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641.
《Nuclear Physics B》1998,524(3):695-741
We discuss the construction of the physical configuration space for Yang-Mills quantum mechanics and Yang-Mills theory on a cylinder. We explicitly eliminate the redundant degrees of freedom by either fixing a gauge or introducing gauge invariant variables. Both methods are shown to be equivalent if the Gribov problem is treated properly and the necessary boundary identifications on the Gribov horizon are performed. In addition, we analyze the significance of non-generic configurations and clarify the relation between the Gribov problem and coordinate singularities. 相似文献
642.
《Surface science》1988,202(3):L568-L576
We present the first study of the effect of an alkali metal overlayer on the adsorption of an organic molecule, methylchloride, on a Si(100)2 × 1 surface. In strong contrast to the behavior of molecular oxygen or nitrogen which were found to react with the silicon substrate, there was no significant interaction between methylchloride and silicon, rather, the formation of alkali-chlorine bonds was observed. Core level and valence band spectroscopies using synchrotron radiation were used to study these systems. Sodium was found to exhibit the strongest interaction with mehtylchloride which was dissociated, while the effects produced by K and Cs were weaker. 相似文献
643.
《Journal of Physics and Chemistry of Solids》2003,64(3):455-458
Poly(vinyl pyrrolidone) (PVP)-capped CdS nanoparticles were prepared with CS2 as the sulfur source through the hydrothermal process. The obtained nanoparticles were characterized by X-ray diffraction, transmission electron microscopic, ultraviolet–visible and fluorescence spectroscopy. The capped CdS nanoparticles showed remarkable stability and significantly enhanced luminescence property compared with that of the noncapped ones. We attributed this observation to the surface passivation of the CdS nanoparticles by the PVP molecules. 相似文献
644.
《Electrochemistry communications》2003,5(5):388-391
A stereoselective solid surface has been created by the self-assembly of a chiral osmium complex, λ-[Os(phen)3](ClO4)2 (phen=1,10-phenanthroline), onto a single layered clay film deposited on an indium tin oxide (ITO) electrode; the OsII–OsIII redox couple mediates the electrochemical oxidation of chiral 1,1′-2-binaphthol in a stereoselective way or the S-isomer is oxidized at 1.4 times higher rate than the R-isomer. 相似文献
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648.
A novel complex material was fabricated by three steps. In the first step, gold nanoparticle (Aunano) was prepared with the method of chemistry and dialysis. In the second step, 4‐aminothiophenol (AT) was encapsulated in the cavity of β‐cyclodextrin and formed inclusion complex, cyclodextrin/4‐aminothiophenol (CD/AT). And then inclusion complex was adsorbed to the surface of Aunano based on the bond of Au‐S interaction. In the last step, a complex material, cyclodextrin/poly(4‐aminothiophenol)‐Au nanoparticles (CD/PAT‐Aunano) was obtained by the polymerizing in the acid solution initiated by chlorauric acid. The CD/PAT‐Aunano has spherical nanostructure with the average diameter of 55 nm. Glucose oxidase (GOx) was anchored with this complex material and direct electrochemistry of GOx was achieved. A couple of stable and well‐defined redox peaks were observed with the formal potential (E0′) of ‐0.488 V (vs. SCE) in a pH 6.98 buffer solution. The GOx modified electrode also exhibited an excellent electrocatalytic activity to the reduction of glucose, a linearity range for determination of glucose is from 0.25 mM to 16.0 mM with a detection limit of 0.09 mM (S/N = 3). This protocol had potential application to fabricate the third‐generation biosensor. 相似文献
649.
A uric acid (UA) electrochemical biosensor based on the Cu‐Au alloy nanoparticles (NPs) and uricase was developed. The electrodeposition technique of Cu‐Au alloy NPs was selected to be a convenient potentiostatic method at –0.8 V in a single solution containing both Au(III) and Cu2+. Cyclic voltammetry and scanning electron microscopy proved the successful deposition of Cu‐Au alloy NPs. EIS demonstrated the good conductivity of Cu‐Au alloy NPs. The enzyme was immobilized on the surface of Cu‐Au alloy NPs modified electrode by casting with chitosan solution. The ultimate biosensor showed linear amperometric response towards UA in the concentration range of 3.0 to 26.0 μM with a detection limit of 0.8 μM. The main feature of the biosensor was its short response time, which was attributed to the good conductivity of Cu‐Au alloy NPs. Furthermore, the biosensor could avoid the interference of ascorbic acid and oxygen. 相似文献
650.
Jiao-Qiang Zhang Hong-Xu Gao Tie-Zheng Ji Min Chao Hai-Xia Ma Kang-Zhen Xu Rong-Zu Hu 《Journal of Thermal Analysis and Calorimetry》2013,114(1):441-449
1,3-Bis(4-aminophenoxy)benzene (TPER) and poly(amic acid) based on TPER and pyromellitic dianhydride (PMDA) were synthesized. After imidization of the poly(amic acid), polyimide based on TPER and PMDA was obtained. The melting process and the specific heat capacity (C p) of TPER were examined by DSC and microcalorimetry, respectively. The melting enthalpy, the melting entropy, and the C p for TPER were obtained. The enthalpy change, the entropy change, and the Gibbs free energy change for TPER were obtained within 283 and 353 K. The thermal decomposition reaction mechanism of the polyimide is classified from the TG–DTG experimental data, and the thermokinetic parameters of the thermal decomposition reaction are E a = 296.87 kJ mol?1and log (A/s?1) = 14.41. 相似文献