A random laser is a non-conventional laser whose feedback mechanism is based on dissorder-induced light. However, random lasers occur in gain media with numerous scatterers and produce coherent laser emission without any predesigned cavity. The generation of coherent emission from multiple scattering is quite general and its basic principles are shown here using sulforhodamine B-TiO suspensions system. These suspensions were pumped with 337.1 nm pulses from N2 laser and the spectral and temporal behavior of light emitted from the pumped surface was recorded. When we pump power above a certain threshold a dramatic narrowing of the emission line width and a shortening of the emitted pulses were observed. We have experimentally found that in a random laser based scattering, the threshold pumping density decreases with pump energy increased.
لقد مثلت عملية التحول من النظام الشمولي الى مشروع اقامة نظام جديد ومغاير نقلة نوعية شهده المجتمع العراقي بعد 9/4/ 2003 القت بظلالها على مختلف الاصعدة السياسية والاقتصادية والاجتماعية، ولعل من بين ابرز تلك التحولات ذلك الذي تبلور على حول مفهوم الهوية الوطنية واعادة تشكيلها من خلال صياغة جديدة لمفهوم المواطنة الذي يفترض ان تكون القاعدة الراسخة التي يتأسس عليها المشروع الوطني الجديد الرامي الى إقامة او إعادة تأسي
... Show MoreSharif al-Murtada was a historical figure, He is the author of many works in which scientific material is important for scientific studies and research, Because of the importance of his writings and his age, and the impact he left in the intellectual movement was one of the stars of Islamic civilization .
This study reveals important aspects of Ibn Tulun approach in this book through reading and scrutinizing the texts that had a direct or indirect relationship with this topic, as his study was not an easy thing, especially as it depends on the deduction of intellectual trends in his approach and his dealings with the texts of this topic In his directions and his architectural and service idea and highlighting its basic aspects as part of the plans of the Islamic city and its connection with the cultural heritage at the time.
In mid 3rd century H . and exactly in the second Abbasid era, Thereappeared ideological trends which are skeptical of Islamic religion depending upon the magic at one time , and Telmudi ideas at other times . The Muslim scholars , headed by Imam Al – Hasan Al – Askari , answerd them by Iogic and scientific arguments , relying on the gloroious Qur an and the prophetic Sunnah ,and what He learnt from his grandparents . Therefore , He managed to take down their ideas in the bud and rescue the Islamic religion from anything irrelevant to what the prophet brought .
The impact of cartoon concepts strategy in the Achievement of the first grade student's average in geography and visual thinking
The study aimed to measure the impact of cartoon concepts strategy to Achievement, visual thinking in the first grade students in the average geographical material.
Find sample consisted of 52 students were divided into two groups, the first experimental studied strategy cartoon concepts and the control group was studied in the traditional manner of parity between the two variables (chronological age, the overall rate, prior knowledge, the degree of intelligence, visual) thinking.
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Addresses research philosophy decade in significance vehicle metamorphic between the time the real is between two moments two different: the moment the last beautiful memories of parents and beloved, but the present moment harsh stand on