Electronic waste(e-waste)and diabetes are global challenges to modern societies.However,solving these two challenges together has been challenging until now.Herein,we propose a laser-induced transfer method to fabrica...Electronic waste(e-waste)and diabetes are global challenges to modern societies.However,solving these two challenges together has been challenging until now.Herein,we propose a laser-induced transfer method to fabricate portable glucose sensors by recycling copper from e-waste.We bring up a laser-induced full-automatic fabrication method for synthesizing continuous heterogeneous Cu_(x)O(h-Cu_(x)O)nano-skeletons electrode for glucose sensing,offering rapid(<1 min),clean,air-compatible,and continuous fabrication,applicable to a wide range of Cu-containing substrates.Leveraging this approach,h-Cu_(x)O nanoskeletons,with an inner core predominantly composed of Cu_(2)O with lower oxygen content,juxtaposed with an outer layer rich in amorphous Cu_(x)O(a-Cu_(x)O)with higher oxygen content,are derived from discarded printed circuit boards.When employed in glucose detection,the h-Cu_(x)O nano-skeletons undergo a structural evolution process,transitioning into rigid Cu_(2)O@CuO nano-skeletons prompted by electrochemical activation.This transformation yields exceptional glucose-sensing performance(sensitivity:9.893 mA mM^(-1) cm^(-2);detection limit:0.34μM),outperforming most previously reported glucose sensors.Density functional theory analysis elucidates that the heterogeneous structure facilitates gluconolactone desorption.This glucose detection device has also been downsized to optimize its scalability and portability for convenient integration into people’s everyday lives.展开更多
Due to the considerable uncertainties inherent in the datasets describing the spatiotemporal distributions of precipitation in the drylands of China,this study presents a new merged monthly precipitation product with ...Due to the considerable uncertainties inherent in the datasets describing the spatiotemporal distributions of precipitation in the drylands of China,this study presents a new merged monthly precipitation product with a spatial resolution of approximately 0.2°×0.2°during 1980–2019.The newly developed precipitation product was validated at different temporal scales(e.g.,monthly,seasonally,and annually).The results show that the new product consistently aligns with the spatiotemporal distributions reported by the Chinese Meteorological Administration Land Data Assimilation System(CLDAS)product and Multi-Source Weighted Ensemble Precipitation(MSWEP).The merged product exhibits exceptional quality in describing the drylands of China,with a bias of–2.19 mm month^(–1)relative to MSWEP.In addition,the annual trend of the merged product(0.09 mm month^(–1)yr^(−1))also closely aligns with that of the MSWEP(0.11 mm month^(–1)yr^(−1))during 1980–2019.The increasing trend indicates that the water cycle and wetting process intensified in the drylands of China during this period.In particular,there was an increase in wetting during the period from 2001–2019.Generally,the merged product exhibits potential value for improving our understanding of the climate and water cycle in the drylands of China.展开更多
Dust storms are one of the most frequent meteorological disasters in China,endangering agricultural production,transportation,air quality,and the safety of people’s lives and property.Against the backdrop of climate ...Dust storms are one of the most frequent meteorological disasters in China,endangering agricultural production,transportation,air quality,and the safety of people’s lives and property.Against the backdrop of climate change,Mongolia’s contribution to China’s dust cannot be ignored in recent years.In this study,we used the Weather Research and Forecasting model coupled with Chemistry(WRF-Chem),along with dynamic dust sources and the HYSPLIT model,to analyze the contributions of different dust sources to dust concentrations in northern China in March and April 2023.The results show that the frequency of dust storms in 2023 was the highest observed in the past decade.Mongolia and the Taklimakan Desert were identified as two main dust sources contributing to northern China.Specifically,Mongolia contributed more than 42%of dust,while the Taklimakan Desert accounted for 26%.A cold high-pressure center,a cold front,and a Mongolian cyclone resulted in the transport of dust aerosols from Mongolia and the Taklimakan Desert to northern China,where they affected most parts of the region.Moreover,two machine learning methods[the XGBoost algorithm and the Synthetic Minority Oversampling Technique(SMOTE)]were used to forecast the dust storms in March 2023,based on ground observations and WRF-Chem simulations over East Asia.XGBoost-SMOTE performed well in predicting hourly PM10 concentrations in China in March 2023,with a mean absolute error of 33.8μg m−3 and RMSE of 54.2μg m−3.展开更多
Unmanned Aerial Vehicle(UAV)has emerged as a promising technology for the support of human activities,such as target tracking,disaster rescue,and surveillance.However,these tasks require a large computation load of im...Unmanned Aerial Vehicle(UAV)has emerged as a promising technology for the support of human activities,such as target tracking,disaster rescue,and surveillance.However,these tasks require a large computation load of image or video processing,which imposes enormous pressure on the UAV computation platform.To solve this issue,in this work,we propose an intelligent Task Offloading Algorithm(iTOA)for UAV edge computing network.Compared with existing methods,iTOA is able to perceive the network’s environment intelligently to decide the offloading action based on deep Monte Calor Tree Search(MCTS),the core algorithm of Alpha Go.MCTS will simulate the offloading decision trajectories to acquire the best decision by maximizing the reward,such as lowest latency or power consumption.To accelerate the search convergence of MCTS,we also proposed a splitting Deep Neural Network(sDNN)to supply the prior probability for MCTS.The sDNN is trained by a self-supervised learning manager.Here,the training data set is obtained from iTOA itself as its own teacher.Compared with game theory and greedy search-based methods,the proposed iTOA improves service latency performance by 33%and 60%,respectively.展开更多
C18 ceramide plays an important role in the occurrence and development of oral squamous cell carcinoma.However,the function of ceramide synthase 1,a key enzyme in C18 ceramide synthesis,in oral squamous cell carcinoma...C18 ceramide plays an important role in the occurrence and development of oral squamous cell carcinoma.However,the function of ceramide synthase 1,a key enzyme in C18 ceramide synthesis,in oral squamous cell carcinoma is still unclear.The aim of our study was to investigate the relationship between ceramide synthase 1 and oral cancer.In this study,we found that the expression of ceramide synthase 1 was downregulated in oral cancer tissues and cell lines.In a mouse oral squamous cell carcinoma model induced by 4-nitroquinolin-1-oxide,ceramide synthase 1 knockout was associated with the severity of oral malignant transformation.Immunohistochemical studies showed significant upregulation of PCNA,MMP2,MMP9,and BCL2 expression and downregulation of BAX expression in the pathological hyperplastic area.In addition,ceramide synthase 1 knockdown promoted cell proliferation,migration,and invasion in vitro.Overexpression of CERS1 obtained the opposite effect.Ceramide synthase 1 knockdown caused endoplasmic reticulum stress and induced the VEGFA upregulation.Activating transcription factor 4 is responsible for ceramide synthase 1 knockdown caused VEGFA transcriptional upregulation.In addition,mild endoplasmic reticulum stress caused by ceramide synthase 1 knockdown could induce cisplatin resistance.Taken together,our study suggests that ceramide synthase 1 is downregulated in oral cancer and promotes the aggressiveness of oral squamous cell carcinoma and chemotherapeutic drug resistance.展开更多
Flow shop scheduling problem with time lags is a practical scheduling problem and attracts many studies. Permutation problem(PFSP with time lags) is concentrated but non-permutation problem(non-PFSP with time lags...Flow shop scheduling problem with time lags is a practical scheduling problem and attracts many studies. Permutation problem(PFSP with time lags) is concentrated but non-permutation problem(non-PFSP with time lags) seems to be neglected. With the aim to minimize the makespan and satisfy time lag constraints, efficient algo- rithms corresponding to PFSP and non-PFSP problems are proposed, which consist of iterated greedy algorithm for permutation(IGTLP) and iterated greedy algorithm for non-permutation (IGTLNP). The proposed algorithms are verified using well-known simple and complex instances of permutation and non-permutation problems with various time lag ranges. The permutation results indicate that the proposed IGTLP can reach near optimal solution within nearly 11% computational time of traditional GA approach. The non-permutation results indicate that the proposed IG can reach nearly same solution within less than 1% com- putational time compared with traditional GA approach. The proposed research combines PFSP and non-PFSP together with minimal and maximal time lag consideration, which provides an interesting viewpoint for industrial implementation.展开更多
Rheological properties are the theoretical basis and the key to common problems in ferrofluid applications,therefore they are expected to be adjustable to satisfy different technical requirements through altering the ...Rheological properties are the theoretical basis and the key to common problems in ferrofluid applications,therefore they are expected to be adjustable to satisfy different technical requirements through altering the microstructure of ferrofluid during the process of preparation.In this paper,Four ferrofluid samples with different magnetic particle size were prepared by controlling the concentration of precursor solution during co-precipitation process and the rheological properties of these samples were investigated.These samples exhibited field-controlled rheological properties.Eternal magnetic field would enhance the formation of microstructures,resulting in an increase of viscosity.While with the increase of shear rate,microstructures tended to be destroyed,causing viscosity to decrease.There were two opposing mechanisms of the influence of precursor solution concentration.On one hand,the reduction of the precursor solution concentration would produce primary magnetic particles of smaller size.But on the other hand,the surfactant became insufficient to completely coat the magnetic particles because of an increased specific surface area,causing the magnetic particles to aggregate and form secondary clustering structures which strongly enhanced the magnetoviscous effect and weakened the viscoelastic effect.展开更多
Microcystis species identification is essential for ecological studies and water bloom control.Immunoassays are more specific and convenient and several approaches have been used to develop for diagnosing harmful red ...Microcystis species identification is essential for ecological studies and water bloom control.Immunoassays are more specific and convenient and several approaches have been used to develop for diagnosing harmful red tide algae.Howeve r,inve stigations onMicrocystis identification using immunological approaches are still in the initial stage.In this study.Microcystis aeruginosa PCC7806 lysates were utilized as coated antigens to enrich and screen specific Microcystis nanobodies from a human domain antibody display library.After three rounds of enrichment,10 positive monoclonal particles were isolated from the library and the most two positive nanobodies(DAb2 and Dab3)were effectively produced in Escherichia coli BL21.Finally,the DAb2 showed specific immune binding to different Microcystis by the immuno-dot blot assay.This antibody could be used to establish an immunological method to identify Microcystis.展开更多
This paper presents an improved finite control set model predictive current control(FCS-MPCC)of a five-phase permanent magnet synchronous motor(PMSM).First,to avoid including all the 32 voltage vectors provided by a t...This paper presents an improved finite control set model predictive current control(FCS-MPCC)of a five-phase permanent magnet synchronous motor(PMSM).First,to avoid including all the 32 voltage vectors provided by a two-level five-phase inverter into the control set,virtual voltage vectors are adopted.As the third current harmonics can be much reduced by virtual voltage vectors automatically,the harmonic items in the cost function of conventional FCS-MPCC are not considered.Furthermore,an adaptive control set is proposed based on voltage prediction.Best control set with proper voltage vector amplitude corresponding to different rotor speed can be achieved by this method.Consequently,current ripples can be largely reduced and the system performs much better.At last,simulations are established to verify the steady and transient performance of the proposed FCS-MPCC,and experiments based on a 2 kW five-phase motor are carried out.The results have validated the performance improvement of the proposed control strategy.展开更多
To understand the research status of asphalt pavement texture,the related achievements and progress of pavement surface texture were systematically sorted out from three aspects:the characterization of pavement surfac...To understand the research status of asphalt pavement texture,the related achievements and progress of pavement surface texture were systematically sorted out from three aspects:the characterization of pavement surface texture,the texture measurement and evaluation,and the relationship between texture and the skid resistance.Based on the statistical geometric characteristics,the spectral characteristics,the fractal characteristics and the multifractal characteristics,the characteristics of pavement texture were discussed.The test methods of pavement texture were divided into two categories:direct measurement methods and indirect measurement methods.The advantages and disadvantages of each measurement method were summarized.The effects of macro-texture and micro-texture on asphalt pavement were discussed,respectively.The relationship between texture and skid resistance was studied.This review shows that multifractal theory should be further studied from the aspect of road engineering.High-precision non-contact integrated detection technology should be further studied to meet the needs of complex testing environments.The method of finite element numerical simulation has potential for the analysis of pavement skid resistance.In addition,methods such as big data analysis,neural network,and deep learning should be studied to achieve the intelligent perception and management of the whole state of skid resistance prediction.展开更多
High-order harmonics and attosecond pulse generation with coherent wake emission are theoretically investigated for the effect of pulse duration and carrier envelope phase(CEP)of few-cycle laser pulse.We find that sho...High-order harmonics and attosecond pulse generation with coherent wake emission are theoretically investigated for the effect of pulse duration and carrier envelope phase(CEP)of few-cycle laser pulse.We find that short pulse duration will cause the negative chirp for the high harmonics.When the laser pulse is shortened to a few cycles,the influence of the laser CEP on the chirp of the harmonics will also become more prominent.展开更多
The Tibetan Plateau(TP),widely known as the Third Pole,is the highest and largest plateau on Earth.The TP not only plays an important role in influencing the atmospheric circulation,surface energy budget,ecology,weath...The Tibetan Plateau(TP),widely known as the Third Pole,is the highest and largest plateau on Earth.The TP not only plays an important role in influencing the atmospheric circulation,surface energy budget,ecology,weather,and climate but also acts as the Asian Water Tower by holding the largest ice mass outside the polar regions to supply fresh water to over 1.4 billion people downstream in Asia(Qin et al.,2006).The observed historical warming and projected future warming over the TP are much stronger than the corresponding global average(Wang et al.,2008).Glaciers on the TP have been retreating extensively in recent decades,driven by atmospheric warming and circulation changes associated with increasing concentrations of greenhouse gases and aerosols in the atmosphere,light-absorbing particles(e.g.,black carbon,dust)on snow,and other factors(Duan et al.,2012;Qian et al.,2011;Zhao et al.,2020).In addition,due to the thermal and dynam-ical effects of the TP,as well as its proximity to the stratosphere,unique atmospheric boundary layer structures often develop over the TP and in the surrounding areas,which have important impacts on local weather,climate,and mixing and transport of atmospheric constituents(Zhao et al.,2020).The TP is considered a natural laboratory to study multi-sphere inter-actions.A systematic mechanistic understanding of the atmospheric chemical and microphysical processes,climate change,cryospheric variability,and the subsequent environmental impacts is particularly important in the context of the unpreceden-ted warming over the TP(Yao et al.,2019).展开更多
Objective:The objective of this study was to verify the lipid-lowering effect of Juhe Fang extract(JHFE)and to determine its characteristic chemical profile in vitro and in vivo.Methods:A hyperlipidemia model was esta...Objective:The objective of this study was to verify the lipid-lowering effect of Juhe Fang extract(JHFE)and to determine its characteristic chemical profile in vitro and in vivo.Methods:A hyperlipidemia model was established by feeding mice a high-fat diet(HFD).After treatment for 30 days,serum total cholesterol(TC),triglyceride(TG),high-density lipoprotein cholesterol(HDL-C)and low-density lipoprotein cholesterol(LDL-C)levels were measured with an automatic biochemistry analyzer.The components from JHFE obtained from in vivo and in vitro experiments were investigated using an UPLC-Q Exactive-Orbitrap MS/MS.Results:The TC,TG,and LDL-C in the serum significantly decreased and the HDL-C significantly increased after JHFE treatment.A total of 95 compounds from JHEF including 15 phenolic acids(PA),4 phenylethanoid glycosides(PG),24 flavonoids(F),14 triterpenoids(T),10 diterpenoid glycosides(D),18 alkaloids(A)and 10 others(O)were identified.Trigonelline was discovered for the first time in a herbal medicine of Juhe Fang.Furthermore,68 compounds were identified in vivo including 28 prototype compounds and 40 metabolites.The metabolic characteristics of these components were revealed including identification of new metabolites of 4-hydroxyphenyl ethyl-8-O-[a-L-arabinopyranosyl-(1/6)]-b-D-glucopyranoside(PEG)and lirinidine.A total of 43 components from JHFE were absorbed and/or metabolized.The contribution rate of each type of chemical component from JHFE to its lipidlowering effect from high to low were A,F,PG,PA,D and T.Conclusion:The results of this study showed that JHFE demonstrated a significant lipid-lowering effect in a high-fat diet(HFD)-induced hyperlipidemia mouse model.Specific types of PA,PG,F,D,T and A formed the pharmaceutical architecture of the lipid-lowering effect of JHFE.This study should prove useful for clarifying the components responsible for the lipid-lowering effect of JHFE and provide a basis for precision quality control research.展开更多
With the development of natural language processing,deep learning,and other technologies,text steganography is rapidly developing.However,adversarial attack methods have emerged that gives text steganography the abili...With the development of natural language processing,deep learning,and other technologies,text steganography is rapidly developing.However,adversarial attack methods have emerged that gives text steganography the ability to actively spoof steganalysis.If terrorists use the text steganography method to spread terrorist messages,it will greatly disturb social stability.Steganalysis methods,especially those for resisting adversarial attacks,need to be further improved.In this paper,we propose a two-stage highly robust model for text steganalysis.The proposed method analyzes and extracts anomalous features at both intra-sentential and inter-sentential levels.In the first phase,every sentence is first transformed into word vectors.To obtain a high dimensional sentence vector,we use Bi-LSTM to obtain feature information for all words in the sentence while retaining strong correlations.In the second phase,we input multiple sentences vectors into the GNN,from which we extract inter-sentential anomaly features and make a judgment as to whether the text contains secret messages.In addition,to improve the robustness of the model,we add adversarial examples to the training set to improve the robustness and generalization of the steganalysis model.Theoretically,our proposed method is more robust and more accurate in detection compared to existing methods.展开更多
Many rubber friction theories or some method combined theories and field-experiments are employed to evaluate the pavement skid-resistance deterioration due to the evolution of surface textures.However,these methods a...Many rubber friction theories or some method combined theories and field-experiments are employed to evaluate the pavement skid-resistance deterioration due to the evolution of surface textures.However,these methods are difficult to be implemented in the analysis of situations with multi-factor coupling and some extreme conditions.This study developed a framework to evaluate the skid-resistance deterioration of asphalt pavements.In this framework,the portable laser scanning was used to create the digital worn pavement model,and a hydroplaning finite element(FE)model for these digital worn pavements was constructed to evaluate coupling effects of the texture evolution and factors of slip ratio,slip angle,velocity and water film on braking-cornering characteristics of tire.In this study,the deterioration of skid-resistance of five typical asphalt pavements due the surface texture wear was systematically investigated by this framework.Compared with previous works,this study established the rubber friction models for each digital worn pavement considering the energy hysteresis of rubber and the power spectrum density of surface texture.And the rubber friction model was used to define the interaction behaviors between the tire and corresponding wore pavements in the FE hydroplaning model,rather than using an empirical friction model or a fixed friction coefficient.展开更多
As a four-electron transfer reaction,oxygen evolution reaction(OER)is limited by large overpotential and slow kinetics.Here,we in-situ synthesized two-dimensional(2D)Ni-Fe metal-organic framework nanosheets on nickel ...As a four-electron transfer reaction,oxygen evolution reaction(OER)is limited by large overpotential and slow kinetics.Here,we in-situ synthesized two-dimensional(2D)Ni-Fe metal-organic framework nanosheets on nickel foam(NixFe-TPA/NF,TPA=terephthalic acid)for oxygen evolution in alkaline and alkaline seawater electrolytes.In 1 M KOH,Ni3Fe-TPA/NF shows a low overpotential(η10)of 189 mV at 10 mA·cm^(-2) and an ultra-low overpotential of only 260 mV at 500 mA·cm^(-2).In alkaline seawater,Ni3Fe-TPA/NF still provides impressive OER performance,with anη10 of 265 mV.In-situ Raman characterization results show that the phase transition occurs during the OER,and Ni3FeOOH with more oxygen vacancies is in-situ formed,reducing the OER energy barrier.Density functional theory(DFT)reveals that the synergy between Ni and Fe reduces the energy barrier and accelerates the rate-determining step.In addition,the ultra-thin 2D sheet structure and the close combination of Ni3FeOOH and highly conductive NF support ensure the high catalytic OER activity.Therefore,the surface reconstruction and structural modification strategy can be used to design and prepare high-performance OER electrocatalysts for energy-related applications.展开更多
Coronavirus disease 2019(COvID-19)is a severe global public health emergency that has caused a major cri-sis in the safety of human life,health,global economy,and social order.Moreover,CovID-19 poses significant chall...Coronavirus disease 2019(COvID-19)is a severe global public health emergency that has caused a major cri-sis in the safety of human life,health,global economy,and social order.Moreover,CovID-19 poses significant challenges to healthcare systems worldwide.The prediction and early warning of infectious diseases on a global scale are the premise and basis for countries to jointly fight epidemics.However,because of the complexity of epidemics,predicting infectious diseases on a global scale faces significant challenges.In this study,we developed the second version of Global Prediction System for Epidemiological Pandemic(GPEP-2),which combines statis-tical methods with a modified epidemiological model.The GPEP-2 introduces various parameterization schemes for both impacts of natural factors(seasonal variations in weather and environmental impacts)and human so-cial behaviors(government control and isolation,personnel gathered,indoor propagation,virus mutation,and vaccination).The GPEP-2 successfully predicted the COVID-19 pandemic in over 180 countries with an average accuracy rate of 82.7%.It also provided prediction and decision-making bases for several regional-scale CovID-19 pandemic outbreaks in China,with an average accuracy rate of 89.3%.Results showed that both anthropogenic and natural factors can affect virus spread and control measures in the early stages of an epidemic can effectively control the spread.The predicted results could serve as a reference for public health planning and policymaking.展开更多
基金funded by the Hong Kong Research Grants Council(25201620/C6001-22Y)the Hong Kong Innovation Technology Commission(ITC)under project No.MHP/060/21support of the State Key Laboratory of Advanced Displays and Optoelectronics Technologies at HKUST.
文摘Electronic waste(e-waste)and diabetes are global challenges to modern societies.However,solving these two challenges together has been challenging until now.Herein,we propose a laser-induced transfer method to fabricate portable glucose sensors by recycling copper from e-waste.We bring up a laser-induced full-automatic fabrication method for synthesizing continuous heterogeneous Cu_(x)O(h-Cu_(x)O)nano-skeletons electrode for glucose sensing,offering rapid(<1 min),clean,air-compatible,and continuous fabrication,applicable to a wide range of Cu-containing substrates.Leveraging this approach,h-Cu_(x)O nanoskeletons,with an inner core predominantly composed of Cu_(2)O with lower oxygen content,juxtaposed with an outer layer rich in amorphous Cu_(x)O(a-Cu_(x)O)with higher oxygen content,are derived from discarded printed circuit boards.When employed in glucose detection,the h-Cu_(x)O nano-skeletons undergo a structural evolution process,transitioning into rigid Cu_(2)O@CuO nano-skeletons prompted by electrochemical activation.This transformation yields exceptional glucose-sensing performance(sensitivity:9.893 mA mM^(-1) cm^(-2);detection limit:0.34μM),outperforming most previously reported glucose sensors.Density functional theory analysis elucidates that the heterogeneous structure facilitates gluconolactone desorption.This glucose detection device has also been downsized to optimize its scalability and portability for convenient integration into people’s everyday lives.
基金supported by the National Natural Science Foundation of China the National Natural Science Foundation of China(Grant No.41991231)the Fundamental Research Funds for the Central Universities(lzujbky-2022-kb11).
文摘Due to the considerable uncertainties inherent in the datasets describing the spatiotemporal distributions of precipitation in the drylands of China,this study presents a new merged monthly precipitation product with a spatial resolution of approximately 0.2°×0.2°during 1980–2019.The newly developed precipitation product was validated at different temporal scales(e.g.,monthly,seasonally,and annually).The results show that the new product consistently aligns with the spatiotemporal distributions reported by the Chinese Meteorological Administration Land Data Assimilation System(CLDAS)product and Multi-Source Weighted Ensemble Precipitation(MSWEP).The merged product exhibits exceptional quality in describing the drylands of China,with a bias of–2.19 mm month^(–1)relative to MSWEP.In addition,the annual trend of the merged product(0.09 mm month^(–1)yr^(−1))also closely aligns with that of the MSWEP(0.11 mm month^(–1)yr^(−1))during 1980–2019.The increasing trend indicates that the water cycle and wetting process intensified in the drylands of China during this period.In particular,there was an increase in wetting during the period from 2001–2019.Generally,the merged product exhibits potential value for improving our understanding of the climate and water cycle in the drylands of China.
基金This work was jointly supported by a project supported by the Joint Fund of the National Natural Science Foundation of China and the China Meteorological Administration(Grant No.U2242209)the National Natural Science Foundation of China(Grant No.42175106).
文摘Dust storms are one of the most frequent meteorological disasters in China,endangering agricultural production,transportation,air quality,and the safety of people’s lives and property.Against the backdrop of climate change,Mongolia’s contribution to China’s dust cannot be ignored in recent years.In this study,we used the Weather Research and Forecasting model coupled with Chemistry(WRF-Chem),along with dynamic dust sources and the HYSPLIT model,to analyze the contributions of different dust sources to dust concentrations in northern China in March and April 2023.The results show that the frequency of dust storms in 2023 was the highest observed in the past decade.Mongolia and the Taklimakan Desert were identified as two main dust sources contributing to northern China.Specifically,Mongolia contributed more than 42%of dust,while the Taklimakan Desert accounted for 26%.A cold high-pressure center,a cold front,and a Mongolian cyclone resulted in the transport of dust aerosols from Mongolia and the Taklimakan Desert to northern China,where they affected most parts of the region.Moreover,two machine learning methods[the XGBoost algorithm and the Synthetic Minority Oversampling Technique(SMOTE)]were used to forecast the dust storms in March 2023,based on ground observations and WRF-Chem simulations over East Asia.XGBoost-SMOTE performed well in predicting hourly PM10 concentrations in China in March 2023,with a mean absolute error of 33.8μg m−3 and RMSE of 54.2μg m−3.
基金the Artificial Intelligence Key Laboratory of Sichuan Province(Nos.2019RYJ05)National Natural Science Foundation of China(Nos.61971107).
文摘Unmanned Aerial Vehicle(UAV)has emerged as a promising technology for the support of human activities,such as target tracking,disaster rescue,and surveillance.However,these tasks require a large computation load of image or video processing,which imposes enormous pressure on the UAV computation platform.To solve this issue,in this work,we propose an intelligent Task Offloading Algorithm(iTOA)for UAV edge computing network.Compared with existing methods,iTOA is able to perceive the network’s environment intelligently to decide the offloading action based on deep Monte Calor Tree Search(MCTS),the core algorithm of Alpha Go.MCTS will simulate the offloading decision trajectories to acquire the best decision by maximizing the reward,such as lowest latency or power consumption.To accelerate the search convergence of MCTS,we also proposed a splitting Deep Neural Network(sDNN)to supply the prior probability for MCTS.The sDNN is trained by a self-supervised learning manager.Here,the training data set is obtained from iTOA itself as its own teacher.Compared with game theory and greedy search-based methods,the proposed iTOA improves service latency performance by 33%and 60%,respectively.
基金supported by National Natural Science Foundation of China[81972538].
文摘C18 ceramide plays an important role in the occurrence and development of oral squamous cell carcinoma.However,the function of ceramide synthase 1,a key enzyme in C18 ceramide synthesis,in oral squamous cell carcinoma is still unclear.The aim of our study was to investigate the relationship between ceramide synthase 1 and oral cancer.In this study,we found that the expression of ceramide synthase 1 was downregulated in oral cancer tissues and cell lines.In a mouse oral squamous cell carcinoma model induced by 4-nitroquinolin-1-oxide,ceramide synthase 1 knockout was associated with the severity of oral malignant transformation.Immunohistochemical studies showed significant upregulation of PCNA,MMP2,MMP9,and BCL2 expression and downregulation of BAX expression in the pathological hyperplastic area.In addition,ceramide synthase 1 knockdown promoted cell proliferation,migration,and invasion in vitro.Overexpression of CERS1 obtained the opposite effect.Ceramide synthase 1 knockdown caused endoplasmic reticulum stress and induced the VEGFA upregulation.Activating transcription factor 4 is responsible for ceramide synthase 1 knockdown caused VEGFA transcriptional upregulation.In addition,mild endoplasmic reticulum stress caused by ceramide synthase 1 knockdown could induce cisplatin resistance.Taken together,our study suggests that ceramide synthase 1 is downregulated in oral cancer and promotes the aggressiveness of oral squamous cell carcinoma and chemotherapeutic drug resistance.
基金Supported by National Natural Science Foundation of China(Grant No.71301008)Beijing Municipal Natural Science Foundation of China(Grant No.9144030)
文摘Flow shop scheduling problem with time lags is a practical scheduling problem and attracts many studies. Permutation problem(PFSP with time lags) is concentrated but non-permutation problem(non-PFSP with time lags) seems to be neglected. With the aim to minimize the makespan and satisfy time lag constraints, efficient algo- rithms corresponding to PFSP and non-PFSP problems are proposed, which consist of iterated greedy algorithm for permutation(IGTLP) and iterated greedy algorithm for non-permutation (IGTLNP). The proposed algorithms are verified using well-known simple and complex instances of permutation and non-permutation problems with various time lag ranges. The permutation results indicate that the proposed IGTLP can reach near optimal solution within nearly 11% computational time of traditional GA approach. The non-permutation results indicate that the proposed IG can reach nearly same solution within less than 1% com- putational time compared with traditional GA approach. The proposed research combines PFSP and non-PFSP together with minimal and maximal time lag consideration, which provides an interesting viewpoint for industrial implementation.
基金National Natural Science Foundation of China(Grant Nos.51927810,51735006,U1837206)Beijing Municipal Natural Science Foundation of China(Grant No.3182013).
文摘Rheological properties are the theoretical basis and the key to common problems in ferrofluid applications,therefore they are expected to be adjustable to satisfy different technical requirements through altering the microstructure of ferrofluid during the process of preparation.In this paper,Four ferrofluid samples with different magnetic particle size were prepared by controlling the concentration of precursor solution during co-precipitation process and the rheological properties of these samples were investigated.These samples exhibited field-controlled rheological properties.Eternal magnetic field would enhance the formation of microstructures,resulting in an increase of viscosity.While with the increase of shear rate,microstructures tended to be destroyed,causing viscosity to decrease.There were two opposing mechanisms of the influence of precursor solution concentration.On one hand,the reduction of the precursor solution concentration would produce primary magnetic particles of smaller size.But on the other hand,the surfactant became insufficient to completely coat the magnetic particles because of an increased specific surface area,causing the magnetic particles to aggregate and form secondary clustering structures which strongly enhanced the magnetoviscous effect and weakened the viscoelastic effect.
基金Supported by the National Natural Science Foundation of China(Nos.31971561,31370217,31701724)the Research Program of Jiangsu Province of China。
文摘Microcystis species identification is essential for ecological studies and water bloom control.Immunoassays are more specific and convenient and several approaches have been used to develop for diagnosing harmful red tide algae.Howeve r,inve stigations onMicrocystis identification using immunological approaches are still in the initial stage.In this study.Microcystis aeruginosa PCC7806 lysates were utilized as coated antigens to enrich and screen specific Microcystis nanobodies from a human domain antibody display library.After three rounds of enrichment,10 positive monoclonal particles were isolated from the library and the most two positive nanobodies(DAb2 and Dab3)were effectively produced in Escherichia coli BL21.Finally,the DAb2 showed specific immune binding to different Microcystis by the immuno-dot blot assay.This antibody could be used to establish an immunological method to identify Microcystis.
基金This work was supported in part by the National Natural Science Foundation of China under 61374125。
文摘This paper presents an improved finite control set model predictive current control(FCS-MPCC)of a five-phase permanent magnet synchronous motor(PMSM).First,to avoid including all the 32 voltage vectors provided by a two-level five-phase inverter into the control set,virtual voltage vectors are adopted.As the third current harmonics can be much reduced by virtual voltage vectors automatically,the harmonic items in the cost function of conventional FCS-MPCC are not considered.Furthermore,an adaptive control set is proposed based on voltage prediction.Best control set with proper voltage vector amplitude corresponding to different rotor speed can be achieved by this method.Consequently,current ripples can be largely reduced and the system performs much better.At last,simulations are established to verify the steady and transient performance of the proposed FCS-MPCC,and experiments based on a 2 kW five-phase motor are carried out.The results have validated the performance improvement of the proposed control strategy.
基金This paper is part of the research work of National Key R&D Project of China(Grant No.2021YFB2600601,2021YFB2600605,2021YFB 2600600)The authors would like to acknowledge the financial support provided by the National Natural Science Foundation of China(Grant No.51922030)“the Fundamental Research Funds for the Central Universities”(Grant No.2242022R10019).
文摘To understand the research status of asphalt pavement texture,the related achievements and progress of pavement surface texture were systematically sorted out from three aspects:the characterization of pavement surface texture,the texture measurement and evaluation,and the relationship between texture and the skid resistance.Based on the statistical geometric characteristics,the spectral characteristics,the fractal characteristics and the multifractal characteristics,the characteristics of pavement texture were discussed.The test methods of pavement texture were divided into two categories:direct measurement methods and indirect measurement methods.The advantages and disadvantages of each measurement method were summarized.The effects of macro-texture and micro-texture on asphalt pavement were discussed,respectively.The relationship between texture and skid resistance was studied.This review shows that multifractal theory should be further studied from the aspect of road engineering.High-precision non-contact integrated detection technology should be further studied to meet the needs of complex testing environments.The method of finite element numerical simulation has potential for the analysis of pavement skid resistance.In addition,methods such as big data analysis,neural network,and deep learning should be studied to achieve the intelligent perception and management of the whole state of skid resistance prediction.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.91950203,11874374,and 61690223)the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB16).
文摘High-order harmonics and attosecond pulse generation with coherent wake emission are theoretically investigated for the effect of pulse duration and carrier envelope phase(CEP)of few-cycle laser pulse.We find that short pulse duration will cause the negative chirp for the high harmonics.When the laser pulse is shortened to a few cycles,the influence of the laser CEP on the chirp of the harmonics will also become more prominent.
基金supported by the US Department of Energy Office of Science Biological and Environmental Research as part of the Regional and Global Model Analysis program areasupported by the National Natural Science Foundation of China NSFC (Grant Nos.91837310,42061134009,41775146)+1 种基金the USTC Research Funds of the Double First-Class Initiative(YD2080002007)supported by the Second Tibetan Plateau Scientific Expedition and Research program (Grant No.2019QZKK0605)
文摘The Tibetan Plateau(TP),widely known as the Third Pole,is the highest and largest plateau on Earth.The TP not only plays an important role in influencing the atmospheric circulation,surface energy budget,ecology,weather,and climate but also acts as the Asian Water Tower by holding the largest ice mass outside the polar regions to supply fresh water to over 1.4 billion people downstream in Asia(Qin et al.,2006).The observed historical warming and projected future warming over the TP are much stronger than the corresponding global average(Wang et al.,2008).Glaciers on the TP have been retreating extensively in recent decades,driven by atmospheric warming and circulation changes associated with increasing concentrations of greenhouse gases and aerosols in the atmosphere,light-absorbing particles(e.g.,black carbon,dust)on snow,and other factors(Duan et al.,2012;Qian et al.,2011;Zhao et al.,2020).In addition,due to the thermal and dynam-ical effects of the TP,as well as its proximity to the stratosphere,unique atmospheric boundary layer structures often develop over the TP and in the surrounding areas,which have important impacts on local weather,climate,and mixing and transport of atmospheric constituents(Zhao et al.,2020).The TP is considered a natural laboratory to study multi-sphere inter-actions.A systematic mechanistic understanding of the atmospheric chemical and microphysical processes,climate change,cryospheric variability,and the subsequent environmental impacts is particularly important in the context of the unpreceden-ted warming over the TP(Yao et al.,2019).
基金the innovative research team of the Twelfth Five-Year National Science and Technology Support Program(Grant no.2012BAI29B06)the Beijing University of Chinese Medicine of China(Grant no.2011-CXTD-12).
文摘Objective:The objective of this study was to verify the lipid-lowering effect of Juhe Fang extract(JHFE)and to determine its characteristic chemical profile in vitro and in vivo.Methods:A hyperlipidemia model was established by feeding mice a high-fat diet(HFD).After treatment for 30 days,serum total cholesterol(TC),triglyceride(TG),high-density lipoprotein cholesterol(HDL-C)and low-density lipoprotein cholesterol(LDL-C)levels were measured with an automatic biochemistry analyzer.The components from JHFE obtained from in vivo and in vitro experiments were investigated using an UPLC-Q Exactive-Orbitrap MS/MS.Results:The TC,TG,and LDL-C in the serum significantly decreased and the HDL-C significantly increased after JHFE treatment.A total of 95 compounds from JHEF including 15 phenolic acids(PA),4 phenylethanoid glycosides(PG),24 flavonoids(F),14 triterpenoids(T),10 diterpenoid glycosides(D),18 alkaloids(A)and 10 others(O)were identified.Trigonelline was discovered for the first time in a herbal medicine of Juhe Fang.Furthermore,68 compounds were identified in vivo including 28 prototype compounds and 40 metabolites.The metabolic characteristics of these components were revealed including identification of new metabolites of 4-hydroxyphenyl ethyl-8-O-[a-L-arabinopyranosyl-(1/6)]-b-D-glucopyranoside(PEG)and lirinidine.A total of 43 components from JHFE were absorbed and/or metabolized.The contribution rate of each type of chemical component from JHFE to its lipidlowering effect from high to low were A,F,PG,PA,D and T.Conclusion:The results of this study showed that JHFE demonstrated a significant lipid-lowering effect in a high-fat diet(HFD)-induced hyperlipidemia mouse model.Specific types of PA,PG,F,D,T and A formed the pharmaceutical architecture of the lipid-lowering effect of JHFE.This study should prove useful for clarifying the components responsible for the lipid-lowering effect of JHFE and provide a basis for precision quality control research.
基金This work is supported by the National Natural Science Foundation of China under Grant U1836110,U1836208by the Jiangsu Basic Research Programs-Natural Science Foundation under grant numbers BK20200039+3 种基金by China Postdoctoral Science Foundation(2017M610574)by the Collaborative Innovation Center of Atmospheric Environment and Equipment Technology(CICAEET)fund,Chinaby the Opening Project of Guangxi Key Laboratory of Cryptography and Information Security(No.GCIS201713)Guangdong Provincial Key Laboratory of Data Security and Privacy Protection(Grant No.2017B03031004)。
文摘With the development of natural language processing,deep learning,and other technologies,text steganography is rapidly developing.However,adversarial attack methods have emerged that gives text steganography the ability to actively spoof steganalysis.If terrorists use the text steganography method to spread terrorist messages,it will greatly disturb social stability.Steganalysis methods,especially those for resisting adversarial attacks,need to be further improved.In this paper,we propose a two-stage highly robust model for text steganalysis.The proposed method analyzes and extracts anomalous features at both intra-sentential and inter-sentential levels.In the first phase,every sentence is first transformed into word vectors.To obtain a high dimensional sentence vector,we use Bi-LSTM to obtain feature information for all words in the sentence while retaining strong correlations.In the second phase,we input multiple sentences vectors into the GNN,from which we extract inter-sentential anomaly features and make a judgment as to whether the text contains secret messages.In addition,to improve the robustness of the model,we add adversarial examples to the training set to improve the robustness and generalization of the steganalysis model.Theoretically,our proposed method is more robust and more accurate in detection compared to existing methods.
基金National Key R&D Program of China(Grant Nos.2021YFB2600601 and 2021YFB2600600)support provided by the Opening Funding Supported by the Key Laboratory of Transport Industry of Road Structure and Material(Research Institute of Highway Ministry of Transport),Beijing,China,the National Natural Science Foundation of China(Grant No.52278444)Postgraduate Research&Practice Innovation of Jiangsu Province(Grant No.KYCX22_0275).
文摘Many rubber friction theories or some method combined theories and field-experiments are employed to evaluate the pavement skid-resistance deterioration due to the evolution of surface textures.However,these methods are difficult to be implemented in the analysis of situations with multi-factor coupling and some extreme conditions.This study developed a framework to evaluate the skid-resistance deterioration of asphalt pavements.In this framework,the portable laser scanning was used to create the digital worn pavement model,and a hydroplaning finite element(FE)model for these digital worn pavements was constructed to evaluate coupling effects of the texture evolution and factors of slip ratio,slip angle,velocity and water film on braking-cornering characteristics of tire.In this study,the deterioration of skid-resistance of five typical asphalt pavements due the surface texture wear was systematically investigated by this framework.Compared with previous works,this study established the rubber friction models for each digital worn pavement considering the energy hysteresis of rubber and the power spectrum density of surface texture.And the rubber friction model was used to define the interaction behaviors between the tire and corresponding wore pavements in the FE hydroplaning model,rather than using an empirical friction model or a fixed friction coefficient.
基金supported by the National Natural Science Foundation of China(No.22075099)the Natural Science Foundation of Jilin Province(Nos.20220101051JC and 20200201395JC)the Education Department of Jilin Province(Nos.JJKH20220967KJ and JJKH20220968CY).
文摘As a four-electron transfer reaction,oxygen evolution reaction(OER)is limited by large overpotential and slow kinetics.Here,we in-situ synthesized two-dimensional(2D)Ni-Fe metal-organic framework nanosheets on nickel foam(NixFe-TPA/NF,TPA=terephthalic acid)for oxygen evolution in alkaline and alkaline seawater electrolytes.In 1 M KOH,Ni3Fe-TPA/NF shows a low overpotential(η10)of 189 mV at 10 mA·cm^(-2) and an ultra-low overpotential of only 260 mV at 500 mA·cm^(-2).In alkaline seawater,Ni3Fe-TPA/NF still provides impressive OER performance,with anη10 of 265 mV.In-situ Raman characterization results show that the phase transition occurs during the OER,and Ni3FeOOH with more oxygen vacancies is in-situ formed,reducing the OER energy barrier.Density functional theory(DFT)reveals that the synergy between Ni and Fe reduces the energy barrier and accelerates the rate-determining step.In addition,the ultra-thin 2D sheet structure and the close combination of Ni3FeOOH and highly conductive NF support ensure the high catalytic OER activity.Therefore,the surface reconstruction and structural modification strategy can be used to design and prepare high-performance OER electrocatalysts for energy-related applications.
基金the Collaborative Research Project of the National Natural Science Foundation of China(L2224041)the Chinese Academy of Sciences(XK2022DXC005)+1 种基金Frontier of Interdisciplinary Research on Monitoring and Prediction of Pathogenic Microorganisms in the Atmosphere,Self-supporting Program of Guangzhou Laboratory(SRPG22–007)Gansu Province Intellectual Property Program(Oriented Organization)Project(22ZSCQD02).
文摘Coronavirus disease 2019(COvID-19)is a severe global public health emergency that has caused a major cri-sis in the safety of human life,health,global economy,and social order.Moreover,CovID-19 poses significant challenges to healthcare systems worldwide.The prediction and early warning of infectious diseases on a global scale are the premise and basis for countries to jointly fight epidemics.However,because of the complexity of epidemics,predicting infectious diseases on a global scale faces significant challenges.In this study,we developed the second version of Global Prediction System for Epidemiological Pandemic(GPEP-2),which combines statis-tical methods with a modified epidemiological model.The GPEP-2 introduces various parameterization schemes for both impacts of natural factors(seasonal variations in weather and environmental impacts)and human so-cial behaviors(government control and isolation,personnel gathered,indoor propagation,virus mutation,and vaccination).The GPEP-2 successfully predicted the COVID-19 pandemic in over 180 countries with an average accuracy rate of 82.7%.It also provided prediction and decision-making bases for several regional-scale CovID-19 pandemic outbreaks in China,with an average accuracy rate of 89.3%.Results showed that both anthropogenic and natural factors can affect virus spread and control measures in the early stages of an epidemic can effectively control the spread.The predicted results could serve as a reference for public health planning and policymaking.