scholarly journals Excised acoustic black holes: The scattering problem in the time domain

2005 ◽  
Vol 72 (8) ◽  
Author(s):  
C. Cherubini ◽  
F. Federici ◽  
S. Succi ◽  
M. P. Tosi
Keyword(s):  
Black Holes ◽  
Time Domain ◽  
Scattering Problem ◽  
The Time Domain ◽  
Acoustic Black Holes

scholarly journals Convergence of the uniaxial PML method for time-domain electromagnetic scattering problems

2021 ◽  
Author(s):  
Changkun Wei ◽  
Jiaqing Yang ◽  
Bo Zhang
Keyword(s):  
Time Domain ◽  
Electromagnetic Scattering ◽  
Scattering Problem ◽  
Three Dimensional ◽  
Scattering Problems ◽  
Laplace Transform Technique ◽  
The Laplace Transform ◽  
Time Domain Electromagnetic ◽  
Numer Anal ◽  
The Time Domain

In this paper, we propose and study the uniaxial perfectly matched layer (PML) method for three-dimensional time-domain electromagnetic scattering problems, which has a great advantage over the spherical one in dealing with problems involving anisotropic scatterers. The truncated uniaxial PML problem is proved to be well-posed and stable, based on the Laplace transform technique and the energy method. Moreover, the $L^2$-norm and $L^{\infty}$-norm error estimates in time are given between the solutions of the original scattering problem and the truncated PML problem, leading to the exponential convergence of the time-domain uniaxial PML method in terms of the thickness and absorbing parameters of the PML layer. The proof depends on the error analysis between the EtM operators for the original scattering problem and the truncated PML problem, which is different from our previous work (SIAM J. Numer. Anal. 58(3) (2020), 1918-1940).

scholarly journals Random time series in astronomy

2013 ◽  
Vol 371 (1984) ◽  
pp. 20110549 ◽  
Author(s):  
Simon Vaughan
Keyword(s):  
Time Series ◽  
Black Holes ◽  
Time Domain ◽  
Gamma Ray ◽  
Power Spectra ◽  
Polarization Angle ◽  
Noise Power ◽  
Future Challenges ◽  
Nearby Galaxies ◽  
The Time Domain

Progress in astronomy comes from interpreting the signals encoded in the light received from distant objects: the distribution of light over the sky (images), over photon wavelength (spectrum), over polarization angle and over time (usually called light curves by astronomers). In the time domain, we see transient events such as supernovae, gamma-ray bursts and other powerful explosions; we see periodic phenomena such as the orbits of planets around nearby stars, radio pulsars and pulsations of stars in nearby galaxies; and we see persistent aperiodic variations (‘noise’) from powerful systems such as accreting black holes. I review just a few of the recent and future challenges in the burgeoning area of time domain astrophysics, with particular attention to persistently variable sources, the recovery of reliable noise power spectra from sparsely sampled time series, higher order properties of accreting black holes, and time delays and correlations in multi-variate time series.

Design and Analysis of A Complete Full Adder Based On Metal-Insulator-Metal (MIM) Waveguide-Based Plasmonic Waves

2020 ◽  
Author(s):  
oraman yoosefi ◽  
Angel Rodríguez
Keyword(s):  
Real Time ◽  
Time Domain ◽  
Scattering Problem ◽  
Logic Gates ◽  
Cavity Resonator ◽  
Full Adder ◽  
Metal Insulator ◽  
Metal Insulator Metal ◽  
Minimum Power Consumption ◽  
The Time Domain

Abstract In this paper, metal-insulator-metal (MIM) plasmonic waveguide structures and a rectangular cavity resonator at a central frequency of 1550 nm were used to propose a complete full adder. Under this circumstances, the system has a fast function with slight variations in real- time or near real-time manner, and this led to its minimum power consumption, while serving in various situations. In this full adder, we benefited from the property of combining resonant waves in the first and second modes, and we managed to obtain a high transmission coefficient in states where the output must be active. This complete full adder operates through designing 4-input AND, XOR, OR, and NOT logic gates, resulting in the design of a complete full adder with low manufacturing complexity and cost relative to ones designed through combining the conventional 2-input AND and OR gates. In comparison of three computational methods, finite‐difference time‐domain (FDTD) is a simple and versatile method. This method directly discretizes the time‐domain partial differential form of Maxwell's equations in various dimensions while using analytical solution in the remaining direction and solving the 3D scattering problem. Therefore, necessary simulations were conducted using FDTD software, and showed a good fit to the results predicted through approximations intended for theoretical relations.

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