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

Quark distributions in nuclei and nuclear effects on nucleon structure functions

Extended quark distribution functions are presented obtained by fitting a large amount of experimental data of the l-A DIS process on the basis of an improved nuclear density model. The experimental data of l-A DIS processes with A >= 3 in the region 0.0010 <= x <= 0.9500 axe quite satisfactorily described by using the extended formulae. Our knowledge of the influence of nuclear matter on the quark distributions is deepened.

Entrance-channel dependence of isospin effects on double n/p ratio in HIC

Within the hadronic transport model IBUU04, we investigate the effect of density-dependent symmetry energy on double neutron/proton (n/p) ratio of free nucleons in heavy ion collisions by taking four isotopic Sn+Sn reaction systems. Especially the entrance-channel asymmetry and impact-parameter dependence of the effect of symmetry energy are discussed. It is found that in both central and semi-central collisions the sensitivity of the double n/p ratio to the density-dependent symmetry energy is more pronounced in neutron-richer systems. Our results also indicate clearly that the effect of symmetry energy is stronger in central collisions than that in semi-central collisions.

Isospin-symmetry breaking effects on the strange electric and magnetic form factors of the nucleon

We examine the electric and magnetic strange form factors of the nucleon in the pseudoscalar-vector SU(3) Skyrme model, with special emphasis on the effects of isospin symmetry breaking (ISB). It is found that ISB has a nontrivial effect on the strange vector form factors of the nucleon and its contribution to the nucleon strangeness is significantly larger than one might naively expect. Our calculations and discussions may be of some significance for the experimental extraction of the authentic strangeness.

Entrance channel effects on the role of isospin-dependent momentum interaction in isospin fractionation in heavy ion collisions

An isospin degree of freedom is inserted into the momentum dependent interaction in the quantum molecular dynamics model to obtain an isospin dependent momentum interaction given in a form practically usable in isospin dependent quantum molecular dynamics model. We investigate the entrance channel effects for the role of isospin momentum dependent interaction on the isospin fractionation ratio and its dynamical mechanism in the intermediate energy heavy ion collisions. It is found that the isospin dependent momentum interaction induces a significant reduction of isospin fractionation ratio under all entrance channel conditions. However the strong dependence of isospin fractionation ratio on the symmetry potential is preserved after considering the isospin degree of freedom in the momentum dependent interaction.

System size and beam energy effects on probing the high-density behavior of nuclear symmetry energy with pion ratio

Based on the isospin-and momentum-dependent hadronic transport model IBUU04, we have investigated the pi(-)/pi(+) ratio in the following three reactions: Ca-48+Ca-48, Sn-124 +Sn-124 and Au-197+Au-197 with nearly the same isospin asymmetry but different masses, at the bombarding energies from 0.25 to 0.6 A GeV. It is shown that the sensitivity of probing the E-sym (rho) with pi(-)/pi(+) increases with increasing the system size or decreasing the beam energy, showing a correlation to the degree of isospin fractionation. Therefore, with a given isospin asymmetry, heavier system at energies near the pion threshold is preferential to study the behavior Of nuclear symmetry energy at supra-saturation densities.

Medium effects on pi(-)/pi(+) in heavy-ion collisions at intermediate energies

Based on the isospin-dependent transport model IBUU and on the scaling model according to nucleon effective mass, effects of elastic and inelastic NN scattering cross-sections on pi(-)/pi(+) in the neutron-rich reaction Ca-48 + Ca-48 at a beam energy of 400MeV/nucleon are studied. It is found that cross-section effects of both NN elastic and inelastic scatterings affect Delta(1232), pi(-) and pi(+) productions as well as the value of pi(-)/pi(+).

Use of Ecosystem Flux Data and a Simulation Model to Examine Seasonal Drought Effects on a Subtropical Coniferous Forest

National Natural Science Foundation of China (NSFC) [30670384, 30590381]

Spatio-temporal changes in annual accumulated temperature in China and the effects on cropping systems, 1980s to 2000

Change in thermal conditions can substantially affect crop growth, cropping systems, agricultural production and land use. In the present study, we used annual accumulated temperatures > 10 degrees C (AAT10) as an indicator to investigate the spatio-temporal changes in thermal conditions across China from the late 1980s to 2000, with a spatial resolution of 1 x 1 km. We also investigated the effects of the spatio-temporal changes on cultivated land use and cropping systems. We found that AAT10 has increased on a national scale since the late 1980s, Particularly, 3.16 x 10(5) km(2) of land moved from the spring wheat zone (AAT10: 1600 to 3400 degrees C) to the winter wheat zone (AAT10: 3400 to 4500 degrees C). Changes in thermal conditions had large influences on cultivated land area and cropping systems. The areas of cultivated land have increased in regions with increasing AAT10, and the cropping rotation index has increased since the late 1980s. Single cropping was replaced by 3 crops in 2 years in many regions, and areas of winter wheat cultivation were shifted northward in some areas, such as in the eastern Inner Mongolia Autonomous Region and in western Liaoning and Jilin Provinces.

Evaluation of ferricyanide effects on microorganisms with multi-methods

In this study, we report the effects of ferricyanide on organisms based on the changes in physiological state and morphology of Escherichia coli (E coli) DH 5 alpha after being pretreated by ferricyanide. The impact on bacterial cell growth and viable rate of exposure to different concentrations of ferricyanide was determined, and the morphology change of E. coli was studied by atomic force microscopy (AFM). Finally, recovery test was used to evaluate the recovery ability of injured cells. The results showed that the effects on growth and morphology of E. coli were negligible when the concentration of ferricyanide was below 25.0 mM. While the results showed 50.8% inhibition of growth in the presence of 50.0 mM ferricyanide for 3 h, 89.6% viability was detected by flow cytometry (FCM) assay. AFM images proved that compact patches appeared on the bacterial surface and protected the bacterial viability. Furthermore, the results revealed that deterioration of bacterial surface closely related to the incubation time from 0.5 to 3 h at 100.0 mM ferricyanide. In the recovery test, microbial cell population and dissolved oxygen individually decreased 36.7% and 28.3% with 25.0 mM ferricyanide.

SOLVENT AND SUBSTITUENT EFFECTS ON THE INTRAMOLECULAR AMIDE HYDROLYSIS OF N-METHYLMALEAMIC ACID

Intramolecular amide hydrolysis of N-methylmaleamic acid is revisited at the B3LYP/6-311G(2df,p)//B3LYP/6-31G(d,p)+ZVPE level, including solvent effects at the CPCM-B3LYP/6-311G(2df,p)//Onsager-B3LYP/6-31G(d,p)+ZPVE level. The concerted reaction mechanism is energetically favorable over stepwise reaction mechanisms in both the gas phase and solution. The calculated reaction barriers are significantly lower in solution than in the gas phase. In addition, it is concluded that the substituents of the four N-methylmaleamic acid derivatives considered herein have a significant effect on the gas-phase reaction barriers but a smaller, or little, effect on the barriers in solution.

Pressure Effects on the Structural, Electronic, and Optical Properties of Si-n@SWCNTs

Well-ordered single, double/four parallel, three/four-strands helical chains, and five-strand helical chain with a single atom chain at the center of Si nanowires (NWs) inside single-walled carbon nanotubes (Si-n@SWCNTs) are obtained by means of molecular dynamics. On the basis of these optimized structures, the structural evolution of Si-n@SWCNTs subjected to axial stress at low temperature is also investigated. Interestingly, the double parallel chains depart at the center and transform into two perpendicular parts, the helical shell transformed into chain, and the strand number of Si NWs increases during the stress load. Through analyzis of pair correlation function (PCF), the density of states (DOS), and the z-axis polarized absorption spectra of Si-n@SWCNTs, we find that the behavior of Si-n@SWCNTs under stress strongly depends on SWCNTs' symmetry, diameter, as well as the shape of Nws, which provide valuable information for potential application in high pressure cases such as seabed cable.