Search

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.

With the continuous development and maturity of the fifth-generation mobile network (5G) technology, the demand for multimedia service access is increasing, which poses huge challenges to the connectivity, caching capabilities, and computing capabilities of the Internet of Things (IoT) devices. Therefore, edge computing, as the key to achieving efficient edge data preprocessing and improving data access and response, is considered to be a hot technology for the next generation of mobile networks and future development. However, the current imbalance of computing resources on the edge, the lack of collaboration between nodes, and the lack of adaptability of optimization methods in a dynamic environment pose challenges to the development of edge computing. To strengthen the collaboration of nodes in the edge environment, we designed a collaborative task offloading and resource scheduling framework, including macro base station collaborative space ( $$\xi $$ BSCS) and micro base station collaborative space ( $$\mu $$ BSCS) to balance computing and caching resources in heterogeneous wireless networks. In addition, we formulate the collaborative computing offloading problem as a Markov Decision Process (MDP), and deep reinforcement learning (DRL) agents are deployed to make task offloading and resource allocation decisions. The DRL agent is deployed in each base station (BS) in a decentralized manner, observing the available computing and caching resources on the edge side, and designing an optimal resource allocation strategy for task offloading to maximize the benefits of the long-term system. The data-driven simulation results verify that the proposed scheme is effective in reducing the overall consumption of the system, maximizing the long-term benefits of edge resource allocation, and improving the success rate of task completion.

With the rapid socio-economic development in China, poverty alleviation and the reduction of the environmental footprint in the plastic film mulching (PM) planting system have become key to sustainable agricultural production. Although many studies have evaluated the maize yield, agricultural economic benefits, and greenhouse gas (GHG) emissions associated with PM through small-scale field experiments, identifying suitable PM regions in combination with their demographic characteristics and the future development of such systems has received little attention. This study combines a Denitrification-Decomposition (DNDC) model and demographic characteristics to determine the optimum PM region in rainfed areas of the Loess Plateau in northwest China. The results demonstrated that PM produced a higher maize yield, agricultural net profit (ANP), and cost-benefit ratio compared to a control treatment (CK) without PM. An agricultural income far above the poverty level would assist in meeting the goals of alleviating poverty and building a prosperous society. In addition, the PM system produced more GHG emissions, but had a lower greenhouse gas intensity (GHGI) than CK under both low (200 kg N ha−1) and high (300 kg N ha−1) nitrogen (N) fertilizer rates. This study developed a framework to evaluate maize yield alongside economic and environmental indicators. We concluded that PM should be adopted in areas with precipitation less than 500 mm, and concentrated in the region with rainfall of 200–400 mm. The results provide a theoretical basis for the sustainable development of the PM maize planting system, and will contribute to the desired goal of environmentally sustainable agricultural production.

High order phenomena in the visible range and with polarization dependence in the ultraviolet (UV) region of the microphotoluminescence (micro-PL) spectrum in whispering-gallery mode (WGM) ZnO microrod cavity have been thoroughly studied at room temperature. WGM ZnO microrod cavity with good crystallinity is produced by the CVD growth method, and the ZnO microrod structures are characterized by structural and optical methods. Through the micro-PL spectrum measurement of the ZnO microrod, it is found that high-order resonance peaks appeared in the visible region. The different polarization conditions can be adjusted by rotating the angles of the polarizer, and it is proved that the micro-PL spectrum has strong polarization-dependent behavior in the UV region. Our results imply broad application potentials in the study of ZnO microrod-based photonic cavity devices.

The electronic structure and spin polarization properties of monolayer GaP3 induced by transition metal (TM) doping were investigated through a first-principles calculation based on density functional theory. The calculation results show that all the doped systems perform spin polarization properties, and the Fe–doped system shows the greatest spin polarization property with the biggest magnetic moment. Based on the analysis from the projected density of states, it was found that the new spin electronic states originated from the p–d orbital couplings between TM atoms and GaP3 lead to spin polarization. The spin polarization results were verified by calculating the spin density distributions and the charge transfer. It is effective to introduce the spin polarization in monolayer GaP3 by doping TM atoms, and our work provides theoretical calculation supports for the applications of triphosphide in spintronics.

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.

Three phosphate transporter (PHT) genes of Gracilariopsis lemaneiformis were cloned, and the expression patterns under different phosphate concentrations were analyzed. The phylogenetic analysis indicated that the amino acid sequence of GlPHT2 shared high identity with high-affinity PHT in many species. Meanwhile, GlPHT1 and GlPHT3 showed significant similarity to the low-affinity PHT sequences of other species. The results of expression patterns analysis showed that glpht2 was significantly upregulated when glpht1 remained expression stable under low-phosphorus treatment. The expression of glpht3 is positively correlated with the concentration of environmental phosphorus. Therefore, these results provided important evidence of the mechanism of Pi uptake and use in G. lemaneiformis. In addition, the low-phosphorus fast-growing mutant WLP-22 showed traits superiority in both growth and photosynthetic activity.

The design of rare earth (RE) bearing steels requires a thorough understanding of the formation tendency of RE involved phases in steels, while searching for binary and ternary compounds with a wide variety of composition and permutation need a remarkable amount of experimentation which is nearly infeasible. In the present work, we perform a thorough search for the RE-contained compounds in steels by a data-driven high-throughput computational approach. The search results indicate that RE may react with O and N to form a large amounts of oxide and nitride inclusions, while only Y participate in the formation of sulfide inclusion Y2MnS4 and Y2CaS4. For the case of ternary compounds in Fe-based solid solution, it is found that RE prefers to form ternary phases with the non-metallic elements, i.e., B, C, O, P and Si, and only Y is found to combine with metal Cr to form YCr4Fe8. Finally, our screen suggests that RE can participate in the formation of the nano-scale precipitates of κ-carbides, L12 precipitates and B2 precipitates, but MC and M2C carbides.

Key distribution patterns (KDPs) are finite incidence structures satisfying a certain property which makes them widely used in minimizing the key storage and ensuring the security of communication between users in a large network. We construct a new KDP using t-design and combine two ω-KDPs to give new (ω-1)-KDPs, which provide secure communication in a large network and minimize the amount of key storage.

The reuse of high-cost single-use medical devices (SUD) is permitted in many countries, such as the United States, Germany and the United Kingdom, but strict regulatory requirements must be met. In addition to regulatory policies and regulations, such as market access mode and special requirements on Good Manufacture Practice (GMP), there are strict technical requirements on the potential risk control and quality assurance system. Therefore, effective risk assessment and risk control technology are the keys to ensure effective quality control and safe use of SUDs. In this article, based on analyzing the technological requirements of the national regulatory on SUDs in the United States, Germany and Britain, and combined with the review from latest relevant literature, to discuss the strategies of how to carry out scientific risk assessment. Some risk control technologies on the reuse of SUDs are introduced, which will provide support for the further study on risk control strategies and regulatory decisions for the reuse of SUDs in China.

Flow cytometry (FCM) technique has been widely applied to estimating the genome size of various higher plants. However, there is few report about its application in algae. In this study, an optimized procedure of FCM was exploited to estimate the genome size of two eukaryotic algae. For analyzing Alexandrium catenella, an important red tide species, the whole cell instead of isolated nucleus was studied, and chicken erythrocytes were used as an internal reference. The genome size of A. catenella was estimated to be 56.48 ± 4.14 Gb (1C), approximately nineteen times larger than that of human genome. For analyzing Gracilariopsis lemaneiformis, an important economical red alga, the purified nucleus was employed, and Arabidopsis thaliana and Chondrus crispus were used as internal references, respectively. The genome size of Gp. lemaneiformis was 97.35 ± 2.58 Mb (1C) and 112.73 ± 14.00 Mb (1C), respectively, depending on the different internal references. The results of this research will promote the related studies on the genomics and evolution of these two species.

In this study, the development of Gracilariopsis lemaneiformis tetrasporophytes during tetraspore formation and release was investigated with the aim to understand the physiological and biochemical bases during tetraspore formation and release especially from energy metabolism, contributing to elucidation of the control of fertility, and to discover indicators related to the fertility level. The accompanied changes in photosystem II (PSII) photosynthetic abilities, adenosine-5′-triphosphate (ATP) content, ribulose-1,5-bisphosphate carboxylase (Rubisco), and phosphoenolpyruvate carboxylase (PEPC) activities of three strains of G. lemaneiformis, the wild type, cultivar 981, and ZC, cultivated in the laboratory and collected from the field were measured. Light microscopy observations showed that the differentiation process for all tetrasporophytes could be divided into four phases. Cultivar 981 produced the least number of tetrasporangia and tetraspores, which confirmed the low fertility of this strain. The photosynthetic activity, measured by effective PSII quantum yield (Y(II)) showed, fell earlier and rose later, and the values in phase IV were the highest for all three strains during the development of tetrasporophytes. ATP content decreased as developmental process progressed, suggesting that the thalli utilized more substrate and energy in order to heal wounds caused by spore release in phases III and IV. Moreover, the variations in Rubisco activity had the similar trend as ATP content and the same pattern as the Y(II) values during tetrasporic development. PEPC activities were approximately 1 to 2 orders of magnitude higher than those of Rubisco during the development process in the laboratory and field samples, which suggested that an anaplerotic reaction of G. lemaneiformis is substantial because of high growth rates in phase I and high demand for organic and amino acids for the synthesis of major cell components such as proteins in phases II, III, and IV. The results also suggested that the fertility of G. lemaneiformis tetrasporophytes, coupled with the variation in photosynthetic and carboxylase activities, and its increased energy use would be useful characteristics when attempting to breed new strains of G. lemaneiformis.

There is potential for bicarbonate to improve crop yields and economic efficiency of marine algae. However, few studies have focused on the effect of bicarbonate on the growth, photosynthesis, and enzyme activity associated with carbon utilization, especially in commercial macroalgae. Here, the addition of bicarbonate (up to 420 mg L(-1)) to macroalgal cultures has been evaluated for Gracilariopsis lemaneiformis, Gracilaria vermiculophylla, and Gracilaria chouae with respect to growth rate, photosynthetic activity, carbonic anhydrase activity, and biochemical composition. The results showed that the effects of NaHCO3 on growth, chlorophyll a, phycoerythrin, photosynthetic oxygen evolution, photochemical parameters of PSI and PSII, carbonic anhydrase activity, and nitrogen content were significant (P 0.05) and followed the same pattern in the three species. The parameter values were promoted in lower NaHCO3 concentrations (up to 252 or 336 mg L(-1)) and inhibited in higher NaHCO3 concentrations (336 mg L(-1) for Gp. lemaneiformis and 420 mg L(-1) for the other two species). Moreover, species-specific differences induced by supplementation with bicarbonate were discovered during culture. Optimal concentrations of NaHCO3 used in this study were 252 mg L(-1) for Gp. lemaneiformis and 336 mg L(-1) for G. vermiculophylla and G. chouae. These results suggest that an adequate supplementation of sodium bicarbonate is a viable strategy for promoting growth and photosynthetic activity in some macroalgae as well as for improving biochemical composition. The study will help to accelerate the growth rate of algae and improve the quality of thalli, and will also be useful for enhancing the understanding of carbon utilization in macroalgae.

Some single-use medical devices are reprocessed and reused in some countries in the world, but the regulatory approach is different, and in some countries it isn't regulated yet. In this article, the regulatory status quo of single-use medical devices is reviewed. The regulatory development, important regulatory documents and regulatory approaches of single-use medical device reprocessing in the United States, Germany and the UK are introduced. And how to perform scientific risk assessment and effective risk control is discussed. The information is useful to establish China-specific regulations, and to develop relevant standards, guidelines or specifications and the risk control strategies.

Entrepreneurship research has been emerging endlessly for several decades, but little about its past study review. In this article, the author points out the current Chinese venture research situation through analysising and evaluating the entrepreneurship research scholars, academic journals, academic institutions and works by CSSCI.

According to the monetary policy operation of the People's Bank of China from 2007 January to 2010 June, the paper decomposed the monetary policy shock as anticipated and unanticipated components. By using Shanghai Futures Exchange (SHFE)'s daily trading data, variables such as short-term real interest rates and expected inflation are structured under 0 to 3 month, 3 to 6 month, 6 to 9 month and 9 to 12 month interval. The direction and degree of the impaction of monetary policy shock on the real interest rate and expected inflation was estimated by CEV analysis. The results showed that the real interest rate and monetary policies had negative correlation, but inflation and monetary policies are positive relative, especially 6 to 9 month and 9 to 12 month interval.