Miracle-dz/UniFAR-FTUs huggingface dataset:
Conductance and giant magnetoconductance of Co{vert_bar}Cu{vert_bar}Co spin valves: Experiment and theory

We present measurements of the conductance and magnetoconductance as a function of cobalt layer thickness for cobalt-copper-cobalt spin valves deposited by magnetron sputtering. We compare these measurements to calculations of the conductance and magnetoconductance, which are based on first-principles calculations of the self-consistent electronic structure of the cobalt-copper-cobalt system. The calculations are performed using a generalized Kubo formula for the nonlocal layer dependent conductivity, which is implemented within the layer Korringa-Kohn-Rostoker method for electronic-structure calculations. The scattering rates within each layer are adjusted phenomenologically to be consistent with the experimentally observed resistivity of thick films of cobalt and copper. The magnetoconductance and its dependence on the thickness of the cobalt layer are consistent with calculations that include strong bulk spin-dependent scattering within the cobalt layers and possibly some channeling of electrons in the copper layer. We find that the transmission and reflection of electrons at the interfaces are strongly spin dependent and that it is not necessary to invoke additional diffuse spin-dependent scattering at the interfaces to explain the conductance and magnetoconductance of these samples. {copyright} {ital 1997} {ital The American Physical Society}
Recursive attitude determination from vector observations Euler angle estimation

This work presents an algorithm that processes a sequence of pairs of measured vectors to obtain a minimum variance estimate of the Euler angles which describe the attitude between two coordinate systems. The measurement equation is nonlinear and, unlike the direction cosine matrix and the quaternion estimation problems, the dynamics of the estimated angles are nonlinear as well. The algorithm can also handle singular cases, thus extending the use of Euler angles to all-attitude vehicles. Results of Monte-Carlo simulations are presented that demonstrate the efficiency of the algorithm. This work is a natural extension of the algorithms that were recently developed for estimating the direction cosine matrix and the quaternion, therefore it completes the set of recursive minimum variance algorithms for estimating the three common forms of expressing attitude.
Near-Surface Intensification of Tornado Vortices

Abstract An idealized analytical model and numerical large-eddy simulations are used to explore fluid-dynamic mechanisms by which tornadoes may be intensified near the surface relative to conditions aloft. The analytical model generalizes a simple model of Barcilon and Fiedler and Rotunno for a steady supercritical end-wall vortex to more general vortex corner flows, angular momentum distributions, and time dependence. The model illustrates the role played by the corner flow swirl ratio in determining corner flow structure and intensification; predicts an intensification of near-surface swirl velocities relative to conditions aloft of Iυ ∼ 2 for supercritical end-wall vortices in agreement with earlier analytical, numerical, and laboratory results; and suggests how larger intensification factors might be achieved in some more general corner flows. Examples of the latter are presented using large-eddy simulations. By tuning the lateral inflow boundary conditions near the surface, quasi-steady vortices exhi.
A covering condition for prime ideals

Commutative rings are studied which have the property that every ideal contained in the union of a collection of prime ideals is contained in one of the prime ideals of the collection. This property is shown to be equivalent to the condition that every prime ideal is the radical of a principal ideal. All rings considered in this note will be commutative. Reis and Viswanathan [1] considered the following property: (*) if an ideal ICUaes Pa where the Pa (aeS) are prime ideals of R then ICPa for some aCS. The principal result of [1] is that a Noetherian ring satisfies (*) if and only if every prime ideal is the radical of a principal ideal. The theorem below shows the hypothesis that the ring be Noetherian is not needed. Also in [1] the authors consider the "apparently weaker" condition: (**) if a prime ideal PCUaEs Pa when the Pa (aC Secondary 13E05, 13F10, 13A10.
Super‐Clausius–Clapeyron scaling of rainfall in a model squall line

The sensitivity of squall rainfall to changes in atmospheric temperature is investigated. For instantaneous rainrates and accumulations up to one hour, extreme rainfall scales with Clausius‐Clapeyron (CC) for temperatures below 24°C and at up to twice CC above 24°C. For longer accumulation periods and higher temperatures the scaling breaks down due to increased propagation of the squall line. For all periods, the storm average rainfall is found to scale at approximately 1.5 times CC over the entire range of temperatures. These results have implications for design parameters for infrastructure that is vulnerable to flooding and for climate change projections. Copyright © 2012 Royal Meteorological Society
Graphical representation of canonical proof: two case studies

An interesting problem in proof theory is to find representations of proof that do not distinguish between proofs that are ‘morally’ the same. For many logics, the presentation of proofs in a traditional formalism, such as Gentzen’s sequent calculus, introduces artificial syntactic structure called ‘bureaucracy’; e.g., an arbitrary ordering of freely permutable inferences. A proof system that is free of bureaucracy is called canonical for a logic. In this dissertation two canonical proof systems are presented, for two logics: a notion of proof nets for additive linear logic with units, and ‘classical proof forests’, a graphical formalism for first-order classical logic. Additive linear logic (or sum–product logic) is the fragment of linear logic consisting of linear implication between formulae constructed only from atomic formulae and the additive connectives and units. Up to an equational theory over proofs, the logic describes categories in which finite products and coproducts occur freely. A notion of proof nets for additive linear logic is presented, providing canonical graphical representations of the categorical morphisms and constituting a tractable decision procedure for this equational theory. From existing proof nets for additive linear logic without units by Hughes and Van Glabbeek (modified to include the units naively), canonical proof nets are obtained by a simple graph rewriting algorithm called saturation. Main technical contributions are the substantial correctness proof of the saturation algorithm, and a correctness criterion for saturated nets. Classical proof forests are a canonical, graphical proof formalism for first-order classical logic. Related to Herbrand’s Theorem and backtracking games in the style of Coquand, the forests assign witnessing information to quantifiers in a structurally minimal way, reducing a first-order sentence to a decidable propositional one. A similar formalism ‘expansion tree proofs’ was presented by Miller, but not given a method of composition. The present treatment adds a notion of cut, and investigates the possibility of composing forests via cut-elimination. Cut-reduction steps take the form of a rewrite relation that arises from the structure of the forests in a natural way. Yet reductions are intricate, and initially not well-behaved: from perfectly ordinary cuts, reduction may reach unnaturally configured cuts that may not be reduced. Cutelimination is shown using a modified version of the rewrite relation, inspired by the game-theoretic interpretation of the forests, for which weak normalisation is shown, and strong normalisation is conjectured. In addition, by a more intricate argument, weak normalisation is also shown for the original reduction relation.
Quantitative investigation of alveolar structures with OCT using total liquid ventilation during mechanical ventilation

To develop new treatment possibilities for patients with severe lung diseases it is crucial to understand the lung function on an alveolar level. Optical coherence tomography (OCT) in combination with intravital microscopy (IVM) are used for imaging subpleural alveoli in animal models to gain information about dynamic and morphological changes of lung tissue during mechanical ventilation. The image content suitable for further analysis is influenced by image artifacts caused by scattering, refraction, reflection, and absorbance. Because the refractive index varies with each air-tissue interface in lung tissue, these effects decrease OCT image quality exceedingly. The quality of OCT images can be increased when the refractive index inside the alveoli is matched to the one of tissue via liquid-filling. Thereby, scattering loss can be decreased and higher penetration depth and tissue contrast can be achieved. To use the advantages of liquid-filling for in vivo imaging of small rodent lungs, a suitable breathing fluid (perfluorodecalin) and a special liquid respirator are necessary. Here we show the effect of liquid-filling on OCT and IVM image quality of subpleural alveoli in a mouse model.
Size and Power of the Error Correction Model Cointegration Test. A Bootstrap Approach

The size and power of the ECM cointegration test are investigated by using the 'bootstrap critical values. ' The purpose of this paper is to show the ability of the bootstrap technique to produce critical values which are much more accurate than the asymptotic ones. The properties of the test have been studied, using Monte Carlo methods, for three different data generating processes. As regards the size of the tests, the authors find that the ECM cointegration test together with the bootstrap critical values perform better than the ECM cointegration test based on the asymptotic critical values. While as regards the power of the tests, the results prove to be similar for the different versions. Copyright 1998 by Blackwell Publishing Ltd
The analytical solution of the Riemann problem in relativistic hydrodynamics

We consider the decay of an initial discontinuity in a polytropic gas in a Minkowski space–time (the special relativistic Riemann problem). In order to get a general analytical solution for this problem, we analyse the properties of the relativistic flow across shock waves and rarefactions. As in classical hydrodynamics, the solution of the Riemann problem is found by solving an implicit algebraic equation which gives the pressure in the intermediate states. The solution presented here contains as a particular case the special relativistic shock-tube problem in which the gas is initially at rest. Finally, we discuss the impact of this result on the development of high-resolution shock-capturing numerical codes to solve the equations of relativistic hydrodynamics.
Effect of ion temperature on arbitrary amplitude ion acoustic solitary waves in quantum electron-ion plasmas

Using Sagdeev’s pseudopotential technique, the effect of ion temperature on the arbitrary amplitude ion acoustic solitary waves in quantum electron-ion plasma is studied. In addition, the effect of ion temperature on the region of existence, as well as on the shape of the solitary waves, is also investigated extensively. It is shown that for large amplitude solitary wave, quantum parameter H does not play any role in determining the region of existence and on the amplitude of the solitary waves. However, H has a significant effect on the width of the solitary wave. It is worth noting that our results are in agreement with previous investigations when the effect of ion temperature is neglected.
Transformation of Datasets in a Linear-based Map Conflation Framework

Overlapping datasets originating from different sources tend to have positional discrepancies between similar objects. The underlying process that generates these discrepancies is usually unknown and is non-homogenous in nature. The non-homogeneity suggests that registration of the datasets should be performed using local transformations; the type of local transformations is, however, an open question. Usually, a local rubber-sheeting transformation that utilizes nodes as counterpart features is applied to solve these discrepancies. However, point-based transformation is adequate only for simple cases. This paper presents a local transformation algorithm based on counterpart linear features. The transformation is more general in essence and suitable to a wide range of cases, especially for transformation of spatial geographic data. The line-based transformation is presented here as part of a linear-based map conflation algorithm, a framework under which this transformation is most likely to be encountered in geographic information systems (GIS). Nevertheless it can also be applied separately as part of different applications.
Numerical Calculation of Three-Dimensional Turbulent Natural Convection in a Cubical Enclosure Using a Two-Equation Model for Turbulence

Etude d'une cavite chauffee par le bas et refroidie sur une portion d'une paroi verticale, les autres parois etant isolees. Calcul des bilans tridimensionnels pour la matiere, l'energie et les composantes de la quantite de mouvement ainsi que pour l'energie cinetique turbulente et la vitesse de dissipation de l'energie cinetique turbulente
Measurement of the hydrodynamic surface roughness of noncolloidal spheres

A new technique for measuring the surface roughness of noncolloidal spheres is presented. The time for a sphere initially in contact with a smooth surface to fall away under the influence of gravity through a viscous fluid is shown to be related to the largest scale of surface roughness of sufficient surface coverage to support the particle. The ratio of the time taken for a sphere to fall one particle diameter from a smooth mica plane to that for the sphere to fall between one radius and one diameter from the plane thus provides a means of measuring the effective hydrodynamic surface roughness of spheres. This technique was employed to measure the roughness of eight types of particles ranging from 43–6350 μm in diameter. The roughnesses were found to be on the order of 10−2 to 10−3 particle radii, and were in agreement with independent observations using a scanning electron microscope and an optical profilometer.
Total size estimation and identification of multiple anomalies in the inverse conductivity problem

We consider the inverse problem of determining multiple anomalies within a homogeneous medium occupied in a region Ω⊂n, n = 2 or 3 from the measurement of voltage response to an injected current on the boundary ∂Ω. We propose a new method of finding the total size of multiple anomalies from the boundary measurement. This algorithm works within a real time and gives a quite precise total size of the anomalies. Next, we present asymptotic formulae which are useful to develop a reconstruction algorithm. Numerical experiments based on the size estimation and asymptotic formulae indicate its efficiency.
(Ga, In)(N, As)-fine structure of the band gap due to nearest-neighbor configurations of the isovalent nitrogen

An intrinsic property of quaternary alloys ${A}_{1\ensuremath{-}y}{B}_{y}{C}_{1\ensuremath{-}x}{D}_{x} (x\ensuremath{\approx}1\char21{}3%)$ with D being an isovalent trap is reported: a set of discrete band gaps occurs due to substitution of the isovalent trap D on sites with different nearest-neighbor environments. Exemplary, this phenomenon is demonstrated for (Ga,In)(N,As) by experiment and explained by tight-binding supercell calculations. The band gap of this nitrogen-poor alloy is blueshifted by simply moving the nitrogen isovalent traps from Ga-ligand rich sites to In-ligand rich sites, without changing the alloy composition.
Electromechanical response of 1-3 piezoelectric composites: Effect of poling characteristics

The present study characterizes the effects of variations in the poling characteristics of the matrix and the fiber phase on the overall electromechanical behavior of a 1-3 piezocomposite. Upon identifying 15 types of 1-3 piezocomposites based on two factors: the spatial arrangement of the fibers and the relative orientation of the poling direction of one phase with respect to the second phase, a comprehensive finite-element-based numerical model that can fully capture the electromechanical response of all the 15 types of 1-3 piezocomposites is developed and the following principal results are obtained: (i) a judicious selection of the combination of poling characteristics of the individual constituents, that each exhibit unidirectional sensitivity, could lead to the development of a piezocomposite with significant bidirectional sensitivity; (ii) variations in the elastic, piezoelectric, and dielectric material constants with fiber volume fraction are in general nonlinear, while converging to the expected.
The Rayleigh—Taylor problem with a vertical magnetic field, including the effects of Hall current and resistivity

The influence of resistivity and Hall current on the Rayleigh-Taylor problem involving two superposed fluids of finite density in the presence of gravitational and magnetic fields normal to the fluid interface is examined. Unlike the related problem in which the magnetic field is parallel to the interface, it appears that the dispersion relation does not exhibit singular behaviour in the zero resistivity limit. The ‘potentially stable’ situation is considered throughout. The results are compared with earlier ideal and resistive theories, and an apparent anomaly regarding the existence of normal modes in such systems is resolved.
Chaotic simulated annealing in multilayer feedforward networks

This paper presents a method of chaotic simulated annealing for avoiding and subsequently escaping from local minima in the training of multilayer feedforward neural networks. A modified form of the standard simulated annealing algorithm is implemented using both Gaussian random numbers and various types of strange chaotic attractors for perturbation of network weight parameters. Specifically, the attractor generated by the logistic equation, Henon's (1976) attractor Rossler's attractor, and the Lorenz attractor are used at different initial conditions and parametric variations for chaotic perturbations. The variance fractal dimension is used as a quantitative measure of the geometric properties of the strange chaotic attractors. It is shown that, for this application, chaotic simulated annealing using the logistic equation is up to 600 percent faster than conventional simulated annealing with Gaussian random numbers.
Stability analysis for a class of switched linear systems

This paper investigates the stability of a class of switched linear systems, and proposes a number of new results on the stability analysis. A novel analysis method is developed by using the 2‐norm technique, and then several stability results are obtained based on the new analysis method. It is shown that the main results obtained in this paper not only guarantee the stability of the systems under arbitrary switching, but also provide an algorithm to find the minimum dwell time (MDT) with which switches make the switched systems stable. Finally, several illustrative examples with numerical simulations are studied by using the results obtained in this paper. The study of examples shows that our analysis method works very well in analyzing the stability of some classes of switched linear systems and, moreover, it has some advantages over the common quadratic Lyapunov function method in some cases.
Comparison of conditional sampling and averaging techniques in a turbulent boundary layer

Visual examination of simultaneous temperature traces from a rake of cold wires placed across a turbulent boundary layer had enabled the identification of coherent temperature fronts. An X-wirelcold-wire arrangement was used simultaneously with the rake to provide measurements of the velocity fluctuations u (longitudinal) and v (normal) and the temperature fluctuation θ. Conditional averages of u, v, θ and products uv, uθ, vθ were obtained by application of conditional techniques based on the detection of the temperature fronts using information obtained at only one point in space. These averages, obtained at various positions across the layer, have been compared with those obtained when the rake was used to detect the fronts. The comparison has indicated that none of the one-point detection techniques is in good quantitative agreement with the rake detection technique, the largest correspondence between the rake technique and any ofthe other one-point techniques being only 51 yo. With the exception of the hole technique used in conjunction with the quadrant decomposition analysis, conditional averages obtained from one-point techniques are in reasonable qualitative agreement with those deduced using the rake.
Fully Nonlinear Boussinesq-Type Equations for Waves and Currents over Porous Beds

The paper introduces a complete set of Boussinesq-type equations suitable for water waves and wave-induced nearshore circulation over an inhomogeneous, permeable bottom. The derivation starts with the conventional expansion of the fluid particle velocity as a polynomial of the vertical coordinate z followed by the depth integration of the vertical components of the Euler equations for the fluid layer and the volume-averaged equations for the porous layer to obtain the pressure field. Inserting the kinematics and pressure field into the Euler and volume-averaged equations on the horizontal plane results in a set of Boussinesq-type momentum equations with vertical vorticity and z -dependent terms. A new approach to eliminating the z dependency in the Boussinesq-type equations is introduced. It allows for the existence and advection of the vertical vorticity in the flow field with the accuracy consistent with the level of approximation in the Boussinesq-type equations for the pure wave motion. Examination of.
Global Positioning System Total Electron Content Variation over King Sejong Station in Antarctic under the Solar Minimum Condition Between 2005 and 2009

The total electron content (TEC) using global positioning system (GPS) is analyzed to see the characteristics of ionosphere over King Sejong station (KSJ, geographic latitude , longitude , corrected geomagnetic latitude ) in Antarctic. The GPS operational ratio during the observational period between 2005 and 2009 is 90.1%. The annual variation of the daily mean TEC decreases from January 2005 to February 2009, but increase from the June 2009. In summer (December-February), the seasonal mean TEC values have the maximum of 26.2 2.4 TEC unit (TECU) in 2005 and the minimum of 16.5 2.8 TECU in 2009, and the annual differences decrease from 3.0 TECU (2005-2006) to 1.4 TECU (2008-2009). However, on November 2010, it significantly increases to 22.3 2.8 TECU which is up to 5.8 TECU compared with 2009 in summer. In winter (June-August), the seasonal mean TEC slightly decreases from 13.7 4.5 TECU in 2005 to 8.9 0.6 TECU in 2008, and the annual difference is constantly about 1.6 TECU, and increases to 10.3 1.8 TECU in 2009. The annual variations of diurnal amplitude show the seasonal features that are scattered in summer and the enhancements near equinoxes are apparent in the whole years. In contrast, the semidiurnal amplitudes show the disturbed annual peaks in winter and its enhancements near equinoxes are unapparent. The diurnal phases are not constant in winter and show near 12 local time (LT). The semidiurnal phases have a seasonal pattern between 00 LT and 06 LT. Consequently, the KSJ GPS TEC variations show the significant semidiurnal variation in summer from December to February under the solar minimum between 2005 and 2009. The feature is considered as the Weddell Sea anomaly of larger nighttime electron density than a daytime electron density that has been observed around the Antarctica peninsula.