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101.
Hu Chuanjiang Duan Chunying Meng Qingjin Liu Yongjiang Lu Changsheng Reng Xiaoming Chen Yijun Cao Mi 《Transition Metal Chemistry》2000,25(2):141-144
The mixed-valence molybdovanadate compound Na2(NH4)4[VIVVV
8Mo)O28] · 10H2O [Vanadata(6-)tetradeca--oxotetra-3-oxodi-6-oxoheptaoxo(oxomolybdate) nonatetrammonium disodium, decahydrate] has been synthesized from sodium molybdate(VI) dihydrate and sodium metavanadate dihydrate in aqueous solution by adding NH2OH · HCl. The molecular structure has been determined by X-ray diffraction and is based on the isopolydecavanadate structure. The molybdate atom is crystallographically disordered over 6MO6 octahedral sites. The e.s.r. spectrum clearly indicates that one vanadium atom has the oxidation number +4. 相似文献
102.
Amphiphilic fluorescent graft copolymer (PVP‐PyATAm) was successfully synthesized by the free radical copolymerizations of hydrophobic monomer N‐acryloyl‐thioureylene‐4‐(1‐pyrene)‐butyryl amide (PyATAm) with hydrophilic precursor polymers of vinyl‐functionalized poly (N‐vinylpyrrolidone) (Acryloyl‐PVP) in DMF. FT‐IR, 1H NMR, TEM, gel permeation chromatography‐multi‐angle laser light scattering, UV‐vis spectroscopy, viscometric measurement, and fluorescence spectroscopy were used to characterize this copolymer. The TEM observation showed that the copolymer PVP‐ PyATAm formed spherical micelles in an aqueous solution and the size of micelles was between 50 and 70 nm in diameter. The interaction of PVP‐PyATAm copolymer and plasmid DNA was examined by agarose gel electrophoresis and TEM. Results indicated that the copolymer–DNA complexes were self‐assembled and the size of complexes was between 90 and 120 nm in diameter. Cytotoxity studies using MTT colorimetric assays suggested good biocompatibility of PVP‐PyATAm in vitro. These results suggested the potential of this graft copolymer as gene delivery carrier. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
103.
Ya-Guang Chen Fan-Xia Meng Hai-Jun Pang Dong-Mei Shi Yu Sun 《Journal of Cluster Science》2007,18(2):396-405
A novel uranyl complex with dimeric lacunary polyoxoanion like open-mouthed clam, Na5[(A-α-SiW9O33H3)2K{UO2(H2O)}2], was prepared and characterized by elemental analysis, infrared and ultraviolet–visible spectroscopy and single crystal
X-ray diffraction. In the anion, two A-α-SiW9O3410− groups share two terminal oxygen atoms Od′ derived from removal of three corner-shared W atoms from saturated α-Keggin anion, forming a dimeric anion with an open
mouth in which potassium ion and uranyl ions are coordinated. Uranium atom adopts a pentagonal bipyramidal geometry. The coordinating
anions are linked by sodium ions via coordination of terminal or bridging oxygen atoms, forming two-dimensional layer arrangement.
Between the layers are the hydrogen bonds from which a supramolecular architecture is created. UV–VIS spectrum gives W–O and
U–O charge transfer transitions at 230–265 and 432 nm, showing the change of geometry of the polyanion and weakening of the
U–O bonds of the uranyl cation.
Electronic supplementary material The online version of this article () contains supplementary material, which is available to authorized users. 相似文献
104.
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106.
纳米尺寸团簇NinZrn(n=3~5)的几何结构与成键规律研究 总被引:3,自引:0,他引:3
根据化学键理论与拓扑原理,设计了团簇NinZrn(n=3-5)的可能几何构型,并用从头算方法进行构型优化,结果表明,由NiZr组成的团簇原子间的Zr-Zr和Zr-Ni键明显较强,而Ni-Ni的成键较弱,并发与NinZrn(n=3-5)团簇电子性质与有机烯烃分子等瓣相似,原子之间的成键按照强弱相间的规则分布。 相似文献
107.
Ti基IrO2+Ta2O5阳极在H2SO4溶液中的电解时效行为 总被引:5,自引:0,他引:5
研究了450 ℃制备所得Ti/70%IrO2 30%Ta2O5(摩尔分数)高寿命阳极在H2SO4溶液电解过程中电极的物理、化学及电化学性能的时效行为.结果发现,整个电解过程可分为“活化”、“稳定”及“失效”三个阶段.在“活化”及“稳定”区内主要发生电极表面活性氧化物的溶解,涂层中IrO2金红石相的(110)、(101)晶面择优取向随电解时间延长而减弱,而(002)晶面择优增强.但是在“失效区”内,各晶面的择优程度却不随电解时间的变化而变化,这表明在“失效区”内氧化物的损失机制发生了变化.电化学阻抗谱测试表明,电极的析氧电化学反应电阻随电解时间的延长发生缓慢而连续的上升,而整个电极的物理阻抗在“失效区”内却发生突升现象.X射线衍射分析(XRD)表明,随电解时间的延长TiO2金红石相的衍射强度增大,达“失效区”时衍射强度发生突升.根据实验现象特别是“失效区”内阳极的时效行为提出高寿命Ti基氧化物涂层阳极的失效机制. 相似文献
108.
Photocycloadditionof(4-methyl-7-coumarinyl)OxyaceticAcidPropanediolDiesterandX-rayCrystalStructureofProductDuDa-Ming;WangYong... 相似文献
109.
Preparation of poly(propylene carbonate)/organo-vermiculite nanocomposites via direct melt intercalation 总被引:2,自引:0,他引:2
Intercalated nanocomposites comprised of poly(propylene carbonate) (PPC) and organo-vermiculite (OVMT) was first prepared via direct melt compounding of the alkali-vermiculite intercalated host with PPC in a twin rotary mixer. The dispersion and morphologies of OVMT within PPC were investigated by X-ray diffraction and transmission electron microscopic techniques. The results revealed the formation of intercalated-exfoliated vermiculite sheets in the PPC matrix. Because of the thermally sensitive nature of PPC, thermal degradation occurred during the melt compounding. The degradation led to a deterioration of the mechanical properties of the nanocomposites. Tensile test showed that the yield strength and modulus of the nanocomposites decrease with increasing vermiculite content. The degradation mechanism was discussed according to the results of GPC and TGA measurements. 相似文献
110.
Yong Hong Wang Ting Fang Tian Xing Qin Liu Guang Yao Meng 《Journal of membrane science》2006,280(1-2):261-269
The high-quality tubular titania MF membranes are successfully prepared by dip-coating techniques and systematically investigated with regard to their corrosive resistances. The experiments show that dispersants PAA and anatase powder were preferably employed to prepare desired suspensions with solid loading 10–15 wt.% and that suspensions properties significantly affect the final membranes quality. The titania MF membranes with pure water permeability 742.42 l m−2 h−1 bar−1 and 0.1 μm pore diameter have been obtained using the prepared suspensions. The corrosion resistance of titania membranes exhibits that the anatase layers are more stable than the alumina supports in boiling corrosive medium and that the poor quality titania MF membranes become more deteriorated due to its top layer pore blockages and fouling layer formation, which provides a wide range of practical application fields in very hash environments with reliable data supports. 相似文献