95,563 research outputs found

    Octupole degree of freedom for the critical-point candidate nucleus 152^{152}Sm in a reflection-asymmetric relativistic mean-field approach

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    The potential energy surfaces of even-even 146−156^{146-156}Sm are investigated in the constrained reflection-asymmetric relativistic mean-field approach with parameter set PK1. It is shown that the critical-point candidate nucleus 152^{152}Sm marks the shape/phase transition not only from U(5) to SU(3) symmetry, but also from the octupole-deformed ground state in 150^{150}Sm to the quadrupole-deformed ground state in 154^{154}Sm. By including the octupole degree of freedom, an energy gap near the Fermi surface for single-particle levels in 152^{152}Sm with β2=0.14∼0.26\beta_2 = 0.14 \sim 0.26 is found, and the important role of the octupole deformation driving pair ν2f7/2\nu 2f_{7/2} and ν1i13/2\nu 1i_{13/2} is demonstrated.Comment: 11 pages, 3 figure

    Discussion on Event Horizon and Quantum Ergosphere of Evaporating Black Holes in a Tunnelling Framework

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    In this paper, with the Parikh-Wilczek tunnelling framework the positions of the event horizon of the Vaidya black hole and the Vaidya-Bonner black hole are calculated respectively. We find that the event horizon and the apparent horizon of these two black holes correspond respectively to the two turning points of the Hawking radiation tunnelling barrier. That is, the quantum ergosphere coincides with the tunnelling barrier. Our calculation also implies that the Hawking radiation comes from the apparent horizon.Comment: 8 page

    Pressure Dependence of Wall Relaxation in Polarized 3^3He Gaseous Cells

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    We have observed a linear pressure dependence of longitudinal relaxation time (T1T_1) at 4.2 K and 295 K in gaseous 3^3He cells made of either bare pyrex glass or Cs/Rb-coated pyrex due to paramagnetic sites in the cell wall. The paramagnetic wall relaxation is previously thought to be independent of 3^3He pressure. We develop a model to interpret the observed wall relaxation by taking into account the diffusion process, and our model gives a good description of the data

    Robust optimization for energy transactions in multi-microgrids under uncertainty

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    Independent operation of single microgrids (MGs) faces problems such as low self-consumption of local renewable energy, high operation cost and frequent power exchange with the grid. Interconnecting multiple MGs as a multi-microgrid (MMG) is an effective way to improve operational and economic performance. However, ensuring the optimal collaborative operation of a MMG is a challenging problem, especially under disturbances of intermittent renewable energy. In this paper, the economic and collaborative operation of MMGs is formulated as a unit commitment problem to describe the discrete characteristics of energy transaction combinations among MGs. A two-stage adaptive robust optimization based collaborative operation approach for a residential MMG is constructed to derive the scheduling scheme which minimizes the MMG operating cost under the worst realization of uncertain PV output. Transformed by its KKT optimality conditions, the reformulated model is efficiently solved by a column-and-constraint generation (C&CG) method. Case studies verify the effectiveness of the proposed model and evaluate the benefits of energy transactions in MMGs. The results show that the developed MMG operation approach is able to minimize the daily MMG operating cost while mitigating the disturbances of uncertainty in renewable energy sources. Compared to the non-interactive model, the proposed model can not only reduce the MMG operating cost but also mitigate the frequent energy interaction between the MMG and the grid

    Evaluation of the EMC environment generated by a static var compensator

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    Describes an evaluation of the EMC environment generated by a static var compensator

    Impact of pairing correlations on the orientation of the nuclear

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    For the first time, the tilted axis cranking covariant density functional theory with pairing correlations has been formulated and implemented in a fully self-consistent and microscopic way to investigate the evolution of the spin axis and the pairing effects in rotating triaxial nuclei. The measured energy spectrum and transition probabilities for the Nd-135 yrast band are reproduced well without any ad hoc renormalization factors when pairing effects are taken into account. A transition from collective to chiral rotation has been demonstrated. It is found that pairing correlations introduce additional admixtures in the single-particle orbitals, and, thus, influence the structure of tilted axis rotating nuclei by reducing the magnitude of the proton and neutron angular momenta while merging their direction.Comment: 13 pages, 5 figure
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