380 research outputs found

    Capillary-Induced Ge Uniformly Distributed in N-Doped Carbon Nanotubes with Enhanced Li-Storage Performance

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    Germanium (Ge) is a prospective anode material for lithium-ion batteries, as it possesses large theoretical capacity, outstanding lithium-ion diffusivity, and excellent electrical conductivity. Ge suffers from drastic capacity decay and poor rate performance, however, owing to its low electrical conductivity and huge volume expansion during cycling processes. Herein, a novel strategy has been developed to synthesize a Ge at N-doped carbon nanotubes (Ge at N-CNTs) composite with Ge nanoparticles uniformly distributed in the N-CNTs by using capillary action. This unique structure could effectively buffer large volume expansion. When evaluated as an anode material, the Ge at N-CNTs demonstrate enhanced cycling stability and excellent rate capabilities

    Host structural stabilization of Li1.232Mn0.615Ni0.154O2 through K-doping attempt: toward superior electrochemical performances

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    Lithium-rich layered cathodes are known famously for its superior capacity over traditional layered oxides but trapped for lower initial coulombic efficiency, poorer rate capability and worse cyclic stability in spite of diverse attempts. Herein, a new K-stabilized Li-rich layered cathode synthesized through a simple oxalate co-precipitation is reported for its super electrochemical performances. Compared with pristine Li-rich layered cathode, K-stabilized one reaches a higher initial coulombic efficiency of 87% from 76% and outruns for 94% of capacity retention and 244 mAh g-1 of discharge capacity at 0.5C after 100 cycles. Moreover, 133 mAh g-1 of discharge capacity can be delivered even charged at 10C showing a highly-improved rate capability. X-ray diffraction and electrochemical impedance spectroscopy tests show that enlarged Li slab layer caused by K+ accommodation can provide facile Li+ diffusion paths and facilitate Li+ migration from the crystal lattice. As a consequence, the introduction of K+ in the host layered structure can inhibit the detrimental spinel structure growth during cycling. Therefore, the K-stabilized Li-rich layered materials can be considered to be an attractive alternative to meet with the higher power and energy density demands of advanced lithium-ion battery

    Cloning and Characterization of a Putative TAC1 Ortholog Associated with Leaf Angle in Maize (Zea mays L.)

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    BACKGROUND: Modifying plant architecture to increase photosynthesis efficiency and reduce shade avoidance response is very important for further yield improvement when crops are grown in high density. Identification of alleles controlling leaf angle in maize is needed to provide insight into molecular mechanism of leaf development and achieving ideal plant architecture to improve grain yield. METHODOLOGY/PRINCIPAL FINDINGS: The gene cloning was done by using comparative genomics, and then performing real-time polymerase chain reaction (RT-PCR) analysis to assay gene expression. The gene function was validated by sequence dissimilarity analysis and QTL mapping using a functional cleaved amplified polymorphism (CAP). CONCLUSIONS: The leaf angle is controlled by a major quantitative trait locus, ZmTAC1 (Zea mays L. Leaf Angle Control 1). ZmTAC1 has 4 exons encoding a protein with 263 amino acids, and its domains are the same as those of the rice OsTAC1 protein. ZmTAC1 was found to be located in the region of qLA2 by using the CAP marker and the F(2:3) families from the cross between Yu82 and Shen137. Real-time PCR analysis revealed ZmTAC1 expression was the highest in the leaf-sheath pulvinus, less in the leaf and shoot apical meristem, and the lowest in the root. A nucleotide difference in the 5'-untranslated region (UTR) between the compact inbred line Yu82 ("CTCC") and the expanded inbred line Shen137 ("CCCC") influences the expression level of ZmTAC1, further controlling the size of the leaf angle. Sequence verification of the change in the 5'-UTR revealed ZmTAC1 with "CTCC" was present in 13 compact inbred lines and ZmTAC1 with "CCCC" was present in 18 expanded inbred lines, indicating ZmTAC1 had been extensively utilized in breeding with regard to the improvement of the maize plant architecture

    Study of e+e−→2(pp¯) at center-of-mass energies between 4.0 and 4.6 GeV

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    Using data taken at 23 center-of-mass energies between 4.0 and 4.6 GeV with the BESIII detector at the Beijing Electron Positron Collider and with a total integrated luminosity of approximately 15 fb-1, the process e+e-→2(pp¯) is studied for the first time. The Born cross sections for e+e-→2(pp¯) are measured, and no significant structure is observed in the lineshape. The baryon pair (pp and p¯p¯) invariant mass spectra are consistent with phase space, therefore no hexaquark or di-baryon state is found

    Measurement of the Born cross sections for e+e- →η′π+π- at center-of-mass energies between 2.00 and 3.08 GeV

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    The Born cross sections for the process e+e-→η′π+π- at different center-of-mass energies between 2.00 and 3.08 GeV are reported with improved precision from an analysis of data samples collected with the BESIII detector operating at the BEPCII storage ring. An obvious structure is observed in the Born cross section line shape. Fit as a Breit-Wigner resonance, it has a statistical significance of 6.3σ and a mass and width of M=(2111±43±25) MeV/c2 and Γ=(135±34±30) MeV, where the uncertainties are statistical and systematic, respectively. These measured resonance parameters agree with the measurements of BABAR in e+e-→η′π+π- and BESIII in e+e-→ωπ0 within two standard deviations

    Number of J/ψ events at BESIII *

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    Search for the charged lepton flavor violating decay J/ψ→eτJ/\psi\to e\tau

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    A search for the charged lepton flavor violating decay J/ψ→e±τ∓J/\psi\to e^{\pm}\tau^{\mp} with τ∓→π∓π0ντ\tau^{\mp} \to \pi^{\mp}\pi^0\nu_{\tau} is performed with about 1010 billion J/ψJ/ \psi events collected with the BESIII detector at the BEPCII. No significant signal is observed, and an upper limit is set on the branching fraction B(J/ψ→e±τ∓)<7.5×10−8\mathcal{B}(J/\psi\to e^{\pm}\tau^{\mp})<7.5\times10^{-8} at the 90%\% confidence level. This improves the previously published limit by two orders of magnitude.Comment: 9 pages, 4 figures, 2 table

    Search for New Hadronic Decays of hch_c and Observation of hc→K+K−π+π−π0h_c\rightarrow K^{+}K^{-}\pi^{+}\pi^{-}\pi^{0}

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    Ten hadronic final states of the hch_c decays are investigated via the process ψ(3686)→π0hc\psi(3686)\rightarrow \pi^0 h_c, using a data sample of (448.1±2.9)×106(448.1 \pm 2.9) \times 10^6 ψ(3686)\psi(3686) events collected with the BESIII detector. The decay channel hc→K+K−π+π−π0h_c\rightarrow K^{+}K^{-}\pi^{+}\pi^{-}\pi^{0} is observed for the first time with a significance of 6.0σ6.0 \sigma. The corresponding branching fraction is determined to be B(hc→K+K−π+π−π0)=(3.3±0.6±0.6)×10−3\mathcal{B}(h_c\rightarrow K^{+}K^{-}\pi^{+}\pi^{-}\pi^{0}) =(3.3 \pm 0.6 \pm 0.6)\times 10^{-3} (the first uncertainty is statistical and the second systematical). Evidence for the decays hc→π+π−π0ηh_c\rightarrow \pi^{+} \pi^{-} \pi^{0} \eta and hc→KS0K±π∓π+π−h_c\rightarrow K^{0}_{S}K^{\pm}\pi^{\mp}\pi^{+}\pi^{-} is found with a significance of 3.6σ3.6 \sigma and 3.8σ3.8 \sigma, respectively. The corresponding branching fractions (and upper limits) are obtained to be B(hc→π+π−π0η)=(7.2±1.8±1.3)×10−3\mathcal{B}(h_c\rightarrow \pi^{+} \pi^{-} \pi^{0} \eta ) =(7.2 \pm 1.8 \pm 1.3)\times 10^{-3} (<1.8×10−2)(< 1.8 \times 10^{-2}) and B(hc→KS0K±π∓π+π−)=(2.8±0.9±0.5)×10−3\mathcal{B}(h_c\rightarrow K^{0}_{S}K^{\pm}\pi^{\mp}\pi^{+}\pi^{-}) =(2.8 \pm 0.9 \pm 0.5)\times 10^{-3} (<4.7×10−3)(<4.7\times 10^{-3}). Upper limits on the branching fractions for the final states hc→K+K−π0h_c \rightarrow K^{+}K^{-}\pi^{0}, K+K−ηK^{+}K^{-}\eta, K+K−π+π−ηK^{+}K^{-}\pi^{+}\pi^{-}\eta, 2(K+K−)π02(K^{+}K^{-})\pi^{0}, K+K−π0ηK^{+}K^{-}\pi^{0}\eta, KS0K±π∓K^{0}_{S}K^{\pm}\pi^{\mp}, and ppˉπ0π0p\bar{p}\pi^{0}\pi^{0} are determined at a confidence level of 90\%.Comment: 10 pages, 2 figure

    Helicity amplitude analysis of χcJ→ϕϕ\chi_{cJ} \rightarrow \phi\phi

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    Using (447.9 ±\pm 2.3) million ψ\psi(3686) events collected with the BESIII detector, the decays of χcJ→ϕϕ\chi_{cJ} \rightarrow \phi\phi (JJ=0, 1, 2) have been studied via the decay ψ(3686)→γχcJ\psi(3686)\rightarrow\gamma\chi_{cJ}. The branching fractions of the decays χcJ→ϕϕ\chi_{cJ} \rightarrow \phi\phi (JJ=0, 1, 2) are determined to be (8.48±0.26±0.27)×10−4(8.48\pm0.26\pm0.27)\times10^{-4}, (4.36±0.13±0.18)×10−4(4.36\pm0.13\pm0.18)\times10^{-4}, and (13.36±0.29±0.49)×10−4(13.36\pm0.29\pm0.49)\times10^{-4}, respectively, which are the most precise measurements to date. From a helicity amplitude analysis of the process ψ(3686)→γχcJ,χcJ→ϕϕ,ϕ→K+K−\psi(3686) \rightarrow \gamma \chi_{cJ}, \chi_{cJ}\rightarrow \phi\phi, \phi\rightarrow K^{+}K^{-}, the polarization parameters of the χcJ→ϕϕ\chi_{cJ} \rightarrow \phi\phi decays are determined for the first time.Comment: 23 pages, 5 figure

    Measurement of the absolute branching fraction of the inclusive decay Ds+→π+π+π−XD_s^+\to \pi^+\pi^+\pi^- X

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    Using an e+e−e^+ e^- collision data sample with a total integrated luminosity of 3.193.19 fb−1^{-1} collected with the BESIII detector at a center-of-mass energy of 4.178 GeV, the branching fraction of the inclusive decay of the Ds+D_s^+ meson to final states including at least three charged pions is measured for the first time to be B(Ds+→π+π+π−X)=(32.81±0.35stat±0.82syst)%{\cal B}(D_s^+\to\pi^+ \pi^+ \pi^- X) = (32.81 \pm 0.35_{\rm stat} \pm {0.82_{\rm syst}})\%. In this measurement the charged pions from KS0K_S^0 meson decays are excluded. The partial branching fractions of Ds+→π+π+π−XD_s^+\to\pi^+ \pi^+ \pi^- X are also measured as a function of the π+π+π−\pi^+ \pi^+ \pi^- invariant mass.Comment: 13 pages, 4 figure
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