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The singularity at the crack tip can be smoothed by the non-local theory based on different types of weighted functions. In the paper, the characteristics of different types of the weighted functions and their effects on non-local model are analyzed. The effects of the stress intensity factor KI and KII on the all components of stress-strain field in the neighborhood of the crack tip are analyzed by different types of the weighted functions. It is shown that the larger intrinsic characteristic length scale is, the more significant the reduction of non-local strain with respect to the local strain predicted conventionally will be. The size of non-local strain field with the bell-shaped weighted functions is larger than that obtained by either Green's or Gaussian weighted functions. The non-local normal stress-strain components depends on the stress intensity factor KI and KII, the circumferential stress is related to the stress intensity factor KI. The effect of stress intensity factor KI on non-local radial stress is positive while the effect of KII is negative. The non-local circumferential stress is related only to the stress intensity factor KII while the non-local shear stress is related only to the stress intensity factor KI. The larger the intrinsic characteristic scale is, the more significant the reduction of non-local strain with respect to the local strain predicted conventionally will be.

As the depletion of traditional fossil fuels and environmental pollution become serious problems for human society, researchers are actively looking for renewable energy sources. Since hydrogen energy is considered a clean, efficient, and renewable alternative energy source, it is regarded as the most promising option. In this context, how to store hydrogen safely and efficiently has become the major challenge that hinders the actual application. To fill this gap, this paper proposes to utilize surfactant-modified graphene for hydrogen storage. Through a modified Hummers’ method and ultrasonic stripping, this study proposes to prepare graphene from graphite oxide with NaBH4. The surfactant sodium dodecyl benzene sulfonate (SDBS) was used as a dispersant during the reduction process to produce dispersion-stabilized graphene suspensions. Then, to investigate the characteristics of the graphene suspensions, X-ray diffraction (XRD), SEM, TEM, Fourier transform infrared (FT-IR), Raman, XPS, TG, and N2 adsorption⁻desorption tests were conducted. Finally, analytical models for hydrogen adsorption were investigated with Langmuir and Freundlich fittings. The results show that the application of SDBS can effectively reduce the agglomeration among graphene monolayers and increase the specific surface area of graphene, and that the adsorption behavior is consistent with the Freundlich adsorption model, and is a physical process.

Among recent advances in electronic packaging technologies, electrically conductive adhesives (ECAs) attract most researchers’ attention, as they are environment-friendly and simple to apply. ECAs also have a lower operating temperature and volume resistivity compared with conventional electronic conductive adhesives. In ECAs, the conducting fillers play a significant role in improving conductivity and strength. In this work, as filler additives, the silver nanowires/graphene nanocomposites (AgNWs-GNs) were successfully fabricated via a facile self-assembly method. The characteristics of the as-prepared nanocomposites were evaluated by FTIR (Fourier Transform infrared spectroscopy), XRD (X-ray Diffraction), XPS (X-ray photoelectron spectroscopy), TEM (Transmission electron microscope) and Raman tests, demonstrating a successful synthesis process. Different amounts of AgNWs-GNs were used as additives in micron flake silver filler, and the effects of AgNWs-GNs on the properties of ECAs were studied. The results suggested that the as-synthesized composites can significantly improve the electrical conductivity and shear strength of ECAs. With 0.8% AgNWs/GNs (AgNWs to GO (Graphite oxide) mass ratio is 4:1), the ECAs have the lowest volume resistivity of 9.31 × 10−5 Ω·cm (95.4% lower than the blank sample without fillers), while with 0.6% AgNWs/GNs (AgNWs to GO mass ratio is 6:1), the ECAs reach the highest shear strength of 14.3 MPa (68.2% higher than the blank sample).

Understanding the effect of a porous TiO2 nanolayer on the optical scattering and absorption through electrospun fibers is of great importance for the design and development of advanced optical extinction materials. Based on electrospinning and controllable self-assembly techniques, pure electrospun poly(vinylidene fluoride) (PVDF) fibers and TiO2-coated ones with different self-assembly cycles were prepared. The effect of TiO2 self-assembly cycles on surface parameters, e.g., thickness, assembled content, and porosity of the TiO2 nanolayer were determined by scanning electron microscopy, thermogravimetric analysis, and Fourier transform infrared spectroscopy. With an increase in the self-assembly cycles, the TiO2-coated electrospun PVDF fibers presented rougher surfaces and greater average diameters. According to the characterized surface parameters, the effects of the controllable self-assembly on the optical refractive index, absorption index, and infrared extinction were investigated to increase the optical properties of electrospun PVDF fibers. The results indicated that an increase of almost 120–130 cm−1 in infrared extinction could be achieved through the controllable self-assembly with only 5.7 wt. % assembled TiO2 content. This is highly efficient when compared with other coating modes. We believe that this study could give some positive guidance in the design of TiO2-coated electrospun fibers for improving their surface and optical properties.

Understanding the changes of soil respiration under increasing N fertilizer in cropland ecosystems is crucial to accurately predicting global warming. This study explored seasonal variations of soil respiration and its controlling biochemical properties under a gradient of Nitrogen addition during two consecutive winter wheat growing seasons (2013-2015). N was applied at four different levels: 0, 120, 180 and 240 kg N ha(-1) year(-1) (denoted as N0, N12, N18 and N24, respectively). Soil respiration exhibited significant seasonal variation and was significantly affected by soil temperature with Q10 ranging from 2.04 to 2.46 and from 1.49 to 1.53 during 2013-2014 and 2014-2015 winter wheat growing season, respectively. Soil moisture had no significant effect on soil respiration during 2013-2014 winter wheat growing season but showed a significant and negative correlation with soil respiration during 2014-2015 winter wheat growing season. Soil respiration under N24 treatment was significantly higher than N0 treatment. Averaged over the two growing seasons, N12, N18 and N24 significantly increased soil respiration by 13.4, 16.4 and 25.4% compared with N0, respectively. N addition also significantly increased easily extractable glomalin-related soil protein (EEG), soil organic carbon (SOC), total N, ammonium N and nitrate N contents. In addition, soil respiration was significantly and positively correlated with β-glucosidase activity, EEG, SOC, total N, ammonium N and nitrate N contents. The results indicated that high N fertilization improved soil chemical properties, but significantly increased soil respiration.

Fusarium verticillioides (teleomorph, Gibberella moniliformis) is an important plant pathogen that causes seedling blight, stalk rot, and ear rot in maize (Zea mays). During infection, F. verticillioides produce fumonsins B1 (FB1) that pose a serious threat to human and animal health. Recent studies showed that Set1, a methyltransferase of H3K4, was responsible for toxin biosynthesis in filamentous fungi. However, to date, the regulation of FvSet1 on FB1 biosynthesis remains unclear. In the current study, we identified only one Set1 ortholog in F. verticillioides (FvSet1) and found that the deletion of FvSET1 led to various defects in fungal growth and pathogenicity. More interestingly, the FvSET1 deletion mutant (ΔFvSet1) showed a significant defect in FB1 biosynthesis and lower expression levels of FUM genes. FvSet1 was also found to play an important role in the responses of F. verticillioides to multiple environmental stresses via regulating the phosphorylation of FvMgv1 and FvHog1. Taken together, these results indicate that FvSet1 plays essential roles in the regulation of FB1 biosynthesis, fungal growth and virulence, as well as various stress responses in F. verticillioides.