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2017-10-26
SDSS J090152.05+624342.6: A New "Overlapping-Trough" FeLoBAL Quasar At Z$\sim2$
We here report an identification of SDSS J090152.04+624342.6 as a new "overlapping-trough" iron low-ionization broad absorption line quasar at redshift of $z\sim2.1$. No strong variation of the broad absorption lines can be revealed through the two spectra taken by the Sloan Digital Sky Survey with a time interval of $...
1710.09527v1
2017-11-03
Supernova β^- decay of nuclides 53Fe, 54Fe, 55Fe, and 56Fe in strongly screened plasma
The electron screening strong effect on the electron energy and threshold energy of the beta decay reaction. in this paper, we study the $\beta^-$ decay rates of some iron isotopes. The electron screening beta decay rates increase by about two orders of magnitude. The strong screening beta decay rates due to Q-value co...
1711.01955v3
2017-11-29
The Memory Function Formalism: A Review
An introduction to the Zwanzig-Mori-G\"{o}tze-W\"{o}lfle memory function formalism (or generalized Drude formalism) is presented. This formalism is used extensively in analyzing the experimentally obtained optical conductivity of strongly correlated systems like cuprates and Iron based superconductors etc. For a broade...
1711.10758v1
2017-11-30
A note on the contribution of multi-photon processes to radiative opacity
Recently, Bailey et al. performed iron opacity measurements on the Z machine at Sandia National Laboratory in conditions close to the ones of the base of the convective zone of the Sun. Such experiments have raised questions about the physical models commonly used in opacity codes. To understand the discrepancy between...
1711.11295v1
2017-12-10
Visible evidence to magnetism of graphene oxide
Graphene oxide continues to amaze scientific community for multiple potentials in a broad span of applications such as catalysts, adsorbents, oxidants, etc., determined by constant unveiling of its fantastic natures. Of them, magnetism is not ultimately identified and directly observed by naked eyes. Herein, we report ...
1712.03570v4
2017-12-22
Novel Method for Background Phase Removal on MRI Proton Resonance Frequency Measurements
MR images have a magnitude and a phase, but in almost all clinical applications only the magnitude images are used, because the phase images have a smooth but strong background signal that masks useful information. The phase contains information such as the temperature during thermal ablation, and the iron content of b...
1712.08651v1
2018-02-23
Electronic entropy in Green's-function calculations at finite temperatures
We revise critically existing approaches to evaluation of thermodynamic potentials within the Green's function calculations at finite electronic temperatures. We focus on the entropy and show that usual technical problems related to the multivalued nature of the complex logarithm can be overcome. This results in a simp...
1802.08495v1
2018-03-01
High Temperature Electronic Structure with KKR
Modeling high temperature (10's or 100's of eV), dense plasmas is challenging due to the multitude of non-negligible physical effects including significant partial ionization and multi-site effects. These effects cause the breakdown or intractability of common methods and approximations used at low temperatures, such a...
1803.00596v1
2018-03-18
Effect of gap anisotropy on the spin resonance peak in the superconducting state of iron-based materials
Spin resonance in the superconducting state of Fe-based materials within the multiorbital model with unequal anisotropic gaps on different Fermi surface sheets is studied. On the basis of the model gap function and the one calculated within the spin fluctuation theory of pairing, I show that the resonance peak shifts t...
1803.06736v2
2018-05-03
Binarizer at SemEval-2018 Task 3: Parsing dependency and deep learning for irony detection
In this paper, we describe the system submitted for the SemEval 2018 Task 3 (Irony detection in English tweets) Subtask A by the team Binarizer. Irony detection is a key task for many natural language processing works. Our method treats ironical tweets to consist of smaller parts containing different emotions. We break...
1805.01112v1
2018-05-15
Nuclear EMC effect through $\barΛ/Λ$ production in semi-inclusive deep-inelastic scattering processes
We calculate $\Lambda$ and $\bar{\Lambda}$ hadron production cross sections in charged lepton semi-inclusive deep-inelastic scattering off nuclear target ($A$, using iron $\mathrm{Fe}$ as an example) and deuteron ($D$) target. The results show that the ratio $(\bar{\Lambda}^{A}/\Lambda^{A})/(\bar{\Lambda}^{D}/\Lambda^{...
1805.05544v1
2018-05-16
Lattice distortions and/or intercalation as ways to induce magnetism in a-FeSi2: a theoretical study
The possibilities to induce magnetism in the non-magnetic bulk alpha-FeSi2 by means of lattice distortions or intercalation with metal or non-metal ions of light elements is investigated theoretically by combined ab initio and model methods. We find that the distortions indeed can induce the formation of magnetic momen...
1805.06189v1
2018-05-25
Pairing Mechanism in Hunds Metal Superconductors and the Universality of the Superconducting Gap to Critical Temperature Ratio
We analyze a simple model containing the physical ingredients of a Hund's metal, the local spin fluctuations with power-law correlators, $(\Omega_0/|\Omega|)^\gamma$, with $\gamma$ greater than one, interacting with electronic quasiparticles. While the critical temperature and the gap change significantly with varying ...
1805.10280v2
2018-05-30
Charged and Neutral Current Pion Production in Neutrino-Nucleus Scattering
In this article, we present the charged and neutral current coherent pion production in the neutrino-nucleus interaction in the resonance region using the formalism based on the partially conserved axial current (PCAC) theorem which relates the neutrino-nucleus cross section to the pion-nucleus elastic cross section. T...
1805.11836v1
2018-06-08
The Role of Opacities in Stellar Pulsation
We examine the role of opacities in stellar pulsation with reference to Cepheids and RR Lyraes, and examine the effect of augmented opacities on the theoretical pulsation light curves in key temperature ranges. The temperature ranges are provided by recent experimental and theoretical work that have suggested that the ...
1806.02996v1
2018-08-01
Long range dynamical coupling between magnetic adatoms mediated by a 2D topological insulator
We study the spin excitation spectra and the dynamical exchange coupling between iron adatoms on a Bi bilayer nanoribbon. We show that the topological character of the edge states is preserved in the presence of the magnetic adatoms. Nevertheless, they couple significantly to the edge spin currents, as witnessed by the...
1808.00347v1
2018-08-07
Origin of superconductivity in Ni-doped SrFe_2As_2 , an Insight from DMFT
I describe the issues of the competing orders in normal state of a parent and Ni-doped iron pnictide superconductor, SrF e 2 As 2 , using LMTO band structure calculation plus multi orbital dynamical mean-field theory. Strong, electronic correlations along with minimal antiferromagnetic instability create a partially ga...
1808.02298v1
2019-11-12
Classification of materials with phonon angular momentum and microscopic origin of angular momentum
We group materials into five symmetry classes and determine in which of these classes phonons carry angular momentum in the Brillouin zone, away from a high-symmetry point, line, or plane. In some materials phonons acquire angular momentum via the forces induced by relative displacements of atoms out of their equilibri...
1911.05064v3
2020-01-27
Influence of Iron Losses on Switching Dynamics of an Electromagnet from Experiment and Simulation
The switching behaviour of electromagnets is determined by the inertia of the armature, the stiffness of the return spring and the magnetostatic forces between armature and yoke. For highly dynamic systems, hysteresis and eddy current losses have a slowing effect. In this paper we consider the experimentally observed b...
2001.09638v1
2020-05-21
Cluster Dynamics Modeling of Niobium and Titanium Carbide Precipitates
Kinetics of niobium and titanium carbide precipitates in iron has been simulated with cluster dynamics. The simulations, carried out in austenite and ferrite for niobium carbides, respectively in austenite for titanium carbide, were analyzed for dependency on temperature, solute concentration, and initial cluster distr...
2005.10574v2
2020-07-12
Reconstruction of 3D Image of Nanorice Particle from Randomly Oriented Single-Shot Experimental Diffraction Patterns Using Angular Correlation Method
We reconstructed intensities in Fourier space and electron densities in the real space for an azimuthally symmetric object Nanorice particle (Iron Oxide nanoparticle) exposed in the ultrashort, bright and coherent x-ray free electron laser (XFEL) pulses with random unknown orientations through the method of angular cor...
2007.06030v1
2021-06-17
Effects of Covid-19 Pandemic on Chinese Commodity Futures Markets
In this study, empirical moments and the cointegration for all the liquid commodity futures traded in the Chinese futures markets are analyzed for the periods before and after Covid-19, which is important for trading strategies such as pairs trading. The results show that the positive change in the average returns of t...
2106.09250v1
2021-06-28
Strap-on magnets: a framework for rapid prototyping of magnets and beam lines
We describe a framework to assemble permanent-magnet cubes in 3D-printed frames to construct dipole, quadrupole, and solenoid magnets, whose field, in the absence of iron, can be calculated analytically in three spatial dimensions. Rotating closely spaced dipoles and quadrupoles in opposite directions allows us to adju...
2106.14676v1
2021-07-08
Warm Magnets
Warm magnets are magnets that function in normal ambient temperature conditions. These types are mostly using a soft steel yoke for field amplification and either Copper or Aluminium coils or permanent magnets to generate the field. Magnets powered with such normal-conducting coils are often also called classical, iron...
2107.03965v1
2021-11-08
Thermogravimetric study of the non-stoichiometric wüstite FeOx. Pseudo phases w i and w' i . New T-P-X equilibrium phase diagram
A statistical numerical analysis of thermogravimetric measurements (temperature, mass variation, oxygen pressure) leads to a new equilibrium phase diagram T-P-X of the iron monoxide or w\"ustite FeOx. Three varieties or pseudo phases W1, W2, W3 are revealed above 911 {\textdegree}C, three others W'1, W'2, W'3 below. Th...
2111.04346v1
2017-04-19
Remote Document Encryption - encrypting data for e-passport holders
We show how any party can encrypt data for an e-passport holder such that only with physical possession of the e-passport decryption is possible. The same is possible for electronic identity cards and driver licenses. We also indicate possible applications. Dutch passports allow for 160 bit security, theoretically givi...
1704.05647v3
2017-05-02
Computation of the unifying thread in high temperature superconductors from first principles quantum Monte Carlo
It has long been a challenge to describe the origin of unconventional superconductivity. The two known examples with high Tc, based on iron and copper, have very different electronic structures, while other materials with similar electronic structure may not show superconductivity at all. In this paper, the authors sho...
1705.01008v1
2017-06-09
Ultrasound attenuation in $s^\pm$-wave two-band superconductors
The two-band $s^{\pm}$-wave state is currently considered to be the most promising candidate for newly discovered iron-based high-$T_c$ superconductors. In this work we study theoretically the ultrasound attenuation in $s^{\pm}$-wave two-band superconductors. The impurity effect is calculated within the $\mathcal{T}$-m...
1706.02963v1
2018-02-23
Electronic entropy in Green's-function calculations at finite temperatures
We revise critically existing approaches to evaluation of thermodynamic potentials within the Green's function calculations at finite electronic temperatures. We focus on the entropy and show that usual technical problems related to the multivalued nature of the complex logarithm can be overcome. This results in a simp...
1802.08495v1
2018-08-01
Long range dynamical coupling between magnetic adatoms mediated by a 2D topological insulator
We study the spin excitation spectra and the dynamical exchange coupling between iron adatoms on a Bi bilayer nanoribbon. We show that the topological character of the edge states is preserved in the presence of the magnetic adatoms. Nevertheless, they couple significantly to the edge spin currents, as witnessed by the...
1808.00347v1
2018-08-07
Origin of superconductivity in Ni-doped SrFe_2As_2 , an Insight from DMFT
I describe the issues of the competing orders in normal state of a parent and Ni-doped iron pnictide superconductor, SrF e 2 As 2 , using LMTO band structure calculation plus multi orbital dynamical mean-field theory. Strong, electronic correlations along with minimal antiferromagnetic instability create a partially ga...
1808.02298v1
2018-08-19
Size-dependent phase morphologies in LiFePO4 battery particles
Lithium iron phosphate (LiFePO$_4$) is the prototypical two-phase battery material, whose complex patterns of lithium ion intercalation provide a testing ground for theories of electrochemical thermodynamics. Using a depth-averaged (a-b plane) phase-field model of coherent phase separation driven by Faradaic reactions,...
1808.06164v1
2018-08-20
Production of Metal-free Diamond Nanoparticles
In this paper, the controlled production of high quality metal-free diamond nanoparticles is demonstrated. Milling with tempered steel is shown to leave behind iron oxide contamination which is difficult to remove. Milling with SiN alleviates this issue but generates more non diamond carbon. Thus the choice of milling ...
1808.06425v1
2018-10-14
Plasma opacity calculations using the Starrett and Saumon average-atom model with ion correlations
We present the opacities of iron, aluminum, and bromine plasmas calculated using the Starrett and Saumon average-atom model allowing for ion correlations. We show that the use of earlier average-atom ion-correlation model of Rozsnyai, as has recently been done in the solar opacity calculations, overestimates the effect...
1810.06027v1
2019-01-03
A magnetic tight-binding model : surface properties of transition metals and cobalt nanoparticules
The magnetic and surface properties of some transition metals have been investigated through the tight-binding approximation including Coulomb correlations. These surface properties are derived from a charge neutrality rule restricted to the d-band leading to a charge distribution including sp surface states in agreeme...
1901.00841v4
2019-01-28
X-ray diffraction analysis to support phase identification in FeSe and Fe$_7$Se$_8$ epitaxial thin films
X-ray diffraction (XRD) data and analysis for epitaxial iron selenide thin films grown by pulsed laser deposition (PLD) are presented. The films contain ${\beta}$-FeSe and Fe$_7$Se$_8$ phases in a double epitaxy configuration with the ${\beta}$-FeSe phase (001) oriented on the (001) MgO growth substrate. Fe$_7$Se$_8$ s...
1901.09794v1
2019-07-17
Role of interactions in the energy of the spin resonance peak in Fe-based superconductors
We consider the spin response within the five-orbital model for iron-based superconductors and study two cases: equal and unequal gaps in different bands. In the first case, the spin resonance peak in the superconducting state appears below the characteristic energy scale determined by the gap magnitude, $2\Delta_L$. I...
1907.08133v1
2019-10-07
Thermodynamic dislocation theory for polycrystals under tension/compression
Starting from the assumption that all possible orientations of grains are equally probable, we prove that the geometric factor of thermodynamic dislocation theory for polycrystals subjected to axially symmetric tension or compression must be equal to 2. We then use large-scale least-square analysis to identify the phys...
1910.02642v2
2019-10-25
Portable system for the prediction of anemia based on the ocular conjunctiva using Artificial Intelligence
Anemia is a major health burden worldwide. Examining the hemoglobin level of blood is an important way to achieve the diagnosis of anemia, but it requires blood drawing and a blood test. In this work we propose a non-invasive, fast, and cost-effective screening test for iron-deficiency anemia in Peruvian young children...
1910.12399v1
2020-03-04
Classical Nova Carinae 2018: Discovery of circumbinary iron and oxygen
We present time-lapse spectroscopy of a classical nova explosion commencing 9 days after discovery. These data reveal the appearance of a transient feature in Fe II and [O I]. We explore different models for this feature and conclude that it is best explained by a circumbinary disc shock-heated following the classical ...
2003.02008v1
2020-08-21
Multipole Orders in a Chain Ferrate Na2FeSe
Fundamental block and staggered orders of magnetic Fe multipoles in Na2FeSe2 are classified by their symmetry and magnetoelectric properties. Our structure model incorporates ferromagnetic or antiferromagnetic coupling between chains. The ferrate salt is valued in studies of highly correlated electrons as the only iron...
2008.09374v1
2020-09-07
Anomalous In-plane Magnetic Anisotropy in Strain-mediated Converse Magnetoelectric Coupling
Magnetic axis rotation (MAR) in ferromagnetic (FM) layers is crucial for strain-mediated converse magnetoelectric coupling. Employing the density functional theory (DFT), we computationally study the magnetic anisotropy of selected deformed FM materials such as body-centered iron. The results show that the short axis i...
2009.03045v2
2020-10-27
Thermodynamic approach to electric quadrupole moments
Higher-rank electric/magnetic multipole moments are attracting attention these days as candidate order parameters for exotic material phases. However, quantum-mechanical formulation of those multipole moments is still an ongoing issue. In this paper, we propose a thermodynamic definition of electric quadrupole moments ...
2010.13999v1
2020-11-18
Spin superfluidity in noncollinear antiferromagnets
We explore the spin superfluid transport in exchange interaction dominated three-sublattice antiferromagnets. The system in the long-wavelength regime is described by an $SO(3)$ invariant field theory. Additional corrections from Dzyaloshinskii-Moriya interactions or anisotropies can break the symmetry; however, the sy...
2011.09102v2
2020-12-22
Unusual Scaling of Kondo Spin Relaxation
The relation between the Kondo spin relaxation rate $ {\tau_{sK}}^{-1} $ and the Kondo momentum relaxation rate $ {\tau_{eK}}^{-1} $ is explored by using nonlocal spin valves with submicron copper channels that contain dilute iron impurities. A linear relation between $ {\tau_{sK}}^{-1} $ and $ {\tau_{eK}}^{-1} $ is es...
2012.11781v1
2020-12-23
Magnetic Moment Tensor Potentials for collinear spin-polarized materials reproduce different magnetic states of bcc Fe
We present the magnetic Moment Tensor Potentials (mMTPs), a class of machine-learning interatomic potentials, accurately reproducing both vibrational and magnetic degrees of freedom as provided, e.g., from first-principles calculations. The accuracy is achieved by a two-step minimization scheme that coarse-grains the a...
2012.12763v2
2021-03-08
All-order relativistic computations for atoms and molecules using an explicitly correlated Gaussian basis
A variational solution procedure is reported for the many-particle no-pair Dirac-Coulomb-Breit Hamiltonian aiming at a parts-per-billion (ppb) convergence of the atomic and molecular energies, described within the fixed nuclei approximation. The procedure is tested for nuclear charge numbers from $Z=1$ (hydrogen) to $2...
2103.04923v1
2021-03-14
Nuclear effects in neutrino-nucleus DIS and probe for short range correlation
We investigate charged-current neutrino-nucleus deep inelastic scattering with particular interests in relationship of short range correlation (SRC) and EMC effect. The structure functions $F^A_2(x,Q^2)$, $x F^A_3(x,Q^2)$ and ratios of differential cross sections are presented where the nuclei $A$ are chosen to be carb...
2103.07873v1
2021-04-05
Two-magnon Raman scattering in antiferromagnetic phases of frustrated spin models on the honeycomb lattice
We calculate the two-magnon Raman scattering spectra in antiferromagnetic phases of several frustrated spin models defined on the honeycomb lattice. These include the N\'{e}el antiferromagnetic phase of a $J_1$-$J_2$-$J_3$ model and the stripe phase of the Heisenberg-Kitaev model. We show that both the magnetic frustra...
2104.01903v1
2021-04-08
Ferromagnetism in a Semiconductor with Mobile Carriers via Low-Level Nonmagnetic Doping
We show that doped cubic iron pyrite, which is a diamagnetic semiconductor, becomes ferromagnetic when $p$-type doped. We furthermore find that this material can exhibit high spin polarization both for tunneling and transport devices. These results are based on first principles electronic structure and transport calcul...
2104.03877v1
2021-09-30
Pairing enhanced by local orbital fluctuations in a model for monolayer FeSe
The pairing mechanism in different classes of correlated materials, including iron based superconductors, is still under debate. For FeSe monolayers, uniform nematic fluctuations have been shown in a lattice Monte Carlo study to play a potentially important role. Here, using dynamical mean field theory calculations for...
2109.15312v1
2021-12-16
Investigating the Longitudinal Development of EAS with Ultra High Energies
The simulation of the extensive air showers was performed by investigating the longitudinal development parameters (N and Xmax) by using AIRES system version 19.04.0. The simulation was performed at the energy range (10^18-10^20 eV) for different primary particles (such as primary proton and iron nuclei) and different ...
2201.00401v1
2022-01-13
The FACET Project: Forward Aperture CMS ExTension to search for new Long-Lived Particles
FACET is a proposed new subsysem for CMS to search for portals such as dark photons, dark higgs, heavy neutral leptons and axion-like particles in the very forward direction at the High Luminosity LHC. Such particles can penetrate up to 50 m of iron and then decay inside a 14 m$^3$ vacuum pipe made by enlarging an 18 m...
2201.05224v1
2022-01-28
Theory of spin-excitation anisotropy in the nematic phase of FeSe obtained from RIXS measurements
Recent resonant inelastic x-ray scattering (RIXS) experiments have detected a significant high-energy spin-excitation anisotropy in the nematic phase of the enigmatic iron-based superconductor FeSe, whose origin remains controversial. We apply an itinerant model previously used to describe the spin-excitation anisotrop...
2201.12008v2
2022-04-28
Spin-glass-like behaviour in SmFeAsO0.8F0.2
The iron-based oxypnictide superconductor SmFeAsO0.8F0.2 was synthesized under high-pressure and investigated by measuring dc magnetic susceptibility. The zero-field cooled (ZFC) magnetic susceptibility confirmed the bulk superconductivity of the sample with a critical temperature of Tc = 50 K and a significant jump in...
2204.13473v2
2022-05-16
Feedback of non-local $d_{xy}$ nematicity on the magnetic anisotropy in FeSe
We analyze theoretically the magnetic anisotropy in the nematic phase of FeSe by computing the spin and the orbital susceptibilities from the microscopic multiorbital model. In particular, we take into account both the $xz/yz$ and the recently proposed non-local $xy$ nematic ordering and show that the latter one could ...
2205.07718v1
2022-08-05
Exploring the bouncing cosmological models in symmetric teleparallel gravity
In this study, cosmological models with perfect fluid and a gravitational framework f(Q) will be examined. In this modified theory of gravity, the gravitational force has the form f(Q), where Q stands for the non-metricity scalar. I create two bouncing cosmological models, one in which the Lagrangian f(Q) is assumed to...
2208.03171v1
2022-10-01
India Based Neutrino Observatory, Physics Reach and Status Report
The India-based Neutrino Observatory (INO) is a proposed underground facility located in India that will primarily house the magnetised Iron CALorimeter (ICAL) detector to study atmospheric neutrinos produced by interactions of cosmic rays with Earth's atmosphere. The physics goal is to to make precision measurements o...
2210.00206v2
2022-10-31
Superconducting Magnet System Concept with a Mechanical Energy Transfer in the Magnetic Field
There is an interest to design superconducting magnet systems working in a persistent current mode. These systems continuously generate magnetic field with disconnected power source working like permanent magnet devices. In this paper proposed a magnet system concept based on the direct mechanical energy transfer in th...
2211.00102v1
2022-10-31
HTS Dipole Magnet with a Mechanical Energy Transfer in the Magnetic Field
There were designed and successfully tested at Fermilab several high temperature superconducting (HTS) model magnets for particle accelerators. Some of them worked in a persistent current mode continuously generating magnetic field in the iron dominated magnet gap. In the paper was investigated a novel HT dipole magnet...
2211.00105v1
2022-11-02
A brief perspective of high temperature superconductivity in the cuprates: Strong correlations combined with superexchange match experiment
High temperature superconductivity encompasses the cuprates, nickelates, iron pnictides, and LaH$_x$ compounds. The first three groups of compounds involve in the pairing electrons, which are strongly to moderately correlated, whereas in the last class of systems specific phonon excitations. In this overview we concent...
2211.01024v1
2022-12-01
Numerical simulation of non-central collisions of spherical magnets
We present a computational model of non-central collisions of two spherical neodymium-iron-boron magnets, suggested as a demonstration of angular momentum conservation. Our program uses an attractive dipole-dipole force and a repulsive contact force to solve the Newtonian equations of motion for the magnets. We confirm...
2212.00876v1
2022-12-19
Equivalence of Active and Passive Gravitational Mass Tested with Lunar Laser Ranging
LLR measures the distance between observatories on Earth and retro-reflectors on Moon since 1969. In this paper, we study the possible violation of the equality of passive and active gravitational mass ($m_{a}/m_{p}$), for Aluminium (Al) and Iron (Fe), using LLR data. Our new limit of $3.9\cdot10^{-14}$ is about 100 ti...
2212.09407v1
2022-12-27
Tuning quantum paramagnetism and d-wave superconductivity in single-layer iron chalcogenides by chemical pressure
By substituting S into single-layer FeSe/SrTiO3, chemical pressure is applied to tune its paramagnetic state that is modeled as an incoherent superposition of spin-spiral states. The resulting electronic bands resemble an ordered checkerboard antiferromagnetic structure, consistent with angle-resolved photoemission spe...
2212.13603v2
2023-02-03
An Equilibrated Error Estimator for the 2D/1D MSFEM T-Formulation of the Eddy Current Problem
The 2D/1D multiscale finite element method (MSFEM) is an efficient way to simulate rotating machines in which each iron sheet is exposed to the same field. It allows the reduction of the three dimensional sheet to a two dimensional cross-section by resolving the dependence along the thickness of the sheet with a polyno...
2302.01601v1
2023-03-09
Full-waveform tomography reveals iron spin crossover in Earth lower mantle
Joint interpretation of bulk and shear wave speeds constrains the chemistry of the deep mantle. At all depths, the diversity of wave speeds cannot be explained by an isochemical mantle. Between 1000 and 2500 km depth, hypothetical mantle models containing an electronic spin crossover in (Mg,Fe)O provide a significantly...
2303.05476v1
2023-05-07
Surface supercurrent diode effect
We propose a new type of supercurrent diode effect on the surface of a superconductor with surface states under in-plane magnetic fields. Surface supercurrent diode effect can lead to a perfect supercurrent diode in a considerably wide range of fields. For comparison, the conventional supercurrent diode effect due to t...
2305.04219v2
2023-05-12
DFT+U Type Strong Correlation Functional Derived from Multiconfigurational Wavefunction Theory
We present a DFT+U-type functional for strong correlation, derived from multiconfigurational wavefunction theory. The reference system experiences electron-electron interactions only in DFT+U-type atomic states, yielding a block-localized configuration interaction Hamiltonian which depends on the atomic state occupanci...
2305.07736v2
2023-05-15
Easily Computed Marginal Likelihoods from Posterior Simulation Using the THAMES Estimator
We propose an easily computed estimator of marginal likelihoods from posterior simulation output, via reciprocal importance sampling, combining earlier proposals of DiCiccio et al (1997) and Robert and Wraith (2009). This involves only the unnormalized posterior densities from the sampled parameter values, and does not...
2305.08952v1
2023-08-01
Overview of superconductivity in field-cooled magnetic materials
Considerable experimental skills have been accumulated in the preparation of field-cooled (FC) magnetic materials. This stimulates the search for FC magnetic materials that are superconductors. The article overviews the recent proposed mechanism of superconductivity in field-cooled magnetic materials. It is based o...
2308.00470v1
2023-10-31
Generating site saturation mutagenesis libraries and transferring them to broad host range plasmids using type IIS restriction enzymes
Protein engineering is an established method for tailoring enzymatic reactivity. A commonly used method is directed evolution, where the mutagenesis and natural selection process is mimicked and accelerated in the laboratory. Here, we describe a reliable method for generating saturation mutagenesis libraries by golden ...
2311.00138v1
2023-11-21
Comment on "Ironing, sweeping, and multidimensional screening''
In their study of price discrimination for a monopolist selling heterogeneous products to consumers having private information about their own multidimensional types, Rochet and Chon\'e (1998) discovered a new form of screening in which consumers with intermediate types are bunched together into isochoice groups of var...
2311.13012v2
2024-01-04
Multiband Quantum Materials
Quantum materials are defined by the emergence of new properties resulting from collective quantum effects and by holding promise for their quantum applications. Novel superconductors, from high-Tc cuprates and iron-based superconductors to twisted monolayers, exhibit a higher level of emergent complexity, with a multi...
2401.02237v1
2024-01-07
Mid-infrared evidence for iron-rich dust in the multi-ringed inner disk of HD 144432
Context. Rocky planets form by the concentration of solid particles in the inner few au regions of planet-forming disks. Their chemical composition reflects the materials in the disk available in the solid phase at the time the planets were forming. Aims. We aim to constrain the structure and dust composition of the in...
2401.03437v1
2024-01-16
The effect of iron layer thickness on the interlayer exchange coupling in Fe/MgO (001) superlattices
We describe the effect of the Fe layer thickness on the antiferromagnetic interlayer exchange coupling in [Fe/MgO]$_N$ superlattices. An increase in coupling strength with increasing Fe layer thickness is observed, which highlights the need of including the extension of both the layers when discussing the interlayer ex...
2401.08336v1
2023-11-10
Automatic extraction and 3D reconstruction of split wire from point cloud data based on improved DPC algorithm
In order to solve the problem of point cloud data splitting improved by DPC algorithm, a research on automatic separation and 3D reconstruction of point cloud data split lines is proposed. First, the relative coordinates of each point in the cloud point are calculated. Second, it is planned to develop a relative ensemb...
2401.08587v1
2024-02-20
Electron-phonon coupling in ferromagnetic Fe-Co alloys from first principles
We calculate from first principles the electron-phonon coupling strength in ferromagnetic iron-cobalt Fe$_{1-x}$Co$_x$ alloys for compositions ranging from $x=0$ to $x=0.75$. We find strong, spin-dependent variation of the electron-phonon coupling strength with alloy composition. The minimum of the electron-phonon inte...
2402.12650v1
2024-02-20
Enhancement of the critical current by surface irregularities in Fe-based superconductors
The critical current $I_c$ of single crystals of the iron pnictide superconductor BaFe$_2$(As$_{1-x}$P$_x$)$_2$, has been studied through measurements of magnetic hysteresis cycles. We show that the introduction of surface irregularities in the $\mu$m scale significantly increase $I_c$, primarily near the irreversibili...
2402.12933v1
2024-03-28
X-ray reflectometric studies of nanoparticulate hematite films to decouple the rough and smooth behaviors of it and crystallographic and morphological properties concerning fatty acid chain length
In this study, the use of X-Ray reflectometry technique signifies the types of rough and smooth surfaces of hematite film prepared from different fatty acid derivatives of the iron salt. Followed by this, the film morphology and crystallographic properties concerning different fatty acid chain length have been discusse...
2403.19065v1
1995-06-14
ASCA PV observations of the Seyfert 1 galaxy MCG-6-30-15 : rapid variability of the warm absorber
We present a detailed re-analysis of the two {\it ASCA} Performance Verification observations of the nearby Seyfert 1 galaxy MCG-6-30-15. Confirming the results of Fabian et al. (1994), we find definite evidence for the {\sc O\,vii} and {\sc O\,viii} K-shell absorption edges of the warm absorber and a doubling of the w...
9506086v1
1996-03-18
The X-Ray Spectral Variability of Mrk 766
Analysis results from ASCA and ROSAT observations of the narrow-line Seyfert 1 galaxy Mrk 766 are reported. In the ASCA observation we observed rapid variability with a doubling time scale of 1000 seconds. A spectral variability event was observed in which the spectrum softened and hardened above and below ~1 keV, resp...
9603091v1
1996-04-23
The Luminosity-Metallicity Relation for Bulges of Spiral Galaxies
Optical integrated spectra of bulges have been obtained for 28 spiral galaxies. By applying an appropriate aperture size for each galaxy, the unavoidable contamination of disk starlight has been carefully minimized and set to $\sim$ 1/7 of the total stellar light. The sample covers a wide range in bulge luminosity and ...
9604132v1
1996-06-17
The variable iron K emission line in MCG-6-30-15
We report on the variability of the iron K emission line in the Seyfert 1 galaxy MCG--6-30-15 during a four-day ASCA observation. The line consists of a narrow core at an energy of about 6.4 keV, and a broad red wing extending to below 5 keV, which are interpreted as line emission arising from the inner parts of an acc...
9606103v1
1996-08-03
New beryllium observations in low-metallicity stars
We present observations of the Be II 313.0 nm resonance doublet in 14 halo and old disk stars with metallicities ranging from [Fe/H]=-0.4 to about -3.0 obtained with the CASPEC spectrograph of the ESO 3.6m telescope at a FWHM about 8.6 km/s resolution. Abundances are derived by means of the synthetic spectra technique ...
9608011v1
1996-09-15
Multiwavelength observations of isolated neutron stars as a tool to probe the properties of their surfaces
We show that an analysis of multiwavelength observations of isolated neutron stars based on neutron star atmosphere models can be used not only to evaluate the neutron star effective temperature, but also to determine chemical composition of its surface. To demonstrate how this new method can be applied to a specific o...
9609097v2
1996-10-16
An X-ray spectral study of 24 type-1 AGN
I present a study of the X-ray spectral properties of a sample containing 24 type-1 active galactic nuclei using the medium spectral resolution of ``ASCA''. The sample consists of 20 radio-quiet objects and 4 radio-loud objects. A simple power-law continuum absorbed by Galactic material provides a very poor description...
9610127v1
1996-12-10
An Investigation of Neutrino-Driven Convection and the Core Collapse Supernova Mechanism Using Multigroup Neutrino Transport
We investigate neutrino-driven convection in core collapse supernovae and its ramifications for the explosion mechanism. We begin with an ``optimistic'' 15 solar mass precollapse model, which is representative of the class of stars with compact iron cores. This model is evolved through core collapse and bounce in one d...
9612107v1
1997-01-08
A new chemo-evolutionary population synthesis model for early-type galaxies. II: Observations and Results
We present here the results of applying a new chemo-evolutionary stellar population model developed by ourselves in a previous paper (Vazdekis et al. 1996) to new high quality observational data of the nuclear regions of two representative elliptical galaxies and the bulge of the Sombrero galaxy. Here we fit in detail ...
9701036v1
1997-02-24
A New Approach to Determine the Initial Mass Function in the Solar Neighborhood
Oxygen to iron abundance ratios of metal-poor stars provide information on nucleosynthesis yields from massive stars which end in Type II supernova explosions. Using a standard model of chemical evolution of the Galaxy we have reproduced the solar neighborhood abundance data and estimated the oxygen and iron yields of ...
9702205v2
1997-07-15
Rotating Astrophysical Systems and a Gauge Theory Approach to Gravity
We discuss three applications of a gauge theory of gravity to rotating astrophysical systems. The theory employs gauge fields in a flat Minkowski background spacetime to describe gravitational interactions. The iron fluorescence line observed in AGN is discussed, assuming that the line originates from matter in an accr...
9707165v1
1997-10-28
Chemical abundances in the young galaxy at z=2.309 towards PHL 957
We present high-resolution UES spectra of the quasar PHL 957 obtained for studying the foreground Damped Ly-alpha galaxy at z=2.309. Measurements of absorption lines lead to accurate abundance determinations of Fe, S and N which complement measurements of Zn, Cr and Ni already available for this system. We find [Fe/H]=...
9710314v1
1997-12-02
Detecting Compton Reflection and a Broad Iron Line in MCG-5-23-16 with the Rossi X-ray Timing Explorer
We report the detection with the Rossi X-ray Timing Explorer of a Compton reflection signature in the Seyfert galaxy MCG-5-23-16. RXTE also resolves the Fe K-alpha fluorescence line with FWHM ~48,000 km s^{-1}. This measurement provides the first independent confirmation of ASCA detections in Seyfert galaxies of broad ...
9712035v2
1997-12-03
Resonance Averaged Photoionization Cross Sections for Astrophysical Models
We present ground state photoionization cross sections of atoms and ions averaged over resonance structures for photoionization modeling of astrophysical sources. The detailed cross sections calculated in the close-coupling approximation using the R-matrix method, with resonances delineated at thousands of energies, ar...
9712037v1
1997-12-25
Broadening of the Iron emission line in MCG-6-30-15 by Comptonization
We show that the Iron K emission line from MCG-6-30-15 could be broadened due to Comptonization by a surrounding highly ionized cloud with radius $\sim 10^{14}$ cms. We calculate the temperature of the cloud to be $\sim0.21\kev$, provided a reasonable estimate of the UV flux is made. The X-ray/$\gamma$-ray emission obs...
9712327v1
1998-02-11
The 6.4 keV Fluorescent Iron Line from Cluster Cooling Flows
For the inner region of the cooling flow (e.g. within the radius of $\sim$50--100 kpc) the Thomson optical depth of the hot gas in a massive cooling flow can be as large as $\sim 0.01$. Assuming that the cooling time in the inner region is few times shorter than the life time of the cluster, the Thomson depth of the ac...
9802130v1
1998-04-23
The broad-band X-ray spectrum of Mrk 3
We have used non-simultaneous Ginga, ASCA and ROSAT observations to investigate the complex X-ray spectrum of the Seyfert 2 galaxy Mrk 3. We find that the composite spectrum can be well described in terms of a heavily cut-off hard X-ray continuum, iron K_alpha emission and a soft X-ray excess, with spectral variability...
9804247v1
1998-05-05
Chemical composition and fundamental parameters of roAp stars
Element abundances of three roAp stars, HD 166473, HD 203932, and HD 217522, were determined using Kurucz model atmospheres with metal abundances scaled to solar ones and the results were compared with data from the literature concerning three further roAp stars, normal B and A stars and two lambda Bootis stars. Up to ...
9805037v1
1998-07-01
Magnetic Dipole Microwave Emission from Dust Grains
Thermal fluctuations in the magnetization of interstellar grains will produce magnetic dipole emission at frequencies below ~100 GHz. We show how to calculate absorption and emission from small particles composed of magnetic materials. The Kramers-Kronig relations for a dusty medium are generalized to include the possi...
9807009v1
1998-08-03
Cloud model of the mean quasar spectrum
We assume a distribution of clouds optically thick for electron scattering (OTCM) which are moderately optically thin for absorption and we consider them as a model of the mean quasar spectrum of Laor et al. (1997). We show that the model is particularly sensitive to the value of the ionization parameter $\xi$ and that...
9808014v1
1998-08-10
The Enrichment History of Hot Gas in Poor Galaxy Groups
We have analyzed the ASCA SIS and GIS data for seventeen groups and determined the average temperature and abundance of the hot x-ray emitting gas. For groups with gas temperatures less than 1.5 keV we find that the abundance is correlated with the gas temperature and luminosity. We have also determined the abundance o...
9808085v1