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1.
The photochemical synthesis of 12H-benzothiazolo [2,3-b]quinazolin-12-ones (4) by the irradiation of 2-thioquinazolinediones 1 and disulphide 5 are described. 相似文献
2.
Silija Padikkaparambil Zahira Yaakob Binitha N. Narayanan Resmi Ramakrishnan Suraja Viswanathan 《Journal of Sol-Gel Science and Technology》2012,63(1):108-115
In the present study, a novel method for the silver nanoparticle incorporation into TiO2 sol is reported which provides efficient dispersion of inserted metal in the calcined gel. Glucose mediated metal nanoparticle synthesis eliminates the additional steps for the introduction of dopant over the support. Ag nanoparticle acts as competent trapping centers preventing the recombination of electron?Chole pairs. Thus, in spite of the low UV intensity present in the sunlight, considerable enhancement in the catalytic efficiency was observed for the degradation of dye pollutants over nanosilver loaded TiO2. Transmission electron microscopic images display the well isolated nanoparticles of silver having uniform dimensions of less than 5?nm over the best system, 2?wt% nanosilver loaded TiO2, which is accountable for its effectiveness as a photocatalyst. Anatase is found to be the photocatalytic active phase, as evident from the X-ray diffraction studies. 相似文献
3.
We present a seventh order iterative method for solving systems of nonlinear equations. The algorithm is derivative free per full iteration. A comparison between the computational efficiencies of proposed technique and existing techniques of similar nature is made. It is shown that for large system the new method is more efficient. The performance is tested through numerical experimentation which also confirms the theoretical results. 相似文献
4.
Robust Stability Criteria for Uncertain Neutral Systems with Interval Time-Varying Delay 总被引:1,自引:0,他引:1
In this paper, we consider the problem of robust stability of a class of linear uncertain neutral systems with interval time-varying
delay under (i) nonlinear perturbations in state, and (ii) time-varying parametric uncertainties using Lyapunov-Krasovskii
approach. By constructing a candidate Lyapunov-Krasovskii (LK) functional, that takes into account the delay-range information
appropriately, less conservative robust stability criteria are proposed in terms of linear matrix inequalities (LMI) to compute
the maximum allowable bound for the delay-range within which the uncertain neutral system under consideration remains asymptotically
stable. The reduction in conservatism of the proposed stability criterion over recently reported results is attributed to
the fact that time-derivative of the LK functional is bounded tightly without neglecting any useful terms using a minimal
number of slack matrix variables. The analysis, subsequently, yields a stability condition in convex LMI framework, that can
be solved non-conservatively at boundary conditions using standard LMI solvers. The effectiveness of the proposed stability
criterion is demonstrated through standard numerical examples. 相似文献
5.
We present a new third order method for finding multiple roots of nonlinear equations based on the scheme for simple roots developed by Kou et al. [J. Kou, Y. Li, X. Wang, A family of fourth-order methods for solving non-linear equations, Appl. Math. Comput. 188 (2007) 1031-1036]. Further investigation gives rise to new third and fourth order families of methods which do not require second derivative. The fourth order family has optimal order, since it requires three evaluations per step, namely one evaluation of function and two evaluations of first derivative. The efficacy is tested on a number of relevant numerical problems. Computational results ascertain that the present methods are competitive with other similar robust methods. 相似文献
6.
K.C. Gowri SreedeviAjesh P. Thomas P.S. SaliniS. Ramakrishnan K.S. AnjuM.G. Derry Holaday M.L.P. Reddy 《Tetrahedron letters》2011,52(45):5995-5999
A two-step synthesis of 5,5-diaryldipyrromethanes in good yields is described. The adopted synthetic strategy can be used to tune the substituent at the meso-carbon very easily by choosing the Grignard reagent of interest. Further, the influence of the incorporation of various diaryl units at the meso-carbon atom in the inherent anion binding affinities of the dipyrromethanes through hydrogen bonding was discussed. 相似文献
7.
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9.
S. Senthilkumar M. Briget Mary V. Ramakrishnan 《Journal of Raman spectroscopy : JRS》2007,38(3):288-294
The vibrational assignments of the observed wavenumbers have been made by analyzing the infrared and Raman spectra of L ‐valinium picrate in the crystalline state at room temperature. L ‐Valinium acts as the cation of the crystal and the carbonyl CO group exists in the protonated form in it. Asymmetric deformation and symmetric deformation modes of the isopropyl group have been identified, indicating that the two CH3 groups are in different environments. The stretching and bending modes of the various functional groups have been shifted owing to the extensive intermolecular hydrogen bonding in the crystal. The symmetry of the picrate anion has not been modified in the crystal by the hydrogen bonding with the cation. Fermi resonance is also observed. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
10.
Jin‐Baek Kim Ramakrishnan Ganesan So Young Yoo Jae‐Hak Choi Sang Yup Lee 《Macromolecular rapid communications》2006,27(17):1442-1445
Summary: A simple lithographic process in conjunction with a novel biocompatible nonchemically amplified photoresist material was successfully used for cell patterning. UV light irradiation on selected regions of the nonchemically amplified resist film renders the exposed regions hydrophilic by the formation of carboxylic groups. Mouse fibroblast cells were found to be preferentially aligned and proliferated on the UV light exposed regions of the nonchemically amplified resist film where carboxylic groups were present.