Miracle-dz/UniFAR-FTUs huggingface dataset:
Photon-counting techniques with silicon avalanche photodiodes

Silicon avalanche photodiodes (APD) have been used for photon counting for a number of years. This paper reviews their properties and the associated electronics required for photon counting in the Geiger mode. Significant improvements are reported in overall photon detection efficiencies (approaching 75% at 633 nm), and timing jitter (under 200 ps) achieved at high over-voltages (20 - 30 V). Results obtained using an active-mode fast quench circuit capable of switching over-voltages as high as 20 V (giving photon detection efficiencies in the 50% range), are reported with a dead-time of less than 50 ns. Larger diodes (up to 1 mm diameter), usable in the Geiger mode, which have quantum efficiencies over 80% in the 500 - 800 nm range also are reported.
SU‐E‐I‐128: Evaluation of Magnetic Resonance Phase Data of Projection and 2‐D FLASH Acquisition to Estimate the AIF

Purpose: Dynamic Contrast Enhanced Magnetic Resonance Imaging (DCE‐ MRI) is a technique that non‐invasively collects data related to the vasculature of tissue. Quantitative information is derived from the time course concentration of contrast agent in a supplying vessel, known as the arterial input function (AIF). The AIF should have a high temporal resolution, but it often compromises spatial resolution. The phase of MRI signal varies linearly with the concentration of a contrast agent, is independent of the hematocrit and is expected to have an increased signal to noise ratio (SNR) when compared to magnitude based data. The use of phase data from projection images satisfies the requirement for high temporal resolution and may be used to reconstruct a 2D image if projected along different axes. Methods: Data was collected using a 7.0 T Bruker MRI system. 1‐D Projection and 2‐D FLASH images were collected on a phantom for varying concentrations of Gadolinium. Phase information was determined directly from the free induction decay (FID) and unwrapped where appropriate. Results: Calibration of the phase data (2‐D FLASH acquisition) verified that the phase increased linearly with the concentration of contrast agent with a slope of (1.183 ± 0.015) rad/mM. A small phase drift was present ((0.014± 0.019) rad/100 min), but had neglible impact on the calibration curve. The concentration of contrast agent as determined from the projection data was in good agreement with the 2D analysis with a slope of (1.187 ± 0.027) rad/mM. Conclusions: Projection based imaging will significantly increase the temporal resolution of DCE‐MRI studies. The linear relationship between the phase and concentration of contrast agent was consistent between the 2‐D FLASH and projection acquisitions. The results of this study suggest that projection based imaging may be used to accurately estimate the AIF.
Sliding order and sliding accuracy in sliding mode control

The synthesis of a control algorithm that stirs a nonlinear system to a given manifold and keeps it within this constraint is considered. Usually, what is called sliding mode is employed in such synthesis. This sliding mode is characterized, in practice, by a high-frequency switching of the control. It turns out that the deviation of the system from its prescribed constraints (sliding accuracy) is proportional to the switching time delay. A new class of sliding modes and algorithms is presented and the concept of sliding mode order is introduced. These algorithms feature a bounded control continuously depending on time, with discontinuities only in the control derivative. It is also shown that the sliding accuracy is proportional to the square of the switching time delay.
Theoretical study on the strain dependence of the magnetic anisotropy of X/Co(X=Pt, Cu, Ag, and Au) metallic multilayers

A first‐principles calculation of the magnetic anisotropy energies of X/Co (X=Pt, Cu, Ag and Au) metallic multilayers has been performed to investigate the effect of strain on the magnetic anisotropy. It is successfully predicted that Pt/Co and Au/Co multilayers exhibit perpendicular magnetic anisotropies in accordance with experiments. The strength of the hybridization of electronic states at the interface determines the relative position of the Fermi energy to the local density of states (LDOS) of ‖m‖=2 character of Co d electrons of minority spin. If the LDOS of ‖m‖=2 character is large at the Fermi energy, a system shows a perpendicular anisotropy. The anisotropy energies of all the systems increase as a function of interatomic distance in the in‐plane direction. The magneto‐elastic constants are more than twice the value of pure Co. The origin of this large value is explained in terms of the change of relative position of the Fermi level to that of the LDOS of ‖m‖=2 character as the value of strain i.
The Time Variability of the Ultraviolet Continuum and Lyman-Alpha in 3C 273

This article presents the light curve of the ultraviolet (UV) continuum flux and of the Lyα emission line of 3C 273 between 1978 and 1992.5. It also presents evidence for a quantitative difference between nearby Seyfert 1 and the quasar 3C 273 regarding the response of the emission lines to UV continuum flux variations. In contrast to what is observed in nearby Seyfert galaxies, the Lyα line in 3C 273 does not significantly respond to flux variations of the continuum by a factor 2. The largest excursion (minimum or maximum) of the Lyα intensity is no more than 8% from the local mean, while the 1 σ error on the Lyα intensity is 5%
Local Adaptivity of Kernel Estimates with Plug‐in Local Bandwidth Selectors

In non‐parametric function estimation selection of a smoothing parameter is one of the most important issues. The performance of smoothing techniques depends highly on the choice of this parameter. Preferably the bandwidth should be determined via a data‐driven procedure. In this paper we consider kernel estimators in a white noise model, and investigate whether locally adaptive plug‐in bandwidths can achieve optimal global rates of convergence. We consider various classes of functions: Sobolev classes, bounded variation function classes, classes of convex functions and classes of monotone functions. We study the situations of pilot estimation with oversmoothing and without oversmoothing. Our main finding is that simple local plug‐in bandwidth selectors can adapt to spatial inhomogeneity of the regression function as long as there are no local oscillations of high frequency. We establish the pointwise asymptotic distribution of the regression estimator with local plug‐in bandwidth.
The effect of neutron irradiation upon the superconducting critical temperature of some transition‐metal carbides, nitrides, and carbonitrides

Samples of TiN, NbC, and Nb(CN) have been irradiated to various neutron doses in the Brookhaven High Flux Beam Reactor. Their superconducting critical temperatures are reduced at a rate which is much less than that for similarly irradiated high‐Tc A15 superconductors. A dose of 1.5×1020 n/cm2 (E≳1 MeV) causes a reduction in Tc of 6–27%. This reduction may be explained in terms of the production of metal‐lattice vacancies.
High-resolution passive microwave observations of convective systems over the tropical Pacific ocean

Abstract This paper presents high-resolution passive microwave measurements obtained in the western Pacific warm pool region. These measurements represent the most comprehensive such observations of convection over the tropical oceans to date, and were obtained from the Advanced Microwave Precipitation Radiometer (AMPR) aboard the NASA ER-2 during the Tropical Ocean and Global Atmosphere Coupled Ocean-Atmosphere Response Experiment. The AMPR measures linearly polarized radiation at 10.7, 19.35, 37.1, and 85.5 GHZ. Nadir brightness temperature scatterplots suggest that the three lower frequencies respond primarily to emission/absorption processes. Strong ice scattering is relatively rare, as absolute magnitudes of the ice-scattering signature do not approach those measured in strong convection over land. This is apparently related to the reported weaker updraft velocities over tropical oceans, which would create and suspend relatively smaller graupel or hail particles in the upper cloud. Observations withi.
Fluidic adaptive lens of transformable lens type

Fluidic adaptive lenses with a transformable lens type were demonstrated. By adjusting the fluidic pressure, not only can the lens properties, such as the focal distance and numerical aperture, be tuned dynamically but also different lens types, such as planoconvex, planoconcave, biconvex, biconcave, positive meniscus, and negative meniscus lenses, can be formed. The shortest focal length for a 20 mm aperture adaptive lens is 14.3 mm when the device is transformed into a positive lens, and −6.3 mm when transformed into a negative lens. The maximum resolution of the fluidic lens is better than 40 line pairs/mm.
Phase fluctuations in a squeezed state using measured phase operators

The phase fluctuations in a squeezed state are considered by using the recently introduced measured phase operators of Barnett and Pegg [ J. Phys. A19, 3849 ( 1986)], which permit considerably simplified calculations compared with conventional (e.g., Susskind–Glogower) operators and yet nonetheless are found to give agreement with physical expectations for a squeezed state, while more or less producing agreement with known results in various limits.
A Monotonic Algorithm for Eigenvalue Optimization in Shape Design Problems of Multi-Density Inhomogeneous Materials

Many problems in engineering shape design involve eigenvalue optimizations. The relevant difficulty is that the eigenvalues are not continuously differentiable with respect to the density. In this paper, we are interested in the case of multi-density inhomogeneous materials which minimizes the least eigenvalue. With the finite element discretization, we propose a monotonically decreasing algorithm to solve the minimization problem. Some numerical examples are provided to illustrate the efficiency of the present algorithm as well as to demonstrate its availability for the case of more than two densities. As the computations are sensitive to the choice of the discretization mesh sizes, we adopt the refined mesh strategy, whose mesh grids are 25-times of the amount used in [S. Osher and F. Santosa, J. Comput. Phys., 171 (2001), pp. 272-288]. We also show the significant reduction in computational cost with the fast convergence of this algorithm. AMS subject classifications: 35P15, 65K10, 74S05
Velocity fields in late-type galaxies from H-alpha Fabry-Perot interferometry. IV - Kinematics and dynamics of the SAB(s) spiral NGC 5236 (M83)

Le champ des vitesses dans la spirale barree faible NGC 5236, (M T o (B)=−20,00), situee a Δ=3,7 Mpc dans le groupe du Centaure, est obtenu a partir de 2770 vitesses mesurees sur 16 interferogrammes Hα. On donne egalement une carte de l'emission Hα et un catalogue de 60 regions H II brillantes. On analyse le champ des vitesses au centre (r=3,6'=3,8 kpc). Les masses obtenues en comparant la courbe de rotation moyenne a divers modeles, conventionnels, axisymetriques de distribution de la masse (en negligeant la dispersion des vitesses) sont dans le domaine 5,8≤M T ≤14,6×10 10 M ○. Le modele de Toomre generalise, a deux composantes, comportant un bulbe «chaud» est en meilleur accord avec la photometrie
Two New Low Galactic D/H Measurements from the Far Ultraviolet Spectroscopic Explorer

We analyze interstellar absorption observed toward two subdwarf O stars, JL 9 and LS 1274, using spectra taken by the Far Ultraviolet Spectroscopic Explorer (FUSE). Column densities are measured for many atomic and molecular species (H I, D I, C I, N I, O I, P II, Ar I, Fe II, and H2), but our main focus is on measuring the D/H ratios for these extended lines of sight, as D/H is an important diagnostic for both cosmology and Galactic chemical evolution. We find D/H = (1.00 ± 0.37) × 10-5 toward JL 9 and D/H = (0.76 ± 0.36) × 10-5 toward LS 1274 (2 σ uncertainties). With distances of 590 ± 160 and 580 ± 100 pc, respectively, these two lines of sight are currently among the longest Galactic lines of sight with measured D/H. With the addition of these measurements, we see a significant tendency for longer Galactic lines of sight to yield low D/H values, consistent with previous inferences about the deuterium abundance from D/O and D/N measurements. Short lines of sight with H I column densities of log N(H ) < 19.2 suggest that the gas-phase D/H value within the Local Bubble is (D/H)LBg = (1.56 ± 0.04) × 10-5. However, the four longest Galactic lines of sight with measured D/H, which have d > 500 pc and log N(H ) > 20.5, suggest a significantly lower value for the true local disk gas-phase D/H value, (D/H)LDg = (0.85 ± 0.09) × 10-5. One interpretation of these results is that D is preferentially depleted onto dust grains relative to H and that longer lines of sight that extend beyond the Local Bubble sample more depleted material. In this scenario, the higher Local Bubble D/H ratio is actually a better estimate than (D/H)LDg for the true local disk D/H, (D/H)LD. However, if (D/H)LDg is different from (D/H)LBg simply because of variable astration and incomplete interstellar medium mixing, then (D/H)LD = (D/H)LDg.
Modelling and numerical approach to a class of metal‐forming problems—Quasi‐steady case

A class of quasi‐steady metal‐forming problems, with rigid‐plastic, incompressible, strain and strain‐rate dependent material model and with unilateral frictionless and nonlinear, nonlocal Coulomb's frictional contact conditions is considered. A coupled variational formulation, constituted of a variational inequality, with nonlinear and nondifferentiable terms, and a strain evolution equation, is derived and under a restriction on the material characteristics and using a variable stiffness parameters method with time retardation, existence, uniqueness and convergence results are obtained and presented. An algorithm, combining this method and the finite element method, is proposed and applied for solving an example strip drawing problem. Copyright © 2011 John Wiley & Sons, Ltd.
I-O map inversion, zero dynamics and flight control

The trajectory control of aircraft in rapid, nonlinear maneuvers is discussed. Based on nonlinear invertibility theory, a control law is derived to independently control roll, pitch, and sideslip angles using rudder, elevator, and aileron. Integral feedback is introduced in order to obtain robustness in the control system to parameter uncertainty. The stability of the zero dynamics is examined. Simulation results are presented to show that in a closed-loop system, precise simultaneous lateral and longitudinal maneuvers can be performed despite the presence of uncertainty in the stability derivatives. >
Implications of Stochastic and Deterministic Filters as Ensemble-Based Data Assimilation Methods in Varying Regimes of Error Growth

Accurate numerical prediction of fluid flows requires accurate initial conditions. Monte Carlo methods have become a popular and realizable approach to estimating the initial conditions necessary for forecasting, and have generally been divided into two classes: stochastic filters and deterministic filters. Both filters strive to achieve the error statistics predicted by optimal linear estimation, but accomplish their goal in different fashions, the former by way of random number realizations and the latter via explicit mathematical transformations. Inspection of the update process of each filter in a one-dimensional example and in a two-dimensional dynamical system offers a geometric interpretation of how their behavior changes as nonlinearity becomes appreciable. This interpretation is linked to three ensemble assessment diagnostics: rms analysis error, ensemble rank histograms, and measures of ensemble skewness and kurtosis. Similar expressions of these diagnostics exist in a hierarchy of models. The geometric interpretation and the ensemble diagnostics suggest that both filters perform as expected in a linear regime, but that stochastic filters can better withstand regimes with nonlinear error growth. Accurate numerical prediction of fluid flows requires accurate initial conditions. In an effort to approximate optimal estimation methods for linear problems with Gaussian error statistics, Monte Carlo methods have become a popular and realizable approach to estimating the initial conditions necessary for forecasting (e.g., Evensen and van Leeuwen 1996; Houtekamer and Mitchell 2001). Ensemble methods based on linear theory have taken two general forms: stochastic filters and deterministic filters. Both filters strive for the same result, namely to achieve the error statistics predicted by optimal linear estimation, but accomplish their goal in different fashions, the former by way of random number realizations and the latter via explicit mathematical transformations. We seek to understand the implications of these different methodologies when applied to different regimes of error growth. Through geometric considerations in a one-dimensional example and in a two-dimensional system’s state space, we formulate an interpretation of the update process for both filter types. We examine how this interpretation expresses itself in three ensemble diagnostics, root-mean-square (rms) analysis error, ensemble rank histograms, and measures of ensemble skewness and kurtosis. We then monitor filter behavior with these di
Video systems for PIV recording

CCD video cameras have been used extensively in recent years for image capture in fluid flow measurements with the particle image velocimetry (PIV) technique. Recent advances in CCD imaging technology have improved and extended the PIV technique to new applications, ranging from rotating machinery to 3D measurements. The progressive scan interline transfer CCD allows the time interval between two consecutive frames to be very small. Combined with frame straddling technique and the cross correlation analysis method, video cameras with such CCD design can be used for high-speed flow measurements, without the need for image shifting or image tagging methods to resolve directional ambiguity. Investigation of the pixel fill factor in CCD designs has indicated that the particle image diameter of two pixels or more is required to minimize the error in particle image location, which is important for accurate PIV measurements. Results of the investigation on a commercial video camera with the progressive scan interline transfer CCD design for its capability in high-speed flow measurements are presented. It is shown that this camera can achieve images for a time interval as small as s and for velocities of up to 250 m in the experiment.
Nonparametric estimation in semi-parametric univariate mixture models

We introduce new estimates of the mixing proportions, locations, and variances of the components of a finite univariate mixture model. We assume that the components are symmetric and differ only in the locations. No parametric model assumptions are imposed on the components. Further, when there is additional information available in the form of training samples that contain information concerning the mixing proportion, the new methods are robust to the symmetry assumption.
Distributions for residual autocovariances in parsimonious periodic vector autoregressive models with applications

The asymptotic distribution of the residual autocovariance matrices in the class of periodic vector autoregressive time series models with structured parameterization is derived. Diagnostic checking with portmanteau test statistics represents a useful application of the result. Under the assumption that the periodic white noise process of the periodic vector autoregressive time series model is composed of independent random variables, we demonstrate that the finite sample distributions of the Hosking‐Li‐McLeod portmanteau test statistics can be approximated by those of weighted sums of independent chi‐square random variables. The quantiles of the asymptotic distribution can be computed using the Imhof algorithm or other exact methods. Thus, using the (single) chi‐square distribution for these test statistics appears inadequate in general, although it is often recommended in practice for diagnostic methods of that kind. A simulation study provides empirical evidence.
Attention to primes is insufficient for stereotype priming

The current study investigated category-based activation of stereotypes when processing of the category primes is mandatory. In three high-powered pre-registered experiments (total n=211), we compared responses to age-stereotypic traits (e.g., lonely) after presenting matching versus mismatching category primes (old vs. young faces) of which the age information had to be remembered. Experiments varied in stimulus-onset-asynchronies (SOA; 250ms vs. 500ms), and in the inclusion of neutral conditions of prime and target factors. Consistently across all experiments, no facilitation of matching category primes was observed, indicating that category information alone does not facilitate processing of matching stereotypes even if it is attended. The theoretical and practical implications for activation and representation of stereotypes are discussed.
Optimal convolution filters and an algorithm for the detection of wide linear features

The author presents the theory for developing optimal convolution filters for the identification of wide linear features and an algorithm for distinguishing them from other types of image feature. Some filters are given and the results of applying the algorithm to some real images are shown. These filters, and the algorithm, are appropriate for use in knowledge based systems which aim at identifying roads, canals, hedges and rivers in images, or in digitised maps.