Hawking has shown that the emission of gravitational radiation cannot prevent circular loops of gauged cosmic strings from collapsing into black holes. Here we consider the corresponding question for global strings: can Goldstone boson emission prevent circular loops of global cosmic strings from forming black holes? Our results show that for every value of the string tension there is a certain...

We use finite-difference time-domain (FDTD) simulations to demonstrate enhanced infrared absorption in a photodetector covered with a microstructured metal film consisting of a metal-plasmon grating collector/ concentrator and sub-wavelength detector well; for circular gratings we use radial FDTD, and for linear gratings we use two-dimensional FDTD. We identify a figure of merit to quantify the...

Due to the influence of ground stress, mining disturbance, and other factors, roadway surrounding rock in deep underground engineering such as mines, tunnels, caverns is prone looseness deformation with excavation roadways. In engineering, bolt support frequently employed stabilize rock. this work, a part anchor were taken simplified model anchorage mass, laboratory compression test was perform...

We present a two-dimensional grid-based hydrodynamic simulation of a thin, viscous, locally isothermal corotating disk orbiting an equal-mass Newtonian binary point mass on a fixed circular orbit. We study the structure of the disk aftermultiple viscous times. The binarymaintains a central hole in the viscously relaxed diskwith radius equal to about twice the binary semimajor axis. Disk surface...