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Article
Theoretical Approach to Study Assembly Nature of Molecular Modeling System of Carbon Nanotube and a Nematic Liquid Crystal

Authors: Alaa Adnan Rashad --- Nasreen Raheem Jber --- Mehdi Salih Shihab
Journal: Al-Nahrain Journal of Science مجلة النهرين للعلوم ISSN: (print)26635453,(online)26635461 Year: 2012 Volume: 15 Issue: 4 Pages: 91-97
Publisher: Al-Nahrain University جامعة النهرين

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Abstract

Theoretical study for stable geometries of a nematic liquid crystal (LC) molecule assembled on the carbon nanotubes (CNT) wall by using semi-empirical molecular quantum calculations within the PM3 method as implemented in Hyperchem package. The interaction influence of ,-stacking between N-4`-Methoxybenzylidine-4-n-butylaniline (MBBA) liquid crystal molecule on the CNT wall led to formation of the local short range orientation order by LC molecules on the surface of the CNT due to the LC-CNT binding energy (,-stacking). The binding energy of the LC molecule on the CNT wall was within the typical van der Waals interaction. This binding originated from the electrostatic energy by a significant amount of charge transfer from the LC molecule to the CNT.

تمت الدراسة النظرية لاستقرارية الشكل الفراغي لجزيئات البلورات السائلة النيماتية (الخطية) المحتشدة على جدران الكاربون النانوتيوب, باستخدام حسابات ميكانيك الكم التجربية PM3 ضمن برنامج .Hyperchem وجد ان الاحتشاد ينتج من تأثير نوع (π,π ) بين جزيئات MBBA الكاربون النانوتيوب مؤدية الى تكوين طاقة الارتباط لمواقع قصيرة المدى تترتب فيها جزيئات البلورات السائلة ترتيبآ اتجاهيآ على جدار الانبوب النانوي.ان طبيعة التآثير المولد لطاقة الارتباط بين MBBA و CNT هي قوى فاندرفال و التي تنتج من التآثير الالكتروستاتيكي المتسبب من انتقال الشحنة من البلورات السائلة الى CNT .


Article
Synthesis and Evaluation the Activity of 1, 3, 4-Thiadiazole Derivatives as Antibacterial Agent Against Common Pathogenic Bacteria

Authors: Asmaa Easa Mahmood --- Alaa Adnan Rashad --- Shaymaa Naji Daham --- Evon Akram
Journal: Al-Nahrain Journal of Science مجلة النهرين للعلوم ISSN: (print)26635453,(online)26635461 Year: 2019 Volume: 22 Issue: 1 Pages: 25-32
Publisher: Al-Nahrain University جامعة النهرين

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Abstract

Schiff base compound 5-(benzylideneamino)-1,3,4-thiadiazole-2-thiol was prepared from condensation reaction of 2-amino-5-mercapto-1,3,4-thiadiazole with benzaldehyde. Schiff bases react with Copper(ӀӀ), Ferric(ӀӀӀ), Cobalt(ӀӀ) and Zinc(ӀӀ) to form four complexes. The Schiff base complexes were identification by using FTIR and UV-VIS. The antibacterial activity of complexes (Copper(ӀӀ), Ferric(ӀӀӀ), Cobalt(ӀӀ) and Zinc(ӀӀ)) were studied against S. aureus and S . epidermidis as a model of Gram positive, E. coli, P. mirabilis, C. freundii and P. aeruginosa as a Gram negative model to determine activity of synthesized complexes, after subjected them to some tests to confirm the identity of the pathogenic bacteria. Ten antibiotics (Ampicillin and Amoxicillin) have been chosen to investigate the ability of bacterial isolates to resistant the conventional antibiotic. Imipenem have been selected to contrast its efficiency with those of the new compounds because of its high efficiency. The results exhibited higher activity of the new compounds proportional to the chosen antibiotics.

Keywords

Synthesis --- 1 --- 3 --- 4-thiadiazole --- antibiotic --- antibacterial.


Article
Morphological, Liquid Crystal and Optical Band Energy Properties of Polyphosphates

Authors: Evon Akram --- Gamal A. El-Hiti --- Dina S. Ahmed --- Alaa Adnan Rashad --- et al.
Journal: Al-Nahrain Journal of Science مجلة النهرين للعلوم ISSN: (print)26635453,(online)26635461 Year: 2019 Volume: 22 Issue: 2 Pages: 19-26
Publisher: Al-Nahrain University جامعة النهرين

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Abstract

New metallic liquid crystalline polyphosphates showed thermotropic nematic liquid crystal phases (2.13–2.24 eV). The surface morphology of polyphosphates was examined by the scanning electron microscope and showed rough surface and micro pore structure which an indication of the presence of several crystalline domains.

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