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A new water-soluble mid-chain macrophotoinitiator of polyacrylamide (PAAm) has been synthesized by redox polymerization. The polymerization of acrylamide (AAm) initiated by dihydroxy functional photoinitiator namely, 2-hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methyl propan-1-one (HE-HMPP), Irgacure 2959, in combination with cerium(IV) ammonium nitrate has been investigated in aqueous nitric acid. The effects of HE-HMPP, AAm, and Ce(IV) concentrations on the polymerization rate were investigated. The photodegradation and IR, 1H NMR, UV, and fluorescence spectroscopic studies revealed that polyacrylamide with desired photoinitiator functionality in the middle of the chain were obtained. This prepolymer was used in photoinduced free radical polymerization of methyl methacrylate (MMA) to produce PAAm-PMMA block copolymer. 相似文献
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Phase change material microcapsules were prepared by complex coacervation of silk fibroin (SF) and chitosan (CHI). n-Eicosane was used as the core material. The effects of SF/CHI ratio, and percentage of cross-linking agent and n-Eicosane content on the properties of microcapsules were studied. The size distribution and the surface morphology of microcapsules
were characterized by optical and scanning electron microscopy. The encapsulation of core material was determined by energy
dispersive spectrometer analysis. The results indicated that SF/CHI microcapsules were prepared successfully. Microcapsules
had smooth outer surface when the ratio of SF to CHI was close to 5. On the other hand, at high SF/CHI ratios (≥14), microcapsules
showed a two-layer structure, an inner compact layer, and an outer, more porous, sponge-like layer. The highest microencapsulation
efficiency was obtained at a SF/CHI ratio of 20 in the presence of 0.9% cross-linking agent and of 1.5% n-Eicosane content. 相似文献
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L.G. Dakhno A.V. Kravtsov E.A. Lobachev M.M. Makarov V.I. Medvedev G.Z. Obrant V.I. Poromov V.V. Sarantsev V.M. Sirin G.L. Sokolov S.G. Sherman 《Physics letters. [Part B]》1982,114(6):409-413
The cross section of the reaction pn → ppπ? has been measured in a deuterium bubble chamber at 9 incident energies in the range 500–1000 MeV. The energy dependence of the isoscalar cross section of single pion production is obtained. It is shown, that if an isoscalar dibaryon resonance exists with the mass in the range 2.17–2.30 GeV its elasticity should be smaller than the theoretical predictions available. 相似文献
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A.V. Kravtsov E.A. Lobachev M.M. Makarov V.I. Medvedev V.V. Nelyubin G.Z. Obrant V.I. Poromov V.V. Sarantsev S.G. Sherman V.M. Sirin G.L. Sokolov L.N. Tkach 《Nuclear Physics B》1978,134(3):413-422
The cross section for the reaction π?n→π?π?p has been measured in a deuterium bubble chamber. The cross section at Eπ,lab = 226, 250 and 312 MeV was found to be equal to 9.4 ± 2.3, 25.0 ± 5.3 and 57 ± 10 μb, respectively. 相似文献
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Manar M. Arafeh Ebrahim Saeedian Moghadam Sirin A. I. Adham Raphael Stoll Raid J. Abdel-Jalil 《Molecules (Basel, Switzerland)》2021,26(14)
A novel series of 2-(aryldiazenyl)-3-methyl-1H-benzo[g]indole derivatives (3a–f) were prepared through the cyclization of the corresponding arylamidrazones, employing polyphosphoric acid (PPA) as a cyclizing agent. All of the compounds (3a–f) were characterized using 1H NMR, 13C NMR, MS, elemental analysis, and melting point techniques. The synthesized compounds were evaluated for cytotoxic activity against diverse human cancer cell lines by the National Cancer Institute. While all of the screened compounds were found to be cytotoxic at a 10 µM concentration, two of them (2c) and (3c) were subjected to five dose screens and showed a significant cytotoxicity and selectivity. 相似文献
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Pencil graphite electrode (PGE) modified with MWCNT and Bi3+ (MWCNT/Bi/PGE) was utilized in simultaneous analysis of Pb2+, Cd2+, and Zn2+. Surface and electrochemical characteristics of MWCNT/Bi/PGE were investigated via SEM, cyclic voltammetry, electrochemical impedance spectroscopy, and FTIR measurements. Even though modification with MWCNT did not improve the electroactive surface area, it significantly decreased the charge transfer resistance. Furthermore, modification with Bi3+ significantly increased the sensitivity. Finally, MWCNT/Bi/PGE exhibited the highest sensitivity and reproducibility compared to PGE and PGE modified with only MWCNT. MWCNT/Bi/PGE provided LOD values of 0.27, 0.43, and 1.63 μg L−1, and linear ranges of 1–80, 5–80, and 10–80 μg L−1 for Pb2+, Cd2+, and Zn2+, respectively. Proposed modification method offers effective electroanalytical performance with low time consumption and cost for the analyst. 相似文献
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Sirin Sahana Chandrakanta Bandyopadhyay Siddhartha Chaudhuri 《Acta Crystallographica. Section C, Structural Chemistry》2000,56(12):1450-1451
The crystal structure of the title compound, C32H24O4, contains three fused dihydropyran rings (A, B and C); ring A is fused with a benzene ring while the other two rings, B and C, are fused with naphthalene rings. Ring A adopts a half‐chair conformation with an equatorial methoxy group, whereas ring B assumes a distorted half‐chair conformation, the A/B ring junction being trans. Ring C adopts a distorted half‐boat conformation and is nearly orthogonal to ring B. Ring C is inclined to the best plane of ring A at an angle of 112.1 (1)°. 相似文献
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Mustafa Degirmenci Edip Taskesen Sirin Hicri Hasim Yilmaz 《Journal of polymer science. Part A, Polymer chemistry》2008,46(16):5404-5413
The polymerization of acrylonitrile initiated by cerium(IV) ammonium nitrate in combination with dihydroxy functional photoinitiator namely, 2‐hydroxy‐1‐[4‐(2‐hydroxyethoxy)phenyl]‐2‐methyl propan‐1‐one (HE‐HMPP), Irgacure 2959, has been investigated in aqueous nitric acid. A novel mid‐chain macrophotoinitiator of polyacrylonitrile (PAN) was obtained. The effects of acrylamide (AAm), HE‐HMPP, Ce(IV), and HNO3 concentrations and temperature on the polymerization rate, monomer conversion, and intrinsic viscosities were investigated. The photodegradation and IR, H NMR, UV, and fluorescence spectroscopic studies revealed that PAN with desired photoinitiator functionality in the middle of the chain was obtained. The obtained PAN was used as prepolymer for photoinduced free radical polymerization of methyl methacrylate (MMA) and AAm to produce block copolymers. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 5404–5413, 2008 相似文献