Phenomenon Of Repulsion Research Articles

An explanation for the sister repulsion phenomenon in Patterson's f-statistics.

Patterson's f-statistics are among the most heavily utilized tools for analyzing genome-wide allele frequency data for demographic inference. Beyond studying admixture, f3- and f4-statistics are also used for clustering populations to identify groups with similar histories. However, previous studies have noted an unexpected behavior of f-statistics: multiple populations from a certain region systematically show higher genetic affinity to a more distant population than to their neighbors, a pattern that is mismatched with alternative measures of genetic similarity. We call this counter-intuitive pattern "sister repulsion". We first present a novel instance of sister repulsion, where genomes from Bronze Age East Anatolian sites show higher affinity toward Bronze Age Greece rather than each other. This is observed both using f3- and f4-statistics, contrasts with archaeological/historical expectation, and also contradicts genetic affinity patterns captured using principal components analysis or multidimensional scaling on genetic distances. We then propose a simple demographic model to explain this pattern, where sister populations receive gene flow from a genetically distant source. We calculate f3- and f4-statistics using simulated genetic data with varying population genetic parameters, confirming that low-level gene flow from an external source into populations from 1 region can create sister repulsion in f-statistics. Unidirectional gene flow between the studied regions (without an external source) can likewise create repulsion. Meanwhile, similar to our empirical observations, multidimensional scaling analyses of genetic distances still cluster sister populations together. Overall, our results highlight the impact of low-level admixture events when inferring demographic history using f-statistics.

The interaction between filaments in dielectric barrier discharge excited by bipolar/unipolar nanosecond pulse powers

This study investigates the behavior of discharge filaments in dielectric barrier discharges with a focus on the effects of nanosecond pulse voltage polarity. We observed significant repulsion between discharge filaments when the pin electrode was grounded in bipolar nanosecond pulse discharge. The tilt angle of the filaments was directly proportional to the peak current, which is indicative of charge density. When the bare pin electrode acted as an H.V. electrode, the repulsion phenomenon was diminished. Surface charges released through the bare pin electrode instead of accumulated on the dielectric surface accounts for this phenomenon. The study also highlights the impact of bipolar versus unipolar nanosecond pulse powers. The addition of a water resistor (WR) results in a slower falling edge of the pulse voltage and the absence of subsequent reverse discharges. The repulsion between filaments disappears both in pin-to-ground discharge and pin-to-H.V. discharge. The introduction of WR leads to a reduction of the current pulse’s duration and a premature termination of the discharge process, resulting the influence of surface charges on filament positioning negligible. It is hypothesized that the spatial distribution of ions does not exhibit significant repulsion, attributed to their substantial mass and sparse distribution in space.

Oxyhydrogen-air explosion characteristics in water jetting propulsion

Hydrogen has attracted many researchers in the field of explosion jetting propulsion owing to its appealing advantages of zero carbon emissions, wide flammability range, and ease of preparation. However, the research gap in hydrogen explosion characteristics in water jetting scene has slowed down the advancement of the impulsive jetting propulsion field. In this work, static tests under three typical explosion jetting scenes (vertical submerged jetting, oblique submerged jetting, and aerial jetting) are conducted to reveal their explosion and thrust characteristics. The static tests results demonstrate that although the peak pressures of the aerial and vertical submerged explosion jettings are comparable, the peak thrust of the former is dramatically reduced by 40.6 %. We also find that the maximum pressure rise rate and peak pressure of the oblique submerged jetting are 22.9 % and 11.4 % lower than those of the vertical submerged jetting, respectively. Meanwhile, the peak thrust of the inclined jetting is also reduced by 14.1 % compared to the vertical jetting. High-speed photography applied to capture the evolution details of the oxyhydrogen-air explosion reveals that the preceding differences are attributed to the asymmetrical water repulsion phenomenon. Specific impulse is used to characterize the propulsion performance of the oxyhydrogen-air–water explosion jetting at varied volume fractions, and the results show that the maximum specific impulse is obtained for a given 0.45 kg thruster at 40 % water volume and 4:6 ratio of air to oxyhydrogen. The correctness of the explosion characterization metrics and thrust results are finally corroborated via the outdoor aquatic-aerial jetting propulsion tests.

Comparative Efficacy of Madrid Plant Extracts in Controlling Red Flour Beetle Populations: A Laboratory Evaluation of Alcohol and Aqueous Solutions

The efficiency of the alcohol and aqueous excerpt from the Madrid plant in killing ratios of colour red cover beetle larvae and adults afterwards behaviours lasting 24, 48, and 72 hours was valued in laboratory research. Three dissimilar Madrid plant absorptions (1.50 per cent, 3.0%, and 4.59 per cent) were selected to stop the beetle's larvae and adults. The outcomes displayed that the Madrid plant excerpt formed notable degrees. Following 72 hours, the watery excerpt's adult expiry rate was 33.0%, while the alcohol excerpt was 60.0% at 3.0% absorption. After 72 hours, the alcohol excerpt is concentrated larval expiry rate was 71.0% at 3.0% absorption; whereas the watery excerpt's extreme rate was 66.0%. After it derives the phenomena of attraction and repulsion, the paper initiates that the Madrid excerpt in the watery form displayed the maximum level of pull, reaching 9.30% at the absorption of 3.0% after 72 hours, while the repulsion rate was 15.550% at the similar absorption and time. Following 48 hours, the alcohol excerpt of Madrid showed a pull rate of 12.550% at 1.50% concentration. Additionally, following 72 hours, a revulsion rate of 19.80% at 3.0% concentration was realized in adult beetles. The extreme pull rate of the watery excerpt for larvae was 0.00% at all absorptions, and after 72 hours, a comparable revulsion rate of 10.950% was realized at a 4.50% concentration. Also, after 72 hours, the alcohol excerpt displayed a revulsion rate of 19.150% at 3.0% absorption and a pull rate of 0.00% at all concentrations.

Single-Electrode Electrostatic Repulsion Phenomenon for Remote Actuation and Manipulation.

One of the fundamental principles of electrostatics is that an uncharged object will be attracted to a charged object through electrostatic induction as the two approaches one another. We refer to the charged object as a single electrode and examine the scenario where a positive voltage is applied. Because of electrostatic induction phenomenon, single-electrode electrostatics only generates electrostatic attraction forces. Here, we discover that single-electrode electrostatics can generate electrostatic repulsion forces and define this new phenomenon as single-electrode electrostatic repulsion phenomenon. We investigate the fundamental electrostatic phenomena, giving a curve of electrostatic force versus voltage and then defining 3 regions. Remote actuation and manipulation are essential technologies that are of enormous concern, with tweezers playing an important role. Various tweezers designed on the basis of external fields of optics, acoustics, and magnetism can be used for remote actuation and manipulation, but some inherent drawbacks still exist. Tweezers would benefit greatly from our discovery in electrostatics. On the basis of this discovery, we propose the concept of electrostatic tweezers, which can achieve noncontact and remote actuation and manipulation. Experimental characterizations and successful applications in metamaterials, robots, and manipulating objects demonstrated that electrostatic tweezers can produce large deformation rates (>6,000%), fast actuation (>100 Hz), and remote manipulating distance (~15 cm) and have the advantages of simple device structure, easy control, lightweight, no dielectric breakdown, and low cost. Our work may deepen people's understanding of single-electrode electrostatics and opens new opportunities for remote actuation and manipulation.

Attraction–Repulsion Optimization Algorithm for Global Optimization Problems

In this study, a novel meta-heuristic search (MHS) algorithm for constrained global optimization problems is proposed. Since many algorithms aim to achieve well-balanced exploitation–exploration stages with often unsatisfactory results, in the approach introduced in this paper, Attraction–Repulsion Optimization Algorithm (AROA), the balance associated with attraction–repulsion phenomena that occur in nature is mimicked. AROA introduces a search strategy in which a candidate solution is moved in the search space depending on the quality of solutions in its neighborhood, as well as the best candidate. The candidates are managed by local search operators based on modified Brownian motion, trigonometric functions, randomly selected solutions, and a form of memory. Consequently, AROA exhibits a satisfactory exploitation–exploration balance exhibited by highly competitive performance. The introduced algorithm is experimentally compared with the state-of-the-art meta-heuristics on the CEC 2014, 2017, and 2020 test suites. The obtained results reveal the advantages of AROA over related algorithms and its suitability in solving complex real-world problems.

A female-specific odorant receptor mediates oviposition deterrence in the moth Helicoverpa armigera

Finding ideal oviposition sites is a task of vital importance for all female insects. To ensure optimal conditions for their progeny, females of herbivorous insects detect not only the odors of a relevant host plant but also chemicals released by eggs, named oviposition-deterring pheromones (ODPs). It is reported that such chemicals play critical roles in suppressing female oviposition behavior; however, the molecular mechanism underlying the detection of egg-derived ODPs remains elusive. Here, we have identified three specific fatty acid methyl esters from the surface of eggs of Helicoverpa armigera serving as ODPs-methyl oleate (C18:1ME), methyl palmitate (C16:0ME), and methyl stearate (C18:0ME). We demonstrated that these ODPs are detected by the receptor, HarmOR56, exclusively expressed in sensilla trichodea on female antennae. To assess the significance of this receptor, we disrupted HarmOR56 in H.armigera using CRISPR-Cas9 and found that mutant females did not respond to the ODPs, neither in behavioral nor in electrophysiological tests. We therefore conclude that HarmOR56 is indispensable for identifying the ODPs. This study explores, for the first time, how a female-specific odorant receptor detects chemicals from conspecific eggs. Our data elucidate the intriguing biological phenomenon of repulsion to conspecific eggs during oviposition and contribute new insight into a female-specific olfactory pathway linked to reproduction.

Effect of contact angle hysteresis on measuring matric suction in unsaturated sandy soil

The contact angle plays an important role in matric suction of unsaturated soils, but few studies consider the effect of contact angle hysteresis on matric suction. In this paper, taking sandy soil as an example, the influence of contact angle hysteresis on the suction of unsaturated soil matric is studied by soil particle model calculation and experimental method. The results show under the same water content condition, the smaller the contact angle is, the larger the matric suction is and the phenomenon of water repellency appears. Under the low water content of unsaturated soil, when the contact angle is less than 90°, it will also produce water repulsion phenomenon, which is different from the hydrophilic characteristics of the contact angle is less than 90° in the capillary law. When the water content is the same, with the increase of contact angle, matric suction will decrease. With the increase of water content, matric suction is not affected by soil contact angle. In the process of dehumidification, the apparent contact angle of the sandy soil with the same water content less than receding contact Angle; there is a difference in matric suction between continuous measurement method and discontinuous measurement method, and continuous measurement’ matric suction greater than discontinuous measurement’ matric suction. This study provides some theoretical basis and reference for the study of matric suction of unsaturated soil.

Analytical three-periodic solutions of Korteweg–de Vries-type equations

Based on the direct method of calculating the periodic wave solution proposed by Nakamura, we give an approximate analytical three-periodic solutions of Korteweg–de Vries (KdV)-type equations by perturbation method for the first time. Limit methods have been used to establish the asymptotic relationships between the three-periodic solution separately and another three solutions, the soliton solution, the one- and the two-periodic solutions. Furthermore, it is found that the asymptotic three-soliton solution presents the same repulsive phenomenon as the asymptotic three-soliton solution during the interaction.

Charged Particle Attraction and Repulsion Explained: A Detailed Mechanism Based on Particle Wave-Functions

The phenomenon of electrical attraction and repulsion between charged particles is well known, and described mathematically by Coulomb’s Law, yet until now there has been no explanation for why this occurs. There has been no mechanistic explanation that reveals what causes the charged particles to accelerate, either towards or away from each other. This paper gives a detailed explanation of the phenomena of electrical attraction and repulsion based on my previous work that determined the exact wave-function solutions for both the Electron and the Positron. It is revealed that the effects are caused by wave interactions between the particles’ wave-functions that result in Electromagnetic reflections of parts of these wave-functions, causing a change in the particles’ momenta.

Temporal resolution and temporal extent of orientation repulsion

A vertical target is perceived as tilted against a slightly tilted inducer surrounding it. To identify the temporal resolution and temporal extent of this phenomenon of orientation repulsion in the same paradigm, we used an alternating pair of inducer stimuli having complementary orientation distributions and quantified repulsion at various alternation frequencies. The duration of each inducer stimulus was inversely proportional to the frequency. When an orthogonal pair of D2 patterns, a type of grating whose luminance modulation in a particular orientation was the second-order partial derivative of an isotropic 2D-Gaussian, was used as the inducer, repulsion occurred when the duration exceeded 20 ms and leveled off at 30 ms and beyond. When a custom-made texture with a narrowband orientation distribution and another texture with a complementary orientation distribution were alternated as the inducer, repulsion gradually increased until the inducer duration reached 200 ms. The gradual increase in repulsion was observed regardless of whether the orientation of the inducer that appeared simultaneously with the target was discernible. These findings reveal that contextual modulation in orientation occurs at a high temporal resolution and continues to a long temporal extent under optimal conditions.

Eigenvalue repulsions and quasinormal mode spectra of Kerr-Newman: an extended study

The frequency spectra of the gravito-electromagnetic perturbations of the Kerr-Newman (KN) black hole with the slowest decay rate have been computed recently. It has been found that KN has two families — the photon sphere and the near-horizon families — of quasinormal modes (QNMs), which display the interesting phenomenon of eigenvalue repulsion. The perturbation equations, in spite of being a coupled system of two PDEs, are amenable to an analytic solution using the method of separation of variables in a near-horizon expansion around the extremal KN black hole. This leads to an analytical formula for the QNM frequencies that provides an excellent approximation to the numerical data near-extremality. In the present manuscript we provide an extended study of these properties that were not detailed in the original studies. This includes: 1) a full derivation of a gauge invariant system of two coupled PDEs that describes the perturbation equations [1], 2) a derivation of the eikonal frequency approximation [2, 3] and its comparison with the numerical QNM data, 3) a derivation of the near-horizon frequency approximation [3] and its comparison with the numerical QNMs, and 4) more details on the phenomenon of eigenvalue repulsion (also known as level repulsion, avoided crossing or Wigner-Teller effect) and a first principles understanding of it that was missing in the previous studies. Moreover, we provide the frequency spectra of other KN QNM families of interest to demonstrate that they are more damped than the ones we discuss in full detail.

Level Repulsion for Arithmetic Toral Point Scatterers in Dimension 3

We show that arithmetic toral point scatterers in dimension three (“Šeba billiards on {mathbb R}^3/{mathbb Z}^3”) exhibit strong level repulsion between the set of “new” eigenvalues. More precisely, let Lambda := { lambda _{1}< lambda _{2} < ldots } denote the unfolded set of new eigenvalues. Then, given any gamma >0, |{i≤N:λi+1-λi≤ϵ}|N=Oγ(ϵ4-γ)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\begin{aligned} \\frac{|\\{ i \\le N : \\lambda _{i+1}-\\lambda _{i} \\le \\epsilon \\}|}{N} = O_{\\gamma }(\\epsilon ^{4-\\gamma }) \\end{aligned}$$\\end{document}as N rightarrow infty (and epsilon >0 small.) To the best of our knowledge, this is the first mathematically rigorous demonstration of a level repulsion phenomena for the quantization of a deterministic system.

Intrinsic Vortex–Antivortex Interaction of Light

AbstractThe spin–orbit interaction and the extrinsic orbit–orbit interaction of light have been thoroughly studied, which have led to important phenomena including the spin Hall effect, orbital Hall effect, and spin–orbit Hall effect of light. Nevertheless, the concept of optical intrinsic orbit–orbit interaction, which is named as vortex–antivortex interaction, is scarcely known to the authors knowledge. Here, such a novel interaction process is theoretically and experimentally demonstrated, which emerges due to mutual interplays among reciprocal helicities of singular cores in a freely propagating light field. A general model describing the process is presented, which includes a linearly independent term and a nonlinearly coupling term. It is revealed that the strong coupling leads to intuitive mutual attraction between two reciprocal vortices, while the weak coupling, in contrast, results in a counterintuitive repulsive phenomenon. The vortex–antivortex interaction enables the predictions and observations of the orbital angular momentum Hall effect, as well as the stable propagation of an appropriately structured vortex arrays without nonlinear light–matter interactions. The results expand the scope of interaction processes among different forms of optical angular momenta, and open opportunities for studies of new effects using the presented coupling mechanism.

Characterization Method of the V-shaped High-Temperature Superconducting Maglev Module for Transport System Applications

AbstractIt is now recognized that high-temperature superconducting (HTS) technology has a significant potential for future magnetic levitation (Maglev) transit system applications due to the advantages of self-stable levitation, being free of electric power and magnetic drag to the vehicle motion, and system simplicity. This article provides a characterization method of the experimental transport system Maglev levitation module developed at the University of L’Aquila (Italy). More specifically, the lifting and guiding behavior of a single V-shaped Maglev module, which is unique for this type of application, is analyzed and tested. Its working principle is based on the interaction between HTS “skate” onboard of the vehicle and the magnetic field generated by the permanent magnets distributed on the guideway (PMG). A single scaled levitation module was built and tested under quasi-static conditions using dedicated measuring equipment by varying system parameters such as vertical gap, lateral offset, and field cooling height. The latter determines the amount of interacting magnetic field that is trapped in the HTS core during its transition from the resistive to the superconducting state and which, in turn, interacts with the field generated by the PMG to create the suspension phenomenon. The Maglev module’s dual behavior due to the double phenomenon of repulsion and attraction has been verified and tested in terms of vertical and lateral forces by varying system parameters. The dual “push and pull” force allows the phenomenon of vehicle driving to be enhanced.

Electromagnetic Interaction: A New Theoretical Approach

All the four fundamental interactions describe phenomena of attraction except one, the electromagnetic interaction, which also describes phenomena of repulsion. If the matter that constitutes our universe is subject to the same physical laws, then the four fundamental interactions should all express the same phenomena: either attraction or repulsion. In this work, a new approach called the binding cord approach was introduced to describe the electromagnetic interaction. In this new approach, electromagnetic repulsion will be described as a consequence of attraction.

Driven dissipative quantum dynamics in a cavity magnon-polariton system

The dynamics of arbitrary-order quantum correlations in a cavity magnon-polariton system are investigated based on the quantum master equation in the coherent state representation. The phenomena of Rabi-like oscillation and level repulsion of the average cavity-photon number agree remarkably well with existing experimental observations. The competing nature of coherent and incoherent components in these two cases is further revealed by the second-order quantum coherence of the cavity photons and magnons, which can be systematically tuned by the driving microwave and thermal bath. Our results demonstrate the rich higher-order quantum dynamics induced by magnetic light-matter interaction, and serve as an indispensable step toward exploring nonclassical states for cavity photons and magnons in quantum cavity magnonics.

Suppression of the repulsion phenomenon of magnetic skyrmions at the end of synthetic antiferromagnetic racetracks

The synthetic antiferromagnetic (SAF) racetracks can perfectly suppress the skyrmion Hall effect, but the congestion phenomenon of the skyrmions at the end of the racetracks will seriously hinder the development of the skyrmion-based magnetic storage technology. In this paper, we have designed and investigated three racetrack structures of double-layer triangular notch, single-layer triangular notch (SLTN) and square hole-triangular notch (SHTN) in SAF racetracks by micromagnetic simulations. The critical current density that annihilates skyrmions in a racetrack with triangular notches is closely related to the angle of the triangular notches and decreases with the decrease of the angles. If a skyrmion in the top ferromagnetic (FM) layer of SLTN structure is annihilated, its counterpart in the bottom FM layer will also be annihilated due to the interlayer antiferromagnetic exchange coupling. Compared with the critical current density of 3.0 × 1012 A m−2 in a normal racetrack, the critical current density of SHTN structure can be dropped to 6.0 × 1010 A m−2. The results reveal that all the three structures can significantly reduce the critical current density, which can effectively solve the skyrmion congestion at the end of the racetracks.

Novel aluminum vanadate as a cathode material for high-performance aqueous zinc-ion batteries

Rechargeable aqueous zinc-ion batteries (AZIBs) have garnered widespread attention as a new large-scale energy storage candidate owing to their low cost and high theoretical capacity. Because of the unique divalent state of Zn2+ and the existence of a strong electrostatic repulsion phenomenon, researchers are currently focusing on how to prepare high-performance cathode materials. In this study, we synthesized aluminum vanadate (AlV3O9) as a cathode material for AZIBs using a solvothermal method. Al3+ acted as a pillar in the resultant structure and stabilized it. Furthermore, this large interlayer spacing enhanced the ion diffusion coefficient and accelerated the ion transport process. Because of these advantages, the AlV3O9 (AVO) cathode exhibited excellent electrochemical performance, including a high capacity of 421.0 mA h g−1 at 0.1 A g−1 and a stable rate capability of 348.2 mA h g−1 at 1 A g−1. Moreover, it exhibited a specific capacity of 202 mA h g−1 even at a high current density of 3 A g−1 (the capacity retention rate reached 84.38% after 1600 cycles). The prepared ZIBs presented a high power density of 366.6 W kg−1 at an energy density of 286 W h kg−1. These extraordinary results indicate the great application potential of AVO as a cathode material for AZIBs.

Interfacial instability of sand patterns induced by turbulent shear flow

When a turbulent shear flow above a plane sand surface entrains sand grains, it generates a variety of sand patterns. Fluvial sand forms two major interfacial patterns: meso-scale dunes and antidunes, and large-scale bars. Measurements have evidenced that under erosive conditions, meso-scale patterns either change to or coexist with large-scale patterns. However, it remains elusive what exactly drives the switching of interfacial patterns and how the switching occurs. Here, we show—combing a flow model with a grain transport model, allowing for both the surface and suspended sand fluxes—that the switching of patterns emerges from the shear-driven complex feedback between grain transport and topographic perturbations. The switching predominantly depends on the magnitudes of the Rouse number and the grain size to undisturbed flow depth ratio. The model offers quantitative predictions of the maximum amplification of sand patterns and unveils a new attraction–repulsion phenomenon.