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With the climate change processes over times, all professions and trades in Three Gorges Reservoir Area will be influenced. One of the biggest challenges is the risk of rising sea level. In this situation, a large number of uncertainties for climate changes will be faced in Three Gorges Reservoir Area. Therefore, it is of importance to investigate the complexity of decision making on investing in the long term rising sea level risk related projects in Three Gorges Reservoir Area. This paper investigates the sea level and the temperature as the underlying assets in Three Gorges Reservoir Area. A real option model is constructed to evaluate potential sea level rising risk. We formulate European and American real option models into a linear parabolic variational inequalities and propose a power penalty approach to solve it. Then we obtain a nonlinear parabolic equation. It shows that the nonlinear parabolic equation is unique and solvable. Also, the solutions of the nonlinear parabolic equation converge to the solutions of the parabolic variational inequalities at the rate of order O(λ −k/2). Since the analytic solution of nonlinear parabolic equation is difficult to obtain, a fitted finite volume method is developed to solve it in case of European and American options, and the convergence of the nonlinear parabolic equation is obtained. An empirical analysis is presented to illustrate our theoretical results.

Agricultural disease image recognition has an important role to play in the field of intelligent agriculture. Some advanced machine learning methods associated with the development of artificial intelligence technology in recent years, such as deep learning and transfer learning, have begun to be used for the recognition of agricultural diseases. However, the adoption of these methods continues to face a number of important challenges. This paper looks specifically at deep learning and transfer learning and discusses the recent progress in the use of these advanced technologies for agricultural disease image recognition. Analysis and comparison of these two methods reveals that current agricultural disease data resources make transfer learning the better option. The paper then examines the core issues that require further study for research in this domain to continue to progress, such as the construction of image datasets, the selection of big data auxiliary domains and the optimization of the transfer learning method. Creating image datasets obtained under actual cultivation conditions is found to be especially important for the development of practically viable agricultural disease image recognition systems.

Heterosis, the phenomenon in which hybrids outperform their parents, has been utilized in maize (Zea mays L.) for over 100 years. To provide a more complete understanding of heterosis, we collected a comprehensive transcriptome and translatome dataset on seedling leaves for B73, Mo17, and their F1 hybrid, which provided a dynamic landscape of transcriptomic and translatomic variation in maize. Although additivity accounted for a large proportion of variation at two omics-levels, an elevated nonadditive effect was observed in the translatome, especially in the translated subgenome maize1 genes, and the genes that switched from additivity in the transcriptome to nonadditivity in the translatome were significantly enriched in the subgenome maize1. Many genes with allele-specific expression and translation show dramatic regulatory switches between the transcriptome and translatome, and partial genes with allele-specific translation underlying regulatory mechanism also exhibited subgenome bias. Interestingly, we found the translated isoforms show different expression patterns compared with transcriptome and more genes changed their dominant isoforms during the genetic flow from parents to the hybrid at the translatome level. The translated genes with switched dominant isoforms significantly biased to the subgenome maize2 while genes with conserved dominant isoforms significantly enriched in subgenome maize1. Together, the dynamic changed patterns in translatome across hybrid and parental lines show translational fractionation of the maize subgenomes, which may be associated with heterosis in maize and provides a potential theoretical basis for breeding.

Many researchers analyze malware through static analysis and dynamic analysis technology, and combine it with excellent deep learning algorithm, which has achieved good results in malware classification. However, many researches only use the. ASM file generated by decompiler or. Bytes file represented by hexadecimal for feature extraction. This paper fully integrates the features of these two files, and uses word frequency and two deep learning algorithms to extract 184 opcode features and 16 probability features from ASM file and section file of Kaggle dataset respectively. Then, double byte feature coding method is used to fuse the features of the two files. Finally, convolution neural network is used to classify the fused samples. The experimental results show that the accuracy is 98.68% and the logarithm loss is 0.022.

Background: Licorice is widely used as a hepatoprotective herb for thousands of years in Traditional Chinese Medicine, and its main chemical constituent glycyrrhizin (GL) is used as a treatment for chronic hepatitis in Japan for over 20 years. 18β-Glycyrrhetinic acid (GA) is the main active metabolite of GL. Objective: Series of GA derivatives were designed and synthesized, and their anti-HCV activities were screened to investigate structure-activity relationship (SAR). Besides, their in-silico ADMET properties were analyzed to search for promising lead compound for further identification of anti-HCV terpenoid candidate. Methods: GA derivatives were synthesized via reactions of oxidation, oxime, rearrangement, esterification and acylation, etc. In vitro anti-HCV activity of derivatives was tested on the HCV cell culture (HCVcc) system. In-silico ADMET properties analysis were performed via “pkCSM” and “SwissADME” platforms. Results: Eighteen GA derivatives were synthesized and their structures were confirmed by MS and NMR spectrums. All compounds exhibited superior HCV inhibitory activity to that of GA. Compound 2 possessed the most potent anti-HCV activity with IC50 value of 0.79 μM, which is nearly 58 times potent than SA (a previously reported potent anti-HCV terpenoids) and >200 times than GA. SAR revealed the introduction of 3-oxo, short-chain (C1-C3) aliphatic alcohols or cyclic aliphatic amines is conducive to improving anti-HCV activity. In-silico ADMET prediction demonstrated most of the potent compounds possessed favorable ADMET properties. Conclusion: Structural modification of GA at 3-position and 30-position is an effective approach to searching for potent anti-HCV agents. Compound 2, with the most potent anti-HCV activity and favorable in-silico ADMET properties, is a promising lead compound for further identification of anti-HCV terpenoid candidate.

Water erosion can deteriorate cement-treated bricks. The goal of this study was to investigate the use of multiple biological surface treatments (BSTs) on cement-treated bricks to enhance their resistance to water erosion. Calcite crystals were precipitated on the surface of cement-treated sand bricks by the microbial-induced calcite precipitation (MICP) technique. Multiple BSTs with MICP were used to enhance the properties of the cement-treated bricks further. The experimental results showed that, after a single BST, the flexural strength of the cement-treated bricks increased from 500 kPa to 750 kPa and the compressive strength increased from 3000 kPa to 4000 kPa. Erosion and water absorption were reduced by 71.2% and 16.3%, respectively. Compared with cement-treated bricks without any BST, the cement-treated bricks with triple MICP BSTs showed increases of nearly 140% and 100% in peak flexural and compressive strength, respectively. In addition, the triple BSTs resulted in 32% less water absorption compared with cement-treated samples without any BST. The surface of cement-treated bricks with triple BSTs was found to resist accelerated erosion over a 60 min time period. Overall, the results showed that BST can strengthen the erosion resistance of cement-treated bricks.

Deep placement of nitrogen fertilizer is a key strategy for improving nitrogen use efficiency. A two-year field experiment was conducted during the early rice growing seasons (March–July) of 2016 and 2017. The experimental treatments comprised two rice cultivars: Wufengyou 615 (WFY 615) and Yuxiangyouzhan (YXYZ), and three N treatments: mechanical deep placement of all fertilizers as basal dose at 10 cm soil depth (one-time deep-placement fertilization, namely OTDP fertilization); manual surface broadcast (the common farmer practice) of 40% N fertilizer at one day before sowing (basal fertilizer) followed by broadcast application of 30% each at tillering and panicle initiation stages; and no fertilizer application at any growth stage as a control. One-time deep-placement fertilization increased grain yield of both rice cultivars by 11.8%–19.6%, total nitrogen accumulation by 10.3%–13.1%, nitrogen grain production efficiency by 29.7%–31.5%, nitrogen harvest index by 27.8%–30.0%, nitrogen agronomic efficiency by 71.3%–77.2%, and nitrogen recovery efficiency by 42.4%–56.7% for both rice cultivars, compared with the multiple-broadcast treatment. One-time deep-placement fertilization reduced CH4-induced global warming potential (GWP) by 20.7%–25.3%, N2O-induced GWP by 7.2%–12.3%, and total GWP by 14.7%–22.9% for both rice cultivars relative to the multiple-broadcast treatment. The activities of glutamine synthetase and nitrate reductase were increased at both panicle-initiation and heading stages in both rice cultivars following one-time deep-placement fertilization treatment. Larger leaf area index at heading stage and more favorable root morphological traits expressed as larger total root length, mean root diameter, and total root volume per hill were also observed. One-time deep-placement fertilization could be an effective strategy for increasing grain yield and nitrogen use efficiency and lowering greenhouse-gas emissions under mechanical direct-seeded cropping systems.

Metal phosphides have shown great potential for potassium-ion batteries because of their high theoretical specific capacity. Nevertheless, most of the metal phosphide anodes are plagued by rapid capacity decay (caused by the large volume changes during the discharge/charge process), which would restrict their further practical application. Herein, a chemically bonded CuP2/C composite was prepared by a facile high-energy ball milling method. A potassium bis(trifluoromethanesulfonyl)imide (KFSI)-based electrolyte was adopted instead of a conventional KPF6-based electrolyte for the CuP2/C composite anode. Benefiting from the synergistic effects of the formation of strong P–O–C chemical bonds and the KFSI-based electrolyte, the CuP2/C composite anode exhibited high reversible capacity (451.4 mAh g−1 at 50 mA g−1), excellent rate performance (123.5 mAh g−1 at 1000 mA g−1), and superior cycling stability (300 mAh g−1 after 100 cycles). This work paves the way for the development of high-performance CuP2 anode for potassium-ion batteries.

International audience; AbstractSoil phosphorus (P) availability often limits plant productivity. Classical theories suggest that total P content declines at the temporal scale of pedogenesis, and ecosystems develop toward the efficient use of scarce P during succession. However, the trajectory of ecosystem P within shorter time scales of succession remains unclear. We analyzed changes to P pools at the early (I), middle (II), and late (III) stages of growth of plantation forests (PFs) and the successional stages of natural forests (NFs) at 1969 sites in China. We found significantly lower P contents at later growth stages compared to earlier ones in the PF (p < .05), but higher contents at late successional stages than in earlier stages in the NF (p < .05). Our results indicate that increasing P demand of natural vegetation during succession, may raise, retain, and accumulate P from deeper soil layers. In contrast, ecosystem P in PF was depleted by the more rapidly increasing demand outpacing the development of a P-efficient system. We advocate for more studies to illuminate the mechanisms for determining the divergent changes, which would improve forest management and avoid the vast degradation of PF ecosystems suffering from the ongoing depletion of P.

Thermochemical two-step CO2 splitting is a potential approach that fixes the sustainable resource into transportable liquid fuels. However, the harsh CO2 splitting conditions, the limited oxygen release kinetics and capacity of metal oxides block further promoted the CO yield and solar-to-fuel energy efficiency. Here, we propose a different carbon cycle assisted by Ni/La2O3 via coupling methane decomposition with thermochemical CO2 splitting, replacing conventional metal oxides cycle. Superior performance was demonstrated with methane conversion reached around 94% with almost pure H2 generation. Encouragingly, CO2 conversion of 98% and CO yield of 6.9 mmol g−1 derived from CO2 were achieved, with peak CO evolution rate (402 mL min−1 g−1) of orders of magnitude higher than that in metal oxide process and outstanding thermodynamic solar-to-fuel energy efficiency (55.5% vs. 18.5%). This was relevant to the synergistic activation of La2O3 and Ni for CO2 in carbon cycle, thus improving CO2 splitting reaction with carbon species.

Landfill sites are regarded as prominent sources of bioaerosols for the surrounding atmosphere. The present study focused on the emission of airborne bacteria and fungi in four seasons of a sanitary landfill site. The main species found in bioaerosols were assayed using high-throughput sequencing. The SourceTracker method was utilized to identify the sources of the bioaerosols present at the boundary of the landfill site. Furthermore, the health consequences of the exposure to bioaerosols were evaluated based on the average daily dose rates. Results showed that the concentrations of airborne bacteria in the operation area (OPA) and the leakage treatment area (LTA) were in the range of (4684 ± 477)-(10883 ± 1395) CFU/m3 and (3179 ± 453)-(9051 ± 738) CFU/m3, respectively. The average emission levels of fungal aerosols were 4026 CFU/m3 for OPA and 1295 CFU/m3 for LTA. The landfill site received the maximum bioaerosol load during summer and the minimum during winter. Approximately 41.39%- 86.24% of the airborne bacteria had a particle size of 1.1 to 4.7 µm, whereas 48.27%- 66.45% of the airborne fungi had a particle size of more than 4.7 µm. Bacillus sp., Brevibacillus sp., and Paenibacillus sp. were abundant in the bacterial population, whereas Penicillium sp. and Aspergillus sp. dominated the fungal population. Bioaerosols released from the working area and treatment of leachate were the two main sources that emerged in the surrounding air of the landfill site boundary. The exposure risks during summer and autumn were higher than those in spring and winter.

There exists an increasing need for precision measurement & pointing control and extreme motion stability for current and future space systems, e.g., Ultra-Performance Spacecraft (UPS). Some notable technologies of realizing Ultra-Pointing (UP) ability have been developed particularly for Ultra-accuracy Ultra-stability Ultra-agility (3U) spacecraft over recent decades. Usually, Multilevel Compound Pointing Control Techniques (MCPCTs) are deployed in aerospace engineering, especially in astronomical observation satellites and Earth observation satellites. Modern controllers and/or algorithms, which are a key factor of MCPCTs for 3U spacecraft, especially the jitter phenomena that commonly exist in a UPS Pointing Control System (PCS), have also been effectively used in some UP spacecraft for a number of years. Micro-vibration suppression approaches, however, are often proposed to deal with low-level mechanical vibration or disturbance in the microgravity environment that is common for UPS. This latter approach potentially is one of the most practical UP techniques for 3U tasks. Some emerging advanced Disturbance-Free Payload (DFP) satellites that exploit the benefits of non-contact actuators have also been reported in the literature. This represents an interesting and highly promising approach for solving some challenging problems in the area. This paper serves as a state-of-the-art review of UP technologies and/or methods which have been developed, mainly over the last decade, specifically for or potentially could be used for 3U spacecraft pointing control. The problems discussed in this paper are of reference significance to UPS and millisecond optical sensors, which are involved in Gaofeng Project, deep space exploration, manned space flight, and gravitational wave detection.

A Reynolds-Averaged Navier Stokes (RANS)-information analytical method for predicting Rotor-Stator Interaction (RSI) broadband noise is established in this paper. First, the turbulence information is deduced from RANS simulation result. Then, the unsteady load on the stator blade is calculated using a strip theory approach based on LINearized SUBsonic unsteady flow in cascade (LINSUB) and 2-D equivalence method. In the end, the sound power of RSI broadband noise is calculated by coupling the unsteady load on the stator blade with acoustic analogy and annular duct mode. The broadband noise model part of the RANS-information analytical method is validated against the upstream sound power of an annular cascade experimental bench. Besides, the RANS-information analytical method is used in predicting RSI broadband noise of a single-stage axial fan acoustic experimental bench, the results illustrate that the RANS-information analytical method can accurately predict the RSI broadband noise in different fan working conditions. After simplification the Wave Leading Edge (WLE) stator blade, the effect of WLE stator blade on RSI broadband noise is studies. Although the simplification may bring some discrepancies, the results illustrate that the RANS-information analytical method has the capability for further studies on the broadband noise reduction with WLE stator blade.

Tin phosphide (Sn-P) based materials, comprising abundant elements on the earth, have attracted much attention as anodes for alkali-ion batteries. As one of the emerging families of tin phosphides, Sn4P3 is fast becoming a vital alternative anode for next-generation alkali-ion batteries mainly owing to its stable phase, appropriate operating potential, and high theoretical capacity. However, the fast capacity decay caused by the volume changes and Sn agglomeration greatly hinder its practical application. Thus, the tremendous effect has been made the address the above issues. Herein, we retrospect the development of Sn-P anode using Sn4P3 as an indicator and categorize the implemented methods to solve the problem of Sn4P3 in published work into four strategies, which are designing hierarchical/hollow nanostructures, constructing robust physical barriers of carbonaceous materials, doping or introducing heterophase interfaces, and modifying the solid-electrolyte interphase (SEI) layer. Besides, the application of the proposed strategies in other Sn-P based materials (e.g., SnP3 and SnP) in alkali-ion batteries were discussed. Finally, the remained challenges and perspectives for Sn-P based anodes of alkali-ion batteries were presented. This review systematically retrospect the progress of Sn-P materials, which not only will promote the development of Sn-P based anodes but also help to generate fresh insight into similar alloy-based materials.

Zero-dimensional carbon dots have emerged as important nanofillers for the separation membrane due to their small specific size and rich surface functional groups. This study proposed a strategy based on hydrophobic carbon dots (HCDs) to regulate water channels for an efficient forward osmosis (FO) membrane. Thin-film composite (TFC) membranes with superior FO performance are fabricated by introducing HCDs as the nanofiller in the polyacrylonitrile support layer. The introduction of HCDs promotes the formation of the support layer with coherent finger-like hierarchical channels and micro-convex structure and an integrated polyamide active layer. Compared to the original membrane, TFC-FO membrane with 10 wt% HCDs exhibits high water flux (15.47 L m−2 h−1) and low reverse salt flux (2.9 g m−2 h−1) using 1 mol/L NaCl as the draw solution. This improved FO performance is attributed to the lower structural parameters of HCDs-induced water channels and alleviated internal concentration polarization. Thus, this paper provides a feasible strategy to design the membrane structure and boost FO performance.

Molecular platinum fluorides PtFn , n=1-6, are prepared by two different routes, photo-initiated fluorine elimination from PtF6 embedded in solid noble-gas matrices, and the reaction of elemental fluorine with laser-ablated platinum atoms. IR spectra of the reaction products isolated in rare-gas matrices under cryogenic conditions provide, for the first time, experimental vibrational frequencies of molecular PtF3 , PtF4 and PtF5 . Photolysis of PtF6 enabled a highly efficient and almost quantitative formation of molecular PtF4 , whereas both PtF5 and PtF3 were formed simultaneously by subsequent UV irradiation of PtF4 . The vibrational spectra of these molecular platinum fluorides were assigned with the help of one- and two-component quasirelativistic DFT computation to account for scalar relativistic and spin-orbit coupling effects. Competing Jahn-Teller and spin-orbit coupling effects result in a magnetic bistability of PtF4 , for which a spin-triplet (3 B2g , D2h ) coexists with an electronic singlet state (1 A1g , D4h ) in solid neon matrices.

BACKGROUND: University laboratory is an important place to carry out scientific research and related teaching activities, but the environmental pollution caused by waste discharge cannot be ignored. OBJECTIVE: The research aims to explore the environmental pollution caused by the waste of chemical laboratory, and the direct or indirect harm to human health. METHODS: The main pollutants discharged by the laboratories are counted through the analysis of the waste treatment status of university chemical laboratory. Then, the harm of the discharged pollutants to the environment is analyzed by experiments to find out the main pollution problem of the chemical laboratory - wastewater pollution. The groundwater pollution caused by laboratory wastewater discharge is analyzed, and the human health risk caused by it is evaluated. RESULTS: The results show that the discharge of chemical laboratory waste in colleges and universities will cause harm to human health. The results of health risk assessment show that benzene, trichloromethane, and dichloromethane are the main pollutants, and the use of chemical reagents is one of the important reasons for the surge of laboratory waste in colleges and universities; in the carcinogenesis of multi pollutants, compared with skin absorption, the risk of cancer caused by drinking water absorption was higher, and the corresponding risk value is 5.56e-07. CONCLUSIONS: The discharge of university chemical laboratory waste will cause harm to human health. This exploration provides reference for the study of environmental pollution and health risk assessment caused by waste discharge of university chemical laboratory.

BACKGROUND: The quality and safety of drinking water directly affect the health of the local population. However, due to the limited conditions in poor rural areas, the safety of drinking water is more prominent. OBJECTIVE: It aimed to ensure the safety of drinking water quality and population health in poor rural areas. METHODS: A rural poor area was taken as an example, the drinking water plants were monitored during wet season and dry season, respectively, and the water quality indicators of rural drinking water in the city in 2019 were detected and analyzed. Finally, based on the non-carcinogenic risk and carcinogenic risk evaluation model proposed, the health risk assessment of chemical pollutants in drinking water was carried out. RESULTS: In 2019, the qualified rate of drinking water in rural areas of the city was generally low. The average annual carcinogenic risk of drinking water in poor rural areas of the city was 1.57×10–6 (a–1), and the average annual non-carcinogenic risk was 5.38×10–9 (a–1). CONCLUSION: The health risk assessment model proposed can well evaluate the health risks of drinking water. The research provides a scientific basis for the risk management of drinking water of relevant departments.

The simultaneous construction of two different chiralities via a simple operation poses considerable challenge. Herein a cationic gold-catalyzed asymmetric hydroarylation of ortho-alkynylaryl ferrocenes derivatives is developed, which enable the simultaneous construction of axial and planar chirality. The here identified TY-Phos derived gold complex is responsible for the high yield, good diastereoselectivity (>20:1 dr), high enantioselectivities (up to 99% ee) and mild conditions. The catalyst system also shows potential application in the synthesis of chiral biaryl compounds. The cause of high enantioselectivity of this hydroarylation is investigated with density functional theory caculation., The simultaneous construction of two different types of chiralities is challenging. Here, the authors report a cationic gold-catalyzed asymmetric hydroarylation of ortho-alkynylaryl ferrocene derivatives, which enabled the simultaneous construction of axial and planar chirality.

Reconstruction of sedimentary evolution plays a significant role in the investigation of natural groundwater contamination and stratigraphic mineral resources. In this paper, the variation in sedimentary characteristics and sedimentary evolution were studied by lithology, chronology and organic matter with the high-resolution grain size parameters of boreholes for Quaternary in northern Jianghan Basin. Following more traditional plotting of grain size parameters and summary statistics, visual categorization and analysis of grain size frequency distribution curves provided an effective measure for the identification of sedimentary facies. Combining with the Fisher model, new and highly efficient discriminant formulas were established, and tested for the validity. Additionally, the sedimentary evolution process and the provenance of different sedimentary facies were identified with the help of organic matter and δ13Corg data, provided geological information to explore the natural contamination of reducing arsenic ions and excessive nitrate in strata. The identification results suggest that fluvial and lacustrine sediments are dominant in the area, and the regional sedimentary environment is uniform and not affected by the transgression. The analysis results of grain size with organic matter parameters are consistent for discriminating sedimentary facies, which verified the rationality of grain size analysis and confirmed the use of organic matter content to be effective in identifying the process of fluvial and lacustrine sediments. Based on the chronological results of Optically Stimulated Luminescence dating and sedimentary facies determination, the sedimentary evolutionary process was deduced during the Quaternary for the study area. This research has important significance for the division and correlation of Quaternary borehole strata, underground contamination study, as well as environmental planning and protection.

In nature and the technology world, acquired signals and time series are usually affected by multiple complicated factors and appear as multi-component non-stationary modes. In many situations it is necessary to separate these signals or time series to a finite number of mono-components to represent the intrinsic modes and underlying dynamics implicated in the source signals. Recently the synchrosqueezed transform (SST) was developed as an empirical mode decomposition (EMD)-like tool to enhance the time-frequency resolution and energy concentration of a multi-component non-stationary signal and provides more accurate component recovery. To recover individual components, the SST method consists of two steps. First the instantaneous frequency (IF) of a component is estimated from the SST plane. Secondly, after IF is recovered, the associated component is computed by a definite integral along the estimated IF curve on the SST plane. The reconstruction accuracy for a component depends heavily on the accuracy of the IFs estimation carried out in the first step. More recently, a direct method of the time-frequency approach, called signal separation operation (SSO), was introduced for multi-component signal separation. While both SST and SSO are mathematically rigorous on IF estimation, SSO avoids the second step of the two-step SST method in component recovery (mode retrieval). The SSO method is based on some variant of the short-time Fourier transform. In the present paper, we propose a direct method of signal separation based on the adaptive continuous wavelet-like transform (CWLT) by introducing two models of the adaptive CWLT-based approach for signal separation: the sinusoidal signal-based model and the linear chirp-based model, which are derived respectively from sinusoidal signal approximation and the linear chirp approximation at any time instant. A more accurate component recovery formula is derived from linear chirp local approximation. We present the theoretical analysis of our approach. For each model, we establish the error bounds for IF estimation and component recovery.

How the suitable distribution of a given grassland type will respond to policy implementation and climate change is a prerequisite and the basis for effective grassland management and sustainable development. The maximum entropy (MaxEnt) model as a comprehensive evaluation method at species level was successfully used to simulate the temporal and spatial changes in the geographical distribution of Kobresia meadow in China’s Three-River Headwaters (TRH) region under the context of policy implementation and climate change. There were three main findings. First, there are the six dominant environmental variables affecting the distribution of Kobresia meadow (these being elevation, precipitation variation coefficient, March precipitation, April precipitation, April minimum temperatures, and May minimum temperatures: their threshold values are 3500–4000 m, 86–100, 8.5 mm, 12 mm, –3.5°C and 1.5°C, respectively, which indicate the most suitable conditions for Kobresia meadow distribution). Second, under current (2005–2014) climate conditions, the suitable distribution of Kobresia meadow gradually decreases from east to west, with the largest area in the east. Implementation of the ecological conservation policy in the TRH has greatly improved the ecological environment in lower elevation and high population areas. This has benefited the growth of Kobresia meadow and enlarged its suitable areas. Third, compared with the current distribution, areas suitable for Kobresia meadow will increase by 25.4–33.0% in the 2050s (2041–2060) and 17.4–33.0% in the 2070s (2061–2080) under four Representative Concentration Pathway (RCP) scenarios. More importantly, from the 2050s to the 2070s, areas suitable for Kobresia meadow will decrease or stabilise, bringing new challenges for protection and utilisation.

CdTe solar cell technology is one of the lowest-cost methods of generating electricity in the solar industry, benefiting from fast CdTe absorber deposition, CdCl2 treatment and Cu doping. However, Cu doping has low photovoltage and issues with instability. Doping group V elements into CdTe is therefore a promising route to address these challenges. Although high-temperature in situ group V doped CdSeTe devices have demonstrated efficiencies exceeding 20%, they face obstacles including post-deposition doping activation processes, short carrier lifetimes and low activation ratios. Here, we demonstrate low-temperature and effective ex situ group V doping for CdSeTe solar cells using group V chlorides. For AsCl3 doped CdSeTe solar cells, the dopant activation ratio can be 5.88%, hole densities reach >2 × 1015 cm−3 and carrier lifetime is longer than 20 ns. Thus, ex situ As doped CdSeTe solar cells show open-circuit voltages ~863 mV, compared to the highest open-circuit voltage of 852 mV for Cu doped CdSeTe solar cells. Doping CdTe solar cells with group V elements could overcome the limitations in voltage output and device stability of copper doping, yet implementation remains challenging. Now, Li et al. have devised an ex situ doping approach that is based on group V chloride solutions and low-temperature annealing.

Two new sesquiterpenoid lactone derivatives, linderin A (1) and linderin B (2) comprising a sesquiterpenoid lactone and a methyl geranylhomogentisate moiety together with six known compounds were isolated from the roots of Lindera aggregata. Their chemical structures were elucidated using extensive spectroscopic analysis including 1 D, 2 D NMR, and HR-ESI-MS data and compared with previously reported data. The absolute configurations of 1 and 2 were assigned based on the electronic circular dichroism calculation. Compound 2 showed moderate anticoagulant activity.

The large-scale application of ionic surfactants in industrial and agricultural production has caused great harm to the environment due to by-products. In order to remove this pollutant from the environment, graphene oxide as an adsorption material has received extensive attention. However, practically, it is difficult to separate the GO from aqueous solutions, making water treatment on a large scale challenging. To allow the recycling of GO, as well as enhance its adsorption ability to remove surfactants from water, a composite of magnetic graphene oxide (MGO) and 1-dodecyl-3-methylimidazolium chloride ionic liquid (IL) was synthesized. The MGO was prepared by coprecipitation, and IL-MGO was prepared by ultrasonic impregnation. Nitrogen adsorption-desorption curves show that the specific surface area of the composite was increased by the addition of the IL, from 103.28 to 163.35 m2/g. Finally, the adsorption ability of MGO and IL-MGO for the nonionic surfactant NP10EO was investigated. The results showed that the adsorption of MGO on NP10EO fits the Langmuir isothermal model and the quasi-second-order kinetic model. In addition, the equilibrium adsorption capacity of NP10EO by MGO at 298K, 308K, and 318K can reach 87.03 mg/g, 156.25 mg/g, and 214.13 mg/g. The adsorption is an endothermic reaction that occurs spontaneously and is governed by physical adsorption. The adsorption of IL-MGO on NP10EO conforms to the Langmuir isotherm model and the quasi-second-order kinetic model. At 298K, 308K, and 318K, the equilibrium adsorption capacity of NP10EO by MGO reached 261.02 mg/g, 280.24 mg/g, and 295.03 mg/g, respectively. Compared with the two results, the incorporation of IL greatly improved the adsorption capacity of MGO to NP10EO.

In this paper, both nanocrystalline alloy (Fe73.5Cu1Nb3Si15.5B7) ribbon samples and toroidal samples (wound ribbon) are annealed at different temperatures in order to consider the influence of inner stress on the magnetization properties. Then the AC magnetization properties of these samples are measured. Combined with the measured results, the influence of inner stress on nanocrystalline alloy’s microstructure is analyzed quantitatively based on the loss separation principle and the statistical theory of loss. By comparing measured macroscopic magnetization characteristics and excess loss, the equivalent stress state of the toroidal sample is evaluated. Furthermore, two kinds of samples’ excess loss under different annealing temperatures are analyzed, and the effectiveness of stress relief at optimal annealing temperature is validated.

The pathogen cereal cyst nematode (CCN) is deleterious to Triticeae crops and is a threat to the global crop yield. Accession no. 1 of Aegilops variabilis, a relative of Triticum aestivum (bread wheat), is highly resistant to CCN. Our previous study demonstrated that the expression of the phenylalanine ammonia lyase (PAL) gene AevPAL1 in Ae. variabilis is strongly induced by CCN. PAL, the first enzyme of phenylpropanoid metabolism, is involved in abiotic and biotic stress responses. However, its role in plant-CCN interaction remains unknown. In the present study, we proved that AevPAL1 helps to confer CCN resistance through affecting the synthesis of salicylic acid (SA) and downstream secondary metabolites. The silencing of AevPAL1 increased the incidence of CCN infection in roots and decreased the accumulation of SA and phenylalanine (Phe)-derived specialized metabolites. The exogenous pre-application of SA also improved CCN resistance. Additionally, the functions of PAL in phenylpropanoid metabolism correlated with tryptophan decarboxylase (TDC) functioning in tryptophan metabolism pathways. The silencing of either AevPAL1 or AevTDC1 exhibited a concomitant reduction in the expression of both genes and the contents of metabolites downstream of PAL and TDC. These results suggested that AevPAL1, possibly in coordination with AevTDC1, positively contributes to CCN resistance by altering the downstream secondary metabolites and SA content in Ae. variabilis. Moreover, AevPAL1 overexpression significantly enhanced CCN resistance in bread wheat and did not exhibit significant negative effects on yield-related traits, suggesting that AevPAL1 is valuable for the genetic improvement of CCN resistance in bread wheat.

A visible-light-induced carbonylation of indoles with phenols for the synthesis of indole-3-carboxylates has been developed. The reaction proceeded via a radical carbonylation process in which elementary I2 was used as an effective photosensitive initiator and, thus, avoided the use of transition metal catalysts. A series of different aryl indole-3-carboxylates were prepared in moderate to good yields. The broad applicability of this methodology was further highlighted by the late-stage functionalization of several phenol-containing natural products and pharmaceuticals.

In this paper, a novel direction of arrival (DOA) estimation algorithm using directional antennas in cylindrical conformal arrays (CCAs) is proposed. To eliminate the shadow effect, we divide the CCAs into several subarrays to obtain the complete output vector. Considering the anisotropic radiation pattern of a CCA, which cannot be separated from the manifold matrix, an improved interpolation method is investigated to transform the directional subarray into omnidirectional virtual nested arrays without non-orthogonal perturbation on the noise vector. Then, the cross-correlation matrix (CCM) of the subarrays is used to generate the consecutive co-arrays without redundant elements and eliminate the noise vector. Finally, the full-rank equivalent covariance matrix is constructed using the output of co-arrays, and the unitary estimation of the signal parameters via rotational invariance techniques (ESPRIT) is performed on the equivalent covariance matrix to estimate the DOAs with low computational complexity. Numerical simulations verify the superior performance of the proposed algorithm, especially under a low signal-to-noise ratio (SNR) environment.

Background Drought threatens the food supply of the world population. Dissecting the dynamic responses of plants to drought will be beneficial for breeding drought-tolerant crops, as the genetic controls of these responses remain largely unknown. Results Here we develop a high-throughput multiple optical phenotyping system to noninvasively phenotype 368 maize genotypes with or without drought stress over a course of 98 days, and collected multiple optical images, including color camera scanning, hyperspectral imaging, and X-ray computed tomography images. We develop high-throughput analysis pipelines to extract image-based traits (i-traits). Of these i-traits, 10,080 were effective and heritable indicators of maize external and internal drought responses. An i-trait-based genome-wide association study reveals 4322 significant locus-trait associations, representing 1529 quantitative trait loci (QTLs) and 2318 candidate genes, many that co-localize with previously reported maize drought responsive QTLs. Expression QTL (eQTL) analysis uncovers many local and distant regulatory variants that control the expression of the candidate genes. We use genetic mutation analysis to validate two new genes, ZmcPGM2 and ZmFAB1A, which regulate i-traits and drought tolerance. Moreover, the value of the candidate genes as drought-tolerant genetic markers is revealed by genome selection analysis, and 15 i-traits are identified as potential markers for maize drought tolerance breeding. Conclusion Our study demonstrates that combining high-throughput multiple optical phenotyping and GWAS is a novel and effective approach to dissect the genetic architecture of complex traits and clone drought-tolerance associated genes.

Biodiesel has emerged as a non-toxic, biodegradable, and renewable fuel substitute that can be readily produced via the esterification reaction of free fatty acids. The present work explores the potential of 12-tungstophosphoric acid(TPA) anchored two-dimensional(2D) ITQ-2 zeolite(TPA/ITQ-2) as heterogeneous acid catalysts for biodiesel production. TPA/ITQ-2 material was prepared by swelling, delamination, and subsequent wetness incipient impregnation approach. The prepared catalysts were comprehensively characterized by powder X-ray diffraction, N2 adsorption/desorption, temperature-programmed desorption of ammonia, flourier transform infrared spectroscopy, and transmission electron microscopy. The catalytic activity of TPA/ITQ-2 for biodiesel production was evaluated by the esterification reaction of oleate acid with methanol. Process parameters, such as reactant molar ratio and TPA loading were optimized. Due to the superior mass transfer and adequate stable acid sites, 2D TPA/ITQ-2 showed a higher catalytic activity and a better recyclable stability than the 3D and layered TPA/zeolites. This work will provide new opportunities for the design of 2D zeolite-based acid catalysts for biodiesel production.

The 2019 Mw 6.1 Castillejos earthquake occurred in the Zambales range of the central Luzon Island in Philippines. No active fault was reported around the seismogenic zone according to previous investigations. This earthquake draws attention for assessment in seismic risk along the Marikina Valley fault system (MVFS) near the Manila dense metropolitan population. The Coulomb failure stress (CFS) change on the MVFS is estimated by the coseismic faulting model derived from the inversion of coseismic deformation field observed from the Differential Interferometric Synthetic Aperture Radar using both the Advanced Land Observing Satellite-2 and Sentinel-1 Synthetic Aperture Radar (SAR) images. The predicted CFS change is less than 0.5 kPa that implies insignificant Coulomb stress accumulation on the MVFS after the Mw 6.1 Castillejos event. However, the recorded 14 moderate and strong earthquakes in and around the Luzon islands caused significant CFS drop on the MVFS. This might delay the occurrence of the earthquake for 0.2–50 yr on the MVFS.

Portable ultrasound has been extensively used for diagnostic applications in health monitoring, emergency rooms, and ambulances. However, these handheld ultrasound systems may suffer from heat and battery issues attributed to the large power consumption of the transmitter. Additionally, the largest portion of the direct current (DC) power consumption can be attributed to the amplifier in the digital-to-analog converter (DAC) of the transmitter and to the analog-to-digital converter (ADC) of the receiver. Therefore, the number of transmit/receive channels in a portable ultrasound instrument is one of the crucial design factors regarding heat and battery related issues. To address these problems, we propose an acoustic-field beamforming (AFB) technique for low-power portable ultrasound systems with a single receive and five transmit channels. Finally, the simulation, experimental, and in vivo results verified the feasibility of this approach.

Most of the cathode materials for potassium ion batteries (PIBs) suffer from poor structural stability due to the large ionic radius of K + , resulting in poor cycling stability. Here we report a low-strain potassium-rich K 1.84 Ni[Fe(CN) 6 ] 0.88 ∙0.49H 2 O (KNiHCF) as a cathode material for PIBs. The as-prepared KNiHCF cathode can deliver reversible discharge capacity of 62.8 mAh g -1 at 100 mA·g -1 , with a high discharge voltage of 3.82 V. It can also achieve a superior rate performance of 45.8 mAh g -1 at 5000 mA g -1 , with a capacity retention of 88.6% after 100 cycles. The combination of in situ characterizations and theoretical calculations unveils that the superior performance of KNiHCF cathode results from low-strain de-/intercalation mechanism, intrinsic semiconductor property and low potassium diffusion energy barrier. In addition, the high power density and long term stability of KNiHCF//graphite full cell have further proved the feasibility of K-rich KNiHCF cathode in PIBs. This work is expected to provide meaningful guidance to develop Prussian blue analogues as cathode materials for high-performance PIBs.

A Co-catalyzed highly regio- and enantioselective reductive coupling of alkynes and aldehydes has been developed under visible light photoredox dual catalysis. A variety of enantioenriched allylic alcohols have been obtained by using unsymmetrical internal alkynes and commercially available catalyst, chiral ligand, and reagents. It is noteworthy that this approach has considerable advantages, such as excellent regio- (>95:5 for >40 examples), stereo- (up to >95:5 E/Z), and enantioselectivity (92-99% ee, >35 examples) control, mild reaction conditions, broad substrate scope, and good functional group compatibility, making it a great improvement to enantioselective alkyne-aldehyde reductive coupling reactions.

Classical strong metal–support interaction (SMSI) has attracted intensive attention in the heterogeneous catalysis field; however, its crystalline TiOx overlayer and reversible feature often curtai...

Carbon dots are a new class of carbon materials with ultrasmall size and unique physicochemical property. They have been widely studied since their discovery and have been gradually applied in various fields due to their quantum size, abundant surface functional groups, great biocompatibility, non-toxicity and photoluminescence characteristics. Recently, applications of carbon dots in the new generation batteries have also shown great potential. This review systematically summarized the research status of carbon dots in lithium-ion batteries (LIBs), sodium-ion batteries (SIBs), potassium ion batteries (PIBs), lithium-sulfur batteries (LSBs), etc., and discussed the applications of carbon dots in electrode materials, separator and electrolyte of advanced batteries in detail. Moreover, we also analyzed the challenges and development directions of carbon dots in batteries. This review aims to provide guidance and reference for the design and manufacture of the next generation of high-performance batteries.

In modern industrial processes, dynamics and nonlinearities are two main difficulties for soft sensing of key quality variables. Thus, nonlinear dynamic models like long short-term memory (LSTM) network have been applied for data sequence modeling due to its powerful representation ability. Nevertheless, most dynamic methods cannot deal with data series with irregular sampling intervals, which is a common phenomenon in many industrial plants. To handle this problem, a novel sampling-interval-aware LSTM (SIA-LSTM) is proposed in this paper, which takes the sampling intervals between sequential samples into consideration to adjust the influence of the previous sample on the current one. To this end, two non-increasing functions of the sampling interval are designed to weight different sampling intervals in the dynamic data sequence. Then, each sampling-interval weight is multiplied to the corresponding previous hidden state to adjust its impact. Finally, the adjusted hidden state is used as an adaptive input for the three control gates in each LSTM unit to obtain the current hidden state. The proposed SIA-LSTM is applied to an actual hydrocracking process for soft sensor of the C5 content in the light naphtha and the final boiling point of the heavy naphtha.

Numerous volatile organic compounds and odors are generated when municipal solid wastes decompose in landfill sites. Three biofilters (BF-1, BF-2, and BF-3) were deployed to remove H2S and NH3 accumulated under high density polyethylene films in a 30,000 m2 area landfill site in North China. Results showed that the inlet concentrations of H2S and NH3 were 16.4–220.3 mg/m3 and 2.0–56.4 mg/m3, respectively. Outlet concentrations were reduced to 1.0–33.1 mg/m3 for H2S and 0–9.2 mg/m3 for NH3. The H2S removal efficiencies were around 91.1 % for BF-1, 87.0 % for BF-2, and 82.6 % for BF-3 in a steady state. The respective removals of NH3 were 92.0 %, 89.3 %, and 81.1 %. Thus, H2S and NH3 were both treated effectively by the biofilters. The intake load presented a seasonal variation. A high elimination capacity was obtained in the biofilter harvesting high inlet load. High throughput sequencing technology was utilized to assay the microbial populations in the biofilters. Pseudomonas sp., Alicyclobacillus sp., Sphingomonas sp., and Rhodanobacter sp, which were linked to the degradation of H2S and NH3, were isolated and identified. Their characteristics and distributions in the biofilters depended on the inlet concentration of substrates and the microenvironment within the packing materials. The results from this bio-product analysis indicated that most of H2S was bio-oxidized into sulfur and sulfate while NH3 was converted into nitrate or dissolved into the liquid phase mainly by absorption or chemical neutralization in the biofilters.

Sepsis is a leading cause of mortality in intensive care unit worldwide, it's accompanied by immune cell dysfunction induced by multiple factors. However, little is known about the specific alterations in immune cells in the dynamic pathogenesis of sepsis secondary to bacterial pneumonia. Here, we used single cell RNA sequencing (scRNA-seq) to profile peripheral blood mononuclear cells (PBMCs) in a healthy control and two patients with sepsis secondary to bacterial pneumonia, including acute, stable and recovery stage. We analyzed the quantity and function of immune cells. During disease course, interferon gamma response was upregulated; T/NK cell subtypes presented activation and exhaustion properties, which might be driven by monocytes through IL-1β signaling pathways; The proportion of plasma cells was increased, which might be driven by NK cells through IFN signaling pathways; Additionally, interferon gamma response was upregulated to a greater degree in sepsis secondary to pneumonia induced by SARS-COV-2 compared with that induced by influenza virus and bacteria.

A novel good water-soluble macrocycle containing two pyridinium moieties was synthesized in high yield. It could form 1:1 complexes with neutral guests containing naphthalene or phenyl units in water. The water-soluble macrocycle can selectively encapsulate naphthalene to form a 1:1 complex over a variety of polycyclic aromatic hydrocarbons.

Single-atom catalysts (SACs) with complete dispersion of metal species on substrates provide the ultimate atom economy and opportunities for improved heterogenous catalysis or to develop more catal...

In this paper we consider four-superlinear Kirchhoff equations. In contrast to most studies, we allowed the potential V is indefinite, precisely, the operator −Δ+V possesses a finite-dimensional ne...

It is important to develop an efficient noble-metal-based catalyst that has a wide work temperature window and good stability for CO preferential oxidation in H2 (CO-PROX), a key step to purify ind...

The determination of trace phenols in food samples is of great significance, but it is still very challenging due to the low concentration and complex matrix. A robust method was developed to determine trace phenols in food sample by combining headspace-solid phase microextraction (HS-SPME) with gas chromatography-mass spectrometry (GC-MS). The hydroxylated ordered mesoporous polymer (OMP-OH) synthesized by solvent-free strategy possessed ordered mesoporous structure and high specific surface area and was used as SPME fiber coating. Factors affecting the extraction efficiency were optimized, including extraction time, extraction temperature, pH value, salt effect, and desorption conditions. Under the optimal conditions, OMP-OH coating exhibited a high capability for the enrichment of phenols, which was 2~8 times that of commercial SPME coating. Moreover, the coating can be reused for more than 150 times without a significant change in performance. Linear ranges of this method were 0.5~10000 ng L−1, of which 5~10000 ng L−1 for 2-nitrophenol and 1~10000 ng L−1 for 2, 4-dichlorophenol. The limits of detection (LODs) for phenols in tomato and grape are 0.19~2.13 ng L−1 and 0.21~2.41 ng L−1, respectively. High enrichment factors (439~1851), good precision (RSD< 8.87%), and superior reproducibility (RSD< 10.0%) were obtained. Ultimately, the established method was successfully applied to quantify the phenols in real food samples, i.e., tomato and grape. The results demonstrated that the established method was very promising for the determination of trace phenols in food samples with complex matrix.

A bacterial strain ASLT-13 was successfully isolated from activated sludge and identified as Pseudomonas amygdali. Gas chromatograph-mass spectrometer (GC-MS) analysis indicated that strain ASLT-13...

Purpose A novel proportional integral derivative-extended state disturbance observer-based control (PID-ESDOBC) algorithm is proposed to solve the nonlinear hydrodynamics, parameters perturbation and external disturbance in yaw control of remote operated vehicles (ROVs). The effectiveness of PID-ESDOBC is verified through the experiments and the results indicate that the proposed method can effectively track the desired attitude and attenuate the external disturbance. Design/methodology/approach This study fully investigates the hydrodynamic model of ROVs and proposes a control-oriented hydrodynamic state space model of ROVs in yaw direction. Based on this, this study designs the PID-ESDOBC controller, whose stability is also analyzed through Kharitonov theorem and Mikhailov criterion. The conventional proportional-integral-derivative (PID) and active disturbance rejection control (ADRC) are compared with our method in our experiment. Findings In this paper, the authors address the nonlinear hydrodynamics, parameters perturbation and external disturbance problems of ROVs with multi-vector propulsion by using PID-ESDOBC control scheme. The advantage is that the nonlinearities and external disturbance can be estimated accurately and attenuate promptly without requiring the precise model of ROVs. Compared to PID and ADRC, both in overshoot and settling time, the improvement is 2X on average compared to conventional PID and ADRC in the pool experiment. Research limitations/implications The delays occurred in the control process can be solved in the future work. Practical implications The attitude control is a kernel problem for ROVs. A precise kinematic and dynamic model for ROVs and an advanced control system are the key factors to obtain the better maneuverability in attitude control. The PID-ESDOBC method proposed in this paper can effectively attenuate nonlinearities and external disturbance, which leads to a quick response and good tracking performance to baseline controller. Social implications The PID-ESDOBC algorithm proposed in this paper can be ensure the precise and fast maneuverability in attitude control of ROVs or other underwater equipment operating in the complex underwater environment. In this way, the robot can better perform undersea work and tasks. Originality/value The dynamics of the ROV and the nominal control model are investigated. A novel control scheme PID-ESDOBC is proposed to achieve rapidly yaw attitude tracking and effectively reject the external disturbance. The robustness of the controller is also analyzed which provides parameters tuning guidelines. The effectiveness of the proposed controller is experimental verified with a comparison by conventional PID, ADRC.

Li-CO2 batteries are one type of promising energy storage and conversion devices to capture and utilize the greenhouse gas CO2, mitigating global temperature rise and climate change. Catalysts that could effectively decompose the discharge product, Li2CO3, are essential for high-performance Li-CO2 batteries. Benefiting from the interconnected porous structure, favorable oxygen vacancy, and the synergistic effects between the carbon nanotube (CNT) and layered birnessite δ-MnO2, our Li-CO2 cathodes with the as-prepared CNT@δ-MnO2 catalyst can efficiently afford a large reaction surface area and abundant active sites, provide sufficient electron/Li+ transport pathways, and facilitate electrolyte infiltration and CO2 diffusion, demonstrating low overpotential and superior cycling stability, which have been proven by both experimental characterization and theoretical computation. It is expected that this work can provide guidance for the design and synthesis of high-performance electrochemical catalysts for Li-CO2 batteries.

Topological conjugacy plays an important role in simplifying the systems and equations in the research of dynamical systems and functional equations. In this paper, we deal with increasing upper se...

Objective Mitochondrial dysfunction is evident in the early stage of Alzheimer’s disease (AD). Therefore development of drugs that protect mitochondrial function is a promising strategy for AD. The present work was to investigate the effects of 2, 3, 5, 4′-Tetrahydroxystilbene-2-O-β-d-glucosides (TSG) on a mitochondrial dysfunction cell model induced by sodium azide and elucidate the underlying mechanisms. Methods Mitochondrial membrane potential (MMP) was detected by a fluorescence method. Cellular adenosine triphosphate (ATP) level was measured using a firefly luciferase-based kit. Reactive oxygen species (ROS) was detected using dichlorofluorescin diacetate (DCFH-DA). The expression levels of Bcl-2 and Bax were measured by Western blotting assay. Flow cytometry was utilized to measure apoptosis. Results Pretreatment of TSG (25–200 μmol/L) for 24 h significantly elevated MMP and ATP content, reduced ROS level and Bax/Bcl-2 ratio, and inhibited apoptosis in SH-SY5Y cells exposed to sodium azide. Conclusion These results suggest that TSG protects SH-SY5Y cells against sodium azide-induced mitochondrial dysfunction and apoptosis. These findings are helpful to understand the protective effect of TSG on mitochondria, which are involved in the early stage of AD.