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Nonlinear Dynamics - We investigate, numerically and analytically, the quantum mechanics of planar elastic pendulum in libration. The classical phase space of the system consists of both regular... 相似文献
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Molecular Diversity - We report here selective formation of functionalized 1,4-dihydropyridines (DHP), acridinediones and polyhydroquinolines in high yields using amine-functionalized graphene... 相似文献
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A single-step melt-quench in situ thermochemical reduction technique has been used to synthesize a new series of Au° nanoparticles embedded antimony glass–ceramic (K2O–B2O3–Sb2O3–ZnO) dichroic nanocomposites. X-ray and selected area electron diffractions manifest growth of Au° nanoparticles along (2 0 0) planes. The particle sizes obtained from X-ray diffraction patterns are found to vary in the range 4–21 nm. Dichroic behavior is attributed to the elliptical shape gold nanoparticles having aspect ratio 1.2, as observed from the transmission electron microscopy (TEM) images. The Au° nanoparticles exhibit surface plasmon resonance band (SPR) around 600 nm, which experiences red-shifts with increasing Au concentration. These nanocomposites when co-doped with Sm2O3 and excited at 949 nm, exhibit 2-fold intensification of 636 nm red emission transition (4G5/2 → 6H9/2) due to SPR induced local field enhancement of Au° nanoparticles and are promising materials for display applications. 相似文献
57.
Mallick A Haldar B Maiti S Bera SC Chattopadhyay N 《The journal of physical chemistry. B》2005,109(30):14675-14682
Photophysical properties of 3-acetyl-4-oxo-6,7-dihydro-12H-indolo[2,3-a]quinolizine (AODIQ), a bioactive molecule, has been investigated in well-characterized, monodispersed biomimicking nanocavities formed by sodium bis(2-ethylhexyl)sulfosuccinate (AOT) in heptane using steady-state and picosecond time resolved fluorescence and fluorescence anisotropy. The emission behavior of AODIQ is very much dependent upon the water/surfactant mole ratio (W), i.e., on the water pool size of the reverse micellar core. AODIQ exhibits a sharp decrease in fluorescence anisotropy with increasing W, implying that the overall motional restriction experienced by the molecule is decreased with increased hydration. Some of the depth-dependent relevant fluorescence parameters, namely, fluorescence maxima and fluorescence anisotropy (r), have been monitored for exploiting the distribution and microenvironment around the probe in the reverse micelles. Fluorescence spectral position and fluorescence quenching studies suggest that the probe does not penetrate into the reverse micellar core; rather it binds at the interfacial region. Quantitaive estimates of the micropolarity and microviscosity at the binding sites of the probe molecule have been determined as a function of W. 相似文献
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Reductive methylation of 1-carbomethoxy-4, 6-dimethoxynaphthalene in anhydrous ammonia gave 1-methyl-1-carbomethoxy-6-methoxy-1, 4-dihydronaphthalene in good yield. Metal ammonia reduction of the ketones 12 and 18 provided an expedient pathway for the synthesis of the ,β-unsaturated ketones 17 and 19 respectively. 相似文献
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The iron(II) complex of H2L (H2L=3, 14‐dimethyl‐4, 7, 10, 13‐tetraazahexadeca‐3,13‐diene‐2,15‐dione dioxime, Coord. Chem. Rev., 33, 87 (1980)) is oxidized by periodate very rapidly in the range pH 2.0–7.0, and the kinetics of the reaction has been followed by stopped‐flow spectrophotometry at 30°C and ionic strength I=0.20 mol L−1 (NaClO4). The reaction is found to follow a simple second‐order kinetics as −d/dt [FeII(H2L)2+]=k [FeII(H2L)2+] [I(VII)], giving [FeIII(L)]+ and IO3− as the final products. The reaction has been proposed to occur through a H‐bonded transition state formed probably between the protonated oxime group of the ligand and the oxygen atom on the periodate species, followed by an electron transfer from FeII centre to IVII in a rate‐determining step. The IVI species thus generated reacts in a fast step with another FeII complex. © 1999 John Wiley & Sons, Inc. Int J Chem Kinet 31: 23–28, 1999 相似文献
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A.K. Dhara S. Bhattacharya K. Krishan 《The European Physical Journal A - Hadrons and Nuclei》2000,7(2):209-217
The dynamics of fission has been formulated by generalising the asymptotic expansion of the Fokker-Planck equation in terms
of the strength of the fluctuations where the diffusion coefficients depend on the stochastic variables explicitly. The prescission
neutron multiplicities and mean kinetic energies of the evaporated neutrons have been calculated and compared with the respective
experimental data over a wide range of excitation energy and compound nuclear mass. The mean and the variance of the total
kinetic energies of the fission fragments have been calculated and compared with the experimental values.
Received: 8 September 1999 / Revised version: 22 November 1999 相似文献