IOSR-JAP   Volume-8 ~ Issue-6 ~ Nov-Dec 2016

ABSTRACT: In this work, we studied the effects of surface density of quantum dots and the mean size of quantum dots (QDs) on dynamics of quantum dot laser (QDL). Here, detailed theoretical study of the parameters effect on some properties of GaInAsp/InP QDL system at 1.55 μm wavelength. It includes the following variables: the threshold current density, confined level occupancy, internal loss coefficient, optical confinement layer. In addition, it is diagnosed their role to determining the amount of the maximum temperature of laser. By studying a different control ranges of surface density and the mean size of QDs that identified optimum values for them. That gives better stability of the system's work near the room temperature compared to experimental results.

Keywords:: Quantum dot lasers, Mean size of quantum dots, Surface density of QDs, GaInAsP/InP laser.

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[2] R. M. Hassan, C. A. Emshary and S. I. Easa, "Quantum Dot Laser: Turn-on Dynamics and the Operation Characteristics", LAP LAMBERT Academic Publishing, 2016.
[3] G. M. Ali, "Characteristic Temperature and Lowest Excitation Energy of Semiconductor QD laser", MSc. thesis, basrah university, 2015.
[4] G. P. Agrawal and N. K. Dutta, "Long-Wavelength Semiconductor Lasers", 1st ed., Computer Seience and Engineering Series,VNR, Company,New York, 1987.
[5] Yuchang .Wu "Theory of Modulation Response of Semiconductor Quantum Dot Lasers", PhD. thesis, Virginia Polytechnic Institute and State University, USA, 2013.

ABSTRACT: The theory of elastic constant is capable to explain the concept of Hook's law. According to this, a small amount of deformation in a solid is directly proportional to stress and the strain components are linear function of stress components. The ratio of stress to strain is known as the modulus of elasticity. The third and higher order terms are neglected in the case of harmonic approximation. Some derivations from Hook's law at small deformation has been reported by some physicists which is mainly due to the omission of higher order terms of the strain energy. This reason and derivation motivated the workers to focus their attention to Third Oreder Elastic Constants(TOECs).............

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ABSTRACT: Diabetes is the leading cause of blindness in western countries in the productive age groups. For diabetic retinopathy the major risk is the presence of diabetic. Early detection can potentially reduce the risk of blindness. The eye is one of the most important end organs for complications of diabetes. There are two types of ocular diabetic complications: direct and indirect. Diabetic retinopathy is the primary direct complication of diabetes in the eye. There are two main categories of DR, Non-proliferative (Non-PDR) and Proliferative (PDR). In this work a new technique is presented for automatic screening of diabetic Retinopathy based on Comprehensive Spectral-Textural features which are two fundamental patterns elements that can be interpreted by human. To extract spectral features parameters (Bi-spectral invariant features at different angles of orientation)the gray level retina images are subjected to Radon transform which convert the 2D image in to 1D image vector which introduced to the HOS (Higher Order Statistic) Scheme.............

Keywords: CAD, Diabetic retinopathy, Radon transform, Spectral-Textural Features, KNN.

[1]. VishaliGupta,etal, "Diabetic Retinopathy Atlas and Text",Jaypee Brothers Medical Publications ,First edition 2007.
[2]. Vijay M. Mane, Dattatray V. Jadhav, "Progress towards Automated Early Stage Detection of Diabetic Retinopathy: Image Analysis Systems and Potential", Journal of Medical and Biological Engineering, 34(6): 520-527.2014.
[3]. GiriBabuKande, April, 2010. Feature Extraction from Fundus Images to Analyze Diabetic Retinopathy. Research and Development Cell Jawaharlal Nehru Technological University Hyderabad Kukatpally, Hyderabad – 500 085, India.
[4]. A.M. Mendonça et al. 27 Sep 1999.Automatic segmentation of microaneurysms in retinal angiograms of diabetic patients. IEEE International Conference on Image Analysis and Processing.
[5]. AbhirBhalerao et al. 2008. Robust Detection of Microaneurysms for Sight Threatening Retinopathy Screening. IEEE Computer society.

ABSTRACT: Triglycine Sulphate family crystals are best ferro electric materials. They find wide application as pyroelectric detector. Mixed single crystals of TGSxP1-xcrystals were grown by solvent evaporation technique in the present study. The grown crystals were characterized by density, EDS, XRD, Vicker's hardness measurement and TG/DTA measurement. Melting point and Debye temperature were determined and also the activation energy was calculated from the mass change during heating. Mechanical Parameters like Vicker's hardness number, Meyer's Work hardening coefficient and Stiffness constant were also determined from the Vicker's hardness data. The mixed crystals are found to be harder than the end member crystals.

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ABSTRACT: In this paper, the preparation of films Au precipitated sputtering plasma on glass substrates and study the effect of parameters plasma glow discharge and of pressure gas and the time of deposition on the roughness and morphology of the films prepared through a screening X-ray diffraction (XRD) and testing atomic force microscopy (AFM) and electron microscopy scanner (SEM), and it found through analysis of the results marked increase of the thickness of the films as a result of increased pressure gas as well as an increase sputtering time certified the rest of the parameters.As a result of increased the thickness increasingly granular size and thereby increasing the surface roughness, increased more thickness leads to increased homogeneity of the films record............

Keywords: Au films, plasma, sputtering, morphology, roughness.

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ABSTRACT: Effect of difference concentrations on the optical properties of AZO thin films, prepared on glass slides by Sol-gel method .The optical characteristics of the prepared thin films have been investigated by UV/Vis spectrophotometer in the wavelength range (200 – 800) nm .The films have a direct allow electronic transition with optical energy (Eg) values decreased from 3.29eV for AZO 1% thin films to 3.28eV for the AZO 2% films and to 3.04eV for the AZO 3% films. The maximum value of the refractive index (n) for all thin films are given about 2.13. Also the extinction coefficient (K) and the real and imaginary dielectric constants (€1 & €2). The results indicate the films have good characteristics for optoelectronic applications

Keywords: ZnO, thin films, optical properties

[1]. van Deelen, J. , Rendering, H., het Mannetje, H., Huis in 't Veld, B., Theelen, M., Vroon, Z., Poodt, P., Hovestad, A., "Highly improved transparent conductors by combination of TCOs and metallic grids" Proc. 37th IEEE Photovoltaic Specialists Conference 992 - 994 (2010) and refs. Therein.
[2]. Minami, T "Substitution of transparent conducting oxide thin films for indium tin oxide transparent electrode applications" Thin Solid Films 516, 1314 - 1321 ( 2008).
[3]. Andreas Stadler, Materials 2012, 5, 661-683; doi:10.3390/ma5040661.
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[5]. Chang, J.F.; Hon, M.H. The effect of deposition temperature on the properties of Al-doped zinc oxide thin films. Thin Solid Films 2001, 386, 79–86.

ABSTRACT: Background terrestrial radiation survey of South Valley University was carried outusing a digital radiation meter (Thermo FH 40 G-L10 Survey Meter) which is optimizing to measure gamma background radiation.A total of 24 locations were surveyed across the campus for background environmental radiation. About twenty reading or more were taken in each location in survey and then an average computed. The indoor and outdoor mean ambientdoserate for all the location were the same (0.083±0.006)μSv/hr while the mean of indoor annual effective dose rate (IAEDR) andoutdoor annual effective dose rate (OAEDR) were found to be0.583±0.039and0.145±0.01mSv/yr, respectively. IAEDR varies from 0.516mSv/yr to 0.684mSv/yr. For the outdoor measurement, the minimum dose rate 0.123mSv/yrand the maximum dose rate 0.17mSv/yr. It was noticed that the outdoor dose level was lower than the indoor dose level. The obtained results do not indicate any immediate health side effects on the staff and students and the hostcommunitiesandoperating within the recommended safety limit of 1.0mSv/yr.

Keywords: Background Radiation, Equivalent Dose, Ambient dose rate and safety limit.

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ABSTRACT: Optical property of a material is defined as its interaction with electro-magnetic radiation in the visible The aim of this work is to Describe the phenomenon of material according to calculating the results of the experiments and to find optical properties of some samples for silver oxide ( Ag o 2 ),Characterizations the optical properties of the were examined by using a UV-Visible spectrophotometer at normal incident of light nthe wavelength range of 200–1100nm. The band gaps and the refractive index of the samples were calculated from the absorption spectra, The samples all showed high absorption in the visible region with absorption edges in the blue region of the electromagnetic spectrum. Photo activation of silver oxides Ag o 2 in this region causes transition from the ground to excited state, The samples also show high transmittance in the near infrared region and hence could be of use in devices that provide heat and visible light into the house.

Keywords:Ag o 2 , triethanolamine, optical properties.

[1]. X. Y. Zhang, X. Y. Pan, Q. F. Zhang et al., "Synthesis ofsilver oxide nano-scale thin films and photo-activated
dynamicluminescence fromtheir nanoparticles," Acta Physico—ChimicaSinica, vol. 19, no. 3, pp. 203–207, 2003.
[2]. L. A. Peyser, A. E. Vinson, A. P. Bartko, and R. M. Dickson,"Photoactivated fluorescence from individual silver
nanoclusters,"Science, vol. 291, no. 5501, pp. 103–106, 2001.
[3]. N.R.C.Raju, K. J. Kumar, andA. Subrahmanyam, "Silver oxide(AgO) thin films for surface enhanced Raman scattering
(SERS)studies," AIP Conference Proceedings, vol. 1267, pp. 1005–1006,2010.
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pp.322–326, 1998.
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ABSTRACT: Curcumin, the yellow chemical compound found in two forms, keto form and enol form named (1E,6E)-1,7-Bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione (IUPAC), used in food additive, medicine etc. This molecule fluoresces weakly and poorly soluble in water. The absorption and fluorescence spectra of Curcumin dye has been recorded at room temperature (300 K) in solvents of different polarities. The ground state and excited state dipole moments were obtained experimentally from Lippert's, Bakshiev's and Kawski Chamma-Viallet's equations and theoretically from Gaussian 09 software. It was observed that dipole moments of excited state were higher than those of the ground state for the Curcumin dye

Keywords: Excited and ground state dipole moments, Curcumin dye, Solvatochromic method .

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ABSTRACT: In the present work, study on the photoluminescence behavior of Eu3+ in presence of the ligands Phenyl phosphinic acid and Trioctylphosphine oxide have been carried out. Enhancement of photoluminescence intensity as well as yield by more than an order of magnitude in presence of Phenyl phosphinic acid and further enhancement by a factor of 1.1 with the addition of Trioctylphosphine oxide is observed. Quantitative analysis of the PL enhancement and the factors responsible for the enhancement is discussed.

Keywords: Energy transfer, Ligand Sensitization, Optical Material, Photoluminescence, Rare Earth .

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[5] Z. Hnatejko and M. Elbanowski, Complexation, Luminescence and energy transfer of Ln(III) ions with phenylphosphonic acid, J. Alloys Compd. 380, 2004, 181-185.