Thermodynamics of pairing transition in hot nuclei

The pairing correlations in hot nuclei $^{162}$Dy are investigated in terms of the thermodynamical properties by covariant density functional theory. The heat capacities $C_V$ are evaluated in the canonical ensemble theory and the paring correlations are treated by a shell-model-like approach, in which the particle number is conserved exactly. A S-shaped heat capacity curve, which agrees qualitatively with the experimental data, has been obtained and analyzed in details. It is found that the one-pair-broken states play crucial roles in the appearance of the S shape of the heat capacity curve. Moreover, due to the effect of the particle-number conservation, the pairing gap varies smoothly with the temperature, which indicates a gradual transition from the superfluid to the normal state.Comment: 13 pages, 4 figure

Neutrino mu-tau reflection symmetry and its breaking in the minimal seesaw

In this paper, we attempt to implement the neutrino $\mu$-$\tau$ reflection symmetry (which predicts $\theta^{}_{23} = \pi/4$ and $\delta = \pm \pi/2$ as well as trivial Majorana phases) in the minimal seesaw (which enables us to fix the neutrino masses). For some direct (the preliminary experimental hints towards $\theta^{}_{23} \neq \pi/4$ and $\delta \neq - \pi/2$) and indirect (inclusion of the renormalization group equation effect and implementation of the leptogenesis mechanism) reasons, we particularly study the breakings of this symmetry and their phenomenological consequences.Comment: 20 pages, 7 figures, accepted for publication in JHE

Inducing Effect on the Percolation Transition in Complex Networks

Percolation theory concerns the emergence of connected clusters that percolate through a networked system. Previous studies ignored the effect that a node outside the percolating cluster may actively induce its inside neighbours to exit the percolating cluster. Here we study this inducing effect on the classical site percolation and K-core percolation, showing that the inducing effect always causes a discontinuous percolation transition. We precisely predict the percolation threshold and core size for uncorrelated random networks with arbitrary degree distributions. For low-dimensional lattices the percolation threshold fluctuates considerably over realizations, yet we can still predict the core size once the percolation occurs. The core sizes of real-world networks can also be well predicted using degree distribution as the only input. Our work therefore provides a theoretical framework for quantitatively understanding discontinuous breakdown phenomena in various complex systems.Comment: Main text and appendices. Title has been change

Novel Adhesive Anchoring System Through Engineered Interface

This report describes a study of an innovative adhesive anchoring system. The weak link in the load transferring path of adhesive anchors is at adhesive-concrete (A-C) interface; hence, the innovation is about creating threads/grooves in drilled holes in concrete before the holes are filled with adhesive and anchors are installed. The new anchoring system is expected to improve the robustness of A-C interface and the consistence of adhesive anchors. The new adhesive anchoring system was verified in this study using both unconfined and confined pullout tests in uncracked concrete. The tests were divided into to two groups, one using traditional adhesive anchors and the other using the new adhesive anchors, considering two anchor sizes and three hole-cleaning conditions that represent typical practices. Finite element (FE) analyses using ABAQUS were also conducted to simulate the behavior of the adhesive anchors under tensile loading. The nonlinear analyses incorporating surface-to-surface contact, concrete damaged plasticity and nonlinear spring models were found suitable to capture the global and local behavior of the adhesive anchors with pullout bond failure. The test results and analyses showed that the new adhesive anchors greatly improved the capacity and consistence of adhesive anchors. Meanwhile, further studies are needed to validate the benefit of the proposed adhesive anchors under a variety of conditions such as sustained loading and in cracked concrete. It is also critical to develop a feasible tool to facilitate the implementation