873 resultados para the non-central chi-square chart


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The effect of scaling (1 μm to 0.09 μm) on the non-quasi-static (NQS) behaviour of the MOSFET has been studied using process and device simulation. It is shown that under fixed gate (Vgs) and drain (Vds) bias voltages, the NQS transition frequency (fNQS) scales as 1/Leff rather than 1/L2eff due to the velocity saturation effect. However, under the practical scaling guidelines, considering the scaling of supply voltage as well, fNQS shows a turn around effect at the sub 100 nm regime. The relation between unity gain frequency (ft) and fNQS is also evaluated and it is shown that ft and fNQS have similar trends with scaling.

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Despite highly conserved core catalytic domains, members of the metallophosphoesterase (MPE) superfamily perform diverse and crucial functions ranging from nucleotide and nucleic acid metabolism to phospholipid hydrolysis. Unique structural elements outside of the catalytic core called ``cap domains'' are thought to provide specialization to these enzymes; however, no directed study has been performed to substantiate this. The cap domain of Rv0805, an MPE from Mycobacterium tuberculosis, is located C-terminal to its catalytic domain and is dispensable for the catalytic activity of this enzyme in vitro. We show here that this C-terminal extension (CTE) mediates in vivo localization of the protein to the cell membrane and cell wall as well as modulates expression levels of Rv0805 in mycobacteria. We also demonstrate that Rv0805 interacts with the cell wall of mycobacteria, possibly with the mycolyl-arabinogalactan-peptidoglycan complex, by virtue of its C terminus, a hitherto unknown property of this MPE. Using a panel of mutant proteins, we identify interactions between active site residues of Rv0805 and the CTE that determine its association with the cell wall. Finally, we show that Rv0805 and a truncated mutant devoid of the CTE produce different phenotypic effects when expressed in mycobacteria. Our study thus provides a detailed dissection of the functions of the cap domain of an MPE and suggests that the repertoire of cellular functions of MPEs cannot be understood without exploring the modulatory effects of these subdomains.

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The heat transfer from a solid phase to an impinging non-isothermal liquid droplet is studied numerically. A new approach based on an arbitrary Lagrangian-Eulerian (ALE) finite element method for solving the incompressible Navier Stokes equations in the liquid and the energy equation within the solid and the liquid is presented. The novelty of the method consists in using the ALE-formulation also in the solid phase to guarantee matching grids along the liquid solid interface. Moreover, a new technique is developed to compute the heat flux without differentiating the numerical solution. The free surface and the liquid solid interface of the droplet are represented by a moving mesh which can handle jumps in the material parameter and a temperature dependent surface tension. Further, the application of the Laplace-Beltrami operator technique for the curvature approximation allows a natural inclusion of the contact angle. Numerical simulation for varying Reynold, Weber, Peclet and Biot numbers are performed to demonstrate the capabilities of the new approach. (C) 2014 Elsevier Ltd. All rights reserved.

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A comprehensive numerical investigation on the impingement and spreading of a non-isothermal liquid droplet on a solid substrate with heterogeneous wettability is presented in this work. The time-dependent incompressible Navier-Stokes equations are used to describe the fluid flow in the liquid droplet, whereas the heat transfer in the moving droplet and in the solid substrate is described by the energy equation. The arbitrary Lagrangian-Eulerian (ALE) formulation with finite elements is used to solve the time-dependent incompressible Navier-Stokes equation and the energy equation in the time-dependent moving domain. Moreover, the Marangoni convection is included in the variational form of the Navier-Stokes equations without calculating the partial derivatives of the temperature on the free surface. The heterogeneous wettability is incorporated into the numerical model by defining a space-dependent contact angle. An array of simulations for droplet impingement on a heated solid substrate with circular patterned heterogeneous wettability are presented. The numerical study includes the influence of wettability contrast, pattern diameter, Reynolds number and Weber number on the confinement of the spreading droplet within the inner region, which is more wettable than the outer region. Also, the influence of these parameters on the total heat transfer from the solid substrate to the liquid droplet is examined. We observe that the equilibrium position depends on the wettability contrast and the diameter of the inner surface. Consequently. the heat transfer is more when the wettability contrast is small and/or the diameter of inner region is large. The influence of the Weber number on the total heat transfer is more compared to the Reynolds number, and the total heat transfer increases when the Weber number increases. (C) 2015 Elsevier Ltd. All rights reserved.

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We report first experimental demonstration on the non-transparent characteristic of FWM using NRZ-DPSK, RZ-DPSK, CSRZ-DPSK, and CSRZ signals. One potential non-transparency application of 40Gbit/s CSRZ-to-RZ format conversion is experimentally demonstrated. © 2008 IEEE.

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in the corona, consisting of an eruptive prominence and/or a magnetic flux region (loop or arcade, or blob) in front of the prominence. Ahead of the piston, there is a compressed flow, which produces a shock front. This high-density region corresponds to the bright feature of the transient. Behind the piston, there is a rarefaction region, which corresponds to the dark feature of the transient. Therefore, both the bright and dark features of the transient may be explained at the same time by the dynamical process of the moving piston.

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In this paper, we first present a system of differential-integral equations for the largedisturbance to the general case that any arbitrarily shaped solid body with a cavity contain-ing viscous liquid rotates uniformly around the principal axis of inertia, and then develop aweakly non-linear stability theory by the Lyapunov direct approach. Applying this theoryto the Columbus problem, we have proved the consistency between the theory and Kelvin'sexperiments.

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The rapidly expanding population and economic growth in the seven counties of the East Central Florida Regional Planning Council as shown in Figure 1, herein called the East Central Florida Region or the Region, has resulted in increasing demands on its water resources. Although there is abundant water in the Region as a whole, the water in some areas of the Region is of unacceptable quality for most uses. As the population increases the demand for water will become much greater and the available supply may be reduced by pollution and increased drainage necessitated by urbanization and other land development- Ground-water supplies can be increased by capturing and storing water underground that now drains to the sea or evaporates from swamp areas. Research is needed, however, to develop artificial-recharge methods that are feasible and which will preserve or improve the quality of water in the aquifer. (PDF contains 57 pages)

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The family Priacanthidae contains four genera and four species that occur in the western central North Atlantic (Starnes, 1988). Pristigenys alta is distributed in the Caribbean, Gulf of Mexico and along the east coast of North America. Although juveniles have been reported from as far north as southern New England waters, adults are not reported north of Cape Hatteras, NC. Priacanthus arenatus is distributed in tropical and tropically influenced areas of the western central North Atlantic in insular and continental shelf waters. Adult P. arenatus are distributed north to North Carolina and Bermuda, juveniles have been collected as far north as Nova Scotia. Cookeolus japonicus and Heteropriacanthus cruentatus are circumglobally distributed species and are both common in insular habitats. In the western central North Atlantic, C. japonicus ranges from New Jersey to Argentina; H. cruentatus from New Jersey and northern Gulf of Mexico to southern Brazil (Starnes, 1988). (PDF contains 6 pages)

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The family Gerreidae contains four genera and 13 species that occur in the western central North Atlantic. Adult gerreids are small to medium size fishes that are abundant in coastal waters, bays, and estuaries in tropical and warm temperate regions and sometimes occur in freshwaters. They are generally associate~ with grassy or open bottoms, but not with reefs. Gerreids are silvery fishes, with deeply forked tails, and extremely protrusible mouth that points downward when protracted. They apparently feed on bottom-dwelling organisms and at least one species (Eucinostomus gula) shows a distinct transition, during the juvenile period, from a planktivore (exclusively copepods) to a carnivore that includes a diet of almost solely polychaetes (Carr & Adams, 1973; Robins and Ray, 1987; Murdy et al., 1997). (PDF contains 10 pages)

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Callionymidae, along with the Draconettidae and Gobiesocidae, previously were placed in the order Gobiesociformes (Allen, 1984). Recently, Nelson (1994) placed the Callionymidae and Draconettidae in the percifonn suborder Callionymoidei. The family is represented by three species in the western central North Atlantic Ocean, Diplogrammus pauciradiatus, Paradiplogrammus bairdi and Foetorepus agassizi (Davis, 1966; Robins and Ray, 1986). A detailed review ofthe family including early life history infonnation is given by Houde (1984) and Watson (1996). (PDF contains 11 pages)

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The formation of the non-uniformity of the non-volatile volume grating in doubly doped LiNbO3 crystals is studied in detail. We find that the non-uniformity of the grating is mainly caused by strong ultraviolet light absorption, and the average saturation space-charge field is small and the diffraction efficiency is low as a result of the non-uniformity of the grating. In order to optimize the uniformity of the grating, we propose the recording scheme by using two sensitizing beams simultaneously from the two opposite sides of the crystals. Theoretical simulations and experimental verifications are performed. Results show that the well uniformed grating with high diffraction efficiency can be obtained by using this optimization scheme. (c) 2004 Elsevier B.V. All rights reserved.

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We examined the effect of habitat and shrimp trawl bycatch on the density, size, growth, and mortality of inshore lizardfish (Synodus foetens), a nonexploited species that is among the most widespread and abundant benthic fishes in the north central Gulf of Mexico. Results of quarterly trawl sampling conducted from spring 2004 through spring 2005 revealed that inshore lizardfish are most abundant on sand habitat, but larger fish are more common on shell rubble habitat. There was no significant difference in fish density between habitats exposed to shrimp trawling on the open shelf versus those habitats within a permitted artificial reef zone that served as a de facto no-trawl area; this finding indicates that either inshore lizardfish experienced minimal effects from trawling or, more likely, that fish moved between trawled and nontrawled habitats. Exploitation ratio (bycatch mortality/total morality) estimates derived from catch curve analysis ranged from 0.43 inside the artificial reef zone to 0.55 outside the reef zone, thus indicating that inshore lizardfish are subject to significant fishing mortality in the north central Gulf of Mexico despite the lack of a directed fishery for the species. We infer from this result that effects of shrimp trawl bycatch may be significant at the population level for nonexploited species and that a broader ecosystem-scale examination of bycatch effects is warranted.