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941.
942.
Geng Fei Junhwa Shin Sung‐A Kang Beom‐Seok Ko Phil‐Hyun Kang Youn‐Sik Lee Young Chang Nho 《Journal of polymer science. Part A, Polymer chemistry》2010,48(3):563-569
In this study, a novel polymer electrolyte membrane, poly(vinylbenzyl sulfonic acid)‐grafted poly(tetrafluoroethylene‐co‐hexafluoropropylene) (FEP‐g‐PVBSA), has been successfully prepared by simultaneous irradiation grafting of vinylbenzyl chloride (VBC) monomer onto a FEP film and taking subsequent chemical modification steps to modify the benzyl chloride moiety to the benzyl sulfonic acid moiety. The chemical reactions for the sulfonation were carried out via the formation of thiouronium salt with thiourea, base‐catalyzed hydrolysis for the formation of thiol, and oxidation with hydrogen peroxide. Each chemical conversion process was confirmed by FTIR, elemental analysis, and SEM‐EDX. A chemical stability study performed with Fenton's reagent (3% H2O2 solution containing 4 ppm of Fe2+) at 70 °C revealed that FEP‐g‐PVBSA has a higher chemical stability than the poly(styrene sulfonic acid)‐grafted membranes (FEP‐g‐PSSA). © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 563–569, 2010 相似文献
943.
Min‐Jung Lee Moon Seong Kang Min‐Ki Shin Jong‐Won Park Dae Sung Chung Chan Eun Park Soon‐Ki Kwon Yun‐Hi Kim 《Journal of polymer science. Part A, Polymer chemistry》2010,48(18):3942-3949
New amorphous semiconducting copolymers, poly(9,9‐dialkylfluorene)‐alt‐(3‐dodecylthienyl‐divinylbenzene‐3‐dodecylthienyl) derivatives (PEFTVB and POFTVB), were designed, synthesized, and characterized. The structure of copolymers was confirmed by H NMR, IR, and elemental analysis. The copolymers showed very good solubility in organic solvents and high thermal stability with high Tg of 178–185 °C. The weight average molecular weight was found to be 107,900 with polydispersity of 3.14 for PEFTVB and 76,700 with that of 3.31 for POFTVB. UV–vis absorption studies showed the maximum absorption at 428 nm (in solution) and 435 nm (in film) for PEFTVB and at 430 nm (in solution) and 436 nm (in film) for POFTVB. Photoluminescence studies showed the emission at 498 nm (in solution) and 557 nm (in film) for PEFTVB and at 498 nm (in solution) and 536 nm (in film) for POFTVB. The solution‐processed thin‐film transistors showed the carrier mobility of 2 × 10?4 cm2 V?1 s?1 for PEFTVB‐based devices and 2 × 10?5 cm2 V?1 s?1 for POFTVB‐based devices. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3942–3949, 2010 相似文献
944.
945.
The allocation of cost savings is very important for the success of the joint relationship between the buyer and vendor in supply chain management. This paper develops integrated models with permissible delay in payments for determining the optimal replenishment time interval and replenishment frequency. In addition, the variant pricing strategy is employed to obtain both sides’ cost savings in order to entice buyers to join long-term cooperative relationships. A simple solution algorithm is presented to allocate the cost savings in the integration model, and a numerical example is used to demonstrate the feasibility of the proposed integration models. 相似文献
946.
Wen‐Fu Chang Yuh‐Sheng Wen Ling‐Kang Liu 《Acta Crystallographica. Section C, Structural Chemistry》2004,60(9):o665-o667
The title compound, C20H12N8, (I), has been prepared by the reaction of 1,4‐dihydrazinophthalazine and pyridine‐2‐carboxaldehyde, followed by an oxidative cyclization by treatment with bromine. In the solid state, the molecules of (I) are discrete, comprising a fused and twisted four‐ring system with an overall helical appearance. The distance between the two intramolecular pyridyl N atoms is 3.075 (2) Å, this short contact distance suggesting a π–π interaction. 相似文献
947.
948.
In our early researches, lanthanum and cerium could enter plant and bind to porphyrin of chlorophyll to form Ln3+-chllorophyll. La and Ce greatly increase photosystem II (PSII) activity and PSII electron transport rate, and the fluorescence emission peaks of PSII are blue-shifted [1—4]. Do REEs coordinate with PSII reaction center complex in vivo? Moreover, do REEs coordinate with D1(30 kD)/D2(32 kD)/Cytb559 (~9 kD) reaction center complex of site of producing pri-mary reaction-p… 相似文献
949.
Biao ZhouYawen Zhang Chunsheng LiaoChunhua Yan Liangyao ChenSongyou Wang 《Solid State Communications》2003,126(10):593-596
Nanocrystalline CoFe2−xScxO4 (x=0-0.4) thin films were prepared on silicon substrates at reduced temperature by a sol-gel process, and the doping effects of scandium on the microstructure, magnetism and polar magneto-optical Kerr effects of the as-deposited films were examined. It was shown that the intensities of both of the Kerr rotation peaks increase with the doping content x of Sc3+. The increase for the peak at 540 nm is due to the decrease of the electrostatic polarization of O2− resulting from the relatively large radius of Sc3+, and that for the peak at 620 nm was a result of the migration of Co2+ from octahedral to tetrahedral sites in the presence of the dopant of Sc3+. 相似文献
950.