5,925 research outputs found

    Expansion of CMOS array design techniques

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    The important features of the multiport (double entry) automatic placement and routing programs for standard cells are described. Measured performance and predicted performance were compared for seven CMOS/SOS array types and hybrids designed with the high speed CMOS/SOS cell family. The CMOS/SOS standard cell data sheets are listed and described

    Diffusion and utilization of scientific and technological knowledge within state and local governments: Executive summary

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    The requirements for technology transfer among the state and local governments are analyzed. Topics discussed include: information systems, federal funding, delivery channels, state executive programs, and state legislature requirements for scientific information

    Subexponential instability implies infinite invariant measure

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    We study subexponential instability to characterize a dynamical instability of weak chaos. We show that a dynamical system with subexponential instability has an infinite invariant measure, and then we present the generalized Lyapunov exponent to characterize subexponential instability.Comment: 7 pages, 5 figure

    CMOS array design automation techniques

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    A low cost, quick turnaround technique for generating custom metal oxide semiconductor arrays using the standard cell approach was developed, implemented, tested and validated. Basic cell design topology and guidelines are defined based on an extensive analysis that includes circuit, layout, process, array topology and required performance considerations particularly high circuit speed

    Chaotic itinerancy and power-law residence time distribution in stochastic dynamical system

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    To study a chaotic itinerant motion among varieties of ordered states, we propose a stochastic model based on the mechanism of chaotic itinerancy. The model consists of a random walk on a half-line, and a Markov chain with a transition probability matrix. To investigate the stability of attractor ruins in the model, we analyze the residence time distribution of orbits at attractor ruins. We show that the residence time distribution averaged by all attractor ruins is given by the superposition of (truncated) power-law distributions, if a basin of attraction for each attractor ruin has zero measure. To make sure of this result, we carry out a computer simulation for models showing chaotic itinerancy. We also discuss the fact that chaotic itinerancy does not occur in coupled Milnor attractor systems if the transition probability among attractor ruins can be represented as a Markov chain.Comment: 6 pages, 10 figure

    Optical Investigation of Transition Metal Implanted Wide Band Gap Semiconductors

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    Thin films of GaN, Al0.1Ga0.9N, and ZnO were implanted with Cr, Mn, and nickel Ni to produce dilute magnetic semiconductors. Optical and magnetic techniques were used to evaluate crystal structure restoration and coercive field strength as a function of implant species and annealing temperature. Maximum crystal restoration was obtained for Al0.1Ga0.9N after annealing at 675 °C; for Cr implanted p-GaN after annealing at 750 °C; for Mn or Ni implanted p-GaN after annealing at 675 °C; for Cr implanted ZnO after annealing at 700 °C; for Mn implanted ZnO after annealing at 675 °C; and for Ni implanted ZnO after annealing at 650 °C. Maximum coercive field strengths were found for Cr implanted Al0.1Ga0.9N after annealing at 750 °C; for Mn implanted Al0.1Ga0.9N after annealing at 675 °C; for Ni implanted Al0.1Ga0.9N after annealing at 700 °C; for Cr or Mn implanted p-GaN after annealing at 725 °C; for Ni implanted p-GaN after annealing at 675 °C; for Cr or Ni implanted ZnO after annealing at 725 °C; and for Mn implanted ZnO after annealing at 725 °C. Optimum annealing conditions for optical and magnetic properties of the implanted wide band gap semiconductors agree with each other very well

    Quiescence: a mechanism for escaping the effects of drug on cell populations

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    We point out that a simple and generic strategy to lower the risk for extinction consists in the developing a dormant stage in which the organism is unable to multiply but may die. The dormant organism is protected against the poisonous environment. The result is to increase the survival probability of the entire population by introducing a type of zero reproductive fitness. This is possible, because the reservoir of dormant individuals act as a buffer that can cushion fatal fluctuations in the number of births and deaths which without the dormant population would have driven the entire population to extinction.Comment: 18 pages and 9 figure

    On classical upper bounds for slice genera

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    We introduce a new link invariant called the algebraic genus, which gives an upper bound for the topological slice genus of links. In fact, the algebraic genus is an upper bound for another version of the slice genus proposed here: the minimal genus of a surface in the four-ball whose complement has infinite cyclic fundamental group. We characterize the algebraic genus in terms of cobordisms in three-space, and explore the connections to other knot invariants related to the Seifert form, the Blanchfield form, knot genera and unknotting. Employing Casson-Gordon invariants, we discuss the algebraic genus as a candidate for the optimal upper bound for the topological slice genus that is determined by the S-equivalence class of Seifert matrices

    Entropy-driven cutoff phenomena

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    In this paper we present, in the context of Diaconis' paradigm, a general method to detect the cutoff phenomenon. We use this method to prove cutoff in a variety of models, some already known and others not yet appeared in literature, including a chain which is non-reversible w.r.t. its stationary measure. All the given examples clearly indicate that a drift towards the opportune quantiles of the stationary measure could be held responsible for this phenomenon. In the case of birth- and-death chains this mechanism is fairly well understood; our work is an effort to generalize this picture to more general systems, such as systems having stationary measure spread over the whole state space or systems in which the study of the cutoff may not be reduced to a one-dimensional problem. In those situations the drift may be looked for by means of a suitable partitioning of the state space into classes; using a statistical mechanics language it is then possible to set up a kind of energy-entropy competition between the weight and the size of the classes. Under the lens of this partitioning one can focus the mentioned drift and prove cutoff with relative ease.Comment: 40 pages, 1 figur

    Noise-enhanced trapping in chaotic scattering

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    We show that noise enhances the trapping of trajectories in scattering systems. In fully chaotic systems, the decay rate can decrease with increasing noise due to a generic mismatch between the noiseless escape rate and the value predicted by the Liouville measure of the exit set. In Hamiltonian systems with mixed phase space we show that noise leads to a slower algebraic decay due to trajectories performing a random walk inside Kolmogorov-Arnold-Moser islands. We argue that these noise-enhanced trapping mechanisms exist in most scattering systems and are likely to be dominant for small noise intensities, which is confirmed through a detailed investigation in the Henon map. Our results can be tested in fluid experiments, affect the fractal Weyl's law of quantum systems, and modify the estimations of chemical reaction rates based on phase-space transition state theory.Comment: 5 pages, 5 figure
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