Inverse Structure Research Articles

Abstract 12856: Electrocardiographic T Wave Inversion and Cardiac Structure and Function

Background: Electrocardiographic T wave inversion (TWI) has been associated with incident heart failure (HF) in Black Americans without known coronary heart disease (CHD). The aim of this study was to investigate the relationship between TWI and left ventricular (LV) structure and function to evaluate cardiac changes that may precede symptomatic disease among Black Americans. Methods: Among 4134 Black American participants in the Jackson Heart Study without prevalent HF or CHD at baseline. We defined TWI as having negative T wave amplitudes in each lead of the 12-lead electrocardiogram. Outcomes of interest included echocardiographic LV structure (LV mass index, LVMI, LV diastolic dimension, LVDd and relative wall thickness, RWT) and LV function (LV ejection fraction, LVEF). We investigated the associations between TWI and LV structure and function using multiple linear regression analysis. For participants with missing values in any covariate of interest, values were imputed using multiple imputation by chained equations. Results: In this cohort with median age 55 years and 65% women. The depth of the inverted T wave in leads I and aVL were positively associated with RWT (Figure). The depth of the inverted T waves in leads II, III, and aVF were associated with LVDd. The depth of the inverted T waves in all the leads except V1 and V2 were associated with LVMI, while T wave inversions in only aVF were associated with LVEF. Conclusion: The depth of inverted T waves in leads I and aVL (which were associated with incident HF with preserved EF) were associated with LV concentricity while T wave amplitudes in leads II, III, and aVF (which were associated with incident HF reduced EF) were associated with LV eccentricity. Simple electrocardiographic information may be useful for identifying patients at risk of HF (stage B/pre HF).

Two-step exhumation of Caucasian intraplate rifts: A proxy of sequential plate-margin collisional orogenies

Intraplate structural deformation is diagnostic of tectonic stress regime changes linked to plate interactions and can result from superposed tectonic events whose single contributions are hardly distinguishable. In this paper, we present a set of integrated thermochronologic inverse models along a 140 km-long transect across the central Greater Caucasus and the adjacent Adjara-Trialeti fold-and-thrust belt of Georgia, two intraplate orogens produced by structural inversion of parallel continental rift zones located on the Eurasian plate. Our dataset allows to distinguish discrete and superposed deformation episodes and quantify their respective contributions to orogenic exhumation. The integration of (U-Th)/He analysis on apatite and zircon, fission-track analysis on apatite, and peak-temperature determinations (clay mineralogy, organic matter petrography, Raman spectroscopy) shows that structural inversion was punctuated by two incremental steps starting respectively in the latest Cretaceous and the mid-Miocene. Latest Cretaceous partial inversion of the Greater Caucasus is documented here for the first time and placed in a geographically wider context of coeval deformation. The two episodes of intraplate structural inversion, exhumation, and sediment generation are chronologically and physically correlated with docking of (i) the Anatolide-Tauride-Armenian terrane (Late Cretaceous - Paleocene) and (ii) Arabia (Miocene hard collision) against the southern Eurasian plate margin. Intraplate deformation in the Caucasian domain was triggered by far-field propagation of plate-margin collisional stress which focused preferentially along rheologically weak rift zones.

Morphology Engineering of the Asymmetric PS-b-P4VP Block Copolymer: From Porous to Nanodot Oxide Structures.

In the present work, we demonstrate the formation of oxide porous and nanodot structures from the same block copolymer (BCP) by the phase inversion of a BCP template. We investigated the effect of solvent annealing time on the ordering of asymmetric, cylinder forming, polystyrene-b-poly(4-vinylpyridine) (PS-b-P4VP) BCP. Phase separation of PS-b-P4VP was achieved by solvent vapor annealing (SVA) in a solvent atmosphere that is (partially) selective to P4VP to initially generate hexagonally arranged, cylindrical arrays of the expected structure. The morphology of the BCP changed from P4VP hexagonally packed cylinders to an 'inverse' structure with PS cylinders embedded in a P4VP matrix. This suggests that selective swelling occurs over time such that the swollen P4VP phase becomes the majority volume component. Metal ions (Ga3+, In3+) were infiltrated into the BCP templates by a solution-mediated infiltration approach, followed by an ultraviolet-ozone treatment to remove the polymer and oxidize the metallic ions to their oxides. The findings show that a single BCP can be used to create both metal oxide arrays and porous structures of metal oxides by simply varying the duration of the solvent annealing process. The resulting structures were analyzed through several methods including scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy, and energy-dispersive X-ray spectroscopy. XPS analyses confirmed the complete elimination of the BCP template and the presence of metal oxides. This study provides important insights into the development of functional BCP materials with inverse structures.

Structural and optical integrity of pure and NiFe2O4-GO nanoferrite: A combined experimental and first principles approach

Graphene oxide (GO)-supported nickel ferrite (NiFe2O4) nanoparticles were prepared via the chemical co-precipitation technique. The resulting pure NiFe2O4 and NiFe2O4/GO nanocomposites display an inverse cubic spinel structure with binary interstice occupancy according to experimental and density functional theory (DFT) simulations. The structural-dependent physiochemical variations reflect in the narrow bandgap of GO-coupled NiFe2O4 with a distinct structural landscape. The narrow optical bandgap of the resultant GO-NiFe2O4 (1.48 eV) nanoferrite illustrates their potential utility as a promising photocatalyst with active charge separation.

Inverse design of electromagnetically induced transparency metamaterials based on generative adversarial networks

The traditional metamaterial design process usually relies on some knowledge experience and simulation tools to continuously optimize by trial and error, until the simulation results meet the requirements. But this trial-and-error approach could be more unstable and time-consuming, especially when there are too many material parameters or the optimization interval is too large. This paper proposes a multi-prediction model for metamaterials, Improved-StarGan based on StarGan with semi-supervised learning, and use an EIT structure as a validation object. The generator can output various material structures according to the input spectrum extremes, and the discriminator can forward predict the spectrum extremes based on the input material structure parameters. Spectral normalization, gradient penalty, and hidden space distance regularization are also used to increase the diversity of its output data at the expense of sacrificing a part of the accuracy of the generator. During model training, the loss values of the training and validation sets converge normally and end up in a small range. Finally, the data was extracted from the test set for model prediction and simulation comparison. Meanwhile, a sample of one of the predicted structures is tested. All the results show that the model predictions have low error and high confidence. the results demonstrate that the method is effective in both inverse multiple structure and forward prediction of metamaterials, which provides a new design idea for the structural design of metamaterials.

Magnetic properties and identification of Griffiths-like phase in Mn2FeSi Heusler antiferromagnet

Materials having low magnetic moments with high spin polarization are promising for spintronic applications. Among these materials, Mn-based Heusler alloys are attractive candidates due to the antiferromagnetic alignment of Mn atoms. Theoretical calculations predict Mn2FeSi to have an inverse Heusler (XA) structure with a magnetic moment of 2 μB/f.u. However, no experimental reports exist on a phase-pure composition of this material. In this study, our first principle calculations demonstrate the effect of various types of disorder on the electronic and magnetic properties of Mn2FeSi. The B2-type disorder seems responsible for forming secondary phases in stoichiometric Mn2FeSi. We verify this by conducting theoretical calculations for different configurations of the atomic disorders permissible in a Heusler phase. We substantiate our theoretical investigation with an experimental study wherein we first stabilize the phase-pure Mn2FeSi in an inverse Heusler structure by substituting Al at the Si site. Amongst the prepared Mn2FeSi1−xAlx (x = 0, 0.1, 0.15), the compositions with x = 0 and 0.15 show a clear presence of a secondary phase, identified as the β − Mn phase with a lattice constant of 6.24 Å. Analysis of the back-scattered electron spectroscopy images and X-ray diffraction patterns confirm the formation of a pure Heusler phase in x = 0.1 composition. Magnetization measurements reveal an antiferromagnetic behavior in all compositions, with a N é el temperature of ∼ 50 K. However, deviation from Curie-Weiss law was observed for x = 0.1, suggesting competing magnetic interactions. Further investigation into the magnetic properties of this composition displays signatures of Griffiths phase, possibly caused by antisite disorder in the compound.

Psych verbs: the behavior of ObjExp verbs in Brazilian Portuguese

Abstract Psychological verbs, especially Object Experiencer verbs, are widely discussed in the linguistic literature because of their peculiar syntactic and semantic properties. Two main issues regarding Object-Experiencer verbs are often raised: their aspectual nature and an alternation process (with the experiencer in subject position). This article analyzes Brazilian Portuguese Object Experiencer verbs, focusing on these issues. Based on a study of 170 verbs, we claim that Object Experiencer verbs constitute a verb class whose members describe a complex stage-level state in which a stimulus state activates (in a causative relation) a mental state in an experiencer. In addition, we argue that Object-Experiencer verbs appear in an inverse form: the experiencer as subject, and the stimulus as oblique. We claim that such an inverse form does not result from the causative alternation. In the inverse structure, different from an inchoative form of a change-of-state verb, both arguments are strongly preferable, and the verbs still denote a stative situation. We also provide a representation for the event structure of those verbs, using predicate decomposition, that is associated with their syntactic properties.

The acoustic size of the Sun

ABSTRACT Analysis of f-mode frequencies has provided a measure of the radius of the Sun which is lower, by a few hundredths per cent, than the photospheric radius determined by direct optical measurement. Part of this difference can be understood by recognizing that it is primarily the variation of density well beneath the photosphere of the star that determines the structure of these essentially adiabatic oscillation modes, not some aspect of radiative intensity. In this paper we attempt to shed further light on the matter, by considering a differently defined, and dynamically more robust, seismic radius, namely one determined from p-mode frequencies. This radius is calibrated by the distance from the centre of the Sun to the position in the subphotospheric layers where the first derivative of the density scale height changes essentially discontinuously. We find that radius is more-or-less consistent with what is suggested by the f modes. In addition, the interpretation of the radius inferred from p modes leads us to understand more deeply the role of the total mass constraint in the structure inversions. This enables us to reinterpret the sound-speed inversion, suggesting that the positions of the photosphere and the adiabatically stratified layers in the convective envelope differ non-homologously from those of the standard solar model.

Assessment of vertical characterization and potential sources of aerosols in different altitude layers: Combined application of MAX-DOAS observation and the 3D-CWT model

Vertical distribution is essential for understanding the regional transport sources of pollutants accumulated at different altitudes. We investigate aerosol extinction coefficient (AEC) profiles based on ground-based multi-Axis differential optical absorption spectroscopy measurements from August 2020 to June 2021 in Ningbo, East China. AEC vertical structures can be classified into three groups: decreasing with height (51.2%), well-mixed (2.4%), and inverse structures (46.4%), which can be explained by long-range transport, the planetary boundary layer heigh, and temperature inversion. Except in the winter, the vertical profile of the AEC typically extends to higher altitudes, which suggests the accumulation, secondary formation, or long-range transport of aerosols at higher altitudes. The three-dimensional concentration weighted trajectory (3D-CWT) model is utilized to elucidate not only altitudinal atmospheric layers in which aerosol transport occurs, but also the potential source areas of aerosols at multiple air mass arrival altitudes. The 3D-CWT model results indicate the long-range transport of aerosols, mainly through backward air mass trajectories within layers 1 (0–500 m) and 2 (500–1000 m). The potential source areas of aerosols at lower altitudes are mainly distributed in the North China Plain. At air mass arrival altitudes exceeding 600 m, the sources likely to affect aerosols in Ningbo are both land-sourced and marine-sourced (including the East China Sea, Yellow Sea, and the marginal sea between Korea and Japan) air flows. At different air mass arrival altitudes, the estimated contributions of long-range transport to aerosols are approximately 6% (200 m), 11% (600 m), and 18% (1000 m). Our findings provide a scientific basis for revealing different aerosol vertical structures and assessing long-range transport contributions in coastal urban areas.

Radar Emitter Structure Inversion Method Based on Metric and Deep Learning

With the rapid development of modern military countermeasure technology, deep distinguish hostile radar is essential in electronic warfare. However, traditional radio frequency (RF) feature extraction methods can easily be interfered by signal information and fail due to the lack of research on RF feature extraction techniques for complex situations. Therefore, in this paper, first, the generation mechanism of RF structure information is discussed, and the influence of different signal information introduced by different operating parameters on RF structure feature extraction is analyzed. Then, an autoencoder (AE) network and an autoencoder metric (AEM) network are designed, introducing metric learning ideas, so that the extracted deep RF structure features have good stability and divisibility. Finally, radar emitter structure (RES) inversion is realized using the centroid-matching method. The experimental results demonstrate that this method exhibits good inversion performance under variable operating parameters (modulation type, frequency, bandwidth, input power). RES inversion including unknown operating parameters is realized for the first time, and it is shown that metric learning has the advantage of separability of RF feature extraction, which can provide an idea in emitter and RF feature extraction.

The effects of uplift and erosion on the petroleum systems in the southwestern Barents Sea: Insights from seismic data and 2D petroleum systems modelling

In the past three decades, the hydrocarbon prospectivity has been enigmatic in the southwestern Barents Sea as gas discoveries have dominated over oil. However, more recent discoveries indicate oil potential, especially in the Polheim Platform and Hoop Complex areas. Cenozoic uplift and erosion episodes are critical because they control the duration and depth of maximum burial of source rocks and the reduction of porosity of reservoir rocks due to diagenetic processes at larger depth and increased temperatures. Modelling of interpreted horizons from the southwestern Barents Sea provide a best-fit realization of the basin-scale sedimentary filling from the post-rifting in the Jurassic until the Last Glacial Maximum. 2D basin modelling was performed across one regional seismic section crossing the southwestern Barents Sea. For calibration of the 2D model, 1D modelling was performed for a selected number of wells in the region by integrating different estimates of net apparent erosion (velocity inversion of wells, interpreted profiles and structure maps as well as from temperature and vitrinite reflectance data) in order to assess the burial, thermal and maturity history of the source rocks at various well locations as well as along the 2D profile. Simulation results show that the Upper Jurassic source rock is immature to marginal mature in the central and eastern parts of the Norwegian Barents Sea. The western part is characterised by high chargeability of traps associated with rich source kitchens and porous reservoir rocks. Although not proven by commercial discoveries, there are evidences that the Permian Ørret and the Lower-Middle Triassic basal Klappmyss and basal Kobbe shales may be important gas-prone source rocks in the eastern Norwegian Barents Sea. Consequently, the exploration must rely on the Triassic and/or Palaeozoic source rocks in the eastern area.

Valley-dependent topological phase transition in monolayer ferrovalley materials RuXY (X, Y = F, Cl, Br)

Due to the breaking of the time reversal symmetry and spatial inversion symmetry, hexagonal ferrovalley materials have intrinsic large valley polarization. Model analysis shows that tuning the two different band gaps of valleys can realize phase transitions between ferrovalley semiconductors, half valley metals, and valley-polarized quantum anomalous Hall semiconductors. Through first-principle calculations, monolayer ferrovalley materials RuXY (X, Y = F, Cl, Br), which exhibit valley splitting at the top valence band and the bottom conduction band, are predicted to achieve this valley-dependent topological phase transition. Due to the different orbital proportions of d orbitals, the valley splitting at the top valence band is much greater than that at the bottom conduction band. Strain can regulate the interaction between orbitals, thus producing valley-dependent band inversion, leading to the quantum spin or valley Hall effect. The chiral edge states are demonstrated under appropriate biaxial strain. The topological phase transition is related to the inversion of the band structure and Berry curvatures at K and K′ valleys. These results have certain significance for the design of two-dimensional valley-dependent quantum materials and the application of valleytronic devices.

Magneto-optical transport of thin film topological insulators with structure inversion asymmetry

Magneto-optical transport of thin film topological insulators with structure inversion asymmetry

Dominant Cloud Controlling Factors for Low‐Level Cloud Fraction: Subtropical Versus Extratropical Oceans

AbstractTo improve cloud feedback understanding and simulation, observations have been used to quantify the rate of change of cloud radiative properties as a function of specific environmental metrics (or cloud controlling factors; CCFs). The study focuses on low‐level cloud dominated regions during 2006–2010. For each ocean gridpoint, Spearman's rank correlation coefficients of daily mean observed cloud fraction versus (a) 10‐m wind, (b) sensible heat flux (SHF), (c) sea surface temperature, (d) estimated inversion strength (EIS), (e) 850 hPa vertical velocity, and (f) the M parameter () are sorted to identify the dominant CCFs in both extratropics (30°–60°N/S) and subtropics (30°S–30°N). A novel map for visualizing dominant CCFs for low‐level cloud fraction reveals that: dominates in the subtropical stratocumulus regions while 10‐m winds dominate in shallow cumulus regions but in the extratropics, a different inversion structure diagnostic (EIS) dominates, while SHF dominates in western boundary current areas.

Nondegenerate Integer Quantum Hall Effect from Topological Surface States in Ag2Te Nanoplates.

The quantum Hall effect is one of the exclusive properties displayed by Dirac Fermions in topological insulators, which propagates along the chiral edge state and gives rise to quantized electron transport. However, the quantum Hall effect formed by the nondegenerate Dirac surface states has been elusive so far. Here, we demonstrate the nondegenerate integer quantum Hall effect from the topological surface states in three-dimensional (3D) topological insulator β-Ag2Te nanostructures. Surface-state dominant conductance renders quantum Hall conductance plateaus with a step of e2/h, along with typical thermopower behaviors of two-dimensional (2D) massless Dirac electrons. The 2D nature of the topological surface states is proven by the electrical and thermal transport responses under tilted magnetic fields. Moreover, the degeneracy of the surface states is removed by structure inversion asymmetry (SIA). The evidenced SIA-induced nondegenerate integer quantum Hall effect in low-symmetry β-Ag2Te has implications for both fundamental study and the realization of topological magneto-electric effects.

Ferroelectric polarization tailored spin polarized electronic structure and magnetic anisotropy in two-dimensional ScSi2N4/CuInP2S6 multiferroic heterostructures

Two-dimensional (2D) van der Waals (vdW) multiferroic heterostructures which consist of vdW intrinsic magnets and ferroelectrics (FEs) plays an extremely important role in novel 2D spintronic devices. In this paper, the electronic structure and magnetic anisotropy of 2D vdW ScSi2N4/CuInP2S6 heterostructure are systematically investigated using first-principles calculation. CuInP2S6 is a 2D FE material with out-of-plane polarization, and ScSi2N4 is a half-metal with ferromagnetic (FM) properties. After the ab initio molecular dynamics simulations, the structures of upward polarization (P↑) and downward polarization (P↓) states are stable. Both the P↑ and P↓ states of ScSi2N4/CuInP2S6 heterostructure are FM half-metals. Biaxial strains modulate the electronic structure and magnetic properties of the ScSi2N4/CuInP2S6 heterostructure. With the application of compressive strains in P↓ state, the spin-up band crosses Fermi level and the P↓ state changes from half-metal to metal. The transition from half-metal to metal in P↑ state is realized at ϵ = −4% and ϵ = −6%. The magnetic anisotropy energy of the P↓ state can be enhanced by compressive strains of −2% and −4%. The P↓ state shows the largest average planar electrostatic potential of 0.819 eV at ϵ = −6%, which keeps the maximum electrostatic field between ScSi2N4 and CuInP2S6 monolayers. As the strain increases from −2% to −6%, the potential difference of P↑ state increases gradually. At +6% tensile strain, the band structure inversion occurred in both P↑ and P↓ states. These results demonstrate the potential of 2D vdW multiferroic heterostructures and can enrich the field of spintronic devices.

On the possibility of low-symmetry structures in Zr2CoSi

First principles calculation shows that the energy difference between the cubic L21 and Hg2CuTi inverse structure for Zr2CoSi is 1.454 eV/f.u., indicating than the L21 structure is more stable. The density of states and band structure of Zr2CoSi in the L21 structure do not support the half–metallic state. Moreover, van Hove singularity involving partially occupied Co 3d eg states occurs in minority states at the Fermi level and the Zr2CoSi in L21 structure satisfies the preconditions to exhibit a cubic-to-tetragonal instability according to a band-Jahn-Teller mechanism. The computed total energy landscapes of the system shows that there are two tetragonal and one orthorhombic distorted phases of Zr2CoSi that are energetically favored over the undistorted cubic L21 structure. However, only one tetragonal phase of Zr2CoSi with c/a > 1.0 fulfills necessary and sufficient elastic stability conditions for both GGA and LDA exchange–correlation potentials.

Large-band-gap non-Dirac quantum spin Hall states and strong Rashba effect in functionalized thallene films

The quantum spin Hall state materials have recently attracted much attention owing to their potential applications in the design of spintronic devices. Based on density functional theory calculations and crystal field theory, we study electronic structures and topological properties of functionalized thallene films. Two different hydrogenation styles (Tl2H and Tl2H2) are considered, which can drastically vary the electronic and topological behaviors of the thallene. Due to the C3v symmetry of the two systems, the px and py orbitals at the Γ point have the non-Dirac band degeneracy. With spin–orbit coupling (SOC), topological nontrivial band gaps can be generated, giving rise to non-Dirac quantum spin Hall states in the two thallium hydride films. The nontrivial band gap for the monolayer Tl2H is very large (855 meV) due to the large on-site SOC of Tl px and py orbitals. The band gap in Tl2H2 is, however, small due to the band inversion between the Tl px/y and pz orbitals. It is worth noting that both the Tl2H and Tl2H2 monolayers exhibit strong Rashba spin splitting effects, especially for the monolayer Tl2H2 (αR = 2.52 eVÅ), rationalized well by the breaking of the structural inversion symmetry. The Rashba effect can be tuned sensitively by applying biaxial strain and external electric fields. Our findings provide an ideal platform for fabricating room-temperature spintronic and topological electronic devices.

Mössbauer analysis, structural parameter studies and magnetic properties of LiCoxFe5-xO8 (x= 0, 0.025, 0.05, 0.075, 0.1) nanoparticles

We report on detailed structural parameter analysis, Mössbauer spectra and magnetic properties of LiCoxFe5-xO8 (x = 0, 0.025, 0.05, 0.075, 0.1) nanoparticles prepared by sol-gel method. Prepared LiCoxFe5-xO8 nanoparticles crystalizes in inverse spinel structure with the crystallite size ranging from 23.7 to 29.8 nm. Hopping length, radii of tetrahedral and octahedral sites (rA and rB), tetrahedral bond length (dAx), octahedral bond lengths (dBx), tetrahedral and octahedral shared edges (dAxE, dBxE), unshared octahedral edges (dBxEU) values and oxygen positional parameter (u) are seen to increase with increasing Co concentration. Chemical state of all the elements are confirmed by X-ray photoelectron spectroscopy technique. The hyperfine field, isomer shift, quadrupole shift and line width parameters calculated from the Mössbauer spectra confirms the Co2+ substitution in LiFe5O8. The saturation magnetization value decreases from 59.2 to 54.1 emu/g with increasing Co concentration, which is examined by three sublattice model derived by Yafet and Kittel (Y-K model). Y-K angles increases with Co concentration from 16.46 to 19.98°. Curie temperature of LiFe5O8 decreases from 865 K to 858 K with increasing Co concentration to x = 0.1.

Au@Fe3O4 NANOPARTICLES: PREPARATION, CHARACTERIZATION AND CYTOTOXIC EVALUATION

Gold-coated iron oxide nanoparticles are a class of potential theranostic nanoparticles that have been studied for their multitude of magnetic and optical properties with possible medical applications. In this work, spherical Au@Fe3O4 nanoparticles were successfully synthesized from Fe electrodes immersed in HAuCl4 solution using a very simple method - pulsed plasma in liquid, without any dopants or special conditions for stabilization. Vibrating sample magnetometer indicated ferromagnetic behavior of the particles at room temperature with coercivity and saturation magnetization of Hc=175 and Ms= 3.56 emu/g, respectively. Face-centered cubic Au and spinel inverse structure of FCC- Fe3O4 were determined by X-Ray diffraction analysis. High-resolution transmission electron microscopic analysis revealed that Fe3O4 particles with 14 nm in size are connected to 18 nm Au particles. The cytotoxicity of the nanoparticles was evaluated using a XTT assay on Hela cells, revealing very low (cell viability: 98-89% with Fe3O4 and 99-91% for Au@Fe3O4 NPs). This indicates that Au improves biocompatibility of magnetic nanoparticles, enabling their application in biomedicine