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Nucleonic direct Urca processes and cooling of the massive neutron stars are studied by considering antikaon condensations. Calculations are performed in the relativistic mean field and isothermal interior approximations. Neutrino energy losses of the nucleonic direct Urca processes are reduced when the optical potential of antikaons changes from −80 to −130 MeV. If the center density of the massive neutron stars is a constant, the masses taper off with the optical potential of antikaons, and neutrino luminosities of the nucleonic direct Urca processes decrease for ρCN=0.5 fm−3 but first increase and then decrease for larger ρCN. Large optical potential of antikaons results in warming of the nonsuperfluid massive neutron stars. Massive neutron stars turn warmer with the protonic S01 superfluids. However, the decline of the critical temperatures of the protonic S01 superfluids for the large optical potential of antikaons can speed up the cooling of the massive neutron stars.

In this paper, the gauge method for a special spinor field transformation [PSI](x) [right arrow] [PSI] (x) = exp[(e/m)f(x)[[gamma].sup.a][[partial derivative].sub.a]][PSI](x) is studied. We demonstrate that the Dirac equation involving electromagnetic interactions can be defined by the gauge method for the spinor field transformation, within the framework of gauge field theory.Key words: gauge theory, translation group, covariance, Dirac equation, quantum electrodynamics, teleparallel gravity.Nous etudions ici la methode de la jauge pour une transformation speciale du champ de spineur [PSI](x) [right arrow] [PSI] (x) = exp[(e/m)f(x)[[gamma].sup.a][[partial derivative].sub.a]][PSI](x). Nous demontrons que l'equation de Dirac impliquant les interactions electromagnetiques peut etre definie par la methode de la jauge pour la transformation du champ de spineur, dans le cadre de latheorie des champs de jauge. [Traduit par la Redaction]Mots-cles: theorie de jauge, transformation de jauge, electrodynamique quantique, gravite teleparallele., 1. IntroductionA gauge theory is an important type of field theory in modern physics. The first non-Abelian gauge theory was put forward by Yang and Mills in 1954 [1], and [...]

Well-defined polymer brushes attached to nanoparticles offer an elegant opportunity for surface modification because of their excellent mechanical stability, functional versatility, high graft density as well as controllability of surface properties. This study aimed to prepare hybrid materials with good dispersion in different solvents, and to endow this material with certain fluorescence characteristics. Well-defined diblock copolymers poly (styrene)-b-poly (hydroxyethyl methyl acrylate)−co-poly (hydroxyethyl methyl acrylate- rhodamine B) grafted silica nanoparticles (SNPs-g-PS-b-PHEMA-co-PHEMA-RhB) hybrid materials were synthesized via surface-initiated activators regenerated by electron transfer atom transfer radical polymerization (SI-ARGET ATRP). The SNPs surfaces were modified by 3-aminopropyltriethoxysilane (KH-550) firstly, then the initiators 2-Bromoisobutyryl bromide (BIBB) was attached to SNPs surfaces through the esterification of acyl bromide groups and amidogen groups. The synthetic initiators (SNPs-Br) were further used for the SI-ARGET ATRP of styrene (St), hydroxyethyl methyl acrylate (HEMA) and hydroxyethyl methyl acrylate-rhodamine B (HEMA-RhB). The results indicated that the SI-ARGET ATRP initiator had been immobilized onto SNPs surfaces, the Br atom have located at the end of the main polymer chains, and the polymerization process possessed the characteristic of controlled/“living” polymerization. The SNPs-g-PS-b-PHEMA-co-PHEMA-RhB hybrid materials show good fluorescence performance and good dispersion in water and EtOH but aggregated in THF. This study demonstrates that the SI-ARGET ATRP provided a unique way to tune the polymer brushes structure on silica nanoparticles surface and further broaden the application of SI-ARGET ATRP.

Asteroid families are the remnants of catastrophic collisions, and their fundamental physical properties provide us the information of their parent bodies and thereafter dynamical evolutions. Especially, the orbit and spin characteristics can reveal the influences of the Yarkovsky effect and the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect on the evolution of the asteroid family, respectively. Based on the Asteroid Lightcurve Database (LCDB), the spin rate distribution of the Flora asteroid family is studied, and a tendency that the spin rates of the small Flora family members concentrate primarily in the range of 3–5 d−1 is found. The analysis on the spin states of the Flora family asteroids tells that most of these asteroid family members are in the prograde spinning state. However, for the Flora family members with an orbital semi-major axis smaller than 2.2 au, the ratio between the number of prograde spinning members and that of retrograde ones is close to that of the near-Earth asteroids, namely 1 : 3. Furthermore, for those prograde spinning Flora family asteroids with an orbital semi-major axis larger than 2.2 au, a portion of them exhibit the aggregation in the distribution of orbital semi-major axis against the absolute magnitude, and in which nine members show the features similar to the Slivan state. [ABSTRACT FROM AUTHOR]

The properties of neutron and proton 1S0 superfluidity are studied within the relativistic mean field and the Bardeen-Cooper-Schrieffer theories by taking the effects of K- and K0 condensations into account in neutron star matter without the hyperon degrees of freedom. It is found that antikaon condensations change the Fermi momenta, the effective masses and the single particle energies of nucleons in neutron star matter. These changes lead to a strong suppression of the neutron 1S0 superfluidity and an obvious enhancement of the proton 1S0 superfluidity in neutron star matter, respectively. In particular, the neutron and proton 1S0 pairing gaps are gradually shrinking with the optical potential of antikaons from -80 to -130 MeV. And antikaon condensations have little influence on the neutron 1S0 superfluid range, however, they have been markedly downsized the proton 1S0 superfluid range as the deepening of the optical potential of antikaons in neutron star matter. We also found that the nucleon 1S0 superfluidity and K- condensations within the scope of above optical potential of antikaons can occur in the core of PSR J1614-2230 and PSR J0348+0432 at the same time. Whereas K0 condensations only occur in the two pulsars when the range of optical potential of antikaons is from -100 to -130 MeV. [ABSTRACT FROM AUTHOR]

In the relativistic mean field approximation, the relativistic energy losses of the nucleon direct Urca processes are studied in the degenerate baryon matter of neutron stars. We investigate the effects of hyperon degrees of freedom and the isovector scalar interaction which is considered by exchanging δ meson on the nucleon direct Urca processes in neutron star matter. The results indicate that the existence of hyperons decreases the abundance of protons and leptons and can sharply suppress the neutrino emissivity of the nucleon direct Urca processes, while it has only a little influence on the neutrino luminosity for a fixed neutron star whether δ mesons appear in a neutron star or not. However, the presence of δ mesons can result in obvious growth in the neutrino emissivity and luminosity which will speed up the cooling rate for the nonsuperfluid neutron star. [ABSTRACT FROM AUTHOR]

Abstract: It is difficult to use the single-station satellite laser ranging (SLR) data for orbit determination, due to the singular geometrical distribution of the observations. The single-station data produced by performing the diffuse- reflection SLR on the earth-orbiting space debris are therefore ineffective for orbit improvement. To solve this problem, we propose an orbit determination method by using single-station SLR data in aid of the two-line element set (TLE). For verifying its feasibility, this method is implemented and applied to the orbit determination of the satellite Ajisai, using the single-station SLR data of five passes in one day and the corresponding TLE. And on this basis, the five-day orbit prediction is generated, the result indicates that the errors of predicted positions are less than 40 m. In addition, the potential application of this method in the orbit improvement of space debris is discussed. [Copyright &y& Elsevier]

The nucleonic 1 S 0 superfluidity is investigated by solving the gap equation for the Reid soft-core potential as the nucleon–nucleon interaction in neutron star (NS) matter which is considered to be made up of n, p, e, μ and condensed antikaon matter. We mainly study the influence of the soft pion-induced potential on the nucleonic 1 S 0 pairing gaps in the above NS matter. It is found that the intensities of the nucleonic 1 S 0 pairing gaps including the soft pion-induced potential are smaller than those calculated in the case of not including the soft pion-induced potential. Furthermore, the nucleonic 1 S 0 pairing gaps with the soft pion-induced potential fall into decline with the deepening of the optical potential of antikaons in the above NS matter, whereas they increase with the parameter η for the fixed optical potential of antikaons. Due to the appearance of the soft pion-induced potential, the maximum values of nucleonic 1 S 0 pairing gaps at parameter η = 0.20, 0.55 are suppressed by 1.7%–6.8% with respect to the case without soft pion-induced potential in the above NS matter. [ABSTRACT FROM AUTHOR]

The relativistic neutrino emissivity of the nucleonic direct URCA processes in neutron star matter is investigated within the relativistic Hartree—Fock approximation. We particularly study the influences of the tensor couplings of vector mesons ω and ρ on the nucleonic direct URCA processes. It is found that the inclusion of the tensor couplings of vector mesons ω and ρ can slightly increase the maximum mass of neutron stars. In addition, the results indicate that the tensor couplings of vector mesons ω and ρ lead to obvious enhancement of the total neutrino emissivity for the nucleonic direct URCA processes, which must accelerate the cooling rate of the non-superfluid neutron star matter. However, when considering only the tensor coupling of vector meson ρ, the neutrino emissivity for the nucleonic direct URCA processes slightly declines at low densities and significantly increases at high densities. That is, the tensor coupling of vector meson ρ leads to the slow cooling rate of a low-mass neutron star and rapid cooling rate of a massive neutron star. [ABSTRACT FROM AUTHOR]