4,149 research outputs found

    Cooperative domain type interlayer sp3sp^3-bond formation in graphite

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    Using the classical molecular dynamics and the semiempirical Brenner's potential, we theoretically study the interlayer sigma bond formation, as cooperative and nonlinear phenomena induced by visible light excitations of a graphite crystal. We have found several cases, wherein the excitations of certain lattice sites result in new interlayer bonds even at non-excited sites. We have also found that, a new interlayer bond is easier to be formed around a bond, if it is already existing. As many more sites are going to be excited, the number of interlayer bonds increases nonlinearly with the number of excited sites. This nonlinearity shows 1.7 power of the total number of excited sites, corresponding to about three- or four-photon process.Comment: 7 pages, 8 figure

    Method for detecting coliform organisms

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    A method and apparatus are disclosed for determining the concentration of coliform bacteria in a sample. The sample containing the coliform bacteria is cultured in a liquid growth medium. The cultured bacteria produce hydrogen and the hydrogen is vented to a second cell containing a buffer solution in which the hydrogen dissolves. By measuring the potential change in the buffer solution caused by the hydrogen, as a function of time, the initial concentration of bacteria in the sample is determined. Alternatively, the potential change in the buffer solution can be compared with the potential change in the liquid growth medium to verify that the potential change in the liquid growth medium is produced primarily by the hydrogen gas produced by the coliform bacteria

    Disturbances of both cometary and Earth's magnetospheres excited by single solar flares

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    In the solar wind a comet plays the role of a windvane that moves three-dimensionally in the heliomagnetosphere. Among the solar systems bodies, only comets have a wide range of inclination angles of their orbital planes to the ecliptic plane ranging from 0 to 90 deg. Therefore, observations of cometary plasma tails are useful in probing the heliomagnetospheric conditions in the high heliolatitudinal region. A comet can be compared to a polar-orbiting probe encircling the Sun. We will introduce two rare cases in which the magnetospheres of both the comet and the Earth are disturbed by a single solar flare

    Feasibility of mining lunar resources for earth use: Circa 2000 AD. Volume 1: Summary

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    The feasibility of obtaining lunar minerals for terrestrial uses is examined. Preliminary results gave indications that it will not be economically feasible to mine, refine, and transport lunar materials to Earth for consumption. A broad systems approach was used to analyze the problem. It was determined that even though the procedure was not economically advisable, the concept for the operations is technically sound

    Performance considerations for the astrometric telescope facility on the phase 1 space station

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    The Astrometric Telescope Facility (ATF) is an optical telescope facility of extreme astrometric precision whose principle scientific purpose is the detection and study of planetary systems about nearby stars. With the recent change in the space station program to two phases, the suitability of initial operations from the phase 1 station need to be evaluated. This paper presents the results of such an evaluation for the Astrometric Telescope Facility

    Novel phase transition and the pressure effect in YbFe2Al10-type CeT2Al10 (T=Fe, Ru, Os)

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    We have succeeded in growing single crystals of orthorhombic CeT2Al10 (T=Fe, Ru, Os) by Al self-flux method for the first time, and measured the electrical resistivity at pressures up to 8 GPa, the magnetic susceptibility and specific heat at ambient pressure. These results indicate that CeT2Al10 belongs to the heavy fermion compounds. CeRu2Al10 and CeOs2Al10 show a similar phase transition at T0 = 27.3 and 28.7 K, respectively. The temperature dependences in the ordered phases are well described by the thermally activated form, suggesting that partial gap opens over the Fermi surfaces below T0. When pressure is applied to CeRu2Al10, T0 disappears suddenly between 3 and 4 GPa, and CeRu2Al10 turns into a Kondo insulator, followed by a metal. The similarity of CeT2Al10 under respective pressures suggests a scaling relation by some parameter controlling the unusual physics in these compounds.Comment: 9 pages, 5 figure

    Vibrations and fractional vibrations of rods, plates and Fresnel pseudo-processes

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    Different initial and boundary value problems for the equation of vibrations of rods (also called Fresnel equation) are solved by exploiting the connection with Brownian motion and the heat equation. The analysis of the fractional version (of order ν\nu) of the Fresnel equation is also performed and, in detail, some specific cases, like ν=1/2\nu=1/2, 1/3, 2/3, are analyzed. By means of the fundamental solution of the Fresnel equation, a pseudo-process F(t)F(t), t>0t>0 with real sign-varying density is constructed and some of its properties examined. The equation of vibrations of plates is considered and the case of circular vibrating disks CRC_R is investigated by applying the methods of planar orthogonally reflecting Brownian motion within CRC_R. The composition of F with reflecting Brownian motion BB yields the law of biquadratic heat equation while the composition of FF with the first passage time TtT_t of BB produces a genuine probability law strictly connected with the Cauchy process.Comment: 33 pages,8 figure
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