We study secular stability against a quasi-radial oscillation for rigidly rotating stars with soft equations of state in general relativity. The polytropic equations of state with polytropic index n between 3 and 3.05 are adopted for modeling the rotating stars. The stability is determined in terms of the turning-point method. It is found that (i) for n >∼ 3.04, all the rigidly rotating stars a...

We present numerical results on the hydrodynamic stability of coalescing binary stars in the first post Newtonian(1PN) approximation of general relativity. We pay particular attention to the hydrodynamical instability of corotating binary stars in equilibrium states assuming the stiff polytropic equation of state with the adiabatic constant Γ = 3. In previous 1PN numerical studies on corotating...

Stationary black holes in 5-dimensional Einstein-Maxwell-Chern-Simons theory possess surprising properties. When considering the Chern-Simons coefficient λ as a parameter, two critical values of λ appear: the supergravity value λSG = 1, and the value λ = 2. At λ = 1, supersymmetric black holes with vanishing horizon angular velocity, but finite angular momentum exist. As λ increases beyond λSG ...

We resolve a controversial issue of the stability of composite vortex solitons in self-focusing saturable nonlinear media. Stable vortex solitons with hidden angular momentum, i.e., composed of counter-rotating beams with topological charges +1 and −1, are found, and their linear-stability region is identified. In contrast, the solitons with explicit vorticity are always unstable against splitt...

We present numerical simulations of dynamically unstable mass transfer in a double white dwarf binary with initial mass ratio, q = 0.4. The binary components are approximated as polytropes of index n = 3/2 and the initially synchronously rotating, semi-detached equilibrium binary is evolved hydrodynamically with the gravitational potential being computed through the solution of Poisson’s equati...

OBJECTIVE Vertebral body replacement following corpectomy in thoracic or lumbar spine is performed with titanium mesh cage (TMC) containing any grafts. Radiological changes often occur on follow-up. This study investigated the relationship between the radiological stability and clinical symptoms. METHODS The subjects of this study were 28 patients who underwent corpectomy on the thoracic or l...

A vibration model is proposed and analyzed dynamically to study the selfsynchronization theory of dual-mass vibration system. The differential equations of systematic motion are derived by applying Lagrange’s equations. As two uncertain parameters, the coefficients of instantaneous change of average angular velocity and the phase difference of two exciters are introduced to derive the coupling ...

High efficiency white light-emitting diodes with superior color-mixing have been investigated. It is suggested that the patterned remote phosphor structure could improve the uniformity of angular-dependent correlated color temperature (CCT) and achieve high chromatic stability in wider operating current range, as compared to the conventional remote phosphor coating structure. In this experiment...

Perturbations of rotating relativistic stars can be classified by their behavior under parity. For axial perturbations (r-modes), initial data with negative canonical energy is found with angular dependence e for all values of m ≥ 2 and for arbitrarily slow rotation. This implies instability (or marginal stability) of such perturbations for rotating perfect fluids. This low m-instability is str...