WorldWideScience

Sample records for major axis perpendicular

  1. Major and minor axis kinematics of 22 ellipticals

    International Nuclear Information System (INIS)

    Franx, M.; Illingworth, G.; Heckman, T.

    1989-01-01

    Rotation curves and velocity dispersion profiles have been determined for the major and the minor axes of 22 elliptical galaxies. Rotation was detected in all but one galaxy, even though the sample was biased toward round ellipticals. Minor axis rotation larger than major axis rotation was measured in two galaxies, NGC 4406 and NGC 7507. Roughly 10 percent of ellipticals may show large minor axis velocities relative to those on the major axis. A simple model is used to derive a rotational axis from the observed minor and major axis velocities to a typical accuracy of 6 deg. The rotational and photometric minor axes aligned to better than 10 deg for 60 percent of the sample, implying that the direction of the angular momentum is related to the orientation of the figure of the galaxy. IC 1459 has a kinematically distinct core with its angular momentum opposite to the angular momentum of the outer parts, and NGC 4406 has a core with its angular momentum perpendicular to that of the outer parts. 46 refs

  2. Anisotropic perpendicular axis magnetostriction in twinned TbxDy1-xFe1.95

    International Nuclear Information System (INIS)

    Teter, J.P.; Wun-Fogle, M.; Clark, A.E.; Mahoney, K.

    1990-01-01

    The longitudinal magnetostriction (Δl/l) for twinned Tb x Dy 1-x Fe 1.95 material, prepared by the free-standing float-zone method, has been previously measured and found to be very large (2000x10 -6 ) at room temperature. The magnetostrictions for the [111] and [1 bar 10] crystallographic axes perpendicular to the applied stress and magnetic-field [11 bar 2] direction are presented as functions of temperature, applied stress, and applied magnetic field. The temperature range is ±60 degree C centered about the anisotropy compensation temperature of Terfenol-D (+10 degree C). The stress ranges from 2 to 32 MPa and the magnetic field to ±2000 Oe. The temperature dependence of the perpendicular axes magnetostriction is similar to that of the conventional magnetostriction measured parallel to the [11 bar 2] growth axis. Relative values for the saturation magnetostriction exhibit a large anisotropy in the perpendicular direction, ranging from -117% for the [111] to +19% for the [1 bar 10] direction. This ratio stays constant as a function of temperature above the compensation temperature for a given prestress above 8 MPa. The largest absolute value of magnetostriction (2260x10 -6 ) occurs in the [111] direction at 10 degree C at a prestress pressure of 12 MPa. Above this temperature the magnetostriction falls at a rate of -8.5x10 -6 /degree C. The volume magnetostriction is shown to be small and highly sample dependent. All data is consistent with the parent-twin magnetization model and also the magnetostriction values along nonprincipal axes

  3. Enhancement of L10 ordering with the c-axis perpendicular to the substrate in FePt alloy film by using an epitaxial cap-layer

    Directory of Open Access Journals (Sweden)

    Mitsuru Ohtake

    2017-05-01

    Full Text Available FePt alloy thin films with cap-layers of MgO or C are prepared on MgO(001 single-crystal substrates by using a two-step method consisting of low-temperature deposition at 200 °C followed by high-temperature annealing at 600 °C. The FePt film thickness is fixed at 10 nm, whereas the cap-layer thickness is varied from 1 to 10 nm. The influences of cap-layer material and cap-layer thickness on the variant structure and the L10 ordering are investigated. Single-crystal FePt(001 films with disordered fcc structure (A1 grow epitaxially on the substrates at 200 °C. Single-crystal MgO(001 cap-layers grow epitaxially on the FePt films, whereas the structure of C cap-layers is amorphous. The phase transformation from A1 to L10 occurs when the films are annealed at 600 °C. The FePt films with MgO cap-layers thicker than 2 nm consist of L10(001 variant with the c-axis perpendicular to the substrate surface, whereas those with C cap-layers involve small volumes of L10(100 and (010 variants with the c-axis lying in the film plane. The in-plane and the out-of-plane lattices are respectively more expanded and contracted in the continuous-lattice MgO/FePt/MgO structure due to accommodations of misfits of FePt film with respect to not only the MgO substrate but also the MgO cap-layer. The lattice deformation promotes phase transformation along the perpendicular direction and L10 ordering. The FePt films consisting of only L10(001 variant show strong perpendicular magnetic anisotropies and low in-plane coercivities. The present study shows that an introduction of epitaxial cap-layer is effective in controlling the c-axis perpendicular to the substrate surface.

  4. Light scattering of rectangular slot antennas: parallel magnetic vector vs perpendicular electric vector

    Science.gov (United States)

    Lee, Dukhyung; Kim, Dai-Sik

    2016-01-01

    We study light scattering off rectangular slot nano antennas on a metal film varying incident polarization and incident angle, to examine which field vector of light is more important: electric vector perpendicular to, versus magnetic vector parallel to the long axis of the rectangle. While vector Babinet’s principle would prefer magnetic field along the long axis for optimizing slot antenna function, convention and intuition most often refer to the electric field perpendicular to it. Here, we demonstrate experimentally that in accordance with vector Babinet’s principle, the incident magnetic vector parallel to the long axis is the dominant component, with the perpendicular incident electric field making a small contribution of the factor of 1/|ε|, the reciprocal of the absolute value of the dielectric constant of the metal, owing to the non-perfectness of metals at optical frequencies.

  5. An analytical calculation of the peak efficiency for cylindrical sources perpendicular to the detector axis in gamma-ray spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, Julio C. [Autoridad Regulatoria Nuclear, Laboratorio de Espectrometria Gamma-CTBTO, Av. Del Libertador 8250, C1429BNP Buenos Aires (Argentina)], E-mail: jaguiar@sede.arn.gov.ar

    2008-08-15

    An analytical expression for the so-called full-energy peak efficiency {epsilon}(E) for cylindrical source with perpendicular axis to an HPGe detector is derived, using point-source measurements. The formula covers different measuring distances, matrix compositions, densities and gamma-ray energies; the only assumption is that the radioactivity is homogeneously distributed within the source. The term for the photon self-attenuation is included in the calculation. Measurements were made using three different sized cylindrical sources of {sup 241}Am, {sup 57}Co, {sup 137}Cs, {sup 54}Mn, and {sup 60}Co with corresponding peaks of 59.5, 122, 662, 835, 1173, and 1332 keV, respectively, and one measurement of radioactive waste drum for 662, 1173, and 1332 keV.

  6. Fragmentation of a Filamentary Cloud Permeated by a Perpendicular Magnetic Field

    Energy Technology Data Exchange (ETDEWEB)

    Hanawa, Tomoyuki [Center for Frontier Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba, Chiba 263-8522 (Japan); Kudoh, Takahiro [Faculty of Education, Nagasaki University, 1-14 Bonkyo-machi, Nagasaki, Nagasaki 852-8521 (Japan); Tomisaka, Kohji [Division of Theoretical Astronomy, National Astronomical Observatory of Japan, Mitaka, Tokyo 181-8588 (Japan)

    2017-10-10

    We examine the linear stability of an isothermal filamentary cloud permeated by a perpendicular magnetic field. Our model cloud is assumed to be supported by gas pressure against self-gravity in the unperturbed state. For simplicity, the density distribution is assumed to be symmetric around the axis. Also for simplicity, the initial magnetic field is assumed to be uniform, and turbulence is not taken into account. The perturbation equation is formulated to be an eigenvalue problem. The growth rate is obtained as a function of the wavenumber for fragmentation along the axis and the magnetic field strength. The growth rate depends critically on the outer boundary. If the displacement vanishes in regions very far from the cloud axis (fixed boundary), cloud fragmentation is suppressed by a moderate magnetic field, which means the plasma beta is below 1.67 on the cloud axis. If the displacement is constant along the magnetic field in regions very far from the cloud, the cloud is unstable even when the magnetic field is infinitely strong. The cloud is deformed by circulation in the plane perpendicular to the magnetic field. The unstable mode is not likely to induce dynamical collapse, since it is excited even when the whole cloud is magnetically subcritical. For both boundary conditions, the magnetic field increases the wavelength of the most unstable mode. We find that the magnetic force suppresses compression perpendicular to the magnetic field especially in regions of low density.

  7. Imaging chemical interfaces perpendicular to the optical axis with focus-engineered coherent anti-Stokes Raman scattering microscopy

    International Nuclear Information System (INIS)

    Krishnamachari, Vishnu Vardhan; Potma, Eric Olaf

    2007-01-01

    In vibrational microscopy, it is often necessary to distinguish between chemically distinct microscopic objects and to highlight the 'chemical interfaces' present in the sample under investigation. Here we apply the concept of focus engineering to enhance the sensitivity of coherent anti-Stokes Raman scattering (CARS) microscopy to these interfaces. Based on detailed numerical simulations, we show that using a focused Stokes field with a sharp phase jump along the longitudinal direction leads to the suppression of the signal from bulk regions and improves the signal contrast from vibrational resonant interfaces oriented perpendicular to the axis of beam propagation. We also demonstrate that the CARS spectral response from chemical interfaces exhibits a clean, Raman-like band-shape with such a phase-shaped excitation. This phenomenon of interface highlighting is a consequence of the coherent nature of CARS signal generation and it involves a complex interplay of the spectral phase of the sample and the spatial phase of the excitation fields

  8. Perpendicular magnetic tunnel junction with a strained Mn-based nanolayer

    Science.gov (United States)

    Suzuki, K. Z.; Ranjbar, R.; Okabayashi, J.; Miura, Y.; Sugihara, A.; Tsuchiura, H.; Mizukami, S.

    2016-07-01

    A magnetic tunnel junction with a perpendicular magnetic easy-axis (p-MTJ) is a key device for spintronic non-volatile magnetoresistive random access memory (MRAM). Co-Fe-B alloy-based p-MTJs are being developed, although they have a large magnetisation and medium perpendicular magnetic anisotropy (PMA), which make it difficult to apply them to a future dense MRAM. Here, we demonstrate a p-MTJ with an epitaxially strained MnGa nanolayer grown on a unique CoGa buffer material, which exhibits a large PMA of more than 5 Merg/cm3 and magnetisation below 500 emu/cm3 these properties are sufficient for application to advanced MRAM. Although the experimental tunnel magnetoresistance (TMR) ratio is still low, first principles calculations confirm that the strain-induced crystal lattice distortion modifies the band dispersion along the tetragonal c-axis into the fully spin-polarised state; thus, a huge TMR effect can be generated in this p-MTJ.

  9. NANO-MULTILAYERS WITH HIGH PERPENDICULAR ANISOTROPY FOR MAGNETIC RECORDING

    Institute of Scientific and Technical Information of China (English)

    T. Yang; B.H. Li; K. Kang; T. Suzuki

    2003-01-01

    (FePt/Ag)n nano-multilayers were deposited on MgO (100) single crystal with laser ablation and then subjected to annealing. FePt L1o grains with (001) texture and thus a large perpendicular magnetic anisotropy constant Ku of the order of 106J/m3 were formed. A thick Ag layer is found to be favorable for decreasing the dispersion of the easy axis for magnetization. The measurement of time decay of magnetization gave rise to a small activation volume of the order of 10-25 m3, showing the promising of being the recording medium for future high density perpendicular recording.

  10. Perpendicular biased ferrite tuned RF cavity for the TRIUMF KAON Factory booster ring

    International Nuclear Information System (INIS)

    Poirier, R.L.; Enegren, T.; Haddock, C.

    1989-03-01

    The rf cavity for the booster ring requires a frequency swing of 46 MHz to 62 MHz at a repetition rate of 50 Hz. The possibility of using the LANL booster cavity design with a yttrium garnet ferrite tuner biased perpendicular to the rf field, in the longitudinal direction, is being investigated. In order to minimize the stray magnetic biasing field on the beam axis, an alternative scheme similar to the design being proposed for the LANL main ring cavity in which the ferrite is perpendicular biased in the radial direction, is being considered. The behaviour of the rf cavity and the magnetizing circuit for both designs are discussed

  11. Preparation of c-axis perpendicularly oriented ultra-thin L10-FePt films on MgO and VN underlayers

    Science.gov (United States)

    Futamoto, Masaaki; Shimizu, Tomoki; Ohtake, Mitsuru

    2018-05-01

    Ultra-thin L10-FePt films of 2 nm average thickness are prepared on (001) oriented MgO and VN underlayers epitaxially grown on base substrate of SrTiO3(001) single crystal. Detailed cross-sectional structures are observed by high-resolution transmission electron microscopy. Continuous L10-FePt(001) thin films with very flat surface are prepared on VN(001) underlayer whereas the films prepared on MgO(001) underlayer consist of isolated L10-FePt(001) crystal islands. Presence of misfit dislocation and lattice bending in L10-FePt material is reducing the effective lattice mismatch with respect to the underlayer to be less than 0.5 %. Formation of very flat and continuous FePt layer on VN underlayer is due to the large surface energy of VN material where de-wetting of FePt material at high temperature annealing process is suppressed under a force balance between the surface and interface energies of FePt and VN materials. An employment of underlayer or substrate material with the lattice constant and the surface energy larger than those of L10-FePt is important for the preparation of very thin FePt epitaxial thin continuous film with the c-axis controlled to be perpendicular to the substrate surface.

  12. [Localization and registration of the hinge axis in black Africans].

    Science.gov (United States)

    Assi, K D; N'Guessan, K S; N'Dindin, C; Bamba, A

    2003-06-01

    The study of the cinematic method using "SAM" and "Quick Axis of FAG" added to mandibular condyle palpation for the hinge axis limited points, show that the Black Africans mandibular condyle rotation axis position is higher (3.5 mm) and backer (2 mm) than the Caucasians. The axial points are located to between 11 and 12 mm in front of the tragus and between 7 and 8 mm below on the perpendicular line to the furrow defining the tragus superior side to the Ectocanthus.

  13. Intermediate layer thickness dependence on switching field distribution in perpendicular recording media

    International Nuclear Information System (INIS)

    Sbiaa, R.; Gandhi, R.; Srinivasan, K.; Piramanayagam, S.N.; Seoh, R.M.

    2009-01-01

    The effect of intermediate layer (IL) thickness on crystallographic texture and magnetic properties of CoCrPtSiO 2 granular perpendicular recording media was investigated with switching field distribution (SFD) as the focus. Even though the c-axis orientation of the Co-based recording layer (RL) broadens with the reduction of IL thickness, the SFD becomes narrower. This result demonstrates that the intrinsic SFD is not directly dependent on c-axis orientation of the recording layer but instead dependent on the magnitude of exchange coupling. It is thus possible to have a medium with thin IL and narrow SFD. This is desirable for bit-patterned media (BPM), where highly exchange-coupled grains are required.

  14. The hypothalamo-pituitary-adrenal axis in major affective disorder

    DEFF Research Database (Denmark)

    Christensen, M V; Kessing, L V

    2001-01-01

    disorder. The HPA axis is a complex neuroendocrine network with multiple integrated levels of control, and it is likely that the dysregulation involves abnormalities at several sites within the axis. At present, it is not clear whether the abnormalities are related to the affective episodes only......This paper reviews studies of the hypothalamo-pituitary-adrenal (HPA)-axis activity in patients with affective disorders. It is concluded that, despite methodological drawbacks in most studies, dysregulation of the HPA axis seems to be a consistent finding in a proportion of patients with affective...... or to the disorder itself. There is a need for prospective studies of larger samples of patients to be followed during successive affective episodes with a combination of measurements of the HPA-axis activity and brain imaging....

  15. Design Of Single-Axis And Dual-Axis Solar Tracking Systems Protected Against High Wind Speeds

    Directory of Open Access Journals (Sweden)

    Mai Salaheldin Elsherbiny

    2017-09-01

    Full Text Available Solar energy is rapidly gaining ground as an important mean of expanding renewable energy use. Solar tracking is employed in order to maximize collected solar radiation by a photovoltaic panel. In this paper we present a prototype for Automatic solar tracker that is designed using Arduino UNO with Wind sensor to Cease Wind effect on panels if wind speed exceeds certain threshold. The Proposed solar tracker tracks the location of the sun anywhere in any time by calculating the position of the sun. For producing the maximum amount of solar energy a solar panel must always be perpendicular to the source of light. Because the sun motion plane varies daily and during the day it moves from east to west one needs two axis tracking to follow the suns position. Maximum possible power is collected when two axis tracking is done. However two axis tracking is relatively costly and complex. A compromise between maximum power collection and system simplicity is obtained by single axis tracking where the plane North south axis is fixed while the east west motion is accomplished. This work deals with the design of both single and two axis tracking systems. Automatic trackers is also compared to Fixed one in terms of Energy generated Efficiency Cost and System reliability.

  16. Shot H3837: Darht's First Dual-Axis Explosive Experiment

    Science.gov (United States)

    Mendez, Jacob; McNeil, Wendy Vogan; Harsh, James; Hull, Lawrence

    2011-06-01

    Test H3837 was the first explosive shot performed in front of both flash x-ray axes at the Los Alamos Dual Axis Radiographic HydroTest (DARHT) facility. Executed in November 2009, the shot was an explosively-driven metal flyer plate in a series of experiments designed to explore equation-of-state properties of shocked materials. Imaging the initial shock wave traveling through the flyer plate, DARHT Axis II captured the range of motion from the shock front emergence in the flyer to breakout at the free surface; the Axis I pulse provided a perpendicular perspective of the shot at a time coinciding with the third pulse of Axis II. Since the days of the Manhattan Project, penetrating radiography with multiple frames from different viewing angles has remained a high-profile goal at the Laboratory. H3837 is merely the beginning of a bright future for two-axis penetrating radiography.

  17. Perpendicular magnetic recording-Its development and realization

    Energy Technology Data Exchange (ETDEWEB)

    Iwasaki, Shun-ichi, E-mail: iwasaki@tohtech.ac.jp [Tohoku Institute of Technology, 35-1 Yagiyamakasumi-cho, Taihaku-ku, Sendai 982-8577 (Japan)

    2012-02-15

    Development of perpendicular magnetic recording is summarized along with learning from the research study. The early stage of perpendicular recording was conducted with the research philosophy of complementarity between perpendicular and horizontal recordings. Although present production of the perpendicular recording HDDs exceeds 600 million per year, development of perpendicular recording experienced the valley of death in the 1990s. The difficult period was overcome by the collaboration system of industrial and academic communities. The research on perpendicular recording brought about development of new research model as well as the historical view of the development of technology and innovation. The huge influence of perpendicular recording on society also taught us the relationship between science and technology with culture and civilization. - Research Highlights: > Discovery of circular magnetization led to idea of perpendicular recording. > SPT head and Co-Cr media were realized for practical perpendicular recording. > The complementarity between perpendicular and in-plane recording helped progress. > Death valley of research has been overcome by cooperation with potent companies. > Present mass production of HDDs is making a new civilization of the society.

  18. Weak-field precession of nano-pillar spin-torque oscillators using MgO-based perpendicular magnetic tunnel junction

    Science.gov (United States)

    Zhang, Changxin; Fang, Bin; Wang, Bochong; Zeng, Zhongming

    2018-04-01

    This paper presents a steady auto-oscillation in a spin-torque oscillator using MgO-based magnetic tunnel junction (MTJ) with a perpendicular polarizer and a perpendicular free layer. As the injected d.c. current varied from 1.5 to 3.0 mA under a weak magnetic field of 290 Oe, the oscillation frequency decreased from 1.85 to 1.3 GHz, and the integrated power increased from 0.1 to 74 pW. A narrow linewidth down to 7 MHz corresponding to a high Q factor of 220 was achieved at 2.7 mA, which was ascribed to the spatial coherent procession of the free layer magnetization. Moreover, the oscillation frequency was quite sensitive to the applied field, about 3.07 MHz/Oe, indicating the potential applications as a weak magnetic field detector. These results suggested that the MgO-based MTJ with perpendicular magnetic easy axis could be helpful for developing spin-torque oscillators with narrow-linewidth and high sensitive.

  19. Dual axis translation apparatus and system for translating an optical beam and related method

    Science.gov (United States)

    Cassidy, Kelly

    1991-01-01

    A dual axis translation device and system in accordance with this invention, for translating an optical beam along both an x-axis and a y-axis which are perpendicular to one another, has a beam directing means acting on said optical beam for directing the beam along a particular path transverse to said x and y axes. An arrangement supporting said beam directing means for movement in the x and y direction within a given plane is provided. The arrangement includes a first means for translating said beam directing means along the x-axis in said given plane in order to translate the beam along said x-axis. The arrangement comprises a second means for translating said beam directing means along the y-axis in said given plane in order to translate the beam along said y-axis.

  20. Multilocus phylogeny, divergence times, and a major role for the benthic-to-pelagic axis in the diversification of grunts (Haemulidae).

    Science.gov (United States)

    Tavera, Jose; Acero P, Arturo; Wainwright, Peter C

    2018-04-01

    We present a phylogenetic analysis with divergence time estimates, and an ecomorphological assessment of the role of the benthic-to-pelagic axis of diversification in the history of haemulid fishes. Phylogenetic analyses were performed on 97 grunt species based on sequence data collected from seven loci. Divergence time estimation indicates that Haemulidae originated during the mid Eocene (54.7-42.3 Ma) but that the major lineages were formed during the mid-Oligocene 30-25 Ma. We propose a new classification that reflects the phylogenetic history of grunts. Overall the pattern of morphological and functional diversification in grunts appears to be strongly linked with feeding ecology. Feeding traits and the first principal component of body shape strongly separate species that feed in benthic and pelagic habitats. The benthic-to-pelagic axis has been the major axis of ecomorphological diversification in this important group of tropical shoreline fishes, with about 13 transitions between feeding habitats that have had major consequences for head and body morphology. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. An additional reference axis improves femoral rotation alignment in image-free computer navigation assisted total knee arthroplasty.

    Science.gov (United States)

    Inui, Hiroshi; Taketomi, Shuji; Nakamura, Kensuke; Sanada, Takaki; Tanaka, Sakae; Nakagawa, Takumi

    2013-05-01

    Few studies have demonstrated improvement in accuracy of rotational alignment using image-free navigation systems mainly due to the inconsistent registration of anatomical landmarks. We have used an image-free navigation for total knee arthroplasty, which adopts the average algorithm between two reference axes (transepicondylar axis and axis perpendicular to the Whiteside axis) for femoral component rotation control. We hypothesized that addition of another axis (condylar twisting axis measured on a preoperative radiograph) would improve the accuracy. One group using the average algorithm (double-axis group) was compared with the other group using another axis to confirm the accuracy of the average algorithm (triple-axis group). Femoral components were more accurately implanted for rotational alignment in the triple-axis group (ideal: triple-axis group 100%, double-axis group 82%, P<0.05). Copyright © 2013 Elsevier Inc. All rights reserved.

  2. Crystallization and preliminary X-ray analysis of Leishmania major glyoxalase I

    Energy Technology Data Exchange (ETDEWEB)

    Ariza, Antonio; Vickers, Tim J.; Greig, Neil; Fairlamb, Alan H.; Bond, Charles S., E-mail: c.s.bond@dundee.ac.uk [Division of Biological Chemistry and Molecular Microbiology, Wellcome Trust Biocentre, School of Life Sciences, University of Dundee, Dundee DD1 5EH,Scotland (United Kingdom)

    2005-08-01

    The detoxification enzyme glyoxalase I from L. major has been crystallized. Preliminary molecular-replacement calculations indicate the presence of three glyoxalase I dimers in the asymmetric unit. Glyoxalase I (GLO1) is a putative drug target for trypanosomatids, which are pathogenic protozoa that include the causative agents of leishmaniasis. Significant sequence and functional differences between Leishmania major and human GLO1 suggest that it may make a suitable template for rational inhibitor design. L. major GLO1 was crystallized in two forms: the first is extremely disordered and does not diffract, while the second, an orthorhombic form, produces diffraction to 2.0 Å. Molecular-replacement calculations indicate that there are three GLO1 dimers in the asymmetric unit, which take up a helical arrangement with their molecular dyads arranged approximately perpendicular to the c axis. Further analysis of these data are under way.

  3. A method of producing small grain Ru intermediate layers for perpendicular magnetic media

    International Nuclear Information System (INIS)

    Yuan Hua; Qin Yueling; Laughlin, David E.

    2008-01-01

    NiAl + SiO 2 thin films were used as a grain size reducing seedlayer for cobalt alloy granular perpendicular magnetic recording media. The effect of this NiAl + SiO 2 seedlayer on the microstructure and crystalline orientation of Ru intermediate layer has been investigated. By co-sputtering the composite NiAl + SiO 2 seedlayer, the smallest average grain diameter of NiAl was significantly reduced to about 2.5 nm. The grain size of the subsequent Ru intermediate layer was reduced to about 4 nm. X-ray diffraction results indicate an epitaxial orientation relationship of NiAl (110) // Ru (0002) between the two layers. Moreover, significant improvement of this epitaxial relationship was developed, which produced narrow c-axis distribution of the Ru intermediate layer with small grain size. The addition of the NiAl + SiO 2 seedlayer is a very promising approach to reduce the Ru intermediate layer grain size and eventually the magnetic layer grain size for perpendicular magnetic recording media without deterioration of other properties of thin films

  4. Magnetic and structural properties of L1{sub 1} type CoPt-C ordered alloy perpendicular films as a function of C content

    Energy Technology Data Exchange (ETDEWEB)

    Shimatsu, T; Kataoka, H; Aoi, H [Research Institute of Electrical Communication, Tohoku University, Sendai, 980-8577 (Japan); Sato, H; Okamoto, S; Kitakami, O, E-mail: shimatsu@riec.tohoku.ac.j [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai, 980-8577 (Japan)

    2010-01-01

    Magnetic and structural properties of L1{sub 1} type (Co{sub 0.5}Pt{sub 0.5}){sub 100-X}-C{sub X} ordered alloy perpendicular films, fabricated on 2.5 inch size glass disks by sputter deposition, were examined as a function of C content, X. L1{sub 1} type Co{sub 0.5}Pt{sub 0.5}-C polycrystalline films (10 nm thickness), with <111> axis (the easy axis) perpendicular to the film plane, were successfully fabricated even for a 30 vol% C content. Structural analysis indicated the segregation of C to the grain boundaries. Uniaxial magnetic anisotropy, K{sub u}, of Co{sub 0.5}Pt{sub 0.5} films without C addition was relatively low, about 1.5x10{sup 7} erg/cm{sup 3} under the present deposition conditions. However, the addition of 5 vol.% C to Co-Pt films enhanced the ordering, resulting in an increase in K{sub u} to around 2.5 x10{sup 7} erg/cm{sup 3}. A further increase in C content reduced K{sub u}; however, K{sub u} maintained a relatively large value of about 1.8x10{sup 7} erg/cm{sup 3} even for a 20vol% C content, without degrading the easy axis orientation perpendicular to the film plane. Experimental results demonstrated the potential of the L1{sub 1} type Co{sub 0.5}Pt{sub 0.5}-C films for use in granular media applications, due to their very high K{sub u}, the relatively low fabrication temperature, and good controllability of the grain orientation.

  5. Diurnal Hypothalamic-Pituitary-Adrenal Axis Measures and Inflammatory Marker Correlates in Major Depressive Disorder

    Directory of Open Access Journals (Sweden)

    Kelly Doolin

    2017-10-01

    Full Text Available Dysregulation of the hypothalamic-pituitary-adrenal (HPA axis and inflammatory systems is a consistent finding in patients with Major Depressive Disorder (MDD. Cortisol is often assessed by measurement of the cortisol awakening response (CAR and/or diurnal cortisol levels. Some methods of cortisol measurement overestimate cortisol concentration due to detection of other glucocorticoids including the relatively inert cortisone, therefore this study aimed to assess the presence of both cortisol and cortisone, and the cortisol-cortisone catalyzing enzyme 11β-hydroxysteroiddehydrogenase type 1 (11β-HSD1, in depressed patients and controls. Because the HPA axis is known to regulate the body’s immune system, relationships between measures of cytokines and cortisol were also assessed. Saliva samples were collected from 57 MDD patients and 40 healthy controls at five post-wakening time points (0, +30, +60, +720 and +750 min. Glucocorticoid concentrations were measured by liquid chromatography mass spectrometry. Whole blood mRNA expression of several inflammatory markers was measured by quantitative polymerase chain reaction. This study replicated the common finding of elevated morning cortisol and reduced CAR reactivity in MDD and found no differences in cortisone or 11β-HSD1 mRNA measures. There was a negative association between interleukin 1-β (IL-1β mRNA and morning cortisol reactivity within the depressed group, indicating that dysregulation of the HPA axis and immune system may be interconnected.

  6. Familial Longevity Is Not Associated with Major Differences in the Hypothalamic–Pituitary–Gonadal Axis in Healthy Middle-Aged Men

    DEFF Research Database (Denmark)

    van der Spoel, Evie; Roelfsema, Ferdinand; Jansen, Steffy W.

    2016-01-01

    longevity and controls. Design: We frequently sampled blood over 24 h in 10 healthy middle-aged male offspring of nonagenarian participants from the Leiden Longevity Study together with 10 male age-matched controls. Individual 24-h luteinizing hormone (LH) and testosterone concentration profiles were....../feedback regulation within the HPG axis were similar between offspring of long-lived families and controls. Conclusion: This relatively small study suggests that in healthy male middle-aged participants, familial longevity is not associated with major differences in the HPG axis. Selection on both fertility...

  7. Analysis of the effective point of measurement of a thimble chamber dosimeter set parallel to the X-ray beam axis

    International Nuclear Information System (INIS)

    Shimono, Tetsunori; Nanbu, Hidekazu; Koshida, Kichiro; Kikuchi, Yuzo

    2007-01-01

    To measure the narrow beam used in stereotactic irradiation, installation of the ionization chamber parallel to the X-ray beam axis has been used instead of perpendicular installation. However, the definition of the effective point is a major problem in the parallel installation. In this study, we analyzed the effective point in parallel installation, and considered the prediction and evaluation of measurement point displacement. Relative dosimetry was carried out by installing the thimble ionization chamber in both perpendicular and parallel configurations. We then searched for the measurement point that coincided with the percentage depth dose (PDD) of the perpendicular installation by using the displacement of the measurement point of the parallel installation. We found that the effective point of measurement for relative photon beam dosimetry depends on every detail of the chamber design, including the cavity length and the cavity radius. Moreover, the effective point of measurement also depends on the beam quality and the field size. The amount of effective point displacement for the parallel installation was quantified with the linear expression of tissue peak ratio (TPR) 20, 10 . Our results showed that the amount of effective point displacement can be estimated by the ionization volume of the dosimeter and the energy used. (author)

  8. Relationships of neuroticism and extraversion with axis I and II comorbidity among patients with DSM-IV major depressive disorder.

    Science.gov (United States)

    Jylhä, Pekka; Melartin, Tarja; Isometsä, Erkki

    2009-04-01

    High comorbidity with axis I and II disorders among major depressive disorder (MDD) patients may in part be due to the predisposing personality dimensions of neuroticism and extraversion. However, a comprehensive view of this relationship is lacking. MDD patients (n=193) in the Vantaa Depression Study were interviewed at baseline and at 6 and 18 months with the SCAN and SCID-II, and a general population comparison group (n=388) surveyed by mail. Neuroticism and extraversion were measured with the Eysenck Personality Inventory. A dose-exposure relationship between standardized levels of neuroticism and extraversion and type and number of comorbid axis I and II disorders among patients with MDD was hypothesized. Prevalence and number of comorbid axis I and II disorders increased significantly with increasing level of neuroticism. In contrast, as the level of extraversion increased, the prevalences of social phobia and cluster C personality disorders decreased. Patients with pure MDD or with any comorbid axis I or II disorder had z-scores of neuroticism of +0.46, +0.90 and +1.30 and of extraversion of -0.34, -0.47 and -0.84, respectively. Patients' personality scores were not pre-morbid. Among MDD patients, a positive dose-exposure relationship appears to exist between neuroticism and prevalence and number of comorbid axis I and II disorders. A negative relationship exists between level of extraversion and prevalence of social phobia and cluster C personality disorders. These findings are consistent with the hypothesis that high neuroticism and low extraversion predispose to comorbid axis I and II disorders among patients with MDD.

  9. The anteroposterior axis of the tibia in Korean patients undergoing total knee replacement.

    Science.gov (United States)

    Kim, C W; Seo, S S; Kim, J H; Roh, S M; Lee, C R

    2014-11-01

    The aim of this study was to find anatomical landmarks for rotational alignment of the tibial component in total knee replacement (TKR) in a CT-based study. Pre-operative CT scanning was performed on 94 South Korean patients (nine men, 85 women, 188 knees) with osteoarthritis of the knee joint prior to TKR. The tibial anteroposterior (AP) axis was defined as a line perpendicular to the femoral surgical transepicondylar axis and passing through the centre of the posterior cruciate ligament (PCL). The angles between the defined tibial AP axis and anatomical landmarks at various levels of the tibia were measured. The mean values of the angles between the defined tibial AP axis and the line connecting the anterior border of the proximal third of the tibia to the centre of the PCL was -0.2° (-17 to 14.1, sd 4.1). This was very close to the defined tibial axis, and remained so regardless of lower limb alignment and the degree of tibial bowing. Therefore, AP axis defined as described, is a reliable anatomical landmark for rotational alignment of tibial components. ©2014 The British Editorial Society of Bone & Joint Surgery.

  10. Synthesis of in-plane aligned a-axis YBa2Cu3O7-δ thin films

    International Nuclear Information System (INIS)

    Young, K.H.; Sun, J.Z.

    1991-01-01

    We report the successful synthesis of superconducting YBa 2 Cu 3 O 7-δ (YBCO) (100) thin films with alignment of the in-plane c axis. These films were grown on single crystal NdGaO 3 (110) substrates. The twofold symmetry of the substrate surface is believed to lead to anisotropic alignment of the in-plane c axis of the epitaxial YBCO (100) film. X-ray diffraction studies indicate that over 80% of the film grew epitaxially with the YBCO [100] perpendicular to the substrate surface, and YBCO [001] aligned along one pseudo-cubic axis of the NdGaO 3 . The superconductivity onset of the film was measured to be 89 K by ac susceptibility

  11. The transition from longitudinal to perpendicular recording

    International Nuclear Information System (INIS)

    Richter, H J

    2007-01-01

    After more than 30 years of research, hard disk drives using perpendicular recording are finally commercially available. This review is a follow-up of a review written in 1999 and addresses the basic physics of perpendicular recording with special emphasis on the read and the write process and the magnetic aspects of the recording media. The paper also surveys various technical difficulties which prevented an earlier implementation of perpendicular recording. The paper closes with a short overview of alternative technologies that allow even higher storage densities. (topical review)

  12. The association between the hypothalamic pituitary adrenal axis and tryptophan metabolism in persons with recurrent major depressive disorder and healthy controls

    NARCIS (Netherlands)

    Sorgdrager, F. J. H.; Doornbos, B.; Penninx, B. W. J. H.; de Jonge, P.; Kema, I. P.

    2017-01-01

    Objectives: Persistent changes in serotonergic and hypothalamic pituitary adrenal (HPA) axis functioning are implicated in recurrent types of major depressive disorder (MDD). Systemic tryptophan levels, which influence the rate of serotonin synthesis, are regulated by glucocorticoids produced along

  13. DARHT Axis-I Diode Simulations II: Geometrical Scaling

    Energy Technology Data Exchange (ETDEWEB)

    Ekdahl, Carl A. Jr. [Los Alamos National Laboratory

    2012-06-14

    Flash radiography of large hydrodynamic experiments driven by high explosives is a venerable diagnostic technique in use at many laboratories. Many of the largest hydrodynamic experiments study mockups of nuclear weapons, and are often called hydrotests for short. The dual-axis radiography for hydrodynamic testing (DARHT) facility uses two electron linear-induction accelerators (LIA) to produce the radiographic source spots for perpendicular views of a hydrotest. The first of these LIAs produces a single pulse, with a fixed {approx}60-ns pulsewidth. The second axis LIA produces as many as four pulses within 1.6-{micro}s, with variable pulsewidths and separation. There are a wide variety of hydrotest geometries, each with a unique radiographic requirement, so there is a need to adjust the radiographic dose for the best images. This can be accomplished on the second axis by simply adjusting the pulsewidths, but is more problematic on the first axis. Changing the beam energy or introducing radiation attenuation also changes the spectrum, which is undesirable. Moreover, using radiation attenuation introduces significant blur, increasing the effective spot size. The dose can also be adjusted by changing the beam kinetic energy. This is a very sensitive method, because the dose scales as the {approx}2.8 power of the energy, but it would require retuning the accelerator. This leaves manipulating the beam current as the best means for adjusting the dose, and one way to do this is to change the size of the cathode. This method has been proposed, and is being tested. This article describes simulations undertaken to develop scaling laws for use as design tools in changing the Axis-1 beam current by changing the cathode size.

  14. Spiraling contaminant electrons increase doses to surfaces outside the photon beam of an MRI-linac with a perpendicular magnetic field.

    Science.gov (United States)

    Hackett, Sara L; van Asselen, Bram; Wolthaus, Jochem W H; Bluemink, J J; Ishakoglu, Kübra; Kok, Jan G M; Lagendijk, Jan J W; Raaymakers, Bas W

    2018-03-29

    The transverse magnetic field of an MRI-linac sweeps contaminant electrons away from the radiation beam. Films oriented perpendicular to the magnetic field and 5cm from the radiation beam edge show a projection of the divergent beam, indicating that contaminant electrons spiral along magnetic field lines and deposit dose on surfaces outside the primary beam perpendicular to the magnetic field. These spiraling contaminant electrons (SCE) could increase skin doses to protruding regions of the patient along the cranio-caudal axis. This study investigated doses from SCE for an MRI-linac comprising a 7MV linac and a 1.5T MRI scanner. Surface doses to films perpendicular to the magnetic field and 5cm from the radiation beam edge showed increased dose within the projection of the primary beam, whereas films parallel to the magnetic field and 5cm from the beam edge showed no region of increased dose. However, the dose from contaminant electrons is absorbed within a few millimeters. For large fields, the SCE dose is within the same order of magnitude as doses from scattered and leakage photons. Doses for both SCE and scattered photons decrease rapidly with decreasing beam size and increasing distance from the beam edge. © 2018 Institute of Physics and Engineering in Medicine.

  15. Ferromagnetic resonance linewidth and damping in perpendicular-anisotropy magnetic multilayers thin films

    Science.gov (United States)

    Beaujour, Jean-Marc

    2010-03-01

    Transition metal ferromagnetic films with perpendicular magnetic anisotropy (PMA) have ferromagnetic resonance (FMR) linewidths that are one order of magnitude larger than soft magnetic materials, such as pure iron (Fe) and permalloy (NiFe) thin films. We have conducted systematic studies of a variety of thin film materials with perpendicular magnetic anisotropy to investigate the origin of the enhanced FMR linewidths, including Ni/Co and CoFeB/Co/Ni multilayers. In Ni/Co multilayers the PMA was systematically reduced by irradiation with Helium ions, leading to a transition from out-of-plane to in-plane easy axis with increasing He ion fluence [1,2]. The FMR linewidth depends linearly on frequency for perpendicular applied fields and increases significantly when the magnetization is rotated into the film plane with an applied in-plane magnetic field. Irradiation of the film with Helium ions decreases the PMA and the distribution of PMA parameters, leading to a large reduction in the FMR linewidth for in-plane magnetization. These results suggest that fluctuations in the PMA lead to a large two magnon scattering contribution to the linewidth for in-plane magnetization and establish that the Gilbert damping is enhanced in such materials (α˜0.04, compared to α˜0.002 for pure Fe) [2]. We compare these results to those on CoFeB/Co/Ni and published results on other thin film materials with PMA [e.g., Ref. 3]. [1] D. Stanescu et al., J. Appl. Phys. 103, 07B529 (2008). [2] J-M. L. Beaujour, D. Ravelosona, I. Tudosa, E. Fullerton, and A. D. Kent, Phys. Rev. B RC 80, 180415 (2009). [3] N. Mo, J. Hohlfeld, M. ulIslam, C. S. Brown, E. Girt, P. Krivosik, W. Tong, A. Rebel, and C. E. Patton, Appl. Phys. Lett. 92, 022506 (2008). *Research done in collaboration with: A. D. Kent, New York University, D. Ravelosona, Institut d'Electronique Fondamentale, UMR CNRS 8622, Universit'e Paris Sud, E. E. Fullerton, Center for Magnetic Recording Research, UCSD, and supported by NSF

  16. Light refraction in sapphire plates with a variable angle of crystal optical axis to the surface

    International Nuclear Information System (INIS)

    Vetrov, V. N.; Ignatenkov, B. A.

    2013-01-01

    The modification of sapphire by inhomogeneous plastic deformation makes it possible to obtain plates with a variable angle of inclination of the crystal optical axis to the plate surface. The refraction of light in this plate at perpendicular and oblique incidence of a parallel beam of rays is considered. The algorithm of calculating the refractive index of extraordinary ray and the birefringence is proposed.

  17. Tailoring perpendicular magnetic anisotropy with graphene oxide membranes

    KAUST Repository

    Ning, Keyu; Liu, Houfang; Li, Linsen; Li, Huanglong; Feng, Jiafeng; Yang, Baishun; Liu, Xiao; Li, Yuxing; Chen, Yanhui; Wei, Hongxiang; Han, Xiufeng; Mao, Shengcheng; Zhang, Xixiang; Yang, Yi; Ren, Tian-ling

    2017-01-01

    Graphene oxide (GO) membranes have been widely explored for their excellent physical and chemical properties, and abundant functional groups. In this work, we report the improvement of the perpendicular magnetic anisotropy (PMA) of CoFeB thin films by applying a coating of GO membranes. We observe that the PMA of the CoFeB/MgAl–O stacks is strongly enhanced by the coating of GO membranes and even reaches 0.6 mJ m−2 at room temperature after an annealing process. The critical thickness of the membrane-coated CoFeB for switching the magnetization from the out-of-plane to the in-plane axis exceeds 1.6 nm. First-principle calculations are performed to investigate the contribution of the GO membranes to the magnetic anisotropy energy (MAE). Due to changes in the hybridization of 3d orbitals, varying the location of the C atomic layer with Co changes the contribution of the Co–C stacks to PMA. Thus, the large PMA achieved with GO membranes can be attributed to the orbital hybridization of the C and O atoms with the Co orbitals. These results provide a comprehensive understanding of the PMA and point towards opportunities to achieve multifunctional graphene-composite spintronic devices.

  18. Tailoring perpendicular magnetic anisotropy with graphene oxide membranes

    KAUST Repository

    Ning, Keyu

    2017-11-15

    Graphene oxide (GO) membranes have been widely explored for their excellent physical and chemical properties, and abundant functional groups. In this work, we report the improvement of the perpendicular magnetic anisotropy (PMA) of CoFeB thin films by applying a coating of GO membranes. We observe that the PMA of the CoFeB/MgAl–O stacks is strongly enhanced by the coating of GO membranes and even reaches 0.6 mJ m−2 at room temperature after an annealing process. The critical thickness of the membrane-coated CoFeB for switching the magnetization from the out-of-plane to the in-plane axis exceeds 1.6 nm. First-principle calculations are performed to investigate the contribution of the GO membranes to the magnetic anisotropy energy (MAE). Due to changes in the hybridization of 3d orbitals, varying the location of the C atomic layer with Co changes the contribution of the Co–C stacks to PMA. Thus, the large PMA achieved with GO membranes can be attributed to the orbital hybridization of the C and O atoms with the Co orbitals. These results provide a comprehensive understanding of the PMA and point towards opportunities to achieve multifunctional graphene-composite spintronic devices.

  19. Perpendicular recording: the promise and the problems

    International Nuclear Information System (INIS)

    Wood, Roger; Sonobe, Yoshiaki; Jin Zhen; Wilson, Bruce

    2001-01-01

    Perpendicular recording has long been advocated as a means of achieving the highest areal densities. In particular, in the context of the 'superparamagnetic limit', perpendicular recording with a soft underlayer promises several key advantages. These advantages include a higher coercivity, thicker media that should permit smaller diameter grains and higher signal-to-noise ratio. Also, the sharper edge-writing will facilitate recording at very high track densities (lower bit aspect ratio). Recent demonstrations of the technology have shown densities comparable with the highest densities reported for longitudinal recording. This paper further examines the promise that perpendicular recording will deliver an increase in areal density two to eight times higher than that achievable with longitudinal recording. There are a number of outstanding issues but the key challenge is to create a low-noise medium with a coercivity that is high and is much larger than the remanent magnetization

  20. Discoveries that guided the beginning of perpendicular magnetic recording

    International Nuclear Information System (INIS)

    Iwasaki, S.

    2001-01-01

    The speculations and discoveries that guided the beginning of perpendicular magnetic recording, which have never been systematically discussed before, are described in this paper. Especially, four important discoveries of perpendicular magnetization, Co-Cr film, effect of double layered medium, and complementarity law are described in detail. The studies on thin film media and recording mechanisms at short wavelengths aiming at the advancement of longitudinal magnetic recording in the 1960's lead to the realization of the new perpendicular magnetic recording through these discoveries. None of these works was on any list of research targets in the 1960's. The study of perpendicular magnetic recording has taught us that research should proceed systematically with definite targets and that it is important to have an attitude not to neglect phenomena that are different from the common sense at the time

  1. HPA axis reactivity to pharmacologic and psychological stressors in euthymic women with histories of postpartum versus major depression.

    Science.gov (United States)

    Ferguson, Elizabeth H; Di Florio, Arianna; Pearson, Brenda; Putnam, Karen T; Girdler, Susan; Rubinow, David R; Meltzer-Brody, Samantha

    2017-06-01

    It is unclear whether women with a history of postpartum depression (PPD) have residual, abnormal hypothalamic-pituitary-adrenal (HPA) axis reactivity, as has been reported in major depression (MDD). Further unclear is whether the abnormalities in HPA axis reactivity associated with MDD represent a stable, underlying predisposition or a state-dependent phenomenon. This study sought the following: (1) to determine if euthymic postpartum women with a history of depression have an abnormal HPA axis reactivity to pharmacologic and psychological challenges and (2) to compare HPA reactivity in women with histories of PPD versus MDD. As a secondary objective, we wanted to determine the influence of trauma history on HPA axis function. Forty-five parous (12-24 months postpartum), euthymic women with history of MDD (n = 15), PPD (n = 15), and controls (n = 15) completed pharmacologic (dexamethasone/corticotropin-releasing hormone (CRH) test [DEX/CRH]) and psychological (Trier social stress test [TSST]) challenges during the luteal phase. Outcome measures were cortisol and adrenocorticotropic hormone (ACTH) response after DEX/CRH, and blood pressure, heart rate, epinephrine, norepinephrine, and cortisol response during the TSST. All groups had robust cortisol and ACTH response to DEX/CRH and cortisol response to TSST. Groups did not differ significantly in cortisol or ACTH response to DEX/CRH or in blood pressure, heart rate, epinephrine, norepinephrine, or cortisol response to TSST. Cortisol/ACTH ratio did not differ significantly between groups. Trauma history was associated with decreased cortisol response to DEX/CRH in women with histories of MDD, which was not significant after correction (F 8,125 , p = 0.02, Greenhouse-Geisser corrected p = 0.11). Currently euthymic women with histories of MDD or PPD did not demonstrate residual abnormal stress responsivity following administration of either a pharmacologic or psychological stressor.

  2. Read/write performance of perpendicular double-layered cylindrical media

    International Nuclear Information System (INIS)

    Yamada, H.; Shimatsu, T.; Watanabe, I.; Tsuchiyama, R.; Aoi, H.; Muraoka, H.; Nakamura, Y.

    2005-01-01

    A cylindrical magnetic storage system using perpendicular double-layered media has been developed. CoCrTa/CoZrNb deposited on a rotating cylindrical substrate shows perpendicular anisotropy and magnetic properties, which have almost the same characteristics as conventional disk-media. The fundamental read/write characteristics of perpendicular double-layered cylindrical media were measured using a single-pole-type (SPT) writer with a sliding-contact-type slider and a merged giant magneto-resistive (GMR) reader with a one-pad-type slider designed for use with cylindrical media. Preliminary studies for improving the characteristics of the recording layer are also described

  3. Variable property, steady, axi-symmetric, laminar, continuum plasma flow over spheroidal particles

    International Nuclear Information System (INIS)

    Wen Yuemin; Jog, Milind A.

    2005-01-01

    Steady, continuum, laminar plasma flow over spheroidal particles has been numerically investigated in this paper using a finite volume method. To body-fit the non-spherical particle surface, an adaptive orthogonal grid is generated. The flow field and the temperature distribution are calculated for oblate and prolate particle shapes. A number of particle surface temperatures and far field temperatures are considered and thermo-physical property variation is fully accounted for in our model. The particle shapes are represented in terms of axis ratio which is defined as the ratio of axis perpendicular to the flow direction to the axis along the flow direction. For oblate shape, axis ratios from 1.6 (disk-like) to 1 (sphere) are used whereas for prolate shape, axis ratios of 1(sphere) to 0.4 (cylinder-like) are used. Effects of flow Reynolds number, particle shape, surface and far field temperatures, and variable properties, on the flow field, temperature variations, drag coefficient, and Nusselt number are outlined. Results show that particle shape has significant effect on flow and heat transfer to particle surface. Compared to a constant property flow, accounting for thermo-physical property variation leads to prediction of higher temperature and velocity gradients in the vicinity of the particle surface. Based on the numerical results, a correlation for the Nusslet number is proposed that accounts for the effect of particle shape in continuum flow with large thermo-physical property variation

  4. Indium hexagonal island as seed-layer to boost a-axis orientation of AlN thin films

    Science.gov (United States)

    Redjdal, N.; Salah, H.; Azzaz, M.; Menari, H.; Manseri, A.; Guedouar, B.; Garcia-Sanchez, A.; Chérif, S. M.

    2018-06-01

    Highly a-axis oriented aluminum nitride films have been grown on Indium coated (100) Si substrate by DC reactive magnetron sputtering. It is shown that In incorporated layer improve the extent of preferential growth along (100) axis and form dense AlN films with uniform surface and large grains, devoid of micro-cracks. As revealed by SEM cross section images, AlN structure consists of oriented columnar grains perpendicular to the Si surface, while AlN/In structure results in uniformely tilted column. SEM images also revealed the presence of In hexagonal islands persistent throughout the entire growth. Micro -Raman spectroscopy of the surface and the cross section of the AlN/In grown films evidenced their high degree of homogeneity and cristallinity.

  5. Dynamics and morphology of chiral magnetic bubbles in perpendicularly magnetized ultra-thin films

    Science.gov (United States)

    Sarma, Bhaskarjyoti; Garcia-Sanchez, Felipe; Nasseri, S. Ali; Casiraghi, Arianna; Durin, Gianfranco

    2018-06-01

    We study bubble domain wall dynamics using micromagnetic simulations in perpendicularly magnetized ultra-thin films with disorder and Dzyaloshinskii-Moriya interaction. Disorder is incorporated into the material as grains with randomly distributed sizes and varying exchange constant at the edges. As expected, magnetic bubbles expand asymmetrically along the axis of the in-plane field under the simultaneous application of out-of-plane and in-plane fields. Remarkably, the shape of the bubble has a ripple-like part which causes a kink-like (steep decrease) feature in the velocity versus in-plane field curve. We show that these ripples originate due to the nucleation and interaction of vertical Bloch lines. Furthermore, we show that the Dzyaloshinskii-Moriya interaction field is not constant but rather depends on the in-plane field. We also extend the collective coordinate model for domain wall motion to a magnetic bubble and compare it with the results of micromagnetic simulations.

  6. Magnetization measurement of single La0.67Ca0.33MnO3 nanotubes in perpendicular magnetic fields using a micromechanical torsional oscillator

    International Nuclear Information System (INIS)

    Antonio, D.; Dolz, M.I.; Pastoriza, H.

    2010-01-01

    Using a silicon micromechanical resonator as a sensitive magnetometer, the authors have studied both experimentally and theoretically the magnetic behavior of two isolated ferromagnetic nanotubes of perovskite La 0.67 Ca 0.33 MnO 3 . The article investigates the specific configuration where a magnetic field H is applied perpendicular to the magnetic easy axis of an isolated nanotube characterized by an uniaxial anisotropy constant K. In this situation, the magnetization M reduces the effective elastic constant k M of the resonator. This softening of the mechanical system is opposed to the hardening effect of M observed in a previous work, where H was applied parallel to the easy axis. Moreover, in this magnetic field configuration two distinct magnetization regimes are manifested, depending on the magnitude of H. For H>>2K/M the magnetization is almost parallel to the applied magnetic field and for H<<2K/M it is almost parallel to the easy axis of the nanotube. At a certain value of H there is a sharp transition from one regime to the other, accompanied by a peak in the energy dissipation.

  7. Three-axis magnetic field induction sensor realized on buckled cantilever plate

    KAUST Repository

    Alfadhel, Ahmed; Carreno, Armando Arpys Arevalo; Foulds, Ian G.; Kosel, Jü rgen

    2013-01-01

    This work presents the fabrication and characterization of a three-axis induction sensor consisting of one planar microcoil, fixed on the substrate, and two microcoils fabricated on Bbuckled cantilever plates (BCP) oriented perpendicularly to the substrate and each other. The BCP allows an out-of-plane translation while preserving a direct connection to the substrate, which aids the routing of electrical lines. The fabricated sensor is integrated on a single substrate, allowing interaction and integration with other systems. The devices are fabricated using a MEMS polymer fabrication process. Different microcoil configurations are realized with 17-30 turns, 5 μm track width, and 15-20 μm track pitch. The sensor showed up to 6.8 nT/√Hz resolution to magnetic fields within a frequency range of 40 Hz to 1 MHz. The BCP concept provides a strikingly simple method to fabricate a three-axis field sensor that can readily be integrated with electronic circuits, and the sensor's performance can easily be adjusted within a wide range by changing the dimensions of the coils. © 2013 IEEE.

  8. Three-axis magnetic field induction sensor realized on buckled cantilever plate

    KAUST Repository

    Alfadhel, Ahmed

    2013-07-01

    This work presents the fabrication and characterization of a three-axis induction sensor consisting of one planar microcoil, fixed on the substrate, and two microcoils fabricated on Bbuckled cantilever plates (BCP) oriented perpendicularly to the substrate and each other. The BCP allows an out-of-plane translation while preserving a direct connection to the substrate, which aids the routing of electrical lines. The fabricated sensor is integrated on a single substrate, allowing interaction and integration with other systems. The devices are fabricated using a MEMS polymer fabrication process. Different microcoil configurations are realized with 17-30 turns, 5 μm track width, and 15-20 μm track pitch. The sensor showed up to 6.8 nT/√Hz resolution to magnetic fields within a frequency range of 40 Hz to 1 MHz. The BCP concept provides a strikingly simple method to fabricate a three-axis field sensor that can readily be integrated with electronic circuits, and the sensor\\'s performance can easily be adjusted within a wide range by changing the dimensions of the coils. © 2013 IEEE.

  9. Some design considerations for perpendicular biased ferrite tuners

    International Nuclear Information System (INIS)

    Enchevich, I.B.; Poirier, R.L.

    1994-10-01

    Recently remarkable progress has been achieved in the development of perpendicular biased ferrite tuned rf resonators for fast cycled synchrotrons. Compared with the broadly used parallel biased rf cavities they provide higher resonator quality factor Q. However when designing perpendicular biased cavities, special attention should be paid to the methods to provide eddy current suppression in the resonator walls, the ferrite nonlinearity influence, the generated heat removal, the fast self resonant frequency control. The prospective of a faster additional biasing system are discussed and conclusions are drawn. (author). 8 refs., 6 figs

  10. Modeling of Perpendicularly Driven Dual-Frequency Capacitively Coupled Plasma

    International Nuclear Information System (INIS)

    Wang Hongyu; Sun Peng; Zhao Shuangyun; Li Yang; Jiang Wei

    2016-01-01

    We analyzed perpendicularly configured dual-frequency (DF) capacitively coupled plasmas (CCP). In this configuration, two pairs of electrodes are arranged oppositely, and the discharging is perpendicularly driven by two radio frequency (RF) sources. Particle-in-cell/Monte Carlo (PIC/MC) simulation showed that the configuration had some advantages as this configuration eliminated some dual frequency coupling effects. Some variation and potential application of the discharging configuration is discussed briefly. (paper)

  11. Origin of perpendicular magnetic anisotropy in Co/Ni multilayers

    Science.gov (United States)

    Arora, M.; Hübner, R.; Suess, D.; Heinrich, B.; Girt, E.

    2017-07-01

    We studied the variation in perpendicular magnetic anisotropy of (111) textured Au /N ×[Co /Ni ]/Au films as a function of the number of bilayer repeats N . The ferromagnetic resonance and superconducting quantum interference device magnetometer measurements show that the perpendicular magnetic anisotropy of Co/Ni multilayers first increases with N for N ≤10 and then moderately decreases for N >10 . The model we propose reveals that the decrease of the anisotropy for N reduction in the magnetoelastic and magnetocrystalline anisotropies. A moderate decrease in the perpendicular magnetic anisotropy for N >10 is due to the reduction in the magnetocrystalline and the surface anisotropies. To calculate the contribution of magnetoelastic anisotropy in the Co/Ni multilayers, in-plane and out-of-plane x-ray diffraction measurements are performed to determine the spacing between Co/Ni (111) and (220) planes. The magnetocrystalline bulk anisotropy is estimated from the difference in the perpendicular and parallel g factors of Co/Ni multilayers that are measured using the in-plane and out-of-plane ferromagnetic resonance measurements. Transmission electron microscopy has been used to estimate the multilayer film roughness. These values are used to calculate the roughness-induced surface and magnetocrystalline anisotropy coefficients as a function of N .

  12. Bidirectional recording performance of a perpendicular evaporated Co-CoO tape

    Energy Technology Data Exchange (ETDEWEB)

    Motohashi, K. [Sony Corporation, 3-4-1 Sakuragi, Tagajo-shi, Miyagi 985-0842 (Japan)], E-mail: Kazunari.Motohashi@jp.sony.com; Ikeda, N.; Sato, T.; Shiga, D.; Ono, H.; Onodera, S. [Sony Corporation, 3-4-1 Sakuragi, Tagajo-shi, Miyagi 985-0842 (Japan)

    2008-11-15

    It is the first report on the recording performance of a perpendicular metal evaporated (ME) tape measured with a giant magnetoresistive head. To solve the application difficulty of oblique evaporated tape media to linear scan tape systems, a perpendicular evaporated Co-CoO tape was proposed instead. The prepared sample showed perpendicular anisotropy with coercivity of 107.3 kA/m, M{sub r}t of 3.9 mA and squareness of 0.25. Identical recording characteristics were obtained for both head-media moving directions, which enables the application of perpendicular evaporated Co-CoO tape to linear scan tape systems. The better carrier-to-noise ratio was also confirmed by comparison with a current advanced product of metal particulate tape, which can realize the higher recording density of linear scan tape systems using ME tape.

  13. Bidirectional recording performance of a perpendicular evaporated Co-CoO tape

    International Nuclear Information System (INIS)

    Motohashi, K.; Ikeda, N.; Sato, T.; Shiga, D.; Ono, H.; Onodera, S.

    2008-01-01

    It is the first report on the recording performance of a perpendicular metal evaporated (ME) tape measured with a giant magnetoresistive head. To solve the application difficulty of oblique evaporated tape media to linear scan tape systems, a perpendicular evaporated Co-CoO tape was proposed instead. The prepared sample showed perpendicular anisotropy with coercivity of 107.3 kA/m, M r t of 3.9 mA and squareness of 0.25. Identical recording characteristics were obtained for both head-media moving directions, which enables the application of perpendicular evaporated Co-CoO tape to linear scan tape systems. The better carrier-to-noise ratio was also confirmed by comparison with a current advanced product of metal particulate tape, which can realize the higher recording density of linear scan tape systems using ME tape

  14. NON-AXISYMMETRIC PERPENDICULAR DIFFUSION OF CHARGED PARTICLES AND THEIR TRANSPORT ACROSS TANGENTIAL MAGNETIC DISCONTINUITIES

    Energy Technology Data Exchange (ETDEWEB)

    Strauss, R. D.; Engelbrecht, N. E.; Dunzlaff, P. [Center for Space Research, North-West University, Potchefstroom, 2522 (South Africa); Roux, J. A. le [Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville, Huntsville, AL 3585 (United States); Ruffolo, D., E-mail: dutoit.strauss@nwu.ac.za [Department of Physics, Faculty of Science, Mahidol University, Bangkok 10400 (Thailand)

    2016-07-01

    We investigate the transport of charged particles across magnetic discontinuities, focusing specifically on stream interfaces associated with co-rotating interaction regions in the solar wind. We argue that the magnetic field fluctuations perpendicular to the magnetic discontinuity, and usually also perpendicular to the mean magnetic field, are strongly damped in the vicinity of such a magnetic structure, leading to anisotropic perpendicular diffusion. Assuming that perpendicular diffusion arises from drifts in a turbulent magnetic field, we adopt a simplified approach to derive the relevant perpendicular diffusion coefficient. This approach, which we believe gives the correct principal dependences as expected from more elaborate calculations, allows us to investigate transport in different turbulent geometries, such as longitudinal compressional turbulence that may be present near the heliopause. Although highly dependent on the (possibly anisotropic) perpendicular length scales and turbulence levels, we generally find perpendicular diffusion to be strongly damped at magnetic discontinuities, which may in turn provide an explanation for the large particle gradients associated with these structures.

  15. Tailoring of Perpendicular Magnetic Anisotropy in Dy13Fe87 Thin Films with Hexagonal Antidot Lattice Nanostructure

    Directory of Open Access Journals (Sweden)

    Mohamed Salaheldeen

    2018-04-01

    Full Text Available In this article, the magnetic properties of hexagonally ordered antidot arrays made of Dy13Fe87 alloy are studied and compared with corresponding ones of continuous thin films with the same compositions and thicknesses, varying between 20 nm and 50 nm. Both samples, the continuous thin films and antidot arrays, were prepared by high vacuum e-beam evaporation of the alloy on the top-surface of glass and hexagonally self-ordered nanoporous alumina templates, which serve as substrates, respectively. By using a highly sensitive magneto-optical Kerr effect (MOKE and vibrating sample magnetometer (VSM measurements an interesting phenomenon has been observed, consisting in the easy magnetization axis transfer from a purely in-plane (INP magnetic anisotropy to out-of-plane (OOP magnetization. For the 30 nm film thickness we have measured the volume hysteresis loops by VSM with the easy magnetization axis lying along the OOP direction. Using magnetic force microscopy measurements (MFM, there is strong evidence to suggest that the formation of magnetic domains with OOP magnetization occurs in this sample. This phenomenon can be of high interest for the development of novel magnetic and magneto-optic perpendicular recording patterned media based on template-assisted deposition techniques.

  16. Concept of a Programmable Fixture for 3-Axis CNC

    Directory of Open Access Journals (Sweden)

    Ahmad Dalloul

    2017-09-01

    Full Text Available CNC machine is the one of the major reasons for industrial advancement in recent decades for its ability of producing accurate parts. The most commen CNC machines are of 3-axis and adopted widely in the industrial sector. However, for producing more complicated parts 5-axis CNC machines are required. Although the introduction of the 5-axis machine came after the 3-axis CNC machine has established itself and many manufacturers did not make the move toward the newer model and its high pricing compared to the 3-axis model did not help either. In this time the development of a fixture or a platform to help transfer the 3-axis to a 5-axis to some degree. This paper discusses the concept of a programmable fixture that gives 3-axis CNC machine the freedom to act in similar manner as the 5-axis. The paper describes the mechanism with some initial results of the testing. Result showed that the platform moves in translation manner with an average error of 5.58 % and 7.303% average error for rotation movement.

  17. Amplification of perpendicular and parallel magnetic fields by cosmic ray currents

    Science.gov (United States)

    Matthews, J. H.; Bell, A. R.; Blundell, K. M.; Araudo, A. T.

    2017-08-01

    Cosmic ray (CR) currents through magnetized plasma drive strong instabilities producing amplification of the magnetic field. This amplification helps explain the CR energy spectrum as well as observations of supernova remnants and radio galaxy hotspots. Using magnetohydrodynamic simulations, we study the behaviour of the non-resonant hybrid (NRH) instability (also known as the Bell instability) in the case of CR currents perpendicular and parallel to the initial magnetic field. We demonstrate that extending simulations of the perpendicular case to 3D reveals a different character to the turbulence from that observed in 2D. Despite these differences, in 3D the perpendicular NRH instability still grows exponentially far into the non-linear regime with a similar growth rate to both the 2D perpendicular and 3D parallel situations. We introduce some simple analytical models to elucidate the physical behaviour, using them to demonstrate that the transition to the non-linear regime is governed by the growth of thermal pressure inside dense filaments at the edges of the expanding loops. We discuss our results in the context of supernova remnants and jets in radio galaxies. Our work shows that the NRH instability can amplify magnetic fields to many times their initial value in parallel and perpendicular shocks.

  18. A three axis turntable's online initial state measurement method based on the high-accuracy laser gyro SINS

    Science.gov (United States)

    Gao, Chunfeng; Wei, Guo; Wang, Qi; Xiong, Zhenyu; Wang, Qun; Long, Xingwu

    2016-10-01

    As an indispensable equipment in inertial technology tests, the three-axis turntable is widely used in the calibration of various types inertial navigation systems (INS). In order to ensure the calibration accuracy of INS, we need to accurately measure the initial state of the turntable. However, the traditional measuring method needs a lot of exterior equipment (such as level instrument, north seeker, autocollimator, etc.), and the test processing is complex, low efficiency. Therefore, it is relatively difficult for the inertial measurement equipment manufacturers to realize the self-inspection of the turntable. Owing to the high precision attitude information provided by the laser gyro strapdown inertial navigation system (SINS) after fine alignment, we can use it as the attitude reference of initial state measurement of three-axis turntable. For the principle that the fixed rotation vector increment is not affected by measuring point, we use the laser gyro INS and the encoder of the turntable to provide the attitudes of turntable mounting plat. Through this way, the high accuracy measurement of perpendicularity error and initial attitude of the three-axis turntable has been achieved.

  19. Dual-axis resonance testing of wind turbine blades

    Science.gov (United States)

    Hughes, Scott; Musial, Walter; White, Darris

    2014-01-07

    An apparatus (100) for fatigue testing test articles (104) including wind turbine blades. The apparatus (100) includes a test stand (110) that rigidly supports an end (106) of the test article (104). An actuator assembly (120) is attached to the test article (104) and is adapted for substantially concurrently imparting first and second forcing functions in first and second directions on the test article (104), with the first and second directions being perpendicular to a longitudinal axis. A controller (130) transmits first and second sets of displacement signals (160, 164) to the actuator assembly (120) at two resonant frequencies of the test system (104). The displacement signals (160, 164) initiate the actuator assembly (120) to impart the forcing loads to concurrently oscillate the test article (104) in the first and second directions. With turbine blades, the blades (104) are resonant tested concurrently for fatigue in the flapwise and edgewise directions.

  20. Some remarks about large p/sub perpendicular/ spin effects

    International Nuclear Information System (INIS)

    Field, R.D.

    1977-01-01

    A discussion of the ingredients necessary to make predictions concerning single and double spin measurements in large p/sub perpendicular to/ inclusive processes is presented. Remarks are made as to what might be expected and what might be learned from such measurements. Various models for the production of large p/sub perpendicular to/ mesons have quite different spin structure and hence can be expected to give differing predictions. However, it is not possible at this time to make quantitative calculations, and it is possible (not probable) that the interesting spin observables will be negligibly small

  1. Compression strength perpendicular to grain of structural timber and glulam

    DEFF Research Database (Denmark)

    Damkilde, Lars; Hoffmeyer, Preben; Pedersen, Torben N.

    1998-01-01

    The characteristic strength values for compression perpendicular to grain as they appear in EN 338 (structural timber) and EN 1194 (glulam) are currently up for discussion. The present paper provides experimental results based on EN 1193 that may assist in the correct assignment of such strength...... values. The dominant failure mode of glulam specimens is shown to be fundamentally different from that of structural timber specimens. Glulam specimens often show tension perpendicular to grain failure before the compression strength value is reached. Such failure mode is not seen for structural timber....... Nonetheless test results show that the levels of characteristic compression strength perpendicular to grain are of the same order for structural timber and glulam. The values are slightly lower than those appearing in EN 1194 and less than half of those appearing in EN 338. The paper presents a numerical...

  2. Magnetization measurement of single La{sub 0.67}Ca{sub 0.33}MnO{sub 3} nanotubes in perpendicular magnetic fields using a micromechanical torsional oscillator

    Energy Technology Data Exchange (ETDEWEB)

    Antonio, D., E-mail: dario.antonio@cab.cnea.gov.a [Comision Nacional de Energia Atomica, Centro Atomico Bariloche, (8400) S. C. de Bariloche (Argentina); Dolz, M.I.; Pastoriza, H. [Comision Nacional de Energia Atomica, Centro Atomico Bariloche, (8400) S. C. de Bariloche (Argentina)

    2010-03-15

    Using a silicon micromechanical resonator as a sensitive magnetometer, the authors have studied both experimentally and theoretically the magnetic behavior of two isolated ferromagnetic nanotubes of perovskite La{sub 0.67}Ca{sub 0.33}MnO{sub 3}. The article investigates the specific configuration where a magnetic field H is applied perpendicular to the magnetic easy axis of an isolated nanotube characterized by an uniaxial anisotropy constant K. In this situation, the magnetization M reduces the effective elastic constant k{sub M} of the resonator. This softening of the mechanical system is opposed to the hardening effect of M observed in a previous work, where H was applied parallel to the easy axis. Moreover, in this magnetic field configuration two distinct magnetization regimes are manifested, depending on the magnitude of H. For H>>2K/M the magnetization is almost parallel to the applied magnetic field and for H<<2K/M it is almost parallel to the easy axis of the nanotube. At a certain value of H there is a sharp transition from one regime to the other, accompanied by a peak in the energy dissipation.

  3. Exchange bias in nearly perpendicularly coupled ferromagnetic/ferromagnetic system

    International Nuclear Information System (INIS)

    Bu, K.M.; Kwon, H.Y.; Oh, S.W.; Won, C.

    2012-01-01

    Exchange bias phenomena appear not only in ferromagnetic/antiferromagnetic systems but also in ferromagnetic/ferromagnetic systems in which two layers are nearly perpendicularly coupled. We investigated the origin of the symmetry-breaking mechanism and the relationship between the exchange bias and the system's energy parameters. We compared the results of computational Monte Carlo simulations with those of theoretical model calculation. We found that the exchange bias exhibited nonlinear behaviors, including sign reversal and singularities. These complicated behaviors were caused by two distinct magnetization processes depending on the interlayer coupling strength. The exchange bias reached a maximum at the transition between the two magnetization processes. - Highlights: ► Exchange bias phenomena are found in perpendicularly coupled F/F systems. ► Exchange bias exhibits nonlinear behaviors, including sign reversal and singularities. ► These complicated behaviors were caused by two distinct magnetization processes. ► Exchange bias reached a maximum at the transition between the two magnetization processes. ► We established an equation to maximize the exchange bias in perpendicularly coupled F/F system.

  4. Fabrication and characterization of nano-particulate PtCo media for ultra-high density perpendicular magnetic recording

    International Nuclear Information System (INIS)

    Newman, Dave M; Wears, M Lesley; Jollie, Michael; Choo, Desmond

    2007-01-01

    The year-on-year growth in areal recording density maintained now for half a century by the hard disk industry has required a corresponding reduction in the size of the magnetic grains comprising the storage media employed. Grain dimensions are now such that the performance of materials which thus far have served the industry well can no longer be maintained as further reduction in their volume risks breaching the superparamagnetic limit with the attendant loss of data integrity. The high magnetocrystalline anisotropy of the Ll 0 phase of PtCo allows particles as small as 4 nm diameter to remain magnetically stable in the elevated temperature environment typical of disk drive systems. A non-interacting dispersion of nanomagnetic particles suspended in an inert non-magnetic host such that each has its anisotropy axis directed perpendicular to the surface of the medium now constitutes the new ideal for a recording medium. Fabrication by a novel combination of conventional sputtering and thermal processing technologies of a medium closely approximating this ideal is demonstrated. An optimized two-stage fabrication process produces a near mono-dispersion of particles with magnetic activation volumes centred about 5 x 10 23 and crystallized in the L1 0 phase with an orientated tetragonal structure. The characteristics of this medium are discussed as a function of composition and crystalline structure. In the absence of a thermally assisted recording head, experiments are conducted on a degraded form of the medium that is shown to support perpendicular recording at linear densities in excess of 240 kfci (D50 point)

  5. New Urban Vertical Axis Wind Turbine Design

    Directory of Open Access Journals (Sweden)

    Alexandru-Mihai CISMILIANU

    2015-12-01

    Full Text Available This paper develops a different approach for enhancing the performance of Vertical Axis Wind Turbines for the use in the urban or rural environment and remote isolated residential areas. Recently the vertical axis wind turbines (VAWT have become more attractive due to the major advantages of this type of turbines in comparison to the horizontal axis wind turbines. We aim to enhance the overall performance of the VAWT by adding a second set of blades (3 x 2=6 blades following the rules of biplane airplanes. The model has been made to operate at a maximum power in the range of the TSR between 2 to 2.5. The performances of the VAWT were investigated numerically and experimentally and justify the new proposed design.

  6. The role of magnetic loops in particle acceleration at nearly perpendicular shocks

    Science.gov (United States)

    Decker, R. B.

    1993-01-01

    The acceleration of superthermal ions is investigated when a planar shock that is on average nearly perpendicular propagates through a plasma in which the magnetic field is the superposition of a constant uniform component plus a random field of transverse hydromagnetic fluctuations. The importance of the broadband nature of the transverse magnetic fluctuations in mediating ion acceleration at nearly perpendicular shocks is pointed out. Specifically, the fluctuations are composed of short-wavelength components which scatter ions in pitch angle and long-wavelength components which are responsible for a spatial meandering of field lines about the mean field. At nearly perpendicular shocks the field line meandering produces a distribution of transient loops along the shock. As an application of this model, the acceleration of a superthermal monoenergetic population of seed protons at a perpendicular shock is investigated by integrating along the exact phase-space orbits.

  7. Nearly perpendicular wave propagation at the fundamental electron-cyclotron resonance

    International Nuclear Information System (INIS)

    Imre, K.; Weitzner, H.

    1985-01-01

    Waves propagating nearly perpendicular to the equilibrium magnetic field across the fundamental cyclotron resonance layer are studied by a boundary layer analysis for a weakly relativistic, inhomogeneous Vlasov plasma. The plasma is assumed to be perpendicularly stratified. It is found that the wave energy associated with the ordinary mode transmitted through the layer is independent of the relativistic corrections and is given by a geometrical optics formula. It is also found that there is no reflected energy associated with this mode when it is incident from the high-field side. These results are the same as the nonrelativistic case with purely perpendicular propagation. Relativistic effects produce a significant reduction of the reflection coefficient for low-field side incidence from the nonrelativistic value. Correspondingly, for this mode there is a considerable increase in the absorption rate for sufficiently high, but moderate, electron density and temperature

  8. Healthy and unhealthy dependence: implications for major depression.

    Science.gov (United States)

    Schulte, Fiona S; Mongrain, Myriam; Flora, David B

    2008-09-01

    To examine the contribution of varying levels of dependency to Axis I and Axis II disorders, and to the recurrence of major depression in a graduate student sample diagnosed with a history of the disorder. At Time 1, participants were interviewed to confirm a current or past episode of major depression along with the presence of Axis II and other current or past Axis I disorders. Various measures of dependency were administered including the Depressive Experiences Questionnaire (DEQ; Blatt, D'Afflitti, & Quinlan, 1976), the 3-Vector Dependency Inventory (3VDI; Pincus & Gurtman, 1995), and the Personal Style Inventory (PSI; Robins et al., 1994). Participants were interviewed 20 months later to determine the recurrence of a depressive episode. A factor analysis conducted on scale scores for each dependency measure resulted in three factors labelled 'unhealthy', 'intermediate', and 'healthy' dependence. Controlling for history of major depression, structural equation modelling found 'unhealthy' dependence to be the only predictor of recurrences of major depression and Axis II disorders, while 'healthy' dependence was related to fewer depressive symptoms. These results have important implications for the conceptualization of the dependency construct.

  9. Morphology of growth of Bi2Sr2CaCu2O8 single crystals

    Science.gov (United States)

    Indenbom, M. V.; van der Beek, C. J.; Berseth, V.; Wolf, Th.; Berger, H.; Benoit, W.

    1996-12-01

    A good correlation of twins on the basal surface of flux-grown Bi2Sr2CaCu2Ox (BSCCO) single crystals with surface. growth steps is observed, the b-axis being perpendicular to the steps and, thus, parallel to the growth direction. It is found that mono-twin BSCCO single crystals produced by the travelling solvent floating zone method also grow preferentially along b, i.e. nearly perpendicularly to the boule axis, contrary to the common belief. This new understanding of the morphology of growth explains the nature of major defects in these crystals, which considerably change their measured superconducting properties, in a different way.

  10. Origin of perpendicular magnetic anisotropy of SmCo5 thin films with Cu underlayer

    International Nuclear Information System (INIS)

    Sayama, Junichi; Mizutani, Kazuki; Asahi, Toru; Ariake, Jun; Ouchi, Kazuhiro; Osaka, Tetsuya

    2006-01-01

    Effects of the Cu underlayer thickness and the addition of Cu to a Sm-Co layer on magnetic properties and microstructure of SmCo 5 thin films exhibiting perpendicular magnetic anisotropy were studied. The origin of the perpendicular magnetic anisotropy was discussed from these experimental results. A thick Cu underlayer of more than 100 nm brought about high perpendicular magnetic anisotropy leading to the squareness ratio equal to unity. The Cu addition enhanced the perpendicular magnetic anisotropy and reduced the Cu underlayer thickness required to obtain the squareness ratio of unity. X-ray diffractometry showed that the crystalline orientation of the Sm-Co layer did not correlate with that of the Cu underlayer. Auger electron spectroscopy revealed that Cu atoms were diffused up to the Sm-Co layer from the Cu underlayer. From the results, Cu atoms existing in the Sm-Co layer were suggested to be strongly related with an appearance of the perpendicular magnetic anisotropy by introducing the Cu underlayer

  11. PLT and PDX perpendicular charge-exchange analyzers

    International Nuclear Information System (INIS)

    Mueller, D.; Hammett, G.W.; McCune, D.C.

    1986-01-01

    The perpendicular charge-exchange systems used on the poloidal divertor experiment and the Princeton large torus are comprised of ten-channel, mass-resolved, charge-exchange analyzers. Results from these systems indicate that instrumental effects can lead to erroneous temperature measurements during deuterium neutral beam injection or at low hydrogen concentrations

  12. Perpendicular Diffusion Coefficient of Comic Rays: The Presence of Weak Adiabatic Focusing

    Energy Technology Data Exchange (ETDEWEB)

    Wang, J. F.; Ma, Q. M.; Song, T.; Yuan, S. B. [Research Department of Biomedical Engineering, Institute of Electrical Engineering, Chinese Academy of Science, Beijing 100190 (China); Qin, G., E-mail: wangjunfang@mail.iee.ac.cn, E-mail: qingang@hit.edu.cn [School of Science, Harbin Institute of Technology, Shenzhen 518055 (China)

    2017-08-20

    The influence of adiabatic focusing on particle diffusion is an important topic in astrophysics and plasma physics. In the past, several authors have explored the influence of along-field adiabatic focusing on the parallel diffusion of charged energetic particles. In this paper, using the unified nonlinear transport theory developed by Shalchi and the method of He and Schlickeiser, we derive a new nonlinear perpendicular diffusion coefficient for a non-uniform background magnetic field. This formula demonstrates that the particle perpendicular diffusion coefficient is modified by along-field adiabatic focusing. For isotropic pitch-angle scattering and the weak adiabatic focusing limit, the derived perpendicular diffusion coefficient is independent of the sign of adiabatic focusing characteristic length. For the two-component model, we simplify the perpendicular diffusion coefficient up to the second order of the power series of the adiabatic focusing characteristic quantity. We find that the first-order modifying factor is equal to zero and that the sign of the second order is determined by the energy of the particles.

  13. Perpendicular Diffusion Coefficient of Comic Rays: The Presence of Weak Adiabatic Focusing

    Science.gov (United States)

    Wang, J. F.; Qin, G.; Ma, Q. M.; Song, T.; Yuan, S. B.

    2017-08-01

    The influence of adiabatic focusing on particle diffusion is an important topic in astrophysics and plasma physics. In the past, several authors have explored the influence of along-field adiabatic focusing on the parallel diffusion of charged energetic particles. In this paper, using the unified nonlinear transport theory developed by Shalchi and the method of He and Schlickeiser, we derive a new nonlinear perpendicular diffusion coefficient for a non-uniform background magnetic field. This formula demonstrates that the particle perpendicular diffusion coefficient is modified by along-field adiabatic focusing. For isotropic pitch-angle scattering and the weak adiabatic focusing limit, the derived perpendicular diffusion coefficient is independent of the sign of adiabatic focusing characteristic length. For the two-component model, we simplify the perpendicular diffusion coefficient up to the second order of the power series of the adiabatic focusing characteristic quantity. We find that the first-order modifying factor is equal to zero and that the sign of the second order is determined by the energy of the particles.

  14. Perpendicular Diffusion Coefficient of Comic Rays: The Presence of Weak Adiabatic Focusing

    International Nuclear Information System (INIS)

    Wang, J. F.; Ma, Q. M.; Song, T.; Yuan, S. B.; Qin, G.

    2017-01-01

    The influence of adiabatic focusing on particle diffusion is an important topic in astrophysics and plasma physics. In the past, several authors have explored the influence of along-field adiabatic focusing on the parallel diffusion of charged energetic particles. In this paper, using the unified nonlinear transport theory developed by Shalchi and the method of He and Schlickeiser, we derive a new nonlinear perpendicular diffusion coefficient for a non-uniform background magnetic field. This formula demonstrates that the particle perpendicular diffusion coefficient is modified by along-field adiabatic focusing. For isotropic pitch-angle scattering and the weak adiabatic focusing limit, the derived perpendicular diffusion coefficient is independent of the sign of adiabatic focusing characteristic length. For the two-component model, we simplify the perpendicular diffusion coefficient up to the second order of the power series of the adiabatic focusing characteristic quantity. We find that the first-order modifying factor is equal to zero and that the sign of the second order is determined by the energy of the particles.

  15. Development of an integrated model of personality, personality disorders and severe axis I disorders, with special reference to major affective disorders.

    Science.gov (United States)

    von Zerssen, Detlev

    2002-04-01

    A unidimensional model of the relationships between normal temperament, psychopathic variants of it and the two main forms of so-called endogenous psychoses (major affective disorders and schizophrenia) was derived from Kretschmer's constitutional typology. It was, however, not confirmed by means of a biometric approach nor was Kretschmer's broad concept of cyclothymia as a correlate of physical stoutness on the one hand and major affective disorders on the other supported by empirical data. Yet the concept of the 'melancholic type' of personality of patients with severe unipolar major depression (melancholia) which resembles descriptions by psychoanalysts could be corroborated. This was also true for the 'manic type' of personality as a (premorbid) correlate of predominantly manic forms of a bipolar I disorder. As predicted from a spectrum concept of major affective disorders, the ratio of traits of either type co-varied with the ratio of the depressive and the manic components in the long-term course of such a disorder. The two types of premorbid personality and a rare variant of the 'manic type', named 'relaxed, easy-going type', were conceived as 'affective types' dominating in major affective disorders. They are opposed to three 'neurotoid types' prevailing in so-called neurotic disorders as well as in schizophrenic psychoses. The similarity among the types can be visualized as spatial relationships in a circular, i.e. a two-dimensional, model (circumplex). Personality disorders as maladapted extreme variants of personality are, by definition, located outside the circle, mainly along its 'neurotoid' side. However, due to their transitional nature, axis I disorders cannot be represented adequately within the plane which represents (adapted as well as maladapted) forms of habitual behaviour (personality types and disorders, respectively). To integrate them into the spatial model of similarity interrelations, a dimension of actual psychopathology has to be added

  16. Gyrokinetic theory of perpendicular cyclotron resonance in a nonuniformly magnetized plasma

    International Nuclear Information System (INIS)

    Lashmore-Davies, C.N.; Dendy, R.O.

    1989-01-01

    The extension of gyrokinetic theory to arbitrary frequencies by Chen and Tsai [Phys. Fluids 26, 141 (1983); Plasma Phys. 25, 349 (1983)] is used to study cyclotron absorption in a straight magnetic field with a perpendicular, linear gradient in strength. The analysis includes the effects of magnetic field variation across the Larmor orbit and is restricted to propagation perpendicular to the field. It yields the following results for propagation into the field gradient. The standard optical depths for the fundamental O-mode and second harmonic X-mode resonances are obtained from the absorption profiles given in this paper, without invoking relativistic mass variation [see also Antonsen and Manheimer, Phys. Fluids 21, 2295 (1978)]. The compressional Alfven wave is shown to undergo perpendicular cyclotron damping at the fundamental minority resonance in a two-ion species plasma and at second harmonic resonance in a single-ion species plasma. Ion Bernstein waves propagating into the second harmonic resonance are no longer unattenuated, but are increasingly damped as they approach the resonance. It is shown how the kinetic power flow affects absorption profiles, yielding information previously obtainable only from full-wave theory. In all cases, the perpendicular cyclotron damping arises from the inclusion of magnetic field variation across the Larmor orbit

  17. Absorption of nearly perpendicularly propagating waves in the second harmonic layer

    International Nuclear Information System (INIS)

    Imre, K.; Weitzner, H.

    1985-01-01

    Propagation of waves nearly perpendicular to the equilibrium magnetic field and incident to the second electron-cyclotron harmonic layer is investigated in an inhomogeneous weakly relativistic plasma. The resonance region is treated by a boundary layer analysis, and the solutions are matched to the geometrical optics solutions outside the layer. This approach allows one to investigate the transmission, mode coupling, reflection, absorption, and the effects of relativistic broadening. This work extends a previous investigation with the purely perpendicular propagation. It is shown that the mode conversion and reflection rapidly cease to be of importance outside a narrow propagation cone as the doppler broadening becomes predominant. The geometrical optics approach, which breaks down in the purely perpendicular propagation, then becomes valid. It is also shown that the transmission coefficient and the reflection from the high-field side incidence are not altered within this cone

  18. Food and the circadian activity of the hypothalamic-pituitary-adrenal axis

    Directory of Open Access Journals (Sweden)

    A.M.O. Leal

    1997-12-01

    Full Text Available Temporal organization is an important feature of biological systems and its main function is to facilitate adaptation of the organism to the environment. The daily variation of biological variables arises from an internal time-keeping system. The major action of the environment is to synchronize the internal clock to a period of exactly 24 h. The light-dark cycle, food ingestion, barometric pressure, acoustic stimuli, scents and social cues have been mentioned as synchronizers or" zeitgebers". The circadian rhythmicity of plasma corticosteroids has been well characterized in man and in rats and evidence has been accumulated showing daily rhythmicity at every level of the hypothalamic-pituitary-adrenal (HPA axis. Studies of restricted feeding in rats are of considerable importance because they reveal feeding as a major synchronizer of rhythms in HPA axis activity. The daily variation of the HPA axis stress response appears to be closely related to food intake as well as to basal activity. In humans, the association of feeding and HPA axis activity has been studied under physiological and pathological conditions such as anorexia nervosa, bulimia, malnutrition, obesity, diabetes mellitus and Cushing's syndrome. Complex neuroanatomical pathways and neurochemical circuitry are involved in feeding-associated HPA axis modulation. In the present review we focus on the interaction among HPA axis rhythmicity, food ingestion, and different nutritional and endocrine states

  19. The mystery of perpendicular fivefold axes and the fourth dimension in intermetallic structures.

    Science.gov (United States)

    Berger, Robert F; Lee, Stephen; Johnson, Jeffreys; Nebgen, Ben; Sha, Fernando; Xu, Jiaqi

    2008-01-01

    The structures of eight related known intermetallic structure types are the impetus to this paper: Li21Si5, Mg44Rh7, Zn13(Fe,Ni)2, Mg6Pd, Na6Tl, Zn91Ir11, Li13Na29Ba19, and Al69Ta39. All belong to the F43m space group, have roughly 400 atoms in their cubic unit cells, are built up at least partially from the gamma-brass structure, and exhibit pseudo-tenfold symmetric diffraction patterns. These pseudo-tenfold axes lie in the {110} directions, and thus present a paradox. The {110} set is comprised of three pairs of perpendicular directions. Yet no 3D point group contains a single pair of perpendicular fivefold axes (by Friedel's Law, a fivefold axis leads to a tenfold diffraction pattern). The current work seeks to resolve this paradox. Its resolution is based on the largest of all 4D Platonic solids, the 600-cell. We first review the 600-cell, building an intuition discussing 4D polyhedroids (4D polytopes). We then show that the positions of common atoms in the F43m structures lie close to the positions of vertices in a 3D projection of the 600-cell. For this purpose, we develop a projection method that we call intermediate projection. The introduction of the 600-cell resolves the above paradox. This 4D Platonic solid contains numerous orthogonal fivefold rotations. The six fivefold directions that are best preserved after projection prove to lie along the {110} directions of the F43m structures. Finally, this paper shows that at certain ideal projected cluster sizes related to one another by the golden mean (tau=(1+ radical 5)/2), constructive interference leading to tenfold diffraction patterns is optimized. It is these optimal values that predominate in actual F43m structures. Explicit comparison of experimental cluster sizes and theoretically derived cluster sizes shows a clear correspondence, both for isolated and crystalline pairs of projected 600-cells.

  20. Perpendicular magnetic anisotropy in CoXPd100-X alloys for magnetic tunnel junctions

    Science.gov (United States)

    Clark, B. D.; Natarajarathinam, A.; Tadisina, Z. R.; Chen, P. J.; Shull, R. D.; Gupta, S.

    2017-08-01

    CoFeB/MgO-based perpendicular magnetic tunnel junctions (p-MTJ's) with high anisotropy and low damping are critical for spin-torque transfer random access memory (STT-RAM). Most schemes of making the pinned CoFeB fully perpendicular require ferrimagnets with high damping constants, a high temperature-grown L10 alloy, or an overly complex multilayered synthetic antiferromagnet (SyAF). We report a compositional study of perpendicular CoxPd alloy-pinned Co20Fe60B20/MgO based MTJ stacks, grown at moderate temperatures in a planetary deposition system. The perpendicular anisotropy of the CoxPd alloy films can be tuned based on the layer thickness and composition. The films were characterized by alternating gradient magnetometry (AGM), energy-dispersive X-rays (EDX), and X-ray diffraction (XRD). Current-in-plane tunneling (CIPT) measurements have also been performed on the compositionally varied CoxPd MTJ stacks. The CoxPd alloy becomes fully perpendicular at approximately x = 30% (atomic fraction) Co. Full-film MTJ stacks of Si/SiO2/MgO (13)/CoXPd100-x (50)/Ta (0.3)/CoFeB (1)/MgO (1.6)/CoFeB (1)/Ta (5)/Ru (10), with the numbers enclosed in parentheses being the layer thicknesses in nm, were sputtered onto thermally oxidized silicon substrates and in-situ lamp annealed at 400 °C for 5 min. CIPT measurements indicate that the highest TMR is observed for the CoPd composition with the highest perpendicular magnetic anisotropy.

  1. Symmetry mismatch-driven perpendicular magnetic anisotropy for perovskite/brownmillerite heterostructures.

    Science.gov (United States)

    Zhang, Jing; Zhong, Zhicheng; Guan, Xiangxiang; Shen, Xi; Zhang, Jine; Han, Furong; Zhang, Hui; Zhang, Hongrui; Yan, Xi; Zhang, Qinghua; Gu, Lin; Hu, Fengxia; Yu, Richeng; Shen, Baogen; Sun, Jirong

    2018-05-15

    Grouping different transition metal oxides together by interface engineering is an important route toward emergent phenomenon. While most of the previous works focused on the interface effects in perovskite/perovskite heterostructures, here we reported on a symmetry mismatch-driven spin reorientation toward perpendicular magnetic anisotropy in perovskite/brownmillerite heterostructures, which is scarcely seen in tensile perovskite/perovskite heterostructures. We show that alternately stacking perovskite La 2/3 Sr 1/3 MnO 3 and brownmillerite LaCoO 2.5 causes a strong interface reconstruction due to symmetry discontinuity at interface: neighboring MnO 6 octahedra and CoO 4 tetrahedra at the perovskite/brownmillerite interface cooperatively relax in a manner that is unavailable for perovskite/perovskite interface, leading to distinct orbital reconstructions and thus the perpendicular magnetic anisotropy. Moreover, the perpendicular magnetic anisotropy is robust, with an anisotropy constant two orders of magnitude greater than the in-plane anisotropy of the perovskite/perovskite interface. The present work demonstrates the great potential of symmetry engineering in designing artificial materials on demand.

  2. Perpendicular relativistic shocks in magnetized pair plasma

    Science.gov (United States)

    Plotnikov, Illya; Grassi, Anna; Grech, Mickael

    2018-04-01

    Perpendicular relativistic (γ0 = 10) shocks in magnetized pair plasmas are investigated using two dimensional Particle-in-Cell simulations. A systematic survey, from unmagnetized to strongly magnetized shocks, is presented accurately capturing the transition from Weibel-mediated to magnetic-reflection-shaped shocks. This transition is found to occur for upstream flow magnetizations 10-3 10-2, it leaves place to a purely electromagnetic precursor following from the strong emission of electromagnetic waves at the shock front. Particle acceleration is found to be efficient in weakly magnetized perpendicular shocks in agreement with previous works, and is fully suppressed for σ > 10-2. Diffusive Shock Acceleration is observed only in weakly magnetized shocks, while a dominant contribution of Shock Drift Acceleration is evidenced at intermediate magnetizations. The spatial diffusion coefficients are extracted from the simulations allowing for a deeper insight into the self-consistent particle kinematics and scale with the square of the particle energy in weakly magnetized shocks. These results have implications for particle acceleration in the internal shocks of AGN jets and in the termination shocks of Pulsar Wind Nebulae.

  3. Perpendicularity misjudgments caused by contextual stimulus elements.

    Science.gov (United States)

    Bulatov, Aleksandr; Bulatova, Natalija; Surkys, Tadas

    2012-10-15

    It has been demonstrated in previous studies that the illusions of extent of the Brentano type can be explained by the perceptual positional shifts of the stimulus terminators in direction of the centers-of-masses (centroids) of adjacent contextual flanks [Bulatov, A. et al. (2011). Contextual flanks' tilting and magnitude of illusion of extent. Vision Research, 51(1), 58-64]. In the present study, the applicability of the centroid approach to explain the right-angle misjudgments was tested psychophysically using stimuli composed of three small disks (dots) forming an imaginary rectangular triangle. Stimuli comprised the Müller-Lyer wings or line segments (bars) as the contextual distracters rotated around the vertices of the triangle, and changes in the magnitude of the illusion of perpendicularity were measured in a set of experiments. A good resemblance between the experimental data and theoretical predictions obtained strongly supports the suggestion regarding the common "centroid" origin of the illusions of extent of the Brentano type and misperception of the perpendicularity investigated. 2012 Elsevier Ltd. All rights reserved

  4. Photo-orientation of azobenzene side chain polymers parallel or perpendicular to the polarization of red HeNe light

    International Nuclear Information System (INIS)

    Kempe, Christian; Rutloh, Michael; Stumpe, Joachim

    2003-01-01

    The mechanism of the light-induced orientation process of azobenzene-containing polymers caused by irradiation with linearly polarized red light is investigated. This process is surprising because there is almost no absorption at 633 nm. Depending on the photochemical pre-treatment and the exposure time, the azobenzene moieties can undergo two different orientation processes resulting in either a parallel or a perpendicular orientation with respect to the electric field vector of the incident light. The fast orientation of the photochromic groups with their long axis in the direction of the light polarization requires a photochemical pre-treatment in which non-polarized UV light generates Z-isomers. Due to this procedure the film becomes 'photochemically activated' for the subsequent polarized irradiation with red light. But on continued exposure a second, much slower reorientation process occurs which establishes an orientation of the azobenzene groups perpendicular to the electric field vector. The fast mechanism is probably caused by an angle-selective photo-isomerization of the Z-isomers to the E-isomers, while the subsequent slow reorientation process is caused by the well-known conventional photo-orientation taking place via the accumulation of a number of photoselection steps and the rotational diffusion minimizing the absorbance of the E-isomer. This process occurs in the steady state but at this wavelength with a very small concentration of Z-isomers. The competing mechanisms take place in the same polymer film under almost identical irradiation conditions, differing only in the actual concentration of the Z-isomers

  5. Magnetic and transport properties of single and double perpendicular magnetic tunnel junctions

    International Nuclear Information System (INIS)

    Cuchet, Lea

    2015-01-01

    Due to their advantageous properties in terms of data retention, storage density and critical current density for Spin Transfer Torque (STT) switching, the magnetic tunnel junctions with perpendicular anisotropy have become predominant in the developments for MRAM applications. The aim of this thesis is to improve the anisotropy and transport properties of such structures and to realize even more complex stacks such as perpendicular double junctions. Studies on the magnetic properties and Tunnel Magnetoresistance (TMR) measurements showed that to optimize the performances of the junctions, all the thicknesses of the different layers constituting the stack have to be adapted. To guaranty both a large TMR as well a strong perpendicular anisotropy, compromises are most of the time needed. Studies as a function of magnetic thickness enabled to extract the saturation magnetization, the critical thickness and the magnetic dead layer thickness both in the bottom reference and the top storage layer in structures capped with Ta. This type of junction could be tested electrically after patterning the sample into nano-pillars. Knowing that perpendicular anisotropy mostly arises at the metal/oxide interface, the Ta capping layer was replaced by a MgO one, leading to a huge increase in the anisotropy of the free layer. A second top reference was then added on such a stack to create functional perpendicular double junctions. CoFeB/insertion/CoFeB synthetic antiferromagnetic storage layers could be developed and were proved to be stable enough to replace the standard Co/Pt-based reference layers. (author) [fr

  6. 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.

  7. Studies in perpendicular magnetic recording

    Science.gov (United States)

    Valcu, Bogdan F.

    This dissertation uses both micromagnetic simulation and analytical methods to analyze several aspects of a perpendicular recording system. To increase the head field amplitude, the recording layer is grown on top of a soft magnetic layer (keeper). There is concern about the ability of the keeper to conduct the magnetic flux from the head at high data rates. We compute numerically the magnetization motion of the soft underlayer during the reversal process. Generation of non-linear spin waves characterizes the magnetization dynamics in the keeper, the spins are oscillating with a frequency higher than that of the reversal current. However, the recording field applied to the data layer follows the time dependence of the input wave form. The written transition shape is determined by the competition between the head field gradient and the demagnetizing field gradient. An analytical slope model that takes into consideration the angular orientation of the applied field is used to estimate the transition parameter; agreement is shown with the micromagnetic results. On the playback side, the reciprocity principle is applied to calculate the read out signal from a single magnetic transition in the perpendicular medium. The pulse shape is close to an error-function, going through zero when the sensor is above the transition center and decaying from the peak to an asymptotic value when the transition center is far away. Analytical closed forms for both the slope in the origin and the asymptotic value show the dependence on the recording geometry parameters. The Signal-to-Noise Ratio is calculated assuming that the noise is dominated by the medium jitter. To keep the SNR at a readable level while increasing the areal density, the average magnetic grain diameter must decrease; consequently grain size fluctuations will affect the thermal decay. We performed Transmission Electron Microscopy measurements and observed differences in the grain size distribution between various types

  8. A novel vertical-axis wind turbine for distributed and utility deployment

    Energy Technology Data Exchange (ETDEWEB)

    Park, J.Y. [Inha Univ., Incheon (Korea, Republic of); Lee, S. [Inha Univ., Incheon (Korea, Republic of)]|[KR Wind Energy Research Inst., Incheon (Korea, Republic of); Sabourin, T.; Park, K. [KR Windpower Inc., (United States)

    2008-07-01

    The rapid growth in the wind power industry can be attributed to energy cost saving, power reliability, grid support, and environmental concerns. Wind turbines should also comply with community noise and aesthetic requirements as well as meet a strong need for high capacity. Wind Turbine Generator Systems are classified as either horizontal axis wind turbine (HAWT) or vertical axis wind turbine (VAWT) depending on whether their axis of rotation is parallel or perpendicular to the ground. The average electric power produced by the wind turbine is proportional to the efficiency of the rotor, air density, projected area of the turbine, and cube of wind speed. The capacity factor should be increased to guarantee the economics of the turbine via increase in the rotor size or the turbine efficiency. The low rotational speed of VAWT rotors suggests that the machine will be quieter than the high-rotational speed of HAWTs, thereby being potentially suitable for applications closer to population centres. The slow rotating machine may also be considered to be visually more aesthetic. This paper presented the measured performance of a small-scale VAWT rated as 1 kW which has a tail consisting of a stabilizer and a rudder. It was tested for its electric power produced at specified wind conditions in an open-type wind tunnel. In order to eliminate the inevitable blockage effect by the size of turbine, the flow deceleration effect of the incoming air to the turbine was analyzed through model testing and numerical simulation and implemented to the proto-type testing. The turbine and its furling tail was shown to be safe. 9 refs., 1 tab., 10 figs.

  9. Interfacial tuning of perpendicular magnetic anisotropy and spin magnetic moment in CoFe/Pd multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Ngo, D.-T., E-mail: ndthe82@gmail.com [Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576 (Singapore); Meng, Z.L. [Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576 (Singapore); Tahmasebi, T. [Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576 (Singapore); Data Storage Institute, A-STAR (Agency for Science Technology and Research), 5 Engineering Drive 1, Singapore 117608 (Singapore); Yu, X. [Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore 117603 (Singapore); Thoeng, E. [Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore 117603 (Singapore); Department of Physics, National University of Singapore, Singapore 117542 (Singapore); Yeo, L.H. [Department of Physics, National University of Singapore, Singapore 117542 (Singapore); Rusydi, A., E-mail: phyandri@nus.edu.sg [Singapore Synchrotron Light Source, National University of Singapore, 5 Research Link, Singapore 117603 (Singapore); Department of Physics, National University of Singapore, Singapore 117542 (Singapore); Han, G.C [Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576 (Singapore); Teo, K.-L., E-mail: eleteokl@nus.edu.sg [Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore 117576 (Singapore)

    2014-01-15

    We report on a strong perpendicular magnetic anisotropy in [CoFe 0.4 nm/Pd t]{sub 6} (t=1.0–2.0 nm) multilayers fabricated by DC sputtering in an ultrahigh vacuum chamber. Saturation magnetization, M{sub s}, and uniaxial anisotropy, K{sub u}, of the multilayers decrease with increasing the spacing thickness; with a M{sub s} of 155 emu/cc and a K{sub u} of 1.14×10{sup 5} J/m{sup 3} at a spacing thickness of t=2 nm. X-ray absorption spectroscopy and X-ray magnetic circular dichroism measurements reveal that spin and orbital magnetic moments of Co and Fe in CoFe film decrease as a function of Pd thickness, indicating the major contribution of surface/interfacial magnetism to the magnetic properties of the film. - Highlights: • Strong perpendicular magnetic anisotropy essentially contributed by interfacial anisotropy. • Controllably magnetic properties with low M{sub s}, high K{sub u}, high P. • Interfacial magnetic moments modified by CoFe/Pd interfaces with strong spin–orbit coupling. • Narrow Bloch walls with Néel caps. • Superior magnetic characteristics for spin-torque applications.

  10. A New Circuit Model for Spin-Torque Oscillator Including Perpendicular Torque of Magnetic Tunnel Junction

    Directory of Open Access Journals (Sweden)

    Hyein Lim

    2013-01-01

    Full Text Available Spin-torque oscillator (STO is a promising new technology for the future RF oscillators, which is based on the spin-transfer torque (STT effect in magnetic multilayered nanostructure. It is expected to provide a larger tunability, smaller size, lower power consumption, and higher level of integration than the semiconductor-based oscillators. In our previous work, a circuit-level model of the giant magnetoresistance (GMR STO was proposed. In this paper, we present a physics-based circuit-level model of the magnetic tunnel junction (MTJ-based STO. MTJ-STO model includes the effect of perpendicular torque that has been ignored in the GMR-STO model. The variations of three major characteristics, generation frequency, mean oscillation power, and generation linewidth of an MTJ-STO with respect to the amount of perpendicular torque, are investigated, and the results are applied to our model. The operation of the model was verified by HSPICE simulation, and the results show an excellent agreement with the experimental data. The results also prove that a full circuit-level simulation with MJT-STO devices can be made with our proposed model.

  11. Spherulitic (c-axis) Growth for Terrestrial (Mauna Kea, Hawaii) and Martian Hematite "blueberries"

    Science.gov (United States)

    Golden, D. C.; Ming, D. W.; Morris, R. V.

    2006-01-01

    Hematite concentrations observed by Thermal Emission Spectrometer (TES) onboard Mars Global Surveyor were considered a possible indicator for aqueous processes on Mars. Observations made by Opportunity show that the hematite at Meridiani Planum is present as spherules ( blueberries) and their fragments. The internal structure of the hematite spherules is not discernable at the resolution limit (approx.30 m/pixel) of Opportunity s Microscopic Imager (MI). A terrestrial analog for martian hematite spherules are spherules from hydrothermally altered and sulfate-rich tephra from the summit region of Mauna Kea volcano, Hawaii. The objective of this study is to determine the crystal growth fabric of the Mauna Kea hematite spherules using transmission electron microscopy (TEM) techniques and to relate that crystalline fabric to the observed TES signature of Meridiani Planum "blueberries." TEM analysis of Mauna Kea spherules exhibited a radial growth pattern consisting of "fibrous" hematite with the c-axis of hematite particles aligned along the elongation direction of the hematite fibers. The individual fibers appear to be made of coalesced nano-particles of hematite arranged with their c-axis oriented radially to form a spherical structure. Lattice fringes suggest long-range order across particles and along fibers. According to interpretations of thermal emission spectra for Meridian Planum hematite, the absence of a band at approx. 390/cm implies a geometry where c-face emission dominates. Because the c-face is perpendicular to the c-axis, this is precisely the geometry for the Mauna Kea spherules because the c-axis is aligned parallel to their radial growth direction. Therefore, we conclude as a working hypothesis that the martian spherules also have radial, c-axis growth pattern on a scale that is too small to be detected by the MER MI. Furthermore, by analogy with the Mauna Kea spherules, the martian blueberries could have formed during hydrothermal alteration of

  12. Room temperature deposition of perpendicular magnetic anisotropic Co{sub 3}Pt thin films on glass substrate

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yu-Shen; Dai, Hong-Yu; Hsu, Yi-Wei [Department of Chemical Engineering and Materials Science, Yuan-Ze University, Chung-Li 32003, Taiwan (China); Ou, Sin-Liang, E-mail: slo@mail.dyu.edu.tw [Department of Materials Science and Engineering, Da-Yeh University, Changhua 51591, Taiwan (China); Chen, Shi-Wei [National Synchrotron Radiation Research Center (NSRRC), Hsinchu 300, Taiwan (China); Lu, Hsi-Chuan; Wang, Sea-Fue [Department of Materials and Mineral Resources Engineering, National Taipei University of Technology, Taipei 106, Taiwan (China); Sun, An-Cheng, E-mail: acsun@saturn.yzu.edu.tw [Department of Chemical Engineering and Materials Science, Yuan-Ze University, Chung-Li 32003, Taiwan (China)

    2017-03-01

    Co{sub 3}Pt alloy thin films were deposited on the glass substrate at room temperature (RT) and 300 °C, which showed high perpendicular magnetic anisotropy (PMA) and isotropy magnetic behaviors, respectively. Co{sub 3}Pt HCP (0002) planes grew along the substrate plane for the films deposited at RT. The easy axis [0001] was consequently vertical to the substrate surface and obtained the predominant PMA. Large magnetic domains and sharp boundary also supported high PMA in RT-deposited samples. On the other hand, the PMA was significantly decreased with increasing the deposition temperature from RT to 300 °C. Hard HCP(0002) and soft A1(111) co-existed in the film and the magnetic exchanged coupling between these two phases induced isotropy magnetic behavior. In addition, the various thicknesses (t) of the RT-deposited Co{sub 3}Pt films were deposited with different base pressures prior to sputtering. The Kerr rotation loops showed high PMA and out-of-plane squareness (S{sub ⊥}) of ~0.9 were found in low base pressure chamber. Within high base pressure chamber, Co{sub 3}Pt films just show magnetic isotropy behaviors. This study provides a fabrication method for the preparation of high PMA HCP-type Co{sub 3}Pt films on the glass substrate without any underlayer at RT. The results could be the base for future development of RT-deposited magnetic alloy thin film with high PMA. - Highlights: • Fabricated high perpendicular magnetic anisotropy Co{sub 3}Pt thin film on glass substrate. • Prepared HCP Co{sub 3}Pt thin film at room temperature. • The key to enhance the PMA of the Co{sub 3}Pt films. • Thinner film is good to fabricate PMA Co{sub 3}Pt thin films.

  13. Achieving perpendicular anisotropy in half-metallic Heusler alloys for spin device applications

    Science.gov (United States)

    Munira, Kamaram; Romero, Jonathon; Butler, William H.

    2014-05-01

    Various full Heusler alloys are interfaced with MgO and the magnetic properties of the Heusler-MgO junctions are studied. Next to MgO, the cubic Heusler system distorts to a tetragonal one, thereby inducing an anisotropy. The half-metallicity and nature of anisotropy (in-plane or perpendicular) in the Heusler-MgO system is governed mostly by the interface Heusler layers. There is a trend that Mn-O bonding near the MgO-Heusler junction results in perpendicular anisotropy. The ability to remain half-metallic and have perpendicular anisotropy makes some of these alloys potential candidates as free-layers in Spin Transfer Torque Random Access Memory (STT-RAM) devices, particularly, Cr2MnAs-MgO system with MnAs interface layers and Co2MnSi-MgO system with Mn2 interface layers.

  14. Energy Conversion Mechanism for Electron Perpendicular Energy in High Guide-Field Reconnection

    Science.gov (United States)

    Guo, Xuehan; Horiuchi, Ritoku; Kaminou, Yasuhiro; Cheng, Frank; Ono, Yasushi

    2016-10-01

    The energy conversion mechanism for electron perpendicular energy, both the thermal and the kinetic energy, is investigated by means of two-dimensional, full-particle simulations in an open system. It is shown that electron perpendicular heating is mainly due to the breaking of magnetic moment conservation in separatrix region because the charge separation generates intense variation of electric field within the electron Larmor radius. Meanwhile, electron perpendicular acceleration takes place manly due to the polarization drift term as well as the curvature drift term of E . u⊥ in the downstream near the X-point. The enhanced electric field due to the charge separation there results in a significant effect of the polarization drift term on the dissipation of magnetic energy within the ion inertia length in the downstream. Japan Society for the Promotion of Science (JSPS) Fellows 15J03758.

  15. Secondary School Mathematics, Chapter 13, Perpendiculars and Parallels (I), Chapter 14, Similarity. Student's Text.

    Science.gov (United States)

    Stanford Univ., CA. School Mathematics Study Group.

    The first chapter of the seventh unit in this SMSG series discusses perpendiculars and parallels; topics covered include the relationship between parallelism and perpendicularity, rectangles, transversals, parallelograms, general triangles, and measurement of the circumference of the earth. The second chapter, on similarity, discusses scale…

  16. Influence of Moisture Content and Compression Axis on Physico-mechanical Properties of Shorea robusta Seeds

    Science.gov (United States)

    Shashikumar, C.; Pradhan, R. C.; Mishra, S.

    2018-02-01

    Shorea robusta (Sal) is mainly harvested and processed for its seed oil, which has diverse application in commercial food and non-food based industries. Before extraction of its oil, seeds undergo into various post-harvest unit operations. Physical and mechanical properties play an important role in the handling and other processing activity. In this study influence of moisture content and compression axis of sal seed on physico-mechanical properties were studied and their application are highlighted. The experiments were conducted at five different moisture levels of 6.38, 10.49, 13.63, 17.64, and 21.95% (d.b) at two different orientations. The first orientation is on major axis (LEN) of the seed, and the other orientation is on intermediate or minor axis (WID), which is right angle to the major axis. It was observed that 68% of sal seeds were of medium size group at initial moisture content of 10.49% (d.b). The mean length and width of sal seed was found to be 26.7 mm and 12.8 mm, respectively. It was found that values of hardness, deformation at hardness, deformation at hardness percentage and energy for rupture were higher in minor axis (WID) as compared to the major axis (LEN). The results provide necessary data that may be useful to engineers, scientists, industries in the design of a suitable post-harvest processing machine.

  17. Influence of Moisture Content and Compression Axis on Physico-mechanical Properties of Shorea robusta Seeds

    Science.gov (United States)

    Shashikumar, C.; Pradhan, R. C.; Mishra, S.

    2018-06-01

    Shorea robusta (Sal) is mainly harvested and processed for its seed oil, which has diverse application in commercial food and non-food based industries. Before extraction of its oil, seeds undergo into various post-harvest unit operations. Physical and mechanical properties play an important role in the handling and other processing activity. In this study influence of moisture content and compression axis of sal seed on physico-mechanical properties were studied and their application are highlighted. The experiments were conducted at five different moisture levels of 6.38, 10.49, 13.63, 17.64, and 21.95% (d.b) at two different orientations. The first orientation is on major axis (LEN) of the seed, and the other orientation is on intermediate or minor axis (WID), which is right angle to the major axis. It was observed that 68% of sal seeds were of medium size group at initial moisture content of 10.49% (d.b). The mean length and width of sal seed was found to be 26.7 mm and 12.8 mm, respectively. It was found that values of hardness, deformation at hardness, deformation at hardness percentage and energy for rupture were higher in minor axis (WID) as compared to the major axis (LEN). The results provide necessary data that may be useful to engineers, scientists, industries in the design of a suitable post-harvest processing machine.

  18. Family history study of the familial coaggregation of borderline personality disorder with axis I and nonborderline dramatic cluster axis II disorders.

    Science.gov (United States)

    Zanarini, Mary C; Barison, Leah K; Frankenburg, Frances R; Reich, D Bradford; Hudson, James I

    2009-08-01

    The purpose of this study was to assess the familial coaggregation of borderline personality disorder (BPD) with a full array of axis I disorders and four axis II disorders (antisocial personality disorder, histrionic personality disorder, narcissistic personality disorder, and sadistic personality disorder) in the first-degree relatives of borderline probands and axis II comparison subjects. Four hundred and forty-five inpatients were interviewed about familial psychopathology using the Revised Family History Questionnaire-a semistructured interview of demonstrated reliability. Of these 445 subjects, 341 met both DIB-R and DSM-III-R criteria for BPD and 104 met DSM-III-R criteria for another type of personality disorder (and neither criteria set for BPD). The psychopathology of 1,580 first-degree relatives of borderline probands and 472 relatives of axis II comparison subjects was assessed. Using structural models for familial coaggregation, it was found that BPD coaggregates with major depression, dysthymic disorder, bipolar I disorder, alcohol abuse/dependence, drug abuse/dependence, panic disorder, social phobia, obsessive-compulsive disorder, generalized anxiety disorder, posttraumatic stress disorder, somatoform pain disorder, and all four axis II disorders studied. Taken together, the results of this study suggest that common familial factors, particularly in the areas of affective disturbance and impulsivity, contribute to borderline personality disorder.

  19. Variations in the origin of inferior phrenic arteries and their relationship to celiac axis variations on CT angiography

    Energy Technology Data Exchange (ETDEWEB)

    Aslaner, Ramazan; Pekcevik, Yeliz; Sahin, Hilal [Dept. of Radiology, Tepecik Training and Research Hospital, Izmir (Turkmenistan); Toka, Onur [Dept. of Statistics, Hacettepe University, Ankara (Turkmenistan)

    2017-04-15

    Knowing the origin of the inferior phrenic artery (IPA) is important prior to surgical interventions and interventional radiological procedures related to IPA. We aimed to identify variations in the origin of IPA and to investigate the relationship between the origin of IPA and celiac axis variations using computed tomography angiography (CTA). The CTA images of 1000 patients (737 male and 263 female, the mean age 60, range 18–94 years) were reviewed in an analysis of IPA and celiac axis variations. The origin of IPA was divided into two groups, those originating as a common trunk and those originating independently without a truncus. The relationship between the origin of IPA and celiac axis variation was analyzed using Pearson's chi-square test. Both IPAs originated from a common trunk in 295 (29.5%) patients. From which the majority of the common trunk originated from the aorta. Contrastingly, the inferior phrenic arteries originated from different origins in 705 (70.5%) patients. The majority of the right inferior phrenic artery (RIPA) and the left inferior phrenic artery (LIPA) originated independently from the celiac axis. Variation in the celiac axis were detected in 110 (11%) patients. The origin of IPA was found to be significantly different in the presence of celiac axis variation. The majority of IPA originated from the aorta in patients with a common IPA trunk, while the majority of RIPA and LIPA originating from the celiac axis in patients without a common IPA trunk. Thus, the origin of IPA may widely differ in the presence of celiac axis variation.

  20. Variations in the origin of inferior phrenic arteries and their relationship to celiac axis variations on CT angiography

    International Nuclear Information System (INIS)

    Aslaner, Ramazan; Pekcevik, Yeliz; Sahin, Hilal; Toka, Onur

    2017-01-01

    Knowing the origin of the inferior phrenic artery (IPA) is important prior to surgical interventions and interventional radiological procedures related to IPA. We aimed to identify variations in the origin of IPA and to investigate the relationship between the origin of IPA and celiac axis variations using computed tomography angiography (CTA). The CTA images of 1000 patients (737 male and 263 female, the mean age 60, range 18–94 years) were reviewed in an analysis of IPA and celiac axis variations. The origin of IPA was divided into two groups, those originating as a common trunk and those originating independently without a truncus. The relationship between the origin of IPA and celiac axis variation was analyzed using Pearson's chi-square test. Both IPAs originated from a common trunk in 295 (29.5%) patients. From which the majority of the common trunk originated from the aorta. Contrastingly, the inferior phrenic arteries originated from different origins in 705 (70.5%) patients. The majority of the right inferior phrenic artery (RIPA) and the left inferior phrenic artery (LIPA) originated independently from the celiac axis. Variation in the celiac axis were detected in 110 (11%) patients. The origin of IPA was found to be significantly different in the presence of celiac axis variation. The majority of IPA originated from the aorta in patients with a common IPA trunk, while the majority of RIPA and LIPA originating from the celiac axis in patients without a common IPA trunk. Thus, the origin of IPA may widely differ in the presence of celiac axis variation

  1. Variations in the Origin of Inferior Phrenic Arteries and Their Relationship to Celiac Axis Variations on CT Angiography.

    Science.gov (United States)

    Aslaner, Ramazan; Pekcevik, Yeliz; Sahin, Hilal; Toka, Onur

    2017-01-01

    Knowing the origin of the inferior phrenic artery (IPA) is important prior to surgical interventions and interventional radiological procedures related to IPA. We aimed to identify variations in the origin of IPA and to investigate the relationship between the origin of IPA and celiac axis variations using computed tomography angiography (CTA). The CTA images of 1000 patients (737 male and 263 female, the mean age 60, range 18-94 years) were reviewed in an analysis of IPA and celiac axis variations. The origin of IPA was divided into two groups, those originating as a common trunk and those originating independently without a truncus. The relationship between the origin of IPA and celiac axis variation was analyzed using Pearson's chi-square test. Both IPAs originated from a common trunk in 295 (29.5%) patients. From which the majority of the common trunk originated from the aorta. Contrastingly, the inferior phrenic arteries originated from different origins in 705 (70.5%) patients. The majority of the right inferior phrenic artery (RIPA) and the left inferior phrenic artery (LIPA) originated independently from the celiac axis. Variation in the celiac axis were detected in 110 (11%) patients. The origin of IPA was found to be significantly different in the presence of celiac axis variation. The majority of IPA originated from the aorta in patients with a common IPA trunk, while the majority of RIPA and LIPA originating from the celiac axis in patients without a common IPA trunk. Thus, the origin of IPA may widely differ in the presence of celiac axis variation.

  2. Validation of an Actuator Line Model Coupled to a Dynamic Stall Model for Pitching Motions Characteristic to Vertical Axis Turbines

    International Nuclear Information System (INIS)

    Mendoza, Victor; Goude, Anders; Bachant, Peter; Wosnik, Martin

    2016-01-01

    Vertical axis wind turbines (VAWT) can be used to extract renewable energy from wind flows. A simpler design, low cost of maintenance, and the ability to accept flow from all directions perpendicular to the rotor axis are some of the most important advantages over conventional horizontal axis wind turbines (HAWT). However, VAWT encounter complex and unsteady fluid dynamics, which present significant modeling challenges. One of the most relevant phenomena is dynamic stall, which is caused by the unsteady variation of angle of attack throughout the blade rotation, and is the focus of the present study. Dynamic stall is usually used as a passive control for VAWT operating conditions, hence the importance of predicting its effects. In this study, a coupled model is implemented with the open-source CFD toolbox OpenFOAM for solving the Navier-Stokes equations, where an actuator line model and dynamic stall model are used to compute the blade loading and body force. Force coefficients obtained from the model are validated with experimental data of pitching airfoil in similar operating conditions as an H-rotor type VAWT. Numerical results show reasonable agreement with experimental data for pitching motion. (paper)

  3. Validation of an Actuator Line Model Coupled to a Dynamic Stall Model for Pitching Motions Characteristic to Vertical Axis Turbines

    Science.gov (United States)

    Mendoza, Victor; Bachant, Peter; Wosnik, Martin; Goude, Anders

    2016-09-01

    Vertical axis wind turbines (VAWT) can be used to extract renewable energy from wind flows. A simpler design, low cost of maintenance, and the ability to accept flow from all directions perpendicular to the rotor axis are some of the most important advantages over conventional horizontal axis wind turbines (HAWT). However, VAWT encounter complex and unsteady fluid dynamics, which present significant modeling challenges. One of the most relevant phenomena is dynamic stall, which is caused by the unsteady variation of angle of attack throughout the blade rotation, and is the focus of the present study. Dynamic stall is usually used as a passive control for VAWT operating conditions, hence the importance of predicting its effects. In this study, a coupled model is implemented with the open-source CFD toolbox OpenFOAM for solving the Navier-Stokes equations, where an actuator line model and dynamic stall model are used to compute the blade loading and body force. Force coefficients obtained from the model are validated with experimental data of pitching airfoil in similar operating conditions as an H-rotor type VAWT. Numerical results show reasonable agreement with experimental data for pitching motion.

  4. Wave and particle evolution downstream of quasi-perpendicular shocks

    Science.gov (United States)

    Mckean, M. E.; Omidi, N.; Krauss-Varban, D.; Karimabadi, H.

    1995-01-01

    Distributions of ions heated in quasi-perpendicular bow shocks have large perpendicular temperature anisotropies that provide free energy for the growth of Alfven ion cyclotron (AIC) and mirror waves. These modes are often obsreved in the Earth's magnetosheath. Using two-dimensional hybrid simulations, we show that these waves are produced near the shock front and convected downstream rather than being produced locally downstream. The wave activity reduces the proton anisotropy to magnetosheath levels within a few tens of gyroradii of the shock but takes significantly longer to reduce the anisotropy of He(++) ions. The waves are primarily driven by proton anisotropy and the dynamics of the helium ions is controlled by the proton waves. Downstream of high Mach number shocks, mirror waves compete effectively with AIC waves. Downstream of low Mach number shocks, AIC waves dominate.

  5. Current-induced magnetization switching in atom-thick tungsten engineered perpendicular magnetic tunnel junctions with large tunnel magnetoresistance.

    Science.gov (United States)

    Wang, Mengxing; Cai, Wenlong; Cao, Kaihua; Zhou, Jiaqi; Wrona, Jerzy; Peng, Shouzhong; Yang, Huaiwen; Wei, Jiaqi; Kang, Wang; Zhang, Youguang; Langer, Jürgen; Ocker, Berthold; Fert, Albert; Zhao, Weisheng

    2018-02-14

    Perpendicular magnetic tunnel junctions based on MgO/CoFeB structures are of particular interest for magnetic random-access memories because of their excellent thermal stability, scaling potential, and power dissipation. However, the major challenge of current-induced switching in the nanopillars with both a large tunnel magnetoresistance ratio and a low junction resistance is still to be met. Here, we report spin transfer torque switching in nano-scale perpendicular magnetic tunnel junctions with a magnetoresistance ratio up to 249% and a resistance area product as low as 7.0 Ω µm 2 , which consists of atom-thick W layers and double MgO/CoFeB interfaces. The efficient resonant tunnelling transmission induced by the atom-thick W layers could contribute to the larger magnetoresistance ratio than conventional structures with Ta layers, in addition to the robustness of W layers against high-temperature diffusion during annealing. The critical switching current density could be lower than 3.0 MA cm -2 for devices with a 45-nm radius.

  6. A model for precursor structure in supercritical perpendicular, collisionless shock waves

    International Nuclear Information System (INIS)

    Sherwell, D.; Cairns, R.A.

    1978-01-01

    Magnetosonic solitons may be given smooth increasing profiles by assuming the presence within the wave of a current distribution Jsub(y)(x) of trapped ions perpendicular to Bsub(z)(x) and the wave velocity Vsub(x). Suitable ions are found immediately upstream of perpendicular collisionless shock waves and these are coincident with the often observed 'foot' in magnetic field profiles of moderately supercritical shocks. The theory is applied to previous experiments by modelling Jsub(y)(x), where Jsub(y)(x) is observed, the profiles in the foot are reproduced and explained. Insight into a number of features of fast shocks is obtained. (author)

  7. Streamer discharges can move perpendicularly to the electric field

    NARCIS (Netherlands)

    Nijdam, S.; Takahashi, E.; Teunissen, J.; Ebert, U.

    2014-01-01

    Streamer discharges are a primary mode of electric breakdown in thunderstorms and high voltage technology; they are generally believed to grow along electric field lines. However, we here give experimental and numerical evidence that streamers can propagate nearly perpendicularly to the background

  8. High-resolution in-source laser spectroscopy in perpendicular geometry

    Energy Technology Data Exchange (ETDEWEB)

    Heinke, R., E-mail: reinhard.heinke@uni-mainz.de; Kron, T. [Universität Mainz, Institut für Physik (Germany); Raeder, S. [Helmholtz-Institut Mainz (Germany); Reich, T.; Schönberg, P. [Universität Mainz, Institut für Kernchemie (Germany); Trümper, M.; Weichhold, C.; Wendt, K. [Universität Mainz, Institut für Physik (Germany)

    2017-11-15

    Operation of the novel laser ion source unit LIST (Laser Ion Source and Trap), operating at the on-line radioactive ion beam facility ISOLDE at CERN allowed for the production of ultra-pure beams of exotic isotopes far-off stability as well as direct isobar-free laser spectroscopy, giving access to the study of atomic and nuclear properties of so far inaccessible nuclides. We present a specific upgrade and adaption of the LIST targeted for high resolution spectroscopy with a Doppler-reduced perpendicular atom - laser beam geometry. With this PI-LIST (Perpendicularly Illuminated Laser Ion Source and Trap) setup, experimental linewidths below 100 MHz could be demonstrated in optical laser spectroscopy off-line, applying a pulsed injection-locked high repetition rate Ti:sapphire laser. A dual repeller configuration ensured highest suppression of isobaric interferences and almost background-free measurements on small samples in the order of 10{sup 11} atoms.

  9. LUCIFER - a Monte Carlo for high-p/sub perpendicular/ /sub to/ photoproduction

    Energy Technology Data Exchange (ETDEWEB)

    Ingelman, G.; Weigend, A.

    1987-08-01

    For high-p/sub perpendicular/ /sub to/ interactions, perturbatively calculated matrix elements for the QED and QCD Compton processes, the photon-gluon fusion process and prompt meson production through the higher twist mechanism are used. Low-p/sub perpendicular/ /sub to/ events are treated as rho/sup 0/-nucleon interactions using a simple VDM approach. The Lund string model is used for the fragmentation of colour charged partons into final state hadrons such that complete events are simulated which facilitates easy comparison with any experimental observable. (orig).

  10. Molecular-dynamics simulation of lateral friction in contact-mode atomic force microscopy of alkane films: The role of molecular flexibility

    DEFF Research Database (Denmark)

    Soza, P.; Hansen, Flemming Yssing; Taub, H.

    2011-01-01

    than on a surface of molecules with the long axis perpendicular to the surface, in agreement with experimental results. A major dissipation mechanism is the molecular flexibility as manifested in the torsional motion about the molecules' C-C bonds. The generation of gauche defects as a result...

  11. Measurement of the single 100 diffraction line and evaluation of the average crystallite sizes along the fiber axis for mesophase-pitch-based carbon fiber P100

    International Nuclear Information System (INIS)

    Yoshida, Akira; Kaburagi, Yutaka; Hishiyama, Yoshihiro

    2007-01-01

    Mesophase-pitch-based carbon fiber P100 is known as a well-oriented carbon fiber in which the partially graphitized crystallites align along the fiber axis. The X-ray powder diffraction pattern for P100 measured by the X-ray diffractometer reveals the 100 diffraction line as a composite peak with the 101 diffraction line. The composite peak is usually not easy to separate into the component peaks of 100 and 101 lines. In the present article, a method to measure the single 100 diffraction line with the X-ray diffractometer using fiber samples of P100 has been developed. It has been found that there exist two types of crystallites oriented to their basal planes along the fiber axis in each of the P100 fibers; the Z-type crystallite with the zigzag boundary planes and the A-type crystallite with the armchair boundary planes, both of the boundary planes are perpendicular to the fiber axis. The average crystallite sizes along the fiber axis evaluated are 53 nm for the Z-type crystallites and 800 nm for the armchair crystallites. The average crystallite thickness for both types is about 120 nm. (author)

  12. Output factor determination for dose measurements in axial and perpendicular planes using a silicon strip detector

    Science.gov (United States)

    Abou-Haïdar, Z.; Bocci, A.; Alvarez, M. A. G.; Espino, J. M.; Gallardo, M. I.; Cortés-Giraldo, M. A.; Ovejero, M. C.; Quesada, J. M.; Arráns, R.; Prieto, M. Ruiz; Vega-Leal, A. Pérez; Nieto, F. J. Pérez

    2012-04-01

    In this work we present the output factor measurements of a clinical linear accelerator using a silicon strip detector coupled to a new system for complex radiation therapy treatment verification. The objective of these measurements is to validate the system we built for treatment verification. The measurements were performed at the Virgin Macarena University Hospital in Seville. Irradiations were carried out with a Siemens ONCOR™ linac used to deliver radiotherapy treatment for cancer patients. The linac was operating in 6 MV photon mode; the different sizes of the fields were defined with the collimation system provided within the accelerator head. The output factor was measured with the silicon strip detector in two different layouts using two phantoms. In the first, the active area of the detector was placed perpendicular to the beam axis. In the second, the innovation consisted of a cylindrical phantom where the detector was placed in an axial plane with respect to the beam. The measured data were compared with data given by a commercial treatment planning system. Results were shown to be in a very good agreement between the compared set of data.

  13. Channel modeling, signal processing and coding for perpendicular magnetic recording

    Science.gov (United States)

    Wu, Zheng

    With the increasing areal density in magnetic recording systems, perpendicular recording has replaced longitudinal recording to overcome the superparamagnetic limit. Studies on perpendicular recording channels including aspects of channel modeling, signal processing and coding techniques are presented in this dissertation. To optimize a high density perpendicular magnetic recording system, one needs to know the tradeoffs between various components of the system including the read/write transducers, the magnetic medium, and the read channel. We extend the work by Chaichanavong on the parameter optimization for systems via design curves. Different signal processing and coding techniques are studied. Information-theoretic tools are utilized to determine the acceptable region for the channel parameters when optimal detection and linear coding techniques are used. Our results show that a considerable gain can be achieved by the optimal detection and coding techniques. The read-write process in perpendicular magnetic recording channels includes a number of nonlinear effects. Nonlinear transition shift (NLTS) is one of them. The signal distortion induced by NLTS can be reduced by write precompensation during data recording. We numerically evaluate the effect of NLTS on the read-back signal and examine the effectiveness of several write precompensation schemes in combating NLTS in a channel characterized by both transition jitter noise and additive white Gaussian electronics noise. We also present an analytical method to estimate the bit-error-rate and use it to help determine the optimal write precompensation values in multi-level precompensation schemes. We propose a mean-adjusted pattern-dependent noise predictive (PDNP) detection algorithm for use on the channel with NLTS. We show that this detector can offer significant improvements in bit-error-rate (BER) compared to conventional Viterbi and PDNP detectors. Moreover, the system performance can be further improved by

  14. Timber beams loaded perpendicular to grain by multiple connections

    NARCIS (Netherlands)

    Leijten, A.J.M.; Schoenmakers, J.C.M.

    2014-01-01

    In timber structures, beams which are loaded perpendicular to grain by connections along the span may fail by splitting, resulting in the collapse of the beam. In the past, empirical, semi-empirical and fracture mechanical models have been developed aiming at predicting the splitting failure load.

  15. Treg cell-IgA axis in maintenance of host immune homeostasis with microbiota

    OpenAIRE

    Feng, Ting; Elson, Charles O.; Cong, Yingzi

    2010-01-01

    The intestine is the home to a vast diversity of microbiota and a complex of mucosal immune system. Multiple regulatory mechanisms control host immune responses to microbiota and maintain intestinal immune homeostasis. This mini review will provide evidence indicating a Treg cell-IgA axis and such axis playing a major role in maintenance of intestinal homeostasis.

  16. Tuning giant anomalous Hall resistance ratio in perpendicular Hall balance

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, J. Y.; Yang, G. [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); State Key Laboratory of Magnetism, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Wang, S. G., E-mail: sgwang@iphy.ac.cn, E-mail: ghyu@mater.ustb.edu.cn [State Key Laboratory of Magnetism, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Liu, J. L. [State Key Laboratory of Magnetism, Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Department of Physics, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Wang, R. M. [Department of Physics, Beijing University of Aeronautics and Astronautics, Beijing 100191 (China); Amsellem, E.; Kohn, A. [Department of Materials Engineering, Ilse Katz Institute for Nanoscale Science and Technology, Ben-Gurion University of the Negev, Beer-Sheva 84105 (Israel); Yu, G. H., E-mail: sgwang@iphy.ac.cn, E-mail: ghyu@mater.ustb.edu.cn [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China)

    2015-04-13

    Anomalous Hall effect at room temperature in perpendicular Hall balance with a core structure of [Pt/Co]{sub 4}/NiO/[Co/Pt]{sub 4} has been tuned by functional CoO layers, where [Pt/Co]{sub 4} multilayers exhibit perpendicular magnetic anisotropy. A giant Hall resistance ratio up to 69 900% and saturation Hall resistance (R{sub S}{sup P}) up to 2590 mΩ were obtained in CoO/[Pt/Co]{sub 4}/NiO/[Co/Pt]{sub 4}/CoO system, which is 302% and 146% larger than that in the structure without CoO layers, respectively. Transmission electron microscopy shows highly textured [Co/Pt]{sub 4} multilayers and oxide layers with local epitaxial relations, indicating that the crystallographic structure has significant influence on spin dependent transport properties.

  17. Kinetic structures of quasi-perpendicular shocks in global particle-in-cell simulations

    International Nuclear Information System (INIS)

    Peng, Ivy Bo; Markidis, Stefano; Laure, Erwin; Johlander, Andreas; Vaivads, Andris; Khotyaintsev, Yuri; Henri, Pierre; Lapenta, Giovanni

    2015-01-01

    We carried out global Particle-in-Cell simulations of the interaction between the solar wind and a magnetosphere to study the kinetic collisionless physics in super-critical quasi-perpendicular shocks. After an initial simulation transient, a collisionless bow shock forms as a result of the interaction of the solar wind and a planet magnetic dipole. The shock ramp has a thickness of approximately one ion skin depth and is followed by a trailing wave train in the shock downstream. At the downstream edge of the bow shock, whistler waves propagate along the magnetic field lines and the presence of electron cyclotron waves has been identified. A small part of the solar wind ion population is specularly reflected by the shock while a larger part is deflected and heated by the shock. Solar wind ions and electrons are heated in the perpendicular directions. Ions are accelerated in the perpendicular direction in the trailing wave train region. This work is an initial effort to study the electron and ion kinetic effects developed near the bow shock in a realistic magnetic field configuration

  18. Interaction of Mutually Perpendicular Magnetic Fields in HTSC

    Directory of Open Access Journals (Sweden)

    Vasilyev Aleksandr Fedorovich

    2015-11-01

    Full Text Available In this article a problem of interaction of the crossed magnetic fields in superconductors is considered. Superconducting materials have nonlinear magnetic properties. It allows using a non-linear magnetic susceptibility for measurement of feeble magnetic fields. We place a wire of superconducting material in a constant parallel uniform magnetic field. Then we let through a wire the alternating current leak. Interaction of mutual and perpendicular variation magnetic fields, with adequate accuracy is described by Ginzburg-Landau's equations. Approximate solution of the written equations is received. The component of a magnetic field parallel to a wire contains a variable component. Frequency of a variable component of the magnetic field is equal to the doubled current frequency. Amplitude of the variable component of the magnetic field is proportional to strength of the constant magnetic field. The experimental installation for research of interaction of mutually perpendicular magnetic fields is created. The cylinder from HTSC of ceramics of the YBa2Cu3O7-x was used as a sensor. Dependence of amplitude of the second harmonica of a variation magnetic field on strength of a constant magnetic field is received.

  19. Motion of a compact toroid inside a cylindrical flux conserver

    Energy Technology Data Exchange (ETDEWEB)

    Jarboe, T.R.; Henins, I.; Hoida, H.W.; Linford, R.K.; Marshall, J.; Platts, D.A.; Sherwood, A.R.

    1980-10-13

    Compact toroids have been generated in a cylindrical resistive flux conserver. They are observed to rotate so that their major axis is perpendicular to the axis of the flux conserver. Subsequently they remain stationary and their magnetic fields decay with a time constant of about 100 ..mu..s. This is the first observation of the predicted tipping mode and its saturation when no external fields are present. The compact toroids contain toroidal fields and are initially prolate in shape.

  20. Motion of a compact toroid inside a cylindrical flux conserver

    International Nuclear Information System (INIS)

    Jarboe, T.R.; Henins, I.; Hoida, H.W.; Linford, R.K.; Marshall, J.; Platts, D.A.; Sherwood, A.R.

    1980-01-01

    Compact toroids have been generated in a cylindrical resistive flux conserver. They are observed to rotate so that their major axis is perpendicular to the axis of the flux conserver. Subsequently they remain stationary and their magnetic fields decay with a time constant of about 100 μs. This is the first observation of the predicted tipping mode and its saturation when no external fields are present. The compact toroids contain toroidal fields and are initially prolate in shape

  1. In-plane and perpendicular exchange bias in [Pt/Co]/NiO multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Lin, K.W.; Guo, J.Y.; Chang, S.C.; Ouyang, H. [Department of Materials Science and Engineering, National Chung Hsing University, Taichung 402 (China); Kahwaji, S.; Van Lierop, J. [Department of Physics and Astronomy, University of Manitoba, Winnipeg, R3T 2N2 (Canada); Phuoc, N.N.; Suzuki, T. [Information Storage Materials Laboratory, Toyota Technological Institute, Nagoya 468-8511 (Japan)

    2007-12-15

    Exchange bias in [Pt/Co]/NiO multilayers were studied as a function of film thickness and [Pt/Co] layer repetition. A strong temperature dependence of the coercivity, H{sub c}, and exchange bias field, H{sub ex}, was observed for the thick and thinnest [Pt/Co]/NiO multilayers. While the thinnest [Pt(3 nm)/Co(1.25 nm)]{sub 4}/NiO multilayers exhibits no in-plane exchange bias field, a perpendicular H{sub ex} {sub perpendicular} {sub to} {proportional_to} -150 Oe at 80 K was measured. By contrast, the thickest [Pt(12 nm)/Co(10 nm)]{sub 1}/NiO multilayers exhibited an in-plane H{sub ex//}{proportional_to}-600 Oe (with H{sub ex//}{proportional_to}-1300 Oe at 5 K) with no measurable perpendicular exchange bias field. The estimated interfacial exchange coupling energy implies the effective Co layer thickness contributing to the exchange bias is effective only in Co layer in contact with NiO bottom layer. AC susceptibility and the temperature dependence of H{sub ex} show that the a 1.25 nm thick Co component enables perpendicular exchange bias with a reduced blocking temperature T{sub B}{proportional_to}200 K, compared to that (T{sub B}{proportional_to}250 K) for the thick [Pt/Co]/NiO multilayers. This is attributed to disordered CoPt phases that formed due to intermixing between Co and Pt during deposition. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. THE EFFECT OF INTERMITTENT GYRO-SCALE SLAB TURBULENCE ON PARALLEL AND PERPENDICULAR COSMIC-RAY TRANSPORT

    International Nuclear Information System (INIS)

    Le Roux, J. A.

    2011-01-01

    Earlier work based on nonlinear guiding center (NLGC) theory suggested that perpendicular cosmic-ray transport is diffusive when cosmic rays encounter random three-dimensional magnetohydrodynamic turbulence dominated by uniform two-dimensional (2D) turbulence with a minor uniform slab turbulence component. In this approach large-scale perpendicular cosmic-ray transport is due to cosmic rays microscopically diffusing along the meandering magnetic field dominated by 2D turbulence because of gyroresonant interactions with slab turbulence. However, turbulence in the solar wind is intermittent and it has been suggested that intermittent turbulence might be responsible for the observation of 'dropout' events in solar energetic particle fluxes on small scales. In a previous paper le Roux et al. suggested, using NLGC theory as a basis, that if gyro-scale slab turbulence is intermittent, large-scale perpendicular cosmic-ray transport in weak uniform 2D turbulence will be superdiffusive or subdiffusive depending on the statistical characteristics of the intermittent slab turbulence. In this paper we expand and refine our previous work further by investigating how both parallel and perpendicular transport are affected by intermittent slab turbulence for weak as well as strong uniform 2D turbulence. The main new finding is that both parallel and perpendicular transport are the net effect of an interplay between diffusive and nondiffusive (superdiffusive or subdiffusive) transport effects as a consequence of this intermittency.

  3. THE EFFECT OF INTERMITTENT GYRO-SCALE SLAB TURBULENCE ON PARALLEL AND PERPENDICULAR COSMIC-RAY TRANSPORT

    Energy Technology Data Exchange (ETDEWEB)

    Le Roux, J. A. [Department of Physics, University of Alabama in Huntsville, Huntsville, AL 35899 (United States)

    2011-12-10

    Earlier work based on nonlinear guiding center (NLGC) theory suggested that perpendicular cosmic-ray transport is diffusive when cosmic rays encounter random three-dimensional magnetohydrodynamic turbulence dominated by uniform two-dimensional (2D) turbulence with a minor uniform slab turbulence component. In this approach large-scale perpendicular cosmic-ray transport is due to cosmic rays microscopically diffusing along the meandering magnetic field dominated by 2D turbulence because of gyroresonant interactions with slab turbulence. However, turbulence in the solar wind is intermittent and it has been suggested that intermittent turbulence might be responsible for the observation of 'dropout' events in solar energetic particle fluxes on small scales. In a previous paper le Roux et al. suggested, using NLGC theory as a basis, that if gyro-scale slab turbulence is intermittent, large-scale perpendicular cosmic-ray transport in weak uniform 2D turbulence will be superdiffusive or subdiffusive depending on the statistical characteristics of the intermittent slab turbulence. In this paper we expand and refine our previous work further by investigating how both parallel and perpendicular transport are affected by intermittent slab turbulence for weak as well as strong uniform 2D turbulence. The main new finding is that both parallel and perpendicular transport are the net effect of an interplay between diffusive and nondiffusive (superdiffusive or subdiffusive) transport effects as a consequence of this intermittency.

  4. Characterization of CBD grown ZnO films with high c-axis orientation

    Energy Technology Data Exchange (ETDEWEB)

    Kahraman, S., E-mail: suleymanmku@gmail.com [Physics Department, Mustafa Kemal University, 31034 Hatay (Turkey); Bayansal, F.; Cetinkara, H.A.; Cakmak, H.M.; Gueder, H.S. [Physics Department, Mustafa Kemal University, 31034 Hatay (Turkey)

    2012-06-15

    Highly c-axis oriented ZnO films were deposited on seeded glass substrates. Successive ionic layer adsorption and reaction (SILAR) method and chemical bath deposition (CBD) method were used to obtain seed layers and ZnO films. To see the effects of seed layer and deposition time, structural (e.g. grain size, microstrain and dislocation density), morphological, and electrical (e.g. resistivity, activation energy) properties of the films were investigated by scanning electron microscopy, X-ray diffraction, and four point probe method. From the SEM images, resultant structures were found as well defined nanorods nearly perpendicular to the substrate surfaces and densely cover the substrates. The XRD patterns showed that ZnO films have hexagonal wurtzite structure with a preferred c-axis orientation along (002) plane. C-axis orientation was also supported by texture coefficient calculations. The lattice parameters of the structures were determined as a = 3.2268 A, b = 5.2745 A, {alpha} = {beta} = 90 Degree-Sign and {gamma} = 120 Degree-Sign . From the XRD patterns, it was revealed that, microstrain and dislocation density values of the structures decreased whereas grain size increased. This was attributed to enhancement occurred in lattice structure of the ZnO films. Activation energy values of the films were found in between 0.12 and 0.15 eV from the dark electrical resistivity-temperature characteristics in a temperature range of 300-500 K. - Highlights: Black-Right-Pointing-Pointer Hexagonal wurtzite structured ZnO nanorods (preferred orientation along (002) plane). Black-Right-Pointing-Pointer Electrical activation energies were calculated in between 0.12 and 0.15 eV. Black-Right-Pointing-Pointer Microstrain and dislocation density decreased with increasing deposition time. Black-Right-Pointing-Pointer Increasing deposition time was resulted in an increase in preferred orientation.

  5. Theoretical study on the perpendicular anisotropic magnetoresistance using Rashba-type ferromagnetic model

    Science.gov (United States)

    Yahagi, Y.; Miura, D.; Sakuma, A.

    2018-05-01

    We investigated the anisotropic magnetoresistance (AMR) effects in ferromagnetic-metal multi-layers stacked on non-magnetic insulators in the context of microscopic theory. We represented this situation with tight-binding models that included the exchange and Rashba fields, where the Rashba field was assumed to originate from spin-orbit interactions as junction effects with the insulator. To describe the AMR ratios, the DC conductivity was calculated based on the Kubo formula. As a result, we showed that the Rashba field induced both perpendicular and in-plane AMR effects and that the perpendicular AMR effect rapidly decayed with increasing film thickness.

  6. Hypothalamic-pituitary-adrenal (HPA) axis suppression after treatment with glucocorticoid therapy for childhood acute lymphoblastic leukaemia

    NARCIS (Netherlands)

    Gordijn, Maartje S.; Gemke, Reinoud J. B. J.; van Dalen, Elvira C.; Rotteveel, Joost; Kaspers, Gertjan J. L.

    2012-01-01

    Background Glucocorticoids play a major role in the treatment of acute lymphoblastic leukaemia (ALL). However, supraphysiological doses may cause suppression of the hypothalamic-pituitary-adrenal (HPA) axis. HPA axis suppression resulting in reduced cortisol response may cause an impaired stress

  7. Hypothalamic-pituitary-adrenal (HPA) axis suppression after treatment with glucocorticoid therapy for childhood acute lymphoblastic leukaemia

    NARCIS (Netherlands)

    Gordijn, Maartje S.; Rensen, Niki; Gemke, Reinoud J. B. J.; van Dalen, Elvira C.; Rotteveel, Joost; Kaspers, Gertjan J. L.

    2015-01-01

    Glucocorticoids play a major role in the treatment of acute lymphoblastic leukaemia (ALL). However, supraphysiological doses can suppress the hypothalamic-pituitary-adrenal (HPA) axis. HPA axis suppression resulting in reduced cortisol response may cause an impaired stress response and an inadequate

  8. Hypothalamic-pituitary-adrenal (HPA) axis suppression after treatment with glucocorticoid therapy for childhood acute lymphoblastic leukaemia

    NARCIS (Netherlands)

    Rensen, Niki; Gemke, Reinoud J. B. J.; van Dalen, Elvira C.; Rotteveel, Joost; Kaspers, Gertjan J. L.

    2017-01-01

    Glucocorticoids play a major role in the treatment of acute lymphoblastic leukaemia (ALL). However, supraphysiological doses can suppress the hypothalamic-pituitary-adrenal (HPA) axis. HPA axis suppression resulting in reduced cortisol response may cause an impaired stress response and an inadequate

  9. Nanoconstriction spin-Hall oscillator with perpendicular magnetic anisotropy

    Science.gov (United States)

    Divinskiy, B.; Demidov, V. E.; Kozhanov, A.; Rinkevich, A. B.; Demokritov, S. O.; Urazhdin, S.

    2017-07-01

    We experimentally study spin-Hall nano-oscillators based on [Co/Ni] multilayers with perpendicular magnetic anisotropy. We show that these devices exhibit single-frequency auto-oscillations at current densities comparable to those for in-plane magnetized oscillators. The demonstrated oscillators exhibit large magnetization precession amplitudes, and their oscillation frequency is highly tunable by the electric current. These features make them promising for applications in high-speed integrated microwave circuits.

  10. Switching a Perpendicular Ferromagnetic Layer by Competing Spin Currents

    Science.gov (United States)

    Ma, Qinli; Li, Yufan; Gopman, D. B.; Kabanov, Yu. P.; Shull, R. D.; Chien, C. L.

    2018-03-01

    An ultimate goal of spintronics is to control magnetism via electrical means. One promising way is to utilize a current-induced spin-orbit torque (SOT) originating from the strong spin-orbit coupling in heavy metals and their interfaces to switch a single perpendicularly magnetized ferromagnetic layer at room temperature. However, experimental realization of SOT switching to date requires an additional in-plane magnetic field, or other more complex measures, thus severely limiting its prospects. Here we present a novel structure consisting of two heavy metals that delivers competing spin currents of opposite spin indices. Instead of just canceling the pure spin current and the associated SOTs as one expects and corroborated by the widely accepted SOTs, such devices manifest the ability to switch the perpendicular CoFeB magnetization solely with an in-plane current without any magnetic field. Magnetic domain imaging reveals selective asymmetrical domain wall motion under a current. Our discovery not only paves the way for the application of SOT in nonvolatile technologies, but also poses questions on the underlying mechanism of the commonly believed SOT-induced switching phenomenon.

  11. Spin-orbit torques for current parallel and perpendicular to a domain wall

    International Nuclear Information System (INIS)

    Schulz, Tomek; Lee, Kyujoon; Karnad, Gurucharan V.; Alejos, Oscar; Martinez, Eduardo; Moretti, Simone; Hals, Kjetil M. D.; Garcia, Karin; Ravelosona, Dafiné; Vila, Laurent; Lo Conte, Roberto; Kläui, Mathias; Ocker, Berthold; Brataas, Arne

    2015-01-01

    We report field- and current-induced domain wall (DW) depinning experiments in Ta\\Co 20 Fe 60 B 20 \\MgO nanowires through a Hall cross geometry. While purely field-induced depinning shows no angular dependence on in-plane fields, the effect of the current depends crucially on the internal DW structure, which we manipulate by an external magnetic in-plane field. We show depinning measurements for a current sent parallel to the DW and compare its depinning efficiency with the conventional case of current flowing perpendicularly to the DW. We find that the maximum efficiency is similar for both current directions within the error bars, which is in line with a dominating damping-like spin-orbit torque (SOT) and indicates that no large additional torques arise for currents perpendicular to the DW. Finally, we find a varying dependence of the maximum depinning efficiency angle for different DWs and pinning levels. This emphasizes the importance of our full angular scans compared with previously used measurements for just two field directions (parallel and perpendicular to the DW) to determine the real torque strength and shows the sensitivity of the SOT to the precise DW structure and pinning sites

  12. Interface-engineered spin-dependent transport in perpendicular Co/Pt multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Shao-Long; Yang, Guang; Teng, Jiao, E-mail: tengjiao@mater.ustb.edu.cn; Guo, Qi-Xun; Li, Lei-Lei; Yu, Guang-Hua, E-mail: ghyu@mater.ustb.edu.cn

    2016-11-30

    Highlights: • The anomalous Hall effect in Co/Pt multilayers is studied. • Thermally stable AHE feature is obtained in [Pt/Co]{sub 3}/Ta/MgO multilayers. • Good thermal stability is due to enhanced side-jump and intrinsic contributions. - Abstract: The improvement of anomalous Hall effect (AHE) has been obtained through the introduction of a Ta metallic layer at the Co/MgO interface in perpendicular [Pt/Co]{sub 3}/MgO multilayers. It is exhibited that the saturation anomalous Hall resistivity is 42% larger than that in Co/Pt multilayers without Ta insertion. More meaningfully, thermally stable AHE feature is gained in perpendicular [Pt/Co]{sub 3}/Ta/MgO multilayers despite Co-Pt interdiffusion. The AHE is enhanced for sample [Pt/Co]{sub 3}/Ta/MgO after annealing, mainly due to the enhancement of the side-jump and intrinsic contributions.

  13. Nano-patterning of perpendicular magnetic recording media by low-energy implantation of chemically reactive ions

    International Nuclear Information System (INIS)

    Martin-Gonzalez, M.S.; Briones, F.; Garcia-Martin, J.M.; Montserrat, J.; Vila, L.; Faini, G.; Testa, A.M.; Fiorani, D.; Rohrmann, H.

    2010-01-01

    Magnetic nano-patterning of perpendicular hard disk media with perpendicular anisotropy, but preserving disk surface planarity, is presented here. Reactive ion implantation is used to locally modify the chemical composition (hence the magnetization and magnetic anisotropy) of the Co/Pd multilayer in irradiated areas. The procedure involves low energy, chemically reactive ion irradiation through a resist mask. Among N, P and As ions, P are shown to be most adequate to obtain optimum bit density and topography flatness for industrial Co/Pd multilayer media. The effect of this ion contributes to isolate perpendicular bits by destroying both anisotropy and magnetic exchange in the irradiated areas. Low ion fluences are effective due to the stabilization of atomic displacement levels by the chemical effect of covalent impurities.

  14. Perpendicular exchange coupling effects in ferrimagnetic TbFeCo/GdFeCo hard/soft structures

    Science.gov (United States)

    Wang, Ke; Wang, Yahong; Ling, Fujin; Xu, Zhan

    2018-04-01

    Bilayers consisting of magnetically hard TbFeCo and soft GdFeCo alloy were fabricated. Exchange-spring and sharp switching in a step-by-step fashion were observed in the TbFeCo/GdFeCo hard/soft bilayers with increasing GdFeCo thickness. A perpendicular exchange bias field of several hundred Oersteds is observed from the shift of minor loops pinned by TbFeCo layer. The perpendicular exchange energy is derived to be in the range of 0.18-0.30 erg/cm2. The exchange energy is shown to increase with the thickness of GdFeCo layer in the bilayers, which can be attributed to the enhanced perpendicular anisotropy of GdFeCo layer in our experimental range.

  15. Perpendicular magnetic anisotropy in Co{sub X}Pd{sub 100−X} alloys for magnetic tunnel junctions

    Energy Technology Data Exchange (ETDEWEB)

    Clark, B.D.; Natarajarathinam, A.; Tadisina, Z.R. [Center for Materials for Information Technology, University of Alabama, Tuscaloosa, AL 35487 (United States); Chen, P.J.; Shull, R.D. [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Gupta, S., E-mail: Sgupta@eng.ua.edu [Center for Materials for Information Technology, University of Alabama, Tuscaloosa, AL 35487 (United States)

    2017-08-15

    Highlights: • CoPd alloy perpendicular anisotropy dependent on composition and thickness. • CIPT results show that TMR tracks with PMA of CoPd. • Potential replacement for Co/Pd multilayers. - Abstract: CoFeB/MgO-based perpendicular magnetic tunnel junctions (p-MTJ’s) with high anisotropy and low damping are critical for spin-torque transfer random access memory (STT-RAM). Most schemes of making the pinned CoFeB fully perpendicular require ferrimagnets with high damping constants, a high temperature-grown L1{sub 0} alloy, or an overly complex multilayered synthetic antiferromagnet (SyAF). We report a compositional study of perpendicular Co{sub x}Pd alloy-pinned Co{sub 20}Fe{sub 60}B{sub 20}/MgO based MTJ stacks, grown at moderate temperatures in a planetary deposition system. The perpendicular anisotropy of the Co{sub x}Pd alloy films can be tuned based on the layer thickness and composition. The films were characterized by alternating gradient magnetometry (AGM), energy-dispersive X-rays (EDX), and X-ray diffraction (XRD). Current-in-plane tunneling (CIPT) measurements have also been performed on the compositionally varied Co{sub x}Pd MTJ stacks. The Co{sub x}Pd alloy becomes fully perpendicular at approximately x = 30% (atomic fraction) Co. Full-film MTJ stacks of Si/SiO{sub 2}/MgO (13)/Co{sub X}Pd{sub 100−x} (50)/Ta (0.3)/CoFeB (1)/MgO (1.6)/CoFeB (1)/Ta (5)/Ru (10), with the numbers enclosed in parentheses being the layer thicknesses in nm, were sputtered onto thermally oxidized silicon substrates and in-situ lamp annealed at 400 °C for 5 min. CIPT measurements indicate that the highest TMR is observed for the CoPd composition with the highest perpendicular magnetic anisotropy.

  16. Modeling of Geometric Error in Linear Guide Way to Improved the vertical three-axis CNC Milling machine’s accuracy

    Science.gov (United States)

    Kwintarini, Widiyanti; Wibowo, Agung; Arthaya, Bagus M.; Yuwana Martawirya, Yatna

    2018-03-01

    The purpose of this study was to improve the accuracy of three-axis CNC Milling Vertical engines with a general approach by using mathematical modeling methods of machine tool geometric errors. The inaccuracy of CNC machines can be caused by geometric errors that are an important factor during the manufacturing process and during the assembly phase, and are factors for being able to build machines with high-accuracy. To improve the accuracy of the three-axis vertical milling machine, by knowing geometric errors and identifying the error position parameters in the machine tool by arranging the mathematical modeling. The geometric error in the machine tool consists of twenty-one error parameters consisting of nine linear error parameters, nine angle error parameters and three perpendicular error parameters. The mathematical modeling approach of geometric error with the calculated alignment error and angle error in the supporting components of the machine motion is linear guide way and linear motion. The purpose of using this mathematical modeling approach is the identification of geometric errors that can be helpful as reference during the design, assembly and maintenance stages to improve the accuracy of CNC machines. Mathematically modeling geometric errors in CNC machine tools can illustrate the relationship between alignment error, position and angle on a linear guide way of three-axis vertical milling machines.

  17. Perpendicular diffusion of a dilute beam of charged dust particles in a strongly coupled dusty plasma

    Science.gov (United States)

    Liu, Bin; Goree, J.

    2014-06-01

    The diffusion of projectiles drifting through a target of strongly coupled dusty plasma is investigated in a simulation. A projectile's drift is driven by a constant force F. We characterize the random walk of the projectiles in the direction perpendicular to their drift. The perpendicular diffusion coefficient Dp⊥ is obtained from the simulation data. The force dependence of Dp⊥ is found to be a power law in a high force regime, but a constant at low forces. A mean kinetic energy Wp for perpendicular motion is also obtained. The diffusion coefficient is found to increase with Wp with a linear trend at higher energies, but an exponential trend at lower energies.

  18. Can QCD be tested in high-energy low-p/sub perpendicular to / hadronic physics?

    CERN Document Server

    Predazzi, Enrico

    1982-01-01

    It is suggested that the broadening of the p/sub perpendicular to / distribution which is predicted by QCD and which has been seen in e ^{+}e^{-} at highest PETRA energies should be reached in low-p /sub perpendicular to / proton-proton collisions (using the technique of removal of the leading-particle effect) at c.m. energies \\sqrt{s}>or=400 GeV. The preliminary data from the pp Cern collider support this estimate, which agrees with cosmic-ray analysis.

  19. In situ synchrotron X-ray diffraction of ferroelastic La0.8Ca0.2CoO3 ceramics during uniaxial compression

    International Nuclear Information System (INIS)

    Vullum, Per Erik; Mastin, Johann; Wright, Jonathan; Einarsrud, Mari-Ann; Holmestad, Randi; Grande, Tor

    2006-01-01

    Uniaxial compression of rhombohedral La 0.8 Ca 0.2 CoO 3 ceramics has been studied in situ using synchrotron X-ray diffraction. The intensities of Bragg reflections parallel and perpendicular to the stress field were simultaneously detected as a function of the stress. Reorientation of ferroelastic domains due to the uniaxial stress was demonstrated. With increasing stress the volume fraction of domains with the hexagonal c-axis parallel to the stress axis increased at the expense of domains with the c-axis perpendicular to the stress axis. The strain in the polycrystalline materials evolved unevenly with increasing stress due to crystallographic anisotropy. In energetically favourable domains with the c-axis parallel to the stress axis, the rhombohedral distortion from cubic symmetry increased, while the crystal structure became closer to cubic in domains with the c-axis perpendicular to the stress. Successive compression/decompression cycles to higher maximum stress resulted in a higher volume fraction of reoriented domains both at maximum stress and after decompression

  20. An improved computer controlled triple-axis neutron spectrometer

    International Nuclear Information System (INIS)

    Cooper, M.J.; Hall, J.W.; Hutchings, M.T.

    1975-07-01

    A description is given of the computer-controlled triple-axis neutron spectrometer installed at the PLUTO reactor at Harwell. The reasons for an nature of recent major improvements are discussed. Following a general description of the spectrometer, details are then given of the new computerised control system, including the functions of the various programs which are now available to the user. (author)

  1. Exchange bias energy in Co/Pt/IrMn multilayers with perpendicular and in-plane anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Czapkiewicz, M. [Department of Electronics, AGH University of Science and Technology, 30-059 Cracow (Poland)]. E-mail: czapkiew@agh.edu.pl; Stobiecki, T. [Department of Electronics, AGH University of Science and Technology, 30-059 Cracow (Poland); Rak, R. [Department of Electronics, AGH University of Science and Technology, 30-059 Cracow (Poland); Zoladz, M. [Department of Electronics, AGH University of Science and Technology, 30-059 Cracow (Poland); Dijken, S. van [CRANN and School of Physics, Trinity College, Dublin 2 (Ireland)

    2007-09-15

    The magnetization reversal process in perpendicularly biased [Pt/Co]{sub 3}/d{sub Pt} Pt/IrMn and in-plane biased Co/d{sub Pt} Pt/IrMn multilayers with 0nm=perpendicular magnetic anisotropy, on the other hand, exhibit maximum exchange bias and minimum coercivity for d{sub Pt}=0.1nm. In both cases, the existence of large exchange bias fields correlates with a high domain density during magnetization reversal. The interface exchange coupling energy is larger for the in-plane biased films than for the perpendicularly biased multilayers.

  2. Triple differential cross-sections of Ne (2s2) in coplanar to perpendicular plane geometry

    Science.gov (United States)

    Chen, L. Q.; Khajuria, Y.; Chen, X. J.; Xu, K. Z.

    2003-10-01

    The distorted wave Born approximation (DWBA) with the spin averaged static exchange potential has been used to calculate the triple differential cross-sections (TDCSs) for Ne (2s^2) ionization by electron impact in coplanar to perpendicular plane symmetric geometry at 110.5 eV incident electron energy. The present theoretical results at gun angles Psi = 0^circ (coplanar symmetric geometry) and Psi = 90^circ (perpendicular plane geometry) are in satisfactory agreement with the available experimental data. A deep interference minimum appears in the TDCS in the coplanar symmetric geometry and a strong peak at scattering angle xi = 90^circ caused by the single collision mechanism has been observed in the perpendicular plane geometry. The TDCSs at the gun angles Psi = 30^circ, and Psi = 60^circ are predicted.

  3. A broadband two axis flux-gate magnetometer

    Directory of Open Access Journals (Sweden)

    P. Palangio

    1998-06-01

    Full Text Available A broadband two axis flux-gate magnetometer was developed to obtain high sensitivity in magnetotelluric measurements. In magnetotelluric sounding, natural low frequency electromagnetic fields are used to estimate the conductivity of the Earth's interior. Because variations in the natural magnetic field have small amplitude(10-100 pT in the frequency range 1 Hz to 100 Hz, highly sensitive magnetic sensors are required. In magnetotelluric measurements two long and heavy solenoids, which must be installed, in the field station, perpendicular to each other (north-south and east-west and levelled in the horizontal plane are used. The coil is a critical component in magnetotelluric measurements because very slight motions create noise voltages, particularly troublesome in wooded areas; generally the installation takes place in a shallow trench. Moreover the coil records the derivative of the variations rather than the magnetic field variations, consequently the transfer function (amplitude and phase of this sensor is not constant throughout the frequency range 0.001-100 Hz. The instrument, developed at L'Aquila Geomagnetic Observatory, has a flat response in both amplitude and phase in the frequency band DC-100 Hz, in addition it has low weight, low power, small volume and it is easier to install in the field than induction magnetometers. The sensivity of this magnetometer is 10 pT rms.

  4. Spin-orbit torques for current parallel and perpendicular to a domain wall

    Energy Technology Data Exchange (ETDEWEB)

    Schulz, Tomek; Lee, Kyujoon; Karnad, Gurucharan V. [Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudinger Weg 7, 55128 Mainz (Germany); Alejos, Oscar [Departamento de Electricidad y Electrónica, Universidad de Valladolid, Paseo de Belen, 7, E-47011 Valladolid (Spain); Martinez, Eduardo; Moretti, Simone [Departamento Fisica Aplicada, Universidad de Salamanca, Plaza de los Caidos s/n, E-38008 Salamanca (Spain); Hals, Kjetil M. D. [Niels Bohr International Academy and the Center for Quantum Devices, Niels Bohr Institute, University of Copenhagen, 2100 Copenhagen (Denmark); Garcia, Karin; Ravelosona, Dafiné [Institut d' Electronique Fondamentale, UMR CNRS 8622, Université Paris Sud, 91405 Orsay Cedex (France); Vila, Laurent [Institut Nanosciences et Cryogénie, Université Grenoble Alpes, F-38000 Grenoble (France); Institut Nanosciences et Cryogénie, CEA, F-38000 Grenoble (France); Lo Conte, Roberto; Kläui, Mathias [Institut für Physik, Johannes Gutenberg-Universität Mainz, Staudinger Weg 7, 55128 Mainz (Germany); Graduate School of Excellence “Materials Science in Mainz” (MAINZ), Staudinger Weg 9, 55128 Mainz (Germany); Ocker, Berthold [Singulus Technologies AG, 63796 Kahl am Main (Germany); Brataas, Arne [Department of Physics, Norwegian University of Science and Technology, NO-7491 Trondheim (Norway)

    2015-09-21

    We report field- and current-induced domain wall (DW) depinning experiments in Ta\\Co{sub 20}Fe{sub 60}B{sub 20}\\MgO nanowires through a Hall cross geometry. While purely field-induced depinning shows no angular dependence on in-plane fields, the effect of the current depends crucially on the internal DW structure, which we manipulate by an external magnetic in-plane field. We show depinning measurements for a current sent parallel to the DW and compare its depinning efficiency with the conventional case of current flowing perpendicularly to the DW. We find that the maximum efficiency is similar for both current directions within the error bars, which is in line with a dominating damping-like spin-orbit torque (SOT) and indicates that no large additional torques arise for currents perpendicular to the DW. Finally, we find a varying dependence of the maximum depinning efficiency angle for different DWs and pinning levels. This emphasizes the importance of our full angular scans compared with previously used measurements for just two field directions (parallel and perpendicular to the DW) to determine the real torque strength and shows the sensitivity of the SOT to the precise DW structure and pinning sites.

  5. Vertical-axis turbine/propeller for ship propulsion

    Energy Technology Data Exchange (ETDEWEB)

    Barkla, H.M.

    1984-01-01

    There are so many variables in the design and operating conditions of a vertical-axis turbine/propeller for the propulsion of a ship by wind that a preliminary study is offered, based on two simplified models. Study of a linear motion of blades in air and water shows optimum conditions for blade-speed and blade-incidence. Analysis of the second, cyclical model is simplified by the assumption of constant angles of incidence. While the logical superiority of the vertical-axis system, with its low transmission loss, may not alone give it the advantage over all other systems in upwind and downwind sailing, there are indications that in the beam wind it is in a class of its own; the Voith-Schneider-Type propeller then produces a thrust with a major component to windward, so that the combined unit leaves little or no athwartships force.

  6. OD Covariance in Conjunction Assessment: Introduction and Issues

    Science.gov (United States)

    Hejduk, M. D.; Duncan, M.

    2015-01-01

    Primary and secondary covariances combined and projected into conjunction plane (plane perpendicular to relative velocity vector at TCA) Primary placed on x-axis at (miss distance, 0) and represented by circle of radius equal to sum of both spacecraft circumscribing radiiZ-axis perpendicular to x-axis in conjunction plane Pc is portion of combined error ellipsoid that falls within the hard-body radius circle

  7. DRIFT-INDUCED PERPENDICULAR TRANSPORT OF SOLAR ENERGETIC PARTICLES

    International Nuclear Information System (INIS)

    Marsh, M. S.; Dalla, S.; Kelly, J.; Laitinen, T.

    2013-01-01

    Drifts are known to play a role in galactic cosmic ray transport within the heliosphere and are a standard component of cosmic ray propagation models. However, the current paradigm of solar energetic particle (SEP) propagation holds the effects of drifts to be negligible, and they are not accounted for in most current SEP modeling efforts. We present full-orbit test particle simulations of SEP propagation in a Parker spiral interplanetary magnetic field (IMF), which demonstrate that high-energy particle drifts cause significant asymmetric propagation perpendicular to the IMF. Thus in many cases the assumption of field-aligned propagation of SEPs may not be valid. We show that SEP drifts have dependencies on energy, heliographic latitude, and charge-to-mass ratio that are capable of transporting energetic particles perpendicular to the field over significant distances within interplanetary space, e.g., protons of initial energy 100 MeV propagate distances across the field on the order of 1 AU, over timescales typical of a gradual SEP event. Our results demonstrate the need for current models of SEP events to include the effects of particle drift. We show that the drift is considerably stronger for heavy ion SEPs due to their larger mass-to-charge ratio. This paradigm shift has important consequences for the modeling of SEP events and is crucial to the understanding and interpretation of in situ observations

  8. Gut Microbiota-brain Axis

    Institute of Scientific and Technical Information of China (English)

    Hong-Xing Wang; Yu-Ping Wang

    2016-01-01

    Objective:To systematically review the updated information about the gut microbiota-brain axis.Data Sources:All articles about gut microbiota-brain axis published up to July 18,2016,were identified through a literature search on PubMed,ScienceDirect,and Web of Science,with the keywords of"gut microbiota","gut-brain axis",and "neuroscience".Study Selection:All relevant articles on gut microbiota and gut-brain axis were included and carefully reviewed,with no limitation of study design.Results:It is well-recognized that gut microbiota affects the brain's physiological,behavioral,and cognitive functions although its precise mechanism has not yet been fully understood.Gut microbiota-brain axis may include gut microbiota and their metabolic products,enteric nervous system,sympathetic and parasympathetic branches within the autonomic nervous system,neural-immune system,neuroendocrine system,and central nervous system.Moreover,there may be five communication routes between gut microbiota and brain,including the gut-brain's neural network,neuroendocrine-hypothalamic-pituitary-adrenal axis,gut immune system,some neurotransmitters and neural regulators synthesized by gut bacteria,and barrier paths including intestinal mucosal barrier and blood-brain barrier.The microbiome is used to define the composition and functional characteristics of gut microbiota,and metagenomics is an appropriate technique to characterize gut microbiota.Conclusions:Gut microbiota-brain axis refers to a bidirectional information network between the gut microbiota and the brain,which may provide a new way to protect the brain in the near future.

  9. The neuro-immune axis: Prospect for novel treatments for mental disorders

    NARCIS (Netherlands)

    Kraneveld, Aletta D.; de Theije, Caroline G.M.; van Heesch, Floor; Borre, Yuliya; de Kivit, Sander; Olivier, Berend; Korte, Mechiel; Garssen, Johan

    2014-01-01

    Disturbed bidirectional pathways between the (central) nervous system and immune system have been implicated in various mental disorders, including depressive and neurodevelopmental disorders. In this minireview, the role of the neuro-immune axis and its targetability in relation to major depression

  10. Exchange bias energy in Co/Pt/IrMn multilayers with perpendicular and in-plane anisotropy

    International Nuclear Information System (INIS)

    Czapkiewicz, M.; Stobiecki, T.; Rak, R.; Zoladz, M.; Dijken, S. van

    2007-01-01

    The magnetization reversal process in perpendicularly biased [Pt/Co] 3 /d Pt Pt/IrMn and in-plane biased Co/d Pt Pt/IrMn multilayers with 0nm= Pt = Pt =0.1nm. In both cases, the existence of large exchange bias fields correlates with a high domain density during magnetization reversal. The interface exchange coupling energy is larger for the in-plane biased films than for the perpendicularly biased multilayers

  11. Particle acceleration at quasi-perpendicular shock waves: Theory and observations at 1 AU

    International Nuclear Information System (INIS)

    Parker, L. Neergaard; Zank, G. P.; Hu, Q.

    2014-01-01

    The injection of particles into the diffusive shock acceleration mechanism at highly perpendicular (where θ Bn > 70°) interplanetary shocks is investigated. This extends the previous study of Neergaard Parker and Zank which focused on the injection problem at quasi-parallel interplanetary shocks. We use observations at 1 AU to construct upstream Maxwellian and κ-distributions that are then diffusively accelerated by the shock, thus yielding the downstream accelerated particle distribution. We compare the theoretical accelerated particle distribution to observations at 1 AU using Advanced Composition Explorer data. We classify our results for quasi-perpendicular shocks into three subcategories: those with ratios of the theoretical spectral index to observed power law of >1, ∼ 1, and <1, and compare the magnetic power spectral density plots of these categories. We find that in general the assumed upstream particle distribution that best fits the energetic particle observations is best represented by a κ-distribution, with κ = 4. The magnetic field fluctuations were representative of quasi-perpendicular shocks and showed no particular bias toward our spectral ratio subcategories. The subcategory with spectral ratio <0.9 yielded the largest injection energies for all groups. In all but two of the cases in this study, there were enough particles in the solar wind thermal core to account for the accelerated distribution, thereby giving a lower limit to the required injection energy needed to diffusively accelerate particles at a quasi-perpendicular interplanetary shock. In the remaining two cases, an additional population of particles was required to match the appropriate amplitude of the spectral index. For these cases, we used a low energy (1-50 keV) v –5 spectrum advocated by Fisk and Gloeckler.

  12. Gun-generated compact tori at Los Alamos

    International Nuclear Information System (INIS)

    Jarboe, T.R.; Henins, I.; Hoida, H.W.; Linford, R.K.; Marshall, J.; Platts, D.A.; Sherwood, A.R.

    1982-01-01

    We have generated compact toroids which can be made to come to rest in a cylindrical resistive flux conserver. They are observed to rotate so that their major axis is perpendicular to the axis of the flux conserver. Subsequently they appear to remain stationary and decay with a time constant of about 100 μs. We have also generated compact toroids in an oblate geometry which remain aligned with the axis of the flux conserver and decay with a time constant of 150 μs. The magnetic field reconnection time for compact toroid formation is measured in the latter case to be much shorter than the decay time

  13. Production of field-reversed configurations with a magnetized coaxial plasma gun

    Energy Technology Data Exchange (ETDEWEB)

    Jarboe, T.R.; Henins, I.; Hoida, H.W.; Linford, R.K.; Marshali, J.; Platts, D.A.; Sherwood, A.R.

    1980-01-01

    Compact toroids were generated which can be made to come to rest in a cylindrical resistive flux conserver. They are observed to rotate so that their major axis is perpendicular to the axis of the flux conserver. Subsequently they appear to remain stationary and decay with a time constant of about 100 ..mu..s. We have also generated compact toroids in an oblate geometry which remain aligned with the axis of the flux conserver and decay with a time constant of 150 ..mu..s. The magnetic field reconnection time for compact toroid formation is measured in the latter case to be much shorter than the decay time.

  14. Production of field-reversed configurations with a magnetized coaxial plasma gun

    International Nuclear Information System (INIS)

    Jarboe, T.R.; Henins, I.; Hoida, H.W.; Linford, R.K.; Marshali, J.; Platts, D.A.; Sherwood, A.R.

    1980-01-01

    Compact toroids were generated which can be made to come to rest in a cylindrical resistive flux conserver. They are observed to rotate so that their major axis is perpendicular to the axis of the flux conserver. Subsequently they appear to remain stationary and decay with a time constant of about 100 μs. We have also generated compact toroids in an oblate geometry which remain aligned with the axis of the flux conserver and decay with a time constant of 150 μs. The magnetic field reconnection time for compact toroid formation is measured in the latter case to be much shorter than the decay time

  15. Update on stress and depression: the role of the hypothalamic-pituitary-adrenal (HPA axis

    Directory of Open Access Journals (Sweden)

    Mello Andrea de Abreu Feijó de

    2003-01-01

    Full Text Available Over the past 50 years, relationships between stress and the neurobiological changes seen in psychiatric disorders have been well-documented. A major focus of investigations in this area has been the role of the hypothalamic-pituitary-adrenal (HPA axis, both as a marker of stress response and as a mediator of additional downstream pathophysiologic changes. This review examines the emerging literature concerning the relationship between stress, HPA axis function, and depression, as well as the role of early life stress as an important risk factor for HPA axis dysregulation. The more recent studies reviewed suggest that the prominence of HPA axis hyperactivity in adults with depressive and anxiety disorders may constitute a link between the occurrence of adversity in childhood and the development of adult psychopathology

  16. Tearing modes induced by perpendicular electron cyclotron resonance heating in the KSTAR tokamak

    Science.gov (United States)

    Lee, H. H.; Lee, S. G.; Seol, J.; Aydemir, A. Y.; Bae, C.; Yoo, J. W.; Na, Y. S.; Kim, H. S.; Woo, M. H.; Kim, J.; Joung, M.; You, K. I.; Park, B. H.

    2014-10-01

    This paper reports on experimental evidence that shows perpendicular electron cyclotron resonance heating (ECRH) can trigger classical tearing modes when deposited near a rational flux surface. The complex evolution of an m = 2 island is followed during current ramp-up in KSTAR plasmas, from its initial onset as the rational surface enters the ECRH resonance layer to its eventual lock on the wall after the rational surface leaves the layer. Stability analysis coupled to a transport calculation of the current profile with ECRH shows that the perpendicular ECRH may play a significant role in triggering and destabilizing classical m = 2 tearing modes, in agreement with our experimental observation.

  17. VizieR Online Data Catalog: Broad Hβ emission line in 102 Seyfert galaxies (Runco+, 2016)

    Science.gov (United States)

    Runco, J. N.; Cosens, M.; Bennert, V. N.; Scott, B.; Komossa, S.; Malkan, M. A.; Lazarova, M. S.; Auger, M. W.; Treu, T.; Park, D.

    2018-02-01

    A sample of 102 local (0.02=Kast spectrograph and 60 minutes total exposure time per object. The slit was aligned either along the major axis or perpendicular to it. 1D spectra were extracted using a 4 pixel (~3") width centered on the peak flux to mimic the 3" diameter circular fiber of SDSS. (2 data files).

  18. Measurements of isocenter path characteristics of the gantry rotation axis with a smartphone application

    International Nuclear Information System (INIS)

    Schiefer, H.; Peters, S.; Plasswilm, L.; Ingulfsen, N.; Kluckert, J.

    2015-01-01

    Purpose: For stereotactic radiosurgery, the AAPM Report No. 54 [AAPM Task Group 42 (AAPM, 1995)] requires the overall stability of the isocenter (couch, gantry, and collimator) to be within a 1 mm radius. In reality, a rotating system has no rigid axis and thus no isocenter point which is fixed in space. As a consequence, the isocenter concept is reviewed here. It is the aim to develop a measurement method following the revised definitions. Methods: The mechanical isocenter is defined here by the point which rotates on the shortest path in the room coordinate system. The path is labeled as “isocenter path.” Its center of gravity is assumed to be the mechanical isocenter. Following this definition, an image-based and radiation-free measurement method was developed. Multiple marker pairs in a plane perpendicular to the assumed gantry rotation axis of a linear accelerator are imaged with a smartphone application from several rotation angles. Each marker pair represents an independent measuring system. The room coordinates of the isocenter path and the mechanical isocenter are calculated based on the marker coordinates. The presented measurement method is by this means strictly focused on the mechanical isocenter. Results: The measurement result is available virtually immediately following completion of measurement. When 12 independent measurement systems are evaluated, the standard deviations of the isocenter path points and mechanical isocenter coordinates are 0.02 and 0.002 mm, respectively. Conclusions: The measurement is highly accurate, time efficient, and simple to adapt. It is therefore suitable for regular checks of the mechanical isocenter characteristics of the gantry and collimator rotation axis. When the isocenter path is reproducible and its extent is in the range of the needed geometrical accuracy, it should be taken into account in the planning process. This is especially true for stereotactic treatments and radiosurgery

  19. Measurements of isocenter path characteristics of the gantry rotation axis with a smartphone application

    Energy Technology Data Exchange (ETDEWEB)

    Schiefer, H., E-mail: johann.schiefer@kssg.ch; Peters, S.; Plasswilm, L. [Klinik für Radio-Onkologie, Kantonsspital St.Gallen, Rorschacherstrasse 107, St.Gallen CH-9007 (Switzerland); Ingulfsen, N.; Kluckert, J. [Kantonsschule am Burggraben St.Gallen, Burggraben 21, St.Gallen CH-9000 (Switzerland)

    2015-03-15

    Purpose: For stereotactic radiosurgery, the AAPM Report No. 54 [AAPM Task Group 42 (AAPM, 1995)] requires the overall stability of the isocenter (couch, gantry, and collimator) to be within a 1 mm radius. In reality, a rotating system has no rigid axis and thus no isocenter point which is fixed in space. As a consequence, the isocenter concept is reviewed here. It is the aim to develop a measurement method following the revised definitions. Methods: The mechanical isocenter is defined here by the point which rotates on the shortest path in the room coordinate system. The path is labeled as “isocenter path.” Its center of gravity is assumed to be the mechanical isocenter. Following this definition, an image-based and radiation-free measurement method was developed. Multiple marker pairs in a plane perpendicular to the assumed gantry rotation axis of a linear accelerator are imaged with a smartphone application from several rotation angles. Each marker pair represents an independent measuring system. The room coordinates of the isocenter path and the mechanical isocenter are calculated based on the marker coordinates. The presented measurement method is by this means strictly focused on the mechanical isocenter. Results: The measurement result is available virtually immediately following completion of measurement. When 12 independent measurement systems are evaluated, the standard deviations of the isocenter path points and mechanical isocenter coordinates are 0.02 and 0.002 mm, respectively. Conclusions: The measurement is highly accurate, time efficient, and simple to adapt. It is therefore suitable for regular checks of the mechanical isocenter characteristics of the gantry and collimator rotation axis. When the isocenter path is reproducible and its extent is in the range of the needed geometrical accuracy, it should be taken into account in the planning process. This is especially true for stereotactic treatments and radiosurgery.

  20. Mechanical impedance of the sitting human body in single-axis compared to multi-axis whole-body vibration exposure.

    Science.gov (United States)

    Holmlund, P; Lundström, R

    2001-01-01

    The study was aimed to investigate the mechanical impedance of the sitting human body and to compare data obtained in laboratory single-axis investigations with multi-axis data from in vehicle measurements. The experiments were performed in a laboratory for single-axis measurements. The multi-axis exposure was generated with an eight-seat minibus where the rear seats had been replaced with a rigid one. The subjects in the multi-axis experiment all participated in the single-axis experiments. There are quite a few investigations in the literature describing the human response to single-axis exposure. The response from the human body can be expected to be affected by multi-axis input in a different way than from a single-axis exposure. The present knowledge of the effect of multiple axis exposure is very limited. The measurements were performed using a specially designed force and accelerometer plate. This plate was placed between the subject and the hard seat. Outcome shows a clear difference between mechanical impedance for multi-axis exposure compared to single-axis. This is especially clear in the x-direction where the difference is very large. The conclusion is that it seems unlikely that single-axis mechanical impedance data can be directly transferred to a multi-axis environment. This is due to the force cross-talk between different directions.

  1. Variable substrate temperature deposition of CoFeB film on Ta for manipulating the perpendicular coercive forces

    Science.gov (United States)

    Lakshmanan, Saravanan; Rao, Subha Krishna; Muthuvel, Manivel Raja; Chandrasekaran, Gopalakrishnan; Therese, Helen Annal

    2017-08-01

    Magnetization of Ta/CoFeB/Ta trilayer films with thick layer of CoFeB deposited under different substrate temperatures (Ts) via ultra-high vacuum DC sputtering technique has been measured with the applied magnetic field parallel and perpendicular to the plane of the film respectively to study the perpendicular coercive forces of the film. The samples were further analyzed for its structural, topological, morphological, and electrical transport properties. The core chemical states for the elements present in the CoFeB thin film were analyzed by XPS studies. Magnetization studies reveal the existence of perpendicular coercive forces in CoFeB films deposited only at certain temperatures such as RT, 450 °C, 475 °C and 500 °C. CoFeB film deposited at 475 °C exhibited a maximum coercivity of 315 Oe and a very low saturation magnetization (Ms) of 169 emu/cc in perpendicular direction. This pronounced effect in perpendicular coercive forces observed for CoFeB475 could be attributed to the effect of temperature in enhancing the crystallization of the film at the Ta/CoFeB interfaces. However at temperatures higher than 475 °C the destruction of the Ta/CoFeB interface due to intermixing of Ta and CoFeB results in the disappearance of magnetic anisotropy.

  2. Highly tunable perpendicularly magnetized synthetic antiferromagnets for biotechnology applications

    OpenAIRE

    Vemulkar, T; Mansell, Rhodri; Petit, Dorothee Celine; Cowburn, Russell Paul; Lesniak, MS

    2015-01-01

    Magnetic micro and nanoparticles are increasingly used in biotechnological applications due to the ability to control their behavior through an externally applied field. We demonstrate the fabrication of particles made from ultrathin perpendicularly magnetized CoFeB/Pt layers with antiferromagnetic interlayer coupling. The particles are characterized by zero moment at remanence, low susceptibility at low fields, and a large saturated moment created by the stacking of the basic coupled bilayer...

  3. Antidot patterned single and bilayer thin films based on ferrimagnetic Tb-Co alloy with perpendicular magnetic anisotropy

    Science.gov (United States)

    Kulesh, N. A.; Vázquez, M.; Lepalovskij, V. N.; Vas'kovskiy, V. O.

    2018-02-01

    Hysteresis properties and magnetization reversal in TbCo(30 nm) and FeNi(10 nm)/TbCo(30 nm) films with nanoscale antidot lattices are investigated to test the effect of nanoholes on the perpendicular anisotropy in the TbCo layer and the induced exchange bias in the FeNi layer. The antidots are introduced by depositing the films on top of hexagonally ordered porous anodic alumina substrates with pore diameter and interpore distance fixed to 75 nm and 105 nm, respectively. The analysis of combined vibrating sample magnetometry, Kerr microscopy and magnetic force microscopy imaging measurements has allowed us to link macroscopic and local magnetization reversal processes. For magnetically hard TbCo films, we demonstrate the tunability of magnetic anisotropy and coercive field (i.e., it increases from 0.2 T for the continuous film to 0.5 T for the antidot film). For the antidot FeNi/TbCo film, magnetization of FeNi is confirmed to be in plane. Although an exchange bias has been locally detected in the FeNi layer, the integrated hysteresis loop has increased coercivity and zero shift along the field axis due to the significantly decreased magnetic anisotropy of TbCo layer.

  4. On the Turbulent Mixing in Horizontal Axis Wind Turbine Wakes

    NARCIS (Netherlands)

    Lignarolo, L.E.M.

    2016-01-01

    The wake flow of a horizontal axis wind turbine is characterised by lower wind speed and higher turbulence than the free-stream conditions. When clustered in large wind farms, wind turbines regularly operate inside the wake of one or more upstream machines. This is a major cause of energy production

  5. Environmental stressors and epigenetic control of the hypothalamic-pituitary-adrenal-axis (HPA-axis)

    OpenAIRE

    Lee, Richard; Sawa, Akira

    2014-01-01

    In this review, we provide a brief summary of several key studies that broaden our understanding of stress and its epigenetic control of the hypothalamic-pituitary-adrenal axis (HPA)-axis function and behavior. Clinical and animal studies suggest a link among exposure to stress, dysregulation of the HPA-axis, and susceptibility to neuropsychiatric illnesses. Recent studies have supported the notion that exposure to glucocorticoids and stress in various forms, duration, and intensity during di...

  6. Perpendicular eν mass from W decay

    International Nuclear Information System (INIS)

    Barger, V.; Martin, A.G.; Phillips, R.J.N.

    1983-01-01

    Properties of the perpendicular eν mass, defined in terms of transverse momenta p-vectorsub(T) by Msub(T)sup(2)(eν) = 2|p-vectorsub(eT)| |p-vectorsub(νT)| - 2p-vectorsub(eT).p-vectorsub(νT), that make it particularly well suited to W mass and width determinations are examined. An analytic expression for its distribution in W production and subsequent W → eν decay at p-barp colliders, accurate to order approximately equal to 1% is given. A maximum likelihood fit of this formula to the five UA1 events gives Msub(W) = 80.3 +- 3 6 GeV. (author)

  7. The GH/IGF-1 axis in ageing and longevity

    Science.gov (United States)

    List, Edward O.; Berryman, Darlene E.; Murrey, John W.

    2014-01-01

    Secretion of growth hormone (GH), and consequently that of insulin-like growth factor 1 (IGF-1), declines over time until only low levels can be detected in individuals aged ≥60 years. This phenomenon, which is known as the ‘somatopause’, has led to recombinant human GH being widely promoted and abused as an antiageing drug, despite lack of evidence of efficacy. By contrast, several mutations that decrease the tone of the GH/IGF-1 axis are associated with extended longevity in mice. In humans, corresponding or similar mutations have been identified, but whether these mutations alter longevity has yet to be established. The powerful effect of reduced GH activity on lifespan extension in mice has generated the hypothesis that pharmaceutically inhibiting, rather than increasing, GH action might delay ageing. Moreover, mice as well as humans with reduced activity of the GH/IGF-1 axis are protected from cancer and diabetes mellitus, two major ageing-related morbidities. Here, we review data on mouse strains with alterations in the GH/IGF-1 axis and their effects on lifespan. The outcome of corresponding or similar mutations in humans is described, as well as the potential mechanisms underlying increased longevity and the therapeutic benefits and risks of medical disruption of the GH/IGF-1 axis in humans. PMID:23591370

  8. Molecular frame photoelectron angular distribution for oxygen 1s photoemission from CO2 molecules

    International Nuclear Information System (INIS)

    Saito, N; Ueda, K; De Fanis, A

    2005-01-01

    We have measured photoelectron angular distributions in the molecular frame (MF-PADs) for O 1s photoemission from CO 2 , using photoelectron-O + -CO + coincidence momentum imaging. Results for the molecular axis at 0, 45 and 90 0 to the electric vector of the light are reported. The major features of the MF-PADs are fairly well reproduced by calculations employing a relaxed-core Hartree-Fock approach. Weak asymmetric features are seen through a plane perpendicular to the molecular axis and attributed to symmetry lowering by anti-symmetric stretching motion. (letter to the editor)

  9. HPA axis hyperactivity and attempted suicide in young adult mood disorder inpatients.

    Science.gov (United States)

    Jokinen, Jussi; Nordström, Peter

    2009-07-01

    Hyperactivity of the Hypothalamic-Pituitary-Adrenal (HPA) axis is a consistent finding in Major Depressive Disorder (MDD) and most prospective studies of HPA-axis function have found that non-suppressors in the dexamethasone suppression test (DST) are more likely to commit suicide during follow-up. The results of studies on HPA-axis function and attempted suicide are less consistent. Suicide attempts are more common among young people than the elderly, whereas suicide is more common among the elderly. The impact of age related changes in HPA-axis system activity in relation to suicidal behaviour across the lifecycle may be of importance. The aim of the present study was to investigate the DST results in 36 young adult (30 years or younger) inpatients with mood disorder, with (n=18) and without suicide attempt at the index episode. The DST non-suppressor rate was 25% among young mood disorder inpatients. DST non-suppression was associated with suicide attempt and post-dexamethasone serum cortisol at 11:00 p.m. was significantly higher in suicide attempters compared to non-attempters. The DST non-suppressor rate was 39% in young adult suicide attempters compared with 11% in non-attempters. The results add to previous evidence in support of the role of HPA axis hyperactivity and suicidal behaviour. The present findings motivate to include HPA axis measures in the assessment of depression in young adults.

  10. Effect of tearing modes on temperature and density profiles and on the perpendicular transport in the W VII-A stellarator

    International Nuclear Information System (INIS)

    Jaenicke, R.

    1988-01-01

    In the ohmically heated W VII-A stellarator, the behaviour of which is similar to that of a medium sized tokamak, the additional shearless external rotational transform t 0 (Δt 0 /t 0 0 perpendicular,e in a one-dimensional heat transport code. In this way, the measured temperature profiles can be reproduced quite well and the energy confinement time of discharges with tearing mode activity can be predicted quantitatively. The transport model is used to investigate the explicit dependence of κ perpendicular,e on the plasma current and to study the importance of plasma current driven instabilities for the energy confinement in the W VII-A stellarator as well as in tokamaks. (author). 19 refs, 14 figs

  11. Domain structures and temperature-dependent spin reorientation transitions in c-axis oriented Co-Cr thin films

    International Nuclear Information System (INIS)

    Kusinski, Greg J.; Krishnan, Kannan M.; Thomas, Gareth; Nelson, E. C.

    2000-01-01

    Highly c-axis oriented Co 95 Cr 5 films with perpendicular anisotropy were grown epitaxially on Si (111), using an Ag seed layer, by physical vapor deposition. Films were characterized by x-ray diffraction, transmission electron microscopy (TEM), selected area electron diffraction, and Lorentz microscopy in a TEM. The following epitaxial relationship was confirmed: (111) Si (parallel sign)(111) Ag (parallel sign)(0001) CoCr ;[2(bar sign)20] Si (parallel sign)[2(bar sign)20] Ag (parallel sign)[1(bar sign)100] CoCr . Magnetic domain structures of these films were observed as a function of thickness; t, in the range, 200 Aa c ≅300 Aa, the magnetization was found to be effectively in-plane of the film, and above t c a regular, stripe-like domain pattern with a significant, alternating in sign, perpendicular component was observed. The spin reorientation transitions of the stripe domains to the in-plane magnetization were studied dynamically by observing the domains as a function of temperature by in situ heating up to 350 degree sign C. The critical transition thickness, t c , which is a function of K u and magnetostatic energy, was found to increase with increasing temperature. The stripe-domain period, L observed at room temperature was found to increase gradually with thickness; L=90 nm at t=300 Aa, and L=110 nm at t=700 Aa. (c) 2000 American Institute of Physics

  12. Algebra of 2D periodic operators with local and perpendicular defects

    DEFF Research Database (Denmark)

    Kutsenko, Anton

    2016-01-01

    We show that 2D periodic operators with local and perpendicular defects form an algebra. We provide an algorithm for finding spectrum for such operators. While the continuous spectral components can be computed by simple algebraic operations on some matrix-valued functions and a few number...

  13. Tearing modes induced by perpendicular electron cyclotron resonance heating in the KSTAR tokamak

    International Nuclear Information System (INIS)

    Lee, H.H.; Lee, S.G.; Seol, J.; Aydemir, A.Y.; Bae, C.; Woo, M.H.; Kim, J.; Joung, M.; You, K.I.; Park, B.H.; Yoo, J.W.; Na, Y.S.; Kim, H.S.

    2014-01-01

    This paper reports on experimental evidence that shows perpendicular electron cyclotron resonance heating (ECRH) can trigger classical tearing modes when deposited near a rational flux surface. The complex evolution of an m = 2 island is followed during current ramp-up in KSTAR plasmas, from its initial onset as the rational surface enters the ECRH resonance layer to its eventual lock on the wall after the rational surface leaves the layer. Stability analysis coupled to a transport calculation of the current profile with ECRH shows that the perpendicular ECRH may play a significant role in triggering and destabilizing classical m = 2 tearing modes, in agreement with our experimental observation. (paper)

  14. Feasibilty of a Multi-bit Cell Perpendicular Magnetic Tunnel Junction Device

    Science.gov (United States)

    Kim, Chang Soo

    The ultimate objective of this research project was to explore the feasibility of making a multi-bit cell perpendicular magnetic tunnel junction (PMTJ) device to increase the storage density of spin-transfer-torque random access memory (STT-RAM). As a first step toward demonstrating a multi-bit cell device, this dissertation contributed a systematic and detailed study of developing a single cell PMTJ device using L10 FePt films. In the beginning of this research, 13 up-and-coming non-volatile memory (NVM) technologies were investigated and evaluated to see whether one of them might outperform NAND flash memories and even HDDs on a cost-per-TB basis in 2020. This evaluation showed that STT-RAM appears to potentially offer superior power efficiency, among other advantages. It is predicted that STTRAM's density could make it a promising candidate for replacing NAND flash memories and possibly HDDs if STTRAM could be improved to store multiple bits per cell. Ta/Mg0 under-layers were used first in order to develop (001) L1 0 ordering of FePt at a low temperature of below 400 °C. It was found that the tradeoff between surface roughness and (001) L10 ordering of FePt makes it difficult to achieve low surface roughness and good perpendicular magnetic properties simultaneously when Ta/Mg0 under-layers are used. It was, therefore, decided to investigate MgO/CrRu under-layers to simultaneously achieve smooth films with good ordering below 400°C. A well ordered 4 nm L10 FePt film with RMS surface roughness close to 0.4 nm, perpendicular coercivity of about 5 kOe, and perpendicular squareness near 1 was obtained at a deposition temperature of 390 °C on a thermally oxidized Si substrate when MgO/CrRu under-layers are used. A PMTJ device was developed by depositing a thin MgO tunnel barrier layer and a top L10 FePt film and then being postannealed at 450 °C for 30 minutes. It was found that the sputtering power needs to be minimized during the thin MgO tunnel barrier

  15. Does the GH/IGF-1 axis contribute to skeletal sexual dimorphism? Evidence from mouse studies.

    Science.gov (United States)

    Liu, Zhongbo; Mohan, Subburaman; Yakar, Shoshana

    2016-04-01

    The contribution of the gonadotropic axis to skeletal sexual dimorphism (SSD) was clarified in recent years. Studies with animal models of estrogen receptor (ER) or androgen receptor (AR) null mice, as well as mice with bone cell-specific ablation of ER or AR, revealed that both hormones play major roles in skeletal acquisition, and that estrogen regulates skeletal accrual in both sexes. The growth hormone (GH) and its downstream effector, the insulin-like growth factor-1 (IGF-1) are also major determinants of peak bone mass during puberty and young adulthood, and play important roles in maintaining bone integrity during aging. A few studies in both humans and animal models suggest that in addition to the differences in sex steroid actions on bone, sex-specific effects of GH and IGF-1 play essential roles in SSD. However, the contributions of the somatotropic (GH/IGF-1) axis to SSD are controversial and data is difficult to interpret. GH/IGF-1 are pleotropic hormones that act in an endocrine and autocrine/paracrine fashion on multiple tissues, affecting body composition as well as metabolism. Thus, understanding the contribution of the somatotropic axis to SSD requires the use of mouse models that will differentiate between these two modes of action. Elucidation of the relative contribution of GH/IGF-1 axis to SSD is significant because GH is approved for the treatment of normal children with short stature and children with congenital growth disorders. Thus, if the GH/IGF-1 axis determines SSD, treatment with GH may be tailored according to sex. In the following review, we give an overview of the roles of sex steroids in determining SSD and how they may interact with the GH/IGF-1 axis in bone. We summarize several mouse models with impaired somatotropic axis and speculate on the possible contribution of that axis to SSD. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Spin-torque oscillation in large size nano-magnet with perpendicular magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Linqiang, E-mail: LL6UK@virginia.edu [Department of Physics, University of Virginia, Charlottesville, VA 22904 (United States); Kabir, Mehdi [Department of Electrical & Computer Engineering, University of Virginia, Charlottesville, VA 22904 (United States); Dao, Nam; Kittiwatanakul, Salinporn [Department of Materials Science & Engineering, University of Virginia, Charlottesville, VA 22904 (United States); Cyberey, Michael [Department of Electrical Engineering, University of Virginia, Charlottesville, VA 22904 (United States); Wolf, Stuart A. [Department of Physics, University of Virginia, Charlottesville, VA 22904 (United States); Department of Materials Science & Engineering, University of Virginia, Charlottesville, VA 22904 (United States); Institute of Defense Analyses, Alexandria, VA 22311 (United States); Stan, Mircea [Department of Electrical & Computer Engineering, University of Virginia, Charlottesville, VA 22904 (United States); Lu, Jiwei [Department of Materials Science & Engineering, University of Virginia, Charlottesville, VA 22904 (United States)

    2017-06-15

    Highlights: • 500 nm size nano-pillar device was fabricated by photolithography techniques. • A magnetic hybrid structure was achieved with perpendicular magnetic fields. • Spin torque switching and oscillation was demonstrated in the large sized device. • Micromagnetic simulations accurately reproduced the experimental results. • Simulations demonstrated the synchronization of magnetic inhomogeneities. - Abstract: DC current induced magnetization reversal and magnetization oscillation was observed in 500 nm large size Co{sub 90}Fe{sub 10}/Cu/Ni{sub 80}Fe{sub 20} pillars. A perpendicular external field enhanced the coercive field separation between the reference layer (Co{sub 90}Fe{sub 10}) and free layer (Ni{sub 80}Fe{sub 20}) in the pseudo spin valve, allowing a large window of external magnetic field for exploring the free-layer reversal. A magnetic hybrid structure was achieved for the study of spin torque oscillation by applying a perpendicular field >3 kOe. The magnetization precession was manifested in terms of the multiple peaks on the differential resistance curves. Depending on the bias current and applied field, the regions of magnetic switching and magnetization precession on a dynamical stability diagram has been discussed in details. Micromagnetic simulations are shown to be in good agreement with experimental results and provide insight for synchronization of inhomogeneities in large sized device. The ability to manipulate spin-dynamics on large size devices could be proved useful for increasing the output power of the spin-transfer nano-oscillators (STNOs).

  17. Hair cortisol as a marker of hypothalamic-pituitary-adrenal Axis activity in female patients with major depressive disorder.

    Science.gov (United States)

    Pochigaeva, Ksenia; Druzhkova, Tatiana; Yakovlev, Alexander; Onufriev, Mikhail; Grishkina, Maria; Chepelev, Aleksey; Guekht, Alla; Gulyaeva, Natalia

    2017-04-01

    Hair cortisol is regarded as a promising marker of hypothalamic-pituitary-adrenal axis (HPAA) activity alterations due to stress, somatic and mental health conditions. Hair cortisol was previously reported to be elevated in patients with depression, however the data related to remission and recurrent depressive episodes are different. In this study, levels of hair cortisol were assessed in female patients with major depressive disorder (MDD) and the validity of hair cortisol as a marker of HPAA activity in this condition was evaluated. Hair cortisol was measured in 1 cm hair segments of 21 female patients with MDD and 22 female age-matched controls using enzyme-immunoassay analysis. Concurrently, serum cortisol was assessed and psychological status was evaluated using 17-item Hamilton Depression Rating Scale (HAMD-17), Beck Depression Inventory (BDI) and the Spielberger state trait anxiety inventory (STAI). The levels of hair cortisol were significantly lower in the MDD group, while serum cortisol levels were significantly higher in patients, as compared with controls. A significant negative correlation was found between HAMD-17 scores and hair cortisol. Decreased hair cortisol found in female patients with MDD as compared to controls suggests downregulation of HPAA activity during the preceding month. Further studies are needed to investigate the profiles of hair cortisol at different stages of depressive disorder to establish this parameter as a handy clinical tool.

  18. Crescent shaped Fabry-Perot fiber cavity for ultra-sensitive strain measurement

    Science.gov (United States)

    Liu, Ye; Wang, D. N.; Chen, W. P.

    2016-12-01

    Optical Fabry-Perot interferometer sensors based on inner air-cavity is featured with compact size, good robustness and high strain sensitivity, especially when an ultra-thin air-cavity is adopted. The typical shape of Fabry-Perot inner air-cavity with reflection mode of operation is elliptic, with minor axis along with and major axis perpendicular to the fiber length. The first reflection surface is diverging whereas the second one is converging. To increase the visibility of the output interference pattern, the length of major axis should be large for a given cavity length. However, the largest value of the major axis is limited by the optical fiber diameter. If the major axis length reaches the fiber diameter, the robustness of the Fabry-Perot cavity device would be decreased. Here we demonstrate an ultra-thin crescent shaped Fabry-Perot cavity for strain sensing with ultra-high sensitivity and low temperature cross-sensitivity. The crescent-shape cavity consists of two converging reflection surfaces, which provide the advantages of enhanced strain sensitivity when compared with elliptic or D-shaped FP cavity. The device is fabricated by fusion splicing an etched multimode fiber with a single mode fiber, and hence is simple in structure and economic in cost.

  19. Recording performances in perpendicular magnetic patterned media

    International Nuclear Information System (INIS)

    Asbahi, M; Moritz, J; Dieny, B; Gourgon, C; Perret, C; Van de Veerdonk, R J M

    2010-01-01

    We report on the recording performances and signal-to-noise ratio (SNR) analyses of perpendicular magnetic bit-patterned media. Two different types of magnetic samples are investigated. They differ by the way that they were patterned (nano-imprint versus e-beam lithography) as well as their magnetic properties (Co/Pt multilayers and CoCrPt alloy are the recording layers).Using a contact read/write quasi-static tester, we were able to characterize the write windows, the bit error rates and measure the SNR. The influence of magnetic properties and media microstructure on the writing processes is studied. We show also that the lithographical method used to replicate the media induces more or less noise due to structural distributions.

  20. Glucocorticoids and relapse of major depression (dexamethasone/corticotropin-releasing hormone test in relation to relapse of major depression)

    NARCIS (Netherlands)

    Appelhof, Bente C.; Huyser, Jochanan; Verweij, Mijke; Brouwer, Jantien P.; van Dyck, Richard; Fliers, Eric; Hoogendijk, Witte J. G.; Tijssen, Jan G. P.; Wiersinga, Wilmar M.; Schene, Aart H.

    2006-01-01

    BACKGROUND: Knowledge of pathogenic mechanisms and predictors of relapse in major depressive disorder is still limited. Hypothalamic-pituitary-adrenocortical (HPA) axis dysregulation is thought to be related to the development and course of depression. METHODS: We investigated whether

  1. Dimensional behavior of the anisotropy in the mixed state of a-axis oriented EuBa{sub 2}Cu{sub 3}O{sub 7}/PrBa{sub 2}Cu{sub 3}O{sub 7} and EuBa{sub 2}Cu{sub 3}O{sub 7}/SrTiO{sub 3} multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, E.M.; Gonzalez, J.M. [Consejo Superior de Investigaciones Cientificas, Madrid (Spain). Inst. de Ciencia de Materiales; Gomez, A.M. [Dept. de Fisica de Materiales, Univ. Nacional de Educacion a Distancia, Madrid (Spain); Vicent, J.L. [Dept. de Fisica de Materiales, Univ. Complutense, Madrid (Spain)

    1998-01-01

    Thin films and superconducting/insulating multilayers of the 123-high temperature superconductor (HTS) family have been grown by a sputtering technique. The samples are grown with the so-called a-axis orientation (CuO{sub 2} planes perpendicular to the substrate). The angular dependence of the onset of dissipation (resistivity) has been measured with applied magnetic fields up to 90 kOe. In the a-axis multilayers the artificially induced anisotropy oververcomes the intrinsic anisotropy in a broad angular interval, and the insulating layers break down the dimensional scaling laws above some critical angle ({theta}{sub c}). (orig.) 8 refs.

  2. What can we learn from p perpendicular spectra in heavy-ion collisions at the AGS?

    International Nuclear Information System (INIS)

    Cole, B.A.

    1994-01-01

    Inclusive and semi-inclusive cross-sections for production of pions, kaons, and protons in Si+Al, Si+Cu, and Si+Au collisions, measured at the nucleon-nucleon center-of-mass rapidity are presented. The functional forms of the spectra are discussed. The centrality dependence of the inverse m perpendicular slopes is shown. Deviations in the spectra from pure exponential-m perpendicular distributions are discussed. The effects of resonance decays on the shape of the pion spectra are studied using previously measured p-p data, Si+Al data from E802, and the ARC model

  3. Anomalous Hall effect assisted by interfacial chemical reaction in perpendicular Co/Pt multilayers

    Science.gov (United States)

    Liu, Qian; Jiang, Shaolong; Teng, Jiao

    2018-05-01

    To uncover the underlying mechanism of Mg effect on the improved anomalous Hall effect (AHE) of perpendicular [Pt/Co]3/Mg/HfO2 multilayers, the X-ray photoelectron spectroscopy analysis has been carried out. It is found that Mg interlayer at the Co/HfO2 interface could prevent the Co oxidation to some extent via interfacial chemical reaction. As a result, A large anomalous Hall resistivity (ρAH) is obtained in perpendicular [Pt/Co]3/Mg/HfO2 multilayers, with a maximum ρAH of 3.02 μΩ cm, which is 59% larger than that in Co/Pt multilayers without Mg insertion. This effective modification of the AHE based on interfacial chemical reaction provides a promising pathway for spintronic applications.

  4. Magnetic stripes and holes: Complex domain patterns in perforated films with weak perpendicular anisotropy

    Directory of Open Access Journals (Sweden)

    F. Valdés-Bango

    2017-05-01

    Full Text Available Hexagonal antidot arrays have been patterned on weak perpendicular magnetic anisotropy NdCo films by e-beam lithography and lift off. Domain structure has been characterized by Magnetic Force Microscopy at remanence. On a local length scale, of the order of stripe pattern period, domain configuration is controlled by edge effects within the stripe pattern: stripe domains meet the hole boundary at either perpendicular or parallel orientation. On a longer length scale, in-plane magnetostatic effects dominate the system: clear superdomains are observed in the patterned film with average in-plane magnetization along the easy directions of the antidot array, correlated over several antidot array cells.

  5. Magnetic stripes and holes: Complex domain patterns in perforated films with weak perpendicular anisotropy

    Science.gov (United States)

    Valdés-Bango, F.; Vélez, M.; Alvarez-Prado, L. M.; Alameda, J. M.; Martín, J. I.

    2017-05-01

    Hexagonal antidot arrays have been patterned on weak perpendicular magnetic anisotropy NdCo films by e-beam lithography and lift off. Domain structure has been characterized by Magnetic Force Microscopy at remanence. On a local length scale, of the order of stripe pattern period, domain configuration is controlled by edge effects within the stripe pattern: stripe domains meet the hole boundary at either perpendicular or parallel orientation. On a longer length scale, in-plane magnetostatic effects dominate the system: clear superdomains are observed in the patterned film with average in-plane magnetization along the easy directions of the antidot array, correlated over several antidot array cells.

  6. Comparison of Classical Linear Regression and Orthogonal Regression According to the Sum of Squares Perpendicular Distances

    OpenAIRE

    KELEŞ, Taliha; ALTUN, Murat

    2016-01-01

    Regression analysis is a statistical technique for investigating and modeling the relationship between variables. The purpose of this study was the trivial presentation of the equation for orthogonal regression (OR) and the comparison of classical linear regression (CLR) and OR techniques with respect to the sum of squared perpendicular distances. For that purpose, the analyses were shown by an example. It was found that the sum of squared perpendicular distances of OR is smaller. Thus, it wa...

  7. Variable substrate temperature deposition of CoFeB film on Ta for manipulating the perpendicular coercive forces

    Energy Technology Data Exchange (ETDEWEB)

    Lakshmanan, Saravanan; Rao, Subha Krishna [Nanotechnology Research Centre, SRM University, Kattankulathur, Chennai 603203 (India); Muthuvel, Manivel Raja [Defence Metallurgical Research Laboratory (DMRL), Hyderabad 500058 (India); Chandrasekaran, Gopalakrishnan [Nanotechnology Research Centre, SRM University, Kattankulathur, Chennai 603203 (India); Therese, Helen Annal, E-mail: helen.a@ktr.srmuniv.ac.in [Nanotechnology Research Centre, SRM University, Kattankulathur, Chennai 603203 (India)

    2017-08-01

    Highlights: • Ta/CoFeB(50 nm)/Ta thin films were deposited at various substrate temperatures (T{sub s}). • CoFeB films deposited at T{sub s} such as RT, 450 °C, 475 °C and 500 °C exhibited perpendicular coercivity. • CoFeB deposited at 475 °C displayed a higher coercivity of 315 Oe and a low M{sub s} of 169 emu/cc. • The enhanced crystallization of CoFeB at the Ta/CoFeB interface results in higher H{sub c} (⟂). - Abstract: Magnetization of Ta/CoFeB/Ta trilayer films with thick layer of CoFeB deposited under different substrate temperatures (T{sub s}) via ultra-high vacuum DC sputtering technique has been measured with the applied magnetic field parallel and perpendicular to the plane of the film respectively to study the perpendicular coercive forces of the film. The samples were further analyzed for its structural, topological, morphological, and electrical transport properties. The core chemical states for the elements present in the CoFeB thin film were analyzed by XPS studies. Magnetization studies reveal the existence of perpendicular coercive forces in CoFeB films deposited only at certain temperatures such as RT, 450 °C, 475 °C and 500 °C. CoFeB film deposited at 475 °C exhibited a maximum coercivity of 315 Oe and a very low saturation magnetization (M{sub s}) of 169 emu/cc in perpendicular direction. This pronounced effect in perpendicular coercive forces observed for CoFeB475 could be attributed to the effect of temperature in enhancing the crystallization of the film at the Ta/CoFeB interfaces. However at temperatures higher than 475 °C the destruction of the Ta/CoFeB interface due to intermixing of Ta and CoFeB results in the disappearance of magnetic anisotropy.

  8. In Search of HPA Axis Dysregulation in Child and Adolescent Depression

    Science.gov (United States)

    Guerry, John D.; Hastings, Paul D.

    2011-01-01

    Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis in adults with major depressive disorder is among the most consistent and robust biological findings in psychiatry. Given the importance of the adolescent transition to the development and recurrence of depressive phenomena over the lifespan, it is important to have an integrative…

  9. Associations in the Course of Personality Disorders and Axis I Disorders Over Time

    Science.gov (United States)

    Shea, M. Tracie; Yen, Shirley; Pagano, Maria E.; Morey, Leslie C.; McGlashan, Thomas H.; Grilo, Carlos M.; Sanislow, Charles A.; Stout, Robert L.; Skodol, Andrew E.; Gunderson, John G.; Bender, Donna S.; Zanarini, Mary C.

    2012-01-01

    In this study, the authors examined time-varying associations between schizotypal (STPD), borderline (BPD), avoidant (AVPD), or obsessive–compulsive (OCPD) personality disorders and co-occurring Axis I disorders in 544 adult participants from the Collaborative Longitudinal Personality Disorders Study. The authors tested predictions of specific longitudinal associations derived from a model of crosscutting psychobiological dimensions (L. J. Siever & K. L. Davis, 1991) with participants with the relevant Axis I disorders. The authors assessed participants at baseline and at 6-, 12-, and 24-month follow-up evaluations. BPD showed significant longitudinal associations with major depressive disorder and posttraumatic stress disorder. AVPD was significantly associated with anxiety disorders (specifically social phobia and obsessive–compulsive disorder). Two of the four personality disorders under examination (STPD and OCPD) showed little or no association with Axis I disorders. PMID:15535783

  10. Helical magnetic axis configuration combined with l = 1 and weak l = -1 torsatron fields

    International Nuclear Information System (INIS)

    Kikuchi, Hitoshi; Saito, Katsunori; Gesso, Hirokazu; Shiina, Shoichi

    1989-01-01

    The superposition of a relatively weak l = -1 torsatron field on a main l = 1 torsatron field leads to the improvement of the confinement properties due to the formation of a local magnetic well, which results from the local curvature of the helical magnetic axis with a larger excursion in the major radius direction. This l±1 helical magnetic axis system has a comparatively simple, compact coil structure. Here the vacuum configuration properties of l = ±1 system are described. (author)

  11. Determination of Screw and Nail Withdrawal Strengths in Parallel and Perpendicular to Grain of some Hardwoods of Iran

    Directory of Open Access Journals (Sweden)

    Sadegh Maleki

    2013-06-01

    Full Text Available In this study, screw and nail withdrawal strengths parallel and perpendicular longitudinal to grain of some hardwoods; oak (Quercus castaneifolia, hornbeam (Carpinus betulus, beech (Fagus orientalis, Sycamore (Platanus oriantalis and poplar (Populus deltoids were investigated. The tests were conducted following ASTM D 1761 with specimen dimension of 15×5×5(T×R×L. Three kinds of screws namely sheet metal screw, wood screw and coarse drywall screw with diameter of 4 and 5 mm were used. Three different nails with nominal diameter of 2.5, 3.25 and 3.75 mm were also used. The highest screw withdrawal strengths parallel and perpendicular to grain were related to hornbeam, beech, oak, Sycamore and poplar respectively. Furthermore, the highest nail withdrawal strengths parallel and perpendicular to grain were related to hornbeam, oak, beech, Sycamore and poplar respectively for nails with 3.75 mm diameter. Higher density and shear strength of hornbeam compared to the other species accounts for its high screw and nail withdrawal strengths parallel and perpendicular to grain.

  12. DO OBLIQUE ALFVÉN/ION-CYCLOTRON OR FAST-MODE/WHISTLER WAVES DOMINATE THE DISSIPATION OF SOLAR WIND TURBULENCE NEAR THE PROTON INERTIAL LENGTH?

    International Nuclear Information System (INIS)

    He Jiansen; Tu Chuanyi; Marsch, Eckart; Yao Shuo

    2012-01-01

    To determine the wave modes prevailing in solar wind turbulence at kinetic scales, we study the magnetic polarization of small-scale fluctuations in the plane perpendicular to the data sampling direction (namely, the solar wind flow direction, V SW ) and analyze its orientation with respect to the local background magnetic field B 0,local . As an example, we take only measurements made in an outward magnetic sector. When B 0,local is quasi-perpendicular to V SW , we find that the small-scale magnetic-field fluctuations, which have periods from about 1 to 3 s and are extracted from a wavelet decomposition of the original time series, show a polarization ellipse with right-handed orientation. This is consistent with a positive reduced magnetic helicity, as previously reported. Moreover, for the first time we find that the major axis of the ellipse is perpendicular to B 0,local , a property that is characteristic of an oblique Alfvén wave rather than oblique whistler wave. For an oblique whistler wave, the major axis of the magnetic ellipse is expected to be aligned with B 0,local , thus indicating significant magnetic compressibility, and the polarization turns from right to left handedness as the wave propagation angle (θ kB ) increases toward 90°. Therefore, we conclude that the observation of a right-handed polarization ellipse with orientation perpendicular to B 0,local seems to indicate that oblique Alfvén/ion-cyclotron waves rather than oblique fast-mode/whistler waves dominate in the 'dissipation' range near the break of solar wind turbulence spectra occurring around the proton inertial length.

  13. Numerical Test of Analytical Theories for Perpendicular Diffusion in Small Kubo Number Turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Heusen, M.; Shalchi, A., E-mail: husseinm@myumanitoba.ca, E-mail: andreasm4@yahoo.com [Department of Physics and Astronomy, University of Manitoba, Winnipeg, MB R3T 2N2 (Canada)

    2017-04-20

    In the literature, one can find various analytical theories for perpendicular diffusion of energetic particles interacting with magnetic turbulence. Besides quasi-linear theory, there are different versions of the nonlinear guiding center (NLGC) theory and the unified nonlinear transport (UNLT) theory. For turbulence with high Kubo numbers, such as two-dimensional turbulence or noisy reduced magnetohydrodynamic turbulence, the aforementioned nonlinear theories provide similar results. For slab and small Kubo number turbulence, however, this is not the case. In the current paper, we compare different linear and nonlinear theories with each other and test-particle simulations for a noisy slab model corresponding to small Kubo number turbulence. We show that UNLT theory agrees very well with all performed test-particle simulations. In the limit of long parallel mean free paths, the perpendicular mean free path approaches asymptotically the quasi-linear limit as predicted by the UNLT theory. For short parallel mean free paths we find a Rechester and Rosenbluth type of scaling as predicted by UNLT theory as well. The original NLGC theory disagrees with all performed simulations regardless what the parallel mean free path is. The random ballistic interpretation of the NLGC theory agrees much better with the simulations, but compared to UNLT theory the agreement is inferior. We conclude that for this type of small Kubo number turbulence, only the latter theory allows for an accurate description of perpendicular diffusion.

  14. Numerical Test of Analytical Theories for Perpendicular Diffusion in Small Kubo Number Turbulence

    International Nuclear Information System (INIS)

    Heusen, M.; Shalchi, A.

    2017-01-01

    In the literature, one can find various analytical theories for perpendicular diffusion of energetic particles interacting with magnetic turbulence. Besides quasi-linear theory, there are different versions of the nonlinear guiding center (NLGC) theory and the unified nonlinear transport (UNLT) theory. For turbulence with high Kubo numbers, such as two-dimensional turbulence or noisy reduced magnetohydrodynamic turbulence, the aforementioned nonlinear theories provide similar results. For slab and small Kubo number turbulence, however, this is not the case. In the current paper, we compare different linear and nonlinear theories with each other and test-particle simulations for a noisy slab model corresponding to small Kubo number turbulence. We show that UNLT theory agrees very well with all performed test-particle simulations. In the limit of long parallel mean free paths, the perpendicular mean free path approaches asymptotically the quasi-linear limit as predicted by the UNLT theory. For short parallel mean free paths we find a Rechester and Rosenbluth type of scaling as predicted by UNLT theory as well. The original NLGC theory disagrees with all performed simulations regardless what the parallel mean free path is. The random ballistic interpretation of the NLGC theory agrees much better with the simulations, but compared to UNLT theory the agreement is inferior. We conclude that for this type of small Kubo number turbulence, only the latter theory allows for an accurate description of perpendicular diffusion.

  15. Determination of the number of Vertical Axis Wind Turbine blades based on power spectrum

    Directory of Open Access Journals (Sweden)

    Fedak Waldemar

    2017-01-01

    Full Text Available Technology of wind exploitation has been applied widely all over the world and has already reached the level in which manufacturers want to maximize the yield with the minimum investment outlays. The main objective of this paper is the determination of the optimal number of blades in the Cup-Bladed Vertical Axis Wind Turbine. Optimizing the size of the Vertical Axis Wind Turbine allows the reduction of costs. The maximum power of the rotor is selected as the performance target. The optimum number of Vertical Axis Wind Turbine blades evaluation is based on analysis of a single blade simulation and its superposition for the whole rotor. The simulation of working blade was done in MatLab environment. Power spectrum graphs were prepared and compared throughout superposition of individual blades in the Vertical Axis Wind Turbine rotor. The major result of this research is the Vertical Axis Wind Turbine power characteristic. On the basis of the analysis of the power spectra, optimum number of the blades was specified for the analysed rotor. Power spectrum analysis of wind turbine enabled the specification of the optimal number of blades, and can be used regarding investment outlays and power output of the Vertical Axis Wind Turbine.

  16. Determination of the number of Vertical Axis Wind Turbine blades based on power spectrum

    Science.gov (United States)

    Fedak, Waldemar; Anweiler, Stanisław; Gancarski, Wojciech; Ulbrich, Roman

    2017-10-01

    Technology of wind exploitation has been applied widely all over the world and has already reached the level in which manufacturers want to maximize the yield with the minimum investment outlays. The main objective of this paper is the determination of the optimal number of blades in the Cup-Bladed Vertical Axis Wind Turbine. Optimizing the size of the Vertical Axis Wind Turbine allows the reduction of costs. The maximum power of the rotor is selected as the performance target. The optimum number of Vertical Axis Wind Turbine blades evaluation is based on analysis of a single blade simulation and its superposition for the whole rotor. The simulation of working blade was done in MatLab environment. Power spectrum graphs were prepared and compared throughout superposition of individual blades in the Vertical Axis Wind Turbine rotor. The major result of this research is the Vertical Axis Wind Turbine power characteristic. On the basis of the analysis of the power spectra, optimum number of the blades was specified for the analysed rotor. Power spectrum analysis of wind turbine enabled the specification of the optimal number of blades, and can be used regarding investment outlays and power output of the Vertical Axis Wind Turbine.

  17. Monte-Carlo calculation of perpendicular neutral-beam injection in helical systems

    International Nuclear Information System (INIS)

    Hanatani, K.; Wakatani, M.; Uo, K.

    1981-01-01

    The effect of a helical field ripple on the slowing-down process of the fast ions created by neutral injection is investigated numerically. For this purpose, the guiding-centre orbits are followed in a model magnetic field without plasma current, on the assumption that the slowing-down process is to be classical. Optimum injection angles in two types of helical magnetic traps are compared. One is the Heliotron-E configuration with a large rotational transform and deep helical ripple; the other one is the conventional stellarator field with a small rotational transform and shallow helical ripple. In contrast to the stellarator, the heating efficiency as calculated for Heliotron-E does not decrease monotonically when the injection angle is perpendicular to the toroidal direction; a heating efficiency of above 70% was obtained for perpendicular injection into a high-density plasma with negligible charge-exchange loss. The difference in heating efficiency versus injection angle between heliotron and conventional stellarator fields is explained by a difference in drift motion of the helically trapped fast ions. (author)

  18. Induced superconductivity in Nb/InAs-hybrid structures in parallel and perpendicular magnetic fields

    International Nuclear Information System (INIS)

    Rohlfing, Franziska

    2007-07-01

    The thesis in hand investigates experimentally Josephson contacts based on Nb/InAs-hybrid structures. The experiments discussed here were done on samples of different width of the Josephson contacts (between 500 nm and 2000 nm). They were realized by means of different methods of the semiconductor technology. The length of the Josephson contacts was about 600 nm and, as superconducting material, niobium was used. Both critical current and characteristics in the resistive regime (excess-current and multiple Andreev reflection) are studied as a function of temperature and external magnetic fields. Measurements in perpendicular and parallel magnetic fields with respect to the plain of the two-dimensional electron gas, are presented. The Andreev reflection amplitude determining the supercurrent is calculated by means of the Greens functions of the two-dimensional electron gas beneath the superconductors which is modified by the proximity effect. From the fit to the data with this model, the transparency of the boundary between the superconductor and the two-dimensional electron gas can be estimated to be about 0.1. The transparency of the point contacts in the two-dimensional electrons gas can be determined independently from the Josephson junction width dependence of the normal resistance (T=10 K). This transparency amounts to about 0.8 in the examined samples. The measurements of the critical current in a magnetic field perpendicular to the two-dimensional electron gas show a Fraunhofer pattern. In order to study the transition from perpendicular orientation into parallel orientation, measurements of the critical current as a function of the magnetic field were done for different angles. In the resistive regime, the excess current measurements in the magnetic field show a very interesting behaviour: In parallel magnetic fields, the excess current becomes zero at about 2.5 T. In perpendicular magnetic field however, the excess current is strongly suppressed below 30 m

  19. 2D biological representations with reduced speckle obtained from two perpendicular ultrasonic arrays.

    Science.gov (United States)

    Rodriguez-Hernandez, Miguel A; Gomez-Sacristan, Angel; Sempere-Payá, Víctor M

    2016-04-29

    Ultrasound diagnosis is a widely used medical tool. Among the various ultrasound techniques, ultrasonic imaging is particularly relevant. This paper presents an improvement to a two-dimensional (2D) ultrasonic system using measurements taken from perpendicular planes, where digital signal processing techniques are used to combine one-dimensional (1D) A-scans were acquired by individual transducers in arrays located in perpendicular planes. An algorithm used to combine measurements is improved based on the wavelet transform, which includes a denoising step during the 2D representation generation process. The inclusion of this new denoising stage generates higher quality 2D representations with a reduced level of speckling. The paper includes different 2D representations obtained from noisy A-scans and compares the improvements obtained by including the denoising stage.

  20. Aeroelastically coupled blades for vertical axis wind turbines

    Science.gov (United States)

    Paquette, Joshua; Barone, Matthew F.

    2016-02-23

    Various technologies described herein pertain to a vertical axis wind turbine blade configured to rotate about a rotation axis. The vertical axis wind turbine blade includes at least an attachment segment, a rear swept segment, and optionally, a forward swept segment. The attachment segment is contiguous with the forward swept segment, and the forward swept segment is contiguous with the rear swept segment. The attachment segment includes a first portion of a centroid axis, the forward swept segment includes a second portion of the centroid axis, and the rear swept segment includes a third portion of the centroid axis. The second portion of the centroid axis is angularly displaced ahead of the first portion of the centroid axis and the third portion of the centroid axis is angularly displaced behind the first portion of the centroid axis in the direction of rotation about the rotation axis.

  1. Magnetic properties of soft layer/FePt-MgO exchange coupled composite Perpendicular recording media

    Institute of Scientific and Technical Information of China (English)

    Yin Jin-Hua; Takao Suzuki; Pan Li-Qing

    2008-01-01

    The magnetic properties of exchange coupled composite(ECC)media that are composed of perpendicular magnetic recording media FePt-MgO and two kinds of soft layers have been studied by using an x-ray diffractometer,a polar Kerr magneto-optical system(PMOKE)and a vibrating sample magnetometer(VSM).The results show that ECC media can reduce the coercivities of perpendicular magnetic recording media FePt-MgO.The ECC media with granular-type soft layers have weaker exchange couplings between magnetic grains and the magnetization process,for ECC media of this kind mainly follow the Stoner-Wohlfarth model.

  2. Micropore extrusion-induced alignment transition from perpendicular to parallel of cylindrical domains in block copolymers.

    Science.gov (United States)

    Qu, Ting; Zhao, Yongbin; Li, Zongbo; Wang, Pingping; Cao, Shubo; Xu, Yawei; Li, Yayuan; Chen, Aihua

    2016-02-14

    The orientation transition from perpendicular to parallel alignment of PEO cylindrical domains of PEO-b-PMA(Az) films has been demonstrated by extruding the block copolymer (BCP) solutions through a micropore of a plastic gastight syringe. The parallelized orientation of PEO domains induced by this micropore extrusion can be recovered to perpendicular alignment via ultrasonication of the extruded BCP solutions and subsequent annealing. A plausible mechanism is proposed in this study. The BCP films can be used as templates to prepare nanowire arrays with controlled layers, which has enormous potential application in the field of integrated circuits.

  3. Flux-gate magnetometer spin axis offset calibration using the electron drift instrument

    International Nuclear Information System (INIS)

    Plaschke, Ferdinand; Nakamura, Rumi; Baumjohann, Wolfgang; Steller, Manfred; Magnes, Werner; Leinweber, Hannes K; Chutter, Mark; Vaith, Hans

    2014-01-01

    Spin-stabilization of spacecraft immensely supports the in-flight calibration of on-board flux-gate magnetometers (FGMs). From 12 calibration parameters in total, 8 can be easily obtained by spectral analysis. From the remaining 4, the spin axis offset is known to be particularly variable. It is usually determined by analysis of Alfvénic fluctuations that are embedded in the solar wind. In the absence of solar wind observations, the spin axis offset may be obtained by comparison of FGM and electron drift instrument (EDI) measurements. The aim of our study is to develop methods that are readily usable for routine FGM spin axis offset calibration with EDI. This paper represents a major step forward in this direction. We improve an existing method to determine FGM spin axis offsets from EDI time-of-flight measurements by providing it with a comprehensive error analysis. In addition, we introduce a new, complementary method that uses EDI beam direction data instead of time-of-flight data. Using Cluster data, we show that both methods yield similarly accurate results, which are comparable yet more stable than those from a commonly used solar wind-based method. (paper)

  4. Competing effect of spin-orbit torque terms on perpendicular magnetization switching in structures with multiple inversion asymmetries

    OpenAIRE

    Yu, Guoqiang; Akyol, Mustafa; Upadhyaya, Pramey; Li, Xiang; He, Congli; Fan, Yabin; Montazeri, Mohammad; Alzate, Juan G.; Lang, Murong; Wong, Kin L.; Khalili Amiri, Pedram; Wang, Kang L.

    2016-01-01

    Current-induced spin-orbit torques (SOTs) in structurally asymmetric multilayers have been used to efficiently manipulate magnetization. In a structure with vertical symmetry breaking, a damping-like SOT can deterministically switch a perpendicular magnet, provided an in-plane magnetic field is applied. Recently, it has been further demonstrated that the in-plane magnetic field can be eliminated by introducing a new type of perpendicular field-like SOT via incorporating a lateral structural a...

  5. Perpendicular magnetic anisotropy of amorphous ferromagnetic CoSiB/[Pt,Au] multilayer

    International Nuclear Information System (INIS)

    Jeong, S.; Yim, H. I.

    2012-01-01

    Perpendicular magnetic anisotropy is being widely studied as a possible candidate for a high density spin-transfer torque magnetic random access memory. The key issues of a high-density spin-transfer torque magnetic random access memory are decreasing the switching current and the high thermal stability. In order to solve these problems, two approaches are suggested: One is the development a new amorphous ferromagnetic material as a pinned layer for a multilayer with a low saturated magnetization (M s ) value because of the interface roughness between the two layers. The other is a search for the most suitable materials with high perpendicular magnetic anisotropy in order to have high thermal stability. In this work, we present an amorphous ferromagnetic Co 75 Si 15 B 10 material and compare the magnetic properties of a [CoSiB (0.3, 0.4, 0.5 nm)/Pt (1.4 nm)] 5 multilayer and new combinations [CoSiB (0.3, 0.4, 0.5 nm)/Au (1.5 nm)] 5 .

  6. Theoretical tool movement required to diamond turn an off-axis paraboloid on axis

    International Nuclear Information System (INIS)

    Thompson, D.C.

    1976-01-01

    Current techniques for manufacturing off-axis paraboloids are both expensive and insufficiently accurate. An alternative method, turning the workpiece about its axis on a diamond-turning machine, is presented, and the equations describing the necessary tool movement are derived. A discussion of a particular case suggests that the proposed technique is feasible

  7. Current perpendicular to plane giant magnetoresistance and tunneling magnetoresistance treated with unified model

    NARCIS (Netherlands)

    Jonkers, PAE

    2002-01-01

    The conceptual similarity between current perpendicular to plane giant magnetoresistance (CPP-GMR) and tunneling magnetoresistance (TMR) is exploited by utilizing a unified single-particle model accounting for both types of magnetoresistance. By defining structures composed of ferromagnetic,

  8. Finite-element modeling and micromagnetic modeling of perpendicular writers

    Science.gov (United States)

    Heinonen, Olle; Bozeman, Steven P.

    2006-04-01

    We compare finite-element modeling (FEM) and fully micromagnetic modeling results of four prototypical writers for perpendicular recording. In general, the agreement between the two models is quite good in the vicinity of saturated or near-saturated magnetic material, such as the pole tip, for quantities such as the magnetic field, the gradient of the magnetic field and the write width. However, in the vicinity of magnetic material far from saturation, e.g., return pole or trailing edge write shield, there can be large qualitative and quantitative differences.

  9. Theoretical tool movement required to diamond turn an off-axis paraboloid on axis

    International Nuclear Information System (INIS)

    Thompson, D.C.

    1975-01-01

    High-quality, off-axis parabolic reflectors, required by the CTR and laser-fusion programs at Lawrence Livermore Laboratory (LLL) and other ERDA laboratories, are currently manufactured by hand. There are several drawbacks to this method, including lead times of up to a year, costs in excess of dollars 75,000 for a small reflector, and unsatisfactory limits to the tolerances obtainable. This situation has led to a search for cheaper and more accurate methods of manufacturing off-axis paraboloids. An alternative method, turning the workpiece about its axis on a diamond-turning machine, is presented, and the equations describing the necessary tool movement are derived. A discussion of a particular case suggests that the proposed technique is feasible

  10. Stability of the thermodynamic equilibrium - A test of the validity of dynamic models as applied to gyroviscous perpendicular magnetohydrodynamics

    Science.gov (United States)

    Faghihi, Mustafa; Scheffel, Jan; Spies, Guenther O.

    1988-05-01

    Stability of the thermodynamic equilibrium is put forward as a simple test of the validity of dynamic equations, and is applied to perpendicular gyroviscous magnetohydrodynamics (i.e., perpendicular magnetohydrodynamics with gyroviscosity added). This model turns out to be invalid because it predicts exponentially growing Alfven waves in a spatially homogeneous static equilibrium with scalar pressure.

  11. Stability of the thermodynamic equilibrium: A test of the validity of dynamic models as applied to gyroviscous perpendicular magnetohydrodynamics

    International Nuclear Information System (INIS)

    Faghihi, M.; Scheffel, J.; Spies, G.O.

    1988-01-01

    Stability of the thermodynamic equilibrium is put forward as a simple test of the validity of dynamic equations, and is applied to perpendicular gyroviscous magnetohydrodynamics (i.e., perpendicular magnetohydrodynamics with gyroviscosity added). This model turns out to be invalid because it predicts exponentially growing Alfven waves in a spatially homogeneous static equilibrium with scalar pressure

  12. Perpendicular magnetic tunnel junction with thin CoFeB/Ta/Co/Pd/Co reference layer

    Energy Technology Data Exchange (ETDEWEB)

    Gan, Huadong, E-mail: huadong@avalanche-technology.com; Malmhall, Roger; Wang, Zihui; Yen, Bing K; Zhang, Jing; Wang, Xiaobin; Zhou, Yuchen; Hao, Xiaojie; Jung, Dongha; Satoh, Kimihiro; Huai, Yiming [Avalanche Technology, 46600 Landing Parkway, Fremont, California 94538 (United States)

    2014-11-10

    Integration of high density spin transfer torque magnetoresistance random access memory requires a thin stack (less than 15 nm) of perpendicular magnetic tunnel junction (p-MTJ). We propose an innovative approach to solve this challenging problem by reducing the thickness and/or moment of the reference layer. A thin reference layer structure of CoFeB/Ta/Co/Pd/Co has 60% magnetic moment of the conventional thick structure including [Co/Pd] multilayers. We demonstrate that the perpendicular magnetization of the CoFeB/Ta/Co/Pd/Co structure can be realized by anti-ferromagnetically coupling to a pinned layer with strong perpendicular anisotropy via Ruderman-Kittel-Kasuya-Yosida exchange interaction. The pMTJ with thin CoFeB/Ta/Co/Pd/Co reference layer has a comparable TMR ratio (near 80%) as that with thick reference layer after annealing at 280 °C. The pMTJ with thin reference layer has a total thickness less than 15 nm, thereby significantly increasing the etching margin required for integration of high density pMTJ array on wafers with form factor of 300 mm and beyond.

  13. Temperature dependence of microwave oscillations in magnetic tunnel junctions with a perpendicularly magnetized free layer

    International Nuclear Information System (INIS)

    Guo, Peng; Feng, Jiafeng; Wei, Hongxiang; Han, Xiufeng; Fang, Bin; Zhang, Baoshun; Zeng, Zhongming

    2015-01-01

    We experimentally study the temperature dependence of the spin-transfer-torque-induced microwave oscillations in MgO-based magnetic tunnel junction nanopillars with a perpendicularly magnetized free layer. We demonstrate that the oscillation frequency increases rapidly with decreasing temperature, which is mainly ascribed to the temperature dependence of both the saturation magnetization and the perpendicular magnetic anisotropy. We also find that a strong temperature dependence of the output power while a nonmonotonic temperature dependence of spectral linewidth are maintained for a constant dc bias in measured temperature range. Possible mechanisms leading to the different dependences of oscillation frequency, output power, and linewidth are discussed

  14. UMAPRM: Uniformly sampling the medial axis

    KAUST Repository

    Yeh, Hsin-Yi Cindy

    2014-05-01

    © 2014 IEEE. Maintaining clearance, or distance from obstacles, is a vital component of successful motion planning algorithms. Maintaining high clearance often creates safer paths for robots. Contemporary sampling-based planning algorithms That utilize The medial axis, or The set of all points equidistant To Two or more obstacles, produce higher clearance paths. However, They are biased heavily Toward certain portions of The medial axis, sometimes ignoring parts critical To planning, e.g., specific Types of narrow passages. We introduce Uniform Medial Axis Probabilistic RoadMap (UMAPRM), a novel planning variant That generates samples uniformly on The medial axis of The free portion of Cspace. We Theoretically analyze The distribution generated by UMAPRM and show its uniformity. Our results show That UMAPRM\\'s distribution of samples along The medial axis is not only uniform but also preferable To other medial axis samplers in certain planning problems. We demonstrate That UMAPRM has negligible computational overhead over other sampling Techniques and can solve problems The others could not, e.g., a bug Trap. Finally, we demonstrate UMAPRM successfully generates higher clearance paths in The examples.

  15. Effect of grain boundary phase on the magnetization reversal process of nanocrystalline magnet using large-scale micromagnetic simulation

    Directory of Open Access Journals (Sweden)

    Hiroshi Tsukahara

    2018-05-01

    Full Text Available We investigated the effects of grain boundary phases on magnetization reversal in permanent magnets by performing large-scale micromagnetic simulations based on Landau–Lifshitz–Gilbert equation under a periodic boundary. We considered planar grain boundary phases parallel and perpendicular to an easy axis of the permanent magnet and assumed the saturation magnetization and exchange stiffness constant of the grain boundary phase to be 10% and 1%, respectively, for Nd2Fe14B grains. The grain boundary phase parallel to the easy axis effectively inhibits propagation of magnetization reversal. In contrast, the domain wall moves across the grain boundary perpendicular to the easy axis. These properties of the domain wall motion are explained by dipole interaction, which stabilizes the antiparallel magnetic configuration in the direction perpendicular to the magnetization orientation. On the other hand, the magnetization is aligned in the same direction by the dipole interaction parallel to the magnetization orientation. This anisotropy of the effect of the grain boundary phase shows that improvement of the grain boundary phase perpendicular to the easy axis effectively enhances the coercivity of permanent magnets.

  16. AC bias operation of the perpendicular biased ferrite tuned cavity for the TRIUMF KAON Factory booster synchrotron

    International Nuclear Information System (INIS)

    Poirier, R.L.; Enegren, T.A.; Enchevich, I.B.

    1991-05-01

    The RF cavity for the booster synchrotron requires a frequency swing from 46 MHz at a repetition rate of 50 Hz and a maximum accelerating gap voltage of 65 kV. A DC biased prototype cavity built at LANL using perpendicular-biased yttrium-garnet ferrites, rather than the more conventional parallel-biased NiZn ferrites, has now undergone major reconstruction at TRIUMF for AC bias operation. RF signal level measurements have shown that the frequency swing at a repetition rate of 50 Hz can be accomplished and still handle the eddy current losses in the cavity structures with minimal effect on the magnetizing field. The prototype cavity is now undergoing high power RF tests with full power AC bias operation. The results of these tests and operational experience is reported. (Author) ref., 6 figs

  17. Role of an ultrathin platinum seed layer in antiferromagnet-based perpendicular exchange coupling and its electrical manipulation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y.Y., E-mail: wangyy@buaa.edu.cn [Department of Physics, Beihang University, Beijing 100191 (China); Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Song, C., E-mail: songcheng@mail.tsinghua.edu.cn [Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Zhang, J.Y. [Department of Physics, Beihang University, Beijing 100191 (China); Pan, F. [Key Laboratory of Advanced Materials (MOE), School of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)

    2017-04-15

    The requirement for low-power consumption advances the development of antiferromagnetic (AFM) spintronics manipulated by electric fields. Here we report an electrical manipulation of metallic AFM moments within IrMn/[Co/Pt] by interface engineering, where ultrathin non-magnetic metals are highlighted between IrMn and ferroelectric substrates. Ultrathin Pt seed layers are proved to be vital in elevating the blocking temperature and enhancing the perpendicular exchange coupling through modulating the domain structures of as-prepared IrMn AFM. Further electrical manipulations of perpendicular magnetic anisotropy crucially verify the indispensable role of pre-deposited ultrathin Pt layers in modulating IrMn antiferromagnetic moments, which is confirmed by the intimate correlation between the electrically manipulating AFM and improving its blocking temperature. Instead of immediate contact between IrMn AFM and ferroelectric substrates in a conventional way, interface engineering by adopting ultrathin seed layers here adds a new twist to the electrical modulation of AFM metals. This would provide scientific basis on how to manipulate AFM moments and optimize the design of practical AFM spintronics. - Highlights: • An alternative for manipulating antiferromagnet by interface engineering is provided. • Ultrathin Pt seed layers are vital in elevating the blocking temperature of IrMn. • Perpendicular exchange coupling in IrMn/[Co/Pt] can be modulated by seed layers. • Ultrathin Pt seed layers enable electrical control of perpendicular exchange coupling.

  18. Role of an ultrathin platinum seed layer in antiferromagnet-based perpendicular exchange coupling and its electrical manipulation

    International Nuclear Information System (INIS)

    Wang, Y.Y.; Song, C.; Zhang, J.Y.; Pan, F.

    2017-01-01

    The requirement for low-power consumption advances the development of antiferromagnetic (AFM) spintronics manipulated by electric fields. Here we report an electrical manipulation of metallic AFM moments within IrMn/[Co/Pt] by interface engineering, where ultrathin non-magnetic metals are highlighted between IrMn and ferroelectric substrates. Ultrathin Pt seed layers are proved to be vital in elevating the blocking temperature and enhancing the perpendicular exchange coupling through modulating the domain structures of as-prepared IrMn AFM. Further electrical manipulations of perpendicular magnetic anisotropy crucially verify the indispensable role of pre-deposited ultrathin Pt layers in modulating IrMn antiferromagnetic moments, which is confirmed by the intimate correlation between the electrically manipulating AFM and improving its blocking temperature. Instead of immediate contact between IrMn AFM and ferroelectric substrates in a conventional way, interface engineering by adopting ultrathin seed layers here adds a new twist to the electrical modulation of AFM metals. This would provide scientific basis on how to manipulate AFM moments and optimize the design of practical AFM spintronics. - Highlights: • An alternative for manipulating antiferromagnet by interface engineering is provided. • Ultrathin Pt seed layers are vital in elevating the blocking temperature of IrMn. • Perpendicular exchange coupling in IrMn/[Co/Pt] can be modulated by seed layers. • Ultrathin Pt seed layers enable electrical control of perpendicular exchange coupling.

  19. Perpendicular Magnetic Anisotropy in Heusler Alloy Films and Their Magnetoresistive Junctions

    Directory of Open Access Journals (Sweden)

    Atsufumi Hirohata

    2018-01-01

    Full Text Available For the sustainable development of spintronic devices, a half-metallic ferromagnetic film needs to be developed as a spin source with exhibiting 100% spin polarisation at its Fermi level at room temperature. One of the most promising candidates for such a film is a Heusler-alloy film, which has already been proven to achieve the half-metallicity in the bulk region of the film. The Heusler alloys have predominantly cubic crystalline structures with small magnetocrystalline anisotropy. In order to use these alloys in perpendicularly magnetised devices, which are advantageous over in-plane devices due to their scalability, lattice distortion is required by introducing atomic substitution and interfacial lattice mismatch. In this review, recent development in perpendicularly-magnetised Heusler-alloy films is overviewed and their magnetoresistive junctions are discussed. Especially, focus is given to binary Heusler alloys by replacing the second element in the ternary Heusler alloys with the third one, e.g., MnGa and MnGe, and to interfacially-induced anisotropy by attaching oxides and metals with different lattice constants to the Heusler alloys. These alloys can improve the performance of spintronic devices with higher recording capacity.

  20. Surfing and drift acceleration at high mach number quasi-perpendicular shocks

    International Nuclear Information System (INIS)

    Amano, T.

    2008-01-01

    Electron acceleration in high Mach number collisionless shocks relevant to supernova remnant is discussed. By performing one- and two-dimensional particle-in-cell simulations of quasi-perpendicular shocks, we find that energetic electrons are quickly generated in the shock transition region through shock surfing and drift acceleration. The electron energization is strong enough to account for the observed injection at supernova remnant shocks. (author)

  1. CeCo5 thin films with perpendicular anisotropy grown by molecular beam epitaxy

    Science.gov (United States)

    Sharma, S.; Hildebrandt, E.; Major, M.; Komissinskiy, P.; Radulov, I.; Alff, L.

    2018-04-01

    Buffer-free, highly textured (0 0 1) oriented CeCo5 thin films showing perpendicular magnetic anisotropy were synthesized on (0 0 1) Al2O3 substrates by molecular beam epitaxy. Ce exists in a mixture of Ce3+ and Ce4+ valence states as shown by X-ray photoelectron spectroscopy. The first anisotropy constant, K1, as measured by torque magnetometry was 0.82 MJ/m3 (8.2 ×106erg /cm3) . A maximum coercivity of 5.16 kOe with a negative temperature coefficient of -0.304%K-1 and a magnetization of 527.30 emu/cm3 was measured perpendicular to the film plane at 5 K. In addition, a large anisotropy of the magnetic moment of 15.5% was observed. These magnetic parameters make CeCo5 a potential candidate material for spintronic and magnetic recording applications.

  2. Thermal fluctuations in perpendicular recording media: New methodology for estimation of activation moment

    International Nuclear Information System (INIS)

    Mamiya, H; Oba, Y; Ohnuma, M; Hagiya, H; Oku, T; Suzuki, J; Yokoyama, M; Nishihara, Y; Katayama, T; Awano, H; Koda, T

    2011-01-01

    In nanoparticulate films with perpendicular magnetic anisotropy, a large demagnetizing field almost compensates for the experimentally designed change in the magnetic field applied parallel to the film normal. We propose a new method based on field-cycling to eliminate the uncertainty in the demagnetizing response from the analysis of the activation volume of the reversal or magnetic activation moment in such films. In this method, the applied field induced variation in the magnetic relaxation rate is measured before the effect of the demagnetizing field becomes dominant. We also discuss an analogical thermal-cycling method to clarify the temperature dependence of the barrier height for magnetization reversal in a magnetic field. We apply these methods to a Co 74 Pt 16 Cr 10 -SiO 2 nanoparticulate film as an example. The results demonstrate that these methods are useful for studying thermal fluctuations in perpendicular recording media.

  3. Evolution of hypothalamus-pituitary growth axis among fish, amphibian, birds and mammals

    Directory of Open Access Journals (Sweden)

    Moaeen-Ud-Din M.

    2015-01-01

    Full Text Available Hypothalamus-pituitary growth axis (HP growth axis regulates animal growth and development in pre-natal and post natal life governed by many factors. However, until recently, the evolutionary history of this axis among lineages is not understood. Aim of the present study was to understand the major events in evolution and evolutionary history and trend of HP growth axis. The diversity among Homo sapience, Mus musculus, Rattus norvegicus, Gallus gallus, Danio rerio and Xenopus laevis was determined for genes involved in HP growth axis in current study. Sequences of HP growth axis genes were retrieved from NCBI (http://www.ncbi.nlm.nih.gov/. Nucleotide diversity using Kimura’s two-parameter method; codon-based test of positive selection using the Nei-Gojobori; equality of evolutionary rate with Tajima's relative rate test and phylogenetic history using the RelTime method were estimated in MEGA6. Estimates of the coefficients of evolutionary differentiation based on nucleotides and amino acids substitution patterns of HP growth axis genes showed contrasting evolutionary patterns among the lineages. The results demonstrated that although these genes might have crucial functional roles in each of the species, however, their sequence divergence did not necessarily reflect similar molecular evolution among the species. Codon-based test of positive selection revealed that Human vs Mouse, Chicken vs Rat, Human vs Rat and Mouse vs Rat had similar and higher non synonymous substitutions (P > 0.05. Higher rate of non-synonymous substitutions at similar orthologs level among species indicated a similar positive selection pressure in these species. Results for relative rate test assessed with the chi-squared test showed difference on unique mutations among lineages at synonymous and non synonymous sites except Chicken vs Mouse, Human vs Mouse, Chicken vs Rat, Human vs Rat and Mouse vs Rat. This indicated that the mutagenic process that generates

  4. Modulation of the Hypothalamic-Pituitary-Adrenal Axis by Early Life Stress Exposure

    Science.gov (United States)

    van Bodegom, Miranda; Homberg, Judith R.; Henckens, Marloes J. A. G.

    2017-01-01

    hyper-reactivity in adulthood, as also found in major depression. This hyper-activity is related to increased corticotrophin-releasing hormone signaling and impaired glucocorticoid receptor-mediated negative feedback. In contrast, initial evidence for HPA-axis hypo-reactivity is observed for early social deprivation, potentially reflecting the abnormal HPA-axis function as observed in post-traumatic stress disorder, and future studies should investigate its neural/neuroendocrine foundation in further detail. Interestingly, experiencing additional (chronic) stress in adulthood seems to normalize these alterations in HPA-axis function, supporting the match/mismatch theory. PMID:28469557

  5. A cytokine axis regulates elastin formation and degradation

    Science.gov (United States)

    Sproul, Erin P.; Argraves, W. Scott

    2013-01-01

    Underlying the dynamic regulation of tropoelastin expression and elastin formation in development and disease are transcriptional and post-transcriptional mechanisms that have been the focus of much research. Of particular importance is the cytokine–governed elastin regulatory axis in which the pro-elastogenic activities of transforming growth factor β-1 (TGFβ1) and insulin-like growth factor-I (IGF-I) are opposed by anti-elastogenic activities of basic fibroblast growth factor (bFGF/FGF-2), heparin-binding epidermal growth factor-like growth factor (HB-EGF), EGF, PDGF-BB, TGFα, tumor necrosis factor-alpha (TNF-α), interleukin (IL)-1β and noncanonical TGFβ1 signaling. A key mechanistic feature of the regulatory axis is that cytokines influence elastin formation through effects on the cell cycle involving control of cyclin–cyclin dependent kinase complexes and activation of the Ras/MEK/ERK signaling pathway. In this article we provide an overview of the major cytokines/growth factors that modulate elastogenesis and describe the underlying molecular mechanisms for their action on elastin production. PMID:23160093

  6. High-Q perpendicular-biased ferrite-tuned cavity

    International Nuclear Information System (INIS)

    Carlini, R.D.; Thiessen, H.A.; Potter, J.M.

    1983-01-01

    Rapid-cycling proton synchrotrons, such as the proposed LAMPF II accelerator, require approximately 10 MV per turn rf with 17% tuning range near 50 MHz. The traditional approach to ferrite-tuned cavities uses a ferrite which is longitudinally biased (rf magnetic field parallel to bias field). This method leads to unacceptably high losses in the ferrite. At Los Alamos, we are developing a cavity with transverse bias (rf magnetic field perpendicular to the bias field) that makes use of the tensor permeability of the ferrite. Modest power tests of a small (10-cm-dia) quarter-wave singly re-entrant cavity tuned by nickel-zinc ferrites and aluminum-doped garnets indicate that the losses in the ferrite can be made negligible compared with the losses due to the surface resistivity of the copper cavity at power levels from 2 to 200 watts

  7. Charged particle beam scanning using deformed high gradient insulator

    Science.gov (United States)

    Chen, Yu -Jiuan

    2015-10-06

    Devices and methods are provided to allow rapid deflection of a charged particle beam. The disclosed devices can, for example, be used as part of a hadron therapy system to allow scanning of a target area within a patient's body. The disclosed charged particle beam deflectors include a dielectric wall accelerator (DWA) with a hollow center and a dielectric wall that is substantially parallel to a z-axis that runs through the hollow center. The dielectric wall includes one or more deformed high gradient insulators (HGIs) that are configured to produce an electric field with an component in a direction perpendicular to the z-axis. A control component is also provided to establish the electric field component in the direction perpendicular to the z-axis and to control deflection of a charged particle beam in the direction perpendicular to the z-axis as the charged particle beam travels through the hollow center of the DWA.

  8. Magnetization reversal mechanism of Nd-Fe-B films with perpendicular magnetic anisotropy

    International Nuclear Information System (INIS)

    Liu Xiaoxi; Ishida, Go; Morisako, Akimitsu

    2011-01-01

    The microstructure and magnetic properties of Nd-Fe-B films with thicknesses from 100 nm to 3 nm have been investigated. All the films show excellent perpendicular magnetic anisotropy with a squareness ratio of 1 in the perpendicular direction and almost zero coercivity in the in-plane direction. Of particular interest is that the initial magnetization curves sensitively depended on the film thickness. Films thicker than 15 nm show steep initial magnetization curve. Although the films have coercivities larger than 21 kOe, the films can be fully magnetized from the thermally demagnetized state with a field as small as 5 kOe. With the decrease of film thickness to 5 nm, the initial magnetization curve becomes flat. The evolution of initial magnetization curves with film thickness can be understood by the microstructure of the films. Films with thickness of 15 nm show close-packed grains without any intergranular phases. Such microstructures lead to steep initial magnetization curves. On the other hand, when the film thickness decreased to 3 nm, the film thickness became nonuniform. Such microstructure leads to flat initial magnetization curves.

  9. Voltage fluctuations in granular superconductors in the perpendicular configuration

    International Nuclear Information System (INIS)

    Gerashchenko, O V

    2003-01-01

    The spectral density of voltage fluctuations in granular YBa 2 Cu 3 O 7-δ superconductors in the perpendicular configuration has been studied in the flux flow mode. It has been found that, in this case, the 1/f-voltage noise observed depends weakly on temperature and is associated with motion of a magnetic flux in the superconductor. A comparison of the data obtained with the results of previous measurements in parallel configuration has shown that voltage noise is produced by a single common source, which is presumably associated with self-organization of the critical state in granular superconductors

  10. Current perpendicular to plane giant magnetoresistance in laminated nanostructures

    International Nuclear Information System (INIS)

    Vedyayev, A.; Zhukov, I.; Dieny, B.

    2005-01-01

    We theoretically studied spin-dependent electron transport perpendicular-to-plain (CPP) in magnetic laminated multilayered structures by using Kubo formalism. We took into account not only bulk scattering, but the interface resistance due to both specular and diffuse reflection and also spin conserving and spin-flip processes. It was shown that spin-flip scattering at interfaces substantially reduces the value of giant magnetoresistance (GMR). This can explain the experimental observations that the CPP GMR ratio for laminated structures only slightly increases as compared to non-laminated ones even though lamination induces a significant increase in CPP resistance

  11. The effects of axis ratio on laminar fluid flow around an elliptical cylinder

    International Nuclear Information System (INIS)

    Faruquee, Zakir; Ting, David S-K.; Fartaj, Amir; Barron, Ronald M.; Carriveau, Rupp

    2007-01-01

    An elliptical cylinder is a generic shape which represents a flat plate at its minor to major axis ratio (AR) limits of zero and infinity, and a circular cylinder at AR of unity. While incompressible flows over a streamwise flat plate (AR = 0), a cross-stream flat plate (AR = ∞), and a circular cylinder have been studied extensively, the role of AR on the detailed flow structure is still not well understood. Therefore, a numerical study was conducted to examine the flow field around an elliptical cylinder over a range of ARs from 0.3 to 1, with the major axis parallel to the free-stream, at a Reynolds number of 40 based on the hydraulic diameter. The control volume approach of FLUENT was used to solve the fluid flow equations, assuming the flow over the cylinder is unbounded, steady, incompressible and two-dimensional. It has been found that a pair of steady vortices forms when AR reaches a critical value of 0.34; below this value no vortices are formed behind the elliptical cylinder. Various wake parameters, drag coefficient, pressure and velocity distributions, have been characterized as functions of AR. The wake size and the drag coefficient are found to increase with the increase of AR. Quadratic correlations have been obtained to describe the relations of wake length and drag coefficient with axis ratio

  12. Grab structure of a lifting structure in particular for use in a nuclear reactor for lifting and lowering of fuel elements and fuel rods

    International Nuclear Information System (INIS)

    Dose, G.

    1979-01-01

    A guide tower projects perpendicularly downward from the carriage of the charging machine. It can be rotated about its perpendicular axis. The tower is used to displace a hollow grab structure with two grabs. They can be opened and closed, the closed position being retained as long as they carry the fuel elements or rods. The power and interlocking equipment is installed one unit above the other in the joint grab housing. The tower with the integrated fuel element grab and the rod grab is rotated about its perpendicular axis for inspection of the fuel elements or rods. (DG) [de

  13. Fully differential cross sections for low to intermediate energy perpendicular plane ionization of xenon atoms

    Energy Technology Data Exchange (ETDEWEB)

    Purohit, G., E-mail: ghanshyam.purohit@spsu.ac.in; Singh, P.; Patidar, V.

    2014-12-15

    Highlights: • We present triply differential cross section (TDCS) results for the perpendicular plane ionization of xenon atoms. • The TDCS has been calculated in the modified distorted wave Born approximation formalism. • The effects of target polarization and post collision interaction have also been included. • The polarization potential, higher order effects and PCI has been found to be useful in the description of TDCS. - Abstract: Triple differential cross section (TDCS) results are reported for the perpendicular plane ionization of Xe (5p) at incident electron energies 5 eV, 10 eV, 20 eV, and 40 eV above ionization potential. The modified distorted wave Born approximation formalism with first as well as the second order Born terms has been used to calculate the TDCS. Effects of target polarization and post collision interaction have also been included. We compare the (e, 2e) TDCS results of our calculation with the recent available experimental data and theoretical results and discuss the process contributing to structure seen in the differential cross section. It has been observed from the present study that the second order effect and target polarization make significant contribution in description of collision dynamics of xenon at the low and intermediate energy for the perpendicular emission of electrons.

  14. Fully differential cross sections for low to intermediate energy perpendicular plane ionization of xenon atoms

    International Nuclear Information System (INIS)

    Purohit, G.; Singh, P.; Patidar, V.

    2014-01-01

    Highlights: • We present triply differential cross section (TDCS) results for the perpendicular plane ionization of xenon atoms. • The TDCS has been calculated in the modified distorted wave Born approximation formalism. • The effects of target polarization and post collision interaction have also been included. • The polarization potential, higher order effects and PCI has been found to be useful in the description of TDCS. - Abstract: Triple differential cross section (TDCS) results are reported for the perpendicular plane ionization of Xe (5p) at incident electron energies 5 eV, 10 eV, 20 eV, and 40 eV above ionization potential. The modified distorted wave Born approximation formalism with first as well as the second order Born terms has been used to calculate the TDCS. Effects of target polarization and post collision interaction have also been included. We compare the (e, 2e) TDCS results of our calculation with the recent available experimental data and theoretical results and discuss the process contributing to structure seen in the differential cross section. It has been observed from the present study that the second order effect and target polarization make significant contribution in description of collision dynamics of xenon at the low and intermediate energy for the perpendicular emission of electrons

  15. Determination of a sagittal plane axis of rotation for a dynamic office chair.

    Science.gov (United States)

    Bauer, C M; Rast, F M; Böck, C; Kuster, R P; Baumgartner, D

    2018-10-01

    This study investigated the location of the axis of rotation in sagittal plane movement of the spine in a free sitting condition to adjust the kinematics of a mobile seat for a dynamic chair. Dynamic office chairs are designed to avoid continuous isometric muscle activity, and to facilitate increased mobility of the back during sitting. However, these chairs incorporate increased upper body movement which could distract office workers from the performance of their tasks. A chair with an axis of rotation above the seat would facilitate a stable upper back during movements of the lower back. The selection of a natural kinematic pattern is of high importance in order to match the properties of the spine. Twenty-one participants performed four cycles of flexion and extension of the spine during an upper arm hang on parallel bars. The location of the axis of rotation relative to the seat was estimated using infrared cameras and reflective skin markers. The median axis of rotation across all participants was located 36 cm above the seat for the complete movement and 39 cm for both the flexion and extension phases, each with an interquartile range of 20 cm. There was no significant effect of the movement direction on the location of the axis of rotation and only a weak, non-significant correlation between body height and the location of the axis of rotation. Individual movement patterns explained the majority of the variance. The axis of rotation for a spinal flexion/extension movement is located above the seat. The recommended radius for a guide rail of a mobile seat is between 36 cm and 39 cm. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. Brake lock mechanism for the two axis pointing system

    Science.gov (United States)

    Posey, Alan; Clark, Mike; Mignosa, Larry

    1991-01-01

    Six months prior to shipment of the Broadband X-ray Telescope to the Kennedy Space Center for flight aboard the Space Shuttle Columbia, a major system failure occurred. During modal survey testing of the telescope's gimbal pointing system, the roll axis brake unexpectedly released. Low level vibration and static preloads present during the modal survey were within the expected flight environment. Brake release during shuttle liftoff or ascent was an unacceptable risk to mission success; thus, a Brake Lock Mechanism (BLM) was developed.

  17. Simple Analytical Forms of the Perpendicular Diffusion Coefficient for Two-component Turbulence. III. Damping Model of Dynamical Turbulence

    Energy Technology Data Exchange (ETDEWEB)

    Gammon, M.; Shalchi, A., E-mail: andreasm4@yahoo.com [Department of Physics and Astronomy, University of Manitoba, Winnipeg, Manitoba R3T 2N2 (Canada)

    2017-10-01

    In several astrophysical applications one needs analytical forms of cosmic-ray diffusion parameters. Some examples are studies of diffusive shock acceleration and solar modulation. In the current article we explore perpendicular diffusion based on the unified nonlinear transport theory. While we focused on magnetostatic turbulence in Paper I, we included the effect of dynamical turbulence in Paper II of the series. In the latter paper we assumed that the temporal correlation time does not depend on the wavenumber. More realistic models have been proposed in the past, such as the so-called damping model of dynamical turbulence. In the present paper we derive analytical forms for the perpendicular diffusion coefficient of energetic particles in two-component turbulence for this type of time-dependent turbulence. We present new formulas for the perpendicular diffusion coefficient and we derive a condition for which the magnetostatic result is recovered.

  18. Ammonia toroid aligned perpendicular to the HH 1 and HH 2 bipolar outflow

    International Nuclear Information System (INIS)

    Torrelles, J.M.; Canto, J.; Rodriguez, L.F.; Ho, P.T.P.; Moran, J.M.; Universidad Nacional Autonoma de Mexico, Mexico City)

    1985-01-01

    The ammonia emission from the region containing the Herbig-Haro objects 1 and 2, which mark the presence of a bipolar outflow, was mapped. The ammonia observations delineate an elongated structure aligned perpendicular to the bipolar outflow. This ammonia condensation is centered between HH 1 and HH 2 and coincides with the recently discovered central radio continuum source. This continuum source has no optical counterpart. The ammonia spectrum at the position of the continuum source shows a remarkable splitting. Based on the orientation of the bipolar outflow, which is known to be oriented nearly perpendicular to the line of sight, and on theoretical considerations, it is concluded that the ammonia source is part of a toroid, viewed edge-on, in slow expansion driven by the wind pressure of the central source. This toroid may be the focusing mechanism for the bipolar outflow. Searches for ammonia condensations in the vicinity of other HH objects may help localize the energy sources of these systems. 26 references

  19. Effect of Grafting Density of Random Copolymer Brushes on Perpendicular Alignment in PS-b-PMMA Thin Films

    KAUST Repository

    Lee, Wooseop; Park, Sungmin; Kim, Yeongsik; Sethuraman, Vaidyanathan; Rebello, Nathan; Ganesan, Venkat; Ryu, Du Yeol

    2017-01-01

    We modulated the grafting density (σ) of a random copolymer brush of poly(styrene-r-methyl methacrylate) on substrates to probe its effect on the formation of perpendicularly aligned lamellae of polystyrene-b-poly(methyl methacrylate) (PS-b-PMMA). Supported by coarse-grained simulation results, we hypothesized that an increase in σ will allow us to systematically tune the block copolymer interfacial interactions with the substrates from being preferential to one of the blocks to being neutral toward both blocks and will thereby facilitate enhanced regimes of perpendicularly aligned lamellae. We verified such a hypothesis by using a simple grafting-to approach to modify the substrates and characterized the thickness window for perpendicular lamellae as a function of brush thickness (or σ) on the grafted substrates using scanning force microscopy (SFM) images and grazing incidence small-angle X-ray scattering (GISAXS) measurements. The experimental results validated our hypothesis and suggested that the σ of random copolymer brushes can be used as an additional versatile parameter to modulate the interfacial interactions and the resulting alignment of block copolymer films.

  20. Effect of Grafting Density of Random Copolymer Brushes on Perpendicular Alignment in PS-b-PMMA Thin Films

    KAUST Repository

    Lee, Wooseop

    2017-07-18

    We modulated the grafting density (σ) of a random copolymer brush of poly(styrene-r-methyl methacrylate) on substrates to probe its effect on the formation of perpendicularly aligned lamellae of polystyrene-b-poly(methyl methacrylate) (PS-b-PMMA). Supported by coarse-grained simulation results, we hypothesized that an increase in σ will allow us to systematically tune the block copolymer interfacial interactions with the substrates from being preferential to one of the blocks to being neutral toward both blocks and will thereby facilitate enhanced regimes of perpendicularly aligned lamellae. We verified such a hypothesis by using a simple grafting-to approach to modify the substrates and characterized the thickness window for perpendicular lamellae as a function of brush thickness (or σ) on the grafted substrates using scanning force microscopy (SFM) images and grazing incidence small-angle X-ray scattering (GISAXS) measurements. The experimental results validated our hypothesis and suggested that the σ of random copolymer brushes can be used as an additional versatile parameter to modulate the interfacial interactions and the resulting alignment of block copolymer films.

  1. Anterior fixation of the axis.

    Science.gov (United States)

    Traynelis, Vincent C; Fontes, Ricardo B V

    2010-09-01

    Although anterior fixation of the axis is not commonly performed, plate fixation of C2 is an important technique for treating select upper cervical traumatic injuries and is also useful in the surgical management of spondylosis. To report the technique and outcomes of C2 anterior plate fixation for a series of patients in which the majority presented with symptomatic degenerative spondylosis. Forty-six consecutive patients underwent single or multilevel fusions over a 7-year period; 30 of these had advanced degenerative disease manifested by myelopathy or deformity. Exposure was achieved with rostral extension of the standard anterior cervical exposure via careful soft tissue dissection, mobilization of the superior thyroid artery, and the use of a table-mounted retractor. It was not necessary to remove the submandibular gland, section the digastric muscle, or make additional skin incisions. Screws were placed an average of 4.6 mm (+/- 2.3 mm) from the inferior C2 endplate with a mean sagittal trajectory of 15.7 degrees (+/- 7.6 degrees). Short- and long-term procedure-related mortality was 4.4%, and perioperative morbidity was 8.9%. Patients remained intubated an average of 2.5 days following surgery. Dysphagia was initially reported by 15.2% of patients but resolved by the 8th postoperative week in all patients. Arthrodesis was achieved in all patients available for long-term follow-up. Multilevel fusions were not associated with longer hospitalization or morbidity. Anterior plate fixation of the axis for degenerative disease can be accomplished with acceptable morbidity employing an extension of the standard anterolateral route.

  2. THE ACCRETION OF DARK MATTER SUBHALOS WITHIN THE COSMIC WEB: PRIMORDIAL ANISOTROPIC DISTRIBUTION AND ITS UNIVERSALITY

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Xi; Wang, Peng, E-mail: kangxi@pmo.ac.cn [Purple Mountain Observatory, the Partner Group of MPI für Astronomie, 2 West Beijing Road, Nanjing 210008 (China)

    2015-11-01

    The distribution of galaxies displays anisotropy on different scales and it is often referred to as galaxy alignment. To understand the origin of galaxy alignments on small scales, one must investigate how galaxies were accreted in the early universe and quantify their primordial anisotropy at the time of accretion. In this paper we use N-body simulations to investigate the accretion of subhalos, focusing on their alignment with halo shape and the orientation of mass distribution on the large scale, defined using the Hessian matrix of the density field. The large/small (e1/e3) eigenvalues of the Hessian matrix define the fast/slow collapse direction of matter on the large scale. We find that: (1) the halo major axis is well aligned with the e3 (slow collapse) direction, and it is stronger for massive halos; (2) subhalos are predominantly accreted along the major axis of the host halo, and the alignment increases with the host halo mass. Most importantly, this alignment is universal; (3) accretion of subhalos with respect to the e3 direction is not universal. In massive halos, subhalos are accreted along the e3 (even more strongly than the alignment with the halo major axis), but in low-mass halos subhalos are accreted perpendicular to e3. The transitional mass is lower at high redshift. The last result well explains the puzzling correlation (both in recent observations and simulations) that massive galaxies/halos have their spin perpendicular to the filament, and the spin of low-mass galaxies/halos is slightly aligned with the filament, under the assumption that the orbital angular momentum of subhalos is converted to halo spin.

  3. ALMA Dust Polarization Observations of Two Young Edge-on Protostellar Disks

    Science.gov (United States)

    Lee, Chin-Fei; Li, Zhi-Yun; Ching, Tao-Chung; Lai, Shih-Ping; Yang, Haifeng

    2018-02-01

    Polarized emission is detected in two young nearly edge-on protostellar disks in 343 GHz continuum at ∼50 au (∼0.″12) resolution with Atacama Large Millimeter/submillimeter Array. One disk is in HH 212 (Class 0) and the other in the HH 111 (early Class I) protostellar system. The polarization fraction is ∼1%. The disk in HH 212 has a radius of ∼60 au. The emission is mainly detected from the nearside of the disk. The polarization orientations are almost perpendicular to the disk major axis, consistent with either self-scattering or emission by grains aligned with a poloidal field around the outer edge of the disk because of the optical depth effect and temperature gradient; the presence of a poloidal field would facilitate the launching of a disk wind, for which there is already tentative evidence in the same source. The disk of HH 111 VLA 1 has a larger radius of ∼220 au and is thus more resolved. The polarization orientations are almost perpendicular to the disk major axis in the nearside, but more along the major axis in the farside, forming roughly half of an elliptical pattern there. It appears that toroidal and poloidal magnetic field may explain the polarization on the near and far sides of the disk, respectively. However, it is also possible that the polarization is due to self-scattering. In addition, alignment of dust grains by radiation flux may play a role in the farside. Our observations reveal a diversity of disk polarization patterns that should be taken into account in future modeling efforts.

  4. A Novel Method of Quantitative Anterior Chamber Depth Estimation Using Temporal Perpendicular Digital Photography.

    Science.gov (United States)

    Zamir, Ehud; Kong, George Y X; Kowalski, Tanya; Coote, Michael; Ang, Ghee Soon

    2016-07-01

    We hypothesize that: (1) Anterior chamber depth (ACD) is correlated with the relative anteroposterior position of the pupillary image, as viewed from the temporal side. (2) Such a correlation may be used as a simple quantitative tool for estimation of ACD. Two hundred sixty-six phakic eyes had lateral digital photographs taken from the temporal side, perpendicular to the visual axis, and underwent optical biometry (Nidek AL scanner). The relative anteroposterior position of the pupillary image was expressed using the ratio between: (1) lateral photographic temporal limbus to pupil distance ("E") and (2) lateral photographic temporal limbus to cornea distance ("Z"). In the first chronological half of patients (Correlation Series), E:Z ratio (EZR) was correlated with optical biometric ACD. The correlation equation was then used to predict ACD in the second half of patients (Prediction Series) and compared to their biometric ACD for agreement analysis. A strong linear correlation was found between EZR and ACD, R = -0.91, R 2 = 0.81. Bland-Altman analysis showed good agreement between predicted ACD using this method and the optical biometric ACD. The mean error was -0.013 mm (range -0.377 to 0.336 mm), standard deviation 0.166 mm. The 95% limits of agreement were ±0.33 mm. Lateral digital photography and EZR calculation is a novel method to quantitatively estimate ACD, requiring minimal equipment and training. EZ ratio may be employed in screening for angle closure glaucoma. It may also be helpful in outpatient medical clinic settings, where doctors need to judge the safety of topical or systemic pupil-dilating medications versus their risk of triggering acute angle closure glaucoma. Similarly, non ophthalmologists may use it to estimate the likelihood of acute angle closure glaucoma in emergency presentations.

  5. Vertical axis wind turbine airfoil

    Science.gov (United States)

    Krivcov, Vladimir; Krivospitski, Vladimir; Maksimov, Vasili; Halstead, Richard; Grahov, Jurij Vasiljevich

    2012-12-18

    A vertical axis wind turbine airfoil is described. The wind turbine airfoil can include a leading edge, a trailing edge, an upper curved surface, a lower curved surface, and a centerline running between the upper surface and the lower surface and from the leading edge to the trailing edge. The airfoil can be configured so that the distance between the centerline and the upper surface is the same as the distance between the centerline and the lower surface at all points along the length of the airfoil. A plurality of such airfoils can be included in a vertical axis wind turbine. These airfoils can be vertically disposed and can rotate about a vertical axis.

  6. Targeting the IL-33/IL-13 Axis for Respiratory Viral Infections.

    Science.gov (United States)

    Donovan, Chantal; Bourke, Jane E; Vlahos, Ross

    2016-04-01

    Lung diseases, such as asthma and chronic obstructive pulmonary disease (COPD), are highly prevalent worldwide. One of the major factors that limits the efficacy of current medication in these patients are viral infections, leading to exacerbations of symptoms and decreased quality of life. Current pharmacological strategies targeting virus-induced lung disease are problematic due to antiviral resistance and the requirement for strain-specific vaccination. Thus, new therapeutic strategies are urgently required. In this Opinion article, we provide state-of-the-art evidence from humans and preclinical animal models implicating the interleukin (IL)-33/IL-13 axis in virus-induced lung disease. Thus, targeting the IL-33/IL-13 axis may be a feasible way to overcome the limitations of current therapy used to treat virus-induced exacerbations of lung disease. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Compressive capacity perpendicular to grain of fully supported timber beams of Poplar - model comparison

    NARCIS (Netherlands)

    Leijten, A.J.M.; Haddad, Y.M.

    2015-01-01

    In timber frame structures, for both residential and multi-storey purposes, timber elements are loaded perpendicular to grain. In the past, structural design code calculations were based on pre-set permissible strength values, applying empirical models with obscure background. Modern ultimate limit

  8. Viscosity of two-dimensional strongly coupled dusty plasma modified by a perpendicular magnetic field

    Science.gov (United States)

    Feng, Yan; Lin, Wei; Murillo, M. S.

    2017-11-01

    Transport properties of two-dimensional (2D) strongly coupled dusty plasmas have been investigated in detail, but never for viscosity with a strong perpendicular magnetic field; here, we examine this scenario using Langevin dynamics simulations of 2D liquids with a binary Yukawa interparticle interaction. The shear viscosity η of 2D liquid dusty plasma is estimated from the simulation data using the Green-Kubo relation, which is the integration of the shear stress autocorrelation function. It is found that, when a perpendicular magnetic field is applied, the shear viscosity of 2D liquid dusty plasma is modified substantially. When the magnetic field is increased, its viscosity increases at low temperatures, while at high temperatures its viscosity diminishes. It is determined that these different variational trends of η arise from the different behaviors of the kinetic and potential parts of the shear stress under external magnetic fields.

  9. Distortion definition and correction in off-axis systems

    Science.gov (United States)

    Da Deppo, Vania; Simioni, Emanuele; Naletto, Giampiero; Cremonese, Gabriele

    2015-09-01

    Off-axis optical configurations are becoming more and more used in a variety of applications, in particular they are the most preferred solution for cameras devoted to Solar System planets and small bodies (i.e. asteroids and comets) study. Off-axis designs, being devoid of central obstruction, are able to guarantee better PSF and MTF performance, and thus higher contrast imaging capabilities with respect to classical on-axis designs. In particular they are suitable for observing extended targets with intrinsic low contrast features, or scenes where a high dynamical signal range is present. Classical distortion theory is able to well describe the performance of the on-axis systems, but it has to be adapted for the off-axis case. A proper way to deal with off-axis distortion definition is thus needed together with dedicated techniques to accurately measure and hence remove the distortion effects present in the acquired images. In this paper, a review of the distortion definition for off-axis systems will be given. In particular the method adopted by the authors to deal with the distortion related issues (definition, measure, removal) in some off-axis instruments will be described in detail.

  10. Model-based therapeutic correction of hypothalamic-pituitary-adrenal axis dysfunction.

    Directory of Open Access Journals (Sweden)

    Amos Ben-Zvi

    2009-01-01

    Full Text Available The hypothalamic-pituitary-adrenal (HPA axis is a major system maintaining body homeostasis by regulating the neuroendocrine and sympathetic nervous systems as well modulating immune function. Recent work has shown that the complex dynamics of this system accommodate several stable steady states, one of which corresponds to the hypocortisol state observed in patients with chronic fatigue syndrome (CFS. At present these dynamics are not formally considered in the development of treatment strategies. Here we use model-based predictive control (MPC methodology to estimate robust treatment courses for displacing the HPA axis from an abnormal hypocortisol steady state back to a healthy cortisol level. This approach was applied to a recent model of HPA axis dynamics incorporating glucocorticoid receptor kinetics. A candidate treatment that displays robust properties in the face of significant biological variability and measurement uncertainty requires that cortisol be further suppressed for a short period until adrenocorticotropic hormone levels exceed 30% of baseline. Treatment may then be discontinued, and the HPA axis will naturally progress to a stable attractor defined by normal hormone levels. Suppression of biologically available cortisol may be achieved through the use of binding proteins such as CBG and certain metabolizing enzymes, thus offering possible avenues for deployment in a clinical setting. Treatment strategies can therefore be designed that maximally exploit system dynamics to provide a robust response to treatment and ensure a positive outcome over a wide range of conditions. Perhaps most importantly, a treatment course involving further reduction in cortisol, even transient, is quite counterintuitive and challenges the conventional strategy of supplementing cortisol levels, an approach based on steady-state reasoning.

  11. From the Bottom-Up: Chemotherapy and Gut-Brain Axis Dysregulation.

    Science.gov (United States)

    Bajic, Juliana E; Johnston, Ian N; Howarth, Gordon S; Hutchinson, Mark R

    2018-01-01

    The central nervous system and gastrointestinal tract form the primary targets of chemotherapy-induced toxicities. Symptoms associated with damage to these regions have been clinically termed chemotherapy-induced cognitive impairment and mucositis. Whilst extensive literature outlines the complex etiology of each pathology, to date neither chemotherapy-induced side-effect has considered the potential impact of one on the pathogenesis of the other disorder. This is surprising considering the close bidirectional relationship shared between each organ; the gut-brain axis. There are complex multiple pathways linking the gut to the brain and vice versa in both normal physiological function and disease. For instance, psychological and social factors influence motility and digestive function, symptom perception, and behaviors associated with illness and pathological outcomes. On the other hand, visceral pain affects central nociception pathways, mood and behavior. Recent interest highlights the influence of functional gut disorders, such as inflammatory bowel diseases and irritable bowel syndrome in the development of central comorbidities. Gut-brain axis dysfunction and microbiota dysbiosis have served as key portals in understanding the potential mechanisms associated with these functional gut disorders and their effects on cognition. In this review we will present the role gut-brain axis dysregulation plays in the chemotherapy setting, highlighting peripheral-to-central immune signaling mechanisms and their contribution to neuroimmunological changes associated with chemotherapy exposure. Here, we hypothesize that dysregulation of the gut-brain axis plays a major role in the intestinal, psychological and neurological complications following chemotherapy. We pay particular attention to evidence surrounding microbiota dysbiosis, the role of intestinal permeability, damage to nerves of the enteric and peripheral nervous systems and vagal and humoral mediated changes.

  12. Fatigue in tension perpendicular to the grain

    DEFF Research Database (Denmark)

    Clorius, Christian Odin; Pedersen, Martin Bo Uhre; Hoffmeyer, Preben

    1999-01-01

    Traditinally fatigue resistance is quantified as number of cycles to failure at a given stress level. A previous study by the authors showed that fatigue in compression parallel to the grain is governed partly by duration of load and partly by an effect of loading, i.e. a combination of a creep...... mechanism and a mechanism connected to damage introduce in the loading sequences. The purpose of the present study is to disentangle the effect of duration of load from the effect of load oscillation in fatigue in tension perpendicular to the grain. Fatigue experiments are made on small specimens...... and on dowel type joints with slotted in steel plates. In series of ten, the small specimens are taken to fatigue failure in uniform tension at square wave shaped load cycles at 0.01 Hz and 0.1 Hz. In order to test the predictive validity of the result from the small tension specimens, fatigue experiments...

  13. Fatigue In Tension Perpendicular to the Grain

    DEFF Research Database (Denmark)

    Clorius, Christian Odin; Pedersen, Martin Uhre; Hoffmeyer, Preben

    2004-01-01

    Traditionally fatigue resistance is quantified as number of cycles to failure at a given stress level. A previous study by the authors showed that fatigue in compression parallel to the grain is governed partly by duration of load and partly by an effect of loading, i.e. a combination of a creep...... mechanism and a mechanism connected to damage introduced in the loading sequences. The purpose of the present study is to disentangle the effect of duration of load from the effect of load oscillation in fatigue in tension perpendicular to the grain. Fatigue experiments are made on small specimens...... and on dowel type joints with slotted in steel plates. In series of ten, the small specimens are taken to fatigue failure in uniform tension at square wave shaped load cycles at 0.01 Hz and 0.1 Hz. In arder to test the predictive validity of the result from the small tension specimens, fatigue experiments...

  14. Electric field scales at quasi-perpendicular shocks

    Directory of Open Access Journals (Sweden)

    S. N. Walker

    2004-07-01

    Full Text Available This paper investigates the short scale structures that are observed in the electric field during crossings of the quasi-perpendicular bow shock using data from the Cluster satellites. These structures exhibit large amplitudes, as high as 70 m Vm-1 and so make a significant contribution to the overall change in potential at the shock front. It is shown that the scale size of these short-lived electric field structures is of the order of a few cpe. The relationships between the scale size and the upstream Mach number and θBn are studied. It is found that the scale size of these structures decreases with increasing plasma β and as θBn→90°. The amplitude of the spikes remains fairly constant with increasing Ma and appears to increase as θBn→90°.

  15. Counterstreaming magnetized plasmas. II. Perpendicular wave propagation

    International Nuclear Information System (INIS)

    Tautz, R.C.; Schlickeiser, R.

    2006-01-01

    The properties of longitudinal and transverse oscillations in magnetized symmetric counterstreaming Maxwellian plasmas with equal thermal velocities for waves propagating perpendicular to the stream direction are investigated on the basis of Maxwell equations and the nonrelativistic Vlasov equation. With the constraint of vanishing particle flux in the stream direction, three distinct dispersion relations are known, which are the ordinary-wave mode, the Bernstein wave mode, and the extraordinary electromagnetic wave mode, where the latter two are only approximations. In this article, all three dispersion relations are evaluated for a counterstreaming Maxwellian distribution function in terms of the hypergeometric function 2 F 2 . The growth rates for the ordinary-wave mode are compared to earlier results by Bornatici and Lee [Phys. Fluids 13, 3007 (1970)], who derived approximate results, whereas in this article the exact dispersion relation is solved numerically. The original results are therefore improved and show differences of up to 21% to the results obtained in this article

  16. Fracture resistance of welded panel specimen with perpendicular crack in tensile

    International Nuclear Information System (INIS)

    Gochev, Todor; Adziev, Todor

    1998-01-01

    Defects caused by natural crack in welded joints of high-strength low-alloy (HSLA) steels are very often. Perpendicular crack in welded joints and its heat treatment after the welding has also an influence on the fracture resistance. The fracture resistance of welded joints by crack in tense panel specimens was investigated by crack mouse opening displesment (CMOD), the parameter of fracture mechanic. Crack propagation was analysed by using a metallographic analysis of fractured specimens after the test. (Author)

  17. Size effect in tension perpendicular to the grain

    DEFF Research Database (Denmark)

    Pedersen, Martin Bo Uhre; Clorius, Christian Odin; Damkilde, Lars

    1999-01-01

    The strength in tension perpendicular to the grain is known to decrease with an increase in the stressed volume. Usually this size effect is explained on a stochastic basis, that is an explanation relying on an increased probability of encountering a strength reducing flaw when the volume...... of the material under stress is increased. This paper presents a small experimental investigation on specimens with well defined structural orientation of the material. The experiments exhibit a larger size effect than expected and furthermore the data and the nature of the failures encountered suggest...... that the size effect can be explained on a deterministic basis. Arguments for such a simple deterministic explanation of size effect is found in finite element modelling using the orthotropic stiffness characteristics in the transverse plane of wood....

  18. Actuator assembly including a single axis of rotation locking member

    Science.gov (United States)

    Quitmeyer, James N.; Benson, Dwayne M.; Geck, Kellan P.

    2009-12-08

    An actuator assembly including an actuator housing assembly and a single axis of rotation locking member fixedly attached to a portion of the actuator housing assembly and an external mounting structure. The single axis of rotation locking member restricting rotational movement of the actuator housing assembly about at least one axis. The single axis of rotation locking member is coupled at a first end to the actuator housing assembly about a Y axis and at a 90.degree. angle to an X and Z axis providing rotation of the actuator housing assembly about the Y axis. The single axis of rotation locking member is coupled at a second end to a mounting structure, and more particularly a mounting pin, about an X axis and at a 90.degree. angle to a Y and Z axis providing rotation of the actuator housing assembly about the X axis. The actuator assembly is thereby restricted from rotation about the Z axis.

  19. Conception and realization of a PV system provided with a sun tracker operating at dual axis

    Directory of Open Access Journals (Sweden)

    Khalil Kassmi

    2016-06-01

    Full Text Available In this paper, we present the conception, the realization and the experimentation of  a photovoltaic (PV system provided with a sun tracker reliable and low cost operating at dual axis. The tracker's role is to orient the PV generator, whose weight may reach 9 Kg, perpendicular to the sun with very good accuracy. This tracking  based on the use of four LDR sensors, which detect the intensity of light scattered by the sun a processing unit, from  command and control (UTCC, which manages all of the sun tracking tasks (the end detection of parcours, regulation of the power supplied by the PV panels (Command MPPT, ... . The results obtained show a significant improvement of the energy produced, compared to conventional PV installations where generators are fixed and oriented south at a  tilt 45°. During a day of operation, improvement could reach 41% and consumption of the tracking does not exceed 0.55% of the energy production produced by the PV generator (an improvement of 5 % compared to existing trackers.

  20. Effect of Relative Marker Movement on the Calculation of the Foot Torsion Axis Using a Combined Cardan Angle and Helical Axis Approach

    Science.gov (United States)

    Graf, Eveline S.; Wright, Ian C.; Stefanyshyn, Darren J.

    2012-01-01

    The two main movements occurring between the forefoot and rearfoot segment of a human foot are flexion at the metatarsophalangeal joints and torsion in the midfoot. The location of the torsion axis within the foot is currently unknown. The purpose of this study was to develop a method based on Cardan angles and the finite helical axis approach to calculate the torsion axis without the effect of flexion. As the finite helical axis method is susceptible to error due to noise with small helical rotations, a minimal amount of rotation was defined in order to accurately determine the torsion axis location. Using simulation, the location of the axis based on data containing noise was compared to the axis location of data without noise with a one-sample t-test and Fisher's combined probability score. When using only data with helical rotation of seven degrees or more, the location of the torsion axis based on the data with noise was within 0.2 mm of the reference location. Therefore, the proposed method allowed an accurate calculation of the foot torsion axis location. PMID:22666303

  1. Effect of Relative Marker Movement on the Calculation of the Foot Torsion Axis Using a Combined Cardan Angle and Helical Axis Approach

    Directory of Open Access Journals (Sweden)

    Eveline S. Graf

    2012-01-01

    Full Text Available The two main movements occurring between the forefoot and rearfoot segment of a human foot are flexion at the metatarsophalangeal joints and torsion in the midfoot. The location of the torsion axis within the foot is currently unknown. The purpose of this study was to develop a method based on Cardan angles and the finite helical axis approach to calculate the torsion axis without the effect of flexion. As the finite helical axis method is susceptible to error due to noise with small helical rotations, a minimal amount of rotation was defined in order to accurately determine the torsion axis location. Using simulation, the location of the axis based on data containing noise was compared to the axis location of data without noise with a one-sample t-test and Fisher's combined probability score. When using only data with helical rotation of seven degrees or more, the location of the torsion axis based on the data with noise was within 0.2 mm of the reference location. Therefore, the proposed method allowed an accurate calculation of the foot torsion axis location.

  2. Quantitative and clinical evaluation of whole CSF-axis RI image

    International Nuclear Information System (INIS)

    Tomono, Yuji; Nose, Tadao; Maki, Yutaka

    1987-01-01

    Whole CSF-axis RI scintigraphy was evaluated in 122 adult patients intending to know not only intracranial CSF flow but also the dynamics of whole CSF axis, particularly of spinal CSF flow. The change of radioactivity in several compartments was studied quantitatively with a dataprocessor on 18 cases with dilated ventricles, and more practically, clinical features and the findings of the films were comparatively studied on all the cases. The results were as follows: (1) Roughly speaking, the findings were classified into two types, i.e. a type with early RI movement to the intracranial CSF space and another with stagnation of radioactivity in spinal space till late stage, even 48 hours after RI injection (spinal stasis). (2) Although majority of the cases with spinal stasis did not show ventricular stasis, a shunt operation was not effective even when ventricular stasis was observed. (3) Spinal stasis tended to increase with aging, and was observed more frequently in cases with possible severe cerebral damage, as severe cerebrovascular disease and severe deterioration of mental activity. (4) The clearance of radioactivity of whole CSF-axis was remarkably delayed. It is considered that the spinal CSF flow is generated by intracranial CSF pulsation and, so, that spinal stasis shows the condition of lowered CSF flow by pulsation due to cerebral parenchymal damages. (author)

  3. Enhanced post-annealing stability of perpendicular Ta/CoFeB/Mg/MgO multilayers by inhibiting Ta diffusion

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xu-Jing; Jiang, Shao-Long; Zhang, Jing-Yan; Liu, Qian-Qian; Liu, Yi-Wei; Zhao, Jian-Cheng [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); Wu, Zheng-Long [Analytical and Testing Center, Beijing Normal University, Beijing 100875 (China); Feng, Chun, E-mail: fengchun@ustb.edu.cn [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); Li, Ming-Hua [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); Yu, Guang-Hua, E-mail: ghyu@mater.ustb.edu.cn [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China)

    2016-03-01

    Graphical abstract: To reveal the underlying mechanism of Mg influence on the enhanced post-annealing stability of perpendicular Ta/CoFeB/Mg/MgO multilayers, the X-ray photoelectron spectroscopy analysis have been performed. It is found that a certain amount of Mg interlayer at the CoFeB/MgO interface could prevent the Ta oxidation to some extent due to the oxygen deficit MgO{sub x} (x < 1), and consequently lower the diffusion motivation of Ta from the bottom layer to the CoFeB/MgO interfaces to some extent during the annealing process. The prevention of Ta diffusion realizes the effective hybridization of Fe and O at the CoFeB/MgO interface and maintains interfacial magnetic anisotropy (K{sub CoFeB/MgO}). As a result, the perpendicular magnetic anisotropy at high annealing temperatures was maintained. - Highlights: • High annealing stability of perpendicular Ta/CoFeB/Mg/MgO multilayers was realized. • X-ray photoelectron spectroscopy analysis has been performed to explore the reasons. • The prevention of Ta diffusion was realized by introducing Mg at the CoFeB/MgO interface. - Abstracts: To reveal the underlying mechanism of Mg influence on the enhanced post-annealing stability of perpendicular Ta/CoFeB/Mg/MgO multilayers, the X-ray photoelectron spectroscopy analysis has been performed. It is found that a certain amount of Mg interlayer at the CoFeB/MgO interface could prevent the Ta oxidation, and consequently lower the diffusion motivation of Ta from the bottom layer to the CoFeB/MgO interfaces to some extent in the annealing process. The prevention of Ta diffusion realizes the effective hybridization of Fe and O at the CoFeB/MgO interface and maintains interfacial magnetic anisotropy (KCoFeB/MgO). As a result, the perpendicular magnetic anisotropy at high annealing temperatures is maintained.

  4. Enhanced post-annealing stability of perpendicular Ta/CoFeB/Mg/MgO multilayers by inhibiting Ta diffusion

    International Nuclear Information System (INIS)

    Li, Xu-Jing; Jiang, Shao-Long; Zhang, Jing-Yan; Liu, Qian-Qian; Liu, Yi-Wei; Zhao, Jian-Cheng; Wu, Zheng-Long; Feng, Chun; Li, Ming-Hua; Yu, Guang-Hua

    2016-01-01

    Graphical abstract: To reveal the underlying mechanism of Mg influence on the enhanced post-annealing stability of perpendicular Ta/CoFeB/Mg/MgO multilayers, the X-ray photoelectron spectroscopy analysis have been performed. It is found that a certain amount of Mg interlayer at the CoFeB/MgO interface could prevent the Ta oxidation to some extent due to the oxygen deficit MgO_x (x < 1), and consequently lower the diffusion motivation of Ta from the bottom layer to the CoFeB/MgO interfaces to some extent during the annealing process. The prevention of Ta diffusion realizes the effective hybridization of Fe and O at the CoFeB/MgO interface and maintains interfacial magnetic anisotropy (K_C_o_F_e_B_/_M_g_O). As a result, the perpendicular magnetic anisotropy at high annealing temperatures was maintained. - Highlights: • High annealing stability of perpendicular Ta/CoFeB/Mg/MgO multilayers was realized. • X-ray photoelectron spectroscopy analysis has been performed to explore the reasons. • The prevention of Ta diffusion was realized by introducing Mg at the CoFeB/MgO interface. - Abstracts: To reveal the underlying mechanism of Mg influence on the enhanced post-annealing stability of perpendicular Ta/CoFeB/Mg/MgO multilayers, the X-ray photoelectron spectroscopy analysis has been performed. It is found that a certain amount of Mg interlayer at the CoFeB/MgO interface could prevent the Ta oxidation, and consequently lower the diffusion motivation of Ta from the bottom layer to the CoFeB/MgO interfaces to some extent in the annealing process. The prevention of Ta diffusion realizes the effective hybridization of Fe and O at the CoFeB/MgO interface and maintains interfacial magnetic anisotropy (KCoFeB/MgO). As a result, the perpendicular magnetic anisotropy at high annealing temperatures is maintained

  5. Bmp suppression in mangrove killifish embryos causes a split in the body axis.

    Directory of Open Access Journals (Sweden)

    Sulayman Mourabit

    Full Text Available Bone morphogenetic proteins (Bmp are major players in the formation of the vertebrate body plan due to their crucial role in patterning of the dorsal-ventral (DV axis. Despite the highly conserved nature of Bmp signalling in vertebrates, the consequences of changing this pathway can be species-specific. Here, we report that Bmp plays an important role in epiboly, yolk syncytial layer (YSL movements, and anterior-posterior (AP axis formation in embryos of the self-fertilizing mangrove killifish, Kryptolebias marmoratus. Stage and dose specific exposures of embryos to the Bmp inhibitor dorsomorphin (DM produced three distinctive morphologies, with the most extreme condition creating the splitbody phenotype, characterised by an extremely short AP axis where the neural tube, somites, and notochord were bilaterally split. In addition, parts of caudal neural tissues were separated from the main body and formed cell islands in the posterior region of the embryo. This splitbody phenotype, which has not been reported in other animals, shows that modification of Bmp may lead to significantly different consequences during development in other vertebrate species.

  6. Hypothalamic-pituitary-adrenal axis, childhood adversity and adolescent nonsuicidal self-injury.

    Science.gov (United States)

    Reichl, Corinna; Heyer, Anne; Brunner, Romuald; Parzer, Peter; Völker, Julia Madeleine; Resch, Franz; Kaess, Michael

    2016-12-01

    Whereas childhood adversity (CA) and the hypothalamus-pituitary-adrenal (HPA) axis have been suggested to play a major role in the etiology of non-suicidal self-injury (NSSI), no study has thus far investigated both its associations and interactions with adolescent NSSI. We investigated CA (antipathy, neglect, physical, psychological, and sexual abuse) and indices of HPA axis activity (salivary and hair cortisol) in a clinical sample of 26 adolescents engaging in NSSI and 26 age- and gender-matched healthy controls (HC). We used standardized interviews for the assessment of CA (CECA), NSSI (SITBI-G), and axis I diagnoses (MINI-KID). Salivary cortisol sampling was surveyed using a monitoring system and instructed via telephone calls. Adolescents engaging in NSSI exhibited significantly higher cortisol awakening responses compared to HC. No differences were found with respect to the diurnal slope or hair cortisol. In the presence of CA, healthy adolescents showed flatted diurnal cortisol slopes while those engaging in NSSI exhibited significantly steeper ones. Our findings indicate that adolescents engaging in NSSI may exhibit a stronger cortisol awakening response, potentially in expectation of strain. However, elevated cortisol levels may not be maintained throughout the day, especially among adolescents with a history of CA. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Probing structure-property relationships in perpendicularly magnetized Fe/Cu(001) using MXLD and XPD

    Energy Technology Data Exchange (ETDEWEB)

    Cummins, T.R.; Waddill, G.D. [Univ. of Missouri, Rolla, MO (United States); Goodman, K.W. [Lawrence Berkeley National Lab., CA (United States)] [and others

    1997-04-01

    Magnetic X-ray Linear Dichroism (MXLD) in Photoelectron Spectroscopy and X-Ray Photoelectron Diffraction (XPD) of the Fe 3p core level have been used to probe the magnetic structure-property relationships of perpendicularly magnetized Fe/Cu(001), in an element-specific fashion. A strong MEXLD effect was observed in the high resolution photoelectron spectroscopy of the Fe 3p at {open_quotes}normal{close_quotes} emission and was used to follow the loss of perpendicular ferromagnetic ordering as the temperature was raised toward room temperature. In parallel with this, {open_quotes}Forward Focussing{close_quotes} in XPD was used as a direct measure of geometric structure in the overlayer. These results and the implications of their correlation will be discussed. Additionally, an investigation of the effect of Mn doping of the Fe/Cu(001) will be described. These measurements were performed at the Spectromicroscopy Facility (Beamline 7.0.1) of the Advanced Light Source.

  8. Divergences between clinical and research methods for assessing personality disorders: implications for research and the evolution of axis II.

    Science.gov (United States)

    Westen, D

    1997-07-01

    The purpose of this study was to examine the extent to which instruments for assessing axis II diverge from clinical diagnostic processes. Subjects in the first study were 52 clinicians with experience in assessment and treatment of patients with personality disorders, who were surveyed about the methods they use in clinical practice to make diagnoses and other aspects of the diagnostic process. A second study replicated the major findings with a random national sample of 1,901 experienced psychiatrists and psychologists. Whereas current instruments rely primarily on direct questions derived from DSM-IV, clinicians of every theoretical persuasion found direct questions useful for assessing axis I disorders but only marginally so for axis II. They made axis II diagnoses, instead, by listening to patients describe interpersonal interactions and observing their behavior with the interviewer. In contrast to findings with current research instruments, most patients with personality disorders in clinical practice receive only one axis II diagnosis, and if they receive more than one, one is considered primary. Clinicians reported treating a substantial number of patients for enduring personality patterns that current axis II instruments do not assess, many of which meet neither axis I nor axis II criteria, notably problems with relatedness, work, self-esteem, and chronic subclinical depressive traits. Measurements of axis II were constructed by using a model derived from axis I instruments that diverges from clinical diagnostic procedures in a way that may be problematic for the assessment of personality disorders and the development of a more clinically and empirically sound taxonomy.

  9. Early-onset Major Depressive Disorder in men is associated with childlessness.

    Science.gov (United States)

    Yates, William R; Meller, William H; Lund, Brian C; Thurber, Steve; Grambsch, Patricia L

    2010-07-01

    The self-reported number of children was compared for men and women from the National Epidemiologic Survey of Alcoholism and Related Conditions Survey (NESARC). Subjects with a diagnosis of major depressive disorder or bipolar disorder were compared to those without an axis I disorder. The effect of age, gender, marriage and diagnostic status on number of children was completed using multivariate analyses. Men with a history of major depressive disorder but not bipolar disorder reported higher rates of childlessness and lower mean number of children. This reduced number of children was related to an early age of onset of MDD. Thirty percent of men with an age of onset of MDD before 22 were childless compared to only 18.9% of men without an axis I disorder (Odds ratio=1.82, 95% CI=1.45-2.27). No effect of mood disorder on number of children was found in women with major depression or bipolar disorder. This study suggests that an early age of onset of major depressive disorder contributes to childlessness in men.

  10. Observation of the domain structure in Fe-Au superlattices with perpendicular anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Zoladz, M. E-mail: zoladz@uci.agh.edu.pl; Slezak, T.; Wilgocka-Slezak, D.; Spiridis, N.; Korecki, J.; Stobiecki, T. E-mail: stobieck@uci.agh.edu.pl; Roell, K

    2004-05-01

    Polar Kerr Microscopy was used to visualize characteristic transitions and external magnetic field driven domain structure evolution in a perpendicularly magnetized Fe-Au AF/FM double multilayer structure. Real time imaging performed in the external magnetic field allowed for identification of all sublayers magnetization reversal in accordance with measured PMOKE magnetization curve, showing strong dependence of transition character on the interlayer coupling type and adjacent sublayers magnetization orientation.

  11. Observation of the domain structure in Fe-Au superlattices with perpendicular anisotropy

    International Nuclear Information System (INIS)

    Zoladz, M.; Slezak, T.; Wilgocka-Slezak, D.; Spiridis, N.; Korecki, J.; Stobiecki, T.; Roell, K.

    2004-01-01

    Polar Kerr Microscopy was used to visualize characteristic transitions and external magnetic field driven domain structure evolution in a perpendicularly magnetized Fe-Au AF/FM double multilayer structure. Real time imaging performed in the external magnetic field allowed for identification of all sublayers magnetization reversal in accordance with measured PMOKE magnetization curve, showing strong dependence of transition character on the interlayer coupling type and adjacent sublayers magnetization orientation

  12. On the left perpendicular category of the modules of finite projective dimension

    OpenAIRE

    Araya, Tokuji; Iima, Kei-ichiro; Takahashi, Ryo

    2010-01-01

    In this paper, we characterize several properties of commutative notherian local rings in terms of the left perpendicular category of the category of finitely generated modules of finite projective dimension. As an application we prove that a local ring is regular if (and only if) there exists a strong test module for projectivity having finite projective dimension. We also obtain corresponding results with respect to a semidualizing module.

  13. Superparamagnetic perpendicular magnetic tunnel junctions for true random number generators

    Science.gov (United States)

    Parks, Bradley; Bapna, Mukund; Igbokwe, Julianne; Almasi, Hamid; Wang, Weigang; Majetich, Sara A.

    2018-05-01

    Superparamagnetic perpendicular magnetic tunnel junctions are fabricated and analyzed for use in random number generators. Time-resolved resistance measurements are used as streams of bits in statistical tests for randomness. Voltage control of the thermal stability enables tuning the average speed of random bit generation up to 70 kHz in a 60 nm diameter device. In its most efficient operating mode, the device generates random bits at an energy cost of 600 fJ/bit. A narrow range of magnetic field tunes the probability of a given state from 0 to 1, offering a means of probabilistic computing.

  14. Torsion testing of bed joints

    DEFF Research Database (Denmark)

    Hansen, Klavs Feilberg; Pedersen, Carsten Mørk

    2008-01-01

    This paper describes a simple test method for determining the torsion strength of a single bed joint between two bricks and presents results from testing using this test method. The setup for the torsion test is well defined, require minimal preparation of the test specimen and the test can...... be carried out directly in a normal testing machine. The torsion strength is believed to be the most important parameter in out-of-plane resistance of masonry walls subjected to bending about an axis perpendicular to the bed joints. The paper also contains a few test results from bending of small walls about...... an axis perpendicular to the bed joints, which indicate the close connection between these results and results from torsion tests. These characteristics make the torsion strength well suited to act as substitute parameter for the bending strength of masonry about an axis perpendicular to the bed joints....

  15. Size dependence of spin-torque induced magnetic switching in CoFeB-based perpendicular magnetization tunnel junctions (invited)

    Science.gov (United States)

    Sun, J. Z.; Trouilloud, P. L.; Gajek, M. J.; Nowak, J.; Robertazzi, R. P.; Hu, G.; Abraham, D. W.; Gaidis, M. C.; Brown, S. L.; O'Sullivan, E. J.; Gallagher, W. J.; Worledge, D. C.

    2012-04-01

    CoFeB-based magnetic tunnel junctions with perpendicular magnetic anisotropy are used as a model system for studies of size dependence in spin-torque-induced magnetic switching. For integrated solid-state memory applications, it is important to understand the magnetic and electrical characteristics of these magnetic tunnel junctions as they scale with tunnel junction size. Size-dependent magnetic anisotropy energy, switching voltage, apparent damping, and anisotropy field are systematically compared for devices with different materials and fabrication treatments. Results reveal the presence of sub-volume thermal fluctuation and reversal, with a characteristic length-scale of the order of approximately 40 nm, depending on the strength of the perpendicular magnetic anisotropy and exchange stiffness. To have the best spin-torque switching efficiency and best stability against thermal activation, it is desirable to optimize the perpendicular anisotropy strength with the junction size for intended use. It also is important to ensure strong exchange-stiffness across the magnetic thin film. These combine to give an exchange length that is comparable or larger than the lateral device size for efficient spin-torque switching.

  16. Manipulation of perpendicular magnetic anisotropy of single Fe atom adsorbed graphene via MgO(1 1 1) substrate

    Science.gov (United States)

    Fu, Mingming; Tang, Weiqing; Wu, Yaping; Ke, Congming; Guo, Fei; Zhang, Chunmiao; Yang, Weihuang; Wu, Zhiming; Kang, Junyong

    2018-05-01

    Perpendicular magnetic anisotropy is significantly important for realizing a long-term retention of information for spintronics devices. Inspired by 2D graphene with its high charge carrier mobility and long spin diffusion length, we report a first-principles design framework on perpendicular magnetic anisotropy engineering of a Fe atom adsorbed graphene by employing a O-terminated MgO (1 1 1) substrate. Determined by the adsorption sites of the Fe atom, a tunable magnetic anisotropy is realized in Fe/graphene/MgO (1 1 1) structure, with the magnetic anisotropy energy of  ‑0.48 meV and 0.23 meV, respectively, corresponding to the in-plane and out of plane easy magnetizations. Total density of states suggest a half-metallicity with a 100% spin polarization in the system. Decomposed densities of Fe-3d states reveal the orbital contributions to the magnetic anisotropy for different Fe adsorption sites. Bonding interaction and charge redistribution regulated by MgO substrate are found responsible for the novel perpendicular magnetic anisotropy engineering in the system. The effective manipulation of perpendicular magnetic anisotropy in present work offers some references for the design and construction of 2D spintronics devices.

  17. Dysregulation of the HPA axis as a core pathophysiology mediating co-morbid depression in neurodegenerative diseases

    Directory of Open Access Journals (Sweden)

    Xin eDu

    2015-03-01

    Full Text Available There is increasing evidence of prodromal manifestation of neuropsychiatric symptoms in a variety of neurodegenerative diseases such as Parkinson’s disease and Huntington’s disease. These affective symptoms may be observed many years before the core diagnostic symptoms of the neurological condition. It is becoming more apparent that depression is a significant modifying factor of the trajectory of disease progression, and even treatment outcomes. It is therefore crucial that we understand the potential pathophysiologies related to the primary condition, which could contribute to the development of depression. The hypothalamic-pituitary-adrenal (HPA axis is a key neuroendocrine signaling system involved in physiological homeostasis and stress response. Disturbances of this system lead to severe hormonal imbalances, and the majority of such patients also present with behavioural deficits and/or mood disorders. Dysregulation of the HPA axis is also strongly implicated in the pathology of major depressive disorder. Consistent with this, anti-depressant drugs such as the selective serotonin reuptake inhibitors (SSRI have been shown to alter HPA axis activity. In this review, we will summarize the current state of knowledge regarding HPA axis pathology in Alzheimer’s, Parkinson’s and Huntington’s diseases, differentiating between prodromal and later stages of disease progression where possible. Both clinical and preclinical evidence will be examined, but we highlight animal model studies as being particularly useful for uncovering novel mechanisms of pathology related to co-morbid mood disorders. Finally, we purpose utilizing the pre-clinical evidence to better inform prospective, intervention studies.

  18. An experimentally validated fatigue model for wood subjected to tension perpendicular to the grain

    DEFF Research Database (Denmark)

    Clorius, Christian Odin; Pedersen, Martin Uhre; Hoffmeyer, Preben

    2009-01-01

    This study presents an experimental investigation of fatigue in wood subjected to tension perpendicular to the grain. The study has been designed with special reference to the influence of the frequency of loading. The investigation reveals an interaction between number of load oscillations and a...... a good basis....

  19. Experimental Investigation on Embedding Strength Perpendicular to Grain of Parallel Strand Bamboo

    Directory of Open Access Journals (Sweden)

    Junwen Zhou

    2018-01-01

    Full Text Available Parallel strand bamboo (PSB is a latest construction material; to know more about mechanical properties of PSB, 5 groups of specimens with difference only in bolt diameter were designed to study the impact of the fastener diameter on embedding strength perpendicular to grain of PSB. Based on the tested result, the feasibility for PSB of the theoretical equation in the American code and European code on embedding strength predication was assessed. A controlled displacement was used to load till specimen failure, the stress-displacement curve of all specimens was obtained in terms of the tested results, and the yielding tested strength based on 5% bolt diameter offset proposed by the American code was found. The tested results showed that the yielding strength perpendicular to grain of PSB was stable, the variable coefficient was between 5.88% and 13.34%, and the average yielding strength values were 80.84 MPa, 77.40 MPa, 76.52 MPa, 74.20 MPa, and 67.01 MPa, respectively, which decreased with the increase of bolt diameter, and the average yielding strength values are larger than the calculated results using theoretical formula. Therefore, the theoretical equation on embedding yielding strength of wood in the American code and European code applies to PSB.

  20. Magnetic properties of laser deposited films of Y-Ba-Cu-O

    Energy Technology Data Exchange (ETDEWEB)

    McGuire, T.R.; Dimos, D.; Gupta, A.; Koren, G.; Laibowitz, R.B. (IBM Research Division, T. J. Watson Research Center, P. O. Box 218, Yorktown Heights, New York 10598 (USA))

    1990-05-01

    Films of YBa{sub 2}Cu{sub 3}O{sub 7{minus}{ital x}} prepared by laser ablation deposition show epitaxial growth on (100) SrTiO{sub 3} substrates with the {ital c} axis perpendicular to the plane of the film. With the magnetic field ({ital H}) parallel to the {ital c} axis, critical currents of up to 40 MA/cm{sup 2} from magnetization measurements are obtained. With {ital H} perpendicular to the {ital c} axis, various magnetization measurements with field cooling in 40 kOe indicated strong pinning effects with a calculated critical current density significantly higher than that observed in the parallel field configuration.

  1. In-plane current-driven spin-orbit torque switching in perpendicularly magnetized films with enhanced thermal tolerance

    International Nuclear Information System (INIS)

    Wu, Di; Yu, Guoqiang; Shao, Qiming; Li, Xiang; Wong, Kin L.; Wang, Kang L.; Wu, Hao; Han, Xiufeng; Zhang, Zongzhi; Khalili Amiri, Pedram

    2016-01-01

    We study spin-orbit-torque (SOT)-driven magnetization switching in perpendicularly magnetized Ta/Mo/Co_4_0Fe_4_0B_2_0 (CoFeB)/MgO films. The thermal tolerance of the perpendicular magnetic anisotropy (PMA) is enhanced, and the films sustain the PMA at annealing temperatures of up to 430 °C, due to the ultra-thin Mo layer inserted between the Ta and CoFeB layers. More importantly, the Mo insertion layer also allows for the transmission of the spin current generated in the Ta layer due to spin Hall effect, which generates a damping-like SOT and is able to switch the perpendicular magnetization. When the Ta layer is replaced by a Pt layer, i.e., in a Pt/Mo/CoFeB/MgO multilayer, the direction of the SOT-induced damping-like effective field becomes opposite because of the opposite sign of spin Hall angle in Pt, which indicates that the SOT-driven switching is dominated by the spin current generated in the Ta or Pt layer rather than the Mo layer. Quantitative characterization through harmonic measurements reveals that the large SOT effective field is preserved for high annealing temperatures. This work provides a route to applying SOT in devices requiring high temperature processing steps during the back-end-of-line processes.

  2. Non-stationarity of the quasi-perpendicular bow shock: comparison between Cluster observations and simulations

    Directory of Open Access Journals (Sweden)

    H. Comişel

    2011-02-01

    Full Text Available We have performed full particle electromagnetic simulations of a quasi-perpendicular shock. The shock parameters have been chosen to be appropriate for the quasi-perpendicular Earth's bow shock observed by Cluster on 24 January 2001 (Lobzin et al., 2007. We have performed two simulations with different ion to electron mass ratio: run 1 with mi/me=1840 and run 2 with mi/me=100. In run 1 the growth rate of the modified two-stream instability (MTSI is large enough to get excited during the reflection and upstream gyration of part of the incident solar wind ions. The waves due to the MTSI are on the whistler mode branch and have downstream directed phase velocities in the shock frame. The Poynting flux (and wave group velocity far upstream in the foot is also directed in the downstream direction. However, in the density and magnetic field compression region of the overshoot the waves are refracted and the Poynting flux in the shock frame is directed upstream. The MTSI is suppressed in the low mass ratio run 2. The low mass ratio run shows more clearly the non-stationarity of the shock with a larger time scale of the order of an inverse ion gyrofrequency (Ωci: the magnetic field profile flattens and steepens with a period of ~1.5Ωci−1. This non-stationarity is different from reformation seen in previous simulations of perpendicular or quasi-perpendicular shocks. Beginning with a sharp shock ramp the large electric field in the normal direction leads to high reflection rate of solar wind protons. As they propagate upstream, the ion bulk velocity decreases and the magnetic field increases in the foot, which results in a flattening of the magnetic field profile and in a decrease of the normal electric field. Subsequently the reflection rate decreases and the whole shock profile steepens again. Superimposed on this 'breathing' behavior are in the realistic mass ratio case the waves due to the MTSI. The simulations lead us to a re-interpretation of

  3. Heating of charged particles by electrostatic wave propagating perpendicularly to uniform magnetic field

    International Nuclear Information System (INIS)

    Niu, Keishiro; Shimojo, Takashi.

    1978-02-01

    Increase in kinetic energy of a charged particle, affected by an electrostatic wave propagating perpendicularly to a uniform magnetic field, is obtained for both the initial and later stages. Detrapping time of the particle from the potential dent of the electrostatic wave and energy increase during trapping of the particle is analytically derived. Numerical simulations are carried out to support theoretical results. (auth.)

  4. Colossal X-Ray-Induced Persistent Photoconductivity in Current-Perpendicular-to-Plane Ferroelectric/Semiconductor Junctions

    KAUST Repository

    Hu, Weijin; Paudel, Tula R.; Lopatin, Sergei; Wang, Zhihong; Ma, He; Wu, Kewei; Bera, Ashok; Yuan, Guoliang; Gruverman, Alexei; Tsymbal, Evgeny Y.; Wu, Tao

    2017-01-01

    . So far, PPC has been observed in bulk materials and thin-film structures, where the current flows in the plane, limiting the magnitude of the effect. Here using epitaxial Nb:SrTiO3/Sm0.1Bi0.9FeO3/Pt junctions with a current-perpendicular-to-plane

  5. Suicidal behavior on Axis VI: clinical data supporting a sixth Axis for DSM-V.

    Science.gov (United States)

    Van Orden, Kimberly A; Witte, Tracy K; Holm-Denoma, Jill; Gordon, Kathryn H; Joiner, Thomas E

    2011-01-01

    Oquendo and colleagues (Oquendo, Baca-García, Mann, & Giner, 2008; Oquendo & Currier, 2009) recommend that DSM-V emphasize suicide risk assessment on a sixth axis, thereby increasing regularity of suicide risk assessments. We propose that evidence of nonredundancy with Axis V - Global Assessment of Functioning (GAF) is one piece of data that can serve as a starting point for a line of research establishing incremental predictive utility for a separate suicide risk assessment in the DSM framework. A standardized suicide risk assessment protocol, measures of depressive, anxious, and eating disordered symptomatology, as well as an index of comorbidity were administered to a sample of 412 adult outpatients. Our data indicate that data from standardized suicide risk assessments are associated with indices of symptomatology severity as well as comorbidity, controlling for GAF. These results support the nonredundancy of the assessments and suggest the utility of longitudinal investigations of the predictive utility of a sixth DSM axis in the assessment of suicide risk.

  6. Electrons of high perpendicular energy in the low-density regime of Tokamaks

    International Nuclear Information System (INIS)

    Bornatici, M.; Engelmann, F.

    1978-01-01

    Effects due to instabilities excited in the low-density regime of tokamaks by runaway electrons via the cyclotron resonance ω+Ω=kV along with the formation of a positive slope in the runaway distribution are considered. Conditions for the production of electrons of high perpendicular energy and their trapping in toroidal field ripples, leading to liner damage, are discussed and found to be rather stringent. Fairly good agreement with the experiments is found

  7. Ethyl 2-(2-oxo-3-phenyl-1,2-dihydroquinoxalin-1-ylacetate

    Directory of Open Access Journals (Sweden)

    Nadeem Abad

    2018-04-01

    Full Text Available In the title compound, C18H16N2O3, the dihydroquinoxaline moiety is planar (r.m.s. deviation = 0.0115 Å and the majority of the ester substituent is nearly perpendicular to its mean plane. In the crystal, the molecules form oblique stacks along the b-axis direction through slipped π–π stacking interactions between adjacent dihydroquinoxaline units. C—H...O hydrogen bonds between the ester substituents on adjacent stacks form thick layers with the stacks on their outside surfaces. These layers extend along the c-axis direction and are coupled through C—H...π(ring interactions. The structure was refined as a two-component twin.

  8. Coercivity enhancements of Nd–Fe–B sintered magnets by diffusing DyHx along different axes

    International Nuclear Information System (INIS)

    Ma, Tianyu; Wang, Xuejiao; Liu, Xiaolian; Wu, Chen; Yan, Mi

    2015-01-01

    Diffusing heavy rare earth elements along the grain boundaries (GBs) for Nd 2 Fe 14 B-type sintered magnets serves as an effective method to enhance coercivity and to minimize remanence loss simultaneously. Considering the texture anisotropy of Nd-rich GB phases, the coercivity incremental difference by diffusing DyH x fine powders along or perpendicular to the  <0 0 1 >  easy axis (c-axis) has been investigated. The coercivity increases more rapidly to 20.61 kOe (5.76 kOe higher than that of the as-sintered state) when diffusing along the c-axis than that diffusing perpendicular to c-axis (18.85 kOe, 4.00 kOe higher than the as-sintered state). Microstructural investigation reveals that Dy diffuses more easily towards the magnet inner part when treating along the c-axis than that for the perpendicular case due to the anisotropic distribution of the Nd-rich phase. This is verified by a higher Dy content at equivalent diffusing depth and a much deeper final diffusion distance. The local Dy-containing fractions with a stronger anisotropy field are richer for the magnet treated along the c-axis, leading to the much rapider coercivity enhancement. This work reveals that diffusion heavy rare earth along the c-axis is more effective to enhance coercivity for aligned Nd–Fe–B sintered magnets. (paper)

  9. Perpendicular magnetic tunnel junction with tunneling magnetoresistance ratio of 64% using MgO (100) barrier layer prepared at room temperature

    International Nuclear Information System (INIS)

    Ohmori, Hideto; Hatori, Tomoya; Nakagawa, Shigeki

    2008-01-01

    MgO (100) textured films can be prepared by reactive facing targets sputtering at room temperature without postdeposition annealing process when they were deposited on (100) oriented Fe buffer layers. This method allows fabrication of perpendicular magnetic tunnel junction (p-MTJ) with MgO (100) tunneling barrier layer and rare-earth transition metal (RE-TM) alloy thin films as perpendicularly magnetized free and pinned layers. The 3-nm-thick MgO tunneling barrier layer in p-MTJ multilayer prepared on glass substrate revealed (100) crystalline orientation. Extraordinary Hall effect measurement clarified that the perpendicular magnetic components of 3-nm-thick Fe buffer layers on the two ends of MgO tunneling barrier layer were increased by exchange coupling with RE-TM alloy layers. The RA of 35 kΩ μm 2 and tunneling magnetoresistance ratio of 64% was observed in the multilayered p-MTJ element by current-in-plane-tunneling

  10. Perpendicular serial maxillary distraction osteogenesis in cleft lip and palate patients.

    Science.gov (United States)

    Ylikontiola, Leena P; Sándor, George K; Harila, Virpi

    2015-01-01

    Cleft lip and palate patients often have a retruded maxilla with a severely narrowed deficient maxillary arch. This report aims to describe the management of severe maxillary retrusion and constriction in cleft lip and palate patients using distraction osteogenesis applied in serial sequence in two directions perpendicular to each other. Two adult male cleft lip and palate patients were treated with maxillary distraction osteogenesis in two stages. In the first stage, surgically assisted rapid palatal expansion with a tooth-borne device was performed to significantly expand the maxillary arch in the transverse dimension. After the teeth were orthodontically aligned, the horizontal distraction of the maxilla was made by two internal maxillary distraction devices. In the first patient, the maxilla was initially widened by 11 mm and then distracted forward by 20 mm. Despite the breakage of the shaft of one of the two distractors at the end of distraction, a satisfactory occlusion was found at the time of distractor device removal. The maxillary position has remained stable through 8 years of follow-up. In the second patient, the palate was widened by 14 mm and the maxilla was distracted forward by 22 mm. The maxillary position has remained stable through 3 years of follow-up. Sequential serial distraction of maxilla in two planes perpendicular to each other is a safe and stable approach for the treatment of cleft lip and palate patients with severe transverse and anteroposterior discrepancies.

  11. c-axis ac susceptibility in high-Tc superconductors

    International Nuclear Information System (INIS)

    Waldmann, O.; Lichtschlag, G.; Talalaevskii, A.; Kleiner, R.; Mueller, P.; Steinmeyer, F.; Gerhaeuser, W.

    1996-01-01

    We have investigated the angle and magnetic field dependence of the ac susceptibility in Bi 2 Sr 2 CaCu 2 O 8 and YBa 2 Cu 3 O 7 single crystals at low external fields. The ac field was applied perpendicular to the CuO 2 planes. The first and third harmonics of the ac susceptibility exhibit remarkably sharp features when the dc field component perpendicular to the CuO 2 planes passes a threshold field H th . H th is strongly temperature dependent, but is independent of the parallel field component. We propose a simple model which excellently explains the data. Within this model the peak structures are related to the irreversibility line. We discuss the implications of the model for the interpretation of the ac susceptibility. copyright 1996 The American Physical Society

  12. Heating efficiency of high-power perpendicular neutral-beam injection in PDX

    International Nuclear Information System (INIS)

    Hawryluk, R.J.; Arunasalam, V.; Bell, M.

    1982-03-01

    The heating efficiency of high power (up to 7.2 MW) near-perpendicular neutral beam injection in the PDX tokamak is comparable to that of tangential injection in PLT. Collisionless plasmas with central ion temperatures up to 6.5 keV and central electron temperatures greater than 2.5 keV have been obtained. The plasma pressure, including the contribution from the beam particles, increases with increasing beam power and does not appear to saturate, although the parametric dependence of the energy confinement time is different from that observed in ohmic discharges

  13. Time-dependent perpendicular fluctuations in the driven lattice Lorentz gas

    Science.gov (United States)

    Leitmann, Sebastian; Schwab, Thomas; Franosch, Thomas

    2018-02-01

    We present results for the fluctuations of the displacement of a tracer particle on a planar lattice pulled by a step force in the presence of impenetrable, immobile obstacles. The fluctuations perpendicular to the applied force are evaluated exactly in first order of the obstacle density for arbitrarily strong pulling and all times. The complex time-dependent behavior is analyzed in terms of the diffusion coefficient, local exponent, and the non-Skellam parameter, which quantifies deviations from the dynamics on the lattice in the absence of obstacles. The non-Skellam parameter along the force is analyzed in terms of an asymptotic model and reveals a power-law growth for intermediate times.

  14. Ground state energy of a polaron in a superlattice

    International Nuclear Information System (INIS)

    Mensah, S.Y.; Allotey, F.K.A.; Nkrumah, G.; Mensah, N.G.

    2000-10-01

    The ground state energy of a polaron in a superlattice was calculated using the double-time Green functions. The effective mass of the polaron along the planes perpendicular to the superlattice axis was also calculated. The dependence of the ground state energy and the effective mass along the planes perpendicular to the superlattice axis on the electron-phonon coupling constant α and on the superlattice parameters (i.e. the superlattice period d and the bandwidth Δ) were studied. It was observed that if an infinite square well potential is assumed, the ground state energy of the polaron decreases (i.e. becomes more negative) with increasing α and d, but increases with increasing Δ. For small values of α, the polaron ground state energy varies slowly with Δ, becoming approximately constant for large Δ. The effective mass along the planes perpendicular to the superlattice axis was found to be approximately equal to the mass of an electron for all typical values of α, d and Δ. (author)

  15. Effective shunt impedance comparison between s-band standing wave accelerators with on-axis and off-axis couplers

    International Nuclear Information System (INIS)

    Schriber, S.O.; Funk, L.W.; Hutcheon, R.M.

    1976-01-01

    The effective shunt impedances of a side-coupled S-band standing wave accelerating structure and a structure employing on-axis couplers have been compared by measuring the energy of accelerated electrons. Criteria for choosing an on-axis coupled structure compared to side-coupled and ''disk and washer'' accelerating structures are given. (author)

  16. Scale breaking effects in the quark-parton model for large P perpendicular phenomena

    International Nuclear Information System (INIS)

    Baier, R.; Petersson, B.

    1977-01-01

    We discuss how the scaling violations suggested by an asymptotically free parton model, i.e., the Q 2 -dependence of the transverse momentum of partons within hadrons may affect the parton model description of large p perpendicular phenomena. We show that such a mechanism can provide an explanation for the magnitude of the opposite side correlations and their dependence on the trigger momentum. (author)

  17. Wave packet revivals in a graphene quantum dot in a perpendicular magnetic field

    International Nuclear Information System (INIS)

    Torres, J. J.; Romera, E.

    2010-01-01

    We study the time evolution of localized wave packets in graphene quantum dots in a perpendicular magnetic field, focusing on the quasiclassical and revival periodicities, for different values of the magnetic field intensities in a theoretical framework. We have considered contributions of the two inequivalent points in the Brillouin zone. The revival time has been found as an observable that shows the break valley degeneracy.

  18. Perpendicular Magnetic Anisotropy in FePt Patterned Media Employing a CrV Seed Layer

    Directory of Open Access Journals (Sweden)

    Chun Dong

    2011-01-01

    Full Text Available Abstract A thin FePt film was deposited onto a CrV seed layer at 400°C and showed a high coercivity (~3,400 Oe and high magnetization (900–1,000 emu/cm3 characteristic of L10 phase. However, the magnetic properties of patterned media fabricated from the film stack were degraded due to the Ar-ion bombardment. We employed a deposition-last process, in which FePt film deposited at room temperature underwent lift-off and post-annealing processes, to avoid the exposure of FePt to Ar plasma. A patterned medium with 100-nm nano-columns showed an out-of-plane coercivity fivefold larger than its in-plane counterpart and a remanent magnetization comparable to saturation magnetization in the out-of-plane direction, indicating a high perpendicular anisotropy. These results demonstrate the high perpendicular anisotropy in FePt patterned media using a Cr-based compound seed layer for the first time and suggest that ultra-high-density magnetic recording media can be achieved using this optimized top-down approach.

  19. Nitric oxide in the stress axis.

    Science.gov (United States)

    López-Figueroa, M O; Day, H E; Akil, H; Watson, S J

    1998-10-01

    In recent years nitric oxide (NO) has emerged as a unique biological messenger. NO is a highly diffusible gas, synthesized from L-arginine by the enzyme nitric oxide synthase (NOS). Three unique subtypes of NOS have been described, each with a specific distribution profile in the brain and periphery. NOS subtype I is present, among other areas, in the hippocampus, hypothalamus, pituitary and adrenal gland. Together these structures form the limbic-hypothalamic-pituitary-adrenal (LHPA) or stress axis, activation of which is one of the defining features of a stress response. Evidence suggests that NO may modulate the release of the stress hormones ACTH and corticosterone, and NOS activity and transcription is increased in the LHPA axis following various stressful stimuli. Furthermore, following activation of the stress axis, glucocorticoids are thought to down-regulate the transcription and activity of NOS via a feedback mechanism. Taken together, current data indicate a role for NO in the regulation of the LHPA axis, although at present this role is not well defined. It has been suggested that NO may act as a cellular communicator in plasticity and development, to facilitate the activation or the release of other neurotransmitters, to mediate immune responses, and/or as a vasodilator in the regulation of blood flow. In the following review we summarize some of the latest insights into the function of NO, with special attention to its relationship with the LHPA axis.

  20. Neutral axis as damage sensitive feature

    International Nuclear Information System (INIS)

    Sigurdardottir, D H; Glisic, B

    2013-01-01

    Structural health monitoring (SHM) is the process of continuously or periodically measuring structural parameters and the transformation of the collected data into information on real structural conditions. The centroid of stiffness is a universal parameter and its position in a cross-section can be evaluated for any load-carrying beam structure as the position of the neutral axis under conveniently chosen loads. Thus, a change in the position of the neutral axis within a cross-section can indicate a change in the position of the centroid of stiffness, i.e., unusual structural behaviors. This paper proposes a novel monitoring method based on deterministic and probabilistic determination of the position of the neutral axis under conveniently chosen conditions. Therefore, the method proposed in this paper is potentially applicable to a large variety of beam-like structures. Data from two existing structures were used to validate the method and assess its performance: Streicker Bridge at Princeton University and the US202/NJ23 highway overpass in Wayne, NJ. The results show that the neutral axis location is varying even when damage is not present. Reasons for this variation are determined and the accuracy in the evaluation assessed. This paper concludes that the position of the neutral axis can be evaluated with sufficient accuracy using static and dynamic strain measurements performed on appropriate time-scales and indicates its potential to be used as a damage sensitive feature. (paper)

  1. Neutral axis as damage sensitive feature

    Science.gov (United States)

    Sigurdardottir, D. H.; Glisic, B.

    2013-07-01

    Structural health monitoring (SHM) is the process of continuously or periodically measuring structural parameters and the transformation of the collected data into information on real structural conditions. The centroid of stiffness is a universal parameter and its position in a cross-section can be evaluated for any load-carrying beam structure as the position of the neutral axis under conveniently chosen loads. Thus, a change in the position of the neutral axis within a cross-section can indicate a change in the position of the centroid of stiffness, i.e., unusual structural behaviors. This paper proposes a novel monitoring method based on deterministic and probabilistic determination of the position of the neutral axis under conveniently chosen conditions. Therefore, the method proposed in this paper is potentially applicable to a large variety of beam-like structures. Data from two existing structures were used to validate the method and assess its performance: Streicker Bridge at Princeton University and the US202/NJ23 highway overpass in Wayne, NJ. The results show that the neutral axis location is varying even when damage is not present. Reasons for this variation are determined and the accuracy in the evaluation assessed. This paper concludes that the position of the neutral axis can be evaluated with sufficient accuracy using static and dynamic strain measurements performed on appropriate time-scales and indicates its potential to be used as a damage sensitive feature.

  2. IMAGING AN 80 au RADIUS DUST RING AROUND THE F5V STAR HD 157587

    International Nuclear Information System (INIS)

    Millar-Blanchaer, Maxwell A.; Moon, Dae-Sik; Wang, Jason J.; Kalas, Paul; Graham, James R.; Duchêne, Gaspard; Rosa, Robert J. De; Nielsen, Eric L.; Perrin, Marshall; Chen, Christine H.; Padgett, Deborah; Metchev, Stanimir; Bruzzone, Sebastian; Ammons, S. Mark; Bailey, Vanessa P.; Barman, Travis; Bulger, Joanna; Chilcote, Jeffrey; Cotten, Tara; Doyon, Rene

    2016-01-01

    We present H -band near-infrared polarimetric imaging observations of the F5V star HD 157587 obtained with the Gemini Planet Imager (GPI) that reveal the debris disk as a bright ring structure at a separation of ∼80–100 au. The new GPI data complement recent Hubble Space Telescope /STIS observations that show the disk extending out to over 500 au. The GPI image displays a strong asymmetry along the projected minor axis as well as a fainter asymmetry along the projected major axis. We associate the minor and major axis asymmetries with polarized forward scattering and a possible stellocentric offset, respectively. To constrain the disk geometry, we fit two separate disk models to the polarized image, each using a different scattering phase function. Both models favor a disk inclination of ∼70° and a 1.5 ± 0.6 au stellar offset in the plane of the sky along the projected major axis of the disk. We find that the stellar offset in the disk plane, perpendicular to the projected major axis is degenerate with the form of the scattering phase function and remains poorly constrained. The disk is not recovered in total intensity due in part to strong adaptive optics residuals, but we recover three point sources. Considering the system’s proximity to the galactic plane and the point sources’ positions relative to the disk, we consider it likely that they are background objects and unrelated to the disk’s offset from the star.

  3. IMAGING AN 80 au RADIUS DUST RING AROUND THE F5V STAR HD 157587

    Energy Technology Data Exchange (ETDEWEB)

    Millar-Blanchaer, Maxwell A.; Moon, Dae-Sik [Department of Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4 (Canada); Wang, Jason J.; Kalas, Paul; Graham, James R.; Duchêne, Gaspard; Rosa, Robert J. De [Astronomy Department, University of California Berkeley, Berkeley, CA 94720 (United States); Nielsen, Eric L. [SETI Institute, Carl Sagan Center, 189 Bernardo Avenue, Mountain View, CA 94043 (United States); Perrin, Marshall; Chen, Christine H. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Padgett, Deborah [Goddard Space Flight Center, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); Metchev, Stanimir; Bruzzone, Sebastian [Department of Physics and Astronomy, Centre for Planetary Science and Exploration, The University of Western Ontario, London, ON N6A 3K7 (Canada); Ammons, S. Mark [Lawrence Livermore National Laboratory, Livermore, CA 94551 (United States); Bailey, Vanessa P. [Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics, Stanford University, Stanford, CA, 94305 (United States); Barman, Travis [Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States); Bulger, Joanna [Subaru Telescope, NAOJ, 650 North A’ohoku Place, Hilo, HI 96720 (United States); Chilcote, Jeffrey [Dunlap Institute for Astronomy and Astrophysics, University of Toronto, Toronto, ON M5S 3H4 (Canada); Cotten, Tara [Department of Physics and Astronomy, University of Georgia, Athens, GA 30602 (United States); Doyon, Rene, E-mail: maxmb@astro.utoronto.ca [Institut de Recherche sur les Exoplanètes, Départment de Physique, Université de Montréal, Montréal QC H3C 3J7 (Canada); and others

    2016-11-01

    We present H -band near-infrared polarimetric imaging observations of the F5V star HD 157587 obtained with the Gemini Planet Imager (GPI) that reveal the debris disk as a bright ring structure at a separation of ∼80–100 au. The new GPI data complement recent Hubble Space Telescope /STIS observations that show the disk extending out to over 500 au. The GPI image displays a strong asymmetry along the projected minor axis as well as a fainter asymmetry along the projected major axis. We associate the minor and major axis asymmetries with polarized forward scattering and a possible stellocentric offset, respectively. To constrain the disk geometry, we fit two separate disk models to the polarized image, each using a different scattering phase function. Both models favor a disk inclination of ∼70° and a 1.5 ± 0.6 au stellar offset in the plane of the sky along the projected major axis of the disk. We find that the stellar offset in the disk plane, perpendicular to the projected major axis is degenerate with the form of the scattering phase function and remains poorly constrained. The disk is not recovered in total intensity due in part to strong adaptive optics residuals, but we recover three point sources. Considering the system’s proximity to the galactic plane and the point sources’ positions relative to the disk, we consider it likely that they are background objects and unrelated to the disk’s offset from the star.

  4. Effects of HfO{sub 2}/Co interface and Co/HfO{sub 2} interface on anomalous Hall behavior in perpendicular Co/Pt multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Shao-Long [Department of Materials Science and Engineering, College of Engineering, Peking University, Beijing 100871 (China); Yang, Guang [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); Teng, Jiao, E-mail: tengjiao@mater.ustb.edu.cn [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); Guo, Qi-Xun; Liu, Yi-Wei; Li, Xu-Jing [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China); Yu, Guang-Hua, E-mail: ghyu@mater.ustb.edu.cn [Department of Materials Physics and Chemistry, University of Science and Technology Beijing, Beijing 100083 (China)

    2017-07-01

    Highlights: • Anomalous Hall effect in perpendicular Co/Pt multilayers is studied. • Thermally stable AHE feature is obtained in [Pt/Co]{sub 3}/HfO{sub 2}/Pt multilayers. • Good thermal stability is due to enhanced intrinsic and side-jump contributions. - Abstract: Effects of the HfO{sub 2}/Co interface and the Co/HfO{sub 2} interface on thermal stability of anomalous Hall effect (AHE) in perpendicular Co/Pt multilayers have been studied. It is observed that thermally stable AHE behavior cannot be obtained in perpendicular Co/Pt multilayers with the HfO{sub 2}/Co interface, mainly due to Co-Pt interdiffusion during annealing. In contrast, thermally stable AHE feature is observed in perpendicular Co/Pt multilayers with the Co/HfO{sub 2} interface despite Co-Pt interdiffusion, which is owing to the enhancement of the side jump and intrinsic contributions to the AHE through interfacial modification after annealing.

  5. Monolayer Boron Nitride Substrate Interactions with Graphene Under In-Plane and Perpendicular Strains: A First-Principles Study

    Science.gov (United States)

    Behzad, Somayeh

    2018-04-01

    Effects of strain on the electronic and optical properties of graphene on monolayer boron nitride (BN) substrate are investigated using first-principle calculations based on density functional theory. Strain-free graphene/BN has a small band gap of 97 meV at the K point. The magnitude of band gap increases with in-plane biaxial strain while it decreases with the perpendicular uniaxial strain. The ɛ2 (ω ) spectrum of graphene/BN bilayer for parallel polarization shows red and blue shifts by applying the in-plane tensile and compressive strains, respectively. Also the positions of peaks in the ɛ2 (ω ) spectrum are not significantly changed under perpendicular strain. The calculated results indicate that graphene on the BN substrate has great potential in microelectronic and optoelectronic applications.

  6. Optical polarization position angle versus radio structure axis in Seyfert galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Antonucci, R R.J. [National Radio Astronomy Observatory, Charlottesville, VA (USA)

    1983-05-12

    The hypothesis that there are two polarization classes of Seyfert galaxies, analogous to the perpendicular and parallel radio galaxy groups, is investigated by examining optical polarimetry data. In the sample considered it is shown that all the Seyfert 1 galaxies have roughly parallel polarization while all the Seyfert 2 galaxies have roughly perpendicular polarizations. These alignment effects can be interpreted as being due to thin and thick scattering disks, respectively, surrounding the continuum sources. This would represent a fundamental difference between the two types of Seyfert galaxies.

  7. Angular dependence of magnetization reversal in epitaxial chromium telluride thin films with perpendicular magnetic anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Pramanik, Tanmoy, E-mail: pramanik.tanmoy@utexas.edu; Roy, Anupam, E-mail: anupam@austin.utexas.edu; Dey, Rik, E-mail: rikdey@utexas.edu; Rai, Amritesh; Guchhait, Samaresh; Movva, Hema C.P.; Hsieh, Cheng-Chih; Banerjee, Sanjay K.

    2017-09-01

    Highlights: • Perpendicular magnetic anisotropy in epitaxial Cr{sub 2}Te{sub 3} has been investigated. • Presence of a relatively strong second order anisotropy contribution is observed. • Magnetization reversal is explained quantitatively using a 1D defect model. • Relative roles of nucleation and pinning in magnetization reversal are discussed. • Domain structures and switching process are visualized by micromagnetic simulation. - Abstract: We investigate magnetic anisotropy and magnetization reversal mechanism in chromium telluride thin films grown by molecular beam epitaxy. We report existence of strong perpendicular magnetic anisotropy in these thin films, along with a relatively strong second order anisotropy contribution. The angular variation of the switching field observed from the magnetoresistance measurement is explained quantitatively using a one-dimensional defect model. The model reveals the relative roles of nucleation and pinning in the magnetization reversal, depending on the applied field orientation. Micromagnetic simulations are performed to visualize the domain structure and switching process.

  8. Perpendicular magnetic anisotropy and the magnetization process in CoFeB/Pd multilayer films

    DEFF Research Database (Denmark)

    Ngo, Duc-The; Quach, Duy-Truong; Hung, Tran Quang

    2014-01-01

    The perpendicular magnetic anisotropy (PMA) and dynamic magnetization-reversal process in [CoFeB t nm/Pd 1.0 nm]n(t = 0.4, 0.6, 0.8, 1.0 and 1.2 nm; n = 2 − 20) multilayer films have been studied by means of magnetic hysteresis and Kerr effect measurements. Strong and controllable PMA with an eff...

  9. A comprehensive comparison of perpendicular distance sampling methods for sampling downed coarse woody debris

    Science.gov (United States)

    Jeffrey H. Gove; Mark J. Ducey; Harry T. Valentine; Michael S. Williams

    2013-01-01

    Many new methods for sampling down coarse woody debris have been proposed in the last dozen or so years. One of the most promising in terms of field application, perpendicular distance sampling (PDS), has several variants that have been progressively introduced in the literature. In this study, we provide an overview of the different PDS variants and comprehensive...

  10. Optic axis-driven new horizons for hyperbolic metamaterials

    Directory of Open Access Journals (Sweden)

    Boardman Allan D.

    2015-01-01

    Full Text Available The broad assertion here is that the current hyperbolic metamaterial world is only partially served by investigations that incorporate only some limited version of anisotropy. Even modest deviations of the optic axis from the main propagation axis lead to new phase shifts, which not only compete with those created by absorption but end up dominating them. Some progress has been attempted in the literature by introducing the terms “asymmetric hyperbolic media”, but it appears that this kind of asymmetry only involves an optic axis at an angle to the interface of a uniaxial crystal. From a device point of view, many new prospects should appear and the outcomes of the investigations presented here yield a new general theory. It is emphasised that the orientation of the optic axis is a significant determinant in the resulting optical properties. Whereas for conventional anisotropic waveguides homogeneous propagating waves occur over a limited range of angular dispositions of the optic axis it is shown that for a hyperbolic guide a critical angular setting exists, above which the guided waves are always homogeneous. This has significant implications for metawaveguide designs. The resulting structures are more tolerant to optic axis misalignment.

  11. Gravitational disturbances generated by the Sun, Phobos and Deimos in orbital maneuvers around Mars with automatic correction of the semi-major axis

    International Nuclear Information System (INIS)

    Rocco, E M

    2015-01-01

    The objective of this work is to analyze orbital maneuvers of a spacecraft orbiting Mars, considering disturbance effects due to the gravitational attraction of the Sun, Phobos and Deimos, beyond the disturbances due to the gravitational potential of Mars. To simulate the trajectory, constructive aspects of the propulsion system were considered. Initially ideal thrusters, capable of applying infinite magnitude of the thrust, were used. Thus, impulsive optimal maneuvers were obtained by scanning the solutions of the Lambert's problem in order to select the maneuver of minimum fuel consumption. Due to the impossibility of applying an impulse, the orbital maneuver must be distributed in a propulsive arc around the position of the impulse given by the solution of the Lambert's problem. However the effect of the propulsive arc is not exactly equivalent to the application of an impulse due to the errors in magnitude and direction of applied thrust. Therefore, the influence of the thrusters’ capacity in the trajectory was evaluated for a more realistic model instead of the ideal case represented by the impulsive approach. Beyond the evaluation of the deviation in the orbital path, was considered an automatic correction of the semi-major axis using continuous low thrust controlled in closed loop to minimize the error in the trajectory after the application of the main thrust. (paper)

  12. Antiferromagnetic iridium-manganese intermediate layers for perpendicular recording media (invited)

    Science.gov (United States)

    Srinivasan, Kumar; Piramanayagam, S. N.; Sbiaa, Rachid; Kay, Yew Seng; Tan, Hang Khume; Wong, Seng Kai

    2009-04-01

    Current generation of cobalt-oxide-based perpendicular magnetic recording media uses single or dual ruthenium intermediate layers in order to grow crystallographically textured, and magnetically isolated granular media. In this work, the potential advantages of an antiferromagnetic iridium-manganese intermediate layer directly under the recording layer are highlighted. Owing to its close lattice matching with hexagonal cobalt, iridium-manganese which has the L12, or AuCu3-type crystal structure, can support the heteroepitaxial growth of the cobalt-based recording layer. In one of the media schemes described here, (111) textured iridium-manganese thin film was grown on 7.5 nm thick ruthenium layer. On the iridium-manganese as segregation layer, the Co-oxide-based magnetic recording layer showed perpendicular texture with Δθ50 below 4°, coercivity of over 4000 Oe alongside magnetic exchange decoupling, average grain sizes of 6 nm with distributions under 14%, and improved thermal stability. Measurements of the anisotropy constant did not show any significant change and even an IrMn capping layer was observed to improve the thermal stability. The possible mechanisms through which the IrMn layer could affect the thermal stability are hypothesized. The initial layers of the magnetic recording layer on IrMn segregation layers also showed exchange-decoupled and segregated grains, which is unlike that observed on Ru segregation layers. In a second media scheme, (111) textured iridium-manganese thin film was grown on a crystalline soft magnetic underlayer belonging on top of amorphous soft underlayers. In this scheme, partial pinning of the soft underlayer due to exchange-bias interaction with the IrMn layer was observed. This scheme offers the possibility to reduce the intermediate layer thickness, thus improve media writability, and with further optimization, could potentially facilitate the approach toward 1 Tbits/in.2.

  13. Ultra-fast three terminal perpendicular spin-orbit torque MRAM (Presentation Recording)

    Science.gov (United States)

    Boulle, Olivier; Cubukcu, Murat; Hamelin, Claire; Lamard, Nathalie; Buda-Prejbeanu, Liliana; Mikuszeit, Nikolai; Garello, Kevin; Gambardella, Pietro; Langer, Juergen; Ocker, Berthold; Miron, Mihai; Gaudin, Gilles

    2015-09-01

    The discovery that a current flowing in a heavy metal can exert a torque on a neighboring ferromagnet has opened a new way to manipulate the magnetization at the nanoscale. This "spin orbit torque" (SOT) has been demonstrated in ultrathin magnetic multilayers with structural inversion asymmetry (SIA) and high spin orbit coupling, such as Pt/Co/AlOx multilayers. We have shown that this torque can lead to the magnetization switching of a perpendicularly magnetized nanomagnet by an in-plane current injection. The manipulation of magnetization by SOT has led to a novel concept of magnetic RAM memory, the SOT-MRAM, which combines non volatility, high speed, reliability and large endurance. These features make the SOT-MRAM a good candidate to replace SRAM for non-volatile cache memory application. We will present the proof of concept of a perpendicular SOT-MRAM cell composed of a Ta/FeCoB/MgO/FeCoB magnetic tunnel junction and demonstrate ultra-fast (down to 300 ps) deterministic bipolar magnetization switching. Macrospin and micromagnetic simulations including SOT cannot reproduce the experimental results, which suggests that additional physical mechanisms are at stacks. Our results show that SOT-MRAM is fast, reliable and low power, which is promising for non-volatile cache memory application. We will also discuss recent experiments of magnetization reversal in ultrathin multilayers Pt/Co/AlOx by very short (<200 ps) current pulses. We will show that in this material, the Dzyaloshinskii-Moryia interaction plays a key role in the reversal process.

  14. Process and installation for welding nuclear fuel assembly grids

    International Nuclear Information System (INIS)

    Vere, B.; Mathevon, P.

    1985-01-01

    The invention proposes a process to weld two sets of perpendicular plates of which the end parts are made integral with a belt piece; the grid is held in a support frame with access openings to the points to be welded on the two faces and on the grid sides; the frame is moved on a mobile table by means of an orientation system along the perpendicular direction of an electron beam welding equipment; each joint to be welded is presented, rotating the frame through 90 deg about an axis and repeating the operation, and rotating the frame about a perpendicular axis and repeating the operation until all the joints on each side of the grid have been welded [fr

  15. The Collaborative Longitudinal Personality Disorders Study: baseline Axis I/II and II/II diagnostic co-occurrence.

    Science.gov (United States)

    McGlashan, T H; Grilo, C M; Skodol, A E; Gunderson, J G; Shea, M T; Morey, L C; Zanarini, M C; Stout, R L

    2000-10-01

    To describe baseline diagnostic co-occurrence in the Collaborative Longitudinal Personality Disorders Study. Six hundred and sixty-eight patients were reliably assessed with diagnostic interviews for DSM-IV Axis I and II disorders to create five groups: Schizotypal (STPD), Borderline (BPD), Avoidant (AVPD), Obsessive-Compulsive (OCPD) and Major Depressive Disorder (MDD) without personality disorder (PD). Mean number of Axis I lifetime diagnoses was 3.4; STPD and BPD groups had more diagnoses than AVPD, OCPD, and MDD groups. Significant Axis I co-occurrences emerged for Social Phobia/ AVPD, PTSD/BPD and Substance Use/BPD. Mean number of co-occurring PDs was 1.4; STPD had more than BPD group which had more than AVPD and OCPD groups. Significant PD co-occurrence emerged for: STPD/ Paranoid and Schizoid PDs, BPD with Antisocial and Dependent PDs, and lower frequency for OCPD/Antisocial PD. Diagnostic co-occurrences generally followed base rates, while significant departures resemble those of controlled literature.

  16. Perpendicular electron cyclotron emission from hot electrons in TMX-U

    International Nuclear Information System (INIS)

    James, R.A.; Ellis, R.F.; Lasnier, C.J.; Casper, T.A.; Celata, C.M.

    1984-01-01

    Perpendicular electron cyclotron emission (PECE) from the electron cyclotron resonant heating of hot electrons in TMX-U is measured at 30 to 40 and 50 to 75 GHz. This emission is optically thin and is measured at the midplane, f/sub ce/ approx. = 14 GHz, in either end cell. In the west end cell, the emission can be measured at different axial positions thus yielding the temporal history of the hot electron axial profile. These profiles are in excellent agreement with the axial diamagnetic signals. In addition, the PECE signal level correlates well with the diamagnetic signal over a wide range of hot electron densities. Preliminary results from theoretical modeling and comparisons with other diagnostics are also presented

  17. Analytical calculation of the torque exerted between two perpendicularly magnetized magnets

    Science.gov (United States)

    Allag, H.; Yonnet, J.-P.; Latreche, M. E. H.

    2011-04-01

    Analytical expressions of the torque on cuboidal permanent magnets are given. The only hypothesis is that the magnetizations are rigid, uniform, and perpendicularly oriented. The analytical calculation is made by replacing magnetizations by distributions of magnetic charges on the magnet poles. The torque expressions are obtained using the Lorentz force method. The results are valid for any relative magnet position, and the torque can be obtained with respect to any reference point. Although these expressions seem rather complicated, they enable an extremely fast and accurate torque calculation on a permanent magnet in the presence of a magnetic field of another permanent magnet.

  18. Room temperature microwave-assisted recording on 500-Gbpsi-class perpendicular medium

    Science.gov (United States)

    Nozaki, Y.; Ishida, N.; Soeno, Y.; Sekiguchi, K.

    2012-10-01

    Microwave-assisted recording on a 500-Gbpsi-class perpendicular medium was experimentally demonstrated at room temperature. Magnetization reversal under a radio-frequency magnetic field was measured by an electrically shorted coplanar waveguide, which enabled us to evaluate the change in the medium's ferromagnetic resonance spectrum. A frequency-dependent reduction in the switching field was clearly observed in response to a microwave impulse 50 ns in duration. A significant reduction of up to 30% in the coercive field was achieved by applying a microwave impulse with an amplitude of 25 dBm and a frequency of 15 GHz.

  19. Enhancement of perpendicular magnetic anisotropy and anomalous hall effect in Co/Ni multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yiwei; Zhang, Jingyan, E-mail: jyzhang@ustb.edu.cn; Jiang, Shaolong; Liu, Qianqian; Li, Xujing; Yu, Guanghua, E-mail: ghyu@mater.ustb.edu.cn

    2016-12-15

    The perpendicular magnetic anisotropy (PMA) and the anomalous Hall effect (AHE) in Co/Ni multilayer were optimized by manipulating its interface structure (inducing HfO{sub 2} capping layer and Pt insertion) and post-annealing treatment. A strong PMA can be obtained in Co/Ni multilayers with HfO{sub 2} capping layer even after annealing at 400 °C. The heavy metal Hf may improve the interfacial spin-orbit coupling, which responsible for the enhanced PMA and high annealing stability. Moreover, the multilayer containing HfO{sub 2} capping layer also exhibited high saturation anomalous Hall resistivity through post-annealing, which is 0.85 μΩ cm after annealing at 375 °C, 211% larger than in the sample at deposited state which is only 0.27 μΩ cm. The enhancement of AHE is mainly attributed to the interface scattering through post-annealing treatment. - Highlights: • The perpendicular magnetic anisotropy and anomalous Hall effect of Co/Ni multilayer films were studied. • The PMA thermal stability of the Co/Ni ML can be enhanced by HfO{sub 2} capping layer and Pt insertion. • The anomalous Hall resistivity of Co/Ni ML covered by HfO{sub 2} was enhanced by post-annealing treatment.

  20. INJECTION TO RAPID DIFFUSIVE SHOCK ACCELERATION AT PERPENDICULAR SHOCKS IN PARTIALLY IONIZED PLASMAS

    Energy Technology Data Exchange (ETDEWEB)

    Ohira, Yutaka, E-mail: ohira@phys.aoyama.ac.jp [Department of Physics and Mathematics, Aoyama Gakuin University, 5-10-1 Fuchinobe, Sagamihara 252-5258 (Japan)

    2016-08-10

    We present a three-dimensional hybrid simulation of a collisionless perpendicular shock in a partially ionized plasma for the first time. In this simulation, the shock velocity and upstream ionization fraction are v {sub sh} ≈ 1333 km s{sup −1} and f {sub i} ∼ 0.5, which are typical values for isolated young supernova remnants (SNRs) in the interstellar medium. We confirm previous two-dimensional simulation results showing that downstream hydrogen atoms leak into the upstream region and are accelerated by the pickup process in the upstream region, and large magnetic field fluctuations are generated both in the upstream and downstream regions. In addition, we find that the magnetic field fluctuations have three-dimensional structures and the leaking hydrogen atoms are injected into the diffusive shock acceleration (DSA) at the perpendicular shock after the pickup process. The observed DSA can be interpreted as shock drift acceleration with scattering. In this simulation, particles are accelerated to v ∼ 100 v {sub sh} ∼ 0.3 c within ∼100 gyroperiods. The acceleration timescale is faster than that of DSA in parallel shocks. Our simulation results suggest that SNRs can accelerate cosmic rays to 10{sup 15.5} eV (the knee) during the Sedov phase.

  1. Particle orbit analysis for LHD helical axis configurations

    International Nuclear Information System (INIS)

    Guasp, J.; Yamazaki, K.; Motojima, O.

    1993-04-01

    Fast ion orbits for helical magnetic axis configurations in LHD (Large Helical Device) are analyzed and compared with the standard circular axis case. Boundaries between passing and helically trapped particle regions show clear differences: in the non-planar axis case the helically trapped region spreads, near the magnetic axis, over a much wider band across the 90deg pitch angle value and shows a very marked asymmetry. The locally trapped particle region is also wider than in the standard case. The differences in the loss cone boundaries of the two cases are rather small, however, the effects of re-entering criteria are very important in both cases. On the contrary, effects of finite coil size are not significant. (author)

  2. The dual-axis solar tracking system efficiency improving via the drive power consumption optimization

    International Nuclear Information System (INIS)

    Rambhowan, Y.; Oree, V.

    2014-01-01

    A major drawback with active dual-axis solar tracking systems is that the power used by the driving mechanism is often drawn from the output power of the solar panel itself. The net energy gain of the photo-voltaic panel is therefore less than its maximum value. This work presents a novel design which uses a three-fold strategy to minimize the power consumed by the tracking mechanism whilst maintaining the power out-put of the photovoltaic panel near its optimal value. The results reveal that the improved tracking system has a significant energy gain of about 43.6% as compared to a fixed photovoltaic panel. Experiments further show that an increase of 1.6% in energy output is achieved over conventional precise dual-axis tracking system. (author)

  3. Energy Efficient Hybrid Dual Axis Solar Tracking System

    Directory of Open Access Journals (Sweden)

    Rashid Ahammed Ferdaus

    2014-01-01

    Full Text Available This paper describes the design and implementation of an energy efficient solar tracking system from a normal mechanical single axis to a hybrid dual axis. For optimizing the solar tracking mechanism electromechanical systems were evolved through implementation of different evolutional algorithms and methodologies. To present the tracker, a hybrid dual-axis solar tracking system is designed, built, and tested based on both the solar map and light sensor based continuous tracking mechanism. These light sensors also compare the darkness and cloudy and sunny conditions assisting daily tracking. The designed tracker can track sun’s apparent position at different months and seasons; thereby the electrical controlling device requires a real time clock device for guiding the tracking system in seeking solar position for the seasonal motion. So the combination of both of these tracking mechanisms made the designed tracker a hybrid one. The power gain and system power consumption are compared with a static and continuous dual axis solar tracking system. It is found that power gain of hybrid dual axis solar tracking system is almost equal to continuous dual axis solar tracking system, whereas the power saved in system operation by the hybrid tracker is 44.44% compared to the continuous tracking system.

  4. Magnetocrystalline anisotropy and its electric-field-assisted switching of Heusler-compound-based perpendicular magnetic tunnel junctions

    International Nuclear Information System (INIS)

    Bai, Zhaoqiang; Wu, Qingyun; Zeng, Minggang; Feng, Yuan Ping; Shen, Lei; Cai, Yongqing; Han, Guchang

    2014-01-01

    Employing density functional theory combined with the non-equilibrium Green's function formalism, we systematically investigate the structural, magnetic and magnetoelectric properties of the Co 2 FeAl(CFA)/MgO interface, as well as the spin-dependent transport characteristics of the CFA/MgO/CFA perpendicular magnetic tunnel junctions (p-MTJs). We find that the structure of the CFA/MgO interface with the oxygen-top FeAl termination has high thermal stability, which is protected by the thermodynamic equilibrium limit. Furthermore, this structure is found to have perpendicular magnetocrystalline anisotropy (MCA). Giant electric-field-assisted modifications of this interfacial MCA through magnetoelectric coupling are demonstrated with an MCA coefficient of up to 10 −7 erg V −1 cm. In addition, our non-collinear spin transport calculations of the CFA/MgO/CFA p-MTJ predict a good magnetoresistance performance of the device. (paper)

  5. Triple axis spectrometers

    International Nuclear Information System (INIS)

    Clausen, K.N.

    1997-01-01

    Conventional triple-axis neutron spectroscopy was developed by Brockhouse over thirty years ago' and remains today a versatile and powerful tool for probing the dynamics of condensed matter. The original design of the triple axis spectrometer is technically simple and probes momentum and energy space on a point-by-point basis. This ability to systematically probe the scattering function in a way which only requires a few angles to be moved under computer control and where the observed data in general can be analysed using a pencil and graph paper or a simple fitting routine, has been essential for the success of the method. These constraints were quite reasonable at the time the technique was developed. Advances in computer based data acquisition, neutron beam optics, and position sensitive area detectors have been gradually implemented on many triple axis spectrometer spectrometers, but the full potential of this has not been fully exploited yet. Further improvement in terms of efficiency (beyond point by point inspection) and increased sensitivity (use of focusing optics whenever the problem allows it) could easily be up to a factor of 10-20 over present instruments for many problems at a cost which is negligible compared to that of increasing the flux of the source. The real cost will be in complexity - finding the optimal set-up for a given scan and interpreting the data as the they are taken. On-line transformation of the data for an appropriate display in Q, ω space and analysis tools will be equally important for this task, and the success of these new ideas will crucially depend on how well we solve these problems. (author)

  6. Solid state controller three axes controller

    Science.gov (United States)

    Bailey, C. L., Jr. (Inventor)

    1973-01-01

    The reported flight controller features a handle grip which is mounted on a longitudinally extending control element. The handle grip is pivotally mounted on the control element about a pitch axis which is perpendicular to the longitudinal axis through the control element. The pivotal mounting includes a resilient force mounting mechanism which centers the grip relative to the control element. Rotation of the handle grip produces a direct rotation of a transducer element in a transducer which provides an electrical indication of the rotative movement about three mutually perpendicular axes.

  7. Preparation of Fe-Pt perpendicular double-layered media with high electric resistivity backlayer

    International Nuclear Information System (INIS)

    Uchida, Masaru; Suzuki, Toshio; Ouchi, Kazuhiro

    2001-01-01

    High electric resistivity materials, oxide-added Fe-Si, were investigated as a soft-magnetic backlayer for Fe-Pt perpendicular double-layered media. It was found that there is a possibility of using (Fe-Si)-MgO as a backlayer. To promote a hetero-epitaxial growth of ordered Fe-Pt FCT(0 0 1), the backlayer needed a BCC(2 0 0) crystal orientation, in a situation where surface topology also played an important role

  8. Microbiota-Brain-Gut Axis and Neurodegenerative Diseases.

    Science.gov (United States)

    Quigley, Eamonn M M

    2017-10-17

    The purposes of this review were as follows: first, to provide an overview of the gut microbiota and its interactions with the gut and the central nervous system (the microbiota-gut-brain axis) in health, second, to review the relevance of this axis to the pathogenesis of neurodegenerative diseases, such as Parkinson's disease, and, finally, to assess the potential for microbiota-targeted therapies. Work on animal models has established the microbiota-gut-brain axis as a real phenomenon; to date, the evidence for its operation in man has been limited and has been confronted by considerable logistical challenges. Animal and translational models have incriminated a disturbed gut microbiota in a number of CNS disorders, including Parkinson's disease; data from human studies is scanty. While a theoretical basis can be developed for the use of microbiota-directed therapies in neurodegenerative disorders, support is yet to come from high-quality clinical trials. In theory, a role for the microbiota-gut-brain axis is highly plausible; clinical confirmation is awaited.

  9. A psychology of the human brain-gut-microbiome axis.

    Science.gov (United States)

    Allen, Andrew P; Dinan, Timothy G; Clarke, Gerard; Cryan, John F

    2017-04-01

    In recent years, we have seen increasing research within neuroscience and biopsychology on the interactions between the brain, the gastrointestinal tract, the bacteria within the gastrointestinal tract, and the bidirectional relationship between these systems: the brain-gut-microbiome axis. Although research has demonstrated that the gut microbiota can impact upon cognition and a variety of stress-related behaviours, including those relevant to anxiety and depression, we still do not know how this occurs. A deeper understanding of how psychological development as well as social and cultural factors impact upon the brain-gut-microbiome axis will contextualise the role of the axis in humans and inform psychological interventions that improve health within the brain-gut-microbiome axis. Interventions ostensibly aimed at ameliorating disorders in one part of the brain-gut-microbiome axis (e.g., psychotherapy for depression) may nonetheless impact upon other parts of the axis (e.g., microbiome composition and function), and functional gastrointestinal disorders such as irritable bowel syndrome represent a disorder of the axis, rather than an isolated problem either of psychology or of gastrointestinal function. The discipline of psychology needs to be cognisant of these interactions and can help to inform the future research agenda in this emerging field of research. In this review, we outline the role psychology has to play in understanding the brain-gut-microbiome axis, with a focus on human psychology and the use of research in laboratory animals to model human psychology.

  10. A psychology of the human brain–gut–microbiome axis

    Science.gov (United States)

    Allen, Andrew P.; Dinan, Timothy G.; Clarke, Gerard

    2017-01-01

    Abstract In recent years, we have seen increasing research within neuroscience and biopsychology on the interactions between the brain, the gastrointestinal tract, the bacteria within the gastrointestinal tract, and the bidirectional relationship between these systems: the brain–gut–microbiome axis. Although research has demonstrated that the gut microbiota can impact upon cognition and a variety of stress‐related behaviours, including those relevant to anxiety and depression, we still do not know how this occurs. A deeper understanding of how psychological development as well as social and cultural factors impact upon the brain–gut–microbiome axis will contextualise the role of the axis in humans and inform psychological interventions that improve health within the brain–gut–microbiome axis. Interventions ostensibly aimed at ameliorating disorders in one part of the brain–gut–microbiome axis (e.g., psychotherapy for depression) may nonetheless impact upon other parts of the axis (e.g., microbiome composition and function), and functional gastrointestinal disorders such as irritable bowel syndrome represent a disorder of the axis, rather than an isolated problem either of psychology or of gastrointestinal function. The discipline of psychology needs to be cognisant of these interactions and can help to inform the future research agenda in this emerging field of research. In this review, we outline the role psychology has to play in understanding the brain–gut–microbiome axis, with a focus on human psychology and the use of research in laboratory animals to model human psychology. PMID:28804508

  11. Determination of crack depth in aluminum using eddy currents and GMR sensors

    Science.gov (United States)

    Lopes Ribeiro, A.; Pasadas, D.; Ramos, H. G.; Rocha, T.

    2015-03-01

    In this paper we use eddy currents to determine the depth of linear cracks in aluminum plates. A constant field probe is used to generate the spatially uniform excitation field and a single axis giant magneto-resistor (GMR) sensor is used to measure the eddy currents magnetic field. Different depths were machined in one aluminum plate with 4 mm of thickness. By scanning those cracks the magnetic field components parallel and perpendicular to the crack's line were measured when the eddy currents were launched perpendicularly to the crack's line. To characterize one crack in a plate of a given thickness and material, the experimental procedure was defined. The plate surface is scanned to detect and locate one crack. The acquired data enables the determination of the crack's length and orientation. A second scanning is performed with the excitation current perpendicular to the crack and the GMR sensing axis perpendicular and parallel to the crack's line.

  12. Observations of the spatial and temporal structure of field-aligned beam and gyrating ring distributions at the quasi-perpendicular bow shock with Cluster CIS

    Directory of Open Access Journals (Sweden)

    E. Möbius

    2001-09-01

    Full Text Available During the early orbit phase, the Cluster spacecraft have repeatedly crossed the perpendicular Earth’s bow shock and provided the first multi-spacecraft measurements. We have analyzed data from the Cluster Ion Spectrometry experiment (CIS, which observes the 3D-ion distribution function of the major species in the energy range of 5 eV to 40 keV with a 4 s resolution. Beams of reflected ions were observed simultaneously at all spacecraft locations and could be tracked from upstream to the shock itself. They were found to originate from the same distribution of ions that constitutes the reflected gyrating ions, which form a ring distribution in the velocity space immediately upstream and downstream of the shock. This observation suggests a common origin of ring and beam populations at quasi-perpendicular shocks in the form of specular reflection and immediate pitch angle scattering. Generally, the spatial evolution across the shock is very similar on all spacecraft, but phased in time according to their relative location. However, a distinct temporal structure of the ion fluxes in the field-aligned beam is observed that varies simultaneously on all spacecraft. This is likely to reflect the variations in the reflection and scattering efficiencies.Key words. Interplanetary physics (planetary bow shocks; energetic particles; instruments and techniques

  13. Role of curvatures in determining the characteristics of a string vibrating against a doubly curved obstacle

    Science.gov (United States)

    Singh, Harkirat; Wahi, Pankaj

    2017-08-01

    The motion of a string in the presence of a doubly curved obstacle is investigated. A mathematical model has been developed for a general shape of the obstacle. However, detailed analysis has been performed for a shape relevant to the Indian stringed musical instruments like Tanpura and Sitar. In particular, we explore the effect of obstacle's curvature in the plane perpendicular to the string axis on its motion. This geometrical feature of the obstacle introduces a coupling between motions in mutually perpendicular directions over and above the coupling due to the stretching nonlinearity. We find that only one planar motion is possible for our system. Small amplitude planar motions are stable to perturbations in the perpendicular direction resulting in non-whirling motions while large amplitude oscillations lead to whirling motions. The critical amplitude of oscillations, across which there is a transition in the qualitative behavior of the non-planar trajectories, is determined using Floquet theory. Our analysis reveals that a small obstacle curvature in a direction perpendicular to the string axis leads to a considerable reduction in the critical amplitudes required for initiation of whirling motions. Hence, this obstacle curvature has a destabilizing effect on the planar motions in contrast to the curvature along the string axis which stabilizes planar motions.

  14. Quantitative DIC microscopy using an off-axis self-interference approach.

    Science.gov (United States)

    Fu, Dan; Oh, Seungeun; Choi, Wonshik; Yamauchi, Toyohiko; Dorn, August; Yaqoob, Zahid; Dasari, Ramachandra R; Feld, Michael S

    2010-07-15

    Traditional Normarski differential interference contrast (DIC) microscopy is a very powerful method for imaging nonstained biological samples. However, one of its major limitations is the nonquantitative nature of the imaging. To overcome this problem, we developed a quantitative DIC microscopy method based on off-axis sample self-interference. The digital holography algorithm is applied to obtain quantitative phase gradients in orthogonal directions, which leads to a quantitative phase image through a spiral integration of the phase gradients. This method is practically simple to implement on any standard microscope without stringent requirements on polarization optics. Optical sectioning can be obtained through enlarged illumination NA.

  15. Astigmatic single photon emission computed tomography imaging with a displaced center of rotation

    International Nuclear Information System (INIS)

    Wang, H.; Smith, M.F.; Stone, C.D.; Jaszczak, R.J.

    1998-01-01

    A filtered backprojection algorithm is developed for single photon emission computed tomography (SPECT) imaging with an astigmatic collimator having a displaced center of rotation. The astigmatic collimator has two perpendicular focal lines, one that is parallel to the axis of rotation of the gamma camera and one that is perpendicular to this axis. Using SPECT simulations of projection data from a hot rod phantom and point source arrays, it is found that a lack of incorporation of the mechanical shift in the reconstruction algorithm causes errors and artifacts in reconstructed SPECT images. The collimator and acquisition parameters in the astigmatic reconstruction formula, which include focal lengths, radius of rotation, and mechanical shifts, are often partly unknown and can be determined using the projections of a point source at various projection angles. The accurate determination of these parameters by a least squares fitting technique using projection data from numerically simulated SPECT acquisitions is studied. These studies show that the accuracy of parameter determination is improved as the distance between the point source and the axis of rotation of the gamma camera is increased. The focal length to the focal line perpendicular to the axis of rotation is determined more accurately than the focal length to the focal line parallel to this axis. copyright 1998 American Association of Physicists in Medicine

  16. Perpendicular magnetic anisotropy and magnetization dynamics in oxidized CoFeAl films

    Science.gov (United States)

    Wu, Di; Zhang, Zhe; Li, Le; Zhang, Zongzhi; Zhao, H. B.; Wang, J.; Ma, B.; Jin, Q. Y.

    2015-07-01

    Half-metallic Co-based full-Heusler alloys with perpendicular magnetic anisotropy (PMA), such as Co2FeAl in contact with MgO, are receiving increased attention recently due to its full spin polarization for high density memory applications. However, the PMA induced by MgO interface can only be realized for very thin magnetic layers (usually below 1.3 nm), which would have strong adverse effects on the material properties of spin polarization, Gilbert damping parameter, and magnetic stability. In order to solve this issue, we fabricated oxidized Co50Fe25Al25 (CFAO) films with proper thicknesses without employing the MgO layer. The samples show controllable PMA by tuning the oxygen pressure (PO2) and CFAO thickness (tCFAO), large perpendicular anisotropy field of ~8.0 kOe can be achieved at PO2 = 12% for the sample of tCFAO = 2.1 nm or at PO2 = 7% for tCFAO = 2.8 nm. The loss of PMA at thick tCFAO or high PO2 results mainly from the formation of large amount of CoFe oxides, which are superparamagnetic at room temperature but become hard magnetic at low temperatures. The magnetic CFAO films, with strong PMA in a relatively wide thickness range and small intrinsic damping parameter below 0.028, would find great applications in developing advanced spintronic devices.

  17. Helical axis stellarator equilibrium model

    International Nuclear Information System (INIS)

    Koniges, A.E.; Johnson, J.L.

    1985-02-01

    An asymptotic model is developed to study MHD equilibria in toroidal systems with a helical magnetic axis. Using a characteristic coordinate system based on the vacuum field lines, the equilibrium problem is reduced to a two-dimensional generalized partial differential equation of the Grad-Shafranov type. A stellarator-expansion free-boundary equilibrium code is modified to solve the helical-axis equations. The expansion model is used to predict the equilibrium properties of Asperators NP-3 and NP-4. Numerically determined flux surfaces, magnetic well, transform, and shear are presented. The equilibria show a toroidal Shafranov shift

  18. Perpendicular magnetic anisotropy in Ta|Co40Fe40B20|MgAl2O4 structures and perpendicular CoFeB|MgAl2O4|CoFeB magnetic tunnel junction

    KAUST Repository

    Tao, B. S.

    2014-09-08

    Magnetic properties of Co40Fe40B20(CoFeB) thin films sandwiched between Ta and MgAl2O4layers have been systematically studied. For as-grown state, Ta/CoFeB/MgAl2O4structures exhibit good perpendicular magnetic anisotropy (PMA) with interface anisotropy Ki=1.22erg/cm2, which further increases to 1.30erg/cm2after annealing, while MgAl2O4/CoFeB/Ta multilayer shows in-plane magnetic anisotropy and must be annealed in order to achieve PMA. For bottom CoFeB layer, the thickness window for PMA is from 0.6 to 1.0nm, while that for top CoFeB layer is between 0.8 and 1.4nm. Perpendicular magnetic tunnel junctions (p-MTJs) with a core structure of CoFeB/MgAl2O4/CoFeB have also been fabricated and tunneling magnetoresistance ratio of about 36% at room temperature and 63% at low temperature have been obtained. The intrinsic excitations in the p-MTJs have been identified by inelastic electron-tunneling spectroscopy.

  19. Perpendicular magnetic anisotropy in Ta|Co40Fe40B20|MgAl2O4 structures and perpendicular CoFeB|MgAl2O4|CoFeB magnetic tunnel junction

    KAUST Repository

    Tao, B. S.; Li, D. L.; Yuan, Z. H.; Liu, H. F.; Ali, S. S.; Feng, J. F.; Wei, H. X.; Han, X. F.; Liu, Y.; Zhao, Y. G.; Zhang, Q.; Guo, Zaibing; Zhang, Xixiang

    2014-01-01

    Magnetic properties of Co40Fe40B20(CoFeB) thin films sandwiched between Ta and MgAl2O4layers have been systematically studied. For as-grown state, Ta/CoFeB/MgAl2O4structures exhibit good perpendicular magnetic anisotropy (PMA) with interface anisotropy Ki=1.22erg/cm2, which further increases to 1.30erg/cm2after annealing, while MgAl2O4/CoFeB/Ta multilayer shows in-plane magnetic anisotropy and must be annealed in order to achieve PMA. For bottom CoFeB layer, the thickness window for PMA is from 0.6 to 1.0nm, while that for top CoFeB layer is between 0.8 and 1.4nm. Perpendicular magnetic tunnel junctions (p-MTJs) with a core structure of CoFeB/MgAl2O4/CoFeB have also been fabricated and tunneling magnetoresistance ratio of about 36% at room temperature and 63% at low temperature have been obtained. The intrinsic excitations in the p-MTJs have been identified by inelastic electron-tunneling spectroscopy.

  20. Automated Slicing for a Multi-Axis Metal Deposition System (Preprint)

    Science.gov (United States)

    2006-09-01

    experimented with different materials like H13 tool steel to build the part. Following the same slicing and scanning toolpath result, there is a geometric...and analysis tool -centroidal axis. Similar to medial axis, it contains geometry and topological information but is significantly computationally...geometry reasoning and analysis tool -centroidal axis. Similar to medial axis, it contains geometry and topological information but is significantly

  1. Microstructure in two- and three-dimensional hybrid simulations of perpendicular collisionless shocks

    Czech Academy of Sciences Publication Activity Database

    Burgess, D.; Hellinger, Petr; Gingell, I.; Trávníček, Pavel M.

    2016-01-01

    Roč. 82, č. 4 (2016), 905820401/1-905820401/23 ISSN 0022-3778 Institutional support: RVO:68378289 Keywords : ion-acceleration * numerical simulations * bow shock * electron acceleration * cluster observations * self-reformation * magnetic-field * whistler waves * injection * nonstationarity Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.160, year: 2016 https://www.cambridge.org/core/ journals /journal-of-plasma-physics/article/microstructure-in-two-and-three-dimensional-hybrid-simulations-of-perpendicular-collisionless-shocks/F964EF89FB14A6504A49CFAD54970E2B

  2. Applying the parton model to the fast hadrons at low p(perpendicular)

    International Nuclear Information System (INIS)

    Teper, M.J.

    1978-03-01

    The spectra of fast produced hadrons at low p (perpendicular) are discussed within the context of the parton model. Several specific models are critically considered from the experimental and theoretical point of view. Attention is focussed on the quark recombination model and improvements are suggested to overcome its problems; in particular the concept of a chameleon quark is introduced. Contamination of pseudoscalar fragments of the proton by vector meson decay is shown to be small for x > approximately 0.5. Predictions for polarised pp scattering are made. (author)

  3. Interfacial exchange coupling and magnetization reversal in perpendicular [Co/Ni]N/TbCo composite structures.

    Science.gov (United States)

    Tang, M H; Zhang, Zongzhi; Tian, S Y; Wang, J; Ma, B; Jin, Q Y

    2015-06-15

    Interfacial exchange coupling and magnetization reversal characteristics in the perpendicular heterostructures consisting of an amorphous ferrimagnetic (FI) TbxCo(100-x) alloy layer exchange-coupled with a ferromagnetic (FM) [Co/Ni]N multilayer have been investigated. As compared with pure TbxCo(100-x) alloy, the magnetization compensation composition of the heterostructures shift to a higher Tb content, implying Co/Ni also serves to compensate the Tb moment in TbCo layer. The net magnetization switching field Hc⊥ and interlayer interfacial coupling field Hex, are not only sensitive to the magnetization and thickness of the switched TbxCo(100-x) or [Co/Ni]N layer, but also to the perpendicular magnetic anisotropy strength of the pinning layer. By tuning the layer structure we achieve simultaneously both large Hc⊥ = 1.31 T and Hex = 2.19 T. These results, in addition to the fundamental interest, are important to understanding of the interfacial coupling interaction in the FM/FI heterostructures, which could offer the guiding of potential applications in heat-assisted magnetic recording or all-optical switching recording technique.

  4. Optical performance of inclined south-north single-axis tracked solar panels

    International Nuclear Information System (INIS)

    Li, Zhimin; Liu, Xinyue; Tang, Runsheng

    2010-01-01

    To investigate optical performance of the inclined south-north single-axis (ISN-axis, in short) tracked solar panels, a mathematical procedure to estimate the annual collectible radiation on fixed and tracked panels was suggested based on solar geometry and monthly horizontal radiation. For solar panels tracking about ISN-axis, the yearly optimal tilt-angle of ISN-axis for maximizing annual solar gain was about 3 o deviating from the site latitude in most of China except in areas with poor solar resources, and the maximum annual collectible radiation on ISN-axis tracked panels was about 97-98% of that on dual-axis tracked panels; whereas for ISN-axis tracked panels with the tilt-angle of ISN-axis being adjusted four times in a year at three fixed tilt-angles, the annual collectible radiation was almost close to that on dual-axis tracked panels, the optimum date of tilt-angle adjustment of ISN-axis was 23 days from the equinoxes, and the optimum tilt-angle adjustment value for each adjustment was about 22 o . Compared to fixed south-facing solar panels inclined at an optimal tilt-angle, the increase in the annual solar gain due to using ISN-axis sun tracking was above 30% in the areas with abundant solar resources and less than 20% in the areas with poor solar resources.

  5. The impact of inertial forces on morphing wind turbine blade in vertical axis configuration

    International Nuclear Information System (INIS)

    Butbul, Jonathan; MacPhee, David; Beyene, Asfaw

    2015-01-01

    Highlights: • A novel flexible VAWT has been experimentally tested alongside numerically simulations. • Using FEA and CFD, direction of blade bending was predicted from inertial and aerodynamic forces. • High-speed camera footage has been used to validate the model. • The flexible VAWT was found to self-start in the majority of tests, while the rigid one did not. • It is suggested that flexible VAWTs can have improved performance in part-load applications. - Abstract: A novel flexible blade concept with the ability to morph and geometrically adapt to changing flow conditions has been proposed to improve part-load performance of horizontal-axis wind turbines. The extension of these benefits to a vertical axis wind turbine would make wind technology a more competitive player in the energy market. Both flexible and rigid wind turbine rotor blades for vertical axis application were modeled, designed, manufactured and tested. Their performances were tested in a low speed wind tunnel. The predicted magnitude and direction of blade morph was validated using a high speed camera as well as finite element analysis. The comparative results of straight rigid and straight morphing blades show that the coefficient of performance greatly depends on the tip speed ratio. Overall, the morphing blade has better performance at low RPMs, but the rigid blade performed better at high RPMs. It was observed that the flexible blade self-started in the majority of the experiments. At high RPM, the centrifugal force overwhelmed the lift force, bending the flexible blade out of phase in an undesired direction increasing drag and therefore reducing the coefficient of performance

  6. Use of bias sputtering to enhance decoupling in oxide composite perpendicular recording media

    International Nuclear Information System (INIS)

    Lee, Hwan-Soo; Bain, James A.; Laughlin, David E.

    2007-01-01

    The effects of substrate bias on two types of oxide composite perpendicular recording media CoCrPt-SiO 2 and FePt-MgO were investigated. The use of substrate bias greatly modified the thin film microstructure and resulted in the enhanced grain decoupling in the films. The growth characteristics due to preferential resputtering were interpreted to arise mainly from weak surface bonding to the growing films for nontextured growth, combined with strong cohesion for the textured growth

  7. Depth-Dependent Anisotropies of Amides and Sugar in Perpendicular and Parallel Sections of Articular Cartilage by Fourier Transform Infrared Imaging (FTIRI)

    Science.gov (United States)

    Xia, Yang; Mittelstaedt, Daniel; Ramakrishnan, Nagarajan; Szarko, Matthew; Bidthanapally, Aruna

    2010-01-01

    Full thickness blocks of canine humeral cartilage were microtomed into both perpendicular sections and a series of 100 parallel sections, each 6 μm thick. Fourier Transform Infrared Imaging (FTIRI) was used to image each tissue section eleven times under different infrared polarizations (from 0° to 180° polarization states in 20° increments and with an additional 90° polarization), at a spatial resolution of 6.25 μm and a wavenumber step of 8 cm−1. With increasing depth from the articular surface, amide anisotropies increased in the perpendicular sections and decreased in the parallel sections. Both types of tissue sectioning identified a 90° difference between amide I and amide II in the superficial zone of cartilage. The fibrillar distribution in the parallel sections from the superficial zone was shown to not be random. Sugar had the greatest anisotropy in the upper part of the radial zone in the perpendicular sections. The depth-dependent anisotropic data were fitted with a theoretical equation that contained three signature parameters, which illustrate the arcade structure of collagens with the aid of a fibril model. Infrared imaging of both perpendicular and parallel sections provides the possibility of determining the three-dimensional macromolecular structures in articular cartilage. Being sensitive to the orientation of the macromolecular structure in healthy articular cartilage aids the prospect of detecting the early onset of the tissue degradation that may lead to pathological conditions such as osteoarthritis. PMID:21274999

  8. Methods for characterizing magnetic footprints of perpendicular magnetic recording writer heads

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shaoping, E-mail: shaoping.li@wdc.com; Lin, Ed; George, Zach; Terrill, Dave; Mendez, H.; Santucci, J.; Yie, Derek [Western Digital Corp., 44100 Osgood Road, Fremont, California 94539 (United States)

    2014-05-07

    In this work, the magnetic footprints, along with some of its dynamic features in recording process, of perpendicular magnetic recording writer heads have been characterized by using three different techniques. Those techniques are the spin-stand stationary footprint technique, the spin-stand dynamic footprint technique, and the coherent writing technique combined with magnetic force microscope imaging method. The characteristics of those techniques have been compared to one another. It was found experimentally that the spin-stand stationary method could not precisely catch some peculiar recording dynamics of the write heads in certain conditions. The advantages and disadvantages among all those techniques are also examined and discussed in detail.

  9. Methods for characterizing magnetic footprints of perpendicular magnetic recording writer heads

    International Nuclear Information System (INIS)

    Li, Shaoping; Lin, Ed; George, Zach; Terrill, Dave; Mendez, H.; Santucci, J.; Yie, Derek

    2014-01-01

    In this work, the magnetic footprints, along with some of its dynamic features in recording process, of perpendicular magnetic recording writer heads have been characterized by using three different techniques. Those techniques are the spin-stand stationary footprint technique, the spin-stand dynamic footprint technique, and the coherent writing technique combined with magnetic force microscope imaging method. The characteristics of those techniques have been compared to one another. It was found experimentally that the spin-stand stationary method could not precisely catch some peculiar recording dynamics of the write heads in certain conditions. The advantages and disadvantages among all those techniques are also examined and discussed in detail

  10. Methods for characterizing magnetic footprints of perpendicular magnetic recording writer heads

    Science.gov (United States)

    Li, Shaoping; Lin, Ed; George, Zach; Terrill, Dave; Mendez, H.; Santucci, J.; Yie, Derek

    2014-01-01

    In this work, the magnetic footprints, along with some of its dynamic features in recording process, of perpendicular magnetic recording writer heads have been characterized by using three different techniques. Those techniques are the spin-stand stationary footprint technique, the spin-stand dynamic footprint technique, and the coherent writing technique combined with magnetic force microscope imaging method. The characteristics of those techniques have been compared to one another. It was found experimentally that the spin-stand stationary method could not precisely catch some peculiar recording dynamics of the write heads in certain conditions. The advantages and disadvantages among all those techniques are also examined and discussed in detail. PMID:24753633

  11. Proper time axis of a closed relativistic system

    International Nuclear Information System (INIS)

    Chernikov, N.A.; Fadeev, N.G.; Shavokhina, N.S.

    1997-01-01

    The definition of a proper time axis of a closed relativistic system of colliding particles is given. The solution of the proper time axis problem is presented. If the light velocity c equals the imaginary unit i, then in the case of a plane motion of the system the problem about the proper time axis turns out to be equivalent to the known in engineering mechanics problem about the reduction of any system of forces, applied to a rigid body, to the dynamic screw. In the general case, when c=i, the problem about the proper time axis turns out to be equivalent to the problem about the reduction to the dynamic screw of a system of forces, applied to a rigid body in a four-dimensional Euclidean space

  12. THE ANISOTROPIC TWO-POINT CORRELATION FUNCTIONS OF THE NONLINEAR TRACELESS TIDAL FIELD IN THE PRINCIPAL-AXIS FRAME

    International Nuclear Information System (INIS)

    Lee, Jounghun; Hahn, Oliver; Porciani, Cristiano

    2009-01-01

    Galaxies on the largest scales of the universe are observed to be embedded in the filamentary cosmic web, which is shaped by the nonlinear tidal field. As an efficient tool to quantitatively describe the statistics of this cosmic web, we present the anisotropic two-point correlation functions of the nonlinear traceless tidal field in the principal-axis frame, which are measured using numerical data from an N-body simulation. We show that both the nonlinear density and traceless tidal fields are more strongly correlated along the directions perpendicular to the eigenvectors associated with the largest eigenvalues of the local tidal field. The correlation length scale of the traceless tidal field is found to be ∼20 h -1 Mpc, which is much larger than that of the density field ∼5 h -1 Mpc. We also provide analytic fitting formulae for the anisotropic correlation functions of the traceless tidal field, which turn out to be in excellent agreement with the numerical results. We expect that our numerical results and analytical formula are useful to disentangle cosmological information from the filamentary network of the large-scale structures.

  13. Quantitative comparison between two geometrical layouts for diffraction enhanced imaging

    International Nuclear Information System (INIS)

    Huang Wanxia; Yuan Qingxi; Zhu Peiping; Wang Junyue; Shu Hang; Chen Bo; Hu Tiandou; Wu Ziyu

    2007-01-01

    Diffraction enhanced imaging (DEI) with two crystals has been performed at the 4W1A beamline at Beijing Synchrotron Radiation Facility (BSRF). Two different crystal geometrical layouts were used to collect images, in the first layout the rotation axis of the crystal has been set perpendicular to the orbital plane while in the second the axis is parallel to the orbital plane. Performance comparison between the two layouts is discussed in terms of thermal expansion of the crystal induced by the heat load, imaging homogeneity, spatial resolution and angular resolution. From both experimental and theoretical data we show that the best images may be obtained with the optical layout in which the rotation axis of the crystals is perpendicular to the orbital plane

  14. Quantitative comparison between two geometrical layouts for diffraction enhanced imaging

    Energy Technology Data Exchange (ETDEWEB)

    Huang Wanxia; Yuan Qingxi [Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, CAS, Beijing (China); Zhu Peiping [Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, CAS, Beijing (China)], E-mail: zhupp@ihep.ac.cn; Wang Junyue; Shu Hang [Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, CAS, Beijing (China); Chen Bo [Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, CAS, Beijing (China); Department of Physics, University of Science and Technology of China, Hefei (China); Hu Tiandou [Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, CAS, Beijing (China); Wu Ziyu [Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, CAS, Beijing (China)], E-mail: wuzy@ihep.ac.cn

    2007-07-15

    Diffraction enhanced imaging (DEI) with two crystals has been performed at the 4W1A beamline at Beijing Synchrotron Radiation Facility (BSRF). Two different crystal geometrical layouts were used to collect images, in the first layout the rotation axis of the crystal has been set perpendicular to the orbital plane while in the second the axis is parallel to the orbital plane. Performance comparison between the two layouts is discussed in terms of thermal expansion of the crystal induced by the heat load, imaging homogeneity, spatial resolution and angular resolution. From both experimental and theoretical data we show that the best images may be obtained with the optical layout in which the rotation axis of the crystals is perpendicular to the orbital plane.

  15. A morphospace for reef fishes: elongation is the dominant axis of body shape evolution.

    Directory of Open Access Journals (Sweden)

    Thomas Claverie

    Full Text Available Tropical reef fishes are widely regarded as being perhaps the most morphologically diverse vertebrate assemblage on earth, yet much remains to be discovered about the scope and patterns of this diversity. We created a morphospace of 2,939 species spanning 56 families of tropical Indo-Pacific reef fishes and established the primary axes of body shape variation, the phylogenetic consistency of these patterns, and whether dominant patterns of shape change can be accomplished by diverse underlying changes. Principal component analysis showed a major axis of shape variation that contrasts deep-bodied species with slender, elongate forms. Furthermore, using custom methods to compare the elongation vector (axis that maximizes elongation deformation and the main vector of shape variation (first principal component for each family in the morphospace, we showed that two thirds of the families diversify along an axis of body elongation. Finally, a comparative analysis using a principal coordinate analysis based on the angles among first principal component vectors of each family shape showed that families accomplish changes in elongation with a wide range of underlying modifications. Some groups such as Pomacentridae and Lethrinidae undergo decreases in body depth with proportional increases in all body regions, while other families show disproportionate changes in the length of the head (e.g., Labridae, the trunk or caudal region in all combinations (e.g., Pempheridae and Pinguipedidae. In conclusion, we found that evolutionary changes in body shape along an axis of elongation dominates diversification in reef fishes. Changes in shape on this axis are thought to have immediate implications for swimming performance, defense from gape limited predators, suction feeding performance and access to some highly specialized habitats. The morphological modifications that underlie changes in elongation are highly diverse, suggesting a role for a range of

  16. A Morphospace for Reef Fishes: Elongation Is the Dominant Axis of Body Shape Evolution

    Science.gov (United States)

    Claverie, Thomas; Wainwright, Peter C.

    2014-01-01

    Tropical reef fishes are widely regarded as being perhaps the most morphologically diverse vertebrate assemblage on earth, yet much remains to be discovered about the scope and patterns of this diversity. We created a morphospace of 2,939 species spanning 56 families of tropical Indo-Pacific reef fishes and established the primary axes of body shape variation, the phylogenetic consistency of these patterns, and whether dominant patterns of shape change can be accomplished by diverse underlying changes. Principal component analysis showed a major axis of shape variation that contrasts deep-bodied species with slender, elongate forms. Furthermore, using custom methods to compare the elongation vector (axis that maximizes elongation deformation) and the main vector of shape variation (first principal component) for each family in the morphospace, we showed that two thirds of the families diversify along an axis of body elongation. Finally, a comparative analysis using a principal coordinate analysis based on the angles among first principal component vectors of each family shape showed that families accomplish changes in elongation with a wide range of underlying modifications. Some groups such as Pomacentridae and Lethrinidae undergo decreases in body depth with proportional increases in all body regions, while other families show disproportionate changes in the length of the head (e.g., Labridae), the trunk or caudal region in all combinations (e.g., Pempheridae and Pinguipedidae). In conclusion, we found that evolutionary changes in body shape along an axis of elongation dominates diversification in reef fishes. Changes in shape on this axis are thought to have immediate implications for swimming performance, defense from gape limited predators, suction feeding performance and access to some highly specialized habitats. The morphological modifications that underlie changes in elongation are highly diverse, suggesting a role for a range of developmental processes

  17. FAMILY HISTORY STUDY OF THE FAMILIAL COAGGREGATION OF BORDERLINE PERSONALITY DISORDER WITH AXIS I AND NON-BORDERLINE DRAMATIC CLUSTER AXIS II DISORDERS

    OpenAIRE

    Zanarini, Mary C.; Barison, Leah K.; Frankenburg, Frances R.; Reich, D. Bradford; Hudson, James I.

    2009-01-01

    The purpose of this study was to assess the familial coaggregation of borderline personality disorder (BPD) with a full array of axis I disorders and four axis II disorders (antisocial personality disorder, histrionic personality disorder, narcissistic personality disorder, and sadistic personality disorder) in the first-degree relatives of borderline probands and axis II comparison subjects. Four hundred and forty-five inpatients were interviewed about familial psychopathology using the Revi...

  18. Two-Channel Metal Detector Using Two Perpendicular Antennas

    Directory of Open Access Journals (Sweden)

    Kyoo Nam Choi

    2014-01-01

    Full Text Available Two-channel metal detector, having two sets of perpendicularly oriented sensor antennas, is proposed to expand detectable size, ranging from mm through cm scale, of metal sensor, while conventional metal sensor is dedicated for detection only in mm or cm scale. The characteristics of the two metal detection sensor channels were investigated, respectively, and the interference effect, while in simultaneous operation, between two sensor channels was discussed. Metal detection channel, having sensitivity in mm scale, showed detectable sensitivity to moving ferrous sphere, with diameter down to 0.7 mm, at 50 kHz exciting frequency and enhanced sensitivity distribution. And metal detection channel having sensitivity in cm scale showed more uniform sensitivity distribution with the flexibility for future modular construction. The effect of interference, while in simultaneous operation of two sensors, resulted in reduced output response, but still within usable detection range. Thus it was feasible to operate two sensors, having different sensitivity range, simultaneously and to extend detection range from mm to cm scale, within practically acceptable interference.

  19. Magnetic field pitch angle and perpendicular velocity measurements from multi-point time-delay estimation of poloidal correlation reflectometry

    Science.gov (United States)

    Prisiazhniuk, D.; Krämer-Flecken, A.; Conway, G. D.; Happel, T.; Lebschy, A.; Manz, P.; Nikolaeva, V.; Stroth, U.; the ASDEX Upgrade Team

    2017-02-01

    In fusion machines, turbulent eddies are expected to be aligned with the direction of the magnetic field lines and to propagate in the perpendicular direction. Time delay measurements of density fluctuations can be used to calculate the magnetic field pitch angle α and perpendicular velocity {{v}\\bot} profiles. The method is applied to poloidal correlation reflectometry installed at ASDEX Upgrade and TEXTOR, which measure density fluctuations from poloidally and toroidally separated antennas. Validation of the method is achieved by comparing the perpendicular velocity (composed of the E× B drift and the phase velocity of turbulence {{v}\\bot}={{v}E× B}+{{v}\\text{ph}} ) with Doppler reflectometry measurements and with neoclassical {{v}E× B} calculations. An important condition for the application of the method is the presence of turbulence with a sufficiently long decorrelation time. It is shown that at the shear layer the decorrelation time is reduced, limiting the application of the method. The magnetic field pitch angle measured by this method shows the expected dependence on the magnetic field, plasma current and radial position. The profile of the pitch angle reproduces the expected shape and values. However, comparison with the equilibrium reconstruction code cliste suggests an additional inclination of turbulent eddies at the pedestal position (2-3°). This additional angle decreases towards the core and at the edge.

  20. Mitochondrial–Lysosomal Axis in Acetaminophen Hepatotoxicity

    Directory of Open Access Journals (Sweden)

    Anna Moles

    2018-05-01

    Full Text Available Acetaminophen (APAP toxicity is the most common cause of acute liver failure and a major indication for liver transplantion in the United States and Europe. Although significant progress has been made in understanding the molecular mechanisms underlying APAP hepatotoxicity, there is still an urgent need to find novel and effective therapies against APAP-induced acute liver failure. Hepatic APAP metabolism results in the production of the reactive metabolite N-acetyl-p-benzoquinone imine (NAPQI, which under physiological conditions is cleared by its conjugation with glutathione (GSH to prevent its targeting to mitochondria. APAP overdose or GSH limitation leads to mitochondrial NAPQI-protein adducts formation, resulting in oxidative stress, mitochondrial dysfunction, and necrotic cell death. As mitochondria are a major target of APAP hepatotoxicity, mitochondrial quality control and clearance of dysfunctional mitochondria through mitophagy, emerges as an important strategy to limit oxidative stress and the engagement of molecular events leading to cell death. Recent evidence has indicated a lysosomal–mitochondrial cross-talk that regulates APAP hepatotoxicity. Moreover, as lysosomal function is essential for mitophagy, impairment in the fusion of lysosomes with autophagosomes-containing mitochondria may compromise the clearance of dysfunctional mitochondria, resulting in exacerbated APAP hepatotoxicity. This review centers on the role of mitochondria in APAP hepatotoxicity and how the mitochondrial/lysosomal axis can influence APAP-induced liver failure.

  1. A study of Ni-based WC composite coatings by laser induction hybrid rapid cladding with elliptical spot

    International Nuclear Information System (INIS)

    Zhou Shengfeng; Huang Yongjun; Zeng Xiaoyan

    2008-01-01

    Ni-based WC composite coatings by laser induction hybrid rapid cladding (LIHRC) with elliptical spot were investigated. Results indicate that the efficiency using the elliptical spot of 6 mm x 4 mm (the major and minor axis of laser beam are 6 mm and 4 mm, respectively, the major axis is parallel to the direction of laser scanning) is higher than that using the elliptical spot of 4 mm x 6 mm (the major axis is perpendicular to the direction of laser scanning). The precipitated carbides with the blocky and bar-like shape indicate that WC particles suffer from the heat damage of 'the disintegration pattern + the growth pattern', whichever elliptical spot is used at low laser scanning speed. However, at high laser scanning speed, the blocky carbides are only formed if the elliptical spot of 6 mm x 4 mm is adopted, showing that WC particles present the heat damage of 'the disintegration pattern', whereas the fine carbides are precipitated when the elliptical spot of 4 mm x 6 mm is used, showing that WC particles take on the heat damage of 'the radiation pattern'. Especially, the efficiency of LIHRC is increased much four times higher than that of the general laser cladding and crack-free ceramic-metal coatings can be obtained

  2. Left ventricular long axis function assessed during cine-cardiovascular magnetic resonance is an independent predictor of adverse cardiac events.

    Science.gov (United States)

    Rangarajan, Vibhav; Chacko, Satish Jacob; Romano, Simone; Jue, Jennifer; Jariwala, Nikhil; Chung, Jaehoon; Farzaneh-Far, Afshin

    2016-06-07

    Left ventricular pump function requires a complex interplay involving myocardial fibers orientated in the longitudinal, oblique and circumferential directions. Long axis dysfunction appears to be an early marker for a number of pathological states. We hypothesized that mitral annular plane systolic excursion (MAPSE) measured during cine-cardiovascular magnetic resonance (CMR) reflects changes in long axis function and may be an early marker for adverse cardiovascular outcomes. The aims of this study were therefore: 1) To assess the feasibility and reproducibility of MAPSE measurements during routine cine-CMR; and 2) To assess whether MAPSE, as a surrogate for long axis function, is a predictor of major adverse cardiovascular events (MACE). Four hundred consecutive patients undergoing CMR were prospectively enrolled. MAPSE was measured in the 4-chamber cine view. Patients were prospectively followed for major adverse cardiac events (MACE) - death, non-fatal myocardial infarction, hospitalization for heart failure or unstable angina, and late revascularization. Cox proportional hazards regression modeling was used to identify factors independently associated with MACE. Net reclassification improvement (NRI) was calculated to assess whether addition of MAPSE resulted in improved risk reclassification of MACE. Seventy-two MACE occurred during a median follow-up of 14.5 months. By Kaplan-Meier analysis, patients with lateral MAPSE cine-CMR is an independent predictor of MACE.

  3. Anomalous Swelling in Wet-Spin Films of Divalent Calf-Thymus DNA

    Science.gov (United States)

    Marlowe, R. L.; Lee, S. A.; Rupprecht, A.

    2004-03-01

    The dimension of wet-spun oriented films of Ca- and MgDNA in the direction perpendicular to the helical axis has been measured using optical microscopy as a function of relative humidity (RH). Earlier work on monovalent DNA films found that the perpendicular dimension increases monotonically with RH. In contrast, both Ca - and MgDNA films display a 15% shrinkage in the perpendicular direction at about 93% RH and expand at higher values of RH.

  4. Ankle-foot orthosis bending axis influences running mechanics.

    Science.gov (United States)

    Russell Esposito, Elizabeth; Ranz, Ellyn C; Schmidtbauer, Kelly A; Neptune, Richard R; Wilken, Jason M

    2017-07-01

    Passive-dynamic ankle-foot orthoses (AFOs) are commonly prescribed to improve locomotion for people with lower limb musculoskeletal weakness. The clinical prescription and design process are typically qualitative and based on observational assessment and experience. Prior work examining the effect of AFO design characteristics generally excludes higher impact activities such as running, providing clinicians and researchers limited information to guide the development of objective prescription guidelines. The proximal location of the bending axis may directly influence energy storage and return and resulting running mechanics. The purpose of this study was to determine if the location of an AFO's bending axis influences running mechanics. Marker and force data were recorded as 12 participants with lower extremity weakness ran overground while wearing a passive-dynamic AFO with posterior struts manufactured with central (middle) and off-centered (high and low) bending axes. Lower extremity joint angles, moments, powers, and ground reaction forces were calculated and compared between limbs and across bending axis conditions. Bending axis produced relatively small but significant changes. Ankle range of motion increased as the bending axis shifted distally (pbenefits during running, although individual preference and physical ability should also be considered. Published by Elsevier B.V.

  5. Self-starting aerodynamics analysis of vertical axis wind turbine

    Directory of Open Access Journals (Sweden)

    Jianyang Zhu

    2015-12-01

    Full Text Available Vertical axis wind turbine is a special type of wind-force electric generator which is capable of working in the complicated wind environment. The self-starting aerodynamics is one of the most important considerations for this kind of turbine. This article aims at providing a systematic synthesis on the self-starting aerodynamic characteristics of vertical axis wind turbine based on the numerical analysis approach. First, the physical model of vertical axis wind turbine and its parameter definitions are presented. Secondary, the interaction model between the vertical axis wind turbine and fluid is developed by using the weak coupling approach; the numerical data of this model are then compared with the wind tunnel experimental data to show its feasibility. Third, the effects of solidity and fixed pitch angle on the self-starting aerodynamic characteristics of the vertical axis wind turbine are analyzed systematically. Finally, the quantification effects of the solidity and fixed pitch angle on the self-starting performance of the turbine can be obtained. The analysis in this study will provide straightforward physical insight into the self-starting aerodynamic characteristics of vertical axis wind turbine.

  6. Design and optimize of 3-axis filament winding machine

    Science.gov (United States)

    Quanjin, Ma; Rejab, M. R. M.; Idris, M. S.; Bachtiar, B.; Siregar, J. P.; Harith, M. N.

    2017-10-01

    Filament winding technique is developed as the primary process for composite cylindrical structures fabrication at low cost. Fibres are wound on a rotating mandrel by a filament winding machine where resin impregnated fibres pass through a pay-out eye. This paper aims to develop and optimize a 3-axis, lightweight, practical, efficient, portable filament winding machine to satisfy the customer demand, which can fabricate pipes and round shape cylinders with resins. There are 3 main units on the 3-axis filament winding machine, which are the rotary unit, the delivery unit and control system unit. Comparison with previous existing filament winding machines in the factory, it has 3 degrees of freedom and can fabricate more complex shape specimens based on the mandrel shape and particular control system. The machine has been designed and fabricated on 3 axes movements with control system. The x-axis is for movement of the carriage, the y-axis is the rotation of mandrel and the z-axis is the movement of the pay-out eye. Cylindrical specimens with different dimensions and winding angles were produced. 3-axis automated filament winding machine has been successfully designed with simple control system.

  7. Off-axis vortex breakdown in a shallow whirlpool.

    Science.gov (United States)

    Herrada, Miguel A; Shtern, Vladimir N; López-Herrera, José María

    2013-06-01

    The off-axis emergence of vortex breakdown (VB) is revealed. The steady axisymmetric flow in a vertical sealed cylinder, which is partially filled with water and the rest is filled with air, is driven by the rotating bottom disk. The numerical simulations show that VB can emerge away from the rotation axis, interface, and walls. As the rotation intensifies, VB first develops in the water region. If the water height is less (larger) than nearly one half of the cylinder radius, VB emerges off (on) the axis. As the rotation further increases, the off-axis VB ring touches the interface and then a thin countercirculation layer develops in the air flow above the water VB domain. This two-fluid VB ring shrinks (it even disappears in a very shallow whirlpool) as the interface approaches the bottom disk.

  8. Thoughts on the so-called 'radius-capitellum axis'

    International Nuclear Information System (INIS)

    Schild, H.; Mueller, H.A.; Wagner, H.; Baetz, W.; Mainz Univ.

    1982-01-01

    We have studied 438 patients radiologically in order to observe the so-called 'radius-capitellum axis'. In about a quarter of people with normal elbows the axis passes lateral to the middle portion of the capitellum, so that even when there is marked deviation, there is no certainty that the humero-radial joint is abnormal. Deviation of the axis can be caused by changes in the shape of the capitellum or of the radius, or by distension of the capsule of the elbow joint, or by various changes in muscular pull. (orig.) [de

  9. Thoughts on the so-called radius-capitellum axis

    Energy Technology Data Exchange (ETDEWEB)

    Schild, H; Mueller, H A; Wagner, H; Baetz, W

    1982-02-01

    We have studied 438 patients radiologically in order to observe the so-called 'radius-capitellum axis'. In about a quarter of people with normal elbows the axis passes lateral to the middle portion of the capitellum, so that even when there is marked deviation, there is no certainty that the humero-radial joint is abnormal. Deviation of the axis can be caused by changes in the shape of the capitellum or of the radius, or by distension of the capsule of the elbow joint, or by various changes in muscular pull.

  10. Atomistic Modeling of Thermal Conductivity of Epoxy Nanotube Composites

    Science.gov (United States)

    Fasanella, Nicholas A.; Sundararaghavan, Veera

    2016-05-01

    The Green-Kubo method was used to investigate the thermal conductivity as a function of temperature for epoxy/single wall carbon nanotube (SWNT) nanocomposites. An epoxy network of DGEBA-DDS was built using the `dendrimer' growth approach, and conductivity was computed by taking into account long-range Coulombic forces via a k-space approach. Thermal conductivity was calculated in the direction perpendicular to, and along the SWNT axis for functionalized and pristine SWNT/epoxy nanocomposites. Inefficient phonon transport at the ends of nanotubes is an important factor in the thermal conductivity of the nanocomposites, and for this reason discontinuous nanotubes were modeled in addition to long nanotubes. The thermal conductivity of the long, pristine SWNT/epoxy system is equivalent to that of an isolated SWNT along its axis, but there was a 27% reduction perpendicular to the nanotube axis. The functionalized, long SWNT/epoxy system had a very large increase in thermal conductivity along the nanotube axis (~700%), as well as the directions perpendicular to the nanotube (64%). The discontinuous nanotubes displayed an increased thermal conductivity along the SWNT axis compared to neat epoxy (103-115% for the pristine SWNT/epoxy, and 91-103% for functionalized SWNT/epoxy system). The functionalized system also showed a 42% improvement perpendicular to the nanotube, while the pristine SWNT/epoxy system had no improvement over epoxy. The thermal conductivity tensor is averaged over all possible orientations to see the effects of randomly orientated nanotubes, and allow for experimental comparison. Excellent agreement is seen for the discontinuous, pristine SWNT/epoxy nanocomposite. These simulations demonstrate there exists a threshold of the SWNT length where the best improvement for a composite system with randomly oriented nanotubes would transition from pristine SWNTs to functionalized SWNTs.

  11. Planar isotropy of passive scalar turbulent mixing with a mean perpendicular gradient.

    Science.gov (United States)

    Danaila, L; Dusek, J; Le Gal, P; Anselmet, F; Brun, C; Pumir, A

    1999-08-01

    A recently proposed evolution equation [Vaienti et al., Physica D 85, 405 (1994)] for the probability density functions (PDF's) of turbulent passive scalar increments obtained under the assumptions of fully three-dimensional homogeneity and isotropy is submitted to validation using direct numerical simulation (DNS) results of the mixing of a passive scalar with a nonzero mean gradient by a homogeneous and isotropic turbulent velocity field. It is shown that this approach leads to a quantitatively correct balance between the different terms of the equation, in a plane perpendicular to the mean gradient, at small scales and at large Péclet number. A weaker assumption of homogeneity and isotropy restricted to the plane normal to the mean gradient is then considered to derive an equation describing the evolution of the PDF's as a function of the spatial scale and the scalar increments. A very good agreement between the theory and the DNS data is obtained at all scales. As a particular case of the theory, we derive a generalized form for the well-known Yaglom equation (the isotropic relation between the second-order moments for temperature increments and the third-order velocity-temperature mixed moments). This approach allows us to determine quantitatively how the integral scale properties influence the properties of mixing throughout the whole range of scales. In the simple configuration considered here, the PDF's of the scalar increments perpendicular to the mean gradient can be theoretically described once the sources of inhomogeneity and anisotropy at large scales are correctly taken into account.

  12. Magneto-Seebeck effect in magnetic tunnel junctions with perpendicular anisotropy

    Directory of Open Access Journals (Sweden)

    Keyu Ning

    2017-01-01

    Full Text Available As one invigorated filed of spin caloritronics combining with spin, charge and heat current, the magneto-Seebeck effect has been experimentally and theoretically studied in spin tunneling thin films and nanostructures. Here we analyze the tunnel magneto-Seebeck effect in magnetic tunnel junctions with perpendicular anisotropy (p-MTJs under various measurement temperatures. The large tunnel magneto-Seebeck (TMS ratio up to −838.8% for p-MTJs at 200 K is achieved, with Seebeck coefficient S in parallel and antiparallel states of 6.7 mV/K and 62.9 mV/K, respectively. The temperature dependence of the tunnel magneto-Seebeck can be attributed to the contributing transmission function and electron states at the interface between CoFeB electrode and MgO barrier.

  13. RAPID COSMIC-RAY ACCELERATION AT PERPENDICULAR SHOCKS IN SUPERNOVA REMNANTS

    Energy Technology Data Exchange (ETDEWEB)

    Takamoto, Makoto; Kirk, John G., E-mail: mtakamoto@eps.s.u-tokyo.ac.jp, E-mail: john.kirk@mpi-hd.mpg.de [Max-Planck-Institut für Kernphysik, Postfach 103980, D-69029 Heidelberg (Germany)

    2015-08-10

    Perpendicular shocks are shown to be rapid particle accelerators that perform optimally when the ratio u{sub s} of the shock speed to the particle speed roughly equals the ratio 1/η of the scattering rate to the gyro frequency. We use analytical methods and Monte-Carlo simulations to solve the kinetic equation that governs the anisotropy generated at these shocks, and find, for ηu{sub s} ≈ 1, that the spectral index softens by unity and the acceleration time increases by a factor of two compared to the standard result of the diffusive shock acceleration theory. These results provide a theoretical basis for the 30 year old conjecture that a supernova exploding into the wind of a Wolf–Rayet star may accelerate protons to an energy exceeding 10{sup 15} eV.

  14. Microwave frequency tuning in heterogeneous spin torque oscillator with perpendicular polarizer: A macrospin study

    Science.gov (United States)

    Bhoomeeswaran, H.; Vivek, T.; Sabareesan, P.

    2018-04-01

    In this article, we have theoretically devised a Spin Torque Nano Oscillator (STNO) with perpendicular polarizer using macro spin model. The devised spin valve structure is heterogeneous (i.e.) it is made of two different ferromagnetic materials [Co and its alloy CoFeB]. The dynamics of magnetization provoked by spin transfer torque is studied numerically by solving the famous Landau-Lifshitz-Gilbert-Slonczewski [LLGS] equation. The results are obtained for the perpendicular polarizer and for that particular out of plane orientation we vary the free layer angle from 10° to 90°. The obtained results are highly appealing, because frequency range is available in all the tilt angles of free layer and it is exceptionally tunable in all free layer tilt angles with zero applied field. Moreover, the utmost operating frequency of about 83.3 GHz and its corresponding power of 4.488 µW/mA2/GHz is acquired for the free layer tilt angle θ = 90° with the solid applied current density of 10 × 1010 A/m2. Also, our device emits high quality factor of about 396, which is remarkably desirable for making devices. These pioneering results provides a significant development for future spintronic based devices.

  15. Three-Axis Ground Reaction Force Distribution during Straight Walking.

    Science.gov (United States)

    Hori, Masataka; Nakai, Akihito; Shimoyama, Isao

    2017-10-24

    We measured the three-axis ground reaction force (GRF) distribution during straight walking. Small three-axis force sensors composed of rubber and sensor chips were fabricated and calibrated. After sensor calibration, 16 force sensors were attached to the left shoe. The three-axis force distribution during straight walking was measured, and the local features of the three-axis force under the sole of the shoe were analyzed. The heel area played a role in receiving the braking force, the base area of the fourth and fifth toes applied little vertical or shear force, the base area of the second and third toes generated a portion of the propulsive force and received a large vertical force, and the base area of the big toe helped move the body's center of mass to the other foot. The results demonstrate that measuring the three-axis GRF distribution is useful for a detailed analysis of bipedal locomotion.

  16. Hysteresis of critical currents of superconducting bridges in low perpendicular magnetic fields

    International Nuclear Information System (INIS)

    Aomine, T.; Tanaka, E.; Yamasaki, S.; Tani, K.; Yonekura, A.

    1989-01-01

    Hysteresis of critical currents I c of superconducting bridges with In, Nb, and NbN has been studied in low perpendicular magnetic fields. Influences of bridge geometry, small field sweep, trapped flux, and bombardment of argon ions on the hysteresis were made clear. The experimental results suggest that the edge pinning and trapped flux in the bank of bridges are associated with the hysteresis. The peak value of I c of NbN bridges, as well as granular Al and In bridges reported before, in decreasing fields agrees with the calculated pair-breaking current. The origin of the hysteresis is discussed

  17. Tilted spin torque-driven ferromagnetic resonance in a perpendicular-analyzer magnetic trilayer

    International Nuclear Information System (INIS)

    Wang Rixing; He Pengbin; Liu Quanhui; Li Zaidong; Pan Anlian; Zou Bingsuo; Wang Yanguo

    2010-01-01

    A theoretical study is presented on the current-driven ferromagnetic resonance in the magnetic trilayers. On the basis of the Landau-Lifshitz-Gilbert-Slonczewski equation, we derive the output dc voltage for arbitrary anisotropy in the free and pinned layers by the linearization method. As an example, the resonance spectra of the tilted-polarizer and perpendicular-analyzer trilayer show that the equilibrium position, the resonant linewidth and the resonant location can be tuned by changing the magnitude and the direction of spin torque. The effective damping can be minimized through adjusting the current and the pinned-layer magnetization direction.

  18. Spin torque switching of 20 nm magnetic tunnel junctions with perpendicular anisotropy

    Science.gov (United States)

    Gajek, M.; Nowak, J. J.; Sun, J. Z.; Trouilloud, P. L.; O'Sullivan, E. J.; Abraham, D. W.; Gaidis, M. C.; Hu, G.; Brown, S.; Zhu, Y.; Robertazzi, R. P.; Gallagher, W. J.; Worledge, D. C.

    2012-03-01

    Spin-transfer torque magnetic random access memory (STT-MRAM) is one of the most promising emerging non-volatile memory technologies. MRAM has so far been demonstrated with a unique combination of density, speed, and non-volatility in a single chip, however, without the capability to replace any single mainstream memory. In this paper, we demonstrate the basic physics of spin torque switching in 20 nm diameter magnetic tunnel junctions with perpendicular magnetic anisotropy materials. This deep scaling capability clearly indicates the STT MRAM device itself may be suitable for integration at much higher densities than previously proven.

  19. Manual input device for controlling a robot arm

    International Nuclear Information System (INIS)

    Fischer, P.J.; Siva, K.V.

    1990-01-01

    A six-axis input device, eg joystick, is supported by a mechanism which enables the joystick to be aligned with any desired orientation, eg parallel to the tool. The mechanism can then be locked to provide a rigid support of the joystick. The mechanism may include three pivotal joints whose axes are perpendicular, each incorporating a clutch. The clutches may be electromagnetic or mechanical and may be operable jointly or independently. The robot arm comprises a base rotatable about a vertical axis, an upper arm, a forearm and a tool or grip rotatable about three perpendicular axes relative to the forearm. (author)

  20. Perpendicular Structure Formation of Block Copolymer Thin Films during Thermal Solvent Vapor Annealing : Solvent and Thickness Effects

    NARCIS (Netherlands)

    Yang, Qiuyan; Loos, Katja

    2017-01-01

    Solvent vapor annealing of block copolymer (BCP) thin films can produce a range of interesting morphologies, especially when the perpendicular orientation of micro-domains with respect to the substrate plays a role. This, for instance, allows BCP thin films to serve as useful templates for

  1. Low energy (e,2e) studies of the noble gases in the perpendicular plane

    OpenAIRE

    Nixon , Kate L; Murray , Andrew James; Kaiser , Christian

    2010-01-01

    Abstract Detailed (e, 2e) studies of the electron impact ionization of the noble gases helium, neon, argon, krypton and xenon have been carried out from near threshold to intermediate energies, where the outgoing electrons carry equal energy from the interaction. The experiments were conducted in the perpendicular plane, where the outgoing electrons are both detected orthogonal to the incident electron beam. For electrons to emerge in this geometry they must undergo multiple scattering, in...

  2. Subcritical-to-supercritical transition in quasi-perpendicular fast shocks

    International Nuclear Information System (INIS)

    Livesey, W.A.

    1985-01-01

    The magnetic structure of collisionless quasi-perpendicular bow shock waves was observed and studied using fluxgate magnetometer data from the ISEE-1 and 2 spacecraft. The angle theta/sub Bn/ between upstream magnetic field and the shock normal was determined for each case. The fast Mach number M, β/sub i/, and β/sub e/ of the shock waves were estimated using solar wind plasma parameters. The critical fast Mach number M/sub c/, the Mach number for which the downstream flow speed just equals the downstream sound speed, was calculated for each shock using the Rankine-Hugoniot shock jump conditions. A survey of the dependence of various magnetic substructures upon these parameters was performed. A precursor foot to the shock was noted for shock waves characterized by M/M/sub c/ > 1. The thickness of this foot region was in good quantitative agreement with predicted trajectories of solar wind ions undergoing specular reflection from the shock ramp

  3. Quasi-perpendicular/quasi-parallel divisions of Earth's bow shock

    International Nuclear Information System (INIS)

    Greenstadt, E.W.

    1991-01-01

    Computer-drawn diagrams of the boundaries between quasi-perpendicular and quasi-parallel areas of Earth's bow shock are displayed for a few selected cone angles of static interplanetary magnetic field (IMF). The effect on the boundary of variable IMF in the foreshock is also discussed and shown for one nominal case. The boundaries demand caution in applying them to the realistic, dynamic conditions of the solar wind and in interpreting the effects of small cone angles on the distributions of structures at the shock. However, the calculated, first-order boundaries are helpful in defining areas of the shock where contributions from active structures inherent in quasi-parallel geometry may be distinguishable from those derived secondarily from upstream reflected ion dynamics. The boundaries are also compatible with known behavior of daytime ULF geomagnetic waves and pulsations according to models postulating that cone angle-controlled, time-dependent ULF activity around the subsolar point of the bow shock provides the source of geomagnetic excitation

  4. Domain wall motion in ferromagnetic systems with perpendicular magnetization

    International Nuclear Information System (INIS)

    Szambolics, H.; Toussaint, J.-Ch.; Marty, A.; Miron, I.M.; Buda-Prejbeanu, L.D.

    2009-01-01

    Although we lack clear experimental evidence, apparently out-of-plane magnetized systems are better suited for spintronic applications than the in-plane magnetized ones, mainly due to the smaller current densities required for achieving domain wall motion. [Co/Pt] multilayers belong to the first category of materials, the out-of-plane magnetization orientation arising from the strong perpendicular magnetocrystalline anisotropy. If the magnetization arranges itself out-of-plane narrow Bloch walls occur. In the present paper, both field and current-driven domain wall motion have been investigated for this system, using micromagnetic simulations. Three types of geometries have been taken into account: bulk, thin film and wire, and for all of them a full comparison is done between the effect of the applied field and injected current. The reduction of the system's dimension induces the decrease of the critical field and the critical current, but it does not influence the domain wall displacement mechanism.

  5. Evaluation of Intrinsic Shear Piezoelectric Coefficient d15 of c-Axis Oriented Pb(Zr,Ti)O3 Films

    Science.gov (United States)

    Kanno, Isaku; Akama, Kenji; Wasa, Kiyotaka; Kotera, Hidetoshi

    2009-09-01

    Piezoelectric shear strain was measured for c-axis oriented epitaxial Pb(Zr,Ti)O3 (PZT) thin films. The PZT films, with a composition near the morphotropic phase boundary (MPB), were epitaxially grown on (001) MgO substrates and then microfabricated into a rectangular shape by wet etching of the films. Lateral electrodes were deposited on both sides of the PZT films, to apply an external electric field perpendicular to the polarization. A sinusoidal input voltage of 100 kHz was applied between the lateral electrodes, and in-plane shear vibration was measured by a laser Doppler vibrometer. In-plane displacement due to shear mode piezoelectric vibration was clearly observed and increased proportionally with the voltage. Finite element method (FEM) analysis was conducted to determine the horizontal electric field in the PZT film, and the piezoelectric coefficient d15 was calculated to be 440×10-12 m/V. The d15 of the PZT film represents the intrinsic shear piezoelectric effect, which is slightly smaller than that of bulk PZT, due to the absence of extrinsic effects such as longitudinal and transverse piezoelectric strain or domain rotation.

  6. T=0 phase diagram and nature of domains in ultrathin ferromagnetic films with perpendicular anisotropy

    International Nuclear Information System (INIS)

    Pighin, Santiago A.; Billoni, Orlando V.; Stariolo, Daniel A.; Cannas, Sergio A.

    2010-01-01

    We present the complete zero temperature phase diagram of a model for ultrathin films with perpendicular anisotropy. The whole parameter space of relevant coupling constants is studied in first order anisotropy approximation. Because the ground state is known to be formed by perpendicular stripes separated by Bloch walls, a standard variational approach is used, complemented with specially designed Monte Carlo simulations. We can distinguish four regimes according to the different nature of striped domains: a high anisotropy Ising regime with sharp domain walls, a saturated stripe regime with thicker walls inside which an in-plane component of the magnetization develops, a narrow canted-like regime, characterized by a sinusoidal variation of both the in-plane and the out of plane magnetization components, which upon further decrease of the anisotropy leads to an in-plane ferromagnetic state via a spin reorientation transition (SRT). The nature of domains and walls are described in some detail together with the variation of domain width with anisotropy, for any value of exchange and dipolar interactions. Our results, although strictly valid at T=0, can be valuable for interpreting data on the evolution of domain width at finite temperature, a still largely open problem.

  7. Tomographic array

    International Nuclear Information System (INIS)

    1976-01-01

    The configuration of a tomographic array in which the object can rotate about its axis is described. The X-ray detector is a cylindrical screen perpendicular to the axis of rotation. The X-ray source has a line-shaped focus coinciding with the axis of rotation. The beam is fan-shaped with one side of this fan lying along the axis of rotation. The detector screen is placed inside an X-ray image multiplier tube

  8. Stress-induced sensitization: the hypothalamic-pituitary-adrenal axis and beyond.

    Science.gov (United States)

    Belda, Xavier; Fuentes, Silvia; Daviu, Nuria; Nadal, Roser; Armario, Antonio

    2015-01-01

    Exposure to certain acute and chronic stressors results in an immediate behavioral and physiological response to the situation followed by a period of days when cross-sensitization to further novel stressors is observed. Cross-sensitization affects to different behavioral and physiological systems, more particularly to the hypothalamus-pituitary-adrenal (HPA) axis. It appears that the nature of the initial (triggering) stressor plays a major role, HPA cross-sensitization being more widely observed with systemic or high-intensity emotional stressors. Less important appears to be the nature of the novel (challenging) stressor, although HPA cross-sensitization is better observed with short duration (5-15 min) challenging stressors. In some studies with acute immune stressors, HPA sensitization appears to develop over time (incubation), but most results indicate a strong initial sensitization that progressively declines over the days. Sensitization can affect other physiological system (i.e. plasma catecholamines, brain monoamines), but it is not a general phenomenon. When studied concurrently, behavioral sensitization appears to persist longer than that of the HPA axis, a finding of interest regarding long-term consequences of traumatic stress. In many cases, behavioral and physiological consequences of prior stress can only be observed following imposition of a new stressor, suggesting long-term latent effects of the initial exposure.

  9. [Kennedy V Axis assessment in an Italian outpatient and inpatient population].

    Science.gov (United States)

    Mundo, Emanuela; Bonalume, Laura; Del Corno, Franco; Madeddu, Fabio; Lang, Margherita

    2010-01-01

    Kennedy Axis V or K Axis acts is an alternative tool to the DSM-IVTR Global Assessment of Functioning (GAF) Scale, that many researchers describe as a scale with poor inter-rater reliability and clinical utility. Unlike the GAF scale, K Axis provides a multidimensional and multiaxial approach to measure personal, social and interpersonal functioning in psychiatric outpatients and inpatients. In this study, we examined K Axis's inter-raters reliability by using it with an Italian clinical population. Clinicians used Kennedy Axis V to assess global functioning among 180 inpatients, in 9 psychiatric services in Lombardia and Piemonte. Patients were divided into 4 different diagnostic groups, according to the DSM-IV-TR criteria. Intraclass correlations between two independent raters's scores reveal high level of interrater reliability for all K Axis scales (0,633 < ICC < 0,813). Highly significant results in the Kruskal-Wallis test demonstrate that the patient diagnosis influence all the scales scores. Significant differences in patients functioning profiles in all K Axis scales, apart from Violence one, were noted between different diagnosis groups. In this study high level of raters agreement was noted, even if K Axis scales were used in different mental health services from different clinicians. K Axis scales provide a useful profile of patient global functioning, in line with the specific pathology.

  10. An integrated magnetics component

    DEFF Research Database (Denmark)

    2013-01-01

    The present invention relates to an integrated magnetics component comprising a magnetically permeable core comprising a base member extending in a horizontal plane and first, second, third and fourth legs protruding substantially perpendicularly from the base member. First, second, third...... and fourth output inductor windings are wound around the first, second, third and fourth legs, respectively. A first input conductor of the integrated magnetics component has a first conductor axis and extends in-between the first, second, third and fourth legs to induce a first magnetic flux through a first...... flux path of the magnetically permeable core. A second input conductor of the integrated magnetics component has a second coil axis extending substantially perpendicularly to the first conductor axis to induce a second magnetic flux through a second flux path of the magnetically permeable core...

  11. Constraints on the scale of toroidal-fusion experiments with application to the design of a helical-axis stellarator

    International Nuclear Information System (INIS)

    Noterdaeme, J.M.

    1983-05-01

    Applying the constraints to the design of a helical axis stellarator we find a limit on the combination of toroidal field, current density and major radius. Another major constraint for this concept is the ability to obtain the plasma physics parameters dictated by similarity considerations. This depends on the heating method used. A minimum scale experiment with 2 periods and no linkage of the toroidal and poloidal coils, would have a major radius of 1.2m, a toroidal field of 3.5T and 2MW of ECRH power (for β = 1% nu 2 = 10)

  12. Influence of inhomogeneous coercivities on media noise in granular perpendicular media investigated by using magnetic force microscopy

    International Nuclear Information System (INIS)

    Bai, J.; Takahoshi, H.; Ito, H.; Rheem, Y.W.; Saito, H.; Ishio, S.

    2004-01-01

    We investigated the influence of the inhomogeneous coercivities on the media noise in a CoPtCr-SiO 2 granular perpendicular magnetic recording medium via ex situ and in situ magnetic force microscopy (MFM) techniques. The ex situ MFM analyses exhibited that transition zigzags contributed to strong magnetic clusters in noise images, and thus resulted in dominant component of the media noise. According to the in situ MFM measurements, it was suggested that an amount of magnetic grains inside a microscopic area reversed like one magnetic ''particle because of strong inter-grain exchange coupling, and that these microscopic areas showed their local magnetic switching behaviors. A mathematic transformation was used to obtain approximately the magnetization distribution in recording layer. And the individual microscopic areas inside recorded bits were compared quasi-quantitatively with those leading large transition zigzags in magnetization switching behaviors. It was indicated that the inhomogeneous coercivities is one of crucial reasons of the medium noise in the perpendicular magnetic recording

  13. Analysis and design of a vertical axis wind turbine

    OpenAIRE

    Goyena Iriso, Joseba

    2011-01-01

    The main objective of this project is to design a new vertical axis wind turbine, specifically one Giromill wind turbine. The project development requires performing a previous study of the vertical axis wind turbines currently development. This study has to be performed before starting to design the wind turbine. Other very important aim is the development of a new vertical axis wind turbine. The after analyses that will result in the final design of the wind turbine will b...

  14. Self-starting aerodynamics analysis of vertical axis wind turbine

    OpenAIRE

    Jianyang Zhu; Hailin Huang; Hao Shen

    2015-01-01

    Vertical axis wind turbine is a special type of wind-force electric generator which is capable of working in the complicated wind environment. The self-starting aerodynamics is one of the most important considerations for this kind of turbine. This article aims at providing a systematic synthesis on the self-starting aerodynamic characteristics of vertical axis wind turbine based on the numerical analysis approach. First, the physical model of vertical axis wind turbine and its parameter defi...

  15. 16 CFR 1211.12 - Requirements for edge sensors.

    Science.gov (United States)

    2010-01-01

    ... Section 1211.12 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER PRODUCT SAFETY ACT... that the axis is perpendicular to the plane of the door. For an edge sensor intended to be used on a... direction perpendicular to the plane of the door. See figure 6. (2) With respect to the test of paragraph (a...

  16. Axi-symmetric models of auroral current systems in Jupiter's magnetosphere with predictions for the Juno mission

    Directory of Open Access Journals (Sweden)

    S. W. H. Cowley

    2008-12-01

    Full Text Available We develop two related models of magnetosphere-ionosphere coupling in the jovian system by combining previous models defined at ionospheric heights with magnetospheric magnetic models that allow system parameters to be extended appropriately into the magnetosphere. The key feature of the combined models is thus that they allow direct connection to be made between observations in the magnetosphere, particularly of the azimuthal field produced by the magnetosphere-ionosphere coupling currents and the plasma angular velocity, and the auroral response in the ionosphere. The two models are intended to reflect typical steady-state sub-corotation conditions in the jovian magnetosphere, and transient super-corotation produced by sudden major solar wind-induced compressions, respectively. The key simplification of the models is that of axi-symmetry of the field, flow, and currents about the magnetic axis, limiting their validity to radial distances within ~30 RJ of the planet, though the magnetic axis is appropriately tilted relative to the planetary spin axis and rotates with the planet. The first exploration of the jovian polar magnetosphere is planned to be undertaken in 2016–2017 during the NASA New Frontiers Juno mission, with observations of the polar field, plasma, and UV emissions as a major goal. Evaluation of the models along Juno planning orbits thus produces predictive results that may aid in science mission planning. It is shown in particular that the low-altitude near-periapsis polar passes will generally occur underneath the corresponding auroral acceleration regions, thus allowing brief examination of the auroral primaries over intervals of ~1–3 min for the main oval and ~10 s for narrower polar arc structures, while the "lagging" field deflections produced by the auroral current systems on these passes will be ~0.1°, associated with azimuthal fields above the ionosphere of a few hundred nT.

  17. Principles of azimuthal correlation measurement of J/psi with charged hadrons

    CERN Multimedia

    Maire, Antonin

    2012-01-01

    Schematic illustration of measurement variables in the azimuthal J/psi-hadron correlation measurement. The z-axis perpendicular to the x-y-plane corresponds to the beam axis in the experiment. The reconstructed e+e- pairs are only identifiable as J/psi mesons on a statistical basis.

  18. Effects of the APC materials on c-axis correlated pinning effects in a-axis oriented Y123/2D APC multilayer films

    International Nuclear Information System (INIS)

    Takamura, M.; Mukaida, M.; Horii, S.; Ichinose, A.; Kita, R.; Namba, M.; Awaji, S.; Watanabe, K.; Matsumoto, K.; Yoshida, Y.; Teranishi, R.; Yamada, K.; Mori, N.

    2009-01-01

    For a-axis oriented and c-axis in-plane aligned YBa 2 Cu 3 O 7-δ /artificial pinning center (Y123/APC) alternately-layered thin films, effects of the APC materials on the multilayer structures are discussed. Pr123, (Y 1-x Pr x )123 and Gd 2 CuO 4 (Gd214) were used as APCs. The multilayer structure was observed for Y123/Pr123 films and Y123/Gd214 films. However, some grains are also grown in the Y123/Gd214 film. For the Y123/Pr123 multilayer film, each Pr123 layer act as two-dimensional APCs (2D APCs) in the magnetic field angular dependences of the critical current density. The growth mechanism of the multilayer structure in the Y123/2D APC films is discussed by a transmission electron microscopy and an atomic force microscope. It is found that two conditions are needed to obtain the c-axis correlated pinning effects by 2D APC in the a-axis oriented and c-axis in-plane aligned Y123/APC multilayer films: the same structure as Y123; Y-free APC materials.

  19. Characteristics of thermally assisted magnetic recording in granular perpendicular media

    International Nuclear Information System (INIS)

    Shiino, Hirotaka; Kawana, Mayumi; Miyashita, Eiichi; Hayashi, Naoto; Watanabe, Sadayuki

    2009-01-01

    The effect of thermally assisted magnetic recording using granular perpendicular media with a single-pole-trimmed head has been investigated. A read/write experiment using a spin stand in which the media were heated by laser irradiation demonstrated that the track average amplitude strongly depends on both the position of the write head relative to the center of the laser spot in the down-track direction and on the laser power. Although the signal-to-noise ratio increased with the coercivity of the media, the increment was small; this is thought to be caused by an increase in the switching field distribution of the media with temperature. Our results suggest that the magnetic constant of the media must be optimized with respect to the temperature of writing in order for high-density thermally assisted magnetic recording to be realized

  20. Off-axis and inline electron holography: Experimental comparison

    International Nuclear Information System (INIS)

    Latychevskaia, Tatiana; Formanek, Petr; Koch, C.T.; Lubk, Axel

    2010-01-01

    Electron holography is a very powerful technique for mapping static electric and magnetic potentials down to atomic resolution. While electron holography is commonly considered synonymous with its off-axis variant in the high energy electron microscopy community, inline electron holography is widely applied in low-energy electron microscopy, where the realization of the off-axis setup is still an experimental challenge. This paper demonstrates that both inline and off-axis holography may be used to recover amplitude and phase shift of the very same object, in our example latex spheres of 90 and 200 nm in diameter, producing very similar results, provided the object does not charge under the electron beam.

  1. Compact, Lightweight Electromagnetic Pump for Liquid Metal

    Science.gov (United States)

    Godfroy, Thomas; Palzin, Kurt

    2010-01-01

    A proposed direct-current electromagnetic pump for circulating a molten alkali metal alloy would be smaller and lighter and would demand less input power, relative to currently available pumps of this type. (Molten alkali metals are used as heat-transfer fluids in high-temperature stages of some nuclear reactors.) The principle of operation of this or any such pump involves exploitation of the electrical conductivity of the molten metal: An electric current is made to pass through the liquid metal along an axis perpendicular to the longitudinal axis of the flow channel, and a magnetic field perpendicular to both the longitudinal axis and the electric current is superimposed on the flowchannel region containing the electric current. The interaction between the electric current and the magnetic field produces the pumping force along the longitudinal axis. The advantages of the proposed pump over other such pumps would accrue from design features that address overlapping thermal and magnetic issues.

  2. Phosphorene-directed self-assembly of asymmetric PS-b-PMMA block copolymer for perpendicularly-oriented sub-10 nm PS nanopore arrays

    Science.gov (United States)

    Zhang, Ziming; Zheng, Lu; Khurram, Muhammad; Yan, Qingfeng

    2017-10-01

    Few-layer black phosphorus, also known as phosphorene, is a new two-dimensional material which is of enormous interest for applications, mainly in electronics and optoelectronics. Herein, we for the first time employ phosphorene for directing the self-assembly of asymmetric polystyrene-block-polymethylmethacrylate (PS-b-PMMA) block copolymer (BCP) thin film to form the perpendicular orientation of sub-10 nm PS nanopore arrays in a hexagonal fashion normal to the interface. We experimentally demonstrate that none of the PS and PMMA blocks exhibit preferential affinity to the phosphorene-modified surface. Furthermore, the perpendicularly-oriented PS nanostructures almost stay unchanged with the variation of number of layers of few-layer phosphorene nanoflakes between 15-30 layers. Differing from the neutral polymer brushes which are widely used for chemical modification of the silicon substrate, phosphorene provides a novel physical way to control the interfacial interactions between the asymmetric PS-b-PMMA BCP thin film and the silicon substrate. Based on our results, it is possible to build a new scheme for producing sub-10 nm PS nanopore arrays oriented perpendicularly to the few-layer phosphorene nanoflakes. Furthermore, the nanostructural microdomains could serve as a promising nanolithography template for surface patterning of phosphorene nanoflakes.

  3. Phosphorene-directed self-assembly of asymmetric PS-b-PMMA block copolymer for perpendicularly-oriented sub-10 nm PS nanopore arrays.

    Science.gov (United States)

    Zhang, Ziming; Zheng, Lu; Khurram, Muhammad; Yan, Qingfeng

    2017-10-20

    Few-layer black phosphorus, also known as phosphorene, is a new two-dimensional material which is of enormous interest for applications, mainly in electronics and optoelectronics. Herein, we for the first time employ phosphorene for directing the self-assembly of asymmetric polystyrene-block-polymethylmethacrylate (PS-b-PMMA) block copolymer (BCP) thin film to form the perpendicular orientation of sub-10 nm PS nanopore arrays in a hexagonal fashion normal to the interface. We experimentally demonstrate that none of the PS and PMMA blocks exhibit preferential affinity to the phosphorene-modified surface. Furthermore, the perpendicularly-oriented PS nanostructures almost stay unchanged with the variation of number of layers of few-layer phosphorene nanoflakes between 15-30 layers. Differing from the neutral polymer brushes which are widely used for chemical modification of the silicon substrate, phosphorene provides a novel physical way to control the interfacial interactions between the asymmetric PS-b-PMMA BCP thin film and the silicon substrate. Based on our results, it is possible to build a new scheme for producing sub-10 nm PS nanopore arrays oriented perpendicularly to the few-layer phosphorene nanoflakes. Furthermore, the nanostructural microdomains could serve as a promising nanolithography template for surface patterning of phosphorene nanoflakes.

  4. Experimental hyperthyroidism and central mediators of stress axis and thyroid axis activity in common carp (Cyprinus carpio L.).

    Science.gov (United States)

    Geven, Edwin J W; Verkaar, Folkert; Flik, Gert; Klaren, Peter H M

    2006-12-01

    The effect of experimental hyperthyroidism, realized by T(4) injection, on central mediators of the hypothalamo-pituitary-interrenal axis (HPI-axis) in common carp (Cyprinus carpio L.) was studied. Our results show that hyperthyroidism evokes a marked 3.2-fold reduction in basal plasma cortisol levels. Corticotropin-releasing hormone-binding protein (CRH-BP) mRNA levels in the hypothalamus, measured by real-time quantitative PCR, were significantly elevated by 40%, but CRH, urotensin-I, prepro-TRH, prohormone convertase-1 (PC1), and POMC mRNA levels were unchanged. In the pituitary pars distalis, PC1, CRH receptor-1, and POMC mRNA levels were unaffected, as was ACTH content. Plasma alpha-MSH concentrations were significantly elevated by 30% in hyperthyroid fish, and this was reflected in PC1 and POMC mRNA levels in pituitary pars intermedia that were increased 1.5- and 2.4-fold respectively. The alpha-MSH content of the pars intermedia was unchanged. Hyperthyroidism has profound effects on the basal levels of a central mediator, i.e., CRH-BP, of HPI-axis function in unstressed carp in vivo, and we conclude that HPI- and hypothalamo-pituitary-thyroid-axis functions are strongly interrelated. We suggest that the changes in plasma cortisol, thyroid hormone, and alpha-MSH levels reflect their concerted actions on energy metabolism.

  5. Perpendicular magnetic anisotropy in Co2FeAl0.5Si0.5/MgO bottom electrodes for magnetic tunnel junctions

    International Nuclear Information System (INIS)

    Li, X.Q.; Wu, Y.; Gao, S.; Xu, X.G.; Miao, J.; Jiang, Y.

    2013-01-01

    Perpendicular magnetic anisotropy (PMA) was achieved in annealed Co 2 FeAl 0.5 Si 0.5 (CFAS)/MgO-based multilayers with good thermal stability up to 400 °C and a large anisotropy energy density K u over 2.0 × 10 5 J/m 3 . The thickness of the full-Heusler CFAS film to maintain PMA is up to 4.8 nm in which the co-existence of disordered A2, ordered B2 and fully ordered L2 1 structures is observed. X-ray photoelectron spectroscopy analysis demonstrates that the origin of the PMA is the hybridization between Co 3d and O 2p orbitals at the CFAS/MgO interface. - Highlights: • We achieved perpendicular magnetic anisotropy (PMA) in Co 2 FeAl 0.5 Si 0.5 (4.8 nm) film; • L2 1 , B2 and A2 phases coexist in perpendicular magnetic anisotropic Co 2 FeAl 0.5 Si 0.5 ; • Magnetic properties have strong dependence on the annealing temperature; • The PMA is induced by the hybridization between Co-3d and O-2p orbitals

  6. First-principles investigation of the very large perpendicular magnetic anisotropy at Fe | MgO and Co | MgO interfaces

    KAUST Repository

    Yang, H. X.; Chshiev, M.; Dieny, B.; Lee, J. H.; Manchon, Aurelien; Shin, K. H.

    2011-01-01

    The perpendicular magnetic anisotropy (PMA) arising at the interface between ferromagnetic transition metals and metallic oxides was investigated via first-principles calculations. In this work very large values of PMA, up to 3 erg/cm2, at Fe|MgO interfaces are reported, in agreement with recent experiments. The origin of PMA is attributed to overlap between O-pz and transition metal dz2 orbitals hybridized with dxz(yz) orbitals with stronger spin-orbit coupling-induced splitting around the Fermi level for perpendicular magnetization orientation. Furthermore, it is shown that the PMA value weakens in the case of over- or underoxidation due to the fact that oxygen pz and transition metal dz2 orbital overlap is strongly affected by disorder, in agreement with experimental observations in magnetic tunnel junctions.

  7. First-principles investigation of the very large perpendicular magnetic anisotropy at Fe | MgO and Co | MgO interfaces

    KAUST Repository

    Yang, H. X.

    2011-08-01

    The perpendicular magnetic anisotropy (PMA) arising at the interface between ferromagnetic transition metals and metallic oxides was investigated via first-principles calculations. In this work very large values of PMA, up to 3 erg/cm2, at Fe|MgO interfaces are reported, in agreement with recent experiments. The origin of PMA is attributed to overlap between O-pz and transition metal dz2 orbitals hybridized with dxz(yz) orbitals with stronger spin-orbit coupling-induced splitting around the Fermi level for perpendicular magnetization orientation. Furthermore, it is shown that the PMA value weakens in the case of over- or underoxidation due to the fact that oxygen pz and transition metal dz2 orbital overlap is strongly affected by disorder, in agreement with experimental observations in magnetic tunnel junctions.

  8. A Simple Size Effect Model for Tension Perpendicular to the Grain

    DEFF Research Database (Denmark)

    Pedersen, M. U.; Clorius, Christian Odin; Damkilde, Lars

    2003-01-01

    The strength in tension perpendicular to the grain is known to decrease with an increase in the stressed volume. Usually this size effect is explained on a stochastic basis, that is, an explanation relying on the increased probability of encountering a strength reducing flaw when the volume...... of the material under stress is increased. This paper presents an experimental investigation on specimens with a well-defined structural orientation of the material. The experiments exhibit a large size effect and the nature of the failures encountered suggests that the size effect can be explained...... on a deterministic basis. Arguments for such a simple deterministic explanation of size effect is found in finite element modelling, using the orthotropic stiffness characteristics in the transverse plane of wood....

  9. One-dimensional model of oxygen transport impedance accounting for convection perpendicular to the electrode

    Energy Technology Data Exchange (ETDEWEB)

    Mainka, J. [Laboratorio Nacional de Computacao Cientifica (LNCC), CMC 6097, Av. Getulio Vargas 333, 25651-075 Petropolis, RJ, Caixa Postal 95113 (Brazil); Maranzana, G.; Thomas, A.; Dillet, J.; Didierjean, S.; Lottin, O. [Laboratoire d' Energetique et de Mecanique Theorique et Appliquee (LEMTA), Universite de Lorraine, 2, avenue de la Foret de Haye, 54504 Vandoeuvre-les-Nancy (France); LEMTA, CNRS, 2, avenue de la Foret de Haye, 54504 Vandoeuvre-les-Nancy (France)

    2012-10-15

    A one-dimensional (1D) model of oxygen transport in the diffusion media of proton exchange membrane fuel cells (PEMFC) is presented, which considers convection perpendicular to the electrode in addition to diffusion. The resulting analytical expression of the convecto-diffusive impedance is obtained using a convection-diffusion equation instead of a diffusion equation in the case of classical Warburg impedance. The main hypothesis of the model is that the convective flux is generated by the evacuation of water produced at the cathode which flows through the porous media in vapor phase. This allows the expression of the convective flux velocity as a function of the current density and of the water transport coefficient {alpha} (the fraction of water being evacuated at the cathode outlet). The resulting 1D oxygen transport impedance neglects processes occurring in the direction parallel to the electrode that could have a significant impact on the cell impedance, like gas consumption or concentration oscillations induced by the measuring signal. However, it enables us to estimate the impact of convection perpendicular to the electrode on PEMFC impedance spectra and to determine in which conditions the approximation of a purely diffusive oxygen transport is valid. Experimental observations confirm the numerical results. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Plantar tendons of the foot: MR imaging and US.

    Science.gov (United States)

    Donovan, Andrea; Rosenberg, Zehava Sadka; Bencardino, Jenny T; Velez, Zoraida Restrepo; Blonder, David B; Ciavarra, Gina A; Adler, Ronald Steven

    2013-01-01

    Tendon disorders along the plantar aspect of the foot may lead to significant symptoms but are often clinically misdiagnosed. Familiarity with the normal anatomy of the plantar tendons and its appearance at magnetic resonance (MR) imaging and ultrasonography (US) is essential for recognizing plantar tendon disorders. At MR imaging, the course of the plantar tendons is optimally visualized with dedicated imaging of the midfoot and forefoot. This imaging should include short-axis images obtained perpendicular to the long axis of the metatarsal shafts, which allows true cross-sectional evaluation of the plantar tendons. Normal plantar tendons appear as low-signal-intensity structures with all MR sequences. At US, accurate evaluation of the tendons requires that the ultrasound beam be perpendicular to the tendon. The normal tendon appears as a compact linear band of echogenic tissue that contains a fine, mixed hypoechoic and hyperechoic internal fibrillar pattern. Tendon injuries can be grouped into six major categories: tendinosis, peritendinosis, tenosynovitis, entrapment, rupture, and instability (subluxation or dislocation) and can be well assessed with both MR imaging and US. The radiologist plays an important role in the diagnosis of plantar tendon disorders, and recognizing their imaging appearances at MR imaging and US is essential.

  11. Angular momentum projection of tilted axis rotating states

    Energy Technology Data Exchange (ETDEWEB)

    Oi, M; Onishi, N; Tajima, N [Tokyo Univ. (Japan); Horibata, T

    1998-03-01

    We applied an exact angular momentum projection to three dimensional cranked HFB (3d-CHFB) states. Tilted axis rotating states (TAR) and principal axis rotating states (PAR) are compared. It is shown that TAR is more adequate than PAR for description of the back bending phenomena driven by tilted rotation or wobbling motion. (author)

  12. UARS PEM Level 2 AXIS 2 V001 (UARPE2AXIS2) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The UARS Particle Environment Monitor (PEM) level 2 Atmosphere X-Ray Imaging Spectrometer (AXIS) unit 2 daily product contains the X-ray high-resolution spectral...

  13. UARS PEM Level 2 AXIS 1 V001 (UARPE2AXIS1) at GES DISC

    Data.gov (United States)

    National Aeronautics and Space Administration — The UARS Particle Environment Monitor (PEM) level 2 Atmosphere X-Ray Imaging Spectrometer (AXIS) unit 1 daily product contains the X-ray high-resolution spectral...

  14. Phytochemicals for taming agitated immune-endocrine-neural axis.

    Science.gov (United States)

    Patel, Seema

    2017-07-01

    Homeostasis of immune-endocrine-neural axis is paramount for human health. If this axis gets agitated due to age, genetic variations, environmental exposures or lifestyle assaults, a cascade of adverse reactions occurs in human body. Cytokines, hormones and neurotransmitters, the effector molecules of this axis behave erratically, leading to a gamut of neural, endocrine, autoimmune, and metabolic diseases. Current panel of drugs can tackle some of them but not in a sustainable, benign way as a myriad of side effects, causal of them have been documented. In this context, phytochemicals, the secondary metabolites of plants seem beneficial. These bioactive constituents encompassing polyphenols, alkaloids, flavonoids, terpenoids, tannins, lignans, stilbenoids (resveratrol), saponins, polysaccharides, glycosides, and lectins etc. have been proven to exert antioxidant, anti-inflammatory, hypolipidemic, hypotensive, antidiabetic, anticancer, immunomodulatory, anti-allergic, analgesic, hepatoprotective, neuroprotective, dermatoprotective, and antimicrobial properties, among a litany of other biological effects. This review presents a holistic perspective of common afflictions resultant of immune-endocrine-neural axis disruption, and the phytochemicals capable of restoring their normalcy and mitigating the ailments. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  15. Modal Parameter Identification of New Design of Vertical Axis Wind Turbine

    DEFF Research Database (Denmark)

    Chougule, Prasad; Nielsen, Søren R.K.

    2013-01-01

    Vertical axis wind turbines have lower power efficiency than the horizontal axis wind turbines. However vertical axis wind turbines are proven to be economical and noise free on smaller scale. A new design of three bladed vertical axis wind turbine by using two airfoils in construction of each...... blade has been proposed to improve power efficiency. The purpose of two airfoils in blade design of vertical axis wind turbine is to create high lift which in turns gives higher power output. In such case the structural parameter identification is important to understand the system behavior due to its...... first kind of design before experimental analysis. Therefore a study is carried out to determine the natural frequency to avoid unstable state of the system due to rotational frequency of rotor. The present paper outlines a conceptual design of vertical axis wind turbine and a modal analysis by using...

  16. Neurobiology of Major Depressive Disorder

    Directory of Open Access Journals (Sweden)

    Rosa Villanueva

    2013-01-01

    Full Text Available We survey studies which relate abnormal neurogenesis to major depressive disorder. Clinically, descriptive gene and protein expression analysis and genetic and functional studies revised here show that individual alterations of a complex signaling network, which includes the hypothalamic-pituitary-adrenal axis; the production of neurotrophins and growth factors; the expression of miRNAs; the production of proinflammatory cytokines; and, even, the abnormal delivery of gastrointestinal signaling peptides, are able to induce major mood alterations. Furthermore, all of these factors modulate neurogenesis in brain regions involved in MDD, and are functionally interconnected in such a fashion that initial alteration in one of them results in abnormalities in the others. We highlight data of potential diagnostic significance and the relevance of this information to develop new therapeutic approaches. Controversial issues, such as whether neurogenesis is the basis of the disease or whether it is a response induced by antidepressant treatments, are also discussed.

  17. The Microbiome-Gut-Behavior Axis: Crosstalk Between the Gut Microbiome and Oligodendrocytes Modulates Behavioral Responses.

    Science.gov (United States)

    Ntranos, Achilles; Casaccia, Patrizia

    2018-01-01

    Environmental and dietary stimuli have always been implicated in brain development and behavioral responses. The gut, being the major portal of communication with the external environment, has recently been brought to the forefront of this interaction with the establishment of a gut-brain axis in health and disease. Moreover, recent breakthroughs in germ-free and antibiotic-treated mice have demonstrated the significant impact of the microbiome in modulating behavioral responses in mice and have established a more specific microbiome-gut-behavior axis. One of the mechanisms by which this axis affects social behavior is by regulating myelination at the prefrontal cortex, an important site for complex cognitive behavior planning and decision-making. The prefrontal cortex exhibits late myelination of its axonal projections that could extend into the third decade of life in humans, which make it susceptible to external influences, such as microbial metabolites. Changes in the gut microbiome were shown to alter the composition of the microbial metabolome affecting highly permeable bioactive compounds, such as p-cresol, which could impair oligodendrocyte differentiation. Dysregulated myelination in the prefrontal cortex is then able to affect behavioral responses in mice, shifting them towards social isolation. The reduced social interactions could then limit microbial exchange, which could otherwise pose a threat to the survival of the existing microbial community in the host and, thus, provide an evolutionary advantage to the specific microbial community. In this review, we will analyze the microbiome-gut-behavior axis, describe the interactions between the gut microbiome and oligodendrocytes and highlight their role in the modulation of social behavior.

  18. Subquadratic medial-axis approximation in $\\mathbb{R}^3$

    Directory of Open Access Journals (Sweden)

    Christian Scheffer

    2015-09-01

    Full Text Available We present an algorithm that approximates the medial axis of a smooth manifold in $\\mathbb{R}^3$ which is given by a sufficiently dense point sample. The resulting, non-discrete approximation is shown to converge to the medial axis as the sampling density approaches infinity. While all previous algorithms guaranteeing convergence have a running time quadratic in the size $n$ of the point sample, we achieve a running time of at most $\\mathcal{O}(n\\log^3 n$. While there is no subquadratic upper bound on the output complexity of previous algorithms for non-discrete medial axis approximation, the output of our algorithm is guaranteed to be of linear size.

  19. Postnatal development of the atlas and axis: CT study

    International Nuclear Information System (INIS)

    Byun, Sung Su; Kim, Hyung Jin; Lim, Myung Kwan; Kim, Won Hong; Jeon, Yong Sun; Kim, Jeong Ho; Kim, Sung Tae

    2003-01-01

    To evaluate normal postnatal development of the atlas and axis by means of CT scanning. We prospectively analyzed CT scans of the developing atlas and axis of 200 normal children aged less than 14, investigating the CT appearance of these regions with particular attenuation to two synchondroses related to the atlas and four synchondroses and one ossification center related to the axis. Fusion varying was categorized as either low (grade1-5) or high (grade4-5), according to the varying degrees of fusion at each synchondrosis of ossification center. Neurocentral synchondrosis of the atlas was low grade in all children less than five, and high grade in all aged nine or more, while posterior synchondrosis of the atlas was low grade in 97% of children less than three and high grade in 99% aged three or more. As for the axis, neurocentral synchondrosis was low grade in all children less than three, and high grade in 97% of children aged five or more. PS of the axis was low grade in both children less than 6 months, and high grade in all aged two years or more. Dentocentral synchondrosis of the axis was low grade in 93% of children less than three and high grade in 96% of those aged at least five. Intradental axial synchondrosis was high grade in all children. Fusion of the terminal ossicle with the remainder of the dens was low in all children less than five and high in 97% of those aged nine of more. CT can help determine the parameters of normal postnatal development of the atlas and axis. A knowledge of normal ossification patterns of these regions may help provide an understanding of developmental anomalies and also help prevent confusion with fractures

  20. Design and construction of a triple-axis crystal neutron spectrometer and performance testing by means of measurements of dispersion relations in copper

    International Nuclear Information System (INIS)

    Fuhrmann, C.

    1979-01-01

    The Triple-Axis Crystal Neutron Spectrometer is the best instrument for the study of lattice dynamics, when the neutron inelastic scattering technique is used. Design, construction and operation of a triple-axis crystal neutron spectrometer, whose construction was recently finished at IEA are described. The design principles employed are directed to mechanical simplicity, facility of construction and flexibility in operation, with no adapted components to industrial applications were used in the construction. The operational characteristics of the spectrometer, such as the neutron wavelenght of the incoming beam and the resolution have been determined. With the purpose to check the performance of IEA Triple-Axis Crystal Neutron Spectrometer, dispersion relation curves for copper, at room temperature, have been measured. The frequency of phonons propagating along three major symmetry directions have been determined. The measurements were carried out operating the Triple-Axis Spectrometer in the 'sup(→)Q-constant' mode. An excelent agreement could be observed between the results obtained in the present experiment and the data for copper presented in the literature. This comparison indicates that the IEA Triple-Axis Crystal Neutron Spectrometer is in good operational conditions and is able to perform original experiments. Details on the experimental procedures for the case of a Triple-Axis Spectrometer operating in 'sup(→)Q-constant' mode are also presented. (Author) [pt

  1. Adversity-driven changes in hypothalamic-pituitary-adrenal axis functioning during adolescence

    NARCIS (Netherlands)

    Laceulle, O.M.; Nederhof, Esther; van Aken, M.A.G.; Ormel, Johan

    2017-01-01

    The hypothalamic-pituitary-adrenal (HPA) axis has been proposed to be a key mechanism underlying the link between adversity and mental health, but longitudinal studies on adversity and HPA-axis functioning are scarce. Here, we studied adversity-driven changes in HPA-axis functioning during

  2. Observations of large-amplitude MHD waves in Jupiter's foreshock in connection with a quasi-perpendicular shock structure

    Science.gov (United States)

    Bavassano-Cattaneo, M. B.; Moreno, G.; Scotto, M. T.; Acuna, M.

    1987-01-01

    Plasma and magnetic field observations performed onboard the Voyager 2 spacecraft have been used to investigate Jupiter's foreshock. Large-amplitude waves have been detected in association with the quasi-perpendicular structure of the Jovian bow shock, thus proving that the upstream turbulence is not a characteristic signature of the quasi-parallel shock.

  3. Magnetic Field Control of Cycloidal Domains and Electric Polarization in Multiferroic BiFeO3

    Science.gov (United States)

    Bordács, S.; Farkas, D. G.; White, J. S.; Cubitt, R.; DeBeer-Schmitt, L.; Ito, T.; Kézsmárki, I.

    2018-04-01

    The magnetic field induced rearrangement of the cycloidal spin structure in ferroelectric monodomain single crystals of the room-temperature multiferroic BiFeO3 is studied using small-angle neutron scattering. The cycloid propagation vectors are observed to rotate when magnetic fields applied perpendicular to the rhombohedral (polar) axis exceed a pinning threshold value of ˜5 T . In light of these experimental results, a phenomenological model is proposed that captures the rearrangement of the cycloidal domains, and we revisit the microscopic origin of the magnetoelectric effect. A new coupling between the magnetic anisotropy and the polarization is proposed that explains the recently discovered magnetoelectric polarization perpendicular to the rhombohedral axis.

  4. Properties of a Bound Polaron under a Perpendicular Magnetic Field

    International Nuclear Information System (INIS)

    Liu Jia; Chen Ziyu; Xiao Jinglin; Huo Shufen

    2007-01-01

    We investigate the influence of a perpendicular magnetic field on a bound polaron near the interface of a polar-polar semiconductor with Rashba effect. The external magnetic field strongly changes the ground state binding energy of the polaron and the Rashba spin-orbit (SO) interaction originating from the inversion asymmetry in the heterostructure splits the ground state binding energy of the bound polaron. In this paper, we have shown how the ground state binding energy will be with the change of the external magnetic field, the location of a single impurity, the wave vector of the electron and the electron areal density, taking into account the SO coupling. Due to the presence of the phonons, whose energy gives negative contribution to the polaron's, the spin-splitting states of the bound polaron are more stable, and we find that in the condition of week magnetic field, the Zeeaman effect can be neglected.

  5. General versus gender-specific attributes of the psychology major.

    Science.gov (United States)

    McCray, Jason A; King, Alan R; Bailly, Matthew D

    2005-04-01

    In the present study, the authors extended the search for general and gender-specific factors associated with the selection of psychology as a college major by using the Family Environment Scale (FES; R. H. Moos & B. S. Moos, 1994) and Coolidge Axis II Inventory (CATI; F. L. Coolidge & M. M. Merwin, 1992). The findings were restricted to one general (Schizoid) and one gender-specific (Self-Defeating) set of personality traits that seemed to be associated with the selection of a college major. The intuitive role of many presumed gender-specific factors (e.g., women are more open to discussing personal problems with others) may prove difficult to establish empirically.

  6. Symmetry breaking of adjacent tracks in perpendicular recording system

    International Nuclear Information System (INIS)

    Xie Huang; Wei Dan

    2007-01-01

    The track density increase in a perpendicular magnetic recording system is limited by the adjacent-track interference (ATI). In this work, a composite micromagnetic simulation model of the read/write process is developed to analyse ATI by the symmetry of signal and noise in two adjacent W = 60 nm tracks with the track pitch of the order of 100 nm. Based on the two-dimensional medium noise distribution of dibit recording, it is found that the noise in the first and later recorded tracks start to be asymmetric when the track pitch is lower than 2 W; if the read width is limited within 2/3 of the write width, the asymmetry of noise appears when the track pitch is less than 1.5 W. At higher recording densities, the signal-to-noise ratio degradation is mainly due to the noise caused by the interference from the signal of the adjacent track. Side writing can be effectively eliminated by the use of a guard band whose width is at least half the track width

  7. Tunnel Junction with Perpendicular Magnetic Anisotropy: Status and Challenges

    Directory of Open Access Journals (Sweden)

    Mengxing Wang

    2015-08-01

    Full Text Available Magnetic tunnel junction (MTJ, which arises from emerging spintronics, has the potential to become the basic component of novel memory, logic circuits, and other applications. Particularly since the first demonstration of current induced magnetization switching in MTJ, spin transfer torque magnetic random access memory (STT-MRAM has sparked a huge interest thanks to its non-volatility, fast access speed, and infinite endurance. However, along with the advanced nodes scaling, MTJ with in-plane magnetic anisotropy suffers from modest thermal stability, high power consumption, and manufactural challenges. To address these concerns, focus of research has converted to the preferable perpendicular magnetic anisotropy (PMA based MTJ, whereas a number of conditions still have to be met before its practical application. This paper overviews the principles of PMA and STT, where relevant issues are preliminarily discussed. Centering on the interfacial PMA in CoFeB/MgO system, we present the fundamentals and latest progress in the engineering, material, and structural points of view. The last part illustrates potential investigations and applications with regard to MTJ with interfacial PMA.

  8. Influence of trees on the dispersion of pollutants in an urban street canyon - experimental investigation of the flow and concentration field

    NARCIS (Netherlands)

    Gromke, C.B.; Ruck, B.

    2007-01-01

    Flow field and concentration measurements have been performed in an idealized model of an urban street canyon with one row of trees arranged along the center axis. The model was set up in an atmospheric boundary layer wind tunnel and the approach flow was directed perpendicular to the street axis. A

  9. RITA: The reinvented triple axis spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Mason, T.E. [Toronto Univ., ON (Canada). Dept. of Physics; Clausen, K.N.; Aeppli, G.; McMorrow, D.R.; Kjems, J.K. [Risoe National Lab., Roskilde (Denmark)

    1995-11-01

    Risoe National Laboratory was reported to be in the process of developing a new spectrometer design, RITA, based on the triple axis design. The spectrometer will attempt to incorporate more recent innovations such as multilayer supermirrors and microstrip proportional counters into a rethinking of the triple-axis spectrometer. By optimizing the beam optics, using supermirrors and extending the analyser to map regions of (Q, {omega}) space using an array of independently controllable pyrolytic graphite crystals focussed on an area detector, it was hoped that the efficiency of single-crystal inelastic experiments could be increased by as much as a factor of 20. 7 figs., 20 refs.

  10. Equilibrium studies of helical axis stellarators

    International Nuclear Information System (INIS)

    Hender, T.C.; Carreras, B.A.; Garcia, L.; Harris, J.H.; Rome, J.A.; Cantrell, J.L.; Lynch, V.E.

    1984-01-01

    The equilibrium properties of helical axis stellarators are studied with a 3-D equilibrium code and with an average method (2-D). The helical axis ATF is shown to have a toroidally dominated equilibrium shift and good equilibria up to at least 10% peak beta. Low aspect ratio heliacs, with relatively large toroidal shifts, are shown to have low equilibrium beta limits (approx. 5%). Increasing the aspect ratio and number of field periods proportionally is found to improve the equilibrium beta limit. Alternatively, increasing the number of field periods at fixed aspect ratio which raises and lowers the toroidal shift improves the equilibrium beta limit

  11. Perpendicular magnetic anisotropy in Mo/Co2FeAl0.5Si0.5/MgO/Mo multilayers with optimal Mo buffer layer thickness

    Science.gov (United States)

    Saravanan, L.; Raja, M. Manivel; Prabhu, D.; Pandiyarasan, V.; Ikeda, H.; Therese, H. A.

    2018-05-01

    Perpendicular Magnetic Anisotropy (PMA) was realized in as-deposited Mo(10)/Co2FeAl0.5Si0.5(CFAS)(3)/MgO(0.5)/Mo multilayer stacks with large perpendicular magnetic anisotropy energy (Keff). PMA of this multilayer is found to be strongly dependent on the thickness of the individual CFAS (tCFAS), Mo (tMo) and MgO (tMgO) layers and annealing temperatures. The interactions at the Mo/CFAS/MgO interfaces are critical to induce PMA and are tuned by the interfacial oxidation. The major contribution to PMA is due to iron oxide at the CFAS/MgO interface. X-ray diffraction (XRD) and infrared spectroscopic (FT-IR) studies further ascertain this. However, an adequate oxidation of MgO and the formation of (0 2 4) and (0 1 8) planes of α-Fe2O3 at the optimal Mo buffer layer thickness is mainly inducing PMA in Mo/CFAS/MgO/Mo stack. Microstructural changes in the films are observed by atomic force microscopy (AFM). X-ray photoelectron spectroscopy (XPS) demonstrates the oxidation of CFAS/MgO interface and the formation of Fe-O bonds confirming that the real origin of PMA in Mo/CFAS/MgO is due to hybridization of Fe (3dz2) and O (2pz) orbitals and the resulted spin-orbit interaction at their interface. The half-metallic nature CFAS with Mo layer exhibiting PMA can be a potential candidate as p-MTJs electrodes for the new generation spintronic devices.

  12. Selection for growth rate and body size have altered the expression profiles of somatotropic axis genes in chickens

    Science.gov (United States)

    Liu, Yong; Xu, Zhiqiang; Duan, Xiaohua; Li, Qihua; Dou, Tengfei; Gu, Dahai; Rong, Hua; Wang, Kun; Li, Zhengtian; Talpur, Mir Zulqarnain; Huang, Ying; Wang, Shanrong; Yan, Shixiong; Tong, Huiquan; Zhao, Sumei; Zhao, Guiping; Su, Zhengchang; Ge, Changrong

    2018-01-01

    The growth hormone / insulin-like growth factor-1 (GH/IGF-1) pathway of the somatotropic axis is the major controller for growth rate and body size in vertebrates, but the effect of selection on the expression of GH/IGF-1 somatotropic axis genes and their association with body size and growth performance in farm animals is not fully understood. We analyzed a time series of expression profiles of GH/IGF-1 somatotropic axis genes in two chicken breeds, the Daweishan mini chickens and Wuding chickens, and the commercial Avian broilers hybrid exhibiting markedly different body sizes and growth rates. We found that growth rate and feed conversion efficiency in Daweishan mini chickens were significantly lower than those in Wuding chickens and Avian broilers. The Wuding and Daweishan mini chickens showed higher levels of plasma GH, pituitary GH mRNA but lower levels of hepatic growth hormone receptor (GHR) mRNA than in Avian broilers. Daweishan mini chickens showed significantly lower levels of plasma IGF-1, thigh muscle and hepatic IGF-1 mRNA than did Avian broilers and Wuding chickens. These results suggest that the GH part of the somatotropic axis is the main regulator of growth rate, while IGF-1 may regulate both growth rate and body weight. Selection for growth performance and body size have altered the expression profiles of somatotropic axis genes in a breed-, age-, and tissue-specific manner, and manner, and alteration of regulatory mechanisms of these genes might play an important role in the developmental characteristics of chickens. PMID:29630644

  13. Vertical axis wind turbines: a survey and bibliography

    Energy Technology Data Exchange (ETDEWEB)

    Abramovich, H

    1987-01-01

    The stimulus for the development of modern, big wind turbines has been the world-wide oil crisis during the seventies. Although the horizontal axis wind turbines (HAWT) was the most popular type of wind turbine the Darrieus vertical axis wind turbine (VAWT) has been recognized as a machine with competitive economic potential. The state of the art of the VAWT is reviewed. The wind turbine carrying the name of Darrieus was first proposed by the French inventor in 1925. His original patent covered a range of vertical-axis configurations but the term 'Darrieus' is now generally associated with the curved-blade geometry. In 1966 two researchers at the Canadian NRC again raised the idea of both the straight and curved-blade versions of the Darrieus VAWT.

  14. THE LIMITED EFFECT OF COINCIDENT ORIENTATION ON THE CHOICE OF INTRINSIC AXIS (.).

    Science.gov (United States)

    Li, Jing; Su, Wei

    2015-06-01

    The allocentric system computes and represents general object-to-object spatial relationships to provide a spatial frame of reference other than the egocentric system. The intrinsic frame-of-reference system theory, which suggests people learn the locations of objects based upon an intrinsic axis, is important in research about the allocentric system. The purpose of the current study was to determine whether the effect of coincident orientation on the choice of intrinsic axis was limited. Two groups of participants (24 men, 24 women; M age = 24 yr., SD = 2) encoded different spatial layouts in which the objects shared the coincident orientation of 315° and 225° separately at learning perspective (0°). The response pattern of partial-scene-recognition task following learning reflected different strategies for choosing the intrinsic axis under different conditions. Under the 315° object-orientation condition, the objects' coincident orientation was as important as the symmetric axis in the choice of the intrinsic axis. However, participants were more likely to choose the symmetric axis as the intrinsic axis under the 225° object-orientation condition. The results suggest the effect of coincident orientation on the choice of intrinsic axis is limited.

  15. On the origin of field-aligned beams at the quasi-perpendicular bow shock: multi-spacecraft observations by Cluster

    Directory of Open Access Journals (Sweden)

    H. Kucharek

    2004-07-01

    Full Text Available Two distinct populations of reflected and accelerated ions are known to originate from quasi-perpendicular shocks, gyrating ions and reflected ion beams. Recent observations under such bow shock conditions with Cluster have shown strong evidence that both particle distributions appear to emerge from the same reflection process. In this paper the basic production mechanism of field-aligned beams has been investigated by using CLUSTER multi-spacecraft measurements. We have analyzed several quasi-perpendicular shocks with the Cluster Ion Spectrometry experiment (CIS and followed the spatial and temporal evolution of the reflected and transmitted ion populations across the shock. These observations show that the field-aligned beams most likely result from effective scattering in pitch angle during reflection in the shock ramp. Investigating a low Mach number shock, leakage of a fraction of the thermalized ion distribution in the downstream region does not appear to be the source as the volume in phase space occupied by beam ions is empty downstream of the shock ramp.

  16. Perpendicular magnetic anisotropy influence on voltage-driven spin-diode effect in magnetic tunnel junctions: A micromagnetic study

    Energy Technology Data Exchange (ETDEWEB)

    Frankowski, Marek, E-mail: mfrankow@agh.edu.pl [AGH University of Science and Technology, al. Mickiewicza 30, Department of Electronics, 30-059 Kraków (Poland); Chȩciński, Jakub [AGH University of Science and Technology, al. Mickiewicza 30, Department of Electronics, 30-059 Kraków (Poland); AGH University of Science and Technology, al. Mickiewicza 30, Faculty of Physics and Applied Computer Science, 30-059 Kraków (Poland); Skowroński, Witold; Stobiecki, Tomasz [AGH University of Science and Technology, al. Mickiewicza 30, Department of Electronics, 30-059 Kraków (Poland)

    2017-05-01

    We study the influence of the perpendicular magnetic anisotropy on the voltage-induced ferromagnetic resonance in magnetic tunnel junctions (MTJs). An MTJ response to the applied radio-frequency voltage excitation is investigated using micromagnetic calculations with the free layer oriented both in-plane and out-of-plane. Our model allows for a quantitative description of the magnetic system parameters such as resonance frequency, sensitivity or quality factor and for a distinction between material-dependent internal damping and disorder-dependent effective damping. We find that the sensitivity abruptly increases up to three orders of magnitude near the anisotropy transition regime, while the quality factor declines due to effective damping increase. We attribute the origin of this behaviour to the changes of the exchange energy in the system, which is calculated using micromagnetic approach. - Highlights: • Micromagnetic approach is used for modelling of voltage-induced spin-diode effect. • Voltage-induced switching simulations are performed. • Spin-diode line is analyzed as a function of perpendicular anisotropy energy. • Effective damping, quality factor and sensitivity are calculated.

  17. Growth and characterization of MnGa thin films with perpendicular magnetic anisotropy on BiSb topological insulator

    Science.gov (United States)

    Duy Khang, Nguyen Huynh; Ueda, Yugo; Yao, Kenichiro; Hai, Pham Nam

    2017-10-01

    We report on the crystal growth as well as the structural and magnetic properties of Bi0.8Sb0.2 topological insulator (TI)/MnxGa1-x bi-layers grown on GaAs(111)A substrates by molecular beam epitaxy. By optimizing the growth conditions and Mn composition, we were able to grow MnxGa1-x thin films on Bi0.8Sb0.2 with the crystallographic orientation of Bi0.8Sb0.2(001)[1 1 ¯ 0]//MnGa (001)[100]. Using magnetic circular dichroism (MCD) spectroscopy, we detected both the L10 phase ( x 0.6 ) of MnxGa1-x. For 0.50 ≤ x ≤ 0.55 , we obtained ferromagnetic L10-MnGa thin films with clear perpendicular magnetic anisotropy, which were confirmed by MCD hysteresis, anomalous Hall effect as well as superconducting quantum interference device measurements. Our results show that the BiSb/MnxGa1-x bi-layer system is promising for perpendicular magnetization switching using the giant spin Hall effect in TIs.

  18. Evidence for nanoscale two-dimensional Co clusters in CoPt{sub 3} films with perpendicular magnetic anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Cross, J O [Department of Physics, University of Washington, Seattle, WA 98195 (United States); Newville, M [Consortium for Advanced Radiation Sources, University of Chicago, Chicago, IL 60637 (United States); Maranville, B B; Hellman, F [Department of Physics, University of California at San Diego, La Jolla, CA 92093 (United States); Bordel, C [Department of Physics, University of California at Berkeley, CA 94720 (United States); Harris, V G, E-mail: cbordel@berkeley.ed [Department of Electrical and Computer Engineering, Northeastern University, Boston, MA 02115 (United States)

    2010-04-14

    The length scale of the local chemical anisotropy responsible for the growth-temperature-induced perpendicular magnetic anisotropy of face-centered cubic CoPt{sub 3} alloy films was investigated using polarized extended x-ray absorption fine structure (EXAFS). These x-ray measurements were performed on a series of four (111) CoPt{sub 3} films epitaxially grown on (0001) sapphire substrates. The EXAFS data show a preference for Co-Co pairs parallel to the film plane when the film exhibits magnetic anisotropy, and random chemical order otherwise. Furthermore, atomic pair correlation anisotropy was evidenced only in the EXAFS signal from the next neighbors to the absorbing Co atoms and from multiple scattering paths focused through the next neighbors. This suggests that the Co clusters are no more than a few atoms in extent in the plane and one monolayer in extent out of the plane. Our EXAFS results confirm the correlation between perpendicular magnetic anisotropy and two-dimensional Co segregation in CoPt{sub 3} alloy films, and establish a length scale on the order of 10 A for the Co clusters.

  19. Effects of high fat diet on the Basal activity of the hypothalamus-pituitary-adrenal axis in mice: a systematic review.

    Science.gov (United States)

    Auvinen, H E; Romijn, J A; Biermasz, N R; Havekes, L M; Smit, J W A; Rensen, P C N; Pereira, A M

    2011-12-01

    Hypothalamus-pituitary-adrenal-axis activity is suggested to be involved in the pathophysiology of the metabolic syndrome. In diet-induced obesity mouse models, features of the metabolic syndrome are induced by feeding high fat diet. However, the models reveal conflicting results with respect to the hypothalamus-pituitary-adrenal-axis activation. The aim of this review was to assess the effects of high fat feeding on the activity of the hypothalamus-pituitary-adrenal-axis in mice. PubMed, EMBASE, Web of Science, the Cochrane database, and Science Direct were electronically searched and reviewed by 2 individual researchers. We included only original mouse studies reporting parameters of the hypothalamus-pituitary-adrenal-axis after high fat feeding, and at least 1 basal corticosterone level with a proper control group. Studies with adrenalectomized mice, transgenic animals only, high fat diet for less than 2 weeks, or other interventions besides high fat diet, were excluded. 20 studies were included. The hypothalamus-pituitary-adrenal-axis evaluation was the primary research question in only 5 studies. Plasma corticosterone levels were unchanged in 40%, elevated in 30%, and decreased in 20% of the studies. The effects in the peripheral tissues and the central nervous system were also inconsistent. However, major differences were found between mouse strains, experimental conditions, and the content and duration of the diets. This systematic review demonstrates that the effects of high fat feeding on the basal activity of the hypothalamus-pituitary-adrenal-axis in mice are limited and inconclusive. Differences in experimental conditions hamper comparisons and accentuate the need for standardized evaluations to discern the effects of diet-induced obesity on the hypothalamus-pituitary-adrenal-axis. © Georg Thieme Verlag KG Stuttgart · New York.

  20. Improvements in radiological apparatus

    International Nuclear Information System (INIS)

    Grady, J.K.

    1985-01-01

    Improvements in radiological apparatus are described which allow better unilateral access to the patient. A base mounts ring supports for rotation about an axis and a table for supporting a subject is fitted to the ring support. An X-ray tube and receptor are held on opposite ends of a two-limbed carriage and radiation axis. The carriage is mounted on a sliding arm carried on the ring support and extending parallel to the rotational axis of the support. The carriage also pivots on the arm about an axis perpendicular to the rotational axis and to the radiation axis. (author)

  1. Measurement Axis Searching Model for Terrestrial Laser Scans Registration

    Directory of Open Access Journals (Sweden)

    Shaoxing Hu

    2016-01-01

    Full Text Available Nowadays, terrestrial Lidar scans can cover rather a large area; the point densities are strongly varied because of the line-of-sight measurement principle in potential overlaps with scans taken from different viewpoints. Most of the traditional methods focus on registration algorithm and ignore searching model. Sometimes the traditional methods are directly used to align two point clouds; a large critically unsolved problem of the large biases will be created in areas distant from the overlaps while the local overlaps are often aligned well. So a novel measurement axis searching model (MASM has been proposed in this paper. The method includes four steps: (1 the principal axis fitting, (2 the measurement axis generation, (3 low-high-precision search, and (4 result generation. The principal axis gives an orientation to the point cloud; the search scope is limited by the measurement axis. The point cloud orientation can be adjusted gradually until the achievement of the global optimum using low- and high-precision search. We perform some experiments with simulated point clouds and real terrestrial laser scans. The results of simulated point clouds have shown the processing steps of our method, and the results of real terrestrial laser scans have shown the sensitivity of the approach with respect to the indoor and outdoor scenes.

  2. On the generation of short-axis and radial long-axis slices in thallium-201 myocardial perfusion single-photon emission tomography

    International Nuclear Information System (INIS)

    Hastenberg, R.P.J.M. van; Eindhoven Univ. of Technology; Kemernik, G.J.; Hasman, A.

    1996-01-01

    We tried to develop fully automatic reorientation algorithms in thallium-201 myocardial perfusion single-photon emission tomography, and tested a method to evaluate the quality of reorientation. The left ventricle was automatically segmented using count density information, contours generated with Laplacian operators in both transaxial and sagittal slices, and morphological and positional characteristics of the contours. Reorientation was automatically performed based on knowledge of the long axis of a second degree surface fitted to the myocardial wall. We tried to achieve improvement in reorientation without relying on any functional description of left ventricular shape. Quality of reorientation was evaluated and improved using interactive tools in combination with radial long-axis slices. Two groups of 50 patients, after stress and rest, were analysed using the traditional manual and the fully automatic procedures. Automatic segmentation was successful in 98 out of 100 cases, and automatic reorientation was of reasonable quality. Reorientation obtained with the radial long-axis slices tool was better than after traditional manual or automatic reorientation. Automatic reorientation based on second degree surface fitting was in our hands less successful than reported in the literature. The tool using radial long-axis slices provides a better standard for testing reorientation algorithms than the traditional manual method. (orig.)

  3. Large eddy simulation of fire-induced buoyancy driven plume dispersion in an urban street canyon under perpendicular wind flow

    Energy Technology Data Exchange (ETDEWEB)

    Hu, L.H., E-mail: hlh@ustc.edu.cn [State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230026 (China); Huo, R.; Yang, D. [State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2009-07-15

    The dispersion of fire-induced buoyancy driven plume in and above an idealized street canyon of 18 m (width) x 18 m (height) x 40 m (length) with a wind flow perpendicular to its axis was investigated by Fire Dynamics Simulator (FDS), Large Eddy Simulation (LES). Former studies, such as that by Oka [T.R. Oke, Street design and urban canopy layer climate, Energy Build. 11 (1988) 103-113], Gayev and Savory [Y.A. Gayev, E. Savory, Influence of street obstructions on flow processes within street canyons. J. Wind Eng. Ind. Aerodyn. 82 (1999) 89-103], Xie et al. [S. Xie, Y. Zhang, L. Qi, X. Tang, Spatial distribution of traffic-related pollutant concentrations in street canyons. Atmos. Environ. 37 (2003) 3213-3224], Baker et al. [J. Baker, H. L. Walker, X. M. Cai, A study of the dispersion and transport of reactive pollutants in and above street canyons-a large eddy simulation, Atmos. Environ. 38 (2004) 6883-6892] and Baik et al. [J.-J. Baik, Y.-S. Kang, J.-J. Kim, Modeling reactive pollutant dispersion in an urban street canyon, Atmos. Environ. 41 (2007) 934-949], focus on the flow pattern and pollutant dispersion in the street canyon with no buoyancy effect. Results showed that with the increase of the wind flow velocity, the dispersion pattern of a buoyant plume fell into four regimes. When the wind flow velocity increased up to a certain critical level, the buoyancy driven upward rising plume was re-entrained back into the street canyon. This is a dangerous situation as the harmful fire smoke will accumulate to pollute the environment and thus threaten the safety of the people in the street canyon. This critical re-entrainment wind velocity, as an important parameter to be concerned, was further revealed to increase asymptotically with the heat/buoyancy release rate of the fire.

  4. Large eddy simulation of fire-induced buoyancy driven plume dispersion in an urban street canyon under perpendicular wind flow.

    Science.gov (United States)

    Hu, L H; Huo, R; Yang, D

    2009-07-15

    The dispersion of fire-induced buoyancy driven plume in and above an idealized street canyon of 18 m (width) x 18 m (height) x 40 m (length) with a wind flow perpendicular to its axis was investigated by Fire Dynamics Simulator (FDS), Large Eddy Simulation (LES). Former studies, such as that by Oka [T.R. Oke, Street design and urban canopy layer climate, Energy Build. 11 (1988) 103-113], Gayev and Savory [Y.A. Gayev, E. Savory, Influence of street obstructions on flow processes within street canyons. J. Wind Eng. Ind. Aerodyn. 82 (1999) 89-103], Xie et al. [S. Xie, Y. Zhang, L. Qi, X. Tang, Spatial distribution of traffic-related pollutant concentrations in street canyons. Atmos. Environ. 37 (2003) 3213-3224], Baker et al. [J. Baker, H. L. Walker, X. M. Cai, A study of the dispersion and transport of reactive pollutants in and above street canyons--a large eddy simulation, Atmos. Environ. 38 (2004) 6883-6892] and Baik et al. [J.-J. Baik, Y.-S. Kang, J.-J. Kim, Modeling reactive pollutant dispersion in an urban street canyon, Atmos. Environ. 41 (2007) 934-949], focus on the flow pattern and pollutant dispersion in the street canyon with no buoyancy effect. Results showed that with the increase of the wind flow velocity, the dispersion pattern of a buoyant plume fell into four regimes. When the wind flow velocity increased up to a certain critical level, the buoyancy driven upward rising plume was re-entrained back into the street canyon. This is a dangerous situation as the harmful fire smoke will accumulate to pollute the environment and thus threaten the safety of the people in the street canyon. This critical re-entrainment wind velocity, as an important parameter to be concerned, was further revealed to increase asymptotically with the heat/buoyancy release rate of the fire.

  5. Large eddy simulation of fire-induced buoyancy driven plume dispersion in an urban street canyon under perpendicular wind flow

    International Nuclear Information System (INIS)

    Hu, L.H.; Huo, R.; Yang, D.

    2009-01-01

    The dispersion of fire-induced buoyancy driven plume in and above an idealized street canyon of 18 m (width) x 18 m (height) x 40 m (length) with a wind flow perpendicular to its axis was investigated by Fire Dynamics Simulator (FDS), Large Eddy Simulation (LES). Former studies, such as that by Oka [T.R. Oke, Street design and urban canopy layer climate, Energy Build. 11 (1988) 103-113], Gayev and Savory [Y.A. Gayev, E. Savory, Influence of street obstructions on flow processes within street canyons. J. Wind Eng. Ind. Aerodyn. 82 (1999) 89-103], Xie et al. [S. Xie, Y. Zhang, L. Qi, X. Tang, Spatial distribution of traffic-related pollutant concentrations in street canyons. Atmos. Environ. 37 (2003) 3213-3224], Baker et al. [J. Baker, H. L. Walker, X. M. Cai, A study of the dispersion and transport of reactive pollutants in and above street canyons-a large eddy simulation, Atmos. Environ. 38 (2004) 6883-6892] and Baik et al. [J.-J. Baik, Y.-S. Kang, J.-J. Kim, Modeling reactive pollutant dispersion in an urban street canyon, Atmos. Environ. 41 (2007) 934-949], focus on the flow pattern and pollutant dispersion in the street canyon with no buoyancy effect. Results showed that with the increase of the wind flow velocity, the dispersion pattern of a buoyant plume fell into four regimes. When the wind flow velocity increased up to a certain critical level, the buoyancy driven upward rising plume was re-entrained back into the street canyon. This is a dangerous situation as the harmful fire smoke will accumulate to pollute the environment and thus threaten the safety of the people in the street canyon. This critical re-entrainment wind velocity, as an important parameter to be concerned, was further revealed to increase asymptotically with the heat/buoyancy release rate of the fire.

  6. The manufacturing and metrology of off-axis mirrors

    Science.gov (United States)

    Penzkofer, Karlheinz; Rascher, Rolf; Küpper, Lutz; Liebl, Johannes

    2015-10-01

    Especially in the area of the large mirror manufacturing only a few manufacturers are capable to produce optical surfaces of high quality. Therefore a deterministic process should be developed in the project IFasO. In the field of telescope optics off-axis optical systems are becoming increasingly important. These systems try to avoid an obstructing of the incoming light by moving the secondary mirror out of the primary mirror's optical axis. This advantage leads to an increasing market for this type of optical surface. Until now off-axis mirrors were difficult or almost impossible to produce. With the processes developed in IFasO, high quality mirrors become possible. For this reason, this paper describes the manufacturing of off-axis surfaces and its problems. The mirror production used in the project IFasO is based on the specific design of the CNC center developed by the company Optotech. This center UPG2000 is capable of grinding, polishing, sagitta measurement and interferometric measurement in one mounting of the specimen. Usually a large optics has to be transported during their manufacturing after every individual process step. There is always a risk of damage of the specimen. The exact orientation of the surface relatively to the tool position is also required. This takes a huge amount of time and makes up most of the production time. In this presentation the use of UPG2000 and the next steps within the process development are described. In the current status the manufacturing of large off-axis elements with a PV < λ/10 rms is reproducible.

  7. Design and implementation of five-axis transformation function in CNC system

    Directory of Open Access Journals (Sweden)

    Wang Feng

    2014-04-01

    Full Text Available To implement five-axis functions in CNC system, based on domestic system Lan Tian series, an improved design method for the system software structure is proposed in this paper. The numerical control kernel of CNC system is divided into the task layer and the motion layer. A five-axis transformation unit is integrated into the motion layer. After classifying five-axis machines into different types and analyzing their geometry information, the five-axis kinematic library is designed according to the abstract factory pattern. Furthermore, by taking CA spindle-tilting machine as an example, the forward and the inverse kinematic transformations are deduced. Based on the new software architecture and the five-axis kinematic library, algorithms of RTCP (rotation tool center point control and 3D radius compensation for end-milling are designed and realized. The milling results show that, with five-axis functions based on such software structure, the instructions with respect to the cutter’s position and orientation can be directly carried out in the CNC system.

  8. Theory of coherent c-axis Josephson tunneling between layered superconductors

    International Nuclear Information System (INIS)

    Arnold, G. B.; Klemm, R. A.

    2000-01-01

    We calculate exactly the Josephson current for c-axis coherent tunneling between two layered superconductors, each with internal coherent tight-binding intra- and interlayer quasiparticle dispersions. Our results also apply when one or both of the superconductors is a bulk material, and include the usually neglected effects of surface states. For weak tunneling, our results reduce to our previous results derived using the tunneling Hamiltonian. Our results are also correct for strong tunneling. However, the c-axis tunneling expressions of Tanaka and Kashiwaya are shown to be incorrect in any limit. In addition, we consider the c-axis coherent critical current between two identical layered superconductors twisted an angle φ 0 about the c axis with respect to each other. Regardless of the order-parameter symmetry, our coherent tunneling results using a tight-binding intralayer quasiparticle dispersion are inconsistent with the recent c-axis twist bicrystal Bi 2 Sr 2 CaCu 2 O 8+δ twist junction experiments of Li et al. [Li et al., Phys. Rev. Lett. 83, 4160 (1999)]. (c) 2000 The American Physical Society

  9. Axis-switching of a micro-jet

    Science.gov (United States)

    Cabaleiro, Juan Martin; Aider, Jean-Luc

    2014-03-01

    In this study, it is shown that free microjets can undergo complex transitions similar to large-scale free jets despite relatively low Reynolds numbers. Using an original experimental method allowing for the 3D reconstruction of the instantaneous spatial organization of the microjet, the axis-switching of a micro-jet is observed for the first time. This is the first experimental evidence of such complex phenomena for free micro-jets. Combining these experimental results with Direct Numerical Simulations it is shown that the mechanism responsible for the axis-switching is the deformation of a micro-vortex ring due to induction by the corner vortices, as it occurs in large scale non-circular jets.

  10. A Nanoscale Plasma Etching Process for Pole Tip Recession of Perpendicular Recording Magnetic Head

    OpenAIRE

    LIU, Shoubin; HE, Dayao

    2017-01-01

    The pole tip of perpendicular recording head is constructed in a stacked structure with materials of NiCoFe, NiFe, Al2O3 and AlTiC. The surfaces of different materials are set at different heights below the air-bearing surface of slider. This paper presented a plasma dry etching process for Pole Tip Recession (PTR) based on an ion beam etching system. Ar and O2 mixed plasma at small incident angles have a high removal rate to the nonmagnetic material. It was utilised to etch the reference sur...

  11. Calibration of three-axis magnetometers with differential evolution algorithm

    International Nuclear Information System (INIS)

    Pang, Hongfeng; Zhang, Qi; Wang, Wei; Wang, Junya; Li, Ji; Luo, Shitu; Wan, Chengbiao; Chen, Dixiang; Pan, Mengchun; Luo, Feilu

    2013-01-01

    The accuracy of three-axis magnetometers is influenced by different scale and bias of each axis and nonorthogonality between axes. One limitation of traditional iteration methods is that initial parameters influence the calibration, thus leading to the local optimal or wrong results. In this paper, a new method is proposed to calibrate three-axis magnetometers. To employ this method, a nonmagnetic rotation platform, a proton magnetometer, a DM-050 three-axis magnetometer and the differential evolution (DE) algorithm are used. The performance of this calibration method is analyzed with simulation and experiment. In simulation, the calibration results of DE, unscented Kalman filter (UKF), recursive least squares (RLS) and genetic algorithm (GA) are compared. RMS error using DE is least, which is reduced from 81.233 nT to 1.567 nT. Experimental results show that comparing with UKF, RLS and GA, the DE algorithm has not only the least calibration error but also the best robustness. After calibration, RMS error is reduced from 68.914 nT to 2.919 nT. In addition, the DE algorithm is not sensitive to initial parameters, which is an important advantage compared with traditional iteration algorithms. The proposed algorithm can avoid the troublesome procedure to select suitable initial parameters, thus it can improve the calibration performance of three-axis magnetometers. - Highlights: • The calibration results and robustness of UKF, GA, RLS and DE algorithm are analyzed. • Calibration error of DE is the least in simulation and experiment. • Comparing with traditional calibration algorithms, DE is not sensitive to initial parameters. • It can improve the calibration performance of three-axis magnetometers

  12. Studies of current-perpendicular-to-plane magnetoresistance (CPP-MR) and current-induced magnetization switching (CIMS)

    Science.gov (United States)

    Kurt, Huseyin

    2005-08-01

    We present two CPP-MR studies of spin-valves based upon ferromagnetic/nonmagnetic/ferromagnetic (F/N/F) trilayers. We measure the spin-diffusion lengths of N = Pd, Pt, and Au at 4.2K, and both the specific resistances (sample area A times resistance R) and spin-memory-loss of N/Cu interfaces. Pd, Pt and Au are of special device interest because they give perpendicular anisotropy when sandwiching very thin Co layers. Comparing our spin-memory-loss data at Pd/Cu and Pt/Cu interfaces with older data for Nb/Cu and W/Cu gives insight into the importance of spin-orbit coupling in producing such loss. We reproduce and extend prior studies by Eid of 'magnetic activity' at the interface of Co and N-metals (or combinations of N-metals), when the other side of the N-metal contacts a superconductor (S). Our data suggest that magnetic activity may require strong spin-flipping at the N/S interface. We present five studies of a new phenomenon, CIMS, in F1/N/F2 trilayers, with F1 a thick 'polarizing' layer and F2 a thin 'switching' layer. In all prior studies of CIMS, positive current caused the magnetization of F2 to switch from parallel (P) to anti-parallel (AP) to that of F1- 'normal' switching. By judicious addition of impurities to F-metals, we are able to controllably produce both 'normal' and 'inverse' switching- where positive current switches the magnetization of F2 from AP to P to that of F1. In the samples studied, whether the switching is normal or inverse is set by the 'net polarization' produced by F1 and is independent of the properties of F2. As scattering in the bulk of F1 and F2 is essential to producing our results, these results cannot be described by ballistic models, which allow scattering only at interfaces. Most CIMS experiments use Cu as the N-layer due to its low resistivity and long spin-diffusion length. We show that Ag and Au have low enough resistivities and long enough spin-diffusion lengths to be useful alternatives to Cu for some devices. While

  13. Dynamic transitions in a model of the hypothalamic-pituitary-adrenal axis

    Science.gov (United States)

    Čupić, Željko; Marković, Vladimir M.; Maćešić, Stevan; Stanojević, Ana; Damjanović, Svetozar; Vukojević, Vladana; Kolar-Anić, Ljiljana

    2016-03-01

    Dynamic properties of a nonlinear five-dimensional stoichiometric model of the hypothalamic-pituitary-adrenal (HPA) axis were systematically investigated. Conditions under which qualitative transitions between dynamic states occur are determined by independently varying the rate constants of all reactions that constitute the model. Bifurcation types were further characterized using continuation algorithms and scale factor methods. Regions of bistability and transitions through supercritical Andronov-Hopf and saddle loop bifurcations were identified. Dynamic state analysis predicts that the HPA axis operates under basal (healthy) physiological conditions close to an Andronov-Hopf bifurcation. Dynamic properties of the stress-control axis have not been characterized experimentally, but modelling suggests that the proximity to a supercritical Andronov-Hopf bifurcation can give the HPA axis both, flexibility to respond to external stimuli and adjust to new conditions and stability, i.e., the capacity to return to the original dynamic state afterwards, which is essential for maintaining homeostasis. The analysis presented here reflects the properties of a low-dimensional model that succinctly describes neurochemical transformations underlying the HPA axis. However, the model accounts correctly for a number of experimentally observed properties of the stress-response axis. We therefore regard that the presented analysis is meaningful, showing how in silico investigations can be used to guide the experimentalists in understanding how the HPA axis activity changes under chronic disease and/or specific pharmacological manipulations.

  14. Laser heating and oxygen partial pressure effects on the dynamic magnetic properties of perpendicular CoFeAlO films

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Di [Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education), Department of Optical Science and Engineering, Fudan University, Shanghai 200433 (China); Li, Wei [State Key Laboratory of Precision Spectroscopy and Department of Physics, East China Normal University, Shanghai 200062 (China); Tang, Minghong [Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education), Department of Optical Science and Engineering, Fudan University, Shanghai 200433 (China); Zhang, Zongzhi, E-mail: zzzhang@fudan.edu.cn [Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education), Department of Optical Science and Engineering, Fudan University, Shanghai 200433 (China); Lou, Shitao [State Key Laboratory of Precision Spectroscopy and Department of Physics, East China Normal University, Shanghai 200062 (China); Jin, Q.Y. [Key Laboratory of Micro and Nano Photonic Structures (Ministry of Education), Department of Optical Science and Engineering, Fudan University, Shanghai 200433 (China); State Key Laboratory of Precision Spectroscopy and Department of Physics, East China Normal University, Shanghai 200062 (China)

    2016-07-01

    The impact of oxidation and laser heating on the dynamic magnetic properties of perpendicularly magnetized Co{sub 50}Fe{sub 25}Al{sub 25}O films has been studied by time-resolved magneto-optical Kerr effect in a fs-laser pump-probe setup. We find that pump laser fluence F{sub p} can affect the effective magnetic anisotropy field and thus the precession frequency f seriously, leading to an increased dependence of effective magnetic damping factor α{sub eff} on the external field at higher fluences. Moreover, the α{sub eff} increases with increasing the oxygen partial pressure P{sub O2} while the uniaxial anisotropy energy K{sub u} and Landau factor g decrease, owing to the increased proportion of superparamagnetic CoFe oxides formed by over-oxidation. By optimizing both the F{sub p} and P{sub O2}, the intrinsic damping factor is determined to be lower than 0.028 for the perpendicular film showing a uniaxial anisotropy energy as high as 4.3×10{sup 6} erg/cm{sup 3}. The results in this study provide a promising approach to manipulate the magnetic parameters for possible applications in spintronic devices. - Highlights: • A new kind of perpendicular thin film material, oxidized CoFeAl, has been fabricated. • The precession frequency and effective damping are strongly affected by higher fluence. • The effective damping factor increases with oxygen partial pressure. • The intrinsic damping factor is below 0.028 for the CFAO film with K{sub u}=4.3×10{sup 6} erg/cm{sup 3}.

  15. Development of a model counter-rotating type horizontal-axis tidal turbine

    Science.gov (United States)

    Huang, B.; Yoshida, K.; Kanemoto, T.

    2016-05-01

    In the past decade, the tidal energies have caused worldwide concern as it can provide regular and predictable renewable energy resource for power generation. The majority of technologies for exploiting the tidal stream energy are based on the concept of the horizontal axis tidal turbine (HATT). A unique counter-rotating type HATT was proposed in the present work. The original blade profiles were designed according to the developed blade element momentum theory (BEMT). CFD simulations and experimental tests were adopted to the performance of the model counter-rotating type HATT. The experimental data provides an evidence of validation of the CFD model. Further optimization of the blade profiles was also carried out based on the CFD results.

  16. Reversible electron heating vs. wave-particle interactions in quasi-perpendicular shocks

    Science.gov (United States)

    Veltri, P.; Mangeney, A.; Scudder, J. D.

    1992-01-01

    The energy necessary to explain the electron heating in quasi-perpendicular collisionless shocks can be derived either from the electron acceleration in the d.c. cross shock electric potential, or by the interactions between the electrons and the waves existing in the shock. A Monte Carlo simulation has been performed to study the electron distribution function evolution through the shock structure, with and without particle diffusion on waves. This simulation has allowed us to clarify the relative importance of the two possible energy sources; in particular it has been shown that the electron parallel temperature is determined by the d.c. electromagnetic field and not by any wave-particle-induced heating. Wave particle interactions are effective in smoothing out the large gradients in phase space produced by the 'reversible' motion of the electrons, thus producing a 'cooling' of the electrons.

  17. Magnetic Reversal and Thermal Stability of CoFeB Perpendicular Magnetic Tunnel Junction Arrays Patterned by Block Copolymer Lithography

    KAUST Repository

    Tu, Kun-Hua; Fernandez Martin, Eduardo; almasi, hamid; Wang, Weigang; Navas Otero, David; Ntetsikas, Konstantinos; Moschovas, Dimitrios; Avgeropoulos, Apostolos; Ross, Caroline A

    2018-01-01

    Dense arrays of pillars, with diameters of 64 and 25 nm, were made from a perpendicular CoFeB magnetic tunnel junction thin film stack using block copolymer lithography. While the soft layer and hard layer in the 64 nm pillars reverse at different

  18. Velocity measurement of model vertical axis wind turbines

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, D.A.; McWilliam, M. [Waterloo Univ., ON (Canada). Dept. of Mechanical Engineering

    2006-07-01

    An increasingly popular solution to future energy demand is wind energy. Wind turbine designs can be grouped according to their axis of rotation, either horizontal or vertical. Horizontal axis wind turbines have higher power output in a good wind regime than vertical axis turbines and are used in most commercial class designs. Vertical axis Savonius-based wind turbine designs are still widely used in some applications because of their simplistic design and low wind speed performance. There are many design variables that must be considered in order to optimize the power output in a given wind regime in a typical wind turbine design. Using particle image velocimetry, a study of the air flow around five different model vertical axis wind turbines was conducted in a closed loop wind tunnel. A standard Savonius design with two semi-circular blades overlapping, and two variations of this design, a deep blade and a shallow blade design were among the turbine models included in this study. It also evaluated alternate designs that attempt to increase the performance of the standard design by allowing compound blade curvature. Measurements were collected at a constant phase angle and also at random rotor orientations. It was found that evaluation of the flow patterns and measured velocities revealed consistent and stable flow patterns at any given phase angle. Large scale flow structures are evident in all designs such as vortices shed from blade surfaces. An important performance parameter was considered to be the ability of the flow to remain attached to the forward blade and redirect and reorient the flow to the following blade. 6 refs., 18 figs.

  19. Neuroactive steroids modulate HPA axis activity and cerebral brain-derived neurotrophic factor (BDNF) protein levels in adult male rats.

    Science.gov (United States)

    Naert, Gaëlle; Maurice, Tangui; Tapia-Arancibia, Lucia; Givalois, Laurent

    2007-01-01

    Depression is characterized by hypothalamo-pituitary-adrenocortical (HPA) axis hyperactivity. In this major mood disorder, neurosteroids and neurotrophins, particularly brain-derived neurotrophic factor (BDNF), seem to be implicated and have some antidepressant effects. BDNF is highly involved in regulation of the HPA axis, whereas neurosteroids effects have never been clearly established. In this systematic in vivo study, we showed that the principal neuroactive steroids, namely dehydroepiandrosterone (DHEA), pregnenolone (PREG) and their sulfate esters (DHEA-S and PREG-S), along with allopregnanolone (ALLO), stimulated HPA axis activity, while also modulating central BDNF contents. In detail, DHEA, DHEA-S, PREG, PREG-S and ALLO induced corticotropin-releasing hormone (CRH) and/or arginine vasopressin (AVP) synthesis and release at the hypothalamic level, thus enhancing plasma adrenocorticotropin hormone (ACTH) and corticosterone (CORT) concentrations. This stimulation of the HPA axis occurred concomitantly with BDNF modifications at the hippocampus, amygdala and hypothalamus levels. We showed that these neurosteroids induced rapid effects, probably via neurotransmitter receptors and delayed effects perhaps after metabolization in other neuroactive steroids. We highlighted that they had peripheral effects directly at the adrenal level by inducing CORT release, certainly after estrogenic metabolization. In addition, we showed that, at the dose used, only DHEA, DHEA-S and PREG-S had antidepressant effects. In conclusion, these results highly suggest that part of the HPA axis and antidepressant effects of neuroactive steroids could be mediated by BDNF, particularly at the amygdala level. They also suggest that neurosteroids effects on central BDNF could partially explain the trophic properties of these molecules.

  20. MMS Observation of Shock-Reflected He++ at Earth's Quasi-Perpendicular Bow Shock

    Science.gov (United States)

    Broll, Jeffrey Michael; Fuselier, S. A.; Trattner, K. J.; Schwartz, S. J.; Burch, J. L.; Giles, B. L.; Anderson, B. J.

    2018-01-01

    Specular reflection of protons at Earth's supercritical quasi-perpendicular bow shock has long been known to lead to the thermalization of solar wind particles by velocity-space dispersion. The same process has been proposed for He++ but could not be confirmed previously due to insufficient time resolution for velocity distribution measurements. We present observations and simulations of a bow shock crossing by the Magnetospheric Multiscale (MMS) mission on 20 November 2015 indicating that a very similar reflection process for He++ is possible, and further that the part of the incoming distribution with the highest probability of reflecting is the same for H+ and He++. However, the reflection process for He++ is accomplished by deeper penetration into the downstream magnetic fields.

  1. Numerical studies of electron dynamics in oblique quasi-perpendicular collisionless shock waves

    International Nuclear Information System (INIS)

    Liewer, P.C.; Decyk, V.K.; Dawson, J.M.; Lembege, B.

    1991-01-01

    Linear and nonlinear electron damping of the whistler precursor wave train to low Mach number quasi-perpendicular oblique shocks is studied using a one-dimensional electromagnetic plasma simulation code with particle electrons and ions. In some parameter regimes, electrons are observed to trap along the magnetic field lines in the potential of the whistler precursor wave train. This trapping can lead to significant electron heating in front of the shock for β e (∼10% or less). Use of the 64-processor Caltech/JPL Mark IIIfp hypercube concurrent computer has enables us to make long runs using realistic mass ratios (m i /m e = 1,600) in the full particle in-cell code and thus simulate shock parameter regimes and phenomena not previously studied numerically

  2. Functional Implications of the IL-23/IL-17 Immune Axis in Schizophrenia.

    Science.gov (United States)

    Debnath, Monojit; Berk, Michael

    2017-12-01

    The aetiology of schizophrenia seems to stem from complex interactions amongst environmental, genetic, metabolic, immunologic and oxidative components. Chronic low-grade inflammation has been persistently linked to schizophrenia, and this has primarily been based on the findings derived from Th1/Th2 cytokine balance. While the IL-23/IL-17 axis plays crucial role in the pathogenesis of several immune-mediated disorders, it has remained relatively unexplored in neuropsychiatric disorders. Altered levels of cytokines related to IL-23/IL-17 axis have been observed in schizophrenia patients in a few studies. In addition, other indirect factors known to confer schizophrenia risk like complement activation and altered gut microbiota are shown to modulate the IL-23/IL-17 axis. These preliminary observations provide crucial clues about the functional implications of IL-23/IL-17 axis in schizophrenia. In this review, an attempt has been made to highlight the biology of IL-23/IL-17 axis and its relevance to schizophrenia risk and pathogenesis. Given the pathogenic potential of the IL-23/IL-17 axis, therapeutic targeting of this axis may be a promising approach to benefit patients suffering from this devastating disorder.

  3. Sequence-dependent rotation axis changes and interaction torque use in overarm throwing.

    Science.gov (United States)

    Hansen, Clint; Rezzoug, Nasser; Gorce, Philippe; Venture, Gentiane; Isableu, Brice

    2016-01-01

    We examined the role of rotation axes during an overarm throwing task. Participants performed such task and were asked to throw a ball at maximal velocity at a target. The purpose of this study was to examine whether the minimum inertia axis would be exploited during the throwing phases, a time when internal-external rotations of the shoulder are particularly important. A motion capture system was used to evaluate the performance and to compute the potential axes of rotation (minimum inertia axis, shoulder-centre of mass axis and the shoulder-elbow axis). More specifically, we investigated whether a velocity-dependent change in rotational axes can be observed in the different throwing phases and whether the control obeys the principle of minimum inertia resistance. Our results showed that the limbs' rotational axis mainly coincides with the minimum inertia axis during the cocking phase and with the shoulder-elbow axis during the acceleration phase. Besides these rotation axes changes, the use of interaction torque is also sequence-dependent. The sequence-dependent rotation axes changes associated with the use of interaction torque during the acceleration phase could be a key factor in the production of hand velocity at ball release.

  4. Spin-dependent electronic transport characteristics in Fe4N/BiFeO3/Fe4N perpendicular magnetic tunnel junctions

    Science.gov (United States)

    Yin, Li; Wang, Xiaocha; Mi, Wenbo

    2018-01-01

    Perpendicular magnetic tunnel junctions (MTJs) have attracted increasing attention owing to the low energy consumption and wide application prospects. Herewith, against Julliere's formula, an inverse tunnel magnetoresistance (TMR) appears in tetragonal Fe4N/BiFeO3/Fe4N perpendicular MTJs, which is attributed to the binding between the interface resonant tunneling state and central (bordered) hot spots. Especially, antiferromagnetic BiFeO3 shows an extra spin-polarized resonant state in the barrier, which provides a magnetic-barrier factor to affect the tunneling transport in MTJs. Meanwhile, due to the spin-polarized transport in Fe4N/BiFeO3/Fe4N MTJs, the sign of TMR can be tuned by the applied bias. The tunable TMR and resonant magnetic barrier effect pave the way for clarifying the tunneling transport in other junctions and spintronic devices.

  5. Usefulness of Non-coplanar Helical Tomotherapy Using Variable Axis Baseplate

    International Nuclear Information System (INIS)

    Ha, Jin Sook; Chung, Yoon Sun; Lee, Ik Jae; Shin, Dong Bong; Kim, Jong Dae; Kim, Sei Joon; Jeon, Mi Jin; Chok, Yoon Jin; Kim, Ki Kwang; Lee, Seul Bee

    2011-01-01

    Helical Tomotherapy allows only coplanar beam delivery because it does not allow couch rotation. We investigated a method to introduce non-coplanar beam by tilting a patient's head for Tomotherapy. The aim of this study was to compare intrafractional movement during Tomotherapy between coplanar and non-coplanar patient's setup. Helical Tomotherapy was used for treating eight patients with intracranial tumor. The subjects were divided into three groups: one group (coplanar) of 2 patients who lay on S-plate with supine position and wore thermoplastic mask for immobilizing the head, second group (non-coplanar) of 3 patients who lay on S-plate with supine position and whose head was tilted with Variable Axis Baseplate and wore thermoplastic mask, and third group (non-coplanar plus mouthpiece) of 3 patients whose head was tilted and wore a mouthpiece immobilization device and thermoplastic mask. The patients were treated with Tomotherapy after treatment planning with Tomotherapy Planning System. Megavoltage computed tomography (MVCT) was performed before and after treatment, and the intrafractional error was measured with lateral(X), longitudinal(Y), vertical(Z) direction movements and vector (√x 2 +√y 2 +√z 2 ) value for assessing overall movement. Intrafractional error was compared among three groups by taking the error of MVCT taken after the treatment. As the correction values (X, Y, Z) between MVCT image taken after treatment and CT-simulation image are close to zero, the patient movement is small. When the mean values of movement of each direction for non-coplanar setup were compared with coplanar setup group, X-axis movement was decreased by 13%, but Y-axis and Z-axis movement were increased by 109% and 88%, respectively. Movements of Y-axis and Z-axis with non-coplanar setup were relatively greater than that of X-axis since a tilted head tended to slip down. The mean of X-axis movement of the group who used a mouthpiece was greater by 9.4% than the group

  6. Optimal pitching axis location of flapping wings for efficient hovering flight.

    Science.gov (United States)

    Wang, Q; Goosen, J F L; van Keulen, F

    2017-09-01

    Flapping wings can pitch passively about their pitching axes due to their flexibility, inertia, and aerodynamic loads. A shift in the pitching axis location can dynamically alter the aerodynamic loads, which in turn changes the passive pitching motion and the flight efficiency. Therefore, it is of great interest to investigate the optimal pitching axis for flapping wings to maximize the power efficiency during hovering flight. In this study, flapping wings are modeled as rigid plates with non-uniform mass distribution. The wing flexibility is represented by a linearly torsional spring at the wing root. A predictive quasi-steady aerodynamic model is used to evaluate the lift generated by such wings. Two extreme power consumption scenarios are modeled for hovering flight, i.e. the power consumed by a drive system with and without the capacity of kinetic energy recovery. For wings with different shapes, the optimal pitching axis location is found such that the cycle-averaged power consumption during hovering flight is minimized. Optimization results show that the optimal pitching axis is located between the leading edge and the mid-chord line, which shows close resemblance to insect wings. An optimal pitching axis can save up to 33% of power during hovering flight when compared to traditional wings used by most of flapping wing micro air vehicles (FWMAVs). Traditional wings typically use the straight leading edge as the pitching axis. With the optimized pitching axis, flapping wings show higher pitching amplitudes and start the pitching reversals in advance of the sweeping reversals. These phenomena lead to higher lift-to-drag ratios and, thus, explain the lower power consumption. In addition, the optimized pitching axis provides the drive system higher potential to recycle energy during the deceleration phases as compared to their counterparts. This observation underlines the particular importance of the wing pitching axis location for energy-efficient FWMAVs when

  7. A Method for Modeling of Floating Vertical Axis Wind Turbine

    DEFF Research Database (Denmark)

    Wang, Kai; Hansen, Martin Otto Laver; Moan, Torgeir

    2013-01-01

    It is of interest to investigate the potential advantages of floating vertical axis wind turbine (FVAWT) due to its economical installation and maintenance. A novel 5MW vertical axis wind turbine concept with a Darrieus rotor mounted on a semi-submersible support structure is proposed in this paper....... In order to assess the technical and economic feasibility of this novel concept, a comprehensive simulation tool for modeling of the floating vertical axis wind turbine is needed. This work presents the development of a coupled method for modeling of the dynamics of a floating vertical axis wind turbine....... This integrated dynamic model takes into account the wind inflow, aerodynamics, hydrodynamics, structural dynamics (wind turbine, floating platform and the mooring lines) and a generator control. This approach calculates dynamic equilibrium at each time step and takes account of the interaction between the rotor...

  8. Small Vertical Axis Wind Turbines: aerodynamics and starting behavior

    Directory of Open Access Journals (Sweden)

    Horia DUMITRESCU

    2013-12-01

    Full Text Available In urban areas the wind is very turbulent and unstable with fast changes in direction andvelocity. In these environments, the use of small vertical axis wind turbines (VAWT becomesincreasingly attractive due to several advantages over horizontal axis wind turbines (HAWT.However, such designs have received much less attention than the more common propeller-typedesigns and the understanding of same aspects of their operation remains, to this day, incomplete.This is particularly true of their starting characteristics. Indeed, same authors heuristically maintainthat they cannot start without external assistance. This paper reviews the cause of the inability of thelow solidity fixed pitch vertical axis wind turbines to self-start, and investigates the way ofovercoming this draw back.

  9. A local-circulation model for Darrieus vertical-axis wind turbines

    Science.gov (United States)

    Masse, B.

    1986-04-01

    A new computational model for the aerodynamics of the vertical-axis wind turbine is presented. Based on the local-circulation method generalized for curved blades, combined with a wake model for the vertical-axis wind turbine, it differs markedly from current models based on variations in the streamtube momentum and vortex models using the lifting-line theory. A computer code has been developed to calculate the loads and performance of the Darrieus vertical-axis wind turbine. The results show good agreement with experimental data and compare well with other methods.

  10. Tunable magnetic properties by interfacial manipulation of L1(0)-FePt perpendicular ultrathin film with island-like structures.

    Science.gov (United States)

    Feng, C; Wang, S G; Yang, M Y; Zhang, E; Zhan, Q; Jiang, Y; Li, B H; Yu, G H

    2012-02-01

    Based on interfacial manipulation of the MgO single crystal substrate and non-magnetic AIN compound, a L1(0)-FePt perpendicular ultrathin film with the structure of MgO/FePt-AIN/Ta was designed, prepared, and investigated. The film is comprised of L1(0)-FePt "magnetic islands," which exhibits a perpendicular magnetic anisotropy (PMA), tunable coercivity (Hc), and interparticle exchange coupling (IEC). The MgO substrate promotes PMA of the film because of interfacial control of the FePt lattice orientation. The AIN compound is doped to increase the difference of surface energy between FePt layer and MgO substrate and to suppress the growth of FePt grains, which takes control of island growth mode of FePt atoms. The AIN compound also acts as isolator of L1(0)-FePt islands to pin the sites of FePt domains, resulting in the tunability of Hc and IEC of the films.

  11. The Performance Characteristics of a Closed Loop, One Axis ...

    African Journals Online (AJOL)

    This paper presents a closed loop one axis solar tracking device of the polar axis type, which achieves an accurate tracking of the sun with a steady state error of less, than 2%. This prototype uses a photo-sensing system to generate an error signal. This error signal switches on a relay, which actuates an electromechanical ...

  12. Perpendicular Structure Formation of Block Copolymer Thin Films during Thermal Solvent Vapor Annealing: Solvent and Thickness Effects

    Directory of Open Access Journals (Sweden)

    Qiuyan Yang

    2017-10-01

    Full Text Available Solvent vapor annealing of block copolymer (BCP thin films can produce a range of interesting morphologies, especially when the perpendicular orientation of micro-domains with respect to the substrate plays a role. This, for instance, allows BCP thin films to serve as useful templates for nanolithography and hybrid materials preparation. However, precise control of the arising morphologies is essential, but in most cases difficult to achieve. In this work, we investigated the solvent and thickness effects on the morphology of poly(styrene-b-2 vinyl pyridine (PS-b-P2VP thin films with a film thickness range from 0.4 L0 up to 0.8 L0. Ordered perpendicular structures were achieved. One of the main merits of our work is that the phase behavior of the ultra-high molecular weight BCP thin films, which hold a 100-nm sized domain distance, can be easily monitored via current available techniques, such as scanning electron microscope (SEM, atomic force microscope (AFM, and transmission electron microscope (TEM. Systematic monitoring of the self-assembly behavior during solvent vapor annealing can thus provide an experimental guideline for the optimization of processing conditions of related BCP films systems.

  13. Two-stream instabilities from the lower-hybrid frequency to the electron cyclotron frequency: application to the front of quasi-perpendicular shocks

    Directory of Open Access Journals (Sweden)

    L. Muschietti

    2017-09-01

    Full Text Available Quasi-perpendicular supercritical shocks are characterized by the presence of a magnetic foot due to the accumulation of a fraction of the incoming ions that is reflected by the shock front. There, three different plasma populations coexist (incoming ion core, reflected ion beam, electrons and can excite various two-stream instabilities (TSIs owing to their relative drifts. These instabilities represent local sources of turbulence with a wide frequency range extending from the lower hybrid to the electron cyclotron. Their linear features are analyzed by means of both a dispersion study and numerical PIC simulations. Three main types of TSI and correspondingly excited waves are identified: i. Oblique whistlers due to the (so-called fast relative drift between reflected ions/electrons; the waves propagate toward upstream away from the shock front at a strongly oblique angle (θ ∼ 50° to the ambient magnetic field Bo, have frequencies a few times the lower hybrid, and have wavelengths a fraction of the ion inertia length c∕ωpi. ii. Quasi-perpendicular whistlers due to the (so-called slow relative drift between incoming ions/electrons; the waves propagate toward the shock ramp at an angle θ a few degrees off 90°, have frequencies around the lower hybrid, and have wavelengths several times the electron inertia length c∕ωpe. iii. Extended Bernstein waves which also propagate in the quasi-perpendicular domain, yet are due to the (so-called fast relative drift between reflected ions/electrons; the instability is an extension of the electron cyclotron drift instability (normally strictly perpendicular and electrostatic and produces waves with a magnetic component which have frequencies close to the electron cyclotron as well as wavelengths close to the electron gyroradius and which propagate toward upstream. Present results are compared with previous works in order to stress some features not previously analyzed and to define a more

  14. Investigation of nanocrystalline thin cobalt films thermally evaporated on Si(100) substrates

    Energy Technology Data Exchange (ETDEWEB)

    Kozłowski, W., E-mail: wkozl@std2.phys.uni.lodz.pl [Department of Solid State Physics, Faculty of Physics and Applied Informatics, University of Łódź, Pomorska 149/153, 90-236 Łódź (Poland); Balcerski, J.; Szmaja, W. [Department of Solid State Physics, Faculty of Physics and Applied Informatics, University of Łódź, Pomorska 149/153, 90-236 Łódź (Poland); Piwoński, I. [Department of Materials Technology and Chemistry, Faculty of Chemistry, University of Łódź, Pomorska 163, 90-236 Łódź (Poland); Batory, D. [Institute of Materials Science and Engineering, Łódź University of Technology, Stefanowskiego 1/15, 90-924 Łódź (Poland); Miękoś, E. [Department of Inorganic and Analytical Chemistry, Faculty of Chemistry, University of Łódź, Tamka 12, 91-403 Łódź (Poland); and others

    2017-03-15

    We have made a quantitative study of the morphological and magnetic domain structures of 100 nm thick nanocrystalline cobalt films thermally evaporated on naturally oxidized Si(100) substrates. The morphological structure is composed of densely packed grains with the average grain size (35.6±0.8) nm. The grains exhibit no geometric alignment and no preferred elongation on the film surface. In the direction perpendicular to the film surface, the grains are aligned in columns. The films crystallize mainly in the hexagonal close-packed phase of cobalt and possess a crystallographic texture with the hexagonal axis perpendicular to the film surface. The magnetic domain structure consists of domains forming a maze stripe pattern with the average domain size (102±6) nm. The domains have their magnetizations oriented almost perpendicularly to the film surface. The domain wall energy, the domain wall thickness and the critical diameter for single-domain particle were determined. - Highlights: • 100 nm thick nanocrystalline cobalt films on Si(100) were studied quantitatively. • The grains are densely packed and possess the average size (35.6±0.8) nm. • The films have a texture with the hexagonal axis perpendicular to the film surface. • The magnetic domains form a maze stripe pattern with the average size (102±6) nm. • The domains are magnetized almost perpendicularly to the film surface.

  15. Microstructure of titanium deformed by warm extrusion with forward- backward rotating die

    International Nuclear Information System (INIS)

    Sztwiertnia, K; Morawiec, A; Bieda, M; Kawałko, J

    2014-01-01

    The principal KoBo device is a press with a forward-backward rotating die, enabling the extrusion of ingots under conditions of constant destabilization of their substructure. Polycrystalline grade 2 titanium was subjected to warm KoBo type extrusion. Microstructure of the material was investigated by means of Electron Backscatter Diffraction (EBSD) in the scanning electron microscope. It clearly shows deformation-induced grain fragmentation. The EBSD maps reveal heterogeneous microstructure built of ribbons curled about the extrusion direction (ED) and some equiaxed or cigar-like grains. Sizes of grains vary in the range 70 – 1500 nm for the minor axis and 350 – 20000 nm for the major axis. The material has a relatively sharp nearly axial texture with the <0001> axis perpendicular to ED. In misorientation angle distribution, besides the peak at low angle boundaries, there are three other peaks at about: 29.7deg, 89.7deg and 93.2deg. They do not correspond to any twin boundaries or low Σ coincidence site lattice misorientations

  16. Dietary Manipulations That Induce Ketosis Activate the HPA Axis in Male Rats and Mice: A Potential Role for Fibroblast Growth Factor-21.

    Science.gov (United States)

    Ryan, Karen K; Packard, Amy E B; Larson, Karlton R; Stout, Jayna; Fourman, Sarah M; Thompson, Abigail M K; Ludwick, Kristen; Habegger, Kirk M; Stemmer, Kerstin; Itoh, Nobuyuki; Perez-Tilve, Diego; Tschöp, Matthias H; Seeley, Randy J; Ulrich-Lai, Yvonne M

    2018-01-01

    In response to an acute threat to homeostasis or well-being, the hypothalamic-pituitary-adrenocortical (HPA) axis is engaged. A major outcome of this HPA axis activation is the mobilization of stored energy, to fuel an appropriate behavioral and/or physiological response to the perceived threat. Importantly, the extent of HPA axis activity is thought to be modulated by an individual's nutritional environment. In this study, we report that nutritional manipulations signaling a relative depletion of dietary carbohydrates, thereby inducing nutritional ketosis, acutely and chronically activate the HPA axis. Male rats and mice maintained on a low-carbohydrate high-fat ketogenic diet (KD) exhibited canonical markers of chronic stress, including increased basal and stress-evoked plasma corticosterone, increased adrenal sensitivity to adrenocorticotropin hormone, increased stress-evoked c-Fos immunolabeling in the paraventricular nucleus of the hypothalamus, and thymic atrophy, an indicator of chronic glucocorticoid exposure. Moreover, acutely feeding medium-chain triglycerides (MCTs) to rapidly induce ketosis among chow-fed male rats and mice also acutely increased HPA axis activity. Lastly, and consistent with a growing literature that characterizes the hepatokine fibroblast growth factor-21 (FGF21) as both a marker of the ketotic state and as a key metabolic stress hormone, the HPA response to both KD and MCTs was significantly blunted among mice lacking FGF21. We conclude that dietary manipulations that induce ketosis lead to increased HPA axis tone, and that the hepatokine FGF21 may play an important role to facilitate this effect. Copyright © 2018 Endocrine Society.

  17. A Numerical Study on a Vertical-Axis Wind Turbine with Inclined Arms

    Directory of Open Access Journals (Sweden)

    Agostino De Marco

    2014-01-01

    Full Text Available This work focuses on a particular type of vertical-axis wind turbine, in which a number of inclined arms with airfoil-shaped cross-sections are mounted to connect the principal blades to their hub. While the majority of the known studies on vertical-axis turbines is devoted to the role of principal blades, in most of the cases without taking into account other parts of the wind turbine, the objective of this work is to investigate the effect of uncommon arm geometries, such as the inclined arms. The inclined arms are known to have a potentially beneficial role in the power extraction from the wind current but, due to the complexity of the phenomena, the investigation on aerodynamics of this type of turbine is often impossible through analytical models, such as blade-element momentum theory. It turns out that adequate studies can only be carried out by wind tunnel experiments or CFD simulations. This work presents a methodical CFD study on how inclined arms can be used on a selected wind turbine configuration to harvest additional power from the wind. The turbine configuration, geometry, and some fundamental definitions are introduced first. Then an in-depth CFD analysis is presented and discussed.

  18. Magnetic ground and remanent states of synthetic metamagnets with perpendicular anisotropy

    International Nuclear Information System (INIS)

    Kiselev, N S; Roessler, U K; Bogdanov, A N; Hellwig, O

    2011-01-01

    In this work, we summarize our theoretical results within a phenomenological micromagnetic approach for magnetic ground state and nonequilibrium states as topological magnetic defects in multilayers with strong perpendicular anisotropy and antiferromagnetic (AF) interlayer exchange coupling (IEC), e.g. [Co/Pt(Pd)]/Ru(Ir, NiO). We give detailed analysis of our model together with the most representative results which elucidate common features of such systems. We discuss phase diagrams of the magnetic ground state, and compare solutions of our model with experimental data. A model to assess the stability of so-called tiger tail patterns is presented. It is found that these modulated topological defect cannot be stabilized by an interplay between magnetostatic and IEC energies only. It is argued that tiger tail patterns arise as nuclei of ferro-stripe structure in AF domain walls and that they are stabilized by domain wall pinning.

  19. Relaxation dynamics of magnetization transitions in synthetic antiferromagnet with perpendicular anisotropy

    Science.gov (United States)

    Talantsev, A.; Lu, Y.; Fache, T.; Lavanant, M.; Hamadeh, A.; Aristov, A.; Koplak, O.; Morgunov, R.; Mangin, S.

    2018-04-01

    Two synthetic antiferromagnet bilayer systems with strong perpendicular anisotropy CoFeB/Ta/CoFeB and Pt/Co/Ir/Co/Pt have been grown using sputtering techniques. For both systems two types of magnetization transitions have been studied. The first one concerns transitions from a state where magnetizations of the two magnetic layers are parallel (P state) to a state where magnetizations of the two layers are aligned antiparallel (AP state). The second one concerns transitions between the two possible antiparallel alignments (AP+  to AP-). For both systems and both transitions after-effect measurements can be understood in the frame of nucleation—propagation model. Time derivative analysis of magnetic relaxation curves and mapping of the first order reversal curves at different temperature allowed us to demonstrate the presence of different pinning centers, which number can be controlled by magnetic field and temperature.

  20. Electrotonic Coupling in the Pituitary Supports the Hypothalamic-Pituitary-Gonadal Axis in a Sex Specific Manner

    Directory of Open Access Journals (Sweden)

    Christina Göngrich

    2016-08-01

    Full Text Available Gap junctions are present in many cell types throughout the animal kingdom and allow fast intercellular electrical and chemical communication between neighboring cells. Connexin-36 (Cx36, the major neuronal gap junction protein, synchronizes cellular activity in the brain, but also in other organs. Here we identify a sex-specific role for Cx36 within the hypothalamic-pituitary-gonadal (HPG axis at the level of the anterior pituitary gland (AP. We show that Cx36 is expressed in gonadotropes of the AP sustaining their synchronous activity. Cx36 ablation affects the entire downstream HPG axis in females, but not in males. We demonstrate that Cx36-mediated coupling between gonadotropes in the AP supports gonadotropin-releasing hormone-induced secretion of luteinizing hormone. Furthermore, we provide evidence for negative feedback regulation of Cx36 expression in the AP by estradiol. We thus conclude that hormonally-controlled plasticity of gap junction communication at the level of the AP constitutes an additional mechanism affecting female reproduction.

  1. Arch-Axis Coefficient Optimization of Long-Span Deck-Type Concrete-Filled Steel Tubular Arch Bridge

    Science.gov (United States)

    Liu, Q. J.; Wan, S.; Liu, H. C.

    2017-11-01

    This paper is based on Nanpuxi super major bridge which is under construction and starts from Wencheng Zhejiang province to Taishun highway. A finite element model of the whole bridge is constructed using Midas Civil finite element software. The most adverse load combination in the specification is taken into consideration to determine the method of calculating the arch-axis coefficient of long-span deck-type concrete-filled steel tubular arch bridge. By doing this, this paper aims at providing references for similar engineering projects.

  2. Flight Test of a Propulsion-Based Emergency Control System on the MD-11 Airplane with Emphasis on the Lateral Axis

    Science.gov (United States)

    Burken, John J.; Burcham, Frank W., Jr.; Maine, Trindel A.; Feather, John; Goldthorpe, Steven; Kahler, Jeffrey A.

    1996-01-01

    A large, civilian, multi-engine transport MD-11 airplane control system was recently modified to perform as an emergency backup controller using engine thrust only. The emergency backup system, referred to as the propulsion-controlled aircraft (PCA) system, would be used if a major primary flight control system fails. To allow for longitudinal and lateral-directional control, the PCA system requires at least two engines and is implemented through software modifications. A flight-test program was conducted to evaluate the PCA system high-altitude flying characteristics and to demonstrate its capacity to perform safe landings. The cruise flight conditions, several low approaches and one landing without any aerodynamic flight control surface movement, were demonstrated. This paper presents results that show satisfactory performance of the PCA system in the longitudinal axis. Test results indicate that the lateral-directional axis of the system performed well at high attitude but was sluggish and prone to thermal upsets during landing approaches. Flight-test experiences and test techniques are also discussed with emphasis on the lateral-directional axis because of the difficulties encountered in flight test.

  3. Space cutter compensation method for five-axis nonuniform rational basis spline machining

    Directory of Open Access Journals (Sweden)

    Yanyu Ding

    2015-07-01

    Full Text Available In view of the good machining performance of traditional three-axis nonuniform rational basis spline interpolation and the space cutter compensation issue in multi-axis machining, this article presents a triple nonuniform rational basis spline five-axis interpolation method, which uses three nonuniform rational basis spline curves to describe cutter center location, cutter axis vector, and cutter contact point trajectory, respectively. The relative position of the cutter and workpiece is calculated under the workpiece coordinate system, and the cutter machining trajectory can be described precisely and smoothly using this method. The three nonuniform rational basis spline curves are transformed into a 12-dimentional Bézier curve to carry out discretization during the discrete process. With the cutter contact point trajectory as the precision control condition, the discretization is fast. As for different cutters and corners, the complete description method of space cutter compensation vector is presented in this article. Finally, the five-axis nonuniform rational basis spline machining method is further verified in a two-turntable five-axis machine.

  4. The development and testing of a novel cross axis wind turbine

    Science.gov (United States)

    Chong, W. T.; Muzammil, W. K.; Gwani, M.; Wong, K. H.; Fazlizan, A.; Wang, C. T.; Poh, S. C.

    2016-06-01

    A novel cross axis wind turbine (CAWT) which comprises of a cross axis blades arrangement was presented and investigated experimentally. The CAWT is a new type of wind turbine that extracts wind energy from airflow coming from the horizontal and vertical directions. The wind turbine consists of three vertical blades and six horizontal blades arranged in a cross axis orientation. Hubs in the middle of the CAWT link the horizontal and vertical blades through connectors to form the CAWT. The study used a 45° deflector to guide the oncoming airflow upward (vertical wind direction). The results from the study showed that the CAWT produced significant improvements in power output and rotational speed performance compared to a conventional straight-bladed vertical axis wind turbine (VAWT).

  5. Ion Dynamics at Shocks: Ion Reflection and Beam Formation at Quasi-perpendicular Shocks

    International Nuclear Information System (INIS)

    Kucharek, Harald; Moebius, Eberhard

    2005-01-01

    The physics of collisionless shocks is controlled by the ion dynamics. The generation of gyrating ions by reflection as well as the formation of field-aligned ion beams are essential parts of this dynamic. On the one hand reflection is most likely the first interaction of ions with the shock before they undergo the downstream thermalization process. On the other hand field-aligned ion beams, predominately found at the quasi-perpendicular bow shock, propagate into the distant foreshock region and may create wave activity. We revisit ion reflection, the source and basic production mechanism of field-aligned ion beams, by using multi-spacecraft measurements and contrast these observations with existing theories. Finally, we propose an alternative production mechanism

  6. Barrier breakdown mechanism in nano-scale perpendicular magnetic tunnel junctions with ultrathin MgO barrier

    Science.gov (United States)

    Lv, Hua; Leitao, Diana C.; Hou, Zhiwei; Freitas, Paulo P.; Cardoso, Susana; Kämpfe, Thomas; Müller, Johannes; Langer, Juergen; Wrona, Jerzy

    2018-05-01

    Recently, the perpendicular magnetic tunnel junctions (p-MTJs) arouse great interest because of its unique features in the application of spin-transfer-torque magnetoresistive random access memory (STT-MRAM), such as low switching current density, good thermal stability and high access speed. In this paper, we investigated current induced switching (CIS) in ultrathin MgO barrier p-MTJs with dimension down to 50 nm. We obtained a CIS perpendicular tunnel magnetoresistance (p-TMR) of 123.9% and 7.0 Ω.μm2 resistance area product (RA) with a critical switching density of 1.4×1010 A/m2 in a 300 nm diameter junction. We observe that the extrinsic breakdown mechanism dominates, since the resistance of our p-MTJs decreases gradually with the increasing current. From the statistical analysis of differently sized p-MTJs, we observe that the breakdown voltage (Vb) of 1.4 V is 2 times the switching voltage (Vs) of 0.7 V and the breakdown process exhibits two different breakdown states, unsteady and steady state. Using Simmons' model, we find that the steady state is related with the barrier height of the MgO layer. Furthermore, our study suggests a more efficient method to evaluate the MTJ stability under high bias rather than measuring Vb. In conclusion, we developed well performant p-MTJs for the use in STT-MRAM and demonstrate the mechanism and control of breakdown in nano-scale ultrathin MgO barrier p-MTJs.

  7. Precision grip responses to unexpected rotational perturbations scale with axis of rotation.

    Science.gov (United States)

    De Gregorio, Michael; Santos, Veronica J

    2013-04-05

    It has been established that rapid, pulse-like increases in precision grip forces ("catch-up responses") are elicited by unexpected translational perturbations and that response latency and strength scale according to the direction of linear slip relative to the hand as well as gravity. To determine if catch-up responses are elicited by unexpected rotational perturbations and are strength-, axis-, and/or direction-dependent, we imposed step torque loads about each of two axes which were defined relative to the subject's hand: the distal-proximal axis away from and towards the subject's palm, and the grip axis which connects the two fingertips. Precision grip responses were dominated initially by passive mechanics and then by active, unimodal catch-up responses. First dorsal interosseous activity, marking the start of the catch-up response, began 71-89 ms after the onset of perturbation. The onset latency, shape, and duration (217-231 ms) of the catch-up response were not affected by the axis, direction, or magnitude of the rotational perturbation, while strength was scaled by axis of rotation and slip conditions. Rotations about the grip axis that tilted the object away from the palm and induced rotational slip elicited stronger catch-up responses than rotations about the distal-proximal axis that twisted the object between the digits. To our knowledge, this study is the first to investigate grip responses to unexpected torque loads and to show characteristic, yet axis-dependent, catch-up responses for conditions other than pure linear slip. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Coupled granular/continuous medium for thermally stable perpendicular magnetic recording

    International Nuclear Information System (INIS)

    Sonobe, Y.; Weller, D.; Ikeda, Y.; Takano, K.; Schabes, M.E.; Zeltzer, G.; Do, H.; Yen, B.K.; Best, M.E.

    2001-01-01

    We studied coupled granular/continuous (CGC) perpendicular media consisting of a continuous multilayer structure and a granular layer. The addition of Co/Pt multilayers decreased the nucleation field from 200 to -1800 Oe and increased the squareness from 0.9 to 1.0. The moment decay at room temperature was significantly reduced from -4.8% to -0.05% per decade. At elevated temperatures, strong exchange coupling between a granular layer and a continuous layer is needed for thermal stability. The exchange-coupled continuous layer reduces thermal demagnetization as it effectively increases the grain size, tightens the grain distribution, and prevents the reversal of individual grains. Magnetic Force Microscope image showed a larger magnetic cluster size for the CGC structure. Compared to the CoCr 18 Pt 12 medium, the CGC medium had 2.3 dB higher output. However, the noise for the CGC medium increased with the recording density, while the noise for the CoCr 18 Pt 12 medium remained constant from 4 to 15 kfc/mm. Further optimization and noise reduction are still required for future high density recording

  9. Effect of soft underlayer magnetic anisotropy on perpendicular recording process

    International Nuclear Information System (INIS)

    Lim, C.K.; Kim, E.S.; Yoon, S.Y.; Kong, S.H.; Lee, H.S.; Oh, H.S.; Kim, Y.S.

    2007-01-01

    The presence of the soft magnetic underlayer (SUL) in perpendicular magnetic recording (PMR) media is essential for the application. It is commonly understood that the SUL provides the return flux path and enhances the writing field by enhancing the recording field from the write pole. However, SUL increases the magnetic noise during the read back process due to magnetic domain walls in the SUL. Hence, it is common to grow SUL with large uniaxial or unidirectional magnetic anisotropy field (H k ) to reduce domain wall noise. In this paper, we explore the effect of increasing SUL H k on the recording process. We studied this effect by using the finite element micromagnetic simulation. Our simulation results show that the contribution of SUL to the writing field amplitude is reduced with increasing H k . This reduction in magnetic field from high H k SUL actually improves the recording performance due to the better field gradient at SUL. The simulation results are qualitatively consistent with the actual experimental data obtained from the Guzik measurement

  10. Coupled granular/continuous medium for thermally stable perpendicular magnetic recording

    Science.gov (United States)

    Sonobe, Y.; Weller, D.; Ikeda, Y.; Takano, K.; Schabes, M. E.; Zeltzer, G.; Do, H.; Yen, B. K.; Best, M. E.

    2001-10-01

    We studied coupled granular/continuous (CGC) perpendicular media consisting of a continuous multilayer structure and a granular layer. The addition of Co/Pt multilayers decreased the nucleation field from 200 to -1800 Oe and increased the squareness from 0.9 to 1.0. The moment decay at room temperature was significantly reduced from -4.8% to -0.05% per decade. At elevated temperatures, strong exchange coupling between a granular layer and a continuous layer is needed for thermal stability. The exchange-coupled continuous layer reduces thermal demagnetization as it effectively increases the grain size, tightens the grain distribution, and prevents the reversal of individual grains. Magnetic Force Microscope image showed a larger magnetic cluster size for the CGC structure. Compared to the CoCr 18Pt 12 medium, the CGC medium had 2.3 dB higher output. However, the noise for the CGC medium increased with the recording density, while the noise for the CoCr 18Pt 12 medium remained constant from 4 to 15 kfc/mm. Further optimization and noise reduction are still required for future high density recording.

  11. Lake Malawi cichlid evolution along a benthic/limnetic axis.

    Science.gov (United States)

    Hulsey, C D; Roberts, R J; Loh, Y-H E; Rupp, M F; Streelman, J T

    2013-07-01

    Divergence along a benthic to limnetic habitat axis is ubiquitous in aquatic systems. However, this type of habitat divergence has largely been examined in low diversity, high latitude lake systems. In this study, we examined the importance of benthic and limnetic divergence within the incredibly species-rich radiation of Lake Malawi cichlid fishes. Using novel phylogenetic reconstructions, we provided a series of hypotheses regarding the evolutionary relationships among 24 benthic and limnetic species that suggests divergence along this axis has occurred multiple times within Lake Malawi cichlids. Because pectoral fin morphology is often associated with divergence along this habitat axis in other fish groups, we investigated divergence in pectoral fin muscles in these benthic and limnetic cichlid species. We showed that the eight pectoral fin muscles and fin area generally tended to evolve in a tightly correlated manner in the Lake Malawi cichlids. Additionally, we found that larger pectoral fin muscles are strongly associated with the independent evolution of the benthic feeding habit across this group of fish. Evolutionary specialization along a benthic/limnetic axis has occurred multiple times within this tropical lake radiation and has produced repeated convergent matching between exploitation of water column habitats and locomotory morphology.

  12. A four-axis hand controller for helicopter flight control

    Science.gov (United States)

    Demaio, Joe

    1993-01-01

    A proof-of-concept hand controller for controlling lateral and longitudinal cyclic pitch, collective pitch and tail rotor thrust was developed. The purpose of the work was to address problems of operator fatigue, poor proprioceptive feedback and cross-coupling of axes associated with many four-axis controller designs. The present design is an attempt to reduce cross-coupling to a level that can be controlled with breakout force, rather than to eliminate it entirely. The cascaded design placed lateral and longitudinal cyclic in their normal configuration. Tail rotor thrust was placed atop the cyclic controller. A left/right twisting motion with the wrist made the control input. The axis of rotation was canted outboard (clockwise) to minimize cross-coupling with the cyclic pitch axis. The collective control was a twist grip, like a motorcycle throttle. Measurement of the amount of cross-coupling involved in pure, single-axis inputs showed cross coupling under 10 percent of full deflection for all axes. This small amount of cross-coupling could be further reduced with better damping and force gradient control. Fatigue was not found to be a problem, and proprioceptive feedback was adequate for all flight tasks executed.

  13. Late Presentation of a Type III Axis Fracture with Spondyloptosis

    Science.gov (United States)

    Jayakumar, Prakash; Choi, David; Casey, Adrian

    2008-01-01

    A 58-year-old man presented with an undiagnosed Effendi type III classification fracture and spondyloptosis of the axis with remarkably normal neurology. We discuss his surgery 4 years since the initial injury, and the presentation, features and management of fractures of the axis. PMID:18430325

  14. New capacitive low-g triaxial accelerometer with low cross-axis sensitivity

    International Nuclear Information System (INIS)

    Hsu, Yu-Wen; Chen, Jen-Yi; Chien, Hsin-Tang; Chen, Sheah; Lin, Shih-Ting; Liao, Lu-Po

    2010-01-01

    This work describes a compact accelerometer, which integrates three spring-proof mass systems into a single structure to sense triaxial motion. It has a size of 1.3 × 1.28 mm 2 and an operating range of ±1 g. Silicon-on-glass (SOG) micromachining and deep reactive-ion etching (DRIE)-based process are adopted to fabricate this accelerometer with a high-aspect-ratio sensing structure. The accelerometer has an excellent z-axis output sensitivity of 1.434 V g −1 and a high resolution of 49 µg Hz −1/2 . The sensitivity and minimum cross-axis sensitivity of the x-axis in-plane accelerometer are 1.442 V g −1 and 0.03% and those of the y-axis accelerometer are 1.241 V g −1 and 0.21%, respectively. The new in-plane and out-of-plane accelerometer design exhibits high cross-axis sensitivity immunity, high sensitivity and high linearity suggesting that the triaxial accelerometer has the potential for use in future applications in consumer goods and the cellular phone marketþ

  15. Quasi-Rayleigh waves in transversely isotropic half-space with inclined axis of symmetry

    International Nuclear Information System (INIS)

    Yanovskaya, T.B.; Savina, L.S.

    2003-09-01

    A method for determination of characteristics of quasi-Rayleigh (qR) wave in a transversely isotropic homogeneous half-space with inclined axis of symmetry is outlined. The solution is obtained as a superposition of qP, qSV and qSH waves, and surface wave velocity is determined from the boundary conditions at the free surface and at infinity, as in the case of Rayleigh wave in isotropic half-space. Though the theory is simple enough, a numerical procedure for the calculation of surface wave velocity presents some difficulties. The difficulty is conditioned by necessity to calculate complex roots of a non-linear equation, which in turn contains functions determined as roots of nonlinear equations with complex coefficients. Numerical analysis shows that roots of the equation corresponding to the boundary conditions do not exist in the whole domain of azimuths and inclinations of the symmetry axis. The domain of existence of qR wave depends on the ratio of the elastic parameters: for some strongly anisotropic models the wave cannot exist at all. For some angles of inclination qR wave velocities deviate from those calculated on the basis of the perturbation method valid for weak anisotropy, though they have the same tendency of variation with azimuth. The phase of qR wave varies with depth unlike Rayleigh wave in isotropic half-space. Unlike Rayleigh wave in isotropic half-space, qR wave has three components - vertical, radial and transverse. Particle motion in horizontal plane is elliptic. Direction of the major axis of the ellipsis coincide with the direction of propagation only in azimuths 0 deg. (180 deg.) and 90 deg. (270 deg.). (author)

  16. Inequalities for majorizing analytic functions and their applications to rational trigonometric functions and polynomials

    International Nuclear Information System (INIS)

    Olesov, A V

    2014-01-01

    New inequalities are established for analytic functions satisfying Meiman's majorization conditions. Estimates for values of and differential inequalities involving rational trigonometric functions with an integer majorant on an interval of length less than the period and with prescribed poles which are symmetrically positioned relative to the real axis, as well as differential inequalities for trigonometric polynomials in some classes, are given as applications. These results improve several theorems due to Meiman, Genchev, Smirnov and Rusak. Bibliography: 27 titles

  17. Optical Three-Axis Tactile Sensor for Robotic Fingers

    OpenAIRE

    Ohka, Masahiro; Takata, Jumpei; Kobayashi, Hiroaki; Suzuki, Hirofumi; Morisawa, Nobuyuki; Yussof, Hanafiah Bin

    2008-01-01

    A new three-axis tactile sensor to be mounted on multi-fingered hands is developed based on the principle of an optical waveguide-type tactile sensor comprised of an acrylic hemispherical dome, a light source, an array of rubber sensing elements, and a CCD camera. The sensing element of the present tactile sensor includes one columnar feeler and eight conical feelers. A three-axis force applied to the tip of the sensing element is detected by the contact areas of the conical feelers, which ma...

  18. Design and analysis of a semi-submersible vertical axis wind turbine

    OpenAIRE

    Siddique, Muhammad Abu Zafar

    2017-01-01

    Wind energy are deployed by two types of wind turbines. They are Horizontal Axis Wind Turbine (HAWT) and Vertical Axis Wind Turbine (VAWT), classified according to their axis of rotation. In recent years, offshore wind energy playing a vital role in the wind turbine industry due to high intensity of air, less turbulent and comparatively clean and easily employed in large area which is difficult to manage for onshore or near-shore. The advantages of HAWTs are now facing different challenge in ...

  19. Cortical microtubule nucleation can organise the cytoskeleton of Drosophila oocytes to define the anteroposterior axis

    Science.gov (United States)

    Khuc Trong, Philipp; Doerflinger, Hélène; Dunkel, Jörn; St Johnston, Daniel; Goldstein, Raymond E

    2015-01-01

    Many cells contain non-centrosomal arrays of microtubules (MTs), but the assembly, organisation and function of these arrays are poorly understood. We present the first theoretical model for the non-centrosomal MT cytoskeleton in Drosophila oocytes, in which bicoid and oskar mRNAs become localised to establish the anterior-posterior body axis. Constrained by experimental measurements, the model shows that a simple gradient of cortical MT nucleation is sufficient to reproduce the observed MT distribution, cytoplasmic flow patterns and localisation of oskar and naive bicoid mRNAs. Our simulations exclude a major role for cytoplasmic flows in localisation and reveal an organisation of the MT cytoskeleton that is more ordered than previously thought. Furthermore, modulating cortical MT nucleation induces a bifurcation in cytoskeletal organisation that accounts for the phenotypes of polarity mutants. Thus, our three-dimensional model explains many features of the MT network and highlights the importance of differential cortical MT nucleation for axis formation. DOI: http://dx.doi.org/10.7554/eLife.06088.001 PMID:26406117

  20. Microwave properties of Ni-based ferromagnetic inverse opals

    Science.gov (United States)

    Kostylev, M.; Stashkevich, A. A.; Roussigné, Y.; Grigoryeva, N. A.; Mistonov, A. A.; Menzel, D.; Sapoletova, N. A.; Napolskii, K. S.; Eliseev, A. A.; Lukashin, A. V.; Grigoriev, S. V.; Samarin, S. N.

    2012-11-01

    Investigations of microwave properties of Ni-based inverse ferromagnetic opal-like film with the [111] axis of the fcc structure along the normal direction to the film have been carried out in the 2-18 GHz frequency band. We observed multiple spin wave resonances for the magnetic field applied perpendicular to the film, i.e., along the [111] axis of this artificial crystal. For the field applied in the film plane, a broad band of microwave absorption is observed, which does not contain a fine structure. The field ranges of the responses observed are quite different for these two magnetization directions. This suggests a collective magnetic ground state or shape anisotropy and collective microwave dynamics for this foam-like material. This result is in agreement with SQUID measurements of hysteresis loops for the material. Two different models for this collective behavior are suggested that satisfactorily explain the major experimental results.