895 research outputs found
The read-out system of spatial distribution of thermoluminescence in meteorites
The thermoluminescence (TL) technique used for dating the terrestrial age of meteorites is based on the TL fading of interior samples. The depth dependence of the TL for Antarctic meteorites with fusion crust is measured. Usually, meteorites are powdered and their TL measured under a photomultiplier. In this case, a TL spatial distribution of a cross section of antarctic meteorites is measured using a read out system of spatial distribution of TL, since a meteorite is made up of inhomogeneous material. Antarctic meteorites MET-78028(L6) and ALH-77278(L13) are used
Effects of annealing time on structural and magnetic properties of L10-FePt nanoparticles synthesized by the SiO2-nanoreactor method
We investigated effects of annealing time on structural and magnetic
properties of the L10-FePt nanoparticles synthesized by the SiO2-nanoreacter
method. The magnetization and powder X-ray diffraction studies revealed that
the annealing at 900 oC for 9 hr could convert all of the fcc-nanoparticles to
the well-crystallized L10 structure with a large coercivity while keeping their
particle size. Such monodisperse and highly crystalline L10-FePt nanoparticles
are a promising material for the realization of ultra-high density recording.Comment: 9 pages, 2 figure
Differential distribution of microtubules in immature osteocytes in vivo
Objectives: The transition from osteoblasts to osteocytes is associated with dramatic changes in the cytoskeleton. We previously showed that the formation of osteoblast cell processes in 3D culture is microtubule dependent. However, the distribution of microtubules during the transition from osteoblasts to osteocytes in vivo is unknown. In this study, we investigated the distribution of microtubules in osteocytes in vivo. Methods: We observed the microtubules in osteocytes in chick embryonic calvaria via fluorescence staining of microtubules and confocal laser scanning microscopy. Results: Microtubules were observed throughout the cytoplasm in all examined osteoblasts. In immature osteocytes, several cell processes contained microtubules, whereas in mature osteocytes, microtubules were localized only in the cell body. Conclusion: These results suggest that the early arrangement of microtubules may be correlated with the initial development of osteocyte processes. (C) 2018 Japanese Association for Oral Biology. Published by Elsevier B.V. All rights reserved.Peer reviewe
Experimental exploration of ErB and SHAP analysis on a machine-learned model of magnetocaloric materials for materials design
Stimulated by a recent report of a giant magnetocaloric effect in HoB
found via machine-learning predictions, we have explored the magnetocaloric
properties of a related compound ErB, that has remained the last
ferromagnetic material among the rare-earth diboride (REB) family with
unreported magnetic entropy change |{\Delta}SM|. The evaluated
at field change of 5 T in ErB turned out to be as high as 26.1 (J kg
K) around the ferromagnetic transition () of 14 K. In this
series, HoB is found to be the material with the largest as
the model predicted, while the predicted values showed a deviation with a
systematic error compared to the experimental values. Through a coalition
analysis using SHAP, we explore how this rare-earth dependence and the
deviation in the prediction are deduced in the model. We further discuss how
SHAP analysis can be useful in clarifying favorable combinations of constituent
atoms through the machine-learned model with compositional descriptors. This
analysis helps us to perform materials design with aid of machine learning of
materials data.Comment: 9 pages, 10 figures. Accepted manuscript. Published by Taylor &
Francis in STAM:Methods, available at
https://doi.org/10.1080/27660400.2023.221747
Growth Dynamics of Photoinduced Domains in Two-Dimensional Charge-Ordered Conductors Depending on Stabilization Mechanisms
Photoinduced melting of horizontal-stripe charge orders in
quasi-two-dimensional organic conductors
\theta-(BEDT-TTF)2RbZn(SCN)4[BEDT-TTF=bis(ethylenedithio)tetrathiafulvalene]
and
\alpha-(BEDT-TTF)2I3 is investigated theoretically. By numerically solving
the time-dependent Schr\"odinger equation, we study the photoinduced dynamics
in extended Peierls-Hubbard models on anisotropic triangular lattices within
the
Hartree-Fock approximation. The melting of the charge order needs more energy
for \theta-(BEDT-TTF)2RbZn(SCN)4 than for \alpha-(BEDT-TTF)2I3, which is a
consequence of the larger stabilization energy in \theta-(BEDT-TTF)2RbZn(SCN)4.
After local photoexcitation in the charge ordered states, the growth of a
photoinduced domain shows anisotropy. In \theta-(BEDT-TTF)2RbZn(SCN)4, the
domain hardly expands to the direction perpendicular to the horizontal-stripes.
This is because all the molecules on the hole-rich stripe are rotated in one
direction and those on the hole-poor stripe in the other direction. They
modulate horizontally connected transfer integrals homogeneously, stabilizing
the charge order stripe by stripe. In \alpha-(BEDT-TTF)2I3, lattice distortions
locally stabilize the charge order so that it is easily weakened by local
photoexcitation. The photoinduced domain indeed expands in the plane. These
results are consistent with recent observation by femtosecond reflection
spectroscopy.Comment: 9 pages, 8 figures, to appear in J. Phys. Soc. Jpn. Vol. 79 (2010)
No.
Neural networks for a quick access to a digital twin of scanning physical properties measurements
For performing successful measurements within limited experimental time,
efficient use of preliminary data plays a crucial role. This work shows that a
simple feedforward type neural networks approach for learning preliminary
experimental data can provide quick access to simulate the experiment within
the learned range. The approach is especially beneficial for physical
properties measurements with scanning on multiple axes, where derivative or
integration of data are required to obtain the objective quantity. Due to its
simplicity, the learning process is fast enough for the users to perform
learning and simulation on-the-fly by using a combination of open-source
optimization techniques and deep-learning libraries. Here such a tool for
augmenting the experimental data is proposed, aiming to help researchers to
decide the most suitable experimental conditions before performing costly
experiments in real. Furthermore, this tool can also be used from the
perspective of taking advantage of reutilizing and repurposing previously
published data, accelerating data-driven exploration of functional materials.Comment: 19 pages, 5 figures + 7 pages of Supporting Informatio
Charge Order with Structural Distortion in Organic Conductors: Comparison between \theta-(ET)2RbZn(SCN)4 and \alpha-(ET)2I3
Charge ordering with structural distortion in quasi-two-dimensional organic
conductors \theta-(ET)2RbZn(SCN)4 (ET=BEDT-TTF) and \alpha-(ET)2I3 is
investigated theoretically. By using the Hartree-Fock approximation for an
extended Hubbard model which includes both on-site and intersite Coulomb
interactions together with Peierls-type electron-lattice couplings, we examine
the role of lattice degrees of freedom on charge order. It is found that the
experimentally observed, horizontal charge order is stabilized by lattice
distortion in both compounds. In particular, the lattice effect is crucial to
the realization of the charge order in \theta-(ET)2RbZn(SCN)4, while the
peculiar band structure whose symmetry is lower than that of
\theta-(ET)2RbZn(SCN)4 in the metallic phase is also an important factor in
\alpha-(ET)2I3 together with the lattice distortion. For \alpha-(ET)2I3, we
obtain a phase transition from a charge-disproportionated metallic phase to the
horizontal charge order with lattice modulations, which is consistent with the
latest X-ray experimental result.Comment: 10 pages, 13 figures, to appear in J. Phys. Soc. Jpn. Vol. 77 (2008)
No.
Combination of Ferromagnetic and Antiferromagnetic Features in Heisenberg Ferrimagnets
We investigate the thermodynamic properties of Heisenberg ferrimagnetic
mixed-spin chains both numerically and analytically with particular emphasis on
the combination of ferromagnetic and antiferromagnetic features. Employing a
new density-matrix renormalization-group technique as well as a quantum Monte
Carlo method, we reveal the overall thermal behavior: At very low temperatures,
the specific heat and the magnetic susceptibility times temperature behave like
and , respectively, whereas at intermediate temperatures,
they exhibit a Schottky-like peak and a minimum, respectively. Developing the
modified spin-wave theory, we complement the numerical findings and give a
precise estimate of the low-temperature behavior.Comment: 9 pages, 9 postscript figures, RevTe
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