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61.
Ravi P. Agarwal B. Kovacs D. O’Regan 《Journal of Applied Mathematics and Computing》2014,44(1-2):437-454
This paper investigates the existence of positive solutions for a sixth-order differential system with three variable parameters. Using a fixed point theorem and an operator spectral theorem we give some new existence results. 相似文献
62.
Muhammad Sulaiman Ali Thangamani Arumgam Ravi Subban 《Research on Chemical Intermediates》2017,43(10):5637-5664
Research on Chemical Intermediates - Eight new series of novel phenothiazine-based chalcone derivatives with various N-substituted rhodanines (10a–g to 17a–g) were synthesized by... 相似文献
63.
Yugandhar Kothapalli Ravi Kumar Puthukanoori Srinivasa Rao Alapati 《Tetrahedron letters》2012,53(15):1891-1893
An enantiospecific first total synthesis of metabolite 7a(S)-p-hydroxyphenopyrrozin 2, isolated from the cultured fungi Chromocleista sp. has been achieved starting from readily and abundantly available l-proline. The strategy of synthesis utilizes base mediated cyclization and base mediated oxygenation as the key steps. 相似文献
64.
65.
B. P. Nandeshwarappa D. B. Aruna Kumar M. N. Kumaraswamy Y. S. Ravi Kumar H. S. Bhojya Naik K. M. Mahadevan 《Phosphorus, sulfur, and silicon and the related elements》2013,188(7):1545-1556
A series of novel substituted thiopyrano[2,3-b]quinolines 4a–e , 5a–e , and 6a–e were prepared from substituted 3-formyl-2-mercapto quinolines 2a–e , on reaction with ethyl acetoacetate, diethyl malonate, and ethyl cyanoacetate 3a–c by microwave irradiation in the presence of piperidine. Synthesized compounds were evaluated for antimicrobial activities. Among the compounds tested, 7-chloro-2-oxo-2H-thiopyrano[2,3-b]quinoline-3-carbonitrile 6d and 7-nitro-2-oxo-2H-thiopyrano[2,3-b]quinoline-3-carbonitrile 6e were highly active against S. aureus and M. roseus. 相似文献
66.
Fadong Yan Tomoya Higashihara Ravi Mosurkal Lian Li Ke Yang Rudolf Faust 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(11):910-913
Self organization and redox behavior of a ferrocene containing triblock copolymer, poly(vinylferrocene)-block-poly(isobutylene)-block-poly(vinylferrocene), with narrow molecular weight distribution in solutions and in thin films were investigated. Dynamic light scattering studies of the block copolymer in dilute solutions indicated that the polymer chains aggregated at relatively low concentrations. The aggregations of polymer chains were observed in toluene, as well as in tetrahydrofuran at concentrations as low as 0.014 mg/mL and 0.0045 mg/mL, respectively. Thin films of the copolymer showed reversible single electron redox behavior, similar to that of ferrocene. Morphology and micro-phase separation of the copolymer was analyzed by transmission electron microscopy. 相似文献
67.
T. M. Pramod Kumar H. M. Umesh H. G. Shivakumar Valluru Ravi 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(6):583-589
A series of terbutaline sulphate drug incorporated polyvinyl alcohol (PVA) matrix films were produced by the solvent evaporation method. The effect of xanthan gum and plasticizers (propylene glycol and dibutyl phthalate) on the rate and amount of drug diffusion from PVA membrane across the hydrated cellophane membrane has been evaluated, using an open glass diffusion‐tube. The obtained films were clear, smooth and flexible having sufficient mechanical strength. The mechanical performance of the dry PVA films with xanthan gum and plasticizers were also ascertained. Polyvinyl alcohol‐xanthan gum blends showed a high rate of drug release compared to that of polyvinyl alcohol film alone. Among the two plasticizers employed, propylene glycol showed better permeability. Among different formulations studied, the formulation PVA/xanthan gum/propylene glycol (F7) was found to be an optimized composition for efficient transdermal delivery of the model drug, terbutaline sulphate. The mechanism of drug diffusion has been evaluated using the Peppas model. Stability studies carried out on polymer‐drug formulations revealed that the drug is stable at 40°C and 75% RH for a period of 6 weeks. 相似文献
68.
We have designed and synthesized a new ruthenium complex, [(5‐amino‐1,10‐phenanthroline)bis(4,4′‐dicarboxylic acid‐2,2′‐bipyridine)]ruthenium(II) by introducing two types of ligands, 5‐amino‐1,10‐phenanthroline and 4,4′‐dicarboxylic acid‐2,2′‐bipyridine. We investigated the electronic, spectroscopic, electrochemical, and photovoltaic properties of the Ru(II) complex. The short‐circuit current density and overall solar‐to‐electric energy conversion efficiency of photovoltaic cells made with this Ru(II) complex were found to be 8.9 mA/cm2 and 2.1%, respectively. A series of analogous Ru(II) complexes have also been synthesized and investigated to compare the effects of functional groups on various ligands. HOMO‐LUMO energies and molecular orbital surfaces have been investigated using semiempirical quantum chemical methods. 相似文献
69.
Afshan Banu D.E. Vasundhara Ravi S. Lamani I.A.M. Khazi Noor Shahina Begum 《Journal of Saudi Chemical Society》2013,17(2):211-217
The preparation of 2-(4-fluorobenzyl)-6-(4-methoxyphenyl)-5-morpholin-1-ylmethyl imidazo[2,1-b][1,3,4]thiadiazole via the intermediate 2-(4-fluorobenzyl)-6-(4-methoxyphenyl)Imidazo[2,1-b][1,3,4] thiadiazole is described. Elemental analysis, IR spectrum, 1H NMR and X-ray crystal structure analyses were carried out to determine the compositions and molecular structures of the two compounds. The crystal packing exhibits intermolecular C–H?O, C–H?N, C–H?F and π–π stacking interactions leading to the formation of the supramolecular network. 相似文献
70.
Die Yang Liang Wang Zuliang Chen Mallavarapu Megharaj Ravi Naidu 《Electroanalysis》2013,25(12):2637-2644
The bismuth‐coated electrode is known to be prone to errors caused by copper(II). This study investigates copper(II) interference at bismuth film electrode for the detection of lead(II) and cadmium(II). It was conducted using glassy carbon electrode, while the bismuth film was plated in situ simultaneously with the target metal ions at ? 1200 mV. Copper(II) presented in solution significantly reduced the sensitivity of the electrode, for example there was an approximately 70 % and 90 % decrease in peak signals for lead(II) and cadmium(II), respectively, at a 10‐fold molar excess of copper(II). The decrease in sensitivity was ascribed to the competition between copper and bismuth or the metal ions for surface active sites. Scanning electron microscopy (SEM) and energy dispersive X‐ray (EDX) analysis suggested a large decrease in the amount of bismuth nanoparticles formed on the electrode surface in the presence of copper(II) occurred, validating the competition between copper and bismuth ions for surface active sites. Recovery of the stripping signal of lead(II) and cadmium(II) was obtained by adding ferrocyanide ion to the solution. Finally, the proposed method was successfully applied to determine lead(II) and cadmium(II) in water samples and the method was validated by ICP‐MS technique. 相似文献