1,867 research outputs found
Multiphase transport model for heavy ion collisions at RHIC
Using a multiphase transport model (AMPT) with both partonic and hadronic
interactions, we study the multiplicity and transverse momentum distributions
of charged particles such as pions, kaons and protons in central Au+Au
collisions at RHIC energies. Effects due to nuclear shadowing and jet quenching
on these observables are also studied. We further show preliminary results on
the production of multistrange baryons from the strangeness-exchange reactions
during the hadronic stage of heavy ion collisions.Comment: 4 pages, 4 figures, espcrc1.sty included, presented at 15th
International Conference on Ultra-Relativistic Nucleus-Nucleus Collisions
(QM2001), Long Island, New York, January 200
Enhanced transmission of optically thick metallic films at infrared wavelengths
For an optically thick metallic film, the transmission for both s- and
p-polarized waves is extremely low. If the metallic film is coated on both
sides with a finite dielectric layer, light transmission for -polarized
waves can be enhanced considerably. This enhancement is not related to surface
plasmon-polaritions. Instead, it is due to the interplay between Fabry-Perot
interference in the coated dielectric layer and the existence of the Brewster
angle at the dielectric/metallic interface. It is shown that the coated
metallic films can act as excellent polarizers at infrared wavelengths.Comment: 3 pages, 4 figures. Submitted to Appl. Phys. Let
Loschmidt Echo and Berry phase of the quantum system coupled to the XY spin chain: Proximity to quantum phase transition
We study the Loschmidt echo (LE) of a coupled system consisting of a central
spin and its surrounding environment described by a general XY spin-chain
model. The quantum dynamics of the LE is shown to be remarkably influenced by
the quantum criticality of the spin chain. In particular, the decaying behavior
of the LE is found to be controlled by the anisotropy parameter of the spin
chain. Furthermore, we show that due to the coupling to the spin chain, the
ground-state Berry phase for the central spin becomes nonanalytical and its
derivative with respect to the magnetic parameter in spin chain
diverges along the critical line , which suggests an alternative
measurement of the quantum criticality of the spin chain.Comment: 15 pages, 5 figure
Determining the Dust Extinction of Gamma-ray Burst Host Galaxies: A Direct Method Based on Optical and X-ray Photometry
Origin of Native Driving Force in Protein Folding
We derive an expression with four adjustable parameters that reproduces well
the 20x20 Miyazawa-Jernigan potential matrix extracted from known protein
structures. The numerical values of the parameters can be approximately
computed from the surface tension of water, water-screened dipole interactions
between residues and water and among residues, and average exposures of
residues in folded proteins.Comment: LaTeX file, Postscript file; 4 pages, 1 figure (mij.eps), 2 table
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Suitability of binary oxides for molecular-beam epitaxy source materials: A comprehensive thermodynamic analysis
We have conducted a comprehensive thermodynamic analysis of the volatility of 128 binary oxides to evaluate their suitability as source materials for oxide molecular-beam epitaxy (MBE). 16 solid or liquid oxides are identified that evaporate nearly congruently from stable oxide sources to gas species: As2O3, B2O3, BaO, MoO3, OsO4, P2O5, PbO, PuO2, Rb2O, Re2O7, Sb2O3, SeO2, SnO, ThO2, Tl2O, and WO3. An additional 24 oxides could provide molecular beams with dominant gas species of CeO, Cs2O, DyO, ErO, Ga2O, GdO, GeO, HfO, HoO, In2O, LaO, LuO, NdO, PmO, PrO, PuO, ScO, SiO, SmO, TbO, Te2O2, U2O6, VO2, and YO2. The present findings are in close accord with available experimental results in the literature. For example, As2O3, B2O3, BaO, MoO3, PbO, Sb2O3, and WO3 are the only oxides in the ideal category that have been used in MBE. The remaining oxides deemed ideal for MBE awaiting experimental verification. We also consider two-phase mixtures as a route to achieve the desired congruent evaporation characteristic of an ideal MBE source. These include (Ga2O3 + Ga) to produce a molecular beam of Ga2O(g), (GeO2 + Ge) to produce GeO(g), (SiO2 + Si) to produce SiO(g), (SnO2 + Sn) to produce SnO(g), etc.; these suboxide sources enable suboxide MBE. Our analysis provides the vapor pressures of the gas species over the condensed phases of 128 binary oxides, which may be either solid or liquid depending on the melting temperature. © 2020 Author(s)
Understanding the chemical evolution of blue Edge-on Low Surface Brightness Galaxies
We present a sample of 330 blue edge-on low surface brightness galaxies
(ELSBGs). To understand the chemical evolution of LSBGs, we derived the
gas-phase abundance and the [/Fe] ratio. Compared with star-forming
galaxies, ELSBGs show a flatter trend in the mass-metallicity ()
relation, suggesting that the oxygen abundance enhancement is inefficient. We
focus on 77 ELSBGs with HI data and found the closed-box model can not explain
their gas fraction and metallicity relation, implying that infall and/or
outflow is needed. We derived the [/Fe] ratio of normal ELSBG (
10M) and massive ELSBG ( 10M) using single
stellar population grids from MILES stellar library. The mean [/Fe]
ratios are 0.18 and 0.4 for normal ELSBG and massive ELSBG, respectively. We
discussed that the long time-scale of star-formation, and/or metal-rich gas
outflow event caused by SNe Ia winds are likely responsible for the
-enhancement of massive ELSBGs.Comment: 9 pages, 9 figures, Accepted for publication in Ap
Wigner function evolution in self-Kerr Medium derived by Entangled state representation
By introducing the thermo entangled state representation, we convert the
calculation of Wigner function (WF) of density operator to an overlap between
"two pure" states in a two-mode enlarged Fock space. Furthermore, we derive a
new WF evolution formula of any initial state in self-Kerr Medium with photon
loss and find that the photon number distribution for any initial state is
independent of the coupling factor with Kerr Medium, where the number state is
not affected by the Kerr nonlinearity and evolves into a density operator of
binomial distribution.Comment: 9 pages, 1 figur
Enhanced biomedical heat-triggered carriers via nanomagnetism tuning in ferrite-based nanoparticles
Biomedical nanomagnetic carriers are getting a higher impact in therapy and
diagnosis schemes while their constraints and prerequisites are more and more
successfully confronted. Such particles should possess a well-defined size
with minimum agglomeration and they should be synthesized in a facile and
reproducible high-yield way together with a controllable response to an
applied static or dynamic field tailored for the specific application. Here,
we attempt to enhance the heating efficiency in magnetic particle hyperthermia
treatment through the proper adjustment of the core–shell morphology in
ferrite particles, by controlling exchange and dipolar magnetic interactions
at the nanoscale. Thus, core–shell nanoparticles with mutual coupling of
magnetically hard (CoFe2O4) and soft (MnFe2O4) components are synthesized with
facile synthetic controls resulting in uniform size and shell thickness as
evidenced by high resolution transmission electron microscopy imaging,
excellent crystallinity and size monodispersity. Such a magnetic coupling
enables the fine tuning of magnetic anisotropy and magnetic interactions
without sparing the good structural, chemical and colloidal stability.
Consequently, the magnetic heating efficiency of CoFe2O4 and MnFe2O4
core–shell nanoparticles is distinctively different from that of their
counterparts, even though all these nanocrystals were synthesized under
similar conditions. For better understanding of the AC magnetic hyperthermia
response and its correlation with magnetic-origin features we study the effect
of the volume ratio of magnetic hard and soft phases in the bimagnetic
core−shell nanocrystals. Eventually, such particles may be considered as novel
heating carriers that under further biomedical functionalization may become
adaptable multifunctional heat-triggered nanoplatforms
Functional characterization of D9, a novel deazaneplanocin a (DZNep) analog, in targeting acute myeloid leukemia (AML)
10.1371/journal.pone.0122983PLoS ONE104e012298
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