Miracle-dz/UniFAR-FTUs huggingface dataset:
Multipole analysis of unidirectional light scattering from plasmonic dimers

We analyze unidirectional scattering produced by sub-wavelength plasmonic dimers formed by two silver strips separated by a thin dielectric spacer and embedded in a uniform dielectric medium. Achieving the Kerker condition, which requires matching the strengths of the electric and magnetic-type contributions of the same multipolar order, is possible with such structures for both forward and backward unidirectional scattering by matching the geometric shape-leveraged resonant magnetic dipolar response with the off-resonant electric dipolar contribution. However, unidirectionality is strongly affected by coupling between the two elements in the dimer structure, leading to the manifestation of the electric quadrupole response in the far field. We develop an approach allowing for an easy inverse scattering retrieval of various multipole contributions to the far-field pattern produced by this type of geometry. The retrieval shows unambiguously that the electric quadrupole response contributes up to 30% of the scattered far-field intensity, in addition to strong manifestation of both electric and magnetic dipolar modes. A modified condition for unidirectionality can be developed based on the principle that suppression of radiation in either the forward or backward direction can be achieved whenever the combined strength of multipolar modes of a certain parity, radiating along the propagation direction, matches that of an opposite parity, and noting that parities of electric and magnetic modes interchange with increasing multipole order. With this condition satisfied, unidirectionality of 26 dB/17 dB for forward/backward scattering, respectively, can be achieved with dimer geometries. We also perform a detailed quantitative analysis of scattering cross sections of dimer structures compared to those of Si and gold spheres, accounting for the actual material losses. We show that dimer structures allow for improving backscattering unidirectionality by 10 dB compared to what is achievable with Si spheres, owing to their reliance on off-resonant electric dipolar response; they also allow for a significant (below λ / 10 ? > ) reduction of the size of a unidirectionally scattering nanoelement.
Estimation of parameters of a continuous time Gaussian stationary process with rational spectral density

The estimation of parameters in a continuous time Gaussian stationary process with zero mean and rational spectral density is achieved by an adaptation of the maximum likelihood method. It consists of minimizing something analogous to the sum of the squares of the residuals in the discrete case. The estimate is shown to be asymptotically normal and efficient. A simple computational procedure is also given to construct the estimate.
Statistical spectral analysis : a nonprobabilistic theory

This book presents a general theory and methodology for empirical spectral analysis. The treatment is original because it does not make use of the difficult concept of ergodicity to provide a link between the empirical methods and the abstract probabilistic theory of stochastic processes. Instead, it shows that all the concepts and methods of empirical spectral analysis can be explained in a more straightforward fashion in terms of a deterministic theory: a theory based on time-averages of a single time-series rather than ensemble-averages of hypothetical random samples from an abstract probabilistic model. Specifically, the fundamental concepts and methods of empirical spectral analysis are explained without use of probability calculus. This approach is in keeping with the profound and influential work of Norbert Wiener in his classic paper Generalized Harmonic Analysis published in 1930. Part I of this book is intended to serve as both a graduatelevel textbook and a technical reference. The only prerequisite is an introductory course on Fourier analysis. However, some prior exposure to probability and statistics would be helpful. Part I presents a thorough development of fundamental concepts and results in the theory of statistical spectral analysis of empirical time-series from constant phenomena. The approach given here is one that will be helpful to students, for
Renol~alization-group fixed points of general n-vector models

The coefficient a is temperature dependent and vanishes at Nearly half a century ago, Landau introduced a model for second-order phase transitions. ' It is a mean-field theory, and it yields fairly good predictions for the nature of the symmetry changes between the two phases, but it naturally fails to predict the critical exponents. The renormalization-group method of Wilson and its application to quartic Hamiltonian made in Refs. 3—5 can be used to improve Landau theory, as was suggested in Refs. 6—8. For the last seven years many examples of actual second-order phase transitions have been studied by this method. However, for this type of Hamiltonian, a general study of the existence and stability of the renormalization-group fixed points is lacking. The aim of this paper is to explain what is known on this topic and give new results; e.g., when it exists, the stable fixed point is unique and all other fixed points are (to the lowest order in the e expansion) on the boundary of its attractor basin. In addition, the "intriguing conjecture" on the critical exponents made at the end of the paper' by Brezin, Le Guillou, and Zinn-Justin is proven. We consider a physical system in thermodynamical equilibrium (e.g., a crystal) with its symmetry group I (e.g., one of the 230 three-dimensional crystallographic space groups). At the phase transition the system state is described by a vector P belonging to an n-dimensional real vector space 8'„, which carries an irreducible orthogonal representation of I":
NGC 1058 - Gas motions in an extended, quiescent spiral disk

The motion of gas in the galaxy NGC 1058 is examined, using VLA observations to map emission in the 21-cm line. The hypothesis that the rotation curve drops faster than Keplerian at the outer edge of the disk is confirmed. It is found that the line width decreases with optical surface brightness, but in the extended gas disk beyond the Holmberg radius, the line width is constant. The observations show no correlation between line width and spiral phase of H I surface density in the outer disk. Evidence is found for an intermediate velocity cloud population with a velocity width several times broader than that of the bulk of the H I in the optically bright disk. 29 refs.
The Effect of Variable Sea Surface Temperature on Forecasting Sea Fog and Sea Breezes: A Case Study

AbstractA preliminary study of the effect of sea surface temperature (SST) temporal and spatial variability on regional coastal weather forecasts is described. A high-resolution numerical weather forecast model from the Met Office is run for the U.K. region with hourly updates of SST data obtained from a shelf sea model. When compared with a control run in which SST is maintained with Operational Sea Surface Temperature and Sea Ice Analysis (OSTIA) data, it is found that there are significant differences in the coastal-region forecasts for sea breezes and fog formation. The control run underestimates surface temperature and the strength of the sea breeze when compared with the run with hourly SST updates.
Maximal and Minimal Ranks of the Common Solution of Some Linear Matrix Equations over an Arbitrary Division Ring with Applications

We establish the formulas of the maximal and minimal ranks of the common solution of certain linear matrix equations A1X = C1, XB2 = C2, A3XB3 = C3 and A4XB4 = C4 over an arbitrary division ring. Corresponding results in some special cases are given. As an application, necessary and sufficient conditions for the invariance of the rank of the common solution mentioned above are presented. Some previously known results can be regarded as special cases of our results.
A Nested Newton-Type Algorithm for Finite Volume Methods Solving Richards' Equation in Mixed Form

A finite volume discretization of the mixed form of Richards' equation leads to a nonlinear numerical model which yields exact local and global mass conservation. The resulting nonlinear system requires sophisticated numerical strategies, especially in a variable saturated flow regime. In this paper a nested, Newton-type algorithm for the discretized Richards' equation is proposed and analyzed. With a judicious choice of the initial guess, the quadratic convergence rate is obtained for any time step size and for all flow regimes.
Formation and eruption of solar prominences

A model for the magnetic field associated with solar prominences is considered. It is shown that flux cancellation at the neutral line of a sheared magnetic arcade leads to the formation of helical field lines which are capable, in principle, of supporting prominence plasma. A numerical method for the computation of force-free, canceling magnetic structures is presented. Starting from an initial potential field we prescribe the motions of magnetic footpoints at the photosphere, with reconnection occurring only at the neutral line. As more and more flux cancels, magnetic flux is transferred from the arcade field to the helical field. Results for a particular model of the photospheric motions are presented. The magnetic structure is found to be stable: the arcade field keeps the helical field tied down at the photosphere. The axis of the helical field moves to larger and larger height, suggestive of prominence eruption. These results suggest that prominence eruptions may be trigered by flux cancellation. 73 refs.
Pulsed magnetic field-induced actuation of Ni–Mn–Ga single crystals

The field-induced actuation of Ni–Mn–Ga single crystals through twin-boundary motion has been demonstrated with magnetic fieldpulses of various intensities lasting 620 μs. It is shown that the complete field-induced strain can be obtained in 250 μs, which implies the possibility of full 6% cycling of Ni–Mn–Ga at 2 kHz, for crystals having dimensions in the range of a few millimeters. The final extension increases with the peak driving force, which is not linear with the field and saturates at 7.85 kOe. An increase of the field beyond the saturation level produces no additional strain but reduces the time for field-induced detwinning.
Measurement of exclusive baryon-antibaryon decays of χcJ mesons

Using a sample of 2.59x10{sup 7} {psi}(2S) decays collected by the CLEO-c detector, we present results of a study of {chi}{sub cJ} (J=0, 1, 2) decays into baryon-antibaryon final states. We present the world's most precise measurements of the {chi}{sub cJ}{yields}pp and {chi}{sub cJ}{yields}{lambda}{lambda} branching fractions, and the first measurements of {chi}{sub c0} decays to other hyperons. These results illuminate the decay mechanism of the {chi}{sub c} states.
Regression Models for Discrete Longitudinal Responses

In this paper, we review analytic methods for regression mod- els for longitudinal categorical responses. We focus on both likelihood- based approaches and non-likelihood approaches to analysing repeated binary responses. In both approaches, interest is focussed primarily on the regression parameters for the marginal expectations of the binary responses. The association or time dependence between the responses is largely regarded as a nuisance characteristic of the data. We consider these approaches for both the complete and incomplete data cases. We describe the generalized estimating equations (GEE) approach, a non-likelihood approach, and some proposed extensions of it. We also discuss likelihood-based approaches that are based on a log-linear repre- sentation of the joint probabilities of the binary responses. We describe how a likelihood-based "mixed parameter" model yields likelihood equa- tions for the regression parameters that are of exactly the same form as the GEE. An outline of the desirable features and drawbacks of each approach is presented. In addition, we provide some comparisons in terms of asymptotic relative efficiency for the complete data case, and in terms of asymptotic bias for the incomplete data case. Finally, we make some recommendations concerning the application of these methods.
Nonuniqueness in the inverse scattering problem

The inverse scattering problem consists of determining the functional form of a scattering potential given the scattering matrix A (k0s, k0s0) for all scattering directions s and one or more values of the wave vector k0s0. In this paper it is shown that within the framework of the first Born approximation the inverse scattering problem as defined above does not possess a unique solution. It is also shown that within the framework of exact (potential) scattering theory the problem does not admit a unique solution given only the scattering matrix for a single fixed value of the wave vector k0s0 as data. The final section in the paper considers scattering experiments using incident fields other than plane waves and where knowledge of the scattered field at all points exterior to the scattering volume is available as data. It is found that, within the framework of exact scattering theory, the data generated by any single such experiment is not sufficient to uniquely specify the scattering potential while, wit.
Experimental study of the effect of gas nature on plasma arc cutting of mild steel

This paper is devoted to the experimental investigation of arc cutting of mild steel using plasmas generated in gas and liquid media. Due to different chemical compositions, the examined media have different thermophysical properties, which affect the properties of the generated plasma and cutting performance. The experiments are performed on 15 mm mild steel plates using commercial equipment at 60 A to approach real operation conditions in application areas. The studied gases are chosen according to recommendations of the world's leading manufacturers of arc cutting equipment for mild steel. Specific differences between plasma gases are discussed from the point of view of properties of the gas and the generated plasma, amount of removed material, kerf shape and overall energy balance of the cutting process. The paper describes the role of exothermic reaction of iron oxidation for oxygen cutting and explains its neglect for liquid cutting. This paper explains the potential of facilitating the cutting process by modification of the plasma gas chemical composition and flow rate.
Magnetic anisotropy of non-interacting collinear nanocrystal-chains

The magnetic anisotropy of linear chains of spherical magnetite nanocrystals was investigated by means of angle-resolved ferromagnetic resonance spectroscopy, in order to determine the different anisotropy contributions. The linear assembly of nanocrystals generates an interaction-induced uniaxial anisotropy, which is nearly an order of magnitude stronger than the intrinsic magnetocrystalline anisotropy of magnetite, and can only exist in magnetic nano-chains, where the easy axes of the nanocrystals are collinear.
Optimal amplification of the Crow instability

A mechanism for promoting the Crow instability in a counter-rotating vortex pair is presented within the framework of linear dynamics. It consists of (i) the creation of a periodic array of vortex rings along the length of the vortices by stretching of vorticity at the leading hyperbolic point of the dipole, and (ii) the deformation of the vortices by the vortex rings leading to the Crow instability. A reduction of the characteristic time of the Crow instability by a factor of roughly 2 can be obtained by this mechanism.
Waring's Problem for Linear Polynomials and Laurent Polynomials

Waring’s problem is about representing any function in a class of functions as a sum of kth powers of nonconstant functions in the same class. We allow complex coefficients in these kind of problems. Consider ∑p1 i=1 fi(z) k = z and ∑p2 i=1 fi(z) k = 1. Suppose that k ≥ 2. Let p1 and p2 be the smallest numbers of functions that give the above identities. W.K. Hayman obtained lower bounds of p1 and p2 for polynomials, entire functions, rational functions and meromorphic functions. First, we consider Waring’s problem for linear polynomials and get p1 = k and p2 = k + 1. Then, we study Waring’s problem for Laurent polynomials and obtain lower bounds of p1 and p2.
Characterization of the Structural and Mechanical Changes of the Biceps Brachii and Gastrocnemius Muscles in the Subacute and Chronic Stage after Stroke

The objective of this study was to characterize the changes of muscle tone, stiffness, and thickness of upper and lower limb muscles in stroke survivors. Forty patients with subacute or chronic stroke and 31 controls were included and measured using myotonometry (MyotonPRO), with multiple site assessments at muscle belly (MB) and musculotendinous (MT) locations of the biceps brachii and gastrocnemius muscles. Muscle thickness (ultrasonography) was obtained for each muscle. Upper and lower limb motor performance was evaluated with the Fugl–Meyer Assessment for Upper Extremity and the Functional Ambulance Category. Overall, muscle tone and stiffness were significantly higher at MT than at MB sites. Among stroke patients, differences between the paretic and nonparetic limb were found for the biceps brachii, with lower muscle tone, stiffness, and thickness of the paretic side (all, p < 0.05). There were weak to moderate correlations between mechanical (myotonometry) and structural (ultrasound) muscular changes, regardless of the post-stroke stage. This suggests that myotonometry and ultrasonography assess similar, although different, constructs and can be combined in the clinical setting. Their discriminative ability between the paretic and nonparetic sides and between participants with and without stroke differs depending on the muscle, the functional level, and the stroke stage.
Ordering n-vertex cacti with matching number q by their spectral radii

Abstract A connected graph G is a cactus if any two of its cycles have at most one common vertex. Denote by the set of n-vertex cacti with matching number q. Huang, Deng and Simić [23] identified the unique graph with the maximum spectral radius among 2q-vertex cacti with perfect matchings. In this paper, as a continuance of it, the largest and second largest spectral radii together with the corresponding graphs among are determined. Consequently, the first two largest spectral radii together with cacti having perfect matchings are also determined.
A Higher-Order Boundary Treatment for Cartesian-Grid Methods

The Euler equations describe the flow phenomena of compressible inviscid gas dynamics. We simulate such flows using a higher-order Cartesian-grid method, together with a special treatment for the cells cut by the boundary of an object. A new method for the treatment of the boundary is described where these cut boundary cells are maintained as whole cells rather than as cut cells, thus avoiding stability problems. The method is second-order accurate in one dimension and higher-order accurate in two dimensions but not strictly conservative; however, we show that this error in the conservation does not lead to spurious phenomena on some representative test calculations. The advantages of the new boundary treatment are that it is higher-order accurate, that it is independent of the applied method, and that it is simple.
Some general ansätze for the Lanczos potential spinor

The Weyl curvature spinor of every four‐dimensional spacetime is derivable from a potential spinor, called the Lanczos potential. In certain special situations the Lanczos spinor has been found explicitly, but there exists no algorithm for finding it in general. Using a modified Newman–Penrose formalism proposed by Wünsch, we study some ansätze as candidates for the Lanczos potential with respect to an arbitrary spin frame. We show under which necessary and sufficient conditions each ansatz will lead to a Lanczos potential of theWeyl spinor. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Multicolor CCD imaging of supergiants in the disk of NGC 253

Using the 3.6 m CTFH, we have obtained B, V, and R CCD images of a large field in the nearby galaxy NGC 253, sampling portions of both the inner and outer disk regions. The data were recorded during conditions of exceptionally good seeing, permitting individual stars to be resolved over a large area of the galaxy. Two-color and color-magnitude diagrams are constructed, and it appears that the majority of the stars we have detected are supergiants of spectral types A, F, and G.
Solid-Fuel Regression Rate Behavior of Vortex Hybrid Rocket Engines

Aseriesofstaticenginee ringswereconductedtoinvestigatethesolid-fuelregressionratebehaviorandoperating characteristicsofvortexhybridrocketengines.Thevortexhybridenginecone gurationischaracterizedbyacoaxial, coswirling, countere owing vortex combustion e eld in a cylindrical fuel port. To generate this e owe eld, oxidizer is injected through a swirl injector located between the aft end of the fuel grain and the inlet to the converging portion of the exit nozzle. Test e rings with thrusts up to 960 N were conducted with gaseous oxygen and hydroxylterminated polybutadiene solid fuel. Average fuel regression rates up to seven times larger than those in similar classical hybrids were measured. Empirical correlations were developed to describe accurately the experimental regression rates over more than an order of magnitude variation in mass e ux. In addition to local mass e ux and oxygeninjectionvelocity,geometricenginevariables,suchasenginecontractionratioand length-to-diameterratio, had a signie cant ine uence on the measured regression rates. Nondimensional regression rate and heat transfer correlations were also developed. Throttling and restart capability were demonstrated. Nomenclature A = cross-sectional area, cm 2 B = blowing parameter cp = isobaric specie c heat, J/kg ¢K D = port diameter, cm Ea = activation energy, kcal/mole G = local mass e ux, kg/m 2 ¢s Ginj = injection mass velocity, kg/m 2 ¢s GO = gaseous oxygen mass e ux, kg/m 2 ¢s
Beyond the Interface: Improved Pulmonary Surfactant-Assisted Drug Delivery through Surface-Associated Structures

Pulmonary surfactant (PS) has been proposed as an efficient drug delivery vehicle for inhaled therapies. Its ability to adsorb and spread interfacially and transport different drugs associated with it has been studied mainly by different surface balance designs, typically interconnecting various compartments by interfacial paper bridges, mimicking in vitro the respiratory air–liquid interface. It has been demonstrated that only a monomolecular surface layer of PS/drug is able to cross this bridge. However, surfactant films are typically organized as multi-layered structures associated with the interface. The aim of this work was to explore the contribution of surface-associated structures to the spreading of PS and the transport of drugs. We have designed a novel vehiculization balance in which donor and recipient compartments are connected by a whole three-dimensional layer of liquid and not only by an interfacial bridge. By combining different surfactant formulations and liposomes with a fluorescent lipid dye and a model hydrophobic drug, budesonide (BUD), we observed that the use of the bridge significantly reduced the transfer of lipids and drug through the air–liquid interface in comparison to what can be spread through a fully open interfacial liquid layer. We conclude that three-dimensional structures connected to the surfactant interfacial film can provide an important additional contribution to interfacial delivery, as they are able to transport significant amounts of lipids and drugs during surfactant spreading.