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91.
Nahid Talebi Burcu Ögüt Wilfried Sigle Ralf Vogelgesang Peter A. van Aken 《Applied Physics A: Materials Science & Processing》2014,116(3):947-954
Plasmonics is expected to play a key role in nanotechnology, leading to intriguing routes in many engineering and biological applications. Recently, it has been realized that toroidal resonances could be an alternative to electric and magnetic resonances, which have governed the innovation of plasmonic applications so far. In a previous contribution, we proved the existence of toroidal moments in an oligomeric void-plasmonic structure [1]. In this article, we investigate the role of topology and symmetry in decomposing the various dipolar, quadrupolar, and toroidal moments, using energy-filtering transmission electron microscopy supported by three-dimensional finite-difference time-domain method simulations. The consequences of changing the topology on the toroidal character are discussed by comparing results obtained from nanoholes forming heptamer and hexamer nanocavity systems that were drilled into a thin silver film. 相似文献
92.
The components of the essential oils (EOs) obtained by solvent-free microwave extraction (SFME) and hydrodistillation (HD) from endemic Origanum saccatum P.H. Davis were identified by using GC/MS. The main constituents of both EOs obtained by SFME and HD, respectively, from O. saccatum were p-cymene (72.5 and 70.6%), thymol (9.32 and 8.11%), and carvacrol (7.18 and 6.36%). The EO obtained by SFME contained substantially higher amounts of oxygenated compounds and lower amounts of monoterpenes than did the EO obtained by HD. The antibacterial activities of the EOs obtained by SFME and HD were evaluated with the disc diffusion method by comparison with 10 different bacterial strains. The antibacterial activity of the EO extracted by SFME was found to be more effective than that of the EO extracted by HD against seven of the tested bacteria. 相似文献
93.
High Dimensional Model Representation (HDMR) method is a technique that represents a multivariate function in terms of less-variate
functions. Even though the method has a finite expansion, to determine the components of this expansion is very expensive
due to integration based natures of the components. Hence, the HDMR expansion is generally truncated at certain multivariance
level and such approximations are produced to represent the given multivariate function approximately. The weight function
selection becomes an important issue for the HDMR based applications when it is desired to give different importances to function
values at different points. An appropriately chosen weight function may increase the quality of the approximation incredibly.
This work aims at a multivariate weight function optimization to obtain high quality approximations through the HDMR method
to represent multivariate functions. The proposed optimization considers constancy measurer maximization which produces a
quadratic vector equation to be solved. Another contribution of this work is to use a recently developed method, fluctuation
free integration, with HDMR, to solve this equation easily. This work is an extension of a previous work about weight optimization
in HDMR for univariate functions. 相似文献
94.
Burcu Karaca Em??lia Csisz??r Faruk Bozdogan 《Plasma Chemistry and Plasma Processing》2011,31(4):623-633
Pectinase enzyme treatment subsequent to atmospheric air- or argon-plasma surface modification was applied in linen fabric preparation. Wettability by water drop test, wickability by thin layer wicking experiment, residual pectin content and colour of the fabrics were characterized. Results clearly proved that the efficiency of pectinase in improving linen water absorbency can be significantly enhanced by plasma pretreatment. Argon-plasma pretreatment followed by a Beisol PRO enzyme treatment reduced the wetting time considerably and resulted in a fabric surface that has been characterized by the lowest water contact angle (86.6??). All the applied treatments increased the energy of the fibre surface. The alkaline scoured, the argon-plasma treated and the argon-plasma-pectinase treated samples have been characterized by the highest $ \gamma_{S}^{total} $ values. Plasma treatment significantly decreased the whiteness and increased the yellowness of the raw fabrics. However, the enzyme treatment applied after the plasma treatment has overcome the colour differences. 相似文献
95.
The anticancer drug, leuprolide (LPR) bound to double-stranded fish sperm DNA (dsDNA) which was immobilized onto the surface of an anodically activated pencil graphite electrode (PGE), was employed for designing a sensitive biosensor. The interaction of leuprolide (LPR) with double-stranded DNA (dsDNA) immobilized onto pencil graphite electrode (PGE) have been studied by electrochemical methods. The mechanism of the interaction was investigated and confirmed by differential pulse voltammetry using two different interaction methods; at the PGE surface and in the solution phase. The decrease in the guanine oxidation peak current was used as an indicator for the interaction in acetate buffer at pH 4.80. The response was optimized with respect to accumulation time, potential, drug concentration, and reproducibility for both interaction methods. The linear response was obtained in the range of 0.20-6.00 ppm LPR concentration with a detection limit of 0.06 ppm on DNA modified PGE and between 0.20 and 1.00 ppm concentration range with detection limit of 0.04 ppm for interaction in solution phase method. LPR showed an irreversible oxidation behavior at all investigated pH values on a bare PGE. Differential pulse adsorptive stripping (AdSDPV) voltammetric method was developed for the determination of LPR. Under these conditions, the current showed a linear dependence with concentration within a range of 0.005-0.20 ppm with a detection limit of 0.0014 ppm. Each determination method was fully validated and applied for the analysis of LPR in its pharmaceutical dosage form. 相似文献
96.
Kirdeciler SK Soy E Oztürk S Kucherenko I Soldatkin O Dzyadevych S Akata B 《Talanta》2011,85(3):1435-1441
A new approach was developed for urea determination where a thin film of silicalite and zeolite Beta deposited onto gold electrodes of a conductometric biosensor was used to immobilize the enzyme. Biosensor responses, operational and storage stabilities were compared with results obtained from the standard membrane methods for the same measurements. For this purpose, different surface modification techniques, which are simply named as Zeolite Membrane Transducers (ZMTs) and Zeolite Coated Transducers (ZCTs) were compared with Standard Membrane Transducers (SMTs). Silicalite and zeolite Beta with Si/Al ratios 40, 50 and 60 were used to modify the conductometric electrodes and to study the biosensor responses as a function of changing zeolitic parameters. During the measurements using ZCT electrodes, there was no need for any cross-linker to immobilize urease, which allowed the direct evaluation of the effect of changing Si/Al ratio for the same type of zeolite on the biosensor responses for the first time. It was seen that silicalite and zeolite Beta added electrodes in all cases lead to increased responses with respect to SMTs. The responses obtained from ZCTs were always higher than ZMTs as well. The responses obtained from zeolite Beta modified ZMTs and ZCTs increased as a function of increasing Si/Al ratio, which might be due to the increased hydrophobicity and/or the acid strength of the medium. 相似文献
97.
The sulfur dioxide adsorption on clinoptilolite-rich tuff from Bigadiç region of Western of Turkey and its modified forms (Na+, K+, Ca2+ and Mg2+) have been studied at 273 K and 293 K up to 100 kPa. The structural properties of clinoptilolites were studied by X-ray diffraction (XRD) and Fourier transform infrared (FT-IR). The quantitative XRD analysis demonstrated that the Natural-B sample is mainly constituted by clinoptilolite (80–85%) with minor contents of quartz (7–8%), feldspar (5–6%) and mica-illit (4–5%). It was found out that the adsorption capacity and the affinity of SO2 with clinoptilolite samples depended mainly on the type of exchanged cations and decreased as Na-B > K-B > Mg-B > Natural-B > Ca-B for both temperature. These results show that clinoptilolite-rich zeolites are considered potentially good adsorbents for SO2 removal. 相似文献
98.
In this study, we describe systematic preparation of a series of aryl-substituted pyridine derivatives. The 1,5-dicarbonyls (3a–i) were prepared in the solvent-free conditions starting from chalcone derivatives (1a–i). The target compounds, 4-aryl-2-(thiophen-3-yl)-6,7-dihydro-5H-cyclopenta[b]-pyridine derivatives (5a–i), were synthesized by a cyclization reaction of the 1,5-dicarbonyls (3a–i) with ammonium acetate (NH4OAc) in acetic acid. The characterization of synthesized compounds was proved by elemental analyses, infrared, mass spectrometry, and 1H and 13C NMR spectroscopy.
[Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.] 相似文献
99.
We study fibre products of a finite number of Kummer covers of the projective line over finite fields. We determine the number of rational points of the fibre product over a rational point of the projective line, which improves the results of Özbudak and Temür (Appl Algebra Eng Commun Comput 18:433–443, 2007) substantially. We also construct explicit examples of fibre products of Kummer covers with many rational points, including a record and two new entries for the current table (http://www.manypoints.org, 2011). 相似文献
100.
Burcu Dogan-Topal 《Journal of Solid State Electrochemistry》2013,17(4):1059-1066
The mechanism of electrochemical oxidation of trifluoperazine has been proposed on the basis of cyclic and differential pulse voltammetry at a multiwalled carbon nanotube-modified glassy carbon electrode. The modified electrode exhibits catalytic activity, high sensitivity, and stability. The oxidation process exhibited an adsorption-controlled behavior. Also, depending on this adsorption control, a sensitive electroanalytical method for the determination of trifluoperazine has been investigated by adsorptive stripping differential pulse voltammetry. Under the optional conditions, the anodic peak current was linear to the trifluoperazine concentration over the range of 2.08 10?8?M to 1.67 10?6?M, and the limit of detection was 7.49 10?10?M. The modified electrode had good stability and repeatability, and it was successfully applied to the determination of trifluoperazine in pharmaceuticals. 相似文献