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Beijing, China

Bai Y.-J.,CAS Institute of Botany | Bai Y.-J.,University of Chinese Academy of Sciences | Chen L.-Q.,China Agricultural University | Ranhotra P.S.,University of Lucknow | And 3 more authors.
Global Change Biology | Year: 2015

The Earth has undergone a significant climate switch from greenhouse to icehouse during the Plio-Pleistocene transition (PPT) around 2.7-2.4 million years ago (Ma), marked by the intensification of the Northern Hemisphere glaciation (NHG) ~2.7 Ma. Evidence based on oceanic CO2 [(CO2)aq], supposed to be in close equilibrium with the atmospheric CO2 [(CO2)atm], suggests that the CO2 decline might drive such climate cooling. However, the rarity of direct evidence from [CO2]atm during the interval prevents determination of the atmospheric CO2 level and further assessment on the impact of its fluctuation. Here, we reconstruct the [CO2]atm level during 2.77-2.52 Ma based on a new developed proxy of stomatal index on Typha orientalis leaves from Shanxi, North China, and depict the first [CO2]atm curve over the past 5 Ma by using stomata-based [CO2]atm data. Comparisons of the terrestrial-based [CO2]atm and the existed marine-based [CO2]aq curves show a similar general trend but with different intensity of fluctuations. Our data reveal that the high peak of [CO2]atm occurred at 2.77-2.52 Ma with a lower [CO2]aq background. The subsequent sharp fall in [CO2]atm level might be responsible for the intensification of the NHG based on their general temporal synchronism. These findings shed a significant light for our understanding toward the [CO2]atm changes and its ecological impact since 5 Ma. © 2014 John Wiley & Sons Ltd. Source


Jiang X.,Beijing Normal University | Yan S.,Beijing Normal University | Yan S.,Beijing Radiation Center | Maruhn J.A.,Goethe University Frankfurt
Physical Review C - Nuclear Physics | Year: 2013

The dynamics of energy dissipation in head-on fusion reactions of mass-symmetric systems at low bombarding energies is studied by exploiting the improved quantum molecular dynamics model. The results indicate that the form and magnitude of the mass parameter and friction coefficient show strong dependence on system size, bombarding energy, and relative distance. The dynamical mass parameter has almost no effect on the friction coefficient. Two-body collisions play an important role in energy dissipation even when the incident energy is much lower than the Fermi energy. The nucleon-nucleon collisions not only attenuate the energy dissipation but also hinder the nucleon transfer process. © 2013 American Physical Society. Source


Li Y.,Beijing Normal University | Yan S.,Beijing Normal University | Yan S.,Beijing Radiation Center | Jiang X.,Beijing Normal University | Wang L.,Beijing Normal University
Nuclear Physics A | Year: 2013

By using the improved quantum molecular dynamics model, the mechanism of ternary breakup reactions is systematically studied with several symmetrical colliding systems. The result shows that the nearly symmetrical ternary breakup occurs in central and semiperipheral reactions and experiences an extremely and sufficiently inelastic collision with the intense nucleon exchanges. The dynamical effects and nucleon-nucleon correlations play very important roles for determining the outcome of the reactions. © 2013 Elsevier B.V. Source


Xie W.-J.,Beijing Normal University | Xie W.-J.,Yuncheng University | Zhang F.-S.,Beijing Normal University | Zhang F.-S.,Beijing Radiation Center | Zhang F.-S.,Accelerator Centre
Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics | Year: 2014

The isospin-dependent quantum molecular dynamics model is used to investigate the nuclear collective flow observables in semicentral 197Au+197Au collisions at 400A MeV. It is found that the calculated results can reproduce both the experimental data and the other theoretical calculations. We find that the cluster production influences the rapidity dependence of directed flow of protons but less influences the results of tritons. Neutron-proton differential collective flows have larger values when taking the neutron effective mass less than the one of protons as compared with the case of neutron effective mass greater than the one of protons at larger rapidities and transverse momenta. Thus neutron-proton differential collective flows are proposed to be a useful probe to the neutron-proton effective mass splitting and the momentum-dependent symmetry potential. © 2014 Elsevier B.V. Source


Sheng Y.-B.,Beijing Normal University | Deng F.-G.,Beijing Normal University | Zhou H.-Y.,Beijing Normal University | Zhou H.-Y.,Beijing Radiation Center
Quantum Information and Computation | Year: 2010

We present a single-photon entanglement concentration protocol for long-distance quantum communication with quantum nondemolition detector. It is the first concentration protocol for single-photon entangled states and it dose not require the two parties of quantum communication to know the accurate information about the coefficient α and β of the less entangled states. Also, it does not resort to sophisticated single-photon detectors, which makes this protocol more feasible in current experiments. Moreover, it can be iterated to get a higher efficiency and yield. All these advantages maybe make this protocol have more practical applications in long-distance quantum communication and quantum internet. © Rinton Press. Source

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