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The synthesis of 9- and 10-methylbenz[a]anthracenes by improved methods are described. These new procedures are simple and convenient, and provide the title compounds in good yields and high purity. 相似文献
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Haes AJ Zhao J Zou S Own CS Marks LD Schatz GC Van Duyne RP 《The journal of physical chemistry. B》2005,109(22):11158-11162
A novel method to produce solution-phase triangular silver nanoparticles is presented. Ag nanoparticles are prepared by nanosphere lithography and are subsequently released into solution. The resulting nanoparticles are asymmetrically functionalized to produce either single isolated nanoparticles or dimer pairs. The structural and optical properties of Ag nanoparticles have been characterized. Mie theory and the Discrete Dipole Approximation method (DDA) have been used to model and interpret the optical properties of the released Ag nanoparticles. 相似文献
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In this study, we explore the reactions of coordinated arenes, e.g., hydrogenation, nitration, and bromination, to prepare compounds which are not accessible from conventional organic synthesis. The reaction products formed from reactions with the coordinated and the uncoordinated arenes are compared. The polycyclic aromatic hydrocarbons (PAHs) employed for this study include phenanthrene, methyl- and acetyl-phenanthrene, and benz[a]anthracene (BA), The tricarbonylchromium group demonstrated various characteristics which influence the reactions in this work, such as an electronic effect to deactivate hydrogenation, a steric effect to exhibit, highly positional selective nitration, and a free radical mechanism to direct bromine to attack at the ring coordinated to tricarbonylchromium. 相似文献
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Riad AM Elminir HK Own HS Azzam YA 《Journal of photochemistry and photobiology. B, Biology》2008,90(2):95-104
This work presents the applicability of applying a fuzzy logic approach to the calculation of noontime erythemal UV irradiance for the plain areas of Egypt. When different combinations of data sets were examined from the test performance point of view, it was found that 91% of the whole series was estimated within a deviation of less than +/-10 mW/m(2), and 9% of these deviations lay within the range of +/-15 mW/m(2) to +/-25 mW/m(2). 相似文献
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Deprotonation, methylation, and air oxidation of polycyclic arenes coordinated to chromium(0), (η6-arene)Cr(CO)3, produced ring-methylated products with high selectivity and in good yield. This procedure gave 3-methylbenz[a]anthracene from (η6-benz[a]anthracene)Cr(CO)3, 3-methylphenanthrene from (η6-phenanthrene)Cr(CO)3, 2-acetyl-6-methylphenanthrene from (η6?2-acetylphenanthrene)Cr(CO)3, and 3,7,12-trimethylbenz[a]anthracene from (η6?7,12-dimethylbenz[a]anthracene)Cr(CO)3. 相似文献
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Elminir HK Own HS Azzam YA Riad AM 《Journal of photochemistry and photobiology. B, Biology》2008,90(3):198-206
The problem we address here describes the on-going research effort that takes place to shed light on the applicability of using artificial intelligence techniques to predict the local noon erythemal UV irradiance in the plain areas of Egypt. In light of this fact, we use the bootstrap aggregating (bagging) algorithm to improve the prediction accuracy reported by a multi-layer perceptron (MLP) network. The results showed that, the overall prediction accuracy for the MLP network was only 80.9%. When bagging algorithm is used, the accuracy reached 94.8%; an improvement of about 13.9% was achieved. These improvements demonstrate the efficiency of the bagging procedure, and may be used as a promising tool at least for the plain areas of Egypt. 相似文献
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一种确定固相反应机理函数的新方法——固态草酸镍(Ⅱ)二水合物脱水过程的非等温动力学 总被引:5,自引:0,他引:5
The dehydration of nickel(Ⅱ) oxalate dihydrate in solid state was investigated by TG-DTA techniques. On the basis of Coats-Redfern′s and Ozawa′s integral equations, the double extrapolate method was suggested, i.e.heating rate Φ and proportion weight loss of a sample α were extrapolated to zero, respectively. Using comparision EΦ→0 with Eα→0 the kinetic mechanism was concluded to be nuclear producing and growing process (n=1.5). The intergral function of the mechanism is [-ln(1-α)]1/1.5 and the corresponding kinetic parameters were determined. 相似文献
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Christopher S Own Arun K Subramanian Laurence D Marks 《Microscopy and microanalysis》2004,10(1):96-104
Kinematical and two-beam calculations have been conducted and are compared to experimental precession data for the large unit cell crystal La4Cu3MoO12. Precession electron diffraction intensities are found to exhibit approximate two-beam behavior and demonstrate clear advantages over conventional SADP intensities for use in structure solution. 相似文献
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Ali Kanso Hala S. Own 《Communications in Nonlinear Science & Numerical Simulation》2012,17(8):3287-3302
In this paper, we suggest a new steganographic spatial domain algorithm based on a single chaotic map. Unlike most existing steganographic algorithms, the proposed algorithm uses one chaotic map to determine the pixel position of the host color image, the channel (red, green or blue) and the bit position of the targeted value in which a sensitive information bit can be hidden. Furthermore, this algorithm can be regarded as a variable-sized embedding algorithm. Experimental results demonstrate that this algorithm can defeat many existing steganalytic attacks. In comparison with existing steganographic spatial domain based algorithms, the suggested algorithm is shown to have some advantages over existing ones, namely, larger key space and a higher level of security against some existing attacks. 相似文献
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