Entanglement on linked boundaries in Chern-Simons theory with generic gauge groups

We study the entanglement for a state on linked torus boundaries in $3d$ Chern-Simons theory with a generic gauge group and present the asymptotic bounds of R\'enyi entropy at two different limits: (i) large Chern-Simons coupling $k$, and (ii) large rank $r$ of the gauge group. These results show that the R\'enyi entropies cannot diverge faster than $\ln k$ and $\ln r$, respectively. We focus on torus links $T(2,2n)$ with topological linking number $n$. The R\'enyi entropy for these links shows a periodic structure in $n$ and vanishes whenever $n = 0 \text{ (mod } \textsf{p})$, where the integer $\textsf{p}$ is a function of coupling $k$ and rank $r$. We highlight that the refined Chern-Simons link invariants can remove such a periodic structure in $n$.Comment: 31 pages, 5 figure

Twisting of a Pristine α-Fe Nanowire: From Wild Dislocation Avalanches to Mild Local Amorphization.

The torsion of pristine α-Fe nanowires was studied by molecular dynamics simulations. Torsion-induced plastic deformation in pristine nanowires is divided into two regimes. Under weak torsion, plastic deformation leads to dislocation nucleation and propagation. Twisting-induced dislocations are mainly 12 screw dislocations in a -oriented nanowire. The nucleation and propagation of these dislocations were found to form avalanches which generate the emission of energy jerks. Their probability distribution function (PDF) showed power laws with mixing between different energy exponents. The mixing stemmed from simultaneous axial and radial dislocation movements. The power-law distribution indicated strongly correlated 'wild' dislocation dynamics. At the end of this regime, the dislocation pattern was frozen, and further twisting of the nanowire did not change the dislocation pattern. Instead, it induced local amorphization at the grip points at the ends of the sample. This "melting" generated highly dampened, mild avalanches. We compared the deformation mechanisms of twinned and pristine α-Fe nanowires under torsion

Global attractors for strongly damped wave equations with displacement dependent damping and nonlinear source term of critical exponent

In this paper the long time behaviour of the solutions of 3-D strongly damped wave equation is studied. It is shown that the semigroup generated by this equation possesses a global attractor in H_{0}^{1}(\Omega)\times L_{2}(\Omega) and then it is proved that this global attractor is a bounded subset of H^{2}(\Omega)\times H^{2}(\Omega) and also a global attractor in H^{2}(\Omega)\cap H_{0}^{1}(\Omega)\times H_{0}^{1}(\Omega)

Comparison of the degradations of diphenamid by homogeneous photolysis and heterogeneous photocatalysis in aqueous solution

2009-2010 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

Effects of dissolved oxygen, pH, and anions on the 2,3-dichlorophenol degradation by photocatalytic reaction with anodic TiO?nanotube films

2008-2009 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

Auto-ignition in turbulent combustion of hydrogen/air mixing layer at high pressure

The present work investigates the dynamic process of autoignition and extinction of flame kernels in a hydrogen/air mixing layer at a pressure of 30 atm. Direct numerical simulation (DNS) is conducted to solve the unsteady compressible flow equations coupled with reduced chemistry and detailed transport. The evolution of ignition kernels is tracked and analysed, focusing on the differences between successful and failed kernels. Parameters such as the temperature, heat release rate, scalar dissipation rate, convective and diffusive heat fluxes are calculated to provide quantitative information about ignition kernel development. The convective and diffusive heat fluxes in the successful and failed cases show marked differences. Finally, chemical explosive mode analysis (CEMA) is conducted to provide additional information

Three-dimensional shock-sulfur hexafluoride bubble interaction

The evolution of shock-sulfur hexafluoride (SF6) bubble interaction is investigated using a detailed three-dimensional numerical simulation. The influences of the end wall distance on the bubble evolution are analyzed by using the high-resolution simulations. The results show that vorticities mainly emerge at the interfaces of the shock wave and the SF6 bubble, and a downstream jet is formed, owing to the impingement of the high pressure in the vicinity of the downstream pole of the bubble and the induction of nearby vorticities. Besides, the big vortices of the SF6 bubble could interact with the walls in the y-direction to increase the bubble volume. When the end wall distance is shortened, a short and wide downstream jet is formed, owing to the untimely interaction of the reflected shock wave with the distorted SF6 bubble. Also, a new upstream jet emerges behind the impingement of the reflected shock wave, and there is no interaction between the distorted SF6 bubble and the wall in the y-direction until a very late time. From a quantitative point of view, the discrepancy between the bubble volume and effective bubble volume is larger in the case with a long end wall distance, which has enhanced vorticities and strengthened bubble-wall interaction. Moreover, the reflected shock wave has a dominant compression effect on the distorted SF6 bubble evolution for the two cases with different end wall distances, but for the case with a longer end wall distance, the bubble-wall interaction has a more significant influence than the influence of vorticities on the bubble volume increase. The computational results demonstrate the three-dimensional effects of shock-SF6 bubble interactions, which have not been seen in previous two-dimensional simulations

Simulating the impact of urban transport infrastructure design on local air quality in Beijing

Urban transport infrastructure can result in the physical, psychological and environmental separation of neighborhoods, public space and pedestrian network, leading to negative impacts on citizens’ daily commutes, social activities and health. In this paper, we simulate the impacts of road network design on individual activity patterns, travel mode choices and air pollution using an agent-based model. The simulation model is applied to a case study in Beijing and the air pollution heat maps are produced for road network designs comparing with the real-time pollution data. This illustrates the potential value of such simulation models which generate activities for a given urban layout and transport network, and shows how human behavior can impact air qualit

Mechanisms for kerogen wettability transition from water-wet to CO2-wet: Implications for CO2 sequestration

Geological CO2 sequestration (GCS) is an essential building block of the global strategy to alleviate greenhouse gas emissions and mitigate the climate change. Injecting CO2 into the shale formations can not only reduce carbon emissions but also enhance oil recovery (EOR). Rock wettability is of great importance to CO2 storage as it determines the efficiency of structural and residual trapping of CO2 and plays a crucial role in CO2-EOR. In this work, molecular dynamics (MD) simulations are adopted to investigate the CO2-H2O-kerogen systems under various CO2 pressures. In a vacuum or under low CO2 pressures, kerogen surface is weakly water-wet thanks to the hydrogen bonding between H2O and kerogen. As CO2 pressure increases, kerogen wettability shifts from water-wet to CO2-wet, because more CO2 molecules accumulate at the H2O-kerogen interface and a distinct CO2 thin film emerges. Density functional theory (DFT) calculations reveal that the O-containing functional groups preferably adsorb H2O molecules over CO2 through hydrogen bonding, which is responsible for the weakly water-wet tendency at low CO2 pressures. In contrast, the carbon skeleton of kerogen exhibits a stronger affinity to CO2, leading to the formation of CO2 thin film on the kerogen surface. The CO2 crowding close to the kerogen surface at high CO2 pressures gives rise to the CO2-wet state. This study provides, for the first time, the fundamental mechanism for the kerogen wettability transition from water-wet to CO2-wet. The work also indicates that wettability of the mature kerogen is more likely to be CO2-wet during GCS, which is unfavorable for capillary trapping of CO2, but is favorable for CO2-EOR

Numerical simulations for optimizing the liquid water transport in the gas diffusion layer and gas channels of a PEMFC

The multiple-relation-time (MRT) lattice Boltzmann method with a high-density-ratio two-phase model was used to simulate liquid water transport in the gas diffusion layer (GDL) and gas channels of a high-current-density fuel cell. The results show the effects of Reynolds number, perforation shapes and locations in the GDL and the angles of the wave-like gas channels on the water transport. The results show that the GDL and the gas channels should be optimized together to improve the water removal rate. In addition, the results show that the water begins running out of the GDL at earlier times as the Reynolds number increases with the times not related to the wave-like gas channel angle or the perforation shape or location. The structural optimization of the perforated GDL and the wave-like gas channels can guide future designs of fuel cells with high current densities