277 research outputs found
Bifurcation analysis in an associative memory model
We previously reported the chaos induced by the frustration of interaction in
a non-monotonic sequential associative memory model, and showed the chaotic
behaviors at absolute zero. We have now analyzed bifurcation in a stochastic
system, namely a finite-temperature model of the non-monotonic sequential
associative memory model. We derived order-parameter equations from the
stochastic microscopic equations. Two-parameter bifurcation diagrams obtained
from those equations show the coexistence of attractors, which do not appear at
absolute zero, and the disappearance of chaos due to the temperature effect.Comment: 19 page
Cluster rearrangement by chiral charge order in lacunar spinel GaNbSe
Transition-metal atoms with d electrons sometimes form clusters in crystals,
which significantly affects the physical properties. Such a cluster formation
frequently accompanies a change in the crystal system, leading to the presence
of domains with different crystal orientations. In particular, the cubic
symmetry is rarely retained after the cluster formation. Here, we identify a
cubic-to-cubic phase transition in lacunar spinel GaNbSe, where the
change in the lattice parameter is less than 0.0001%. Each Nb
tetramer with seven 4d electrons is distorted into a Nb trimer and a
Nb monomer induced by charge disproportionation among Nb ions. While the
Nb trimer with six 4d electrons forms spin-singlets in the sigma-bonding
orbitals for three Nb-Nb bonds, a localized S=1/2 spin remains on the Nb
ion. Furthermore, a local electric dipole moment is induced along the
three-fold rotation axis of each distorted tetramer by the cluster
rearrangement. The electric dipole moments are regularly arranged to maintain
the cubic symmetry, giving rise to chiral order.Comment: 24 pages, 4 figures, supporting informatio
The snowfall-cloud at Syowa Station identified by convolutional neural network
The Tenth Symposium on Polar Science/Ordinary sessions: [OM] Polar Meteorology and Glaciology, Wed. 4 Dec. / 2F Auditorium, National Institute of Polar Researc
Real-Space Observation of Ligand Hole State in Cubic Perovskite SrFeO
An anomalously high valence state sometimes shows up in transition-metal
oxide compounds. In such systems, holes tend to occupy mainly the ligand
orbitals, giving rise to interesting physical properties such as
superconductivity in cuprates and rich magnetic phases in ferrates. However, no
one has ever observed the distribution of ligand holes in real space. Here, we
report a successful observation of the spatial distribution of valence
electrons in cubic perovskite SrFeO by high-energy X-ray diffraction
experiments and precise electron density analysis using a core differential
Fourier synthesis method. A real-space picture of ligand holes formed by the
orbital hybridization of Fe 3 and O 2 is revealed. The anomalous valence
state in Fe is attributed to the considerable contribution of the ligand hole,
which is related to the metallic nature and the absence of Jahn-Teller
distortions in this system.Comment: 14 pages, 4 figure
Edge and bulk states in Weyl-orbit quantum Hall effect as studied by Corbino measurements
We investigate edge and bulk states in Weyl-orbit based quantum Hall effect
by measuring a Corbino-type device fabricated from a topological Dirac
semimetal (Cd1-xZnx)3As2 film. Clear quantum Hall plateaus are observed when
measuring one-sided terminals of the Corbino-type device. This indicates that
edge states of the Weyl-orbit quantum Hall effect form closed trajectories
consisting of Fermi arcs and chiral zero modes independently on inner and outer
sides. On the other hand, the bulk resistance does not diverge at fields where
the quantum Hall plateau appears, suggesting that the Weyl orbits in the bulk
region are not completely localized when applying electric current through the
bulk region
PHOSPHORUS RECOVERY FROM SEWAGE-SLUDGE MOLTEN SLAG USING A COMBINATION OF ACID-DISSOLUTION, ALKALI-PRECIPITATION, AND ION-EXCHANGE
We recently reported an efficient procedure for recovering phosphoric acid from dephosphorization slag. This recovery procedure consists of a combination of the following four processes: (1) A first dissolution process of slag in a nitric acid solution; (2) a precipitation process then adds ammonia to the obtained eluate; (3) a second dissolution process dissolves the precipitation from the nitric acid eluate; and, (4) the final process involves ion exchange in which the obtained eluate is passed through an ion exchange resin. In the present study, this recovery procedure was applied to concentrate and recover phosphorus from sewage-sludge molten slag, which is an unused resource that should be considered a new resource for phosphorus. As a result, our procedure for recovery from dephosphorization slag was viable following two revisions. Initially, the time for the first dissolution process was extended from 0.2 h to 1 h, but 0.2 h proved to be the optimum time for dephosphorization slag. Next, we discovered it was better to perform the filtration one day after adding the ammonia instead of immediately after adding it. The other two processes could be treated under substantially the same conditions as in the case of dephosphorization slag, and high-purity phosphorus was obtained
SOCS1 Is a Suppressor of Liver Fibrosis and Hepatitis-induced Carcinogenesis
Hepatocellular carcinomas (HCCs) mainly develop from liver cirrhosis and severe liver fibrosis that are established with long-lasting inflammation of the liver. Silencing of the suppressor of the cytokine signaling-1 (SOCS1) gene, a negative regulator of cytokine signaling, by DNA methylation has been implicated in development or progress of HCC. However, how SOCS1 contributes to HCC is unknown. We examined SOCS1 gene methylation in >200 patients with chronic liver disease and found that the severity of liver fibrosis is strongly correlated with SOCS1 gene methylation. In murine liver fibrosis models using dimethylnitrosamine, mice with haploinsufficiency of the SOCS1 gene (SOCS1β/+ mice) developed more severe liver fibrosis than did wild-type littermates (SOCS1+/+ mice). Moreover, carcinogen-induced HCC development was also enhanced by heterozygous deletion of the SOCS1 gene. These findings suggest that SOCS1 contributes to protection against hepatic injury and fibrosis, and may also protect against hepatocarcinogenesis
Scalar order: possible candidate for order parameters in skutterudites
Phenomenological Landau analysis shows that the properties of ordered phases
in some skutterudites are consistently accounted for by a scalar order
parameter which preserves the cubic symmetry, even in the ordered phase. A
universal value is found for the anisotropy ratio of the transition temperature
in a magnetic field, homogeneous magnetization, and induced staggered
magnetization. The difference in magnetic behavior between PrFeP and
PrRuP near their phase transitions is explained within a single
framework. For the low-field phase of PrFeP, the scalar order with
the symmetry can explain (i) the absence of field induced dipoles
perpendicular to the magnetic field, (ii) isotropic magnetic susceptibility in
the ordered phase, (iii) the field angle dependence of the transition
temperature, and (iv) the splitting pattern of the P nuclear magnetic
resonance (NMR) spectra. It is proposed how the order parameter in
SmRuP is identified by NMR analysis of a single crystal.Comment: 4 pages, 4 figure
- β¦