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601.
Preparation, characterization, and photocatalytic activity of sulfate-modified titania for degradation of methyl orange under visible light 总被引:4,自引:0,他引:4
Parida KM Sahu N Biswal NR Naik B Pradhan AC 《Journal of colloid and interface science》2008,318(2):231-237
Hydrated titania was prepared by a sol-gel method, taking tetraisopropyl orthotitanate as starting material, and then promoted with different weight percentages of sulfate by an incipient wetness impregnation method. The materials were characterized by various advanced techniques such as PXRD, BET surface area, N(2) adsorption-desorption measurements, FTIR, and SEM. Analytical results demonstrated that TiO(2) is mesoporous in nature, and sulfate modification could inhibit the phase transformation and enhance the thermal stability of TiO(2). It was also found that sulfate modification could reduce the crystallite size and increase the specific surface area of the catalysts. The degradation of methyl orange under solar radiation was investigated to evaluate the photocatalytic activity of these materials. Effects of different parameters such as pH of the solution, amount of catalyst, additives, and kinetics were investigated. At 2.5 wt% sulfate loading, the average percentage of degradation of methyl orange was nearly two times than that of neat TiO(2). The photocatalytic degradation followed first-order kinetics. 相似文献
602.
Sharma S Dubey NK Dasgupta AK Sahu M Benjamin B Mullangi R Srinivas NR 《Biomedical chromatography : BMC》2012,26(2):232-238
A highly sensitive, rapid assay method has been developed and validated for the estimation of JI-101 in human plasma and urine using LC-MS/MS-ESI in the positive-ion mode. The assay procedure involves extraction of JI-101 and alfuzosin (internal standard, IS) from human plasma/urine with a solid-phase extraction process. Chromatographic resolution was achieved on two Zorbax SB-C(18) columns connected in series with a PEEK coupler using an isocratic mobile phase comprising acetonitrile-0.1% formic acid in water (70:30, v/v). The total run time was 2.0 min. The MS/MS ion transitions monitored were 466.20 → 265.10 for JI-101 and 390.40 → 156.10 for IS. The method was subjected to rigorous validation procedures to cover the following: selectivity, sensitivity, matrix effect, recovery, precision, accuracy, stability and dilution effect. In both matrices the lower limit of quantitation was 10.0 ng/mL and the linearity range extended from ~10.0 to 1508 ng/mL in plasma or urine. The intra- and inter-day precisions were in the ranges 1.57-14.5 and 6.02-12.4% in plasma and 0.97-15.7 and 8.66-10.2% in urine. This method has been successfully applied for the characterization of JI-101 pharmacokinetics in cancer patients. 相似文献
603.
Ion transport behavior in a mechanochemically synthesized silver halide mixed composite has been investigated. AgI and AgCl, in 75: 25 mol. wt. (%) ratio, has been prepared by high energy ball milling for different milling times viz. 5, 10, 20, 30, 40, and 50 h as well as by simple physical mixing (referred to as zero hour milling). The room temperature conductivity has been evaluated as a function of milling time. The conductivity increased initially with increasing milling time, then decreased. The increase in conductivity has been attributed to the increased degree of amorphosity in the sample as a consequence of high energy ball milling. The 30-hour milled sample exhibited highest conductivity with an enhancement of more an order of magnitude from that of zero hour milled sample. To explain the ion transport mechanism in the optimum conducting sample, other basic ionic parameters viz. ionic mobility (μ), mobile ion concentration (n), ionic transference number (tion) etc. have also been determined. The materials and structural properties have been characterized using XRD, FTIR, and DSC techniques. Using the optimum conducting sample as electrolyte, all-solid-state battery has been fabricated having cell configuration: Ag (anode) // (0.75 AgI:0.25AgCl) // C + I2 + Electrolyte (cathode), and the cell performance has been studied under varying load conditions. 相似文献
604.
Sahu K Ghosh S Mondal SK Ghosh BC Sen P Roy D Bhattacharyya K 《The Journal of chemical physics》2006,125(4):44714
Ultrafast fluorescence resonance energy transfer (FRET) from coumarin 153 (C153) to rhodamine 6G (R6G) is studied in a neutral PEO(20)-PPO(70)-PEO(20) triblock copolymer (P123) micelle and an anionic micelle (sodium dodecyl sulfate, SDS) using a femtosecond up-conversion setup. Time constants of FRET were determined from the rise time of the acceptor emission. It is shown that a micelle increases efficiency of FRET by holding the donor and the acceptor at a close distance (intramicellar FRET) and also by tuning the donor and acceptor energies. It is demonstrated that in the P123 micelle, intramicellar FRET (i.e., donor and acceptor in same micelle) occurs in 1.2 and 24 ps. In SDS micelle, there are two ultrafast components (0.7 and 13 ps) corresponding to intramicellar FRET. The role of diffusion is found to be minor in the ultrafast components of FRET. We also detected a much longer component (1000 ps) for intramicellar FRET in the larger P123 micelle. 相似文献
605.
We present a scalar triplet extension of the standard model to unify the origin of inflation with neutrino mass, asymmetric dark matter and leptogenesis. In presence of non-minimal couplings to gravity the scalar triplet, mixed with the standard model Higgs, plays the role of inflaton in the early Universe, while its decay to SM Higgs, lepton and dark matter simultaneously generate an asymmetry in the visible and dark matter sectors. On the other hand, in the low energy effective theory the induced vacuum expectation value of the triplet gives sub-eV Majorana masses to active neutrinos. We investigate the model parameter space leading to successful inflation as well as the observed dark matter to baryon abundance. Assuming the standard model like Higgs mass to be at 125–126 GeV, we found that the mass scale of the scalar triplet to be ?O(109) GeV and its trilinear coupling to doublet Higgs is ?0.09 so that it not only evades the possibility of having a metastable vacuum in the standard model, but also lead to a rich phenomenological consequences as stated above. Moreover, we found that the scalar triplet inflation strongly constrains the quartic couplings, while allowing for a wide range of Yukawa couplings which generate the CP asymmetries in the visible and dark matter sectors. 相似文献
606.
We analyze the strain induced changes in the low temperature multisubband electron mobility mediated through the intersubband interactions in a pseudomorphic GaAs/InxGa1−xAs coupled double quantum well structure. We consider the non-phonon scattering mechanisms and study the effect of strain on them. We show that strain reduces the mobility due to ionized impurity (imp-) scattering μimp but enhances the mobility due to interface roughness (IR-) scattering μIR. For alloy disorder (AL-) scattering as long as the lowest subband is occupied, the effect of strain enhances the mobility μAL. However, once the second subband is occupied, there is almost no change, rather decrease in μAL for larger well widths. It is gratifying to note that for single subband occupancy, the effect of strain enhances the total mobility μ. On the other hand, for double subband occupancy, initially there is almost no change, but with increase in well width the total mobility reduces. We vary the In composition x from 0.15 to 0.2 and 0.25 and the barrier width between the two wells to analyze their effects on the mobility which shows interesting results. Our study of multisubband mobility can be utilized for the low temperature device applications. 相似文献
607.
This work investigates the effect of NaF on optical and structural properties of nano crystalline CdxZn1?xS films. The CdxZn1?xS films are prepared through chemical bath deposition (CBD) technique in aqueous alkaline bath and their subsequent condensation on substrates. The as-obtained samples are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV–VIS absorption spectroscopy. Micro structural features, obtained from XRD analysis confirm the formation of cubic phase of undoped as well as NaF doped CdxZn1?xS nano particles while SEM observations depict non-uniform distribution of grains. These results show the average grain size of pure as well as NaF doped samples to range from 50 to 90 nm. Tauc's plots, extracted from absorption spectra exhibit absorption to be dominating mainly in blue-green region of visible spectrum. The room-temperature photoluminescence (PL) spectra of CdxZn1?xS samples show a peak around 425 nm, which gets blue shifted for doped sample indicating improvement in PL properties on its addition. 相似文献
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