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71.
72.
Cristian Ravariu 《Simulation Modelling Practice and Theory》2010,18(9):1274-1285
The SOI transistors permanently offer new candidates as nanodevices. The nothing on insulator NOI transistor was recently derived from the nano SOI–MOSFET family. Their output characteristics were theoretical modelled with an exponential law, validated by simulations. The transfer characteristics presented sometimes increasing and others times decreasing monotony. This phenomenon was put directly into a relationship with the gate tunnelling breakdown. This paper has three final targets: the breakdown limitation through the back-gate terminal, the real effects including in the NOI transistor architecture – like interface charges or metal-semiconductor work function and quantum effects corrections in simulations, in order to produce a better correlation between simulations and a real behaviour. These simulations represent a milestone in the NOI nanotransistor manufacturing, establishing some parameters that link the device to the real work regime. 相似文献
73.
Rogério Cezar de Cerqueira Leite Manoel Regis Lima Verde Leal Luís Augusto Barbosa Cortez W. Michael Griffin Mirna Ivonne Gaya Scandiffio 《Energy》2009
Increasing use of petroleum, coupled with concern for global warming, demands the development and institution of CO2 reducing, non-fossil fuel-based alternative energy-generating strategies. Ethanol is a potential alternative, particularly when produced in a sustainable way as is envisioned for sugarcane in Brazil. We consider the expansion of sugarcane-derived ethanol to displace 5% of projected gasoline use worldwide in 2025. With existing technology, 21 million hectares of land will be required to produce the necessary ethanol. This is less than 7% of current Brazilian agricultural land and equivalent to current soybean land use. New production lands come from pasture made available through improving pasture management in the cattle industry. With the continued introduction of new cane varieties (annual yield increases of about 1.6%) and new ethanol production technologies, namely the hydrolysis of bagasse to sugars for ethanol production and sugarcane trash collection providing renewable process energy production, this could reduce these modest land requirements by 29–38%. 相似文献
74.
A method to determine the refractive index and thickness of silver halide emulsions used in holography is presented. The emulsions are in the form of a layer of film deposited on a thick glass plate. The experimental reflectances of p-polarized light are measured as a function of the incident angles, and the values of refractive index, thickness, and extinction coefficient of the emulsion are obtained by using the theoretical equation for reflectance. As examples, five commercial holographic silver halide emulsions are analyzed. The procedure to obtain the measurements and the numerical analysis of the experimental data are simple, and agreement of the calculated reflectances, by use of the thickness and refractive index obtained, with the measured reflectances is satisfactory. 相似文献
75.
Paulo Cortez Manuel Portelinha Sandra Rodrigues Vasco Cadavez Alfredo Teixeira 《Neural Processing Letters》2006,24(1):41-51
The correct assessment of meat quality (i.e., to fulfill the consumer’s needs) is crucial element within the meat industry. Although there are several factors that affect the perception of taste, tenderness is considered the most important characteristic. In this paper, a Feature Selection procedure, based on a Sensitivity Analysis, is combined with a Support Vector Machine, in order to predict lamb meat tenderness. This real-world problem is defined in terms of two difficult regression tasks, by modeling objective (e.g. Warner–Bratzler Shear force) and subjective (e.g. human taste panel) measurements. In both cases, the proposed solution is competitive when compared with other neural (e.g. Multilayer Perceptron) and Multiple Regression approaches. 相似文献
76.
77.
In this paper it is shown that some of the useful network transformations, such as low pass (LP) to band pass (BP), LP to high pass (HP) and HP to BP can be obtained by means of the complementary transformation (CT). Furthermore, because the CT is a topological one (i.e. the component values remain unchanged, but their position within the circuit changes), it is suitable to realize reconfigurable analogue filter arrays. As an example, a full list of the obtainable GIC‐based filters, along with their design equations, is also presented. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
78.
BACKGROUND:. Modern biological research is highly dependent upon recombinant DNA technology. Conventional cloning methods are time-consuming and lack uniformity. Thus, biological research is in great need of new techniques to rapidly, systematically and uniformly manipulate the large sets of genes currently available from genome projects. RESULTS:. We describe a series of new cloning methods that facilitate the rapid and systematic construction of recombinant DNA molecules. The central cloning method is named the univector plasmid-fusion system (UPS). The UPS uses Cre-lox site-specific recombination to catalyze plasmid fusion between the univector - a plasmid containing the gene of interest - and host vectors containing regulatory information. Fusion events are genetically selected and place the gene under the control of new regulatory elements. A second UPS-related method allows for the precise transfer of coding sequences only from the univector into a host vector. The UPS eliminates the need for restriction enzymes, DNA ligases and many in vitro manipulations required for subcloning, and allows for the rapid construction of multiple constructs for expression in multiple organisms. We demonstrate that UPS can also be used to transfer whole libraries into new vectors. Additional adaptations are described, including directional PCR cloning and the generation of 3' end gene fusions using homologous recombination in Escherichia coli. CONCLUSIONS:. Together, these recombination-based cloning methods constitute a new comprehensive approach for the rapid and efficient generation of recombinant DNA that can be used for parallel processing of large gene sets, a feature that will facilitate future genomic analysis. 相似文献
79.
Cristian Bucilă Johannes Gehrke Daniel Kifer Walker White 《Data mining and knowledge discovery》2003,7(3):241-272
Recently, constraint-based mining of itemsets for questions like find all frequent itemsets whose total price is at least $50 has attracted much attention. Two classes of constraints, monotone and antimonotone, have been very useful in this area. There exist algorithms that efficiently take advantage of either one of these two classes, but no previous algorithms can efficiently handle both types of constraints simultaneously. In this paper, we present DualMiner, the first algorithm that efficiently prunes its search space using both monotone and antimonotone constraints. We complement a theoretical analysis and proof of correctness of DualMiner with an experimental study that shows the efficacy of DualMiner compared to previous work. 相似文献
80.
Cristian A. Solari John O. Kessler Raymond E. Goldstein 《Genetic Programming and Evolvable Machines》2007,8(2):115-129
A fundamental issue in evolutionary biology is the transition from unicellular to multicellular organisms, and the cellular
differentiation that accompanies the increase in group size. Here we consider recent results on two types of “multicellular”
systems, one produced by many unicellular organisms acting collectively, and another that is permanently multicellular. The
former system is represented by groups of the bacterium Bacillus subtilis and the latter is represented by members of the colonial volvocalean green algae. In these flagellated organisms, the biology
of chemotaxis, metabolism and cell–cell signaling is intimately connected to the physics of buoyancy, motility, diffusion,
and mixing. Our results include the discovery in bacterial suspensions of intermittent episodes of disorder and collective
coherence characterized by transient, recurring vortex streets and high-speed jets of cooperative swimming. These flow structures
markedly enhance transport of passive tracers, and therefore likely have significant implications for intercellular communication.
Experiments on the Volvocales reveal that the sterile flagellated somatic cells arrayed on the surface of Volvox colonies are not only important for allowing motion toward light (phototaxis), but also play a crucial role in driving fluid
flows that transport dissolved molecular species. These flows, generated by the collective beating of flagella, confer a synergistic
advantage with regard to transport of nutrients and chemical messengers. They allow these species to circumvent a nutrient
acquisition bottleneck which would exist if transport were purely diffusive, and thereby evolve to larger multicellular individuals.
In both cases, a higher level of organization, specialization and complexity counteract the higher costs inherent to larger
groups. 相似文献