3,293 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

    Our Rapid Advances Have Prepared Us for the Demands of the Future

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    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

    Raised polyamines in erythrocytes from melanoma-bearing mice and patients with solid tumours

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    The levels of polyamines (putrescine, spermidine and spermine) in erythrocytes and plasma were studied using Cloudman S-91 melanoma grown in the lungs of DBA/2 mice. Polyamine levels and the numbers of tumour-cell colonies in the lungs were determined at weekly intervals. Putrescine levels in both erythrocytes and plasma significantly increased 1 week after tumour inoculation. Three weeks after inoculation, however, putrescine levels in the erythrocytes showed a greater increase than those in plasma. Spermidine and spermine levels were initially high at 2 weeks in plasma and at 4 weeks in erythrocytes. However, by 6 weeks the spermidine levels showed a greater increase in erythrocytes than in plasma. These data suggest that erythrocytes may absorb and store polyamines released into the circulation

    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

    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
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