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141.
Simultaneous velocity and temperature measurements in gaseous flow fields using the VENOM technique 总被引:1,自引:0,他引:1
We present an initial demonstration of simultaneous velocity and temperature mapping in gaseous flow fields using a new nitric oxide planar laser-induced fluorescence-based method. The vibrationally excited NO monitoring (VENOM) technique is an extension of two-component velocimetry using vibrationally excited NO generated from the photodissociation of seeded NO(2) [Appl. Opt. 48, 4414 (2009)], where the two sequential fluorescence images are obtained probing two different rotational states to provide both velocity and temperature maps. Comparisons to computational fluid dynamics simulations show that the initial VENOM measurements provide good velocity and temperature maps in the relatively high-density regions of the flow, where the rms uncertainties are approximately 5% for velocity and 9% for temperature. 相似文献
142.
Large area fabrication of metal alloy nanoparticles with tunable surface plasmon resonances on low-cost substrates is reported. A UV excimer laser was used to anneal 5 nm thick Ag Au bilayer films deposited with different composition ratios to create alloy nanoparticles. These engineered surfaces are used to investigate how the wavelength of the surface plasmon resonance affects the optical detection capability of chemical species by surface-enhanced Raman spectroscopy. 相似文献
143.
K.D.G.I. Jayawardena Charles OpokuJames Fryar S. Ravi P. SilvaSimon J. Henley 《Applied Surface Science》2011,257(12):5274-5277
The synthesis of ZnO nanocrystals is reported using a hydrothermal chemical growth technique combined with 248 nm nanosecond excimer laser heating at fluences in the range 0-390 mJ cm−2. The effect of laser heating in controlling the morphology of the nanocrystals is investigated using optical spectroscopy and electron microscopy characterization. Laser heating is shown to allow control of the crystal morphology from nanoparticles to nanorods as well as to modify the size distributions. The results indicate that not only does the laser accelerate the growth of nanocrystals, but can also produce crystals with a narrow size distribution possibly via photothermal size selection. An initial study of electrical conduction properties of ZnO nanocrystal thin films is also discussed. 相似文献
144.
N.E. Rajeevan Ravi KumarD.K. Shukla R.J. ChoudharyP. Thakur A.K. SinghS. Patnaik S.K. AroraI.V. Shvets P.P. Pradyumnan 《Journal of magnetism and magnetic materials》2011,323(13):1760-1765
Thin films of BixCo2−xMnO4 (x=0, 0.1 and 0.3) were grown on quartz, LaAlO3 (LAO) and YBa2Cu3O7 (YBCO) buffer layer coated LAO substrates by pulsed laser deposition (PLD). X-ray diffraction (XRD) and Raman scattering measurements showed that the thin films exhibit single phase polycrystalline cubic spinel structure on all the substrates. Near edge X-ray absorption fine structure (NEXAFS) studies confirmed the octahedral occupancy of the substituted Bi3+ ions. Temperature dependent zero-field cooled (ZFC) magnetization measurements show the ferrimagnetic (FM) behavior (TC∼186 K) and magnetization undergoes a crossover from positive to negative, owing to the opposite contributions of magnetic moments from Co and Mn ions. A weak ferroelectric property exhibited by the films above room temperature was evidenced through the capacitance-voltage (C-V) and dielectric measurements. Magnetoelectric coupling was found to be maximum just below FM-TC. 相似文献
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Madhav S. Mane Ravi S. Balaskar Sandip N. Gavade Pramod N. Pabrekar Murlidhar S. Shingare Dhananjay V. Mane 《中国化学快报》2011,22(9):1039-1042
The regiospecific oxidation of alkyl group of both sterically hindered and unhindered aromatic amine to corresponding carbonyl compound was done in aq. medium by using DDQ. The optimized reaction protocol was found to be most simple, high yielding and novel method for oxidation of alkyl group of aromatic amine in to its carbonyl compound. 相似文献
149.
Said R. Grace Ravi P. Agarwal Martin Bohner Donal O’Regan 《Communications in Nonlinear Science & Numerical Simulation》2009,14(8):3463-3471
We establish some new criteria for the oscillation of second-order nonlinear dynamic equations on a time scale. We study the case of strongly superlinear and the case of strongly sublinear equations subject to various conditions. 相似文献
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