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951.
Naveen Reddy Kadasala Lu Lin Christopher Gilpin 《Science and Technology of Advanced Materials》2013,14(1):210-218
AbstractAu–FexOy composite nanoparticles (NPs) are of great technological interest due to their combined optical and magnetic properties. However, typical syntheses are neither simple nor ecologically friendly, creating a challenging situation for process scale-up. Here we describe conditions for preparing Au–FexOy NPs in aqueous solutions and at ambient temperatures, without resorting to solvents or amphiphilic surfactants with poor sustainability profiles. These magnetic gold nanoclusters (MGNCs) are prepared in practical yields with average sizes slightly below 100 nm, and surface plasmon resonances that extend to near-infrared wavelengths, and sufficient magnetic moment (up to 6 emu g–1) to permit collection within minutes by handheld magnets. The MGNCs also produce significant photoluminescence when excited at 488 nm. Energy dispersive X-ray (EDX) analysis indicates a relatively even distribution of Fe within the MGNCs, as opposed to a central magnetic core. 相似文献
952.
953.
In this paper, we are interested in the detection of biological molecules. This detection relies on the use of nanosensors based on localized surface-plasmon resonance (LSPR). We discuss the sensitivity of these nanosensors by studying the influence of the concentration of Biotin on the shift of the LSPR wavelength. Moreover, to study the selectivity of these sensors, the systems Biotin/Anti-Biotin (AB) and Biotin/Streptavidin (SA) are used to detect very weak concentration of AB or SA. We found respectively 7 pM and 3 nM for the limits of detection of SA and AB. 相似文献
954.
Homogeneous composite fibers of poly(3-hexylthiophene) (P3HT)-polyethylene oxide (PEO)-Cadmium Sulfide (CdS) were manufactured by electrospinning technique using chloroform as solvent. The incorporation of CdS in the composite fibers was determined by SEM, FTIR and TGA techniques. SEM and confocal microscopy have been used to determine size, surface morphology and distribution of the fluorescence phase in the fibers. A morphology change in P3HT/PEO fibers was caused by the presence of CdS: porous morphology was obtained for low CdS concentration (3.8 wt% and less) and when the content of CdS nanoparticles is higher, they were concentrated at the center of the fibers. The photoluminescence response was modified with CdS inside the P3HT-PEO fibers. By XRD it was determined that the introduction of CdS nanoparticles in the P3HT-PEO fibers caused disorder in P3HT chains. The obtained composite fibers are promising materials for optic and electronic applications. 相似文献
955.
Lna Saint Macary Myrtil L. Kahn Claude Estourns Pierre Fau David Trmouilles Marise Bafleur Philippe Renaud Bruno Chaudret 《Advanced functional materials》2009,19(11):1775-1783
Conditions for the elaboration of nanostructured varistors by spark plasma sintering (SPS) are investigated, using 8‐nm zinc oxide nanoparticles synthesized following an organometallic approach. A binary system constituted of zinc oxide and bismuth oxide nanoparticles is used for this purpose. It is synthesized at room temperature in an organic solution through the hydrolysis of dicyclohexylzinc and bismuth acetate precursors. Sintering of this material is performed by SPS at various temperatures and dwell times. The determination of the microstructure and the chemical composition of the as‐prepared ceramics are based on scanning electron microscopy and X‐ray diffraction analysis. The nonlinear electrical characteristics are evidenced by current–voltage measurements. The breakdown voltage of these nanostructured varistors strongly depends on grain sizes. The results show that nanostructured varistors are obtained by SPS at sintering temperatures ranging from 550 to 600 °C. 相似文献
956.
For demanding applications high steel cleanliness and strictly controlled inclusions are required. Primary inclusions are formed during steel treatments in the ladle. Most of these are removed to the ladle slag or on the lining. However, the rest of the inclusions still remain through the successive process stages, and additionally new inclusions are formed during casting and solidification due to decreasing thermodynamic solubility of oxygen in the steel at lower temperatures, reactions with surrounding slag, refractory materials and eventual contact with air. Inclusions formation and transformation are simulated by thermodynamic calculations in the steel/inclusions/slag system taking into account the solidification phenomena. In this paper inclusions in Si/Mn‐deoxidised steel and Al‐deoxidised Ca‐treated steels are contributed. Calculations are compared with experimental results from steel plants. 相似文献
957.
A method for the synthesis of a new class of anisotropic mesostructured gold material, which we call “mesoflowers”, is demonstrated.
The mesoflowers, unsymmetrical at the single particle level, resemble several natural objects and are made up of a large number
of stems with unusual pentagonal symmetry. The mesostructured material has a high degree of structural purity with star-shaped,
nano-structured stems. The mesoflowers were obtained in high yield, without any contaminating structures and their size could
be tuned from nano- to meso-dimensions. The dependence of various properties of the mesoflowers on their conditions of formation
was studied. The near-infrared-infrared (NIR-IR) absorption exhibited by the mesoflowers has been used for the development
of infrared filters. Using a prototypical device, we demonstrated the utility of the gold mesoflowers in reducing the temperature
rise in an enclosure exposed to daylight in peak summer. These structures showed a high degree of surface-enhanced Raman scattering
(SERS) activity compared to spherical analogues. SERS-based imaging of a single mesoflower is demonstrated. The high SERS
activity and NIR-IR absorption property open up a number of exciting applications in diverse areas.
Electronic Supplementary Material Supplementary material is available in the online version of this article at http://dx.doi.org/ and is accessible free of charge. 相似文献
958.
在既定冶炼条件下,依据炉内反应平衡学原理,导出了炉温定量推算式及铁水[Si]量推算式,其推算结果与实际数据具有良好对应关系,可用于现场操作推算与调控参考。 相似文献
959.
960.
This paper describes the various technological aspects related to adhesive wear of cast aluminium–silicon (Al–Si) alloys. Number of hypothesis and theories proposed in the last two decades in order to explain the different phenomenon related with wear and friction, and influence of test parameters (such as load, sliding speed, counter-surface) and work material properties (like mechanical and metallurgical) on tribological behaviour of aluminium–silicon alloys have been presented and discussed. 相似文献