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61.
Singh S Tripathi SK Saini GS 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,69(2):619-623
Infrared absorption spectra of copper phthalocyanine in KBr pellet and pyridine solution in 400-1625 and 2900-3200 cm(-1)regions are reported. In the IR spectra of solid sample, presence of weak bands, which are forbidden according to the selection rules of D4h point group, is explained on the basis of distortion in the copper phthalocyanine molecule caused by the crystal packing effects. Observation of a new band at 1511 cm(-1) and change in intensity of some other bands in pyridine are interpreted on the basis of coordination of the solvent molecule with the central copper ion. 相似文献
62.
We have developed a number of new anion exchange stationary phases based on synthesis of hyperbranched condensation polymers prepared in situ on surface sulfonated wide pore, low surface area ethylvinylbenzene-divinylbenzene substrate beads. These new stationary phases are synthesized by exposing the substrate beads to a mixture containing one of several different diepoxides and methyl amine followed by exposure in an alternating fashion to diepoxide and then methyl amine in a repetitive manner. With each cycle of reaction with first diepoxide and then methyl amine, the capacity of the stationary phase doubles, allowing for the synthesis of high-capacity materials. These new phases are stable to hydrolysis in concentrated acid and base. They exhibit exceptionally low levels of hydrophobic interaction with anionic species commonly of interest in the analysis of environmental samples. 相似文献
63.
Comparative study on different carbon nanotube materials in terms of transparent conductive coatings 总被引:1,自引:0,他引:1
Li Z Kandel HR Dervishi E Saini V Xu Y Biris AR Lupu D Salamo GJ Biris AS 《Langmuir : the ACS journal of surfaces and colloids》2008,24(6):2655-2662
We compared conductive transparent carbon nanotube coatings on glass substrates made of differently produced single-wall (SWNT), double-wall, and multiwall carbon nanotubes. The airbrushing approach and the vacuum filtration method were utilized for the fabrication of carbon nanotube films. The optoelectronic performance of the carbon nanotube film was found to strongly depend on many effects including the ratio of metallic-to-semiconducting tubes, dispersion, length, diameter, chirality, wall number, structural defects, and the properties of substrates. The electronic transportability and optical properties of the SWNT network can be significantly altered by chemical doping with thionyl chloride. Hall effect measurements revealed that all of these thin carbon nanotube films are of p-type probably due to the acid reflux-based purification and atmospheric impurities. The competition between variable-range hoping and fluctuation-assisted tunneling in the functionized carbon nanotube system could lead to a crossover behavior in the temperature dependence of the network resistance. 相似文献
64.
Sanz D Claramunt RM Saini A Kumar V Aggarwal R Singh SP Alkorta I Elguero J 《Magnetic resonance in chemistry : MRC》2007,45(6):513-517
Multinuclear magnetic resonance spectroscopy together with GIAO-DFT calculations allowed establishment of the structure of the products obtained by condensation of 3(5)-amino-4-phenyl-1H-pyrazole and beta-dicarbonyl compounds bearing a trifluoromethyl group. They are 3-phenyl-5-(R)-7-trifluoromethylpyrazolo[1,5-a]pyrimidines. 相似文献
65.
66.
A simple genetic algorithm is implemented to perform multi parameter optimization of Raman Fiber Amplifier for 100 channel S band dense wavelength division multiplexed system at 25 GHz interval. A cost effective system using single Raman pump is investigated aiming at maximum average gain. The single counter propagating pump is optimized to frequency of 211.528 THz and 652.93 mW power level with optimum Raman fiber length of 44.064 Km. There is evidence to show that the optimum solution presents a small gain variation (less than 3 dB) over an effective bandwidth covering 197–199.475 THz. The optimized configuration enabled an adequate system performance in terms of acceptable Q-factor (19.52 dB) and BER (1.46 × 10−21). 相似文献
67.
Saini R Boland S Kataeva O Schmidt AW Kurzchalia TV Knölker HJ 《Organic & biomolecular chemistry》2012,10(21):4159-4163
A stereoselective synthesis of (25S)-Δ(1)-, (25S)-Δ(1,4)-, (25S)-Δ(1,7)-, (25S)-Δ(8(14))-, (25S)-Δ(4,6,8(14))-dafachronic acid, methyl (25S)-Δ(1,4)-dafachronate and (25S)-5α-hydroxy-3,6-dioxocholest-7-en-26-oic acid is described. (25S)-Δ(1,4)-Dafachronic acid and its methyl ester are natural products isolated from corals and have been obtained by synthesis for the first time. (25S)-5α-Hydroxy-3,6-dioxocholest-7-en-26-oic acid represents a promising synthetic precursor for cytotoxic marine steroids. 相似文献
68.
The propagation of elastic waves is studied in a porous solid saturated with two immiscible viscous fluids.The propagation of three longitudinal waves is represented through three scalar potential functions.The lone transverse wave is presented by a vector potential function.The displacements of particles in different phases of the aggregate are defined in terms of these potential functions.It is shown that there exist three longitudinal waves and one transverse wave.The phenomena of reflection and refraction due to longitudinal and transverse waves at a plane interface between an elastic solid half-space and a porous solid half-space saturated with two immiscible viscous fluids are investigated.For the presence of viscosity in pore-fluids,the waves refracted to the porous medium attenuate in the direction normal to the interface.The ratios of the amplitudes of the reflected and refracted waves to that of the incident wave are calculated as a nonsingular system of linear algebraic equations.These amplitude ratios are used to further calculate the shares of different scattered waves in the energy of the incident wave.The modulus of the amplitude and the energy ratios with the angle of incidence are computed for a particular numerical model.The conservation of the energy across the interface is verified.The effects of variations in non-wet saturation of pores and frequencies on the energy partition are depicted graphically and discussed. 相似文献
69.
The interaction of a series of halophenols with sodium dodecyl sulphate and hexadecyltrimethylammonium bromide micelles was studied by different techniques (high-performance liquid chromatography, apparent acidity constant, spectral shift). The contributions of the halogens to the free energy of transfer from water to micelles are calculted. Correlations between the free energy of transfer for water/micellar solutions and for the classical octanol/water system are good. The application of micellar systems in chromatography and acid-base titrations is verified. 相似文献
70.
A. Chatterjee S. Kailas S. Saini S. K. Gupta M. K. Mehta 《Zeitschrift für Physik A Hadrons and Nuclei》1984,317(2):209-213
The absolute differential cross sections for the40Ca(α,α)40Ca reaction have been measured in the bombarding energy range from 4.33 to 5.68 MeV at the four laboratory angles 85°, 125°, 141° and 165°. An analysis of the data using multilevelR matrix theory has provided the spin-parities and widths of 29 levels in the compound nucleus44Ti. A comparison has been made with the levels deduced from the (α,γ) reaction and existing theoretical calculations of44Ti levels. 相似文献