Longitudinal optical conductivity of graphene in van der Waals heterostructures composed of graphene and transition metal dichalcogenides

Placing and twisting graphene on transition metal dichalcogenides (TMDC) forms a van der Waals (vdW) heterostructure. The occurrence of Zeeman splitting and Rashba spin-orbit coupling (SOC) changes graphene's linear dispersion and conductivity. Hence, this paper studies the dependence of graphene's longitudinal optical conductivity on Rashba SOC, the twist-angle and temperature. At zero temperature, a main conductivity peak exists. When Rashba SOC increases, a second peak occurs, with both extremes presenting an enhanced height and width, and the frequencies where the two peaks arise will increase because the energy gap and the possibility of electron transition increase. Altering the twist-angle from 0 to 30$^{\circ}$, the conductivity is primarily affected by chalcogen atoms. Moreover, when temperature increases to room temperature, besides a Drude peak due to the thermal excitation, a new band arises in the conductivity owing to the joint effect of the thermal transition and the photon transition.Comment: 17 pages, 13 figure

Structural Damage Identification of Pipe Based on GA and SCE-UA Algorithm

Structure of offshore platform is very huge, which is easy to be with crack caused by a variety of environmental factors including winds, waves, and ice and threatened by some unexpected factors such as earthquake, typhoon, tsunami, and ship collision. Thus, as a main part of the jacket offshore platform, pipe is often with crack. However, it is difficult to detect the crack due to its unknown location. Genetic algorithm (GA) and SCE-UA algorithm are used to detect crack in this paper, respectively. In the experiment, five damages of the pipe in the platform model can be intelligently identified by genetic algorithm (GA) and SCE-UA. The network inputs are the differences between the strain mode shapes. The results of the two algorithms for structural damage diagnosis show that both of the two algorithms have high identification accuracy and good adaptability. Furthermore, the error of SCE-UA algorithm is smaller. The results also suggest that the structural damage of pipe can be identified by intelligent algorithm

Effect of Homogenization Pressure on the Stability and in Vitro Digestion of Flaxseed Oil Emulsion

In this study, flaxseed oil body was taken as the research object, and stable flaxseed oil body emulsion rich in α-linolenic acid was obtained through homogenization treatment, which provides a new way for residents to increase the intake of ω-3 unsaturated fatty acids in daily diet. Under the same homogenous conditions (3 min) each time, changing the homogenization pressure (40, 80, 120 MPa) and the number of times (1~3 times) of flaxseed oil emulsions, the effects of homogenization on the properties, environmental stability ( pH, ionic strength, thermal, oxidation stability) and storage stability, and digestive properties of flaxseed oil emulsions were investigated. The results showed that the absolute value of potential zeta potential increased and the particle size decreased significantly when flaxseed oil body was homogenized at 120 MPa for three times (P0.05). The results of digestion showed that the homogenized flaxseed oil body emulsion had a higher release rate of fatty acids (FFA). In conclusion, the homogenization treatment significantly reduced the particle size of flaxseed oil emulsion, enhanced the storage stability and oxidation stability of flaxseed oil body, and accelerated the release rate of fatty acid