Abstract Laser surface treatment of materials is one of the most effective methods of improving properties and performance of metallic articles. This technique proved its capabilities and advantages in comparison with other methods of surface treatment As an example, it has been shown that the distortion caused by this type of treament is at least one order of magnitude smaller than by that due to other techniques. Moreeover, laser beam is capable of reaching practically any point of the surface whatever it is narrow or difficult to reach by other techniques. The current work investigates the possibility of improving certain mechanical properties of both technically pure aluminum and A1-4o/oSi alloy, using ruby laser of 3 xl 05 W/cm2 power density. The surface of the investigated materials has been impregnated by SiC particles of varying size ranges, with or without firrther alloying of the surface with Titanium powder addition to the impregnated mixture. The laser treatment included coating one surface of each specimen of SiC particles by means of a binder added at a certain ratio (with or without Ti additions to the mixture). The coated surface was then subjected to the laser beam, which melted a layer I OO-150Jilll thick. Due to hydrodynamic effects the melt mixes with SiC particles and dissolves some or all of the added Ti and rapidly solidifies forming a thin layer distinct in properties from the original surface. Two groups of specimens were used in this study. The first group was treated by impregnating SiC particles of one size range with or without Ti-additions. Various numbers of laser pulses have been applied increasmg in a geometrical progression (1-2-4-8 pulses). These specimens were used for the study of the effect of varying: 1) the chemical composition of the substrate materials ;2) the number of laser pulses :and 3) the effect of Ti additions to the impregnating mixture on the microstracture and microhardness of the treated zones. The specimens of the 2nd group were coated by a square network of laser treated zones each 1.5mm in diameter. These specimens have been used to study :1) the effect of the chemical composition of the substrate material ;2) the size of the SiC particles and 3) the effect of Ti addition to the mixture on the wear perfomance of the treated specimens. Identical specimens have been used to determine the solubility of Si into the aluminum phase during the test by means of x-ray diffraction. This dissolved Si is partly responsible for the increase ID microhardness and wear resistance of the investigated specimens. The results show the positive effect of the applied treatment on the properties and preformence of technically pure AI and A-4%Si alloy. The materials microhardness within the treated zones has been increased by a factor of 2.7 and 2.4 for pure Al and Al-4%Si substrates, respectively. The microstructure of the treated zones became more homogeneous and the penetration of SiC particles into them has been increased with increasing the number of the applied laser pulses. The wear resistance of pure Al has been increased by a factor of 73.6 due to laser assisted impregnation, while that of AI-4%Si by afactor of 42.5. Wear resistance was found to increase with I) Si addition to the base metal; 2) Ti addition to the impregnated mixture, and 3) increasing the SiC particle size. This thesis is a part of a wider study that deals with surface treatment of Al and AI-Si alloys undertaken in our laboratry. Such study proved how effective the laser alloying and impregnation of such alloys in improving some of their mechanical properties which are important in industrial application, especially in internal combustion engine design.
أسماء عبد الرزاق وهرة (2002)

Due to the global concerns on the depletion of fossil fuels and the negative effect of their use in environmental pollution and climate change, renewable energy resources are increasingly in demand. Global solar power generation has almost doubled during the last 2 years with countries, such as China, leading the way with huge investments. The first generation of solar cells are either single or multi crystalline silicon, and still have 59% market share; the second (amorphous silicon, copper indium gallium selenide, and cadmium telluride) is approaching in terms of cost and efficiency; and the third (dye sensitized solar cells, organic photovoltaic, quantum dots, and perovskite) all show promise yet are still to come to market. However, future solar cells (using copper oxide and zinc oxide) featuring the regular intrusion of one junction layer into the other in order to massively improve junction contact area are of particular promise. arabic 7 English 50
Adel Diyaf, Yahya Alajlani, Abed Alaswad, Frank Placido, Des Gibson(1-2018)

تمّ في هذا البحث تصميم وبناء منظومة مسح ليزرية ثنائية الأبعاد محلياً (جامعة الفاتح/كلية العلوم/قسم الفيزياء) بدقة 0.480 mmواستُخدمت في عدة تطبيقات فيزيائية :- عملية مسح لمرآة مستوية, إيجاد معامل انكسار الزجاج, عمل مقارنة بين مقدار انعكاسية سطوح معادن مختلفة, مقارنة بين الدراسة العملية والنظرية لإنعكاسية النمط الكهربي المستعرض في الزجاج وتحقيق قانون مالوس.المكونات الرئيسية للمنظومة :- 1 – مصدر لشعاع الليزر.2- مجس ضوئي.3- دائرة استقبال وتحويل الإشارة الكهربية إلى إشارة رقمية متصلة بالحاسب الآلي.4- برنامج لعرض ورسم البيانات مباشرة على الحاسب الآلي.تمّ استخدام ليزر الهيليوم - نيون بقدرة mW 1 وبزاوية سقوط مقدارها ◦45, مجس ضوئي (الفوتوترانزستور) باستجابة للأطوال الموجية في المدى من1130 nm  400nm يتصل المجس بدائرة الكترونية لتحويل الإشارة الكهربية العادية إلى إشارة رقمية بعد أن يتم تكبيرها لتلائم التطبيق. يتحرك كلاً من مصدر الليزر والمجس الضوئي حركة آلية في اتجاه محور X كما تتحرك العينة أيضاً آلياً باتجاه محورY. دائرة الربط بالحاسب الآلي تتكون من مكبر إشارة لتكبير الإشارة الكهربية ومحول رقمي لتحويلها إلى إشارة رقمية تغذي الحاسب الآلي، يتم رسم الإشارة الناتجة وكذلك طباعة وتخزين البيانات في ملف خاص حتى تتم معالجتها لاحقاً وذلك عن طريق برنامج بلغة C. أثبتت المنظومة كفاءتها في سرعة نقل المعلومات على الأسطح دون لمس العينة المراد دراستها والتحكم فيها آلياً. Abstract In this Thesis, a two-dimensional laser scanning system was designed and constructioned accuracy was 0.480 mm. It was used in several physical applications :- a scanning of a plane mirror, determination of refractive index of glass, a comparison between reflectivity several surfaces of different metals, a comparison between practical and theoretical reflectivity of Transverse Electric Mode of glass and Malus’ Law.Main components of the system:- 1- laser beam source. 2- Light sensor. 3- Computer interface (An electronic digital circuit to convert electrical signal to digital signal). 4- A computer Software program using C – Language for data analysis. A helium - neon laser Source with output power 1 mW was used, with incidence angle of 45˚. The signal was received by a photo–transistor (response 400 nm → 1130 nm). The triangulation method was used in this system. The electrical signal from the sensor is amplified using OP amplifier and then converted to a digital signal using A/D converter. Both the Laser source and photo – transistor moves automatically in X – direction, the sample as will moves automatically in Y – direction. Computer interface consist of OP amplifier to amplify the electrical signal and a A/D converter to convert the signal to digital signal. The data was collected automatically using a – C – language program. The output data also can be plotted directly in X-Y plot on the screen. The system was very efficient and very fast data collection and transfer as a non–contact method.
نادية مسعود محمد الربع (2010)