There have been limited studies addressing the thermally dependent mechanical properties of skin tissue, although this can contribute to a variety of medical applications. To address this, an experimental study on the tensile behaviour of pig skin tissue under different thermal loading conditions and different mechanical stretching rates was performed. The results indicate that there is a significant variation among skin tensile behaviours under different temperatures and loading rates, which is correlated with dermal collagen denaturation. The Ogden model was used to summarize the effect of the strain rate and the temperature upon the measured constitutive response through two parameters (α and μ). These results can be used in future models to improve clinical thermal treatments for skin tissue.

Tungsten has been widely used in many industrial fields due to its excellent properties. However, owing to its characteristics of inherent brittleness at room temperature and high melting point, it is difficult to prepare tungsten parts with high complexity via traditional methods. In the present work, tungsten samples were prepared by laser powder bed fusion. The influence of each process parameter including laser power, scanning speed, and hatch spacing on the surface morphology, densification, and microstructure of tungsten samples was systematically investigated. The results showed that the use of the appropriate parameters, especially high laser power, can effectively improve the surface quality and obtain a dense surface. The tungsten samples with a relative density of 98.31% were obtained with optimized parameter combinations: a laser power of 300 W, scanning speed of 400 mm/s, and hatch spacing of 0.08 mm. Compared with scanning speed and hatch spacing, the laser power had a more obvious influence on the relative density. Additionally, for the grain morphology by microstructure inspection, elongated curved grains gradually transformed into fine straight columnar grains as the scanning speed increased. The hatch spacing would change the grain morphology slightly but had no significant effect on the grain size.

Aims. Nonthermal radiation properties of pulsar wind nebulae (PWNe) are studied in the frame of a time-dependent model with particle advection and diffusion. Methods. The dynamical and radiative evolution of a PWN was self-consistently solved in the model. The time-dependent lepton (electrons and positrons) equation is described by particle injection, advection, diffusion, adiabatic loss, and radiative loss. Nonthermal emission from a PWN is mainly produced by the relativistic leptons through synchrotron radiation and inverse Compton process. Results. The effect of particle transport including advection and diffusion was analyzed, showing that the particle transport process induces a decrease in the nebula flux, and that the total flux decreases with the increase in advection velocity and diffusion coefficient. Meanwhile, the particle transport processes may play an important role in modifying the spectrum of the emitted radiation at X-ray and TeV wavelengths, but only have slightly effects in radio and GeV bands. We applied our model to the three PWNe Crab nebula, 3C 58, and G54.1+0.3, and observed that the spectral energy distributions of photon emissions from the three PWNe are reproduced well. Our results indicate that (i) the particle cooling processes are dominated by adiabatic loss in lower-energy bands and synchrotron loss dominates for the higher-energy particles; and (ii) the particle transport processes are advection dominated, and a slow diffusion may occur within the Crab nebula, 3C 58, and G54.1+0.3.

Orion KL is one of the prime templates of astrochemical and prebiotic chemical studies. We wish to explore more organic molecules with increasing complexity in this region. In particular, we have searched for one of the most complex organic molecules detected in space so far, ethyl formate (C 2 H 5 OCHO). This species is the next step in chemical complexity after the simplest member of esters (methyl formate, CH 3 OCHO). The mechanisms leading to its formation are still poorly known. We have used high angular resolution (∼ 1. ′′ 5) ALMA observations covering a large bandwidth from 214 to 247 GHz. We have detected 82 unblended lines of C 2 H 5 OCHO (49 and 33 of the trans and gauche conformers, respectively). The line images showed that C 2 H 5 OCHO arises mainly from the compact ridge and the hot core-southwest regions. The derived rotational temperatures and column densities are 122 ± 34 K, (0.9 ± 0.3) × 10 16 cm −2 for the hot core-SW, and 103 ± 13 K, (0.6 ± 0.3) × 10 16 cm −2 for the compact ridge. The comparison of spatial distribution and abundance ratios with chemically related molecules (methyl formate, ethanol and formic acid) indicates that C 2 H 5 OCHO is likely formed on the surface of dust grains by addition of CH 3 to functional-group radicals (CH 2 OCHO) derived from methyl formate (CH 3 OCHO).