We extend the quark mean-field (QMF) model for nuclear matter and study the possible presence of quark matter inside the cores of neutron stars. A sharp first-order hadron-quark phase transition is ...implemented combining the QMF for the hadronic phase with "constant-speed-of-sound" parameterization for the high-density quark phase. The interplay of the nuclear symmetry energy slope parameter, L, and the dimensionless phase transition parameters (the transition density ntrans/n0, the transition strength Δ / trans, and the sound speed squared in quark matter ) are then systematically explored for the hybrid star properties, especially the maximum mass Mmax and the radius and the tidal deformability of a typical 1.4 M star. We show the strong correlation between the symmetry energy slope L and the typical stellar radius R1.4, similar to that previously found for neutron stars without a phase transition. With the inclusion of phase transition, we obtain robust limits on the maximum mass (Mmax < 3.6 M ) and the radius of 1.4 M stars (R1.4 9.6 km), and we find that a phase transition that is too weak (Δ / trans 0.2) taking place at low densities 1.3-1.5 n0 is strongly disfavored. We also demonstrate that future measurements of the radius and tidal deformability of ∼1.4 M stars, as well as the mass measurement of very massive pulsars, can help reveal the presence and amount of quark matter in compact objects.
Abstract
Observations of optical and near-infrared counterparts of binary neutron star mergers not only enrich our knowledge about the abundance of heavy elements in the universe and help reveal the ...remnant object just after the merger, which is generally known, but can also effectively constrain the dense properties of the nuclear matter and the equation of state (EOS) in the interior of the merging stars. Following the relativistic mean-field description of nuclear matter, we perform a Bayesian inference of the EOS and the properties of the nuclear matter using the first multi-messenger event GW170817/AT2017gfo, together with the NICER mass–radius measurements of pulsars. The kilonova is described by a radiation-transfer model with the dynamical ejecta, and light curves connect with the EOS through the quasi-universal relations between the properties of the ejecta (the ejected mass, velocity, opacity, or electron fraction) and binary parameters (the mass ratio and reduced tidal deformability). It is found that the posterior distributions of the reduced tidal deformability from the AT2017gfo analysis display a bimodal structure, with the first peak enhanced by the GW170817 data, leading to slightly softened posterior EOSs, while the second peak cannot be achieved by a nuclear EOS with saturation properties in their empirical ranges. The inclusion of NICER data results in a stiffened EOS posterior because of the massive pulsar PSR J0740+6620. We provide the results at nuclear saturation density for the nuclear incompressibility, the symmetry energy, and its slope, as well as the nucleon effective mass, from our analysis of the observational data.
Detection of gravitational waves (GWs) produced by coalescence of compact binaries provides a novel way to measure the luminosity distance of GW events. Combining their redshift, they can act as ...standard sirens to constrain cosmological parameters. For various GW detector networks in second-generation (2G), 2.5G, and 3G, we comprehensively analyze the method to constrain the equation-of-state (EOS) of binary neutron stars (BNSs) and extract their redshifts through the imprints of tidal effects in GW waveforms. We find for these events that the observations of electromagnetic counterparts in the low-redshift range z < 0.1 are important for constraining the tidal effects. Considering 17 different EOSs of NSs or quark stars, we find GW observations have strong capability to determine the EOS. Applying the events as standard sirens, and considering the constraints of NS's EOS derived from low-redshift observations as prior, we can constrain the dark energy EOS parameters w0 and wa. In the 3G era, the potential constraints are Δw0 (0.0006,0.004) and Δwa (0.004,0.02), which are 1-3 orders smaller than those from traditional methods, including Type Ia supernovae (SNe Ia) and baryon acoustic oscillations. The constraints are also made 1 order smaller than the method of GW standard siren by fixing the redshifts through short-hard γ-ray bursts, due to more available GW events in this method. Therefore, GW standard sirens, based on the tidal effect measurement, provide a realizable and much more powerful tool in cosmology.
The evolution of the gravitational-wave phase in the signal produced by inspiralling binaries of compact stars is modified by the nonzero deformability of the two stars. Hence, the measurement of ...these corrections has the potential of providing important information on the equation of state of nuclear matter. Extensive work has been carried out over the last decade to quantify these corrections, but it has so far been restricted to stars with zero intrinsic magnetic fields. While the corrections introduced by the magnetic tension and magnetic pressure are expected to be subdominant, it is nevertheless useful to determine the precise conditions under which these corrections become important. To address this question, we have carried out a second-order perturbative analysis of the tidal deformability of magnetized compact stars under a variety of magnetic-field strengths and equations of state describing either neutron stars or quark stars. Overall, we find that magnetically induced corrections to the tidal deformability will produce changes in the gravitational-wave phase evolution that are unlikely to be detected for a realistic magnetic field i.e., B ∼ 1010 – 1012 G. At the same time, if the magnetic field is unrealistically large, i.e., B ∼ 1016 G, these corrections would produce a sizeable contribution to the phase evolution, especially for quark stars. In the latter case, and if the neglected higher-order terms will remain negligible also for very high magnetic fields, the induced phase differences would represent a unique tool to measure the properties of the magnetic fields, providing information that is otherwise hard to quantify.
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CMK, CTK, FMFMET, IJS, NUK, PNG, UM
Electron-phonon interaction (EPI) has been widely suited in electrical transport properties. Nevertheless, its critical impact on the lattice thermal transport has been revealed in the last few ...years. Recently, people found that EPI can remarkably reduce the lattice thermal conductivity under a high carrier concentration and low temperature such as in silicon and two-dimensional materials; however, the discussions on thermoelectric (TE) materials are few. In this study, we investigate the EPI effect on the lattice thermal conductivities of skutterudites CoSb
3
and p-type filled BaFe
4
Sb
12
. At 300 K with 10
21
cm
−3
carrier concentration, the lattice thermal conductivity of CoSb
3
decreases from 10.7 W m
−1
K
−1
to 7.03 W m
−1
K
−1
(hole doping, reduction 34.3%) and 8.18 W m
−1
K
−1
(electron doping, reduction 23.6%), respectively, while that of BaFe
4
Sb
12
decreases from 3.24 W m
−1
K
−1
to 1.14 W m
−1
K
−1
(5 × 10
21
cm
−3
for hole concentration) with a reduction of 64.8%. The significant EPI effect in BaFe
4
Sb
12
is mainly due to the large density of states (DOS) and strong EPI strength. Our study reveals that EPI plays an important role in the lattice thermal conductivity of filled skutterudites, and it can further optimize their TE performances.
Due to strong electron-phonon interactions, the lattice thermal conductivity in filled skutterudite BaFe
4
Sb
12
has a significant reduction of 64.8% at 300 K.
Based on the Hodgkin-Huxley model, the present study established a fully connected structural neural network to simulate the neural activity and energy consumption of the network by neural energy ...coding theory. The numerical simulation result showed that the periodicity of the network energy distribution was positively correlated to the number of neurons and coupling strength, but negatively correlated to signal transmitting delay. Moreover, a relationship was established between the energy distribution feature and the synchronous oscillation of the neural network, which showed that when the proportion of negative energy in power consumption curve was high, the synchronous oscillation of the neural network was apparent. In addition, comparison with the simulation result of structural neural network based on the Wang-Zhang biophysical model of neurons showed that both models were essentially consistent.
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•The marine anti-fouling coating was modified by the photocatalysts of graphene/TiO2.•The modified coating has excellent antibacterial activity.•Graphene can improve the separation ...efficiency of photo-generated carriers.•The hydrophobicity of original anti-fouling coating was not reduced by graphene/TiO2.
Marine fouling organisms attachment can bring serious damage to ships and marine facilities. Thus, we modified the hydrophobic fluorocarbon resin coating (PEVE) which was widely used in marine hulls. In this study, graphene/TiO2 nanocomposite photocatalysts have been taken as the raw material of the modification to prepare the composite coatings with anti-fouling performance through a sample method. The results of our experiment demonstrate that when the mass ratio of rGO to TiO2 is 1:100, the composite coating exhibits the best antibacterial property. This coating could kill the vast majority of the bacteria which attached to its surface after one hour of exposure to ultraviolet light, and this sterilization performance is much higher than pure PEVE and TiO2/PEVE coatings. In this composite system, graphene plays an important role in enhancing the coatings performance. For one thing, the heterojunction formed by graphene and TiO2 can effectively increase the hydroxyl radical yields of TiO2. For another, the conjugated structure of graphene can effectively reduce the phenomenon of hydrophobicity reduction which is caused by the addition of TiO2 and then decrease the risk of hull corrosion availably.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Hypothyroidism is a chronic condition of endocrine disorder and its precise molecular mechanism remains obscure. In spite of certain efficacy of thyroid hormone replacement therapy in treating ...hypothyroidism, it often results in other side effects because of its over-replacement, so it is still urgent to discover new modes of treatment for hypothyroidism. Sini decoction (SND) is a well-known formula of traditional Chinese medicine (TCM) and is considered as efficient agents against hypothyroidism. However, its holistic effect assessment and mechanistic understanding are still lacking due to its complex components.
A urinary metabonomic method based on ultra performance liquid chromatography coupled to mass spectrometry was employed to explore global metabolic characters of hypothyroidism. Three typical hypothyroidism models (methimazole-, propylthiouracil- and thyroidectomy-induced hypothyroidism) were applied to elucidate the molecular mechanism of hypothyroidism. 17, 21, 19 potential biomarkers were identified with these three hypothyroidism models respectively, primarily involved in energy metabolism, amino acid metabolism, sphingolipid metabolism and purine metabolism. In order to avert the interference of drug interaction between the antithyroid drugs and SND, the thyroidectomy-induced hypothyroidism model was further used to systematically assess the therapeutic efficacy of SND on hypothyroidism. A time-dependent recovery tendency was observed in SND-treated group from the beginning of model to the end of treatment, suggesting that SND exerted a recovery effect on hypothyroidism in a time-dependent manner through partially regulating the perturbed metabolic pathways.
Our results showed that the metabonomic approach is instrumental to understand the pathophysiology of hypothyroidism and offers a valuable tool for systematically studying the therapeutic effects of SND on hypothyroidism.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Intrahepatic cholangiocarcinoma (ICC), a type of bile duct cancer, has a high mortality rate. Gut microbiota, bile acid (BA) metabolism, and cytokines have not been characterized in patients with ...ICC, and better noninvasive diagnostic approaches for ICC are essential to be established. Therefore, in this study we aimed to improve our understanding of changes in gut microbiota, BA metabolism, and cytokines in patients with ICC. We found that the α‐diversities and β‐diversities of ICC were highest and that the abundances of four genera (Lactobacillus, Actinomyces, Peptostreptococcaceae, and Alloscardovia) were increased in patients with ICC compared with those in patients with hepatocellular carcinoma or liver cirrhosis and in healthy individuals. The glycoursodeoxycholic acid and tauroursodeoxycholic acid (TUDCA) plasma‐stool ratios were obviously increased in patients with ICC. Furthermore, the genera Lactobacillus and Alloscardovia that were positively correlated with TUDCA plasma‐stool ratios were combined to discriminate ICC from the other three diseases. Vascular invasion (VI) frequently led to a poor prognosis in patients with ICC. Compared with patients with ICC without VI, patients with VI had a greater abundance of the family Ruminococcaceae, increased levels of plasma interleukin (IL)‐4 and six conjugated BAs, and decreased levels of plasma IL‐6 and chenodeoxycholic acid. A positive correlation between plasma taurocholic acid and IL‐4 was observed in patients with ICC. Plasma TUDCA was negatively correlated with the abundance of the genus Pseudoramibacter and the survival time of patients with ICC, but had no effect on tumor size, as determined in two murine tumor models. Conclusion: In this study, we identified some biomarkers, including gut microbiota, BAs and inflammatory cytokines, for the diagnosis of ICC and prediction of VI in patients with ICC.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The natural gas hydrates detected in Shenhu Area, South China Sea are considered to have great potential for exploitation and to become a research hotspot. However, details of the dynamic ...accumulation and evolution processes of gas hydrate over a long time in this area remain unclear. In this study, we developed a numerical model to predict the accumulation of gas hydrates in the marine sediments by introducing the biogenic methanogenesis module to the framework of the existing simulator TOUGH+HYDRATE. A one-dimensional dynamic model was applied to reproduce the formation of gas hydrate at site SH2 in Shenhu Area. The burial of sediments and associated phenomena (e.g., evolution of temperature, sediment compaction and consequent reduction in sediment porosity and permeability, fluid expulsion) are taken into account. Modeling results indicate that with the conventional conversion coefficient (CC) of organic carbon to methane of 0.15, the amount of in-situ biogenic methane is not sufficient to form the highly saturated hydrate detected at this location and the remaining methane (91.4%) is supplied by the upward flow of fluids. The tectonic movement that took place about 1.5 Ma created pathways for the fluids to migrate vertically. The pore water and methane gas fluxes in the upward fluids were determined as 2 × 10−10 kg/s·m2 and 1 × 10−11 kg/s·m2, respectively, using the proved hydrate saturation profile and measured pore water chlorinity from recovered core samples. The distribution of hydrate in the sediments is significantly influenced by pore water salinity. The inhibitory effect of salt on hydrate formation, which shifts the pressure of three-phase (i.e., solid hydrate, methane gas and pore water) equilibrium to actual pore water pressure, could be the major reason for the appearance of a three-phase co-existence zone in the hydrate concentrated zone. Additionally, the water flux and diffusivity of salt have a profound effect on the formation of gas hydrate by affecting the salinity of pore water in the gas hydrate concentrated zone. The results of this study are of great significance for guiding marine gas hydrate exploration and resource evaluation.
•Biogenic methane generation module was embedded in the TOUGH+Hydrate code.•The fluxes of pore water and methane in the upward fluids flow were determined using the measured data.•The formation mechanism for the three-phase (water, methane gas and hydrate) co-existence zone was ascertained.•The influence of pore water salinity on hydrate formation and distribution was highlighted.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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