Miracle-dz/UniFAR-FTUs huggingface dataset:
Active Cross Pre-Compensation Decoupling Control of X-Y Linear Motor Platform Based on Contour Error Analysis Model

To improve the position accuracy of the X-Y linear motor motion platform, this paper derives a contour error analysis model (CEAM) and proposes an active cross pre-compensation decoupling controller (ACPDC). Three major factors affect the tracking performance of the X-Y motion platform are obtained from the derived CEAM: uniaxial-axis subsystem performance, dynamic compatibility between multiple axes, and disturbances. CEAM also shows that better contour control can be achieved by combining the unified modeling idea. Therefore, the ACPDC proposed in this paper integrates the inter-axis controller and single-axis subsystem by establishing a unified control law that combines active pre-compensation control with linear active disturbance rejection control. The theoretical analysis based on CEAM shows that ACPDC achieves improvements in the above three aspects. Finally, experimental results on an X-Y linear motor platform support the CEAM analysis that ACPDC has better contouring performance than other multi-axis controllers. Compared with these controllers, ACPDC has the best system robustness and uniaxial tracking performance.
The evolution of galaxy sizes

Abstract We present a study of galaxy sizes in the local Universe as a function of galaxy environment, comparing clusters and the general field. Galaxies with radii and masses comparable to high-z massive and compact galaxies represent 4.4% of all galaxies more massive than 3 × 1010M⊙ in the field. Such galaxies are 3 times more frequent in clusters than in the field. Most of them are early-type galaxies with intermediate to old stellar populations. There is a trend of smaller radii for older luminosity-weighted ages at fixed galaxy mass. We show the relation between size and luminosity-weighted age for galaxies of different stellar masses and in different environments. We compare with high-z data to quantify the evolution of galaxy sizes. We find that, once the progenitor bias due to the relation between galaxy size and stellar age is removed, the average amount of size evolution of individual galaxies between high- and low-z is mild, of the order of a factor 1.6.
CoRoT target HD 51844: a δ Scuti star in a binary system with periastron brightening†

Abstract The star HD 51844 was observed in the CoRoT LRa02 as a target in the seismology field, which turned out to be an SB2 system. The 117-day light curve revealed δ Scuti pulsations in the range of 6 to 15 d−1 where four frequencies have amplitudes larger than 1.4 mmag, and a rich frequency spectrum with amplitudes lower than 0.6 mmag. Additionally, the light curve exhibits a 3-mmag brightening event recurring every 33.5 days with a duration of about 5 days. The radial velocities from spectroscopy confirmed that the star is an eccentric binary system with nearly identical masses and physical parameters. The brightening event in the light curve coincides with the maximum radial-velocity separation showing that the brightening is in fact caused by tidal distortion and/or reflected light. One component displays large line-profile variations, while the other does not show significant variation. The frequency analysis revealed a quintuplet structure of the four highest-amplitude frequencies, which is due to the orbital motion of the pulsating star.
The changing GMC population in galaxy interactions

With the advent of modern observational efforts providing extensive giant molecular cloud catalogues, understanding the evolution of such clouds in a galactic context is of prime importance. While numerous previous numerical and theoretical works have focused on the cloud properties in isolated discs, few have looked into the cloud population in an interacting disc system. We present results of the first study investigating the evolution of the cloud population in galaxy experiencing an M51-like tidal fly-by using numerical simulations including star formation, interstellar medium cooling and stellar feedback. We see the cloud population shift to large unbound clouds in the wake of the companion passage, with the largest clouds appearing as fleeting short-lived agglomerations of smaller clouds within the tidal spiral arms, brought together by large scale streaming motions. These are then sheared apart as they leave the protection of the spiral arms. Clouds appear to lead diverse lives, even within similar environments, with some being born from gas shocked by filaments streaming into the spiral arms, and others from effectively isolated smaller colliding pairs. Overall this cloud population produces a shallower mass function than the disc in isolation, especially in the arms compared to the inter-arm regions. Direct comparisons to M51 observations show similarities between cloud populations, though models tailored to the mass and orbital models of M51 appear necessary to precisely reproduce the cloud population.
Unbalanced Pomeransky-Sen’kov black ring

The Pomeransky-Sen'kov solution is well known to describe an asymptotically flat doubly rotating black ring in five dimensions, whose self-gravity is exactly balanced by the centrifugal force arising from the rotation in the ring direction. In this paper, we generalize this solution to the unbalanced case, in which there is in general a conical singularity in the space-time. Unlike a previous form of this solution presented in the literature, our form is much more compact. We describe in detail how this solution can be derived using the inverse-scattering method, and study its various properties. In particular, we show how various known limits can be recovered as special cases of this solution.
Sol–Gel Routes toward Ceramic Nanofibers for High-Performance Thermal Management

Ceramic-based nanofiber materials for high-performance thermal management have drawn increasing attention owing to their high-temperature resistance, efficient thermal insulation, superior mechanical flexibility, as well as excellent physical–chemical stability. We present an overview of the ceramic-based nanofiber obtained by sol–gel routes for high-performance thermal management, including the materials, the fabrication methods of the sol–gel route, and their application for thermal management. We first provide a brief introduction to the ceramic-based nanofibers. The materials and fabrication methods of the sol–gel route are further discussed in the second part, including the kinds of nanofibers such as oxide, carbide, and nitride, and the methods such as centrifugal spinning, electrospinning, solution blow spinning, and self-assembly. Finally, their application for thermal management is further illustrated. This review will provide some necessary suggestions to researchers for the investigation of ceramic-based nanofibers produced with the sol–gel route for thermal management.
Effects of pulse collisions in a multilayer system with noninstantaneous cubic nonlinearity

Numerical simulations of an ultrashort pulse propagation in a one-dimensional nonlinear photonic crystal are carried out. It is known that the relaxation of cubic nonlinearity is the reason for the effect of pulse self-trapping in such a multilayer system. In this paper we study further implications of this effect. It is shown that the trapped light absorbs additional low-intensity pulses which cannot be self-trapped per se. On the other hand, such low-intensity pulses are subject to the so-called induced trapping when light becomes trapped due to a collision of two such pulses. We consider the conditions for this effect in cases of both co- and counter-propagating pulses.
Sexual imprinting leads to speciation in locally adapted populations

Abstract Sexual imprinting is widespread in birds and other species but its existence requires explanation. Our results suggest that sexual imprinting leads to speciation in locally‐adapted populations if a neutral mating cue—e.g., novel plumage coloration—arises through mutation. Importantly, the mating cue locus is not linked to adaptation loci. Local adaptation is a necessary precursor to speciation and occurs when evolution results in stable genetic polymorphisms with one allele predominating in some areas while others predominate elsewhere. Here we use a deterministic two‐niche population genetic model to map the set of migration and selection rates for which polymorphic evolutionary outcomes, i.e., local adaptations, can occur. Approximate equations for the boundaries of the set of polymorphic evolutionary outcomes were derived by Bulmer (American Naturalist, 106, 254, 1972), but our results, obtained by deterministic simulation of the evolutionary process, show that one of Bulmer's equations is inaccurate except when the level of dominance is 0.5, and fails if one of the alleles is dominant. Having an accurate map of the set of migration and selection rates for which polymorphic evolutionary outcomes can occur, we then show using the model of Sibly et al. (Ecology and Evolution, 9, 13506, 2019) that local adaptation in all analyzed cases leads to speciation if a new neutral mating cue arises by mutation. We finish by considering how genome sequencing makes possible testing our model and its predictions.
Probing the primordial universe with gravitational waves detectors

The spectrum of primordial gravitational waves (GWs), especially its tilt nT, carries significant information about the primordial universe. Combining recent aLIGO and Planck2015+BK14 data, we find that the current limit is nT=0.016+0.614−0.989 at 95% C.L. We also estimate the impacts of Einstein Telescope and LISA on constraining nT. Moreover, based on the effective field theory of cosmological perturbations, we make an attempt to confront some models of early universe scenarios, which produce blue-tilted GWs spectrum (nT>0), with the corresponding datasets.
High-Rate Plastic Deformation of Nanocrystalline Tantalum to Large Strains: Molecular Dynamics Simulation

Recent advances in the ability to generate extremes of pressure and temperature in dynamic experiments and to probe the response of materials has motivated the need for special materials optimized for those conditions as well as a need for a much deeper understanding of the behavior of materials subjected to high pressure and/or temperature. Of particular importance is the understanding of rate effects at the extremely high rates encountered in those experiments, especially with the next generation of laser drives such as at the National Ignition Facility. Here we use large-scale molecular dynamics (MD) simulations of the high-rate deformation of nanocrystalline tantalum to investigate the processes associated with plastic deformation for strains up to 100%. We use initial atomic configurations that were produced through simulations of solidification in the work of Streitz et al [Phys. Rev. Lett. 96, (2006) 225701]. These 3D polycrystalline systems have typical grain sizes of 10-20 nm. We also study a rapidly quenched liquid (amorphous solid) tantalum. We apply a constant volume (isochoric), constant temperature (isothermal) shear deformation over a range of strain rates, and compute the resulting stress-strain curves to large strains for both uniaxial and biaxial compression. We study the rate dependence and identify plastic deformation mechanisms. The identification of the mechanisms is facilitated through a novel technique that computes the local grain orientation, returning it as a quaternion for each atom. This analysis technique is robust and fast, and has been used to compute the orientations on the fly during our parallel MD simulations on supercomputers. We find both dislocation and twinning processes are important, and they interact in the weak strain hardening in these extremely fine-grained microstructures.
On the spectrum of field quadratures for a finite number of photons

The spectrum and eigenstates of any field quadrature operator restricted to a finite number N of photons are studied, in terms of the Hermite polynomials. By (naturally) defining approximate eigenstates, which represent highly localized wavefunctions with up to N photons, one can arrive at an appropriate notion of limit for the spectrum of the quadrature as N goes to infinity, in the sense that the limit coincides with the spectrum of the infinite-dimensional quadrature operator. In particular, this notion allows the spectra of truncated phase operators to tend to the complete unit circle, as one would expect. A regular structure for the zeros of the Christoffel–Darboux kernel is also shown.
SOLAR TRANSITION REGION LINES OBSERVED BY THE INTERFACE REGION IMAGING SPECTROGRAPH: DIAGNOSTICS FOR THE O iv AND Si iv LINES

The formation of the transition region O iv and Si iv lines observable by the Interface Region Imaging Spectrograph (IRIS) is investigated for both Maxwellian and non-Maxwellian conditions characterized by a κ-distribution exhibiting a high-energy tail. The Si iv lines are formed at lower temperatures than the O iv lines for all κ. In non-Maxwellian situations with lower κ, the contribution functions are shifted to lower temperatures. Combined with the slope of the differential emission measure, it is possible for the Si iv lines to be formed at very different regions of the solar transition region than the O iv lines; possibly close to the solar chromosphere. Such situations might be discernible by IRIS. It is found that photoexcitation can be important for the Si iv lines, but is negligible for the O iv lines. The usefulness of the O iv ratios for density diagnostics independently of κ is investigated and it is found that the O iv 1404.78 Å/1399.77 Å ratio provides a good density diagnostics except for very low T combined with extreme non-Maxwellian situations.
Nucleation of reaction-diffusion waves on curved surfaces

We study reaction-diffusion waves on curved two-dimensional surfaces, and determine the influence of curvature upon the nucleation and propagation of spatially localized waves in an excitable medium modelled by the generic FitzHugh–Nagumo model. We show that the stability of propagating wave segments depends crucially on the curvature of the surface. As they propagate, they may shrink to the uniform steady state, or expand, depending on whether they are smaller or larger, respectively, than a critical nucleus. This critical nucleus for wave propagation is modified by the curvature acting like an effective space-dependent local spatial coupling, similar to diffuson, thus extending the regime of propagating excitation waves beyond the excitation threshold of flat surfaces. In particular, a negative gradient of Gaussian curvature &Ggr; ? > , as on the outside of a torus surface (positive &Ggr; ? > ), when the wave segment symmetrically extends into the inside (negative &Ggr; ? > ), allows for stable propagation of localized wave segments remaining unchanged in size and shape, or oscillating periodically in size.
PIV in stratified gas-liquid flow in a horizontal pipe using water droplets as tracers in the gas-phase

Simultaneous Particle Image Velocimetry (PIV) measurements of stratified turbulent air/water flow in a horizontal pipe have been performed using water droplets as tracers in the gas-phase. The use of water droplets as tracers ensures that the water surface tension remains unaffected and thus allows small-scale interfacial structures, such as capillary waves to occur naturally. Experiments have been conducted in a 31 m long, 100 mm diameter PVC pipe using air and water as test fluids. For the purpose of validation of the experimental set-up and the suggested seeding technique, single-phase measurements of both air and water were compared to each other and to DNS results from literature, showing very good agreement. The two-phase measurements are presented in terms of mean- and rms-profiles. These measurements offer a qualitative demonstration of the behavior of the interfacial turbulence and its correlation with the various interfacial flow patterns. The observations made in this paper are in agreement with the conclusions drawn from the DNS study of Lakehal et al. (2003). The present results may eventually provide a better explanation to many important phenomena related to the physical characteristics of stratified two-phase flow such as scalar mixing between phases, and to challenges related to its modeling.
STELLAR ARCHAEOLOGY IN THE GALACTIC HALO WITH THE ULTRA-FAINT DWARFS. VI. URSA MAJOR II

We present a B, V color–magnitude diagram (CMD) of the Milky Way dwarf satellite Ursa Major II (UMa II), spanning the magnitude range from V ∼ 15 to V ∼ 23.5 mag and extending over an 18 × 18 arcmin2 area centered on the Galaxy. Our photometry goes down to about 2 mag below the Galaxy's main-sequence turnoff that we detected at V ∼ 21.5 mag. We have discovered a bona fide RR Lyrae variable star in UMa II, which we use to estimate a conservative dereddened distance modulus for the galaxy of (m − M)0 = 17.70 ± 0.04 ± 0.12 mag, where the first error accounts for the uncertainties of the calibrated photometry, and the second reflects our lack of information on the metallicity of the star. The corresponding distance to UMa II is 34.7+0.6−0.7(+2.0−1.9) kpc. Our photometry shows evidence of a spread in the Galaxy's subgiant branch, compatible with a spread in metal abundance in the range between Z = 0.0001 and Z = 0.001. Based on our estimate of the distance, a comparison of the fiducial lines of the Galactic globular clusters M68 and M5 ([Fe/H] = −2.27 ± 0.04 dex and −1.33 ± 0.02 dex, respectively), with the position on the CMD of spectroscopically confirmed Galaxy members, may suggest the existence of stellar populations of different metal abundance/age in the central region of UMa II.
Applications of the Lorentz-Abraham-Dirac equation in long-term dynamics

To improve the presentation we modified the title and used the framework of perturbation modeling of long-term dynamics so as to present the Lorentz-Abraham-Dirac equation as the lowest order, asymptotic differential relation for the velocity of a charged point-like mass. We formulated two propositions and added two references.
Lyα Emitting Galaxies as a Probe of Reionisation

Abstract The Epoch of Reionization (EoR) represents a milestone in the evolution of our Universe. Star-forming galaxies that existed during the EoR likely emitted a significant fraction ( ~ 5 − 40%) of their bolometric luminosity as Lyα line emission. However, neutral intergalactic gas that existed during the EoR was opaque to Lyα emission that escaped from galaxies during this epoch, which makes it difficult to observe. The neutral intergalactic medium (IGM) may thus reveal itself by suppressing the Lyα flux from background galaxies. Interestingly, a ‘sudden’ reduction in the observed Lyα flux has now been observed in galaxies at z > 6. This review contains a detailed summary of Lyα radiative processes: I describe (i) the main Lyα emission processes, including collisional-excitation & recombination (and derive the origin of the famous factor ‘0.68’), and (ii) basic radiative transfer concepts, including e.g. partially coherent scattering, frequency diffusion, resonant versus wing scattering, optically thick versus ‘extremely’ optically thick (static/outflowing/collapsing) media, and multiphase media. Following this review, I derive expressions for the Gunn-Peterson optical depth of the IGM during (inhomogeneous) reionisation and post-reionisation. I then describe why current observations appear to require a very rapid evolution of volume-averaged neutral fraction of hydrogen in the context of realistic inhomogeneous reionisation models, and discuss uncertainties in this interpretation. Finally, I describe how existing & futures surveys and instruments can help reduce these uncertainties, and allow us to fully exploit Lyα emitting galaxies as a probe of the EoR.
Quasiclassical Theory of the Josephson Effect in Ballistic Graphene Junctions

The stationary Josephson effect in a system of ballistic graphene is studied in the framework of quasiclassical Green's function theory. Reflecting the ultimate two-dimensionality of graphene, a Josephson junction involving a graphene sheet embodies what we call a planar Josephson junction, in which superconducting electrodes partially cover the two-dimensional graphene layer, achieving a planar contact with it. For capturing this feature we employ a model of tunneling Hamiltonian that also takes account of the effects of inhomogeneous carrier density. Within the effective mass approximation we derive a general formula for the Josephson current, revealing characteristic features of the superconducting proximity effect in the planar Josephson junction. The same type of analysis has been equally applied to mono-, bi-, and arbitrary N -layer cases.
The Effect of Entrepreneurial Orientation on the Business Performance: Market Orientation as Mediation Variable

Tujuan dari penelitian ini adalah untuk mengukur serta menganalisis pengaruh orientasi kewirausahaan terhadap orientasi pasar, orientasi pasar terhadap kinerja, orientasi kewirausahaan terhadap kinerja serta orientasi kewirausahaan terhadap kinerja yang dimediasi oleh orientasi pasar pada Usaha Kecil Menengah (UKM) sulaman karawo di Gorontalo. Unit analisis dari penelitian ini adalah UKM sulaman karawo di Gorontalo dan data yang digunakan adalah data primer. Populasi dalam penelitian ini adalah seluruh unit UKM sulaman karawo baik yang sudah berbadan hukum maupun yang belum berbadan hukum pada tahun 2021 sejumlah 701 yang tersebar di 6 (enam) kabupaten/kota yang ada di Provinsi Gorontalo. Tekhnik sampling dalam penelitian ini menggunakan pendekatan non probability sampling Dalam penelitian ini digunakan 130 sampel. Alat analisis menggunakan Structural Equation Model (SEM) AMOS. Hasil penelitian ini
massclean (MASSive CLuster Evolution and ANalysis Package): description, tests, and results

Abstract massclean is a new, sophisticated and robust stellar cluster image and photometry simulation package. This package can create color–magnitude diagrams and standard FITS images in any of the traditional optical and near-infrared bands based on cluster characteristics input by the user, including but not limited to distance, age, mass, radius and extinction. At the limit of very distant, unresolved clusters, we have checked the integrated colors created in massclean against those from other simple stellar population models, with consistent results. Because the algorithm populates the cluster with a discrete number of tenable stars, it can be used as part of a Monte Carlo method to derive the probabilistic range of characteristics (integrated colors, for example) consistent with a given cluster mass and age. We present the first ever mass-dependent integrated colors as a function of age, derived from over 100 000 Monte Carlo runs, which can be used to improve the current age-determination methods for stellar clusters.