In this paper a thin films of selenium was prepare on substrates of n-Si by evaporation in a vacuum technique with thickness about 0.5μm. And then an annealing process was done on samples at two temperature (100 and 200) C ° in a vacuum furnace (10-3 torr).
Some structural, optical and mechanical properties of prepared thin films were measured. Results showed that the prepared film was the crystallization, optical transmittance and micro hardness of the prepared thin films increased significantly after annealing.
In the present research, the electrical properties which included the ac-conductivity (σac), loss tangent of dielectric (tan δ) and real dielectric constant (ε’) are studied for nano polycarbonate in different pressures and frequencies as a function of temperature these properties were studied at selective temperature gradients which are (RT-50-100-150-250)°C. The results of the study showed that the values of dielectric constant and dissipation factor increase with increasing pressure and temperature and decreases by increasing frequency. And the results of electrical conductivity showed that it increases with increasing temperature, pressure and frequency.
Dental clinicians and professionals need an affordable, nontoxic, and effective disinfectant against infectious microorganisms when dealing with the contaminated dental impressions. This study evaluated the efficiency of hypochlorous acid (HOCl) as an antimicrobial disinfectant by spraying technique for the alginate impression materials, compared with sodium hypochlorite, and its effect on dimensional stability and reproduction of details. HOCl with a concentration of 200 ppm for 5 and 10 min was compared with the control group (no treatment) as a negative control and with sodium hypochlorite (% 0.5) as a positive control. Candida albicans, Staphylococcus aureus, and Pseudomonas aeruginosa were selected to assess the antimicrobi
... Show MoreDental clinicians and professionals need an affordable, nontoxic, and effective disinfectant against infectious microorganisms when dealing with the contaminated dental impressions. This study evaluated the efficiency of hypochlorous acid (HOCl) as an antimicrobial disinfectant by spraying technique for the alginate impression materials, compared with sodium hypochlorite, and its effect on dimensional stability and reproduction of details. HOCl with a concentration of 200 ppm for 5 and 10 min was compared with the control group (no treatment) as a negative control and with sodium hypochlorite (% 0.5) as a positive control. Candida albicans, Staphylococcus aureus, and Pseudomonas aeruginosa were selected to assess the antimicrobi
... Show MoreChoosing an appropriate impression material is a challenge for many dentists, yet an essential component to provide an excellent clinical outcome and improve productivity and profit. The purpose of present study was to compare wettability, tear strength and dimensional accuracy of three elastomeric impression materials, with the same consistencies (light-body). Three commercially available light body consistency and regular set 3M ESPE Express polyvinylsiloxane (PVS), 3M ESPE Permadyne polyether (PE), and Identium (ID), impression materials were comparedTear strength test, contact angle test and linear dimensional accuracy were evaluated for three elastic impression material. Among the three experimental groups PE impression materia
... Show MoreIn this research, nanocomposites of poly(methyl methacrylate) (PMMA) and a mixture of nano silica (SiO2) and nano zirconia (ZrO2) were prepared in different weight percentages of the nano fillers to improve some of the properties of PMMA resin to be used as a denture base material. The nano filles were surface modified with a coupling agent and added to the PMMA in different amounts. Impact strength, transverse strength, hardness and roughness were tested for both control and experimental groups. The results indicate that PMMA/silica/zirconia nanocomposites, prepared with 5% by weight of both types of fillers, had a slight increase in impact s
Nanoferrite materials have been synthesized by sol-gel auto combustion method. The effect of doping different percentages of Y2O3 (0.34 µm) on the physical and mechanical properties of selected mixed ferrite [(Li2.5Fe0.5) 0.9(Co4Fe2O4) 0.1] by adding 10% Cobalt ferrite was studied. Physical properties (i.e. .density, porosity and water absorption) were affected by the doping, where the density increased about 32% at 6 wt% Y2O3, while porosity has a drastically decreased about 80% at 6% Y2O3 and has a correlation effect on the mechanical properties(Splitting tensile strength and Vicker
... Show MoreThis search study the effect of particle size of graphite on the mechanical and thermal properties of epoxy composites, where graphite adopted with particle sizes (45,53,75) ?m, respectively, and the percentages by weight (0,1,3,5,7,9)% for each size of this three particle sizes.Mechanical properties represented by the bending (three-point bending) and through which the conclusion is bending stress and modulus of elasticity, thermal properties were either through thermal conductivity tests.The results showed that the ratio(1%) is the maximum value of bending stress at the three particle size and the (45 ?m) is the maximum.Thermal conductivity result show is the maximum value at ratio (1%) of particle size(53 ?m)
Abstract
In this research, the morphology and mechanical properties of (Epoxy/PVC) blend were investigated. (EP/PVC) blend was prepared by manual mixing of epoxy resin with different weight ratios of (Poly vinyl chloride (PVC) after dissolving it in cyclohexanon). Five sheets of polymer blends in wt% included (0%, 5%, 10%, 15% and 20%) of PVC were prepared at room temperature. Tests were carried out to study some mechanical properties for these blends and compared with the properties of pure epoxy. The morphology of the prepared materials was examined to study the compatibility nature between the two polymers under work. It was found that the best ratio of addition is (20%) of PVC.
... Show MoreStudied the optical properties of the membranes CdS thin containing different ratios of ions cadmium to sulfur attended models manner spraying chemical gases on the rules of the glass temperature preparation (350c) were calculated energy gap allowed direct these membranes as observed decrease in the value of the energy gap at reducing the proportion ofsulfur ions as absorption coefficient was calculated
The electrical properties of CdO/porous Si/c-Si heterojunction prepared by deposition of CdO layer on porous silicon synthesized by electrochemical etching were studied. The structural, optical, and electrical properties of CdO (50:50) thin film prepared by rapid thermal oxidation were examined. X-ray diffraction (XRD) results confirmed formation of nanostructured silicon layer the full width half maximum (FWHM) was increased after etching. The dark J-V characteristics of the heterojunction showed strong dependence on etching current density and etching time. The ideality factor and saturation current of the heterojunction were calculated from J-V under forward bias. C-V measurements confirmed that the prepared heterojunctions are abrupt
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