Polar Components Research Articles

Single-shot electro-optic sampling with arbitrary terahertz polarization

With the recent development of diversity electro-optic sampling (DEOS), significant progress has been made in the range of applicability of single-shot EOS measurements, allowing broadband THz waveforms to be captured in a single shot over large temporal windows. In addition to the decrease in acquisition time compared to standard multishot data acquisition, this technique allows measurements on systems far from equilibrium with large shot-to-shot noise or with irreversible or poorly repeatable dynamics. Although DEOS has been demonstrated and verified for linearly polarized THz waveforms, we investigate the effects resulting from the presence of a secondary polarization component. This imposes new challenges for accurate waveform reconstruction, and opens the opportunity to measure out complex polarization states such as arbitrary elliptically polarized THz field. We demonstrate a single-shot diversity-electro-optic-sampling-based approach to capture both x- and y-THz fields simultaneously with a single (110)-cut EO crystal for THz polarimetry and ellipsometry over a wide range of frequencies.

First Polarimetric View of GX 349+2 with the Imaging X-Ray Polarimetry Explorer

Abstract We conducted a spectropolarimetric study of the bright Z source GX 349+2 using the Imaging X-ray Polarimetry Explorer (IXPE) observation. Our findings reveal a significant polarization degree (PD) of 1.1% ± 0.3% in the 2.0–8.0 keV energy range. Spectropolarimetric analysis was performed by modeling the source spectra with an absorbed multicolor disk component and a blackbody. This allowed us to constrain the polarization contributions from the disk and boundary/spreading layer. The results indicate that the observed polarization signal primarily originates from the disk and the spreading layer at the neutron star’s surface, rather than the boundary layer. Additionally, we detect an excess polarization component, which we attribute to either an outflow or reflection processes within the system, indicating the presence of a third component, albeit not observed in the IXPE spectra. Furthermore, energy-resolved polarization analysis in the 2.0–4.0 and 4.0–8.0 keV energy ranges hinted at a marginal increase of PD with energy and rotation of polarization angle (PA). This also pointed to an energy-dependent dominance of emission and indicated that the variation in PA with energy (∼17∘ in the 2.0–4.0 keV energy range and ∼48∘ in the 4.0–8.0 keV energy range) is likely associated with the different nonorthogonal PAs of the disk and spreading layer components, which peak at different energies.

Surfactant-free microemulsion as a fluid scaffold for the thermal stabilization of lysozyme.

Electrostatic forces supported by hydrogen-bonding (H-bonding) interactions in the presence of surfactants generally stabilize microemulsions. So, contrary to this common wisdom, developing a surfactant-free microemulsion (SFME) that is predominantly stabilized by weak but large number of H-bonding interactions would be remarkable. Herein, the formulation and characterization of an SFME comprising a hydrophobic ionic liquid (IL) and a deep eutectic solvent (DES) exhibiting high thermal stability are reported. The constituents of DES, namely, ethylene glycol (EG) and choline chloride (ChCl), served as polar and amphiphile components, respectively, and an IL, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, worked as a hydrophobic entity to form the SFME. The formation mechanism and high-temperature thermal stability of the SFME are discussed in terms of relative changes in the thickness of interfacial films, predominantly stabilizing the polar and non-polar pseudo-domains via alteration in H-bonding interactions, which is supported by computational studies. The sufficiently low interfacial energy in the SFME is exploited to thermally stabilize lysozyme (LYZ) in SFME, resulting in remarkable thermal stability of up to 150 °C, which is higher than that observed in buffer, as revealed by comparative enzyme activity at room temperature after heating. This study not only adds to the existing knowledge about the formation and stability of SFMEs but is also expected to prompt other researchers to design relatively greener IL or deep eutectic solvent (DES)-based SFMEs for various biological and other applications.

Stabilization of the Bio-Oil Organic Phase via Solvent-Assisted Hydrotreating, Part 1: Investigating the Influence of Various Solvents.

Conventional mild hydrotreatment processes of bio-oil present significant challenges of a high degree of polymerization, a low oil yield, high coke formation, and poor catalyst recovery. To address these challenges, the current study looked into investigating and enhancing the properties of raw bio-oil organic phase samples via a solvent-assisted stabilization approach using methanol (METH), ethanol (ETH), isopropyl alcohol (IPA), and ethyl ether (DME). Solvents like methanol (METH) and ethanol (ETH), which are highly polar, yielded higher oil fractions (64% and 62%, respectively) compared to less polar solvents like ethyl ether (DME) at 59%. Isopropyl alcohol (IPA), with intermediate polarity, achieved a balanced oil yield of 63%, indicating its ability to dissolve both polar and non-polar components. Moisture reduction in stabilized bio-oils followed the order IPA > ETH > METH > DME, with IPA showing the highest reduction due to its structural characteristics facilitating dehydration. Viscosity reduction varied, with IPA > ETH > DME > METH. Carbon recovery in stabilized bio-oils ranged from 65% to 75% for DME, ETH, and METH and was 71% for IPA. The heating values of stabilized bio-oils ranged from 28 to 29 MJ/kg, with IPA-stabilized bio-oil showing the highest value (29.05 ± 0.06 MJ/kg). METH demonstrated high efficiency (74.8%) in stabilizing bio-oil, attributed to its strong hydrogen-donating capability. ETH followed closely at 69.5%, indicating its comparable performance in bio-oil stabilization. With moderate efficiency (69.3%), IPA presents a balanced alternative considering its molecular structure and hydrogen solubility. In contrast, DME exhibited lower efficiency (63.6%) due to its weaker hydrogenation capability and propensity for undesired side reactions. The current study suggests that subcritical conditions up to 200 °C are adequate for METH, ETH, and IPA in bio-oil stabilization, comparable to results obtained under supercritical conditions.

Analogue supersymmetric polarized electromagnetic plasmas waves induced by a dispersive gravitational wave background

Abstract A dispersive gravitational wave background couples to electromagnetic waves in plasmas, changing its propagation properties. When the electromagnetic plasma wave are in resonance with the gravitational wave background (the phase of the two waves are equal) the dispersive gravitational waves induce a supersymmetric behavior on the transverse polarization of light. This analogue supersymmetry is in the space-time phase coordinate direction. Thus, each electromagnetic wave polarization component acts as the superpartner of the other, whereas the phase derivative of the gravitational wave is the superpotential of this analogue supersymmetry.

Exploring the Interactive Effects of γ‐Tocopherol, Ellagic Acid, and β‐Sitosterol in Iron Walnut Oil

ABSTRACTIron walnut oil is recognized for its high content of polyunsaturated fatty acids and bioactive compounds, which face significant oxidative stability challenges during storage and processing. This study investigates the antioxidant interactions among γ‐tocopherol, ellagic acid, and β‐sitosterol in iron walnut oil during the thermal oxidation, aiming to enhance its oxidative stability. The antioxidant efficacy of γ‐tocopherol, ellagic acid, and β‐sitosterol, both individually and in combination, was evaluated. γ‐Tocopherol demonstrated the strongest antioxidant activity, and its combination with ellagic acid exhibited a synergistic effect (SE), markedly enhancing the oxidative stability of iron walnut oil by reducing hydrogen peroxide formation and preserving unsaturated fatty acids, whereas β‐sitosterol exhibited limited efficacy, suggesting antagonistic interactions. The effects on fatty acid profile and polar components were analyzed via nuclear magnetic resonance (NMR) and total polar content analysis. The findings suggest that optimizing natural antioxidant combinations can effectively extend the shelf life of iron walnut oil and improve its application potential in the food industry, aligning with the demand for clean‐label and sustainable products.Practical Application: The study provides valuable insights for food industry professionals working with polyunsaturated fatty acid (PUFA)‐rich oils. By demonstrating that γ‐tocopherol and ellagic acid significantly enhance the oxidative stability of iron walnut oil, the research offers practical guidance for formulating walnut oil‐based products with extended shelf life. These findings can directly inform the development of natural antioxidant systems in food preservation, aligning with consumer demands for clean‐label and sustainable products. Researchers can use this information to optimize antioxidant combinations in various food formulations, potentially reducing waste and improving the nutritional profile of food products. The study also highlights the importance of careful antioxidant selection to avoid antagonistic interactions, which is crucial for the industrial application of health‐focused products.

Fast polarized neutron imaging for estimating screening current in superconducting multifilamentary YBCO tape

In this paper we showcase the strengths of polarized neutron imaging as a magnetic imaging technique through a case study on field-cooled multifilamentary YBCO tape carrying a transport current while containing a trapped magnetic field. The measurements were done at J-PARC's RADEN beamline, and the analysis is based on a radiograph of a single polarization component, to showcase the analysis potential for fast measurements with short acquisition time. Regions of internal damage are easily and accurately identified as the technique probes the internal magnetic field of the sample directly. Quantitative measurements of the integrated field strength in various regions are acquired using time-of-flight information. Finally, the strength of the screening currents in each filament of the superconductor are estimated by simulating an experiment with a model sample and comparing it to data. With this, we show that polarized neutron imaging is not only a useful tool for investigating magnetic structures but also for investigating currents.

Surface energy governs the electrical conductivity of polymer-matrix composites

The electrical conductivity (σ) of composites varies significantly depending on matrix polymer even when identical conductive fillers are employed. Here we elucidate the governing parameter of the filler–polymer interaction and σ of composites. The σ of the AgPolymer composites, synthesized by dispersing silver flakes (AgFLs) in different elastomer, thermoplastic, or thermoset polymers, varies by more than an order of magnitude in spite of the identical filler concentration (35 vol%). Although elastic modulus (E, related to the bond stiffness) and fracture energy (G, corresponding to the energy absorbed during bond cleavage) offer some insights, they are insufficient to fully elucidate the filler–polymer interaction. The excessive interaction between the AgFLs and poly-vinyl alcohol leads to the deviation from the σ-E and σ-G relationships of other AgPolymer composites. Surprisingly, the surface energy (γ) of composites (20.4–41.7 mJ m−2), obtained by the van Oss-Good model, is found to govern the σ of composites (1,598.4–36,508.0 S cm−1) without an outlier. The dispersive and polar components of the γ of AgFLs and polymer determine the filler–polymer interaction, AgFL dispersion, and σ of composites. The σ can also be predicted using the intrinsic γ of AgFLs and polymers, before synthesizing composites, which is useful for the future composite design.

Optical solitons for the dispersive concatenation model with polarization mode dispersion in presence of multiplicative white noise

Abstract The current work focuses on the dispersive concatenation model, which is a framework used to describe the interaction of multiple dispersive effects. In this study, polarization mode dispersion is analyzed in the presence of multiplicative white noise, which affects both polarization components of the system. Using the $$F$$ F -expansion method, a comprehensive analysis is carried out, revealing a broad spectrum of optical solitons, including various forms such as bright, dark, and singular solitons, as well as complexiton solutions. The investigation shows that despite the presence of white noise, its influence remains restricted primarily to the phase components of the two polarized modes, without significantly altering the amplitude or the fundamental nature of the solitons. This indicates that the soliton structures are robust against the noise, preserving their shape and energy profiles while experiencing phase shifts.

Preparation and study of quartz yarn with good permeability by controlling the content of polar components in wetting agent

Preparation and study of quartz yarn with good permeability by controlling the content of polar components in wetting agent

A quantitative assessment of the influence of voltage on the formation of oxide layers on the surface of titanium by anodization.

A quantitative assessment of the influence of voltage on the formation of oxide layers on the surface of titanium by anodization.

Investigation of the effect of DBD plasma treatment on the surface properties of polylactic acid layers prepared with different mass percentage of polylactic acid/chloroform solution

AbstractPolylactic acid (PLA) is a biodegradable polymer that has gained prominence as a functional material, particularly in the form of thin films used in industries like food packaging. These films are typically applied by melting, but this method is unsuitable for heat‐sensitive surfaces. This study investigates the use of a plasma dielectric barrier discharge system (DBD) to modify PLA films prepared from a PLA–chloroform solution at 5, 10, and 15 mass percentage concentrations (% w/v). To evaluate the surface properties of the PLA films, contact angle measurements, surface energy assessments, atomic force microscopy (AFM), and Fourier‐transform infrared spectroscopy (FTIR) were conducted. Contact angle measurements revealed a dramatic decrease in the contact angle, from 75 ± 0.18° for untreated films to 28.7° for plasma‐treated films at 15% PLA concentration. FTIR analysis confirmed an increase in the intensity of some peaks related to polar oxygenated functional groups, particularly hydroxyl (‐OH) and carbonyl (C=O) groups. Atomic force microscopy analysis reveals a needle‐shaped surface morphology after plasma treating, that is, increased roughness and surface area. Surface energy analysis showed a reduction in the dispersive component of surface energy but an overall increase in total surface energy; specifically, the polar component of surface energy increased by 45% at 15% PLA concentration compared to untreated films. When comparing the results obtained in the present study with those from a recent work that used a non‐polar solvent (toluene), the polarity of the solvent could be a determining factor in the polymer films with different concentration obtained through solution deposition, which is affected by plasma. This could serve as a starting point for further investigations in this area. Overall, plasma treatment proved effective in modifying PLA films on heat‐sensitive substrates, enhancing hydrophilicity, particularly at higher PLA solution concentrations prior to casting a thin film.Highlights PLA–chloroform solutions with different concentrations were prepared. PLA–chloroform films were spin‐coated and treated with DBD plasma. Contact angle, surface energy measurement, AFM, and FTIR analysis were conducted. PLA films with higher concentration were more impacted by plasma treatment. Concentration and solvents polarity impact the hydrophilicity and roughness of treated PLA films.

A Low-Profile Dual-Polarized Transmitarray with Enhanced Gain and Beam Steering at Ku Band

A low profile dual polarized transmitarray antenna, made of three identical layers, is proposed in this paper for Ku-band applications. The transmitarray comprises 22 × 22 symmetrical unit cells. A 3-bit phase compensation layer with less than αT = 1.3 dB transmission loss and 2π transmission phase coverage for both linear polarized components at the central frequency f0 = 12 GHz is designed. Moreover, for an incidence angle θ = 30°, the unit cell transmission loss is less than 2 dB; the transmission phase is close to the transmission phase at zero incidence angle θ = 0°. The fabricated transmitarray exhibits a measured peak gain of Gm0 = 21 dB at the frequency f0 = 12 GHz. The corresponding measured 1 dB gain bandwidth is BWg = 10.8% (11.1–12.4 GHz). The measured peak side lobe levels are SLL0 = −20.8 dB at f0 = 12 GHz. The transmitarray antenna can be used for beam steering up to an angle of γmax = ±30° with a measured scan loss △GMSL1 = 2.73 dB at f1 = 12.4 GHz.

Control of ferroelectric polarization in BiFeO3 bilayer films through interface engineering

Predetermining the as-grown polarization of ferroelectric thin films is essential to integrate their reliable properties into electronic devices. However, studies have so far focused mainly on the control of the polarization state of a single ferroelectric layer. Here we report a strategy for the artificial modulation of pristine polarization in BiFeO3 bilayer films. We have fabricated multilayers of BiFeO3/SrTiO3/BiFeO3 on single-crystalline SrTiO3 (001) substrates. It is found that the out-of-plane polarization components of the BiFeO3 bilayer can be controlled by modifying the surface terminations of SrTiO3 interlayer and SrTiO3 substrate. Using aberration-corrected scanning transmission electron microscopy, we directly visualize the head-to-head and tail-to-tail polarization configurations formed by the BiFeO3 bilayers. Polar discontinuity at the ferroelectric/non-ferroelectric interface is the reason for tuning the orientation of electrical polarization. Our work provides an effective route to design fascinating ferroelectric multilayers with well-defined polarization direction.

All-optical polarization-filtered subwavelength imaging in microwave regime via atom-based polarization holography

Polarization imaging is essential to reveal rich information of the vectorial nature of microwaves. However, selective imaging of specific polarization components with subwavelength resolution remains challenging. Here, we propose atom-based polarization holography for all-optical polarization-filtered subwavelength imaging in microwave regime. A kind of atomic polarization holograms is recorded through two-photon excited anisotropy in a four-level quantum system and its diffraction properties are characterized using Jones theory combined with optical Bloch equation. It is found that the polarization information of microwaves can be actively manipulated to holographic diffracted light fields. Moreover, polarization imaging of atom-based polarization holography with a spatial resolution of one-fortieth wavelength (λ/40) has been realized experimentally through microwave-to-optical conversion. The function of polarization filtering is demonstrated by optical holographic diffraction and the microwave component with specific polarization state can be selectively imaged from superimposed polarized microwaves. Our work is expected to enable applications in polarization filtering and subwavelength imaging.

Atmospheric plasma treatment for improved epoxy coating performance on aluminium alloys

Achieving strong adhesion of polymer coatings like epoxy, acrylic, and polyurethane to aluminium surfaces is a crucial focus in materials research, given its importance across the automotive, aerospace, marine, and construction sectors. Current adhesion-promoting surface treatments like anodizing, electropolishing, phosphate and chromate conversion coatings are environmentally problematic due to their chemical processes, necessitating the development of alternative solutions. With the goal of enhancing coating performance on aluminium alloys, we introduce atmospheric pressure plasma jet technology to improve the adhesion, mechanical performance, and corrosion resistance of epoxy coatings. This study investigates the impact of atmospheric pressure plasma treatment on the adhesion, scratch resistance, and corrosion resistance of graphene-reinforced epoxy (EP/G) composite coatings applied to aerospace aluminium alloy AA7075. Contact angle measurements, FTIR spectroscopy, and surface free energy (SFE) analysis were used to characterize the resulting surfaces. Test specimens were plasma-treated before applying the coating. The impact of the plasma treatment on surface wettability was studied by analyzing its effect on the dispersive ( γ L D ) and specific polar ( γ L S P ) components of surface free energy. The removal of surface contaminants and weak boundary layers by plasma treatment increased surface reactivity, directly leading to a significant increase in surface free energy (SFE) from 43.49 mJm 2 to 142.34 mJm 2 . This improved the surface wettability. Potentiodynamic polarization analysis revealed that the composite coating's oxidation resistance was significantly enhanced by the surface cleaning process using ionized argon ions prior to coating. This was evidenced by a shift in the E corr value from – 1.28 V to 0.31 V. Further, supporting the protective effect of coatings, electrochemical impedance spectroscopy (EIS) results indicated superior corrosion resistance for EP/G coating on plasma treated AA7075 than coating on untreated samples.

Recent advances in photoelectric methods application for cooking oil quality and safety evaluation: a review.

Cooking oil is used daily in consumed food and culinary applications; therefore, its safety and quality are very important. Notably, susceptibility to contamination at each processing stage poses threats to living organisms. This review discusses the parameters of oil quality, as well as the role of the various non-destructive photoelectric techniques with respect to its quality and safety, including near-infrared spectroscopy (NIR), mid-infrared spectroscopy, Fourier transform near-infrared spectroscopy, Raman spectroscopy and fluorescence spectroscopy. Data on cooking oil quality, such as values of the following parameters, notably peroxides, thiobarbituric acid, anisidine, iodine, trans-fat and fatty acid profile, carbonyl compounds, adulteration and total polar components, are also demonstrated. Photoelectric methods are rapid and efficient tools for the preliminary screening of cooking oil when aiming to determine its quality before its entry into the food chain. Primarily, NIR has been used to predict most of the cooking oil safety and quality parameters, and thus is considered as the most convenient non-destructive method to be recommended. Accordingly, deep insight into state-of-the-art photoelectric/spectral technologies and the varieties of techniques available provides an opportunity to detect and predict the safety parameters of products prior to their processing and distribution. In this review, we highlight these perspectives with particular emphasis on the cooking oil. © 2025 Society of Chemical Industry.

Real-time automatic polarization control based on golden section search and proportional endless reset-free control action

We propose and experimentally demonstrate a real-time automatic polarization control scheme for fiber-optic systems based on golden section search (GSS) and proportional endless reset-free (PE-RF) control action. In the proposed method, we separate the orthogonal components of the incoming state of polarization of light and use one of the polarization components to generate a feedback signal such that the power in the other component is maximized. The feedback signal is applied to waveplates of an electronic polarization controller for which the required voltage signals are derived by the application of GSS and PE-RF control algorithms, implemented on an Arduino Uno R3 microcontroller. Our proposed method is simple, cost-effective, and has a fast response to mitigate polarization fluctuations in optical fiber links. We demonstrate this by maintaining stable polarization operation of binary and 4-PAM optical links consisting of 50 km optical fiber operating at 1550 nm. The proposed method maintains a Q-factor to within ±0.5dBm with excellent eye opening over 100 min of continuous operation.

The effect of diethyl ether on interfacial tension and oil swelling in crude oil-brine system

Solvent injection, a proven method in enhanced oil recovery (EOR), has shown substantial enhancements in oil recovery compared to conventional waterflooding methods. Interfacial tension (IFT) is a critical factor that determines the amount of residual oil in a reservoir and the distribution of fluids within it. This highlights the importance of accurately understanding the interactions at the oil-brine interface. This study marks the first investigation into the effects of Diethyl Ether (DEE) on both the IFT within an oil-brine system and the oil swelling under different salinity and temperature conditions, employing the pendant drop method. The experimental findings demonstrate that the utilization of DEE significantly diminishes the IFT between oil and brine. As temperature and salinity levels rise, the IFT of the oil-brine-DEE system decreases. Nonetheless, this investigation underscores the importance of salinity levels in achieving the most substantial reduction in IFT. The optimal performance of DEE occurs in the seawater (SW) sample at 70 °C, resulting in the lowest IFT at approximately 2 mN/m ( 90% reduction) compared to the initial value. Furthermore, the greatest oil swelling was observed in SW compared to all other samples. This remarkable performance is attributed to the synergistic effects of DEE and ions present in the aqueous phase. Additionally, the migration of polar components such as asphaltene molecules to the interface of the oil-brine system should be considered for achieving the highest reduction in IFT. The findings of this study have the potential to advance the understanding of the underlying mechanisms involved in water-soluble solvent EOR technologies.

Exploring the mode conversion of a vector vortex beam in second-harmonic generation using a periodically poled nonlinear photonic KTiOPO4 crystal

The nonlinear interactions between structured beams with spatially varying polarization and matter extend the boundaries of fundamental nonlinear optics, opening new avenues for applications across various fields. In this work, the second-harmonic generation (SHG) of vector beams with two orthogonal polarization components of vortices in a periodically poled crystal (PPC) is demonstrated both theoretically and experimentally. Potassium titanyl phosphate KTiOPO4 (KTP) is chosen as the PPC for its excellent nonlinear-optical properties. Notably, for a given vector light field, adjusting the initial phase of the vector beam allows for the varying outputs of SHG. In addition, SHG outputs with one, two, or three vortices are achieved by rotating a polarizer to modulate the fundamental light, and the proportion weights of the three vortex terms within the SHG are dependent on the rotating angles of the polarizer. Our findings provide a foundational understanding and offer new insights into the study of full-field selection rules in specific nonlinear processes within superlattices.