Study on ablation behavior and mechanism of C/SiC composite irradiated by a laser with various parameters

C/SiC composite has been widely used as a high-temperature material for engineering components due to its excellent thermal properties. Facing the rapid development and threat of high-energy laser, study on the ablation resistance under laser irradiation is strongly required. In this work, a continuous high-energy laser was applied to explore the laser ablation behavior and mechanism of C/SiC composite. From the results, C/SiC composite shows different morphologies when irradiated at various laser power densities for 500 and 700 W/cm². We divided the ablation area into three regions; the central, transition, and edge regions, where the formation of SiO₂, SiO, and the breakage of carbon fiber were observed. The generated highly reflective SiO₂ layer reduces the absorption of laser energy, which is beneficial to lower the back-surface temperature and reduce the damage of composite. In addition, we put forward the ablation physical models and ablation mechanisms irradiated at different power densities. The work provides a basis for the laser ablation resistance of C/SiC composites under different conditions.     

Influence of Interferon-Alpha Combined with Chemo (Radio) Therapy on Immunological Parameters in Pancreatic Adenocarcinoma

Prognosis of patients with carcinoma of the exocrine pancreas is particularly poor. A combination of chemotherapy with immunotherapy could be an option for treatment of pancreatic cancer. The aim of this study was to perform an immunomonitoring of 17 patients with pancreatic cancer from the CapRI-2 study, and tumor-bearing mice treated with combination of chemo (radio) therapies with interferon-2α. Low doses of interferon-2α led to a decrease in total leukocyte and an increase in monocyte counts. Furthermore, we observed a positive effect of interferon-2α therapy on the dendritic cells and NK (natural killer) cell activation immediately after the first injection. In addition, we recorded an increased amount of interferon-γ and IL-10 in the serum following the interferon-2α therapy. These data clearly demonstrate that pancreatic carcinoma patients also show an immunomodulatory response to interferon-2α therapy. Analysis of immunosuppressive cells in the Panc02 orthotopic mouse model of pancreatic cancer revealed an accumulation of the myeloid-derived suppressor cells in spleens and tumors of the mice treated with interferon-2α and 5-fluorouracil. The direct effect of the drugs on myeloid-derived suppressor cells was also registered in vitro. These data expose the importance of immunosuppressive mechanisms induced by combined chemo-immunotherapy.     

A discharge-based periodic pulse hollow-cathode generator and an antenna system for emitting high-power radio pulses

A discharge-based generator with a hollow cathode and an emitting system based on a corner antenna for emitting a periodic high-power high-frequency radio pulse train were developed and tested. The parameters of generated and emitted radio pulses are as follows: (i) the carrier frequency is 120 MHz, (ii) the peak power is 300 kW, (iii) the pulse duration is 1.2 μs, and (iv) the pulse repetition rate is 500 Hz.     

The theory of ion-sound solitons in plasma with electrons featuring the Tsallis distribution

A solution to a problem concerning the structure of a nonlinear ion-sound soliton in a plasma with electrons featuring the Tsallis distribution has been found. The smaller the parameter q (characterizing the degree of deviation of the electron distribution from the Maxwell-Boltzmann law), the greater the possible liming (breakage) Mach number of the soliton and the greater the soliton width.     

Exact integral-free expressions for the integral Debye functions

Exact explicit integral-free expressions for the integral Debye functions and an integral-free expression for the heat capacity of the k-dimensional crystal lattice as a function of the temperature are obtained for the first time. The expressions involve polylogarithms and the Riemann zeta function.     

A Mechanical-and-Kinetic Effect in a Weakly Ionized Low-Pressure Plasma

A new mechanical-and-kinetic effect is revealed under conditions of interaction between ions of a weakly ionized plasma of a low-pressure discharge and the surface of a solid. The effect consists in that a plate placed in the plasma (on condition that a coating is applied to the plate) is acted upon by a force proportional to the difference between the probabilities of elastic reflection of ions from its surfaces. The revealed effect may be used for measuring this difference.