We recently reported that inhibitors against human dihydroorotate dehydrogenase(DHODH)have broad-spectrum antiviral activities including their inhibitory efficacies on SARS-CoV-2 replication in infected cells.However,...We recently reported that inhibitors against human dihydroorotate dehydrogenase(DHODH)have broad-spectrum antiviral activities including their inhibitory efficacies on SARS-CoV-2 replication in infected cells.However,there are limited data from clinical studies to prove the application of DHODH inhibitors in Coronavirus disease 2019(COVID-19)patients.In the present study,we evaluated Leflunomide,an approved DHODH inhibitor widely used as a modest immune regulator to treat autoimmune diseases,in treating COVID-19 disease with a small-scale of patients.Cases of 10 laboratory-confirmed COVID-19 patients of moderate type with obvious opacity in the lung were included.Five of the patients were treated with Leflunomide,and another five were treated as blank controls without a placebo.All the patients accepted standard supportive treatment for COVID-19.The patients given Leflunomide had a shorter viral shedding time(median of5 days)than the controls(median of 11 days,P=0.046).The patients given Leflunomide also showed a significant reduction in C-reactive protein levels,indicating that immunopathological inflammation was well controlled.No obvious adverse effects were observed in Leflunomide-treated patients,and they all discharged from the hospital faster than controls.This preliminary study on a small-scale compassionate use of Leflunomide provides clues for further understanding of Leflunomide as a potential antiviral drug against COVID-19.展开更多
Dear Editor,Till January 20, 2020, the 2019-new coronavirus(2019-nCoV) has caused more than one hundred cases in Wuhan(WMHC 2020). During a retrospective study of recent pneumonia patients in our department, we found ...Dear Editor,Till January 20, 2020, the 2019-new coronavirus(2019-nCoV) has caused more than one hundred cases in Wuhan(WMHC 2020). During a retrospective study of recent pneumonia patients in our department, we found two patients who are likely being infected with the 2019-nCoV.展开更多
Precipitation of calcium carbonate （CaCOs） scale on heat transfer surfaces is a serious and expensive problem widely occurring in numerous industrial processes. In this study, we compared the scale inhibition effect...Precipitation of calcium carbonate （CaCOs） scale on heat transfer surfaces is a serious and expensive problem widely occurring in numerous industrial processes. In this study, we compared the scale inhibition effect of six kinds of commercial scale inhibitors and screened out the best one （scale inhibitor SQ-1211） to investigate its scale inhibition performance in highly saline conditions at high temperature through static scale inhibition tests. The influences of scale inhibitor dosage, temperature, heating time and pH on the inhibition efficiency of the optimal scale inhibitor were investigated. The morphologies and crystal structures of the precipitates were characterized by Scanning Electron Microscopy and X-ray Diffraction analysis. Results showed that the scale inhibition efficiency of the optimal scale inhibitor decreased with the increase of the reaction temperature. When the concentration of Ca^2＋ was 1600 mg/L, the scale inhibition rate could reach 90.7% at 80℃ at pH 8. The optimal scale inhibitor could effectively retard scaling at high temperature. In the presence of the optimal scale inhibitor, the main crystal structure of CaCOs changed from calcite to aragonite.展开更多
Degradation of a metallic film under harsh thermal-mechanical-electrical coupling field conditions determines its service temperature and lifetime.In this work,the self-heating degradation behaviors of Pt thin films a...Degradation of a metallic film under harsh thermal-mechanical-electrical coupling field conditions determines its service temperature and lifetime.In this work,the self-heating degradation behaviors of Pt thin films above 1000℃were studied in situ by TEM at the nanoscale.The Pt films degraded mainly through void nucleation and growth on the Pt-SiN_(x)interface.Voids preferentially formed at the grain boundary and triple junction intersections with the interface.At temperatures above 1040℃,the voids nucleated at both the grain boundaries and inside the Pt grains.A stress simulation of the suspended membrane suggests the existence of local tensile stress in the Pt film,which promotes the nucleation of voids at the Pt-Si Nxinterface.The grain-boundary-dominated mass transportation renders the voids grow preferentially at GBs and triple junctions in a Pt film.Additionally,under the influence of an applied current,the voids that nucleated inside Pt grains grew to a large size and accelerated the degradation of the Pt film.展开更多
In this study,a stepwise oxidation system of potassium ferrate(K_(2)FeO_(4))combined with ozone(O+3)was used to degrade ciprofloxacin(CIP).The effects of pH and pre-oxidation time of K_(2)FeO_(4) on the evolution of K...In this study,a stepwise oxidation system of potassium ferrate(K_(2)FeO_(4))combined with ozone(O+3)was used to degrade ciprofloxacin(CIP).The effects of pH and pre-oxidation time of K_(2)FeO_(4) on the evolution of K_(2)FeO_(4) reduction products(iron(hydr)oxides)and CIP degradation were investigated.It was found that in addition to its own oxidation capacity,K_(2)FeO_(4) can also influence the treatment effect of CIP by changing the catalyst content.The presence of iron(hydr)oxides effectively enhanced the mineralization rate of CIP by catalyzing ozonation.The pH value can influence the content and types of the components with catalytic ozonation effect in iron(hydr)oxides.The K_(2)FeO_(4) pre-oxidation stage can produce more iron(hydr)oxides with catalytic components for subsequent ozonation,but the evolution of iron(hydr)oxides components was influenced by O_(3) treatment.It can also avoid the waste of oxidation capacity owing to the oxidation of iron(hydr)oxides by O_(3) and free radicals.The intermediate degradation products were identified by Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR-MS).Besides,the degradation pathways were proposed.Among the degradation products of CIP,the product with broken quinolone ring structure only appeared in the stepwise oxidation system.展开更多
Background:Asthma imposes a large healthcare burden in China and the United States(US).However,the trends of asthma mortality and the relative risk factors have not been comparatively analyzed between the countries.Th...Background:Asthma imposes a large healthcare burden in China and the United States(US).However,the trends of asthma mortality and the relative risk factors have not been comparatively analyzed between the countries.The aim of this study was to compare the mortality and risk factors between China and the US.Methods:The deaths,and mortality rates of asthma in China and the US during 1990–2019 were obtained from the Global Burden of Disease Study 2019.The age–period–cohort model was used to estimate these mortality rates based on a log-linear scale with additive age,period,and cohort effects.The population attributable fractions of risk factors for asthma were estimated.Results:In 1990–2019,the asthma mortality rate was higher in China than in the US.The crude and age-standardized asthma mortality rates trended downward in both China and the US from 1990 to 2019.The decline in mortality was more obvious in China.Mortality gap between the two countries was narrowing.A sex difference in asthma mortality was observed with higher mortality in males in China and females in the US.The age effects showed that mortality increased with age in adults older than 20 years,particularly in the elderly.Downward trends were generally observed in the period and cohort rate ratios in both countries,with China experiencing a more obvious decrease.Smoking and high body mass index(BMI)were the leading risk factors for asthma mortality in China and the US,respectively.Mortality attributable to occupational asthmagens and smoking decreased the most in China and the US,respectively.Conclusions:In 1990–2019,the asthma mortality rate was higher in China than in the US;however,the mortality gap has narrowed.Mortality increased with age in adults.The improvements in asthma death risk with period and birth cohort were more obvious in China than in the US.Smoking,high BMI,and aging are major health problems associated with asthma control.The role of occupational asthmagens in asthma mortality underscores the importance of management and prevention of occupational asthma.展开更多
Lead halide perovskites MAPbX_(3)(MA = CH_(3)NH_(3) or Cs;X = I, Br, Cl) are well considered to be potential candidates for photocatalytic reaction due to its excellent photoelectrical properties, but they still suffe...Lead halide perovskites MAPbX_(3)(MA = CH_(3)NH_(3) or Cs;X = I, Br, Cl) are well considered to be potential candidates for photocatalytic reaction due to its excellent photoelectrical properties, but they still suffer from the low charge separation efficiency and slow catalytic reaction dynamics. To tackle the drawbacks, herein, MAPbBr_(3)/carbon sphere(CS) composite photocatalysts using glucose as the carbon source were elaborately designed and fabricated via a dry mechanochemical grinding process. The interfacial interaction Pb-O-C chemical bonds were constructed between MAPbBr_(3) and the carbon sphere surface containing organic functional groups. By optimizing the content of CSs, the enhanced photocatalytic degradation kinetic rate of Malachite Green(MG) pollutants(92% within 20 min) for MAPbBr_(3)/CS x( x = 17 wt.%) is about 3.6-fold of that for pristine MAPbBr_(3), which is attributed to the corporative adsorption and enhanced carrier transportation and separation of MAPbBr_(3)/CS x. Furthermore, the possible degradation mechanism was proposed on basis of the electrochemical, mass spectrometry and optical characterization results. Owing to the robust interfacial interaction, effective electron extraction rate( k et = 4.6 × 10^(7) sec^(-1)) from MAPbBr_(3) to CS can be established, which driven oxygen activation where superoxide radicals(·O^(2-)) played an important role in MG degradation. It is expected that mechanochemistry strategy may provide a new route to design efficient lead halide perovskite-carbon or metal oxide or sulfide composite photocatalysts.展开更多
A novel real-time autonomous Interval Management System(IMS)is proposed to automate interval management,which considers the effect of wind uncertainty using the Dynamic Fuzzy Velocity Decision(DFVD)algorithm.The membe...A novel real-time autonomous Interval Management System(IMS)is proposed to automate interval management,which considers the effect of wind uncertainty using the Dynamic Fuzzy Velocity Decision(DFVD)algorithm.The membership function can be generated dynamically based on the True Air Speed(TAS)limitation changes in real time and the interval criterion of the adjacent aircraft,and combined with human cognition to formulate fuzzy rules for speed adjusting decision-making.Three groups of experiments were conducted during the en-route descent stage to validate the proposed IMS and DFVD performances,and to analyze the impact factors of the algorithm.The verification experimental results show that compared with actual flight status data under controllers’command,the IMS reduces the descent time by approaching 30%with favorable wind uncertainty suppression performance.Sensitivity analysis shows that the ability improvement of DFVD is mainly affected by the boundary value of the membership function.Additionally,the dynamic generation of the velocity membership function has greater advantages than the static method in terms of safety and stability.Through the analysis of influencing factors,we found that the interval criterion and aircraft category have no significant effect on the capability of IMS.In a higher initial altitude scenario,the initial interval should be appropriately increased to enhance safety and efficiency during the descent process.This prototype system could evolve into a realtime Flight-deck Interval Management(FIM)tool in the future.展开更多
The seafloor vector magnetometer is an effective tool for marine geomagnetic surveys and seafloor magnetotelluric(MT)detection.However,the noise,power consumption,cost,and volume characteristics of existing seafloor v...The seafloor vector magnetometer is an effective tool for marine geomagnetic surveys and seafloor magnetotelluric(MT)detection.However,the noise,power consumption,cost,and volume characteristics of existing seafloor vector magnetometers are insufficient for practical use.Therefore,a low-noise,low-power-consumption seafloor vector magnetometer that can be used for data acquisition of deep-ocean geomagnetic vector components is developed and presented.A seafloor vector magnetometer mainly consists of a fluxgate sensor,data acquisition module,acoustic release module,glass sphere,frame,burn-wire release,and anchor.A new low-noise data acquisition module and a fluxgate sensor greatly reduce power consumption.Furthermore,compact size is achieved by integrating an acoustic telemetry module and replacing the acoustic release with an external burn-wire release.The new design and magnetometer characteristics reduce the volume of the instrument and the cost of hardware considerably,thereby improving the integrity and deployment efficiency of the equipment.Theoretically,it can operate for 90 days underwater at a maximum depth of 6000 m.The seafloor vector magnetometer was tested in the South China Sea and the Philippine Sea and obtained high-quality geomagnetic data.The deep-water environment facilitates magnetic field data measurements,and the magnetometer has an approximate noise level of 10 pT/rt(Hz)@1 Hz,a peak-to-peak value error of 0.2 nT,and approximate power consumption of 200 mW.The fluxgate sensor can measure the magnetic field in the lower frequency band and realize geomagnetic field measurements over prolonged periods.展开更多
1 Introduction On-device deep learning(DL)on mobile and embedded IoT devices drives various applications[1]like robotics image recognition[2]and drone swarm classification[3].Efficient local data processing preserves ...1 Introduction On-device deep learning(DL)on mobile and embedded IoT devices drives various applications[1]like robotics image recognition[2]and drone swarm classification[3].Efficient local data processing preserves privacy,enhances responsiveness,and saves bandwidth.However,current ondevice DL relies on predefined patterns,leading to accuracy and efficiency bottlenecks.It is difficult to provide feedback on data processing performance during the data acquisition stage,as processing typically occurs after data acquisition.展开更多
Common buckwheat(Fagopyrum esculentum)and Tartary buckwheat(Fagopyrum tataricum),the two most widely cultivated buckwheat species,differ greatly in flavonoid content and reproductive mode.Here,we report the first high...Common buckwheat(Fagopyrum esculentum)and Tartary buckwheat(Fagopyrum tataricum),the two most widely cultivated buckwheat species,differ greatly in flavonoid content and reproductive mode.Here,we report the first high-quality and chromosome-level genome assembly of common buckwheat with 1.2 Gb.Comparative genomic analysis revealed that common buckwheat underwent a burst of long terminal repeat retrotransposons insertion accompanied by numerous large chromosome rearrangements after divergence from Tartary buckwheat.Moreover,multiple gene families involved in stress tolerance and flavonoid biosynthesis such as multidrug and toxic compound extrusion(MATE)and chalcone synthase(CHS)underwent significant expansion in buckwheat,especially in common buckwheat.Integrated multi-omics analysis identified high expression of catechin biosynthesis-related genes in flower and seed in common buckwheat and high expression of rutin biosynthesis-related genes in seed in Tartary buckwheat as being important for the differences in flavonoid type and content between these buckwheat species.We also identified a candidate key rutindegrading enzyme gene(Ft8.2377)that was highly expressed in Tartary buckwheat seed.In addition,we identified a haplotype-resolved candidate locus containing many genes reportedly associated with the development of flower and pollen,which was potentially related to self-incompatibility in common buckwheat.Our study provides important resources facilitating future functional genomics-related research of flavonoid biosynthesis and selfincompatibility in buckwheat.展开更多
A new class of backward particle systems with sequential interaction is proposed to approximate the mean-field backward stochastic differential equations.It is proven that the weighted empirical measure of this partic...A new class of backward particle systems with sequential interaction is proposed to approximate the mean-field backward stochastic differential equations.It is proven that the weighted empirical measure of this particle system converges to the law of the McKean-Vlasov system as the number of particles grows.Based on the Wasserstein met-ric,quantitative propagation of chaos results are obtained for both linear and quadratic growth conditions.Finally,numerical experiments are conducted to validate our theoretical results.展开更多
The severity of climate change and global warming necessitates the need for a transition from traditional hydrocarbon-based energy sources to renewable energy sources.One intrinsic challenge with renewable energy sour...The severity of climate change and global warming necessitates the need for a transition from traditional hydrocarbon-based energy sources to renewable energy sources.One intrinsic challenge with renewable energy sources is their intermittent nature,which can be addressed by transforming excess energy into hydrogen and storing it safely for future use.To securely store hydrogen underground,a comprehensive knowledge of the interactions between hydrogen and residing fluids is required.Interfacial tension is an important variable influenced by cushion gases such as CO_(2) and CH4.This research developed explicit correlations for approximating the interfacial tension of a hydrogen–brine mixture using two advanced machine-learning techniques:gene expression programming and the group method of data handling.The interfacial tension of a hydrogen–brine mixture was considered to be heavily influenced by temperature,pressure,water salinity,and the average critical temperature of the gas mixture.The results indicated a higher performance of the group method of data handling-based correlation,showing an average absolute relative error of 4.53%.Subsequently,Pearson,Spearman,and Kendall methods were used to assess the influence of individual input variables on the outputs of the correlations.Analysis showed that the temperature and the average critical temperature of the gas mixture had considerable inverse impacts on the estimated interfacial tension values.Finally,the reliability of the gathered databank and the scope of application for the proposed correlations were verified using the leverage approach by illustrating 97.6%of the gathered data within the valid range of the Williams plot.展开更多
Recent studies have applied different approaches for summarizing software artifacts, and yet very few efforts have been made in summarizing the source code fragments available on web. This paper investigates the feasi...Recent studies have applied different approaches for summarizing software artifacts, and yet very few efforts have been made in summarizing the source code fragments available on web. This paper investigates the feasibility of generating code fragment summaries by using supervised learning algorithms. We hire a crowd of ten individuals from the same work place to extract source code features on a cor- pus of 127 code fragments retrieved from Eclipse and Net- Beans Official frequently asked questions （FAQs）. Human an- notators suggest summary lines. Our machine learning algo- rithms produce better results with the precision of 82% and perform statistically better than existing code fragment classi- fiers. Evaluation of algorithms on several statistical measures endorses our result. This result is promising when employing mechanisms such as data-driven crowd enlistment improve the efficacy of existing code fragment classifiers.展开更多
Inhibiting the irreversible escape of organic cations and iodide species in perovskite films is crucial for the fabrication of efficient and stable perovskite solar cells(PSCs).Here,we develop a reaction-and-assembly ...Inhibiting the irreversible escape of organic cations and iodide species in perovskite films is crucial for the fabrication of efficient and stable perovskite solar cells(PSCs).Here,we develop a reaction-and-assembly approach using monoamine zinc porphyrin(ZnP)to modify methylammonium(MA^+)lead iodide perovskite film.The amine group in ZnP reacts with MA^+and I^-ions to yield monoammonium zinc porphyrin(ZnP-H+I-).The resultant films show no escape of iodide when immersed in ether solutions.Measurements from space-charge limited currents and transient photoluminescence indicate the modified films have reduced density of defects.These results suggest the formed ZnP-H^+I^-is bound on the surface and grain boundary of perovskite film to retard migrations of ions.DFT calculations also show that the energy alignment between ZnP-H^+and perovskite facilitates the electron transfer and reduces charge recombination at the perovskite grains.Furthermore,post-treating the Zn Pdoped film with ZnP again results in the formation of a one dimension zig-zag coordination polymer on the surface of the perovskite film.The single crystal structure of ZnP shows the polymer layer is formed through the coordination interaction between the Zn(II)metal center and a neighboring monoamine.The polymer facilitates the interfacial charge transfer,and reduces the escape of organic cations and iodide species in perovskite films,thereby keeping the excellent cell performance(20.0%)and further realizing the ion encapsulation.Finally,the modified PSCs retain over 90%of its original efficiency over2,000 h at 85°C or AM 1.5 G continuous illumination,or over 6,000 h in 45%humidity without encapsulation.This work affords a new strategy to achieve the efficient ions immobilization and encapsulation by in situ reaction and coordination assembly of mono-amine zinc porphyrin.展开更多
Group behavior forecasting is an emergent re- search and application field in social computing. Most of the existing group behavior forecasting methods have heavily re- lied on structured data which is usually hard to...Group behavior forecasting is an emergent re- search and application field in social computing. Most of the existing group behavior forecasting methods have heavily re- lied on structured data which is usually hard to obtain. To ease the heavy reliance on structured data, in this paper, we pro- pose a computational approach based on the recognition of multiple plans/intentions underlying group behavior. We fur- ther conduct human experiment to empirically evaluate the effectiveness of our proposed approach.展开更多
The effect of container geometry on the Faraday waves in Hele-Shaw cells has been investigated. The wave heights increase with the width of the cell and a linear function is selected to express the relation between th...The effect of container geometry on the Faraday waves in Hele-Shaw cells has been investigated. The wave heights increase with the width of the cell and a linear function is selected to express the relation between these data and parameters. The wave lengths also increase with the width and are in good agreement with the dispersion relation. In order to reveal the real nature behind these phenomena, we have developed a gap-averaged model to numerically solve this issue and give an analysis of the result to show how these Faraday waves are formed in a Hele-Shaw cell.展开更多
基金supported by the Science and Technology Key Project on Novel Coronavirus Pneumonia,Hubei Province(project number:2020FCA002 to K.H.)the Application&Frontier Research Program of Wuhan Government(2019020701011463 to K.X.)+2 种基金Taikang Insurance Group Co.,LtdBeijing Taikang Yicai FoundationSpecial Fund for COVID-19 Research of Wuhan University for their great supports to this work。
文摘We recently reported that inhibitors against human dihydroorotate dehydrogenase(DHODH)have broad-spectrum antiviral activities including their inhibitory efficacies on SARS-CoV-2 replication in infected cells.However,there are limited data from clinical studies to prove the application of DHODH inhibitors in Coronavirus disease 2019(COVID-19)patients.In the present study,we evaluated Leflunomide,an approved DHODH inhibitor widely used as a modest immune regulator to treat autoimmune diseases,in treating COVID-19 disease with a small-scale of patients.Cases of 10 laboratory-confirmed COVID-19 patients of moderate type with obvious opacity in the lung were included.Five of the patients were treated with Leflunomide,and another five were treated as blank controls without a placebo.All the patients accepted standard supportive treatment for COVID-19.The patients given Leflunomide had a shorter viral shedding time(median of5 days)than the controls(median of 11 days,P=0.046).The patients given Leflunomide also showed a significant reduction in C-reactive protein levels,indicating that immunopathological inflammation was well controlled.No obvious adverse effects were observed in Leflunomide-treated patients,and they all discharged from the hospital faster than controls.This preliminary study on a small-scale compassionate use of Leflunomide provides clues for further understanding of Leflunomide as a potential antiviral drug against COVID-19.
基金supported by the strategic priority research program of the Chinese academy of sciences (XDB29010101 to ZLS)。
文摘Dear Editor,Till January 20, 2020, the 2019-new coronavirus(2019-nCoV) has caused more than one hundred cases in Wuhan(WMHC 2020). During a retrospective study of recent pneumonia patients in our department, we found two patients who are likely being infected with the 2019-nCoV.
基金supported by the Major Bidding Projects in Shandong Province (No. SDZS-2012-SHBT01)
文摘Precipitation of calcium carbonate （CaCOs） scale on heat transfer surfaces is a serious and expensive problem widely occurring in numerous industrial processes. In this study, we compared the scale inhibition effect of six kinds of commercial scale inhibitors and screened out the best one （scale inhibitor SQ-1211） to investigate its scale inhibition performance in highly saline conditions at high temperature through static scale inhibition tests. The influences of scale inhibitor dosage, temperature, heating time and pH on the inhibition efficiency of the optimal scale inhibitor were investigated. The morphologies and crystal structures of the precipitates were characterized by Scanning Electron Microscopy and X-ray Diffraction analysis. Results showed that the scale inhibition efficiency of the optimal scale inhibitor decreased with the increase of the reaction temperature. When the concentration of Ca^2＋ was 1600 mg/L, the scale inhibition rate could reach 90.7% at 80℃ at pH 8. The optimal scale inhibitor could effectively retard scaling at high temperature. In the presence of the optimal scale inhibitor, the main crystal structure of CaCOs changed from calcite to aragonite.
基金financially supported by the Basic Science Center Program for Multiphase Evolution in Hyper-gravity of the National Natural Science Foundation of China(51988101)NSFC Programs(Nos.52071003,91860202,11604006)+3 种基金the Beijing Municipal Education Commission Project(Nos.PXM2020014204000021 and PXM201901420400032)the Beijing Outstanding Young Scientists Projects(No.BJJWZYJH01201910005018)the Beijing Natural Science Foundation(No.Z180014)the“111 Project(No.DB18015)。
文摘Degradation of a metallic film under harsh thermal-mechanical-electrical coupling field conditions determines its service temperature and lifetime.In this work,the self-heating degradation behaviors of Pt thin films above 1000℃were studied in situ by TEM at the nanoscale.The Pt films degraded mainly through void nucleation and growth on the Pt-SiN_(x)interface.Voids preferentially formed at the grain boundary and triple junction intersections with the interface.At temperatures above 1040℃,the voids nucleated at both the grain boundaries and inside the Pt grains.A stress simulation of the suspended membrane suggests the existence of local tensile stress in the Pt film,which promotes the nucleation of voids at the Pt-Si Nxinterface.The grain-boundary-dominated mass transportation renders the voids grow preferentially at GBs and triple junctions in a Pt film.Additionally,under the influence of an applied current,the voids that nucleated inside Pt grains grew to a large size and accelerated the degradation of the Pt film.
基金supported by the National Natural Science Foundation of China (No.51878394)the Introduction and Cultivation Plan for Young Innovative Talents of Colleges and Universities by the Education Department of Shandong Province。
文摘In this study,a stepwise oxidation system of potassium ferrate(K_(2)FeO_(4))combined with ozone(O+3)was used to degrade ciprofloxacin(CIP).The effects of pH and pre-oxidation time of K_(2)FeO_(4) on the evolution of K_(2)FeO_(4) reduction products(iron(hydr)oxides)and CIP degradation were investigated.It was found that in addition to its own oxidation capacity,K_(2)FeO_(4) can also influence the treatment effect of CIP by changing the catalyst content.The presence of iron(hydr)oxides effectively enhanced the mineralization rate of CIP by catalyzing ozonation.The pH value can influence the content and types of the components with catalytic ozonation effect in iron(hydr)oxides.The K_(2)FeO_(4) pre-oxidation stage can produce more iron(hydr)oxides with catalytic components for subsequent ozonation,but the evolution of iron(hydr)oxides components was influenced by O_(3) treatment.It can also avoid the waste of oxidation capacity owing to the oxidation of iron(hydr)oxides by O_(3) and free radicals.The intermediate degradation products were identified by Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR-MS).Besides,the degradation pathways were proposed.Among the degradation products of CIP,the product with broken quinolone ring structure only appeared in the stepwise oxidation system.
文摘Background:Asthma imposes a large healthcare burden in China and the United States(US).However,the trends of asthma mortality and the relative risk factors have not been comparatively analyzed between the countries.The aim of this study was to compare the mortality and risk factors between China and the US.Methods:The deaths,and mortality rates of asthma in China and the US during 1990–2019 were obtained from the Global Burden of Disease Study 2019.The age–period–cohort model was used to estimate these mortality rates based on a log-linear scale with additive age,period,and cohort effects.The population attributable fractions of risk factors for asthma were estimated.Results:In 1990–2019,the asthma mortality rate was higher in China than in the US.The crude and age-standardized asthma mortality rates trended downward in both China and the US from 1990 to 2019.The decline in mortality was more obvious in China.Mortality gap between the two countries was narrowing.A sex difference in asthma mortality was observed with higher mortality in males in China and females in the US.The age effects showed that mortality increased with age in adults older than 20 years,particularly in the elderly.Downward trends were generally observed in the period and cohort rate ratios in both countries,with China experiencing a more obvious decrease.Smoking and high body mass index(BMI)were the leading risk factors for asthma mortality in China and the US,respectively.Mortality attributable to occupational asthmagens and smoking decreased the most in China and the US,respectively.Conclusions:In 1990–2019,the asthma mortality rate was higher in China than in the US;however,the mortality gap has narrowed.Mortality increased with age in adults.The improvements in asthma death risk with period and birth cohort were more obvious in China than in the US.Smoking,high BMI,and aging are major health problems associated with asthma control.The role of occupational asthmagens in asthma mortality underscores the importance of management and prevention of occupational asthma.
文摘Lead halide perovskites MAPbX_(3)(MA = CH_(3)NH_(3) or Cs;X = I, Br, Cl) are well considered to be potential candidates for photocatalytic reaction due to its excellent photoelectrical properties, but they still suffer from the low charge separation efficiency and slow catalytic reaction dynamics. To tackle the drawbacks, herein, MAPbBr_(3)/carbon sphere(CS) composite photocatalysts using glucose as the carbon source were elaborately designed and fabricated via a dry mechanochemical grinding process. The interfacial interaction Pb-O-C chemical bonds were constructed between MAPbBr_(3) and the carbon sphere surface containing organic functional groups. By optimizing the content of CSs, the enhanced photocatalytic degradation kinetic rate of Malachite Green(MG) pollutants(92% within 20 min) for MAPbBr_(3)/CS x( x = 17 wt.%) is about 3.6-fold of that for pristine MAPbBr_(3), which is attributed to the corporative adsorption and enhanced carrier transportation and separation of MAPbBr_(3)/CS x. Furthermore, the possible degradation mechanism was proposed on basis of the electrochemical, mass spectrometry and optical characterization results. Owing to the robust interfacial interaction, effective electron extraction rate( k et = 4.6 × 10^(7) sec^(-1)) from MAPbBr_(3) to CS can be established, which driven oxygen activation where superoxide radicals(·O^(2-)) played an important role in MG degradation. It is expected that mechanochemistry strategy may provide a new route to design efficient lead halide perovskite-carbon or metal oxide or sulfide composite photocatalysts.
文摘A novel real-time autonomous Interval Management System(IMS)is proposed to automate interval management,which considers the effect of wind uncertainty using the Dynamic Fuzzy Velocity Decision(DFVD)algorithm.The membership function can be generated dynamically based on the True Air Speed(TAS)limitation changes in real time and the interval criterion of the adjacent aircraft,and combined with human cognition to formulate fuzzy rules for speed adjusting decision-making.Three groups of experiments were conducted during the en-route descent stage to validate the proposed IMS and DFVD performances,and to analyze the impact factors of the algorithm.The verification experimental results show that compared with actual flight status data under controllers’command,the IMS reduces the descent time by approaching 30%with favorable wind uncertainty suppression performance.Sensitivity analysis shows that the ability improvement of DFVD is mainly affected by the boundary value of the membership function.Additionally,the dynamic generation of the velocity membership function has greater advantages than the static method in terms of safety and stability.Through the analysis of influencing factors,we found that the interval criterion and aircraft category have no significant effect on the capability of IMS.In a higher initial altitude scenario,the initial interval should be appropriately increased to enhance safety and efficiency during the descent process.This prototype system could evolve into a realtime Flight-deck Interval Management(FIM)tool in the future.
基金Supported by the Guangdong Special Support Talent Team Program(No.2019BT02H594)the National Natural Science Foundation of China(Nos.42174081,41804071,U2244221)the Guangdong Basic and Applied Basic Research Foundation(No.2021A1515011526)。
文摘The seafloor vector magnetometer is an effective tool for marine geomagnetic surveys and seafloor magnetotelluric(MT)detection.However,the noise,power consumption,cost,and volume characteristics of existing seafloor vector magnetometers are insufficient for practical use.Therefore,a low-noise,low-power-consumption seafloor vector magnetometer that can be used for data acquisition of deep-ocean geomagnetic vector components is developed and presented.A seafloor vector magnetometer mainly consists of a fluxgate sensor,data acquisition module,acoustic release module,glass sphere,frame,burn-wire release,and anchor.A new low-noise data acquisition module and a fluxgate sensor greatly reduce power consumption.Furthermore,compact size is achieved by integrating an acoustic telemetry module and replacing the acoustic release with an external burn-wire release.The new design and magnetometer characteristics reduce the volume of the instrument and the cost of hardware considerably,thereby improving the integrity and deployment efficiency of the equipment.Theoretically,it can operate for 90 days underwater at a maximum depth of 6000 m.The seafloor vector magnetometer was tested in the South China Sea and the Philippine Sea and obtained high-quality geomagnetic data.The deep-water environment facilitates magnetic field data measurements,and the magnetometer has an approximate noise level of 10 pT/rt(Hz)@1 Hz,a peak-to-peak value error of 0.2 nT,and approximate power consumption of 200 mW.The fluxgate sensor can measure the magnetic field in the lower frequency band and realize geomagnetic field measurements over prolonged periods.
基金supported by the National Science Fund for Distinguished Young Scholars(62025205)the National Natural Science Foundation of China(Grant Nos.62032020,62102317)CityU APRC Grant(9610633).
文摘1 Introduction On-device deep learning(DL)on mobile and embedded IoT devices drives various applications[1]like robotics image recognition[2]and drone swarm classification[3].Efficient local data processing preserves privacy,enhances responsiveness,and saves bandwidth.However,current ondevice DL relies on predefined patterns,leading to accuracy and efficiency bottlenecks.It is difficult to provide feedback on data processing performance during the data acquisition stage,as processing typically occurs after data acquisition.
基金supported by the National Natural Science Foundation of China(32100500)Natural Science Foundation of Hebei Province(C2021201048)supported by the fund from the State Key Laboratory of Plant Genomics and the Chinese Academy of Sciences(CASWX2021SF-0109)。
文摘Common buckwheat(Fagopyrum esculentum)and Tartary buckwheat(Fagopyrum tataricum),the two most widely cultivated buckwheat species,differ greatly in flavonoid content and reproductive mode.Here,we report the first high-quality and chromosome-level genome assembly of common buckwheat with 1.2 Gb.Comparative genomic analysis revealed that common buckwheat underwent a burst of long terminal repeat retrotransposons insertion accompanied by numerous large chromosome rearrangements after divergence from Tartary buckwheat.Moreover,multiple gene families involved in stress tolerance and flavonoid biosynthesis such as multidrug and toxic compound extrusion(MATE)and chalcone synthase(CHS)underwent significant expansion in buckwheat,especially in common buckwheat.Integrated multi-omics analysis identified high expression of catechin biosynthesis-related genes in flower and seed in common buckwheat and high expression of rutin biosynthesis-related genes in seed in Tartary buckwheat as being important for the differences in flavonoid type and content between these buckwheat species.We also identified a candidate key rutindegrading enzyme gene(Ft8.2377)that was highly expressed in Tartary buckwheat seed.In addition,we identified a haplotype-resolved candidate locus containing many genes reportedly associated with the development of flower and pollen,which was potentially related to self-incompatibility in common buckwheat.Our study provides important resources facilitating future functional genomics-related research of flavonoid biosynthesis and selfincompatibility in buckwheat.
基金supported by the National Natural Science Foundation of China(No.12222103)the National Key R&D Program of China(No.2018YFA0703900).
文摘A new class of backward particle systems with sequential interaction is proposed to approximate the mean-field backward stochastic differential equations.It is proven that the weighted empirical measure of this particle system converges to the law of the McKean-Vlasov system as the number of particles grows.Based on the Wasserstein met-ric,quantitative propagation of chaos results are obtained for both linear and quadratic growth conditions.Finally,numerical experiments are conducted to validate our theoretical results.
文摘The severity of climate change and global warming necessitates the need for a transition from traditional hydrocarbon-based energy sources to renewable energy sources.One intrinsic challenge with renewable energy sources is their intermittent nature,which can be addressed by transforming excess energy into hydrogen and storing it safely for future use.To securely store hydrogen underground,a comprehensive knowledge of the interactions between hydrogen and residing fluids is required.Interfacial tension is an important variable influenced by cushion gases such as CO_(2) and CH4.This research developed explicit correlations for approximating the interfacial tension of a hydrogen–brine mixture using two advanced machine-learning techniques:gene expression programming and the group method of data handling.The interfacial tension of a hydrogen–brine mixture was considered to be heavily influenced by temperature,pressure,water salinity,and the average critical temperature of the gas mixture.The results indicated a higher performance of the group method of data handling-based correlation,showing an average absolute relative error of 4.53%.Subsequently,Pearson,Spearman,and Kendall methods were used to assess the influence of individual input variables on the outputs of the correlations.Analysis showed that the temperature and the average critical temperature of the gas mixture had considerable inverse impacts on the estimated interfacial tension values.Finally,the reliability of the gathered databank and the scope of application for the proposed correlations were verified using the leverage approach by illustrating 97.6%of the gathered data within the valid range of the Williams plot.
基金We would like to extend our gratitude to the individu- als who dedicated their time and effort to participate in crowdsourcing activ- ity and annotation of our code fragment corpus. This work was supported in part by National Program on Key Basic Research Project （2013CB035906）, in part by the New Century Excellent Talents in University （NCET-13-0073）, and in part by the National Natural Science Foundation of China （Grant Nos. 61175062, 61370144）.
文摘Recent studies have applied different approaches for summarizing software artifacts, and yet very few efforts have been made in summarizing the source code fragments available on web. This paper investigates the feasibility of generating code fragment summaries by using supervised learning algorithms. We hire a crowd of ten individuals from the same work place to extract source code features on a cor- pus of 127 code fragments retrieved from Eclipse and Net- Beans Official frequently asked questions （FAQs）. Human an- notators suggest summary lines. Our machine learning algo- rithms produce better results with the precision of 82% and perform statistically better than existing code fragment classi- fiers. Evaluation of algorithms on several statistical measures endorses our result. This result is promising when employing mechanisms such as data-driven crowd enlistment improve the efficacy of existing code fragment classifiers.
基金supported by the National Natural Science Foundation of China(21801104,21871121,21431002)the Young Elite Scientists Sponsorship Program by China Association for Science and Technology(2018QNRC001)+3 种基金the Fundamental Research Funds for the Central Universities of China(lzujbky-2019-sp01,lzujbky-2019-kb12)the Special Fund Project of Guiding Scientific and Technological Innovation Development of Gansu Province(2019ZX-04)support by the US Department of Energy(DE-FG02-07ER46427)support of Gansu Computing Center of China。
文摘Inhibiting the irreversible escape of organic cations and iodide species in perovskite films is crucial for the fabrication of efficient and stable perovskite solar cells(PSCs).Here,we develop a reaction-and-assembly approach using monoamine zinc porphyrin(ZnP)to modify methylammonium(MA^+)lead iodide perovskite film.The amine group in ZnP reacts with MA^+and I^-ions to yield monoammonium zinc porphyrin(ZnP-H+I-).The resultant films show no escape of iodide when immersed in ether solutions.Measurements from space-charge limited currents and transient photoluminescence indicate the modified films have reduced density of defects.These results suggest the formed ZnP-H^+I^-is bound on the surface and grain boundary of perovskite film to retard migrations of ions.DFT calculations also show that the energy alignment between ZnP-H^+and perovskite facilitates the electron transfer and reduces charge recombination at the perovskite grains.Furthermore,post-treating the Zn Pdoped film with ZnP again results in the formation of a one dimension zig-zag coordination polymer on the surface of the perovskite film.The single crystal structure of ZnP shows the polymer layer is formed through the coordination interaction between the Zn(II)metal center and a neighboring monoamine.The polymer facilitates the interfacial charge transfer,and reduces the escape of organic cations and iodide species in perovskite films,thereby keeping the excellent cell performance(20.0%)and further realizing the ion encapsulation.Finally,the modified PSCs retain over 90%of its original efficiency over2,000 h at 85°C or AM 1.5 G continuous illumination,or over 6,000 h in 45%humidity without encapsulation.This work affords a new strategy to achieve the efficient ions immobilization and encapsulation by in situ reaction and coordination assembly of mono-amine zinc porphyrin.
文摘Group behavior forecasting is an emergent re- search and application field in social computing. Most of the existing group behavior forecasting methods have heavily re- lied on structured data which is usually hard to obtain. To ease the heavy reliance on structured data, in this paper, we pro- pose a computational approach based on the recognition of multiple plans/intentions underlying group behavior. We fur- ther conduct human experiment to empirically evaluate the effectiveness of our proposed approach.
基金supported by the National Natural Science Foundation of China(Grant No.11702099)the China Postdoctoral Science Foundation(Grant No.2017M612670)
文摘The effect of container geometry on the Faraday waves in Hele-Shaw cells has been investigated. The wave heights increase with the width of the cell and a linear function is selected to express the relation between these data and parameters. The wave lengths also increase with the width and are in good agreement with the dispersion relation. In order to reveal the real nature behind these phenomena, we have developed a gap-averaged model to numerically solve this issue and give an analysis of the result to show how these Faraday waves are formed in a Hele-Shaw cell.
