Quasiparticle nature of rotational bands in Pt-187

The high-spin states in Pt-187 have been studied experimentally by means of in-beam gamma-ray spectroscopy techniques via the Yb-173(O-18, 4n) fusion-evaporation reaction. The high-spin level scheme of Pt-187 has been established, including three rotational bands. Based on the systematics of level structure in neighboring nuclei and by comparing the experimental and theoretical B(M1)/B(E2) ratios, configurations of 11/2+ [615], 7/2(-)[5031 and 1/2(-)[521] have been proposed for the three rotational bands, respectively. Band properties of band crossing frequency, alignment gain and signature splitting have been discussed.

Search for signature inversion in the pi i(13/2)circle times nu i(13/2) bands in Au-182,Au-184,Au-186

Search for low-spin signature inversion in the pi i(13/2) circle times nu i(13/2) bands in odd-odd Au-182,Au-184,Au-186 has been conducted through the standard in-beam gamma-spectroscopy techniques via the Sm-152(Cl-35,5n) Au-182, Yb-172(F-19,5n) (186)An, and Tb-159(Si-29,4n) (184)An reactions, respectively. The pi i(13/2) circle times nu i(13/2) bands in these three nuclei have been identified and extended up to high-spin states. In particular, the inter-band connection between the pi i(13/2) circle times nu i(13/2) band and the ground-state band in Au-184 has been established, leading to a firm spin-and-parity assignment for the pi i(13/2) circle times nu i(13/2) band. The low-spin signature inversion is found in the pi i(13/2) circle times nu i(13/2) bands according to our spin-assignment and-the signature crossing observed at high-spin states.

Low-spin signature inversion in the pi h(9/2)circle times nu i(13/2) oblate band

Excited states in Tl-188,Tl-190 have been studied experimentally by means of in-beam gamma spectroscopy techniques, and resulted in the identification of a strongly coupled band based on the pi h(9/2) circle times nu i(13/2) configuration with oblate deformation. The oblate band in doubly odd Tl nuclei shows low-spin signature inversion. It is the first experimental observation of low-spin signature inversion for a band associated with the oblate pi h(9/2) circle times nu i(13/2) configuration.

Quantitative electrochemiluminescence detection of proteins: Avidin-based sensor and tris(2,2 '-bipyridine) ruthenium(II) label

Quantitative electrochemilumineseence (ECL) detection of a model protein, bovine serum albumin (BSA) was achieved via biotin-avidin interaction using an avidin-based sensor and a well-developed ECL system of tris(2,2'-bipyridine) ruthenium(II) derivative as label and tri-n-propylamine (TPA) as coreactant. To detect the protein, avidin was linked to the glassy carbon electrode through passive adsorptions and covalent interaction with carboxylate-terminated carbon nanotubes that was used as binder to immobilize avidin onto the electrode. Then, biotinylated BSA tagged with tris(2,2'-bipyridine) ruthenium(II) label was attached to the prepared avidin surface.

One-pot green synthesis of biocompatible arginine-stabilized magnetic nanoparticles

A green one-step approach has been developed for the synthesis of amino-functionalized magnetite nanoparticles. The synthesis was accomplished by simply mixing FeCl2 with arginine under ambient conditions. It was found that the Fe2+/arginine molar ratio, reaction duration and temperature greatly influence the size, morphology and composition of magnetic nanoparticles. The arginine-stabilized magnetic nanoparticles were characterized by transmission electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, thermogravimetric analysis, and Fourier transform infrared spectroscopy techniques.

Preparation and Electrical Properties of New Oxide Ion Conductors Ce6-xGdxMoO15-delta (0.0 <= x <= 1.8)

A series of oxide ion conductors Ce6-xGdxMoO15-delta (0.0 <= x <= 1.8) have been prepared by the sol-gel method. Their properties were characterized by differential thermal analysis/thermogravimetry (DTA/TG), X-ray diffraction (XRD), Raman, IR, X-ray photoelectron spectroscopy (XPS), and AC impedance spectroscopy. The XRD patterns showed that the materials were single phase with a cubic fluorite structure. The conductivity of Ce6-xGdxMoO15-delta increases as x increases and reaches the maximum at x = 0.15. The conductivity of Ce4.5Gd1.5MoO15-delta is sigma(t) = 3.6 x 10(-3) S/cm at 700 degrees C, which is higher than that of Ce4.5/6Gd1.5/6O2-delta (sigma(t) = 2.6 x 10(-3) S/cm), and the corresponding activation energy of Ce4.5Gd1.5MoO15-delta (0.92 eV) is lower than that of Ce4.5/6Gd1.5/6O2-delta (1.18 eV).

Synthesis and Electrical Properties of New Solid State Electrolyte Materials Ce6-xHoxMoO15-delta(0.0 <= x <= 1.2)

Ce6-xHoxMoO15-delta(0.0 <= x <= 1.2) was synthesized by modified sol-gel method and characterized by differential X-ray diffraction(XRD), Raman, and X-ray photoelectron spectroscopy(XPS) methods. The oxide ionic conductivity of the samples was investigated by AC impedance spectroscopy. It shows that all the samples are single phase with a cubic fluorite structure. The solid solution Ce6-xHoxMoO15-delta(x=0.6) was detected to be the best conducting phase with the highest conductivity(sigma(t)=1.05x10(-2) S/cm) at 800 degrees C and the lowest activation energy(E-a=1.09 eV). These properties suggest that this kind of material has a potential application in intermediate-low temperature solid oxide fuel cells.

Electrochemiluminescence sensor based on partial sulfonation of polystyrene with carbon nanotubes

Herein, homogenously partial sulfonation of polystyrene (PSP) was performed. An effective electrochemiluminescence (ECL) sensor based on PSP with carbon nanotube (CNTs) composite film was developed. Cyclic voltammetry and electrochemical impendence spectroscopy were applied to characterize this composite film. The PSP was used as an immobilization matrix to entrap the ECL reagent Ru(bpy)(3)(2+) due to the electrostatic interactions between sulfonic acid groups and Ru(bpy)(3)(2+) cations. The introduction of CNTs into PSP acted not only as a conducting pathway to accelerate the electron transfer but also as a proper matrix to immobilize Ru(bpy)(3)(2+) on the electrode by hydrophobic interaction. Furthermore, the results indicated the ECL intensity produced at this composite film was over 3-fold compared with that of the pure PSP film due to the electrocatalytic activity of the CNTs. Such a sensor was verified by the sensitive determinations of 2-(dibutylamino)ethanol and tripropylamine.

Molecular "Wiring" glucose oxidase in supramolecular architecture

Supramolecular organized multilayers were constructed by multiwalled carbon nanotubes modified with ferrocene-derivatized poly(allylamine) redox polymer and glucose oxidase by electrostatic self-assembly. From the analysis of voltammetric signals and fluorescence results, a linear increment of the coverage of enzyme per bilayer was estimated, which demonstrated that the multilayer is constructed in a spatially ordered manner. The cyclic voltammograms obtained from the indium tin oxide (ITO) electrodes coated by the (Fc-PAH@CNT/GOx)(n) multilayers revealed that bioelectrocatalytic response is directly correlated to the number of deposited bilayers; that is, the sensitivity is tunable by controlling the number of bilayers associated with ITO electrodes. The incorporation of redox-polymer-functionalized carbon nanotubes (CNT) into enzyme films resulted in a 6-10-fold increase in the glucose electrocatalytic current; the bimolecular rate constant of FADH(2) oxidation (wiring efficiency) was increased up to 12-fold. Impedance spectroscopy data have yielded the electron diffusion coefficient (D-e) of this nanostructure to be over 10(-8) cm(2) s(-1), which is typically higher than those systems without CNT by at least a factor of 10, indicating that electron transport in the new supramolecular architecture was enhanced by communication of the redox active site of enzyme, redox polymer, and CNT.

Fast densification and electrical conductivity of yttria-stabilized zirconia nanoceramics

Nanocrystalline 8YSZ (8 mol% yttria stabilized zirconia) bulk samples with grain sizes of 20-30 nm were synthesized by Sol-Gel method and then densified under a high pressure of 4.5 GPa at 1273 K for 10 min. The method led to the densification of 8YSZ to a relative density higher than 92% without grain growth. Fourier transmission Raman spectroscopy suggested that 8YSZ underwent a phase transition from the cubic phase to a phase mixture (tetragonal plus a trace of monoclinic) after the densification, which decreased the electrical conductivity to a certain degree as concluded from the impedance spectroscopy.

Structure and electrical properties of Pr ans Sm doped CeO2 and Ce2MoO15 based solid electrolytes

Sin and Pr doped CeO2 and Ce6MoO15 based materials were synthesized by sol-gel method. The structure of the powders were characterized by X-ray diffraction (XRD), Raman spectra, field emission scanning electron microscopy(FE-SEM) and the electrical conductivity of the samples was investigated by AC impedance spectroscopy. By comparing the structure and electrical properties of different systems, it could be concluded that the electrical property of Ce6MoO15 based system is better than that of CeO2 system. The added Mo element resulted in the increase of gain size and improved the grain boundary conductivity notably below 600 degrees C, while the Pr dopant induced the smaller grain size and improved the grain boundary conductivity of the materials.

Effects of Pr dopant on grain boundary and electrical properties of Ce5.2Sm0.8MoO15-delta

Material formulated as Ce5.2Sm0.8-xPrxMo15-(delta) (x=0.08) was prepared by adding small amounts of Pr dopant in oxide Ce5.2SM0.8-xPrxMoO15-delta. Structural and electrical properties were investigated by means of X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM) and AC impedance spectroscopy. The effect of small amounts of Pr on microstructure and electrical conductivity was discussed. It was showed that the material doped with Pr has a lot of dents and small openings, which provide channels for oxygen ions, resulting in lower grain boundary and total conductivity activation energy. Thus the corresponding grain boundary conductivity and total conductivity of the material were improved notably. The grain boundary conductivity of the material doped with Pr is 6.79 X 10(-3) S center dot cm(-1) at 500 degrees C, which is twice as large as that without Pr (5.61 X 10(-5) S center dot cm(-1)).

Synthesis and electrical properties of new solid state. Electrolyte materials Ce5.2RE0.8MoO15-delta

A series of solid state electrolytes, Ce-5.2 RE0.8 MoO15-delta (RE = Y, La, Sm, Gd, Dy, Ho, Er), were synthesized by sol-gel method. Their structures and electrical conductivities were characterized by X-ray Diffraction (XRD), Raman and X-ray Photoelectron Spectroscopy (XPS) and AC impedance spectroscopy, respectively. The results show that the concentrations of oxygen vacancy increased with increasing x and their conductivity were improved. And the cell parameters increase as the radius of RE3+ increases. Because the ionic radius of doped Dy3+ (0.0908 nm) is closed to that of Ce4+ (0.0920 nm), their oxide has minimal cell elastic straining between RE3+ and oxygen vacancy, and the system has the least association enthalpy, thus the oxide Ce-5.2 Dy-0.8 MoO15-delta exhibits a higher conductivity (7.02 x 10(-3) S/cm) and lower activation energy (1.056 eV) compared to the other doped compounds.

Preparation, structure and oxide ion conductivity in Ce6-xYxMoO15-delta (x=0.1-1.4) solid solutions

The Ce6-xYxMoO15-delta solid solution with fluorite-related structure have been characterized by differential thermal analysis/thermogravimetry (DTA/TG), X-ray diffraction (XRD), IR, Raman, scanning electric microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) methods. The electric conductivity of samples is investigated by Ac impedance spectroscopy. An essentially pure oxide-ion conductivity of the oxygen-deficiency was observed in pure argon, oxygen and air. The highest oxygen-ion conductivity was found in Ce5.5Y0.5MoO15-delta ranging from 5.9 X 10(-5)(S cm(-1)) at 300 degrees C to 1.3 X 10(-2)(S cm(-1)) at 650 degrees C, respectively. The oxide-ion conductivities remained stable over 80 h-long test at 800 degrees C. These properties suggested that significant oxide-ionic conductivity exists in these materials at moderately elevated temperatures.

Properties of a nanocomposite polymer electrolyte from an amorphous comb-branch polymer and nanoparticles

Three fully amorphous comb-branch polymers based on poly(styrene-co-maleic anhydride) as a backbone and poly(ethylene glycol) methyl ether of different molecular weights as side chains were synthesized. SiO2 nanoparticles of various contents and the salt LiCF3SO3 were added to these comb-branch polymers to obtain nanocomposite polymer electrolytes. The thermal and transport properties of the samples have been characterized. The maximum conductivity of 2.8x10(-4) S cm(-1) is obtained at 28 degreesC. In the system the longer side chain of the comb-branch polymer electrolyte increases in ionic conductivity after the addition of nanoparticles. To account for the role of the ceramic fillers in the nanocomposite polymer electrolyte, a model based on a fully amorphous comb-branch polymer matrix in enhancing transport properties of Li+ ions is proposed.