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991.
Kai An Yao Na Wang Jing Yue Zhuang Zheng Biao Yang Hai Yan Ni Quan Xu Cheng Sun Shu Ping Bi 《中国化学快报》2007,18(7):857-860
In this paper, differential pulse voltammetry (DPV) was applied to study the effects of aluminum Al(Ⅲ) on the lactate dehydrogenase (LDH) activity. Michaelis–Menten constant (KmN ADH) and maximum velocity (vmax) in the enzyme promoting catalytic reaction of "pyruvate(Pyr) NADH H LDDHlactate NAD " under different conditions by monitoring DPV reduction current of NAD were reported. 相似文献
992.
Trans-3-(3-pyridyl) acrylic acid (PAA) was deposited on glassy carbon electrode (GCE) by electropolymerization in pH 7.0 phosphate buffer solution (PBS). The poly (3-(3-pyridyl) acrylic acid) (PPAA) film modified glassy carbon electrode shows an excellent electrochemical response for dopamine (DA), ascorbic acid (AA) and uric acid (UA). The cyclic voltammetry oxidation peaks for DA and AA, DA and UA, AA and UA are separated by 150 mV, 130 mV and 280 mV, respectively. This permits the simultaneous determination of AA, DA and UA. The interference of AA with the determination of DA could be eliminated because of the electrostatic interaction between DA cations and the negatively charged PPAA film at pH 7.0. The anodic peak currents of DA, AA and UA increase linearly with concentration in the range of 1-40 micromol L(-1), 10-400 micromol L(-1) and 1.6-80 micromol L(-1), respectively, with a correlation coefficient (r) always higher than 0.998. The detection limit is 0.06 micromol L(-1), 0.8 micromol L(-1) and 1.1 micromol L(-1) for DA, AA and UA, respectively. 相似文献
993.
Here we report the synthesis and electrophosphorescence of a new deep-red phosphorescent Ir(III) complex with spatially embracing and thus solubilizing arylsilyl-substituted ligands, Ir(III) tris(2-(2'-benzo[b]thienyl)-5-(4'-triphenylsilylphenyl)pyridinato-N,C3'). A poly(N-vinylcarbazole) (PVK) film doped with this Ir(III) complex exhibited excellent phase homogeneity and showed saturated red electrophosphorescence of 2.7% maximum external quantum efficiency, whose Commission Internationale de L'Eclairage coordinates were (0.69, 0.30). 相似文献
994.
Ma R Wang B Liu X An Y Li Y He Z Shi L 《Langmuir : the ACS journal of surfaces and colloids》2007,23(14):7498-7504
The pyranine-induced micellization of poly(ethylene glycol)-block-poly(4-vinylpyridine) (PEG114-b-P4VP61) in aqueous solutions and pH-triggered release of pyranine from the complex micelles were studied by dynamic and static light scattering, transmission electron microscopy, 1H NMR spectroscopy, and UV-vis spectroscopy. At pH 2, the ionized pyranine can ionically cross-link the protonated P4VP block and result in well-defined spherical complex micelles with a P4VP/pyranine core surrounded by a PEG corona. The ratio of pyranine to pyridyl units can influence the structure and the properties of the resultant complex micelles. The complex micelles are stable upon dilution and heating but are sensitive to pH changes. pH-triggered release of the incorporated pyranine from the complex micelles demonstrates that the release behavior is pH-tunable and displays good controlled-release characteristics at pH approximately 4. 相似文献
995.
Cheng X Ver Heyen A Mamdouh W Uji-i H De Schryver F Höger S De Feyter S 《Langmuir : the ACS journal of surfaces and colloids》2007,23(3):1281-1286
Shape-persistent macrocycles with interiors in the nanometer regime were prepared by the oxidative cyclization of the appropriate bisacetylene precursors under high-dilution conditions. These compounds contain polycyclic aromatic hydrocarbons in the ring backbone and are decorated with extra annular oligoalkyl or silyl side groups. Interestingly, after depositing them on different surfaces and investigating the self-assembled structures by means of scanning tunneling microscopy (STM) and atomic force microscopy (AFM), various nanostructures were observed. STM showed that these macrocycles are organized in two-dimensional (2D) layers, whereas AFM showed, in addition, the formation of 2D crystallites and one-dimensional fibrils. These results reveal the importance of the extra annular substitution of the macrocycles in creating patterned surfaces and nanoscale objects. 相似文献
996.
Facile construction of novel organolanthanide square-planar macrocycles through addition of carbodiimide to an amino group 总被引:1,自引:0,他引:1
Ma L Zhang J Cai R Chen Z Zhou X 《Dalton transactions (Cambridge, England : 2003)》2007,(25):2718-2722
The reactivity of lanthanocene derivatives containing the p-aminothiophenolate ligand towards carbodiimide was examined. Reaction of Cp2Ln(p-SC6H4NH2)(THF) with RN=C=NR in THF at room temperature gave four novel organolanthanide guanidinate complexes [Cp2Ln(p-SC6H4N(H)C(NHR)=NR)]4 (R = iPr, Ln = Yb (1a), Er (2a); R = Cy, Ln = Yb (2a), Er (2b)), formed by the addition of the C[double bond, length as m-dash]N double bonds of the carbodiimide molecule to the para-position amino group. Their unique square-planar macrocycle structures have been determined through X-ray single-crystal diffraction analysis. This result provides a potential method for the construction of organolanthanide macrocycles. 相似文献
997.
Controlled Al-doped single-crystalline silicon nitride nanowires synthesized via pyrolysis of polymer precursors 总被引:1,自引:0,他引:1
Al-doped single-crystalline Si(3)N(4) nanowires were synthesized by catalyst-assisted pyrolysis of polymeric precursors. The doping levels can be controlled by tailoring the Al concentration in the precursors. It is found that the Al concentration has a significant effect on the shape, sizes, and phase compositions of the synthesized Si(3)N(4) low-dimensional nanomaterials. The photoluminescence measurements revealed that the Al dopants have a profound effect on the emission behavior. The current study provides a simple way to realize the controlled doping in Si(3)N(4) nanomaterials, which could be useful for applications in optoelectronic nanodevices. 相似文献
998.
We prove an interpolation type inequality between , and spaces and use it to establish the local Hölder continuity of the inverse of the -Laplace operator: , for any and in a bounded set in .
999.
1000.
物理实验中温度测量的改进与应用 总被引:1,自引:0,他引:1
本分析了物理实验中玻璃温度计进行测温所存在的问题,根据半导体温度传感器工作原理设计并制作了一种新型的电子测温仪,该仪器具有精度高、响应快、读数方便以及便于二次开发等优点。 相似文献