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971.
In this work, the gold nanoparticle self-assembly behavior of mica-surface-confined polyelectrolyte/surfactant complex films was investigated. First, modified partially hydrated polyacrylamide (MHPAM)/hexadecyltrimethylammonium bromide (CTAB) complex films were deposited on the mica surface using Langmuir–Blodgett technique. Then, the preadsorbed MHPAM/CTAB complex film mica plate was dipped into the gold aqueous solution and the interesting fractal nanostructured gold network was formed. In addition, the effect of dipping time on gold nanoparticle self-assembly morphology was studied. The mechanism of formation process is briefly proposed. 相似文献
972.
[structure: see text]. A new series of dendritic two-photon absorbing chromophores containing triphenylamine moiety as a core or branching points have been synthesized through a convergent synthetic strategy. One-photon and two-photon optical properties of these molecules were characterized. In the nanosecond time domain, these molecules exhibited large two-photon absorption (TPA) cross sections up to 7.56-12.2 x 10(-44) s cm(4) at 800 nm, indicating that these molecular structures were viable candidates for various two-photon related applications. 相似文献
973.
Xuchu Ma Xuebing Li Yi Du Fen Xu Yitai Qian 《Journal of solid state chemistry》2004,177(10):3824-3829
The micro-sized Sb2O3 octahedra can be synthesized on a large scale via a simple PEG-1000 polymer-assisted hydrothermal route (PAHR) in the temperature range of 160-180 °C for 10-14 h. The structures, compositions, and morphologies of the as-synthesized products are derived from X-ray power diffraction pattern, X-ray photoelectron spectra, and field emission scanning electronic microscope. Meanwhile, the optical properties of the micro-sized Sb2O3 octahedra are studied by their photoluminescene spectroscopy and Raman spectrum. Furthermore, the possible growth mechanism of the micro-metered Sb2O3 octahedra is discussed on the basis of a series of supplementary experiments. And it has been found that PEG-1000, sodium tartrate, the reaction temperature, and the reaction time have considerable effects on the final morphology of Sb2O3, while the pH value has an influence on the formation of the Sb2O3 crystals. 相似文献
974.
Pt/Au双金属纳米粒子的制备及表征 总被引:6,自引:1,他引:6
Poly (N-vinyl-2-pyrrolidone)-protected Pt/Au bimetallic nanoparticles were obtained by reducing the mixture of HAuCl4 and H2PtCl6 with sodium borohydride. UV-vis spectra, transmission electronic microscopy and X-my diffraction reveal that the prepared bimetallic nanoparticles are of alloy structure. 相似文献
975.
Systematic synthesis and characterization of single-crystal lanthanide orthophosphate nanowires 总被引:8,自引:0,他引:8
Fang YP Xu AW Song RQ Zhang HX You LP Yu JC Liu HQ 《Journal of the American Chemical Society》2003,125(51):16025-16034
A simple hydrothermal method has been developed for the systematic synthesis of lanthanide orthophosphate crystals with different crystalline phases and morphologies. It has been shown that pure LnPO(4) compounds change structure with decreasing Ln ionic radius: i.e., the orthophosphates from Ho to Lu as well as Y exist only in the tetragonal zircon (xenotime) structure, while the orthophosphates from La to Dy exist in the hexagonal structure under hydrothermal treatment. The obtained hexagonal structured lanthanide orthophosphate LnPO(4) (Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, and Dy) products have a wirelike morphology. In contrast, tetragonal LnPO(4) (Ln = Ho, Er, Tm, Yb, Lu, Y) samples prepared under the same experimental conditions consist of nanoparticles. The obtained hexagonal LnPO(4) (Ln = La --> Tb) can convert to the monoclinic monazite structured products, and their morphologies remained the same after calcination at 900 degrees C in air (Hexagonal DyPO(4) is an exceptional case, it transformed to tetragonal DyPO(4) by calcination), while the tetragonal structure for (Ho--> Lu, Y)PO(4) remains unchanged by calcination. The resulting LnPO(4) (Ln = La --> Dy) products consist almost entirely of nanowires/nanorods with diameters of 5-120 nm and lengths ranging from several hundreds of nanometers to several micrometers. Europium doped LaPO(4) nanowires were also prepared, and their photoluminescent properties were reported. The optical absorption spectrum of CePO(4) nanowires was measured and showed some differences from that of bulk CePO(4) materials. The possible growth mechanism of lanthanide phosphate nanowires was explored in detail. X-ray diffraction, field-emission scanning electron microscopy, transmission electron microscopy, electron diffraction, infrared absorption spectra, X-ray photoelectron spectroscopy, optical absorption spectra, and photoluminescence spectra have been employed to characterize these materials. 相似文献
976.
Phase-pure and well-intergrown Cu-LTA membranes are developed through copper ions exchange of sodium ions in Na-LTA framework. For pervaporation of 90.0 wt% ethanol/10.0 wt% water mixtures, the Cu-LTA membrane shows much higher water flux than Na-LTA membranes due to the enhancement of the pore size after ions exchange. 相似文献
977.
本文利用单羧基二茂铁Fc-COOH和1,1′-二羧基二茂铁HOOC-Fc-COOH作为配体分别合成了双核铈配合物Ce2(FcCOO)6 (1)和二维层状配位聚合物Ce2(OOC-Fc-COO)3(2),测定了两种配合物的晶体结构。配合物1中的金属铈离子为九配位结构,分别与周围的羧基二茂铁上的氧原子和作为辅助配体的水分子配位,茂铁间的π-π相互作用将配合物1的二聚体单元连结在一起形成二维的网状结构。配合物2中的金属铈离子亦为九配位结构,分别与周围的羧基二茂铁上的氧原子,作为辅助配体的水分子和甲醇配位形成类似于配合物1的二聚体单元,1,1′-二羧基二茂铁HOOC-Fc-COOH作为桥基配体将二聚体单元连结在一起,形成二维网状的配位聚合物。 相似文献
978.
The mass spectral behaviour of (S,S)-2-substituted 4,4-diphenyl-3,1-oxazabicyclo[3.3.0]octanes has been studied with the aid of mass-analyzed ion kinetic energy spectrometry and accurate mass measurements under fast atom bombardment (FAB) and electron impact (EI) ionization conditions. Under FAB ionization, all compounds show a tendency to form protonated aldehyde or benzophenone ions and to form protonated 1-azabicyclo[3.1.0]hexane ions, which can further lose an ethylene or cyclopropane from the pyrrolidine ring to produce protonated 1-azabicyclo[1.1.0]butane ions and 3H-azirine ions, respectively. Under EI ionization, a similar fragmentation to that under FAB ionization was observed. The title compounds also show a tendency to yield oxirane ions and oxirenium ions by loss of pyrrolidine and pyrrolidine plus H. Ring contractions of 1,3-oxazolidine by loss of an aldehyde or ketone and of pyrrolidine by loss of an ethylene or cyclopropane were observed under both FAB and EI ionization conditions. 相似文献
979.
The mode of adsorption of bovine serum albumin (BSA) on porous polyethylene (PE) membrane was studied as a function of time and concentration, which may contribute to the surface coverage. An improved physical model for adsorption is initiated based on the results of the adsorptional and desorptional measurements, FTIR analysis, and AFM observations as well as streaming potential measurements. The results obtained indicate that the adsorptional mode depend on both time and concentration. It is shown that a critical concentration (about 1000 ppm here) exists in the adsorptional process. Below this concentration, the adsorption seems to be conducted in a normal side-on way but time elapse gives rise to greater conformational change than concentration increase; above this concentration, the aggregation of protein molecular plays a decisive role and the adsorption is in an aggregation way, which is similar to end-on, but a relative large gap between the adsorbed molecules exists due to aggregation. This conclusion is general and can be expected to apply in other globular protein-hydrophobic porous surface systems. 相似文献
980.
Bian HD Gu W Xu JY Bian F Yan SP Liao DZ Jiang ZH Cheng P 《Inorganic chemistry》2003,42(14):4265-4267
The first mu(3)-oxalato-bridged copper(II) complex, [[Cu(3)(L)(3)(mu(3)-C(2)O(4))][Cu(L)(H(2)O)](ClO(4))(2)] x 0.5(H(2)O) x 0.5(CH(3)OH), where HL = N-ethyl-N'-salicylidene-1,2-diaminoethane, has been synthesized and characterized by variable-temperature magnetic susceptibility measurement. The complex exhibits ferromagnetic coupling between the oxalato-bridged copper atoms and antiferromagnetic coupling between the oxygen-bridged copper atoms. 相似文献