Preferred Language
Articles
/
bsj-1446
Study of Nonlinear Refraction and Nonlinear Absorption Coefficients of Different CdS Film Thickness by diode laser
...Show More Authors

In the present work, different thicknesses of CdS film were prepared by chemical bath deposition. Z-Scan technique was used to study the nonlinear refractive index and nonlinear absorption coefficients. Linear optical testing were done such as transmission test, and thickness of films were done by the interference fringes (Michelson interferometer). Z-scan experiment was performed at 650nm using CW diode laser and at 532nm wavelength. The results show the effect of self-focusing and defocusing that corresponds with nonlinear refraction n2. The effect of two-photon absorption was also studied, which correspond to the nonlinear absorption coefficient B.

Crossref
View Publication Preview PDF
Quick Preview PDF
Publication Date
Wed Mar 08 2023
Journal Name
Journal Of Wasit For Science And Medicine
Study on physical properties of nanostructured ZnO prepared by pulse laser deposition
...Show More Authors

Zinc Oxide thin film of 2 μm thickness has been grown on glass substrate by pulsed laser deposition technique at substrate temperature of 500 oC under the vacuum pressure of 8×10-2 mbar. The optical properties concerning the absorption, and transmission spectra were studied for the prepared thin film. From the transmission spectra, the optical gap and linear refractive index of the ZnO thin film was determined. The structure of the ZnO thin film was tested with X-Ray diffraction and it was formed to be a polycrystalline with many peaks.

View Publication Preview PDF
Crossref
Publication Date
Tue Feb 12 2019
Journal Name
Iraqi Journal Of Physics
A Study of the generation of laser soliton from spontaneous emission by ring cavity with carbon nanotube
...Show More Authors

We demonstrate a behavior of laser pulse grows through fiber laser inside and output cavity with a soliton fiber laser based on the multi-wall carbon nanotube saturable absorber (SA), we investigate the effects of a saturable absorber parameter on the mode-locking of a realistic Erbium fiber ring laser. Generalized nonlinear Schrodinger equation including the nonlinear effects as gain dispersion, second anomalous group velocity dispersion (GVD), self phase modulation (SPM), and two photon absorption used to describe pulse evolution. An analytical method has been used to understand and to quantify the role of the SA parameter on the propagation dynamics of pulse laser. We compute the chirp, power, width and phase of the soliton for range

... Show More
View Publication Preview PDF
Crossref
Publication Date
Sun Dec 30 2018
Journal Name
Journal Of Engineering
A Cognition Path Planning with a Nonlinear Controller Design for Wheeled Mobile Robot Based on an Intelligent Algorithm
...Show More Authors

This paper presents a cognition path planning with control algorithm design for a nonholonomic wheeled mobile robot based on Particle Swarm Optimization (PSO) algorithm. The aim of this work is to propose the circular roadmap (CRM) method to plan and generate optimal path with free navigation as well as to propose a nonlinear MIMO-PID-MENN controller in order to track the wheeled mobile robot on the reference path. The PSO is used to find an online tune the control parameters of the proposed controller to get the best torques actions for the wheeled mobile robot. The numerical simulation results based on the Matlab package show that the proposed structure has a precise and highly accurate distance of the generated refere

... Show More
View Publication Preview PDF
Crossref (2)
Crossref
Publication Date
Sun Jan 14 2018
Journal Name
Journal Of Engineering
A Nonlinear MIMO-PID Neural Controller Design for Vehicle Lateral Dynamics model based on Modified Elman Neural Network
...Show More Authors

This paper presents a new design of a nonlinear multi-input multi-output PID neural controller of the active brake steering force and the active front steering angle for a 2-DOF vehicle model based on modified Elman recurrent neural. The goal of this work is to achieve the stability and to improve the vehicle dynamic’s performance through achieving the desired yaw rate and reducing the lateral velocity of the vehicle in a minimum time period for preventing the vehicle from slipping out the road curvature by using two active control actions: the front steering angle and the brake steering force. Bacterial forging optimization algorithm is used to adjust the parameters weights of the proposed controller. Simulation resul

... Show More
View Publication Preview PDF
Publication Date
Fri Oct 01 2021
Journal Name
International Journal Of Mechanical Engineering And Robotics Research
Proportional-Derivative PD Vibration Control with Adaptive Approximation Compensator for a Nonlinear Smart Thin Beam Interacting with Fluid
...Show More Authors

This work is concerned with the vibration attenuation of a smart beam interacting with fluid using proportional-derivative PD control and adaptive approximation compensator AAC. The role of the AAC is to improve the PD performance by compensating for unmodelled dynamics using the concept of function approximation technique FAT. The key idea is to represent the unknown parameters using the weighting coefficient and basis function matrices/vectors. The weighting coefficient vector is updated using Lyapunov theory. This controller is applied to a flexible beam provided with surface bonded piezo-patches while the vibrating beam system is submerged in a fluid. Two main effects are considered: 1) axial stretching of the vibrating beam that leads

... Show More
View Publication Preview PDF
Crossref (3)
Crossref
Publication Date
Tue Jan 08 2019
Journal Name
Iraqi Journal Of Physics
Study of structural, optical and electrical properties of thin Ag2Cu2O4 films prepared by pulsed laser deposition
...Show More Authors

The influence of sintering and annealing temperatures on the structural, surface morphology, and optical properties of Ag2Cu2O4 thin films which deposited on glass substrates by pulsed laser deposition method have been studied. Ag2Cu2O4 powders have polycrystalline structure, and the Ag2Cu2O4 phase was appear as low intensity peak at 35.57o which correspond the reflection from (110) plane. Scan electron microscopy images of Ag2Cu2O4 powder has been showed agglomerate of oxide particles with platelets shape. The structure of thin films has been improved with annealing temperature. Atomic Force micrographs of Ag2Cu2O4 films showed uniform, homogenous films and the shape of grains was almost spherical and larger grain size of 97.85 nm has o

... Show More
View Publication Preview PDF
Crossref
Publication Date
Sat Jan 06 2018
Journal Name
American Institute Of Physics
Synthesis and characterization study of n-Bi2O3/p-Si heterojunction dependence on thickness
...Show More Authors

Abstract. In this work, Bi2O3 was deposited as a thin film of different thickness (400, 500, and 600 ±20 nm) by using thermal oxidation at 573 K with ambient oxygen of evaporated bismuth (Bi) thin films in a vacuum on glass substrate and on Si wafer to produce n-Bi2O3/p-Si heterojunction. The effect of thickness on the structural, electrical, surface and optical properties of Bi2O3 thin films was studied. XRD analysis reveals that all the as deposited Bi2O3 films show polycrystalline tetragonal structure, with preferential orientation in the (201) direction, without any change in structure due to increase of film thickness. AFM and SEM images are used to investigate the influences of film thickness on surface properties. The optical measur

... Show More
Preview PDF
Publication Date
Mon Jan 01 2018
Journal Name
Aip Conference Proceedings
Synthesis and characterization study of n-Bi2O3/p-Si heterojunction dependence on thickness
...Show More Authors

View Publication
Scopus (12)
Crossref (13)
Scopus Clarivate Crossref
Publication Date
Sat Apr 01 2023
Journal Name
Baghdad Science Journal
A Study of a-Si:H Absorption Edge Using Dunstan’s Model
...Show More Authors

The optical absorption data of Hydrogenated Amorphous Silicon was analyzed using a Dunstan model of optical absorption in amorphous semiconductors. This model introduces disorder into the band-band absorption through a linear exponential distribution of local energy gaps, and it accounts for both the Urbach and Tauc regions of the optical absorption edge.Compared to other models of similar bases, such as the O’Leary and Guerra models, it is simpler to understand mathematically and has a physical meaning. The optical absorption data of Jackson et al and Maurer et al were successfully interpreted using Dunstan’s model. Useful physical parameters are extracted especially the band to the band energy gap , which is the energy gap in the a

... Show More
View Publication Preview PDF
Scopus Crossref
Publication Date
Fri Jun 18 2004
Journal Name
Iraqi Journal Of Laser
Effect of Operating Temperature on Performance of Obliquely Deposited Bi, Sb and Bi-Sb Semimetal Thin Film Laser Detectors
...Show More Authors

Obliquely deposited (70o) Bi, Sb, and Bi-Sb alloy thin films have been prepared by thermal
resistive technique. Structural properties of these films were studied using XRD. Their resistance and
voltage responsivity for Nd:YAG and CO2 laser pulses have been recorded as function of operating
temperature between 10 oC and 120 oC. It was found that the maximum responsivity for these detectors
can be obtained at 75 oC. On the other hand, the dependence of responsivity on the width of detectors was
investigated.

View Publication Preview PDF