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991.
WANG Ming LI Ying XIE ZhiYuan & WANG LiXiang State Key Laboratory of Polymer Physics Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun China 《中国科学B辑(英文版)》2011,(4)
A series of conjugated copolymers of 9,9-dioctylfluorene and symmetrical pyrazine unit (BY) were synthesized by Suzuki copolymerization and were used as novel light-emitting materials in PLEDs.Efficient energy transfer was observed in both thin film and solution.Compared with the lowest occupied molecular orbital (LUMO) energy level of the polyfluorenes homopolymer (PFO),the lower LUMO energy levels of copolymers indicated that the introduction of the BY unit would be benefit to electron injection.The turn-... 相似文献
992.
YUAN Kun- ZUO GuoFang LIU YanZhi ZHU YuanCheng LIU XinWen & ZHANG JunYan Key Laboratory for New Molecule Design Function of Gansu Education Department College of Life-Science Chemistry Tianshui Normal University Tianshui China State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical Physics Chinese Academy of Sciences Lanzhou China 《中国科学B辑(英文版)》2011,(1)
The optimized geometries of the three complexes between MeHn (Me=Na,Mg,Be;n=1 or 2) and SiH4 have been calculated at the B3LYP/6-311++g**,MP2/6-311++g(3df,3pd) and MP2/aug-cc-pvtz levels,respectively.The red-shift inverse hydrogen bonds (IHBs) based on Si-H,an electron donor,were reported.The calculated binding energies with basis set super-position error (BSSE) correction of the three complexes are-5.98,-8.65 and-3.96 kJ mol-1 (MP2/6-311++g(3df,3pd)),respectively,which agree with the results obtained via M... 相似文献
993.
994.
Donghai Wu Hong You Darui Jin Xuchun Li 《Journal of photochemistry and photobiology. A, Chemistry》2011,217(1):177-183
The inactivation of Escherichia coli (E. coli) in water was investigated systematically with Ag-coated TiO2 thin film under UV-C irradiation. Compared with UV-C irradiation alone, the inactivation of E. coli by the UV/Ag-TiO2 process was enhanced and the photoreactivation of the bacteria was much repressed. Moreover, atomic force microscopy (AFM) measurements of E. coli showed that the presence of Ag-TiO2 thin film during UV exposure could expedite the destruction of cell wall and cell membrane, which was further confirmed by the formation of malondialdehyde (MDA) and leakage of intracellular potassium ion (K+) and protein. The results suggest that the cell structure destruction might be the major reason for the enhancement of inactivation efficiency, and the prepared Ag-TiO2 thin films show potential as a new improvement tool for UV-C disinfection. 相似文献
995.
The effects of the amounts of starch, sodium acrylate (NaAA) and dicumyl peroxide (DCP) on the properties of chloroprene rubber (CR)/starch/NaAA composites prepared by melting method were investigated. The results showed that the addition of starch improved the mechanical properties, but decreased the water‐absorbing capacity of the composite, most likely due to the decrease in the local concentration of the main water‐absorbing material sodium polyacrylate and the increase in crosslinking density of the composite resulting from the reaction between starch and CR. This reaction was verified by the vulcanized curves, DSC curves, and the cut surface morphology. The as‐prepared composite demonstrated higher water‐absorbing capacity, resulting from the incorporation of NaAA. The mechanical properties decreased with increasing the DCP loading, and the water‐absorbing ratio is the maximum at 1.0 phr DCP. The tensile strength of the composite decreased significantly after water immersion, due to the absorbed water acting as a plasticizer. The extracted component from composites after water immersion is mainly sodium polyacrylate according to Fourier transform infrared (FT‐IR) spectroscopy analysis. The morphology of the composites before and after water immersion was observed by optical transmission microscopy (OTM). The results indicated that the starch exhibits a good dispersion state, and the water‐absorbing capacity results primarily from sodium polyacrylate. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
996.
Han‐Guang Wu Xiao‐Jie Ju Rui Xie Ying‐Mei Liu Jin‐Gen Deng Catherine Hui Niu Liang‐Yin Chu 《先进技术聚合物》2011,22(9):1389-1394
A novel ion‐imprinted strategy is developed for synthesizing responsive hydrogels with rapid response to potassium ions. With potassium ions as templates, ion‐imprinted poly(N‐isopropylacrylamide‐co‐benzo‐15‐crown‐5‐acrylamide) (P(NIPAM‐co‐B15C5Am)) hydrogels are synthesized with 15‐crown‐5 crown ethers mounted on the polymer networks in pairs; therefore, it is very easy and fast for the crown ethers to capture potassium ions again by their Venus flytrap action and form stable 2:1 “host–guest” complexes with potassium ions in the ion‐recognition process. As a result, the response rate of the ion‐imprinted hydrogels to potassium ions is significantly faster than that of normal P(NIPAM‐co‐B15C5Am) hydrogels in which 15‐crown‐5 crown ethers are randomly pendent on the polymeric networks. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
997.
Alkali metal cations easily form complexes with proteins in biological systems; understanding amino acid clusters with these cations can provide useful insight into their behaviors at the molecular level including diagnosis and therapy of related diseases. For the purpose of characterization of basic interaction between amino acids and alkali metal, each of the 20 naturally occurring amino acids were ionized in the presence of lithium, sodium and potassium cations by electrospray ionization, and the resulting product ions were analyzed. We focus our attention on the gas phase alkali metal ion-proton exchanged complexes in current study, specifically complexes with serine, threonine, asparagine and glutamine, which share characteristic pattern unlike other amino acids. All amino acids generated [M + H](+) and [M + Na](+) ions, where M stands for the neutral amino acid. Serine, threonine, asparagine and glutamine generated cluster ions of [nM - nH + (n + 1)Na](+) and [nM - (n - 1)H + (n - 1)Na + K](+) , where n = 1-7. While the (M - H + Li) and (M - H + K) species were not observed, the neutral (M - H + Na) species formed by proton-sodium cation exchange had a highly stable cyclic structure with ketone and amine ligand sites, suggesting that (M - H + Na) serves as a building block in cluster ion formation. Cluster ion intensity distributions of [nM - nH + (n + 1)Na](+) and [nM - (n - 1)H + (n - 1)Na + K](+) showed a magic number at n = 3 and 4, respectively. Extensive B3LYP-DFT quantum mechanical calculations were carried out to elucidate the geometry and energy of the cluster ions, and they provided a reasonable explanation for the stability and structure of the cluster ions. 相似文献
998.
Yuan AH Qian SY Liu WY Zhou H Song Y 《Dalton transactions (Cambridge, England : 2003)》2011,40(19):5302-5306
Reactions of the precursors [Ni(macrocyclic ligand)](2+) with [W(CN)(8)](3-) afford two octacyanotungstate-based assemblies, (H(2)L(1))(0.5)[Ni(L(1))][W(CN)(8)]·2DMF·H(2)O (L(1) = 5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane) (1) and [Ni(L(2))](3)[W(CN)(8)](2)·4H(2)O (L(2) = 3,10-dipropyl-1,3,5,8,10,12-hexaazacyclotetradecane) (2). Single crystal X-ray diffraction shows that 1 consists of anionic one-dimensional (1D) linear chains, while 2 is built of 2D graphite-like layers with (6, 3) topology. Magnetic studies reveal that both complexes exhibit metamagnetic behavior from the spin-canted antiferromagnet to the ferromagnet induced by field. 相似文献
999.
You Q Fu Y Ding Z Wu L Wang X Li Z 《Dalton transactions (Cambridge, England : 2003)》2011,40(21):5774-5780
BiSbO(4) nanoplates with a large BET specific area has been prepared successfully via a facile hydrothermal reaction from Sb(2)O(3) and Bi(NO(3))(3). The effects of reaction conditions and the precursors on the final products were investigated. It is proposed that the redox reaction between Sb(2)O(3) and Bi(NO(3))(3) plays a pivotal role in the formation of nanocrystalline BiSbO(4). The hydrothermally prepared nanocrystalline BiSbO(4) was characterized by X-ray diffraction (XRD), N(2)-sorption BET surface area, UV-vis diffuse reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The DRS result clarifies that BiSbO(4), originally believed to be a visible light responsive photocatalyst, is indeed UV light responsive with a band gap of 3.5 eV. The existence of Bi containing an impurity may be responsible for the visible light response of BiSbO(4) prepared via a conventional solid state reaction. BiSbO(4) nanoplates prepared via the hydrothermal method showed superior photocatalytic performance for the degradation of benzene and 4-chlorophenol (4-CP) as compared to BiSbO(4) prepared via a solid state reaction and Degussa P25. BiSbO(4(Hy)) nanoplates can be a promising photocatalyst in the treatment of environmental pollution. 相似文献
1000.
A new polyoxygenated ergostane-type sterol, 3β,5α,6β,8β,14α-pentahydroxy-(22E,24R)-ergost-22-en-7-one (1), has been isolated from the liquid culture of the basidiomycete Ganoderma applanatum together with four known sterols, 3β,5α,9α-trihydroxy-(22E,24R)-ergosta-7,22-dien-6-one (2), ergosterol peroxide (3), 6-dehydrocerevisterol (4) and cerevisterol (5). Two of these sterols (2, 4) are reported to have been isolated from this species for the first time. The structures of these compounds were determined by chemical and spectroscopic analyses, including 1D- and 2D-NMR, as well as by comparison of their spectroscopic data with those reported in the literature. 相似文献