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31.
This paper presents the new digital watermarking algorithm based on the chaotic map. Data can easily be hidden in images by using the least significant bits. In the anticipated algorithm, the logistic map is employed for locating embedding positions of chaotic watermark generation and a novel watermarking scheme is proposed. Simulation results reveal that the proposed technique is feasible and watermarks are indiscernible. The results illustrate that mean of energy, correlation, contrast, and homogeneity analyses of the proposed algorithm are quite optimal. 相似文献
32.
Ali S. Ara T. Danish M. Shujah S. Slawin A. M. Z. 《Russian Journal of Coordination Chemistry》2019,45(12):889-898
Russian Journal of Coordination Chemistry - A series of six tin(IV) complexes [SnCl2(L) (I), Me2Sn(L) (II), Bu2Sn(L) (III), Ph2Sn(L) (IV), Oct2Sn(L) (V), BuSnCl(L) (VI)] derived from... 相似文献
33.
A. Shaukat Y. Saeed S. Nazir N. Ikram M. Tanveer 《Physica B: Condensed Matter》2009,404(21):3964-3972
Full-potential linearized augmented plane wave method (FP-LAPW) within density functional theory has been used to calculate structural, electronic and optical properties of Ca1−xSrxS, an alkali earth chalcogenide, with varying compositional parameter x in the range 0<x<1. Whereas the structural properties are discussed in terms of charge transfer between the two cations, calculated electronic band structure and density of states have been analyzed in terms of contribution from the S p, Ca d and Sr d states. Furthermore, we have calculated some optical properties such as real and imaginary parts of dielectric constant, ε(ω), and the calculated results have been discussed in comparison with the existing experimental data and other theoretical calculations. 相似文献
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Highly substituted indole derivatives bearing alkyl and aryl moieties can be prepared by Sc(OTf)(3)-catalyzed Friedel-Crafts alkenylation of 5-(arylamino)pent-3-yn-2-ones. In addition, a method for regioselective hydrochlorination of 5-(arylamino)pent-3-yn-2-ones mediated by SnCl(4) in moderate to good yields (up to 84%) has been developed. The resulting exclusive Z-selectivity of the C-Cl bond can be further exploited using cross C-N coupling reactions. 相似文献
36.
Adeel Arsalan Iqbal Ahmad Syed Abid Ali Kiran Qadeer Shaukat Mahmud Fozia Humayun Anwar Ejaz Beg 《国际化学动力学杂志》2020,52(3):207-217
Cyanocobalamin (B12) is a photosensitive vitamin, and its photodegradation to hydroxocobalamin (B12b) in liposomes has been investigated. The values of apparent first-order rate constants (kobs) for the photodegradation of B12 in liposomes (nine preparations) are in the range of (0.52-2.24) × 10–3 min–1, compared to 3.21 × 10–3 min–1 for B12 in aqueous solution (pH 5.0). The entrapment efficiency of B12 in liposomes is 26.4-38.8%. The values of kobs show a linear relation with phosphatidylcholine (PC) content in liposomes, indicating the influence of PC in inhibiting the rate of photolysis of B12. The value of the bimolecular rate constant for photochemical interaction of B12 and PC is 0.32 M–1 min–1, indicating the stabilizing effect of PC on the photolysis of B12. The ratio of B12 stabilization in liposomal preparations is in the range 2-6 compared to that of the unentrapped vitamin The stabilization of B12 is mediated by a photoinduced charge-transfer B12-PC complex that leads to the reduction of B12 to B12r, which is then oxidized to B12b that has low susceptibility to photolysis. The extent of stabilization of B12 probably depends on the degree of interaction between the two compounds under the reaction conditions, indicated by the loss of B12 fluorescence. 相似文献
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A mild, metal-free, and environmently benign iodine-promoted regioselective C-C and C-N bonds formation of N-protected indole derivatives giving 2,3'-biindoles 2 and 4-(1H-indol-2-yl)morpholines 4 is successfully demonstrated. Various bioactive 2,3'-biindoles and 4-(1H-indol-2-yl)morpholines, bearing electron-rich to moderately electron-poor substituents, can be prepared in moderate to good yields. 相似文献
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Schamel equation in an inhomogeneous magnetized sheared flow plasma with q-nonextensive trapped electrons 下载免费PDF全文
An investigation is carried out for understanding the properties of ion–acoustic(IA) solitary waves in an inhomogeneous magnetized electron-ion plasma with field-aligned sheared flow under the impact of q-nonextensive trapped electrons. The Schamel equation and its stationary solution in the form of solitary waves are obtained for this inhomogeneous plasma. It is shown that the amplitude of IA solitary waves increases with higher trapping efficiency(β), while the width remains almost the same. Further, it is found that the amplitude of the solitary waves decreases with enhanced normalized drift speed, shear flow parameter and the population of the energetic particles. The size of the nonlinear solitary structures is calculated to be a few hundred meters and it is pointed out that the present results are useful to understand the solar wind plasma. 相似文献