[en] Highlights: • The M/W shape rational solitary wave solutions and rogue wave solutions of coupled Hirota equations are given. • The baseband modulational stability theory is established in the defocusing coupled Hirota model. • The M/W shape rational solitary wave can be explained by the baseband modulational stability theory. - Abstract: We derive and study a general rational solution of a coupled defocusing Hirota equation which can be used to describe evolution of light in a two-mode fiber with defocusing Kerr effect and some certain high-order effects. We find some new excitation patterns in the model, such as M-shaped soliton, W-shaped soliton, anti-eye-shaped rogue wave and four-petaled flower rogue wave. The results are compared with the solutions obtained in other coupled systems like vector nonlinear Schrödinger equation, coupled focusing Hirota and Sasa–Satsuma equations. We explain the new characters by modulational instability properties. This further indicates that rational solution does not necessarily correspond to rogue wave excitation dynamics and the quantitative relation between nonlinear excitations and modulational instability should exist.

[en] We report a photoelectron spectroscopy and density functional theory (DFT) study on the electronic and structural properties of Nb3-, Nb3O-, Nb3O2-, and the corresponding neutrals. Well-resolved photoelectron spectra are obtained for the anion clusters at different photon energies and are compared with DFT calculations to elucidate their structures and chemical bonding. We find that Nb3 - possesses a C2V (3A2) structure, and Nb3 is a scalene Cs (2A(double_prime)) triangle. Both Nb3O- and Nb3O are found to have C2V structures, in which the O atom bridges two Nb atoms in a Nb3 triangle. The ground-state of Nb3O2 - is found surprisingly to be a low symmetry C1 (1A) structure, which contains a bridging and a terminal O atom. Molecular orbital analyses are carried out to understand the structures and bonding of the three clusters and provide insights into the sequential oxidation from Nb3- to Nb3O2-. The terminal NbdO unit is common in niobia catalysts, and the Nb3O2- cluster with a NbdO unit may be viewed as a molecular model for the catalytic sites or the initial oxidation of a Nb surface.

[en] We report a combined photoelectron spectroscopy (PES) and density functional theory (DFT) study on a series of tri-tantalum oxide clusters, Ta3On-. Well-resolved PES spectra are obtained for Ta3On- (n = 1-8) at several detachment photon energies, yielding electronic structure information which is used to compare with the DFT calculations. A trend of sequential oxidation is observed as a function of O content until Ta3O8-, which is a stoichiometric cluster. Extensive DFT calculations are performed in search of the lowest energy structures for both the anions and neutrals. The first three O atoms are shown to successively occupy the bridging sites in the Ta3 triangle. The next three O atoms each occupy a terminal site, with the seventh and eighth O atoms forming a double-bridge and a double-terminal, respectively. The Ta3O7- anion is found to possess a localized electron pair on a single Ta center, making it an interesting molecular model for Ta3+ surface sites. Molecular orbital analyses are performed to elucidate the chemical bonding in the Ta3On- clusters.

[en] The electronic structure and chemical bonding in the Ta₃^- cluster are investigated using photoelectron spectroscopy and density functional theory calculations. Photoelectron spectra are obtained for Ta₃^- at four photon energies: 532, 355, 266 and 193 nm. While congested spectra are observed at high electron binding energies, several low-lying electronic transitions are well resolved and compared with the theoretical calculations. The electron affinity of Ta₃ is determined to be 1.35 ± 0.03 eV. Extensive density functional calculations are performed at the B3LYP/Stuttgart +2f1g level to locate the ground state and low-lying isomers for Ta₃ and Ta₃^-. The ground state for the Ta₃^- anion is shown to be a quintet (⁵A(prime)₁) with D_3h symmetry, whereas two nearly isoenergetic states, C_2v (⁴A₁) and D_3h (⁶A₁(prime)), are found to compete for the ground state for neutral Ta₃. A detailed molecular orbital analysis is performed to elucidate the chemical boding in Ta₃^-, which is found to possess multiple d-orbital aromaticity, commensurate with its highly symmetric D_3h structure

[en] This article introduces the content, function, characteristics and development trend of EMF area monitoring, analyzes and discuses the various options and methods of EMF area monitoring. (authors)

[en] In recent years, with the deepening of nuclear and radiation safety supervision, great advances have been made in nuclear application environmental impact assessment in Jiangsu province. But some problems and deficiencies still exist in management. This paper describes the present management situation of nuclear application environmental impact assessment, analysis and discusses the existing problems as well as their countermeasures. (authors)

[en] We report a systematic and comprehensive investigation of the electronic structures and chemical bonding in a series of ditungsten oxide clusters, W₂O_n^- and W₂O_n (n = 1-6), using anion photoelectron spectroscopy and density functional theory (DFT) calculations. Well-resolved photoelectron spectra were obtained at several photon energies (2.331, 3.496, 4.661, 6.424, and 7.866 eV) and W 5d-based spectral features were clearly observed and distinguished from O 2p-based features. More complicated spectral features were observed for the oxygen-deficient clusters due to the W 5d electrons. With increasing oxygen content in W₂O_n^-, the photoelectron spectra were observed to shift gradually to higher binding energies, accompanied by a decreasing number of W 5d-derived features. A behavior of sequential oxidation as a result of charge transfers from W to O was clearly observed. A large energy gap (2.8 eV) was observed in the spectrum of W₂O₆^-, indicating the high electronic stability of the stoichiometric W₂O₆ molecule. Extensive DFT calculations were carried out to search for the most stable structures of both the anion and neutral clusters. Time-dependent DFT method was used to compute the vertical detachment energies and compare to the experimental data. Molecular orbitals were used to analyze the chemical bonding in the ditungsten oxide clusters and elucidate their electronic and structural evolution

[en] It gives a contrast of the principles, methods, advantages and disadvantages of nuclear detector in X-γ radiation monitoring, and brief introduction of the range of different applications of X-γ radiation dose rate meter and purchase points in order to bring more reference value on purchase, use and maintenance the nuclear detector for monitoring personal. (authors)

[en] In order to carry out power transient tests for PWR fuel element in China Advanced Research Reactor (CARR), the research and conceptual design of 3He pressure control loop were completed. The working principle, design parameters and technological flow of the loop were described. It is seen that the a He loop can adjust the power of the tested PWR fuel element rapidly, evenly and flexibly and it is an optimal path to realize the power transient regulation for tested PWR fuel. (authors)

[en] U₃Si₂-Al Dispersion Fuel is one of the important fuel used in the research and testing reactors in the world. The objective of the experiment is investigation of the structure stability of the fuel. The experiment is different from the previous experiments in which the samples are tested for 168 hours in the boiling water of 100 degree C. In this experiment the samples are tested for 168 hours under the conditions to simulate CARR operation for which the water velocity is 10 m/s, and fuel temperature is 154 degree C. The samples are divided three groups, the first group without exposed fuel, the second with the smaller area of exposed fuel, and the third with the bigger area of exposed fuel. The Measurement of the uranium content in the water and the sample weight is used to investigate the structure stability of the fuel, and the anti-corrosion performance of the fuel. (authors)