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Angle-resolved photoemission spectroscopy using a micro-focused beam spot (micro-ARPES) is becoming a powerful tool to elucidate key electronic states of exotic quantum materials. We have developed a versatile micro-ARPES system based on synchrotron radiation beam focused with a Kirkpatrick-Baez mirror optics. The mirrors are monolithically installed on a stage, which is driven with five-axes motion, and are vibrationally separated from the ARPES measurement system. Spatial mapping of the Auphotolithography pattern on Si signifies the beam spot size of 10 $\mu$m (horizontal) x 12 $\mu$m (vertical) at the sample position, which is well suited to resolve the fine structure in local electronic states. Utilization of the micro beam and the high precision sample motion system enables the accurate spatially resolved band-structure mapping, as demonstrated by the observation of a small band anomaly associated with tiny sample bending near the edge of a cleaved topological insulator single crystal., Comment: 21 pages, 8 figures

An azimuthal-rotation sample holder, with improvements in the rotation-angle accuracy and rotation-axes displacement during azimuthal rotation, was developed for molecular-orientation analysis using scanning transmission X-ray microscopy., In this study, an azimuthal-rotation sample holder compatible with scanning transmission X-ray microscopy was developed. This holder exhibits improvement in the accuracy of rotation angles and reduces the displacement of the rotation axes during azimuthal rotation by using a crossed roller bearing. To evaluate the performance of the holder, the authors investigated the dependence of the optical density around the C K-edge absorption of π-orbital-oriented domains in natural spherical graphite on the rotational angle by using linearly horizontally and vertically polarized undulator radiation. Based on the dependence of the optical density ratio between C 1s → π* and 1s → σ* excitation on the polarization angle of the X-rays, the average two-dimensional orientation angle of the π orbital in each position in a natural spherical graphite sample was visualized.

Beamline 13 of the Photon Factory has been in operation since 2010 as a vacuum ultraviolet and soft X-ray undulator beamline for X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), and angle-resolved photoelectron spectroscopy (ARPES) experiments. The beamline and the end-station at branch B have been recently upgraded, enabling microscopic XPS, XAS, and ARPES measurements to be performed. In 2015, a planar undulator insertion device was replaced with an APPLE-II (advanced planar polarized light emitter II) undulator. This replacement allows use of linear, circular, and elliptical polarized light between 48 and 2000 eV with photon intensities of 109–1013 photons s−1. For microscopic measurements, a toroidal post-mirror was renewed to have more focused beam with profile sizes of 78 µm (horizontal) × 15 µm (vertical) and 84 µm × 11 µm at photon energies of 100 and 400 eV, respectively. A high-precision sample manipulator composed of an XYZ translator, a rotary feedthrough, and a newly developed goniometer, which is essential for microscopic measurements, has been used to control a sample specimen in six degrees of freedom, i.e. translation in the X, Y, and Z directions and rotation in the polar, azimuthal, and tilt directions. To demonstrate the performance of the focused beams, one- and two-dimensional XPS and XAS scan measurements of a copper grid have been performed. It was indicated from analysis of XPS and XAS intensity maps that the actual spatial resolution can be determined by the beam size.

The 11th Symposium on Polar Science/Ordinary sessions: [OA] Antarctic meteorites, Thu. 3 Dec.

At a soft X-ray beamline with an undulator source, significant heat generation at the first-mirror chamber and light emission at the viewport were found, which can be explained by photoelectrons from the mirror. The chamber temperature increases up to approximately 50°C over a period of several hours. A photoelectron shield consisting of thin copper plates not only prevents the heat generation and light emission but also improves the pressure of the vacuum chamber, if a voltage of a few tens of V is applied to the shield. The total electron yield of the shield reached as much as 58 mA under high heat-load conditions, indicating the emission of numerous photoelectrons from the first mirror. Heat-balance analyses suggest that approximately 30% or more of the heat load on the first mirror is transferred to the surroundings.

The structure of hydrous amorphous SiO2 is fundamental in order to investigate the effects of water on the physicochemical properties of oxide glasses and magma. The hydrous SiO2 glass with 13 wt.% D2O was synthesized under high-pressure and high-temperature conditions and its structure was investigated by small angle X-ray scattering, X-ray diffraction, and neutron diffraction experiments at pressures of up to 10 GPa and room temperature. This hydrous glass is separated into two phases: a major phase rich in SiO2 and a minor phase rich in D2O molecules distributed as small domains with dimensions of less than 100 &Aring, Medium-range order of the hydrous glass shrinks compared to the anhydrous SiO2 glass by disruption of SiO4 linkage due to the formation of Si&ndash, OD deuterioxyl, while the response of its structure to pressure is almost the same as that of the anhydrous SiO2 glass. Most of D2O molecules are in the small domains and hardly penetrate into the void space in the ring consisting of SiO4 tetrahedra.

In electrical equipment, such as transformers and motors, rotating magnetic fluxes occur at T-joint parts and back yoke parts. It is therefore necessary to understand the magnetic properties and magnetostrictions under several rotating flux conditions. This paper presents measured vector magnetic properties including 2-D magnetostriction of a nonoriented electrical steel sheet (including a 6.5%SiFe sheet), a grain-oriented electrical steel sheet, and a permendur sheet under rotating flux conditions. The relationship among the magnetic flux density vector, the magnetic field strength vector, and the 2-D magnetostriction is clarified in comparison of the various electrical steel sheets. Furthermore, from the measurement results, suitable materials are suggested for equipment.

[1] The density data of silicate melts reported by static and shock compression have been compared quantitatively at the pressure condition of the Earth's deep upper mantle. The equation of state based on the static compression data cannot explain the shock compression data, and the systematic differences between them have been revealed. The shock temperatures were estimated with different methods among papers, and the reported values differed considerably from one another. The shock temperatures estimated by assuming phase-transition-like structural changes in melts lie between the previous estimates. Many of them are well below the liquidus temperatures of each sample, suggesting that the sample state may have been altered during the shock compression. In addition, some of the shock compression data reanalyzed in the recent paper differ considerably from the original. These results suggest that silicate melts show phase-transition-like structural changes at high pressures, which are consistent with the static compression data.

The K computer, released on September 29, 2012, is a large-scale parallel supercomputer system consisting of 82,944 compute nodes. We have been able to resolve a significant number of operation issues since its release. Some system software components have been fixed and improved to obtain higher stability and utilization. We achieved 94% service availability because of a low hardware failure rate and approximately 80% node utilization by careful adjustment of operation parameters. We found that the K computer is an extremely stable and high utilization system.

This paper deals with the magnetostriction of a grain-oriented electrical steel sheet measured by using the two-dimensional vector magnetic property measurement system and a three-axial strain gage. The magnetostrictions in arbitrary direction are calculated with the measured strain tensors. The magnetostriction characteristics were changed depending on the magnetization process according to the exciting magnetic flux density and the exciting direction. In this paper, we make clear the relationship among the two-dimensional magnetostriction, the magnetic flux density vector, and the magnetic field intensity vector in the grain- oriented electrical steel sheet. K e y w o r d s: vector magnetic property, three-dimensional magnetostriction, grain-oriented electrical steel sheet, magnetization process

This paper presents the measured magnetostriction of electrical steel sheets under alternating magnetic flux conditions. In the measurements, we used a two-dimensional vector magnetic property measurement system, and a three-axial strain gauge. In order to know the magnetostriction in an arbitrary direction, the strain tensor was evaluated. In addition, we try to evaluate the magnetostrictions in the thickness direction. In this paper, the three-dimensional magnetostriction in nonoriented and grain-oriented silicon steel sheets are compared. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 179(4): 1–9, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21257

To understand the stability of the liquid phase of ionic liquids under high pressure, we investigated the phase behavior of a series of 1-alkyl-3-methylimidazolium tetrafluoroborate ([Cnmim][BF4]) homologues with different alkyl chain lengths for 2 ≤ n ≤ 8 up to ∼7 GPa at room temperature. The ionic liquids exhibited complicated phase behavior, which was likely due to the conformational flexibility in the alkyl chain. The present results reveal that [Cnmim][BF4] falls into superpressed state around 2-3 GPa range upon compression with an implication of multiple phase or structural transitions to ∼7 GPa. Remarkably, a characteristic nanostructural organization in ionic liquids largely diminishes at the superpressed state. The behaviors of imidazolium-based ionic liquids can be classified into, at least, three patterns: (1) pressure-induced crystallization, (2) superpressurization upon compression, and (3) decompression-induced crystallization from the superpressurized glass. Interestingly, the high-pressure phase behavior was relevant to the glass transition behavior at low temperatures and ambient pressure. As n increases, the glass transition pressure (pg) decreases (from 2.8 GPa to ∼2 GPa), and the glass transition temperature increases. The results indicate that the p-T range of the liquid phase is regulated by the alkyl chain length of [Cnmim][BF4] homologues.