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91.
We investigate the characteristics of time-delay systems in the presence of Gaussian noise. We show that the delay time embedded
in the time series of time-delay system with constant delay cannot be estimated in the presence noise for appropriate values
of noise intensity thereby forbidding any possibility of phase space reconstruction. We also demonstrate the existence of
complete synchronization between two independent identical time-delay systems driven by a common noise without explicitly
establishing any external coupling between them. 相似文献
92.
D.V. Senthilkumar M. Lakshmanan J. Kurths 《The European physical journal. Special topics》2008,161(1):35-44
Phase synchronization in unidirectionally coupled Ikeda time-delay systems
exhibiting non-phase-coherent hyperchaotic attractors of complex topology with
highly interwoven trajectories is studied. It is shown that in this set of
coupled systems phase synchronization (PS)does exist in a range of the
coupling strength which is preceded by a transition regime (approximate PS)and
a nonsynchronous regime. However, exact generalized synchronization does not seem
to occur in the coupled Ikeda systems (for the range of parameters we have
studied)even for large coupling strength, in contrast to our earlier studies in
coupled piecewise-linear and Mackey-Glass systems [27,28].
The above transitions are characterized in terms of recurrence based indices,
namely generalized autocorrelation function P(t), correlation of probability
of recurrence (CPR), joint probability of recurrence (JPR)and similarity of
probability of recurrence (SPR). The existence of phase synchronization is also
further confirmed by typical transitions in the Lyapunov exponents of the
coupled Ikeda time-delay systems and also using the concept of localized sets. 相似文献
93.
Post growth multilayer instabilities of a certain periodic Gd2O3/SiO2 multilayer systems have been investigated using scanning probe force-distance spectroscopy and optical spectrophotometric techniques. In the present work, we have noticed a strong correlation between the force spectroscopic results and the spectral properties of multilayer thin films, although measurement techniques and operating principles are quite different. From the experimental analysis, it was quite evident that the instability process, which starts during the nucleation and growth stage in thin films, continues to persist at a much longer time scale under post growth conditions. During this study it has been noticed that the elastic properties of the constituent thin films, the layer geometry and the bilayer thickness have strong correlation in trickling the multilayer instabilities. Such aspects also have strong interconnections with the morphological and viscoelastic changes. It is also noticed that most of the instabilities results cannot only be explained through elastic nature of the material alone. Instead, total number of layers, the layer structures, morphological changes, corresponding stiffness and the adhesion properties of the multilayer contribute substantially to these phenomena. 相似文献
94.
A facile synthesis of some diketones that fit into a steroid motif was achieved from Mannich salts and cyclic ketones under microwave irradiation. 相似文献
95.
96.
Natarajan Senthilkumar Hak-Su Kang Dae-Won Park Youngson Choe 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(5):484-490
In this study, polymeric nanocomposites of poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) (PEDOT:PSS) and functionalized multi-walled carbon nanotubes (MWCNTs) were spin coated on a pre-patterned ITO glass and used as a hole conducting layer in organic photovoltaic cells. The multi-layered ITO/MWCNT-PEDOT:PSS/CuPc/C60/Al devices were fabricated to investigate the current density-voltage characteristics and power conversion efficiency. The power conversion efficiency obtained from the device with a concentration of 1.0 wt% MWCNT in the PEDOT:PSS layer was increased twice as those adopted from device without MWCNT doping in the PEDOT:PSS layer and current density-voltage characteristics was also improved well with incorporation of MWCNTs. 相似文献
97.
Senthilkumar C. Krishnan A. S. Solomon A. Brusly 《Journal of Thermal Analysis and Calorimetry》2020,139(2):963-973
Journal of Thermal Analysis and Calorimetry - The heat transfer characteristics of a thin porous copper-coated wickless heat pipe using R134a as a working fluid is investigated and is... 相似文献
98.
Microwave-mediated three-component condensation of 4-aryl-4-oxobutanoates with ammonium formate furnishes 3-methylidene-5-phenyl-2,3-dihydropyrrolidones
in good yield within 2 min. The pyrrolidone products were characterized on the basis of spectral data and X-ray crystal structure
analysis. The reaction is found to be general and a variation in the ester and aryl moieties is possible. However, when alkylammonium
formate is used only amide products are formed 相似文献
99.
In this study, we report the observation of memory effect in TiO2–GO nanocomposite films. Electrical properties of the prepared Al/TiO2–GO composite/ITO devices have shown stable and reproducible bipolar resistive switching behavior. The TiO2–GO composite films were prepared using solution method by spin coating technique. Observed results have shown that the inclusion of GO in the TiO2 matrix have exhibited a significant role in the resistive switching mechanism. The device has exhibited an excellent memory characteristic with low operating voltages, good endurance up to 105 cycles and long retention time more than 5×103 s. 相似文献
100.
Quantum chemical studies on tautomerism of barbituric acid in gas phase and in solution 总被引:2,自引:0,他引:2
Ab initoand density functional theory (DFT) methods were used to study the tautomers of barbituric acid in the gas phase and in a polar medium. In the gas phase, the tautomers were optimized at the HF/6-31G*, MP2/6-31G*and B3LYP/6-31G*, B3PW91/6-31G*levels of theory. The self-consistent reaction field theory (SCRF) at the HF/6-31G*level of theory has been used to optimize the tautomers in a polar medium. The relative stability of the tautomers was compared in the gaseous and polar mediums. The ability of maximum hardness principle to predict the stable tautomer has been studied. The 13C-NMR chemical shift for carbon atoms in the tautomers was calculated and the results are discussed. 相似文献