Miracle-dz/UniFAR-FTUs huggingface dataset:
Extraction of the Schottky parameters in metal-semiconductor-metal diodes from a single current-voltage measurement

In order to develop a method to extract the parameters of the two inherent Schottky contacts from a single current-voltage (I-V) characteristic curve, the I-V characteristics of metal-semiconductor-metal (MSM) diodes with asymmetric Schottky barrier heights are theoretically investigated using the thermionic emission model. The MSM diode structure is commonly used because an additional MS interface is required for the electrical characterization of MS diodes. A finite charge-injection barrier is generally formed at the additional interface. When a local maximum was detected in the first-order derivative of the measured I-V characteristics for a MSM diode, the parameters for the Schottky contacts, the zero-bias barrier heights of both MS interfaces, the series resistance of the MSM diode, and the effective ideality factor for the MS diode with a higher barrier could be extracted using this method.
SPECTRAL AND IMAGING OBSERVATIONS OF A WHITE-LIGHT SOLAR FLARE IN THE MID-INFRARED

We report high-resolution observations at mid-infrared wavelengths of a minor solar flare, SOL2014-09-24T17:50 (C7.0), using Quantum Well Infrared Photodetector cameras at an auxiliary of the McMath-Pierce telescope. The flare emissions, the first simultaneous observations in two mid-infrared bands at 5.2 and 8.2 &mgr; m ? > with white-light and hard X-ray coverage, revealed impulsive time variability with increases on timescales of ∼4 s followed by exponential decay at ∼10 s in two bright regions separated by about 13 ″ ? > . The brightest source is compact, unresolved spatially at the diffraction limit ( 1 &farcs; 72 ? > at 5.2 &mgr; m ? > ). We identify the IR sources as flare ribbons also seen in white-light emission at 6173 Å observed by SDO/HMI, with twin hard X-ray sources observed by Reuven Ramaty High Energy Solar Spectroscopic Imager, and with EUV sources (e.g., 94 Å) observed by SDO/AIA. The two infrared points have nearly the same flux density (fν, W m−2 Hz) and extrapolate to a level of about an order of magnitude below that observed in the visible band by HMI, but with a flux of more than two orders of magnitude above the free–free continuum from the hot (∼15 MK) coronal flare loop observed in the X-ray range. The observations suggest that the IR emission is optically thin; this constraint and others suggest major contributions from a density less than about 4 × 10 13 ? > cm−3. We tentatively interpret this emission mechanism as predominantly free–free emission in a highly ionized but cool and rather dense chromospheric region.
Supersonically Turbulent, Shock Bound Interaction Zones

Shock bound interaction zones (SBIZs) are ubiquitous in astrophysics. We present numerical results for 2D and 3D, plane-parallel, infinitely extended SBIZs. Isothermal settings and parameterized cooling are considered. We highlight and compare characteristic of such zones. We emphasize the mutual coupling between the turbulence within the SBIZ and the confining shocks, point out potential differences to 3D periodic box studies of supersonic turbulence, and contemplate on possible effects on the X-ray emission of such zones.
On the formation of very metal-poor stars: The case of SDSS J1029151+172927

The formation of stars is a key process in the early universe with far‐reaching consequences for further cosmic evolution. While stars forming from truly primordial gas are thought to be considerably more massive than our Sun, stars in the universe today have typical masses below one solar mass. The physical origin of this transition and the conditions under which it occurs are highly debated. There are two competing models: one based on metal‐line cooling as the primary agent and one based on dust cooling. The recent discovery of the extremely metal poor star SDSS J1029151+172927 provides a unique opportunity to distinguish between these two models. Based on simple thermodynamic considerations we argue that SDSS J1029151+172927 was more likely formed as a result of dust continuum cooling rather than cooling by metal lines. We conclude that the masses of extremely metal poor stars are determined by dust‐induced fragmentation.
Deep ensemble with Neural Networks to model power curve uncertainty

Renewable energy is an essential driver towards tackling the climate crisis. Given the increasing need to ensure sustainability and reduce greenhouse gas emissions, wind energy has become one of the most relevant areas to consider in today’s society. However, it appears challenging to rely on this type of energy because of the uncertain nature of the wind. It is essential to use monitoring tools that can accurately capture the uncertainty of the underlying environmental processes and estimate the generated power to ensure the reliability of wind-based power systems. One of these monitoring tools is the power curve, which captures the relationship between wind speed and expected power production. Many regression techniques have previously been used to predict this power production, including Artificial Neural Networks (ANN). The problem is that they do not capture the uncertainty of the predicted power production. In contrast with the power curve models already implemented when using ANNs, we propose a novel approach based on deep ensembles to predict the mean and model variance on the expected power production. We used three months of Supervisory Control and Data Acquisition data from more than 40 turbines to set up the experiments. The results show that the mean and standard deviation fit the data well. It also appears that the expected mean curve goes through the center of the cloud of original data points, while the standard deviation accurately captures the spread of the data. We conclude that that the deep ensemble approach provides an accurate prediction mechanism to estimate the power production from the wind speed while also offering an uncertainty measure. Therefore, the deep ensemble approach allows us to construct a power curve with uncertainty information.
An experimental investigation into the most prominent sources of uncertainty in wave tank testing of floating offshore wind turbines

There is an urgent need to replace carbon-based energy sources with renewable energy sources, and floating offshore wind is seen as a critical component in the drive towards energy diversification. Floating offshore wind facilitates accessing a far vaster wind resource that exists in deeper waters, further offshore. Floating offshore wind platforms must undergo wave tank testing in the early stages of development to assess model responses to different wave and wind conditions. Wave tank testing, while highly beneficial, is liable to have errors arising throughout the testing campaign. Errors can arise during wave tank setup, testing, and analysis of results. One such error is the error in the inertia and centre of gravity (CoG) of the platform. In this research, testing was completed using two very different floating offshore wind concepts. A sensitivity analysis was completed by varying the model inertia and centre of gravity. It was found that the effects of each variation were magnified at resonance, and the magnitude of platform response was affected to a greater extent than the period of resonance response. Of all the variations to the model properties conducted, the inertia about the y-axis and location of the centre of gravity along the x-axis affected pitch response to the greatest extent.
MIGRATION AND GROWTH OF PROTOPLANETARY EMBRYOS. II. EMERGENCE OF PROTO-GAS-GIANT CORES VERSUS SUPER EARTH PROGENITORS

Nearly 15%–20% of solar type stars contain one or more gas giant planets. According to the core-accretion scenario, the acquisition of their gaseous envelope must be preceded by the formation of super-critical cores with masses 10 times or larger than that of the Earth. It is natural to link the formation probability of gas giant planets with the supply of gases and solids in their natal disks. However, a much richer population of super Earths suggests that (1) there is no shortage of planetary building block material, (2) a gas giant's growth barrier is probably associated with whether it can merge into super-critical cores, and (3) super Earths are probably failed cores that did not attain sufficient mass to initiate efficient accretion of gas before it is severely depleted. Here we construct a model based on the hypothesis that protoplanetary embryos migrated extensively before they were assembled into bona fide planets. We construct a Hermite-Embryo code based on a unified viscous-irradiation disk model and a prescription for the embryo-disk tidal interaction. This code is used to simulate the convergent migration of embryos, and their close encounters and coagulation. Around the progenitors of solar-type stars, the progenitor super-critical-mass cores of gas giant planets primarily form in protostellar disks with relatively high (≳ 10−7 M☉ yr−1) mass accretion rates, whereas systems of super Earths (failed cores) are more likely to emerge out of natal disks with modest mass accretion rates, due to the mean motion resonance barrier and retention efficiency.
GSH 006−15+7: a local Galactic supershell featuring transition from H i emission to absorption

We report on the discovery of a new Galactic supershell, GSH 006−15+7, from the Galactic All-Sky Survey data. Observed and derived properties are presented, and we find that GSH 006−15+7 is one of the nearest physically large supershells known, with dimensions of ∼780 × 520 pc at a distance of ∼ 1.5 kpc. The shell wall appears in Hi emission at b≲−65 and in Hi self-absorption (HiSA) at b≳−65. We use this feature along with HiSA diagnostics to estimate an optical depth of τ∼ 3, a spin temperature of ∼40 K and a swept-up mass of M∼ 3 × 106 M⊙. We also investigate the origin of GSH 006−15+7, assessing the energy contribution of candidate powering sources and finding evidence in favour of a formation energy of ∼1052 erg. We find that this structure provides evidence for the transfer of mass and energy from the Galactic disc into the halo.
Leaked GeV CRs from a Broken Shell: Explaining 9 Years of Fermi-LAT Data of SNR W28

Supernova remnant (SNR)W28 is well known for its classic hadronic scenario, in which the TeV cosmic rays (CRs) released at the early stage of this intermediate-age SNR illuminate nearby molecular clouds (MCs). Overwhelming evidence has shown that the northeastern part of the SNR (W28-North) has already encountered the MC clumps. Through this broken shell W28-North, CRs with an energy down to <1 GeV may be able to be injected into nearby MCs. To further verify this hadronic scenario, we first analyze nine years of Fermi-LAT data in/around W28 with energies down to 0.3 GeV. Our Fermi-LAT analysis displays a 10–200 GeV skymap that spatially matches the known TeV sources HESS J1801–233 (W28-North) and HESS J1800–240 A, B, and C (240 A B and C) well. At low energy bands, we have discovered a 0.5–1 GeV blob located to the south of 240 B and C, and a low flux of 0.3–1 GeV at 240 A. A hadronic model is build to explain our analysis results and previous multiwavelength observations of W28. Our model consists of three CR sources: the run-away CRs escaped from a strong shock, the leaked GeV CRs from the broken shell W28-North, and the local CR sea. Through modeling the SNR evolution and the CR acceleration and release, we explain the GeV–TeV emission in/around SNR W28 (except for 240 A) in one model. The damping of the magnetic waves by the neutrals and the decreased acceleration efficiency are both taken into account in our model due to the intermediate age of SNR W28.
DYNAMICAL STUDY OF A1689 FROM WIDE-FIELD VLT/VIMOS SPECTROSCOPY: MASS PROFILE, CONCENTRATION PARAMETER, AND VELOCITY ANISOTROPY

We examine the dynamics structure of the rich cluster A1689, combining VLT/VIMOS spectroscopy with Subaru/Suprime-Cam imaging. The radial velocity distribution of ∼500 cluster members is bounded by a pair of clearly defined velocity caustics, with a maximum amplitude of ∼|4000| km s−1 at ≃ 300 h−1 kpc, beyond which the amplitude steadily declines, approaching zero velocity at a limiting radius of ∼2 h−1 Mpc. We derive the three-dimensional velocity anisotropy and galaxy number density profiles using a model-independent method to solve the Jeans equation, simultaneously incorporating the observed velocity dispersion profile, the galaxy counts from deep Subaru imaging, and our previously derived cluster mass profile from a joint lensing and X-ray analysis. The velocity anisotropy is found to be predominantly radial at large radius, becoming increasingly tangential towards the center, in accord with expectations. We also analyze the galaxy data independently of our previous analysis using two different methods: The first is based on a solution of the Jeans equation assuming an Navarro–Frenk–White (NFW) form for the mass distribution, whereas in the second method the caustic amplitude is used to determine the escape velocity. The cluster virial mass derived by both of these dynamical methods is in good agreement with results from our earlier lensing and X-ray analysis. We also confirm the high NFW concentration parameter, with results from both methods combined to yield cvir > 13 (1σ). The inferred virial radius is consistent with the limiting radius where the caustics approach zero velocity and where the counts of cluster members drop off, suggesting that infall onto A1689 is currently not significant.
Zener tunneling in the electrical transport of quasimetallic carbon nanotubes

We study theoretically the impact of Zener tunneling on the charge-transport properties of quasi-metallic (Qm) carbon nanotubes (characterized by forbidden band gaps of few tens of meV). We also analyze the interplay between Zener tunneling and elastic scattering on defects. To this purpose we use a model based on the master equation for the density matrix, that takes into account the inter-band Zener transitions induced by the electric field (a quantum mechanical effect), the electron-defect scattering and the electron-phonon scattering. In presence of Zener tunnelling the Qm tubes support an electrical current even when the Fermi energy lies in the forbidden band gap. In absence of elastic scattering (in high quality samples), the small size of the band gap of Qm tubes enables Zener tunnelling for realistic values of the the electric field (above $\sim$ 1 V/\mu m). The presence of a strong elastic scattering (in low quality samples) further decreases the values of the field required to observe Zener tunnelling. Indeed, for elastic-scattering lengths of the order of 50 nm, Zener tunnelling affects the current/voltage characteristic already in the linear regime. In other words, in quasi-metallic tubes, Zener tunneling is made more visible by defects.
THE FUTURE OF THE SUN: AN EVOLVED SOLAR TWIN REVEALED BY CoRoT

The question of whether the Sun is peculiar within the class of solar-type stars has been the subject of active investigation over the past three decades. Although several solar twins have been found with stellar parameters similar to those of the Sun (albeit in a range of Li abundances and with somewhat different compositions), their rotation periods are unknown, except for 18 Sco, which is younger than the Sun and with a rotation period shorter than solar. It is difficult to obtain rotation periods for stars of solar age from ground-based observations, as a low-activity level implies a shallow rotational modulation of their light curves. CoRoT has provided space-based long time series from which the rotation periods of solar twins as old as the Sun could be estimated. Based on high-signal-to-noise, high-resolution spectroscopic observations gathered at the Subaru Telescope, we show that the star CoRoT ID 102684698 is a somewhat evolved solar twin with a low Li abundance. Its rotation period is 29 ± 5 days, compatible with its age (6.7 Gyr) and low lithium content, ALi ≲ 0.85 dex. Interestingly, our CoRoT solar twin seems to have enhanced abundances of the refractory elements with respect to the Sun, a typical characteristic of most nearby twins. With a magnitude V ≃ 14.1, ID 102684698 is the first solar twin revealed by CoRoT, the farthest field solar twin so far known, and the only solar twin older than the Sun for which a rotation period has been determined.
The X-ray dust-scattered rings of the black hole low-mass binary V404 Cyg

We report on the first detection of X-ray dust scattered rings from the Galactic low mass X-ray binary V404 Cyg. The observation of the system with Swift/XRT on June 30 2015 revealed the presence of five concentric ring-like structures centred at the position of V404 Cyg. Follow-up Swift/XRT observations allowed a time-dependent study of the X-ray rings. Assuming that these are the result of small-angle, single X-ray scattering by dust grains along the line of sight, we find that their angular size scales as $\theta \propto\sqrt{t}$ in agreement with theoretical predictions. The dust grains are concentrated in five dust layers located at about 2.12, 2.05, 1.63, 1.50 and 1.18 kpc from the observer. These coincide roughly with locations of enhanced extinction as determined by infrared photometry. Assuming that the grain size distribution is described by a generalized Mathis-Rumpl-Nordsieck model, we find that the power-law index of the most distant cloud is $q\sim 4.4$, while $q \sim 3.5-3.7$ in all other clouds. We constrain at a $3\sigma$ level the maximum grain size of the intermediate dust layers in the range $0.16-0.20\,\mu$m and set a lower limit of $\sim 0.2\,\mu$m in the other clouds. Hints of an exponential cutoff at the angular intensity profile of the outermost X-ray ring suggest that the smallest grains have sizes $0.01 \mu{\rm m}\le \alpha_{\min} \lesssim 0.03\,\mu$m. Based on the relative ratios of dust column densities we find the highest dust concentration at $\sim 1.6$ kpc. Our results indicate a gradient in the dust properties within 1 kpc from V404 Cyg.
A comprehensive multiphonon spectral analysis in MoS2

We present a comprehensive multiphonon Raman and complementary infrared analysis for bulk and monolayer MoS2. For the bulk the analysis consists of symmetry assignment from which we obtain a broad set of allowed second-order transitions at the high symmetry M, K and Γ Brillouin zone (BZ) points. The attribution of about 80 transitions of up to fifth order processes are proposed in the low temperature (95 K) resonant Raman spectrum measured with excitation energy of 1.96 eV, which is slightly shifted in energy from the A exciton. We propose that the main contributions come from four phonons: A1g (M), E12g (M1), E22g (M1) (TA′ (M)) and E22g (M2) (LA′ (M)). The last three are single degenerate phonons at M with an origin of the E12g (Γ) and E22g (Γ) phonons. Among the four phonons, we identify in the resonant Raman spectra all (but one) of the second-order overtones, combination and difference-bands and many of the third order bands. Consistent with the expectation that at the M point only combinations with the same inversion symmetry (g or u) are Raman-allowed, the contribution of combinations with the longitudinal acoustic (LA(M)) mode can not be considered with the above four phonons. Although minor, contributions from K point and possibly Γ-point phonons are also evident. The ‘2LA band’, measured at ∼460 cm−1 is reassigned. Supported by the striking similarity between this band, measured under off-resonant conditions, and recently published two phonon density of states, we explain the lower part of the band, previously attributed to 2LA(M), as being due to a van Hove singularity between K and M. The higher part, previously attributed exclusively to the A2u (Γ) phonon, is mostly due to the LA and LA′ phonons at M. For the monolayer MoS2 the second-order phonon processes from the M and Γ BZ points are also analyzed and are discussed within similar framework to that of the bulk.
THE X-RAY PROPERTIES OF FIVE GALACTIC SUPERNOVA REMNANTS DETECTED BY THE SPITZER GLIMPSE SURVEY

We present a study of the X-ray properties of five Galactic supernova remnants (SNRs)—Kes 17 (G304.6+0.1), G311.5−0.3, G346.6−0.2, CTB 37A (G348.5+0.1), and G348.5−0.0—that were detected in the infrared by Reach et al. in an analysis of data from the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) that was conducted by the Spitzer Space Telescope. We present and analyze archival ASCA observations of Kes 17, G311.5−0.3, and G346.6−0.2, archival XMM-Newton observations of Kes 17, CTB 37A, and G348.5−0.0, and an archival Chandra observation of CTB 37A. All of the SNRs are clearly detected in the X-ray except possibly G348.5−0.0. Our study reveals that the four detected SNRs all feature center-filled X-ray morphologies and that the observed emission from these sources is thermal in all cases. We argue that these SNRs should be classified as mixed-morphology SNRs (MM SNRs); our study strengthens the correlation between MM SNRs and SNRs interacting with molecular clouds and suggests that the origin of MM SNRs may be due to the interactions between these SNRs and adjacent clouds. Our ASCA analysis of G311.5−0.3 reveals for the first time X-ray emission from this SNR: the X-ray emission is center-filled within the radio and infrared shells and thermal in nature (kT ∼ 0.98 keV), thus motivating its classification as an MM SNR. We find considerable spectral variations in the properties associated with the plasmas of the other X-ray-detected SNRs, such as a possible overabundance of magnesium in the plasma of Kes 17. Our new results also include the first detailed spatially resolved spectroscopic study of CTB 37A using Chandra as well as a spectroscopic study of the discrete X-ray source CXOU J171428.5−383601, which may be a neutron star associated with CTB 37A. Finally, we also estimate such properties as electron density ne, radiative age trad and swept-up mass MX for each of the four X-ray-detected SNRs. Each of these values are comparable to archetypal MM SNRs like 3C 391 and W44. In an analysis of the spectrum of Kes 17, we did not find evidence of overionization unlike other archetypal MM SNRs like W44 and W49B.
Oxygen, $\alpha$-element and iron abundance distributions in the inner part of the Galactic thin disc. II

We have derived the abundances of 36 chemical elements in one Cepheid star, ASAS 181024--2049.6, located R$_{\rm G}= 2.53$ kpc from the Galactic center. This star falls within a region of the inner thin disc poorly sampled in Cepheids. Our spectral analysis shows that iron, magnesium, silicon, calcium and titanium LTE abundances in that star support the presence of a plateau-like abundance distribution in the thin disc within 5 kpc of the Galactic center, as previously suggested by \cite{Maret15}. If confirmed, the flattening of the abundance gradient within that region could be the result of a decrease in the star formation rate due to dynamic effects, possibly from the central Galactic bar.