Static and dynamic aspects of the fission process of 226 Th are analyzed in a self-consistent framework based on relativistic energy density functionals. Constrained relativistic mean-field (RMF) calculations in the collective space of axially symmetric quadrupole and octupole deformations, based on the energy density functional PC-PK1 and a δ-force pairing, are performed to determine the potential energy surface of the fissioning nucleus, the scission line, the single-nucleon wave functions, energies and occupation probabilities, as functions of deformation parameters. Induced fission dynamics is described using the time-dependent generator coordinate method in the Gaussian overlap approximation. A collective Schrödinger equation, determined entirely by the microscopic single-nucleon degrees of freedom, propagates adiabatically in time the initial wave packet built by boosting the ground-state solution of the collective Hamiltonian for 226 Th. The position of the scission line and the microscopic input for the collective Hamiltonian are analyzed as functions of the strength of the pairing interaction. The effect of static pairing correlations on the pre-neutron emission charge yields and total kinetic energy of fission fragments is examined in comparison with available data, and the distribution of fission fragments is analyzed for different values of the initial excitation energy. * Electronic address: zpliphy@swu.edu.cn A microscopic description of fission presents one of the most complex problems in lowenergy theoretical nuclear physics [1, 2]. For a comprehensive recent review and an exhaustive list of references, we refer the reader to Ref. [1]. The spontaneous or induced fission process in which a heavy nucleus splits into fragments is out of reach for ab initio methods and, therefore, modern microscopic approaches are based on the framework of nuclear energy density functionals (NEDFs). Nuclear density functional theory (DFT) and its timedependent (TD) generalization have enabled a self-consistent treatment of both static and dynamic aspects of fission [3-11]. The slow large-amplitude collective motion of the compound system that eventually leads to the formation of the final fragments can be described, in a first approximation, as an adiabatic process in which the intrinsic nucleonic degrees of freedom are decoupled from macroscopic collective degrees of freedom such as multipole moments (deformations) of the mass distribution and pairing fields [1].Numerous studies of spontaneous fission, based on NEDFs, have analyzed the effects of the choice of collective coordinates (shape degrees of freedom), approximations used to calculate the collective inertia, and coupling between shape and pairing degrees of freedom on fission half-lives [12][13][14][15][16][17][18]. A quantitative description of induced fission is, in this framework, conceptually and computationally more challenging and this process has been explored less systematically. In particular, several recent studies have used the time-dependent gener...

Quadrupole and octupole deformation energy surfaces, low-energy excitation spectra and transition rates in fourteen isotopic chains: Xe, Ba, Ce, Nd, Sm, Gd, Rn, Ra, Th, U, Pu, Cm, Cf, and Fm, are systematically analyzed using a theoretical framework based on a quadrupole-octupole collective Hamiltonian (QOCH), with parameters determined by constrained reflection-asymmetric and axially-symmetric relativistic mean-field calculations. The microscopic QOCH model based on the PC-PK1 energy density functional and δ-interaction pairing is shown to accurately describe the empirical trend of low-energy quadrupole and octupole collective states, and predicted spectroscopic properties are consistent with recent microscopic calculations based on both relativistic and non-relativistic energy density functionals. Low-energy negative-parity bands, average octupole deformations, and transition rates show evidence for octupole collectivity in both mass regions, for which a microscopic mechanism is discussed in terms of evolution of single-nucleon orbitals with deformation.

It was proposed that Epstein-Barr virus (EBV) is closely associated with nasopharyngeal carcinoma (NPC); however, the molecular mechanisms involved in the effect of EBV on NPC host genes have not yet been well defined. For this study, two sets of microarray experiments, NPC (EBV-free) vs normal epithelial cells and EBV(+) vs EBV(-) NPC arrays, were analyzed and the datasets were cross-compared to identify any correlation between gene clusters involved in EBV targeting and the NPC host gene expression profiles. Statistical analysis revealed that EBV seems to have a preference for targeting more genes from the differentially expressed group in NPC cells than those from the ubiquitously expressed group. Furthermore, this trend is also reflected in log ratios where the EBV target genes of the differentially expressed group origin showed greater log ratios than genes with an origin from the ubiquitously expressed NPC group. Taken together, the genome-wide comparative scanning of EBV and NPC transcriptomes has successfully demonstrated that EBV infection has an intensifying effect on the signals involved in NPC gene expression both in breadth (the majority of the genes) and in depth (greater log ratios).

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This paper has discussed the stress intensity factor solution method of most popular used nuclear equipment design code and published papers. A series of inlet and outlet nozzle of reactor pressure vessel 3-D FEA fracture mechanics models with different size of corner flaw are created by ABQUAS software. Moreover, the crack front has been specially processed by ZENRCAK software. By compare the stress intensity factor solutions of FEA method and the solutions of influence function method for a 1/4 infinite symmetry plate, the influence functions for PWR reactor pressure vessel inlet and outlet nozzle corner flaw solution are obtained.

A 2D nonlinear beam-wave interaction is built to simulate the backward-wave oscillation(BWO) in a Helical traveling wave tube, based on the 1D beam-wave interaction model by taking into account the angular speed which is affected by magnetic field. The normalized oscillation start-up length with different space charge parameter is compared with that obtained from a equivalent circuit model in small signal, showing that they are close to each other. Also, the simulated results are in accordance with the measurements in a 8—18 GHz Helical TWT. The factors affecting the BWO are studied, by which some methods to suppress the BWO are improved.