排序方式: 共有27条查询结果,搜索用时 15 毫秒
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Edith Chow Burkhard Raguse Karl‐H. Müller Lech Wieczorek Avi Bendavid James S. Cooper Lee J. Hubble Melissa S. Webster 《Electroanalysis》2013,25(10):2313-2320
The porosity of 1‐hexanethiol‐functionalised gold nanoparticle films was assessed and utilised as chemiresistor sensors. Electrochemical capacitance measurements showed that the accessibility of electrolytes of different ionic strengths into the pores depended on the thickness of the electric double layer formed. A large variation in capacitance was measured in 0.01–1000 mM NaClO4, implying a wide pore size distribution. The change in morphology of the nanoparticle films upon storage in air, water and ethanol for two weeks was investigated. There was a significant decrease in the electrochemical capacitance at high electrolyte concentrations for the ethanol‐stored films compared to the freshly‐prepared films suggesting a decrease in the number of small pores of radii in the range of 0.3–3 nm. This was further supported by optical topographical measurements where a decrease in the thickness of ethanol‐stored films was observed relative to the freshly‐prepared films. The porous nature of the nanoparticle films was found to have an effect on the chemical sensing behaviour. When used as chemiresistor sensors, for the detection of heptane in water, the ethanol‐stored films provided larger resistance changes and longer response times. This suggests that the more densely packed ethanol‐stored films provided more sites that enabled film swelling, and that diffusion of the analyte occurred through the narrower water‐filled pores. This demonstrates the effect of different storage conditions on film morphology and subsequently sensor response. 相似文献
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Yan-Fen Li Dalton G. Hubble Russell G. Miller Hou-Yin Zhao Wei-Ping Pan Sean Parkin Bangbo Yan 《Polyhedron》2010
Two new hybrid compounds, [Co(4,4′-bpy)2(H2O)4][(4,4′-bpyH2]2[CoW12O40]·8H2O (1) and [Fe(2,2′-bpy)3]3[H2W12O40]·6H2O (2), (4,4′-bpy = 4,4′-bipyridine, 2,2′-bpy = 2,2′-bipyridine) have been hydrothermally synthesized. These solids were characterized by elemental analysis, thermogravimetric analysis, UV–Vis spectroscopy and X-ray diffraction. The hydrogen-bonding interactions in 1 lead to the formation of a three dimensional network consisting of [CoW12O40]6− anionic clusters, [Co(4,4′-bpy)2(H2O)4]2+ cations and lattice water molecules, while the discrete Keggin ion [H2W12O40]6− in compound 2 is surrounded by 14 [Fe(2,2′-bpy)3]2+ complexes through CH?O interactions (2.24–2.56 Å). 相似文献
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Martin AD Boulos RA Hubble LJ Hartlieb KJ Raston CL 《Chemical communications (Cambridge, England)》2011,47(26):7353-7355
p-Phosphonic acid calix[5]arene forms molecular capsules in water based on two of the molecules, which can be loaded with carboplatin using intense shearing, and attached to single wall carbon nano-tubes. Spin coating of the capsules onto a substrate affords 2 nm fibres of stacked calixarenes, with the self-assembly understood using molecular modelling. 相似文献
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Sharma SK Lucey PG Ghosh M Hubble HW Horton KA 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2003,59(10):2391-2407
We have designed and developed two breadboard versions of stand-off Raman spectroscopic systems for landers based on a 5-in. Maksutov-Cassegrain telescope and a small (4-in. diameter) Newtonian telescope receiver. These systems are capable of measuring the Raman spectra of minerals located at a distance of 4.5-66 m from the telescope. Both continuous wave (CW) Ar-ion and frequency doubled Nd:YAG (532 nm) pulsed (20 Hz) lasers are used as excitation sources for measuring remote Raman spectra of rocks and minerals. We have also made complementary measurements on the same rock samples with a micro-Raman system in 180 and 135 degrees geometry for evaluating the system performance and for estimating effect of grain size and laser-induced heating on the spectra of minerals using alpha-quartz as a model mineral. A field portable remote pulsed Raman spectroscopic system based on the 5-in. telescope and an f/2.2 spectrograph has been developed and tested. We have also demonstrated a prototype of a combined Raman and laser-induced breakdown spectroscopy (LIBS) system, capable of providing major element composition and mineralogical information on both biogenic and inorganic minerals at a distance of 10 m from the receiver. 相似文献
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Bruins EE Bauer TS den Bok HW Duif CP van Hoek WC de Lange DJ Misiejuk A Papandreou Z Sichtermann EP Tjon JA Willering HW Yeomans DM Reike H Durek D Frommberger F Gothe R Jakob D Kranefeld G Kunz C Leiendecker N Pfeiffer G Putsch H Reichelt T Schoch B Wacker D Wehrmeister D Wilhelm M Jans E Konijn J de Vries R Furget C Voutier E Arenhövel H 《Physical review letters》1995,75(1):21-24
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