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991.
We measure intensity statistics and identify statistical regimes and crossovers in random lasers based on nonresonant feedback. A single parameter extracted from an α-stable Levy fit is used to characterize the intensity distributions in all regimes. Measurements made over a range of scattering strengths, excitation energies, and sample sizes enable us to demarcate three regimes of intensity statistics and the corresponding crossovers. An initial subthreshold Gaussian regime abruptly transits into a Levy regime at the random lasing threshold, which is followed by a continuous gradual crossover toward a second Gaussian regime. We find that the prominence of the Levy regime depends upon the sample size. 相似文献
992.
We demonstrate coherent random lasing from an aerosol of dye-doped microdroplets in air. The aerosol is in the form of a linear array of polydisperse, arbitrarily shaped, and randomly spaced microdroplets with average dimensions of about 30 μm. Upon optical excitation, ultranarrow lasing modes were observed in the emission along the axis of the linear array, while the transverse emission exhibited intrascatterer resonance peaks. Direct spatiospectral imaging and lasing threshold studies confirmed the origin of the lasing peaks to be from spatial modes that extended over the array of the polydisperse microdroplets. 相似文献
993.
In the present paper, we report about synthesis of nanostructured organic–inorganic heterojunction of CdS/Polyaniline/CuInSe2 thin films by cost effective chemical route at room temperature, for solar cell application. As such obtained thin films are characterized for structural, compositional, morphological, optical and electrical properties by X-ray diffraction (XRD) pattern, energy dispersive X-ray (EDAX) analysis, scanning electron microscopy (SEM), optical absorbance spectra and I–V response respectively. The XRD reveals the polycrystalline nature of the thin films having tetragonal crystal structure and a crystallite size of 19 nm. The presence of observed and expected elements in the EDAX spectra confirms the elemental compositions in CdS/Polyaniline/CuInSe2 thin films. From SEM images it can be inferred that the surface morphology of the Polyaniline thin films exists like clothing fibers, while CdS/CuInSe2 shows granular shape particles distributed over the substrate and the SEM of CdS/Polyaniline/CuInSe2 represents mixing and attachment of circular particles to fiber like structure. The optical absorbance spectra have shown red shift in absorbance strength and energy band gap value of CdS/CuInSe2 from ~ 1.36 eV to ~ 1.62 eV upon formation of CdS/Polyaniline/CuInSe2 thin film. The I–V response of CdS/CuInSe2 and CdS/Polyaniline/CuInSe2 measured under dark and illumination to 100 mW/cm2 light, exhibited the solar characteristics from these graphs and the conversion efficiency calculated is observed to be 0.26 and 0.55% for CdS/CuInSe2 and CdS/Polyaniline/CuInSe2 thin films respectively. 相似文献
994.
Zoltan Homonnay Peter Buszlai Judit Nádor Virender K. Sharma Erno Kuzmann Attila Vértes 《Hyperfine Interactions》2012,205(1-3):17-21
The reaction of the μ-oxo-diiron(III)-L complex (L = EDTA, ethylene diamine tetraacetate, HEDTA, hydroxyethyl ethylene diamine triacetate, and CyDTA, cyclohexane diamine tetraacetate) with peroxynitrite in alkaline solution was studied by M?ssbauer spectroscopy using rapid-freezing technique. These complexes yield an (L)FeIII(η 2-O $_{2})^{3-}$ complex ion when they react with hydrogen peroxide and the formation of the peroxide adduct results in a deep purple coloration of the solution. The same color appears when the reaction occurs with peroxinitrite. Although spectrophotometry indicated some difference between the molar extinction coefficients of the peroxo and the peroxinitrito adducts, the M?ssbauer parameters proved to be the same within experimental error. It is concluded that the peroxynitrite ion decomposes when reacting with FeIII(L) and the peroxo adduct forms. 相似文献
995.
Rajneesh Kumar Pankaj Sharma P. B. Barman Vineet Sharma S. C. Katyal V. S. Rangra 《Journal of Thermal Analysis and Calorimetry》2012,110(3):1053-1060
The present article deals with the differential scanning calorimetric (DSC) study of Se?CTe glasses containing Sn. DSC runs are taken at four different heating rates (10, 15, 20 and 25?K?min?1). The crystallization data are examined in terms of modified Kissinger, Matusita equations, Mahadevan method and Augis and Bennett approximation for the non-isothermal crystallization. The activation energy for crystallization (E c) is evaluated from the data obtained at different heating rates. Activation energy of glass transition is calculated by Kissinger??s relation and Moynihan theory. The glass forming tendency is also calculated for each composition. The glass transition temperature and peak crystallization temperature increases with the increase in Sn % as well as with the heating rate. 相似文献
996.
The thermal decomposition behaviours of oxovanadium(IV)hydroxamate complexes of composition [VO(Q)2?n(HL1,2)n]: [VO(C9H6ON)(C6H4(OH)(CO)NHO)] (I), [VO(C6H4(OH)(CO)NHO)2] (II), [VO(C9H6ON)(C6H4(OH)(5-Cl)(CO)NHO)] (III), and [VO(C6H4(OH)(5-Cl)(CO)NHO)2] (IV) (where Q?=?C9H6NO? 8-hydroxyquinolinate ion; HL1?=?[C6H4(OH)CONHO]? salicylhydroxamate ion; HL2?=?[C6H3(OH)(5-Cl)CONHO]? 5-chlorosalicylhydroxamate ion; n?=?1 and 2), which are synthesised by the reactions of [VO(Q)2] with predetermined molar ratios of potassium salicylhydroxamate and potassium 5-chlorosalicylhydroxamate in THF?+?MeOH solvent medium, have been studied by TG and DTA techniques. Thermograms indicate that complexes (I) and (III) undergo single-step decomposition, while complexes (II) and (IV) decompose in two steps to yield VO(HL1,2) as the likely intermediate and VO2 as the ultimate product of decomposition. The formation of VO2 has been authenticated by IR and XRD studies. From the initial decomposition temperatures, the order of thermal stabilities for the complexes has been inferred as III?>?I > II?>?IV. 相似文献
997.
In this study, we have studied the effect of elements Ag, Cd, and Sn as chemical modifiers on some thermal transport properties (thermal conductivity, diffusivity, and specific heat per unit volume) of amorphous Se. Concurrent measurements of thermal transport properties such as effective thermal conductivity (??e), thermal diffusivity (??e), and specific heat per unit volume (??C v) are used at room temperature for twin pellets of pure Se- and Se-based binary Se98M2 (M?=?Ag, Cd, and Sn) alloys using transient plane source technique. We have also determined the thermal inertia I T using the experimental values of thermal conductivity and specific heat per unit volume for present amorphous alloys. The increasing sequence of measured thermal transport properties is also discussed. 相似文献
998.
Neeraj Sharma Meena Kumari Reena Sharma 《Journal of Thermal Analysis and Calorimetry》2012,107(1):225-229
The thermal decomposition behavior of oxovanadium(IV)hydroxamate complexes of composition [VO(acac)(C6H5C(O)NHO)] (I), [VO(C6H5C(O)NHO)2] (II), [VO(acac)(4-ClC6H4C(O)NHO)] (III), [VO(4-ClC6H4C(O)NHO)2] (IV) (where acac = (CH3COCHCOCH3
–) synthesized from the reactions of VO(acac)2 with equi- and bimolar amounts of potassium benzohydroxamate and potassium 4-chlorobenzohydroxamate in THF + MeOH solvent
medium has been studied by TG and DTA techniques. TG curves indicated that complexes I, II, and IV undergo decomposition in
single step to yield VO2 as the final residue, while complex III decomposes in two steps to yield VO(acac) as the likely intermediate and VO2 as the ultimate product of decomposition. The formation of VO2 has been authenticated by IR and XRD studies. From the initial decomposition temperatures, the order of thermal stability
for the complexes has been inferred as IV > I > III > II. 相似文献
999.
Reaction of dibutyltin dichloride, dimethyltin dichloride, and tributyltin chloride with ligands derived from thiosemicarbazone
and semicarbazone leads to the formation of a new series of organotin(IV) complexes of general formula R2SnCl2·L and R3SnCl·L (where L ligands derived from the condensation of thiosemicarbazide and semicarbazide with 4-hydroxy-3-methoxybenzaldehyde). The authenticity
of these ligands and their metal complexes have been established on the basis of elemental analysis, conductance measurements,
molecular weight determinations, infrared, 1H NMR, 13C NMR, 119Sn NMR, and UV spectral studies. These studies showed that the ligands coordinate to the metal atom in a bidentate. An octahedral
structure is proposed for the organotin(IV) complexes. The ligands and its metal complexes are screened for their antimicrobial
activities against some Gram-positive and Gram-negative bacteria, and fungus. The studies demonstrated that metalation can
increase the antimicrobial activity rather than the free ligands. 相似文献
1000.
Sonali Verma Barkha Srivastava Kusum Sharma Rahul Joshi Pushpa Pardasani R. T. Pardasani 《Research on Chemical Intermediates》2012,38(3-5):723-731
[4?+?2]-Photocycloadditions of benzo[b]thiophene-2,3-dione with electron-rich and electron-deficient alkenes have been described. Olefins preferentially add at both carbonyl groups to give the head-to-head [4?+?2] cycloadducts, i.e., dioxanes only. Comprehensive molecular orbital calculations at DFT-B3LYP level have been carried out to address the mechanism as well as regiochemical course of the reaction. 相似文献