A numerical study of the impact of climate and emission changes on surface ozone over South China in Autumn time in 2000-2050

2012-2013 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

Forest and forest succession in Hong Kong, China

Hong Kong is on the northern margin of the Asian tropics. The original forest cover was cleared centuries ago but secondary forest has developed since 1945 at many sites protected from fire and cutting. There are also older forest patches maintained behind villages for reasons of 'feng shui', the Chinese system of geomancy. All plants >2cm dbh were identified and measured in forty-four 400-m2 plots. Detrended correpondence analysis showed a floristic continuum, with the motane sites (>500m) most distinct and some overlap between lowland post-1945 secondary forest and the feng shui woods. The 30-40 year-old secondary forest is dominated by Persea spp. Montane forest is similar but lacks several common lowland taxa of tropical genera and includes more subtropical taxa. The feng shui woods have the most complex structure and contain some tree species not found in other forest types. Their origin and history is obscure but we suggest that both planting and selective harvesting have had a role in their current species composition.published_or_final_versio

Observation of a ppb mass threshoud enhancement in \psi^\prime\to\pi^+\pi^-J/\psi(J/\psi\to\gamma p\bar{p}) decay

The decay channel $\psi^\prime\to\pi^+\pi^-J/\psi(J/\psi\to\gamma p\bar{p})$ is studied using a sample of $1.06\times 10^8$ $\psi^\prime$ events collected by the BESIII experiment at BEPCII. A strong enhancement at threshold is observed in the $p\bar{p}$ invariant mass spectrum. The enhancement can be fit with an $S$-wave Breit-Wigner resonance function with a resulting peak mass of $M=1861^{+6}_{-13} {\rm (stat)}^{+7}_{-26} {\rm (syst)} {\rm MeV/}c^2$ and a narrow width that is $\Gamma<38 {\rm MeV/}c^2$ at the 90% confidence level. These results are consistent with published BESII results. These mass and width values do not match with those of any known meson resonance.Comment: 5 pages, 3 figures, submitted to Chinese Physics

On the Computational Precision of Finite Element Algorithms in Slope Stability Problems

Although the finite element method (FEM) has been used extensively to analyse the slope stability problems, the computational precision and definition of failure are still two main key concepts of finite element algorithms that attract the attention of researchers. In this paper, the modified Euler algorithm and the explicit modified Euler algorithm with stress corrections are used to analyse two dimensional (2D) slope stability problems with the associated flow rule, based on the shear strength reduction method. The rounded hyperbolic Mohr-Coulomb (M-C) yield surface is applied. Effects of the element type and various definitions of failure on the computational precision of 2D slope stability problems are evaluated. Conclusions can be drawn that the modified Euler scheme is applicable when the factor of safety (FOS) is small; however, the explicit modified Euler algorithm with stress corrections is more precise if the factor of safety is relatively large. The fully integrated quadrilateral isoparametric element is better than the triangular element in terms of the precision. With respect to the definition of failure, the displacement mutation of the characteristic point combining with the continuums of the plastic zone can be regarded as a reliable definition of failure and can be widely used to perform and analyse numerical simulations of slope stability problems

Experimental studies of e + e -→ some charmless processes containing K S0 at √s = 3.773 and 3.65 GeV

We measure the observed cross sections for the charmless processes e + e -→K S0 K - K - K + π ++ c.c., K S0 K - π + η+c.c., K S0 K - π + π + π - η+c.c., K S0 K - K - K + π + η+c.c., K S0 K - K - K + π + π 0+c.c., K S0 K - ρ ++c.c. and K S0 K - π + ρ 0+c.c. We also extract upper limits on the branching fractions for ψ(3770) decays into these final states at 90% C.L. Analyzed data samples correspond to 17.3 pb-1 and 6.5 pb-1 integrated luminosities registered, respectively, at √s = 3.773 and 3.65 GeV, with the BES-II detector at the BEPC collider. © 2009 Springer-Verlag / Società Italiana di Fisica.published_or_final_versionSpringer Open Choice, 21 Feb 201

Measurement of the matrix element for the decay η′→ηπ +π -

The Dalitz plot of η⊃′→ηπ⊃+π⊃- decay is studied using (225.2±2.8)×106 J/ψ events collected with the BESIII detector at the BEPCII e⊃+e⊃- collider. With the largest sample of η⊃′ decays to date, the parameters of the Dalitz plot are determined in a generalized and a linear representation. Also, the branching fraction of J/ψ→γη⊃′ is determined to be (4.84±0.03±0.24)×10⊃-3, where the first error is statistical and the second systematic. © 2011 American Physical Society.published_or_final_versio

Determination of the number of J/ψ events with J/ψ → inclusive decays

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Higher-order multipole amplitude measurement in ψ ′→γχ c2

Using 106×106 ψ ′ events collected with the BESIII detector at the BEPCII storage ring, the higher-order multipole amplitudes in the radiative transition ψ ′→γχ c2→γπ +π -/γK +K - are measured. A fit to the χ c2 production and decay angular distributions yields M2=0.046±0. 010±0.013 and E3=0.015±0.008±0.018, where the first errors are statistical and the second systematic. Here M2 denotes the normalized magnetic quadrupole amplitude and E3 the normalized electric octupole amplitude. This measurement shows evidence for the existence of the M2 signal with 4.4σ statistical significance and is consistent with the charm quark having no anomalous magnetic moment. © 2011 American Physical Society.published_or_final_versio

Search for a Light Sterile Neutrino at Daya Bay

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Improved measurement of the reactor antineutrino flux and spectrum at Daya Bay

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