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CrP has many exotic physical properties due to a four-fold degenerate band crossing at the Y point of the Brillouin zone, which is protected by the nonsymmorphic symmetry of the space group. We carried out the heat capacity, the electrical and thermal transport measurements on CrP and extracted the electron thermal conductivity. Due to the difference in energy and momentum relaxation time during electron-phonon inelastic scattering, the normalized Lorentz number decreases below about 160 K. Below 25.6 K, the normalized Lorentz number begins to recover, which is due to the dominance of elastic scattering between electrons and defects at low temperatures.

The braking indices of pulsars may contain important information about the internal physics of neutron stars (NSs), such as neutron superfluidity and internal magnetic fields. As a subsequent paper of Cheng et al., we perform the same analysis as that done in the previous paper to other young pulsars with a steady braking index, n. Combining the timing data of these pulsars with the theory of magnetic field decay, and using their measured magnetic tilt angles, we can set constraints on the number of precession cycles, ξ, which represents the interactions between superfluid neutrons and other particles in the NS interior. For the pulsars considered in this paper, the results show that ξ is within the range of a few ×103 to a few ×106. Interestingly, for the Crab and Vela pulsars, the constraints on ξ obtained with our method are generally consistent with that derived from modeling of the glitch rise behaviors of the two pulsars. Furthermore, we find that the internal magnetic fields of pulsar with n < 3 may be dominated by the toroidal components. Our results may not only help to understand the interactions between the superfluid neutrons and other particles in the interior of NSs but also be important for the study of continuous gravitational waves from pulsars.

The observed electromagnetic radiation from some long and short gamma-ray bursts, and neutron stars (NSs), and the theoretical models proposed to interpret these observations together point to a very interesting but confusing problem, namely, whether fall-back accretion could lead to dipole field decay of newborn NSs. In this paper, we investigate the gravitational wave (GW) radiation of newborn magnetars with a fall-back disk formed in both the core-collapse of massive stars and the merger of binary NSs. We make a comparison of the results obtained with and without fall-back accretion-induced dipole-field decay (FADD) involved. Depending on the fall-back parameters, initial parameters of newborn magnetars, and models used to describe FADD, FADD may indeed occur in newborn magnetars. Because of the low dipole fields caused by FADD, the newborn magnetars will be spun up to higher frequencies and have larger masses in comparison with the non-decay cases. Thus the GW radiation of newborn accreting magnetars would be remarkably enhanced. We propose that observation of GW signals from newborn magnetars using future GW detectors may help to reveal whether FADD could occur in newborn accreting magnetars. Our model is also applied to the discussion of the remnant of GW170817. From the post-merger GW searching results of Advanced LIGO and Advanced Virgo we cannot confirm the remnant is a low-dipole-field long-lived NS. Future detection of GWs from GW170817-like events using more sensitive detectors may help to clarify the FADD puzzle.

Rotochemical heating originates in the deviation from beta equilibrium due to spin-down compression, which is closely related to the dipole magnetic field. We numerically calculate the deviation from chemical equilibrium and thermal evolution of neutron stars with decaying magnetic fields. We find that the power-law long term decay of the magnetic field slightly affects the deviation from chemical equilibrium and surface temperature. However, the magnetic decay leads to older neutron stars that could have a different surface temperature with the same magnetic field strength. That is, older neutron stars with a low magnetic field (108 G) could have a lower temperature even with rotochemical heating in operation, which probably explains the lack of other observations on older millisecond pulsars with higher surface temperature, except millisecond pulsar J0437–4715.

Using a realistic equation of state (EOS) of strange quark matter, namely, the modified bag model, and considering the constraints to the parameters of EOS by the observational mass limit of neutron stars, we study the r-mode instability window of strange stars, and find the same result as the brief study of Haskell, Degenaar and Ho in 2012 that these instability windows are not consistent with the spin frequency and temperature observations of neutron stars in LMXBs., Comment: 8 pages,4 figures

We obtain analytically the static states and corresponding collective-excitation spectra of a quasi-one-dimensional spin-1 condensate modulated by a long-wavelength optical lattice in the weak lattice limit. It is demonstrated that both ferromagnetic and antiferromagnetic condensates may exhibit dynamical instability, which agree with the results with numerical simulation. In the homogeneous limit, our results reduce to the previous results for homogeneous spinor condensates, i.e., dynamical instability can occur only for ferromagnetic interaction and an antiferromagnetic condensate is always dynamically stable.

The braking index is an important factor when examining the pulsar braking mechanism. Measuring braking indices requires measuring the pulsar period and its first and second derivatives. Among them, the second derivative is easily contaminated by timing noise and an unresolved glitch effect. The absence of data bounding a given transition into (or out of) a radio-on phase is another disadvantage in measuring the second derivatives of intermittent pulsars, as was recently demonstrated by Young and coworkers. But, the observed period first derivatives, in the "on" and "off" states of the intermittent pulsars, give us a possible way to predict their braking indices even though they are hard to observe. In this paper, we will give a simple and useful method to study the braking indices of intermittent pulsars. As an application of our method, we will calculate the possible braking indices of three intermittent pulsars and one nulling pulsar, namely, PSR B1931 + 24, PSR J1841 0500, PSR J1832 + 0029 and PSR B0823 + 26, under three different magnetospheric conditions, which include polar cap size variation, charge density variation and the combination of the above two cases. We have found that all the braking indices we predicted are almost within the observed domain It is concluded that, in a relatively short observation period, in which the variation of the braking index can be ignored, we can accurately predict the braking indices of intermittent pulsars, under a specific magnetosphere model, by using the observed "on" and "off" state period first derivatives.

The ground states of the ultracold spin-1 atoms trapped in a deep one-dimensional double-well optical superlattice in a weak magnetic field are obtained. It is shown that the ground-state diagrams of the reduced double-well model are remarkably different for the antiferromagnetic and ferromagnetic condensates. The transition between the singlet state and nematic state is observed for the antiferromagnetic interaction atoms, which can be realized by modulating the tunneling parameter or the quadratic Zeeman energy. An experiment to distinguish the different spin states is suggested.

Interstellar scattering causes broadening and distortion to the mean pulse profiles and polarization position angle (PPA) curves, especially to the pulse profiles observed at lower frequency. This paper has implemented a method to recover the pulse profiles and the PPA curves of five pulsars which have obvious scattered pulse profiles at lower frequency. It reports a simulation to show the scattering and descattering of pulse profiles and PPA curves. As a practical application, lower-frequency profiles and PPA curves of PSR 1356-60, PSR 1831-03, PSR 1838+04, PSR 1859+03, PSR 1946+35 are obtained. It is found that the original pulse profiles and PPA curves can be recovered., 9 pages, 6 figures, accepted for publication in RAA

Electrochemical discharge machining (ECDM) is found to be a potential process for the microdrilling of glass wafers. However, some degree of heat-affected zone resulting from the thermal energy during ECDM produces several inherent problems that might be major issues, such as over cut and taper hole. To improve the quality of the ECDM microhole, a flat sidewall–flat front tool electrode is designed to reduce taper phenomena due to the sidewall discharge. In addition, a pulse voltage is applied to improve the heat-affected zone in the rectified dc voltage. The experimental results show that the combination of flat sidewall–flat front tool and pulse voltage conspicuously increases the machining accuracy while retaining the machining rate. This experimental investigation provides a new method that overcomes the disadvantages of conventional ECDM.

A Monte Carlo simulation, with the energetics described by the embedded atom method, has been employed to study the physical behaviour of boron atoms during relaxation of the Ni3AlBinfinity grain boundary. It has also been used to calculate not only the peak concentrations of Ni and B and the valley concentration of Al at the grain boundary, but also the dependence of the grain boundary cohesion on the B bulk concentration. During relaxation of impure Ni3Al grain boundaries, we suggest that, as the segregating species, the B atoms either insert into interstices in the grain boundary or substitute Ni atoms. Meanwhile, as the inducing species, they induce Ni atoms to substitute for Al atoms. Calculations show that in the equilibrium, when the B bulk concentration x increases from 0.1 to 0.9, the peak concentration of B increases, the peak concentration of Ni maximizes while the valley concentration of Al minimizes at x = 0.5. The calculations also show the best cohesion of the grain boundary at x = 0.5.

We calculate the mass-radius relationship of quark stars with the magnetized density-dependent quark mass model in this work, considering two magnetic field geometries: a statistically isotropic, tangled field and a force-free configuration. In both cases, magnetic field production decreases in the case of maximum quark star mass. Furthermore, a tangled, isotropic magnetic field has a relatively smaller impact on the mass and radius, compared to the force-free configuration, which implies that the geometry of the interior magnetic field is at least as important as the field strength itself when the influence of the strong magnetic field on the mass and radius is assessed.

Manganese monophosphide (MnP) shows complicated magnetic states varying with both temperature and pressure. We calculate the magnetic and electronic structures of MnP at different pressures using first-principles methods and obtain spiral ground states whose propagation vector changes from the c-axis at low pressure to the b-axis at high pressure. In between, we find a ferromagnetic state, as observed in the experimental phase diagram. The propagation vector of the spiral states is found to vary nonmonotonically with pressure, consistent with neutron measurements. Our results indicate that the complicated magnetic phase diagram originates from a delicate competition between neighboring exchange interactions between the Mn-ions. At all pressures, the electronic structures indicate the existence of quasi-one-dimensional charge carriers, which appear in the ferromagnetic state and become gapped in the spiral state, and anisotropic three-dimensional charge carriers. We argue that this two-fluid behavior originates from the special crystal structure of MnP and may be relevant for understanding the pairing mechanism of the superconductivity at the border of the high pressure spiral phase., Comment: 8 pages, 6 figures, 2 tables

We present an integrated mathematical model of vehicle-following control for the establishment, maintenance, and re-establishment of the previous or new safe and efficient steady-following state. The hyperbolic functions are introduced to establish the corresponding mathematical models, which can describe the behavioral adjustment of the following vehicle steered by a well-experienced driver under complex vehicle following situations. According to the proposed mathematical models, the control laws of the following vehicle adjusting its own behavior can be calculated for its moving in safety, efficiency, and smoothness (comfort). Simulation results show that the safe and efficient steady-following state can be well established, maintained, and re-established by its own smooth (comfortable) behavioral adjustment with the synchronous control of the following vehicle's velocity, acceleration, and the actual following distance.

The energy variation of a parton passing through a quark-gluon plasma(QGP) is discussed by taking into account nonlinear polarization effect. It is found that the parton can be accelerated by fluctuations in QGP, which gives a new physical insight about the response of QGP to such external current.

Recently, the utilization of pulse voltage has proved to be a potential method for improving the machining accuracy in the microdrilling process by electrochemical discharge machining (ECDM). Although pulse voltage is favorable for improving the machining quality, it is hard to obtain an efficient machining rate. The pulse-off (Toff) duration allows the gas film structure to be re-constructed, which makes the sustainability of a dense gas film difficult and results in unstable and unpredictable discharges. In this study a novel pulse voltage configuration, called offset pulse voltage, has been designed and applied in the ECDM process to improve gas film stability. The offset pulse voltage adds a constant voltage, called offset voltage, at Toff duration to enhance gas film stability and to further promote the discharge performance. The experimental results demonstrated that the increase in offset voltage at the pulse-off duration generates more stable discharges when compared to those generated by the conventional pulse voltage. Results also show that both the mean machining time and time deviation are decreased around 60% without sacrificing machining accuracy by an adequate offset voltage.