The CdSe pure films and doping with Cu (0.5, 1.5, 2.5, 4.0wt%) of thickness 0.9μm have been prepared by thermal evaporation technique on glass substrate. Annealing for all the prepared films have been achieved at 523K in vacuum to get good properties of the films. The effect of Cu concentration on some of the electrical properties such as D.C conductivity and Hall effect has been studied.
It has been found that the increase in Cu concentration caused increase in d.c conductivity for pure CdSe 3.75×10-4(Ω.cm)-1 at room temperatures to maximum value of 0.769(Ω.cm)-1 for 4wt%Cu.All films have shown two activation energies, where these value decreases with increasing doping ratio. The maximum value of activation energy was (0.319)eV for pure CdSe film in thermal range (293-363)K. Hall effect results has shown that the sample of pure CdSe film were n-type, while it is p-type for doping films. Also the charge carrier concentration decreases with increasing Cu concentration, and it varies between 2.1×1017 cm-3 for pure films, and 5×1016cm-3 for doping films with 4wt%Cu. The Hall mobility at laboratory temperature has been calculated, and it is increased exponentially from 0.012cm2/V.sec for the pure film to 88.435 cm2/V.sec for doped films with 4wt%Cu. The drift velocity of these films increases with increasing doping concentration.
Field experiment was conducted to test the effect of saline water and fertilizers rate on Pisum sativum L. plants . Treatments of the experiment included two levels of water salinity (2, 7 dSm-1) as a main plot and three levels of potash fertilization K2SO4 (44%K) namely 150 control, 300 and 450 kg/Donum as a sub plot. Results indicated that irrigation of plant with saline water 7 dSm-¹ caused a significant decrease in K and P contents specially in the upper parts of the plants , the percentage of the K increased (2.80%) under 2 dSm-¹of irrigation water and 300 kg/ donum fertilizer rate in the upper leaves, However K decreased(1.10%) in lower leaves under 7 dSm-¹ and 300 kg/donum fertilizer. while P increased in pods und
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Acting on the Holy Qur’an by contemplating its meanings, stopping at its commands and prohibitions, and everything in it that guides us to truth and mercy. The Holy Qur’an includes it for various purposes in one verse, and there is no doubt that this is part of the perfection of this great book, and one of the sciences of the fundamentalists is the indication of the context, and it is a great science of high rank, and it is one of the most important things that lead to the correct understanding of the miraculous and decisive book of God Almighty, and one of the best meanings of the Qur’an It was not from the context of the verses, and from here it can be said that the indication of the context is one of the origins of deriving lega
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کشورعراق مرزهای زمینی ایران دارد که علاوه بر این ، مشترکات وروابط متعدد اقتصادی ،سیاسی، فرهنگی ودينى ميان هر دو ملت می باشند . عراق بعلت موقعیت جغرافیایی ونزدیکی به ایران سهم بیشتری برای ورود واژه های فارسی به لهجه ی خود داشت ، علاوه بر این رویدادهای سیاسی متقابل قدیم و جدید میان دو کشور سبب ورود بسیاری از لغات فارسی به لهجه ی عراقی شد که کاربرد این لغات هم اکنون در لهجه ی عراقی آشکار است ، ای
... Show MoreIn this work, yttrium oxide particles (powder) reinforced AL-Si matrix composites (Y2O3/Al-Si) and Chromium oxide particles reinforced AL-Si matrix composites (Cr2O3/AL-Si) were prepared by direct squeeze casting. The volume percentages of yttrium oxide used are (4, 8.1, 12.1, 16.1 vol %) and the volume percentages of the chromium oxide particles used are (3.1, 6.3, 9.4, 12.5 vol. %). The parameters affecting the preparation of Y2O3/Al-Si and Cr2O3/AL-Si composites by direct squeeze casting process were studied. The molten Al-Si alloy with yttrium oxide particles or with chromium oxide particles was stirred again using an electrical stirrer at speed 500 rpm and the molten alloy was poured into the squeeze die cavity. Th
... Show MoreThis thesis aims to study the effect of addition polymer materials on mechanical properties of self-compacting concrete, and also to assess the influence of petroleum products (kerosene and gas oil) on mechanical properties of polymer modified self-compacting concrete (PMSCC) after different exposure periods of (30 ,60 ,90 ,and 180 days).
Two type of curing are used; 28 days in water for SCC and 2 days in water followed 26 days in air for PMSCC.
The test results show that the PMSCC (15% P/C ratio) which is exposed to oil products recorded a lower deterioration in compressive strength's values than reference concrete. The percentages of reduction in compressive strength values of PMSCC (15% P/C ratio) was
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The use of blended cement in concrete provides economic, energy savings, and ecological benefits, and also provides. Improvement in the properties of materials incorporating blended cements. The major aim of this investigation is to develop blended cement technology using grinded local rocks . The research includes information on constituent materials, manufacturing processes and performance characteristics of blended cements made with replacement (10 and 20) % of grinded local rocks (limestone, quartzite and porcelinite) from cement.
The main conclusion of this study was that all ty
... Show MoreIn this study three inorganic nano additives, namely; CaCO3, Al2O3 and SiO2 were used to prepare nanocomposites of unsaturated polyester in order to modify their mechanical properties, i.e. tensile strength, elongation, impact and hardness. The results indicated that all the three additives were effective to improve the mechanical properties up to 4% by weight. The effectiveness of them follows the order : CaCO3 > Al2O3 > SiO2 This is due to their particle size in which CaCO3 (13nm), Al2O3 (20-30nm) and SiO2 (15-20nm).