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Hybrid nanocomposites containing carbon nanotubes (CNTs) and ordered polyaniline (PANI) have been prepared through an in situ polymerization reaction using a single-walled nanotube (SWNT) as template and aniline as reactant. TEM, SEM, XRD, and Raman analyses show that the polyaniline grew along the surface of CNTs forming an ordered chain structure during the SWNT-directed polymerization process. The SWNT/PANI nanocomposites show both higher electrical conductivity and Seebeck coefficient as compared to pure PANI, which could be attributed to the enhanced carrier mobility in the ordered chain structures of the PANI. The maximum electrical conductivity and Seebeck coefficient of composites reach 1.25 x 10(4) S m(-1) and 40 microV K(-1), respectively, and the maximum power factor is up to 2 x 10(-5) W m(-1) K(-2), more than 2 orders of magnitude higher than the pure polyaniline. This study suggests that constructing highly ordered chain structure is a novel and effective way for improving the thermoelectric properties of conducting polymers.

We study the process e + e − → π + π − J/ψ at a center-of-mass energy of 4.260 GeV using a 525 pb −1 data sample collected with the BESIII detector operating at the Beijing Electron Positron Collider. The Born cross section is measured to be (62.9 ± 1.9 ± 3.7) pb, consistent with the production of the Y (4260). We observe a structure at around 3.9 GeV/c 2 in the π ± J/ψ mass spectrum, which we refer to as the Zc(3900). If interpreted as a new particle, it is unusual in that it carries an electric charge and couples to charmonium. A fit to the π ± J/ψ invariant mass spectrum, neglecting interference, results in a mass of (3899.0 ± 3.6 ± 4.9) MeV/c 2 and a width 3 of (46 ± 10 ± 20) MeV. Its production ratio is measured to be R = σ(e + e − →π ± Zc(3900) ∓ →π + π − J/ψ)) σ(e + e − →π + π − J/ψ) = (21.5 ± 3.3 ± 7.5)%. In all measurements the first errors are statistical and the second are systematic. PACS numbers: 14.40.Rt, 14.40.Pq, 13.66.Bc Since its discovery in the initial-state-radiation (ISR) process e + e − → γ ISR π + π − J/ψ [1], and despite its subsequent observations [2][3][4][5], the nature of the Y (4260) state has remained a mystery. Unlike other charmonium states with the same quantum numbers and in the same mass region, such as the ψ (4040) A similar situation has recently become apparent in the bottomonium system above the BB threshold, where there are indications of anomalously large couplings between the Υ(5S) state (or perhaps an unconventional bottomonium state with similar mass, the Y b (10890)) and the π + π − Υ(1S, 2S, 3S) and π + π − h b (1P, 2P ) final states [14,15]. More surprisingly, substructure in these π + π − Υ(1S, 2S, 3S) and π + π − h b (1P, 2P ) decays indicates the possible existence of charged bottomoniumlike states [16], which must have at least four constituent quarks to have a non-zero electric charge, rather than the two in a conventional meson. By analogy, this suggests there may exist interesting substructure in the Y (4260) → π + π − J/ψ process in the charmonium region.In this Letter, we present a study of the process e + e − → π + π − J/ψ at a center-of-mass (CM) energy of √ s = (4.260± 0.001) GeV, which corresponds to the peak of the Y (4260) cross section. We observe a charged structure in the π ± J/ψ invariant mass spectrum, which we refer to as the Z c (3900). The analysis is performed with a 525 pb −1 data sample collected with the BESIII detector, which is described in detail in Ref. [17]. In the studies presented here, we rely only on charged particle tracking in the main drift chamber (MDC) and energy deposition in the electromagnetic calorimeter (EMC).The GEANT4-based Monte Carlo (MC) simulation software, which includes the geometric description of the BE-SIII detector and the detector response, is used to optimize the event selection criteria, determine the detection efficiency, and estimate backgrounds. For the signal process, we use a sample of e + e − → π + π − J/ψ MC events generated assuming the π + π − J/ψ is produced via Y (4260) decays, and using the...

In this paper, we report a facile ultrasonic method to synthesize well-dispersed CoO quantum dots (3-8 nm) on graphene nanosheets at room temperature by employing Co(4)(CO)(12) as cobalt precursor. The prepared CoO/graphene composites displayed high performance as an anode material for lithium-ion battery, such as high reversible lithium storage capacity (1592 mAh g(-1) after 50 cycles), high Coulombic efficiency (over 95%), excellent cycling stability, and high rate capability (1008 mAh g(-1) with a total retention of 77.6% after 50 cycles at a current density of 1000 mA g(-1), dramatically increased from the initial 50 mA g(-1)). The extraordinary performance arises from the structure advantages of the composites: the nanosized CoO quantum dots with high dispersity on conductive graphene substrates supply not only large quantity of accessible active sites for lithium-ion insertion but also good conductivity and short diffusion length for lithium ions, which are beneficial for high capacity and rate capability. Meanwhile, the isolated CoO quantum dots anchored tightly on the graphene nanosheets can effectively circumvent the volume expansion/contraction associated with lithium insertion/extraction during discharge/charge processes, which is good for high capacity as well as cycling stability. Moreover, regarding the anomalous behavior of capacity increase with cycles (activation effect) observed, we proposed a tentative hypothesis stressing the competition between the conductivity increase and the amorphorization of the composite electrodes during cycling in determining the trends of the capacity, in the hope to gain a fuller understanding of the inner working of the novel nanostructured electrode-based lithium-ion batteries.

Researches on flexible thermoelectric materials usually focus on conducting polymers and conducting polymer-based composites; however, it is a great challenge to obtain high thermoelectric properties comparable to inorganic counterparts. Here, we report an n-type Ag2Se film on flexible nylon membrane with an ultrahigh power factor ~987.4 ± 104.1 μWm−1K−2 at 300 K and an excellent flexibility (93% of the original electrical conductivity retention after 1000 bending cycles around a 8-mm diameter rod). The flexibility is attributed to a synergetic effect of the nylon membrane and the Ag2Se film intertwined with numerous high-aspect-ratio Ag2Se grains. A thermoelectric prototype composed of 4-leg of the Ag2Se film generates a voltage and a maximum power of 18 mV and 460 nW, respectively, at a temperature difference of 30 K. This work opens opportunities of searching for high performance thermoelectric film for flexible thermoelectric devices.

The decay J/ψ → ωpp has been studied, using 225.3 × 10 6 J/ψ events accumulated at BESIII. No significant enhancement near the pp invariant-mass threshold (denoted as X(pp)) is observed. The upper limit of the branching fraction B(J/ψ → ωX(pp) → ωpp) is determined to be 3.9 × 10 −6 at the 95% confidence level. The branching fraction of J/ψ → ωpp is measured to be B(J/ψ → ωpp) = (9.0 ± 0.2 (stat.) ± 0.9 (syst.)) × 10 −4 . 124The investigation of the near-threshold pp invariant 125 mass spectrum in other J/ψ decay modes will be helpful 126 in understanding the nature of the observed structure. 127The decay J/ψ → ωpp restricts the isospin of the pp 128 system, and it is helpful to clarify the role of the pp in the return iron yoke of the superconducting magnet. 174The position resolution is about 2 cm. 175The optimization of the event selection and the es- 247The branching fraction of J/ψ → ωpp is calculated 248 according to :(1) where N obs is the number of signal events determined Breit-Wigner function :Here, q is the momentum of the proton in the pp rest where N obs is the number of signal events, and L is the Author's Copy where σ sys. is the total systematic uncertainty which will 299 be described in the next section. The upper limit on the 300 product of branching fractions is B(J/ψ → ωX(pp) → 301 ωpp) < 3.9 × 10 −6 at the 95% C.L.. 302An alternative fit with a Breit-Wigner function includ-for X(pp) is performed. Here, f FSI is the Jülich FSI cor- between data and MC simulation is 2% per charged track. 323The systematic uncertainty from PID is 2% per proton 324(anti-proton). 325The photon detection systematic uncertainty is studied efficiency difference is about 1% for each photon [32, 33]. 329Author's Copy Near-threshold pp invariant-mass spectrum. The signal J/ψ → ωX(pp) → ωpp is described by an acceptanceweighted Breit-Wigner function, and and signal yield is consistent with zero. The dotted line is the shape of the signal which is normalized to five times the estimated upper limit. The dashed line is the non-resonant contribution described by the function f (δ) and the dashed-dotted line is the non ωpp contribution which is estimated from ω sidebands. The solid line is the total contribution of the two components. The hatched area is from the sideband region.Here, 3% is taken as the systematic error for the efficien- ciency between data and MC is 3%, and is taken as the 338 systematic uncertainty caused by the kinematic fit. 339As described above, the yield of J/ψ → ωpp is de- The signal J/ψ → ωX(pp) → ωpp is described by an acceptanceweighted Breit-Wigner function, and and signal yield is consistent with zero. The dashed line is the non-resonant contribution fixed to a phase space MC simulation of J/ψ → ωpp and the dashed-dotted line is the non ωpp contribution which is estimated from ω sidebands. The solid line is the total contribution of the two components. The hatched area is from a phase space MC simulation of J/ψ → ωpp.sented by Figure.

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We study e+e-→π+π-hc at center-of-mass energies from 3.90 to 4.42 GeV by using data samples collected with the BESIII detector operating at the Beijing Electron Positron Collider. The Born cross sections are measured at 13 energies and are found to be of the same order of magnitude as those of e+e-→π+π-J/ψ but with a different line shape. In the π±hc mass spectrum, a distinct structure, referred to as Zc(4020), is observed at 4.02  GeV/c2. The Zc(4020) carries an electric charge and couples to charmonium. A fit to the π±hc invariant mass spectrum, neglecting possible interferences, results in a mass of (4022.9±0.8±2.7)  MeV/c2 and a width of (7.9±2.7±2.6)  MeV for the Zc(4020), where the first errors are statistical and the second systematic. The difference between the parameters of this structure and the Zc(4025) observed in the D*D[over ¯]* final state is within 1.5σ, but whether they are the same state needs further investigation. No significant Zc(3900) signal is observed, and upper limits on the Zc(3900) production cross sections in π±hc at center-of-mass energies of 4.23 and 4.26 GeV are set.