Miracle-dz/UniFAR-FTUs huggingface dataset:
Annealing kinetics of thin permalloy films

Low-temperature (250-397°C) annealing was found to cause a large decrease in the resistivity of radio-frequency sputter-deposited thin (≤ 500 A) Permalloy films. A transmission electron microscope was used to investigate a probable microstructural change occurring during the annealing. It was found that the low-temperature annealing induced considerable grain growth in these films. Furthermore, an electron diffraction analysis has shown that this grain growth was accompanied by the formation of the ordered phase (Ni 3 Fe). The use of dark-field imaging revealed that the small ordered region appears to be formed around the disordered regions via a grain-boundary diffusion mechanism. The observed resistivity decrease was proposed to occur by the structural ordering as a result of the annealing. The measured activation energy for this process was 0.72 eV. This activation energy appears to be associated with the grain boundary migration of excess vacancies trapped during film formation.
On the Surface Response of Solar Giant Cells

On considere le desaccord existant entre les theories de la convection de cellules geantes, prevoyant des vitesses d'ecoulement typiques de l'ordre de 100 m s −1 , et les observations qui donnent une limite superieure d'environ 10 m•s −1 a la vitesse est-ouest a la surface solaire
Numerical study of the Eulerian-Lagrangian formulation of the Navier-Stokes equations

An Euler–Lagrangian analysis of the Navier–Stokes equations is performed with use of numerical simulations. On this basis we propose a new method for capturing vortex reconnection. It is found that the diffusive Lagrangian map becomes noninvertible under time evolution and requires resetting for its calculation. This sets a time scale and its frequent resetting corresponds to vortex reconnection. Another time scale defined by the connection coefficients, responsible for noncommutativity of Euler and Euler–Lagrange derivatives, is shown to be on the same order during reconnection. This introduces a novel singular perturbation problem of connection anomaly underlying reconnection.
Variational Principle for Saturated Magnetoelastic Insulators

In a previous paper, a system of nonlinear differential equations and boundary conditions governing the macroscopic behavior of arbitrarily anisotropic nonconducting magnetically saturated media undergoing large deformations, was derived. The derivation utilized the classical procedure of defining field vectors and determining the equations relating them by applying energy and momentum conservation theorems. The macroscopic effect of the quantum mechanical exchange interaction was included as was dissipation and the associated thermodynamics. The magnetic field was assumed to be quasistationary. In this paper a variational principle is presented, which is shown to yield the aforementioned system of equations and boundary conditions in the absence of dissipation and heat flow.
Wetting and interfacial order at nematic free surfaces

We apply a density-functional theory to the free surface of a model liquid crystal, to investigate the orientational order at the nematic free surface of systems exhibiting orientational wetting at the isotropic liquid-vapour interface. It is shown that the theory accounts for the growth of the surface ordered layer which develops at the nematic-vapour interface, as the temperature increases up to the triple point, as was recently reported for 4-cyano-4'-n-alkyl-biphenyls. We have found a correlation between the growth of this layer and the non-monotonic temperature dependence of the interfacial tension below the triple point. The theoretical results are in excellent agreement with the results for 8CB.
Standard solar model

A set of solar models have been constructed, each based on a single modification to the physics of a reference solar model. In addition, a model combining several of the improvements has been calculated to provide a best solar model. Improvements were made to the nuclear reaction rates, the equation of state, the opacities, and the treatment of the atmosphere. The impact on both the structure and the frequencies of the low-l p-modes of the model to these improvements are discussed. It is found that the combined solar model, which is based on the best physics available (and does not contain any ad hoc assumptions), reproduces the observed oscillation spectrum (for low-l) within the errors associated with the uncertainties in the model physics (primarily opacities).
Internal model control and process uncertainty: mapping uncertainty regions for SISO controller design

Abstract A complete SISO controller design technique is presented that allows robust controller design in the face of process uncertainty. Process-uncertainty descriptions with meaningful physical interpretations are compatible with the technique. A test for robust performance can be applied when the process is described by a transfer function with real parameter variations. First a method is presented for locating all possible complex variations of a transfer function resulting from real parameter uncertainties. The possible variations are pictured as model uncertainty regions on the complex plane. Next a controller design technique based on the internal model control structure is outlined. The controller is used to map the process uncertainty regions to the Nyquist plane for stability and performance analysis. The region-mapping technique offers a unique opportunity to compare robust performance of PID and Smith Predictor controllers. Finally, applications of the proposed technique to structured singula.
Effect of impurity incorporation on emission wavelength in cathodoluminescence spectrum image study of GaN pyramids grown by selective area epitaxy

Metal-organic chemical vapor deposition has been used for selective epitaxy of GaN pyramids ranging in size from over 1μm to 500 nm in length at the base. Pyramids are terminated by {11¯01} crystal facets. The optical properties of the pyramids are investigated by cathodoluminescence (CL) in a scanning electron microscope. CL spectrum imaging reveals the pyramid apices to emit light at ∼363.4 nm corresponding to the emission wavelength of relaxed GaN. As the CL excitation is moved away from the apex a systematic redshift is observed. The redshift is ∼4 nm for pyramids with 3 μm base dimension and ∼2 nm for the 500 nm pyramids. The shift is attributed to diffusion of silicon and oxygen into the GaN pyramids due to SiO2 mask decomposition with negligible contribution from stress. The observations are backed by finite element simulations of diffusion and stress.
La protection de l'emploi des travailleurs Âgés en France: une étude de la contribution Delalande

Cet article quantifie les effets contradictoires sur l'emploi de la contribution Delalande, taxe sur le licenciement des seniors, dans sa version initiale de 1987. Le modele predit une reduction du taux de chomage moyen des plus de 50 ans. Meme si le chomage augmente pour les travailleurs de 50-54 ans, non proteges par la contribution, cet effet est plus que compense par la forte baisse du chomage apres 55 ans.
Mohr‐Coulomb Yield Criterion in Rock Plastic Mechanics

Conventional Mohr-Coulomb strength criterion only describing the relationship between normal stress and shear stress on the failure surface at the peak strength is used as a criterion to determine whether the beginning of rock's failure. This study extends the concept of the Mohr-Coulomb strength criterion by suggesting that the Mohr-Coulomb yield criterion can express the stress relationship of strain and stress of failure surface under various stress states after plastic deformation occurs. Based on experimental studies, an experiment approach which employs triaxial compression testing data to determine plastic parameters с and φ which vary with the internal variable κ was established, and parameter expression used to assess the accuracy of isotropic modeling and some testing results were given. The Mohr-Coulomb yield criterion of isotropic hardening or softening, in which stress-strain curves of whole process is simplified into a four-line model using initial, peak and remnant parameters of rock, is more applicable than the trilinear model by Toshikazu. The results of this study provides theoretical and experimental basis for engineering and geological numerical simulation, thus being of instructive importance.
An Improved Method for Differential Photometry

We developed a method to improve the conventional differential photometry by using many auxiliary stars to reduce noise in the reference light curve, which is used to calibrate the light curve of the target star. The data used in this study are taken with the Taiwan Automated Telescope network. The light curves of two δ Scuti, HD 163032 and V830 Her, are shown here as examples. The results are compared with four other methods: conventional differential photometry; ensemble photometry; the method of Tamuz, Mazeh, & Zucker; and trend filtering algorithm. The light curve computed with our method is smoother than the other four methods, while preserving the pulsational signals. The mode frequencies determined from the light curve from our method also has a higher S/N and lower error in comparison with other methods.
Astronomical Applications Of Grazing Incidence Telescopes With Polynomial Surfaces

We have examined the claim that grazing incidence telescopes having surfaces described by generalized equations have image characteristics superior to those of the paraboloid-hyperboloid and Wolter-Schwarzschild configurations. With emphasis on specific applications in solar and cosmic X-ray/EUV astronomy, raytracing has shown that in many cases there is no advantage in the polynomial design, and in those cases where advantages are theoretically to be expected, the advantages are outweighed by practical considerations.
Matching Stellar Models to Oscillation Data

We describe a method to match stellar models to a set of low-l p-mode oscillation frequencies. The method provides a quality of fit measure similar to that obtained from a χ2 fit. With a sufficiently dense grid of stellar models, the method can determine the best-fitting model to the oscillation data as constrained solely by the oscillation data. That is to say, the method can be used to constrain the mass, age, composition, surface temperature, and luminosity of a star from the oscillation data. We evaluate the method on solar data and apply the method to the recently observed oscillation data for α Cen and α UMa.
Low frequency scattering simulation of homogeneous objects in layered medium by Muller formed SIE

ABSTRACT This paper presents a novel approach to accurately simulate the low frequency electromagnetic scattering of a homogeneous dielectric object in layered medium. The N-Muller surface integral equation (SIE) is utilized for accurate electromagnetic modeling at low frequency with a properly designed coefficient to cancel frequency singularity. Matrix-friendly layered medium Green’s functions are adopted and integrated into SIE to account for the effects of the inhomogeneous background. By using Galerkin method and rooftop basis functions, a well-conditioned impedance matrix is obtained and a rapidly converging iterative solution is achieved for low frequencies. Numerical results are provided to validate the proposed method and investigate its properties.
Physics Basis of a Fusion Development Facility Utilizing the Tokamak Approach

Abstract The objective of the Fusion Development Facility (FDF) under consideration is to carry forward advanced tokamak physics for optimization of fusion reactors and enable development of fusion’s energy applications. A concept of FDF based on the tokamak approach with conservative expressions of advanced physics and nonsuperconducting magnet technology is presented. It is envisioned to nominally provide 2 MW/m2 of neutron wall loading and operate continuously for up to 2 weeks as required for fusion nuclear component research and development. FDF will have tritium breeding capability with a goal of addressing the tritium self-sufficiency issue for fusion energy. A zero-dimensional system study using extrapolations of current physics and technology is used to optimize FDF for reasonable power consumption and moderate size. It projects a device that is between the DIII-D tokamak (major radius 1.8 m) [J. L. Luxon, Nucl. Fusion, Vol. 42, p. 614 (2002)] and the Joint European Torus (major radius 3 m) [P. H. Rebut, R. J. Bickerton, and B. E. Keen, Nucl. Fusion, Vol. 25, p. 1011 (1985)] in size, with an aspect ratio A of 3.5 and a fusion gain Q of 2 to 5. Theory-based stability and transport modeling is used to complement the system study and to address physics issues related to specific design points. It is demonstrated that the FDF magnetohydrodynamic stability limits can be readily met with conservative stabilizing conducting wall placement. Transport analysis using a drift-wave-based model with an edge boundary condition consistent with the pedestal stability limit indicates that the FDF confinement requirement can also be readily satisfied. A surprising finding is that the toroidal Alfvén eigenmodes are stabilized by strong ion Landau damping. Analysis of vertical stability control indicates that the basis configuration with an elongation κx [approximately] 2.35 can be controlled using a power supply technology similar to that used in DIII-D. Peak heat fluxes to the divertor are somewhat lower than those of ITER [R. Aymar, P. Barabaschi, and Y. Shimomura, Plasma Phys. Control. Fusion, Vol. 44, p. 519 (2002)], but FDF will operate with a higher duty factor.
Study on sound source localization inside a structure using a domain transfer model for real-world adaption of a trained model

Sound source localization (SSL) is important to reduce noise of products such as machinery and electrical appliances. Currently, SSL methods have been proposed that use the correlation of time-frequency signals of sound waves observed by multiple microphones. However, the application of these SSL methods are limited to the case where the acoustic signals can be directly observed. In the case of estimating the location of a sound source inside a structure from outside the structure, these methods are not applicable because the acoustic signal is observed as indirect sound. An SSL method using deep neural network (DNN) and computer-aided engineering (CAE) was proposed to estimate sound sources inside structures. This method successfully estimates the location of sound sources inside a structure from signals observed by accelerometers installed on the outer surface of the structure in both CAE and real domains. Nevertheless, the proposed method still has the challenge of adapting DNNs trained in CAE domain to real domain. In this research, deep convolution auto-encoder (DCAE) was used as a domain transformation model built from CAE and actual experimental data. DCAE contributed to the improvement of the SSL performance of the trained DNN over the baseline.
The application of k-space in medical ultrasound

K-space is a frequency domain description of ultrasonic imaging systems and targets which can be used to gain insight into their interaction during image formation. Although originally proposed as a technique for the analysis of imaging problems involving anisotropic scattering, the authors have found it useful as a general analysis tool. They present analytical and conceptual techniques for estimating the k-space representation of imaging systems with arbitrary transmit and receive array geometries and apodizations. The authors describe simple graphical methods of estimating the first and second order characteristics of speckle formed using different imaging geometries. They also present examples utilizing k-space to gain intuition about the performance of spatial and frequency compounding and to describe the impact of several synthetic aperture geometries on beam forming and speckle statistics. The authors present the Van Cittert Zernike Theorem in k-space and discuss techniques which can be used to improve echo correlation.
Emission Spectroscopic Measurements with an Optical Probe in the NASA Ames IHF Arc Jet Facility

An optical probe was designed to measure radiation (from inside the arc heater) incident on a test sample immersed in the arc-heated stream. Currently, only crude estimates are available for this incident radiation. Unlike efforts of the past, where the probe line of sight was inclined to the nozzle centerline, the present development focuses on having the probe line of sight coincide with the nozzle centerline. A fiber-coupled spectrometer was used to measure the spectral distribution of incident radiation in the wavelength range of 225 to 900 nm. The radiation heat flux in this wavelength range was determined by integration of measured emission spectral intensity calibrated to incident irradiance from an integrating sphere. Two arc-heater conditions, corresponding to stream bulk enthalpy levels of 12 and 22 MJ/kg, were investigated in the 13-inch diameter nozzle of the Interaction Heating Facility at NASA Ames Research Center. With the probe placed at a distance of 10 inches from the nozzle exit plane, total radiative heat fluxes were measured to be 3.3 and 8.4 W/sq cm for the 12 and 22 MJ/kg conditions, respectively. About 17% of these radiative fluxes were due to bound-bound radiation from atoms and molecules, while the remaining 83% could be attributed to continua (bound-free and/or free-free). A comparison with spectral simulation based on CFD solutions for the arc-heater flow field and with spectroscopic measurements in the plenum region indicates that more than 95% of the measured radiation is generated in the arc region. The total radiative heat flux from the line radiation could increase by a factor of two through contributions from wavelengths outside the measured range, i.e., from the vacuum ultraviolet (wavelengths less than 225 nm) and the infrared (wavelengths greater than 900 nm). An extrapolation of the continuum radiation to these two wavelength regions was not attempted. In the tested configuration, the measured radiative heat flux accounts for only about 1.4% of the nominal heat flux on a flat face model and therefore is considered negligible. In the 6-inch diameter nozzle, on account of shorter path lengths, the radiation heat flux could be significant. Therefore, future tests in the 6-inch nozzle will have radiometers in addition to the optical probe.
Verification and Calibration of Neighborhood and Object-Based Probabilistic Precipitation Forecasts from a Multimodel Convection-Allowing Ensemble

AbstractNeighborhood and object-based probabilistic precipitation forecasts from a convection-allowing ensemble are verified and calibrated. Calibration methods include logistic regression, one- and two-parameter reliability-based calibration, and cumulative distribution function (CDF)-based bias adjustment. Newly proposed object-based probabilistic forecasts for the occurrence of a forecast object are derived from the percentage of ensemble members with a matching object. Verification and calibration of single- and multimodel subensembles are performed to explore the effect of using multiple models.The uncalibrated neighborhood-based probabilistic forecasts have skill minima during the afternoon convective maximum. Calibration generally improves the skill, especially during the skill minima, resulting in positive skill. In general all calibration methods perform similarly, with a slight advantage of logistic regression (one-parameter reliability based) calibration for 1-h (6 h) accumulations.The uncalibr.
Periodic boundaries of metamaterials: eigen regimes and resonant radiation

The paper is focused on the study of eigen surface waves of the periodic interfaces of metamaterials. A wide range of numerical experiments is performed on the basis of an accurate solution to the eigen boundary value problem. The peculiarities of eigen waves in dispersive media are revealed. The results obtained in the study help in the understanding of the nature of the diverse types of electromagnetic wave resonant transformation by the periodic surfaces of metamaterials.
Generalized Fermat-Mersenne number theoretic transform

A generalization of the Fermat and Mersenne number transform is suggested. The transforms are defined over finite fields and rings. This paper establishes the conditions necessary for these numbers to be prime. The length of the transforms is a highly composite number. An algorithm for finding primitive roots of unity is also discussed. The proposed transforms are characterized by respectable combinations of transform length, dynamic range and computational efficiency and can be used for fast convolution of integer sequences. >
Approximation Formulae for Estimation of Waiting-Time in Multiple-Channel Queueing System

This article deals with two approximation formulae for estimation of Wq<, mean waiting-time in a M/Ek/R queueing system. It is shown how Wq< for the multiple-channel system with λ = λ, μ = μ is approximately Rth part of Wq-, mean waiting-time in a single-channel system with λ = λ/R, μ = μ. A second approximation applies the exact ratio W</W- for M/M/R and M/M/1-systems to general M/Ek/R-systems This is particularly illustrated in the case of M/M/R and M/D/R-systems.
COMPLEXITY OF FIRST-ORDER METHODS FOR DIFFERENTIABLE CONVEX OPTIMIZATION

This is a short tutorial on complexity studies for differentiable convex optimization. A complexity study is made for a class of problems, an "oracle" that obtains information about the problem at a given point, and a stopping rule for algorithms. These three items compose a scheme, for which we study the performance of algorithms and problem complexity. Our problem classes will be quadratic minimization and convex minimization in ℝn. The oracle will always be first order. We study the performance of steepest descent and Krylov spacemethods for quadratic function minimization and Nesterov’s approach to the minimization of differentiable convex functions.
Nonlinear features for damage detection on large civil structures due to earthquakes

This article proposes the degree of nonlinearity as a feature for damage detection on large civil structures due to earthquakes. The degree of nonlinearity, which is a numerical value, represents how nonlinear structures behave during earthquakes. The degree of nonlinearity is computed directly from the data of the ground motion and vibration of the structure. The computation of the degree of nonlinearity uses a Hilbert transform and does not require any other nonlinear structural or mathematical models. Therefore, the damage detection process is very fast. Thus, an immediate decision about the condition of structures after strong earthquakes is possible. This article shows theoretically that a plot between the degree of nonlinearity against the magnitude of the ground motion represents the behavior of a structure. This plot is considered the signature of that structure. A structure that is healthy will have its specific healthy signature. If a new earthquake strikes and the new degree of nonlinearity deviates from its healthy signature, the structure may be damaged by that earthquake. To verify the validity of the degree of nonlinearity, numerical studies of nonlinear systems are presented. Although the application of degree of nonlinearity on a real civil structure is still not totally conclusive due to the limitation of data, the results from currently available data are encouraging. With more investigation, the degree of nonlinearity could be an additional or alternative feature for vibration-based structural health monitoring.