13,510 research outputs found

    On two new species of Dermaptera from India (Dermaptera)

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    A sub-Doppler resolution double resonance molecular beam infrared spectrometer operating at chemically relevant energies (~2 eV)

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    A molecular beam spectrometer capable of achieving sub-Doppler resolution at 2 eV (~18 000 cm^–1) of vibrational excitation is described and its performance demonstrated using the CH stretch chromophore of HCN. Two high finesse resonant power-buildup cavities are used to excite the molecules using a sequential double resonance technique. A v = 0-->2 transition is first saturated using a 1.5 µm color center laser, whereupon a fraction of the molecules is further excited to the v = 6 level using an amplitude modulated Ti:Al2O3 laser. The energy absorbed by the molecules is detected downstream of both excitation points by a cryogenically cooled bolometer using phase sensitive detection. A resolution of approximately 15 MHz (i.e., three parts in 10^8) is demonstrated by recording a rotational line in the v = 6 manifold of HCN. Scan speeds of up to several cm^–1/h were obtained, with signal-to-noise ratios in excess of 100. The high signal-to-noise ratio and a dynamic range of 6×10^4 means that future experiments to study statistical intramolecular vibrational energy redistribution in small molecules and unimolecular isomerizations can be attempted. We would also like to point out that, with improved metrology in laser wavelengths, this instrument can also be used to provide improved secondary frequency standards based upon the rovibrational spectra of molecules

    Effect of Thermal Annealing on Boron Diffusion, Micro-structural, Electrical and Magnetic properties of Laser Ablated CoFeB Thin Films

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    We report on Boron diffusion and subsequent crystallization of Co40_{40}Fe40_{40}B20_{20} (CoFeB) thin films on SiO2_2/Si(001) substrate using pulsed laser deposition. Secondary ion mass spectroscopy reveals Boron diffusion at the interface in both amorphous and crystalline phase of CoFeB. High-resolution transmission electron microscopy reveals a small fraction of nano-crystallites embedded in the amorphous matrix of CoFeB. However, annealing at 400∘^\circC results in crystallization of CoFe with \textit{bcc} structure along (110) orientation. As-deposited films are non-metallic in nature with the coercivity (Hc_c) of 5Oe while the films annealed at 400∘^\circC are metallic with a Hc_c of 135Oe.Comment: 16 pages, 6 figure

    Measurement of particulate pollution in Jabalpur city during Diwali festival

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    The ambient air quality monitoring network involves measurement of number of air pollutant. A variety of method exist to measure particular matter in air

    Orthogonality properties of the Hermite and related polynomials

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    AbstractThe authors present a general method of operational nature with a view to investigating the orthogonality properties of several different families of the Hermite and related polynomials. In particular, the classical Hermite polynomials and some of their higher-order and multi-index generalizations are considered here

    On the smoothness of multi-M2 brane horizons

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    We calculate the degree of horizon smoothness of multi- M2M2-brane solution with branes along a common axis. We find that the metric is generically only thrice continuously differentiable at any of the horizons. The four-form field strength is found to be only twice continuously differentiable. We work with Gaussian null-like co-ordinates which are obtained by solving geodesic equations for multi-M2M2 brane geometry. We also find different, exact co-ordinate transformations which take the metric from isotropic co-ordinates to co-ordinates in which metric is thrice differentiable at the horizon. Both methods give the same result that the multi-M2M2 brane metric is only thrice continuously differentiable at the horizon.Comment: 24 pages, reference added, modified equation for non-singularity of metri
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