218 research outputs found

    Analysis of the inversion monitoring capabilities of a monostatic acoustic radar in complex terrain

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    A qualitative interpretation of the records from a monostatic acoustic radar is presented. This is achieved with the aid of airplane, helicopter, and rawinsonde temperature soundings. The diurnal structure of a mountain valley circulation pattern is studied with the use of two acoustic radars, one located in the valley and one on the downwind ridge. The monostatic acoustic radar was found to be sufficiently accurate in locating the heights of the inversions and the mixed layer depth to warrant use by industry even in complex terrain

    Charged particle concepts for fog dispersion

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    Charged particle techniques hold promise for dispersing warm fog in the terminal area of commercial airports. This report focuses on features of the charged particle technique which require further study. The basic physical principles of the technique and the major verification experiments carried out in the past are described. The fundamentals of the nozzle operation are given. The nozzle characteristics and the theory of particle charging in the nozzle are discussed, including information from extensive literature on electrostatic precipitation relative to environmental pollution control and a description of some preliminary reported analyses on the jet characteristics and interaction with neighboring jets. The equation governing the transfer of water substances and of electrical charge is given together with a brief description of several semi-empirical, mathematical expressions necessary for the governing equations. The necessary ingredients of a field experiment to verify the system once a prototype is built are described

    Quasi-Orthogonality of Some Hypergeometric and qq-Hypergeometric Polynomials

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    We show how to obtain linear combinations of polynomials in an orthogonal sequence {Pn}n≥0\{P_n\}_{n\geq 0}, such as Qn,k(x)=∑i=0kan,iPn−i(x)Q_{n,k}(x)=\sum\limits_{i=0}^k a_{n,i}P_{n-i}(x), an,0an,k≠0a_{n,0}a_{n,k}\neq0, that characterize quasi-orthogonal polynomials of order k≤n−1k\le n-1. The polynomials in the sequence {Qn,k}n≥0\{Q_{n,k}\}_{n\geq 0} are obtained from PnP_{n}, by making use of parameter shifts. We use an algorithmic approach to find these linear combinations for each family applicable and these equations are used to prove quasi-orthogonality of order kk. We also determine the location of the extreme zeros of the quasi-orthogonal polynomials with respect to the end points of the interval of orthogonality of the sequence {Pn}n≥0\{P_n\}_{n\geq 0}, where possible

    A comparative study of super- and highly-deformed bands in the A ~ 60 mass region

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    Super- and highly-deformed rotational bands in the A ~ 60 mass region are studied within cranked relativistic mean field theory and the configuration-dependent shell-correction approach based on the cranked Nilsson potential. Both approaches describe the experimental data well. Low values of the dynamic moments of inertia J^(2) compared with the kinematic moments of inertia J^(1) seen both in experiment and in calculations at high rotational frequencies indicate the high energy cost to build the states at high spin and reflect the limited angular momentum content in these configurations.Comment: 11 pages, 4 PostScript figures, Latex, uses 'epsf', submitted to Phys. Lett.

    Time-odd mean fields in the rotating frame: microscopic nature of nuclear magnetism

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    The microscopic role of nuclear magnetism in rotating frame is investigated for the first time in the framework of the cranked relativistic mean field theory. It is shown that nuclear magnetism modifies the expectation values of single-particle spin, orbital and total angular momenta along the rotational axis effectively creating additional angular momentum. This effect leads to the increase of kinematic and dynamic moments of inertia at given rotational frequency and has an impact on effective alignments.Comment: 16 pages, 4 figures, submitted to Physical Review

    Proof of two conjectures of Z.-W. Sun on congruences for Franel numbers

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    For all nonnegative integers n, the Franel numbers are defined as fn=∑k=0n(nk)3. f_n=\sum_{k=0}^n {n\choose k}^3. We confirm two conjectures of Z.-W. Sun on congruences for Franel numbers: \sum_{k=0}^{n-1}(3k+2)(-1)^k f_k &\equiv 0 \pmod{2n^2}, \sum_{k=0}^{p-1}(3k+2)(-1)^k f_k &\equiv 2p^2 (2^p-1)^2 \pmod{p^5}, where n is a positive integer and p>3 is a prime.Comment: 8 pages, minor changes, to appear in Integral Transforms Spec. Func

    Phosphine Oxide Porous Organic Polymers Incorporating Cobalt(II) Ions: Synthesis, Characterization, and Investigation of H2Production

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    Suitably functionalized porous matrices represent versatile platforms to support well-dispersed catalytic centers. In the present study, porous organic polymers (POPs) containing phosphine oxide groups were fabricated to bind transition metals and to be investigated for potential electrocatalytic applications. Cross-linking of mono- and di-phosphine monomers with multiple phenyl substituents was subject to the Friedel-Crafts (F-C) reaction and the oxidation process, which generated phosphine oxide porous polymers with pore capacity up to 0.92 cm3/g and a surface area of about 990 m2/g. The formation of the R3P·BH3 borohydride adduct during synthesis allows to extend the library of phosphine-based monomeric entities when using FeCl3. The porous polymers were loaded with 0.8-4.2 w/w % of cobalt(II) and behaved as hydrogen evolution reaction (HER) catalysts with a Faradaic efficiency of up to 95% (5.81 × 10-5 mol H2 per 11.76 C) and a stable current density during repeated controlled potential experiments (CPE), even though with high overpotentials (0.53-0.68 V to reach a current density of 1 mA·cm-2). These studies open the way to the effectiveness of tailored phosphine oxide POPs produced through an inexpensive and ecofriendly iron-based catalyst and for the insertion of transition metals in a porous architecture, enabling electrochemically driven activation of small molecules

    Properties of q

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    General Relativistic Mean Field Theory for Rotating Nuclei

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    We formulate a general relativistic mean field theory for rotating nuclei starting from the special relativistic σ−ω\sigma - \omega model Lagrangian. The tetrad formalism is adopted to generalize the model to the accelerated frame.Comment: 13 pages, REVTeX, no figures, submitted to Phys. Rev. Lett., the word `curved' is replaced by `non-inertial' or `accelerated' in several places to clarify the physical situation interested, some references are added, more detail discussions are given with omitting some redundant sentence

    Virtual Meson Cloud of the Nucleon and Intrinsic Strangeness and Charm

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    We have applied the Meson Cloud Model (MCM) to calculate the charm and strange antiquark distribution in the nucleon. The resulting distribution, in the case of charm, is very similar to the intrinsic charm momentum distribution in the nucleon. This seems to corroborate the hypothesis that the intrinsic charm is in the cloud and, at the same time, explains why other calculations with the MCM involving strange quark distributions fail in reproducing the low x region data. From the intrinsic strange distribution in the nucleon we have extracted the strangeness radius of the nucleon, which is in agreement with other meson cloud calculations.Comment: 9 pages RevTex, 4 figure
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