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In order to study the influence of the plasma actuator on the air flow in more detail, the effect of the plasma actuator on the flow field was simplified to the volume force of the electric field. Reynolds Average Navier-Stokes method and transition SST turbulence model were used to simulate the air flow field at different loading voltage, power frequency and inflow velocity. The results show that the higher the loading voltage and power frequency of the plasma actuator, the stronger the effect of the actuator on the flow field. The induced velocity increases non-linearly with increasing loading voltage, however, the increasing rate is getting slower and slower. When the voltage rises to about 30 kV, the acceleration effect of the actuator to air reaches the limit. The induced velocity increases linearly with the increase of the power frequency, but the change of the power frequency does not affect the operating range of the actuator in the vertical direction. Provided that parameters such as loading voltage and power frequency are constant, the higher the inflow velocity, the weaker the actuator’s effect on the flow field. And the higher velocity inflow obviously suppresses the range of the actuator in the vertical direction. [ABSTRACT FROM AUTHOR]

The thermal transport behavior of polycrystalline graphene is studied using molecular dynamics simulations, with focus on the effects of grain size, tensile strain, and temperature on the thermal conductivity. All the simulation samples have the same overall dimensions of 30×30 nm with average grain sizes ranging from 2.5 to 12.5 nm. It is found that polycrystalline graphene exhibits a significant reduction in thermal conductivity compared to single-crystalline graphene, and the smaller the grain size is, the more the thermal conductivity drops. The thermal conductivity of polycrystalline graphene with average grain size of 2.5 nm is only about 20% of single-crystalline graphene. However, the thermal conductivity of polycrystalline graphene is less sensitive to both the applied strain and temperature than that of single-crystalline graphene. The underlying mechanisms for the differences in thermal behavior are examined and discussed. These findings are important for the thermal management of graphene-based devices. [ABSTRACT FROM AUTHOR]

Tungsten heavy alloy is a kind of two-phase alloy composed of highstrength tungsten phase and binder phase with good-plasticity. Its mechanical properties and damage evolution are affected by both phases. The static and dynamic mechanical tests of 92.5W-4.9Ni-2.1Fe-0.5Co are carried out. According to the characteristics of stress-strain curves, KHL model is selected as the constitutive model of the material. Then, combined with Eshelby equivalent inclusion theory and Mori Tanaka mean field theory, the stress-strain relationship of each phase in tungsten heavy alloy is studied by introducing representative volume element (RVE). The damage evolution model considering the strain rate effect is proposed, and according to the different loading states, a two-phase constitutive model with damage is established. By compiling the UMAT subroutine, the test conditions of different strain rates are calculated in ABAQUS software. The simulation results are in good agreement with the test results, and the validity of the proposed model is verified. [ABSTRACT FROM AUTHOR]

Siberian wildrye (Elymus sibiricus L.) is widely cultivated in the central and western regions of China. It is an important agricultural produce and utilized in animal feed and is also important for ecological environment protection. It is of great significance for the preservation and production of germplasm resource to elucidate the seed aging mechanism, such as delaying seed aging, prolonging seed life as well as repairing seed vigor. Information on seed aging including aging conditions, physiological and biochemical characteristics, damage to genomic DNA and genetic integrity of germplasm resource is limited but necessary for germplasm collection, conservation and effective commercial use. However, it is rarely reported on the transcriptome analysis of seed aging in Siberian wildrye. In this study, we analyzed the differentially accumulated TDF (Transcript-Derived Fragments) by cDNA-AFLP technique using 136 pairs primers, a total of 653 TDFs were identified. These up-regulated TDFs were picked for sequence alignment and functional analysis. The results showed that the sequences of TDFs are highly homologous in plants, which are pyruvate kinase, metal transport protein, DNA damage repair protein, lectin receptor kinase, and leucine zip transcription factor. Additionally, chloroplast structure was destroyed and energy consumption was increased in seed aging, at the same time, it could resist aging by increasing transcripts of relevant defense genes transporter genes and corresponding DNA damage repair genes when Siberian wildrye is aged. The purpose of this study was to provide a theoretical basis for revealing the potential aging mechanism of Siberian wildrye from the transcriptional level. [ABSTRACT FROM AUTHOR]

Recently, nanoglass (NG) was found to exhibit a surprising homogeneous superplastic deformation behavior. However, how the presence of notch affects its mechanical properties remains unexplored. Here, we perform molecular dynamics simulations on a superplastic Cu50Zr50 NG containing a pre-existing notch under tensile loading, with focus on the notch sensitivity. Our results show that when the notch size is smaller than or comparable to the average grain size (d), the NG still exhibits a superplastic deformation and shows notch-insensitivity. When the notch size is larger than d, however, the NG fails by localized shear banding emanating from the notch root and shows notch-sensitivity. The origin of this transition arises from the competition between the shear band nucleation induced by the stress concentration at the notch root and the growth of shear transformation zones distributed in the glass-glass interfaces. Our results provide useful guidelines for the design and engineering of NG with notch for structural applications. [ABSTRACT FROM AUTHOR]