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991.
Sk. Asrof Ali Mohammad A. J. Mazumder Hasan A. Al‐Muallem 《Journal of polymer science. Part A, Polymer chemistry》2003,41(1):172-184
The reaction of diallyl amine with 1,3‐propane sultone led to the synthesis of the zwitterionic monomer 3‐(N,N‐diallylammonio)propanesulfonate. The sulfobetaine was cyclopolymerized in water in the presence of sodium chloride with t‐butylhydroperoxide as an initiator to afford a polysulfobetaine (PSB) in very good yield. PSB, upon treatment with sodium hydroxide, was converted into an anionic polyelectrolyte (APE). Although APE was readily soluble in salt‐free water, PSB needed the presence of low‐molecular‐weight salts (e.g., NaCl, KI, etc., in the range of 0.135–1.04 N) for its dissolution. The solution properties of PSB and APE were investigated with potentiometric and viscometric techniques. The basicity constant of the amine was apparent and followed the modified Henderson–Hasselbalch equation; as the degree of protonation (α) of the whole macromolecule increases, the protonation of the amine nitrogens becomes increasingly more difficult. The composition and phase diagram of the aqueous two‐phase systems of APE/PSB and poly(ethylene glycol) were also explored. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 172–184, 2003 相似文献
992.
Eqab M. Rabei Eyad H. Hasan Humam B. Ghassib 《International Journal of Theoretical Physics》2004,43(4):1073-1096
A new approach is examined in this paper for solving mechanical problems for both constrained and unconstrained systems with second-order Lagrangians, using the Hamilton–Jacobi formulation. The relevant Hamilton–Jacobi function is constructed first. This is then used to determine the solutions of the equations of motion for both systems. 相似文献
993.
Momentum dependent charge excitation of 2D cuprate class La2−xSrxCuO4 with different hole-doping levels (x) is measured using high resolution resonant inelastic X-ray scattering. Although a low-energy continuum is built up with doping, a remnant excitation gap behavior continues to exist even in highly doped metallic phase which we have studied in some detail. The excitation of the Mott gap becomes less dispersive with the increase of doping level and suggests a many-body coupling between charge fluctuation and magnetic character of the lattice. The results can be described within the framework of t-t′-t″-U model. 相似文献
994.
A simple and efficient synthesis of 2,4,6-triarylpyridines is described from a novel reaction between chalcones and ammonium acetate under solvent-free conditions in excellent yields. 相似文献
995.
996.
Salah D. M. Hasan Walderez Gambale Ricardo L. Zollner Maria H. A. Santana 《Applied biochemistry and biotechnology》2003,106(1-3):403-412
Allergenic extracts were produced from Drechslera (Helminthosporium) monoceras biomass cultured by solid-state fermentation using wheat bran as the substrate. The main fermentation variables were selected
by statistical design, and the optimized biomass yield (1.43 mg/[g of dry substrate · d]) was obtained at pH 9.5 and 45.8%
moisture. The allergenic extracts were produced from crude extract by protein precipitation and polyphenol removal. Proteins
in the range of 16–160 kDa were identified in the extracts. Their reactions in patients were characterized by in vivo cutaneous
tests (positive in 40% of the atopic patients) and by dot-blotting assays. 相似文献
997.
Tariq Mahmood Babar Muhammad Moazzam Naseer Muhammad Khawar Rauf Humayun Pervez Masahiro Ebihara Nasim Hasan Rama 《中国化学快报》2014,25(9):1282-1286
A novel fused isocoumarin skeleton has been synthesized through selective domino multicyclizations by mixing homothallic acid and 2,3-diphenylacryloyl chloride at 200℃ under catalyst and solvent free reaction conditions. Six fused rings with two stereogenic centers were assembled in a convenient onepot operation in good yield. The resulting hexacyclic fused isocoumarin skeleton and its stereochemistry was fully characterized and unambiguously confirmed by X-ray diffraction analysis. 相似文献
998.
Direct‐methanol Fuel Cell Based on Functionalized Graphene Oxide with Mono‐metallic and Bi‐metallic Nanoparticles: Electrochemical Performances of Nanomaterials for Methanol Oxidation 下载免费PDF全文
Mehmet Lütfi Yola Tanju Eren Necip Atar Hasan Saral İsmail Ermiş 《Electroanalysis》2016,28(3):570-579
The catalysts based on 2‐aminoethanethiol functionalized graphene oxide (AETGO) with several mono‐metallic and bi‐metallic nanoparticles such as rod gold (rAuNPs), rod silver (rAgNPs), rod gold‐platinum (rAu‐Pt NPs) and rod silver‐platinum (rAg‐Pt NPs) were synthesized. The successful synthesis of nanomaterials was confirmed by various methods. The effective surface area (ESA) of the rAu‐Pt NPs/AETGO is 1.44, 1.64 and 2.40 times higher than those of rAg‐Pt NPs/AETGO, rAuNPs/AETGO and rAgNPs/AETGO, respectively, under the same amount of Pt. The rAu‐Pt NPs/AETGO exhibited a higher peak current for methanol oxidation than those of comparable rAg‐Pt NPs/AETGO under the same amount of Pt loading. 相似文献
999.
Ülkü Yılmaz Hasan Küçükbay 《Phosphorus, sulfur, and silicon and the related elements》2016,191(1):140-143
Novel heterocyclic phosphoramidates were synthesized by a nucleophilic substitution reaction of 2-substitutedbenzimidazoles and diphenyl chlorophosphate (ClPO3Ph2) in the presence of potassium hydroxide (KOH) under an argon atmosphere. The structures of the phosphoramidates were characterized by NMR, IR, melting point, and elemental analysis. 相似文献
1000.
Tungsten‐loaded SMP foam nanocomposites with inherent radiopacity and tunable thermo‐mechanical properties 下载免费PDF全文
Sayyeda M. Hasan Garrett Harmon Fang Zhou Jeffery E. Raymond Tiffany P. Gustafson Thomas S. Wilson Duncan J. Maitland 《先进技术聚合物》2016,27(2):195-203
Shape memory polymer (SMP) foams have been developed for use in neurovascular occlusion applications. These materials are predominantly polyurethanes that are known for their biocompatibility and tunable properties. However, these polymers inherently lack X‐ray visibility, which is a significant challenge for their use as implantable materials. Herein, low density, highly porous shape memory polyurethane foams were developed with tungsten nanoparticles dispersed into the foam matrix, at increasing concentrations, to serve as a radiopaque agent. Utilizing X‐ray fluoroscopy sufficient visibility of the foams at small geometries was observed. Thermal characterization of the foams indicated altered thermal response and delayed foam actuation with increasing nanoparticle loading (because of restricted network mobility). Mechanical testing indicated decreased toughness and strength for higher loading because of disruption of the SMP matrix. Overall, filler addition imparted x‐ray visibility to the SMP foams and allowed for tuned control of the transition temperature and actuation kinetics for the material. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献