1,559 research outputs found

    Charge-carrier balance for highly efficient inverted planar heterojunction perovskite solar cells

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    The charge-carrier balance strategy by interface engineering is employed to optimize the charge-carrier transport in inverted planar heterojunction perovskite solar cells. N,N-Dimethylformamide-treated poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) and poly(methyl methacrylate)-modified PCBM are utilized as the hole and electron selective contacts, respectively, leading to a high power conversion efficiency of 18.72%

    The Effect of Intra-Abdominal Hypertension Incorporating Severe Acute Pancreatitis in a Porcine Model

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    Introduction: Abdominal compartment syndrome (ACS) and intra abdominal hypertension(IAH) are common clinical findings in patients with severe acute pancreatitis(SAP). It is thought that an increased intra abdominal pressure(IAP) is associated with poor prognosis in SAP patients. But the detailed effect of IAH/ACS on different organ system is not clear. The aim of this study was to assess the effect of SAP combined with IAH on hemodynamics, systemic oxygenation, and organ damage in a 12 h lasting porcine model

    Observation of ηc→ωω\eta_c\to\omega\omega in J/ψ→γωωJ/\psi\to\gamma\omega\omega

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    Using a sample of (1310.6±7.0)×106(1310.6\pm7.0)\times10^6 J/ψJ/\psi events recorded with the BESIII detector at the symmetric electron positron collider BEPCII, we report the observation of the decay of the (11S0)(1^1 S_0) charmonium state ηc\eta_c into a pair of ω\omega mesons in the process J/ψ→γωωJ/\psi\to\gamma\omega\omega. The branching fraction is measured for the first time to be B(ηc→ωω)=(2.88±0.10±0.46±0.68)×10−3\mathcal{B}(\eta_c\to\omega\omega)= (2.88\pm0.10\pm0.46\pm0.68)\times10^{-3}, where the first uncertainty is statistical, the second systematic and the third is from the uncertainty of B(J/ψ→γηc)\mathcal{B}(J/\psi\to\gamma\eta_c). The mass and width of the ηc\eta_c are determined as M=(2985.9±0.7±2.1) M=(2985.9\pm0.7\pm2.1)\,MeV/c2c^2 and Γ=(33.8±1.6±4.1) \Gamma=(33.8\pm1.6\pm4.1)\,MeV.Comment: 13 pages, 6 figure

    Observation and study of the decay J/ψ→ϕηη′J/\psi\rightarrow\phi\eta\eta'

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    We report the observation and study of the decay J/ψ→ϕηη′J/\psi\rightarrow\phi\eta\eta' using 1.3×1091.3\times{10^9} J/ψJ/\psi events collected with the BESIII detector. Its branching fraction, including all possible intermediate states, is measured to be (2.32±0.06±0.16)×10−4(2.32\pm0.06\pm0.16)\times{10^{-4}}. We also report evidence for a structure, denoted as XX, in the ϕη′\phi\eta' mass spectrum in the 2.0−2.12.0-2.1 GeV/c2c^2 region. Using two decay modes of the η′\eta' meson (γπ+π−\gamma\pi^+\pi^- and ηπ+π−\eta\pi^+\pi^-), a simultaneous fit to the ϕη′\phi\eta' mass spectra is performed. Assuming the quantum numbers of the XX to be JP=1−J^P = 1^-, its significance is found to be 4.4σ\sigma, with a mass and width of (2002.1±27.5±21.4)(2002.1 \pm 27.5 \pm 21.4) MeV/c2c^2 and (129±17±9)(129 \pm 17 \pm 9) MeV, respectively, and a product branching fraction B(J/ψ→ηX)×B(X→ϕη′)=(9.8±1.2±1.7)×10−5\mathcal{B}(J/\psi\rightarrow\eta{}X)\times{}\mathcal{B}(X\rightarrow\phi\eta')=(9.8 \pm 1.2 \pm 1.7)\times10^{-5}. Alternatively, assuming JP=1+J^P = 1^+, the significance is 3.8σ\sigma, with a mass and width of (2062.8±13.1±7.2)(2062.8 \pm 13.1 \pm 7.2) MeV/c2c^2 and (177±36±35)(177 \pm 36 \pm 35) MeV, respectively, and a product branching fraction B(J/ψ→ηX)×B(X→ϕη′)=(9.6±1.4±2.0)×10−5\mathcal{B}(J/\psi\rightarrow\eta{}X)\times{}\mathcal{B}(X\rightarrow\phi\eta')=(9.6 \pm 1.4 \pm 2.0)\times10^{-5}. The angular distribution of J/ψ→ηXJ/\psi\rightarrow\eta{}X is studied and the two JPJ^P assumptions of the XX cannot be clearly distinguished due to the limited statistics. In all measurements the first uncertainties are statistical and the second systematic.Comment: 10 pages, 6 figures and 4 table

    Evidence of a resonant structure in the e+e−→π+D0D∗−e^+e^-\to \pi^+D^0D^{*-} cross section between 4.05 and 4.60 GeV

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    The cross section of the process e+e−→π+D0D∗−e^+e^-\to \pi^+D^0D^{*-} for center-of-mass energies from 4.05 to 4.60~GeV is measured precisely using data samples collected with the BESIII detector operating at the BEPCII storage ring. Two enhancements are clearly visible in the cross section around 4.23 and 4.40~GeV. Using several models to describe the dressed cross section yields stable parameters for the first enhancement, which has a mass of 4228.6 \pm 4.1 \pm 6.3 \un{MeV}/c^2 and a width of 77.0 \pm 6.8 \pm 6.3 \un{MeV}, where the first uncertainties are statistical and the second ones are systematic. Our resonant mass is consistent with previous observations of the Y(4220)Y(4220) state and the theoretical prediction of a DDˉ1(2420)D\bar{D}_1(2420) molecule. This result is the first observation of Y(4220)Y(4220) associated with an open-charm final state. Fits with three resonance functions with additional Y(4260)Y(4260), Y(4320)Y(4320), Y(4360)Y(4360), ψ(4415)\psi(4415), or a new resonance, do not show significant contributions from either of these resonances. The second enhancement is not from a single known resonance. It could contain contributions from ψ(4415)\psi(4415) and other resonances, and a detailed amplitude analysis is required to better understand this enhancement

    Observation of Ds+→pnˉD^+_s\rightarrow p\bar{n} and confirmation of its large branching fraction

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    The baryonic decay Ds+→pnˉD^+_s\rightarrow p\bar{n} is observed, and the corresponding branching fraction is measured to be (1.21±0.10±0.05)×10−3(1.21\pm0.10\pm0.05)\times10^{-3}, where the first uncertainty is statistical and second systematic. The data sample used in this analysis was collected with the BESIII detector operating at the BEPCII e+e−e^+e^- double-ring collider with a center-of-mass energy of 4.178~GeV and an integrated luminosity of 3.19~fb−1^{-1}. The result confirms the previous measurement by the CLEO Collaboration and is of greatly improved precision, which may deepen our understanding of the dynamical enhancement of the W-annihilation topology in the charmed meson decays

    First observations of hc→h_c \to hadrons

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    Based on (4.48±0.03)×108(4.48 \pm 0.03) \times 10^{8} ψ(3686)\psi(3686) events collected with the BESIII detector, five hch_c hadronic decays are searched for via process ψ(3686)→π0hc\psi(3686) \to \pi^0 h_c. Three of them, hc→ppˉπ+π−h_c \to p \bar{p} \pi^+ \pi^-, π+π−π0\pi^+ \pi^- \pi^0, and 2(π+π−)π02(\pi^+ \pi^-) \pi^0 are observed for the first time, with statistical significances of 7.4σ\sigma, 4.9σ4.9\sigma, and 9.1σ\sigma, and branching fractions of (2.89±0.32±0.55)×10−3(2.89\pm0.32\pm0.55)\times10^{-3}, (1.60±0.40±0.32)×10−3(1.60\pm0.40\pm0.32)\times10^{-3}, and (7.44±0.94±1.56)×10−3(7.44\pm0.94\pm1.56)\times10^{-3}, respectively, where the first uncertainties are statistical and the second systematic. No significant signal is observed for the other two decay modes, and the corresponding upper limits of the branching fractions are determined to be B(hc→3(π+π−)π0)<8.7×10−3B(h_c \to 3(\pi^+ \pi^-) \pi^0)<8.7\times10^{-3} and B(hc→K+K−π+π−)<5.8×10−4B(h_c \to K^+ K^- \pi^+ \pi^-)<5.8\times10^{-4} at 90% confidence level.Comment: 17 pages, 16 figure
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