Model Development of Quantum Dot Devices for γ Radiation Detection Using Block Diagram Programming

2011 ◽  
Vol 2 (3) ◽  
Author(s):  
Imbaby I. Mahmoud ◽  
Mohamed S. El_Tokhy ◽  
Hussein A. Konber
Keyword(s):  
Computer Simulation ◽  
Quantum Dot ◽  
Block Diagram ◽  
Model Development ◽  
Radiation Detection ◽  
Optical Gain ◽  
Rate Equations ◽  
Modeling Language ◽  
Γ Radiation ◽  
Practical Procedure

The main objective of this paper is to develop a model of quantum dot (QD) devices for incident γ radiation detection. A novel methodology is introduced to characterize the effect of γ radiation on QD detectors. In this methodology, we used VisSim environment along with the block diagram programming procedures. The benefit of using this modeling language is the simplicity of carrying out the performance’s measurement through computer simulation instead of setting up a practical procedure, which is expensive as well as difficult in management. The roles that the parameters of fabrication can play in the characteristics of QDs devices are discussed through developed models implemented by VisSim environment. The rate equations of the QD devices under γ radiation are studied. The effect of incident γ radiation on the optical gain, power, and output photon densities is investigated. The implemented models can help designers and scientists to optimize their devices to meet their requirements.

Modelling of GaN quantum dot terahertz cascade laser

2013 ◽  
Vol 21 (1) ◽  
Author(s):  
A. Asgari ◽  
A. Khorrami
Keyword(s):  
Quantum Dot ◽  
Electric Fields ◽  
Energy Levels ◽  
Optical Gain ◽  
Threshold Current ◽  
Threshold Current Density ◽  
Rate Equations ◽  
Terahertz Waves ◽  
Different Temperatures ◽  
Cascade Lasers

AbstractIn this paper GaN based spherical quantum dot cascade lasers has been modelled, where the generation of the terahertz waves are obtained. The Schrödinger, Poisson, and the laser rate equations have been solved self-consistently including all dominant physical effects such as piezoelectric and spontaneous polarization in nitride-based QDs and the effects of the temperature. The exact value of the energy levels, the wavefunctions, the lifetimes of electron levels, and the lasing frequency are calculated. Also the laser parameters such as the optical gain, the output power and the threshold current density have been calculated at different temperatures and applied electric fields.

Laboratory study and computer model development related to gross solids' movement in combined sewers

1996 ◽  
Vol 33 (9) ◽  
pp. 39-47 ◽  
Author(s):  
John W. Davies ◽  
Yanli Xu ◽  
David Butler
Keyword(s):  
Computer Simulation ◽  
Pipe Flow ◽  
Model Development ◽  
Simulation Models ◽  
Laboratory Studies ◽  
Pilot Model ◽  
Sewer Systems ◽  
Flow Quality ◽  
Computer Simulation Models ◽  
Theoretical Considerations

Significant problems in sewer systems are caused by gross solids, and there is a strong case for their inclusion in computer simulation models of sewer flow quality. The paper describes a project which considered methods of modelling the movement of gross solids in combined sewers. Laboratory studies provided information on advection and deposition of typical gross solids in part-full pipe flow. Theoretical considerations identified aspects of models for gross solids that should differ from those for dissolved and fine suspended pollutants. The proposed methods for gross solids were incorporated in a pilot model, and their effects on simple simulations were considered.

scholarly journals Modeling the Compaction Characteristics of Fine-Grained Soils Blended with Tire-Derived Aggregates

2021 ◽  
Vol 13 (14) ◽  
pp. 7737
Author(s):  
Amin Soltani ◽  
Mahdieh Azimi ◽  
Brendan C. O’Kelly
Keyword(s):  
Energy Levels ◽  
Model Development ◽  
Dry Mass ◽  
Unit Weight ◽  
Power Functions ◽  
Compaction Characteristics ◽  
Practical Applications ◽  
Fine Grained ◽  
Practical Procedure ◽  
Fine Grained Soil

This study aims at modeling the compaction characteristics of fine-grained soils blended with sand-sized (0.075–4.75 mm) recycled tire-derived aggregates (TDAs). Model development and calibration were performed using a large and diverse database of 100 soil–TDA compaction tests (with the TDA-to-soil dry mass ratio ≤ 30%) assembled from the literature. Following a comprehensive statistical analysis, it is demonstrated that the optimum moisture content (OMC) and maximum dry unit weight (MDUW) for soil–TDA blends (across different soil types, TDA particle sizes and compaction energy levels) can be expressed as universal power functions of the OMC and MDUW of the unamended soil, along with the soil to soil–TDA specific gravity ratio. Employing the Bland–Altman analysis, the 95% upper and lower (water content) agreement limits between the predicted and measured OMC values were, respectively, obtained as +1.09% and −1.23%, both of which can be considered negligible for practical applications. For the MDUW predictions, these limits were calculated as +0.67 and −0.71 kN/m3, which (like the OMC) can be deemed acceptable for prediction purposes. Having established the OMC and MDUW of the unamended fine-grained soil, the empirical models proposed in this study offer a practical procedure towards predicting the compaction characteristics of the soil–TDA blends without the hurdles of performing separate laboratory compaction tests, and thus can be employed in practice for preliminary design assessments and/or soil–TDA optimization studies.

SPIN-DEPENDENT BEATS CREATED BY IRRADIATION OF MICROWAVE FIELD THROUGH A QUANTUM DOT

2011 ◽  
Vol 25 (25) ◽  
pp. 2033-2039
Author(s):  
M. BAGHERI TAGANI ◽  
H. RAHIMPOUR SOLEIMANI
Keyword(s):  
Magnetic Field ◽  
Quantum Dot ◽  
Microwave Field ◽  
Spin Current ◽  
Tunneling Magnetoresistance ◽  
Rate Equations ◽  
Spin Accumulation ◽  
Spin Dependent Transport ◽  
Field Temperature ◽  
Dependent Transport

We study spin-dependent transport through a quantum dot with Zeeman split levels coupled to ferromagnetic leads and under influence of microwave irradiation. Current polarization, spin current, spin accumulation and tunneling magnetoresistance are analyzed using nonequilibrium Green's function formalism and rate equations. Spin-dependent beats in spin resolved currents are observed. The effects of magnetic field, temperature and Coulomb interaction on these beats are studied.

Optical Gain of CdSe Quantum Dot Stacks

2002 ◽  
Vol 190 (2) ◽  
pp. 593-597 ◽  
Author(s):  
K. Sebald ◽  
P. Michler ◽  
J. Gutowski ◽  
R. Kr�ger ◽  
T. Passow ◽  
...  
Keyword(s):  
Quantum Dot ◽  
Optical Gain ◽  
Cdse Quantum Dot
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