Characterizing ionic species in PM2.5 and PM10 in four Pearl River Delta cities；South China

IEECAS SKLLQG

Species；valve size；and pretreatment effects on delta O-18 and delta C-13 values of ostracod valves from Lake Qinghai；Qinghai-Tibet Plateau

IEECAS SKLLQG

Contribution of inherent organic carbon to the bulk delta C-13 signal in loess deposits from the arid western Chinese Loess Plateau

IEECAS SKLLQG

delta C-13 variation of C-3 and C-4 plants across an Asian monsoon rainfall gradient in arid northwestern China

IEECAS SKLLQG

Proposal for studying N* resonances with the (p)over-barp -> (p)over-barn pi(+) reaction

A theoretical study of the (p) over barp -> (p) over barn pi(+) reaction for antiproton beam energy from 1 to 4 GeV is made by including contributions from various known N* and Delta* resonances. It is found that for the beam energy around 1.5 GeV, the contribution of the Roper resonance N-(1440)* produced by the t-channel sigma exchange dominates over all other contributions. Since such a reaction can be studied in the forthcoming PANDA experiment at the GSI Facility of Antiproton and Ion Research (FAIR), the reaction will be realistically the cleanest place for studying the properties of the Roper resonance and the best place for looking for other "missing" N* resonances with large coupling to N sigma.

eta-production on the proton via electromagnetic and hadronic probes

The reactions pi(-)p -> eta n and gamma p -> eta p are investigated within a dynamical coupled-channels model of meson production reactions in the nucleon resonance region The meson-baryon channels included are pi N, pi Delta, sigma N, and rho N The direct eta-photoproduction process is studied within a formalism based on a chiral constituent quark model approach, complemented with a one-gluon-exchange mechanism, to take into account the breakdown of the SU(6)circle times O(3) symmetry In the models search, the following known nucleon resonances are embodied S-11(1535), S-11(1650), P-11(1440), P-11(1710), P-13(1720), D-13(1520), D-13(1700), D-15(1675), and F-15(1680). Data for the pi(-)p -> eta n reaction from threshold up to a total center-of-mass energy of W approximate to 2 GeV are satisfactorily reproduced For the photoproduction channel: two additional higher mass known resonances, P-13(1900) and F-15(2000), are also considered However, reproducing the data for gamma p -> eta p requires, within our approach, two new nucleon resonances, for which we extract, mass and width

Topological objects in the O(3) nonlinear sigma model

We study the topological defects in the nonlinear O(3) sigma model in terms of the decomposition of U(1) gauge potential. Time-dependent baby skyrmions are discussed in the (2 + 1)-dimensional spacetime with the CP1 field. Furthermore, we show that there are three kinds of topological defects-vortex lines, point defects and knot exist in the (3 + 1)-dimensional model, and their topological charges, locations and motions are determined by the phi-mapping topological current theory.