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The fundamental understanding of the effects of rare earth (RE) on the phase transformation of Fe-based alloys is essential in the development of advanced RE-containing high strength steels. In this work, we investigated the effects of La and Ce on the martensitic phase transformation of Fe in terms of the driving force and minimum energy path (MEP) using the first-principles calculations. The calculations of formation energy show that the RE substitution increases the stabilization of fcc-Fe and decreases that of bcc-Fe, thus decrease the driving force of phase transformation. Meanwhile, the analysis based on the generalized solid-state nudged elastic band (G-SSNEB) method indicates that in the RE-containing systems, an additional energy barrier appears when the phase transformation proceeds along the Bain transition path to c/a ratio of 1.14 in the FM state, which is associated with a sudden decrease in magnetization due to the hybridization between the orbitals of the RE atoms and those of the nearest neighbor Fe atoms. The results of potential-energy surfaces (PES) confirm that magnetic ordering and lattice volume change simultaneously with the Bain transition, and in comparison with pure Fe, the variation between the onset and the end structural volumes of the phase transformation is slight for the RE-containing Fe systems.

Evaluating the IgG titers targeting the S protein of SARS-CoV-2 by ELISA assays have been used in the development of several anti-SARS-CoV-2 vaccines in China. It is unclear whether the IgG levels against S protein tested by ELISA can monitor immune evasion against different Omicron variants. In the study, 88 recipients immunized with three doses of a COVID-19-inactivated vaccine were enrolled, whose serum samples were collected within 2 months after the third immunization. The IgG antibody levels were detected by using three commercial ELISA kits, which coated the S protein of the prototype, Omicron BA.1 and BA.5 variants respectively. The neutralizing activities of sera against the pseudotyped Omicron variant, prototype was determined. We also analyzed the correlation between the IgG titers with the neutralizing antibodies. The results showed that, after the third dose of the homologous inactivated vaccine, the neutralizing activity against the Omicron variant BA.1(GMT, 60) and BA. 5(GMT, 42) were decreased significantly compared with the prototype (GMT, 331) respectively ( P

Application of nitrogen (N) can increase the supply of N in soil and, in turn, can lead to higher yield-but also to large increase in emissions of greenhouse gases (GHGs) if applied in excess. To determine the optimum dose of N for maize planting system, we analysed the relationship between yield and emissions of GHGs at seven levels of N, namely 50, 100, 150, 200, 250, 300, and 350 kg ha

Rain-fed agriculture is an important part of the global agriculture system and plays a vital role in ensuring food security. Conservation tillage (CT) is widely used in USA maize cultivation in the Mid-west Corn Belt. Meanwhile, Chinese farmers' adoption of CT is limited and plastic film mulching (PM) is widely developed to increase maize yield in northern China. This paper compared the yield and nitrogen use efficiency (NUE) between CT and PM, and analyzed the reasons for the differences in the choice of maize cultivation practice. We collected 767 observations for CT and 217 observations for PM and analyzed how these two tillage practices affected yield. For NUE, there were 66 and 56 observations, respectively. The meta-analysis showed that PM significantly increased maize yield by 36% and NUE by 34% compared with the control, and CT significantly decreased maize yield by 5% and NUE by 15%. The effects of PM on maize yield were mainly determined by growing season precipitation (GSP) and temperature (GST). The yield response ratio was also influenced by the type of plastic film, mulching cycle, pH, soil saturated hydraulic conductivity, and soil bulk density. The negative effects of CT on yield could be alleviated under good hydrothermal conditions and with straw mulching. The yield response ratio was also affected by soil texture and N application rate. In conclusion, PM should be applied under limited hydrothermal conditions (GSP650 mm or GST23 °C), and CT was conducive to higher maize yield under good hydrothermal conditions (GSP650 mm or GST23 °C) . Besides, the average farm size was positively correlated with the CT total areas.

The increasing worldwide demand for traditional herbs has been met by growing cultivated herbs. It is undoubtedly very important to seek a reasonable cultivation mode for the yield, quality and long-term production stability of traditional herbs. In this study, licorice (Glycyrrhiza uralensis Fisch.) was investigated using a field experiment and a process-based model (Denitrification-Decomposition (DNDC) model) to study the effects of mulching methods on root yield and soil organic carbon (SOC) long-term changes. The field experiment contained four treatments: plat planting without mulching (CK), ridge-furrow maize straw mulching (SM), ridge-furrow plastic film mulching (RP), and plat planting with plastic film mulching (FP). Licorice root yield was significantly higher in the SM, RP, and FP than in the CK. SM, RP and FP treatments increased the accumulation of liquiritin and glycyrrhizin in licorice roots. The SM significantly increased SOC content, SOC stocks, SOC sequestration rate, dissolved organic carbon (DOC) content and microbial biomass carbon (MBC) compared to CK, but there was no significant difference in SOC and DOC among CK, RP and FP. The DNDC model was calibrated based on the field test data and showed that under the four CMIP6 SSPs scenarios, the predicted root yield of each treatment was increasing obviously. The production and stability of RP and FP were greater than CK and SM. The SOC under SM showed an increasing trend, whereas it continuously decreased under CK, RP, and FP in the future. The SOC of simulated RS treatment of straw incorporation plus a plastic film mulch was always at the highest value in all the treatments, and its root yield was slightly lower than that of RP and FP, the latter both were very close. Therefore, it is suggested that RS should be adopted to achieve sustained high yield while maintaining a high SOC level.