[en] The microscopic effective charges in mirror nuclei ⁵¹Mn and ⁵¹Fe are investigated with the particle-vibration coupling model based on the self-consistent Skyrme-Hartree-Fock and continuum random-phase-approximation approaches. The isovector parts are predicted to be around 0.15, and the proton effective charges are around 1.25 e, which is less than the empirical value of e^eff_p = 1.5 e. The microscopic effective charges in neutron rich ⁵¹Mn are about 10% less than its proton rich mirror. These effective charges are combined with the shell model to calculate the reduced electric quadrupole transition probability B(E2) values in ⁵¹Mn and ⁵¹Fe. It turns out that the microscopic effective charges have well reproduced the B(E2) values and its ratio in the terminating states.

[en] For the colossal dielectric constant mechanism of calcium copper titanate, the most widely accepted model is an inner barrier layer capacitance model. It is said that in polycrystalline calcium copper titanate ceramic, its semiconducting interior grains are surrounded by thin insulating grain boundaries, i.e. internal barrier layer, which has great influence on its dielectric properties. Results of scanning electron microscope (SEM) show that the sample grain boundary is jam like. It is hard for SEM to measure the thickness of the insulating internal barrier layer in grain boundary region. So positron annihilation technique (PAT) was used to characterize the thickness of the internal barrier layer in this work. The research was carried out by co-doping various concentrations of Al/Nb on its Ti⁴⁺ sites to change the microstructure of calcium copper titanate ceramic grain and grain boundary(CaCu₃Ti_4-x Al_0.5x Nb_0.5x O₁₂, x = 0.2%, 0.5%, and 5.0%). PAT results show that the change trends of sample mean lifetime and Doppler parameter S are similar. Besides, the mean lifetime, Doppler parameter S and the longer lifetime component are minimum at x = 0.5%. This implies the thinnest thickness of its barrier layer. The obtained experimental results support the prediction of internal barrier layer capacitance model that describes the origin of the colossal dielectric constant for the calcium copper titanate ceramics. (authors)

[en] Signature splitting and shape coexistence at high spin in the neutron deficient nucleus ¹²⁹Nd are investigated with the configuration-dependent cranked Nilsson-Strutinsky approach. The calculated bands are compared with the observed signature partner bands and very good agreement results at high spin are obtained. The observed deformed bands are confirmed as normal and highly deformed and their properties are explained theoretically. Terminating states in ¹²⁹Nd and other terminations are predicted. There is shape coexistence within the same configuration from low-spin states to high-spin states. Possible normal and highly deformed bands with rotation around the intermediate principal axis in several interesting configurations of ¹²⁹Nd are discussed. The experimental results for ¹³¹Nd are simply discussed and the calculated bands are in good agreement with observed bands at high spin. Triaxial shapes in ¹²⁷Nd with a triaxial deformation of γ ∼ -12deg are predicted and should be observed experimentally. The value of negative γ of π(h_11/2)⁴v(h_11/2)⁷ configuration increases with neutron number increasing in ^127,129,131Nd. The triaxial shape evolutions with neutron number increasing in ^127,129,131Nd and in ^{126,128,130,132}Pr are explained by the strong driving force of specified single particle orbitals towards to triaxial shape

[en] Utilizing the heavy ion,hydrogen and helium triple beam irradiation experiment platform at China Institute of Atomic Energy, the irradiation experiments for the domestic nuclear grade 304NG stainless steel which is a kind of nuclear reactor internal materials were carried out with different doses and different temperatures. The hardness and elastic modulus of the samples before and after irradiation were measured by nano-indentation with continuous stiffness measurement technique. The results show that under 6 dpa, with the increase of irradiation temperature, the irradiation hardening becomes weakened. Under 300 ℃, the irradiation hardening increases with the irradiation dose. After withstanding higher irradiation dose, the irradiation hardening of hydrogen and helium injected range is more significant, indicating the hydrogen and helium enhance hardening effect. (authors)

[en] The parton rescattering effect on the charged hadron forward-backward multiplicity correlation in pp collisions at √s = 200 GeV is studied by a parton and hadron cascade model, PACIAE, based on the PYTHIA model. The calculated multiplicity and pseudorapidity distribution of the final state charged hadrons are well compared with the experimental data. It is found that the final state charged hadron pseudorapidity distribution is different from the initial state charged partons. The parton rescattering effect on the charged hadron forward-backward multiplicity correlation increases with the increasing parton rescattering strength in the center pseudorapidity region (|η| < 1). However, this effect becomes weaker in the outer pseudorapidity region (|η| > 1).

[en] The domestic ZIRLO is a promising candidate of cladding materials for CAP1400. It is necessary to test its radiation properties before its use. In this paper, the radiation properties of the domestic ZIRLO have been studied as functions of irradiation temperature and dose respectively. The experiment was performed at the HI-13 tandem accelerator of China Institute of Atomic Energy by using 80 MeV Ni ions at different temperature and different dose. The transmission electron microscopy, electron dispersive spectroscopy and nano-indentation were used to characterize the radiation damage. The experimental results show that the precipitates are uniformly distributed at 10 dpa and 300 ℃, while at 700 ℃ the number of precipitates is reduced. Among all the precipitates, Nb is the dominant element. Hardening phenomenon was also observed after irradiation, the higher the radiation dose, the higher the degree of hardening, and it illustrates a decreasing tendency with the increasing of the irradiation temperature. (authors)

[en] Rotational structures at ultrahigh spin in ^157,158,159Er have been investigated with the configuration-dependent cranked Nilsson-Strutinsky approach. Configurations of observed bands are assigned and the corresponding deformations are given theoretically. The calculations suggest that one of ultrahigh spin bands in ¹⁵⁸Er is triaxial highly deformed and the other is normal-deformed, while both ultrahigh spin bands in ¹⁵⁷Er are suggested to be triaxial highly deformed. The possible ultrahigh spin bands in ¹⁵⁹Er are predicted to be triaxial highly deformed and have shape coexistence in the same configuration. The configurations with two neutron holes in the N_osc=4 orbitals and two neutron holes in the h_11/2 orbitals in ¹⁵⁹Er are favoured for ultrahigh spin states but unfavoured for band termination, which is similar to ultrahigh spin bands in ^157,158Er. (authors)

[en] Rotational structures at ultrahigh spin in ^157,158,159Er have been investigated with the configuration-dependent cranked Nilsson-Strutinsky approach. Configurations of observed bands are assigned and the corresponding deformations are given theoretically. The calculations suggest that one of ultrahigh spin bands in ¹⁶⁸Er is triaxial highly deformed and the other is normal-deformed, while both ultrahigh spin bands in ¹⁵⁷Er are suggested to be triaxial highly deformed. The possible ultrahigh spin bands in ¹⁵⁹Er are predicted to be triaxial highly deformed and have shape coexistence in the same configuration. The configurations with two neutron holes in the N_osc = 4 orbitals and two neutron holes in the h_11/2 orbitals in ¹⁵⁹Er are favoured for ultrahigh spin states but unfavoured for band termination, which is similar to ultrahigh spin bands in ^157,158Er. (authors)

[en] The strength of charged particle forward-backward multiplicity correlation in p-barp and pp collisions at √(s)=200GeV is studied by the PYTHIA model and compared with the UA5 and STAR data correspondingly. It turns out that a factor of 3-4 apparent discrepancy between UA5 and STAR data can be attributed to the differences in detector acceptance and observing bin width. We have also studied the centrality bin size dependence of the correlation strength in 0-10 to 0-5 and to 5% most central Au+Au collisions at √(s_NN)=200GeV with the PACIAE model. It turns out that the correlation strength decreases with decreasing centrality bin size monotonously.

[en] The polarization charges in ^44,46,48Ti are studied by the microscopic particle-vibration model and used to investigate the electric quadrupole transitions of the yrast terminating bands. The validity of the commonly used empirical effective charges in the pf shell-model calculations is confirmed. The quadrupole transition probabilities B(E2,I→I-2) and electromagnetic moments are reasonably well reproduced compared with experimental results. It is found that a globally decreasing B(E2) is accompanied with convergence of valence particles into the 1f_7/2 shell when approaching the terminating states. The I=6⁺ state in ⁴⁸Ti shows an exotic behavior with an irregularity of B(E2) and sign change of electromagnetic moments, which is related to a neutron-dominant prolate shape.