3,356 research outputs found
Precise dd excitations and commensurate intersite Coulomb interactions in the dissimilar cuprate YBa_2Cu_3O_(7-x) and La_(2-x)Sr_xCuO_4
Using high-resolution extreme ultraviolet resonant inelastic X-ray scattering
(EUVRIXS) spectroscopy at Cu M-edge, we observed the doping dependent spectral
shifts of inter-orbital (dd) excitations of YBa_2Cu_3O_(7-x) and
La_(2-x)Sr_xCuO_4. With increasing hole doping level from undoped to optimally
doped superconducting compositions, the leading edge of dd excitations is found
to shift towards lower energy loss in a roughly linear trend that is
irrespective to the cuprate species. The magnitude of energy shift can be
explained by including a 0.15 eV Coulomb attraction between Cu 3d_(x^2-y^2)
electrons and the doped holes on the surrounding oxygens in the atomic
multiplet calculations. The consistent energy shift between distinct cuprate
families suggests that this inter-site Coulomb interaction energy scale is
relatively material-independent, and provides an important reference point for
understanding charge density wave phenomena in the cuprate phase diagram.Comment: 29 pages; 8 figures. Physical Review B, in press. This paper reveals
a Cu 3d-O 2p intersite interaction energy for the first time experimentally.
It also explains why Tc of YBCO is higher than that of LSC
Total Reaction Cross Section in an Isospin-Dependent Quantum Molecular Dynamics (IDQMD) Model
The isospin-dependent quantum molecular dynamics (IDQMD) model is used to
study the total reaction cross section . The energy-dependent Pauli
volumes of neutrons and protons have been discussed and introduced into the
IDQMD calculation to replace the widely used energy-independent Pauli volumes.
The modified IDQMD calculation can reproduce the experimental well
for both stable and exotic nuclei induced reactions. Comparisons of the
calculated induced by with different initial density
distributions have been performed. It is shown that the calculation by using
the experimentally deduced density distribution with a long tail can fit the
experimental excitation function better than that by using the
Skyrme-Hartree-Fock calculated density without long tails. It is also found
that at high energy is sensitive to the long tail of density
distribution.Comment: 4 page, 4 fig
A proposed reaction channel for the synthesis of the superheavy nucleus Z = 109
We apply a statistical-evaporation model (HIVAP) to calculate the cross
sections of superheavy elements, mainly about actinide targets and compare with
some available experimental data. A reaction channel Si + Am is
proposed for the synthesis of the element Z = 109 and the cross section is
estimated.Comment: 4 pages, 2 figures, 2 tables; two typos are corrected in Ref. [12]
and [19
Nernst effect of the new iron-based superconductor LaOFFeAs
We report the first Nernst effect measurement on the new iron-based
superconductor LaOFFeAs . In the normal state, the
Nernst signal is negative and very small. Below a large positive peak
caused by vortex motion is observed. The flux flowing regime is quite large
compared to conventional type-II superconductors. However, a clear deviation of
the Nernst signal from normal state background and an anomalous depression of
off-diagonal thermoelectric current in the normal state between and 50
K are observed. We propose that this anomaly in the normal state Nernst effect
could correlate with the SDW fluctuations.Comment: 8 pages, 4 figures; Latex file changed, references adde
Systematic Review Outcomes of autotransplanted teeth with complete root formation: a systematic review and meta-analysis
Abstract Aim: In this review, we assessed clinical outcomes of autotransplanted teeth with complete root formation and the effects of various influencing factors. Materials and Methods: Pubmed, Scopus, Google scholar and a hand search were used to identify prospective and retrospective cohort studies and case series till February 2013. Using multilevel Poisson regression, the annual failure rate (FR), 1-year and 5-year survival rates (SRs), infection-related root resorption rate (RR), ankylosis rate (AR), the influences of systemic antibiotics (SAs), endodontic and splinting modalities and donor tooth morphology were analysed. Failure was defined as a transplant being lost during follow-up. Results: Twenty-six studies were included. The estimated FR, RR, AR, 1-and 5-year SRs were 2.0%, 2.1%, 1.2%, 98.0% and 90.5%, respectively. The estimated FR was higher in the absence of SA, suture splinting, wire splinting ≤14 days and posterior donors. The estimated RR was higher in the absence of SA, endodontic treatment within post-operative 14 days and anterior/premolar donors. The estimated AR was higher with wire splinting and premolar donors. Conclusions: Tooth autotransplantation with complete root formation is a favourable treatment with rare FR, RR and AR. However, SAs, endodontic and splinting modalities and tooth morphology seemed to influence the outcomes
Ultra-broadband Light Absorption by a Sawtooth Anisotropic Metamaterial Slab
We present an ultra broadband thin-film infrared absorber made of saw-toothed
anisotropic metamaterial. Absorbtivity of higher than 95% at normal incidence
is supported in a wide range of frequencies, where the full absorption width at
half maximum is about 86%. Such property is retained well at a very wide range
of incident angles too. Light of shorter wavelengths are harvested at upper
parts of the sawteeth of smaller widths, while light of longer wavelengths are
trapped at lower parts of larger tooth widths. This phenomenon is explained by
the slowlight modes in anisotropic metamaterial waveguide. Our study can be
applied in the field of designing photovoltaic devices and thermal emitters.Comment: 12 pages, 4 picture
Study of the P-wave charmonium state \chi_{cJ} in \psi(2S) decays
The processes , and have been studied using a sample of produced
decays. We determine the total width of the to be
MeV. We present the first
measurement of the branching fraction , where the first error is statistical and the
second one systematic. Branching fractions of and
are also reported.Comment: 10 pages, revtex, 3 figures, 2 table
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