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71.
Wen-Jia Zhou Shu-Juan Bao Yan-Yu Liang Ben-Lin He Hu-Lin Li 《Journal of Solid State Electrochemistry》2006,10(5):277-282
Pure-phase and well-crystallized spinel LiMn2O4 powders were successfully synthesized by a simple rheological phase method. The thermal behavior and structure properties
of the powders prepared by the rheological phase method compared with the solid-state reaction were investigated by thermogravimetry,
powder X-ray diffraction , scanning electron microscopy and transmission electron microscopy. According to the results of
the electrochemical tests, it is obvious that the sample resulting from the rheological phase method shows higher discharge
capacity and better cycling stability than one formed in the solid-state reaction. The cyclic voltammogram and columbic efficiency
curves also confirm that the product by the rheological phase method has a good cycling performance due to its fine cubic
spinel structure and morphology. 相似文献
72.
A bio-mimic bulk acoustic wave (BAW) sensor was fabricated by coating the caffeine (CAF) template molecular imprinting polymer (MIP). This sensor exhibited high selectivity and a sensitive mass response to CAF. The response range of the sensor was between 5.0 x 10(-9) and 1.0 x 10(-4) M with a detection limit of 5.0 x 10(-9) M at pH 8.0. Recoveries were 96.1-105.6%. Influencing factors were investigated in detail and optimized. When employed to detect real samples, the proposed method proved to be a convenient method with the advantages of high sensitivity, good selectivity and ease of handling. 相似文献
73.
A microchip CE-amperometric detection (AD) system has been fabricated by integrating a two-dimensionally adjustable CE microchip and an AD cell containing a one-dimensionally adjustable disk detection electrode in a Plexiglas holder. It facilitates the precise 3-D alignment between the channel outlet and the detection electrode without a complicated 3-D manipulator. The performance of this unique system was demonstrated by separating five aromatic amines (1,4-phenyldiamine, aniline, 2-methylaniline, 4-chloroaniline, and 1-naphthylamine) of environmental concern. Factors influencing their separation and detection processes were examined and optimized. The five analytes have been well separated within 140 s in a 74 cm long separation channel at a separation voltage of +2500 V using a 10 mM phosphate buffer (pH 3.5). Highly linear response is obtained for the five analytes over the range 20-200 microM with the detection limits ranging from 0.46 to 1.44 microM, respectively. The present system demonstrated long-term stability and reproducibility with RSDs of less than 5% for the peak current (n = 9). The new approach for the microchannel-electrode alignment should find a wide range of applications in CE, flowing injection analysis, and other microfluidic analysis systems. 相似文献
74.
Bao J Baker RK Doss GA Kayser F Kotliar A Miao S Parsons WH Rupprecht KM 《Organic letters》2002,4(11):1871-1873
[reaction: see text] Pentacyclic triterpenoid natural product correolide (1) was converted to ketone 2 via ozonolysis. An unusual fragmentation reaction of ketone 2 with LiCl was discovered. This reaction is general among several similar substrates examined and appears to be specific for the correolide-type E-ring structure (ketone). A mechanism involving a retroaldol reaction, a nucleophilic opening of the epoxide, and a subsequent acetoxy elimination reaction was proposed. 相似文献
75.
Wei Lun-Cún Bao Shanglian Yang Qixiang Yang Xihong 《Journal of Radioanalytical and Nuclear Chemistry》1991,151(1):75-81
Combining the Charged Particle Activation Analysis (CPAA) and the Channeling Technique, the partial concentrations of the impurity carbon atoms in different crystal lattice locations of GaAs were claculated. The calculated results show that at lower total concentrations (0.3 ppm), carbon atoms occupy principally the octahedral and displaced octahedral interstitial positions, but at higher total concentrations (2 ppm), the substitutional carbon plays a principal role. 相似文献
76.
H. Bao S. Navaratnam B. J. Parsons G. O. Phillips 《Radiation Physics and Chemistry》1993,42(4-6):989-992
One-electron oxidation of the ferrous tris-PQ complex, a model for lipoxygenase, was attempted using oxidants such as •OH, N•3, Br•-2, Tl2+ and TlOH+. •OH was found to react with the complex with a bimolecular rate constant of (3.9±0.6)x109dm3mol-1s-1, a rate which is not very dissimilar to that for the reaction with the ligand PQ. However the product of the reaction was found to be a OH-adduct rather than a cation radical. No reaction was found to occur with N•3 or Br•-2. Both Tl2+ and TlOH+ reacted with the complex to form its oxidised species with rate constants of (7.0±1)x108dm3mol-1s-1 and (4.0±0.8)x108dm3mol-1s-1, respectively. From a comparison of the rate constants and the transient spectra it was concluded that the centre of oxidation is the ligand rather than the metal. 相似文献
77.
Qin Ren Hong Jin Zhang Xiao Kang Zhang Bao Tong Huang 《Journal of polymer science. Part A, Polymer chemistry》1993,31(4):847-851
To get hydrogenated polybutadiene-polymethyl methacrylate (HPB-b-PMMA) block copolymer to be used as a compatibilizer for blends of polyolefin/polar polymer, PB-b-PMMA was synthesized by anionic-free radical mechanism transformation polymerization. Selective extraction, gradient elution thin layer chromatography, and oil-oil emulsion separation techniques were tried to attempt to separate the copolymerization products. Hydrogenation of the PB sequence in PB-b-PMMA yielded HPB-b-PMMA. The compatibilizing function of PB-b-PMMA was shown in blending experiments. © 1993 John Wiley & Sons, Inc. 相似文献
78.
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80.
A new study of the enzymatic hydrolysis of carboxymethyl cellulose with a bulk acoustic wave sensor 总被引:4,自引:0,他引:4
A new bulk acoustic wave (BAW) cellulase sensing technique, which is based on the enzymatic hydrolysis process of sodium carboxymethylcellulose (CMC) by cellulase, was established. The frequency shift curves of BAW sensor indicated that the viscosity of the tested solutions decreased during the hydrolysis process. The hydrolysis rate of CMC by cellulase was calculated from the frequency shift curves. The hydrolysis rate of CMC under different pH conditions at 30°C showed that cellulase had high hydrolysis ability approximately at pH 5.0. Kinetic parameters (the Michaelis constant Km and the maximum rate Vmax) of the process were estimated by using a linear method of Lineweaver–Burk plot. Km is 1.95±0.25 mg ml−1 and Vmax is −(4.25±0.58)×10−3 g1/2 cm−3/2 cP1/2 min−1. Also the activation energy (Ea) of the enzymatic hydrolysis, with a value of 51.99±1.26 kJ mol−1, was estimated in this work. 相似文献