Phase diffusion model of one-dimensional superradiance lattice and its application as controllable high-frequency light reflector

Author(s):  
Sajid Qamar ◽  
Atif Shabbir
2013 ◽  
Vol 183 (1) ◽  
pp. 33-54 ◽  
Author(s):  
Vadim Ya. Pokrovskii ◽  
Sergey G. Zybtsev ◽  
Maksim V. Nikitin ◽  
Irina G. Gorlova ◽  
Venera F. Nasretdinova ◽  
...  

2021 ◽  
Vol 80 (17) ◽  
Author(s):  
G. Romero-Mujalli ◽  
A. Roisenberg ◽  
A. Cordova-Gonzalez ◽  
P. H. P. Stefano

AbstractRadon (Rn), a radioactive element, has especial interest in medical geology because long-term exposure to high concentration is related to lung cancer. In this study, outdoor and indoor radon measurements were conducted in dwellings of the Piquiri Syenite Massif, located in southern Brazil, given the relative high Rn content in soils of this region. Measurements were done using CR-39 detectors and placing them inside and outside dwellings. Moreover, a one-dimensional diffusion model was performed in order to quantify the natural transport of Rn to the air in confined and aerated environments. Results indicate that the region presents relatively low air Rn concentrations, within the environmental limits; however, the health risk might increase in confined and ill-ventilated environments because of transfer from soil and exhalation from ornamental rock-material often found inside dwellings. The main north facies of the syenite, where most of the rock extractions are located, was found to have the highest air Rn concentration because of the higher soil Rn concentration, compared to other facies of the syenite.


Stochastics ◽  
2007 ◽  
Vol 79 (1-2) ◽  
pp. 5-25 ◽  
Author(s):  
P. Babilua ◽  
I. Bokuchava ◽  
B. Dochviri ◽  
M. Shashiashvili

Author(s):  
Doug Garrard ◽  
Milt Davis ◽  
Steve Wehofer ◽  
Gary Cole

The NASA Lewis Research Center (LeRC) and the Arnold Engineering Development Center (AEDC) have developed a closely coupled computer simulation system that provides a one dimensional, high frequency inlet / engine numerical simulation for aircraft propulsion systems. The simulation system, operating under the LeRC-developed Application Portable Parallel Library (APPL), closely coupled a supersonic inlet with a gas turbine engine. The supersonic inlet was modeled using the Large Perturbation Inlet (LAPIN) computer code, and the gas turbine engine was modeled using the Aerodynamic Turbine Engine Code (ATEC). Both LAPIN and ATEC provide a one dimensional, compressible, time dependent flow solution by solving the one dimensional Euler equations for the conservation of mass, momentum, and energy. Source terms are used to model features such as bleed flows, turbomachinery component characteristics, and inlet subsonic spillage while unstarted. High frequency events, such as compressor surge and inlet unstart, can be simulated with a high degree of fidelity. The simulation system was exercised using a supersonic inlet with sixty percent of the supersonic area contraction occurring internally, and a GE J85-13 turbojet engine.


2022 ◽  
Author(s):  
Xiaoyong Lu ◽  
Lide Wang ◽  
Yunfei Li

Abstract The atomic selective multi-step photoionization process is a critical step in laser isotope separation. In this article, we have studied three-step photoionization processes with non-monochromatic laser fields theoretically based on the semi-classical theory. Firstly, three bandwidth models, including the chaotic field model, de-correlation model and phase diffusion model, are introduced into the density matrix equations. The numerical results are made comparisons comprehensively. The phase diffusion model is selected for further simulations in terms of the correspondence degree to physical practice. Subsequently, numerical calculations are carried out to identify the influences of systematic parameters, including laser parameters (Rabi frequencies, bandwidths, relative time delays, frequency detunings) and atomic Doppler broadening, on photoionization processes. In order to determine the optimum match between different systematic parameters, ionization yield of resonant isotope and selectivity factor are adopted as evaluation indexes to guide the design and optimization process. The results in this work can provide a rewarding reference for laser isotope separation.


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