Miracle-dz/UniFAR-FTUs huggingface dataset:
Antihelium in Cosmic Rays: A New Upper Limit and Its Significance

We have searched for antihelium in the galactic cosmic rays using data obtained on the flight of the Balloon-borne Experiment with a Superconducting Spectrometer (BESS) launched from Lynn Lake, Manitoba, in northern Canada on 1995 July 25. The balloon reached an altitude of 36.5 km with a residual overburden of 5 g cm-2. The total observation time was 12.2 hr with a live-time fraction of 0.61. No antihelium was observed after selections based on dE/dx and event quality cuts at rigidities between 1.6 and 16 GV/c; we infer that 536,420 helium nuclei survived the same cuts. This result leads to an upper limit to the /He abundance ratio of 8.1 × 10-6 (95% confidence level), a factor of 2.7 over the lowest previous limit. Because this limit is for the first time at the level where predicted limits become astrophysically interesting (Ahlen et al.), we have reexamined the transport of cosmic rays in intergalactic space. We show that little can be learned about distant (>10 Mpc) domains of antimatter from a null result.
Induced Phase Transitions of Functional Ceramics: Properties and Applications

This paper reviews the spontaneous polarization of ferroelectric ceramics and its variations with applied electric field, stress and temperature, especially at induced phase transitions. Normally, there are two kinds of field dependence of the induced polarization, the linear and nonlinear dependence. In this paper the nonlinear relationship will be emphasized. The application of these ceramics for underwater transducers, shock wave power generators, pyroelectric energy converters and pyroelectric voltage transformers are listed.
Inversion of experimental data using linearized and binary specialized nonlinear inversion schemes

We deal with an electromagnetic inverse scattering problem where the goal is to characterize dielectric and metallic unknown targets from measurements of the scattered electric fields that result from their interaction with a known interrogating wave in the microwave frequency range. This nonlinear and ill-posed inverse problem is tackled from experimental data collected in a laboratory-controlled experiment led at the Institut Fresnel. Inversion is performed by means of the binary modified gradient method, a nonlinearized iterative technique tailored to the case of homogeneous targets. This method does not always converge towards an acceptable solution if initialization of the unknowns is not carefully performed. The latter is obtained, herein, from diffraction tomography, a linearized solution method which yields in a very fast way a rough estimate of the location, shape and size of the unknown target.
Polarization of radiation in incoherent Thomson scattering by high temperature plasma

The state of polarization of radiation scattered from hot plasma for any given input polarization is obtained by a relativistic derivation. Approximate analytical expressions are obtained for electron temperatures below about 10 keV. The characteristics of the scattered polarization are presented in detail for fully and linearly polarized incident radiation and their implications for the design of experiments are discussed.
Dissociative Attachment in CO and NO

The electron energy dependences of the cross sections and of the ion kinetic energy distributions have been measured for ${\mathrm{O}}^{\ensuremath{-}}$ production from CO and NO. The present apparatus permits total collection measurements as well as kinetic energy analysis and mass identification of the ions produced. It is shown that in CO two reactions contribute to the single peak in the cross section, whereby carbon atoms are produced in their ground state and in their first excited state ($^{1}D$) respectively. The first reaction is predominant, and known from previous work to have a peak cross section of 2.0 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}19}$ ${\mathrm{cm}}^{2}$. Normalized to this, the second reaction is shown to have a peak cross section of 9.5 \ifmmode\times\else\texttimes\fi{} ${10}^{\ensuremath{-}21}$ ${\mathrm{cm}}^{2}$. In NO it is shown that ${\mathrm{O}}^{\ensuremath{-}}$ production proceeds exclusively through the reaction $e+\mathrm{NO}\ensuremath{\rightarrow}{\mathrm{O}}^{\ensuremath{-}}+{\mathrm{N}}^{*}$ where $\mathrm{N}*$ is the first excited state ($^{2}D$). No ${\mathrm{O}}^{\ensuremath{-}}$ ions are observed corresponding to the formation of ground state N. Nor is there any evidence for the production of the second excited state of nitrogen, $\mathrm{N}(^{2}P)$, postulated by Dorman to account for the structure in the attachment cross section.
Numerical method for the modeling of high-gain single-pass cascade stimulated Raman scattering in gases

The nonlinear Maxwell wave equation in the paraxial approximation has been solved with three standard beam propagation methods: finite-difference (FD), finite-element (FE), and spectral (Fourier). The particular case of high-gain single-pass stimulated Raman scattering in gases has been considered because of its relevance in tuning high-power ultraviolet lasers. For weak nonlinear interaction the FD and the FE methods are recognized to be faster than the Fourier method, whereas they are of comparable stability. This situation changes when the gain reaches a certain limit: The numerical dispersion of the FD and FE methods becomes such that only the Fourier method is applicable.
Microstructure Characterization of Asphalt Mixtures with 2- and 3-Point Correlation Functions

ABSTRACT The majority of micromechanics models available in the literature to estimate effective properties of asphalt mixtures are based only on the mechanical properties and the volumetric fraction information of its constituents. However, significant improvements in the prediction of these models can be obtained if higher-order microstructural information provided by n-point correlation functions is included. This paper proposes a simplified algorithm to estimate the 2- and 3-point correlation functions of asphalt mixtures microstructures. The proposed algorithm approximates the correlation functions based on Monte Carlo simulations. Analytical solutions for the 2- and 3-point correlation functions of a heterogeneous material made of penetrable spheres are compared with the approximated functions obtained with the proposed method. The approximated correlation functions are in good agreement with the analytical solutions. In this paper, microstructure characterization of asphalt mixtures is obtained by means of digital processed images and the approximated 2-and 3-point correlation functions.
Plane Wave Scattering By an Array of Bianisotropic Cylinders Enclosed By Another One in an Unbounded Bianisotropic Space: Oblique Incidence

We consider the following scattering problem: An arbitrarily polarized plane wave, propagating in an unbounded bianisotropic space, is obliquely incident on an array of parallel bianisotropic cylinders which are enclosed by another bianisotropic cylinder. The boundary value problem is formulated in terms of a set of two coupled second order differential equations. The solution technique combines the method of separation of variables with the translational addition theorem. The matrix elements of the resulting linear algebraic system are given by single-term analytical expressions. Numerical examples are presented for several cases along with comparisons with previously published results.
Mesh adaption and automatic differentiation in a CAD-free framework for optimal shape design

A new approach for optimal shape design based on a CAD-free framework for shape and unstructured mesh deformations, automatic differentiation for the gradient computation and mesh adaption by metric control in 2D is presented. The CAD-free framework is shown to be particularly convenient for optimization when the mesh connectivities and control space size are variable during optimization. Constrained optimization for a transonic regime has been investigated in both 2D and 3D
Enhanced Transport Currents in Cu-Sheathed MgB2 Wires

Copper-sheathed MgB2 wires, prepared by an in-situ process, were exposed to neutron radiation in order to introduce defects into the superconductor. The high level of disorder (4.6 × 10−2 dpa) leads to a decrease of the transition temperature by more than 4 K, but to an increase of the slope of the irreversibility line, thus resulting in higher irreversibility fields at low temperatures. The transport currents are significantly enhanced at 4.2 K for fields above 2 T.
Decentralized nonlinear robust control of UAVs in close formation

This paper treats the design of a decentralized nonlinear robust control system for formation flying of multiple unmanned aerial vehicles (UAVs). In close formation, it is assumed that vortex of any UAV affects the motion of all the UAVs behind it. The forces produced by these vortices are complex functions of relative position co‐ordinates of the UAVs. In this paper, these forces are treated as unknown functions, which cannot be parameterized. Since the system is not invertible in the wind axes system, a simplified co‐ordinate system obtained from the wind axes system for which the velocity roll (bank angle) is zero, is considered for the design of the control system. A nonlinear robust control system for the separation trajectory control of the wing aircraft in the simplified wind coordinate system is derived. Uncertain functions and unmeasured variables are estimated using a high‐gain observer for the synthesis of the control system. Each wing UAV synthesizes its control law using its own state variables and the relative position of the preceding UAV with respect to the wing UAV. Thus the control system is decentralized since each UAV has to communicate (depending on sensors for position measurement) with at most one (preceding) UAV, and no data transmission from the remaining vehicles is required. Simulation results for two UAVs are presented which show precise separation trajectory control of each wing UAV in spite of the presence of unknown and unstructured vortex forces, while the lead aircraft maneuvers. Furthermore, these results confirm that when the wing aircraft is positioned properly in the vortex of the lead aircraft, it experiences reduction in its required flight power. Copyright © 2003 John Wiley & Sons, Ltd.
A contrast source inversion method

This paper describes a simple algorithm for reconstructing the complex index of refraction of a bounded object immersed in a known background from a knowledge of how the object scatters known incident radiation. The method described here is versatile accommodating both spatially and frequency varying incident fields and allowing a priori information about the scatterer to be introduced in a simple fashion. Numerical results show that this new algorithm outperforms the modified gradient approach which until now has been one of the most effective reconstruction algorithms available.
A Measurement of the Angular Power Spectrum of the Cosmic Microwave Background with a Long Duration Balloon-borne Receiver

This thesis describes BOOMERANG; a balloon-borne telescope and receiver designed to map the Cosmic Microwave Background (CMB) at a resolution of 10' from the Long Duration Balloon (LDB) platform. The millimeter-wave receiver employs new technology in bolometers, readout electronics, cold re-imaging optics, millimeter-wave filters, and cryogenics to obtain high sensitivity to CMB anisotropy. Sixteen detectors observe in 4 spectral bands centered at 90, 150, 240 and 400 GHz. The wide frequency coverage, the long flight duration, the optical design and the observing strategy all provide strong rejection of systematic effects. We report the in-flight performance of the instrument during a short test flight from Palestine, Texas, that mapped 230 square degrees and during a 10.5 day stratospheric balloon flight launched from McMurdo Station, Antarctica, that mapped ~ 2000 square degrees of the sky. The Antarctic data yielded a measurement of the angular power spectrum of the CMB between 50
Class of error metrics for gray-scale image comparison

We suggest a new approach to assess discrepancies between grey- scale images. Such numerical discrepancy measures are usually called error metrics, since they provide a numerical assessment of the dissimilarity between two images. The suggested approach is based on the idea that each upper semicontinuous grey-scale image f corresponds to a random closed set FU equals {x: f(x) >= U} which appear if the image is thresholded as a randomly chosen level U. Then distance between distributions of random sets (which generalize the concept of probability metric distances for random variables) serve as error metrics for grey- scale images. These metrics generalize the famous constructs like uniform distance between distributions of random variables and Monge-Kantorovich metric for distribution functions. However, instead of distribution functions of random variables, their definitions refer to capacity functionals of the corresponding random closed sets. Several general mathematical constructions for such metrics are presented, compared and examined from both theoretical and practical viewpoints. Among wide range of applications of error metrics in image processing we concentrate on their use to assess performance of image restoration algorithms and in Bayesian image reconstruction. In the latter case we focus on one particular error metric and show how it can be used in the context of Bayesian image restoration, where the `true' image is unknown, but is assumed to have a certain prior distribution.
On the Composition of Unimodal Distributions

A distribution function is called strong unimodal if its composition with any unimodal distribution function is unimodal.The following theorem is proved:For a proper unimodal distribution $F(x)$ to be strong unimodal, it is necessary and sufficient that the function $F(x)$ be continuous, and the function log $F'(x)$ be concave at a set of points where neither the right nor the left derivative of the function $F(x)$ is equal to zero.
Enhanced THz Radiation from Femtosecond Laser Pulse Irradiated InAs Clean Surface

A significant enhancement of THz radiation from an InAs clean (100) surface is observed with irradiation of femtosecond laser pulses at 50 K. Due to the surface cleaning and cooling temperature, the THz-radiation intensity from the InAs clean (100) surface at 50 K becomes to 10 times larger than that from an uncleaned surface at room temperature.
Filtering and smoothing in an H/sup infinity / setting

Consideration is given to the problems of filtering and smoothing for linear systems in an H/sup infinity / setting, i.e. the plant and measurement noises have bounded energies (are in L/sub 2/), but are otherwise arbitrary. Two distinct situations for the initial condition of the system are considered: in one case the initial condition is assumed known; in the other case it is not known, but the initial condition, the plant, and the measurement noise are in some weighted ball of R/sup n/*L/sub 2/. Both finite-horizon and infinite-horizon cases are considered. The authors present necessary and sufficient conditions for the existence of estimators (both filters and smoothers) that achieved a prescribed performance bound and develop algorithms that result in performance within the bounds. They also present the optimal smoother. The approach uses basic quadratic optimization theory in a time-domain setting, as a consequence of which time-varying and time-invariant linear systems can be considered with equal ease. <<ETX>>
Zonal Gradients in the Lower Atmosphere and Upper Ocean across the Windward Antilles during Midsummer 2012

AbstractThis observational study examines zonal gradients in the lower atmosphere and upper ocean across the windward Antilles during midsummer 2012. While earlier work reported on meridional confluence, here the focus is on the zonal enrichment of trade winds by upstream shallow seas and islands. Intercomparisons along 18.2°N are made between modern reanalysis and satellite estimates, and coastal station, moored buoy, aircraft, and radiosonde observations for one case and as a June–July 2012 average. Mean gradients per 100 km east of Puerto Rico were 0.2 g kg−1 for 925-hPa specific humidity, 0.16°C for SST, 0.01 m for sea level, and 2.0 × 10−3 g kg−1 for cloud water. Zonal changes in the lower atmosphere occur in three stages: 1) Atlantic, where westward ocean currents, strong trade winds, and subsidence prevail; 2) Antilles, where ocean currents diminish and sea temperatures increase; and 3) island, where trade winds abate [−1 m s−1 (100 km)−1] and diurnal evapotranspiration greater than 10 mm day−1 off.
Estimation of latent ability using a response pattern of graded scores

Estimation of latent ability using the entire response pattern of free-response items is discussed, first in the general case and then in the case where the items are scored in a graded way, especially when the thinking process required for solving each item is assumed to be homogeneous. The maximum likelihood estimator, the Bayes modal estimator, and the Bayes estimator obtained by using the mean-square error multiplied by the density function of the latent variate as the loss function are taken as our estimators. Sufficient conditions for the existence of a unique maximum likelihood estimator and a unique Bayes modal estimator are formulated with respect to an individual item rather than with respect to a whole set of items, which are useful especially in the situation where we are free to choose optimal items for a particular examinee out of the item library in which a sufficient number of items are stored with reliable quality controls. Advantages of the present methods are investigated by comparing them with those which make use of conventional dichotomous items or test scores, theoretically as well as empirically, in terms of the amounts of information, the standard errors of estimators, and the mean-square errors of estimators. The utility of the Bayes modal estimator as a computational compromise for the Bayes estimator is also discussed and observed. The relationship between the formula for the item characteristic function and the philosophy of scoring is observed with respect to dichotomous items.
Seismic trace interpolation in the F-X domain

Interpolation of seismic traces is an effective means of improving migration when the data set exhibits spatial aliasing. A major difficulty of standard interpolation methods is that they depend on the degree of reliability with which the various geological events can be separated. In this respect, a multichannel interpolation method is described which requires neither a priori knowledge of the directions of lateral coherence of the events, nor estimation of these directions.The method is based on the fact that linear events present in a section made of equally spaced traces may be interpolated exactly, regardless of the original spatial interval, without any attempt to determine their true dips. The predictability of linear events in the f-x domain allows the missing traces to be expressed as the output of a linear system, the input of which consists of the recorded traces. The interpolation operator is obtained by solving a set of linear equations whose coefficients depend only on the spectrum of the spatial prediction filter defined by the recorded traces.Synthetic examples show that this method is insensitive to random noise and that it correctly handles curvatures and lateral amplitude variations. Assessment of the method with a real data set shows that the interpolation yields an improved migrated section.
Dielectric materials, design, and realization

It has been the dream of many scientists to create polymeric materials which exhibit simultaneously high dielectric permittivity, low glass transition temperature, and excellent elastic properties. Such materials would be a highly attractive dielectric in electromechanical transducers. Within this topic we are focusing on silicones because of their excellent elastic properties over wide temperature and frequency ranges combined with low glass transition temperatures. To increase their low permittivity, we followed different approaches which include: blending the matrix with highly polarizable conductive and polar nanofillers and chemical modification with polar side groups. This presentation will show the advantages and disadvantages of the two strategies we have been following and will provide an assessment of their future potential.
The Scale-Linkage Algorithm: Construction of a Universal Criterion Scale for Families of Institutions

A new approach to the construction of a universal criterion scale for a family of comparable institutions is presented. Proceeding through the development of a sequence of paired calibrations determined by a hierarchical clustering algorithm, the method does not rely on covariate information such as scores on common examinations. As such it is perfectly suited to be employed in aggregated validity studies that combine data from many institutions. Such applications are explored in our companion paper, “Validity Studies Based on a Universal Criterion Scale” (in this issue). The procedure is illustrated with data from American Law Schools.
PRECISE NUMERICAL DETERMINATION OF THE SUPERCONDUCTING EXPONENT OF PERCOLATION IN THREE DIMENSIONS

We present data obtained on the special purpose computer "Percola" determining the exponent $\frac{8}{\nu}$ of the random mixture of superconducting and normal conducting elements at the percolation threshold. The extrapolation is done for bond and site percolation and gives $\frac{8}{\nu} =0.835\pm 0.005$ with a correction exponent ω = 1.85 ± 0.20.
A Kantian View of the City: A Factorial-Ecology Experiment in Space and Time

This paper reports on a factorial-ecology experiment using ‘space—time units’. City space is divided ten ways and time eight ways to produce a set of eighty space—time units. Data is artificially created for these eighty units covering twenty-two variables. From a factor analysis of this data set, seven factors are extracted and interpreted by using the input variables and the space—time framework.
Properties of Soliton-Transported Bio-energy in α-Helix Protein Molecules with Three Channels

We study numerically the propagating properties of soliton-transported bio-energy excited in the alpha-helix protein molecules with three channels in the cases of the short-time and long-time motions and its features of collision at temperature T = 0 and biological temperature T = 300 K by the dynamic equations in the improved Davydov theory and fourth-order Runge-Kutta method, respectively. From these simulation experiments we see that the new solitons in the improved model can move without dispersion at a constant speed retaining its shape and energy in the cases of motion of both short-time or T = 0 and long time or T = 300 K and can go through each other without scattering in their collisions. In these cases its lifetime is, at least, 120 ps at 300 K, in which the soliton can travel over about 700 amino acid residues. This result is consistent with analytic result obtained by quantum perturbed theory in this model. In the meanwhile, the influences of structure disorder of a-helix protein molecules, including the inhomogeneous distribution of amino acids with different masses and fluctuations of spring constant, dipole-dipole interaction, exciton-phonon coupling constant and diagonal disorder, on the solitons are also studied by the fourth-order Runge-Kutta method. The results show that the soliton still is very robust against the structure disorders and thermal perturbation of proteins at biological temperature 300 K. Therefore we can conclude that the new soliton in the a-helix protein molecules with three channels is a possible carrier of bio-energy transport and the improved model is possibly a candidate for the mechanism of this transport.