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排序方式: 共有213条查询结果,搜索用时 15 毫秒
141.
Chowdhury MH Malyn SN Aslan K Lakowicz JR Geddes CD 《The journal of physical chemistry. B》2006,110(45):22644-22651
In reports over the past several years, we have demonstrated the efficient collection of optically excited fluorophore emission by its coupling to surface plasmons on thin metallic films, where the coupled luminescence was highly directional and polarized. This phenomenon is referred to as surface plasmon-coupled emission (SPCE). In this current study, we have extended this technique to include chemiluminescing species and subsequentially now report the observation of surface plasmon-coupled chemiluminescence (SPCC), where the luminescence from chemically induced electronic excited states couples to surface plasmons in thin continuous metal films. The SPCC is highly directional and predominantly p-polarized, strongly suggesting that the emission is from surface plasmons instead of the luminophores themselves. This indicates that surface plasmons can be directly excited from chemically induced electronic excited states and excludes the possibility that the plasmons are created by incident excitation light. This phenomenon has been observed for a variety of chemiluminescent species in the visible spectrum, ranging from blue to red, and also on a variety of metals, namely, aluminum, silver, and gold. Our findings suggest new chemiluminescence sensing strategies on the basis of localized, directional, and polarized chemiluminescence detection, especially given the wealth of assays that currently employ chemiluminescence-based detection. 相似文献
142.
Poly(vinyl phosphonic acid) (PVPA)-Fe3O4 nanocomposite is synthesized by the precipitation of Fe3O4 in the presence of PVPA. Structural, surface, morphological, thermal properties and conductivity characterization/evaluation of the nanocomposite were performed by XRD, FT-IR, TEM, TGA and conductivity measurements respectively. The capping of PVPA around the Fe3O4 nanoparticles was confirmed by FT-IR spectroscopy, the interaction being via bridging oxygens of the phosphate and the nanoparticle surface. The crystallite and particle size were obtained as 6 ± 2 and 8.7 ± 0.1 nm from XRD line profile fitting and TEM image analysis respectively, which reveal nearly single crystalline nature of the Fe3O4 nanoparticles. Magnetic characterization of the bulk magnetite and (PVPA)-Fe3O4 nanocomposite reveals that both are in the superparamagnetic state at room temperature. The average magnetic domain size of the nanoparticles has been calculated using the Langevin function, which was fitted to the measured M-H hysteresis curves as 7.6 nm for the nanocomposite. In the nanocomposite, the reduction is due to the adsorption of PVPA onto the magnetite surface, which cancels some of the free spins at the surface causing a magnetically dead layer. Analysis of the conductivity and permittivity measurements revealed the coupling of ionic and polymer segmental motions and strong temperature dependency in the nanocomposite. 相似文献
143.
Cu Nanoparticles Electrodeposited at Liquid–Liquid Interfaces: A Highly Efficient Catalyst for the Hydrogen Evolution Reaction
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Emre Aslan Dr. Imren Hatay Patir Prof. Dr. Mustafa Ersoz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(12):4585-4589
The electrochemical deposition of Cu nanoparticles with an average diameter of approximately 25–35 nm has been reported at liquid–liquid interfaces by using the organic‐phase electron‐donor decamethylferrocene (DMFc). The electrodeposited Cu nanoparticles display excellent catalytic activity for the hydrogen evolution reaction (HER); this is the first reported catalytic effect of Cu nanoparticles at liquid–liquid interfaces. 相似文献
144.
mür Kvan Kürkü Ersin Aslan Mehmet Sezer 《Mathematical Methods in the Applied Sciences》2019,42(18):6114-6130
In this study, fractional differential equations having quintic nonlinearity are considered by proposing an accurate numerical method based on the matching polynomial and matrix‐collocation system. This method provides an integration between matrix and fractional derivative, which makes it fast and efficient. A hybrid computer program is designed by making use of the fast algorithmic structure of the method. An error analysis technique consisting of the fractional‐based residual function is constructed to scrutinize the precision of the method. Some error tests are also performed. Figures and tables present the consistency of the approximate solutions of highly stiff model problems. All results point out that the method is effective, simple, and eligible. 相似文献
145.
Alexander Vladimirovich Ivanov Mariya Petrovna Kruglova Edward Danielevich Virus Polina Olegovna Bulgakova Sergei Vital'evich Grachev Aslan Amirkhanovich Kubatiev 《Electrophoresis》2020,41(3-4):209-214
A new approach for direct determination of S-adenosylmethionine (SAM), S-adenosylhomocysteine (SAH), and methylthioadenosine (MTA) in urine was developed based on MEKC by using SDS modified with isobutanol in the presence of PEG-300. Analytes were first extracted with grafted phenylborononic acid. Using a 50 µm internal diameter silica capillary of 32 cm total length filled with 0.05 M SDS, 0.05 M H3PO4, 5% (v/v) isobutanol, and 10% (v/v) PEG-300, LOQ of 0.15 µM for SAM and SAH, and 0.2 µM for MTA was reached. Accuracy was 92% for MTA, 109% for SAH, and 105% for SAM, intra- and interday imprecision were <2.5 and ≤3%, respectively. The total time of analysis for one sample was 10 min. Analysis of 30 urine samples from healthy volunteers showed that the median SAM and SAH levels were 12.1 and 0.73 µM, respectively. MTA levels, which were determined in urine for the first time (according to our data), were 0.43 µM, and these values correlated well with the SAM level (r = 0.748, p < 0.01). 相似文献
146.
The reaction between phenylmagnesium bromide and hexachlorocyclotriphophazene (N 3 P 3 Cl 6 ) ( 1 ) was reinvestigated for the synthesis of hexaphenylcyclotriphosphazene (N 3 P 3 Ph 6 ) ( 2 ) in high yield. The reaction is complete within two weeks at room temperature using toluene as solvent. When the reactants (PhMgBr and N 3 P 3 Cl 6 ) were employed in a 6:1, 36:1 and 72:1 molar ratio, compound 2 was obtained in 2.6%, 14%, and 33.4% yield, respectively. The formation of N 3 P 3 Cl 6 ( 2 ) during the reaction was followed by thin-layer chromatography. Compound 2 was characterized by elemental analysis, IR, UV-VIS, 1 H, 13 C, and 31 P NMR spectroscopy as well as by mass spectrometry. 相似文献
147.
148.
The theory of internal photoemission in semiconductor heterojunctions has been reviewed and the existing model has been extended by incorporating the effects of the difference in the effective masses in the active region and the substrate, nonspherical-nonparabolic bands, and the energy loss per collisions. This complete model has been applied to describe the experimental results obtained from Si1−xGex/Si heterojunction infrared photodetectors. The barrier heights (correspondingly the cut-off wavelengths) of SiGe/Si samples have been determined from their internal photoemission spectra by using the extended model which has the wavelength and doping concentration dependent free carrier absorption parameters. Fowler analysis showed that the model is in good agreement with the experiments for the entire spectrum. 相似文献
149.
In this Rapid Communication, we present the development of monodisperse core-shell (silver core-silica shell) nanoparticles
with various shell thicknesses featuring a fluorophore, subsequently named Metal-Enhanced Fluorescence (MEF) nanoballs. MEF
nanoballs consist of a ≈130 nm silver nanoparticle core, a silica shell with up to 35 nm thickness and fluorophores doped within the silica shell.
Fluorescent nanobubbles where the silver core is removed by chemical etching are used as control samples to show the benefits
of using silver nanoparticles, i.e, Metal-Enhanced Fluorescence. Finally, we demonstrate the broad potential biological applications
of MEF nanoballs by employing near-infra red emitting probes (Rhodamine 800) within the silica shell, for potential applications
in cellular imaging and solution-based sensing.
Kadir Aslan, Meng Wu, Contributed equally 相似文献
150.
In this paper, we describe an optical geometry that facilitates our further characterization of the temperature changes above
silver island films (SiFs) on sapphire plates, when exposed to microwave radiation. Since sapphire transmits IR, we designed
an optical scheme to capture real-time temperature images of a thin water film on sapphire plates with and without SiFs during
the application of a short microwave pulse. Using this optical scheme, we can accurately determine the temperature profile
of solvents in proximity to metal structures when exposed to microwave irradiation. We believe that this optical scheme will
provide us with a basis for further studies in designing metal structures to further improve plasmonic-fluorescence clinical
sensing applications, such as those used in microwave accelerated metal-enhanced fluorescence (MAMEF). 相似文献