Strong Interference Effects Research Articles

Multi-component quantitative analysis of LIBS using adaptively optimized multi-branch CNN

Multi-component quantitative analysis of laser-induced breakdown spectroscopy (LIBS) is very important for industrial process control, food safety and space exploration. Due to the strong background interference and complex matrix effect, traditional quantitative analysis methods are difficult to realize accurate multi-component regression. Deep learning has the advantages of automatically extracting full-spectrum features and strong nonlinear modeling capabilities, which provides new opportunities for advancing the progress of LIBS quantitative analysis. However, due to the large difference of spectral line intensity and spectral cross-interference, existing deep learning models have limited performance for simultaneous multi-component regression. To this end, a novel adaptively optimized multi-branch convolution neural network (AOMB-CNN) framework is proposed for multi-component quantitative analysis of LIBS. Multi-branch structure is adopted to ensure the accuracy of multi-component content simultaneously. Dynamic weighted loss function and Bayesian optimization algorithm are used to adaptively optimize the deep learning model. The results demonstrate that the AOMB-CNN can effectively improve the performance of multi-component regression on 2 LIBS datasets compared with the traditional quantitative analysis methods. The root mean square error (RMSE) of 8 components of the ChemCam test set are 2.4465, 0.3486, 1.2481, 1.3909, 0.9010, 0.8892, 0.6700, and 0.5498 respectively, and the RMSE of 4 components of the steel test sets are 1.9787, 0.3455, 0.6025 and 1.6631 respectively. The proposed method provides an end-to-end, adaptively optimized, full-spectrum deep learning solution for LIBS multi-component content measurement without human intervention.

Aerodynamic interaction characteristics analysis of intermeshing-rotor fuselage in hover

Abstract To study the interference characteristics of the intermeshing-rotor fuselage, a numerical simulation method for the flow field of a crossed twin-rotor helicopter in a hovering state is established based on the lattice Boltzmann method. The effectiveness of the proposed numerical simulation method is first verified by the ROBIN helicopter rotor/fuselage interference example. Then, taking the simplified JZ-60 rotor and S-97 helicopter fuselage as the research objects, the aerodynamic interference characteristics of the intermeshing rotor and the fuselage are investigated, and the aerodynamic interference law between the two under the hovering state is obtained. The results show that the intermeshing rotor has periodic tension fluctuation, and the fuselage interference leads to about a 4% increase in the total tension of the rotor. The maximum hovering efficiency increases by about 5%, and the larger the tension coefficient is, the larger the fuselage gains on the hovering efficiency is. The fuselage generates periodic negative lift and lateral force under the influence of the rotor. The hovering efficiency gains of the rotor mainly originate from the increases of the blade lift coefficients in the vicinity of the azimuth angles of 0° and 180°. The rotor is in the range of 0.5° and 180°, which has the strongest interference effect on the fuselage near 0.6 R and -0.7 R.

Is processing superiority a universal trait for all threats? Divergent impacts of fearful, angry, and disgusted faces on attentional capture

Fearful, angry, and disgusted facial expressions are evolutionarily salient and convey different types of threat signals. However, it remains unclear whether these three expressions impact sensory perception and attention in the same way. The present ERP study investigated the temporal dynamics underlying the processing of different types of threatening faces and the impact of attentional resources employed during a perceptual load task. Participants were asked to judge the length of bars superimposed over faces presented in the center of the screen. A mass univariate statistical approach was used to analyze the EEG data. Behaviorally, task accuracy was significantly reduced following exposure to fearful faces relative to neutral distractors, independent of perceptual load. The ERP results revealed that the P1 amplitude over the right hemisphere was found to be enhanced for fearful relative to disgusted faces, reflecting the rapid and coarse detection of fearful cues. The N170 responses elicited by fearful, angry, and disgusted faces were larger than those elicited by neutral faces, suggesting the largely automatic and preferential processing of threats. Furthermore, the early posterior negativity (EPN) component yielded increased responses to fearful and angry faces, indicating prioritized attention to stimuli representing acute threats. Additionally, perceptual load exerted a pronounced influence on the EPN and late positive potential (LPP), with larger responses observed in the low perceptual load condition, indicating goal-directed cognitive processing. Overall, the early sensory processing of fearful, angry, and disgusted faces is characterized by differential sensitivity in capturing attention automatically, despite the importance of these facial signals for survival. Fearful faces produce a strong interference effect and are processed with higher priority than angry and disgusted ones.

Optical-Cavity-Incorporated Colorful All-Solid-State Electrochromic Devices for Dual Anti-Counterfeiting.

The fusion of electrochromic technology with optical resonant cavities presents an intriguing innovation in the electrochromic field. However, this fusion is mainly achieved in liquid electrolyte-based or sol-gel electrolyte-based electrochromic devices, but not in all-solid-state electrochromic devices, which have broader industrial applications. Here, a new all-solid-state electrochromic device is demonstrated with a metal-dielectric-metal (MDM) resonant cavity, which can achieve strong thin-film interference effects through resonance, enabling the device to achieve unique structural colors that have rarely appeared in reported all-solid-state electrochromic devices, such as yellow green, purple, and light red. The color gamut of the device can be further expanded due to the adjustable optical constants of the electrochromic layer. What is more, this device exhibits remarkable cycling stability (maintaining 84% modulation capability after 7200 cycles), rapid switching time (coloration in 2.6 s and bleaching in 2.8 s), and excellent optical memory effect (only increasing by 13.8% after almost 36 000 s). In addition, this exquisite structural design has dual-responsive anti-counterfeiting effects based on voltage and angle, further demonstrating the powerful color modulation capability of this device.

Nature of anomalous electrical resistance in Co73-xFe4CrxSi12B11 amorphous microwires

Influence of structural relaxation and composition of microwires of metallic amorphous alloys Co73-xFe4CrxSi12B11 (x = 0, 2, 4, 6, 8) on the character and mechanisms of temperature dependence of electrical resistance r(T) has been studied in a wide temperature range (from 4.2 K to crystallization temperature). It is shown that alloys with more than 2 at.% Cr have a number of specific properties, which are significantly differentiate them from Fe- and Ni-rich alloys, as well as many Co-rich amorphous alloys. The features of Cr-doped Co-rich alloys are explained by two reasons: firstly, very strong quantum interference effects of the electron-electron interaction and weak localization of electrons caused by scattering of electrons by the potential created by randomly distributed chromium atoms, and secondly, partially reversible compositional structural relaxation leading to clustering of the amorphous phase at T > 300 °C. It is assumed that the resulting Cr-rich clusters, in which chromium atoms are bonded to metalloid atoms, can enhance these interference effects. The contributions from various mechanisms of interaction and scattering of electrons to the change in electrical resistance with temperature and composition of the alloy are analyzed. The fitting parameters for them are determined and compared with the known data.

Enhanced Broadband Light Harvesting in Ultrathin Absorbers Enabled by Epitaxial Stabilization of Silver Thin Film Mirrors.

Silver thin film mirrors are attractive candidates for use as specular back reflectors to enhance broadband light absorption via strong optical interference in ultrathin film semiconductor photoabsorbers. However, deposition of metal-oxide absorbers often requires exposure to high temperature in an oxygen atmosphere, conditions that cause thermal etching and degrade the specular reflectance of silver films. Here, we overcome this challenge and demonstrate that epitaxial growth of silver mitigates thermal etching under the high-temperature oxygen-containing environments that cause polycrystalline films to degrade. The degree of thermal etching resistance is related to the epitaxial film structure, where high-quality films completely prevent thermal etching, allowing for direct deposition of metal-oxide thin film photoabsorbers at elevated temperatures without any degradation of the optical properties of the silver layer. As a proof of concept for device applications, a metal-oxide photoanode for photoelectrochemical water splitting is fabricated by directly growing epitaxial SnO2 and Ti-doped α-Fe2O3 (hematite) thin films onto stabilized silver reflectors by pulsed laser deposition. The photoanode displays enhanced broadband light absorption due to strong interference effects enabled by the highly reflective silver film and demonstrates stable operation in a photoelectrochemical cell under conditions of water photo-oxidation in alkaline electrolyte.

Propagation of synchrotron radiation through double microchannel plate device: Comparison of experimental data and wave-approach simulation

Since third-generation synchrotron radiation facilities are highly brilliant sources, the scattering of a partially coherent beam gives rise to strong interference effects. We present and discuss in this contribution the comparison of simulated and experimental diffraction patterns collected with an optical device made by two identical flat Micro Channel Plates (MCPs) illuminated by synchrotron radiation at different energies. The experimental patterns clearly show the increase of the density of the main peak with respect to those collected with a single flat MCP. Data demonstrate that the use of a device based on two MCPs is an ideal optical system to condense the primary radiation in a narrow intense central peak.

Study on the Biomolecular Competitive Mechanism of Polybrominated Diphenyl Ethers and Their Derivatives on Thyroid Hormones.

Polybrominated diphenyl ethers (PBDEs) are widely used brominated flame retardants. PBDEs and their derivatives, hydroxylated PBDEs (OH-PBDEs), can bind to hormone receptors and impact hormone secretion, transportation, and metabolism, leading to endocrine disruption and the development of various diseases. They have particularly strong interference effects on thyroid hormones. This study used decabromodiphenyl ether (BDE-209); 2,2',4,4'-tetrabromodiphenyl ether (BDE-47); and 6-OH-BDE-47 as representative compounds of PBDEs and their derivatives, OH-PBDEs. A fluorescence probe, fluorescein-isothiocyanate-L-thyroxine (FITC-T4, F-T4), specific for binding to transthyretin (TTR), a thyroid transport protein, was prepared. The binding capacity of PBDEs and their derivatives, OH-PBDEs, to TTR was quantitatively measured using fluorescence spectroscopy. The principle of quenching the fluorescence intensity of F-T4 after binding to TTR was used to analyze the competitive interaction between the probe and BDE-209, BDE-47, and 6-OH-BDE-47, thereby evaluating the toxic effects of PBDEs and their derivatives on the thyroid system. Additionally, AutoDock molecular docking software (1.5.6) was used to further analyze the interference mechanism of OH-PBDEs on T4. The results of the study are as follows: (1) Different types of PBDEs and OH-PBDEs exhibit varying degrees of interference with T4. Both the degree of bromination and hydroxylation affect their ability to competitively bind to TTR. Higher bromination and hydroxylation degrees result in stronger competitive substitution. (2) The competitive substitution ability of the same disruptor varies at different concentrations. Higher concentrations lead to stronger substitution ability, but there is a threshold beyond which the substitution ability no longer increases. (3) When OH-PBDEs have four or more bromine atoms and exhibit the most structural similarity to T4, their binding affinity to TTR is stronger than that of T4.

Angle-Insensitive Ultrathin Broadband Visible Absorber Based on Dielectric-Semiconductor-Lossy Metal Film Stacks.

Ultrathin broadband absorbers with high efficiency, wide angular tolerance, and low fabrication cost are in demand for various applications. Here, we present an angle-insensitive ultrathin (<150 nm) broadband absorber with an average 96.88% (experiment) absorptivity in the whole visible range by utilizing a simple dielectric-semiconductor-lossy metal triple-layer film structure. The excellent broadband absorption performance of the device results from the combined action of the enhanced absorptions in the semiconductor and lossy metal layers exploiting strong interference effects and can be maintained over a wide viewing angle up to ±60°. Benefiting from the lossy metal providing additional absorption, our design reduces the requirement for the semiconductor's material dispersion and has great flexibility in the material selection of the metal layer. Additionally, the lithography-free nature of the proposed broadband visible absorber provides a high-throughput fabrication convenience, thus holding great potential for its large-area applications in various fields.

Reflective Full‐Color Structural Colors with High Brightness and High Purity Based on Ge2Sb2Se4Te1 Chalcogenide Film

AbstractThis study proposes a general strategy for constructing an asymmetric Fabry–Perot structure based on an ultra‐thin composite absorber, Ni/Ge2Sb2Se4Te1, to produce reflective full‐color structural colors with high brightness and purity. The composite absorber effectively enhances the strong interference effect of thin film, which can significantly reduce the reflection bandwidth of the target band and the reflectivity of the non‐target band. Under the premise of optimizing the five‐layer base structure, full‐color structural colors can be tuned by only changing the thickness of the LaTiO3 layer. Using the ion‐assisted electron beam evaporation technique, a simple and efficient film deposition process, six color devices (namely red, orange, yellow, green, blue, and purple) are successfully prepared with reflection peaks exceeding 90%. The chromaticity coordinates of the proposed high‐purity red, green, and blue (RGB) samples are (0.554, 0.339), (0.280, 0.600), and (0.164, 0.075), respectively. These coordinates are fairly close to the standard RGB color coordinates used in liquid crystal displays. This device has a simple structure with a novel material combination and a low production cost, which makes it feasible for mass production using just one coating run process. It has excellent application potential in various fields such as micro‐nano displays, anti‐counterfeiting measures, reflective color filters, and decorations.

The dynamic characteristics in the wake systems of a propeller operating under different loading conditions

Improved delayed detached-eddy simulations (IDDES) on the computational domain composed of 48 million cells were employed to numerically simulate the propeller wake with various advance coefficients, shedding light on the dynamic characteristics and the evolution mechanisms for the entire wake system subject to different loading conditions. Validation against available experimental data under open water configuration was conducted to verify the numerical modelling in the present work. Dynamic mode decomposition, or to be more specific, its sparisity promoting varient, was further adopted to capture the fundamental spatio-temporal scales of the propeller wakes. The results of the simulation revealed that the low streamwise convection velocity with the high advance coefficient suppresses the wake vortex transportation, resulting in a helicoidal tip vortex system with strong interference effects and low pitch that leads to the earlier occurrence of propeller wake instability. The wake systems with high advance coefficient better maintain the memory of propeller rotation, resulting in more coherent downstream wakes. Moreover, the different interaction modes leading to wake instability were discussed.

Price limit hits in the Chinese fund market: Determinants and post-hit performance

This article examines the predictors of price limit hits and post-hit market behaviors in the Chinese fund market. We show that macroeconomic news, past market returns, lagged limit hit dummies, and lagged price deviations have significant predictive powers for limit hits. We find that there is asymmetry between upper and lower limits, and between positive news and negative news. Furthermore, our tests of post-hit market dynamics provide evidence of volatility spillover after news upper-limit hits and no-news lower-limit hits. We find delayed price discovery except for no-news lower-limit hits, and a strong short-lived trading interference effect for news lower-limit hits. The price deviation is larger after news lower-limit hits but smaller after news upper-limit hits.

Interference effects in polarization-controlled Rayleigh scattering in twisted bilayer graphene

We calculate the \tco{polarization}-controlled Rayleigh scattering response of twisted bilayer graphene (tBLG) based on the continuum electronic band model developed by Bistritzer and MacDonald while considering its refinements which address the effects of structural corrugation, doping-dependent Hartree interactions and particle-hole asymmetry. The dominant wave vectors for the Rayleigh scattering process emanate from various regions of the Moir\'e Brillouin zone (MBZ) in contrast to single-layer graphene (SLG) and AB-stacked bilayer graphene (AB-BLG), where the dominant contributions always stem from the vicinity of the $\bm{K}$ point for optical laser energies and below. Compared to SLG, the integrated Rayleigh intensity is strongly enhanced for small twist angles (\emph{e.g.}, at a twist angle $ \theta = 1.2^{\circ} $, the integrated Rayleigh intensity at laser energy $ E_l=2~\si{\electronvolt} $ enhances by a factor of $\sim $ 100 for the case of parallel \tco{polarization}). While for the case of cross-\tco{polarization}, it exhibits a markedly complex \tco{behavior} suggestive of strong interference effects mediated by the optical matrix elements. We find that at small twist angles, \emph{e.g.}, $ \theta = 1.05^{\circ} $, the corrugation effects strongly enhances the ratio $ \bm{R}_A = \frac{ \text{integrated Rayleigh intensity for parallel \tco{polarization}}}{\text{integrated Rayleigh intensity for cross-\tco{polarization}}} $ by $ \sim $ $ 1300 $ times \emph{viz a viz} SLG or AB-BLG.

Interference effects in harmonic ellipticity from H molecules in an orthogonally polarized two-color laser field

We theoretically investigate the elliptically polarized harmonics from aligned molecular ion H in orthogonally polarized two-color laser pulses. Our results show that a striking peak appears in the ellipticity curve of odd-order harmonics, and this peak shows obvious alignment dependence and shifts toward higher energy as the amplitude ratio of the two colors increases. The location of the peak is close to that of the interference minimum predicted by using a modified dipole model, indicating strong two-center interference effects in ellipticity. Through adjusting the frequency ratio of the two colors, large ellipticity is obtained for both odd and even harmonics in a wide energy region. As a result, we synthesize a bright, elliptically polarized, isolated attosecond pulse with an ellipticity up to 0.63.

Analysis of the dehydration performance in a two-phase variable-section gas wave oscillation tube

The two-phase gas wave oscillation tube (TPGWOT) is subjected to several problems in the application of moisture-containing gas dehydration (e.g., less accurate prediction of the results of phase transition in the tube, and strong interference effect of reverse compression waves in the tube). The predicted phase transition results approach the experimental values by coupling the CPA real gas model and the non-equilibrium phase transition model. The performance of the proposed variable-section TPGWOT is investigated using numerical and experimental methods, and the following results are achieved. The variable-section structure is capable of optimizing the wave system in the tube, as manifested by the ability to strengthen the reflected expansion wave and weaken the reverse compression waves. As a result, the maximum condensation rate of condensate droplets is increased by 2 % to 5 %, and the proportion of evaporation capacity of condensate droplets is reduced by 3 % to 7 %. The variable-section structure is capable of enhancing the performance of the GWOTs, as manifested by the ability to improve the gas temperature drop (ΔT) of nearly 20 % and increase the dehydration rate by 2.6 % to 5 %. This study is no longer limited to optimizing the wave system in the tube by changing the ports at both ends of TPGWOTs, and it provides a favorable reference for other wave rotor application research.

A finite element study on the influence of surface cracks on micro-contact impedance spectroscopy measurements

Micro-contact impedance spectroscopy (MCIS) is a powerful tool to analyse local features of interest in electroceramics. The surface condition of the measured area of interest however may not always be ideal. Surface defects such as cracks may be present and therefore influence the measured MCIS data, especially for a top-top electrode configuration. Here we develop a finite element model on a system where a crack of various dimensions exists on the top surface between two surface micro-contact electrodes. We show how a crack can influence the current distribution within the sample and its effect in evaluating the MCIS data and associated extracted conductivity values. When the micro-contact separation is low, the hindrance effect forming from a crack acts to counterbalance the strong current interference effect that originates from closely placed top-top electrodes. The crack depth and length prove to be more effective than crack width in terms of counterbalancing interference. As the micro-contact separation increases, both current interference and crack hindrance decreases. Cracks in a specimen may therefore fortuitously assist in offsetting significant current interference effects, especially at the micro-contact separations used in many experimental set-ups.

An efficient sparse method for direction-of-arrival estimation in the presence of strong interference.

Target direction-of-arrival (DOA) estimation is often difficult in the presence of strong interference-especially when the target DOA is very close to the interference DOA-since the strong interference signal can mask the weak target signal and make the DOA estimation hard. To address this problem, an efficient sparse method for DOA estimation is proposed in this paper, in which the effect of strong interference on the target DOA estimation is significantly reduced. An on-grid version of the grid evolution technique is then developed to nonuniformly refine the grid, thereby reducing the computational complexity while retaining reasonable accuracy. Numerical simulations and experimental results demonstrate that, compared to state-of-art methods, the proposed method achieves higher efficiency and better DOA estimation performance in the presence of strong interference.

Scalable Superabsorbers and Color Filters Based on Earth-Abundant Materials.

Optical materials based on unconventional plasmonic metals (e.g., magnesium) have lately driven rising research interest for the quest of possibilities in nanophotonic applications. Several favorable attributes of Mg, such as earth abundancy, lightweight, biocompatibility/biodegradability, and its active reactions with water or hydrogen, have underpinned its emergence as an alternative nanophotonic material. Here, we experimentally demonstrate a thin film-based optical device composed exclusively of earth-abundant and complementary metal-oxide semiconductor (CMOS)-compatible materials (i.e., Mg, a-Si, and SiO2). The devices can exhibit a spectrally selective and tunable near-unity resonant absorption with an ultrathin a-Si absorbing layer due to the strong interference effect in this high-index and lossy film. Alternatively, they can generate diverse reflective colors by appropriate tuning of the a-Si and SiO2 layer thicknesses, including all the primary colors for RGB (red, green, blue) and CMY (cyan, magenta, yellow) color spaces. In addition, the reflective hues of the devices can be notably altered in a zero power-consumption fashion by immersing them in water due to the resulted dissolution of the Mg back-reflection layer. These compelling features in combination with the lithography-free and scalable fabrication steps may promise their adoption in various photonic applications including solar energy harvesting, optical information security, optical modulation, and filtering as well as structure reuse and recycling.

High-resolution real-space evaluation of the self-energy operator of disordered lattices: Gade singularity, spin–orbit effects and p-wave superconductivity

Disorder is a key factor influencing the behavior of condensed states of matter, however the true extent of its impact is generally difficult to determine due to the prominent roles played by quantum interference, entanglement between spin and orbital degrees of freedom and proximity to quantum critical points. Here we show that the one-particle disorder self-energy—a direct probe of the renormalization of low-energy excitations due to defects and impurities distributed randomly in a crystal—can be obtained by means of unbiased spectral expansions of lattice Green’s functions in a computationally expedient manner. Our scheme provides a powerful framework to map out the frequency and wavevector dependence of electronic excitations in unprecedented large tight-binding systems, up to 109 orbitals, with energy resolution only limited by the mean level spacing. We demonstrate the versatility of our approach in three distinct problems: (i) the Gade singularity in honeycomb layers with dilute topological defects; (ii) the rich landscape of impurity resonances in a spin–orbit-coupled ferromagnet; and (iii) the tailoring of emergent s-wave and p-wave superconducting phases in graphene via atomic defects. These examples reveal rich features in the disorder self-energy that are absent from the self-consistent T-matrix approach and other common approximation schemes, which include regimes of nontrivial wavevector dependence and anomalous dependence upon the impurity concentration. Our study unravels puzzling, and so far largely inaccessible, manifestations of strong nonperturbative quantum interference effects in quantum materials and disordered phases of matter.

Anisotropic mode excitations and enhanced quantum interference in quantum emitter-metasurface coupled systems

This study proposes a nanophotonic structure that supports quantum interference (QI) between orthogonal decay channels in multilevel quantum emitters within the framework of the quantum master equation. The Green functions of the electric field are obtained by applying boundary conditions in the presence of two-dimensional metasurfaces. We demonstrate distinct in-plane excitation features of the surface plasmon modes (SPMs) with the anisotropic metasurfaces tailored to conductivity components. In particular, we observed that the Purcell factor of transitions with orthogonal polarizations experiences unequal enhancements, owing to the anisotropic propagation of the SPMs. This property depends only on the anisotropy of the metasurfaces; thus, it is easily manipulated. Using this platform and considering experimentally achievable material parameters, we predict a strong interference effect in three-level quantum emitters. In principle, this enables the generation of maximum QI. Our study provides a method for realizing QI systems and has potential applications in highly integrated, tuneable quantum devices.