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V375 Cassiopeia (V375 Cas) is an early B-type close binary with an orbital period of 1.4734273 d. Based on high-quality and continuous light curves from the Transiting Exoplanet Survey Satellite (TESS) and new low-resolution spectra, we have determined photometric solutions of the eclipsing binary using the Wilson–Devinney method. We have found that V375 Cas is a semidetached binary where the secondary component fills the critical Roche lobe. Meanwhile, its O − C diagram was constructed with the data spanning 122 yr. An upward parabolic variation is discovered to be superimposed on a cyclic modulation with a semi-amplitude of 0.0938 (±0.0143) d and a period of 118.74 (±12.87) yr. The parabolic change reveals a period increase at a rate of |${\rm d}p/{\rm d}t = +5.42 \times {10^{-7}}\, {\rm d} \,\mathrm{yr}^{-1}$|⁠. Both the semidetached configuration and the period increase suggest that V375 Cas is undergoing a late case A mass transfer from the less-massive component to the more-massive component. The cyclic change is attributed to be the effect of the light travel time via the presence of a third body. The minimum mass of the tertiary companion is estimated as M 3 = 4.24 (±0.87) M⊙, which orbits around the central eclipsing binary with a nearly circular orbit (e  = 0.184). It is detected that the light contribution of the third body is about 8.0 per cent, indicating that it is a massive main-sequence star. All the results reveal that V375 Cas is a hierarchical triple system where a massive main-sequence star accompanies a massive semidetached mass-transfer binary at an orbital separation of 60.3 au. [ABSTRACT FROM AUTHOR]

Algol-type binaries (Algols) have aroused extensive interests due to the idiosyncratic evolutionary stages of both components. To better understand the evolutionary properties of such characteristic population, we collected mostly double-lined samples and performed systematic work concentrated on their physical constraints. It is found that orbital period cut-off for the OB and AF type Algols are P (OB) > 0.482 d, P (AF) >0.358 d; constraints on mean density and surface gravity of the secondary components are |$\overline{\rho }_2$| (OB) < 0.144 ρ ⊙, |$\overline{\rho }_2$| (AF) < 0.26  ρ ⊙, log g 2(OB) < 4.719 cgs, and log g 2(AF) < 4.517 cgs. Limitations of a (OB) |$\gt 3.48\, {\rm R}_{\odot }$| and a (AF) |$\gt 2.29\, {\rm R}_{\odot }$| have been deduced from the a – P relation. Moreover, statistical analysis of secular period changes reveal that Algols with higher f 1 and relevant shorter period generally show weak period change. It hints that there is some connections between f 1 and orbital evolution. Systems with lower f 1 have the chance to evolve from classic Algols to SD2-type near contact binaries (NCBs); systems with higher f 1 obey the evolutionary channel from SD2-type NCBs to CBs. However, it seems that SD2-type NCBs could not evolve towards classic Algols. As a natural lab, Algols are producing peculiar stellar experimental samples via complicated astrophysical processes, which will enhance our understanding on the physical properties and evolution of such binary populations. [ABSTRACT FROM AUTHOR]

We reanalysed the c-type RR Lyrae star BE Dor (MACHO 5.4644.8, OGLE-LMC-RRLYR-06002) that had been discovered to show cyclic period changes. The photometric data of several sky surveys (DASCH, MACHO, OGLE, ASAS-SN, and TESS) were used for analyses. The O − C diagram and pulsation period obtained from Fourier analysis show significant period modulations in BE Dor. However, different from the previous viewpoint, the changes are quasi-periodic and abrupt. Therefore, the light-traveltime effect caused by the companion motion cannot explain the changes. Noting a same subtype star KIC 9453114 with similar phenomena has a high macroturbulent velocity, and the degree of O − C changes seem to be positively correlated with these velocities, we consider that the mechanism leading to period modulation should be caused by the interaction between turbulent convection and magnetic field activity in the ionization zone, i.e. the viewpoint of Stothers. It may not explain the general Blazhko effect but should explain such period modulations in BE Dor and those other c-type RR Lyrae stars. We hope our discoveries and viewpoints can provide some information and inspiration for relevant research. [ABSTRACT FROM AUTHOR]

We explore the intrinsic feature of electrocaloric effect (ECE) accompanied by ferroelectric (FE)-paraelectric (PE) transition for displacive-type organic ferroelectrics using Green's function theory. It is demonstrated that decreasing elastic constant K or increasing spin-lattice coupling λ can enhance the ECE, as well as polarization P and transition temperature TC. Indeed, one expects that the optimal operating temperature for solid-state refrigeration is around room temperature, at which the ECE achieves its maximum. As TC is tuned to ~310 K, it presents larger ECE response and remanent polarization with lower coercive field for smaller K value, suggesting that well flexible displacive-type organic ferroelectrics are excellent candidates both for electric cooling and data storage in the design of nonvolatile FE random-access memories. Furthermore, in an electric field, it provides a bridge between a Widom line that denotes FE-PE crossover above TC and a metaelectric transition line below TC that demonstrates an FE switching behavior with an antiparallel field. [ABSTRACT FROM AUTHOR]

GK Cep is an eclipsing binary that contains two A-type components with an orbital period of 0.936 d. The high mass ratio and the contact or near-contact configuration make it a key target to understand binary evolution. However, the physical properties and evolutionary state are still unknown. Here we present the UV light curve obtained by using the lunar-based ultraviolet telescope (LUT) and several eclipse times obtained with the Sino-Thai 70-cm telescope and the 1.0-m telescope at Yunnan Observatories. Analysis of the LUT light curve suggests that GK Cep is a near-contact semidetached system where the slightly less massive component is the hotter one that is filling the critical Roche lobe. Meanwhile, a hotspot is found on the neck of the more massive but cooler component. By using all available times for the light minimum, it is detected that the O–C curve shows a cyclic oscillation while it undergoes an upward parabolic change. The increase of the orbital period, the high mass ratio, the semidetached configuration with a lobe-filling less massive component, and the presence of a hotspot on the more massive component all suggest that GK Cep is in a key evolutionary state just after the shortest-period evolutionary stage during the rapid mass transfer. The cyclic change in the O–C curve reveals that GK Cep contains a solar-type stellar companion in a triply hierarchical system that is in agreement with the spectroscopic result. The third body contributes about 2.6 per cent to the total light of the triple system. [ABSTRACT FROM AUTHOR]

The magnetic vortex, as one of the most interesting magnetic solitons, has attracted great interest over the past two decades. A fast and reliable method to switch vortex polarity and chirality is one of the key issues for various applications. Based on micromagnetic simulation, here we report a fast, low energy cost and deterministic switching of a vortex core, by the designing of a notch structure in disks and the use of out-of-plane current geometry. We demonstrate that with such a design, the multiple switching problems found in notch disk systems can be avoided. Furthermore, the switching time can be reduced by more than 50% compared with disks without notches. [ABSTRACT FROM AUTHOR]

Four sets of complete multicolour light curves of the short-period solar-type eclipsing binary V1005 Her are presented. It is found that the depth of the primary minima in the light curves went deeper from 2013 to 2018, and then became shallower again in 2019, while those of the secondary minima were unchanged. The total-eclipse characteristics in the light curves enable us to determine reliable photometric solutions of this system. Our results from the detailed light-curve analysis show that V1005 Her is a W-type shallow-contact binary with spot activities. We have monitored this system for 7 yr and 22 new times of light minimum have been determined. Together with those collected from the literature, we investigate its Observed-Calculated O – C curve and detect a cyclic variation. Because of the insufficient energy, this cyclic change cannot be explained by magnetic activity cycles of the components even if it has high spots activities. The detected cyclic variation is more plausible as the results of the light-time effect due to the existence of a third body orbiting around the central binary. The minimal mass of the additional stellar companion is determined around 0.45 M⊙ in both circular orbit and eccentric orbit cases when a total mass of 1.2 M⊙ for the binary is adopted. This mass is larger than that of the less massive component of the central binary. It implies that the secondary body was not replaced by the third body during early stellar interactions, suggesting that it is a fossil system and keeps original dynamical information. [ABSTRACT FROM AUTHOR]

The study of applying the C-[Phi] (cohesion and angle of friction) concept to asphalt paving mix design was once an active area of research in the early 1950s. Further research, however, was not pursued subsequently probably due to the complexity and long duration of the laboratory triaxial tests, and the difficulties encountered in relating the test results to field behavior of paving mixtures. Today, with much more advanced test equipment and powerful analytical and computation tools, another look at this theoretically sound approach is justified. By means of a C-[Phi] finite element model, this paper illustrates that a link between Marshall test results and the triaxial test properties of C-[Phi] can be established analytically. This presents a useful tool for analyzing past pavements that were designed on the basis of Marshall criteria. The analytical model is also used to reestablish the C-[Phi] based asphalt paving mix design concept proposed by Smith in 1950, and to show that Smith's analysis model is a poor representation of multilayer asphalt pavement systems. Of special interest is that the proposed analytical C-[Phi] model is able to analyze the behavior of asphalt pavement under load, thereby permitting the incorporation of mechanistic or semimechanistic distress models into asphalt mix design as well as pavement thickness design. It thus offers a potentially useful basis for an integrated procedure for asphalt paving mix design and asphalt pavement design.

About 766 δ Scuti stars were observed by LAMOST by 2017 June 16. Stellar atmospheric parameters of 525 variables were determined, while spectral types were obtained for all samples. In the paper, those spectroscopic data are catalogued. We detect a group of 131 unusual and cool variable stars (UCVs) that are distinguished from the normal δ Scuti stars (NDSTs). On the H-R diagram and the log g-T diagram, the UCVs are far beyond the red edge of pulsational instability trip. Their effective temperatures are lower than 6700K with periods in the range from 0.09 to 0.22 d. NDSTs have metallicity close to that of the Sun as expected, while UCVs are slightly metal poor than NDSTs. The two peaks on the distributions of the period and stellar atmospheric parameters are all caused by the existence of UCVs. When those UCVs are excluded, it is discovered that the effective temperature, the gravitational acceleration, and the metallicity all are correlated with the pulsating period for NDSTs and their physical properties and evolutionary states are discussed. Detection of those UCVs indicates that about 25 per cent of the known δ Scuti stars may be misclassified. However, if some of them are confirmed to be pulsating stars, they will be a new-type pulsator and their investigations will shed light on theoretical instability domains and on the theories of interacting between the pulsation and the convection of solar-type stars. Meanwhile, 88 δ Scuti stars are detected to be the candidates of binary or multiple systems. [ABSTRACT FROM AUTHOR]

We have fabricated Fibonacci [Co/Pt] multilayers with two constituent Co/Pt bilayers, as well as periodic multilayers of the same Co/Pt bilayers, all of which exhibit perpendicular magnetic anisotropy. Magnetic properties of the quasiperiodic and periodic [Co/Pt] multilayers have been studied macroscopically by vibrating sample magnetometry and microscopically by magnetic force microscopy. The Fibonacci [Co/Pt] multilayers show enhanced squareness in magnetic hysteresis loops compared to the corresponding periodic [Co/Pt]n multilayers, due to a smaller density of isolated nucleation sites in the saturation state. [ABSTRACT FROM AUTHOR]

Background: Induction of labour has become an increasingly common procedure. Ripening methods, including mechanical devices and pharmacological agents, improve the success rate of labour induction.Objective: To compare the efficacy and safety of the double-balloon catheter with prostaglandin E2 agents used for labour induction.Search Strategy: We searched electronic sources from MEDLINE, Embase and Web of Science, the Cochrane Library Database of Systematic Reviews, and ClinicalTrials.gov website.Selection Criteria: Only randomised controlled trials comparing the PGE2 agents with the double-balloon catheter for cervical ripening and labour induction in women with unfavourable cervices were included in the analysis.Data Collection and Analysis: The main outcomes included the vaginal delivery rate within 24 hours and risk of caesarean section. We calculated relative risks and mean differences using fixed- and random-effects models.Main Results: Nine studies (1866 patients) were included in this systematic review. Both the double-balloon catheter and PGE2 agents were comparable with regard to rate of caesarean section (RR 0.92; 95% CI 0.79, 1.07), vaginal delivery within 24 hours (RR 0.95; 95% CI 0.78, 1.16) and maternal adverse events, but the risk of excessive uterine activity (RR 10.02; 95% CI 3.99, 25.17) and need for neonatal intensive care unit admissions (RR 1.31; 95% CI 1.01, 1.69) were significantly increased in women who received PGE2 agents.Conclusions: The double-balloon catheter demonstrated greater safety and cost-effectiveness than PGE2 agents for cervical ripening and labour induction. The efficacy profiles of both methods were similar.Tweetable Abstract: Double-balloon catheter versus prostaglandin E2 for cervical ripening and labour induction. [ABSTRACT FROM AUTHOR]

OBJECTIVE: The present study was planned to evaluate the effect of light on the development of light-sensitive retinal ganglion cells. MATERIALS AND METHODS: The Sprague-Dawley (SD) rats were segregated into 3 groups (n=18) which included routine feeding 10-day group 1, routine feeding 14-day group 2 and light-deprivation feeding 14-day group 3. The group 1 animals were routinely fed for 10 days in normal light conditions and were sacrificed for analyses on day 10. Similarly, group 2 animals were routinely fed for 14 days in normal light conditions and were sacrificed for analyses on day 14. The group 3 animals were kept were routinely fed for 7 days which was followed by their feeding in a light-deprived conditions and were sacrificed on day 14. RESULTS: The expression of the opsin gene determined by real-time PCR in retinal tissues showed a significant decline in the light-deprived group 3 when compared to other two groups. Furthermore, the melanopsin protein also showed a significant decline in its protein expression in light-deprived group 3 as observed by immune-blot analyses. The immuno-fluorescence analyses also showed the similar trend confirming the effect of light on the development of retinal ganglion cells. CONCLUSIONS: Light is essential for the proper development process of retinal ganglion cells as light directly affects regulatory opsin gene expression. [ABSTRACT FROM AUTHOR]

A novel polyimide derivative is prepared by a condensation polymerization of pyromellitic dianhydride and 2,6-diaminoanthraquinone and a flexible electrode film –SWNT is further fabricated by filtration with single-walled carbon nanotube dispersions. connects different carbonyl groups of dianhydride and quinone together, therefore combining the advantages of different units together. Electrochemical tests show that –SWNT can transfer three electrons reversibly and theoretical calculations also prove that. –SWNT shows a high capacity of 190 mA h g−1 and superior rate performance, maintaining 120 mA h g−1 at 20C. –SWNT is a promising flexible electrode because of its good performance and flexibility. [ABSTRACT FROM AUTHOR]

We study the magnetocaloric effect and the critical behavior of a periodic Anderson-like organic polymer using Green's function theory, in which the localized f orbitals hybridize with the conduction orbitals at even sites. The field-induced metal–insulator transitions with the magnetic Grüneisen parameter showing ☋Γh☋∼T−1 power-law critical behaviour are revealed, which provides a new thermodynamic means for probing quantum phase transitions. It is found that the competition of up-spin and down-spin hole excitations is responsible for the double peak structure of magnetic entropy change (−ΔS) for the dominant Kondo coupling case, implying a double magnetic cooling process via demagnetization, which follows a power law dependence of the magnetic field h: −ΔS∼hn. The local exponent n tends to 1 and 2 below and above TC, while has a minimum of 0.648 at TC, which is in accordance with the experimental observation of perovskite manganites Pr0.55Sr0.45MnO3 and Nd0.55Sr0.45MnO3 (J. Y. Fan et al., Appl. Phys. Lett., 2011, 98, 072508; Europhys. Lett., 2015, 112, 17005) corresponding to the conventional ferromagnets within the mean field theory −ΔS∼h2/3. At TC, the −ΔS∼h curves with a convex curvature superpose each other for small V values, which are separated by the large V case, distinguishing the RKKY interaction and Kondo coupling explicitly. Furthermore, the critical scaling law n(TC) = 1 + (β− 1)/(β + γ) = 1 + 1/δ(1 − 1/β) is related to the critical exponents (β, γ, and δ) extracted from the Arrott–Noakes equation of state and the Kouvel–Fisher method, which fulfill the Widom scaling relation δ = 1 + γβ−1, indicating the self-consistency and reliability of the obtained results. In addition, based on the scaling hypothesis through checking the scaling analysis of magnetization, the M–T–h curves collapse into two independent universal branches below and above TC. [ABSTRACT FROM AUTHOR]

We study magnetotransport properties of the Si/Nb/Si trilayers, in which the thickness of niobium, d, changes from 1.1 ran to 50 nm, while the thickness of Si is fixed at 10 nm. The niobium films are amorphous for d < 4 nm, while in thicker films the alligned polycrystalline grains are formed. We observe that the Hall coefficient changes sign into negative in the films with d < 1.6 nm. We also find that in the ultrathin films the magnetic field induces a transition from the superconducting into a metallic phase with the resistance smaller than the normal-state resistance. [ABSTRACT FROM AUTHOR]

Using the magnetoresistance measurements we study the phase transition line and the activation energy for vortex pinning in superconductor/ferromagnet bilayer, built of a ferromagnetic Co/Pd multilayer with perpendicular magnetic anisotropy, and a niobium film, with insulating layer in-between to eliminate proximity effect. The domain width is reversibly pre-defined using the angle-dependent demagnetization. We find that the enhancement of the activation energy for vortex pinning by magnetic domains is rather modest, by a factor of about 2.1. We attribute this to large domain width, and large dispersion of the domain width in this bilayer. [ABSTRACT FROM AUTHOR]

A low-waste technology for the reprocessing of spent nuclear fuel (SNF) has been developed recently, which involves the conversion of actinide and lanthanide oxides with liquid N2O4 into their nitrates followed by supercritical fluid extraction of the nitrates. The possibility of the reprocessing of SNF from high-temperature gas-cooled reactors (HTGRs) with nitrate conversion and supercritical fluid extraction is a current area of research in China. Here, a UO2-CeO2 solid solution was prepared as a surrogate for a UO2-PuO2 solid solution, and the recovery of U and Ce from the UO2-CeO2 solid solution with liquid N2O4 and supercritical CO2 containing tri-n-butyl phosphate (TBP) was investigated. The UO2-CeO2 solid solution prepared by electrolytic reduction-coprecipitation method had square plate microstructures. The solid solution after heat treatment was completely converted into nitrates with liquid N2O4. The XRD pattern of the nitrates was similar to that of UO2(NO3)2 ·3H2O. After 120 min of online extraction at 25 MPa and 50 ℃, 99.98% of the U and 98.74% of the Ce were recovered from the nitrates with supercritical CO2 containing TBP. The results suggest a promising potential technology for the reprocessing of SNF from HTGRs. [ABSTRACT FROM AUTHOR]