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181.
Hyo-Jin Nam Hongdoo Kim Soon Ho Chang Seong-Gu Kang Song-Ho Byeon 《Solid State Ionics》1999,120(1-4):189-195
Insertion of aniline molecules and subsequent polymerization using FeCl3 as an oxidizing agent were examined in the layers of rutile-type HNbMoO6. Although the polyaniline/host ratio was variable depending on the amount of intercalated aniline before polymerization, the interlayer spacing was constant as 6.3 Å regardless of the ratios. Comparison of FT-IR and FT-Raman spectra for (PANI)yNbMoO6 (0.26≤y≤0.64) clearly showed that both quinoid and benzenoid forms exist in the galleries of inorganic host. IR and Raman active modes of extracted PANI from the matrix were quite similar to those of emeraldine salt. 相似文献
182.
Shiwen Yang Soon Hie Tan Hongfu Li 《International Journal of Infrared and Millimeter Waves》2000,21(2):219-230
Based on the coupled mode theory, this paper presents the study on the influence of input mode mixture in circular oversized waveguide mode converters. Three kinds of commonly used waveguide mode converters, including the waveguide mode converters with varying wall radius or small axis perturbations, and the waveguide mode converters with bent structures, are taken as the examples. The results show that the spurious input modes do not simply superimpose onto the output modes, and in some cases they may deteriorate the conversion efficiency for the main output mode. Methods for transforming such spurious input mode mixture simultaneously into the main output mode are also presented in this paper. 相似文献
183.
Soon Man Hong Seung Sang Hwang Jun Yeob Lee 《Journal of Polymer Science.Polymer Physics》2001,39(3):374-379
The effect of the curing agent content on the curing behavior and liquid‐crystalline (LC) phase of the liquid‐crystalline epoxy (LCE) resin 4,4′‐di(2,3‐epoxypropyloxy)phenyl benzoate was studied. Diaminodiphenylester (DDE) was used as a curing agent. The curing behavior was observed via differential scanning calorimetry, and the LC phase was investigated with a polarized optical microscopy. The LC phase in the LCE/DDE mixture with a high DDE content was developed during curing. The onset time was inversely proportional to the DDE content. The mesophase stability of LCE/DDE was enhanced by the addition of large amounts of DDE. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 374–379, 2001 相似文献
184.
Yong‐Hyun Jin Hong‐Jo Park Seung‐Soon Im Seung‐Yeop Kwak Soonjong Kwak 《Macromolecular rapid communications》2002,23(2):135-140
Complete exfoliation of montmorillonite during Ti‐based Ziegler‐Natta polymerization of ethylene has been successfully carried out by using montmorillonite (MMT‐OH) modified with intercalation agents containing hydroxyl groups. Hydroxyl groups in intercalation agents offer facile reactive sites for anchoring catalysts in between silicate layers. Comparison of exfoliation characteristics between MMT‐OH and non‐intercalated montmorillonite showed that the feasibility of exfoliation during ethylene polymerization was highly dependent on the catalyst fixation method. 相似文献
185.
186.
Ji‐Hoon Lee Han‐Sung Yu Woohong Kim Yeong‐Soon Gal Jun‐Hong Park Sung‐Ho Jin 《Journal of polymer science. Part A, Polymer chemistry》2000,38(23):4185-4193
A new type of processable green‐emissive polymer containing alkylsilylphenyl units was synthesized via Gilch polymerization. The resulting polymer was soluble in organic solvents and was spin‐cast to make a thin film. A light‐emitting diode was fabricated by the polymer being sandwiched between indium tin oxide and metal electrodes. A strong green emission at 524 nm was observed from the various device configurations made by the newly synthesized polymer. The polymer had a strong absorption band around 427 nm that was attributable to a π–π* transition of the conjugated segments of the polymer. A current–voltage–luminance curve showed typical rectifying diode characteristics. The polymer had a very high molecular weight (number‐average molecular weight = ∼300,000) with a polydispersity of about 3 and good thermal stability up to 400 °C. The brightness at 13 and 17 V was about 1000 and 5900 cd/m2, respectively. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4185–4193, 2000 相似文献
187.
The choice of solvent is quite important to obtain good protecting surface film on graphite negative electrodes in rechargeable lithium batteries. A subtle difference of the molecular structure of solvent greatly affects the easiness of surface film formation. In order to understand the solvent effects and to elucidate the mechanism of surface film formation, morphology changes of the basal plane of highly oriented pyrolytic graphite were studied using electrochemical scanning tunneling microscopy (EC‐STM). In this article, our recent results of EC‐STM observation in different solvent systems are reviewed. 相似文献
188.
Poly(methacrylic acid) was grafted on a nanoporous polycarbonate membrane using the glow-discharge method. Atomic force microscopy showed that the pore size is dependent upon pH in such a way that a low pH the graft chains are protonated and contracted to open the pore, whereas at high pH, the graft chains became extended, thus reducing the pore size. Water permeation through the graft membrane is regulated by the pH value. The permeation rate is low at high pH value and high at low pH. This phenomenon corresponds to the pore size. 相似文献
189.
190.
Junghun Suh Hyung Soon Park 《Journal of polymer science. Part A, Polymer chemistry》1997,35(7):1197-1210
Three molecules of 5-(bromoacetyl) salicylate ( 1 ) complexed to Fe(III) ion were crosslinked with poly(ethylenimine) (PEI) in DMSO by alkylation of amino groups of PEI with 1 , leading to the formation of Fe(Sal)3PEI, a water-soluble polymer. Several other derivatives including the immobilized form were also prepared. Examination of the values of log Kf for the PEI derivatives indicated that each Fe(III) binding site in Fe(Sal)3PEI contains three salicylate moieties. In addition, the log Kf revealed that the effective molarity (EM) of the salicylate groups contained in the Fe(III) binding site is ca. 1000M. The high EM value shows that the geometry of the coordination sphere is well conserved during the crosslinkage with PEI of 1 preassembled around Fe(III) ion. In view of the EM value and the pKa values of salicylic phenols in apo(Sal)3-PEI, the metal-free form, the three salicylate groups of each Fe(III) binding site appear to occupy proximal positions leading to effective cooperation in Fe(III) binding. Fast, strong, and selective binding of Fe(III) ion by the binding site comprising three salicylate moieties was demonstrated. In addition, rapid demetalation of the resulting complexes as well as chemical stability of the immobilized chelating agents built on PEI were achieved. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1197–1210, 1997 相似文献