Miracle-dz/UniFAR-FTUs huggingface dataset:
Influence of frequency and bias voltage on dielectric properties and electrical conductivity of Al/TiO2/p-Si/p+ (MOS) structures

In this study, the frequency and voltage dependence of the dielectric constant (ε′), dielectric loss (ε″), loss tangent (tan δ), electric modulus (M′ and M″) and ac electrical conductivity (σac) of Al/TiO2/p-Si (MOS) structures has been investigated using the capacitance–voltage (C–V) and conductance–voltage (G/ω–V) characteristics. A TiO2 thin film was deposited on the p-type Si substrate by using the sol–gel dip coating method. These C–V and G/ω–V characteristics were measured by applying a small ac signal of 50 mV amplitude in the frequency range 5 kHz–1 MHz, while the dc bias voltage was swept from (−4 V) to (4 V) at room temperature. Experimental results show that ε′, ε″, tan δ and σac are strongly frequency and voltage dependent. Accordingly, it has been found that as the frequency increases, ε′ and ε″ values decrease while an increase is observed in σac and the electric modulus. The results can be concluded to imply that the interfacial polarization can more easily occur at low frequencies consequently contributing to the deviation of dielectric properties and ac electrical conductivity of Al/TiO2/p-Si/p+ (MOS) structures.
INFINITE STREAM OF HELE-SHAW BUBBLES

Exact solutions are presented for a steady stream of bubbles in a Hele–Shaw cell when the effect of surface tension is neglected. These solutions form a three‐parameter family. For specified area and distance between bubbles, the speed of the bubble remains arbitrary when surface tension is neglected. However, numerical and analytical evidence indicates that this arbitrariness is removed by the effect of surface tension. The branch of solutions that corresponds to the McLean–Saffman finger solution were primarily studied. A dramatic increase was observed in bubble speeds when the distance between bubbles is on the order of a bubble diameter, which may have relevance to experiments done by Maxworthy [J. Fluid Mech. 173, 95 (1986)].
A Tube-MPC Approach to Autonomous Multi-Vehicle Racing on High-Speed Ovals

Autonomous vehicle racing has emerged as vibrant, innovative technology development, demonstration platform in recent years. Universities, companies demonstrate their achievements on various vehicles - from 1:10th to full-scale prototypes. One of those platforms is the Dallara AV-21, and the spec-vehicle for the Indy Autonomous Challenge. This paper outlines the robust model predictive control (MPC) concept used within the software stack of the TUM Autonomous Motorsport team. It is based on a simplified friction-limited point mass model and a set of low-level feedback controllers. The remaining model uncertainties are managed via introducing a constraint-tightening approach based on a Tube-MPC approach. In contrast to classical tracking controllers, the optimization problem is formulated to freely optimize the trajectory while staying within certain maximum deviations of the reference. This approach allows to rely on a coarse output of the trajectory planning approach while maintaining smoothness requirements in steering, throttle, and brake actuation. The paper highlights the advantages of the proposed robust reoptimization concept compared to pure tracking formulations. It showcases the performance compared to a classical LQR controller and an MPC, which utilizes a vehicle model with a more sophisticated tire model. The controller achieved a top speed of <inline-formula><tex-math notation="LaTeX">$\text{265 kmh}^{-1}$</tex-math></inline-formula> and lateral accelerations up to <inline-formula><tex-math notation="LaTeX">${\text{21 ms}}^{-2}$</tex-math></inline-formula> during a two-vehicle competition involving dynamic overtaking maneuvers on the Las Vegas Motor Speedway, a famous racetrack with turns banked up to <inline-formula><tex-math notation="LaTeX">$20^{\circ }$</tex-math></inline-formula>.
The Threat of Distributed Denial-of-Service Attack for User Equipment in 5G Networks

In an existing study by Positive Technologies, researchers simulated a Distributed Denial of Service (DDoS) attack on User Equipment (UE). The goal was to test the impact of a Distributed Denial of Service attack by studying the Diameter signaling protocol, which coordinates data among different IP network elements. The result revealed that 5G networks were vulnerable to DDoS attacks and a successful attack on UE can cause devastating damage. Therefore, mobile security must be a top priority for all operators. 5G is intended to cover a wide range of needs and use cases, enhancing the user’s perspective. 5G will also be able to deliver excellent security by considering authentication and access control systems. In modeling 5G authentication and access control, it is critical to consider both legacy AKA’s flaws and 5G’s new expectations. In this study, we examine the 3GPP’s current 5G architectural solutions.
Ultraviolet Spectral Variability and the Lyα Forest in the Lensed Quasar Q0957+561

Far-ultraviolet spectra of the gravitational lens components Q0957+561A, B were obtained with the Hubble Space Telescope Faint Object Spectrograph (FOS) at five equally spaced epochs, one every 2 weeks. We confirm the flux variability of the quasar's Lyα and O VI λ1037 emission lines in IUE spectra reported in earlier work of Dolan et al. The fluxes in these lines vary on a timescale of weeks in the observer's rest frame, independently of each other and of the surrounding continuum. The individual spectra of each image were co-added to investigate the properties of the Lyα forest along the two lines of sight to the quasar. Absorption lines having equivalent width Wλ ≥ 0.3 Å in the observer's frame not previously identified by Michalitsianos et al. as interstellar lines, metal lines, or higher order Lyman lines were taken to be Lyα forest lines. The existence of each line in this consistently selected set was then verified by its presence in two archival FOS spectra with ~ 1.5 times higher signal to noise than our co-added spectra. Lyα forest lines with Wλ ≥ 0.3 Å appear at 41 distinct wavelengths in the spectra of the two images. One absorption line in the spectrum of image A has no counterpart in the spectrum of image B, and one line in image B has no counterpart in image A. Based on the separation of the lines of sight over the redshift range searched for Lyα forest lines, the density of the absorbing clouds in the direction of Q0957+561 must change significantly over a distance R = 160 h kpc in the simplified model where the absorbers are treated as spherical clouds and the characteristic dimension, R, is the radius. (We adopt H0 = 50 h50 km s-1 Mpc-1, q0 = , and Λ = 0 throughout this paper.) The 95% confidence interval on R extends from 50 to 950 h kpc. We show in the Appendix that the fraction of Lyα forest lines that appear in only one spectrum can be expressed as a rapidly converging power series in 1/r, where r the ratio of the radius of the cloud to the separation of the two lines of sight at the redshift of the cloud. This power series can be rewritten to give r in terms of the fraction of Lyα forest wavelengths that appear in the spectrum of only one image. A simple linear approximation to the solution that everywhere agrees with the power series solution to better than 0.8% for r ≥ 2 is derived in the Appendix.
Model Selection for Nested and Overlapping Nonlinear, Dynamic and Possibly Mis-Specified Models

The literature on model comparison often requires the assumption that the true conditional distribution corresponds to that of one of the competing models. This strong assumption has been extended by the notion of encompassing and in likelihood based model comparisons. This paper takes the latter approach and develops tests for the comparison of competing nonlinear dynamic models, focusing on the nested and overlaping cases. The null hypothesis is that the models are equally close to the data generating process (DGP), according to a certain measure of closeness. The alternative is that one model is closer to the DGP. The models can be correctly specified or not. Their parameters can be estimated by a variety of methods, including (pseudo) maximum likelihood and ordinary least squares. The tests are symmetric and directional. Their asymptotic distribution under the null is either normal or a weighted sum of chi-squared distributions, depending on the nesting characteristics of the competing models. The comparison of nested AR models, and of nested ARMA models with GARCH errors and exogenous forcing variables (ARMAX-GARCH) are discussed as examples.
Intelligent Reflecting Vehicle Surface: A Novel IRS Paradigm for Moving Vehicular Networks

Intelligent reflecting surface (IRS) has recently received much attention from the research community due to its potential to achieve high spectral and power efficiency cost-effectively. In addition to traditional cellular networks, the use of IRS in vehicular networks is also considered. Prior works on IRS-aided vehicle-to-everything communications focus on deploying reflection surfaces on the facades of buildings along the road for sidelink performance enhancement. This paper goes beyond the state of the art by presenting a novel paradigm coined Intelligent Reflecting Vehicle Surface (IRVS). It embeds a massive number of reflection elements on vehicles' surfaces to aid moving vehicular networks in military and emergency communications. We propose an alternative optimization method to optimize jointly active beamforming at the base station and passive reflection across multiple randomly-distributed vehicle surfaces. Performance evaluation in terms of sum spectral efficiency under continuous, discrete, and random phase shifts is conducted. Numerical results reveal that IRVS can substantially improve the capacity of a moving vehicular network.
Global solutions of the Cauchy problem for the (classical) coupled Maxwell-Dirac and other nonlinear Dirac equations in one space dimension

The existence of global solutions is proved for the Maxwell-Dirac equations, for the Thirring model (Dirac equation with vector self-interaction), for the Klein-Gordon-Dirac equations and for two Dirac equations coupled through a vector-vector interaction (Federbusch model) in one space dimension. The proof is based on charge conservation, and depends on an "a priori" estimate of 11 llo for the Dirac field. This estimate is obtained only on the basis of algebraical properties of the nonlinear term, and allows us to simplify the proofs of global existence. We obtain it by computing aoj' + al j? , with aoj? + al jI = 0 being the continuity equation which expresses charge conservation. We also prove global existence for the Thirring and Federbusch models coupled in standard form with the electromagnetic field.
The inner radio structure of Centaurus A - Clues to the origin of the jet X-ray emission

VLA observations at 1.4 and 4.9 GHz of the jet and inner lobes of the nearby radio galaxy Centaurus A have been used to construct maps of total intensity and polarization at resolutions of 31 x 10 and 3.6 x 1.1 arcsec. Surface brightness and pressure distributions in the jet, combined with the apparent X-ray emission from the ISM of NGC 5128, indicate that it is thermally confined. A comparison of the radio structure and the optical galaxy shows that the jet in Cen A emerges nearly along the major axis of the elliptical stellar component that is parallel to the angular momentum vector of the dust lane. The outer radio structure bends toward the galaxy minor axis. Evidence is found for a common synchrotron radiation origin of the full spectrum jet emission.
Acoustic distortion products from the ear of a grasshopper

Distortion-product otoacoustic emissions were recorded from the tympanum of the grasshopper, Locusta migratoria. The hearing organ of this insect is in direct contact with the tympanum and does not contain sensory hair cells. 2f1−f2 distortions were measured for stimulus frequencies between 2–70 kHz. For frequencies between 3–9 kHz, the level of 2f1–f2 was 30–50 dB below the stimulus level. 2f1−f2 threshold curves calculated from distortion growth functions at different f2 frequencies are most sensitive between 3–9 kHz. These thresholds match the auditory sensitivity of low frequency receptor neurons in the ear [Romer, J. Comp. Physiol. 109, 101–122 (1976)]. In contrast to vertebrates, the dependence of the 2f1−f2 level on the frequency ratio f2/f1 did not show distinct maxima for most f2 frequencies. The distortion levels were largest for small ratios close to 1. The behavior of 2f1−f2 was significantly different for stimulus frequencies below and above 10 kHz. Below 10 kHz, the thresholds were more sens.
On asymptotics of Jacobi polynomials

The asymptotic behavior of Jacobi polynomials $P_n^{\alpha + an,\beta + bn} (x)$ and Laguerre polynomials $L_n^{\alpha + an} (b + nx)$ is found when $n \to \infty $ and a, b, $\alpha $, $beta$ are real constants, $a > - 1$, $b > - 1$, and x is a real variable.
On certain subclasses of analytic functions involving a linear operator

A certain general classS(a;c;A;B) of analytic functions involving a linear operator is introduced. The objective is to investigate various properties and characteris- tics of this class. Several applications of the results (obtained here) to a class of fractional calculus operators are also considered. The results contain some of the earlier work in univalent function theory.
On Mechanism of Electron Scattering in InP

The Hall mobility of electrons was studied in n-InP single crystals in the temperature range from 77 to 1000°K at electron concentrations n = 2 × 1015 to 2 × 1017 cm−3 and mobilities μ = 3 × 103 to 4.3 × 104 cm2/Vs. The results agree well with calculations for the mixed mechanism of electron scattering on optical phonons, μ0 = (100/√T)(exp(500/T) −1), and acoustic phonons, μa = 6.53 × 107T−3/2 cm2/Vs (the deformation potential is assumed to be equal to 21 eV). Scattering on ions and neutral impurity atoms is important in specimens with n > 5 × 1015 cm−3 at low temperatures. The concentration of neutral impurity atoms does not exceed 1014 cm−3 in pure specimens, while in specimens with n > 1016 cm−3NN reaches the value of 1016 cm−3 and more. The results of the Hall coefficient dependence on the magnetic field strength (0.3 to 20 kOe) at 77 and 300 °K show that the Hall factor A (R = A/nec) approximates 1 in all the specimens with the exception of pure specimens where A ≈ 1.13 at 77 °K. These results agree well with the conclusions drawn from the analysis of temperature and concentration dependences of mobility. Im Temperaturbereich zwischen 77 und 1000 °K wurde an n-leitenden InP-Einkristallen mit Elektronenkonzentrationen von n = 2 × 1015 bis 2 × 1017 cm−3 und Beweglichkeiten von μ = 3 × 103 bis 4,3 × 104 cm2/Vs die Hallbeweglichkeit untersucht. Die Ergebnisse stimmen gut mit Rechnungen fur einen gemischten Streumechanismus der Elektronen an optischen Phononen, μ0 = (100/√T)(exp(500/T) −1), und akustischen Phononen, μa = = 6,53 × 107T−3/2 cm2/Vs, uberein (das Deformationspotential wird zu 21 eV angenommen). Streuung an Ionen und neutralen Defekten ist in Proben mit n > 5 × 1015 cm−3 bei niedrigen Temperaturen wesentlich. Die Konzentration von neutralen Defekten ubersteigt in reinen Proben nicht 1014 cm−3, wahrend in Proben mit n > 1016 cm−3NN den Wert von 1016 cm−3 und mehr erreicht. Die Ergebnisse der Abhangigkeit des Hallkoeffizienten vom Magnetfeld (0,3 bis 20 kOe) bei 77 und 300 °K zeigen, das der Hallfaktor A (R = A/nec) in allen Proben naherungsweise 1 ist, mit Ausnahme reiner Proben, wo A ≈ 1,13 bei 77 °K wird. Diese Ergebnisse stimmen gut mit Schlusfolgerungen uberein, die aus der Analyse der Temperatur- und Konzentrationsabhangigkeit der Beweglichkeit gezogen wurden.
Low frequency electromagnetic radiation 10–900 cycles per second

During the period of July 10 to September 15, 1955, detection of electromagnetic signals in the frequency range 10 to 900 cycles per second was undertaken. Loops and a vertical antenna were used in a site remote from man-made interference. The spectrum was analyzed with a narrow bandwidth (2 to 6 cycles per second) amplifier. Indicated diurnal patterns show a maximum around local midnight. The peak in the band lies in the region 40 to 200 cycles per second. During one period of several hours, a large increase in narrow band energy was seen near 33 cycles per second. The possibilities of this being radiation at the gyrofrequency of the sodium ion is discussed.
Geometry reduction in room acoustics modeling

The complexity of a room model affects to the computational resources required to model its acoustics by means of geometrical acoustics modeling methods. Thus, a method for reducing the geometry of the room models is presented for static room geometries. The topology of the model is simplified in a process where the model is first decomposed into a volumetric structure. The surface is reconstructed by utilizing this structure, and subsequently simplified by merging coplanar regions. The results of the method are verified by extracting room acoustical attributes from the original and reduced models with the ODEON room acoustics prediction software. It is shown that the most important acoustic properties have been preserved, even with relatively high reduction rates.
Mechanism and scaling for convection of isolated structures in nonuniformly magnetized plasmas

Large-scale radial advection of isolated structures in nonuniformly magnetized plasmas is investigated. The underlying mechanism considered is due to the nonlinear evolution of interchange motions, without any presumption of plasma sheaths. Theoretical arguments supported by numerical simulations reveal an inertial scaling for the radial velocity of isolated structures in the ideal limit. This velocity increases as the square root of the structure size relative to the length scale of the magnetic field. The magnitude of the radial advection velocity, as well as the dynamical evolution of the structures, compares favorably with recent experimental measurements of radially propagating blob structures in the scrape-off layer of magnetically confined plasmas.
Forces on Moving Magnets due to Eddy Currents

A magnet or a current‐carrying coil, moving with constant velocity above a conducting plate, will experience magnetic lift and drag forces from the eddy currents induced in the plate. The lift and drag forces are calculated for various coil geometries on the assumption that the conducting plate is thin. For this model, the lift at high speeds approaches the force between the coil and its ``image'' located directly below it, and the drag force falls off as (velocity)−1. The ratio of lift to drag is found to be independent of coil geometry, but the velocity dependence of the lift is greatly affected by the geometry. The ratio of lift to coil weight can be as high as 2000 for a superconducting coil moving at 300 mph at 0.1 m above a conducting plate. The relevance of the calculation to magnetically supported high‐speed vehicles is discussed.
On the Alternate Transmission Mode for Polarimetric Phased Array Weather Radar

AbstractPulse-to-pulse switching of polarizations (alternate transmission mode) is considered for polarimetric phased array radar (PAR). It is argued that the performance of the radar in terms of data quality should match or exceed the achieved standards of the Weather Surveillance Radar-1988 Doppler (WSR-88D). It turns out that the most stringent demand on the radar concerns the surveillance scan at the lowest elevations wherein the polarimetric variables are free of overlaid echoes, while ground clutter is significantly reduced. The scan uses a long pulse repetition time that has repercussion on the standard errors of the polarimetric variables and hence the choice of polarimetric mode. Herein the dwell time of this scan serves as a benchmark for comparisons of the accuracy of estimates. Because weather PAR should provide useful information at low signal-to-noise ratios (SNR) as low as those measured by the WSR-88D, the statistics of polarimetric variables, known at high SNR, is extended to low SNRs. It.
Global changes of the band structure and the crystal lattice of Ga(N, As) due to hydrogenation

The effect of hydrogenation on five GaN x As 1 - x epitaxial layers (0.00043≤x≤0.019) grown by metal-organic vapor-phase epitaxy was investigated. Photomodulated reflectance (PR) and photoluminescence spectroscopy were used to study the electronic band structure, and x-ray diffraction (XRD) and Raman spectroscopy to probe, respectively, the static and dynamic properties of crystal lattice before and after hydrogenation. Hydrogen almost completely neutralizes the effect of N on the band structure of the GaAs host. The direct band gap E - and the spin-orbit split-off band E_ + Δ 0 blueshift toward the corresponding energies in GaAs and the E + band disappears after hydrogenation. The PR spectra of hydrogenated GaN x As 1 - x resemble broad GaAs-like spectra. The XRD traces reveal that hydrogenation removes the tensile strain in GaN x As 1 - x layers and even induces compressive strain. After hydrogenation the GaAs-like features in the Raman spectra persist whereas the local vibrational mode due to N disappears. Three H-related modes can be distinguished in the Raman spectra.
An experimental investigation of the stability of plane Poiseuille flow

Stability experiments were made on plane Poiseuille flow generated in a long channel of a rectangular cross-section with a width-to-depth ratio of 27·4. By reducing the background turbulence down to a level of 0·05 %, we succeeded in maintaining the flow laminar at Reynolds numbers up to 8000, which is much larger than the critical Reynolds number of the linear theory, about 6000. The downstream development of the sinusoidal disturbance introduced by the vibrating ribbon technique was studied in detail at various frequencies in the range of Reynolds number from 3000 to 7500. This paper presents the experimental results and clarifies the linear stability, the nonlinear subcritical instability and the breakdown leading to the transition.
Full-Wave Analysis of the Optimum Triplicator

Starting from the results obtained in the scalar domain for the diffractive optical element that produces three equi-intense diffraction orders with the maximum efficiency, we present a full-wave electromagnetic treatment of such optimum triplicator. The performances of this element are studied in the resonance domain and in the scalar limit as far as the dependence on the grating period, the incidence angle, and the wavelength of the impinging radiation is concerned. Furthermore, the effects of a quantization of the phase profile to a discrete number of phase levels are studied.