120 research outputs found
Circular Dichroism in Cu Resonant Auger Electron Diffraction
Upon a core level excitation by circularly polarized light (CPL), the angular momentum of light, i.e. helicity, is transferred to the emitted photoelectron. This phenomenon can be confirmed by the parallax shift measurement of the forward focusing peak (FFP) direction in a stereograph of the atomic arrangement. The angular momentum of the emitted photoelectron is the sum of CPL helicity and the magnetic quantum number (MQN) of the initial state that define the quantum number of the core hole final state. The core hole may decay via Auger electron emission, where in this two electron process the angular momentum has to be conserved as well. Starting from a given core hole, different Auger decay channels with different final state energies and angular momenta of the emitted Auger electrons may be populated. Here we report the observation and formulation of the angular momentum transfer of light to Auger electrons, instead of photoelectrons. We measured photoelectron and Auger electron intensity angular distributions from Cu(111) and Cu(001) surfaces as a function of photon energy and photoelectron kinetic energy. By combining Auger electron spectroscopy with the FFP shift measurements at absorption threshold, element- and MQN-specific hole states can be generated in the valence band
Gender and Japan-Korea Differences in Psychological Characteristics through DIPCA and POMS for All Japan Wheelchair Basketball Atheletes
Although previous studies investigating physical performance and biomechanics in wheelchair-bound athletes were reported, few studies have characterized the psychological state of these athletes. This study investigated differences in psychological characteristics among 37 wheelchair-bound athletes (Japanese males, n=11; Japanese females, n=9; Korean males, n=17). All subjects belonged to their own national teams for disabled wheelchair basketball. All subjects completed both the Diagnostic Inventory of Psychological-Competitive Ability for Athletes (DIPCA) and the Profile Of Mood States (POMS). Statictics analysis of DIPCA showed that the psychological competitive abilities in the Japanese males were significantly better than those in the Korean males in this series. However. the scores on POMS did not show significant differences between the Japanese and Korean males, expect for the score for "anger". Neither DIPCA nor POMS showed any significant differences with regard to gender. Above all, we conclude that the psychological differences between Japanese and Koreans reflected the outcomes of international competitions and these there was no gender difference in psychological characteristics
Fermi level tuning of Ag-doped Bi2Se3 topological insulator
The temperature dependence of the resistivity (rho) of Ag-doped Bi2Se3 (AgxBi2-xSe3) shows insulating behavior above 35 K, but below 35 K, rho suddenly decreases with decreasing temperature, in contrast to the metallic behavior for non-doped Bi2Se3 at 1.5-300 K. This significant change in transport properties from metallic behavior clearly shows that the Ag doping of Bi2Se3 can effectively tune the Fermi level downward. The Hall effect measurement shows that carrier is still electron in AgxBi2-xSe3 and the electron density changes with temperature to reasonably explain the transport properties. Furthermore, the positive gating of AgxBi2-xSe3 provides metallic behavior that is similar to that of non-doped Bi2Se3, indicating a successful upward tuning of the Fermi level
A Genome-Wide Association Analysis Identified a Novel Susceptible Locus for Pathological Myopia at 11q24.1
Myopia is one of the most common ocular disorders worldwide. Pathological myopia, also called high myopia, comprises 1% to 5% of the general population and is one of the leading causes of legal blindness in developed countries. To identify genetic determinants associated with pathological myopia in Japanese, we conducted a genome-wide association study, analyzing 411,777 SNPs with 830 cases and 1,911 general population controls in a two-stage design (297 cases and 934 controls in the first stage and 533 cases and 977 controls in the second stage). We selected 22 SNPs that showed P-values smaller than 10−4 in the first stage and tested them for association in the second stage. The meta-analysis combining the first and second stages identified an SNP, rs577948, at chromosome 11q24.1, which was associated with the disease (P = 2.22×10−7 and OR of 1.37 with 95% confidence interval: 1.21–1.54). Two genes, BLID and LOC399959, were identified within a 200-kb DNA encompassing rs577948. RT–PCR analysis demonstrated that both genes were expressed in human retinal tissue. Our results strongly suggest that the region at 11q24.1 is a novel susceptibility locus for pathological myopia in Japanese
Development of a multi-pixel photon sensor with single-photon sensitivity
A multi-pixel photon sensor with single-photon sensitivity has been
developed, based on a technology of a hybrid photo-detector (HPD) consisting of
a photocathode and a multi-pixel avalanche diode (MP-AD). The developed HPD has
a proximity focused structure, where a photocathode and an MP-AD are facing
each other with a small gap of 2.5 mm. The MP-AD, which has an effective area
of 16x16 mm2 composed of 8x8 pixels, has been specially designed for the HPD.
The gain of the HPD reaches 5x10^4, sufficiently high to detect single photons
with a timing resolution better than 100 ps. Number of photoelectrons up to
four can be clearly identified in a pulse-height spectrum as distinct peaks,
thanks to the low noise characteristics of the HPD. It is also demonstrated
that the HPD can be operated with good performance in a magnetic field as high
as 1.5 TComment: 39 pages, 22 figures, submitted to Nucl. Intr. and Meth.
Surface Aligned Magnetic Moments and Hysteresis of an Endohedral Single-Molecule Magnet on a Metal
The interaction between the endohedral unit in the single-molecule magnet
DyScN@C and a rhodium (111) substrate leads to alignment of the Dy
4 orbitals. The resulting orientation of the DyScN plane parallel to the
surface is inferred from comparison of the angular anisotropy of x-ray
absorption spectra and multiplet calculations in the corresponding ligand
field. The x-ray magnetic circular dichroism (XMCD) is also angle dependent and
signals strong magnetocrystalline anisotropy. This directly relates geometric
and magnetic structure. Element specific magnetization curves from different
coverages exhibit hysteresis at a sample temperature of K. From the
measured hysteresis curves we estimate the zero field remanence life-time
during x-ray exposure of a sub-monolayer to be about 30 seconds.Comment: 5 pages, 4 figure
Determination of the bonding configuration of the metastable molecular oxygen adsorbed on a Si(111)-(7×7) surface
Site- and spin-dependent coupling at the highly ordered h-BN/Co(0001) interface
Using photoelectron diffraction and spectroscopy, we explore the structural and electronic properties of the hexagonal boron nitride (h-BN) monolayer epitaxially grown on the Co(0001) surface. Perfect matching of the lattice parameters allows formation of a well-defined interface where the B atoms occupy the hollow sites while the N atoms are located above the Co atoms. The corrugation of the h-BN monolayer and its distance from the substrate were determined by means of R-factor analysis. The obtained results are in perfect agreement with the density functional theory (DFT) predictions. The electronic structure of the interface is characterized by a significant mixing of the h-BN and Co states. Such hybridized states appear in the h-BN band gap. This allows to obtain atomically resolved scanning tunneling microscopy (STM) images from the formally insulating 2D material being in contact with ferromagnetic metal. The STM images reveal mainly the nitrogen sublattice due to a dominating contribution of nitrogen orbitals to the electronic states at the Fermi level. We believe that the high quality, well-defined structure and interesting electronic properties make the h-BN/Co(0001) interface suitable for spintronic applications.L.V.Ya. acknowledges the RSF (Grant No. 16-42-01093). A.V.T., V.O.S., K.A.B., O.Yu.V., and D.Yu.U. acknowledge St. Petersburg State University for research Grant No. 11.65.42.2017. M.V.K. and I.I.O. acknowledge the RFBR (Grant No. 16-29-06410). C.L. acknowledges the DFG (Grant Nos. LA655-17/1 and LA655-19/1).Peer reviewe
Surface Aligned Magnetic Moments and Hysteresis of an Endohedral Single-Molecule Magnet on a Metal
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