8,432 research outputs found
Editor Profile: Guest Editors of the Special Issue “Functional Materials, Nanocarriers, and Formulations for Targeted Therapy”
Value Discount of Business Groups Surrounding the Asia Financial Crisis: Evidence from Korean Chaebols
Asian Financial Crisis, Business Group, Chaebol, Diversification, Firm Value
StarGO: A New Method to Identify the Galactic Origins of Halo Stars
We develop a new method StarGO (Stars' Galactic Origin) to identify the
galactic origins of halo stars using their kinematics. Our method is based on
self-organizing map (SOM), which is one of the most popular unsupervised
learning algorithms. StarGO combines SOM with a novel adaptive group
identification algorithm with essentially no free parameters. In order to
evaluate our model, we build a synthetic stellar halo from mergers of nine
satellites in the Milky Way. We construct the mock catalogue by extracting a
heliocentric volume of 10 kpc from our simulations and assigning expected
observational uncertainties corresponding to bright stars from Gaia DR2 and
LAMOST DR5. We compare the results from StarGO against that from a
Friends-of-Friends (FoF) based method in the space of orbital energy and
angular momentum. We show that StarGO is able to systematically identify more
satellites and achieve higher number fraction of identified stars for most of
the satellites within the extracted volume. When applied to data from Gaia DR2,
StarGO will enable us to reveal the origins of the inner stellar halo in
unprecedented detail.Comment: 11 pages, 7 figures, Accepted for publication in Ap
Heating temperature prediction of concrete structure damaged by fire using a Bayesian approach
A fire that occurs in a reinforced concrete (RC) structure accompanies a heating temperature, and this negatively affects the concrete material properties, such as the compressive strength, the bond between cement paste and aggregate, and the cracking and spalling of concrete. To appropriately measure the reduced structural performance and durability of fire-damaged RC structures, it is important to accurately estimate the heating temperature of the structure. However, studies in the literature on RC structures damaged by fire have focused mostly on structural member tests at elevated temperatures to ensure the fire resistance or fire protection material development; studies on estimating the heating temperature are very limited except for the very few existing models. Therefore, in this study, a heating temperature estimation model for a reinforced concrete (RC) structure damaged by fire was developed using a statistical Bayesian parameter estimation approach. For the model development, a total of 77 concrete test specimens were utilized; based on them, a statistically highly accurate model has been developed. The usage of the proposed method in the framework of the 500 â—¦C isotherm method in Eurocode 2 has been illustrated through an RC column resistance estimation application
Competing spin-fluctuations in SrRuO and their tuning through epitaxial strain
In this study, we report the magnetic energy landscape of Sr2RuO4 employing
the generalized Bloch approach within density functional theory. We identify
the two dominant magnetic instabilities, ferromagnetic and spin-density-wave,
together with other predominant instabilities. We show that epitaxial strain
can change the overall magnetic tendency of the system, and tune the relative
weight of the various magnetic instabilities in the system. Especially, the
balance between spin-density wave and ferromagnetic instabilities can be
controlled by the strain, and, eventually can lead to the new magnetic phases
as well as superconducting phases with possibly altered pairing channels. Our
findings are compared with previous theoretical models and experimental reports
for the various magnetic features of the system and offer a first-principles
explanation to them
Tunable electronic and magnetic phases in layered ruthenates: SrRuO3-SrTiO3 heterostructure upon strain
Layered ruthenates are a unique class of systems which manifests a variety of
electronic and magnetic features emerged from competing energy scales. At the
heart of such features lies the multi-orbital physics, especially, the
orbital-selective behavior. Here, we propose that the SrRuO3-SrTiO3
heterostructure is a highly tunable platform to obtain the various emergent
properties. Employing the density functional theory plus dynamical mean-field
theory, we thoroughly investigate the orbital-dependent physics of the system
and identify the competing magnetic fluctuations. We show that the epitaxial
strain drives the system towards multi-orbital or orbital selective Mott phases
from the Hund metal regime. At the same time, the two different types of static
magnetism are stabilized, ferromagnetism and checkerboard antiferromagnetism,
from the competition with the spin-density wave instability.Comment: 5 pages, 3 figures in the main text, Supplemental Material is
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