting time follow a distribution that remains unchanged even when the input data is sampled from a new distribution. Two qualitative classes are observed: a Gumbel-like distribution that appears in Google searches, human decision times, and spin glasses and a Gaussian-like distribution that appears in conjugate gradient method, deep learning with MNIST and random input data. Following the universality phenomenon, the Hessian of the loss functions of deep learning is studied. The spectrum is seen to be composed of two parts, the bulk which is concentrated around zero, and the edges which are scattered away from zero. Empirical evidence is presented for the bulk indicating how over-parametrized the system is, and for the edges that depend on the input data. Furthermore, an algorithm is proposed such that it would

  4. Paramagnetic properties of the low- and high-spin states of yeast cytochrome c peroxidase

    International Nuclear Information System (INIS)

    Vanwetswinkel, Sophie; Nuland, Nico A. J. van; Volkov, Alexander N.

    2013-01-01

    Here we describe paramagnetic NMR analysis of the low- and high-spin forms of yeast cytochrome c peroxidase (CcP), a 34 kDa heme enzyme involved in hydroperoxide reduction in mitochondria. Starting from the assigned NMR spectra of a low-spin CN-bound CcP and using a strategy based on paramagnetic pseudocontact shifts, we have obtained backbone resonance assignments for the diamagnetic, iron-free protein and the high-spin, resting-state enzyme. The derived chemical shifts were further used to determine low- and high-spin magnetic susceptibility tensors and the zero-field splitting constant (D) for the high-spin CcP. The D value indicates that the latter contains a hexacoordinate heme species with a weak field ligand, such as water, in the axial position. Being one of the very few high-spin heme proteins analyzed in this fashion, the resting state CcP expands our knowledge of the heme coordination chemistry in biological systems

  5. Paramagnetic properties of the low- and high-spin states of yeast cytochrome c peroxidase

    Energy Technology Data Exchange (ETDEWEB)

    Vanwetswinkel, Sophie; Nuland, Nico A. J. van; Volkov, Alexander N., E-mail: ovolkov@vub.ac.be [Vrije Universiteit Brussel, Jean Jeener NMR Centre, Structural Biology Brussels (Belgium)

    2013-09-15

    Here we describe paramagnetic NMR analysis of the low- and high-spin forms of yeast cytochrome c peroxidase (CcP), a 34 kDa heme enzyme involved in hydroperoxide reduction in mitochondria. Starting from the assigned NMR spectra of a low-spin CN-bound CcP and using a strategy based on paramagnetic pseudocontact shifts, we have obtained backbone resonance assignments for the diamagnetic, iron-free protein and the high-spin, resting-state enzyme. The derived chemical shifts were further used to determine low- and high-spin magnetic susceptibility tensors and the zero-field splitting constant (D) for the high-spin CcP. The D value indicates that the latter contains a hexacoordinate heme species with a weak field ligand, such as water, in the axial position. Being one of the very few high-spin heme proteins analyzed in this fashion, the resting state CcP expands our knowledge of the heme coordination chemistry in biological systems.

  6. Combined PCI and minimally invasive heart valve surgery for high-risk patients.

    Science.gov (United States)

    Umakanthan, Ramanan; Leacche, Marzia; Petracek, Michael R; Zhao, David X; Byrne, John G

    2009-12-01

    Combined coronary artery valvular heart disease is a major cause of morbidity and mortality in the adult patient population. The standard treatment for such disease has been open heart surgery in which coronary artery bypass grafting (CABG) is performed concurrently with valve surgery using a median sternotomy and cardiopulmonary bypass. With the increasing complexity of patients referred to surgery, some patients may prove to be poor surgical candidates for combined valve and CABG surgery. In certain selected patients who fall into this category, valve surgery and percutaneous coronary intervention (PCI) have been considered a feasible alternative. Conventionally, valve surgery is performed in the cardiac surgical operating room, whereas PCI is carried out in the cardiac catheterization laboratory. Separation of these two procedural suites has presented a logistic limitation because it impedes the concomitant performance of both procedures in one setting. Hence, PCI and valve surgery usually have been performed as a "two-stage" procedure in two different operative suites, with the procedures being separated by hours, days, or weeks. Technologic advancements have made possible the construction of a "hybrid" procedural suite that combines the facilities of a cardiac surgical operating room with those of a cardiac catheterization laboratory. This design has enabled the concept of "one-stage" or "one-stop" PCI and valve surgery, allowing both procedures to be performed in a hybrid suite in one setting, separated by minutes. The advantages of such a method could prove to be multifold by enabling a less invasive surgical approach and improving logistics, patient satisfaction, and outcomes in selected patients.

  7. Multi-photon Rabi oscillations in high spin paramagnetic impurity

    International Nuclear Information System (INIS)

    Bertaina, S; Groll, N; Chen, L; Chiorescu, I

    2011-01-01

    We report on multiple photon monochromatic quantum oscillations (Rabi oscillations) observed by pulsed EPR (Electron Paramagnetic Resonance) of Mn 2+ (S = 5/2) impurities in MgO. We find that when the microwave magnetic field is similar or large than the anisotropy splitting, the Rabi oscillations have a spectrum made of many frequencies not predicted by the S = l/2 Rabi model. We show that these new frequencies come from multiple photon coherent manipulation of the multi-level spin impurity. We develop a model based on the crystal field theory and the rotating frame approximation, describing the observed phenomenon with a very good agreement.

  8. Bounds on the maximum attainable equilibrium spin polarization of protons at high energy in HERA

    International Nuclear Information System (INIS)

    Vogt, M.

    2000-12-01

    For some years HERA has been supplying longitudinally spin polarised electron and positron (e ± ) beams to the HERMES experiment and in the future longitudinal polarisation will be supplied to the II1 and ZEUS experiments. As a result there has been a development of interest in complementing the polarised e ± beams with polarised protons. In contrast to the case of e ± where spin flip due to synchrotron radiation in the main bending dipoles leads to self polarisation owing to an up-down asymmetry in the spin flip rates (Sokolov-Ternov effect), there is no convincing self polarisation mechanism for protons at high energy. Therefore protons must be polarised almost at rest in a source and then accelerated to the working energy. At HERA, if no special measures are adopted, this means that the spins must cross several thousand ''spin-orbit resonances''. Resonance crossing can lead to loss of polarisation and at high energy such effects are potentially strong since spin precession is very pronounced in the very large magnetic fields needed to contain the proton beam in HERA-p. Moreover simple models which have been successfully used to describe spin motion at low and medium energies are no longer adequate. Instead, careful numerical spin-orbit tracking simulations are needed and a new, mathematically rigorous look at the theoretical concepts is required. This thesis describes the underlying theoretical concepts, the computational tools (SPRINT) and the results of such a study. In particular strong emphasis is put on the concept of the invariant spin field and its non-perturbative construction. The invariant spin field is then used to define the amplitude dependent spin tune and to obtain numerical non-perturbative estimates of the latter. By means of these two key concepts the nature of higher order resonances in the presence of snakes is clarified and their impact on the beam polarisation is analysed. We then go on to discuss the special aspects of the HERA-p ring

  9. Shapes and alignments at high spin in some rare-earth nuclei

    International Nuclear Information System (INIS)

    Deleplanque, M.A.; Diamond, R.M.; Stephens, F.S.; Macchiavelli, A.O.; Doessing, T.; Draper, J.E.; Dines, E.L.

    1985-01-01

    The structure of nuclei at high spins is dominated by an interplay between deformation and alignment effects. Cranking models predict various shapes but at the highest spins, there is a tendency towards large triaxial deformations and sometimes towards very large prolate deformations (superdeformations). Directly involved in the shape changes are aligned orbitals which come down to the Fermi level as the nucleus rotates more rapidly. At a certain frequency, they become populated and cause large alignments. The mechanism of these changes has been explored by looking at a series of rare earth quasirotational nuclei from Dy to W in the transition region around N = 90 neutrons. The continuum spectra, corrected for incomplete population (feeding) of the high spins, are directly proportional to dynamic effective moments of inertia which describe how much spin is generated at each rotational frequency

  10. New high spin states and isomers in the {sup 208}Pb and {sup 207}Pb nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Broda, R.; Wrzesinski, J.; Pawlat, T. [and others

    1996-12-31

    The two most prominent examples of the heavy doubly closed shell (DCS) nuclei, {sup 208}Pb and {sup 132}Sn, are not accessible by conventional heavy-ion fusion processes populating high-spin states. This experimental difficulty obscured for a long time the investigation of yrast high-spin states in both DCS and neighboring nuclei and consequently restricted the study of the shell model in its most attractive regions. Recent technical development of multidetector gamma arrays opened new ways to exploit more complex nuclear processes which populate the nuclei of interest with suitable yields for gamma spectroscopy and involve population of moderately high spin states. This new possibility extended the range of accessible spin values and is a promising way to reach new yrast states. Some of these states are expected to be of high configurational purity and can be a source of important shell model parameters which possibly can be used later to check the validity of the spherical shell model description at yet higher spin and higher excitation energy. The nuclei in the closest vicinity of {sup 132}Sn are produced in spontaneous fission and states with spin values up to I=14 can be reached in fission gamma spectroscopy studies with the presently achieved sensitivity of gamma arrays. New results on yrast states in the {sup 134}Te and {sup 135}I nuclei populated in fission of the {sup 248}Cm presented at this conference illustrate such application of the resolving power offered by modern gamma techniques.

  11. Steps toward an all-electric spin valve using side-gated quantum point contacts with lateral spin–orbit coupling

    International Nuclear Information System (INIS)

    Bhandari, Nikhil; Dutta, Maitreya; Charles, James; Cahay, Marc; Newrock, Richard S; Herbert, Stephen T

    2013-01-01

    Spin-based electronics or ‘spintronics’ has been a topic of interest for over two decades. Electronic devices based on the manipulation of the electron spin are believed to offer the possibility of very small, non-volatile and ultrafast devices with very low power consumption. Since the proposal of a spin-field-effect transistor (SpinFET) by Datta and Das in 1990, many attempts have been made to achieve spin injection, detection and manipulation in semiconductor materials either by incorporating ferromagnetic materials into device architectures or by using external magnetic fields. This approach has significant design complexities, partly due to the influence of stray magnetic fields on device operation. In addition, magnetic electrodes can have magneto-resistance and spurious Hall voltages that can complicate device performance. To date, there has been no successful report of a working Datta–Das SpinFET. Over the last few years we have investigated an all-electric means of manipulating spins, one that only relies on electric fields and voltages and not on ferromagnetic materials or external magnetic fields. We believe we have found a pathway toward this goal, using in-plane side-gated quantum point contacts (QPCs) that rely on lateral spin–orbit coupling to create spin polarization. In this paper we discuss several aspects of our work, beginning with our finding what we believe is nearly complete spin-polarization in InAs QPCs by purely electrical means, our theoretical work to understand the basic mechanisms leading to that situation (asymmetric lateral confinement, lateral spin–orbit coupling and a strong e–e interaction), and our recent work extending the effort to GaAs and to dual QPC systems where one QPC acts as a polarizer and the other as an analyzer. (review)

  12. Experimental Flight Characterization of Spin Stabilized Projectiles at High Angle of Attack

    Science.gov (United States)

    2017-08-07

    impact point prediction for applications such as high-arcing, spin-stabilized munitions. 15. SUBJECT TERMS aerodynamics, spark range, spin...angles of attack increase the delivery error due to poor fire-control solutions (i.e., understanding the relationship between the gun pointing angle and...of downrange travel ) is also evident in the horizontal data. Fig. 3 Center-of-gravity motion The rolling motion is captured in Fig. 4. These

  13. The MONSTER solves nuclear structure problems at low and high spins

    International Nuclear Information System (INIS)

    Hammaren, E.; Schmid, K.W.; Gruemmer, F.

    1984-01-01

    A microscopic, particle-number and spin conserving nuclear structure model is discussed. Within a unique theory the model can describe excitation energies, moments, transitions and spectroscopic factors at low and high spins of odd-mass and doubly-even nuclei in all mass regions. With a realistic two-body Hamiltonian extracted via a G-matric description from nucleon-nucleon scattering data. The model is here applied to nuclei in the A=130 region

  14. Sutureless versus Conventional Aortic Valve Replacement: Outcomes in 70 High-Risk Patients Undergoing Concomitant Cardiac Procedures.

    Science.gov (United States)

    Hanedan, Muhammet Onur; Yuruk, Mehmet Ali; Parlar, Ali Ihsan; Ziyrek, Ugur; Arslan, Ali Kemal; Sayar, Ufuk; Mataraci, Ilker

    2018-02-01

    In elderly, high-risk surgical patients, sutureless aortic valve replacement (AVR) can often be an alternative to conventional AVR; shorter aortic cross-clamp and cardiopulmonary bypass times are the chief advantages. We compared the outcomes of sutureless AVR with those of conventional AVR in 70 elderly patients who underwent concomitant cardiac surgical procedures. We retrospectively analyzed the cases of 42 men and 28 women (mean age, 70.4 ± 10.3 yr; range, 34-93 yr) who underwent cardiac operations plus AVR with either a sutureless valve (group 1, n=38) or a conventional bioprosthetic or mechanical valve (group 2, n=32). Baseline patient characteristics were similar except for worse New York Heart Association functional status and the prevalence of diabetes mellitus in group 1. In group 1, the operative, cross-clamp, and cardiopulmonary bypass times were shorter (all P =0.001), postoperative drainage amounts were lower ( P =0.009), hospital stays were shorter ( P =0.004), and less red blood cell transfusion was needed ( P =0.037). Echocardiograms before patients' discharge from the hospital showed lower peak and mean aortic gradients in group 1 (mean transvalvular gradient, 8.4 ± 2.8 vs 12.2 ± 5.2 mmHg; P =0.012). We found that elderly, high-risk patients who underwent multiple cardiac surgical procedures and sutureless AVR had better hemodynamic outcomes and shorter ischemic times than did patients who underwent conventional AVR.

  15. High-spin, multiparticle isomers in 121,123Sb

    International Nuclear Information System (INIS)

    Jones, G. A.; Walker, P. M.; Podolyak, Zs.; Cullen, I. J.; Garnsworthy, A. B.; Liu, Z.; Thompson, N. J.; Williams, S. J.; Zhu, S.; Carpenter, M. P.; Janssens, R. V. F.; Khoo, T. L.; Seweryniak, D.; Carroll, J. J.; Chakrawarthy, R. S.; Hackman, G.; Chowdhury, P.; Dracoulis, G. D.; Lane, G. J.; Kondev, F. G.

    2008-01-01

    Isomers in near-spherical Z=51, antimony isotopes are reported here for the first time using fusion-fission reactions between 27 Al and a pulsed 178 Hf beam of energy, 1150 MeV. γ rays were observed from the decay of isomeric states with half-lives, T 1/2 =200(30) and 52(3)μs, and angular momenta I=((25/2)) and I π =(23/2) + , in 121,123 Sb, respectively. These states are proposed to correspond to ν(h (11/2) ) 2 configurations, coupled to an odd d (5/2) or g (7/2) proton. Nanosecond isomers were also identified at I π =(19/2) - [T 1/2 =8.5(5) ns] in 121 Sb and I π =((15/2) - ) [T 1/2 =37(4) ns] in 123 Sb. Information on spins and parities of states in these nuclei was obtained using a combination of angular correlation and intensity-balance measurements. The configurations of states in these nuclei are discussed using a combination of spin/energy systematics and shell-model calculations for neighboring tin isotones and antimony isotopes

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-08-01

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

  17. VALVE TURBO-ALTERNATOR AS ADDITIONAL HYBRID CAR DEVICE FOR THE HIGH-VOLTAGE BATTERY CHARGE

    Directory of Open Access Journals (Sweden)

    S. Kolesnikov

    2009-01-01

    Full Text Available The description of the hybrid car, its drive components and method of the solution of the problem with moving period of the car on electric pulling by means of valve turbo-alternator is given in this article.

  18. Butterfly valve with metal seals controls flow of hydrogen from cryogenic through high temperatures

    Science.gov (United States)

    Johnson, L. D.

    1967-01-01

    Butterfly valve with metal seals operates over a temperature range of minus 423 degrees to plus 440 degrees F with hydrogen as a medium and in a radiation environment. Media flow is controlled by an internal butterfly disk which is rotated by an actuation shaft.

  19. Transcatheter aortic valve prosthesis surgically replaced 4 months after implantation

    DEFF Research Database (Denmark)

    Thyregod, Hans Gustav; Lund, Jens Teglgaard; Engstrøm, Thomas

    2010-01-01

    Transcatheter aortic valve implantation is a new and rapidly evolving treatment option for high-risk surgical patients with degenerative aortic valve stenosis. Long-term results with these new valve prostheses are lacking, and potential valve dysfunction and failure would require valve replacemen....... We report the first case of surgical valve replacement in a patient with a dysfunctional transcatheter-implanted aortic valve prosthesis 4 months after implantation....

  20. New results on spin determination of nanosatellite BLITS from High Repetition Rate SLR data

    Science.gov (United States)

    Kucharski, D.; Kirchner, G.; Lim, H.-C.; Koidl, F.

    2013-03-01

    The nanosatellite BLITS (Ball Lens In The Space) demonstrates a successful design of the new spherical lens type satellite for Satellite Laser Ranging (SLR). The spin parameters of the satellite were calculated from more than 1000 days of SLR data collected from 6 High Repetition Rate (HRR) systems: Beijing, Changchun, Graz, Herstmonceux, Potsdam, Shanghai.Analysis of the 892 passes (September 26, 2009-June 18, 2012) shows precession of the spin axis around orientation of the along track vector calculated at the launch epoch of the satellite RA = 9h16m39s, Dec = 43.1°. The spin period of BLITS remains stable with the mean value Tmean = 5.613 s, RMS = 11 ms. The incident angle between the spin axis and the symmetry axis of the body changes within 60° range.

  1. Design and performance of a spin-polarized electron energy loss spectrometer with high momentum resolution

    Energy Technology Data Exchange (ETDEWEB)

    Vasilyev, D.; Kirschner, J. [Max-Planck-Institut für Mikrostrukturphysik, Weinberg 2, 06120 Halle (Germany)

    2016-08-15

    We describe a new “complete” spin-polarized electron energy loss spectrometer comprising a spin-polarized primary electron source, an imaging electron analyzer, and a spin analyzer of the “spin-polarizing mirror” type. Unlike previous instruments, we have a high momentum resolution of less than 0.04 Å{sup −1}, at an energy resolution of 90-130 meV. Unlike all previous studies which reported rather broad featureless data in both energy and angle dependence, we find richly structured spectra depending sensitively on small changes of the primary energy, the kinetic energy after scattering, and of the angle of incidence. The key factor is the momentum resolution.

  2. High spin levels populated in multinucleon transfer reaction with 480 MeV 12C

    International Nuclear Information System (INIS)

    Kraus, L.; Boucenna, A.; Linck, I.

    1988-01-01

    Two- and three-nucleon stripping reactions induced by 480 MeV 12 C have been studied on 12 C, 16 O, 28 Si, 40 Ca and 54 Fe target nuclei. Discrete levels are fed with cross sections up to 1 mb/sr for d-transfer reactions and one order and two orders of magnitude less for 2p- and 3 He-transfer reactions, respectively. These reactions preferentially populate high spin states with stretched configurations. Several spin assignments were known from transfer reactions induced by lighter projectiles at incident energies well above the Coulomb barrier. In the case of two-nucleon transfer reactions, the energy of these states is well reproduced by crude shell model calculations. Such estimates are of use in proposing spins of newly observed states especially as the shapes of the measured angular distributions are independent of the final spin of the residual nucleus

  3. A high-field adiabatic fast passage ultracold neutron spin flipper for the UCNA experiment

    Energy Technology Data Exchange (ETDEWEB)

    Holley, A. T.; Pattie, R. W.; Young, A. R. [Department of Physics, North Carolina State University, Raleigh, North Carolina 27695 (United States); Broussard, L. J. [Department of Physics, Duke University, Durham, North Carolina 27708 (United States); Davis, J. L.; Ito, T. M.; Lyles, J. T. M.; Makela, M.; Morris, C. L.; Mortensen, R.; Saunders, A. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Hickerson, K.; Mendenhall, M. P. [W. K. Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, California 91125 (United States); Liu, C.-Y. [Department of Physics, Indiana University, Bloomington, Indiana 47405 (United States); Mammei, R. R. [Department of Physics, Virginia Tech, Blacksburg, Virginia 24061 (United States); Rios, R. [Department of Physics, Idaho State University, Pocatello, Idaho 83209 (United States)

    2012-07-15

    The UCNA collaboration is making a precision measurement of the {beta} asymmetry (A) in free neutron decay using polarized ultracold neutrons (UCN). A critical component of this experiment is an adiabatic fast passage neutron spin flipper capable of efficient operation in ambient magnetic fields on the order of 1 T. The requirement that it operate in a high field necessitated the construction of a free neutron spin flipper based, for the first time, on a birdcage resonator. The design, construction, and initial testing of this spin flipper prior to its use in the first measurement of A with UCN during the 2007 run cycle of the Los Alamos Neutron Science Center's 800 MeV proton accelerator is detailed. These studies determined the flipping efficiency of the device, averaged over the UCN spectrum present at the location of the spin flipper, to be {epsilon}=0.9985(4).

  4. High-order moments of spin-orbit energy in a multielectron configuration

    Science.gov (United States)

    Na, Xieyu; Poirier, M.

    2016-07-01

    In order to analyze the energy-level distribution in complex ions such as those found in warm dense plasmas, this paper provides values for high-order moments of the spin-orbit energy in a multielectron configuration. Using second-quantization results and standard angular algebra or fully analytical expressions, explicit values are given for moments up to 10th order for the spin-orbit energy. Two analytical methods are proposed, using the uncoupled or coupled orbital and spin angular momenta. The case of multiple open subshells is considered with the help of cumulants. The proposed expressions for spin-orbit energy moments are compared to numerical computations from Cowan's code and agree with them. The convergence of the Gram-Charlier expansion involving these spin-orbit moments is analyzed. While a spectrum with infinitely thin components cannot be adequately represented by such an expansion, a suitable convolution procedure ensures the convergence of the Gram-Charlier series provided high-order terms are accounted for. A corrected analytical formula for the third-order moment involving both spin-orbit and electron-electron interactions turns out to be in fair agreement with Cowan's numerical computations.

  5. Transcatheter Mitral Valve-in-Ring Implantation

    LENUS (Irish Health Repository)

    Tanner, RE

    2018-05-01

    Failed surgical mitral valve repair using an annuloplasty ring has traditionally been treated with surgical valve replacement or repair1. For patients at high risk for repeat open heart surgery, placement of a trans-catheter aortic valve (i.e., TAVI valve) within the mitral ring (i.e., Mitral-Valve-in-Ring, MViR) has emerged as a novel alternative treatment strategy2-5 . We describe our experience of a failed mitral valve repair that was successfully treated with a TAVI valve delivered via the trans-septal approach, and summarise the data relating to this emerging treatment strategy.

  6. Devices and process for high-pressure magic angle spinning nuclear magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Hoyt, David W.; Sears, Jesse A.; Turcu, Romulus V. F.; Rosso, Kevin M.; Hu, Jian Zhi

    2017-12-05

    A high-pressure magic angle spinning (MAS) rotor is detailed that includes a high-pressure sample cell that maintains high pressures exceeding 150 bar. The sample cell design minimizes pressure losses due to penetration over an extended period of time.

  7. Devices and process for high-pressure magic angle spinning nuclear magnetic resonance

    Science.gov (United States)

    Hoyt, David W; Sears, Jr., Jesse A; Turcu, Romulus V.F.; Rosso, Kevin M; Hu, Jian Zhi

    2014-04-08

    A high-pressure magic angle spinning (MAS) rotor is detailed that includes a high-pressure sample cell that maintains high pressures exceeding 150 bar. The sample cell design minimizes pressure losses due to penetration over an extended period of time.

  8. Mitral Valve Disease

    Science.gov (United States)

    ... for mitral valve replacement—mechanical valves (metal) or biological valves (tissue). The principal advantage of mechanical valves ... small risk of stroke due to blood clotting. Biological valves usually are made from animal tissue. Biological ...

  9. A High-Spin Rate Measurement Method for Projectiles Using a Magnetoresistive Sensor Based on Time-Frequency Domain Analysis.

    Science.gov (United States)

    Shang, Jianyu; Deng, Zhihong; Fu, Mengyin; Wang, Shunting

    2016-06-16

    Traditional artillery guidance can significantly improve the attack accuracy and overall combat efficiency of projectiles, which makes it more adaptable to the information warfare of the future. Obviously, the accurate measurement of artillery spin rate, which has long been regarded as a daunting task, is the basis of precise guidance and control. Magnetoresistive (MR) sensors can be applied to spin rate measurement, especially in the high-spin and high-g projectile launch environment. In this paper, based on the theory of a MR sensor measuring spin rate, the mathematical relationship model between the frequency of MR sensor output and projectile spin rate was established through a fundamental derivation. By analyzing the characteristics of MR sensor output whose frequency varies with time, this paper proposed the Chirp z-Transform (CZT) time-frequency (TF) domain analysis method based on the rolling window of a Blackman window function (BCZT) which can accurately extract the projectile spin rate. To put it into practice, BCZT was applied to measure the spin rate of 155 mm artillery projectile. After extracting the spin rate, the impact that launch rotational angular velocity and aspect angle have on the extraction accuracy of the spin rate was analyzed. Simulation results show that the BCZT TF domain analysis method can effectively and accurately measure the projectile spin rate, especially in a high-spin and high-g projectile launch environment.

  10. Spin dynamics on cyclic iron wheels in high magnetic fields

    International Nuclear Information System (INIS)

    Schnelzer, Lars

    2008-01-01

    In the present thesis the spin dynamics of cyclic spin-cluster compounds, the so called ''ferric wheels'' were studied by means of the NMR. In the iron wheels Li/Na rate at Fe 6 (tea) 6 and Cs rate at Fe 8 (tea) 8 as probes of NMR both the protons and the centrally lying alkali atoms 7 Li, 23 Na, and 133 Cs were available. For this purpose measurements in the magnetic field region up to B=20 T and at temperatures between room temperature and T=50 mK were performed. The longitudinal relaxation rate was temperature dependently studied at two field values on the lithium cluster and a frequency independent maximum of the relaxation rate at a temperature of T∼30 K resulted. Different behaviour showed the measurement on the sodium cluster. the longitudinal relaxation rate slopes linearly with the temperature and shows no maximum. The two quadrupole satellites of the 23 Na could be resolved. From the distance of the satellites to the central transition both on the field gradient of the iron ring and on the orientation of the symmetry axis to the external magnetic field could be concluded. The determined field gradient of the Na rate at Fe 6 (tea) 6 of eq=4.78(11).10 20 V/m 2 was in very good agreement with the present theoretically calculated value. The orientation of the crystal was determined to θ(c,B)=62.8 . The very low splitting of the 7 Li NMR spectrum of the lithium cluster allows to give as upper limit for the value of the field gradient eq=1.82(11).10 20 V/m 2 . From the seven lines of the cesium spectrum theoretically to be expected five were resolved. The evaluation yielded for the cesium ring a value of eq=-1.3(1).10 21 V/m 2 . The study of the field-dependent line position of the 23 Na NMR line led to the determination of the parameter of the transferred hyperfine interaction to A tHf /2π=140 kHz. For the first time on a cyclic iron cluster a level crossing could be studied by means of the central ion. The temperature dependence of the longitudinal

  11. Spectroscopy of high-spin states of 206Po

    International Nuclear Information System (INIS)

    Baxter, A.M.; Byrne, A.P.; Dracoulis, G.D.; Bark, R.A.; Riess, F.; Stuchbery, A.E.; Kruse, M.C.; Poletti, A.R.

    1990-05-01

    The yrast and near-yrast energy levels of 206 Po have been investigated to over 9 MeV excitation and up to spins with J=24. The measure-ments consisted of γ-γ coincidence data, internal-conversion-electron spectra, time spectra of γ-rays relative to a pulsed beam, excitation functions and γ-ray angular distributions. Two new isomers, with lifetime in the one-nonasecond range,were found. The observed structure is compared with the predictions of empirical shell-model calculations in which 206 Po is regarded as a 208 Pb core with two valence protons and four valence neutron holes. The agreement is generaly satisfactory for the observed odd-parity levels and for even parity levels with J > 12; those with J = 6 to 12 are better accounted for by weak coupling of two valence protons to a 204 Pb core in its 0 + 1, 2 + 1 and 4 + 1 states. 33 refs., 7 tabs., 12 figs

  12. High-fidelity gates in quantum dot spin qubits.

    Science.gov (United States)

    Koh, Teck Seng; Coppersmith, S N; Friesen, Mark

    2013-12-03

    Several logical qubits and quantum gates have been proposed for semiconductor quantum dots controlled by voltages applied to top gates. The different schemes can be difficult to compare meaningfully. Here we develop a theoretical framework to evaluate disparate qubit-gating schemes on an equal footing. We apply the procedure to two types of double-dot qubits: the singlet-triplet and the semiconducting quantum dot hybrid qubit. We investigate three quantum gates that flip the qubit state: a DC pulsed gate, an AC gate based on logical qubit resonance, and a gate-like process known as stimulated Raman adiabatic passage. These gates are all mediated by an exchange interaction that is controlled experimentally using the interdot tunnel coupling g and the detuning [Symbol: see text], which sets the energy difference between the dots. Our procedure has two steps. First, we optimize the gate fidelity (f) for fixed g as a function of the other control parameters; this yields an f(opt)(g) that is universal for different types of gates. Next, we identify physical constraints on the control parameters; this yields an upper bound f(max) that is specific to the qubit-gate combination. We show that similar gate fidelities (~99:5%) should be attainable for singlet-triplet qubits in isotopically purified Si, and for hybrid qubits in natural Si. Considerably lower fidelities are obtained for GaAs devices, due to the fluctuating magnetic fields ΔB produced by nuclear spins.

  13. Post-Newtonian Dynamics in Dense Star Clusters: Highly Eccentric, Highly Spinning, and Repeated Binary Black Hole Mergers.

    Science.gov (United States)

    Rodriguez, Carl L; Amaro-Seoane, Pau; Chatterjee, Sourav; Rasio, Frederic A

    2018-04-13

    We present models of realistic globular clusters with post-Newtonian dynamics for black holes. By modeling the relativistic accelerations and gravitational-wave emission in isolated binaries and during three- and four-body encounters, we find that nearly half of all binary black hole mergers occur inside the cluster, with about 10% of those mergers entering the LIGO/Virgo band with eccentricities greater than 0.1. In-cluster mergers lead to the birth of a second generation of black holes with larger masses and high spins, which, depending on the black hole natal spins, can sometimes be retained in the cluster and merge again. As a result, globular clusters can produce merging binaries with detectable spins regardless of the birth spins of black holes formed from massive stars. These second-generation black holes would also populate any upper mass gap created by pair-instability supernovae.

  14. Post-Newtonian Dynamics in Dense Star Clusters: Highly Eccentric, Highly Spinning, and Repeated Binary Black Hole Mergers

    Science.gov (United States)

    Rodriguez, Carl L.; Amaro-Seoane, Pau; Chatterjee, Sourav; Rasio, Frederic A.

    2018-04-01

    We present models of realistic globular clusters with post-Newtonian dynamics for black holes. By modeling the relativistic accelerations and gravitational-wave emission in isolated binaries and during three- and four-body encounters, we find that nearly half of all binary black hole mergers occur inside the cluster, with about 10% of those mergers entering the LIGO/Virgo band with eccentricities greater than 0.1. In-cluster mergers lead to the birth of a second generation of black holes with larger masses and high spins, which, depending on the black hole natal spins, can sometimes be retained in the cluster and merge again. As a result, globular clusters can produce merging binaries with detectable spins regardless of the birth spins of black holes formed from massive stars. These second-generation black holes would also populate any upper mass gap created by pair-instability supernovae.

  15. Fracturing mechanics before valve-in-valve therapy of small aortic bioprosthetic heart valves.

    Science.gov (United States)

    Johansen, Peter; Engholt, Henrik; Tang, Mariann; Nybo, Rasmus F; Rasmussen, Per D; Nielsen-Kudsk, Jens Erik

    2017-10-13

    Patients with degraded bioprosthetic heart valves (BHV) who are not candidates for valve replacement may benefit from transcatheter valve-in-valve (VIV) therapy. However, in smaller-sized surgical BHV the resultant orifice may become too narrow. To overcome this, the valve frame can be fractured by a high-pressure balloon prior to VIV. However, knowledge on fracture pressures and mechanics are prerequisites. The aim of this study was to identify the fracture pressures needed in BHV, and to describe the fracture mechanics. Commonly used BHV of small sizes were mounted on a high-pressure balloon situated in a biplane fluoroscopic system with a high-speed camera. The instant of fracture was captured along with the balloon pressure. The valves were inspected for material protrusion and later dissected for fracture zone investigation and description. The valves with a polymer frame fractured at a lower pressure (8-10 atm) than those with a metal stent (19-26 atm). None of the fractured valves had elements protruding. VIV procedures in small-sized BHV may be performed after prior fracture of the valve frame by high-pressure balloon dilatation. This study provides tentative guidelines for expected balloon sizes and pressures for valve fracturing.

  16. High spin levels in 62Zn, 64Zn, 66Zn, and 68Zn

    International Nuclear Information System (INIS)

    Bruandet, J.-F.

    1976-01-01

    Investigation by in-beam gamma spectroscopy of high-spin states in the even zinc isotopes has been made using the Ni(α,2nγ)Zn reactions at Esub(α) approximately equal to 30MeV for 62 Zn, 64 Zn and 66 Zn, and the 65 Cu(α,pγ) reaction at Esub(α) approximately equal to 18MeV for 68 Zn. The high-spin states feeding by varying the incident particles: p, 3 He,α, 12 C is discussed. It is pointed out that the gsub(9/2) orbital plays an important role in the structure of the high-spin states. The variation of the inertia momentum throughout the yrast line shows a backbending behavior and a shape transition associated to the occurence, for J>6, of rotational states is speculated [fr

  17. High-resolution subject-specific mitral valve imaging and modeling: experimental and computational methods.

    Science.gov (United States)

    Toma, Milan; Bloodworth, Charles H; Einstein, Daniel R; Pierce, Eric L; Cochran, Richard P; Yoganathan, Ajit P; Kunzelman, Karyn S

    2016-12-01

    The diversity of mitral valve (MV) geometries and multitude of surgical options for correction of MV diseases necessitates the use of computational modeling. Numerical simulations of the MV would allow surgeons and engineers to evaluate repairs, devices, procedures, and concepts before performing them and before moving on to more costly testing modalities. Constructing, tuning, and validating these models rely upon extensive in vitro characterization of valve structure, function, and response to change due to diseases. Micro-computed tomography ([Formula: see text]CT) allows for unmatched spatial resolution for soft tissue imaging. However, it is still technically challenging to obtain an accurate geometry of the diastolic MV. We discuss here the development of a novel technique for treating MV specimens with glutaraldehyde fixative in order to minimize geometric distortions in preparation for [Formula: see text]CT scanning. The technique provides a resulting MV geometry which is significantly more detailed in chordal structure, accurate in leaflet shape, and closer to its physiological diastolic geometry. In this paper, computational fluid-structure interaction (FSI) simulations are used to show the importance of more detailed subject-specific MV geometry with 3D chordal structure to simulate a proper closure validated against [Formula: see text]CT images of the closed valve. Two computational models, before and after use of the aforementioned technique, are used to simulate closure of the MV.

  18. Transcatheter aortic valve prosthesis surgically replaced 4 months after implantation

    DEFF Research Database (Denmark)

    Thyregod, Hans Gustav; Lund, Jens Teglgaard; Engstrøm, Thomas

    2010-01-01

    Transcatheter aortic valve implantation is a new and rapidly evolving treatment option for high-risk surgical patients with degenerative aortic valve stenosis. Long-term results with these new valve prostheses are lacking, and potential valve dysfunction and failure would require valve replacemen...

  19. Femtosecond time-resolved optical and Raman spectroscopy of photoinduced spin crossover: temporal resolution of low-to-high spin optical switching.

    Science.gov (United States)

    Smeigh, Amanda L; Creelman, Mark; Mathies, Richard A; McCusker, James K

    2008-10-29

    A combination of femtosecond electronic absorption and stimulated Raman spectroscopies has been employed to determine the kinetics associated with low-spin to high-spin conversion following charge-transfer excitation of a FeII spin-crossover system in solution. A time constant of tau = 190 +/- 50 fs for the formation of the 5T2 ligand-field state was assigned based on the establishment of two isosbestic points in the ultraviolet in conjunction with changes in ligand stretching frequencies and Raman scattering amplitudes; additional dynamics observed in both the electronic and vibrational spectra further indicate that vibrational relaxation in the high-spin state occurs with a time constant of ca. 10 ps. The results set an important precedent for extremely rapid, formally forbidden (DeltaS = 2) nonradiative relaxation as well as defining the time scale for intramolecular optical switching between two electronic states possessing vastly different spectroscopic, geometric, and magnetic properties.

  20. Standard Practice for Installation, Inspection, and Maintenance of Valve-body Pressure-relief Methods for Geothermal and Other High-Temperature Liquid Applications

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2003-01-01

    1.1 This practice covers installation, inspection, and maintenance of valve body cavity pressure relief methods for valves used in geothermal and other high-temperature liquid service. The valve type covered by this practice is a design with an isolated body cavity such that when the valve is in either the open or closed position pressure is trapped in the isolated cavity, and there is no provision to relieve the excess pressure internally. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

  1. Observation of a new high-spin isomer in 94Pd

    International Nuclear Information System (INIS)

    Brock, T. S.; Nara Singh, B. S.; Wadsworth, R.; Boutachkov, P.; Gorska, M.; Grawe, H.; Pietri, S.; Domingo-Pardo, C.; Caceres, L.; Engert, T.; Farinon, F.; Gerl, J.; Goel, N.; Kojuharov, I.; Kurz, N.; Nociforo, C.; Prochazka, A.; Schaffner, H.; Weick, H.; Braun, N.

    2010-01-01

    A second γ-decaying high-spin isomeric state, with a half-life of 197(22)ns, has been identified in the N=Z+2 nuclide 94 Pd as part of a stopped-beam Rare Isotope Spectroscopic INvestigation at GSI (RISING) experiment. Weisskopf estimates were used to establish a tentative spin/parity of 19 - , corresponding to the maximum possible spin of a negative parity state in the restricted (p 1/2 , g 9/2 ) model space of empirical shell model calculations. The reproduction of the E3 decay properties of the isomer required an extension of the model space to include the f 5/2 and p 3/2 orbitals using the CD-Bonn potential. This is the first time that such an extension has been required for a high-spin isomer in the vicinity of 100 Sn and reveals the importance of such orbits for understanding the decay properties of high-spin isomers in this region. However, despite the need for the extended model space for the E3 decay, the dominant configuration for the 19 - state remains (πp 1/2 -1 g 9/2 -3 ) 11 x (νg 9/2 -2 ) 8 . The half-life of the known, 14 + , isomer was remeasured and yielded a value of 499(13) ns.

  2. A high field optical-pumping spin-exchange polarized deuterium source

    International Nuclear Information System (INIS)

    Coulter, K.P.; Holt, R.J.; Kinney, E.R.; Kowalczyk, R.S.; Poelker, M.; Potterveld, D.H.; Young, L.; Zeidman, B.; Toporkov, D.

    1992-01-01

    Recent results from a prototype high field optical-pumping spin-exchange polarized deuterium source are presented. Atomic polarization as high as 62% have been observed with an intensity of 6.3 x 10 17 atoms-sec -1 and 65% dissociation fraction

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

    International Nuclear Information System (INIS)

    Wang, Xin

    1996-12-01

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

  4. Superdeformed and high-spin nuclear structure data on the INTERNET

    International Nuclear Information System (INIS)

    Singh, B.; Firestone, R.B.; Chu, S.Y.F.

    1997-01-01

    With the advent of the large detector arrays GAMMASPHERE, EUROGAM, and GASP, a wealth of new information about the properties of nuclei at high spin has become available. Superdeformed and high-spin nuclear structure data and associated bibliographic information made available on INTERNET by the Isotopes Project at LBNL are described. The Table of Superdeformed Bands and Fission Isomers on the INTERNET will be updated continuously, and new recent reference lists will be provided approximately every three months. This information will also be published annually in the Table of Isotopes CD-ROM updates. (author)

  5. The high-spin structure of 158Er - a theoretical study

    International Nuclear Information System (INIS)

    Bengtsson, Tord.

    1990-01-01

    To demonstrate the use of diabatic orbitals in high-spin calculations, the yrast structure of 158 Er is calculated and compared to experiment. A very satisfactory reproduction of the observed spectra is obtained form lowest spins through the collective bands up to band terminations. From results like this, a detailed understanding of the observed features emerge. In this case for example, the different alignment properties in negative parity bands can be understood as due to deformation differences and the existence of additional bands are predicted. Furthermore, the limitations of the cranked mean field approach can be investigated due to the high level of detail in this approach. (author)

  6. Effect of high-frequency excitation on natural frequencies of spinning discs

    DEFF Research Database (Denmark)

    Hansen, Morten Hartvig

    2000-01-01

    The effect of high-frequency, non-resonant parametric excitation on the low-frequency response of spinning discs is considered. The parametric excitation is obtained through a non-constant rotation speed, where the frequency of the pulsating overlay is much higher than the lowest natural frequenc......The effect of high-frequency, non-resonant parametric excitation on the low-frequency response of spinning discs is considered. The parametric excitation is obtained through a non-constant rotation speed, where the frequency of the pulsating overlay is much higher than the lowest natural...

  7. Structure of high-spin isomers in trans-lead nuclei

    International Nuclear Information System (INIS)

    Dracoulis, G.D.

    1990-01-01

    The structure of core-excited high-spin isomers in the N ≤ 126 isotopes of At, Rn and Fr is reviewed. New results for high-spin states in 211 Rn and 212 Rn, approaching the limit of the available angular momentum from the valence particles, are presented. The recurring experimental feature is decay by very enhanced E3 transitions. These, and other properties are explained in a natural way by inclusion of particle-octupole vibration coupling, in a semi-empirical shell model. The deformed independent particle model is not successful in explaining these features. 40 refs., 4 tabs., 11 figs

  8. IBFA description of high-spin positive-parity states in Rh isotopes

    International Nuclear Information System (INIS)

    Bucurescu, D.; Cata, G.; Cutoiu, D.; Constantinescu, G.; Ivascu, M.; Zamfir, N.V.

    1985-01-01

    Properties of the odd-mass Rh isotopes are investigated in the framework of the interacting boson-fermion approximation (IBFA) model in which the odd proton moves in the 1gsub(9/2) and 2dsub(5/2) orbitals. Lifetimes of some high-spin positive-parity states in 99 Rh obtained by the recoil-distance method with the 88 Sr( 14 N,3n) reaction are also reported. Calculated excitation energies and electromagnetic properties of the high-spin positive-parity states are compared with experiment and an acceptable agreement is obtained. (orig.)

  9. High-pressure balloon valvuloplasty for severe pulmonary valve stenosis: a prospective observational pilot study in 25 dogs.

    Science.gov (United States)

    Belanger, Catherine; Gunther-Harrington, Catherine T; Nishimura, Satoko; Oldach, Maureen S; Fousse, Samantha L; Visser, Lance C; Stern, Joshua A

    2018-04-01

    We aimed to evaluate safety and efficacy of high-pressure balloon valvuloplasty (HPBVP) for treatment of canine severe pulmonary valve stenosis (PS). A secondary aim was to provide pre-procedure predictors of success. Twenty-five dogs. Prospective observational study. Dogs with severe PS (echocardiographically derived trans-pulmonary peak/maximum pressure gradient (EDPG) ≥80 mmHg) were recruited. All dogs underwent echocardiography before and 20-24hrs after HPBVP using a high-pressure balloon with rated burst pressures ranging from 12 to 18 ATM. Procedural success was defined as a post-HPBVP EDPG reduction of ≥50% or reduction into at least the moderate category of PS (50-79 mmHg). Optimal result was defined as a post-procedural EDPG ≤30 mmHg. Initial median (IQR) EDPG for all dogs was 96 (88, 127) mmHg with a post-operative median of 48 (36, 65) mmHg. The median EDPG reduction provided by HPBVP was 63% (39, 68); procedural success rate was 92% (23 dogs). Optimal results were achieved in 56% (14 dogs). There were no significant correlations between EDPG reduction and valve morphology (Type A and Type B) or severity of right ventricular hypertrophy. Pulmonary valve annulus diameter was the only echocardiographic variable that was significantly correlated to EDPG reduction (p = 0.02; r = -0.46). No dog experienced any anesthetic or surgical complications, and all patients survived the procedure. In this cohort of 25 dogs with severe PS, HPBVP was safe and effective. The procedural success rate and high number of optimal results achieved with HPBVP suggest future randomized controlled trials comparing HPBVP to conventional valvuloplasty are warranted. Copyright © 2018 Elsevier B.V. All rights reserved.

  10. Design and sealing requirements for valves in the high-temperature field. Konstruktions- und Abdichtungsanforderungen fuer Armaturen im Hochtemperaturbereich

    Energy Technology Data Exchange (ETDEWEB)

    Hacker, H [Hamburgische Electricitaets-Werke AG, Hamburg (Germany); Traeger, K [Babcock Sempell AG, Oberhausen (Germany)

    1994-10-01

    In the combustion of fossil fuels, the reduction of the CO[sub 2] discharge can only be achieved by increasing efficiency. The drive for greater economy and higher efficiencies is leading to the development of high heat-resistant steels (for example P 9 1), which permit higher operating pressures and steam temperatures. In this way, an increase in efficiency is possible without thereby losing sight of economy. This paper describes the main technical and design consequences which result from increased pressures and steam temperatures for the valve manufacturers. (orig.)

  11. High-spin levels in 39K excited by the 41Ca(d,α) reaction

    International Nuclear Information System (INIS)

    Sugarbaker, E.; Boyd, R.N.; Cline, D.; Vold, P.B.; Lien, J.R.; Goode, P.R.

    1979-01-01

    The 41 Ca(d,α) 39 K reaction has been used to investigate the low-lying high-spin states in 39 K. Conflicting spin assignments for the 5.719 MeV level in 39 K of 9/2 - of 13/2 - have been suggested in earlier studies. A 1p-2h model reproduces both the 41 Ca(d,α) 39 K and 39 K(α,α') 39 K reaction data leading to the high-spin states if the 5.719 MeV level is assumed to have a J/sup π/ of 13/2 - . An alternate assignment of J/sup π/ = 9/2 - for this level is shown to produce very poor agreement with the model predictions

  12. EFFECTS OF SPIN ON HIGH-ENERGY RADIATION FROM ACCRETING BLACK HOLES

    Energy Technology Data Exchange (ETDEWEB)

    O’ Riordan, Michael; Pe’er, Asaf [Physics Department, University College Cork, Cork (Ireland); McKinney, Jonathan C., E-mail: michael_oriordan@umail.ucc.ie [Department of Physics and Joint Space-Science Institute, University of Maryland, College Park, MD 20742 (United States)

    2016-11-01

    Observations of jets in X-ray binaries show a correlation between radio power and black hole spin. This correlation, if confirmed, points toward the idea that relativistic jets may be powered by the rotational energy of black holes. In order to examine this further, we perform general relativistic radiative transport calculations on magnetically arrested accretion flows, which are known to produce powerful jets via the Blandford–Znajek (BZ) mechanism. We find that the X-ray and γ -ray emission strongly depend on spin and inclination angle. Surprisingly, the high-energy power does not show the same dependence on spin as the BZ jet power, but instead can be understood as a redshift effect. In particular, photons observed perpendicular to the spin axis suffer little net redshift until originating from close to the horizon. Such observers see deeper into the hot, dense, highly magnetized inner disk region. This effect is largest for rapidly rotating black holes due to a combination of frame dragging and decreasing horizon radius. While the X-ray emission is dominated by the near horizon region, the near-infrared (NIR) radiation originates at larger radii. Therefore, the ratio of X-ray to NIR power is an observational signature of black hole spin.

  13. Overload control of artificial gravity facility using spinning tether system for high eccentricity transfer orbits

    Science.gov (United States)

    Gou, Xing-wang; Li, Ai-jun; Tian, Hao-chang; Wang, Chang-qing; Lu, Hong-shi

    2018-06-01

    As the major part of space life supporting systems, artificial gravity requires further study before it becomes mature. Spinning tether system is a good alternative solution to provide artificial gravity for the whole spacecraft other than additional devices, and its longer tether length could significantly reduce spinning velocity and thus enhance comfortability. An approximated overload-based feedback method is proposed to provide estimated spinning velocity signals for controller, so that gravity level could be accurately controlled without complicated GPS modules. System behavior in high eccentricity transfer orbits is also studied to give a complete knowledge of the spinning stabilities. The application range of the proposed method is studied in various orbit cases and spinning velocities, indicating that it is accurate and reliable for most of the mission phases especially for the final constant gravity level phase. In order to provide stable gravity level for transfer orbit missions, a sliding mode controller based on estimated angular signals is designed for closed-loop control. Numerical results indicate that the combination of overload-based feedback and sliding mode controller could satisfy most of the long-term artificial gravity missions. It is capable of forming flexible gravity environment in relatively good accuracy even in the lowest possible orbital radiuses and high eccentricity orbits of crewed space missions. The proposed scheme provides an effective tether solution for the artificial gravity construction in interstellar travel.

  14. Dual source multidetector CT-angiography before transcatheter aortic valve implantation (TAVI) using a high-pitch spiral acquisition mode

    Energy Technology Data Exchange (ETDEWEB)

    Wuest, W.; Anders, K.; May, M.S.; Uder, M. [University of Erlangen, Department of Radiology, Erlangen (Germany); Schuhbaeck, A.; Gauss, S.; Marwan, M.; Arnold, M.; Muschiol, G.; Daniel, W.G.; Achenbach, S. [University of Erlangen, Department of Cardiology, Erlangen (Germany); Ensminger, S. [University of Erlangen, Department of Cardiac Surgery, Erlangen (Germany)

    2012-01-15

    Transcatheter Aortic Valve Implantation (TAVI) is an alternative to surgical valve replacement in high risk patients. Angiography of the aortic root, aorta and iliac arteries is required to select suitable candidates, but contrast agents can be harmful due to impaired renal function. We evaluated ECG-triggered high-pitch spiral dual source Computed Tomography (CT) with minimized volume of contrast agent to assess aortic root anatomy and vascular access. 42 patients (82 {+-} 6 years) scheduled for TAVI underwent dual source (DS) CT angiography (CTA) of the aorta using a prospectively ECG-triggered high-pitch spiral mode (pitch = 3.4) with 40 mL iodinated contrast agent. We analyzed aortic root/iliac dimensions, attenuation, contrast to noise ratio (CNR), image noise and radiation exposure. Aortic root/iliac dimensions and distance of coronary ostia from the annulus could be determined in all cases. Mean aortic and iliac artery attenuation was 320 {+-} 70 HU and 340 {+-} 77 HU. Aortic/iliac CNR was 21.7 {+-} 6.8 HU and 14.5 {+-} 5.4 HU using 100 kV (18.8 {+-} 4.1 HU and 8.7 {+-} 2.6 HU using 120 kV). Mean effective dose was 4.5 {+-} 1.2 mSv. High-pitch spiral DSCTA can be used to assess the entire aorta and iliac arteries in TAVI candidates with a low volume of contrast agent while preserving diagnostic image quality. (orig.)

  15. High-fidelity projective read-out of a solid-state spin quantum register.

    Science.gov (United States)

    Robledo, Lucio; Childress, Lilian; Bernien, Hannes; Hensen, Bas; Alkemade, Paul F A; Hanson, Ronald

    2011-09-21

    Initialization and read-out of coupled quantum systems are essential ingredients for the implementation of quantum algorithms. Single-shot read-out of the state of a multi-quantum-bit (multi-qubit) register would allow direct investigation of quantum correlations (entanglement), and would give access to further key resources such as quantum error correction and deterministic quantum teleportation. Although spins in solids are attractive candidates for scalable quantum information processing, their single-shot detection has been achieved only for isolated qubits. Here we demonstrate the preparation and measurement of a multi-spin quantum register in a low-temperature solid-state system by implementing resonant optical excitation techniques originally developed in atomic physics. We achieve high-fidelity read-out of the electronic spin associated with a single nitrogen-vacancy centre in diamond, and use this read-out to project up to three nearby nuclear spin qubits onto a well-defined state. Conversely, we can distinguish the state of the nuclear spins in a single shot by mapping it onto, and subsequently measuring, the electronic spin. Finally, we show compatibility with qubit control: we demonstrate initialization, coherent manipulation and single-shot read-out in a single experiment on a two-qubit register, using techniques suitable for extension to larger registers. These results pave the way for a test of Bell's inequalities on solid-state spins and the implementation of measurement-based quantum information protocols. © 2011 Macmillan Publishers Limited. All rights reserved

  16. Cyclonic valve test: preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Monteiro, Andre Sampaio; Moraes, Carlos Alberto C.; Marins, Luiz Philipe M.; Soares, Fabricio; Oliveira, Dennis; Lima, Fabio Soares de; Airao, Vinicius [Petroleo Brasileiro S.A. (PETROBRAS), Rio de Janeiro, RJ (Brazil); Ton, Tijmen [Twister BV, Rijswijk (Netherlands)

    2012-07-01

    For many years, the petroleum industry has been developing a valve that input less shear to the flow for a given required pressure drop and this can be done using the cyclonic concept. This paper presents a comparison between the performances of a cyclonic valve (low shear) and a conventional globe valve. The aim of this work is to show the advantages of using a cyclonic low shear valve instead of the commonly used in the primary separation process by PETROBRAS. Tests were performed at PETROBRAS Experimental Center (NUEX) in Aracaju/SE varying some parameters: water cut; pressure loss (from 4 kgf/cm2 to 10 kgf/cm2); flow rates (30 m3/h and 45 m3/h). Results indicates a better performance of the cyclonic valve, if compared with a conventional one, and also that the difference of the performance, is a function of several parameters (emulsion stability, water content free, and oil properties). The cyclonic valve tested can be applied as a choke valve, as a valve between separation stages (for pressure drop), or for controlling the level of vessels. We must emphasize the importance to avoid the high shear imposed by conventional valves, because once the emulsion is created, it becomes more difficult to break it. New tests are being planned to occur in 2012, but PETROBRAS is also analyzing real cases where the applications could increase the primary process efficiency. In the same way, the future installations are also being designed considering the cyclonic valve usage. (author)

  17. Optimal design of high damping force engine mount featuring MR valve structure with both annular and radial flow paths

    International Nuclear Information System (INIS)

    Nguyen, Q H; Choi, S B; Lee, Y S; Han, M S

    2013-01-01

    This paper focuses on the optimal design of a compact and high damping force engine mount featuring magnetorheological fluid (MRF). In the mount, a MR valve structure with both annular and radial flows is employed to generate a high damping force. First, the configuration and working principle of the proposed MR mount is introduced. The MRF flows in the mount are then analyzed and the governing equations of the MR mount are derived based on the Bingham plastic behavior of the MRF. An optimal design of the MR mount is then performed to find the optimal structure of the MR valve to generate a maximum damping force with certain design constraints. In addition, the gap size of MRF ducts is empirically chosen considering the ‘lockup’ problem of the mount at high frequency. Performance of the optimized MR mount is then evaluated based on finite element analysis and discussions on performance results of the optimized MR mount are given. The effectiveness of the proposed MR engine mount is demonstrated via computer simulation by presenting damping force and power consumption. (paper)

  18. Optimal design of high damping force engine mount featuring MR valve structure with both annular and radial flow paths

    Science.gov (United States)

    Nguyen, Q. H.; Choi, S. B.; Lee, Y. S.; Han, M. S.

    2013-11-01

    This paper focuses on the optimal design of a compact and high damping force engine mount featuring magnetorheological fluid (MRF). In the mount, a MR valve structure with both annular and radial flows is employed to generate a high damping force. First, the configuration and working principle of the proposed MR mount is introduced. The MRF flows in the mount are then analyzed and the governing equations of the MR mount are derived based on the Bingham plastic behavior of the MRF. An optimal design of the MR mount is then performed to find the optimal structure of the MR valve to generate a maximum damping force with certain design constraints. In addition, the gap size of MRF ducts is empirically chosen considering the ‘lockup’ problem of the mount at high frequency. Performance of the optimized MR mount is then evaluated based on finite element analysis and discussions on performance results of the optimized MR mount are given. The effectiveness of the proposed MR engine mount is demonstrated via computer simulation by presenting damping force and power consumption.

  19. Note: Hollow cathode lamp with integral, high optical efficiency isolation valve: A modular vacuum ultraviolet source

    International Nuclear Information System (INIS)

    Sloan Roberts, F.; Anderson, Scott L.

    2013-01-01

    The design and operating conditions of a hollow cathode discharge lamp for the generation of vacuum ultraviolet radiation, suitable for ultrahigh vacuum (UHV) application, are described in detail. The design is easily constructed, and modular, allowing it to be adapted to different experimental requirements. A thin isolation valve is built into one of the differential pumping stages, isolating the discharge section from the UHV section, both for vacuum safety and to allow lamp maintenance without venting the UHV chamber. The lamp has been used both for ultraviolet photoelectron spectroscopy of surfaces and as a “soft” photoionization source for gas-phase mass spectrometry

  20. Note: Hollow cathode lamp with integral, high optical efficiency isolation valve: A modular vacuum ultraviolet source

    Energy Technology Data Exchange (ETDEWEB)

    Sloan Roberts, F.; Anderson, Scott L. [Department of Chemistry, University of Utah, 315 S. 1400 E., Salt Lake City, Utah 84112 (United States)

    2013-12-15

    The design and operating conditions of a hollow cathode discharge lamp for the generation of vacuum ultraviolet radiation, suitable for ultrahigh vacuum (UHV) application, are described in detail. The design is easily constructed, and modular, allowing it to be adapted to different experimental requirements. A thin isolation valve is built into one of the differential pumping stages, isolating the discharge section from the UHV section, both for vacuum safety and to allow lamp maintenance without venting the UHV chamber. The lamp has been used both for ultraviolet photoelectron spectroscopy of surfaces and as a “soft” photoionization source for gas-phase mass spectrometry.

  1. Note: Hollow cathode lamp with integral, high optical efficiency isolation valve: a modular vacuum ultraviolet source.

    Science.gov (United States)

    Roberts, F Sloan; Anderson, Scott L

    2013-12-01

    The design and operating conditions of a hollow cathode discharge lamp for the generation of vacuum ultraviolet radiation, suitable for ultrahigh vacuum (UHV) application, are described in detail. The design is easily constructed, and modular, allowing it to be adapted to different experimental requirements. A thin isolation valve is built into one of the differential pumping stages, isolating the discharge section from the UHV section, both for vacuum safety and to allow lamp maintenance without venting the UHV chamber. The lamp has been used both for ultraviolet photoelectron spectroscopy of surfaces and as a "soft" photoionization source for gas-phase mass spectrometry.

  2. Leak-thight seals got high pressure testing of pipes, tanks, valves

    International Nuclear Information System (INIS)

    Estrade, J.

    1985-01-01

    Leak-tight seals ensure quick, safe and efficient testing of pipes with plain-ended or flanged openings, valves with flanged or welded edges, manifields, recipients, etc. They are inserted into the pipe end manually then simply a slight turn of the seal treated wheel commences the pressure test. Hydraulic pressure is supplied by a pump through the inlet seal and air is purged through the outlet seal which then closes. The higher the pressure, the greater the sealing strength of the seal which prevents accidental unplugging. There are different types of seals: for interior plain-ended openings, for pipes with plain-ended opening, for flanged pipes. (author)

  3. Spin-polarized high-energy scattering of charged leptons on nucleons

    Energy Technology Data Exchange (ETDEWEB)

    Burkardt, M. [New Mexico State Univ., Las Cruces, NM (United States). Dept. of Physics; Miller, C.A. [TRIUMF, Vancouver, BC (Canada); Nowak, W.D. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

    2009-08-15

    The proton is a composite object with spin one-half, understood to contain highly relativistic spin one-half quarks exchanging spin-one gluons, each possibly with significant orbital angular momenta. While their fundamental interactions are well described by Quantum ChromoDynamics (QCD), our standard theory of the strong interaction, nonperturbative calculations of the internal structure of the proton based directly on QCD are beginning to provide reliable results. Most of our present knowledge of the structure of the proton is based on experimental measurements interpreted within the rich framework of QCD. An area presently attracting intense interest, both experimental and theoretical, is the relationship between the spin of the proton and the spins and orbital angular momenta of its constituents. While remarkable progress has been made, especially in the last decade, the discovery and investigation of new concepts have revealed that much more remains to be learned. This progress is reviewed and an outlook for the future is offered. (orig.)

  4. Spin-polarized high-energy scattering of charged leptons on nucleons

    International Nuclear Information System (INIS)

    Burkardt, M.; Nowak, W.D.

    2009-08-01

    The proton is a composite object with spin one-half, understood to contain highly relativistic spin one-half quarks exchanging spin-one gluons, each possibly with significant orbital angular momenta. While their fundamental interactions are well described by Quantum ChromoDynamics (QCD), our standard theory of the strong interaction, nonperturbative calculations of the internal structure of the proton based directly on QCD are beginning to provide reliable results. Most of our present knowledge of the structure of the proton is based on experimental measurements interpreted within the rich framework of QCD. An area presently attracting intense interest, both experimental and theoretical, is the relationship between the spin of the proton and the spins and orbital angular momenta of its constituents. While remarkable progress has been made, especially in the last decade, the discovery and investigation of new concepts have revealed that much more remains to be learned. This progress is reviewed and an outlook for the future is offered. (orig.)

  5. Universality, maximum radiation, and absorption in high-energy collisions of black holes with spin.

    Science.gov (United States)

    Sperhake, Ulrich; Berti, Emanuele; Cardoso, Vitor; Pretorius, Frans

    2013-07-26

    We explore the impact of black hole spins on the dynamics of high-energy black hole collisions. We report results from numerical simulations with γ factors up to 2.49 and dimensionless spin parameter χ=+0.85, +0.6, 0, -0.6, -0.85. We find that the scattering threshold becomes independent of spin at large center-of-mass energies, confirming previous conjectures that structure does not matter in ultrarelativistic collisions. It has further been argued that in this limit all of the kinetic energy of the system may be radiated by fine tuning the impact parameter to threshold. On the contrary, we find that only about 60% of the kinetic energy is radiated for γ=2.49. By monitoring apparent horizons before and after scattering events we show that the "missing energy" is absorbed by the individual black holes in the encounter, and moreover the individual black-hole spins change significantly. We support this conclusion with perturbative calculations. An extrapolation of our results to the limit γ→∞ suggests that about half of the center-of-mass energy of the system can be emitted in gravitational radiation, while the rest must be converted into rest-mass and spin energy.

  6. Development of a control system for compression and expansion cycles of critical valve for high vacuum systems

    Energy Technology Data Exchange (ETDEWEB)

    Agarwal, Jyoti, E-mail: jagarwal@ipr.res.in; Sharma, H.; Patel, Haresh; Gangradey, R.; Lambade, Vrushabh

    2016-11-15

    Highlights: • Control system with feedback loop of pressure gauge is developed for measuring the life cycle of vacuum isolation valve. • GUI based software developed for easy use and handling of control system. • Control system tested with an experiment showcasing the capability of the control system. • Control system can operate valve based on pressure inside the chamber, which helps to know the degradation of sealing capabilities of valve. • Control system can monitor the total closing and opening time of valve, cycles and pressure inside the vessel. - Abstract: A control system with feedback loop is designed, developed and tested to monitor the life cycles of the axial valve and bellows used in vacuum valves. The control system monitors number of compression cycles of any bellow or closing and opening cycle of a valve. It also interfaces vacuum gauges or pressure gauges to get pressure values inside the system. To find life cycle of valve, the developed control and monitoring system is integrated with an axial valve experimental test set up. In this system, feedback from the vacuum gauge attached to valve enclosure, is given and the life cycle test is automated. This paper describes the control and monitoring system in details and briefs the experiment carried out for valve life cycle. The same system can be used for life cycle estimate for bellows. A suitable GUI is also developed to control the function of the components and resister the number of cycles.

  7. Proton radioactivity at non-collective prolate shape in high spin state of 94Ag

    International Nuclear Information System (INIS)

    Aggarwal, Mamta

    2010-01-01

    We predict proton radioactivity and structural transitions in high spin state of an excited exotic nucleus near proton drip line in a theoretical framework and investigate the nature and the consequences of the structural transitions on separation energy as a function of temperature and spin. It reveals that the rotation of the excited exotic nucleus 94 Ag at excitation energies around 6.7 MeV and angular momentum near 21h generates a rarely seen prolate non-collective shape and proton separation energy becomes negative which indicates proton radioactivity in agreement with the experimental results of Mukha et al. for 94 Ag.

  8. Proton radioactivity at non-collective prolate shape in high spin state of {sup 94}Ag

    Energy Technology Data Exchange (ETDEWEB)

    Aggarwal, Mamta, E-mail: mamta.a4@gmail.co [UM-DAE Centre for Excellence in Basic Sciences, University of Mumbai, Kalina Campus, Mumbai 400 098 (India)

    2010-10-11

    We predict proton radioactivity and structural transitions in high spin state of an excited exotic nucleus near proton drip line in a theoretical framework and investigate the nature and the consequences of the structural transitions on separation energy as a function of temperature and spin. It reveals that the rotation of the excited exotic nucleus {sup 94}Ag at excitation energies around 6.7 MeV and angular momentum near 21h generates a rarely seen prolate non-collective shape and proton separation energy becomes negative which indicates proton radioactivity in agreement with the experimental results of Mukha et al. for {sup 94}Ag.

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

    International Nuclear Information System (INIS)

    Kaneko, Kazunari

    1991-01-01

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

  10. Investigations of low- and high-spin states of sup 1 sup 3 sup 2 La

    CERN Document Server

    Kumar, V; Singh, R P; Muralithar, S; Bhowmik, R K

    2003-01-01

    The fusion evaporation reaction sup 1 sup 2 sup 2 Sn( sup 1 sup 4 N,4n) sup 1 sup 3 sup 2 La was used to populate the high-spin states of sup 1 sup 3 sup 2 La at the beam energy of 60 MeV. A new band consisting of mostly E2 transitions has been discovered. This band has the interesting links to the ground state 2 sup - and the isomeric state 6 sup -. A new transition of energy 351 keV connecting the low-spin states of the positive-parity band based on the pi h sub 1 sub 1 sub / sub 2 x nu h sub 1 sub 1 sub / sub 2 particle configuration, has been found. This has played a very important role in resolving the existing ambiguities and inconsistencies in the spin assignment of the band head. (orig.)

  11. Summary of the 8th international symposium on high energy spin physics

    International Nuclear Information System (INIS)

    Bunce, G.

    1988-01-01

    The series of conferences on high energy spin physics dates back to Argonne, 1974, and the first use of the polarized proton beam at the ZGS. This conference is unique in that it is concerned both with the technology of spin and with particle physics: particle physicists need to know what experiments might be possible and target/beam/source physicists want to know what their work will lead to, and get new ideas. In many cases, and I believe that this is central to the success of spin physics and of this conference series, these are the same people. This summary will have three basic parts: where we are now relative to Argonne in 1974; a discussion of new experiments and theory---there were many new and intriguing results presented here; and new ideas for polarized sources, beams, and targets which point toward an exciting future program of particle physics. 13 refs., 2 figs., 4 tabs

  12. PROCEEDINGS OF RIKEN BNL RESEARCH CENTER WORKSHOP CIRCUM-PAN-PACIFIC RIKEN SYMPOSIUM ON HIGH ENERGY SPIN PHYSICS, VOLUME 25

    Energy Technology Data Exchange (ETDEWEB)

    KUMANO,S.; SHIBATA,T.A.; YAZAKI,K.

    2000-06-28

    The Circum-Pan-Pacific Riken Symposium on High Energy Spin Physics was held at Oukouchi Memorial Hall in Riken from November 3 through 6, 1999. It was held as a joint meeting of the 2nd Circum-Pan-Pacific Symposium on High Energy Spin Physics and the 3rd of the series of Riken Symposia related to the RHIC-SPIN. The 1st Circum-Pan-Pacific Symposium on High Energy Spin Physics was held at Kobe in 1996 and the RHIC-SPIN Riken Symposia had been held every two years since 1995. As Prof. Ozaki mentioned in his talk at the beginning of this meeting, the RHIC was ready for the first beam, physics experiments scheduled in 2000, and the RHIC-SPIN would start in 2001. It was therefore considered to be very timely for the researchers in the field of high energy spin physics to get together, clarifying the present status of the field and discussing interesting and important topics as well as experimental subjects to be pursued. It is especially important for the success of the RHIC-SPIN project that the researchers in the neighboring countries surrounding the Pacific are actively involved in it. This is why the above two series were joined in this. symposium. The subjects discussed in the symposium include: Hard processes probing spin-structure functions, polarization mechanisms in high energy reactions, lattice studies of polarized structure functions, theoretical models for the nucleon and its spin structure, RHIC and RHIC-SPIN projects, results and future projects of existing experimental facilities. Totally 73 scientists participated in the symposium, 27 from abroad and 46 from Japan. it consisted of 13 main sessions, with 33 invited and contributed talks, and 4 discussion sessions covering recent experimental and theoretical developments and important topics in high energy spin physics and closely related fields.

  13. High-resolution, high-sensitivity NMR of nano-litre anisotropic samples by coil spinning

    Energy Technology Data Exchange (ETDEWEB)

    Sakellariou, D [CEA Saclay, DSM, DRECAM, SCM, Lab Struct and Dynam Resonance Magnet, CNRS URA 331, F-91191 Gif Sur Yvette, (France); Le Goff, G; Jacquinot, J F [CEA Saclay, DSM, DRECAM, SPEC: Serv Phys Etat Condense, CNRS URA 2464, F-91191 Gif Sur Yvette, (France)

    2007-07-01

    Nuclear magnetic resonance (NMR) can probe the local structure and dynamic properties of liquids and solids, making it one of the most powerful and versatile analytical methods available today. However, its intrinsically low sensitivity precludes NMR analysis of very small samples - as frequently used when studying isotopically labelled biological molecules or advanced materials, or as preferred when conducting high-throughput screening of biological samples or 'lab-on-a-chip' studies. The sensitivity of NMR has been improved by using static micro-coils, alternative detection schemes and pre-polarization approaches. But these strategies cannot be easily used in NMR experiments involving the fast sample spinning essential for obtaining well-resolved spectra from non-liquid samples. Here we demonstrate that inductive coupling allows wireless transmission of radio-frequency pulses and the reception of NMR signals under fast spinning of both detector coil and sample. This enables NMR measurements characterized by an optimal filling factor, very high radio-frequency field amplitudes and enhanced sensitivity that increases with decreasing sample volume. Signals obtained for nano-litre-sized samples of organic powders and biological tissue increase by almost one order of magnitude (or, equivalently, are acquired two orders of magnitude faster), compared to standard NMR measurements. Our approach also offers optimal sensitivity when studying samples that need to be confined inside multiple safety barriers, such as radioactive materials. In principle, the co-rotation of a micrometer-sized detector coil with the sample and the use of inductive coupling (techniques that are at the heart of our method) should enable highly sensitive NMR measurements on any mass-limited sample that requires fast mechanical rotation to obtain well-resolved spectra. The method is easy to implement on a commercial NMR set-up and exhibits improved performance with miniaturization, and we

  14. Investigation of high spin structure of N ∼ 28 nuclei with PHF model

    International Nuclear Information System (INIS)

    Naik, Z.

    2016-01-01

    Nucleus in 50 mass shows verity of high spin phenomena. Some of them are K-Isomer, Band termination, States Beyond Band termination, Superdeformed Structure, Shape co-existence and many more. Some of these phenomena with Projected Hartree-Fock (PHF) model are addressed and the microscopic structure associate with them is discussed

  15. Formation of the high-spin Hf-179m2 isomer in reactor irradiations

    Czech Academy of Sciences Publication Activity Database

    Karamian, S. A.; Carroll, J. J.; Adam, Jindřich; Kulagin, EN.; Shabalin, EP.

    2004-01-01

    Roč. 14, č. 4 (2004), s. 438-441 ISSN 1054-660X R&D Projects: GA MŠk(CZ) ME 134 Keywords : reactor irradiation * high-spin Hf-179m2 Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 0.836, year: 2004

  16. Shell structure at high spin and the influence on nuclear shapes

    International Nuclear Information System (INIS)

    Khoo, T.L.; Chowdhury, P.; Ahmad, I.

    1982-01-01

    Nuclear structure at high spin is influenced by a combination of liquid-drop and shell-structure effects. For N 90. The competition between oblate and prolate driving effects leads to a prolate-to-oblate shape transition in 154 Dy 88 . The role of rotation-aligned configurations in the shape change is discussed

  17. Non-collective oblate states in iodine isotopes at high spin

    Energy Technology Data Exchange (ETDEWEB)

    Paul, E S; Ali, I; Cullen, D M; Fallon, P; Forbes, S A; Hanna, F; Nolan, P J [Liverpool Univ. (United Kingdom). Oliver Lodge Lab.; Bentley, M A; Bruce, A M; Simpson, J [Daresbury Lab. (United Kingdom); Clark, R M; Regan, P H; Wadsworth, R [York Univ. (United Kingdom). Dept. of Physics; Fossan, D B; Hughes, J R; Lafosse, D R; Vaska, P; Waring, M P [Department of Physics, SUNY at Stony Brook, NY (United States); Liang, Y [Argonne National Lab., IL (United States); Ma, R [Brookhaven National Lab., Upton, NY (United States)

    1992-08-01

    Competition between single-particle and collective modes of excitation has been observed in the odd-A {sup 113-119}I isotopes at high spin. A maximally-aligned non-collective 43/2{sup -} configuration at {gamma}=+ 60 degrees is seen at similar excitation energies in these nuclei. 7 refs., 4 figs.

  18. Spin polarization versus color–flavor locking in high-density quark matter

    DEFF Research Database (Denmark)

    Tsue, Yasuhiko; da Providência, João; Providência, Constança

    2015-01-01

    It is shown that spin polarization with respect to each flavor in three-flavor quark matter occurs instead of color–flavor locking at high baryon density by using the Nambu–Jona-Lasinio model with four-point tensor-type interaction. Also, it is indicated that the order of phase transition between...

  19. Electron spin transition causing structure transformations of earth's interiors under high pressure

    Science.gov (United States)

    Yamanaka, T.; Kyono, A.; Kharlamova, S.; Alp, E.; Bi, W.; Mao, H.

    2012-12-01

    To elucidate the correlation between structure transitions and spin state is one of the crucial problems for understanding the geophysical properties of earth interiors under high pressure. High-pressure studies of iron bearing spinels attract extensive attention in order to understand strong electronic correlation such as the charge transfer, electron hopping, electron high-low spin transition, Jahn-Teller distortion and charge disproponation in the lower mantle or subduction zone [1]. Experiment Structure transitions of Fe3-xSixO4, Fe3-xTixO4 Fe3-xCrxO4 spinel solid solution have been investigated at high pressure up to 60 GPa by single crystal and powder diffraction studies using synchrotron radiation with diamond anvil cell. X-ray emission experiment (XES) at high pressure proved the spin transition of Fe-Kβ from high spin (HS) to intermediate spin state (IS) or low spin state (LS). Mössbauer experiment and Raman spectra study have been also conducted for deformation analysis of Fe site and confirmation of the configuration change of Fe atoms. Jahn-Teller effect A cubic-to-tetragonal transition under pressure was induced by Jahn-Teller effect of IVFe2+ (3d6) in the tetrahedral site of Fe2TiO4 and FeCr2O4, providing the transformation from 43m (Td) to 42m (D2d). Tetragonal phase is formed by the degeneracy of e orbital of Fe2+ ion. Their c/a ratios are c/adisordered in the M2 site. At pressures above 53 GPa, Fe2TiO4 structure further transforms to Pmma. This structure change results in the order-disorder transition [2]. New structure of Fe2SiO4 The spin transition exerts an influence to Fe2SiO4 spinel structure and triggers two distinct curves of the lattice constant in the spinel phase. The reversible structure transition from cubic to pseudo-rhombohedral phase was observed at about 45 GPa. This transition is induced by the 20% shrinkage of ionic radius of VIFe2+at the low sin state. Laser heating experiment at 1500 K has confirmed the decomposition from the

  20. High-spin structure of 121Xe: triaxiality, band termination and signature inversion

    International Nuclear Information System (INIS)

    Timar, J.; Paul, E.S.; Beausang, C.W.; Joyce, M.J.; Sharpey-Schafer, J.F.

    1995-01-01

    High-spin states of the odd-neutron 121 Xe nucleus have been studied with Eurogam using the 96 Zr( 30 Si, 5n) 121 Xe fusion-evaporation reaction. The level scheme has been extended up to a tentative spin of 67/2h at an excitation energy of ∼ 14 MeV. Several new rotational bands have been observed and the previously known bands extended. Two of them lose their regular character at high spins, which may be interpreted as transition from collective behaviour to a regime of noncollective oblate states. The deduced high-spin structure is compared to Woods-Saxon TRS cranking and CSM calculations. Configurations of the bands have been suggested. The νh 1 1/2 band is interpreted as having a triaxial shape. Signature inversion and an unexpectedly large staggering of the B(M1)/B(E2) ratios has been found for one of the bands. Enhanced E1 transitions have been observed between the νd 5/2 and the νh 1 1/2 bands. (orig.)

  1. Impact characteristics for high-pressure large-flow water-based emulsion pilot operated check valve reverse opening

    Science.gov (United States)

    Liu, Lei; Huang, Chuanhui; Yu, Ping; Zhang, Lei

    2017-10-01

    To improve the dynamic characteristics and cavitation characteristics of large-flow pilot operated check valve, consider the pilot poppet as the research object, analyses working principle and design three different kinds of pilot poppets. The vibration characteristics and impact characteristics are analyzed. The simulation model is established through flow field simulation software. The cavitation characteristics of large-flow pilot operated check valve are studied and discussed. On this basis, high-pressure large-flow impact experimental system is used for impact experiment, and the cavitation index is discussed. Then optimal structure is obtained. Simulation results indicate that the increase of pilot poppet half cone angle can effectively reduce the cavitation area, reducing the generation of cavitation. Experimental results show that the pressure impact is not decreasing with increasing of pilot poppet half cone angle in process of unloading, but the unloading capacity, response speed and pilot poppet half cone angle are positively correlated. The impact characteristics of 60° pilot poppet, and its cavitation index is lesser, which indicates 60° pilot poppet is the optimal structure, with the theory results are basically identical.

  2. Environmentally friendly and highly productive bi-component melt spinning of thermoregulated smart polymer fibres with high latent heat capacity

    Directory of Open Access Journals (Sweden)

    Ch. Cherif

    2018-03-01

    Full Text Available A stable and reproducible bi-component melt spinning process on an industrial scale incorporating Phase Change Material (PCM into textile fibres has been successfully developed and carried out using a melt spinning machine. The key factor for a successful bi-component melt spinning process is that a deep insight into the thermal and rheological behaviour of PCM using Difference Scanning Calorimetry (DSC, Thermogravimetric Analysis (TGA, and an oscillatory rheological investigation. PCM is very sensitive to the temperature and residence time of the melt spinning process. It is found that the optimal process temperature of PCM is 210 °C. The textile-physical properties and the morphology of the melt spun and further drawn bi-component core and sheath fibres (bico fibres were investigated and interpreted. The heat capacities of PCM incorporated in bico fibres were also determined by means of DSC. The melt spun bico fibres integrating PCM provide a high latent heat of up to 22 J/g, which is three times higher than that of state-of-the-art fibres, which were also obtained using the melt spinning process. Therefore, they have the potential to be used as smart polymer fibres for textile and other technical applications.

  3. Endohedral Metallofullerene as Molecular High Spin Qubit: Diverse Rabi Cycles in Gd2@C79N.

    Science.gov (United States)

    Hu, Ziqi; Dong, Bo-Wei; Liu, Zheng; Liu, Jun-Jie; Su, Jie; Yu, Changcheng; Xiong, Jin; Shi, Di-Er; Wang, Yuanyuan; Wang, Bing-Wu; Ardavan, Arzhang; Shi, Zujin; Jiang, Shang-Da; Gao, Song

    2018-01-24

    An anisotropic high-spin qubit with long coherence time could scale the quantum system up. It has been proposed that Grover's algorithm can be implemented in such systems. Dimetallic aza[80]fullerenes M 2 @C 79 N (M = Y or Gd) possess an unpaired electron located between two metal ions, offering an opportunity to manipulate spin(s) protected in the cage for quantum information processing. Herein, we report the crystallographic determination of Gd 2 @C 79 N for the first time. This molecular magnet with a collective high-spin ground state (S = 15/2) generated by strong magnetic coupling (J Gd-Rad = 350 ± 20 cm -1 ) has been unambiguously validated by magnetic susceptibility experiments. Gd 2 @C 79 N has quantum coherence and diverse Rabi cycles, allowing arbitrary superposition state manipulation between each adjacent level. The phase memory time reaches 5 μs at 5 K by dynamic decoupling. This molecule fulfills the requirements of Grover's searching algorithm proposed by Leuenberger and Loss.

  4. High-spin states of 39K and 42Ca, ch. 4

    International Nuclear Information System (INIS)

    Eggenhuisen, H.H.; Elstrom, L.P.; Engelbertink, G.A.P.; Aarts, H.J.M.

    1978-01-01

    High-spin states of 39 K and 42 Ca have been investigated with the 28 Si( 16 O, αpγ) 39 K and 28 Si( 16 O, 2pγ) 42 Ca reactions at a beam energy of 45 MeV. Gamma-gamma coincidence, γ-ray angular distribution and linear polarization measurements were performed with a Ge(Li)-NaI(Tl) Compton suppression spectrometer and a three-crystal Ge(Li) Compton polarimeter. High-spin states of 39 K at Esub(x)=7.14, 7.78 and 8.03 and of 42 Ca at Esub(x)=7.75 MeV are established. Unambiguous spin-parity assignments of Jsup(π)=11/2 - , 13/2 - , 15/2 + , 15/2 - , 17/2 + and 19/2 - to the 39 K levels at Esub(x)=5.35, 5.72, 6.48, 7.14, 7.78 and 8.03 MeV and of 6 - , 7 - , 8 - , 9 - and (8,10) to the 42 Ca levels at Esub(x)=5.49, 6.15, 6.41, 6.55 and 7.37 MeV, respectively, have been obtained. Further spin-parity restrictions, lifetime limits, excitation energies, branching ratios and multipole mixing ratios are reported. Discrepancies with previous Jsup(π) assignments are discussed in detail. (Auth.)

  5. Resonance Analysis of High-Frequency Electrohydraulic Exciter Controlled by 2D Valve

    Directory of Open Access Journals (Sweden)

    Guojun Pan

    2015-01-01

    Full Text Available The resonant characteristic of hydraulic system has not been described yet because it is necessarily restricted by linear assumptions in classical fluid theory. A way of the resonance analysis is presented for an electrohydraulic exciter controlled by 2D valve. The block diagram of this excitation system is established by extracting nonlinear parts from the traditional linearization analysis; as a result the resonant frequency is obtained. According to input energy from oil source which is equal to the reverse energy to oil source, load pressure and load flow are solved analytically as the working frequency reaches the natural frequency. The analytical expression of resonant peak is also derived without damping. Finally, the experimental system is built to verify the theoretical analysis. The initial research on resonant characteristic will lay theoretical foundation and make useful complement for resonance phenomena of classical fluid theory in hydraulic system.

  6. Properties of neutron-rich hafnium high-spin isomers

    CERN Multimedia

    Tungate, G; Walker, P M; Neyens, G; Billowes, J; Flanagan, K; Koester, U H; Litvinov, Y

    It is proposed to study highly-excited multi-quasiparticle isomers in neutron-rich hafnium (Z=72) isotopes. Long half-lives have already been measured for such isomers in the storage ring at GSI, ensuring their accessibility with ISOL production. The present proposal focuses on:\\\\ (i) an on-line experiment to measure isomer properties in $^{183}$Hf and $^{184}$Hf, and\\\\ (ii) an off-line molecular breakup test using REXTRAP, to provide Hf$^{+}$ beams for future laser spectroscopy and greater sensitivity for the future study of more neutron-rich isotopes.

  7. Discovery of highly spin-polarized conducting surface states in the strong spin-orbit coupling semiconductor Sb2Se3

    Science.gov (United States)

    Das, Shekhar; Sirohi, Anshu; Kumar Gupta, Gaurav; Kamboj, Suman; Vasdev, Aastha; Gayen, Sirshendu; Guptasarma, Prasenjit; Das, Tanmoy; Sheet, Goutam

    2018-06-01

    Majority of the A2B3 -type chalcogenide systems with strong spin-orbit coupling (SOC), such as Bi2Se3,Bi2Te3 , and Sb2Te3 , etc., are topological insulators. One important exception is Sb2Se3 where a topological nontrivial phase was argued to be possible under ambient conditions, but such a phase could be detected to exist only under pressure. In this paper, we show that Sb2Se3 like Bi2Se3 displays a generation of highly spin-polarized current under mesoscopic superconducting point contacts as measured by point-contact Andreev reflection spectroscopy. In addition, we observe a large negative and anisotropic magnetoresistance of the mesoscopic metallic point contacts formed on Sb2Se3 . Our band-structure calculations confirm the trivial nature of Sb2Se3 crystals and reveal two trivial surface states one of which shows large spin splitting due to Rashba-type SOC. The observed high spin polarization and related phenomena in Sb2Se3 can be attributed to this spin splitting.

  8. High spin states excited by the (p, t) reaction on lead isotopes

    Energy Technology Data Exchange (ETDEWEB)

    Kumabe, I.; Hyakutake, M. [Kyushu Univ., Fukuoka (Japan). Faculty of Engineering; Yuasa, K.; Yamagata, T.; Kishimoto, S.; Ikegami, H.; Muraoka, M [eds.

    1980-01-01

    In order to find high spin states the sup(204, 206, 208)Pb (p, t) reactions have been investigated with RCNP isochronous cyclotron and a high resolution magnetic spectrograph ''RAIDEN''. The experimental angular distributions were analyzed by DWBA calculations, and the lowest 10/sup +/, 12/sup +/ (i sub(13/2))/sup 2/ and 11/sup -/ (i sub(13/2), h sub(9/2)) states in /sup 202/Pb, /sup 204/Pb and /sup 206/Pb were established.

  9. Double-disc gate valve

    International Nuclear Information System (INIS)

    Wheatley, S.J.

    1979-01-01

    The invention relates to an improvement in a conventional double-disc gate valve having a vertically movable gate assembly including a wedge, spreaders slidably engaged therewith, a valve disc carried by the spreaders. When the gate assembly is lowered to a selected point in the valve casing, the valve discs are moved transversely outward to close inlet and outlet ports in the casing. The valve includes hold-down means for guiding the disc-and-spreader assemblies as they are moved transversely outward and inward. If such valves are operated at relatively high differential pressures, they sometimes jam during opening. Such jamming has been a problem for many years in gate valves used in gaseous diffusion plants for the separation of uranium isotopes. The invention is based on the finding that the above-mentioned jamming results when the outlet disc tilts about its horizontal axis in a certain way during opening of the valve. In accordance with the invention, tilting of the outlet disc is maintained at a tolerable value by providing the disc with a rigid downwardly extending member and by providing the casing with a stop for limiting inward arcuate movement of the member to a preselected value during opening of the valve

  10. Entanglement and magnetism in high-spin graphene nanodisks

    Science.gov (United States)

    Hagymási, I.; Legeza, Ö.

    2018-01-01

    We investigate the ground-state properties of triangular graphene nanoflakes with zigzag edge configurations. The description of zero-dimensional nanostructures requires accurate many-body techniques since the widely used density-functional theory with local density approximation or Hartree-Fock methods cannot handle the strong quantum fluctuations. Applying the unbiased density-matrix renormalization group algorithm we calculate the magnetization and entanglement patterns with high accuracy for different interaction strengths and compare them to the mean-field results. With the help of quantum information analysis and subsystem density matrices we reveal that the edges are strongly entangled with each other. We also address the effect of electron and hole doping and demonstrate that the magnetic properties of triangular nanoflakes can be controlled by an electric field, which reveals features of flat-band ferromagnetism. This may open up new avenues in graphene based spintronics.

  11. High spin K isomeric target of 177mLu

    International Nuclear Information System (INIS)

    Roig, O.; Belier, G.; Daugas, J.-M.; Delbourgo, P.; Maunoury, L.; Meot, V.; Morichon, E.; Sauvestre, J.-E.; Aupiais, J.; Boulin, Y.; Fioni, G.; Letourneau, A.; Marie, F.; Ridikas, D.

    2004-01-01

    The techniques used to produce a 177m Lu (J π =23/2 - ,T 1/2 =160.4 days) target are described in this paper. Firstly, an isotopic separation of an enriched lutetium sample was used to reach a purity of 176 Lu close to 99.993%. Afterwards, the high neutron flux of the Grenoble Institut Laue-Langevin reactor was used to produce the 177m Lu isomer by the 176 Lu(n,γ) reaction. Finally, a chemical separation was performed to extract 10 13 nuclei of 177m Lu. Thanks to this experiment, we have been able to estimate the destruction cross-section of the 177m Lu

  12. Laser-assisted spin-polarized transport in graphene tunnel junctions

    International Nuclear Information System (INIS)

    Ding Kaihe; Zhu Zhengang; Berakdar, Jamal

    2012-01-01

    The Keldysh nonequilibrium Green’s function method is utilized to theoretically study spin-polarized transport through a graphene spin valve irradiated by a monochromatic laser field. It is found that the bias dependence of the differential conductance exhibits successive peaks corresponding to the resonant tunneling through the photon-assisted sidebands. The multi-photon processes originate from the combined effects of the radiation field and the graphene tunneling properties, and are shown to be substantially suppressed in a graphene spin valve which results in a decrease of the differential conductance for a high bias voltage. We also discuss the appearance of a dynamical gap around zero bias due to the radiation field. The gap width can be tuned by changing the radiation electric field strength and the frequency. This leads to a shift of the resonant peaks in the differential conductance. We also demonstrate numerically the dependences of the radiation and spin valve effects on the parameters of the external fields and those of the electrodes. We find that the combined effects of the radiation field, the graphene and the spin valve properties bring about an oscillatory behavior in the tunnel magnetoresistance, and this oscillatory amplitude can be changed by scanning the radiation field strength and/or the frequency. (paper)

  13. Discrete spectroscopy in {sup 180}Os at high spins

    Energy Technology Data Exchange (ETDEWEB)

    Marti, G; Venkova, Ts; Morek, T; Schnare, H; Gast, W; Georgiev, A; Spohr, K M; Lieder, R M [Institut fuer Kernphysik, KFA-Juelich (Germany); Maier, K H [Hahn-Meitner-Institut Berlin GmbH (Germany); Zell, K O [Institut fuer Kernphysik, Universitaet Koeln (Germany)

    1992-08-01

    New information on rotational bands in {sup 180}Os was obtained from a discrete spectroscopy experiment in which the final nucleus was populated through the {sup 150}Nd({sup 36}S,6n) reaction at 177 MeV. A new strongly-coupled rotational band starting at a relatively high excitation energy was found. The observation and placement of the 185.6 keV in the level scheme gives strong support to a hypothetical 2-quasineutron configuration assigned to the 7{sup -} isomeric bands in {sup 180}Os and the isotone {sup 178}W. Band mixing between the (-,1){sub 1} and (-,1){sub 3} bands of same parity and signature was observed, and the interaction strength was estimated from experimental branching ratios. The authors` results confirm a previous assignment for the yrast and yrare sequences in this nucleus. With the identification of new transitions above the states with I {approx_equal} 24, previously assigned bands had to be revised, with the result that the second band crossing vanishes. 23 refs., 3 figs.

  14. High spin spectroscopy for A ∼ 160 nuclei

    International Nuclear Information System (INIS)

    Yu, C.-H.

    1989-01-01

    Experimental routhians, alignments, band crossing frequencies, and the B(M1)/B(E2) ratios of the N = 90 isotopes and several light Lu (N = 90--96) isotopes are summarized and discussed in terms of shape changes. These systematic analyses show a neutron and proton number dependent deformations (both quadruple and γ deformations) for these light rare earth nuclei. The stability of the nuclear deformation with respect to β and γ is also found to be particle number dependent. Such particle number dependent shapes can be attributed to the different locations of the proton and neutron Fermi levels in the Nilsson diagrams. Configurations dependent shapes are discussed specially concerned the deformation difference between the proton h 9/2 1/2 - [541] and the high-K h 11/2 configurations. The observed large neutron band crossing frequencies in the h 9/2 1/2 - [541] configuration support the predicted large deformation of this configuration but can be reproduced by the cranked shell model calculation according to the predicted deformations. Lifetime measurement for 157 Ho, one of the nuclei that show a large ℎω c in the 1/2 - [541] band, indicates that deformation difference can only account for 20% of such shift in ℎω c . 55 refs., 12 figs

  15. Studies on the decay of high-spin isomers in the W and Os isotopes

    International Nuclear Information System (INIS)

    Kraemer-Flecken, A.

    1988-01-01

    From the two experiments performed on the nucleus 180 Os the properties of the new high-spin isomer could be found. The excitation energy amounts to 5208 keV and the spin of the isomer amounts probably to I=19ℎ. The new measured half-life amounts to T 1/2 =41±10 ns. It is populated with an intensity of 1.6±0.4% relative to the (4 + → 2 +) transition in the Yrast band in an experiment with out use of the recoil-shadow technique. A preliminary decay scheme could be established from the sum spectra and exhibits similarities with the decay of the high-spin isomer in 182 Os. From the analysis of the experiment on the nucleus 178 W a new isomer with an excitation energy of 5271 keV and a half-life of T 1/2 =39±10 ns could be identified. The spin of the level has been determined to I=20±1. The half-life of the 3527 keV isomer has been determined to T 1/2 =28±4 ns. The spin of the isomer could be determined from the analysis of DCO ratios to I π =14 - . The configuration of the isomer could be fixed to ν6 + 5/2 - 5 512 7 x 7/2 5 514 7 +π8 - 7/2 + 5 404 7 x 9/2 5 514 7 because of the comparison with the 14 - isomer in 176 Hf and the comparison of the excitation energy for certain configurations with I π =14 - . (orig./HSI)

  16. Hot nuclei with high spin states in collisions between heavy nuclei

    International Nuclear Information System (INIS)

    Galin, J.

    1991-01-01

    In the first part of this contribution we have shown that pretty hot nuclei could be obtained in peripheral collisions of Kr+Au. The collisions considered in the chosen example give rise to a nucleus of Z=28 with a kinetic energy of 1600 MeV (i.e. a velocity close to 27 MeV/u to be compared with the 32 MeV/u of the beam). The excitation energy deposited in the non-detected target like-nucleus, deduced from the neutron multiplicity measurements, amounts to 700 MeV (T= 6 MeV). In the second part of the contribution one used the well known properties of fission, and particularly its sensitivity to spin, to show in a qualitative way that pretty high spin values are into play. A more quantitative analysis together with additional measurements are still needed in order to infer precise figures of spin. It can be noted that for the 29 MeV/u Pb+Au reaction 1 max amounts to 1700 ℎ. If we assume that the sticking or rolling conditions can be fulfilled for initial angular momenta of about 2/3 1 max , then a projectile-like (and its target partner) could acquire an intrinsic spin of about 160 ℎ. The behavior of a Pb-like nucleus brought in such an exotic state (T=6 MeV and J=160ℎ)) is certainly worth to be studied in detail. It is also worth recalling that, when obtained in peripheral collisions, the hot nuclei thus formed do not suffer much initial compression at variance with what happens in more central collisions. There is thus an interesting field to be explored of hot, high spin but uncompressed nuclei

  17. Spin 1990

    International Nuclear Information System (INIS)

    Anton, Gisela

    1990-01-01

    The idea of the intrinsic angular momentum, or 'spin', of a particle has played an essential part in fundamental physics for more than 60 years, and its continuing importance was underlined at the 9th International Symposium on High Energy Spin Physics, held in September in Bonn.

  18. Spin 1990

    Energy Technology Data Exchange (ETDEWEB)

    Anton, Gisela

    1990-12-15

    The idea of the intrinsic angular momentum, or 'spin', of a particle has played an essential part in fundamental physics for more than 60 years, and its continuing importance was underlined at the 9th International Symposium on High Energy Spin Physics, held in September in Bonn.

  19. Piezoelectric valve

    Science.gov (United States)

    Petrenko, Serhiy Fedorovich

    2013-01-15

    A motorized valve has a housing having an inlet and an outlet to be connected to a pipeline, a saddle connected with the housing, a turn plug having a rod, the turn plug cooperating with the saddle, and a drive for turning the valve body and formed as a piezoelectric drive, the piezoelectric drive including a piezoelectric generator of radially directed standing acoustic waves, which is connected with the housing and is connectable with a pulse current source, and a rotor operatively connected with the piezoelectric generator and kinematically connected with the rod of the turn plug so as to turn the turn plug when the rotor is actuated by the piezoelectric generator.

  20. Antiferromagnetic spin-orbitronics

    KAUST Repository

    Manchon, Aurelien; Saidaoui, Hamed Ben Mohamed; Ghosh, Sumit

    2015-01-01

    Antiferromagnets have long remained an intriguing and exotic state of matter, whose application has been restricted to enabling interfacial exchange bias in metallic and tunneling spin-valves [1]. Their role in the expanding field of applied spintronics has been mostly passive and the in-depth investigation of their basic properties mostly considered from a fundamental perspective.

  1. Antiferromagnetic spin-orbitronics

    KAUST Repository

    Manchon, Aurelien

    2015-05-01

    Antiferromagnets have long remained an intriguing and exotic state of matter, whose application has been restricted to enabling interfacial exchange bias in metallic and tunneling spin-valves [1]. Their role in the expanding field of applied spintronics has been mostly passive and the in-depth investigation of their basic properties mostly considered from a fundamental perspective.

  2. Injection and Scattering of Polarized Spins at Nanoscale Polymer Interfaces

    National Research Council Canada - National Science Library

    Epstein, Arthur J

    2004-01-01

    We made excellent progress several directions. We demonstrated that V[TCNE]̃2 is a room temperature fully spin polarized magnetic semiconductor of interest for spintronic applications, including spin valves...

  3. Topological Material-Based Spin Devices

    Science.gov (United States)

    Zhang, Minhao; Wang, Xuefeng

    Three-dimensional topological insulators have insulating bulk and gapless helical surface states. One of the most fascinating properties of the metallic surface states is the spin-momentum helical locking. The giant current-driven torques on the magnetic layer have been discovered in TI/ferromagnet bilayers originating from the spin-momentum helical locking, enabling the efficient magnetization switching with a low current density. We demonstrated the current-direction dependent on-off state in TIs-based spin valve devices for memory and logic applications. Further, we demonstrated the Bi2Se3 system will go from a topologically nontrivial state to a topologically trivial state when Bi atoms are replaced by lighter In atoms. Here, topologically trivial metal (BixIny)2 Se3 with high mobility also facilitates the realization of its application in multifunctional spintronic devices.

  4. Low temperature spin dynamics and high pressure effects in frustrated pyrochlores

    Science.gov (United States)

    Mirebeau, Isabelle

    2008-03-01

    Frustrated pyrochlores R2M2O7, where R^3+ is a rare earth and M^4+ a transition or sp metal ion, show a large variety of exotic magnetic states due to the geometrical frustration of the pyrochlore lattice, consisting of corner sharing tetrahedra for both R and M ions. Neutron scattering allows one to measure their magnetic ground state as well as the spin fluctuations, in a microscopic way. An applied pressure may change the subtle energy balance between magnetic interactions, inducing new magnetic states. In this talk, I will review recent neutron results on Terbium pyrochlores, investigated by high pressure neutron diffraction and inelastic neutron scattering. Tb2M2O7 pyrochlores show respectively a spin liquid state for M=Ti [1], an ordered spin ice state for M= Sn [2], and a spin glass state with chemical order for M=Mo [3]. In Tb2Ti2O7 spin liquid, where only Tb^3+ ions are magnetic, an applied pressure induces long range antiferromagnetic order due to a small distortion of the lattice and magneto elastic coupling [4]. In Tb2Sn2O7, the substitution of Ti^4+ by the bigger Sn^4+ ion expands the lattice, inducing a long range ordered ferromagnetic state, with the local structure of a spin ice [2] and unconventional spin fluctuations [2,5]. The local ground state and excited crystal field states of the Tb^3+ ion were recently investigated by inelastic neutron scattering in both compounds [6]. Tb2Mo2O7, where Mo^4+ ions are also magnetic, shows an even more rich behaviour, due to the complex interaction between frustrated Tb and Mo lattices, having respectively localized and itinerant magnetism. In Tb2Mo2O7 spin glass, the lattice expansion induced by Tb/La substitution yields an ordered ferromagnetic state, which transforms back to spin glass under applied pressure [7]. New data about the spin fluctuations in these compounds, as measured by inelastic neutron scattering, will be presented. The talk will be dedicated to the memory of Igor Goncharenko, a renowned

  5. Promising results after percutaneous mitral valve repair

    DEFF Research Database (Denmark)

    Ihlemann, Nikolaj; Franzen, Olaf; Jørgensen, Erik

    2011-01-01

    Mitral valve regurgitation (MR) is the secondmost frequent valve disease in Europe. Untreated MR causes considerable morbidity and mortality. In the elderly, as many as half of these patients are denied surgery because of an estimated high surgical risk. Percutaneous mitral valve repair with the ...... with the MitraClip system resembles the Alfieristitch where a clip is used to connect the tip of the mitral valve leaflets....

  6. Structure of high-spin states in A {approx} 60 region

    Energy Technology Data Exchange (ETDEWEB)

    Nakada, Hitoshi [Chiba Univ. (Japan); Furutaka, K; Hatsukawa, Y [and others

    1998-03-01

    High-spin states in the proton-rich Cu-Zn nuclei are investigated by the experiments at JAERI. New levels and {gamma}-rays are identified by the particle-{gamma}-{gamma} coincidence, and J{sup P} assignments are made via the DCO ratio analysis. Yrast sequences are observed up to J {approx} 18 for {sup 62}Zn, and {sup 64}Zn, J {approx} 27/2 for {sup 61}Cu and J {approx} 23/2 for {sup 63}Cu. Though we cannot settle new J{sup P} values for {sup 61,63}Zn, their yrast sequence is also extended. In {sup 64}Zn, a doublet of {gamma}-rays is discovered at 1315 keV, clarifying the similarity in the level scheme between {sup 62}Zn and {sup 64}Zn. We reproduce the yrast levels by a shell-model calculation, by which structure of the high-spin states is further studied. A parity change in the yrast sequence is established, in which the unique-parity orbit 0g{sub 9/2} plays an essential role; one nucleon excitation to g{sub 9/2} gains high angular momentum with low seniority, at the cost of the single-parity energy. Second parity-change is also suggested by the calculation. Such parity change seems characteristic to spherical or nearly spherical nuclei. In {sup 61}Cu, concentration of the {gamma}-ray intensity is observed. This happens because a stretched 3-quasiparticle configuration including 0g{sub 9/2} is relatively stable, similarly to some isomers. Thus, by studying the structure of the high-spin states of the A {approx} 60 nuclei, we have clarified the role of unique-parity orbit in high-spin states, which may be generic to spherical and nearly spherical nuclei. (J.P.N.)

  7. First observation of high spin states and isomeric decay in 210Fr

    International Nuclear Information System (INIS)

    Kanjilal, D.; Saha, S.; Bhattacharya, S.; Goswami, A.; Kshetri, R.; Raut, R.; Muralithar, S.; Singh, R. P.; Mukherjee, G.; Mukherjee, B.

    2011-01-01

    The first observation of the prompt and the delayed γ transitions involving the high spin states in 210 Fr is reported. The decay of the high spin states and the isomeric levels of 210 Fr, identified for the first time from the known sequence of low-lying transitions found earlier in the α decay of 214 Ac, were studied. High spin states of the doubly-odd 210 Fr, which were produced by the fusion evaporation reaction 197 Au ( 16 O, xn) 213-x Fr, were populated and the subsequent emitted γ rays were detected through the high-sensitivity germanium clover detector array INGA. The level scheme up to yrast levels of 5.3 MeV excitation energy and ∼20(ℎ/2π) angular momentum could be established for the first time through γγ, γγΔT coincidence, and DCO ratio measurements. A new low-lying isomeric transition at E γ = 203(2) keV was observed. The half-life was measured to be T 1/2 = 41(2) ns. The measured half-life was compared with the corresponding single-particle estimate, based on the level scheme obtained from the experiment.

  8. High-spin states in 136La and possible structure change in the N =79 region

    Science.gov (United States)

    Nishibata, H.; Leguillon, R.; Odahara, A.; Shimoda, T.; Petrache, C. M.; Ito, Y.; Takatsu, J.; Tajiri, K.; Hamatani, N.; Yokoyama, R.; Ideguchi, E.; Watanabe, H.; Wakabayashi, Y.; Yoshinaga, K.; Suzuki, T.; Nishimura, S.; Beaumel, D.; Lehaut, G.; Guinet, D.; Desesquelles, P.; Curien, D.; Higashiyama, K.; Yoshinaga, N.

    2015-05-01

    High-spin states in the odd-odd nucleus 136La, which is located close to the β -stability line, have been investigated in the radioactive-beam-induced fusion-evaporation reaction 124Sn(17N,5 n ). The use of the radioactive beam enabled a highly sensitive and successful search for a new isomer [14+,T1 /2=187 (27 ) ns] in 136La. In the A =130 -140 mass region, no such long-lived isomer has been observed at high spin in odd-odd nuclei. The 136La level scheme was revised, incorporating the 14+ isomer and six new levels. The results were compared with pair-truncated shell model (PTSM) calculations which successfully explain the level structure of the π h11 /2⊗ν h11/2 -1 bands in 132La and 134La. The isomerism of the 14+ state was investigated also by a collective model, the cranked Nilsson-Strutinsky (CNS) model, which explains various high-spin structures in the medium-heavy mass region. It is suggested that a new type of collective structure is induced in the PTSM model by the increase of the number of π g7 /2 pairs, and/or in the CNS model by the configuration change associated with the shape change in 136La.

  9. New high spin states and band termination in 83Y and 84Zr

    International Nuclear Information System (INIS)

    Johnson, T.D.; Aprahamian, A.; Lister, C.J.; Blumenthal, D.J.; Crowell, B.; Chowdhury, P.; Fallon, P.; Machiavelli, A.O.

    1997-01-01

    The gamma decay of high spin yrast states in 83 Y up to I π =59/2 + and 53/2 - have been observed using the reaction 58 Ni( 29 Si,3p) at 110 MeV and the Gammasphere Early Implementation Array. The level scheme has been substantially extended due to the observations of several new transitions in all of the bands. A sequence of transitions feeding into the positive parity yrast band above I π =47/2 + seems to be consistent with a noncollective oblate structure expected at these high spins. A similar cascade is found in the data for 84 Zr. A new forking of the favored negative parity band is found which may be due to neutron alignment polarizing the core to a different shape. This suggests that the open-quotes isomeric close-quote close-quote band in 83 Y, for which one more connecting transition was found, is of a similar nature to other high-K bands found in this region. Lifetime measurements in the unfavored negative parity band are consistent with cranking calculations which predict a nearly oblate shape with a deformation parameter β 2 ∼0.2. A qualitative analysis of line shapes at very high spins suggests the persistence of collectivity in the yrast sequence to the highest excitations seen. copyright 1997 The American Physical Society

  10. New high spin states and band termination in {sup 83}Y and {sup 84}Zr

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, T.D.; Aprahamian, A. [University of Notre Dame, Notre Dame, Indiana 46556 (United States); Lister, C.J.; Blumenthal, D.J.; Crowell, B. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Chowdhury, P. [University of Massachusetts, Lowell, Massachusetts 01854 (United States); Fallon, P.; Machiavelli, A.O. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

    1997-03-01

    The gamma decay of high spin yrast states in {sup 83}Y up to I{sup {pi}}=59/2{sup +} and 53/2{sup {minus}} have been observed using the reaction {sup 58}Ni({sup 29}Si,3p) at 110 MeV and the Gammasphere Early Implementation Array. The level scheme has been substantially extended due to the observations of several new transitions in all of the bands. A sequence of transitions feeding into the positive parity yrast band above I{sup {pi}}=47/2{sup +} seems to be consistent with a noncollective oblate structure expected at these high spins. A similar cascade is found in the data for {sup 84}Zr. A new forking of the favored negative parity band is found which may be due to neutron alignment polarizing the core to a different shape. This suggests that the {open_quotes}isomeric{close_quote}{close_quote} band in {sup 83}Y, for which one more connecting transition was found, is of a similar nature to other high-K bands found in this region. Lifetime measurements in the unfavored negative parity band are consistent with cranking calculations which predict a nearly oblate shape with a deformation parameter {beta}{sub 2}{approx}0.2. A qualitative analysis of line shapes at very high spins suggests the persistence of collectivity in the yrast sequence to the highest excitations seen. {copyright} {ital 1997} {ital The American Physical Society}

  11. High spin structure of {sup 35}Cl and the sd-fp shell gap

    Energy Technology Data Exchange (ETDEWEB)

    Kshetri, Ritesh [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata 700064 (India); Saha Sarkar, M. [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata 700064 (India)]. E-mail: maitrayee.sahasarkar@saha.ac.in; Ray, Indrani [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata 700064 (India); Banerjee, P. [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata 700064 (India); Sarkar, S. [Department of Physics, Bengal Engineering and Science University, Shibpur, Howrah 711103 (India); Raut, Rajarshi [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata 700064 (India); Goswami, A. [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata 700064 (India); Chatterjee, J.M. [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata 700064 (India); Chattopadhyay, S. [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata 700064 (India); Datta Pramanik, U. [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata 700064 (India); Mukherjee, A. [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata 700064 (India); Dey, C.C. [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata 700064 (India); Bhattacharya, S. [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata 700064 (India); Dasmahapatra, B. [Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata 700064 (India); Bhowal, Samit [Department of Physics, Surendranath Evening College, Kolkata 700009 (India); Gangopadhyay, G. [University of Calcutta, 92, Acharya Prafulla Chandra Road, Kolkata 700009 (India); Datta, P. [Anandamohan College, 102/1, Raja Rammohan Sarani, Kolkata 700009 (India); Jain, H.C. [Tata Institute of Fundamental Research, Mumbai 400005 (India); Bhowmik, R.K. [Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India); Muralithar, S.; Singh, R.P.; Kumar, R. [Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India)

    2007-01-15

    The high spin states of {sup 35}Cl have been studied by in-beam {gamma}-spectroscopy following the fusion-evaporation reaction {sup 12}C({sup 28}Si,{alpha}p){sup 35}Cl at E{sub lab}=70 and 88 MeV, using the Indian National Gamma (Clover) Array (INGA). Lifetimes of six new excited states have been estimated for the first time. To understand the underlying structure of the levels and transition mechanisms, experimental results have been compared with those from the large basis cross-shell shell model calculations. Involvement of orbitals from fp shell and squeezing of the sd-fp shell gap seem to be essential for reliable reproduction of high spin states.

  12. High spin structure of 35Cl and the sd-fp shell gap

    International Nuclear Information System (INIS)

    Kshetri, Ritesh; Saha Sarkar, M.; Ray, Indrani; Banerjee, P.; Sarkar, S.; Raut, Rajarshi; Goswami, A.; Chatterjee, J.M.; Chattopadhyay, S.; Datta Pramanik, U.; Mukherjee, A.; Dey, C.C.; Bhattacharya, S.; Dasmahapatra, B.; Bhowal, Samit; Gangopadhyay, G.; Datta, P.; Jain, H.C.; Bhowmik, R.K.; Muralithar, S.; Singh, R.P.; Kumar, R.

    2007-01-01

    The high spin states of 35 Cl have been studied by in-beam γ-spectroscopy following the fusion-evaporation reaction 12 C( 28 Si,αp) 35 Cl at E lab =70 and 88 MeV, using the Indian National Gamma (Clover) Array (INGA). Lifetimes of six new excited states have been estimated for the first time. To understand the underlying structure of the levels and transition mechanisms, experimental results have been compared with those from the large basis cross-shell shell model calculations. Involvement of orbitals from fp shell and squeezing of the sd-fp shell gap seem to be essential for reliable reproduction of high spin states

  13. High-spin states in the A=39 mirror nuclei 39Ca and 39K

    International Nuclear Information System (INIS)

    Andersson, T.; Rudolph, D.; Fahlander, C.; Eberth, J.; Thomas, H.G.; Haslip, D.; Svensson, C.E.; Waddington, J.C.; LaFosse, D.R.; Sarantites, D.G.; Weintraub, W.; Wilson, J.N.; Brown, B.A.

    1999-01-01

    High-spin states of the mass A=39 mirror pair 39 K and 39 Ca were investigated via the fusion-evaporation reaction 28 Si+ 16 O at 125 MeV beam energy. The gammasphere array in conjunction with the 4π charged-particle detector array microball and neutron detectors was used to detect γ rays in coincidence with evaporated light particles. The results of the first high-spin study of the T z =-1/2 nucleus 39 Ca are discussed in terms of mirror symmetry and compared to spherical shell-model calculations in the 1d 3/2 -1f 7/2 configuration space. (orig.)

  14. High-spin lifetime measurements in the N=Z nucleus Kr72

    Science.gov (United States)

    Andreoiu, C.; Svensson, C. E.; Afanasjev, A. V.; Austin, R. A. E.; Carpenter, M. P.; Dashdorj, D.; Finlay, P.; Freeman, S. J.; Garrett, P. E.; Greene, J.; Grinyer, G. F.; Görgen, A.; Hyland, B.; Jenkins, D.; Johnston-Theasby, F.; Joshi, P.; Machiavelli, A. O.; Moore, F.; Mukherjee, G.; Phillips, A. A.; Reviol, W.; Sarantites, D. G.; Schumaker, M. A.; Seweryniak, D.; Smith, M. B.; Valiente-Dobón, J. J.; Wadsworth, R.

    2007-04-01

    High-spin states in the N=Z nucleus Kr72 have been populated in the Ca40(Ca40, 2α)Kr72 fusion-evaporation reaction at a beam energy of 165 MeV using the Gammasphere array for γ-ray detection coupled to the Microball array for charged particle detection. The previously observed bands in Kr72 were extended to an excitation energy of ˜24 MeV and angular momentum of 30ℏ. Using the Doppler shift attenuation method the lifetimes of high-spin states were measured for the first time. Excellent agreement between the results of calculations within the isovector mean field theory and experiment is observed both for rotational and deformation properties. No enhancement of quadrupole deformation expected in the presence of isoscalar t=0 np pairing is observed. Current data do not show any evidence for the existence of the isoscalar np pairing.

  15. A high-spin and durable polyradical: poly(4-diphenylaminium-1,2-phenylenevinylene).

    Science.gov (United States)

    Murata, Hidenori; Takahashi, Masahiro; Namba, Kazuaki; Takahashi, Naoki; Nishide, Hiroyuki

    2004-02-06

    A purely organic, high-spin, and durable polyradical molecule was synthesized: It is based on the non-Kekulé- and non-disjoint design of a pi-conjugated poly(1,2-phenylenevinylene) backbone pendantly 4-substituted with multiple robust arylaminium radicals. 4-N,N-Bis(4-methoxy- and -tert-butylphenyl)amino-2-bromostyrene 5 were synthesized and polymerized with a palladium-phosphine catalyst to afford the head-to-tail-linked polyradical precursors (1). Oxidation of 1 with the nitrosonium ion solubilized with a crown ether gave the aminium polyradicals (1(+)()) which were durable (half-life > 1 month) at room temperature in air. A high-spin ground state with an average S = (4.5)/2 for 1a(+) was proved even at room temperature by magnetic susceptibility, magnetization, ESR, and NMR measurements.

  16. Equation-of-motion coupled cluster method for high spin double electron attachment calculations

    Energy Technology Data Exchange (ETDEWEB)

    Musiał, Monika, E-mail: musial@ich.us.edu.pl; Lupa, Łukasz; Kucharski, Stanisław A. [Institute of Chemistry, University of Silesia, Szkolna 9, 40-006 Katowice (Poland)

    2014-03-21

    The new formulation of the equation-of-motion (EOM) coupled cluster (CC) approach applicable to the calculations of the double electron attachment (DEA) states for the high spin components is proposed. The new EOM equations are derived for the high spin triplet and quintet states. In both cases the new equations are easier to solve but the substantial simplification is observed in the case of quintets. Out of 21 diagrammatic terms contributing to the standard DEA-EOM-CCSDT equations for the R{sub 2} and R{sub 3} amplitudes only four terms survive contributing to the R{sub 3} part. The implemented method has been applied to the calculations of the excited states (singlets, triplets, and quintets) energies of the carbon and silicon atoms and potential energy curves for selected states of the Na{sub 2} (triplets) and B{sub 2} (quintets) molecules.

  17. Constructing binary black hole initial data with high mass ratios and spins

    Science.gov (United States)

    Ossokine, Serguei; Foucart, Francois; Pfeiffer, Harald; Szilagyi, Bela; Simulating Extreme Spacetimes Collaboration

    2015-04-01

    Binary black hole systems have now been successfully modelled in full numerical relativity by many groups. In order to explore high-mass-ratio (larger than 1:10), high-spin systems (above 0.9 of the maximal BH spin), we revisit the initial-data problem for binary black holes. The initial-data solver in the Spectral Einstein Code (SpEC) was not able to solve for such initial data reliably and robustly. I will present recent improvements to this solver, among them adaptive mesh refinement and control of motion of the center of mass of the binary, and will discuss the much larger region of parameter space this code can now address.

  18. Spin transport in nanowires

    OpenAIRE

    Pramanik, S.; bandyopadhyay, S.; Cahay, M.

    2003-01-01

    We study high-field spin transport of electrons in a quasi one-dimensional channel of a $GaAs$ gate controlled spin interferometer (SPINFET) using a semiclassical formalism (spin density matrix evolution coupled with Boltzmann transport equation). Spin dephasing (or depolarization) is predominantly caused by D'yakonov-Perel' relaxation associated with momentum dependent spin orbit coupling effects that arise due to bulk inversion asymmetry (Dresselhaus spin orbit coupling) and structural inve...

  19. Fabrication of high strength PVA/SWCNT composite fibers by gel spinning

    OpenAIRE

    Xu, Xuezhu; Uddin, Ahmed Jalal; Aoki, Kenta; Gotoh, Yasuo; Saito, Takeshi; Yumura, Motoo

    2010-01-01

    High-strength composite fibers were prepared from polyvinyl alcohol (PVA) (Degree of polymerization: 1500) reinforced by single-walled carbon nanotubes (SWCNTs) containing few defects. The SWCNTs were dispersed in a 10 wt.% PVA/dimethylsulfoxide solution using a mechanical homogenizer that reduced the size of SWCNT aggregations to smaller bundles. The macroscopically homogeneous dispersion was extruded into cold methanol to form fibers by gel spinning followed by a hot-drawing. The tensile st...

  20. High-Spin States in Odd-Odd N=Z {sup 46}V

    Energy Technology Data Exchange (ETDEWEB)

    O' Leary, C.D.; Bentley, M.A.; Appelbe, D.E.; Bark, R.A.; Cullen, D.M.; Erturk, S.; Maj. A.; Sheikh, J.A.; Warner, D.D.

    1999-12-31

    High-spin states up to the F{sub 7/2}-shell band termination at J{pi}=15+ have been observed for the first time in the odd-odd N=Z=23 nucleous {sup 46}V. The new level scheme has two separate structures corresponding to spherical and prolate shapes. A rotational band has very similar energies to the yrast sequence in {sup 46}Ti and is therefore assumed to be a T=1 configuration.