Dispersion Properties Research Articles

Features of Planar Localization of Acoustic Emission Sources via the Inglada’s Triangulation Algorithm

This paper presents a methodology for enhancing the efficiency of acoustic emission (AE) source detection during planar localization using the Inglada’s algorithm. The study analyzes the main factors affecting the accuracy of AE source localization when using a standard planar localization approach. These factors include the threshold-based method of determining the signal registration time by AE sensors, which is based on detecting the moment when the rising wavefront voltage exceeds the discrimination threshold (uth), the signal sampling frequency (fd), and the influence of the medium’s dispersion properties on the attenuation of signal amplitude and wave propagation speed. To reduce the impact of these factors on the localization accuracy of AE sources, a novel methodology is proposed based on the use of correlation dependencies of AE pulse propagation speed on the amplitude of the recorded signals, as well as on accounting for the delay in the registration time of AE pulses during threshold detection. A series of preliminary experiments was conducted to implement the proposed methodology, where AE pulses were generated using an electronic simulator with a maximum amplitude level of um = 45—90 dB. The position of the AE pulse source varied in the range of 150 to 700 mm relative to the receiving sensors of the antenna array. As a result of applying the developed methodology, the probability of AE source detection increased to p = 0,71, compared to p = 0,36 when using the standard approach.

Impact of organic contaminant viscosity and cation hydrated radius on the rheological properties of sodium-bentonite: experimental and numerical investigations.

Soil contamination by organic and hazardous substances is a critical environmental issue, particularly in developing countries. This study investigates the limitations of double-layer theory for bentonite-organic contaminant interactions through experimental and numerical analysis. Using NaCl and KCl as salts and acetone, isopropyl alcohol, and glycerol as organic contaminants, the research explores the rheological properties of Na-bentonite dispersions. The double-layer theory, particularly Stern's model, has limitations in accurately representing the interaction between bentonite and organic contaminants. The research aims to validate the double-layer equations and investigate the impact of viscosity and cation hydrated radius on the rheological properties of Na-bentonite. The novelty lies in introducing a range of viscosities into the pore fluid to challenge existing double-layer equations. Numerical calculations based on double-layer theory were used to analyze the total interaction energy. The study found that without salt, bentonite showed similar rheological behavior in acetone and alcohol but higher yield stress in glycerol. NaCl up to 0.1M increased yield stress, while 0.5M reduced it. KCl had a more pronounced effect on rheological properties than NaCl, highlighting the importance of cation hydrated radius. In soil-organic mixtures, lower viscosity organic chemicals increased yield stress. Despite similar dielectric constants, acetone showed higher yield stress than glycerol at lower concentrations, but at higher concentrations, dielectric constant differences became dominant. The study confirms the limitations of double-layer theory in bentonite-organic contaminant interactions, particularly regarding pore fluid viscosity, though it remains reliable at high contaminant concentrations.

One Stone for Multiple Birds: Copolymer with Multifunctional Groups Boosts the Cycling Stability of Lithium Cobalt Oxide Cathodes at 4.5 V.

High-voltage LiCoO2 is a promising cathode material for ultrahigh-energy lithium-ion batteries, particularly in the commercialization of 5G technology. However, achieving long-term operational stability remains a significant challenge. Herein, a quaterpolymer additive with multiple functional groups is introduced to enhance the electrochemical performance of LiCoO2 cathode at 4.5 V. The capacity remains 96% after 100 cycles at room temperature and 94.4% after 50 cycles even at 45 °C. The sulfonate and ester groups of the quaterpolymer additive serve as lithium carriers, providing high voltage resistance and fast ionic conductivity with increased lithium-ion diffusion coefficients during the charge/discharge processes. The incorporation of a quaterpolymer additive also improves the dispersion properties and peel strength of the LiCoO2 cathodes. The coordination between the sulfonate groups and Li+ as well as the amine-based derivatives and Lewis acid of PF5 is expected to disrupt the Li+ solvation shell and deactivate the PF5 reactivity, therefore suppressing electrolyte decompositions. Furthermore, the superior interactions between sulfate ester (O atoms)/amide (N atoms) groups of copolymer additive and superficial cobalt atoms of LiCoO2 provide a compensating charge to Co, inhibiting the surface cobalt dissolution, irreversible oxygen redox reaction, and the detrimental LiCoO2 phase transition from O3 to H1-3. The use of a tiny amount of polymer additive presents an effective approach to stabilizing high-voltage LiCoO2, offering valuable insights for the design of high-energy battery materials.

Deep knowledge transfer powered ultrasonic guided wave damage monitoring under incomplete database scenarios: Theories, applications and challenges

Abstract Ultrasonic guided waves can travel long distances within the detected structures, which is of great significance for monitoring large complex engineering systems. However, the multimodal and dispersive properties of the specific research object making this promising whole structure monitoring difficult to interpret the signal mathematically and physically. With the development and maturity of deep learning and big data mining technologies, many scholars have noticed artificial intelligence algorithms such as deep learning can provide a new tool in ultrasonic guided wave signal processing, avoiding the mechanism analysis difficulties in the application of ultrasonic guided wave. But the integrity of structural state data sets has become a new pain point in engineering applications under this new approach, and how to apply the knowledge obtained from the existing data set to different but related fields through knowledge transfer in such cases begin to attract the attention of scholars and engineers. Although several systematic and valuable review articles on data-driven ultrasonic guided wave monitoring methods have been published, they only summarized relevant studies from the perspective of data-driven algorithms, ignoring the knowledge transfer process in practical application scenarios, and the intelligent ultrasonic guided wave monitoring methods based on knowledge transfer of incomplete sets are still lacking a comprehensive review. This paper focuses on the ultrasonic guided wave transfer monitoring technology when the training sample is missing, explores the feature correlation between samples in different domains, improves the transfer ability of the structural monitoring model under different conditions, and analyzes the ultrasonic guided wave intelligent monitoring methods for structural state under different sample missing conditions from three aspects: semi-supervised monitoring, multi-task transfer and cross-structure transfer. It is also expected to provide a new method and approach to solve the condition monitoring problems in other complex scenarios.

Length effects of PE-based selvage fibers on fresh, fiber dispersion, and tensile properties of engineered cementitious composites

Due to high cost and embodied energy of synthetic fibers, their use in engineered cementitious composites (ECCs) is a barrier against the practical applications of ECC. This study investigated the length effects of fibers obtained from polyethylene-based selvage, the edges of woven fabrics that are normally discarded, on fresh, fiber dispersion, and tensile properties of ECC. Three ECC mixtures were designed with selvage fibers with lengths of 5, 10, and 15 mm. Mini-slump and mechanical tests were performed, and fiber dispersion was evaluated. Test results showed that flowability increased as the length of selvage fibers decreased. On the other hand, compressive strength, tensile strength, and tensile strain capacity increased as the length of selvage fibers increased. It was observed that the length of selvage fibers had little influence on fiber dispersion. The tensile properties of F-5 mixture, showing minimum performance, were superior to those of recycled fiber-reinforced ECCs.

Preparation and Performance of ATH-OPC-PEG Bilayer Microcapsules Based on Targeted Flame Retardation Against Spontaneous Coal Combustion

ABSTRACT In order to solve the problem of spontaneous combustion of coal in the air-mining area, ATH-OPC-PEG double-layer flame retardant microcapsules were prepared. The environmentally friendly flame retardant aluminum hydroxide (ATH) was selected as the core material of the microcapsules. Due to the high action temperature and late action time of ATH, sodium alginate-modified melamine-melamine resin was used as the first layer of shell material of microcapsules to coat ATH. Then molten polyethylene glycol (PEG) mixed with the environmentally friendly strong antioxidant proanthocyanidin (OPC) was used as the second layer of shell material for the secondary coating of microcapsules. Providing antioxidant properties to microcapsules. The surface morphology, dispersion, encapsulation, pyrolysis, and flame retardant properties of the microcapsules were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analyzer (TG), and cone calorimeter. On this basis, the microcapsules were mechanically mixed with coal samples, and four coal samples were prepared for combustion tests. The results showed that ATH-OPC-PEG microcapsules prolonged the water locking time and increased the TGA by 1.162%. According to the cone calorimeter analysis, the CO and CO2 release rates of microcapsule-treated coal were reduced by 27.90% and 13.98% compared with that of pure coal. This study provides directional solution ideas for solving different stages of spontaneous combustion of coal in the mining area, and enriches the technical means of fire prevention and extinguishing.

Quasi‐Bound States in the Continuum on Dislocated Bilayer Metal Gratings for Spatiotemporal Vortex Pulse Generation

AbstractSpatiotemporal vortex pulses (STVPs) with transverse orbital angular momentum (OAM) have recently stimulated great interest, influencing wide disciplines from classical to quantum optics. However, generating sophisticated STVPs in high‐efficiency and compact systems remains a challenge. This work outlines an ultra‐compact metasurface approach to efficiently generate STVPs through the coupling of free‐space plane waves with a quasi‐bound state in the continuum (quasi‐BIC). The approach leverages external excitation of the quasi‐BIC at the Γ‐point by slightly dislocating two sub‐layer gratings to break the mirror symmetries. This operation converts the incident wave into a unidirectional surface mode and induces a Fano resonance, resulting in STVPs in the frequency‐momentum domain. The method is demonstrated experimentally with a meta‐grating to produce an electromagnetic (EM) STVP with a topological charge of l = −1 with high fidelity and use the set‐up to unravel the hitherto unexplored diffraction and dispersive properties of near‐field STVPs. The present work can be extended from the microwave to the visible light regime by simply scaling the metasurface, and allowing high‐order OAM generation through cascaded elements, thereby paving a robust way to build up ultra‐compact STVP multiplexing devices for future applications.

Sodium dodecyl sulfate‐coated silver nanoparticles accelerate antimicrobial potentials by targeting amphiphilic membranes

AbstractCompelling concerns about antimicrobial resistance and the emergence of multidrug‐resistant pathogens call for novel strategies to address these challenges. Nanoparticles show promising antimicrobial activities; however, their actions are hindered primarily by the bacterial hydrophilic–hydrophobic barrier. To overcome this, we developed a method of electrochemically anchoring sodium dodecyl sulfate (SDS) coatings onto silver nanoparticles (AgNPs), resulting in improved antimicrobial potency. We then investigated the antimicrobial mechanisms and developed therapeutic applications. We demonstrated SDS‐coated AgNPs with anomalous dispersive properties capable of dispersing in both polar and nonpolar solvents and, further, detected significantly higher bacteriostatic and bactericidal effects compared to silver ions (Ag+). Cellular assays suggested multipotent disruptions targeting the bacterial membrane, evidenced by increasing lactate dehydrogenase, protein and sugar leakage, and consistent with results from the transcriptomic analysis. Notably, the amphiphilic characteristics of the AgNPs maintained robust antibacterial activities for a year at various temperatures, indicating long‐term efficacy as a potential disinfectant. In a murine model, the AgNPs showed considerable biocompatibility and could alleviate fatal Salmonella infections. Collectively, by gaining amphiphilic properties from SDS, we offer novel AgNPs against bacterial infections combined with long‐term and cost‐effective strategies.

Leaf-Shaped Nanostrip Fed Graphene Plasmonic Nano-Antenna for Optical Near-Field Applications

The manuscript investigates the leaf-shaped nanostrip-fed graphene plasmonic nanopatch on a silicon dioxide surface for optical near-field applications. The dispersion properties of graphene and silicon dioxide are demonstrated through Drude and Lorentz modeling to examine the suitability of the materials for the plasmonic nano-antenna design. The nano-antenna parameters TSUB (substrate thickness), W (width of the nanostrip feed line) and RL(nano-antenna size) are adjusted to modify the plasmonic resonance frequency from 7.9 THz to 40.9 THz. The proposed leaf-shaped nanostrip-fed graphene plasmonic nanopatch exhibits a reflection of -43.27 dB at 36 THz with a gain of 8.19 dB at TSUB =125 nm, W = 40 nm and RL = 50 nm.

New Approaches to Determining the D/H Ratio in Aqueous Media Based on Diffuse Laser Light Scattering for Promising Application in Deuterium-Depleted Water Analysis in Antitumor Therapy

The development of affordable and reliable methods for quantitative determination of stable atomic nuclei in aqueous solutions and adjuvant agents used in tumor chemotherapy is an important task in modern pharmaceutical chemistry. This work quantified the deuterium/prothium isotope ratio in aqueous solutions through an original two-dimensional diffuse laser scattering (2D-DLS) software and hardware system based on chemometric processing of discrete interference patterns (dynamic speckle patterns). For this purpose, 10 mathematical descriptors (di), similar to QSAR descriptors, were used. Correlation analysis of bivariate “log di—D/H” plots shows an individual set of multi-descriptors for a given sample with a given D/H ratio (ppm). A diagnostic sign (DS) of differentiation was established: the samples were considered homeomorphic if 6 out of 10 descriptors differed by less than 15% (n ≥ 180). The analytical range (r = 0.987) between the upper (D/H ≤ 2 ppm) and lower (D/H = 180 ppm) limits for the quantification of stable hydrogen nuclei in water and aqueous solutions were established. Using the Spirotox method, a «safe zone» for protozoan survival was determined between 50 and 130 ppm D/H. Here, we discuss the dispersive (DLS, LALLS) and optical properties (refractive index, optical rotation angle) of the solutions with different D/H ratios that define the diffuse laser radiation due to surface density inhomogeneities. The obtained findings may pave the way for the future use of a portable, in situ diffuse laser light scattering instrument to determine deuterium in water and aqueous adjuvants.

Ti3C2Tx and Mo2TiC2Tx MXenes as additives in synovial fluids - towards an enhanced biotribological performance of 3D-printed implants

Synovial joints, critical for limb biomechanics, rely on sophisticated lubrication systems to minimize wear. Disruptions, whether from injury or disease, often necessitate joint replacements. While additive manufacturing offers personalized implants, ensuring wear resistance remains a challenge. This study delves into the potential of Ti3C2Tx and Mo2TiC2Tx nanosheets in mitigating wear of additively manufactured cobalt-chromium tungsten alloy substrates when incorporated as additives into synovial fluid. The colloidal solutions demonstrate an excellent stability, a crucial factor for reproducible assays and potential clinical applicability. Analysis of contact angles and surface tensions reveals MXene-induced alterations in substrate wettability, while maintaining their general hydrophilic character. Viscosity analysis indicates that MXene addition reduces the dynamic viscosity, particularly at higher concentrations above 5 mg/mL, thus enhancing dispersion and lubrication properties. Friction and wear tests demonstrate a dependency on the MXene concentration, while Ti3C2Tx exhibits stable friction coefficients and up to 77 % wear reduction at 5 mg/mL, which was attributed to the formation of a wear-protecting tribo-film (amorphous carbon and MXene nano-sheets). Our findings suggest that Ti3C2Tx, when supplied in favorable concentrations, holds promise for reducing wear in biotribological applications, offering avenues for future research into optimizing MXene utilization in load-bearing joint replacements and other biomedical devices.

Waste management of straw to manufacture biochar: An alternative reinforcing filler for natural rubber biocomposites

To achieve climate neutrality, alternative processes and materials should be proposed to replace those currently in use, which excessively burden the environment. Fossil fuels are non-renewable, and their resources are slowly being depleted, leading to increased prices.The aim of this work was to determine the potential of using agro-industrial residues in the form of oat straw for the production of biochar and its utilization as a filler in natural rubber biocomposites. The process of pyrolysis of plant material was used to obtain biochar with a high carbon content and a characteristic structure, which can affect selected rubber properties. The influence of the applied temperature of the pyrolysis process on the properties of the filler was determined. In this work, analysis techniques were used to enable the evaluation of both filler activity and specific properties of the final vulcanizates. The course of straw pyrolysis process, the carbon content in the fillers, and the size distribution of the bio-additive were examined. The structural, morphological, dispersion, processing, and functional properties of the compositions were examined. The reference in assessing the impact of the produced bio-additive on the properties of the product were composites filled with a commercial carbon black.The conducted research proved that the pyrolysis of straw at a temperature of 600°C was as effective as that carried out at a higher temperature, with comparable weight loss for both samples. The increase in torque was the highest in the case of biochar samples (torque gain 4,4-6,5 dNm), indicating greater intensity of the cross-linking process after the use of this type of additive. This was also confirmed by differential scanning calorimetry. Moreover, the obtained biocomposites were characterized by much higher strength parameters (tensile strength 18,3-21,3MPa) than conventional composites. Unfortunately, vulcanizates containing biochar as a filler exhibited poor resistance to thermo-oxidative aging (aging factor 0,24-0,54).

Observation of spatiotemporal dynamics for topological surface states with on-demand dispersion

Dispersion management in guided wave optics is of vital importance for various applications. Topological photonics opens new horizons for manipulating unidirectional guided waves utilizing edge states. However, the experimental observation of spatiotemporal dynamics for guided waves with on-demand dispersion in topological photonic crystal is an important issue awaiting exploitation. Herein, we experimentally investigate the spatiotemporal properties of topological surface states with on-demand dispersion, where they are supported by a truncated valley photonic crystal with surface modulation. We observe the electromagnetic dynamics of surface states with typical dispersions, where dynamical trapping of an electromagnetic pulse mediated by the unidirectional surface state with flat dispersion and backward beam routing using reversed dispersion properties are achieved in photonic crystal slabs. Both numerical and experimental results substantiate the ultimate dispersion management for topological surface states, which could pave new ways for the manipulation of electromagnetic waves on the surface of photonic devices.

Modelling of EM Wave Propagation in Distorted Conventional Optical Fiber to Multilayer Hollow Bragg Fiber

Present investigation deals with the electromagnetic (EM) wave propagation through the asymmetrical (distorted) conventional optical fiber and extended the investigation for the distorted multilayered hollow Bragg Fiber. For this purposed theoretical and mathematical are well connected to investigate and further discuss the wave propagation through such distorted structure so that further many useful parameters like optical power, different losses, dispersion analysis, etc. can be computed easily by the researchers in the same area. In present study, the dispersion properties of an optical fiber with a little one-sided flattening are modelled using a straightforward mathematical approach that relies on coordinate transformation. In order to derive the modal eigenvalue equation, we provide the boundary condition under a weak guiding condition and choose new orthogonal coordinates that are suitable for the suggested waveguide construction. Further, a distorted Bragg fiber with a little flattened distortion is anticipated to have dispersion characteristics by comparing the fields at different boundaries.

Justification of the Benjamin–Ono equation as an internal water waves model

AbstractIn this paper, we give the first rigorous justification of the Benjamin-Ono equation: $$\begin{aligned} \hspace{3cm} \partial _t \zeta + (1 - \frac{\gamma }{2}\sqrt{\mu }|\textrm{D}|)\partial _x \zeta + \frac{3{\varepsilon }}{2}\zeta \partial _x\zeta =0, \hspace{2cm} \text {(BO)} \end{aligned}$$ ∂ t ζ + ( 1 - γ 2 μ | D | ) ∂ x ζ + 3 ε 2 ζ ∂ x ζ = 0 , ( BO ) as an internal water wave model on the physical time scale. Here, $${\varepsilon }$$ ε is a small parameter measuring the weak nonlinearity of the waves, $$\mu $$ μ is the shallowness parameter, and $$\gamma \in (0,1)$$ γ ∈ ( 0 , 1 ) is the ratio between the densities of the two fluids. To be precise, we first prove the existence of a solution to the internal water wave equations for a two-layer fluid with surface tension, where one layer is of shallow depth and the other is of infinite depth. The existence time is of order $${\mathcal {O}}(\frac{1}{{\varepsilon }})$$ O ( 1 ε ) for a small amount of surface tension such that $${\varepsilon }^2 \le \textrm{bo}^{-1} $$ ε 2 ≤ bo - 1 where $$\textrm{bo}$$ bo is the Bond number. Then, we show that these solutions are close, on the same time scale, to the solutions of the BO equation with a precision of order $${\mathcal {O}}(\mu + \textrm{bo}^{-1})$$ O ( μ + bo - 1 ) . In addition, we provide the justification of new equations with improved dispersive properties, the Benjamin equation, and the Intermediate Long Wave (ILW) equation in the deep-water limit.The long-time well-posedness of the two-layer fluid problem was first studied by Lannes [Arch. Ration. Mech. Anal., 208(2):481-567, 2013] in the case where both fluids have finite depth. Here, we adapt this work to the case where one of the fluid domains is of finite depth, and the other one is of infinite depth. The novelties of the proof are related to the geometry of the problem, where the difference in domains alters the functional setting for the Dirichlet-Neumann operators involved. In particular, we study the various compositions of these operators that require a refined symbolic analysis of the Dirichlet-Neumann operator on infinite depth and derive new pseudo-differential estimates that might be of independent interest.

Fiber-integrated hybrid achromatic microlenses by combined femtosecond laser 3D printing

Compact achromats for visible wavelengths are crucial for miniaturized and lightweight full-color endoscopes. Emerging femtosecond laser 3D printing technology offers new possibilities for enhancing the optical performance of miniature imaging lenses on fibers. In this work, we combine refractive and diffractive elements with complementary dispersive properties to create thin, high-performance hybrid achromatic lenses within the visible spectrum, avoiding the use of different optical materials. Using a fiber-integrated hybrid achromatic lens array, clear images are captured across different wavelengths. The fabrication process is carried out using femtosecond laser direct writing (DLW) assisted by femtosecond projection lithography based on a digital micromirror device (DMD). Our work is expected to significantly contribute to the advancement of integrated and miniaturized biomedical imaging devices.

Fluorescent core-shell SiO2@COF composite for ultra-sensitive detection of cysteine and homocysteine.

To improve the fluorescence properties of covalent organic framework(COF) materials, core-shell SiO2@COF compositewas prepared, in which SiO2 was used as inner substrate, and BMTH (2,5-bis (2-methoxyethoxy) p-phenylhydrazide) and HB (2-hydroxy-1,3,5-phenyltrialdehyde) acted as precursors to construct COFBMTH-HB layer on the surface of SiO2. Compared with COFBMTH-HB, SiO2@COFBMTH-HB composite showed better dispersion property and improvedfluorescence performance under the same experimental conditions. UsingSiO2@COFBMTH-HB as a fluorescence probe, the fluorescence intensity was gradually decreased with the addition of Cu2+, while it was restored by introducing Cys or Hcy, realizing "ON-OFF-ON" fluorescence sensing detection. Other amino acids with fivetimes the concentration of Cys showed little effect on the determination of Cys or Hcy. The SiO2@COFBMTH-HB-Cu2+ probe exhibited ultrahigh sensitivity and good selectivity for the detection of Cys and Hcy, with a detection range of 0.23 to 250.0µM for Cys and 0.31 to 170.0µM for Hcy. The detection limits (LOD = 3 σ/s) were 75 and 104nM for Cys and Hcy, respectively. The system also showed a good recovery and low relative standard deviations in actual sample tests for Cys or Hcy, demonstrating its potential for practical applications.

Monolayer and bilayer BP as efficient optoelectronic materials in visible and ultraviolet regions

Hexagonal boron phosphide (BP) shows significant promise for optoelectronic applications due to its high carrier mobility and moderate band gap. Strain inevitably occurs during the synthesis of two-dimensional (2D) nanomaterials. In this work, a detailed study on the strain-dependent phonon dispersion and optical properties of monolayer and bilayer BP was performed. The calculated phonon dispersion curves demonstrate that both monolayer and bilayer BP systems remain dynamically stable under tensile strain. By increasing tensile strain, the LO and TO modes soften and the phonon band gap between optical and acoustic modes becomes narrower. The LO and TO modes display expanded phonon spectra under large tensile strains in contrast to the ZA mode. The absorption edge of bilayer BP is located around 0.6 eV, lower in energy with respect to the monolayer BP at ∼ 0.8 eV. The results indicate that the optical absorption may be enhanced by applying the compressive strain. With their broad absorption range and strain-tunable absorption strength and phononic properties, monolayer and bilayer BP are highly promising for next-generation nanodevices.

New Advances on the Dispersive and Polar Surface Properties of Poly(styrene-co-butadiene) Using Inverse Gas Chromatography.

The IGC surface technique led to the dispersive and polar properties of poly(styrene-co-butadiene) rubber (SBR) by adsorption of organic solvents at various temperatures. Our new methodology, based on the thermal Hamieh model and the London dispersion interaction energy, was used to determine the London dispersion surface energy, the polar acid-base surface energy, and the Lewis acid-base properties of the copolymer. The different surface energy parameters of the SBR were obtained as a function of temperature from the chromatographic measurements. The dispersive and polar free energies of adsorption of the various n-alkanes and polar molecules on poly(styrene-co-butadiene) were determined at different temperatures. A decrease in the London dispersive surface energy and the polar Lewis acid-base surface energies of SBR was highlighted when the temperature increased. It showed a Lewis amphoteric character of poly(styrene-co-butadiene) with a highest basic constant 10 times larger than its acidic constant. This new and original method can better characterize the surface thermodynamic properties of poly(styrene-co-butadiene).

Impact of longitudinal magnetic fields on EIT linewidth and dispersive properties in 87Rb vapor

By employing the density matrix approach, this study systematically examines the impact of a longitudinal magnetic field on electromagnetically induced transparency (EIT) within the context of the effective three-level Zeeman sublevels associated with the D 2 -line of 87Rb atomic vapor. Our investigation reveals that a sufficient enhancement in the longitudinal magnetic field induces a discernible narrowing of the EIT linewidth, accompanied by an enhancement in the peak transmission through a Rubidium (Rb) vapor cell. Related to these, we analyse the effect of magnetic field on the dispersive properties of the system, including group delay and group velocity and observed a slight decrement in the group delay and increment in the group velocity, which specifies the transition from slow to fast light under the application of the magnetic field.