1,039 research outputs found
Important Roles of Te 5p and Ir 5d Spin-orbit Interactions on the Multi-band Electronic Structure of Triangular Lattice Superconductor Ir1-xPtxTe2
We report an angle-resolved photoemission spectroscopy (ARPES) study on a
triangular lattice superconductor IrPtTe in which the Ir-Ir
or Te-Te bond formation, the band Jahn-Teller effect, and the spin-orbit
interaction are cooperating and competing with one another. The Fermi surfaces
of the substituted system are qualitatively similar to the band structure
calculations for the undistorted IrTe with an upward chemical potential
shift due to electron doping. A combination of the ARPES and the band structure
calculations indicates that the Te spin-orbit interaction removes the
orbital degeneracy and induces type spin-orbit
coupling near the A point. The inner and outer Fermi surfaces are entangled by
the Te and Ir spin-orbit interactions which may provide exotic
superconductivity with singlet-triplet mixing.Comment: 10 pages, 4 figure
Electronic structure reconstruction by orbital symmetry breaking in IrTe2
We report an angle-resolved photoemission spectroscopy (ARPES) study on IrTe2
which exhibits an interesting lattice distortion below 270 K and becomes
triangular lattice superconductors by suppressing the distortion via chemical
substitution or intercalation. ARPES results at 300 K show multi-band Fermi
surfaces with six-fold symmetry which are basically consistent with band
structure calculations. At 20 K in the distorted phase, whereas the flower
shape of the outermost Fermi surface does not change from that at 300 K,
topology of the inner Fermi surfaces is strongly modified by the lattice
distortion. The Fermi surface reconstruction by the distortion depends on the
orbital character of the Fermi surfaces, suggesting importance of Ir 5d and/or
Te 5p orbital symmetry breaking.Comment: 4pages, 4figure
Spectromicroscopy of electronic phase separation in KFeSe superconductor
Structural phase separation in AFeSe system has been studied
by different experimental techniques, however, it should be important to know
how the electronic uniformity is influenced, on which length scale the
electronic phases coexist, and what is their spatial distribution. Here, we
have used novel scanning photoelectron microscopy (SPEM) to study the
electronic phase separation in KFeSe, providing a direct
measurement of the topological spatial distribution of the different electronic
phases. The SPEM results reveal a peculiar interconnected conducting
filamentary phase that is embedded in the insulating texture. The filamentary
structure with a particular topological geometry could be important for the
high T superconductivity in the presence of a phase with a large magnetic
moment in AFeSe materials.Comment: 14 pages,3 figure
NUMERICAL EXPERIMENT ON EFFECT OF SURFACE ROUGHNESS FOR HEAT AND FLOW AROUND TWO CONTACTING PARTICLES
The aim of the present work is to establish a model of heat transfer between particles by using the numerical simulation that can be incorporated in the discrete element method (DEM). The contact heat transfer between particles can be regarded as a contact thermal resistance problem. In the thermal resistance model, the local characteristics, e.g. exact contact area and heat flux distribution on particle surface, are important. However, it is difficult to measure such factors in detail. Accordingly, the authors utilized a numerical simulation. The thermal resistance was modeled by placing a small solid block between the contacting areas in the simulation. The small solid thickness represents the surface roughness and the width represents the contact force. The simulated temperature profile along the center line through two particle’s centers well agreed with measured one
Die Wirkung des Lichtes auf das trocknende Öl (I)
(1) Es wird der Grundversuch für die Wirkung des Lichtes auf das trocknende Öl beschrieben. (2) Das Leinöl wurde unter Einblasung des Sauerstoffes mit einer konstant brennenden Quecksilberbogenlampe belichtet. Die Belichtung wurde bei 5 °C durchgeführt, um die Wärmereaktion zu verlangsamen. Der Umwandelungsverlauf des Öles liess sich durch Veränderung der Jodzahl ermessen. (3) Im grossen und ganzen verändern sich nur unbedeutend einige Konstanten, d.h. spezifisches Gewicht, Viskosität, Lichtbrechungsvermögen, Säurezahl, Jodzahl u.s.w. sowohl durch 3-stündige als auch 6-stündige Belichtung. (4) Bemerkenswerter ist hierbei das Verhalten des vorbelichteten Öles gegen Erwärmung. Dies oxydiert durch Erwärmung endgültig rascher als das unvorbelichtete Öl. (5) Das Versnchsergebnis spricht dafür, dass der Zwischenstoff bzw. Beschleuniger, dessen Anwesenheit die Verwandelung leichter vor sich gehen lässt, hauptsächlich durch Belichtung gebildet wird. (6) Die Verwandelungsgeschwindigkeit, welche zu Anfang sehr klein ist, vergrössert sich beschleunigend bis zum Maximum, um sich dann ein wenig zu vermindern. Hierbei tritt das Maximum um so früher ein, je länger das Öl vorbelichtet war. (7) Das Ergebnis (6) wird vermöge der kinetischen Darstellung aufgeklärt
Embryonic Regulation of the Mouse Hematopoietic Niche
Hematopoietic stem cells (HSCs) can differentiate into several types of hematopoietic cells (HCs) (such as erythrocytes, megakaryocytes, lymphocytes, neutrophils, or macrophages) and also undergo self-renewal to sustain hematopoiesis throughout an organism's lifetime. HSCs are currently used clinically as transplantation therapy in regenerative medicine and are typically obtained from healthy donors or cord blood. However, problems remain in HSC transplantation, such as shortage of cells, donor risks, rejection, and graft-versus-host disease (GVHD). Thus, increased understanding of HSC regulation should enable us to improve HSC therapy and develop novel regenerative medicine techniques. HSC regulation is governed by two types of activity: intrinsic regulation, programmed primarily by cell autonomous gene expression, and extrinsic factors, which originate from so-called “niche cells” surrounding HSCs. Here, we focus on the latter and discuss HSC regulation with special emphasis on the role played by niche cells
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