Transition metal complexes of Co(II) and Ni(II) with azo dye 3,5-dimethyl-2-(4-nitrophenylazo)-phenol derived from 4-nitoaniline and3,5-dimethylphenol were synthesized. Characterization of these compounds has been done on the basis of elemental analysis,electronic data, FT-IR,UV-Vis and 1 HNMR, as well as magnetic susceptibility and conductivity measurements. The nature of thecomplexes formed were studies following the mole ratio and continuous variation methods, Beer ' s law obeyed over a concentrationrange (1x10 -4 - 3x10 -4 M). High molar absorbtivity of the complex solutions were observed. From the analytical data, thestoichiomerty of the complexes has been found to be 1:2 (Metal:ligand). On the basis of physicochemical data tetrahedral
... Show MoreExperimental tests were conducted to investigate the thermal performance (cooling effect) of water mist system consisting of 5μm volume median diameter droplets in reducing the heat gain entering a room through the roof and the west wall by reducing the outside surface temperature due to the evaporative cooling effect during the hot dry summer of Baghdad/Iraq. The test period
was Fifty one days during the months May, June, and July 2012. The single test day consists of 16 test hours starting from 8:00 am to 12:00 pm. The results showed a reduction range of 1.71 to 15.5℃ of the roof outside surface temperature and 21.3 to 76.6% reduction in the daily heat flux entering the room through the roof compared with the case of not using w
CdSe quantum dots possess a tuning energy gap which can control gap values according to the size of the quantum dots, this is made the material able to absorb the wavelengths within visible light. A simple model is provided for the absorption coefficient, optical properties, and optical constants for CdSe quantum dots from the size 10nm to 1nm with the range of visible region between (300-730) nm at room temperature. It turns out that there is an absorption threshold for each wavelength, CdSe quantum dots begin to absorb the visible spectrum of 1.4 nm at room temperature for a wavelength of 300 nm. It has been noted that; when the wavelength is increased, the absorption threshold also increases. This applies to the optical propertie
... Show MoreThis research aims to study the effect of different pH values on the growth of CdTe nanoparticles during specific times. The reflux method has been used as a method for preparing CdTe quantum dots. A difference in absorbance and intensities of peaks at pH 10.5 and 11.5 was observed during the reaction period. The growth rate of the NPs (nucleation) was irregular at low pH values. Optical examinations showed that the best growth rate of NPs was at pH value 12.
Cadmium sulphide CdS films with 200 nm have been prepared by thermal evaporation technique on glass substrate at substrate room temperature under vacuum of 10-5mbar.In this paper, the effect of Dielectric Barrier Discharge plasma on the optical properties of the CdS film. The prepared films were exposed to different time intervals (0, 3, 5, 8) min. For every sample, the Absorption A, absorption coefficient α , energy gap Eg ,extinction coefficient K and dielectric constant ε were studied. It is found that the energy gap were decreased with exposure time, and absorption , Absorption coefficient, refractive index, extinction coefficient, dielectric constant increased with time of exposure to the plasma. Our study conside
... Show MoreCdSe thin films were deposited on glass sudstrate by thermal evaporation method with thickness of (300±25%) nm with deposition rate (2±0.1) nm/s and at substrate temperature at (R.T.). XRD analysis reveals that the structure of pure thin films are Hexagonal and polycrystalline with preferential orientation (002). In this research ,we study the effect of doping with (1,2,3)% Aluminum on optical energy gap of (CdSe) thin film . The absorption was studied by using (UV - Visible 1800 spectra photometer ) within the wavelength (300-1100) nm absorption coefficient was calculated as a function of incident photon energy for identify type of electronic transitions it is found that the type of transition is direct , and we calculated the opt
... Show MoreMicroscope images are characterized by a number of specific parameters, the influence of such parameters (intensity, magnification, numerical aperture, diaphragms aperture, segmentation, and edge detecting technique) on measurement in optical microscope images have been determined with using a powerful image processing methods. As one of the most widespread techniques in biological investigation and dynamic process, light compound microscopy has used to analyze the optical properties of biological images. The results indicate that a wide aperture allows maximum resolution and depth of field, but decreases the contrast. While a small aperture improve visibility and contrast but decreases the resolution. The results also show the best perf
... Show MoreCr2O3 thin films have been prepared by spray pyrolysis on a glass substrate. Absorbance and transmittance spectra were recorded in the wavelength range (300-900) nm before and after annealing. The effects of annealing temperature on absorption coefficient, refractive index, extinction coefficient, real and imaginary parts of dielectric constant and optical conductivity were expected. It was found that all these parameters increase as the annealing temperature increased to 550°C.
In this work, the influence of the annealing temperature on the optical properties of the thin films Cadmium Sulphide (CdS) has been studied. Thin films of Cadmium Sulphide (CdS) were made using the Physical Vapor Deposition (PVD) method. The optical properties of annealing temperatures (as deposited, 200, 250, and 300 ) were scrupulous. The UV/VIS spectrophotometer investigated optical parameters such as transmission, the coefficient of absorption and energy gap of the films for the range (400-110 nm) as an assignment of the annealing temperature. The optical properties were calculated as a function of annealed temperature: absorption, transmission, reflection, band gap, coefficient of absorp
... Show MoreIn this work, study the optical properties of composites consisting of poly Methyl Methacrylate and Berry Paper Mulberry. The samples of composites were prepared using casting method .The Berry Paper Mulberry (BPM) was added by different concentrations are (0, 2, 4 and 6)wt.%. The optical properties of composites have been studied in the wavelength range (200-800)nm. The absorption coefficient ,energy gap, refractive index, extinction coefficient and dielectric constants have been determined. The results show that the optical constants change with increase of BPM concentrations .