Open caissons are widely used in foundation engineering because of their load-bearing efficiency and adaptability in diverse soil conditions.However,accurately predicting their undrained bearing capacity in layered so...Open caissons are widely used in foundation engineering because of their load-bearing efficiency and adaptability in diverse soil conditions.However,accurately predicting their undrained bearing capacity in layered soils remains a complex challenge.This study presents a novel application of five ensemble machine(ML)algorithms-random forest(RF),gradient boosting machine(GBM),extreme gradient boosting(XGBoost),adaptive boosting(AdaBoost),and categorical boosting(CatBoost)-to predict the undrained bearing capacity factor(Nc)of circular open caissons embedded in two-layered clay on the basis of results from finite element limit analysis(FELA).The input dataset consists of 1188 numerical simulations using the Tresca failure criterion,varying in geometrical and soil parameters.The FELA was performed via OptumG2 software with adaptive meshing techniques and verified against existing benchmark studies.The ML models were trained on 70% of the dataset and tested on the remaining 30%.Their performance was evaluated using six statistical metrics:coefficient of determination(R²),mean absolute error(MAE),root mean squared error(RMSE),index of scatter(IOS),RMSE-to-standard deviation ratio(RSR),and variance explained factor(VAF).The results indicate that all the models achieved high accuracy,with R²values exceeding 97.6%and RMSE values below 0.02.Among them,AdaBoost and CatBoost consistently outperformed the other methods across both the training and testing datasets,demonstrating superior generalizability and robustness.The proposed ML framework offers an efficient,accurate,and data-driven alternative to traditional methods for estimating caisson capacity in stratified soils.This approach can aid in reducing computational costs while improving reliability in the early stages of foundation design.展开更多
Ball milling is an environmentally friendly technology for the remediation of petroleumcontaminated soil(PCS),but the cleanup of organic pollutants requires a long time,and the post-remediation soil needs an economica...Ball milling is an environmentally friendly technology for the remediation of petroleumcontaminated soil(PCS),but the cleanup of organic pollutants requires a long time,and the post-remediation soil needs an economically viable disposal/reuse strategy due to its vast volume.The present paper develops a ball milling process under oxygen atmosphere to enhance PCS remediation and reuse the obtained carbonized soil(BCS-O)as wastewater treatment materials.The total petroleum hydrocarbon removal rates by ball milling under vacuum,air,and oxygen atmospheres are 39.83%,55.21%,and 93.84%,respectively.The Langmuir and pseudo second-order models satisfactorily describe the adsorption capacity and behavior of BCS-O for transition metals.The Cu^(2+),Ni^(2+),and Mn^(2+)adsorbed onto BCS-O were mainly bound to metal carbonates and metal oxides.Furthermore,BCS-O can effectively activate persulfate(PDS)oxidation to degrade aniline,while BCS-O loaded with transition metal(BCS-O-Me)shows better activation efficiency and reusability.BCS-O and BCS-O-Me activated PDS oxidation systems are dominated by^(1)O_(2)oxidation and electron transfer.The main active sites are oxygen-containing functional groups,vacancy defects,and graphitized carbon.The oxygen-containing functional groups and vacancy defects primarily activate PDS to generate^(1)O_(2)and attack aniline.Graphitized carbon promotes aniline degradation by accelerating electron transfer.The paper develops an innovative strategy to simultaneously realize efficient remediation of PCS and sequential reuse of the postremediation soil.展开更多
The Sq(solar quiet)geomagnetic field is generated by the electric currents in the E-region of the ionosphere,driven by the atmospheric tides.It is a critical part of high-precision geomagnetic field modeling.Based on ...The Sq(solar quiet)geomagnetic field is generated by the electric currents in the E-region of the ionosphere,driven by the atmospheric tides.It is a critical part of high-precision geomagnetic field modeling.Based on the classic thermal tide theory and atmospheric electrodynamics,this research,for the first time,developed an Sq geomagnetic field model that is directly built on the physical mechanism of the ionospheric dynamo,which is responsible for daily variations of the geomagnetic field.The performance in Sq geomagnetic field modeling was investigated using the Macao Science Satellite-1(MSS-1)data.Our model can enhance the physics-based framework of comprehensive geomagnetic field modeling for the MSS-1 and ensuing missions.展开更多
To explain the influence mechanism of MgO on the consolidation and reduction characteristics of roasted iron pellets,the properties and structure of pellets were investigated from multi-dimensions.It indicated that th...To explain the influence mechanism of MgO on the consolidation and reduction characteristics of roasted iron pellets,the properties and structure of pellets were investigated from multi-dimensions.It indicated that the MgO addition decreased the reduction swelling index(RSI)and reduction degree of pellets in both CO and H_(2)atmospheres.During the stepwise reduction process of Fe2O3→Fe3O4→FeO,the reduction behaviour of pellets in CO and H_(2)was similar,while the reduction rate of pellets in H_(2)atmosphere was almost twice as high as that in CO atmosphere.During the stepwise reduction process of FeO→Fe,the RSI of pellets showed a logarithmic increase in CO atmosphere and a linear decrease in H_(2)atmosphere.As investigated by first-principles calculations,C and Fe mainly formed chemical bonds,and the CO reduction process released energy,promoting the formation of iron whiskers.However,H and Fe produced weak physical adsorption,and the H_(2)reduction process was endothermic,inhibiting the generation of iron whiskers.With Mg2+doping in FexO,the nucleation region of iron whiskers expanded in CO reduction process,and the morphology of iron whiskers transformed from“slender”to“stocky,”reducing RSI of the pellets.展开更多
This study investigates the effects of radiation force due to the rotational pitch motion of a wave energy device,which comprises a coaxial bottom-mounted cylindrical caisson in a two-layer fluid,along with a submerge...This study investigates the effects of radiation force due to the rotational pitch motion of a wave energy device,which comprises a coaxial bottom-mounted cylindrical caisson in a two-layer fluid,along with a submerged cylindrical buoy.The system is modeled as a two-layer fluid with infinite horizontal extent and finite depth.The radiation problem is analyzed in the context of linear water waves.The fluid domain is divided into outer and inner zones,and mathematical solutions for the pitch radiating potential are derived for the corresponding boundary valve problem in these zones using the separation of variables approach.Using the matching eigenfunction expansion method,the unknown coefficients in the analytical expression of the radiation potentials are evaluated.The resulting radiation potential is then used to compute the added mass and damping coefficients.Several numerical results for the added mass and damping coefficients are investigated for numerous parameters,particularly the effects of the cylinder radius,the draft of the submerged cylinder,and the density proportion between the two fluid layers across different frequency ranges.The major findings are presented and discussed.展开更多
Network Intrusion Detection System(NIDS)detection of minority class attacks is always a difficult task when dealing with attacks in complex network environments.To improve the detection capability of minority-class at...Network Intrusion Detection System(NIDS)detection of minority class attacks is always a difficult task when dealing with attacks in complex network environments.To improve the detection capability of minority-class attacks,this study proposes an intrusion detection method based on a two-layer structure.The first layer employs a CNN-BiLSTM model incorporating an attention mechanism to classify network traffic into normal traffic,majority class attacks,and merged minority class attacks.The second layer further segments the minority class attacks through Stacking ensemble learning.The datasets are selected from the generic network dataset CIC-IDS2017,NSL-KDD,and the industrial network dataset Mississippi Gas Pipeline dataset to enhance the generalization and practical applicability of the model.Experimental results show that the proposed model achieves an overall detection accuracy of 99%,99%,and 95%on the CIC-IDS2017,NSL-KDD,and industrial network datasets,respectively.It also significantly outperforms traditional methods in terms of detection accuracy and recall rate for minority class attacks.Compared with the single-layer deep learning model,the two-layer structure effectively reduces the false alarm rate while improving the minority-class attack detection performance.The research in this paper not only improves the adaptability of NIDS to complex network environments but also provides a new solution for minority-class attack detection in industrial network security.展开更多
BACKGROUND The early diagnosis rate of pancreatic ductal adenocarcinoma(PDAC)is low and the prognosis is poor.It is important to develop an interpretable noninvasive early diagnostic model in clinical practice.AIM To ...BACKGROUND The early diagnosis rate of pancreatic ductal adenocarcinoma(PDAC)is low and the prognosis is poor.It is important to develop an interpretable noninvasive early diagnostic model in clinical practice.AIM To develop an interpretable noninvasive early diagnostic model for PDAC using plasma extracellular vesicle long RNA(EvlRNA).METHODS The diagnostic model was constructed based on plasma EvlRNA data.During the process of establishing the model,EvlRNA-index was introduced,and four algorithms were adopted to calculate EvlRNA-index.After the model was successfully constructed,performance evaluation was conducted.A series of bioinformatics methods were adopted to explore the potential mechanism of EvlRNA-index as the input feature of the model.And the relationship between key characteristics and PDAC were explored at the single-cell level.RESULTS A novel interpretable machine learning framework was developed based on plasma EvlRNA.In this framework,a two-layer classifier was established.A new concept was proposed:EvlRNA-index.Based on EvlRNA-index,a cancer diagnostic model was established,and a good diagnostic effect was achieved.The accuracy of PDACandCPvsHealth-Probabilistic PCA Index-SVM(PDAC and chronic pancreatitis vs health-probabilistic principal component analysis index-support vector machine)(1-18)was 91.51%,with Mathew’s correlation coefficient 0.7760 and area under the curve 0.9560.In the second layer of the model,the accuracy of PDACvsCP-Probabilistic PCA Index-RF(PDAC vs chronic pancreatitis-probabilistic principal component analysis index-random forest)(2-17)was 93.83%,with Mathew’s correlation coefficient 0.8422 and area under the curve 0.9698.Forty-nine PDAC-related genes were identified,among which 16 were known,inferring that the remaining ones were also PDAC-related genes.CONCLUSION An interpretable two-layer machine learning framework was proposed for early diagnosis and prediction of PDAC based on plasma EvlRNA,providing new insights into the clinical value of EvlRNA.展开更多
In the wake of major natural disasters or human-made disasters,the communication infrastruc-ture within disaster-stricken areas is frequently dam-aged.Unmanned aerial vehicles(UAVs),thanks to their merits such as rapi...In the wake of major natural disasters or human-made disasters,the communication infrastruc-ture within disaster-stricken areas is frequently dam-aged.Unmanned aerial vehicles(UAVs),thanks to their merits such as rapid deployment and high mobil-ity,are commonly regarded as an ideal option for con-structing temporary communication networks.Con-sidering the limited computing capability and battery power of UAVs,this paper proposes a two-layer UAV cooperative computing offloading strategy for emer-gency disaster relief scenarios.The multi-agent twin delayed deep deterministic policy gradient(MATD3)algorithm integrated with prioritized experience replay(PER)is utilized to jointly optimize the scheduling strategies of UAVs,task offloading ratios,and their mobility,aiming to diminish the energy consumption and delay of the system to the minimum.In order to address the aforementioned non-convex optimiza-tion issue,a Markov decision process(MDP)has been established.The results of simulation experiments demonstrate that,compared with the other four base-line algorithms,the algorithm introduced in this paper exhibits better convergence performance,verifying its feasibility and efficacy.展开更多
Arsenic(As),classified as a Group I carcinogen by the International Agency for Research on Cancer(IARC),poses severe risks to ecosystems and human health through atmospheric exposure.This review synthesizes current kn...Arsenic(As),classified as a Group I carcinogen by the International Agency for Research on Cancer(IARC),poses severe risks to ecosystems and human health through atmospheric exposure.This review synthesizes current knowledge on the sources,health impacts,and control strategies of atmospheric arsenic,with an emphasis on its global transport and toxicity.Natural sources,such as volcanic eruptions and soil erosion,contribute approximately 2.1 Gg/year;however,anthropogenic activities,notably metal smelting and coal combustion,dominate emissions,with global anthropogenic releases reaching approximately 28.6 Gg/year.Atmospheric arsenic primarily exists in two forms:particulate matter(PM_(2.5)-bound As(Ⅴ)/As(Ⅲ)and methylated species)and gaseous forms(e.g.,AsH_(3),As_(2)O_(3)),facilitating long-range transport and cross-continental pollution,as evidenced by Asian emissions contributing 39% of Arctic deposition.Advanced techniques,such as inductively coupled plasma mass spectrometry(ICP-MS)and models like GEOS-Chem,enhance emission tracking;however,gaps persist in monitoring gaseous arsenic and refining emission inventories.Health risks include lung cancer,neurotoxicity,and cardiovascular diseases,exacerbated by inhalation and dietary exposure via contaminated crops.Control technologies,including calcium-and iron-based adsorbents and industrial scrubbers,show promise but face challenges related to efficiency and cost.Regional strategies,such as China’s tightened emission limits(0.5 mg/m^(3))and the EU’s Best Available Techniques(BAT),highlight progress,yet global cooperation remains vital for transboundary mitigation.Future research should prioritize low-cost sensors,elucidating speciation-toxicity relationships,and AI-driven emission management to address data gaps and optimize policies.Integrating multidisciplinary approaches—advanced science,stringent regulations,and international collaboration—is crucial to mitigate the environmental and public health impacts of arsenic amid growing industrialization and climate change.展开更多
Cement production,while essential for global infrastructure,contributes significantly to carbon dioxide emissions,accounting for approximately 7%of total emissions.To mitigate these environmental impacts,flash calcina...Cement production,while essential for global infrastructure,contributes significantly to carbon dioxide emissions,accounting for approximately 7%of total emissions.To mitigate these environmental impacts,flash calcination of kaolinitic clays has been investigated as a sustainable alternative.This technique involves the rapid heating of clays,enabling their use as supplementary cementitious materials.The primary objective of this study was to modify the color of calcined clay in various atmospheres(oxidizing,inert,and reducing)to achieve a grayish tone similar to commercial cement while preserving its reactive properties.The experimental procedure employed a tubular reactor with precise control of gas flows(atmospheric air,nitrogen,and a carbon monoxide–nitrogen mixture).Physicochemical characterization of the raw clay was conducted before calcination,with analyses repeated on the calcined clays following experimentation.Results indicated that clay calcined in an oxidizing atmosphere acquired a reddish hue,attributed to the oxidation of iron in hematite.The Clay exhibited a pinkish tone in an inert atmosphere,while calcination in a reducing atmosphere yielded the desired grayish color.Regarding pozzolanic activity,clays calcined in oxidizing and inert atmospheres displayed robust strength,ranging from 82%to 87%.Calcination in a reducing atmosphere resulted in slightly lower strength,around 74%,likely due to the clay’s chemical composition and the calcination process,which affects compound formation and material reactivity.展开更多
This study employs Principal Component Analysis(PCA)and 13 years of SD-WACCM-X model data(2007-2019)to investigate the characteristics and mechanisms of Inter-hemispheric Coupling(IHC)triggered by sudden stratospheric...This study employs Principal Component Analysis(PCA)and 13 years of SD-WACCM-X model data(2007-2019)to investigate the characteristics and mechanisms of Inter-hemispheric Coupling(IHC)triggered by sudden stratospheric warming(SSW)events.IHC in both hemispheres leads to a cold anomaly in the equatorial stratosphere,a warm anomaly in the equatorial mesosphere,and increased temperatures in the mesosphere and lower thermosphere(MLT)region of the summer hemisphere.However,the IHC features during boreal winter period are significantly weaker than during the austral winter period,primarily due to weaker stationary planetary wave activity in the Southern Hemisphere(SH).During the austral winter period,IHC results in a warm anomaly in the polar mesosphere of the SH,which does not occur in the NH during boreal winter period.This study also examines the possible influence of quasi-two-day waves(QTDWs)on IHC.We found that the largest temperature anomaly in the summer polar MLT region is associated with a large wind instability area,and a well-developed critical layer structure of QTDW in January.In contrast,during July,despite favorable conditions for QTDW propagation in the Northern Hemisphere,weaker IHC response is observed,suggesting that IHC features and the relationship with QTDWs during July would be more complex than during January.展开更多
The direct deoxygenative homo-coupling of benzyl alcohols holds great promise to build up bibenzyl motifs in organic synthesis,yet it remains a grand challenge in selectivity and activity control.Herein,we first disco...The direct deoxygenative homo-coupling of benzyl alcohols holds great promise to build up bibenzyl motifs in organic synthesis,yet it remains a grand challenge in selectivity and activity control.Herein,we first discovered that iron carbide catalysts displayed high efficiency and selectivity in the catalytic deoxygenative homo-coupling of benzyl alcohols into bibenzyls using H_(2)as the reductant.Ir-promoted Fe0@Fe_(5)C_(2)gave the best performance among the investigated catalysts,and a broad scope of substrates with diverse functional groups could be smoothly converted into bibenzyls,with the yield up to 85%.In addition,in the presence of alkenes,three-component coupling reactions between alcohols and alkenes were also for the first time achieved to construct more complex multi-ring molecules.The radical-trapping experiment and FTIR measurements revealed the radical nature of the reaction and the significantly promoted C–O bond activation after carbonization,respectively.This work will provide guidelines for the rational design of efficient and selective catalysts for the alcohol-involved carbon-carbon coupling reactions.展开更多
Due to the high elevation and cold climate of the Tibetan Plateau,the western region retains extensive snow cover during the summer,which can exhibit rapid variability over the course of just a few days.This study uti...Due to the high elevation and cold climate of the Tibetan Plateau,the western region retains extensive snow cover during the summer,which can exhibit rapid variability over the course of just a few days.This study utilizes numerical experiments to investigate the atmospheric response to extreme Tibetan Plateau snow cover(TPSC)events on a subseasonal timescale during summer.The results indicate that the subseasonal variations in TPSC exert limited impact on nonlocal atmospheric circulation and temperature during this period.Nevertheless,local surface energy and atmospheric temperature exhibit rapid cooling responses to increased snow cover.Specifically,an increase in snow cover over the western Tibetan Plateau leads to a sharp rise in surface albedo,resulting in a reduction in land surface energy and a negative response in the diabatic heating rate from the surface to 350 hPa locally.This negative diabatic heating response subsequently causes a decline in both surface and overlying atmospheric temperatures.The temperature response is confined to the western Tibetan Plateau and extends vertically from the surface to approximately 350 hPa.These extreme TPSC events and their associated atmospheric impacts occur within a two-week timescale.展开更多
Knowing the optimal operating parameters of Stirling engines is important for efficient combustion through adaptability to changed pressures and oxygen atmospheres. In this study, the optimum operating conditions for ...Knowing the optimal operating parameters of Stirling engines is important for efficient combustion through adaptability to changed pressures and oxygen atmospheres. In this study, the optimum operating conditions for efficient combustion in a singular Stirling engine combustor at different oxygen atmospheres were investigated and determined. Numerical simulations were performed to investigate the effects of ejection ratio and pressure on combustion performance. In an oxygen/carbon dioxide atmosphere, the results show that increasing the ejection ratio substantially alters the flame distribution in the Stirling engine combustor, increasing heat transfer and external combustion efficiency. In contrast, increasing the ejection ratio reduces the average and maximum temperatures of the Stirling engine combustor. Increased pressure affects the flame distribution in the Stirling engine combustor and impedes the flow and convective heat transfer in the combustor, reducing the overall external combustion efficiency at pressures above 6.5 MPa. In an air/carbon dioxide atmosphere, an increased ejection ratio reduces the average and maximum temperatures in the Stirling engine combustor. However, the overall flame distribution does not change substantially. The external combustion efficiency tends to increase and then decrease because of two opposing factors: the increase in the convective heat transfer coefficient and the decrease in the temperature difference. Increasing pressure inhibits forced convection heat transfer in the Stirling engine combustor, reducing external combustion efficiency, which drops from 78% to 65% when pressure increases from 0.2 MPa to 0.5 MPa.展开更多
CaBaCo_(4)O_(7)has been widely studied because of its distinctive structure and magnetic properties.This study examined the influence of different cooling atmospheres on the structure,magnetic properties,and dielectri...CaBaCo_(4)O_(7)has been widely studied because of its distinctive structure and magnetic properties.This study examined the influence of different cooling atmospheres on the structure,magnetic properties,and dielectric behavior of CaBaCo_(4)O_(7).Samples were cooled under different atmospheric conditions to assess these influences.Our findings indicate that reduced oxygen content leads to increased lattice distortion.Since oxygen atoms play a crucial role in mediating magnetic exchange,oxygen deficiency disrupts long-range magnetic order and promotes short-range antiferromagnetic interactions.Additionally,the cooling atmosphere significantly impacts grain size,thereby affecting the dielectric constant and dielectric loss.In the argon-cooled CaBaCo_(4)O_(7)(Ar)sample,oxygen deficiency reduced dielectric permittivity and increased dielectric loss.展开更多
The year,2024,marks the 40th anniversary of Chinese research expeditions in the polar regions and the 25th anniversary of its Arctic research expeditions.China has conducted 14 national Arctic research expeditions.Wit...The year,2024,marks the 40th anniversary of Chinese research expeditions in the polar regions and the 25th anniversary of its Arctic research expeditions.China has conducted 14 national Arctic research expeditions.With the increase of understandings on the global impacts of the changes of Arctic climate system,especially on China’s weather and climate,and demands for commercial utilization of the Arctic sea routes,Chinese scientists have made great progresses on in site and remote sensing observation technologies for Arctic Ocean,interaction mechanisms between atmosphere,sea ice,and ocean,the connection mechanism between the Arctic Ocean and other regions,and have achieved a series of research results.This study summarizes the research achievements by Chinese scientists in the above-mentioned aspects or beyond,identifies knowledge gaps,and based on this,discusses prospects and provides suggestions.From a perspective of observation,improving the observation capabilities of the Arctic Ocean in winter and the ocean under the ice,as well as floe-scale processes of sea ice and mesoscale and submesoscale processes of the ocean,is an urgent task to be addressed.Strengthening international cooperation is necessary for building a monitoring network for the Arctic marine environment.From a perspective of numerical simulation,the descriptive ability and parameterization scheme of sub-grid processes based on observational evidence need to be developed.From a perspective of cross-sphere interactions,in addition to the multi-media coupling within the Arctic Ocean that this review focuses on,the interaction between the Arctic Ocean and land or ice sheet(Greenland),especially the water cycle process,is also a scientific domain that needs to be considered,in the context of Arctic warming and humidification.From a perspective of climate effects,the physical mechanisms that affect the robustness of teleconnection need to be clarified.展开更多
The hurdle technology for food preservation effectively addresses the limitations of individual antimicrobial technologies by integrating their strengths.It can not only prolong the storage time of food but also maint...The hurdle technology for food preservation effectively addresses the limitations of individual antimicrobial technologies by integrating their strengths.It can not only prolong the storage time of food but also maintains its high quality.In this study,three antimicrobial and bactericidal technologies,namely soluble gas stabilization(SGS),modified atmosphere packaging(MAP),and cold plasma(CP),were applied to chilled chicken breasts.The packaging,total viable count(TVC),and physicochemical properties of chilled chicken breasts after treatments and storage at 4℃were monitored.The microbial diversity at the initial and end points of the storage time of each group was also analyzed.The results indicated that a 3−5 h SGS treatment can effectively increase the proportion of carbon dioxide in the MAP during the storage process of chilled chicken breasts,thereby alleviating the packaging collapse problem.Simultaneously,the effect of SGS,MAP,and CP combinational treatments significantly extended the storage time of chilled chicken breasts while maintaining the physicochemical qualities of samples.Compared to the control group,the TVC of chicken breast treated with SGS,MAP,and CP treatments decreased by 0.58(lg(CFU/g))at 0 day.The shelf life was extended by 5 days.After 8 days,the total volatile basic nitrogen(TVB-N)was 26.67 vs.19.50 mg/100 g,thiobarbituric acid reactive substances(TBARS)was 0.99 vs.0.72 mg MDA/kg,and TVC was 8.22 vs.6.52(lg(CFU/g)).High-throughput sequencing results showed that SGS and MAP treatments significantly reduce the proportion of Pseudomonas and Psychrobacter,which are sensitive to carbon dioxide,in the total bacterial genera.This study underscores the potential of integrating multiple antimicrobial technologies for effective food preservation.展开更多
The present study monitored bacterial succession,physicochemical properties,and volatile organic compounds(VOCs)changes in smoked chicken legs with modified atmosphere packaging(MAP,60% CO_(2) and 40%N_(2))during a 25...The present study monitored bacterial succession,physicochemical properties,and volatile organic compounds(VOCs)changes in smoked chicken legs with modified atmosphere packaging(MAP,60% CO_(2) and 40%N_(2))during a 25-day storage period at 4℃.After 15 days of storage,S erratia proteamaculans and Pseudomonas fragi became the predominant bacteria.Furthermore,physicochemical properties changed significantly,as evidenced by an increase in thiobarbituric acid reactive substances and b*(yellowness)value,and a decrease in hardness.A total of 65 VOCs were identified during storage.Correlation between bacterial succession and quality indicators(including VOCs and physicochemical properties)allowed the identification of 26 core dominant bacteria,including S.proteamaculans,Psychrobacter alimentarius,Pseudomonas putida,and Pseudomonas poae,which were positively related to spoilage VOCs(e.g.,1-octen-3-ol,1-pentanol,and 3-methyl-1-butanol)and could be defined as specific spoilage organisms(SSOs).The results of this study provide a systematic approach to predict SSOs in smoked chicken legs during storage,which can also provide a basis for product safety.展开更多
Atmospheric escape plays a critical role in shaping the long-term climate evolution of Mars.Among the various escape mechanisms,energetic neutral atoms(ENAs)generated through charge exchange between solar wind ions an...Atmospheric escape plays a critical role in shaping the long-term climate evolution of Mars.Among the various escape mechanisms,energetic neutral atoms(ENAs)generated through charge exchange between solar wind ions and exospheric neutrals serve as an important diagnostic for ion-neutral interactions and upper atmospheric loss.This study presents direct observations of hydrogen ENAs(H-ENAs)on the dayside of Mars by using the Mars Ion and Neutral Particle Analyzer(MINPA)onboard China’s Tianwen-1 orbiter.By analyzing H-ENA data during a coronal mass ejection and a stream interaction region from December 29,2021,to January 1,2022,and comparing these data with MAVEN/SWIA(Mars Atmosphere and Volatile EvolutioN/Solar Wind Ion Analyzer)solar wind measurements,we examine the temporal evolution of H-ENA flux and the associated sputtered escape of atmospheric constituents.The observed H-ENA velocity is consistent with upstream solar wind ions,and the H-ENA-to-ion intensity ratio is used to infer variations in exospheric density,revealing a delayed response to enhanced solar wind activity.Penetrating H-ENA intensities reach up to 5.3×10^(6)s^(−1) cm^(−2),with energy fluxes on the order of(0.5-8.1)×10^(−3) mW/m^(2).The estimated oxygen sputtered escape rate driven by penetrating H-ENAs ranges from 5.5×10^(23)s^(−1) to 5.2×10^(24)s^(−1),comparable to or exceeding previous estimates based on penetrating ions.The findings highlight the need for low-altitude H-ENA observations to better quantify their atmospheric interactions and refine our understanding of nonthermal escape processes at Mars.展开更多
Traditional large-scale multi-objective optimization algorithms(LSMOEAs)encounter difficulties when dealing with sparse large-scale multi-objective optimization problems(SLM-OPs)where most decision variables are zero....Traditional large-scale multi-objective optimization algorithms(LSMOEAs)encounter difficulties when dealing with sparse large-scale multi-objective optimization problems(SLM-OPs)where most decision variables are zero.As a result,many algorithms use a two-layer encoding approach to optimize binary variable Mask and real variable Dec separately.Nevertheless,existing optimizers often focus on locating non-zero variable posi-tions to optimize the binary variables Mask.However,approxi-mating the sparse distribution of real Pareto optimal solutions does not necessarily mean that the objective function is optimized.In data mining,it is common to mine frequent itemsets appear-ing together in a dataset to reveal the correlation between data.Inspired by this,we propose a novel two-layer encoding learning swarm optimizer based on frequent itemsets(TELSO)to address these SLMOPs.TELSO mined the frequent terms of multiple particles with better target values to find mask combinations that can obtain better objective values for fast convergence.Experi-mental results on five real-world problems and eight benchmark sets demonstrate that TELSO outperforms existing state-of-the-art sparse large-scale multi-objective evolutionary algorithms(SLMOEAs)in terms of performance and convergence speed.展开更多
文摘Open caissons are widely used in foundation engineering because of their load-bearing efficiency and adaptability in diverse soil conditions.However,accurately predicting their undrained bearing capacity in layered soils remains a complex challenge.This study presents a novel application of five ensemble machine(ML)algorithms-random forest(RF),gradient boosting machine(GBM),extreme gradient boosting(XGBoost),adaptive boosting(AdaBoost),and categorical boosting(CatBoost)-to predict the undrained bearing capacity factor(Nc)of circular open caissons embedded in two-layered clay on the basis of results from finite element limit analysis(FELA).The input dataset consists of 1188 numerical simulations using the Tresca failure criterion,varying in geometrical and soil parameters.The FELA was performed via OptumG2 software with adaptive meshing techniques and verified against existing benchmark studies.The ML models were trained on 70% of the dataset and tested on the remaining 30%.Their performance was evaluated using six statistical metrics:coefficient of determination(R²),mean absolute error(MAE),root mean squared error(RMSE),index of scatter(IOS),RMSE-to-standard deviation ratio(RSR),and variance explained factor(VAF).The results indicate that all the models achieved high accuracy,with R²values exceeding 97.6%and RMSE values below 0.02.Among them,AdaBoost and CatBoost consistently outperformed the other methods across both the training and testing datasets,demonstrating superior generalizability and robustness.The proposed ML framework offers an efficient,accurate,and data-driven alternative to traditional methods for estimating caisson capacity in stratified soils.This approach can aid in reducing computational costs while improving reliability in the early stages of foundation design.
基金supported by the National Natural Science Foundation of China(No.41772240)the Key Research and Development program of Jiangsu Province(No.BE2021637).
文摘Ball milling is an environmentally friendly technology for the remediation of petroleumcontaminated soil(PCS),but the cleanup of organic pollutants requires a long time,and the post-remediation soil needs an economically viable disposal/reuse strategy due to its vast volume.The present paper develops a ball milling process under oxygen atmosphere to enhance PCS remediation and reuse the obtained carbonized soil(BCS-O)as wastewater treatment materials.The total petroleum hydrocarbon removal rates by ball milling under vacuum,air,and oxygen atmospheres are 39.83%,55.21%,and 93.84%,respectively.The Langmuir and pseudo second-order models satisfactorily describe the adsorption capacity and behavior of BCS-O for transition metals.The Cu^(2+),Ni^(2+),and Mn^(2+)adsorbed onto BCS-O were mainly bound to metal carbonates and metal oxides.Furthermore,BCS-O can effectively activate persulfate(PDS)oxidation to degrade aniline,while BCS-O loaded with transition metal(BCS-O-Me)shows better activation efficiency and reusability.BCS-O and BCS-O-Me activated PDS oxidation systems are dominated by^(1)O_(2)oxidation and electron transfer.The main active sites are oxygen-containing functional groups,vacancy defects,and graphitized carbon.The oxygen-containing functional groups and vacancy defects primarily activate PDS to generate^(1)O_(2)and attack aniline.Graphitized carbon promotes aniline degradation by accelerating electron transfer.The paper develops an innovative strategy to simultaneously realize efficient remediation of PCS and sequential reuse of the postremediation soil.
基金supported by the National Natural Science Foundation of China(Grant Nos.12250013,12403070,12425306,42250101,12273092)the Macao Foundation,and Shanghai Post-doctoral Excellence Program(Grant No.2023000137)。
文摘The Sq(solar quiet)geomagnetic field is generated by the electric currents in the E-region of the ionosphere,driven by the atmospheric tides.It is a critical part of high-precision geomagnetic field modeling.Based on the classic thermal tide theory and atmospheric electrodynamics,this research,for the first time,developed an Sq geomagnetic field model that is directly built on the physical mechanism of the ionospheric dynamo,which is responsible for daily variations of the geomagnetic field.The performance in Sq geomagnetic field modeling was investigated using the Macao Science Satellite-1(MSS-1)data.Our model can enhance the physics-based framework of comprehensive geomagnetic field modeling for the MSS-1 and ensuing missions.
基金support from the National Natural Science Foundation of China(52174290).
文摘To explain the influence mechanism of MgO on the consolidation and reduction characteristics of roasted iron pellets,the properties and structure of pellets were investigated from multi-dimensions.It indicated that the MgO addition decreased the reduction swelling index(RSI)and reduction degree of pellets in both CO and H_(2)atmospheres.During the stepwise reduction process of Fe2O3→Fe3O4→FeO,the reduction behaviour of pellets in CO and H_(2)was similar,while the reduction rate of pellets in H_(2)atmosphere was almost twice as high as that in CO atmosphere.During the stepwise reduction process of FeO→Fe,the RSI of pellets showed a logarithmic increase in CO atmosphere and a linear decrease in H_(2)atmosphere.As investigated by first-principles calculations,C and Fe mainly formed chemical bonds,and the CO reduction process released energy,promoting the formation of iron whiskers.However,H and Fe produced weak physical adsorption,and the H_(2)reduction process was endothermic,inhibiting the generation of iron whiskers.With Mg2+doping in FexO,the nucleation region of iron whiskers expanded in CO reduction process,and the morphology of iron whiskers transformed from“slender”to“stocky,”reducing RSI of the pellets.
基金supported by MHRD as researcher C.K.Neog received the MHRD Institute GATE scholarship from Govt.of India.
文摘This study investigates the effects of radiation force due to the rotational pitch motion of a wave energy device,which comprises a coaxial bottom-mounted cylindrical caisson in a two-layer fluid,along with a submerged cylindrical buoy.The system is modeled as a two-layer fluid with infinite horizontal extent and finite depth.The radiation problem is analyzed in the context of linear water waves.The fluid domain is divided into outer and inner zones,and mathematical solutions for the pitch radiating potential are derived for the corresponding boundary valve problem in these zones using the separation of variables approach.Using the matching eigenfunction expansion method,the unknown coefficients in the analytical expression of the radiation potentials are evaluated.The resulting radiation potential is then used to compute the added mass and damping coefficients.Several numerical results for the added mass and damping coefficients are investigated for numerous parameters,particularly the effects of the cylinder radius,the draft of the submerged cylinder,and the density proportion between the two fluid layers across different frequency ranges.The major findings are presented and discussed.
基金supported by the Institute of Information&Communications Technology Planning&Evaluation(IITP)—Innovative Human Resource Development for Local Intellectualization program grant funded by the Korea government(MSIT)(IITP-2025-RS-2022-00156334)in part by Liaoning Province Nature Fund Project(2024-BSLH-214).
文摘Network Intrusion Detection System(NIDS)detection of minority class attacks is always a difficult task when dealing with attacks in complex network environments.To improve the detection capability of minority-class attacks,this study proposes an intrusion detection method based on a two-layer structure.The first layer employs a CNN-BiLSTM model incorporating an attention mechanism to classify network traffic into normal traffic,majority class attacks,and merged minority class attacks.The second layer further segments the minority class attacks through Stacking ensemble learning.The datasets are selected from the generic network dataset CIC-IDS2017,NSL-KDD,and the industrial network dataset Mississippi Gas Pipeline dataset to enhance the generalization and practical applicability of the model.Experimental results show that the proposed model achieves an overall detection accuracy of 99%,99%,and 95%on the CIC-IDS2017,NSL-KDD,and industrial network datasets,respectively.It also significantly outperforms traditional methods in terms of detection accuracy and recall rate for minority class attacks.Compared with the single-layer deep learning model,the two-layer structure effectively reduces the false alarm rate while improving the minority-class attack detection performance.The research in this paper not only improves the adaptability of NIDS to complex network environments but also provides a new solution for minority-class attack detection in industrial network security.
基金Supported by Talent Scientific Research Start-up Foundation of Wannan Medical College,No.WYRCQD2023045.
文摘BACKGROUND The early diagnosis rate of pancreatic ductal adenocarcinoma(PDAC)is low and the prognosis is poor.It is important to develop an interpretable noninvasive early diagnostic model in clinical practice.AIM To develop an interpretable noninvasive early diagnostic model for PDAC using plasma extracellular vesicle long RNA(EvlRNA).METHODS The diagnostic model was constructed based on plasma EvlRNA data.During the process of establishing the model,EvlRNA-index was introduced,and four algorithms were adopted to calculate EvlRNA-index.After the model was successfully constructed,performance evaluation was conducted.A series of bioinformatics methods were adopted to explore the potential mechanism of EvlRNA-index as the input feature of the model.And the relationship between key characteristics and PDAC were explored at the single-cell level.RESULTS A novel interpretable machine learning framework was developed based on plasma EvlRNA.In this framework,a two-layer classifier was established.A new concept was proposed:EvlRNA-index.Based on EvlRNA-index,a cancer diagnostic model was established,and a good diagnostic effect was achieved.The accuracy of PDACandCPvsHealth-Probabilistic PCA Index-SVM(PDAC and chronic pancreatitis vs health-probabilistic principal component analysis index-support vector machine)(1-18)was 91.51%,with Mathew’s correlation coefficient 0.7760 and area under the curve 0.9560.In the second layer of the model,the accuracy of PDACvsCP-Probabilistic PCA Index-RF(PDAC vs chronic pancreatitis-probabilistic principal component analysis index-random forest)(2-17)was 93.83%,with Mathew’s correlation coefficient 0.8422 and area under the curve 0.9698.Forty-nine PDAC-related genes were identified,among which 16 were known,inferring that the remaining ones were also PDAC-related genes.CONCLUSION An interpretable two-layer machine learning framework was proposed for early diagnosis and prediction of PDAC based on plasma EvlRNA,providing new insights into the clinical value of EvlRNA.
基金supported by the Basic Scientific Research Business Fund Project of Higher Education Institutions in Heilongjiang Province(145409601)the First Batch of Experimental Teaching and Teaching Laboratory Construction Research Projects in Heilongjiang Province(SJGZ20240038).
文摘In the wake of major natural disasters or human-made disasters,the communication infrastruc-ture within disaster-stricken areas is frequently dam-aged.Unmanned aerial vehicles(UAVs),thanks to their merits such as rapid deployment and high mobil-ity,are commonly regarded as an ideal option for con-structing temporary communication networks.Con-sidering the limited computing capability and battery power of UAVs,this paper proposes a two-layer UAV cooperative computing offloading strategy for emer-gency disaster relief scenarios.The multi-agent twin delayed deep deterministic policy gradient(MATD3)algorithm integrated with prioritized experience replay(PER)is utilized to jointly optimize the scheduling strategies of UAVs,task offloading ratios,and their mobility,aiming to diminish the energy consumption and delay of the system to the minimum.In order to address the aforementioned non-convex optimiza-tion issue,a Markov decision process(MDP)has been established.The results of simulation experiments demonstrate that,compared with the other four base-line algorithms,the algorithm introduced in this paper exhibits better convergence performance,verifying its feasibility and efficacy.
文摘Arsenic(As),classified as a Group I carcinogen by the International Agency for Research on Cancer(IARC),poses severe risks to ecosystems and human health through atmospheric exposure.This review synthesizes current knowledge on the sources,health impacts,and control strategies of atmospheric arsenic,with an emphasis on its global transport and toxicity.Natural sources,such as volcanic eruptions and soil erosion,contribute approximately 2.1 Gg/year;however,anthropogenic activities,notably metal smelting and coal combustion,dominate emissions,with global anthropogenic releases reaching approximately 28.6 Gg/year.Atmospheric arsenic primarily exists in two forms:particulate matter(PM_(2.5)-bound As(Ⅴ)/As(Ⅲ)and methylated species)and gaseous forms(e.g.,AsH_(3),As_(2)O_(3)),facilitating long-range transport and cross-continental pollution,as evidenced by Asian emissions contributing 39% of Arctic deposition.Advanced techniques,such as inductively coupled plasma mass spectrometry(ICP-MS)and models like GEOS-Chem,enhance emission tracking;however,gaps persist in monitoring gaseous arsenic and refining emission inventories.Health risks include lung cancer,neurotoxicity,and cardiovascular diseases,exacerbated by inhalation and dietary exposure via contaminated crops.Control technologies,including calcium-and iron-based adsorbents and industrial scrubbers,show promise but face challenges related to efficiency and cost.Regional strategies,such as China’s tightened emission limits(0.5 mg/m^(3))and the EU’s Best Available Techniques(BAT),highlight progress,yet global cooperation remains vital for transboundary mitigation.Future research should prioritize low-cost sensors,elucidating speciation-toxicity relationships,and AI-driven emission management to address data gaps and optimize policies.Integrating multidisciplinary approaches—advanced science,stringent regulations,and international collaboration—is crucial to mitigate the environmental and public health impacts of arsenic amid growing industrialization and climate change.
基金financial support for the research and for the publication costs of the articlesupported by Santa Catarina State Research Support Foundation(FAPESC)National Council for Scientific and Technological Development(CNPq no 302903/2023-2).
文摘Cement production,while essential for global infrastructure,contributes significantly to carbon dioxide emissions,accounting for approximately 7%of total emissions.To mitigate these environmental impacts,flash calcination of kaolinitic clays has been investigated as a sustainable alternative.This technique involves the rapid heating of clays,enabling their use as supplementary cementitious materials.The primary objective of this study was to modify the color of calcined clay in various atmospheres(oxidizing,inert,and reducing)to achieve a grayish tone similar to commercial cement while preserving its reactive properties.The experimental procedure employed a tubular reactor with precise control of gas flows(atmospheric air,nitrogen,and a carbon monoxide–nitrogen mixture).Physicochemical characterization of the raw clay was conducted before calcination,with analyses repeated on the calcined clays following experimentation.Results indicated that clay calcined in an oxidizing atmosphere acquired a reddish hue,attributed to the oxidation of iron in hematite.The Clay exhibited a pinkish tone in an inert atmosphere,while calcination in a reducing atmosphere yielded the desired grayish color.Regarding pozzolanic activity,clays calcined in oxidizing and inert atmospheres displayed robust strength,ranging from 82%to 87%.Calcination in a reducing atmosphere resulted in slightly lower strength,around 74%,likely due to the clay’s chemical composition and the calcination process,which affects compound formation and material reactivity.
基金supported by the National Natural Science Foundation of China(Grant Numbers 42374195 and 42188101)the fellowship of China National Postdoctoral Program for Innovative Talents(Grant Number BX20230273)+1 种基金the Hubei Provincial Natural Science Foundation of China(Grant Number 2024AFB-097)the Postdoctor Project of Hubei Province(Grant Number 2024HBBHCXA054).
文摘This study employs Principal Component Analysis(PCA)and 13 years of SD-WACCM-X model data(2007-2019)to investigate the characteristics and mechanisms of Inter-hemispheric Coupling(IHC)triggered by sudden stratospheric warming(SSW)events.IHC in both hemispheres leads to a cold anomaly in the equatorial stratosphere,a warm anomaly in the equatorial mesosphere,and increased temperatures in the mesosphere and lower thermosphere(MLT)region of the summer hemisphere.However,the IHC features during boreal winter period are significantly weaker than during the austral winter period,primarily due to weaker stationary planetary wave activity in the Southern Hemisphere(SH).During the austral winter period,IHC results in a warm anomaly in the polar mesosphere of the SH,which does not occur in the NH during boreal winter period.This study also examines the possible influence of quasi-two-day waves(QTDWs)on IHC.We found that the largest temperature anomaly in the summer polar MLT region is associated with a large wind instability area,and a well-developed critical layer structure of QTDW in January.In contrast,during July,despite favorable conditions for QTDW propagation in the Northern Hemisphere,weaker IHC response is observed,suggesting that IHC features and the relationship with QTDWs during July would be more complex than during January.
文摘The direct deoxygenative homo-coupling of benzyl alcohols holds great promise to build up bibenzyl motifs in organic synthesis,yet it remains a grand challenge in selectivity and activity control.Herein,we first discovered that iron carbide catalysts displayed high efficiency and selectivity in the catalytic deoxygenative homo-coupling of benzyl alcohols into bibenzyls using H_(2)as the reductant.Ir-promoted Fe0@Fe_(5)C_(2)gave the best performance among the investigated catalysts,and a broad scope of substrates with diverse functional groups could be smoothly converted into bibenzyls,with the yield up to 85%.In addition,in the presence of alkenes,three-component coupling reactions between alcohols and alkenes were also for the first time achieved to construct more complex multi-ring molecules.The radical-trapping experiment and FTIR measurements revealed the radical nature of the reaction and the significantly promoted C–O bond activation after carbonization,respectively.This work will provide guidelines for the rational design of efficient and selective catalysts for the alcohol-involved carbon-carbon coupling reactions.
基金supported by the National Key R&D Program of China[grant number 2022YFF0801603]the Natural Science Foundation of China[grant number 41905074].
文摘Due to the high elevation and cold climate of the Tibetan Plateau,the western region retains extensive snow cover during the summer,which can exhibit rapid variability over the course of just a few days.This study utilizes numerical experiments to investigate the atmospheric response to extreme Tibetan Plateau snow cover(TPSC)events on a subseasonal timescale during summer.The results indicate that the subseasonal variations in TPSC exert limited impact on nonlocal atmospheric circulation and temperature during this period.Nevertheless,local surface energy and atmospheric temperature exhibit rapid cooling responses to increased snow cover.Specifically,an increase in snow cover over the western Tibetan Plateau leads to a sharp rise in surface albedo,resulting in a reduction in land surface energy and a negative response in the diabatic heating rate from the surface to 350 hPa locally.This negative diabatic heating response subsequently causes a decline in both surface and overlying atmospheric temperatures.The temperature response is confined to the western Tibetan Plateau and extends vertically from the surface to approximately 350 hPa.These extreme TPSC events and their associated atmospheric impacts occur within a two-week timescale.
基金Supported by the Shanghai Rising Star Program (Grant No. 21QB1403900)the Shanghai Municipal Commission of Science and Technology (Grant No. 22170712600)。
文摘Knowing the optimal operating parameters of Stirling engines is important for efficient combustion through adaptability to changed pressures and oxygen atmospheres. In this study, the optimum operating conditions for efficient combustion in a singular Stirling engine combustor at different oxygen atmospheres were investigated and determined. Numerical simulations were performed to investigate the effects of ejection ratio and pressure on combustion performance. In an oxygen/carbon dioxide atmosphere, the results show that increasing the ejection ratio substantially alters the flame distribution in the Stirling engine combustor, increasing heat transfer and external combustion efficiency. In contrast, increasing the ejection ratio reduces the average and maximum temperatures of the Stirling engine combustor. Increased pressure affects the flame distribution in the Stirling engine combustor and impedes the flow and convective heat transfer in the combustor, reducing the overall external combustion efficiency at pressures above 6.5 MPa. In an air/carbon dioxide atmosphere, an increased ejection ratio reduces the average and maximum temperatures in the Stirling engine combustor. However, the overall flame distribution does not change substantially. The external combustion efficiency tends to increase and then decrease because of two opposing factors: the increase in the convective heat transfer coefficient and the decrease in the temperature difference. Increasing pressure inhibits forced convection heat transfer in the Stirling engine combustor, reducing external combustion efficiency, which drops from 78% to 65% when pressure increases from 0.2 MPa to 0.5 MPa.
基金Project supported by the Key Research Project of Colleges and Universities of Henan Province(Grant No.23A140017)the Research Project of Department of Science and Technology of Henan Province(Grant No.242102231072)+1 种基金the National Natural Sciences Foundation of China(Grant No.52402336)the special fund of the Ningbo Institute of Materials Technology and Engineering,Chinese Academy of Sciences“New magnetic materials and structural devices for 5G communication”(Grant No.E41602QB01).
文摘CaBaCo_(4)O_(7)has been widely studied because of its distinctive structure and magnetic properties.This study examined the influence of different cooling atmospheres on the structure,magnetic properties,and dielectric behavior of CaBaCo_(4)O_(7).Samples were cooled under different atmospheric conditions to assess these influences.Our findings indicate that reduced oxygen content leads to increased lattice distortion.Since oxygen atoms play a crucial role in mediating magnetic exchange,oxygen deficiency disrupts long-range magnetic order and promotes short-range antiferromagnetic interactions.Additionally,the cooling atmosphere significantly impacts grain size,thereby affecting the dielectric constant and dielectric loss.In the argon-cooled CaBaCo_(4)O_(7)(Ar)sample,oxygen deficiency reduced dielectric permittivity and increased dielectric loss.
基金The National Natural Science Foundation of China under contract Nos 42325604 and 42276253the Program of Shanghai Academic/Technology Research Leader under contract No.22XD1403600the Fund of the Ministry of Industry and Information Technology of China under contract No.CBG2N21-2-1.
文摘The year,2024,marks the 40th anniversary of Chinese research expeditions in the polar regions and the 25th anniversary of its Arctic research expeditions.China has conducted 14 national Arctic research expeditions.With the increase of understandings on the global impacts of the changes of Arctic climate system,especially on China’s weather and climate,and demands for commercial utilization of the Arctic sea routes,Chinese scientists have made great progresses on in site and remote sensing observation technologies for Arctic Ocean,interaction mechanisms between atmosphere,sea ice,and ocean,the connection mechanism between the Arctic Ocean and other regions,and have achieved a series of research results.This study summarizes the research achievements by Chinese scientists in the above-mentioned aspects or beyond,identifies knowledge gaps,and based on this,discusses prospects and provides suggestions.From a perspective of observation,improving the observation capabilities of the Arctic Ocean in winter and the ocean under the ice,as well as floe-scale processes of sea ice and mesoscale and submesoscale processes of the ocean,is an urgent task to be addressed.Strengthening international cooperation is necessary for building a monitoring network for the Arctic marine environment.From a perspective of numerical simulation,the descriptive ability and parameterization scheme of sub-grid processes based on observational evidence need to be developed.From a perspective of cross-sphere interactions,in addition to the multi-media coupling within the Arctic Ocean that this review focuses on,the interaction between the Arctic Ocean and land or ice sheet(Greenland),especially the water cycle process,is also a scientific domain that needs to be considered,in the context of Arctic warming and humidification.From a perspective of climate effects,the physical mechanisms that affect the robustness of teleconnection need to be clarified.
基金supported by the National Natural Science Foundation of China(32272252)the China Agriculture Research System(CARS-41)funded by the Chinese Ministry of Agriculture and Rural Affairs and Wens Fifth Five R&D Major Project(WENS-2020-1-ZDZX-007).
文摘The hurdle technology for food preservation effectively addresses the limitations of individual antimicrobial technologies by integrating their strengths.It can not only prolong the storage time of food but also maintains its high quality.In this study,three antimicrobial and bactericidal technologies,namely soluble gas stabilization(SGS),modified atmosphere packaging(MAP),and cold plasma(CP),were applied to chilled chicken breasts.The packaging,total viable count(TVC),and physicochemical properties of chilled chicken breasts after treatments and storage at 4℃were monitored.The microbial diversity at the initial and end points of the storage time of each group was also analyzed.The results indicated that a 3−5 h SGS treatment can effectively increase the proportion of carbon dioxide in the MAP during the storage process of chilled chicken breasts,thereby alleviating the packaging collapse problem.Simultaneously,the effect of SGS,MAP,and CP combinational treatments significantly extended the storage time of chilled chicken breasts while maintaining the physicochemical qualities of samples.Compared to the control group,the TVC of chicken breast treated with SGS,MAP,and CP treatments decreased by 0.58(lg(CFU/g))at 0 day.The shelf life was extended by 5 days.After 8 days,the total volatile basic nitrogen(TVB-N)was 26.67 vs.19.50 mg/100 g,thiobarbituric acid reactive substances(TBARS)was 0.99 vs.0.72 mg MDA/kg,and TVC was 8.22 vs.6.52(lg(CFU/g)).High-throughput sequencing results showed that SGS and MAP treatments significantly reduce the proportion of Pseudomonas and Psychrobacter,which are sensitive to carbon dioxide,in the total bacterial genera.This study underscores the potential of integrating multiple antimicrobial technologies for effective food preservation.
基金funded by the National Natural Science Foundation of China(U22A20547)the Major Science and Technology Projects of Heilongjiang Province(2021ZX12B05 and 2020ZX07B02)。
文摘The present study monitored bacterial succession,physicochemical properties,and volatile organic compounds(VOCs)changes in smoked chicken legs with modified atmosphere packaging(MAP,60% CO_(2) and 40%N_(2))during a 25-day storage period at 4℃.After 15 days of storage,S erratia proteamaculans and Pseudomonas fragi became the predominant bacteria.Furthermore,physicochemical properties changed significantly,as evidenced by an increase in thiobarbituric acid reactive substances and b*(yellowness)value,and a decrease in hardness.A total of 65 VOCs were identified during storage.Correlation between bacterial succession and quality indicators(including VOCs and physicochemical properties)allowed the identification of 26 core dominant bacteria,including S.proteamaculans,Psychrobacter alimentarius,Pseudomonas putida,and Pseudomonas poae,which were positively related to spoilage VOCs(e.g.,1-octen-3-ol,1-pentanol,and 3-methyl-1-butanol)and could be defined as specific spoilage organisms(SSOs).The results of this study provide a systematic approach to predict SSOs in smoked chicken legs during storage,which can also provide a basis for product safety.
基金supported by the National Natural Science Foundation of China (Grant Nos. 42188101, 42274211, 41974170, 42374184, 42122032, and 41974196)the Chinese Academy of Sciences (Grant Nos. QYZDJSSW-JSC028, XDA15052500, XDA17010301, and XDB41000000)+3 种基金the CNSA (Grant No. D050103)the Specialized Research Fund for State Key Laboratories of Chinathe Specialized Research Fund for Laboratory of Geospace Environment of the University of Science and Technology of Chinasupported by the International Space Science Institute (ISSI) in Bern and Beijing through the ISSI/ISSI-BJ International Team Project titled “Understanding the Mars Space Environment Through Multi-Spacecraft Measurements” (ISSI Team Project No. 23-582 and ISSI-BJ Team Project No. 58)
文摘Atmospheric escape plays a critical role in shaping the long-term climate evolution of Mars.Among the various escape mechanisms,energetic neutral atoms(ENAs)generated through charge exchange between solar wind ions and exospheric neutrals serve as an important diagnostic for ion-neutral interactions and upper atmospheric loss.This study presents direct observations of hydrogen ENAs(H-ENAs)on the dayside of Mars by using the Mars Ion and Neutral Particle Analyzer(MINPA)onboard China’s Tianwen-1 orbiter.By analyzing H-ENA data during a coronal mass ejection and a stream interaction region from December 29,2021,to January 1,2022,and comparing these data with MAVEN/SWIA(Mars Atmosphere and Volatile EvolutioN/Solar Wind Ion Analyzer)solar wind measurements,we examine the temporal evolution of H-ENA flux and the associated sputtered escape of atmospheric constituents.The observed H-ENA velocity is consistent with upstream solar wind ions,and the H-ENA-to-ion intensity ratio is used to infer variations in exospheric density,revealing a delayed response to enhanced solar wind activity.Penetrating H-ENA intensities reach up to 5.3×10^(6)s^(−1) cm^(−2),with energy fluxes on the order of(0.5-8.1)×10^(−3) mW/m^(2).The estimated oxygen sputtered escape rate driven by penetrating H-ENAs ranges from 5.5×10^(23)s^(−1) to 5.2×10^(24)s^(−1),comparable to or exceeding previous estimates based on penetrating ions.The findings highlight the need for low-altitude H-ENA observations to better quantify their atmospheric interactions and refine our understanding of nonthermal escape processes at Mars.
基金supported by the Scientific Research Project of Xiang Jiang Lab(22XJ02003)the University Fundamental Research Fund(23-ZZCX-JDZ-28)+5 种基金the National Science Fund for Outstanding Young Scholars(62122093)the National Natural Science Foundation of China(72071205)the Hunan Graduate Research Innovation Project(ZC23112101-10)the Hunan Natural Science Foundation Regional Joint Project(2023JJ50490)the Science and Technology Project for Young and Middle-aged Talents of Hunan(2023TJ-Z03)the Science and Technology Innovation Program of Humnan Province(2023RC1002)。
文摘Traditional large-scale multi-objective optimization algorithms(LSMOEAs)encounter difficulties when dealing with sparse large-scale multi-objective optimization problems(SLM-OPs)where most decision variables are zero.As a result,many algorithms use a two-layer encoding approach to optimize binary variable Mask and real variable Dec separately.Nevertheless,existing optimizers often focus on locating non-zero variable posi-tions to optimize the binary variables Mask.However,approxi-mating the sparse distribution of real Pareto optimal solutions does not necessarily mean that the objective function is optimized.In data mining,it is common to mine frequent itemsets appear-ing together in a dataset to reveal the correlation between data.Inspired by this,we propose a novel two-layer encoding learning swarm optimizer based on frequent itemsets(TELSO)to address these SLMOPs.TELSO mined the frequent terms of multiple particles with better target values to find mask combinations that can obtain better objective values for fast convergence.Experi-mental results on five real-world problems and eight benchmark sets demonstrate that TELSO outperforms existing state-of-the-art sparse large-scale multi-objective evolutionary algorithms(SLMOEAs)in terms of performance and convergence speed.
