[en] We study the effective masses of ρ-mesons for different charged states in asymmetric nuclear matter (ANM) using the Quantum Hadrodynamics II model. The closed form analytical results are presented for the effective masses of ρ-mesons. We have shown that the different charged ρ-mesons have mass splitting similar to various charged pions. The effect of the Dirac sea is also examined, and it is found that this effect is very important and leads to a reduction of the different charged ρ-meson masses in ANM. (authors)

[en] Electromigration technology has a wide application in the field of nuclide migration research, which is attributed to its advantage on obtaining nuclide migration parameters fast and accurately. In a traditional electromigration experiment, the ions are forced to the electrode of opposite charge rapidly in a constant electric field, and through the processes of soil cutting, nuclide concentration determination and model fitting, the migration parameters such as molecular diffusion coefficient and dispersity can be got. At present, this method is successfully applied in the migration behavior study of single-species nuclides, but for multiple-species ones it is not applicable. In this paper, a set of centimeter-scale outflow electromigration device was set up and used to carry out the research on the migration behavior of ⁸⁸Sr in Kerjian bentonite, meanwhile a complete set of method for data processing and parameter calculation was established. The outflow method in electromigration study is proved to be feasible, which lays the theory foundation of the research on multiple-species nuclides migration behavior in the future. (authors)

[en] It is important to study the corrosion mechanism of low carbon steel container and the adsorption behavior of plutonium by corrosion products for evaluating the safety of radioactive waste disposal sites. The study of corrosion behavior of low carbon steel packaging container in radioactive waste repository and the adsorption behavior of corrosion products on plutonium can provide theoretical basis for accurate prediction of plutonium migration behavior and safety evaluation of repository. In this paper, the possible corrosion mechanism of packaging container materials is summarized under the condition of waste geological disposal, and the adsorption behavior of plutonium on corrosion products, the main factors affecting the adsorption and the adsorption mechanism are systematically summarized, which provides a reference for further study on the adsorption mechanism of plutonium on corrosion products in the future. (authors)

[en] We perform a numerical simulation on the time evolution of an electronic wave packet in a Weyl semimetal (WSM) slab driven by a magnetic field. We find that the evolution trajectory of the wave packet depends sensitively on its initial spin state. Only with initial spin state identical to that of the Fermi arc state at the surface it localized, does the wave packet evolution demonstrate the characteristic cyclotron orbit of WSM previously predicted from a semiclassical viewpoint. By analyzing the eigen-expansion of the electronic wave packet, we find the chiral Landau levels (LLs) of the WSM slab, as ingredients of the wave packet, to be responsible for establishing the characteristic WSM cyclotron orbit. In contrast, the nonchiral LLs contribute irregular oscillations to the wave packet evolution, going against the formation of a well-defined cyclotron orbit. In addition, the tilted magnetic field does not affect the motion of the electronic wave packet along the Fermi arcs in the momentum space. It does, however, alter the evolution trajectory of the electronic wave packet in real space and spin space. Finally, the energy disalignment of the Weyl nodes results in a 3D cyclotron orbit in real space. (paper)

[en] The current trend of coated conductor development has motivated an increasing need for a novel synthesis route by which a highly epitaxial YBCO film can be readily deposited on buffered substrates. It has been demonstrated that the fluorine-based sol gel approach can produce high quality, epitaxial YBCO thin films that exhibit a superconducting J_c of over 3-5 MA/cm² in self-field, 77 K. In this study we have developed a new fluorine-free sol gel approach (FFSG) as an effective alternative. The advantages of this new approach is three-fold: (1) no HF during the processing that is detrimental to the film; (2) the FFSG solution is much less reactive to the buffer layer, and (3) the microstructure of the YBCO thin film is more uniform and denser than achieved by the fluorine-based method. Using the new FFSG method, the YBCO thin films have been deposited on the LAO substrates. A high J_c on the order of 5 x 10⁵ A/cm² at 77 K and self-field has been reported. Experimental results on film synthesis, and superconducting properties are presented

[en] We theoretically demonstrate the possibility of realizing the valley and subband-selective electronic transport properties if line defects are embedded in an armchair carbon nanotube. The physical mechanism for such an interesting transport property is clearly due to the appearance of the special subband spanning two valleys without dispersion, caused by the presence of the line defect. In contrast to a perfect zigzag-edged graphene nanoribbon, which was previously suggested to be a nanodevice prototype to manipulate the valley and subband degrees of freedom, our structure, the line defect embedded carbon nanotube, is less demanding for the current nanotechnique. Therefore, our theoretical investigation provides an alternative and feasible structure to design carbon-based nanoelectronic devices.

[en] By using the rigorous spectral representation of relativistic random phase approximation, the low-lying excitation of finite nuclei and its longitudinal response function for quasielastic electron scattering are calculated in the σ-ω model of quantum hadrodynamics. It is shown that the reproduction of the correct order of the 1^- and 3^- excitation states of ¹⁶O is due to the contribution of the exchange vertex. There is no significant influence of the retardation effect on the low-lying excitation states. In contrast, the retardation effect plays an important role in the electron scattering process of nuclei. The theoretical longitudinal responses of ¹²C and ⁴⁰Ca, including the contributions of the exchange vertex and the retardation effect, are suppressed and reproduce the experimental data better than the results excluding them. (authors)

[en] Our theoretical investigation indicates that an applied magnetic field can open a gap between the conduction and valence bands of a nodal line semimetal (NLSM), though it is a kind of gapless material in the absence of a magnetic field. The emerging bandgap depends sensitively on the strength and orientation of the magnetic field which implies a tunable and large anisotropy of magnetoresistance in such kinds of topological materials. Following such a theoretical finding, we predict that in some candidates of NSLMs with a single nodal ring, such as the materials of CaP₃ family, a transition between metallic and insulating states driven by a magnetic field is possibly observed experimentally. Consequently, a magnetic field can be viewed as a novel mechanism for metal–insulator transition of solid materials, in additional to the well-known conventional ones such as the Anderson and Mott transitions. (paper)

[en] The study of finite nuclei containing antibaryon(s) in addition to nucleons is an interesting topic in nuclear physics. The calculation of the lifetime of an antibaryon embedded in a nucleus was performed in the framework of the standard quantum field theory. It was shown that the annihilation probability of the antibaryon in nuclei is strongly dependent on the effective masses of mesons involved in the annihilation channels. The contribution of the Dirac sea to the annihilation probability makes the lifetime of the antibaryon short. If the Dirac sea effect is neglected, the lifetime of the bound antibaryon tends to be longer with the nuclear density increasing. Particularly, when the nuclear density is larger than a critical value, the antibaryon may exist stably in a nucleus. (nuclear physics)

[en] In order to measure the migration parameters of nuclides in bentonite more conveniently, an improved through-discharge electromigration method was developed. In this method, the nuclides first were driven by the electric field to migrate through the bentonite column fast, then discharged with the carrier fluid, and finally collected automatically for measurement. Meanwhile, based on the analysis of the important process in the method, the solution equation for deriving the migration parameters of nuclides was established. Furthermore, two kinds of through-discharge electromigration devices were designed in term of the different nuclide sorption behaviors onto the bentonite, and the electromigration breakthrough curves of ⁸⁸Sr and ²³⁹Pu in bentonite were obtained for the first time. The result indicated that the improved electromigration technology was quite efficient for acquiring the migration parameters of ⁸⁸Sr with weak adsorption capacity. However, it was found that more experimental data were needed to support the analysis of ²³⁹Pu migration behavior because of its complex electrochemistry reaction with bentonite. (author)