2,990 research outputs found

    POLICY ISSUES RELATED TO SMALL-SCALE PART-TIME FARMS IN THE NORTHEAST

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    Agricultural and Food Policy,

    Ultraschnelle Relaxation optisch angeregter Elektronen in kleinen Übergangsmetallclustern

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    In the present dissertation the relaxation dynamics of optically excited electrons in free Ni3, Pd3, Pd4, Pd7, and Pt3 has been investigeted. By means of femtosecond pump-probe photoelectron spectroscopy the electronic relaxations in these small transition metal clusters could be observed for the first time in real-time . A quantitative analysis of the data reveals inelastic electron-electron relaxation times in the order of magnitude of 10 to 100 femtoseconds . These unexpected short electronelectron- scattering times are caused by the relatively large density of states in the vicinity of the highest occupied cluster orbital. This large density of states results from the narrow bandwidth of the partially filled d-levels in the transition metal clusters . Other aspects for the enhancement of inelastic electron-electron scattering are the spread of the electronic levels by vibrational broadening and the spill-out of the s/p-electron wave functions intensifying the Coulomb-interaction between the electrons

    Femtosecond x-ray absorption spectroscopy of spin and orbital angular momentum in photoexcited Ni films during ultrafast demagnetization

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    We follow for the first time the evolution of the spin and orbital angular momentum of a thin Ni film during ultrafast demagnetization, by means of x-ray magnetic circular dichroism. Both components decrease with a 130 +/- 40 fs time constant upon excitation with a femtosecond laser pulse. Additional x-ray absorption measurements reveal an increase in the spin-orbit interaction by 6 +/- 2 % during this process. This is the experimental demonstration quantifying the importance of spin-orbit mediated processes during the demagnetization

    Jackknife Estimator of Species Richness with S-PLUS

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    An estimate of the number of species, S , usually called species richness by ecologists, in an area is one of the basic statistics used to ascertain biological diversity. Traditionally ecologists have used the number of species observed in a sample, S_0 , to estimate S , realizing that S_0 is a lower bound for S . One alternative to S_0 is to use a nonparametric procedure such as jackknife resampling. For species richness, a closed form of the jackknife estimator is available. Typically statistical software contains only the traditional iterative form of the jackknife estimator. The purpose of this article is to propose an S-PLUS function for calculating the noniterative first order jackknife estimator of species richness and some associated plots and statistics.

    A monostrain test apparatus

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    Test apparatus is designed for determining tensile strength, modulus of elasticity, elongation, and thermal coefficient of contraction or expansion of uniformly shaped plastics, adhesives, and foam materials over temperature range of 700 to 90 K (800 to -300). Tests may be used in design quality control, and in evaluation of new adhesives and plastic materials

    Cryogenic-Compatible Winchester Connector Mount and Retaining System for Composite Tubes

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    A connector retainer and mounting system has been designed to replace screw-mounting of Winchester connectors. Countersunk screws are normally used to secure connectors to structures, and to keep them from coming apart. These screws are normally put into threaded or through-holes in metallic structures. This unique retainer is designed such that integral posts keep the connector halves retained, and a groove permits a cable tie to be fastened around the retainer and composite tube, thus securing the connector to the structure. The system is compatible for use on cryogenic (and conventional) bonded composite tube assemblies. Screws and tapped/through-holes needed to retain and mount Winchester connectors cannot be used on blind-access composite tubes. This system allows for rapid installation, removal, low-molecular-outgassing materials, and particulate-free installation and removal. Installation and/or changes late in the integration, and test flow with limited access in a cleanroom environment are possible. No sanding or bonding is needed

    Jackknife Estimator of Species Richness with S-PLUS

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    An estimate of the number of species, S , usually called species richness by ecologists, in an area is one of the basic statistics used to ascertain biological diversity. Traditionally ecologists have used the number of species observed in a sample, S0 , to estimate S , realizing that S0 is a lower bound for S . One alternative to S0 is to use a nonparametric procedure such as jackknife resampling. For species richness, a closed form of the jackknife estimator is available. Typically statistical software contains only the traditional iterative form of the jackknife estimator. The purpose of this article is to propose an S-PLUS function for calculating the noniterative first order jackknife estimator of species richness and some associated plots and statistics

    Shape Bonding method

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    The present invention is directed to a method of bonding at least two surfaces together. The methods step of the present invention include applying a strip of adhesive to a first surface along a predefined outer boundary of a bond area and thereby defining a remaining open area there within. A second surface, or gusset plate, is affixed onto the adhesive before the adhesive cures. The strip of adhesive is allowed to cure and then a second amount of adhesive is applied to cover the remaining open area and substantially fill a void between said first and second surfaces about said bond area. A stencil may be used to precisely apply the strip of adhesive. When the strip cures, it acts as a dam to prevent overflow of the subsequent application of adhesive to undesired areas. The method results in a precise bond area free of undesired shapes and of a preferred profile which eliminate the drawbacks of the prior art bonds

    STEM Engagement and Robotics Workshops in the Community

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    It is my objective to inspire and engage students and the public in science, technology, engineering, and math (STEM) through hands on STEM activities during the City of Palmdale's Thursday Nights on the Square (TNOTS) as well as various robotics workshops throughout the AV and the San Bernardino County

    Magnetization of small lead particles

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    The magnetization of an ensemble of isolated lead grains of sizes ranging from below 6 nm to 1000 nm is measured. A sharp disappearance of Meissner effect with lowering of the grain size is observed for the smaller grains. This is a direct observation by magnetization measurement of the occurrence of a critical particle size for superconductivity, which is consistent with Anderson's criterion.Comment: 7 pages, 5 figures, Submitted to PR
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