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141.
The present contribution reports a detailed photophysical study of a simple salicylic acid derivative viz., 3,5,6-Trichlorosalicylic
acid (TCSA) based on steady state absorption, emission and time-resolved emission spectroscopy. Anomalous “dual” emission
coupled with a large Stokes shift and negligible solvent polarity dependence marks the spectroscopic signature for Excited
State Intramolecular Proton Transfer (ESIPT) reaction. Variation of medium polarity and pH of the medium have been implemented
as fruitful tools to decipher the photophysics of TCSA. Quantum chemical calculation by ab initio Hartree-Fock and Density Functional Theory methods yields consistent results to follow experimental findings with distinct
illustration of the inoperativeness of GSIPT reaction as well as occurrence of ESIPT process. A rigorous comparison of our
experimental and theoretical measurements of TCSA with the parent compound salicylic acid, 5-chlorosalicylic acid and 3,5-dichlorosalicylic
acid reveals the impact of chlorine substitution on the photophysics of the studied molecular systems with simultaneous exploration
of the complexities induced in TCSA with respect to salicylic acid. 相似文献
142.
In this paper, a high-order nonlinear continuous integral-derivative observer is presented based on finite-time stability and singular perturbation technique. Not only the proposed integral-derivative observer can obtain the multiple integrals of a signal, but also the derivatives can be estimated. Conditions are given ensuring finite-time stability for the presented integral-derivative observer, and the stability and robustness in time domain are analyzed. The merits of the presented integral-derivative observer include its synchronous estimation of integrals and derivatives, finite-time stability, ease of parameters selection, sufficient stochastic noises rejection and almost no drift phenomenon. The theoretical results are confirmed by computational analysis and simulations. 相似文献
143.
Prabir Nandi Ajaya Bhattarai Bijan Das 《Journal of Polymer Science.Polymer Physics》2007,45(14):1765-1770
Precise measurements on the viscosities of the solutions of sodium carboxymethylcellulose in water and in two acetonitrile–water mixtures containing 10 and 20 vol % of acetonitrile have been reported at 35, 40 and 50 °C. Isoionic dilutions were performed with the total ionic strengths of the solutions maintained with sodium chloride at ~4.20 × 10?4 and 1.45 × 10?3 mol dm?3 of NaCl to obtain the intrinsic viscosities. The Huggins constants were also obtained from the experimental results. The influences of the medium, the temperature, and the total ionic strength on the intrinsic viscosities as well as on the Huggins constants have been interpreted from the points of view of the solvodynamic and thermodynamic interactions prevailing in the polyelectrolyte solution under investigation. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1765–1770, 2007 相似文献
144.
The electrical conductances of the solutions of sodium bromide (NaBr) and sodium tetraphenylborate (NaBPh4) in 2-ethoxyethanol + water mixed solvent media containing 0.25, 0.50 and 0.75 mass fractions of 2-ethoxyethanol (w1) have been reported at 308.15, 313.15, 318.15, and 323.15 K. The conductance data have been analyzed by the 1978 Fuoss conductance–concentration equation in terms of the limiting molar conductance (Λ0), the association constant (KA) and the association diameter (R). Of the two electrolytes investigated here, sodium bromide exists essentially in the form of free ions in aqueous 2-ethoxyethanol solutions over the entire temperature range investigated. However, slight ionic association was observed for sodium tetraphenylborate—the extent of which increases with increasing amount of 2-ethoxyethanol in the present mixed solvent media. The solvations of the bromide ion and of the sodium ion were found to be gradually weakened as the 2-ethoxyethanol content of the medium increases. Furthermore, the limiting molar conductivity values of the two electrolytes increase as the temperature increases in all 2-ethoxyethanol + water mixtures which have been described by polynomial equations. 相似文献
145.
We present a controllability result for a second order dynamic system and its application to global optimization in the context of multi-criteria problems. In particular, we address the issue of reaching points on nonconvex regions of Pareto fronts. To cite this article: B. Mohammadi, P. Redont, C. R. Acad. Sci. Paris, Ser. I 347 (2009). 相似文献
146.
Benjamin Ivorra Bijan Mohammadi Angel Manuel Ramos 《Journal of Global Optimization》2009,43(2-3):415-427
This paper focuses on the application of an original global optimization algorithm, based on the hybridization between a genetic algorithm and a semi-deterministic algorithm, for the resolution of various constrained optimization problems for realistic credit portfolios. Results are analyzed from a financial point of view in order to confirm their relevance. 相似文献
147.
Bijan Saha 《International Journal of Theoretical Physics》2006,45(5):952-964
We consider a self consistent system of Bianchi type-I (BI) gravitational field and a binary mixture of perfect fluid and dark energy. The perfect fluid is taken to be the one obeying the usual equation of state, i.e., p = ξε, with ζ∉[0, 1] whereas, the dark energy is considered to be obeying a quintessence-like equation of state. The modification of the ordinary quintessence lies in the fact that its pressure becomes positive if the (dark) energy density exceeds some critical value. Exact solutions to the corresponding Einstein equations are obtained. The model in consideration gives rise to a Universe which is spatially finite. Depending on the choice of problem parameters the Universe is either close with a space-time singularity, or an open one which is oscillatory, regular and infinite in time.
PACS numbers: 04.20.Ha, 03.65.Pm, 04.20.Jb 相似文献
148.
Precise measurements on the electrical conductivity of sodium polystyrenesulfonate in acetonitrile–water-mixed solvent media
containing 20 and 40 vol.% of acetonitrile at 308.15, 313.15, and 318.15 K are reported. The mobility of the polyelectrolyte
solute was found to be influenced by the polyelectrolyte concentration, the relative permittivity of the medium, and the temperature.
The Manning counterion condensation theory for salt-free polyelectrolyte solution failed to describe the experimental results.
The data have, therefore, been analyzed on the basis of a new model for semidilute polyelectrolyte conductivity which takes
into account the scaling arguments to obtain the fractions of uncondensed counterions which were found to depend on the polyelectrolyte
concentration. The effects of the temperature and the relative permittivity of the medium on the equivalent conductivity as
well as on the fraction of uncondensed counterions have also been discussed. 相似文献
149.
Bijan Saha 《Central European Journal of Physics》2010,8(6):920-923
Different characteristics of matter influencing the evolution of the uUniverse haves been simulated by means of a nonlinear
spinor field. We have considered two cases where the spinor field nonlinearity occurs either as a result of self-action or
due to the interaction with a scalar field. 相似文献
150.
Bijan Taeri 《Journal of Applied Mathematics and Computing》2006,20(1-2):75-96
Letm, n be positive integers. We denote byR(m, n) (respectivelyP(m, n)) the class of all groupsG such that, for everyn subsetsX 1, X2, . . .,X n of sizem ofG there exits a non-identity permutation σ such that $X_1 X_2 ...X_n \cap X_{\sigma (1)} X_{\sigma (2)} ...X_{\sigma (n)} \ne \not 0$ (respectively X1X2 . . .X n = Xσ(1)X{σ(2)} . . . X{gs(n)}). Let G be a non-abelian group. In this paper we prove that
- G ∈ P(2,3) if and only ifG isomorphic to S3, whereS n is the symmetric group onn letters.
- G ∈ R(2, 2) if and only if¦G¦ ≤ 8.
- IfG is finite, thenG ∈ R(3, 2) if and only if¦G¦ ≤ 14 orG is isomorphic to one of the following: SmallGroup(16,i), i ∈ {3, 4, 6, 11, 12, 13}, SmallGroup(32,49), SmallGroup(32, 50), where SmallGroup(m, n) is the nth group of orderm in the GAP [13] library.