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Astrophysical parameters of ten poorly studied open star clusters

Research in Astronomy and Astrophysics 2012年第1期12卷 75-83页

作者： Ashraf Latif Tadross Reda El-Bendary Anas Osman nader ismail Abdel Aziz Bakry National Research Institute of Astronomy & Geophysics Faculty of Science Al-Azhar University

We present the fundamental parameters of ten open star clusters, nominated from Kronberger et al. who presented some newly discovered stellar groups on the basis of the Two Micron All Sky Survey photometry and Digitized Sky Survey visual images. Star counts and photometric parameters （radius, membership, distance, color excess, age, luminosity function, mass function, total mass, and dynamical relaxation time） have been determined for these ten clusters for the first time. In order to calibrate our procedures, the main parameters （distance, age, and color excess） have been reestimated for another five clusters, which are also studied by Kronberger et al.

关键词： Galaxy: open clusters and associations: general-- stars: luminosity func-tion mass function -- catalogs surveys -- infrared: stars

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Tethering of Homo and Block Glycopolymer Chains onto Montmorillonite Surface by Atom Transfer Radical Polymerization

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Open Journal of Organic Polymer Materials 2012年第4期2卷 80-88页

作者： Amal Amin Heba Kandil Ahmed Ramadan Mohamed nader ismail Chemistry Department Faculty of Science Helwan University Cairo Egypt Polymers & Pigments Department National Research Center Giza Egypt

Well-defined homo glycopolymer/montmorillonite (MMT) nanocomposite (gly1) was prepared successfully by the “grafting from” technique from the modified surface of MMT via surface initiated atom transfer radical polymerization (SI-ATRP) of 3-O-methacryloyl-1,2:5,6-di-O-isopropylidene-α-D-glucofuranose (gly) in the presence of Cu(I)Br/ bi- pyridyl at 90?C in xylene. Well-defined diblock copolymers (gly2, gly3, gly4 and gly5) were also synthesized via the same technique by using comonomers of methylmethacrylate (MMA) or styrene (St) with glycomonomer (gly) using the same catalytic system. The formed nanocomposites showed both intercalated and exfoliated structures, as judged by XRD and TEM measurements. Further analyses were performed on such nanocomposites to confirm their formation such as TGA and DSC. The structures of the attached polymers to MMT were characterized by 1H NMR.

关键词： Glycopolymers Polymer/Layered Silicates Nanocomposites SI-ATRP Montmorillonite

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