Polarization Distance Research Articles

Political polarization and intimate distance: Negotiating family conflicts during a high-risk protest movement

Political polarization not only threatens democracy, but also disrupts family lives, causing clashes between family members with discordant political orientations. This article examines how individuals negotiate family conflicts during political divides, by focusing on the Anti-Extradition Bill Movement in Hong Kong. Based on data drawn from interviews conducted with 37 self-identified protest participants, I develop the concept of intimate distance in order to capture the way in which the participants negotiated political disagreements with their immediate family. Individuals make peace with their families during a high-risk movement, not merely by restoring closeness, but also by adjusting the intimate distance with their family members in three interconnected aspects: everyday family life, cognitive and emotional aspects. Individuals employ a repertoire of practices, together with emotion work and boundary work, to alleviate confrontations, rebuild consensus, and contain political risks. This study contributes to a more nuanced conceptualization of intimacy and family conflict resolution, and unravels the impact of family interactions on the intensification or alleviation of ideological and affective polarization in relation to the interpersonal and societal level.

Switchable terahertz orbital angular momentum Bessel beams based on spin-decoupled multifunctional reflective metasurfaces.

In this study, switchable terahertz (THz) multi-orbital angular momentum (OAM) Bessel beams (BBs) were developed based on a spin-decoupled reflective multifunctional metasurface (MTS). Switchability was achieved by switching the feed between left-hand circular polarization (LCP), right-hand circular polarization (RCP), and linear polarization (LP) incidences. A switchable physical model was established for calculating the beam direction, OAM mode, polarization, and non-diffractive distance of the outgoing BBs. As an example, a spin-decoupled MTS was designed to generate dual BBs under LCP incidence, which was subsequently switched to RCP or LP for switchability. The outgoing BBs could be switched among three types of beams: Type-1 under LCP incidence (LCP, θL = 40°, φL = 0°, lL = 1, dL = 18 cm) and (RCP, θR = -40°, φR = 0°, lR = -1, dR = 20 cm); Type-2 under RCP incidence (RCP, θR = 40°, φR = 0°, lR = 1, dR = 18 cm) and (LCP, θL = -19°, φL = 0°, lL = 3, dL = 16.4 cm); and Type-3 under LP incidence (LP, θ = 40°, φ = 0°, l = 1, d = 18 cm), (RCP, θR = -40°, φR = 0°, lR = -1, dR = 20 cm) and (LCP, θL = -19°, φL = 0°, lL = 3, dL = 16.4 cm). Compared with previous MTSs, the proposed spin-decoupled MTS has the advantages of switchability among BBs, high non-diffractive distance/aperture size ratio of 15, large beam deflection angle of up to 40°, and high BB conversion efficiency of up to 96%. The simulated results were consistent with those calculated using the physical model, thus validating the physical model. The designed switchable BBs have potential THz near-field applications, such as high-capacity near-field wireless communications, wireless power transfer, high-resolution imaging, non-destructive testing, and speed detection of high-speed rotating objects.

Noise-aware infrared polarization image fusion based on salient prior with attention-guided filtering network.

Infrared polarization image fusion integrates intensity and polarization information, producing a fused image that enhances visibility and captures crucial details. However, in complex environments, polarization imaging is susceptible to noise interference. Existing fusion methods typically use the infrared intensity (S0) and degree of linear polarization (DoLP) images for fusion but fail to consider the noise interference, leading to reduced performance. To cope with this problem, we propose a fusion method based on polarization salient prior, which extends DoLP by angle of polarization (AoP) and introduces polarization distance (PD) to obtain salient target features. Moreover, according to the distribution difference between S0 and DoLP features, we construct a fusion network based on attention-guided filtering, utilizing cross-attention to generate filter kernels for fusion. The quantitative and qualitative experimental results validate the effectiveness of our approach. Compared with other fusion methods, our method can effectively suppress noise interference and preserve salient target features.

Algorithm of Target Enhancement Under Shadow that Combining Polarization Distance and Color Space

Algorithm of Target Enhancement Under Shadow that Combining Polarization Distance and Color Space

Polarization and conflict among groups with heterogeneous members

We analyze the choice of the policy platform that a group of heterogeneous challengers will support to confront the current policy in a subsequent contest between them and the status-quo defenders. The choice of this alternative policy will affect not only the incentives of challengers to get involved in the conflict (intra-group effect), but also the mobilization of status-quo defenders (inter-group effect). We disentangle these two effects and show that the degree of polarization (distance between the alternative and the status-quo policy) depends on how the efforts that groups exert in the contest affect their winning probabilities. Our results illustrate how the conflict resolution rules may affect the degree of polarization in political confrontations.

Revealing the dust grain polarization properties as a function of extinction and distance towards NGC 1893

ABSTRACT Dust polarization observations at optical wavelengths help us to understand the dust grain properties and trace the plane-of-the-sky component of the magnetic field. In this study, we make use of the I-band polarization data acquired from AIMPOL along with the distances (d) and extinction (AV) data to study the variation of polarization fraction (P) as a function of AV and d towards the star-forming region, NGC 1893. We employ a broken power-law fit and Bayesian analysis on extinction (AV) versus polarization efficiency (P/AV) and distance (d) versus rate of polarization (P/d). We find that P/AV shows a break at an extinction of ∼0.9 mag, whereas P/d exhibits a break at a distance of ∼1.5 kpc. Based on these, we categorize the dust towards NGC 1893 into two populations: (i) foreground dust confined to AV < ∼1 mag and distance up to ∼2 kpc and (ii) Perseus spiral arm dust towards NGC 1893 characterized with AV > ∼1 mag and distance beyond ∼2 kpc. Foreground dust exhibits higher polarization efficiency but a lower polarization rate, whereas Perseus dust shows a lower polarization efficiency but a slightly higher polarization rate. Hence, we suggest that while polarization efficiency reveals the dust grain alignment, the rate of polarization infers about the distribution of dust grains towards NGC 1893. Further, we also shed a light on the spatial variation of intrinsic polarization and magnetic field orientation, and other parameters within the intracluster medium of NGC 1893.

Target–background contrast enhancement based on a multi-channel polarization distance model

Stomatopods are creatures that have a unique ability to manipulate their environment by detecting polarized light for finding prey, choosing habitat, and navigation. In this study, based on the concept of polarization distance proposed by Martin J et al 2014 [Proc. R. Soc. B 281, 20131632], we have analyzed several multi-channel polarization distance models. The simulation and experimental results revealed that compared to other models, a four-channel polarization distance model can significantly enhance the contrast between the target and the background, and it exhibits excellent performance in terms of scene discrimination capability and robustness to noise. The structure and signal processing method of this model are inspired by biological polarization vision such as that of mantis shrimps. According to this method, a polarization-vision neural network is simulated with four-orientation receptor information as the input, and the network connections are realized in a cascaded order. The target–background contrast enhancement method based on this model has wide application prospects in the field of camouflage removal and target detection.

Thresholds of polarization vision in octopuses.

ABSTRACTPolarization vision is widespread in nature, mainly among invertebrates, and is used for a range of tasks including navigation, habitat localization and communication. In marine environments, some species such as those from the Crustacea and Cephalopoda that are principally monochromatic, have evolved to use this adaptation to discriminate objects across the whole visual field, an ability similar to our own use of colour vision. The performance of these polarization vision systems varies, and the few cephalopod species tested so far have notably acute thresholds of discrimination. However, most studies to date have used artificial sources of polarized light that produce levels of polarization much higher than found in nature. In this study, the ability of octopuses to detect polarization contrasts varying in angle of polarization (AoP) was investigated over a range of different degrees of linear polarization (DoLP) to better judge their visual ability in more ecologically relevant conditions. The ‘just-noticeable-differences’ (JND) of AoP contrasts varied consistently with DoLP. These JND thresholds could be largely explained by their ‘polarization distance’, a neurophysical model that effectively calculates the level of activity in opposing horizontally and vertically oriented polarization channels in the cephalopod visual system. Imaging polarimetry from the animals’ natural environment was then used to illustrate the functional advantage that these polarization thresholds may confer in behaviourally relevant contexts.

Cross Polarized 2x2 LTE MIMO System for Automotive Shark Fin Application

In this research we propose two orthogonally placed FR4 printed planar monopole antenna elements for use in the automobile roof top shark fin antenna for LTE MIMO applications. The discussed MIMO antenna system is designed to cover the worldwide LTE frequency band from 698MHz to 2700MHz. The goal of this research is to achieve satisfactory MIMO performance across the whole band while staying within physical constraints of the shark fin style antenna. The target reflection coefficient (S11) of each element is -6dB. Because of physical constraints of the automotive shark fin design antenna MIMO decorrelation is achieved by cross polarization and small distance separation. Correlation better than -12dB is targeted and achieved in higher bands, while in lower frequency bands antennas would not benefit from MIMO performance. Numerical simulation of the MIMO antenna system is performed using FEKO in order to verify the design parameters. Simulation findings are confirmed by manufacturing antennas and testing in the lab.

Coupled Plasmon Modes in 2D Gold Nanoparticle Clusters and Their Effect on Local Temperature Control

Assemblies of closely separated gold nanoparticles exhibit a strong collective plasmonic response due to coupling of the plasmon modes of the individual nanostructures. In the context of self-assembly of nanoparticles, closed packed 2D clusters of spherical nanoparticles present an important composite system that promises numerous applications. The present study probes the collective plasmonic characteristics and resulting photothermal behavior of closed packed 2D Au nanoparticle clusters in order to delineate the effects of cluster size, inter-particle distance and particle size. Smaller nanoparticles (20 nm and 40 nm in diameter) that exhibit low individual scattering and high absorption were considered for their relevance to photothermal applications. In contrast to typical literature studies, the present study compares the optical response of clusters of different sizes ranging from a single nanoparticle up to large assemblies of 61 nanoparticles. Increasing the cluster size induces significant changes to the spectral position and opto-physical characteristics. Based on the model outcome, an optimal cluster size for maximum absorption per nanoparticle is also determined for enhanced photothermal effects. The effect of particle size and inter-particle distance is investigated in order to elucidate the nature of interaction in terms of near-field and far-field coupling. The photothermal effect resulting from absorption is compared for different cluster sizes and inter-particle distances considering a homogeneous water medium. A strong dependence of the steady state temperature of the nanoparticles on the cluster size, particle position in the cluster, incident light polarization and inter-particle distance provides new physical insight in local temperature control of plasmonic nanostructures.

Optical properties of silica microspheres with different functional groups.

Silica microspheres with different functional groups can be used as diagnostic material. Here, differently functionalized group (NH2-, COOH-, SiOH-, and epoxy-) silica microspheres of approximately 5μm in diameter are prepared on garnet substrates by a self-assembly method. The surface morphologies of the silica microspheres are observed by an optical microscope. The pressure generated from the glass/silica microsphere/graphite interface is measured by a resistance strain sensor as a function of an external direct current (DC) voltage. A PAX5710 IR3 polarimeter and slit beam profiler give information on the optical polarization and optical spot distance of the polarized laser beams reflected from the differently functionalized group silica microspheres. The results reveal that the relationships between the optical polarization properties, the optical spot position of the polarized laser beam, the reflectivity of the differently functionalized group silica microspheres using circularly polarized and linearly polarized laser beams, and the external pressure show different trends. The optical properties of the differently functionalized group silica microspheres are consistent with the experimental data pressure.

Photocarrier transport dynamics in lifetime and relaxation regimes of semiconductors

Understanding photogenerated carrier transport dynamics is important for optimizing the performance of various semiconductor optoelectronic devices, such as photocatalysts, solar cells, and radiation detectors. In this paper, the spatiotemporal evolution of photogenerated carriers after excitation is investigated both analytically and numerically, in order to reveal the origin of two contradictory photocarrier motion directions, i.e., separation and ambipolar transport in the semiconductors. An analytical solution of the separation distance between mean positions of photogenerated electrons and holes is derived, which shows that photocarriers will transport ambipolarly in the lifetime regime, where the carrier lifetime τ0 is larger than the dielectric relaxation time τd, and separate spontaneously in the relaxation regime, where τ0<τd. Numerical simulation verifies the analytical results and reveals rich dynamics of carrier transport near the boundary of two regimes. In the lifetime regime, the separation distance rises asymptotically to a polarization distance, while there is a transitional sub-region near the regime boundary where majority carriers go through a separating-ambipolar transformation dynamics. This phenomenon originates from two different components of the drift current. In the relaxation regime, majority carriers deplete because of a larger recombination rate in the minority carrier pulse region. Combining the analytical and numerical results, detailed photocarrier transport dynamics are obtained in the lifetime and relaxation regimes of semiconductors.

Static and dynamic tuning of surface plasmon resonance by controlling interparticle distance in arrays of Au nanoparticles

Static and dynamic tuning of plasmonic resonance in arrays of Au nanoparticles fabricated using self-assembly method on stretchable substrates was investigated. Static tuning was realized by altering the self-assembly conditions, which allowed varying average separation between Au nanoparticles and tune their collective plasmon mode with a broad wavelength range. Dynamic tuning was achieved by applying uniaxial or biaxial strain to the Au nanoparticle arrays on a stretchable substrate. Plasmonic tunability and anisotropy were demonstrated by strain-controlled stretchable substrate. Spectral shifts of collective plasmon modes with strain were found to depend on incident polarization and interparticle distance. The obtained plasmonic nanostructures can be applied as mechanically tunable plasmonic optical filters and sensors.

DFT study of the polarization behaviors of various distorted barium titanate crystals: The role of atomic displacements

A Local Density Approximation (LDA) was employed to investigate the influence of applied strains on valence charge distributions, atomic displacements, TiO (3) bond distances and the total polarizations in barium titanate (BaTiO3). Four types of various strains were imposed on perfect tetragonal BaTiO3 along the a, c, ab and abc axial directions. Electromechanical properties of BaTiO3 were evaluated in LDA framework and a good agreement with previous results was achieved. The results show that, in the cases of a, ab strains, the values of polarization are almost constant in negative strains and increased by gradual increasing of the positive strains after a sudden enhancement at about +0.1% strain. In the case of c-strain, axial oxygen and Ti atoms underwent the highest displacements and the polarization linearly increased by applied strain. The case of abc-strain, represent the both types of features. In negative abc-strain show a similar polarization behavior like c-strain case and in positive region, polarization behavior is the same as a- and ab-strain cases. In the abc-strains of −0.3% and +0.1%, an abrupt jump in total polarization curve and a small change, are observed due to abnormal atomic displacements. In the most cases a direct relation between polarization and TiO (3) bond distance was also beheld. Finally, the effects of valence charge distributions on the atomic displacements and total polarizations are studied. It is found that there is a direct relation between polarization and Valence Charge Asymmetry of 3d -orbitals.

Tuning Plasmon Resonance in Magnetoplasmonic Nanochains by Controlling Polarization and Interparticle Distance for Simple Preparation of Optical Filters.

Magnetoplasmonic Fe3O4-coated Ag nanoparticles (NPs) are assembled in large scale (18 × 18 mm2) in order to observe unique modulation of plasmonic coupling and optical tunable application via both external magnetic field and the combination of magnetic dipole and electrostatic interactions of particle-particle and particle-substrate. These large nanochains film exhibits outstanding tunability of plasmonic resonance from visible to near-infrared range by controlling the polarization angle and interparticle distance (IPD). The enormous spectral shift mainly originated from far-field rather than near-field coupling of Ag cores because of the sufficiently large separation between them in which Fe3O4 shell acts as spacer. This tunable magnetoplasmonic film can be applicable in the field of anisotropic optical waveguides, tunable optical filter, and nanoscale sensing platform.

Role of Heteronuclear Interactions in Selective H2 Formation from HCOOH Decomposition on Bimetallic Pd/M (M = Late Transition FCC Metal) Catalysts

In this study, by using spin-polarized density functional theory calculations, we have elucidated the role of heteronuclear interactions in determining the selective H2 formation from HCOOH decomposition on bimetallic Pdshell/Mcore (M = late transition FCC metal (Rh, Pt, Ir, Cu, Au, Ag)) catalysts. We found that the catalysis of HCOOH decomposition strongly depends on the variation of surface charge polarization (ligand effect) and lattice distance (strain effect), which are caused by the heteronuclear interactions between surface Pd and core M atoms. In particular, the contraction of surface Pd–Pd bond distance and the increase in electron density in surface Pd atoms in comparison to the pure Pd case are responsible for the enhancement of the selectivity to H2 formation via HCOOH decomposition. Our calculations also unraveled that the d band center location and the density of states for the d band (particularly dz2, dyz, and dxz) near the Fermi level are the important indicators that explain the impact o...

Enhanced optical magnetism for reversed optical binding forces between silicon nanoparticles in the visible region.

We perform a comprehensive numerical analysis on the optical binding forces of a multiple-resonant silicon nanodimer induced by the normal illumination of a plane wave in the visible region. The silicon nanodimer provides either repulsive or attractive forces in water while providing only attractive forces in air. The enhancement of the magnetic dipole mode is attributed to the generation of repulsive forces. The sign (attractive/repulsive) and the amplitude of the optical forces are controlled by incident polarization and separation distance between the silicon nanoparticles. These optomechanical effects demonstrate a key step toward the optical sorting and assembly of silicon nanoparticles.

Nonlinear optical cryptosystem based on joint Fresnel transform correlator under vector wave illumination

We present a nonlinear optical cryptosystem with multi-dimensional keys including phase, polarization and diffraction distance. To make full use of the degrees of freedom that optical processing offers, an elaborately designed vector wave with both a space-variant phase and locally linear polarization is generated with a common-path interferometer for illumination. The joint transform correlator in the Fresnel domain, implemented with a double optical wedge, is utilized as the encryption framework which provides an additional key known as the Fresnel diffraction distance. Two nonlinear operations imposed on the recorded joint Fresnel power distribution (JFPD) by a charge coupled device (CCD) are adopted. The first one is the division of power distribution of the reference window random function which is previously proposed by researchers and can improve the quality of the decrypted image. The second one is the recording of a hybrid JFPD using a micro-polarizers array with orthogonal and random transmissive axes attached to the CCD. Then the hybrid JFPD is further scrambled by substituting random noise for partial power distribution. The two nonlinear operations break the linearity of this cryptosystem and provide ultra security. We verify our proposal using a quick response code for noise-free recovery.

Polarization distance: a framework for modelling object detection by polarization vision systems

The discrimination of polarized light is widespread in the natural world. Its use for specific, large-field tasks, such as navigation and the detection of water bodies, has been well documented. Some species of cephalopod and crustacean have polarization receptors distributed across the whole visual field and are thought to use polarized light cues for object detection. Both object-based polarization vision systems and large field detectors rely, at least initially, on an orthogonal, two-channel receptor organization. This may increase to three-directional analysis at subsequent interneuronal levels. In object-based and some of the large-field tasks, the dominant e-vector detection axes are often aligned (through eye, head and body stabilization mechanisms) horizontally and vertically relative to the outside world. We develop Bernard and Wehner's 1977 model of polarization receptor dynamics to apply it to the detection and discrimination of polarized objects against differently polarized backgrounds. We propose a measure of 'polarization distance' (roughly analogous to 'colour distance') for estimating the discriminability of objects in polarized light, and conclude that horizontal/vertical arrays are optimally designed for detecting differences in the degree, and not the e-vector axis, of polarized light under natural conditions.

Effect of the Membrane Electrode Assemble Design on the Performance of Single Chamber Microbial Fuel Cells

Membrane electrode assemble (MEA) design is one of the crucial component of MFC. Therefore, the MEA design is critical to improving MFC's performance. In this work, effects of the presence of the cathode microporous layers and the distance between anode and cathode electrodes on MFC's performance are investigated. The experimental result indicates that the peak power density first decreases from 973 to 797 mW/m2 when decreasing the distance from 2 to 1cm, and then increases to 955 mW/m2 when further reducing the distance to 0cm. Meanwhile the ohmic resistance of the MFCs decreases from 34 to 14 and to 4.6Ω with the reduced distance. This is because that the peak power density is improved by increasing the anode potential and decreasing the ohmic loss due to the reduced distance. However, when distance reduced from 1 to 0cm, the decrease of cathode potential becomes the predominant factor. It is also found that the aerobic heterotrophic microorganism growing on the surface of both the proton exchange membrane and the anode electrode lowers the coulomb efficiency by consuming the organic substance. In addition, the presence of aerobic bacteria is the possible factor that induces the non-linear correlation between the ohmic polarization and electrodes distance.