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51.
Pico-second time-resolved time-correlated single photon counting (TCSPC) technique under the total internal reflection (TIR) condition has been used to study the photophysical properties of Coumarin 343 (C343) dye molecules adsorbed at the water/1,2-dichloroethane (DCE) interface. The fluorescence decay profile of C343 under TIR condition at the water/DCE interface was non-exponential and fitted to the double exponential decay function with the fluorescence lifetimes 0.3 and 3.6 ns, which proved the existence of two different forms of C343 species having largely different lifetimes at the interface. The longer fluorescence lifetime component of C343 at the interface is attributed to the emission from the monomeric form of the dye molecules and the shorter lifetime component is due to the aggregation of dye molecules. The penetration depth dependence of decay curves indicated no change in the fluorescence lifetime components, however, the amplitude corresponding to the lifetime of aggregate increased and the amplitude corresponding to the lifetime of monomer decreased with the decrease in penetration depth of the aqueous phase from the interface. Aggregation is significant in the interfacial layer. The decrease in monomer lifetime at the interface compared to that in the bulk solution is interpreted in terms of excitation energy migration between the dye molecules. 相似文献
52.
Bhuvan C. Pant 《Journal of organometallic chemistry》1974,66(3):321-403
Treatment of the lithium reagent from 1,3-bis(trifluoromethyl)benzene (I) with carbon dioxide gave a 60/40 mixture of 2,4- and 2,6-bis(trifluoromethyl)-benzoic acids (IV) and (II). The lithiation/carbonation of 1,3-bis(trifluoromethyl)benzene-5-d (VIII) gave (II) and (IV) without loss of deutrium. This result indicates that (I), unlike trifluoromethylbenzene, does not lithiate meta to a CF3 group. 相似文献
53.
Synthesis and characterization of CdS nanoparticles embedded in a polymethylmethacrylate matrix 总被引:3,自引:0,他引:3
Pedone L Caponetti E Leone M Militello V Pantò V Polizzi S Saladino ML 《Journal of colloid and interface science》2005,284(2):495-500
CdS nanopowder capped with sodium bis(2-ethylhexyl)sulfosuccinate was synthesized by using water-in-oil microemulsions. The CdS nanoparticles of about 5 nm obtained were embedded in polymethylmethacrylate matrix by a photocuring process. The transparent yellow solid compound was characterized by optical absorption and emission spectroscopy, high-resolution transmission electron microscopy, and energy-dispersive X-ray spectroscopy. The properties of this compound were compared with those of the nanopowder dispersed in heptane and in methylmethacrylate. The results obtained indicate that the nanoparticles are homogeneously dispersed in the matrix and do not change in size during the embedding process. Even if the surface slightly changes its luminescence properties, as a consequence of the different new chemical environment, the final product seems to be suitable for practical applications. 相似文献
54.
55.
The electronic structure at a bimetallic interface is obtained using the density functional formalism and a gradient expansion. The charge distribution near the surface is obtained variationally using a simple parameterised form. Application is made to calculate the adhesive energies due to microscopic contacts of pairs of alkali metals. 相似文献
56.
ωL emission from various plane targets irradiated by a 20 J, 5 ns neodymium laser pulse has been investigated. The onset of ωL emission and an increase in intensity by five orders of magnitude is observed at a laser intensity of ≌2×1013W cm-2, the threshold intensity predicted for excitation of the 2ωpe instability. 相似文献
57.
The fluorescence spectra of uranyl complexes with pyridine are described and compared with the known spectra of double salts and addition compounds. In some cases the spectra are of the double salt type whereas in others of the type of addition compounds. The fluorescence spectra of uranyl salts have been generalised into three categories,viz., (i) single reversal and single banded fluorescence spectrum (to which most of the uranyl salts belong), (ii) double reversal and double banded spectrum (to which uranyl sulphate trihydrate belongs) and (iii) single reversal and double banded fluorescence spectrum (to which pyridine uranyl chloride form I belongs). This latter situation is also found in the case of uranium activated alkali fluoride phosphors. The decay times of these complexes are also reported. 相似文献
58.
An intense laser radiation (1012 to 1011 W/cm−2) focused on the solid target creates a hot (≥1 keV) and dense plasma having high ionization state. The multiple charged ions
with high current densities produced during laser matter interaction have potential application in accelerators as an ion
source. This paper presents generation and detection of highly stripped titanium ions (Ti) in laser produced plasma. An Nd:glass
laser (KAMETRON) delivering 50 J energy (λ=0.53 μm) in 2.5 ns was focused onto a titanium target to produce plasma. This plasma
was allowed to drift across a space of ∼3 m through a diagnostic hole in the focusing mirror before ions are finally detected
with the help of electrostatic ion analyzer. Maximum current density was detected for the charge states of +16 and +17 of
Ti ions for laser intensity of ∼1011 W/cm−2. 相似文献
59.
Abstract Experiments carried out demonstrate the production due tosoft X-rays of enhanced ablation pressure. The targets used were planar gold foils. Aluminium targets were also used to demonstrate the relative effect. 相似文献
60.
H. J. Pant V. K. Sharma Gursharan Singh V. K. Raman J. Bornare R. R. Sonde 《Journal of Radioanalytical and Nuclear Chemistry》2012,294(1):59-63
A rotary fluidized bioreactor (RFBR) designed for treatment of wastewater was required to be investigated for its hydrodynamic behaviour and validation of design. A radiotracer investigation was carried out to measure residence time distribution (RTD) of wastewater in the RFBR using 82Br as a radiotracer. The radiotracer was instantaneously injected into the inlet feed line and monitored at the inlet and outlet of the reactor using collimated scintillation detectors connected to a data acquisition system. The measured RTD data was treated and simulated using a tanks-in-series model and model parameters i.e. number of tanks describing the degree of mixing was obtained. The results of the investigation showed no flow abnormalities and the reactor behaved as an ideal continuously stirred-tank reactor at all the operating conditions. Based on the results, the design of the reactor was validated. 相似文献