3,177 research outputs found

    Variable angle photoelectron spectrometer

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    The design, construction, and performance of a spectrometer for measuring the angular and energy distributions of electrons photoejected by rare gas resonance light is described. Results using 584.4‐Å photons from a helium lamp are reported. Flexibility of instrumental design allows for the use of other light sources. A 180° hemispherical electrostatic electron energy analyzer is rotatable about the center of an enclosed sample chamber. The instrument is highly automated, with an on‐line computer used to control the detector angle and the data acquisition and reduction. This automation is required by the long and continuous data acquisition

    Impact of randomly distributed dopants on Ω-gate junctionless silicon nanowire transistors

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    This paper presents experimental and simulation analysis of an Ω-shaped silicon junctionless nanowire field-effect transistor (JL-NWT) with gate lengths of 150 nm and diameter of the Si channel of 8 nm. Our experimental measurements reveal that the ON-currents up to 1.15 mA/Όm for 1.0 V and 2.52 mA/Όm for the 1.8-V gate overdrive with an OFF-current set at 100 nA/Όm. Also, the experiment data reveal more than eight orders of magnitude ON-current to OFF-current ratios and an excellent subthreshold slope of 66 mV/dec recorded at room temperature. The obtained experimental current-voltage characteristics are used as a reference point to calibrate the simulations models used in this paper. Our simulation data show good agreement with the experimental results. All simulations are based on drift-diffusion formalism with activated density gradient quantum corrections. Once the simulations methodology is established, the simulations are calibrated to the experimental data. After this, we have performed statistical numerical experiments of a set of 500 different JL-NWTs. Each device has a unique random distribution of the discrete dopants within the silicon body. From those statistical simulations, we extracted important figures of merit, such as OFF-current and ON-current, subthreshold slope, and voltage threshold. The performed statistical analysis, on samples of those 500 JL-NWTs, shows that the mean ID-VGs characteristic is in excellent agreement with the experimental measurements. Moreover, the mean ID-VGs characteristic reproduces better the subthreshold slope data obtained from the experiment in comparison to the continuous model simulation. Finally, performance predictions for the JL transistor with shorter gate lengths and thinner oxide regions are carried out. Among the simulated JL transistors, the configuration with 25-nm gate length and 2-nm oxide thickness shows the most promising characteristics offering scalable designs

    Normative Influence and Rational Conflict Decisions: Group Norms and Cost-Benefit Analyses for Intergroup Behavior

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    The present paper articulates a model in which ingroup and outgroup norms inform ‘rational’ decision-making (cost-benefit analysis) for conflict behaviors. Norms influence perceptions of the consequences of the behavior, and individuals may thus strategically conform to or violate norms in order to acquire benefits and avoid costs. Two studies demonstrate these processes in the context of conflict in QuĂ©bec. In the first study, Anglophones’ perceptions of Francophone and Anglophone norms for pro-English behaviors predicted evaluations of the benefits and costs of the behaviors, and these cost-benefit evaluations in turn mediated the norm-intention links for both group norms. In the second study, a manipulated focus on supportive versus hostile ingroup and outgroup norms also predicted cost-benefit evaluations, which mediated the norm-intention relationships. The studies support a model of strategic conflict choices in which group norms inform, rather than suppress, rational expectancy-value processes. Implications for theories of decision-making and normative influence are discussed

    The connective Morava K-theory of the second mod p Eilenberg-MacLane space

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    We develop tools for computing the connective n-th Morava K-theory of spaces. Starting with a Universal Coefficient Theorem that computes the cohomology version from the homology version, we show that every step in the process of computing one is mirrored in the other and that this can be used to make computations. As our example, we compute the connective n-th Morava K-theory of the second mod p Eilenberg-MacLane space.Comment: minor change of title and one sentence adde

    Restoration of Aspen-Dominated Ecosystems in the Lake States

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    A reserve tree method (RTM) of harvesting was installed in six 70 to 75 year old aspen dominated stands to determine if retaining 10 to 15 dominant aspen per acre would decrease sucker density to facilitate restoration of a conifer component. A reserve shelterwood cut was applied to three additional stands to evaluate performance of white pine planted under 50% crown cover. After the first full growing season following harvest, 96% of the RTM harvested areas were stocked; sucker density averaged 27000 per acre versus 38.2 k per acre on a clearcut control, 41% greater. Basal diameter of dominant suckers averaged 0.45 inch, 28% greater than the control, and mean height was 60 inches, 33% greater. The control site had 3.1k stems per acre of associated commercial species versus 5.8 k on the RTM sites, an 87% difference. Four of the nine stands have been planted; first-year survival ranged from 75% to near 100%. The RTM shows promise for reducing sucker density, increasing their early growth, maintaining species diversity, and providing abundant regeneration of commercial species on a high proportion of the areas harvested. Early results indicate that both the RTM and shelterwood methods can facilitate restoring a component of native conifer species in these ecosystems

    Wireless Chemical Sensor and Sensing Method for Use Therewith

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    A wireless chemical sensor includes an electrical conductor and a material separated therefrom by an electric insulator. The electrical conductor is an unconnected open-circuit shaped for storage of an electric field and a magnetic field. In the presence of a time-varying magnetic field, the first electrical conductor resonates to generate harmonic electric and magnetic field responses. The material is positioned at a location lying within at least one of the electric and magnetic field responses so-generated. The material changes in electrical conductivity in the presence of a chemical-of-interest

    A normative study of students selected at random on the H.M.H. plus and minus binocular rock test

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    A normative study of students selected at random on the H.M.H. plus and minus binocular rock tes

    Experimental and Simulation Study of a High Current 1D Silicon Nanowire Transistor Using Heavily Doped Channels

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    Silicon nanowires have numerous potential applications, including transistors, memories, photovoltaics, biosensors and qubits [1]. Fabricating a nanowire with the required characteristics for a specific application, however, poses some challenges. For example, a major challenge is that, as the transistors dimensions are reduced, it is difficult to maintain a low off-current (Ioff) whilst simultaneously maintaining a high on-current (Ion). Some sources of this parasitic leakage current include quantum mechanical tunnelling, short channel effects and statistical variability [2, 3]. A variety of new architectures, including ultra-thin silicon-on-insulator (SOI), double gate, FinFETs, tri-gate, junctionless and gate all-around (GAA) nanowire transistors, have therefore been developed to improve the electrostatic control of the conducting channel. This is essential since a low Ioff implies low static power dissipation and it will therefore improve power management in the multi-billion transistors circuits employed globally in microprocessors, sensors and memories

    Cyclosporin A protects hepatocytes subjected to high Ca2+ and oxidative stress

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    AbstractHepatocytes incubated with 0.8 mM t-butylhydroperoxide are protected by cyclosporin A when the medium Ca2+ concentration is 10 mM, but not when it is 2.5 mM. The highest Ca2+ level is associated with an inhibition of t-butylhydroperoxide-dependent malondialdehyde accumulation and with mitochondrial Ca2+ loading within the cells. These findings are new evidence that t-butylhydroperoxide can kill cells by peroxidation-dependent and -independent mechanisms, and suggest that the mitochondrial permeability transition and the resultant de-energization are components of the peroxidation-independent mechanism. Cyclosporin A may have considerable utility for the protection of cells subjected to oxidative stress
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