Observations of transmission spectra reveal that hot Jupiters and Neptunes are likely to possess escaping atmospheres driven by stellar radiation.Numerous models predict that magnetic fields may exert significant infl...Observations of transmission spectra reveal that hot Jupiters and Neptunes are likely to possess escaping atmospheres driven by stellar radiation.Numerous models predict that magnetic fields may exert significant influences on the atmospheres of hot planets.Generally,the escaping atmospheres are not entirely ionized,and magnetic fields only directly affect the escape of ionized components within them.Considering the chemical reactions between ionized components and neutral atoms,as well as collision processes,magnetic fields indirectly impact the escape of neutral atoms,thereby influencing the detection signals of planetary atmospheres in transmission spectra.In order to simulate this process,we developed a magnetohydrodynamic multi-fluid model based on MHD code PLUTO.As an initial exploration,we investigated the impact of magnetic fields on the decoupling of H^(+)and H in the escaping atmosphere of the hot Neptune GJ436b.Due to the strong resonant interactions between H and H^(+),the coupling between them is tight even if the magnetic field is strong.Of course,alternatively,our work also suggests that merging H and H^(+)into a single flow can be a reasonable assumption in MHD simulations of escaping atmospheres.However,our simulation results indicate that under the influence of magnetic fields,there are noticeable regional differences in the decoupling of H^(+)and H.With the increase of magnetic field strength,the degree of decoupling also increases.For heavier particles such as O,the decoupling between O and H^(+)is more pronounced.Our findings provide important insights for future studies on the decoupling processes of heavy atoms in the escaping atmospheres of hot Jupiters and hot Neptunes under the influence of magnetic fields.展开更多
Appropriate physical exercise has a positive impact on adolescents’physical and mental health,but there is a serious lack of physical exercise among Chinese adolescents.How to shape their exercise behavior(EB)has bec...Appropriate physical exercise has a positive impact on adolescents’physical and mental health,but there is a serious lack of physical exercise among Chinese adolescents.How to shape their exercise behavior(EB)has become an important task in promoting their development.A questionnaire survey was conducted using stratified cluster random sampling on three middle schools by class in Zhejiang Province,China to investigate the impact of exercise atmosphere(EA)on adolescents’exercise behavior and the mediating role of exercise identity(EI)and exercise habit(EH).806 adolescents were investigated by the Exercise Atmosphere Scale(EAS),Exercise-Identity Scale(EIS),Self-Report Habit Index(SRHI),and Physical Activity Rating Scale(PARS-3).The results show that:There is a significant positive correlation between each two of exercise atmosphere,exercise identity,exercise habit,and exercise behavior(p<0.05).Exercise atmosphere could not only directly affect adolescents’physical exercise behavior but can also indirectly affect their physical exercise behavior through the mediating effect of exercise identity and exercise habit,involving three mediating pathways,namely,the mediating path through exercise identity,the mediating pathway through exercise habit and the chain mediating pathway through exercise identity and exercise habit.The direct effect of exercise atmosphere on exercise behavior was 0.459(p<0.01),accounting for 62.62% of the total effect of 0.733,and its indirect effect was 0.274,accounting for 37.28% of the total effect.To a certain extent,the mediating effect model reveals the mechanism of exercise atmosphere affecting exercise behavior and has a certain reference value for promoting adolescents’exercise behavior.We should start by creating an exercise atmosphere,cultivating exercise identity,and enhancing exercise habits to help teenagers form active physical exercise behaviors.展开更多
In this study,the impact of different reaction times on the preparation of powdered activated carbon(PAC)using a one-step rapid activation method under flue gas atmosphere is investigated,and the underlying reaction m...In this study,the impact of different reaction times on the preparation of powdered activated carbon(PAC)using a one-step rapid activation method under flue gas atmosphere is investigated,and the underlying reaction mechanism is summarized.Results indicate that the reaction process of this method can be divided into three stages:stage I is the rapid release of volatiles and the rapid consumption of O_(2),primarily occurring within a reaction time range of 0-0.5 s;stage II is mainly the continuous release and diffusion of volatiles,which is the carbonization and activation coupling reaction stage,and the carbonization process is the main in this stage.This stage mainly occurs at the reaction time range of 0.5 -2.0 s when SL-coal is used as material,and that is 0.5-3.0 s when JJ-coal is used as material;stage III is mainly the activation stage,during which activated components diffuse to both the surface and interior of particles.This stage mainly involves the reaction stage of CO_(2)and H2O(g)activation,and it mainly occurs at the reaction time range of 2.0-4.0 s when SL-coal is used as material,and that is 3.0-4.0 s when JJ-coal is used as material.Besides,the main function of the first two stages is to provide more diffusion channels and contact surfaces/activation sites for the diffusion and activation of the activated components in the third stage.Mastering the reaction mechanism would serve as a crucial reference and foundation for designing the structure,size of the reactor,and optimal positioning of the activator nozzle in PAC preparation.展开更多
In an era of scene-based consumption,the essence of operating a bookstore lies in accepting and enabling the bookstore to play its role as a cultural medium for browsing and appreciating books,which in turn fosters th...In an era of scene-based consumption,the essence of operating a bookstore lies in accepting and enabling the bookstore to play its role as a cultural medium for browsing and appreciating books,which in turn fosters the development of a distinctive bookstore culture.This new type of consumption context has led to an evolution in the book-reading culture in physical bookstores that is characterized by a shift from a paradigm of passive reading to one where the emphasis is on interactive viewing.This transition has laid the foundation for the creation of cultural atmospheres in bookstores,and it highlights the visual interactions that now exist between readers and books as well as with other related cultural industries.The dominant and fundamental logic behind this process is symbiosis,experience,aesthetics,immersion,and creativity.However,when a form of culture that focuses on consumption-oriented browsing begins to overshadow knowledge acquisition during the process of book reading,the cultural essence of bookstores is likely to be diminished.Therefore,the cultural essence within the scene-based consumption context should be enhanced by creating innovative viewing activities that showcase the cultural and emotional implications inherent in the scene itself,and thus help to align the identity of the bookstore with its in-situ cultural space.展开更多
Here,we aimed to study the changes in proteome of golden pompano fillets during post-mortem storage.Tandem mass tags(TMT)-labeled quantitative proteomic strategy was applied to investigate the relationships between pr...Here,we aimed to study the changes in proteome of golden pompano fillets during post-mortem storage.Tandem mass tags(TMT)-labeled quantitative proteomic strategy was applied to investigate the relationships between protein changes and quality characteristics of modified atmosphere packaging(MAP)fillets during superchilling(-3°C)storage.Scanning electron microscopy was used to show that the muscle histology microstructure of fillets was damaged to varying degrees,and low-field nuclear magnetic resonance was used to find that the immobilized water and free water in the muscle of fillets changed significantly.Total sulfhydryl content,TCA-soluble peptides and Ca2+-ATPase activity also showed that the fillet protein had a deterioration by oxidation and denaturation.The Fresh(FS),MAP,and air packaging(AP)groups were set.Total of 150 proteins were identified as differential abundant proteins(DAPs)in MAP/FS,while 209 DAPs were in AP/FS group.The KEGG pathway analysis indicated that most DAPs were involved in binding proteins and protein turnover.Correlation analysis found that 52 DAPs were correlated with quality traits.Among them,8 highly correlated DAPs are expected to be used as potential quality markers for protein oxidation and water-holding capacity.These results provide a further understanding of the muscle deterioration mechanism of packaging golden pompano fillets during superchilling.展开更多
The present work aims to investigate the effect of heating temperature(400,600 and 800°C)and inoculating elements(Ca,Ca-Ba,Ca-RE)on oxidation behavior of ductile irons containing 5.25%Si and 4.8%Si-2.3%Mo in dry ...The present work aims to investigate the effect of heating temperature(400,600 and 800°C)and inoculating elements(Ca,Ca-Ba,Ca-RE)on oxidation behavior of ductile irons containing 5.25%Si and 4.8%Si-2.3%Mo in dry air and combustion gas containing water vapour(natural gas burning).The oxidation is influenced by the gas atmosphere type,the iron alloying system,and the inoculating elements depending on the heating temperature.The weight gain increases from 0.001%-0.1%(400°C)to 0.05%-0.70%(600°C)and up to 0.10%-2.15%(800°C).No particular effects of the considered influencing factors are found when heating at 400°C,while at 600°C,mainly the oxidation gas atmosphere type shows a visible influence.At the highest heating temperature of 800°C,a limited increase of the weight gain is found for dry air atmosphere(up to 0.25%),but it drastically increases for combustion atmospheres(0.65%-2.15%).The water vapour presence in the combustion atmosphere is an important oxidising factor at 600-800°C.The alloying system appears to influence the oxidation behavior mainly at a heating temperature of 800°C in the combustion atmosphere,as evidenced by the lower weight gain in 5.25%silicon cast iron.Positive effects of inoculating elements increase with the heating temperature,with Ca and Ba-FeSi inoculation generally showing better performance.Irons inoculated with CaRE-FeSi exhibit a higher degree of oxidation.These results are in good relationship with the previous reported data:Ca-Ba-inoculation system appears to be better than simple Ca for improving the graphite parameters,while RE-bearing inoculant negatively affects the compactness degree of graphite particles in high-Si ductile irons.As the lower compactness degree is typical for graphite nodules in high-Si ductile irons,which negatively affects the oxidation resistance,it is necessary to employ specific metallurgical treatments to improve nodule quality.Inoculation,in particular,is a potential method to achieve this improvement.展开更多
This study mainly monitored the dominant bacterial populations and identified the spoilage-related microorganisms of braised chicken meat stored under different CO_(2)-modified atmosphere packaging(MAP)during refriger...This study mainly monitored the dominant bacterial populations and identified the spoilage-related microorganisms of braised chicken meat stored under different CO_(2)-modified atmosphere packaging(MAP)during refrigerated storage using a culture-dependent method and 16S rDNA identification.The quality changes and shelf life of the meat were also measured.The growth rate of total viable count(TVC)in braised chicken was slower with an increase of CO_(2) content in MAP,which also occurred in the remaining bacterial species monitored(lactic acid bacteria,Pseudomonas spp.,Brochothrix thermosphacta).The MAP exerted beneficial effects on the quality of braised chicken,as demonstrated by retarding the production of total volatile basic nitrogen(TVB-N)and delaying lipid oxidation(TBARS test).A total of 14 isolates were identified from braised chickens with different packaging at the end of storage,these included P.fragi(6 isolates),P.psychrophila(2 isolates),Enterococcus faecalis(3 isolates),B.thermosphacta(2 isolates),Staphylococcus equorum(1 isolate).展开更多
To realize the comprehensive utilization of ludwigite ore,an integrated and efficient route for the boron and iron separation was proposed in this work,which via soda-ash roasting under CO–CO_(2)–N_(2) atmosphere fo...To realize the comprehensive utilization of ludwigite ore,an integrated and efficient route for the boron and iron separation was proposed in this work,which via soda-ash roasting under CO–CO_(2)–N_(2) atmosphere followed by grind-leaching,magnetic separation,and CO_(2) carbonation.The effects of roasting temperature,roasting time,CO/(CO+CO_(2))composition,and Na_(2)CO_(3) dosage on the boron and iron separation indices were primarily investigated.Under the optimized conditions of the roasting temperature of 850℃,roasting time of 60 min,soda ash dosage of 20 wt%,and CO/(CO+CO_(2)) of 10 vol%,92%of boron was leached during wet grinding,and 88.6%of iron was recovered during the magnetic separation and magnetic concentrate with a total iron content of 61.51 wt%.Raman spectra and^(11)B NMR results indicated that boron exists asB(OH)_(4)^(-) in the leachate,from which high-purity borax pentahydrate could be prepared by CO_(2) carbonation.展开更多
This work constructed a machine learning(ML)model to predict the atmospheric corrosion rate of low-alloy steels(LAS).The material properties of LAS,environmental factors,and exposure time were used as the input,while ...This work constructed a machine learning(ML)model to predict the atmospheric corrosion rate of low-alloy steels(LAS).The material properties of LAS,environmental factors,and exposure time were used as the input,while the corrosion rate as the output.6 dif-ferent ML algorithms were used to construct the proposed model.Through optimization and filtering,the eXtreme gradient boosting(XG-Boost)model exhibited good corrosion rate prediction accuracy.The features of material properties were then transformed into atomic and physical features using the proposed property transformation approach,and the dominant descriptors that affected the corrosion rate were filtered using the recursive feature elimination(RFE)as well as XGBoost methods.The established ML models exhibited better predic-tion performance and generalization ability via property transformation descriptors.In addition,the SHapley additive exPlanations(SHAP)method was applied to analyze the relationship between the descriptors and corrosion rate.The results showed that the property transformation model could effectively help with analyzing the corrosion behavior,thereby significantly improving the generalization ability of corrosion rate prediction models.展开更多
The spring atmospheric heat source(AHS)over the Tibetan Plateau(TP)has been suggested to affect the Asian summer monsoon and summer precipitation over South China.However,its influence on the summer precipitation in N...The spring atmospheric heat source(AHS)over the Tibetan Plateau(TP)has been suggested to affect the Asian summer monsoon and summer precipitation over South China.However,its influence on the summer precipitation in Northeast China(NEC)remains unknown.The connection between spring TP AHS and subsequent summer precipitation over NEC from 1961 to 2020 is analyzed in this study.Results illustrate that stronger spring TP AHS can enhance subsequent summer NEC precipitation,and higher soil moisture in the Yellow River Valley-North China region(YRVNC)acts as a bridge.During spring,the strong TP AHS could strengthen the transportation of water vapor to East China and lead to excessive rainfall in the YRVNC.Thus,soil moisture increases,which regulates local thermal conditions by decreasing local surface skin temperature and sensible heat.Owing to the memory of soil moisture,the lower spring sensible heat over the YRVNC can last until mid-summer,decrease the land–sea thermal contrast,and weaken the southerly winds over the East Asia–western Pacific region and convective activities over the South China Sea and tropical western Pacific.This modulates the East Asia–Pacific teleconnection pattern,which leads to a cyclonic anomaly and excessive summer precipitation over NEC.展开更多
Microplastics,plastic particles smaller than 5 mm in size,are a growing source of environmental pollution.Microplastic pollution has been observed in situ in the remote Arctic,where it has been found in the land,sea,c...Microplastics,plastic particles smaller than 5 mm in size,are a growing source of environmental pollution.Microplastic pollution has been observed in situ in the remote Arctic,where it has been found in the land,sea,cryosphere,and atmosphere.This review summarizes the sample pretreatment techniques and analytical methods commonly used in microplastic research,as well as the pollution status of microplastics in the Arctic,their sources,and their effects on the environment.In the Arctic,the size distribution of microplastics is more inclined to small-scale aggregation,the shape of microplastics is mostly fibrous,with the proportion of fibers often accounting for more than 70%.There are marked differences among studies in terms of abundance and polymer composition,but polyester is generally dominant in seawater.Many microplastic particles are transported to the Arctic by ocean currents and rivers,but atmospheric transport and deposition are slowly being recognized as an important transport route.Sea ice is particularly important for the temporary storage,transport,and release of Arctic microplastics.The average storage of microplastics in sea ice was estimated to be approximately 6.1×108 items.Given their properties,microplastics can affect glacier melting,sea surface temperature changes,and even the carbon cycle.Urgent measures must be taken to improve research standards and overcome sampling difficulties in the Arctic region to achieve time continuity and large-scale distribution patterns of Arctic microplastics.展开更多
To quantify the relative contributions of Arctic sea ice and unforced atmospheric internal variability to the “warm Arctic, cold East Asia”(WACE) teleconnection, this study analyses three sets of large-ensemble simu...To quantify the relative contributions of Arctic sea ice and unforced atmospheric internal variability to the “warm Arctic, cold East Asia”(WACE) teleconnection, this study analyses three sets of large-ensemble simulations carried out by the Norwegian Earth System Model with a coupled atmosphere–land surface model, forced by seasonal sea ice conditions from preindustrial, present-day, and future periods. Each ensemble member within the same set uses the same forcing but with small perturbations to the atmospheric initial state. Hence, the difference between the present-day(or future) ensemble mean and the preindustrial ensemble mean provides the ice-loss-induced response, while the difference of the individual members within the present-day(or future) set is the effect of atmospheric internal variability. Results indicate that both present-day and future sea ice loss can force a negative phase of the Arctic Oscillation with a WACE pattern in winter. The magnitude of ice-induced Arctic warming is over four(ten) times larger than the ice-induced East Asian cooling in the present-day(future) experiment;the latter having a magnitude that is about 30% of the observed cooling. Sea ice loss contributes about 60%(80%) to the Arctic winter warming in the present-day(future) experiment. Atmospheric internal variability can also induce a WACE pattern with comparable magnitudes between the Arctic and East Asia. Ice-lossinduced East Asian cooling can easily be masked by atmospheric internal variability effects because random atmospheric internal variability may induce a larger magnitude warming. The observed WACE pattern occurs as a result of both Arctic sea ice loss and atmospheric internal variability, with the former dominating Arctic warming and the latter dominating East Asian cooling.展开更多
The regulating nitrogen content of diamond in a hydrogen-rich high-temperature and high-pressure(HPHT) growth environment was systematically investigated in this work by developing three growth systems,namely, "F...The regulating nitrogen content of diamond in a hydrogen-rich high-temperature and high-pressure(HPHT) growth environment was systematically investigated in this work by developing three growth systems,namely, "FeNi+Ti", "FeNi+G_(3)N_(6)H_(6)",and "FeNi+Ti+C_(3)N_(6)H_(6)".Optical microscopy,infrared spectroscopy,and photoluminescence(PL)spectroscopy measurements were conducted to analyze the spectroscopic characteristics of diamonds grown in these three systems.From our analysis,it was demonstrated that the presence of hydrogen in the sp^(3) hybrid C-H does not directly affect the color of the diamond and facilitates the increase of the nitrogen-vacancy(NV) center concentration in a highnitrogen-content diamond.In addition,titanium plays an important role in nitrogen removal,while its impact on hydrogen doping within the diamond lattice is insignificant.Most importantly,by regulating the ratio of nitrogen impurities that coexist in the nitrogen and hydrogen HPHT environment,the production of hydrogenous Ⅱa-type diamond,hydrogenous Ib-type diamond,and hydrogenous high-nitrogen-type diamonds was achieved with a nitrogen content of less than 1 ppm to 1600 ppm.展开更多
We report the transit observations of the ultra-hot Jupiter WASP-121b using the Goodman High Throughput Spectrograph at the 4 m ground-based Southern Astrophysical Research Telescope,covering the wavelength range502-9...We report the transit observations of the ultra-hot Jupiter WASP-121b using the Goodman High Throughput Spectrograph at the 4 m ground-based Southern Astrophysical Research Telescope,covering the wavelength range502-900 nm.By dividing the target and reference star into 19 spectroscopic passbands and applying differential spectrophotometry,we derive spectroscopic transit light curves and fit them using a Gaussian process framework to determine transit depths for every passband.The obtained optical transmission spectrum shows a steep increased slope toward the blue wavelength,which seems to be too steep to be accounted for by Rayleigh scattering alone.We note that the transmission spectrum from this work and other works differ obviously from each other,which was pointed out previously by Wilson et al.as evidence for temporal atmospheric variation.We perform a free chemistry retrieval analysis on the optical transmission spectra from this work and the literature HST/WFC3 NIR spectrum.We determine TiO,VO and H_(2)O with abundances of-5.95_(-0.42)^(+0.47)dex,-6.72_(-1.79)^(+0.51)dex and-4.13_(-0.46)^(+0.63)dex,respectively.We compare the abundances of all three of these molecules derived from this work and previous works,and find that they are not consistent with each other,indicating the chemical compositions of the terminator region may change over long timescales.Future multi-epoch and high-precision transit observations are required to further confirm this phenomenon.We note that when combining the transmission spectra in the optical and in NIR in retrieval analysis,the abundances of V and VO,the NIR-to-optical offset and the cloud deck pressure may be coupled with each other.展开更多
It is commonly believed that the atmosphere is decoupled from the solid Earth.Thus,it is difficult for the seismic wave energy inside the Earth to propagate into the atmosphere,and atmospheric pressure wave signals ex...It is commonly believed that the atmosphere is decoupled from the solid Earth.Thus,it is difficult for the seismic wave energy inside the Earth to propagate into the atmosphere,and atmospheric pressure wave signals excited by earthquakes are unlikely to exist in atmospheric observations.An increasing number of studies have shown that earthquakes,volcanoes,and tsunamis can perturb the Earth's atmosphere due to various coupling effects.However,the observations mainly focus on acoustic waves with periods of less than 10 min and inertial gravity waves with periods of greater than 1 h.There are almost no clear observations of gravity waves that coincide with observations of low-frequency signals of the Earth's free oscillation frequency band within 1 h.This paper investigates atmospheric gravity wave signals within1 h of surface-atmosphere observations using the periodogram method based on seismometer and microbarometer observations from the global seismic network before and after the July 29,2021 M_(w)8.2 Alaska earthquake in the United States.The numerical results show that the atmospheric gravity wave signals with frequencies similar to those of the Earth's free oscillations _(0)S_(2) and _(0)T_(2) can be detected in the microbaro meter observations.The results con firm the existence of atmospheric gravity waves,indicating that the atmosphere and the solid Earth are not decoupled within this frequency band and that seismic wave energy excited by earthquakes can propagate from the interior of the Earth to the atmosphere and enhance the atmospheric gravity wave signals within 1 h.展开更多
BACKGROUND Constipation,a highly prevalent functional gastrointestinal disorder,induces a significant burden on the quality of patients'life and is associated with substantial healthcare expenditures.Therefore,ide...BACKGROUND Constipation,a highly prevalent functional gastrointestinal disorder,induces a significant burden on the quality of patients'life and is associated with substantial healthcare expenditures.Therefore,identifying efficient therapeutic modalities for constipation is of paramount importance.Oxidative stress is a pivotal contributor to colonic dysmotility and is the underlying pathology responsible for constipation symptoms.Consequently,we postulate that hydrogen therapy,an emerging and promising intervention,can serve as a safe and efficacious treatment for constipation.AIM To determine whether hydrogen-rich water(HRW)alleviates constipation and its potential mechanism.METHODS Constipation models were established by orally loperamide to Sprague-Dawley rats.Rats freely consumed HRW,and were recorded their 24 h total stool weight,fecal water content,and charcoal propulsion rate.Fecal samples were subjected to 16S rDNA gene sequencing.Serum non-targeted metabolomic analysis,malondialdehyde,and superoxide dismutase levels were determined.Colonic tissues were stained with hematoxylin and eosin,Alcian blue-periodic acid-Schiff,reactive oxygen species(ROS)immunofluorescence,and immunohistochemistry for cell growth factor receptor kit(c-kit),PGP 9.5,sirtuin1(SIRT1),nuclear factor-erythroid-2-related factor 2(Nrf2),and heme oxygenase-1(HO-1).Quantitative real-time PCR and western blot analysis were conducted to determine the expression level of SIRT1,Nrf2 and HO-1.A rescue experiment was conducted by intraperitoneally injecting the SIRT1 inhibitor,EX527,into constipated rats.NCM460 cells were induced with H2O2 and treated with the metabolites to evaluate ROS and SIRT1 expression.RESULTS HRW alleviated constipation symptoms by improving the total amount of stool over 24 h,fecal water content,charcoal propulsion rate,thickness of the intestinal mucus layer,c-kit expression,and the number of intestinal neurons.HRW modulated intestinal microbiota imbalance and abnormalities in serum metabolism.HRW could also reduce intestinal oxidative stress through the SIRT1/Nrf2/HO-1 signaling pathway.This regulatory effect on oxidative stress was confirmed via an intraperitoneal injection of a SIRT1 inhibitor to constipated rats.The serum metabolites,β-leucine(β-Leu)and traumatic acid,were also found to attenuate H2O2-induced oxidative stress in NCM460 cells by up-regulating SIRT1.CONCLUSION HRW attenuates constipation-associated intestinal oxidative stress via SIRT1/Nrf2/HO-1 signaling pathway,modulating gut microbiota and serum metabolites.β-Leu and traumatic acid are potential metabolites that upregulate SIRT1 expression and reduce oxidative stress.展开更多
A LES model is proposed to predict the dispersion of particles in the atmosphere in the context of Chemical,Biological,Radiological and Nuclear(CBRN)applications.The code relies on the Finite Element Method(FEM)for bo...A LES model is proposed to predict the dispersion of particles in the atmosphere in the context of Chemical,Biological,Radiological and Nuclear(CBRN)applications.The code relies on the Finite Element Method(FEM)for both the fluid and the dispersed solid phases.Starting from the Navier-Stokes equations and a general description of the FEM strategy,the Streamline Upwind Petrov-Galerkin(SUPG)method is formulated putting some emphasis on the related assembly matrix and stabilization coefficients.Then,the Variational Multiscale Method(VMS)is presented together with a detailed illustration of its algorithm and hierarchy of computational steps.It is demonstrated that the VMS can be considered as a more general version of the SUPG method.The final part of the work is used to assess the reliability of the implemented predictor/multicorrector solution strategy.展开更多
The article is devoted to the discussion of the possibilities of approbation of one of the probabilistic methods of verification of evaluation works-the minimax method or the method of establishing the minimum risk of...The article is devoted to the discussion of the possibilities of approbation of one of the probabilistic methods of verification of evaluation works-the minimax method or the method of establishing the minimum risk of making erroneous diagnoses of the instability of the planetary boundary layer of air.Within the framework of this study,the task of probabilistic forecasting of diagnostic parameters and their combinations,leading in their totality to the formation of an unstable state of the planetary boundary layer of the atmosphere,was carried out.It is this state that,as shown by previous studies,a priori contribution to the development of a number of weather phenomena dangerous for society(squalls,hail,heavy rains,etc.).The results of applying the minimax method made it possible to identify a number of parameters,such as the intensity of circulation,the activity of the Earth’s magnetosphere,and the components of the geostrophic wind velocity,the combination of which led to the development of instability.In the future,it is possible to further expand the number of diagnosed parameters to identify more sensitive elements.In this sense,the minimax method,the usefulness of which is shown in this study,can be considered as one of the preparatory steps for the subsequent more detailed method for forecasting individual hazardous weather phenomena.展开更多
A previously developed hybrid coupled model(HCM)is composed of an intermediate tropical Pacific Ocean model and a global atmospheric general circulation model(AGCM),denoted as HCMAGCM.In this study,different El Ni...A previously developed hybrid coupled model(HCM)is composed of an intermediate tropical Pacific Ocean model and a global atmospheric general circulation model(AGCM),denoted as HCMAGCM.In this study,different El Niño flavors,namely the Eastern-Pacific(EP)and Central-Pacific(CP)types,and the associated global atmospheric teleconnections are examined in a 1000-yr control simulation of the HCMAGCM.The HCMAGCM indicates profoundly different characteristics among EP and CP El Niño events in terms of related oceanic and atmospheric variables in the tropical Pacific,including the amplitude and spatial patterns of sea surface temperature(SST),zonal wind stress,and precipitation anomalies.An SST budget analysis indicates that the thermocline feedback and zonal advective feedback dominantly contribute to the growth of EP and CP El Niño events,respectively.Corresponding to the shifts in the tropical rainfall and deep convection during EP and CP El Niño events,the model also reproduces the differences in the extratropical atmospheric responses during the boreal winter.In particular,the EP El Niño tends to be dominant in exciting a poleward wave train pattern to the Northern Hemisphere,while the CP El Niño tends to preferably produce a wave train similar to the Pacific North American(PNA)pattern.As a result,different climatic impacts exist in North American regions,with a warm-north and cold-south pattern during an EP El Niño and a warm-northeast and cold-southwest pattern during a CP El Niño,respectively.This modeling result highlights the importance of internal natural processes within the tropical Pacific as they relate to the genesis of ENSO diversity because the active ocean–atmosphere coupling is allowed only in the tropical Pacific within the framework of the HCMAGCM.展开更多
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences,grant No.XDB 41000000National Natural Science Foundation of China(NSFC,Grant No.12288102)+4 种基金support of the National Natural Science Foundation of China(NSFC,Grant No.11973082)support of the National Natural Science Foundation of China(NSFC,Grant No.42305136)supported by the National Key R&D Program of China(Grant No.2021YFA1600400/2021YFA1600402)Natural Science Foundation of Yunnan Province(No.202201AT070158)the International Centre of Supernovae,Yunnan Key Laboratory(No.202302AN360001)。
文摘Observations of transmission spectra reveal that hot Jupiters and Neptunes are likely to possess escaping atmospheres driven by stellar radiation.Numerous models predict that magnetic fields may exert significant influences on the atmospheres of hot planets.Generally,the escaping atmospheres are not entirely ionized,and magnetic fields only directly affect the escape of ionized components within them.Considering the chemical reactions between ionized components and neutral atoms,as well as collision processes,magnetic fields indirectly impact the escape of neutral atoms,thereby influencing the detection signals of planetary atmospheres in transmission spectra.In order to simulate this process,we developed a magnetohydrodynamic multi-fluid model based on MHD code PLUTO.As an initial exploration,we investigated the impact of magnetic fields on the decoupling of H^(+)and H in the escaping atmosphere of the hot Neptune GJ436b.Due to the strong resonant interactions between H and H^(+),the coupling between them is tight even if the magnetic field is strong.Of course,alternatively,our work also suggests that merging H and H^(+)into a single flow can be a reasonable assumption in MHD simulations of escaping atmospheres.However,our simulation results indicate that under the influence of magnetic fields,there are noticeable regional differences in the decoupling of H^(+)and H.With the increase of magnetic field strength,the degree of decoupling also increases.For heavier particles such as O,the decoupling between O and H^(+)is more pronounced.Our findings provide important insights for future studies on the decoupling processes of heavy atoms in the escaping atmospheres of hot Jupiters and hot Neptunes under the influence of magnetic fields.
文摘Appropriate physical exercise has a positive impact on adolescents’physical and mental health,but there is a serious lack of physical exercise among Chinese adolescents.How to shape their exercise behavior(EB)has become an important task in promoting their development.A questionnaire survey was conducted using stratified cluster random sampling on three middle schools by class in Zhejiang Province,China to investigate the impact of exercise atmosphere(EA)on adolescents’exercise behavior and the mediating role of exercise identity(EI)and exercise habit(EH).806 adolescents were investigated by the Exercise Atmosphere Scale(EAS),Exercise-Identity Scale(EIS),Self-Report Habit Index(SRHI),and Physical Activity Rating Scale(PARS-3).The results show that:There is a significant positive correlation between each two of exercise atmosphere,exercise identity,exercise habit,and exercise behavior(p<0.05).Exercise atmosphere could not only directly affect adolescents’physical exercise behavior but can also indirectly affect their physical exercise behavior through the mediating effect of exercise identity and exercise habit,involving three mediating pathways,namely,the mediating path through exercise identity,the mediating pathway through exercise habit and the chain mediating pathway through exercise identity and exercise habit.The direct effect of exercise atmosphere on exercise behavior was 0.459(p<0.01),accounting for 62.62% of the total effect of 0.733,and its indirect effect was 0.274,accounting for 37.28% of the total effect.To a certain extent,the mediating effect model reveals the mechanism of exercise atmosphere affecting exercise behavior and has a certain reference value for promoting adolescents’exercise behavior.We should start by creating an exercise atmosphere,cultivating exercise identity,and enhancing exercise habits to help teenagers form active physical exercise behaviors.
基金supported by the Qingdao Postdoctoral Program Funding(QDBSH20220202045)Shandong provincial Natural Science Foundation(ZR2021ME049,ZR2022ME176)+1 种基金National Natural Science Foundation of China(22078176)Taishan Industrial Experts Program(TSCX202306135).
文摘In this study,the impact of different reaction times on the preparation of powdered activated carbon(PAC)using a one-step rapid activation method under flue gas atmosphere is investigated,and the underlying reaction mechanism is summarized.Results indicate that the reaction process of this method can be divided into three stages:stage I is the rapid release of volatiles and the rapid consumption of O_(2),primarily occurring within a reaction time range of 0-0.5 s;stage II is mainly the continuous release and diffusion of volatiles,which is the carbonization and activation coupling reaction stage,and the carbonization process is the main in this stage.This stage mainly occurs at the reaction time range of 0.5 -2.0 s when SL-coal is used as material,and that is 0.5-3.0 s when JJ-coal is used as material;stage III is mainly the activation stage,during which activated components diffuse to both the surface and interior of particles.This stage mainly involves the reaction stage of CO_(2)and H2O(g)activation,and it mainly occurs at the reaction time range of 2.0-4.0 s when SL-coal is used as material,and that is 3.0-4.0 s when JJ-coal is used as material.Besides,the main function of the first two stages is to provide more diffusion channels and contact surfaces/activation sites for the diffusion and activation of the activated components in the third stage.Mastering the reaction mechanism would serve as a crucial reference and foundation for designing the structure,size of the reactor,and optimal positioning of the activator nozzle in PAC preparation.
基金supported by the Zhijiang Youth Special Project entitled“Cross-Cultural Examination of National Identity and Discourse Formation in Chinese Short Video Content” (Project No.:24ZJQN026Y)a philosophy and social sciences project funded by Zhejiang province。
文摘In an era of scene-based consumption,the essence of operating a bookstore lies in accepting and enabling the bookstore to play its role as a cultural medium for browsing and appreciating books,which in turn fosters the development of a distinctive bookstore culture.This new type of consumption context has led to an evolution in the book-reading culture in physical bookstores that is characterized by a shift from a paradigm of passive reading to one where the emphasis is on interactive viewing.This transition has laid the foundation for the creation of cultural atmospheres in bookstores,and it highlights the visual interactions that now exist between readers and books as well as with other related cultural industries.The dominant and fundamental logic behind this process is symbiosis,experience,aesthetics,immersion,and creativity.However,when a form of culture that focuses on consumption-oriented browsing begins to overshadow knowledge acquisition during the process of book reading,the cultural essence of bookstores is likely to be diminished.Therefore,the cultural essence within the scene-based consumption context should be enhanced by creating innovative viewing activities that showcase the cultural and emotional implications inherent in the scene itself,and thus help to align the identity of the bookstore with its in-situ cultural space.
基金supported by Central Public-Interest Scientific Institution Basal Research Fund,CAFS(2023TD74,2023TD78)the Earmarked Fund for CARS-47(CARS-47)+2 种基金Guangdong Provincial Science and Technology Plan Project(2023B0202010015)Central Public-Interest Scientific Institution Basal Research Fund,CAFS(Sanya Yazhou Bay Science and Technology City(SKJC-2020-02-013))Special Funds for Promoting Economic Development in Guangdong Province(For Modern Fishery)(YueNong 2019B14).
文摘Here,we aimed to study the changes in proteome of golden pompano fillets during post-mortem storage.Tandem mass tags(TMT)-labeled quantitative proteomic strategy was applied to investigate the relationships between protein changes and quality characteristics of modified atmosphere packaging(MAP)fillets during superchilling(-3°C)storage.Scanning electron microscopy was used to show that the muscle histology microstructure of fillets was damaged to varying degrees,and low-field nuclear magnetic resonance was used to find that the immobilized water and free water in the muscle of fillets changed significantly.Total sulfhydryl content,TCA-soluble peptides and Ca2+-ATPase activity also showed that the fillet protein had a deterioration by oxidation and denaturation.The Fresh(FS),MAP,and air packaging(AP)groups were set.Total of 150 proteins were identified as differential abundant proteins(DAPs)in MAP/FS,while 209 DAPs were in AP/FS group.The KEGG pathway analysis indicated that most DAPs were involved in binding proteins and protein turnover.Correlation analysis found that 52 DAPs were correlated with quality traits.Among them,8 highly correlated DAPs are expected to be used as potential quality markers for protein oxidation and water-holding capacity.These results provide a further understanding of the muscle deterioration mechanism of packaging golden pompano fillets during superchilling.
基金supported by a grant from National Program for Research of the National Association of Technical Universities-GNAC ARUT 2023.
文摘The present work aims to investigate the effect of heating temperature(400,600 and 800°C)and inoculating elements(Ca,Ca-Ba,Ca-RE)on oxidation behavior of ductile irons containing 5.25%Si and 4.8%Si-2.3%Mo in dry air and combustion gas containing water vapour(natural gas burning).The oxidation is influenced by the gas atmosphere type,the iron alloying system,and the inoculating elements depending on the heating temperature.The weight gain increases from 0.001%-0.1%(400°C)to 0.05%-0.70%(600°C)and up to 0.10%-2.15%(800°C).No particular effects of the considered influencing factors are found when heating at 400°C,while at 600°C,mainly the oxidation gas atmosphere type shows a visible influence.At the highest heating temperature of 800°C,a limited increase of the weight gain is found for dry air atmosphere(up to 0.25%),but it drastically increases for combustion atmospheres(0.65%-2.15%).The water vapour presence in the combustion atmosphere is an important oxidising factor at 600-800°C.The alloying system appears to influence the oxidation behavior mainly at a heating temperature of 800°C in the combustion atmosphere,as evidenced by the lower weight gain in 5.25%silicon cast iron.Positive effects of inoculating elements increase with the heating temperature,with Ca and Ba-FeSi inoculation generally showing better performance.Irons inoculated with CaRE-FeSi exhibit a higher degree of oxidation.These results are in good relationship with the previous reported data:Ca-Ba-inoculation system appears to be better than simple Ca for improving the graphite parameters,while RE-bearing inoculant negatively affects the compactness degree of graphite particles in high-Si ductile irons.As the lower compactness degree is typical for graphite nodules in high-Si ductile irons,which negatively affects the oxidation resistance,it is necessary to employ specific metallurgical treatments to improve nodule quality.Inoculation,in particular,is a potential method to achieve this improvement.
基金supported by the National Key Technologies R&D Program of China[grant number 2022YFC3002803]the National Science Fund for Distinguished Young Scholars[grant number 41925021].
基金financially supported by China Agriculture Research System (Beijing, China, CARS-41-Z06)Nanjing Professor Huang Food Technology Co., Ltd.
文摘This study mainly monitored the dominant bacterial populations and identified the spoilage-related microorganisms of braised chicken meat stored under different CO_(2)-modified atmosphere packaging(MAP)during refrigerated storage using a culture-dependent method and 16S rDNA identification.The quality changes and shelf life of the meat were also measured.The growth rate of total viable count(TVC)in braised chicken was slower with an increase of CO_(2) content in MAP,which also occurred in the remaining bacterial species monitored(lactic acid bacteria,Pseudomonas spp.,Brochothrix thermosphacta).The MAP exerted beneficial effects on the quality of braised chicken,as demonstrated by retarding the production of total volatile basic nitrogen(TVB-N)and delaying lipid oxidation(TBARS test).A total of 14 isolates were identified from braised chickens with different packaging at the end of storage,these included P.fragi(6 isolates),P.psychrophila(2 isolates),Enterococcus faecalis(3 isolates),B.thermosphacta(2 isolates),Staphylococcus equorum(1 isolate).
基金financially supported by the National Key Research and Development Program of China(No.2020YFC1909803)the Basic Science Center Project for the National Natural Science Foundation of China(No.72088101)the Graduate Research and Innovative Project of Central South University(No.506021739)。
文摘To realize the comprehensive utilization of ludwigite ore,an integrated and efficient route for the boron and iron separation was proposed in this work,which via soda-ash roasting under CO–CO_(2)–N_(2) atmosphere followed by grind-leaching,magnetic separation,and CO_(2) carbonation.The effects of roasting temperature,roasting time,CO/(CO+CO_(2))composition,and Na_(2)CO_(3) dosage on the boron and iron separation indices were primarily investigated.Under the optimized conditions of the roasting temperature of 850℃,roasting time of 60 min,soda ash dosage of 20 wt%,and CO/(CO+CO_(2)) of 10 vol%,92%of boron was leached during wet grinding,and 88.6%of iron was recovered during the magnetic separation and magnetic concentrate with a total iron content of 61.51 wt%.Raman spectra and^(11)B NMR results indicated that boron exists asB(OH)_(4)^(-) in the leachate,from which high-purity borax pentahydrate could be prepared by CO_(2) carbonation.
基金the National Key R&D Program of China(No.2021YFB3701705).
文摘This work constructed a machine learning(ML)model to predict the atmospheric corrosion rate of low-alloy steels(LAS).The material properties of LAS,environmental factors,and exposure time were used as the input,while the corrosion rate as the output.6 dif-ferent ML algorithms were used to construct the proposed model.Through optimization and filtering,the eXtreme gradient boosting(XG-Boost)model exhibited good corrosion rate prediction accuracy.The features of material properties were then transformed into atomic and physical features using the proposed property transformation approach,and the dominant descriptors that affected the corrosion rate were filtered using the recursive feature elimination(RFE)as well as XGBoost methods.The established ML models exhibited better predic-tion performance and generalization ability via property transformation descriptors.In addition,the SHapley additive exPlanations(SHAP)method was applied to analyze the relationship between the descriptors and corrosion rate.The results showed that the property transformation model could effectively help with analyzing the corrosion behavior,thereby significantly improving the generalization ability of corrosion rate prediction models.
基金supported by the Open Research Fund of TPESER(Grant No.TPESER202205)the Second Tibetan Plateau Scientific Expedition and Research Program(Grant No.2019QZKK0101)。
文摘The spring atmospheric heat source(AHS)over the Tibetan Plateau(TP)has been suggested to affect the Asian summer monsoon and summer precipitation over South China.However,its influence on the summer precipitation in Northeast China(NEC)remains unknown.The connection between spring TP AHS and subsequent summer precipitation over NEC from 1961 to 2020 is analyzed in this study.Results illustrate that stronger spring TP AHS can enhance subsequent summer NEC precipitation,and higher soil moisture in the Yellow River Valley-North China region(YRVNC)acts as a bridge.During spring,the strong TP AHS could strengthen the transportation of water vapor to East China and lead to excessive rainfall in the YRVNC.Thus,soil moisture increases,which regulates local thermal conditions by decreasing local surface skin temperature and sensible heat.Owing to the memory of soil moisture,the lower spring sensible heat over the YRVNC can last until mid-summer,decrease the land–sea thermal contrast,and weaken the southerly winds over the East Asia–western Pacific region and convective activities over the South China Sea and tropical western Pacific.This modulates the East Asia–Pacific teleconnection pattern,which leads to a cyclonic anomaly and excessive summer precipitation over NEC.
基金supported by the National Natural Science Foundation of China (Grant no. 42006190)the Chinese Polar Environmental Comprehensive Investigation and Assessment Programs (Grant no. CHINARE2010-2020)+2 种基金the Chinese International Cooperation Projects (Grant no. 2009DFA22920) from the Ministry of Science and Technologythe Chinese Arctic and Antarctic Administrationthe Third Institute of Oceanography of MNR for their support
文摘Microplastics,plastic particles smaller than 5 mm in size,are a growing source of environmental pollution.Microplastic pollution has been observed in situ in the remote Arctic,where it has been found in the land,sea,cryosphere,and atmosphere.This review summarizes the sample pretreatment techniques and analytical methods commonly used in microplastic research,as well as the pollution status of microplastics in the Arctic,their sources,and their effects on the environment.In the Arctic,the size distribution of microplastics is more inclined to small-scale aggregation,the shape of microplastics is mostly fibrous,with the proportion of fibers often accounting for more than 70%.There are marked differences among studies in terms of abundance and polymer composition,but polyester is generally dominant in seawater.Many microplastic particles are transported to the Arctic by ocean currents and rivers,but atmospheric transport and deposition are slowly being recognized as an important transport route.Sea ice is particularly important for the temporary storage,transport,and release of Arctic microplastics.The average storage of microplastics in sea ice was estimated to be approximately 6.1×108 items.Given their properties,microplastics can affect glacier melting,sea surface temperature changes,and even the carbon cycle.Urgent measures must be taken to improve research standards and overcome sampling difficulties in the Arctic region to achieve time continuity and large-scale distribution patterns of Arctic microplastics.
基金supported by the Chinese-Norwegian Collaboration Projects within Climate Systems jointly funded by the National Key Research and Development Program of China (Grant No.2022YFE0106800)the Research Council of Norway funded project MAPARC (Grant No.328943)+2 种基金the support from the Research Council of Norway funded project BASIC (Grant No.325440)the Horizon 2020 project APPLICATE (Grant No.727862)High-performance computing and storage resources were performed on resources provided by Sigma2 - the National Infrastructure for High-Performance Computing and Data Storage in Norway (through projects NS8121K,NN8121K,NN2345K,NS2345K,NS9560K,NS9252K,and NS9034K)。
文摘To quantify the relative contributions of Arctic sea ice and unforced atmospheric internal variability to the “warm Arctic, cold East Asia”(WACE) teleconnection, this study analyses three sets of large-ensemble simulations carried out by the Norwegian Earth System Model with a coupled atmosphere–land surface model, forced by seasonal sea ice conditions from preindustrial, present-day, and future periods. Each ensemble member within the same set uses the same forcing but with small perturbations to the atmospheric initial state. Hence, the difference between the present-day(or future) ensemble mean and the preindustrial ensemble mean provides the ice-loss-induced response, while the difference of the individual members within the present-day(or future) set is the effect of atmospheric internal variability. Results indicate that both present-day and future sea ice loss can force a negative phase of the Arctic Oscillation with a WACE pattern in winter. The magnitude of ice-induced Arctic warming is over four(ten) times larger than the ice-induced East Asian cooling in the present-day(future) experiment;the latter having a magnitude that is about 30% of the observed cooling. Sea ice loss contributes about 60%(80%) to the Arctic winter warming in the present-day(future) experiment. Atmospheric internal variability can also induce a WACE pattern with comparable magnitudes between the Arctic and East Asia. Ice-lossinduced East Asian cooling can easily be masked by atmospheric internal variability effects because random atmospheric internal variability may induce a larger magnitude warming. The observed WACE pattern occurs as a result of both Arctic sea ice loss and atmospheric internal variability, with the former dominating Arctic warming and the latter dominating East Asian cooling.
基金supported by the National Natural Science Foundation of China (Grant Nos. 12274373 and 12004341)the Open Project of Inner Mongolia Key Laboratory of High-pressure Phase Functional Materials,Chifeng University (Grant No. cfxygy202301)+1 种基金the Science and Technology Project of Xilinguole Province (Grant No. 202209)the Natural Science Foundation of Henan Province (Grant No. 242300421155)。
文摘The regulating nitrogen content of diamond in a hydrogen-rich high-temperature and high-pressure(HPHT) growth environment was systematically investigated in this work by developing three growth systems,namely, "FeNi+Ti", "FeNi+G_(3)N_(6)H_(6)",and "FeNi+Ti+C_(3)N_(6)H_(6)".Optical microscopy,infrared spectroscopy,and photoluminescence(PL)spectroscopy measurements were conducted to analyze the spectroscopic characteristics of diamonds grown in these three systems.From our analysis,it was demonstrated that the presence of hydrogen in the sp^(3) hybrid C-H does not directly affect the color of the diamond and facilitates the increase of the nitrogen-vacancy(NV) center concentration in a highnitrogen-content diamond.In addition,titanium plays an important role in nitrogen removal,while its impact on hydrogen doping within the diamond lattice is insignificant.Most importantly,by regulating the ratio of nitrogen impurities that coexist in the nitrogen and hydrogen HPHT environment,the production of hydrogenous Ⅱa-type diamond,hydrogenous Ib-type diamond,and hydrogenous high-nitrogen-type diamonds was achieved with a nitrogen content of less than 1 ppm to 1600 ppm.
基金supported by the National Key R&D Program of China Nos.2019YFA0405102 and 2019YFA0405502the National Natural Science Foundation of China(NSFC,Grant Nos.42075123,62127901,11988101,42005098,and 12073044)+1 种基金supported by the China Manned Space Project with No.CMS-CSST-2021-B12supported by the Chinese Academy of Sciences(CAS),through a grant to the CAS South America Center for Astronomy(CASSACA)in Santiago,Chile。
文摘We report the transit observations of the ultra-hot Jupiter WASP-121b using the Goodman High Throughput Spectrograph at the 4 m ground-based Southern Astrophysical Research Telescope,covering the wavelength range502-900 nm.By dividing the target and reference star into 19 spectroscopic passbands and applying differential spectrophotometry,we derive spectroscopic transit light curves and fit them using a Gaussian process framework to determine transit depths for every passband.The obtained optical transmission spectrum shows a steep increased slope toward the blue wavelength,which seems to be too steep to be accounted for by Rayleigh scattering alone.We note that the transmission spectrum from this work and other works differ obviously from each other,which was pointed out previously by Wilson et al.as evidence for temporal atmospheric variation.We perform a free chemistry retrieval analysis on the optical transmission spectra from this work and the literature HST/WFC3 NIR spectrum.We determine TiO,VO and H_(2)O with abundances of-5.95_(-0.42)^(+0.47)dex,-6.72_(-1.79)^(+0.51)dex and-4.13_(-0.46)^(+0.63)dex,respectively.We compare the abundances of all three of these molecules derived from this work and previous works,and find that they are not consistent with each other,indicating the chemical compositions of the terminator region may change over long timescales.Future multi-epoch and high-precision transit observations are required to further confirm this phenomenon.We note that when combining the transmission spectra in the optical and in NIR in retrieval analysis,the abundances of V and VO,the NIR-to-optical offset and the cloud deck pressure may be coupled with each other.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB41000000)the National Natural Science Foundation of China(Grant No.42174101,41974023)+1 种基金the Open Fund of Hubei Luojia Laboratory(Grant No.S22H640201)(Germany)The Offshore International Science and Technology Cooperation Center of Frontier Technology of Geodesy。
文摘It is commonly believed that the atmosphere is decoupled from the solid Earth.Thus,it is difficult for the seismic wave energy inside the Earth to propagate into the atmosphere,and atmospheric pressure wave signals excited by earthquakes are unlikely to exist in atmospheric observations.An increasing number of studies have shown that earthquakes,volcanoes,and tsunamis can perturb the Earth's atmosphere due to various coupling effects.However,the observations mainly focus on acoustic waves with periods of less than 10 min and inertial gravity waves with periods of greater than 1 h.There are almost no clear observations of gravity waves that coincide with observations of low-frequency signals of the Earth's free oscillation frequency band within 1 h.This paper investigates atmospheric gravity wave signals within1 h of surface-atmosphere observations using the periodogram method based on seismometer and microbarometer observations from the global seismic network before and after the July 29,2021 M_(w)8.2 Alaska earthquake in the United States.The numerical results show that the atmospheric gravity wave signals with frequencies similar to those of the Earth's free oscillations _(0)S_(2) and _(0)T_(2) can be detected in the microbaro meter observations.The results con firm the existence of atmospheric gravity waves,indicating that the atmosphere and the solid Earth are not decoupled within this frequency band and that seismic wave energy excited by earthquakes can propagate from the interior of the Earth to the atmosphere and enhance the atmospheric gravity wave signals within 1 h.
基金Supported by National Natural Science Foundation of China,No.82374449China Postdoctoral Science Foundation,No.2023M731782+1 种基金Jiangsu Funding Program for Excellent Postdoctoral Talent,No.2022ZB806Jiangsu Province Postgraduate Scientific Research and Innovation Plan,No.KYCX23_2136.
文摘BACKGROUND Constipation,a highly prevalent functional gastrointestinal disorder,induces a significant burden on the quality of patients'life and is associated with substantial healthcare expenditures.Therefore,identifying efficient therapeutic modalities for constipation is of paramount importance.Oxidative stress is a pivotal contributor to colonic dysmotility and is the underlying pathology responsible for constipation symptoms.Consequently,we postulate that hydrogen therapy,an emerging and promising intervention,can serve as a safe and efficacious treatment for constipation.AIM To determine whether hydrogen-rich water(HRW)alleviates constipation and its potential mechanism.METHODS Constipation models were established by orally loperamide to Sprague-Dawley rats.Rats freely consumed HRW,and were recorded their 24 h total stool weight,fecal water content,and charcoal propulsion rate.Fecal samples were subjected to 16S rDNA gene sequencing.Serum non-targeted metabolomic analysis,malondialdehyde,and superoxide dismutase levels were determined.Colonic tissues were stained with hematoxylin and eosin,Alcian blue-periodic acid-Schiff,reactive oxygen species(ROS)immunofluorescence,and immunohistochemistry for cell growth factor receptor kit(c-kit),PGP 9.5,sirtuin1(SIRT1),nuclear factor-erythroid-2-related factor 2(Nrf2),and heme oxygenase-1(HO-1).Quantitative real-time PCR and western blot analysis were conducted to determine the expression level of SIRT1,Nrf2 and HO-1.A rescue experiment was conducted by intraperitoneally injecting the SIRT1 inhibitor,EX527,into constipated rats.NCM460 cells were induced with H2O2 and treated with the metabolites to evaluate ROS and SIRT1 expression.RESULTS HRW alleviated constipation symptoms by improving the total amount of stool over 24 h,fecal water content,charcoal propulsion rate,thickness of the intestinal mucus layer,c-kit expression,and the number of intestinal neurons.HRW modulated intestinal microbiota imbalance and abnormalities in serum metabolism.HRW could also reduce intestinal oxidative stress through the SIRT1/Nrf2/HO-1 signaling pathway.This regulatory effect on oxidative stress was confirmed via an intraperitoneal injection of a SIRT1 inhibitor to constipated rats.The serum metabolites,β-leucine(β-Leu)and traumatic acid,were also found to attenuate H2O2-induced oxidative stress in NCM460 cells by up-regulating SIRT1.CONCLUSION HRW attenuates constipation-associated intestinal oxidative stress via SIRT1/Nrf2/HO-1 signaling pathway,modulating gut microbiota and serum metabolites.β-Leu and traumatic acid are potential metabolites that upregulate SIRT1 expression and reduce oxidative stress.
基金The authors received the funding of the Royal Higher Institute for Defence(MSP16-06).
文摘A LES model is proposed to predict the dispersion of particles in the atmosphere in the context of Chemical,Biological,Radiological and Nuclear(CBRN)applications.The code relies on the Finite Element Method(FEM)for both the fluid and the dispersed solid phases.Starting from the Navier-Stokes equations and a general description of the FEM strategy,the Streamline Upwind Petrov-Galerkin(SUPG)method is formulated putting some emphasis on the related assembly matrix and stabilization coefficients.Then,the Variational Multiscale Method(VMS)is presented together with a detailed illustration of its algorithm and hierarchy of computational steps.It is demonstrated that the VMS can be considered as a more general version of the SUPG method.The final part of the work is used to assess the reliability of the implemented predictor/multicorrector solution strategy.
文摘The article is devoted to the discussion of the possibilities of approbation of one of the probabilistic methods of verification of evaluation works-the minimax method or the method of establishing the minimum risk of making erroneous diagnoses of the instability of the planetary boundary layer of air.Within the framework of this study,the task of probabilistic forecasting of diagnostic parameters and their combinations,leading in their totality to the formation of an unstable state of the planetary boundary layer of the atmosphere,was carried out.It is this state that,as shown by previous studies,a priori contribution to the development of a number of weather phenomena dangerous for society(squalls,hail,heavy rains,etc.).The results of applying the minimax method made it possible to identify a number of parameters,such as the intensity of circulation,the activity of the Earth’s magnetosphere,and the components of the geostrophic wind velocity,the combination of which led to the development of instability.In the future,it is possible to further expand the number of diagnosed parameters to identify more sensitive elements.In this sense,the minimax method,the usefulness of which is shown in this study,can be considered as one of the preparatory steps for the subsequent more detailed method for forecasting individual hazardous weather phenomena.
基金supported by the National Natural Science Foundation of China(NSFCGrant No.42275061)+3 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB40000000)the Laoshan Laboratory(Grant No.LSKJ202202404)the NSFC(Grant No.42030410)the Startup Foundation for Introducing Talent of Nanjing University of Information Science and Technology.
文摘A previously developed hybrid coupled model(HCM)is composed of an intermediate tropical Pacific Ocean model and a global atmospheric general circulation model(AGCM),denoted as HCMAGCM.In this study,different El Niño flavors,namely the Eastern-Pacific(EP)and Central-Pacific(CP)types,and the associated global atmospheric teleconnections are examined in a 1000-yr control simulation of the HCMAGCM.The HCMAGCM indicates profoundly different characteristics among EP and CP El Niño events in terms of related oceanic and atmospheric variables in the tropical Pacific,including the amplitude and spatial patterns of sea surface temperature(SST),zonal wind stress,and precipitation anomalies.An SST budget analysis indicates that the thermocline feedback and zonal advective feedback dominantly contribute to the growth of EP and CP El Niño events,respectively.Corresponding to the shifts in the tropical rainfall and deep convection during EP and CP El Niño events,the model also reproduces the differences in the extratropical atmospheric responses during the boreal winter.In particular,the EP El Niño tends to be dominant in exciting a poleward wave train pattern to the Northern Hemisphere,while the CP El Niño tends to preferably produce a wave train similar to the Pacific North American(PNA)pattern.As a result,different climatic impacts exist in North American regions,with a warm-north and cold-south pattern during an EP El Niño and a warm-northeast and cold-southwest pattern during a CP El Niño,respectively.This modeling result highlights the importance of internal natural processes within the tropical Pacific as they relate to the genesis of ENSO diversity because the active ocean–atmosphere coupling is allowed only in the tropical Pacific within the framework of the HCMAGCM.
