Miracle-dz/UniFAR-FTUs huggingface dataset:
Spin and orbital magnetic response on the surface of a topological insulator

Coupling of the spin and orbital degrees of freedom on the surface of a strong three-dimensional insulator, on the one hand, and textured magnetic configuration in an adjacent ferromagnetic film, on the other, is studied using a combination of transport and thermodynamic considerations. Expressing exchange coupling between the localized magnetic moments and Dirac electrons in terms of the electrons' out-of-plane orbital and spin magnetizations, we relate the thermodynamic properties of a general ferromagnetic spin texture to the physics in the zeroth Landau level. Persistent currents carried by Dirac electrons endow the magnetic texture with a Dzyaloshinski-Moriya interaction, which exhibits a universal scaling form as a function of electron temperature, chemical potential, and the time-reversal symmetry breaking gap. In addition, the orbital motion of electrons establishes a direct magnetoelectric coupling between the unscreened electric field and local magnetic order, which furnishes complex long-ranged interactions within the magnetic film.
Quadratic isocurvature cross-correlation, Ward identity, and dark matter

Sources of isocurvature perturbations and large non-Gaussianities include field degrees of freedom whose vacuum expectation values are smaller than the expansion rate of inflation. The inhomogeneities in the energy density of such fields are quadratic in the fields to leading order in the inhomogeneity expansion. Although it is often assumed that such isocurvature perturbations and inflaton-driven curvature perturbations are uncorre- lated, this is not obvious from a direct computational point of view due to the form of the minimal gravitational interactions. We thus compute the irreducible gravitational contributions to the quadratic isocurvature-curvature cross-correlation. We find a small but non-decaying cross-correlation, which in principle serves as a consistency prediction of this large class of isocurvature perturbations. We apply our cross-correlation result to two dark matter isocurvature perturbation scenarios: QCD axions and WIMPZILLAs. On the technical side, we utilize a gravita- tional Ward identity in a novel manner to demonstrate the gauge invariance of the computation. Furthermore, the detailed computation is interpreted in terms of a soft-{\zeta} theorem and a gravitational Ward identity. Finally, we also identify explicitly all the counterterms that are necessary for renormalizing the isocurvature perturbation composite operator in inflationary cosmological backgrounds.
CLASSICAL Oe STARS IN THE FIELD OF THE SMALL MAGELLANIC CLOUD

We present 29 ± 1 classical Oe stars from RIOTS4 (the Runaways and Isolated O Type Star Spectroscopic Survey of the SMC), a spatially complete, spectroscopic survey of Small Magellanic Cloud (SMC) field OB stars. The two earliest are O6e stars, and four are earlier than any Milky Way (MW) Oe stars. We also find ten Ope stars, showing He i infill and/or emission; five appear to be at least as hot as ∼O7.5e stars. The hottest, star 77616, shows He ii disk emission, suggesting that even the hottest O stars can form decretion disks, and offers observational support for theoretical predictions that the hottest, fastest rotators can generate He+-ionizing atmospheres. Our data also demonstrate that Ope stars correspond to Oe stars earlier than O7.5e with strong disk emission. We find that in the SMC, Oe stars extend to earlier spectral types than in the MW, and our SMC Oe/O frequency, 0.26 ± 0.04, is much greater than the MW value, 0.03 ± 0.01. These results are consistent with angular momentum transport by stronger winds suppressing decretion disk formation at higher metallicity. In addition, the Oe star frequency in the SMC field is indistinguishable from that for clusters, which is consistent with the similarity between rotation rates in these environments, and contrary to the pattern for MW rotation rates. Thus, our findings strongly support the viscous decretion disk model and confirm that Oe stars are the high-mass extension of the Be phenomenon. Additionally, we find that Fe ii emission occurs among Oe stars later than O7.5e with massive disks, and we revise a photometric criterion for identifying Oe stars to J − [ 3.6 ] ≥ 0.1 ? > .
A low supply voltage sensitivity low power oscillator design

With the rapid development of social economy, the integrated circuit industry has developed rapidly. At the same time, people’s requirements for the cost, power consumption, integration, stability and other aspects of integrated circuit chips have increased. Oscillators, as an important module for providing clocks to chips, have higher requirements for on-chip oscillators. The purpose of this paper is to achieve a low supply voltage sensitive and low power oscillator. Based on this research purpose, this paper proposes a power adjustment oscillator circuit of the flip level technique, which realizes that the clock signal duty cycle is 50% under the typical case of a supply voltage of 4 V. The center frequency is 512 KHz, of which the process angle trimming range of the capacitor trim circuit is 52.37%-211.28%. With the supply voltage range of 2.5 V to 5.5 V, the clock signal has a frequency variation of 0.299%/V, has low supply voltage sensitivity, and consumes only 400 nA with low power dissipation.
Detection method of water channel defects in engine block based on deep learning

Aiming at the low efficiency of manual detection in the detection of water channel defects of engine cylinder block and the poor generalization ability of traditional machine vision in manual design features, an improved water channel defect detection model of cylinder block based on fast RCNN network is proposed. Restnet50 is selected as the feature extraction network of waterway defects, and feature pyramid network (FPN) is introduced to improve the detection ability of small defects; The anchor box is optimized by k-means++ clustering algorithm to improve the positioning of the target box. Experiments show that the map of the improved network in the engine cylinder block waterway defect data set reaches 88.74%, the accuracy is increased by 4% compared with the original fast RCNN, and the recall rate is increased by 1.67%. The recognition and detection effect in real samples is good, and it can be effectively used for the engine cylinder block waterway defect detection.
The Schwarzschild's Braneworld Solution

In the context of the Randall–Sundrum braneworld, the minimal geometric deformation approach, which has been successfully used to generate exact interior solutions to Einstein's field equations for static braneworld stars with local and nonlocal bulk terms, is used to obtain the braneworld version of the Schwarzschild's interior solution. Using this new solution, the behavior of the Weyl functions is elucidated in terms of the compactness for different stellar distributions.
U-duality invariant dyon spectrum in type II on T 6

We give a manifestly U-duality invariant formula for the degeneracy of 1/8 BPS dyons in type II string theory on T6 for a U-duality invariant subset of charge vectors. Besides depending on the Cremmer-Julia invariant the degeneracy also depends on other discrete invariants of E7(7)().
Sensitivity of structural and electronic properties of Li-ion battery cathode materials to Hubbard U correction: an efficient first-principle approach

A new material design approach using first-principles density functional theory (DFT) calculations with acceptable precision can elucidate many critical features in emerging high-performance lithium-ion battery fields. However, the dominant impact of transition metals (TM) as the major component and/or modification dopant element with localized d-electrons in this material system, which needs so-called Hubbard correction U, limits DFT to many extents. As the U correction is not completely transferable, one may need to recalculate it for the same input structure with structural or elemental changes. While the accurate calculation of U is costly, it is worth investigating its sensitivity to input system parameters, such as cell size, structure, and chemical composition, to dismiss unessential recalculations, especially in high-throughput schemes. Furthermore, implementing DFT + U to get the expected properties is computationally expensive too. The necessity of including the U correction for expected properties or its small variation should be investigated. In this study, Hubbard correction for TM using a density functional perturbation theory (DFPT) approach was considered to investigate the electronic structure and structural stability of LiNiO2, LiCoO2, and LiNi0.75Co0. 167Al0.083O2. The effect of system parameters (cell size, structure, and chemical composition) on U values was considered for different systems. The dependency of calculated electronic densities of states, lattice parameters, preferred doping sites, and vacancy formation energy, as well as charge voltage, was investigated, and low and high sensitivities were discussed. Furthermore, the effect of different doping scenarios with Co and Al on structural stability was studied with the efficient DFT + U approach. The results showed that the structural variation due to doping and vacancy site formation has a negligible effect on calculated U values. Significant correlation of predicted electronic properties with U for all systems was observed, while calculated lattice parameters, as well as preferred doping sites, reflected very low dependency on U variations.
Optimal Design of a Cable Driven Parallel Robot for Upper Limb Rehabilitations

A novel cable driven parallel robot is introduced to assist upper limb in rehabilitation treatments in this paper, which has a lightweight structure. This robot is characterized by a novel and flexible end-effector that is easy to change assembly for different therapies. And it is designed for desktop usage, so its size is not too large. After presenting the structure, the kinematic model is presented for optimal design. Then, the minimal singular value is considered as the velocity transmission index. For upper limb rehabilitation, a new optimal design problem with the transmission index and the robot size is formulated. Last, the optimization presents a design with satisfying performances in velocity transmission capability and robot size.
Magnetic Properties of Two-dimensional Nanodots: Ground State and Phase Transition

We study the effect of perpendicular single-ion anisotropy, −Asz2, on the ground-state structure and finite-temperature properties of a two-dimensional magnetic nanodot in presence of a dipolar interaction of strength D. By a simulated annealing Monte Carlo method, we show that in the ground state a vortex core perpendicular to the nanodot plane emerges already in the range of moderate anisotropy values above a certain threshold level. In the giant-anisotropy regime the vortex structure is superseded by a stripe domain structure with stripes of alternate domains perpendicular to the surface of the sample. We have also observed an intermediate stage between the vortex and stripe structures, with satellite regions of tilted nonzero perpendicular magnetization around the core. At finite temperatures, at small A, we show by Monte Carlo simulations that there is a transition from the the in-plane vortex phase to the disordered phase characterized by a peak in the specific heat and the vanishing vortex order pa.
Limits on lepton flavor violation from mu(-)-e(-) conversion

We revisit the status of Lepton Flavor Violating (LFV) \mu e qq contact interactions from the view point of \mu - e -conversion in nuclei. We consider their contribution to this LFV process via the two mechanisms on the hadronic level: direct nucleon and meson exchange ones. In the former case the quarks are embedded directly into the nucleons while in the latter in mesons which then interact with nucleons in a nucleus. We revise and in some cases reevaluate the hadronic parameters relevant for both mechanisms and calculate the contribution of the above mentioned contact interactions in coherent \mu - e -conversion in various nuclei. Then we update the existing upper bounds and also derive new ones for the scales of the \mu e qq contact interactions from the experimental limits on the capture rates of \mu - e -conversion. We compare these limits with the ones derived in the literature from other LFV processes and comment on the prospects of LHC searches related to the contact \mu e qq interactions.
Silica nanofillers-reinforced polyimide composites for mechanical, thermal, and electrical insulation applications and recommendations: a review

Owing to the specific properties of polyimide, its nanocomposites have in recent years shown to be a promising polymer composite for mechanical, thermal, and electrical insulation applications. Studies have in many ways revealed the utilization of the polyimide reinforced nanofillers in the area of insulation practice be it thermal or electrical insulation. However, reinforced polyimide nanocomposites were observed to undergo interfacial bonding issues that have badly influenced their insulation behaviour during service. Dielectric properties and electrical discharge (corona discharge) resistance lifespan of polyimide composites are found degrading during long periods of exposure to elevated temperature conditions. Notwithstanding, efforts have been made on improving the electrical and thermal insulation behaviour of polyimide nanocomposites. As such, the current review study focused on the influence of silica nanoparticles on the thermal, electrical, and mechanical characteristics of polyimide matrix composites for insulation practice and applications. Thus, the vision of the authors is to contribute to the future trend of designing and processing polyimide nanocomposites for insulation applications. Thus, the authors ended the article with furtherance, challenges, and recommendations of further enhancement of polyimide nanocomposites as a candidate material for insulation (electrical and thermal). Hence, the study will pave the way for future studies.
Evolutionary influences on the structure of red-giant acoustic oscillation spectra from 600d of Kepler observations

Context. The Kepler space mission is reaching continuous observing times long enough to also start studying the fine structure of the observed pressure-mode spectra. Aims. In this paper, we aim to study the signature of stellar evolut ion on the radial and pressure-dominated l = 2 modes in an ensemble of red giants that show solar-type oscillations. Methods. We use established methods to automatically identify the mode degree of l = 0 and 2 modes and measure the large (�νc) and small (δν02) frequency separation around the central radial mode. We then determine the phase shiftǫc of the central radial mode, i.e. the linear offset in the asymptotic fit to the acoustic modes. Furthermore w e measure the individual frequencies of radial modes and investigate their average curvature. Results. We find that ǫc is significantly di fferent for red giants at a given �νc but which burn only H in a shell (RGB) than those that have already ignited core He burning. Even though not directly probing the stellar core the pair of local seismic observa bles (�νc,ǫc) can be used as an evolutionary stage discriminator that turn ed out to be as reliable as the period spacing of the mixed dipole modes. We find a tight correlation between ǫc and �νc for RGB stars and unlike less evolved stars we find no indicati on thatǫc depends on other properties of the star. It appears that the difference inǫc between the two populations becomes smaller and eventually indistinguishable if we use an average of several radial orders, instead of a loc al, i.e. only around the central radial mode, large separati on to determine the phase shift. This indicates that the information on the e volutionary stage is encoded locally, more precisely in the shape of the radial mode sequence. This shape turns out to be approximately symmetric around the central radial mode for RGB stars but asymmetric for core He burning stars. We computed radial mode frequencies for a sequence of red-giant models and find them to qualitat ively confirm our findings. We also find that, at least in our models, t he local �ν is an at least as good and mostly better proxy for both the asymptotic spacing and the large separation scaled from the model density than the average �ν. Finally, we investigate the signature of the evolutionary stage onδν02 and quantify the mass dependency of this seismic parameter.
The Calabi conjecture and K-stability

We algebraically prove K-stability of polarized Calabi–Yau varieties and canonically polarized varieties with mild singularities. In particular, the “stable varieties” introduced by Kollar–Shepherd-Barron [“Threefolds and deformation of surface singularities. ” Inventiones Mathematicae 91 (1988): 299–338] and Alexeev [“Moduli spaces M g,n (W) for surfaces. ” Proceeding of “Higher-dimensional complex varieties (Trento, 1994)”, de Gruyter, Berlin, 1996, 1–22], which form compact moduli space, are proven to be K-stable although it is well known that they are not necessarily asymptotically (semi) stable. As a consequence, we have orbifold counterexamples to the folklore conjecture “K-stability implies asymptotic stability”. They have Kahler–Einstein (orbifold) metrics, so the result of Donaldson [“Scalar curvature and projective embeddings. I. ” Journal of Differential Geometry 59, no. 3 (2001): 479–522] does not hold for orbifolds.
DOPPLER SHIFT OF THE QUIET REGION MEASURED BY MERIDIONAL SCANS WITH THE EUV IMAGING SPECTROMETER ON BOARD HINODE

Spatially averaged ( > 50 ″ ? > ) EUV spectral lines in the transition region of solar quiet regions are known to be redshifted. Because the mechanism underlying this phenomenon is unclear, we require additional physical information on the lower corona in order to limit the theoretical models. To acquire this information, we measured the Doppler shifts over a wide coronal temperature range ( log T [ K ] = 5.7 ? > –6.3) using the spectroscopic data taken by the Hinode EUV Imaging Spectrometer. By analyzing the data over the center-to-limb variations covering the meridian from the south to the north pole, we successfully measured the velocity to an accuracy of 3 km s - 1 ? > . Below log T [ K ] = 6.0 , ? > the Doppler shifts of the emission lines were almost zero with an error of 1–3 km s - 1 ? > ; above this temperature, they were blueshifted with a gradually increasing magnitude, reaching − 6.3 ± 2.1 km s - 1 ? > at log T [ K ] = 6.25 . >
Highly Reproducible Heterosynaptic Plasticity Enabled by MoS2/ZrO2-x Heterostructure Memtransistor.

Electrically tunable resistive switching of a polycrystalline MoS2-based memtransistor has attracted a great deal of attention as an essential synaptic component of neuromorphic circuitry because its switching characteristics from the field-induced migration of sulfur defects in the MoS2 grain boundaries can realize multilevel conductance tunability and heterosynaptic functionality. However, reproducible switching properties in the memtransistor are usually disturbed by the considerable difficulty in controlling the concentration and distribution of the intrinsically existing sulfur defects. Herein, we demonstrate reliable heterosynaptic characteristics using a memtransistor device with a MoS2/ZrO2-x heterostructure. Compared to the control device with the MoS2 semiconducting channel, the Schottky barrier height was more effectively modulated by the insertion of the insulating ZrO2-x layer below the MoS2, confirmed by an ultraviolet photoelectron spectroscopy analysis and the corresponding energy-band structures. The MoS2/ZrO2-x memtransistor accomplishes dual-terminal (drain and gate electrode) stimulated multilevel conductance owing to the tunable resistive switching behavior under varying gate voltages. Furthermore, the memtransistor exhibits long-term potentiation/depression endurance cycling over 7000 pulses and stable pulse cycling behavior by the pulse stimulus from different terminal regions. The promising candidate as an essential synaptic component of the MoS2/ZrO2-x memtransistors for neuromorphic systems results from the high recognition accuracy (∼92%) of the deep neural network simulation test, based on the training and inference of handwritten numbers (0-9). The simple memtransistor structure facilitates the implementation of complex neural circuitry.
Probing the stability of superheavy dark matter particles with high-energy neutrinos

Two of the most fundamental properties of the dark matter particle, the mass and the lifetime, are only weakly constrained by the astronomical and cosmological evidence of dark matter. We derive in this paper lower limits on the lifetime of dark matter particles with masses in the range 10TeV−1015TeV from the non-observation of ultrahigh energy neutrinos in the AMANDA, IceCube, Auger and ANITA experiments. For dark matter particles which produce neutrinos in a two body or a three body leptonic decay, we find that the dark matter lifetime must be longer than (1026−1028)s for masses between 10 TeV and the Grand Unification scale. Finally, we also calculate, for concrete particle physics scenarios, the limits on the strength of the interactions that induce the dark matter decay.
Strain-induced van der Waals gaps in GeTe revealed by in situ nanobeam diffraction

Ordered germanium vacancies in germanium telluride thermoelectric material are called van der Waals (vdW) gaps, and they are beneficial for the thermoelectric performance of the material. The vdW gaps have been observed by atomic resolution scanning transmission electron microscopy, but their origin remains unclear, which prevents their extensive application in other materials systems. Here, we report that the occurrence of vdW gaps in germanium telluride is mainly driven by strain from the cubic-to-rhombohedral martensitic transition. Direct strain and structural evidence are given here by in situ nanobeam diffraction and in situ transmission electron microscopy observation. Dislocation theory is used to discuss the origin of vdW gaps. Our work here paves the way for self-assembling two-dimensional ordered vacancies, which establishes a previously unidentified degree of freedom to adjust their electronic and thermal properties.
Conformal quantum mechanics and Fick-Jacobs equation

It is found a relation between conformal quantum mechanics and Fick-Jacobs equation, which describes diffusion in channels. This relation is given between a family of channels and a family of conformal Hamiltonians. In addition, it is shown that a conformal Hamiltonian is associated with two channels with different geometry. Furthermore exact solutions for Fick-Jacobs equation are given for this family of channels.
Pulse-wise Amati correlation in Fermi gamma-ray bursts

We make a detailed pulse-wise study of gamma-ray bursts (GRBs) with known redshift detected by \emph{Fermi}/Gamma Ray Burst Monitor (GBM). The sample contains 19 GRBs with 43 pulses. We find that the average peak energy is correlated to the radiated energy (the Amati relation) for individual pulses with a correlation coefficient of 0.86, which is slightly better than the correlation for the full GRBs. As the present correlation holds within GRBs, it is a strong evidence supporting the reliability of such a correlation. We investigate several aspects of this correlation. (i) We divide our sample into redshift bins and study the evolution of the correlation. Though there is a marginal indication of evolution of the correlation, we can conclude that the present data is consistent with no evolution. (ii) We compare the correlation in the first or single pulses of these GRBs to that of the rest of the pulses, and confirm that the correlation is unaffected by the fact that first/single pulses are generally harder than the rest. Finally, we conclude that the pulse-wise Amati correlation is more robust and it has the potential of refining the correlation so that GRB study could be used as a cosmological tool.