Subjective well-being among PhD students in mainland China: the roles of psychological capital and academic engagement

The mental well-being of PhD students is a major concern in higher education. However, very few studies have investigated the influencing factors of PhD students’ subjective well-being (SWB) – an important indicator of mental well-being. Even no study on the influencing factors of PhD students’ SWB has been undertaken in mainland China. Based on job demands–resources theory, the present study pioneers the investigation of the relationship between PhD students’ psychological capital (PsyCap; comprising self-efficacy, hope, resilience, and optimism) and SWB (comprising positive affect, negative affect, and life satisfaction) in mainland China. It further examined the mediating role of academic engagement (comprising vigor, dedication, and absorption) in this relationship. PhD students (n = 376) from two comprehensive universities in Jiangsu province responded to an online survey. The results showed that (1) self-efficacy was positively associated with life satisfaction, hope was positively associated with positive affect, optimism was significantly associated with all three dimensions of SWB, but resilience was not significantly associated with any of the three SWB dimensions; and (2) dedication mediated the relationship between hope and life satisfaction and that between optimism and negative affect and life satisfaction, but vigor and absorption did not mediate any of the PsyCap–SWB relationships. Limitations and practical implications of this study are discussed

Radio pulsar B0950++08: Radiation in Magnetosphere and Sparks above Surface

The nearby radio pulsar B0950$+$08 with full duty cycle is targeted by the Five-hundred-meter Aperture Spherical radio Telescope (FAST, 110 minutes allocated), via adopting polarization calibration on two ways of baseline determination, in order to understand its magnetospheric radiation geometry as well as the polar cap sparking. % The radiation of the main pulse could not be informative of magnetic field line planes due to its low linear polarization ($<10 \%$) and the position angle jumps, and the polarization position angle in the pulse longitudes whose linear fractions are larger than $\sim 30 \%$ is thus fitted in the classical rotating vector model (RVM). % The best RVM fit indicates that the inclination angle, $\alpha$, and the impact angle, $\beta$, of this pulsar are $100.5^{\circ}$ and $-33.2^{\circ}$, respectively, suggesting that the radio emission comes from two poles. % Polar cap sparking in the vacuum gap model, either the annular gap or the core gap, is therefore investigated in this RVM geometry, resulting in a high-altitude magnetospheric emission at heights from $\sim 0.25R_{\rm LC}$ to $\sim 0.56R_{\rm LC}$, with $R_{\rm LC}$ the light cylinder radius. % It is evident that both sparking points of the main and inter pulses are located mainly away from the magnetic pole, that is meaningful in the physics of pulsar surface and is even relevant to pulsar's inner structure.Comment: 13 pages, 9 figures, submitte

PSR B0943+10: Mode Switch, Polar Cap Geometry, and Orthogonally Polarized Radiation

As one of the paradigm examples to probe into pulsar magnetospheric dynamics, PSR B0943+10 (J0946+0951) manifests representatively, showing mode switch, orthogonal polarization and subpulse drifting. Both integrated and single pulses are studied with the Five-hundred-meter Aperture Spherical radio Telescope (FAST). The mode switch phenomenon of this pulsar is studied using an eigen-mode searching method, based on parameter estimation. A phase space evolution for the pulsar's mode switch shows a strange-attractor-like pattern. The radiative geometry is proposed by fitting polarization position angles with the rotating vector model. The pulsar pulse profile is then mapped to the sparking location on pulsar surface, and the differences between the main pulse's and the precursor component's radiative process may explain the X-ray's synchronization with radio mode switch. Detailed single pulse studies on B0943+10's orthogonally polarized radiation are presented, which may support for certain models of radiative transfer of polarized emission. B0943+10's B and Q modes evolve differently with frequency and with proportions of orthogonal modes, which indicates possible magnetospheric changes during mode switch. An extra component is found in B mode, and it shows distinct polarization and modulation properties compared with main part of B mode pulse component. For Q mode pulse profile, the precursor and the main pulse components are orthogonally polarized, showing that the precursor component radiated farther from the pulsar could be radiated in O-mode (X-mode) if the main pulse originates from low altitude in X-mode (O-mode). The findings could impact significantly on pulsar electrodynamics and the radiative mechanism related.Comment: 27 pages, 28 figures, 2 tables, submitted to Ap

Complete mitochondrial genome of Rusa unicolor cambojensis (Artiodactyla: Cervidae)

Rusa unicolor has been listed as a vulnerable species by the International Union for Conservation of Nature and Natural Resources because of human activities. In recent years, population numbers have decreased due to heavy hunting and habitat loss, and little genetic data on this species exists; thus, our knowledge of range distribution and population size remains limited. In the current study, the complete R. u. cambojensis mitochondrial genome was sequenced using polymerase chain reaction followed by direct sequencing. The complete mitochondrial genome was determined to be circular and contain 16,557 bp, including 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and 1 control region, the gene composition and order were similar to those of most other vertebrates reported to date. Most mitochondrial genes, except for ND6 and eight tRNAs, were encoded on the heavy strand. The overall base composition of the heavy strand was 33.6% A, 28.9% T, 24.2% C, and 13.3% G, with a strong AT bias of 62.5%. There were 13 regions of gene overlap totaling 96 bp and 12 intergenic spacer regions totaling 70 bp. The phylogenetic analyses (maximum likelihood and Bayesian inference) of R. unicolor based on the mitochondrial genome four subspecies of R. unicolor were clustered into a well-supported single clade, and R. u. cambojensis was most closely related to R. u. dejeani. This study will assist in the exploration of the evolutionary history and taxonomic status of the sambar, as well as its protection as a genetic resource

Simulation of the Particle Transport Behaviors in Nanoporous Matter

The transport behaviors of proton into nanoporous materials were investigated using different Monte Carlo simulation codes such as GEANT4, Deeper and SRIM. The results indicated that porous structure could enhance the proton scattering effects due to a higher specific surface area and more boundaries. The existence of voids can deepen and widen the proton distribution in the targets due to relatively lower apparent density. Thus, the incident protons would transport deeper and form a wider Bragg peak in the end of the range, as the target materials are in a higher porosity state and/or have a larger pore size. The existence of voids also causes the local inhomogeneity of proton/energy distribution in micro/nano scales. As compared, the commonly used SRIM code can only be used to estimate roughly the incident proton range in nanoporous materials, based on a homogeneous apparent density equivalence rule. Moreover, the estimated errors of the proton range tend to increase with the porosity. The Deeper code (designed for evaluation of radiation effects of nuclear materials) can be used to simulate the transport behaviors of protons or heavy ions in a real porous material with porosity smaller than 52.3% due to its modeling difficulty, while the GEANT4 code has shown advantages in that it is suitable and has been proven to simulate proton transportation in nanoporous materials with porosity in its full range of 0~100%. The GEANT4 simulation results are proved consistent with the experimental data, implying compatibility to deal with ion transportation into homogeneously nanoporous materials

The Discharge Behavior and Mechanism of Polyimide Aerogel under Electron Irradiation

The response and mechanism of polyimide aerogel under electron irradiations were investigated. The experimental results indicated that electron irradiation could not damage the skeleton polyimide in the aerogel due to its high stability, but could result in a discharge within. The morphology of the discharge shows some dendritic discharge patterns, and the material surrounding the discharge channels was carbonized. The numerical simulation results indicated that the incident electrons, and also large amount induced secondary electrons, would be deposited inhomogeneously within the nano-porous polyimide aerogel. This would result in forming an ultra-high electrical potential of up to about 8.5 × 1010 V/m (which is far higher than the breakdown strength (2 × 108 V/m) of bulk polyimide materials) in a local region. This may be the leading cause of the obvious discharge in the materials. Furthermore, it was found that the actual reason for the discharge is related to the residual gas within the nano-porous structure; namely, the more internal residual gas (as a shorter-time vacuum pumping in the irradiated chamber), the more serious the discharge phenomenon. Correspondingly, the phenomenon may largely consist of both residual-gas discharge and surface flashover due to ultra-high local potentials induced by unevenly deposited charges in the porous aerogel

Radio Pulsar B0950+08: Radiation in the Magnetosphere and Sparks above the Surface

We observed the nearby radio pulsar B0950+08, which has a 100% duty cycle, using the Five-hundred-meter Aperture Spherical Radio Telescope. We obtained the polarization profile for its entire rotation, which enabled us to investigate its magnetospheric radiation geometry and the sparking pattern of the polar cap. After we excluded part of the profile in which the linear polarization factor is low (≲30%) and potentially contaminated by jumps in position angle, the rest of the swing in polarization position angle fits a classical rotating vector model (RVM) well. The best-fit RVM indicates that the inclination angle, α , and the impact angle, β , of this pulsar, are 100.°5 and −33.°2, respectively, suggesting that the radio emission comes from two poles. We find that, in such RVM geometry, either the annular vacuum gap model or the core vacuum gap model would require that the radio emissions come from a high-altitude magnetosphere with heights from ∼0.25 R _LC to ∼0.56 R _LC , with R _LC being the light cylinder radius. Both the main and interpulses’ sparking points are located away from the magnetic pole, which could relate to the physical conditions on the pulsar surface