15,922 research outputs found
Constrained structure of ancient Chinese poetry facilitates speech content grouping
Ancient Chinese poetry is constituted by structured language that deviates from ordinary language usage [1, 2]; its poetic genres impose unique combinatory constraints on linguistic elements [3]. How does the constrained poetic structure facilitate speech segmentation when common linguistic [4, 5, 6, 7, 8] and statistical cues [5, 9] are unreliable to listeners in poems? We generated artificial Jueju, which arguably has the most constrained structure in ancient Chinese poetry, and presented each poem twice as an isochronous sequence of syllables to native Mandarin speakers while conducting magnetoencephalography (MEG) recording. We found that listeners deployed their prior knowledge of Jueju to build the line structure and to establish the conceptual flow of Jueju. Unprecedentedly, we found a phase precession phenomenon indicating predictive processes of speech segmentation—the neural phase advanced faster after listeners acquired knowledge of incoming speech. The statistical co-occurrence of monosyllabic words in Jueju negatively correlated with speech segmentation, which provides an alternative perspective on how statistical cues facilitate speech segmentation. Our findings suggest that constrained poetic structures serve as a temporal map for listeners to group speech contents and to predict incoming speech signals. Listeners can parse speech streams by using not only grammatical and statistical cues but also their prior knowledge of the form of language
Superconducting correlations in ultra-small metallic grains
To describe the crossover from the bulk BCS superconductivity to a
fluctuation-dominated regime in ultrasmall metallic grains, new order
parameters and correlation functions, such as ``parity gap'' and ``pair-mixing
correlation function'', have been recently introduced. In this paper, we
discuss the small-grain behaviour of the Penrose-Onsager-Yang off-diagonal
long-range order (ODLRO) parameter in a pseudo-spin representation. Relations
between the ODLRO parameter and those mentioned above are established through
analytical and numerical calculations.Comment: 7 pages, 1 figur
An enhanced fluorescent ZIF-8 film by capturing guest molecules for light-emitting applications
Metal organic frameworks (MOFs) constructed from metal ions/clusters and organic linkers have led to new porous luminescent materials and, thus, have attracted much attention. But their photoluminescence quantum yields (PLQYs) are not high and the photoluminescence mechanism is still unclear. In order to solve this problem, in this work, zeolitic imidazolate framework-8 (ZIF-8, a kind of MOF) composite films containing small molecules of acetic acid were successfully prepared on a glass substrate via a sol–gel method, and they exhibited a high PLQY of 54.42%. Compared with pure ZIF-8 film, the obtained ZIF-8 composite film presented a significant enhancement in blue light emission. Moreover, the PLQY of the ZIF-8 composite film can be controlled to a certain extent via adjusting the molar ratio of the ligands to the zinc source. Among them, ZIF-8 film prepared at a molar ratio of 2.5 : 1 showed higher transmittance, and the fluorescence quantum efficiency reached 54.42%, which may be attributed to electron transfer between acetic acid as an electron-donor and the ZIF-8 structure caused by their relatively strong hydrogen bonding interactions. This work may provide new insights into the enhanced fluorescence of MOF materials for light-emitting applications
The ground state entanglement in the model
In this paper, we investigate spin entanglement in the model defined on
a -dimensional bipartite lattice. The concurrence, a measure of the
entanglement between two spins, is analyzed. We prove rigorously that the
ground state concurrence reaches maximum at the isotropic point. For
dimensionality , the concurrence develops a cusp at the isotropic
point and we attribute it to the existence of magnetic long-range order.Comment: 5 pages, 2 figure
Isospin effect in the statistical sequential decay
Isospin effect of the statistical emission fragments from the equilibrated
source is investigated in the frame of statistical binary decay implemented
into GEMINI code, isoscaling behavior is observed and the dependences of
isoscaling parameters and on emission fragment size, source
size, source isospin asymmetry and excitation energies are studied. Results
show that and neither depends on light fragment size nor on
source size. A good linear dependence of and on the inverse of
temperature is manifested and the relationship of
and
from different
isospin asymmetry sources are satisfied. The symmetry energy coefficient
extracted from simulation results is 23 MeV which includes
both the volume and surface term contributions, of which the surface effect
seems to play a significant role in the symmetry energy.Comment: 8 pages, 8 figures; A new substantially modified version which has
been accepted by the Physical Review
Phase transitions and iron-ordered moment form factor in LaFeAsO
Elastic neutron scattering studies of an optimized LaFeAsO single crystal
reveal that upon cooling, an onset of the tetragonal (T)-to-orthorhombic (O)
structural transition occurs at K, and it exhibits a
sharp transition at K. We argue that in the
temperature range to , T and O structures may
dynamically coexist possibly due to nematic spin correlations recently proposed
for the iron pnictides, and we attribute to the formation of
long-range O domains from the finite local precursors. The antiferromagnetic
structure emerges at K, with the iron moment
direction along the O \emph{a} axis. We extract the iron magnetic form factor
and use the tabulated of Fe, Fe and Fe to
obtain a magnetic moment size of 0.8 at 9.5 K.Comment: 7 pages, 6 figures, 3 table
Dynamical and sequential decay effects on isoscaling and density dependence of the symmetry energy
The isoscaling properties of the primary and final products are studied via
isospin dependent quantum molecular dynamics
(IQMD) model and the followed sequential decay model GEMINI, respectively. It
is found that the isoscaling parameters of both primary and final
products keep no significant change for light fragments, but increases with the
mass for intermediate and heavy products. The dynamical effects on isoscaling
are exhibited by that value decreases a little with the evolution time
of the system, and opposite trend for the heavy products. The secondary decay
effects on isoscaling are reflected in the increasing of the value for
the final products which experiences secondary decay process.
Furthermore the density dependence of the symmetry energy has also been
explored, it is observed that in the low densities the symmetry energy
coefficient has the form of ,
where for both primary and final products, but
have different values for primary and final products. It is also suggested that
it might be more reasonable to describe the density dependence of the symmetry
energy coefficient by the
with , and constant
parameters.Comment: 10 pages, 10 figure
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