Relative Particle Number Research Articles

Magnetic Effects in Textile Fibers Filled with Nanoconstituents Based on Iron Oxides

ABSTRACT The paper proves the possibility of providing magnetic properties in the process of saturation of textile fibers with a nanomixture of divalent and trivalent iron oxides. The mechanisms of interaction of nanostructures with natural and synthetic fibers are analyzed. The peculiarities of the introduction of magnetic components into flax, cotton, polyamide, and polyester fibers are determined. The relative number of particles with nanoscale in the total was statistically proved. To evaluate the macro effects of saturation, the relative amount of the accumulated mixture of divalent and trivalent iron oxides was determined, taking into account the previous fiber weight. Two basic constants characterizing the properties of textile fibers to magnetic interaction are proposed. It is proved that flax fibers exhibit the highest magnetic efficiency. The average size of iron oxide nanoparticles is 80–90 nanometers, which is confirmed by studies using electron microscopy. The final magnetization of the obtained textile materials provides an attractive magnetization of 20–30 mPascal. The magnetic field of magnetic textile fibers acts at a height of up to 6–7 mm. The directions of the use of fibers with magnetic properties are shown as a prospect for the development of textile smart products.

Environmental DNA Particle Size Distribution and Quantity Differ Across Taxa and Organelles

ABSTRACTThe use of environmental DNA to detect species is now widespread in freshwater ecology. However, the detectability of species depends on many factors, such as the quantity of eDNA particles available in the environment and their state (e.g., free DNA fragments, organellar, or aggregated DNA particles). To date, the most advanced knowledge of the production and state of DNA particles concerns teleosts. Most often, these studies target mitochondrial genes, since they are present in multiple copies in a cell. However, it is likely that the characteristics of eDNA molecules vary greatly among taxa and genetic compartments, with direct consequences for species detection. Using an indoor mesocosm experiment, we compared the rate of mitochondrial and nuclear eDNA production and particle size distribution (PSD) of four distinct and common aquatic taxa (zebrafish, tadpole, isopod and mollusk). The tank water was filtered through a series of filters with decreasing porosity and mitochondrial and nuclear eDNA at each size fraction were quantified by qPCR. We found that the production and the size of eDNA particles varied greatly among taxa and genetic compartments. For most taxa, the number of nuclear eDNA particles released in water was higher than that of mitochondrial origin. The PSD of mt‐eDNA showed a pattern common to all taxa: the relative number of particles increased from the smallest size fractions (0.2 μm and less) to the largest (over 1.2 μm), while the distribution of nu‐eDNA was very different from one taxon to another. We also observed a high temporal variability in the quantity of eDNA particles and in PSD, although the latter was more complex to model. These results call for caution in how to sample and analyze eDNA in aquatic environments, particularly for organisms that emit small particles in small quantities such as isopods.

The effects of monomer type, filler size, and filler content of three resin cements on the color stability of laminate veneers exposed to accelerated aging

Statement of problemCommercially available resin cements consist of various filler sizes, filler content and monomers, and it is unclear which of these factors have the greatest effect on the color stability of laminate veneers. ObjectivesTo evaluate the color stability of lithium disilicate-reinforced laminate veneers inserted with three commercial resin cements with various filler sizes/contents and monomers upon accelerated aging. MethodsVeneers were fabricated and cemented on resin abutments using three commercially available resin cements comprised of two different monomers and varying filler sizes/contents: 1) triethylene glycol dimethacrylate, TEGDMA (RelyX™ Veneer = 0.6 µm/66 %, Calibra® Esthetic Light Cure =1.2 µm/65 %); and 2) urethane dimethacrylate, UDMA (Variolink Esthetic LC = 0.1 µm/38 %). A total of 60 specimens were fabricated (n = 20 for each cement). The relative number of particles (N) and relative surface area (A) were calculated for each filler size/content. Color coordinates (L*, a*, b*) were measured, and color change (ΔE00) was calculated after cementation and following aging at 150, 300, 450, and 600 h using xenon light. Differences in color coordinates and color change were determined using repeated measures ANOVA followed by Tukey's post hoc test (α = .05). A post-hoc power analysis was performed to confirm reliability of the results. ResultsBased on a post-hoc power analysis of a repeated measures ANOVA with two between-factors and 1 within-factor, we had 89 % power to detect a difference of effect by cement type, 10 % power to detect a difference by shade, and 100 % power to detect a difference of effect by aging. The UDMA-based cement (0.1 µm/38 %) was least affected by aging, despite having the largest number of particles (N = 1010) and largest particle surface area (A = 7.02). The TEGDMA-based cements exhibited a significant color change, with 0.6 µm/66 % (A = 2.03, N = 8.12) producing a larger ΔE00 than 1.2 µm/65 % (A = 1.00, N = 1.00). ConclusionsAmong the commercial cements tested, UDMA-based resin (0.1 µm/38 %) provided better color stability than TEGDMA-based resin cements. The color change after aging was affected by the relative surface area and relative number of particles for the TEGDMA-based resin cement (0.6 µm/66 % and 1.2 µm/65 %), with a larger surface area and a higher relative number of particles, accelerated color change with aging. The present study demonstrates a novel approach to determine color stability for any resin cement with particulate filler. Clinical implicationsThe dental practitioner should be selective in choosing a commercial light cure cementation product for laminate veneers, as UDMA containing resin cement is more resistant to color changes over time than TEGDMA, regardless of the filler size/content.

Phage-host co-evolution has led to distinct generalized transduction strategies.

Generalized transduction is pivotal in bacterial evolution but lacks comprehensive understanding regarding the facilitating features and variations among phages. We addressed this gap by sequencing and comparing the transducing particle content of three different Salmonella Typhimurium phages (i.e. Det7, ES18 and P22) that share a headful packaging mechanism that is typically initiated from a cognate pac site within the phage chromosome. This revealed substantial disparities in both the extent and content of transducing particles among these phages. While Det7 outperformed ES18 in terms of relative number of transducing particles, both phages contrasted with P22 in terms of content. In fact, we found evidence for the presence of conserved P22 pac-like sequences in the host chromosome that direct tremendously increased packaging and transduction frequencies of downstream regions by P22. More specifically, a ca. 561 kb host region between oppositely oriented pac-like sequences in the purF and minE loci was identified as highly packaged and transduced during both P22 prophage induction and lytic infection. Our findings underscore the evolution of phage transducing capacity towards attenuation, promiscuityor directionality, and suggest that pac-like sequences in the host chromosome could become selected as sites directing high frequency of transduction.

Properties of ground state and quench dynamics of one-dimensional contact repulsive single-spin flipped Fermi gases

Based on the exact solution method, the ground state and quench dynamics properties of one-dimensional single-spin flipped Fermi gas with repulsion interaction are studied. With the Bethe wave function, the single-body correlation function and two-body correlation function of the ground state and those between different eigen-states can be reduced into a summation of simple functions, thereby greatly reducing the computational difficulty. For the system in the ground state, the single-body correlation functions and two-body correlation functions as well as momentum distributions for spin-up particles are investigated in real space with different interaction strengths. As the interaction strength increases, the number of nodes in the single-body correlation function remains unchanged, while the amplitude of oscillation decreases. Meanwhile, the number of peaks in the two-body correlation function increases by one due to interaction, indicating that the spin-down particle behaves as a spin-up particle. The momentum distribution becomes more smooth around Fermi surface with the interaction strength increasing. The interaction quench dynamics is investigated. The system is prepared in the ground state of ideal Fermi gas, and then the interaction strength is quenched to a finite positive value. The system evolves under time-dependent Schrödinger equation. The overlap between the initial state and eigen-state of post-quench interaction strength is expressed in the form of continued multiplication. The square of the modulus of this overlap, which represents the occupation probability, is calculated. We find that the occupation probabilities of the ground state and doubly degenerated excited state always have the first and the second largest value for an arbitrary interaction strength, respectively, which means that the difference in eigenenergy between these two states gives the primary period of oscillation. For relatively large particle number (<inline-formula><tex-math id="M2">\begin{document}$ N\geqslant10$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="2-20231425_M2.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="2-20231425_M2.png"/></alternatives></inline-formula>), the primary period always does not change under different interaction strengths.It is found that in the case of interaction quenching, the momentum distribution and the correlation function show periodic oscillations. When the interaction strength is adjusted to a relatively small value, the oscillation periodicity is well-defined and the oscillation amplitude is small. The system can be approximated by a two-level model. When the interaction strength increases to a very large value, the oscillation periodicity worsens and the amplitude increases, but a primary period remains unchanged. Although the overall deviation is far from the initial state, it is very close to the initial state at time <inline-formula><tex-math id="M3">\begin{document}$ t=mL^2/(2\pi\hbar)$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="2-20231425_M3.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="2-20231425_M3.png"/></alternatives></inline-formula>. This is because the difference between most energy eigenvalues is almost an integral multiple of energy unit <inline-formula><tex-math id="M4">\begin{document}$ 2\times\left(2\pi/L\right)^{2}$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="2-20231425_M4.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="2-20231425_M4.png"/></alternatives></inline-formula>.

Concentrations of tire wear microplastics and other traffic-derived non-exhaust particles in the road environment

Tire wear particles (TWP) are assumed to be one of the major sources of microplastic pollution to the environment. However, many of the previously published studies are based on theoretical estimations rather than field measurements. To increase the knowledge regarding actual environmental concentrations, samples were collected and analyzed from different matrices in a rural highway environment to characterize and quantify TWP and other traffic-derived non-exhaust particles. The sampled matrices included road dust (from kerb and in-between wheeltracks), runoff (water and sediment), and air. In addition, airborne deposition was determined in a transect with increasing distance from the road. Two sieved size fractions (2–20 µm and 20–125 µm) were analyzed by automated Scanning Electron Microscopy/Energy Dispersive X-ray spectroscopy (SEM/EDX) single particle analysis and classified with a machine learning algorithm into the following subclasses: TWP, bitumen wear particles (BiWP), road markings, reflecting glass beads, metals, minerals, and biogenic/organic particles. The relative particle number concentrations (%) showed that the runoff contained the highest proportion of TWP (up to 38 %). The share of TWP in kerb samples tended to be higher than BiWP. However, a seasonal increase of BiWP was observed in coarse (20–125 µm) kerb samples during winter, most likely reflecting studded tire use. The concentration of the particle subclasses within airborne PM80-1 decreases with increasing distance from the road, evidencing road traffic as the main emission source. The results confirm that road dust and the surrounding environment contain traffic-derived microplastics in both size fractions. The finer fraction (2–20 µm) dominated (by mass, volume, and number) in all sample matrices. These particles have a high potential to be transported in water and air far away from the source and can contribute to the inhalable particle fraction (PM10) in air. This highlights the importance of including also finer particle fractions in future investigations.

Size Distribution and Source Appointment of Road Particles During Winter in Tianjin

The significant role of traffic emissions mixed from various sources in urban air pollution has been widely recognized. However, the corresponding contributions to the roadside particle distribution are poorly understood due to the mixed impacts of various sources. Particle number concentrations of different sizes at the roadside in Nankai District of Tianjin were continuously monitored using a portable aerosol particle spectrometer during the morning rush hour (07:30-09:20) from Nov. 9, 2018 to Jan. 6, 2019. Characteristic and influencing factors of particle size distributions were discussed combined with temperature and relative humidity data, while potential sources of particles at the roadside were identified based on size distribution analysis. The results showed that the average total particle number concentrations were 502 cm-3, and the concentrations of the accumulation mode and coarse mode were 500 cm-3 and 2 cm-3, respectively. The distribution of number concentrations at the roadside was unimodal and primarily concentrated at 0.25-0.50 μm, with peak sizes at 0.28-0.30 μm. The same distribution trend of particle number concentration and difference in the concentration in the same segment size were observed at different periods. Vehicle activity level was the main influencing factor of road particulate matter concentration on different weekdays; the probability of the high value of road particulate matter concentration was reduced by a reasonable combination of the vehicle tail numbers. Temperature and relative humidity were both found to be positively correlated with the number concentration of particles. With the increase in temperature and relative humidity, the total and peak particle number concentration showed an overall upward trend. In addition, the peak particle size increased from 0.28-0.30 μm to 0.35-0.40 μm when relative humidity was higher than 80%. Three sources, including road dust, brake and tire wear, and the aging particles from vehicle exhaust, were identified using positive matrix factorization in this study. Road dust contributed 8.6% of the total number concentration, which mainly consisted of particles with sizes above 5.00 μm. Brake and tire wear contributed 2.8% of the total number concentration of particles with a size range of 0.80-4.00 μm. The aging particles from vehicle exhaust contributed the most (88.5%), with a peak at 0.25-0.65 μm. The sources of roadside particles were mainly related to vehicle activity, whereas temperature and relative humidity also affected the particle number size distribution.

Early osseointegration of strontium-doped coatings on titanium implants in an osteoporotic rat model

Osteoporosis is a skeletal disorder characterized by a decrease in bone strength leading to a higher risk of fracture. In this scenario, many osteoporotic patients require permanent prosthesis. Surface modification is a strategy to improve the osseointegration for cementless implants. This work assesses the in vivo performance of a surface modification consisting in a bioactive silica-based layer with strontium-doped bioactive glass particles. The layer was made by sol-gel and applied onto titanium nail-shaped implants. Osseointegration tests were performed on an osteoporotic rat model generated by ovariectomization. The effectiveness of the osteoporotic rat model was systematically analyzed for structure and bone quality using classic and novel techniques: nanoindentation, micro-Raman spectroscopy and digital image processing. It was found that Sr- glass coatings applied on nail-shaped implants result with lower numbers of particles than for plane samples. The positive effect of bioactive Sr-glass coatings on the new bone tissue formation was evident from the results of the Raman tests. Besides, histomorphometric results showed that the newly formed bone thicknesses around coated Sr-bioactive implants are 15% larger than those formed around titanium materials 15 and 30 days after implantation. These results indicated that even when the nail-shaped implants have a relative low number of bioactive Sr-glass particles, they have a positive effect to induce the formation of new bone. Further research is needed to find the means to increase the number of particles in the coating, while tests at longer times are necessary to investigate the period of effectiveness.

Information constraint in open quantum systems

We propose an effect called information constraint which is characterized by the existence of different decay rates of signal strengths propagating along opposite directions. It is an intrinsic property of a type of open quantum systems, which does not rely on boundary conditions. We define the value of information constraint $({I}_{C})$ as the ratio of different decay rates and derive the analytical representation of ${I}_{C}$ for general quadratic Lindbladian systems. Based on information constraint, we can provide a simple and elegant explanation of chiral and helical damping, and get the local maximum points of relative particle number for the periodical boundary system, consistent with numerical calculations. Inspired by information constraint, we propose and prove the correspondence between edge modes and damping modes. A new damping mode called Dirac damping is constructed, and chiral/helical damping can be regarded as a special case of Dirac damping.

Air particulate concentration during orthodontic procedures: a pilot study

BackgroundThis study evaluates the particle dispersion involved in dental procedures carried out during orthodontic treatments. Variants such as temperature and relative humidity in the dental cabinet were considered.MethodsUsing a particle counter, a pilot study was conducted, in which 98 consecutive recordings were made during appointments of patients undergoing orthodontic treatments. Temperature, relative humidity and particles present at the beginning (AR) and during the appointment (BR) were recorded. A control record (CR) of temperature, relative humidity and particles present was made before the start of the clinical activity. In addition to conventional statistics, differential descriptive procedures were used to analyse results, and the influence of relative humidity on particle concentration was analysed by statistical modelling with regression equations.ResultsThe number of particles present, regardless of their size, was much higher in AR than in CR (p < .001). The same was true for relative humidity and ambient temperature. The relationship between relative humidity and particle number was determined to be exponential.Limitations of the studyThe limitations are associated with sample size, environmental conditions of the room and lack of discrimination among the procedures performed.ConclusionsThis pilot study shows that from the moment a patient enters a dental office, a large number of additional particles are generated. During treatment, the number of particles of 0.3 microns—which have a high capacity to penetrate the respiratory tract-increases. Moreover, a relationship between relative humidity and particle formation is observed. Further studies are needed.

Emissions of ultrafine particles from five types of candles during steady burn conditions.

Emissions from candles are of concern for indoor air quality. In this work, five different types of pillar candles were burned under steady burn conditions in a new laboratory scale system for repeatable and controlled comparison of candle emissions (temperature ~25°C, relative humidity ~13%, O2 >18%, air exchange rate 1.9h-1 ). Burn rate, particle number concentrations, mass concentrations, and mode diameters varied between candle types. Based on the results, the burning period was divided in two phases: initial (0-1h) and stable (1-6h). Burn rates were in the range 4.4-7.3 and 4.7-7.1g/h during initial and stable phase, respectively. Relative particle number emissions, mode diameters, and mass concentrations were higher during the initial phase compared to the stable phase for a majority of the candles. We hypothesize that this is due to elevated emissions of wick additives upon ignition of the candle together with a slightly higher burn rate in the initial phase. Experiments at higher relative humidity (~40%) gave similar results with a tendency toward larger particle sizes at the higher relative humidity. Chemical composition with respect to inorganic salts was similar in the emitted particles (dry conditions) compared to the candlewicks, but with variations between different candles.

Flocculation of PVC Microplastic and Fine-Grained Cohesive Sediment at Environmentally Realistic Concentrations.

AbstractMicroplastic particles have become ubiquitous in aquatic environments and can be found in large numbers in riverine, estuarine, and marine settings at the surface of water, in suspension, and as particles deposited at the bed. The transport and settling behavior of small microplastic particles is likely very dependent on interactions with other suspended particles. Here we show from settling tube experiments conducted in the laboratory that fragments and threads of polyvinylchloride microplastic in the size range of 63-125 µm readily flocculated with fine-grained natural sediment under relative particle number concentrations that can be observed in nature in high-turbidity estuarine and coastal environments. The implication of this flocculation is that the microplastic particles are suspended and transported incorporated in aggregates that settle faster than the individual microplastic particles. This is causing a continuous sedimentation of microplastic particles in estuarine and marine settings, resulting in increased microplastic loading for benthic life in these environments.

Small-Ncollisional dynamics – V. FromN≲ 10 toN≳ 103

ABSTRACTDirect collisions between finite-sized particles occur commonly in many areas of astrophysics. Such collisions are typically mediated by chaotic, bound gravitational interactions involving small numbers of particles. An important application is stellar collisions, which occur commonly in dense star clusters, and their relevance for the formation of various types of stellar exotica. In this paper, we return to our study of the collision rates and probabilities during small-number chaotic gravitational interactions ($N\, \lesssim$ 10), moving beyond the small-number particle limit and into the realm of larger particle numbers ($N\, \gtrsim$ 103) to test the extent of validity of our analytic model as a function of the particle properties and the number of interacting particles. This is done using direct N-body simulations of stellar collisions in dense star clusters, by varying the relative numbers of particles with different particle masses and radii. We compute the predicted rate of collisions using the mean free path approximation, adopting the point-particle limit and using the sticky-star approximation as our collision criterion. We evaluate its efficacy in the regime where gravitational focusing is important by comparing the theoretical rates to numerical simulations. Using the tools developed in previous papers in this series, in particular Collision Rate Diagrams, we illustrate that our predicted and simulated rates are in excellent agreement, typically consistent with each other to within 1 standard deviation.

Biogenic Aggregation of Small Microplastics Alters Their Ingestion by a Common Freshwater Micro-Invertebrate

In recent years, increasing concerns have been raised about the environmental risk of microplastics in freshwater ecosystems. Small microplastics enter the water either directly or accumulate through disintegration of larger plastic particles. These particles might then be ingested by filter-feeding zooplankton, such as rotifers. Particles released into the water may also interact with the biota through the formation of aggregates, which might alter the uptake by zooplankton. In this study, we tested for size-specific aggregation of polystyrene microspheres and their ingestion by a common freshwater rotifer Brachionus calyciflorus. The ingestion of three sizes of polystyrene microspheres (MS) 1-, 3-, and 6-μm was investigated. Each MS size was tested in combination with three different treatments: MS as the sole food intake, MS in association with food algae and MS aggregated with biogenic matter. After 72 h incubation in pre-filtered natural river water, the majority of the 1-μm spheres occurred as aggregates. The larger the particles, the higher the relative number of single particles and the larger the aggregates. All particles were ingested by the rotifer following a Type-II functional response. The presence of algae did not influence the ingestion of the MS for all three sizes. The biogenic aggregation of microspheres led to a significant size-dependent alteration in their ingestion. Rotifers ingested more microspheres (MS) when exposed to aggregated 1- and 3-μm MS as compared to single spheres, whereas fewer aggregated 6-μm spheres were ingested. This indicates that the small particles when aggregated were in an effective size range for Brachionus, while the aggregated larger spheres became too large to be efficiently ingested. These observations provide the first evidence of a size- and aggregation-dependent feeding interaction between microplastics and rotifers. Microplastics when aggregated with biogenic particles in a natural environment can rapidly change their size-dependent availability. The aggregation properties of microplastics should be taken into account when performing experiments mimicking the natural environment.

Characterization of Gamma Knife Perfexion™ source based on Monte Carlo simulation

This study is aimed at characterizing a single Cobalt-60 source capsule of the Gamma Knife Perfexion™ unit using the BEAMnrc Monte Carlo code. The Gamma Knife Perfexion™ source capsule was modeled using the BEAMnrc user code according to the manufacturer's technical details. The modeled parts include the source, the area around the source, and the capsule. The cylindrical source is 1mm in diameter and 17mm in length, with a physical density (ρ) of 8.9 × 103kg/m3. The simulation parameters were an electron cutoff energy (ECUT) of 0.7meV and photon cutoff energy (PCUT) of 0.01meV. Energy fluence was calculated on a 0.25cm diameter scoring plane located 3.1cm from the source. Simulations were performed with and without the encapsulation of the source to investigate its effect on the spectrum and fluence of emitted gamma rays. The results showed that the influence of source encapsulation on the gamma rays is an increase in the relative number of particles in each energy bin of aggregate gamma rays by 92.36% at 0.23meV energy and 66.12% at 1.10meV energy. The secondary gamma rays were found to increase by 94.17% at 0.23meV energy and 63.74% at 1.10meV energy. The encapsulation of the source attenuated the gamma rays, which altered the spectrum. The mean energy of the beam increased, thereby exhibiting a beam-hardening effect.

A Study on the Analysis of Particle Size Distribution for Bimodal Model Nanoparticles by Electron Microscopy

The present study addresses the capability of measurement of relative particle number concentration by scanning electron microscopy for model bimodal silica and gold samples prepared in the frame of the European research project “nPSize - Improved traceability chain of nanoparticle size measurements” as candidate reference nanoparticles.

Phase separation in trapped dipolar Fermi gases

We study the ground state of a two-component dipolar Fermi gas in a spherically symmetric harmonic trap at zero temperature. We obtain the ground state of the system with equal but opposite values of the magnetic moment on the basis of the Thomas--Fermi--von Weizs\acker approximation. It is found that two types of phase-separated states which break the spherical symmetry emerge across the phase transition between a spin-symmetric phase and a phase-separation phase. One is an axially symmetric phase-separated state and the other is a one-dimensional alternating-spin layered state. We also study a Fermi-Fermi mixture of polarized Dy and Er atoms and show that a structural transition of phase separation can be observed in current experiments by varying the relative number of particles.

Smoluchowski equations for linker-mediated irreversible aggregation.

We developed a generalized Smoluchowski framework to study linker-mediated aggregation, where linkers and particles are explicitly taken into account. We assume that the bonds between linkers and particles are irreversible, and that clustering occurs through limited diffusion aggregation. The kernel is chosen by analogy with single-component diffusive aggregation but the clusters are distinguished by their number of particles and linkers. We found that the dynamics depends on three relevant factors, all tunable experimentally: (i) the ratio of the diffusion coefficients of particles and linkers; (ii) the relative number of particles and linkers; and (iii) the maximum number of linkers that may bond to a single particle. To solve the Smoluchoski equations analytically we employ a scaling hypothesis that renders the fraction of bondable sites of a cluster independent of the size of the cluster, at each instant. We perform numerical simulations of the corresponding lattice model to test this hypothesis. We obtain results for the asymptotic limit, and the time evolution of the bonding probabilities and the size distribution of the clusters. These findings are in agreement with experimental results reported in the literature and shed light on unexplained experimental observations.

Effect of hyperon coupling constants on the properties of the massive neutron star PSR J0348+0432

The relativistic mean field (RMF) theory is used to examine the effect of the meson-[Formula: see text] coupling constants on the properties of the neutron star (NS) PSR J0348+0432 when the hyperon potential of [Formula: see text] is fixed. It is found that the greater the [Formula: see text] and [Formula: see text], the stronger the repulsive interaction. The potential field strengths of mesons [Formula: see text] and [Formula: see text] and the chemical potentials of neutron n and electron e increase, whereas the potential field strengths of mesons [Formula: see text] decrease with the increase of the meson-[Formula: see text] coupling constants. It is also found that the relative particle number density of neutron [Formula: see text] and hyperon [Formula: see text] in the NS PSR J0348+0432 increase, whereas that of hyperon [Formula: see text] decrease as the meson-[Formula: see text] coupling constants increase. In our calculations, hyperon [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] all do not appear. Our results show that the meson-[Formula: see text] coupling constants cannot be uniquely determined as the hyperon-potential of [Formula: see text] is determined. Therefore, the related properties of NS cannot be uniquely determined only by the determined hyperon potential of [Formula: see text].

Effect of the mesons on the baryons distribution in the massive NS PSR J0348+0432

Effect of the mesons $f_{0}(975)$ and $\phi (1020)$ on the baryons distribution in the massive neutron star PSR J0348+0432 is examined in the framework of the relativistic mean field theory. It is found that the value range of the central baryon number density increases compared with that without considering the mesons $f_{0}(975)$ and $\phi (1020)$ under the restriction of the observation mass of the massive neutron star PSR J0348+0432. It is also found that the relative particle number density of neutrons decreases and in the center of the neutron star its value range also decreases as the mesons $f_{0}(975)$ and $\phi (1020)$ being considered. This means that there will be more neutrons changing into other baryons considering the mesons $f_{0}(975)$ and $\phi (1020)$ . But the effect of the mesons $f_{0}(975)$ and $\phi (1020)$ on the relative particle number density of protons is very small. The relative particle number density of hyperon $\varLambda $ and $\varXi ^{-}$ all increase compared with that without considering the mesons $f_{0}(975)$ and $\phi (1020)$ . At the neutron star center, the value range of them all increase compared with that without considering the mesons $f_{0}(975)$ and $\phi (1020)$ by the observation mass of the massive neutron star PSR J0348+0432 $M=1.97\mbox{--}2.05~\mathrm{M}_{\odot }$ . Our calculations also show that the hyperons $\varSigma ^{-}$ , $\varSigma ^{0}$ , $\varSigma ^{+}$ and $\varXi ^{0}$ are not produced.