The effect of the strong external magnetic field is studied on the dielectric Cherenkov maser, which is included with an axial thin annular relativistic electron beam and a plasma column in a dielectric lined slow-wave waveguide. The dispersion equations of the beam-wave interaction are derived. The growth rates of the wave are obtained, and the effects of the accelerating voltage, beam current and the background plasma density on the growth rate of the wave are numerically calculated, discussed, and compared in the presence and absence of external magnetic field.

Unfavorable environmental conditions during planting can reduce seed germination and hinder seedling growth. To address this issue, manufacturers are exploring innovative and cost-effective methods, such as cold plasma discharge. This simple, low-cost, and efficient physical technique induces significant biological responses in seeds and plants without the use of traditional, environmentally hazardous chemicals. This study investigated the impact of dielectric barrier discharge (DBD) plasma and plasma-activated water (PAW), produced by gliding arc plasma, on the germination and seedling growth of My344 cotton seeds. The seeds were pre-treated with 80 W of DBD plasma for 0, 1, 2, and 3 min, and subsequently soaked for 90 min in PAW with varying pH levels of 5.82, 3.88, 3.63, and 3.38. The results showed that plasma treatment positively influenced seed germination and seedling growth. The highest germination percentage (98.89 %) was observed with 1 min of DBD treatment, followed by PAW priming at pH levels of 3.63 and 3.38. Additionally, a 3-min DBD treatment followed by soaking in PAW with a pH of 3.63 led to significant increases in stem length (76.76 %), root length (48.77 %), and wet weight (76.44 %). Furthermore, it was observed that the electrical conductivity of the seeds in all groups decreased significantly with increased PAW acidity. The physical and chemical effects of cold DBD plasma on the seed surface, as well as changes in hydrophilicity, were further examined using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), and water contact angle imaging.

In this research, a systematic investigation of the properties of stoichiometric ultra-high temperature ceramics Z r x T a 8 − x C 8 is carried out. The mechanical properties including elastic constants, shear modulus, bulk modulus, Zener ratio, Poisson ratio, Pugh’s index are calculated and then the hardness (H) and H 3 / E 2 based on a semi-empirical approach are estimated. It exhibits that TaC possesses the lowest hardness equal to 22 GPa that increases to maximum hardness 30 GPa when a single Zr atom is substituted with Ta ( Z r 1 T a 7 C 8 ) . Afterwards, the partial density of states (PDOS) of mentioned ceramics was calculated and plotted. Since the density of states at the Fermi level has some value, it is inferred that they all are electrical conductors. The p-d hybridization, the states at the Fermi level and the Mulliken charges of each atom indicate that the covalent, metallic and ionic nature of bonding exist simultaneously among constituent elements.

Plasma treatment of polymeric materials is a cost-effective and efficient technique to modify the surface and change the constituent unit configuration. This research investigates the effects of argon DC glow discharge plasma on pure and DR1 dye-loaded polyamide 6 polymer films and stabilization of dye on the surface. Plasma breaks some bonds and activates the surface through creating reactive structures such as free radical sites on the surface and increases tertiary amides on the surface of polymer. Besides, this process alters surface topographical characteristics and conformation of azobenzene dye which are effective on the durability of the dye on the surface. Plasma causes interactions of the dye with the polymer and immobilizes the dye on the polymer. On the other hand, these interactions lead to changes in the dye's optical and geometric isomeric activity and stability. This work studies the chemical and morphological changes of polyamide 6 by plasma with AFM and spectroscopic methods. Furthermore, the aging of nylon 6 films loaded with DR1 dye is measured, and the conformational changes of the dye are investigated. Plasma stabilizes the dye on the polymer surface through making changes of chemical and physical properties on the surface components.