This study employed integrated multi-omics approaches to elucidate,from the perspective of amino acid metabolism,the adaptive mechanism of Penicillium digitatum under modified atmosphere packaging(MAP)conditions.Compa...This study employed integrated multi-omics approaches to elucidate,from the perspective of amino acid metabolism,the adaptive mechanism of Penicillium digitatum under modified atmosphere packaging(MAP)conditions.Comparative analysis of natural air(Air),controlled atmosphere(CA),and MAP treatments revealed that MAP upregulated the expression of the hercynylcysteine S-oxide synthase(HCSOS),aldehyde dehydrogenase(ALDH),and monoamine oxidase(MAO)genes,thereby enhancing histidine-derived ergothioneine and methionine levels,and subsequently boosting glutathione-mediated redox homeostasis.Meanwhile,MAP induced the expression of the dihydroxyacid dehydratase(DHAD),saccharopine dehydrogenase(SDH),and arginosuccinate lyase(ASL)genes,redirecting valine,lysine,and arginine into the tricarboxylic acid(TCA)cycle to fuel ATP production.MAP also enhanced ASL-mediated arginine degradation and urea cycle activity,reducing arginine accumulation when compared to CA treatment.In contrast,while MAP induced upregulated expression of the pyrroline-5-carboxylate dehydrogenase(P5CDH)and D-amino acid oxidase(DAAO)genes,CA treatment promoted proline accumulation,reflecting stress-specific metabolic flexibility.Collectively,these findings demonstrate that MAP triggers transcriptional reprogramming of amino acid metabolism to coordinate oxidative defense,energy generation,and osmotic balance.By modulating these metabolic pathways and regulatory genes under MAP conditions,fungal adaptability can be disrupted.Hence,this study provides a promising strategy for suppressing green mold development,extending the postharvest shelf life,and improving the quality of fruits and vegetables.展开更多
The IUGG Associations for Atmosphere,Oceans and Cryosphere—IAMAS,IAPSO and IACS—held a Joint Scientific Assembly in Busan,South Korea,from 20 to 25 July 2025.This was the first joint assembly of all three associatio...The IUGG Associations for Atmosphere,Oceans and Cryosphere—IAMAS,IAPSO and IACS—held a Joint Scientific Assembly in Busan,South Korea,from 20 to 25 July 2025.This was the first joint assembly of all three associations since 2009,when they met in Montreal,Canada.It was the first time any of the associations had been hosted in Korea,and it had been two decades since any of them had met in Asia.The choice of Busan as the venue supported high levels of participation and smooth conference operations.The Local Organizing Committee,chaired by Prof.Kyung-Ja Ha of Pusan National University,oversaw the successful organization of the event.The assembly brought together 1725 participants in total,including 1282 researchers and 443 invited participants and individuals involved in side events,exhibitions,media coverage,and volunteer work.Participants came from 46 countries across Asia,Europe,North America,South America,Africa,and Oceania.IAMAS had 736 participants,IAPSO 321,and IACS 225.Survey data from 951 respondents revealed that Early Career Scientists,defined as those within 10 years of receiving their PhD,accounted for approximately 25%of participants.The demographic profile skewed young,with 66%of attendees in their 20s and 30s.The scientific program was organized by Prof.Seon-Ki Park(Chair),the Secretaries General from all three Associations,and the Local Organizing Committee.Reflecting the theme“Our Interconnected Earth,”the scientific program emphasized integrated approaches to climate systems,addressing climate change and environmental challenges through collaborative,transdisciplinary research.展开更多
To address the kinetic constraints inherent in the catalytic combustion of pulverized coal injection under low heating-rate conditions within conventional air atmospheres,a drop tube furnace was utilized to simulate t...To address the kinetic constraints inherent in the catalytic combustion of pulverized coal injection under low heating-rate conditions within conventional air atmospheres,a drop tube furnace was utilized to simulate the catalytic combustion of pulverized coal(PC).The effects of gas composition,oxygen concentration,the type,and the content of catalysts on the combustion reactivity were systematically analyzed.Furthermore,the structural changes of unburned pulverized coal were also examined.Experimental results indicate that as the oxygen concentration increased from 21%to 79%,compared with the O_(2)/N_(2)condition,the increment in the burnout rate of PC under the O_(2)/CO_(2)condition increased from 3%to 23%.After the addition of catalysts,including hematite,metallurgical oil sludge,and light-burnt dolomite(LBD),under the condition of 21%oxygen concentration,the effects of the three catalysts under the O_(2)/CO_(2)condition were superior to those under the O_(2)/N_(2)condition.This trend was reversed under the conditions of 38%and 79%oxygen concentrations.In all atmospheres,the three catalysts can enhance the burnout rate of PC.Among them,LBD exhibits the most favorable effect,and there exists an optimal dosage.Mechanistic analysis through scanning electron microscopy,X-ray diffraction,and N_(2)adsorption-desorption reveals that under 21%O_(2)/79%CO_(2)conditions,high-concentration CO_(2)leads to the formation of pores,and additives accelerate the oxidation of C and the gasification of CO_(2)through oxygen transfer,thereby enhancing the burnout rate of PC.展开更多
Ambient ozone(O_(3))is generated through the reactions of nitrogen oxides and volatile organic compounds(VOCs)in sunlight,and the primary sources of RO_(x)radicals play a very important role in O_(3)photochemistry.How...Ambient ozone(O_(3))is generated through the reactions of nitrogen oxides and volatile organic compounds(VOCs)in sunlight,and the primary sources of RO_(x)radicals play a very important role in O_(3)photochemistry.However,as major precursors of RO_(x)radicals,the systematical evaluation of ClNO_(2),HCHO,and HONO impacts on O_(3)photochemistry remains limited.Here,we utilized the observations of ClNO_(2),HCHO,and HONO conducted in a coastal city of Southeast China during a photochemical O_(3)pollution episode,combined with model simulations to elucidate their impacts on RO_(x)radicals and atmospheric oxidation capacity(AOC),as well as O_(3)formation.Decreased concentrations of ClNO_(2)and HONO were observed after sunrise,while HCHO concentrations peaked in the daytime.HCHO photolysis contributed the largest(∼25%)to RO_(x)radical production around noon,while HONO photolysis(∼47%)dominated RO_(x)radical production in the morning and late afternoon,and VOCs consumed by Cl radical released via ClNO_(2)photolysis was more important(∼10%)in the early morning,similar to their effects on the AOC levels.The results of model simulations indicated that HCHO photolysis greatly enhanced the photochemical formation of O_(3),followed by HONO and ClNO_(2)photolysis.Except for reducing VOCs due to a VOC-limited regime,the impacts of HCHO photolysis as primary RO_(x)sources should be valued to inhibit the intensification of O_(3)pollution.Our study stressed the importance of primary RO_(x)sources for O_(3)photochemistry in coastal regions,provided new insights into elucidating the self-purifying effect of the atmospheric environment.展开更多
The Si_(3)N_(4)-bonded silicon carbide(SiC)bricks in the sloped zone of dry quenching coke ovens support the weight of upper refractory materials and equipment.These bricks endure frequent temperature fluctuations and...The Si_(3)N_(4)-bonded silicon carbide(SiC)bricks in the sloped zone of dry quenching coke ovens support the weight of upper refractory materials and equipment.These bricks endure frequent temperature fluctuations and intense abrasion from coke dust,demanding extremely high performance.After three years of service,an analysis of the Si_(3)N_(4)-bonded SiC bricks revealed that oxidation,which reduces thermal shock resistance,is the primary cause of degradation.In the unused Si_(3)N_(4)-bonded SiC bricks,short columnar β-Si_(3)N_(4) forms an interwoven network around SiC particles and contains a small amount of plate-like Si_(2)N_(2)O.Under the complex N_(2)(84.42 vol.%)-CO_(2)(10.44 vol.%)-CO(4.43 vol.%)-H_(2)(0.56 vol.%)-O_(2)(0.15 vol.%)atmosphere in the dry quenching coke oven,O_(2)(0.15 vol.%)exhibits a stronger oxidizing effect than CO_(2)(10.44 vol.%)and CO(4.43 vol.%),making it the primary oxidizing agent.The short columnarβ-Si_(3)N_(4) is more susceptible to oxidation than the particulate SiC.Based on thermodynamic and kinetic analyses,the chemical stability of the phases in Si_(3)N_(4)-bonded SiC bricks ranks from strongest to weakest as follows:Si_(2)N_(2)O,SiC,Si_(3)N_(4).Future development of Si_(2)N_(2)O-bonded SiC bricks could improve the longevity of refractory materials in the sloped zone of dry quenching coke ovens.展开更多
Internal gravity waves(IGWs)are critical in driving Martian atmospheric motion and phenomena.This study investigates Martian IGWs by using high-resolution data from China’s Tianwen-1 mission and the National Aeronaut...Internal gravity waves(IGWs)are critical in driving Martian atmospheric motion and phenomena.This study investigates Martian IGWs by using high-resolution data from China’s Tianwen-1 mission and the National Aeronautics and Space Administration’s Mars Global Surveyor(MGS)by the radio occultation(RO)technique.Key IGW parameters,such as vertical and horizontal wavelengths,intrinsic frequency,and energy density,are extracted based on vertical temperature profiles from the Martian surface to~50 km altitude.Data reveal that the Martian IGWs are predominantly small-scale waves,with vertical wavelengths between 6 and 13 km and horizontal wavelengths extending to thousands of kilometers.These waves propagate almost vertically and exhibit low intrinsic frequencies close to the inertial frequency,with the characteristic of low-frequency inertial IGWs.Tianwen-1 data indicate stronger IGW activity,higher energy density,and less dissipation than MGS data in the northern hemisphere.Moreover,MGS data in the southern hemisphere show higher buoyancy frequencies and lower vertical wavelengths,suggesting more stable atmospheric conditions conducive to IGW propagation.These extracted IGW characteristics can enhance our understanding of the atmospheric dynamics on Mars and contribute valuable information for parameterization in global circulation models.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
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
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
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
The parachute deployment conditions during the terminal entry phase in Mars landing missions exhibit critical impact on landing precision.In this article,aiming at the requirements of safe parachute deployment and acc...The parachute deployment conditions during the terminal entry phase in Mars landing missions exhibit critical impact on landing precision.In this article,aiming at the requirements of safe parachute deployment and accurate landing,a multidimensional parachute deployment box for determining deployment condition during Mars landing was proposed.First,an extremerange optimization model was established,synthesizing the dynamics and constraints of both parachute descent and powered descent phases.Then,on the basis of the two-dimensional altitude-velocity deployment box,a multi-dimensional parachute deployment box characterized by altitude,velocity,flight-path angle,and extreme range was constructed through the integration of extreme range information.Furthermore,an evaluation index for landing precision was formulated and a deployment control logic was proposed for minimizing landing deviation.Finally,the proposed deployment box was simulated in a Mars landing mission.The results demonstrate that the proposed box effectively satisfies safe deployment and landing precision demands,eliminating the range-to-go error at the terminal of the entry phase.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
In this study, we present an innovative Mars Ionosphere-Thermosphere Model(MITM), which is a time-dependent, threedimensional(3-D) model that comprehensively represents the self-consistently coupled thermosphere and i...In this study, we present an innovative Mars Ionosphere-Thermosphere Model(MITM), which is a time-dependent, threedimensional(3-D) model that comprehensively represents the self-consistently coupled thermosphere and ionosphere of Mars within the altitude range of 70-300 km. The model incorporates an extensive range of parameters, including neutral number densities of CO_(2), CO,O, O_(2), N_(2), NO, N(^(2)D), N(^(4)S), Ar, and He;ion number densities of CO_(2)^(+), CO^(+), O^(+), O_(2)^(+), N_(2)^(+), NO^(+), N^(+) ions, and electrons;neutral temperature;and neutral wind fields. The MITM code employs a high-resolution grid system in a spherical geographical coordinate system, with a horizontal resolution of 5° latitude by 7.5° longitude. This altitude-resolved grid system enables accurate depiction of spatial variations in the Martian thermosphere and ionosphere. To showcase the capabilities of the MITM, we present two simulation cases: one during the equinox and another during the solstice. Both simulations reproduce key features of the Martian thermosphere and ionosphere including the characteristics of horizontal circulation, diurnal variations in chemical composition, and distribution of electron density. The MITM offers a robust framework for understanding the intricate interactions and processes that shape the Mars thermosphere and ionosphere,which are crucial for enhancing our understanding of Martian upper atmosphere and ionosphere.展开更多
文摘This study employed integrated multi-omics approaches to elucidate,from the perspective of amino acid metabolism,the adaptive mechanism of Penicillium digitatum under modified atmosphere packaging(MAP)conditions.Comparative analysis of natural air(Air),controlled atmosphere(CA),and MAP treatments revealed that MAP upregulated the expression of the hercynylcysteine S-oxide synthase(HCSOS),aldehyde dehydrogenase(ALDH),and monoamine oxidase(MAO)genes,thereby enhancing histidine-derived ergothioneine and methionine levels,and subsequently boosting glutathione-mediated redox homeostasis.Meanwhile,MAP induced the expression of the dihydroxyacid dehydratase(DHAD),saccharopine dehydrogenase(SDH),and arginosuccinate lyase(ASL)genes,redirecting valine,lysine,and arginine into the tricarboxylic acid(TCA)cycle to fuel ATP production.MAP also enhanced ASL-mediated arginine degradation and urea cycle activity,reducing arginine accumulation when compared to CA treatment.In contrast,while MAP induced upregulated expression of the pyrroline-5-carboxylate dehydrogenase(P5CDH)and D-amino acid oxidase(DAAO)genes,CA treatment promoted proline accumulation,reflecting stress-specific metabolic flexibility.Collectively,these findings demonstrate that MAP triggers transcriptional reprogramming of amino acid metabolism to coordinate oxidative defense,energy generation,and osmotic balance.By modulating these metabolic pathways and regulatory genes under MAP conditions,fungal adaptability can be disrupted.Hence,this study provides a promising strategy for suppressing green mold development,extending the postharvest shelf life,and improving the quality of fruits and vegetables.
基金support from USA NSF(Grant No.OPP2213875)NASA(Grant No.80NSSC22K1707).
文摘The IUGG Associations for Atmosphere,Oceans and Cryosphere—IAMAS,IAPSO and IACS—held a Joint Scientific Assembly in Busan,South Korea,from 20 to 25 July 2025.This was the first joint assembly of all three associations since 2009,when they met in Montreal,Canada.It was the first time any of the associations had been hosted in Korea,and it had been two decades since any of them had met in Asia.The choice of Busan as the venue supported high levels of participation and smooth conference operations.The Local Organizing Committee,chaired by Prof.Kyung-Ja Ha of Pusan National University,oversaw the successful organization of the event.The assembly brought together 1725 participants in total,including 1282 researchers and 443 invited participants and individuals involved in side events,exhibitions,media coverage,and volunteer work.Participants came from 46 countries across Asia,Europe,North America,South America,Africa,and Oceania.IAMAS had 736 participants,IAPSO 321,and IACS 225.Survey data from 951 respondents revealed that Early Career Scientists,defined as those within 10 years of receiving their PhD,accounted for approximately 25%of participants.The demographic profile skewed young,with 66%of attendees in their 20s and 30s.The scientific program was organized by Prof.Seon-Ki Park(Chair),the Secretaries General from all three Associations,and the Local Organizing Committee.Reflecting the theme“Our Interconnected Earth,”the scientific program emphasized integrated approaches to climate systems,addressing climate change and environmental challenges through collaborative,transdisciplinary research.
基金the National Natural Science Foundation of China(No.52374347)Yulin Science and Technology Program Project(No.2024-SF-227)Key Research and Development Program of Shaanxi(No.2021GY-128).
文摘To address the kinetic constraints inherent in the catalytic combustion of pulverized coal injection under low heating-rate conditions within conventional air atmospheres,a drop tube furnace was utilized to simulate the catalytic combustion of pulverized coal(PC).The effects of gas composition,oxygen concentration,the type,and the content of catalysts on the combustion reactivity were systematically analyzed.Furthermore,the structural changes of unburned pulverized coal were also examined.Experimental results indicate that as the oxygen concentration increased from 21%to 79%,compared with the O_(2)/N_(2)condition,the increment in the burnout rate of PC under the O_(2)/CO_(2)condition increased from 3%to 23%.After the addition of catalysts,including hematite,metallurgical oil sludge,and light-burnt dolomite(LBD),under the condition of 21%oxygen concentration,the effects of the three catalysts under the O_(2)/CO_(2)condition were superior to those under the O_(2)/N_(2)condition.This trend was reversed under the conditions of 38%and 79%oxygen concentrations.In all atmospheres,the three catalysts can enhance the burnout rate of PC.Among them,LBD exhibits the most favorable effect,and there exists an optimal dosage.Mechanistic analysis through scanning electron microscopy,X-ray diffraction,and N_(2)adsorption-desorption reveals that under 21%O_(2)/79%CO_(2)conditions,high-concentration CO_(2)leads to the formation of pores,and additives accelerate the oxidation of C and the gasification of CO_(2)through oxygen transfer,thereby enhancing the burnout rate of PC.
基金supported by the National Natural Science Foun-dation of China(No.U22A20578)the guiding project of seizing the commanding heights of“self-purifying city”(No.IUE-CERAE-202402)+3 种基金the Science and Technology Department of Fujian Province(No.2022L3025)the National Key Research and Development Program(No.2022YFC3700304)the STS Plan Supporting Project of the Chinese Academy of Sciences in Fujian Province(No.2023T3013)Xiamen Atmospheric Environment Observation and Research Station of Fujian Province.
文摘Ambient ozone(O_(3))is generated through the reactions of nitrogen oxides and volatile organic compounds(VOCs)in sunlight,and the primary sources of RO_(x)radicals play a very important role in O_(3)photochemistry.However,as major precursors of RO_(x)radicals,the systematical evaluation of ClNO_(2),HCHO,and HONO impacts on O_(3)photochemistry remains limited.Here,we utilized the observations of ClNO_(2),HCHO,and HONO conducted in a coastal city of Southeast China during a photochemical O_(3)pollution episode,combined with model simulations to elucidate their impacts on RO_(x)radicals and atmospheric oxidation capacity(AOC),as well as O_(3)formation.Decreased concentrations of ClNO_(2)and HONO were observed after sunrise,while HCHO concentrations peaked in the daytime.HCHO photolysis contributed the largest(∼25%)to RO_(x)radical production around noon,while HONO photolysis(∼47%)dominated RO_(x)radical production in the morning and late afternoon,and VOCs consumed by Cl radical released via ClNO_(2)photolysis was more important(∼10%)in the early morning,similar to their effects on the AOC levels.The results of model simulations indicated that HCHO photolysis greatly enhanced the photochemical formation of O_(3),followed by HONO and ClNO_(2)photolysis.Except for reducing VOCs due to a VOC-limited regime,the impacts of HCHO photolysis as primary RO_(x)sources should be valued to inhibit the intensification of O_(3)pollution.Our study stressed the importance of primary RO_(x)sources for O_(3)photochemistry in coastal regions,provided new insights into elucidating the self-purifying effect of the atmospheric environment.
基金support from the National Natural Science Foundation of China(52172023 and 52302027).
文摘The Si_(3)N_(4)-bonded silicon carbide(SiC)bricks in the sloped zone of dry quenching coke ovens support the weight of upper refractory materials and equipment.These bricks endure frequent temperature fluctuations and intense abrasion from coke dust,demanding extremely high performance.After three years of service,an analysis of the Si_(3)N_(4)-bonded SiC bricks revealed that oxidation,which reduces thermal shock resistance,is the primary cause of degradation.In the unused Si_(3)N_(4)-bonded SiC bricks,short columnar β-Si_(3)N_(4) forms an interwoven network around SiC particles and contains a small amount of plate-like Si_(2)N_(2)O.Under the complex N_(2)(84.42 vol.%)-CO_(2)(10.44 vol.%)-CO(4.43 vol.%)-H_(2)(0.56 vol.%)-O_(2)(0.15 vol.%)atmosphere in the dry quenching coke oven,O_(2)(0.15 vol.%)exhibits a stronger oxidizing effect than CO_(2)(10.44 vol.%)and CO(4.43 vol.%),making it the primary oxidizing agent.The short columnarβ-Si_(3)N_(4) is more susceptible to oxidation than the particulate SiC.Based on thermodynamic and kinetic analyses,the chemical stability of the phases in Si_(3)N_(4)-bonded SiC bricks ranks from strongest to weakest as follows:Si_(2)N_(2)O,SiC,Si_(3)N_(4).Future development of Si_(2)N_(2)O-bonded SiC bricks could improve the longevity of refractory materials in the sloped zone of dry quenching coke ovens.
基金National Natural Science Foundation of China(Grant Nos.42174192,12241101,and 91952111).
文摘Internal gravity waves(IGWs)are critical in driving Martian atmospheric motion and phenomena.This study investigates Martian IGWs by using high-resolution data from China’s Tianwen-1 mission and the National Aeronautics and Space Administration’s Mars Global Surveyor(MGS)by the radio occultation(RO)technique.Key IGW parameters,such as vertical and horizontal wavelengths,intrinsic frequency,and energy density,are extracted based on vertical temperature profiles from the Martian surface to~50 km altitude.Data reveal that the Martian IGWs are predominantly small-scale waves,with vertical wavelengths between 6 and 13 km and horizontal wavelengths extending to thousands of kilometers.These waves propagate almost vertically and exhibit low intrinsic frequencies close to the inertial frequency,with the characteristic of low-frequency inertial IGWs.Tianwen-1 data indicate stronger IGW activity,higher energy density,and less dissipation than MGS data in the northern hemisphere.Moreover,MGS data in the southern hemisphere show higher buoyancy frequencies and lower vertical wavelengths,suggesting more stable atmospheric conditions conducive to IGW propagation.These extracted IGW characteristics can enhance our understanding of the atmospheric dynamics on Mars and contribute valuable information for parameterization in global circulation models.
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 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 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(62073034)。
文摘The parachute deployment conditions during the terminal entry phase in Mars landing missions exhibit critical impact on landing precision.In this article,aiming at the requirements of safe parachute deployment and accurate landing,a multidimensional parachute deployment box for determining deployment condition during Mars landing was proposed.First,an extremerange optimization model was established,synthesizing the dynamics and constraints of both parachute descent and powered descent phases.Then,on the basis of the two-dimensional altitude-velocity deployment box,a multi-dimensional parachute deployment box characterized by altitude,velocity,flight-path angle,and extreme range was constructed through the integration of extreme range information.Furthermore,an evaluation index for landing precision was formulated and a deployment control logic was proposed for minimizing landing deviation.Finally,the proposed deployment box was simulated in a Mars landing mission.The results demonstrate that the proposed box effectively satisfies safe deployment and landing precision demands,eliminating the range-to-go error at the terminal of the entry phase.
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This work is supported by the B-type Strategic Priority Program of the Chinese Academy of Sciences (Grant No. XDB4100000)the pre-research Project on Civil Aerospace Technologies No. D020105 funded by CNSAthe Strategic Priority Research Program of Chinese Academy of Sciences (Grant XDA17010404, XDA17010201)。
文摘In this study, we present an innovative Mars Ionosphere-Thermosphere Model(MITM), which is a time-dependent, threedimensional(3-D) model that comprehensively represents the self-consistently coupled thermosphere and ionosphere of Mars within the altitude range of 70-300 km. The model incorporates an extensive range of parameters, including neutral number densities of CO_(2), CO,O, O_(2), N_(2), NO, N(^(2)D), N(^(4)S), Ar, and He;ion number densities of CO_(2)^(+), CO^(+), O^(+), O_(2)^(+), N_(2)^(+), NO^(+), N^(+) ions, and electrons;neutral temperature;and neutral wind fields. The MITM code employs a high-resolution grid system in a spherical geographical coordinate system, with a horizontal resolution of 5° latitude by 7.5° longitude. This altitude-resolved grid system enables accurate depiction of spatial variations in the Martian thermosphere and ionosphere. To showcase the capabilities of the MITM, we present two simulation cases: one during the equinox and another during the solstice. Both simulations reproduce key features of the Martian thermosphere and ionosphere including the characteristics of horizontal circulation, diurnal variations in chemical composition, and distribution of electron density. The MITM offers a robust framework for understanding the intricate interactions and processes that shape the Mars thermosphere and ionosphere,which are crucial for enhancing our understanding of Martian upper atmosphere and ionosphere.
